JP3353545B2 - Electric vehicle drive control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric vehicle drive control device mounted on an electric vehicle such as an electric scooter or an electric vehicle and controlling a motor for driving wheels.

[0002]

2. Description of the Related Art In electric vehicles such as electric scooters,
A brushless DC motor is often used as a motor for driving wheels, and the motor is controlled by a drive control device using a microcomputer.

FIG. 13 shows a drive control device conventionally used in an electric vehicle using a brushless DC motor. In FIG. 13, reference numeral 1 denotes a rotor 1A having two-pole magnet fields 1a1 and 1a2; This is a brushless DC motor including a stator 1B having three-phase armature coils Au to Aw arranged with a phase difference of 120 degrees and star-connected. The output shaft of the electric motor 1 is directly connected to the drive wheels of the vehicle, or is connected via a reduction gear. Since no clutch is provided between the electric motor and the drive wheels, the electric motor is driven from the outside during braking, downhill, etc. At this time, the electric motor 1 acts as a synchronous generator. Generates AC voltage.

[0004] Reference numeral 2 denotes a position detector comprising a Hall IC or the like.
This position detector detects the relative position of the rotor with respect to each of the armature coils Au to Aw.

In FIG. 13, 3 is a battery, 4 is a key switch operated by the driver, 5 is an excitation coil 5a which is excited when the key switch 4 is closed, and 5 is a key switch which is excited when the excitation coil 5a is excited. A main relay 6 having a closing contact 5b, 6 is an armature coil Au to A of the electric motor 1
Inverter-type switch circuit for supplying a drive current to w and commutating the drive current, 7 a switch drive circuit for providing a drive signal to a switch element of a switch circuit 6, 8 a control unit, and 9 a vehicle An accelerator sensor 10 for detecting the position of a speed adjusting member operated by the driver to adjust the traveling speed is a surge absorbing element connected between the DC input terminals of the switch circuit 6.

The switch circuit 6 includes switch elements Su to S
w and Sx to Sz are bridge-connected, and feedback diodes Du, Dv, Dw, and Dx are connected to both ends of the switch elements Su, Sv, Sw and Sx, Sy, Sz, respectively.
Dy and Dz are connected in antiparallel. In the illustrated example, a field effect transistor (FET) is used as each switch element, and the common connection point of the drains of the FETs constituting the switch elements Su to Sw becomes the DC input terminal 6a on the positive polarity side, and the switch elements Sx to Sz. Is connected to the DC input terminal 6b on the negative polarity side. The sources of the FETs constituting the switching elements Su to Sw and the switching elements Sx to Sz, respectively.
Are three-phase output terminals 6u to 6w.

When the switch circuit 6 is viewed from the side of the motor 1, a full-wave bridge rectifier circuit is constituted by the diodes Du to Dw and Dx to Dz, and the motor 1 is driven from the outside, and the armature coil When a three-phase AC voltage is induced in Au to Aw, diodes Du to Dw and Dx
A regenerative charging current flows to the battery 3 through the full-wave bridge rectifier circuit consisting of .about.Dz and the contact 5b of the main relay 5.

The switch drive circuit 7 supplies drive signals u to w and x to z to the switch elements Su to Sw and Sx to Sz constituting the switch circuit 6, respectively. It comprises a circuit 7A and a drive circuit 7B.

The control unit 8 has a CPU 12, which has an output of the position detector 2, an output of the accelerator sensor 9, a detected value of the output voltage VB of the battery 3, and a battery 3 detected by the temperature sensor 15. The detected value of the temperature, the detected value of the drive current of the motor obtained by amplifying the voltage across the resistor R1 by the amplifier AMP (1), and the voltage obtained across the resistor R2 by the amplifier AMP (2) A detected value of the regenerative charging current, a detected value of the voltage between the positive DC input terminal of the switch circuit 6 and the ground detected by the voltage dividing circuit 16, a detected value of the driving current held in the latch circuit 17,
A detected value of the temperature of the switch circuit 6 detected by the temperature sensor 18 and a detected value of the winding temperature of the electric motor 1 detected by the temperature sensor 19 are input. Of these signals, analog signals are converted to digital signals through an A / D terminal provided in the CPU and read into the CPU.

In this example, a drive control section is constituted by the switch drive circuit 7 and the control unit 8. The control unit 8 is provided with a ROM or EE (not shown) by the CPU 12.
By executing the program stored in the PROM, the switch elements Su to Sw and Sx to Sz of the switch circuit 6 are turned on and off in order to adjust the magnitude of the drive current flowing through the armature coils Au to Aw and perform commutation. In addition to realizing the switch control means for controlling, the display control means for controlling the display 13 for performing various displays including a warning display of an abnormal state, and the electric motor to the battery when the electric motor is driven from the outside. A regenerative current control unit for controlling a flowing regenerative charging current is realized.

The switch control means realized by the CPU 12 generates a drive instruction signal and a current value instruction signal,
These signals are applied to the drive circuit 7B through the interface circuit 7A. Here, the drive instruction signal is a signal for instructing a switch element that needs to be turned on among the switch elements constituting the switch circuit 6, and the current value instruction signal is a signal for giving the magnitude of the drive current flowing through the armature coil. It is.

The drive circuit 7B supplies a drive signal having a predetermined time width to the upper side switch elements Su to Sw in response to the drive instruction signal and the current value instruction signal, and switches the lower side switch elements Sx to Sz. And a pulse width modulated drive signal that changes with a predetermined on-duty ratio. As a result, of the switch elements Su to Sw on the upper side of the bridge of the switch circuit, the switch element to which the drive signal is applied conducts only during the time when the drive signal is applied, and the switch elements Su to Su on the lower side of the bridge are provided. Among the switches Sw, the switch element to which the pulse width modulated drive signal is applied is turned on / off at a predetermined duty ratio, and a pulse width modulated drive current flows through an armature coil of a predetermined phase.

In the illustrated example, the output of the latch circuit 17 for latching the detection value of the drive current or the amplifier AMP is used.
The output of (1) is input to the drive circuit 7B. The drive circuit takes in the detected value of the drive current and performs control to keep the drive current flowing through the armature coils Au to Aw at a predetermined limit value or less.

The display control means gives a drive signal to the switch elements 14a to 14d composed of transistors and the like, and displays a warning on the display 13 composed of a light emitting diode, a buzzer or the like, a display of the state of each part (for example, a temperature display), etc. Is performed.

In the drive control device shown in FIG. 13, the output voltage of the battery 3 is input to the DC-DC converter 20 through the key switch 4, and the output voltage (56V in this example) of the battery 3 is output by the DC-DC converter 20. 12
V DC voltage. DC-DC converter 20
The DC voltage obtained from the excitation coil 5a of the main relay 5
And the power supply circuit 21 of the control unit 8, the power supply input terminals of the interface circuit 7A and the drive circuit 7B of the switch drive circuit 7, both ends of the potentiometer constituting the accelerator sensor 9, and the power supply terminal of the display 13. And lighting load of headlamps, blinkers, etc.
2 is applied. Power supply circuit 21 of control unit 8
Converts the 12V voltage obtained from the converter 20 into a 5V DC constant voltage and supplies power to the power supply terminal of the CPU.

In the drive control device shown in FIG. 13, when the key switch 4 is closed by the driver, DC-DC
Since the converter 20 outputs a DC voltage of 12 V, the contact of the main relay 5 is closed, and the output voltage of the battery 3 is applied between the DC input terminals of the switch circuit 6. The control unit 8 determines a phase sequence to be excited from a position detection signal given from the position detector 2 and a rotation direction command signal given by means (not shown), and sends a drive signal to a predetermined switch element of the switch drive circuit 7. A drive instruction signal for giving an instruction is given to the switch drive circuit 7.

The control unit 8 also obtains information on the rotational speed of the motor from the rectangular wave signal supplied from the position detector 2 (or from a separately provided encoder), and supplies this rotational speed information from the accelerator sensor 9. The magnitude of the drive current (average value) required to match the rotation speed of the motor to the designated speed is compared with the designated speed information, and a current value indication signal for giving the magnitude of the calculated drive current is calculated. This is given to the switch drive circuit 7.

The drive circuit 7B responds to a drive instruction signal and a current value instruction signal given from the control unit 8,
A drive signal having a predetermined time width is given to one of the switch elements Su to Sw on the upper side to make the switch elements conductive, and the switch element S on the lower side is selected.
An intermittent (PWM-modulated) drive signal is applied to one switch element selected from x to Sz at an on-duty ratio corresponding to the magnitude of the drive current to turn the switch element on and off. As a result, the switch elements Su to Sw on the upper side and the switch elements Sx to Sx on the lower side of the switch circuit 6 are set.
Sz is turned on one by one in a predetermined order, a drive current is supplied to the motor, and the motor is rotated at the designated speed.

When the speed adjusting member such as the accelerator grip is returned to stop the vehicle, the motor is driven from the outside while the vehicle is decelerating. At this time, the motor 1 functions as a synchronous generator and induces a three-phase AC voltage in the armature coils Au to Aw. This voltage is applied to the diodes Du to Dw.
, And a regenerative charging current to the battery 3 through the full-wave rectifier circuit constituted by Dx to Dz and the contact 5b of the main relay. As a result, the battery is charged, and the rotation of the electric motor is braked, so that the vehicle is decelerated. The same applies to the case where the electric motor is driven from the outside when going down a hill.

The control unit 8 controls the electric motor 1 as described above.
The regenerative charging current value detected by the voltage across the resistor R2 when the regenerative charging current flows from the battery 3 to the battery 3 is input, the magnitude of the regenerative charging current is monitored, and the regenerative charging current is set. When the value exceeds the value (upper limit value of the charging current of the battery), a drive signal for giving a trigger signal to the switch elements Sx to Sz on the lower side of the switch circuit 6 at the same time is given to the switch drive circuit 7. As a result, the switch elements Sx to Sz are simultaneously turned on, the armature coils Au to Aw are short-circuited, the supply of the charging current to the battery 3 is stopped, and the motor is decelerated by applying a short brake to the motor.

[0021]

In the conventional electric vehicle drive control device, when the key switch 4 is closed, the DC-DC converter 20 operates to supply power to the control unit 8 and the switch drive circuit 7. At the same time, the contact 5b of the main relay 5 is turned on to supply power to the electric motor. When the key switch 4 is opened, DC-D
The input of the C converter becomes zero and the contact 5b of the main relay 5
Opens and the battery is disconnected from the motor,
The power of the control unit 8 and the switch drive circuit 7 is turned off, and the operation of the control unit and the switch drive circuit stops.

As described above, in the conventional drive control device, the state (ON or OFF) of the contact 5b of the main relay 5 is determined only by the ON / OFF of the key switch 4, so that the vehicle is running by inertia or a long descent. When a large regenerative charging current flows from the motor to the battery for a long time, such as when traveling on a hill, the temperature of the motor or the switch circuit becomes excessively high, or if the battery becomes overcharged, the main relay There has been a problem that the contacts cannot be opened to protect the motor and the battery.

An object of the present invention is to provide an electric vehicle drive system capable of opening a contact of a main relay to protect an electric motor or a battery when an abnormal state such as overheating of an electric motor or overcharging of a battery occurs. It is to provide a control device.

[0024]

SUMMARY OF THE INVENTION The present invention comprises a battery,
A DC switch comprising a key switch operated by a driver, a main relay having a contact that closes when excited, a plurality of switch elements connected in a bridge, and diodes connected in anti-parallel to both ends of each switch element. The output voltage of the battery is applied between the input terminals through the contacts of the main relay, and the output terminal is connected to the armature coil of the brushless DC motor for driving the wheels, and the magnitude of the drive current flowing through the armature coil Current control for controlling the regenerative charging current flowing from the motor to the battery when the motor is driven from the outside, and switch control means for controlling the on / off of the switch element of the switch circuit to perform the adjustment and commutation of the motor Means and an abnormal state detecting means for detecting the presence or absence of an abnormal state of a predetermined monitoring target portion and a warning display of the abnormal state. An electric vehicle drive control device, comprising: a control unit that realizes display control means for controlling a display by a CPU; and a switch drive circuit that receives a signal provided from the control unit as an input and provides a drive signal to a switch element of a switch circuit. It is related to.

In the present invention, there is provided a DC power supply circuit for supplying a power supply voltage to the drive control unit when the voltage of the battery is input through the key switch and the key switch is closed. The control unit includes a main relay excitation switch for turning on and off an excitation current of the main relay, and when no abnormality is detected by the abnormal state detection means, turns on the main relay excitation switch means to detect an abnormal state. The main relay excitation control means for turning off the main relay excitation switch means when the abnormality is detected by the means is further realized.

The part to be monitored is a part that may have a serious effect on running when an abnormality occurs or a failure may occur if an abnormal state is left unattended. The part to be monitored is, for example, the armature coil of the electric motor 1, the switch element of the switch circuit 6, the battery 3, and the like. The abnormal states to be monitored include an abnormal increase in the temperature of the armature coil, an abnormal increase in the temperature of the switch element of the switch circuit, an abnormal increase in the temperature of the battery, and an overcharge state of the battery.

It is preferable that a voltage between the DC input terminals of the switch circuit is also input to the DC power supply circuit.

In the present invention, the power supply voltage is supplied to the switch drive circuit by a DC power supply circuit that receives the voltage between the DC input terminals of the switch circuit, and the power supply voltage is supplied to the control unit by a battery provided for driving the control unit. You may give it. In this case, the voltage of the battery is applied to the excitation coil of the main relay through the key switch. In addition, the control unit detects that the rotation speed of the motor has become zero or less than the set value in a state where the key switch is detected to be open outside the main relay excitation control means. Sometimes, a main relay de-energizing means for turning off the main relay excitation control switch and turning off the main relay in a non-excited state is realized.

Furthermore, in the present invention, when the voltage of the battery is input to the input terminal through the key switch and the voltage between the DC input terminals of the switch circuit is input to the input terminal and the key switch is closed, and when the key switch is closed, A DC power supply circuit for applying a power supply voltage to the switch drive circuit and the control unit when a voltage appears between the DC input terminals;
It is also possible to provide an auxiliary relay having a contact connected between the battery and the input terminal of the DC power supply circuit and closing the contact when excited to input the output voltage of the battery to the DC power supply circuit when excited. .

In this case, the control unit is provided with a main relay excitation switch for turning on and off the main relay excitation current and an auxiliary relay excitation switch for turning on and off the auxiliary relay excitation current, and the key switch is closed. A key that turns on the main relay excitation switch when the abnormal state detection means is not detecting an abnormality in the status, and turns off the main relay excitation switch when the abnormal state detection means is detecting an abnormality. The main relay excitation control means when the switch is closed and the main relay excitation when the condition for flowing the regenerative charging current from the motor to the battery is satisfied in a state where the key switch is open and the abnormal state detecting means does not detect an abnormality. Turn on the switch and turn on the main relay excitation switch when the key switch is open and the abnormal condition detecting means detects an abnormality. When the key switch is opened, the main relay excitation control means is turned off, and when the key switch is open and the abnormality detection means does not detect an abnormality, the auxiliary relay excitation switch is turned off. And an auxiliary relay excitation control means for turning on the auxiliary relay excitation switch when an abnormality is detected.

[0031]

With the above arrangement, when the key switch is closed, the DC power supply circuit supplies the power supply voltage to the drive control section, so that the drive control section starts operating and the abnormality detecting means sets the predetermined monitoring target. Detects whether there is any abnormality in the part. As a result, if no abnormality is detected, the main relay energizing switch is turned on to excite the main relay, and the power can be supplied from the battery to the electric motor. Further, when an abnormality occurs in the monitoring target portion during the operation, the motor is stopped because the main relay excitation switch control means turns off the main relay excitation switch means. As a result, it is possible to eliminate the possibility that the operation is continued in a state where the abnormal state has occurred and a serious failure occurs. When the key switch is opened after the motor stops, the drive control unit stops operating because the DC power supply circuit stops supplying the power supply voltage to the drive control unit.

When the key switch is opened while the vehicle is running, the motor is driven from the outside, and a voltage is induced in the armature coil. This induced voltage is rectified by a full-wave rectifier circuit composed of a diode connected in reverse parallel to each switch element of the switch circuit, and appears as a DC voltage at both ends (between DC input terminals) of the switch circuit. Therefore,
If the voltage between the DC input terminals of the switch circuit is input to the DC power supply circuit as described above, the drive control unit can be operated even when the key switch is accidentally opened during driving, and the abnormal state And a control operation such as a warning display operation can be performed.

Further, as described above, the power supply voltage is supplied to the switch drive circuit by the DC power supply circuit which receives the voltage between the DC input terminals of the switch circuit, and the power supply voltage is supplied to the control unit by the battery provided for driving the control unit. When the key switch is opened, the contact of the main relay can be kept on even when the key switch is opened. And the motor can be decelerated. If the motor is overheated or the switch element of the switch circuit is overheated due to the flow of the regenerative charging current, the contact of the main relay can be opened to immediately cut off the regenerative charging current.

An auxiliary relay is provided to input the voltage of the battery to the DC power supply circuit through the contact of the auxiliary relay. The main relay excitation control means when the key switch is open, the main relay excitation control means when the key switch is closed, and the auxiliary relay excitation If the control means and the control unit are realized by a control unit, the contact of the main relay can be closed and the regenerative charging current can flow when the key switch is accidentally opened during operation, so that safety can be improved. . When an abnormality occurs with the key switch open, the contact of the auxiliary relay can be closed and the power supply of the control unit can be secured. You can encourage them to take it.

[0035]

FIG. 1 shows the configuration of hardware according to an embodiment of the present invention. In FIG. is there.

In FIG. 1, 1 is a brushless DC motor, 3 is a battery, 4 is a key switch operated by a driver, 5 is a main switch having an exciting coil 5a and a contact 5b which closes when the exciting coil 5a is excited. A relay 6 is a bridge-type switch circuit for supplying a drive current to the armature coils Au to Aw of the electric motor 1 and performing commutation of the drive current, and 7 is a switch for giving a trigger signal to a switch element of the switch circuit 6. A drive circuit, 8 is a control unit, 9 is an accelerator sensor for detecting the position of a speed adjusting member (for example, an accelerator grip or an accelerator pedal) operated by a driver to adjust the traveling speed of the vehicle, and 10 is a switch circuit 6. It is a surge absorbing element connected between DC input terminals.

A brushless DC motor generally has a rotor having a magnet field and 360 / n degrees (n is an integer of 2 or more).
And a stator having an n-phase armature coil that is provided with a phase difference and is star-connected. The illustrated electric motor 1 comprises a rotor 1A having two-pole magnet fields 1a1 and 1a2, and a stator 1B having three-phase armature coils Au to Aw arranged with a phase difference of 120 degrees. The child coils Au to Aw are star-connected.

A position detector 2 for detecting a relative position of the rotor with respect to the stator is provided on the side of the stator 1B. The position detector 2 includes, for example, three halls ICHu, Hv, Hw (not shown) provided for each of the armature coils Au to Aw of the stator.
The polarity of the magnetic pole of the rotor is detected by these Hall ICs, and the relative position of the rotor to each of the armature coils Au to Aw is detected. The three Hall ICs are arranged at intervals of 120 degrees, and each Hall IC holds a high level (hereinafter also referred to as H level) state when the detected magnetic pole of the rotor 1A is, for example, an N pole. , And S poles, generate rectangular wave signals eu to ew that maintain a low level (hereinafter also referred to as L level) state. Square wave signal eu
FIG. 4A shows an example of a change in the rotation angle .theta.
This is shown in (C).

The output shaft of the electric motor 1 is directly connected to the driving wheels of the vehicle or connected via a speed reducer. Generally, no clutch is provided between the electric motor and the drive wheels, so that the electric motor is driven from the outside during braking or when going down a hill. At this time, the electric motor 1 acts as a synchronous generator. Generates AC voltage.

In the illustrated example, the output voltage of the battery 3 is applied to the DC-DC converter 20 via the key switch 4, and the output voltage of the battery 3 (56V in this example) is
The voltage is converted into a DC voltage of 12 V by the C-DC converter 20. 12V obtained from DC-DC converter 20
Is applied to the exciting coil 5a of the main relay 5 and the lighting load 22 such as a headlamp or a blinker.

In general, the bridge-type switch circuit 6 is a circuit in which unidirectional switch elements that conduct only while a drive signal is being applied are bridge-connected, and feedback diodes are connected in anti-parallel to both ends of each switch element. Thus, the output voltage of the battery 3 is applied between the DC input terminals through the contact 5b of the main relay 5.

Here, the bridge connection of the switch elements means that the switch elements are bridge-connected in the same manner as in a known diode bridge full-wave rectifier circuit. Generally, a bridge circuit having this type of connection is provided with a plurality of switch element series circuits comprising two switch elements connected in series with the same polarity, and the plurality of switch element series circuits are connected in parallel with each other. Has a circuit configuration connected to the In general, when an n-phase brushless DC motor is driven using a bridge-type switch circuit, a switch circuit configured by connecting 2n switch elements in a bridge configuration (configured by connecting n switch element series circuits in parallel) Switch circuit).

In the switch circuit having such a circuit configuration, a common connection point at one end and a common connection point at both ends (both ends of the switch circuit) of the n switch element series circuits are connected to a pair of DC input terminals (battery). Are applied), and n terminals drawn from the connection points of the respective switch elements of the n switch element series circuits are output terminals (terminals connected to the n-phase armature coil). I do.

In the present specification, in a switch circuit configured by bridge-connecting switch elements, a switch element located between a DC input terminal and an output terminal on the positive polarity side is a switch element or a switch element forming the upper side of the bridge. The switch element located between the DC input terminal and the output terminal on the negative polarity side is called the switch element on the upper side of the bridge, and is called the switch element forming the lower side of the bridge or the switch element on the lower side of the bridge.

As described above, when a switch circuit configured by connecting the switch elements in a full-wave bridge is provided between the DC power supply and the armature coil of the n-phase brushless DC motor, the n pieces of the upper side of the bridge are formed. By turning on the switch elements and the n switch elements constituting the lower side of the bridge one by one in a predetermined order, the drive current is sequentially commutated to the n-phase armature coil, and the motor can be rotated. .

The switch circuit 6 used in this embodiment is
A switch element series circuit formed by connecting switch elements Su and Sx in series, a switch element series circuit formed by connecting Sv and Sy in series, and a switch element formed by connecting Sw and Sz in series The series circuits are connected in parallel (three-phase full-wave bridge connection), and feedback diodes Du, Dv, Dw and Dx, Dy, are connected to both ends of the switch elements Su, Sv, Sw and Sx, Sy, Sz, respectively.
Dz are connected in antiparallel.

In the illustrated switch circuit 6, a field effect transistor (FET) is used as each switch element, and the common connection point of the drains of the FETs constituting the switch elements Su to Sw is the positive DC input terminal 6a. The common connection point of the sources of the FETs constituting the switching elements Sx to Sz is the DC input terminal 6b on the negative polarity side. Further, F which constitutes the switching elements Su to Sw, respectively.
The connection point between the source of the ET and the drains of the FETs constituting the switch elements Sx to Sz is a three-phase output terminal 6u.
６6w.

When the switch circuit 6 is viewed from the side of the motor 1, a full-wave bridge rectifier circuit is constituted by the diodes Du to Dw and Dx to Dz, and the motor 1 is driven from the outside, and the armature coil When a three-phase AC voltage is induced in Au to Aw, diodes Du to Dw and Dx
A regenerative charging current flows to the battery 3 through the full-wave bridge rectifier circuit consisting of .about.Dz and the contact 5b of the main relay 5.

In this example, the switching elements Su to Sw located between the DC input terminal 6a on the positive polarity side of the switch circuit 6 and the output terminal are the switching elements on the upper side of the bridge, and the DC input terminal on the negative polarity side. Switch elements Sx to Sz located between 6b and the output terminal are switch elements on the lower side of the bridge.

The DC input terminal 6a on the positive polarity side of the switch circuit 6 is connected to the positive terminal of the battery 3 via the contact 5b of the main relay. The DC input terminal 6b on the negative polarity side of the switch circuit 6 is grounded through a current detecting resistor R1, and the negative electrode terminal of the battery 3 is grounded through a charging current detecting resistor R2. The three-phase output terminals 6 u, 6 v and 6 w of the switch circuit 6 are connected to terminals of the three-phase armature coils Au to Aw of the brushless DC motor 1 on the opposite side to the neutral point.

In the present invention, a DC power supply circuit 30 is provided which supplies a power supply voltage to the switch drive circuit 7 and the control unit 8 using the battery 3 as a power supply. It is inputted through the key switch 4 and the diode D01. The DC power supply circuit 30 steps down the output voltage (56 V) of the battery 3 and outputs a constant DC voltage (15 V in this example).

In this embodiment, the voltage between the DC input terminals 6a and 6b of the switch circuit 6 is input to the DC power supply circuit 30 through the diode Do2, and the electric motor is driven from the outside, so that the armature coils Au to. When a voltage is induced in Aw, the induced voltage is reduced by diodes Du to Dw and Dw.
The current is rectified by a rectifier circuit composed of x to Dz and supplied to the DC power supply circuit 30.

The DC voltage obtained from the DC power supply circuit 30 is supplied to the power supply terminal of the switch drive circuit 7 and the control unit 8.
A power supply circuit 21 therein, a power supply terminal of the accelerator sensor 9,
And a power supply terminal of the display 13. The power supply circuit 21 of the control unit 8 converts the voltage of 15 V supplied from the DC power supply circuit 30 into a constant DC voltage of 5 V,
2 power supply terminal. A diode 35 is inserted between the output terminal of the DC power supply circuit 30 and the input terminal of the power supply circuit 21.

The control unit 8 includes a CPU 12 and switches the control unit 8 to adjust the magnitude of the drive current flowing through the armature coils Au to Aw and to perform commutation by a program stored in a ROM or an EEPROM (not shown). Switch control means (means for generating drive instruction signals u 'to w', x 'to z' and a PWM signal) for turning on and off the switch elements of the circuit 6; A regenerative current control means for controlling regenerative charging current flowing to a battery with a voltage induced in an armature coil of a motor;
3 implements a display control means for performing various display operations such as a warning display and a display of a state of each unit (for example, a temperature display). Reference numerals 14a to 14c denote transistors constituting a switch which conducts when a trigger signal is given from the CPU 12 and which energizes the display means of the display 13.

The output of the position detector 2, the output of the accelerator sensor 9, the detected value of the output voltage VB of the battery 3, the detected value of the temperature of the battery 3 detected by the temperature sensor 15, The detected value of the drive current of the motor obtained by amplifying the voltage across R1 by the amplifier AMP (1) and the voltage across the resistor R2 to the amplifier AMP
The detected value of the regenerative charging current obtained by amplification in (2), the detected value of the voltage between the positive DC input terminal of the switch circuit 6 and the ground detected by the voltage dividing circuit 16, and held by the latch circuit 17 The detected value of the drive current, the detected value of the temperature of the switch circuit 6 detected by the temperature sensor 18, the temperature sensor 1
9 divides the detected value of the winding temperature of the electric motor 1 and the voltage between the connection point between the key switch 4 and the DC-DC converter 20 and the ground by a voltage dividing circuit composed of a series circuit of resistors R10 and R11. The key switch state detection signal Vk obtained as described above is input. Of these signals, analog signals are converted to digital signals through an A / D terminal provided in the CPU and read into the CPU.

The CPU 12 of the control unit 8 sends drive instruction signals u 'to w', x 'to
Generate z 'and PWM signals. These signals are supplied to the drive circuit 7B through the interface circuit 7A. The drive instruction signals u 'to w' and x 'to z' are signals for instructing which of the switch elements constituting the switch circuit 6 need to be made conductive, and the PWM signal is a drive signal to be passed through the armature coil. It is a pulse signal that is intermittent at a duty ratio corresponding to the average value of the current.

The switch drive circuit 7 is a circuit for supplying drive signals u to w and x to z to the switch elements Su to Sw and Sx to Sz which constitute the switch circuit 6, respectively. It comprises a circuit 7A and a drive circuit 7B.

The drive circuit 7B outputs the drive instruction signals u 'to u'.
A drive signal having a predetermined pulse width is given to the switch elements Su to Sw on the upper side of the bridge of the switch circuit 6 according to w 'and x' to z 'and the PWM signal, and the switch elements Sx to Sz on the lower side of the bridge are provided. And a pulse width modulated drive signal that changes with a predetermined on-duty ratio.
As a result, of the switch elements Su to Sw on the upper side, the switch element to which the drive signal is applied conducts for a time corresponding to the pulse width of the drive signal, and the switch element Su on the lower side.
, The switch element to which the pulse width modulated drive signal is applied turns on and off at a predetermined duty ratio, and the pulse width modulated drive current flows through the armature coil of a predetermined phase. FIG. 4A shows a Hall IC constituting the position detector 2.
To (C) square wave signals (position detection signals) eu to e
When w occurs, the switching elements Su to Sw and Sx to
Sz is shown in FIGS. 4 (D) to (F) and (G) to (I), respectively.
It operates on and off like. The waveforms in FIGS. 4D to 4F and 4G to 4I show the case where the on-duty ratio of the drive current is 100%.

In the illustrated example, the output of the latch circuit 17 for latching the detected value of the drive current or the amplifier AMP is used.
The output of (1) is input to the drive circuit 7B. The drive circuit 7B takes in the detected value of the drive current and performs control to keep the drive current flowing through the armature coils Au to Aw at a predetermined limit value or less.

FIG. 5 shows an example of a more detailed configuration of the periphery of the switch drive circuit 7. The CPU 12 has output ports P00 to P06, and the output ports P00 to P06.
From P05, the switching elements Su, Sv, Sw, Sx
, Sy, Sz drive instructing signals u ′, v that go to a high level (H level) when instructing to give a drive signal
', W', x ', y', z 'are output. From the output port Po6, a PWM signal having a pulse waveform intermittent at a predetermined duty ratio having a magnitude corresponding to the average value of the drive current is output.

The drive circuit 7B has input terminals Hin and Lin.
And control amplifiers 701a to 701c having
The drive instruction signals u ', v', w generated by the CPU 12 are respectively applied to the input terminals Hin of the control amplifiers 701a to 701c.
'Has been input through the interface 7A. Each control amplifier has two sets of output terminals t11, t12 and t21, t22.
When the potential of the input terminal Hin becomes H level and L level, the potentials of the output terminals t11 and t12 become H level and L level, respectively, and the potential of the input terminal Lin becomes H level and L level. When this happens, the potentials at the output terminals t21 and t22 become H level and L level, respectively. A Zener diode ZD2 is connected between the output terminals of the control amplifiers 701a to 701c, and the level of a signal obtained between the output terminals is limited by the Zener diode.

The PWM signal is input to a negative logic inverter IN1. The output of the inverter IN1 is supplied to the control amplifiers 701a to 701a through negative logic inverters INa to INc.
701c is input to the input terminal Lin. The DC power supply circuit 3 is connected to the output terminal of the inverter IN1 through the resistor R3.
0 output voltage is applied.

Control amplifiers 701a, 701b, 701c
Outputs the drive signals u, v, w from the respective output terminals t11, t12 while the drive instruction signals u ', v', w 'are at the high level. Further, the control amplifiers 701a, 701
1b and 701c are drive signals x, y, z pulse-width-modulated by the PWM signal from the respective output terminals t21, t22 while the drive instruction signals x ', y', z 'are at the high level. Is output. Control amplifiers 701a-7
Drive signals u, v, w obtained from the respective output terminals t11, t12 of the control amplifier 01c are supplied to the control terminals of the switch elements Su, Sv, Sw, and are obtained from the respective output terminals t21, t22 of the control amplifiers 701a to 701c. The drive signal x,
y and z are input to the control terminals of the switch elements Sx, Sy and Sz, respectively.

The latch circuit 17 is provided to perform a control to immediately cut off the drive current and prevent the armature coil from burning when an excessive drive current flows due to a short circuit accident of the armature coil or the like. ing. Latch circuit 1 shown
Reference numeral 7 denotes a comparator CP1, a voltage dividing circuit composed of a series circuit of resistors R4 and R5, a negative logic inverter IN2 having an input terminal connected to the output terminal of the comparator CP1, a cathode grounded, and an anode connected to a resistor. DC power supply circuit 3 through R6
A thyristor Th1 connected to the output terminal on the positive electrode side of 0,
A resistor R7 is connected between the gate of the thyristor Th1 and the output terminal of the inverter IN2. The output of the amplifier AMP (1) for amplifying the voltage (drive current detection signal) across the resistor R1 is input to the inverting input terminal of the comparator CP1, and the non-inverting input terminal of the comparator CP1 is connected to the non-inverting input terminal of the DC power supply circuit. A reference voltage Vr obtained by dividing the output voltage by a voltage dividing circuit composed of resistors R4 and R5 is input. The output terminal of the comparator CP1 is directly connected to the non-inverting input terminal. The voltage across the thyristor Th1 is input to a negative logic inverter IN1 ', and the output of the inverter IN1' is
The signals are input to the input terminals Lin of the control amplifiers 701a to 701c through inverters INa 'to INc' of negative logic. The output voltage of the DC power supply circuit 30 is applied to the output terminal of the inverter IN1 'through the resistor R3'.

In FIG. 5, a voltage proportional to the drive current flowing through the armature coils Au to Aw of the motor through the switch circuit 6 appears at both ends of the resistor R1. This voltage is used as a drive current detection signal. The drive current detection signal is the amplifier AM
When the driving current is amplified by P (1) and supplied to the inverting input terminal of the comparator CP1, and the driving current is equal to or smaller than the allowable value, the driving current detection signal supplied from the amplifier AMP (1) to the comparator CP1 is changed to the reference voltage Vr. Is lower than. In this state, since the potential of the output terminal of the comparator CP1 is at the H level, the output of the inverter IN2 is at the L level. At this time, since no trigger signal is given to the thyristor Th1, the thyristor Th1 is in the cutoff state, and the input signal of the inverter IN1 'is at the H level.
At this time, the output of the inverter IN1 'is at the L level, and the outputs of the inverters INa' to INc 'are at the H level. In this state, since the output of the latch circuit 17 does not affect the operation of the control amplifiers 701a to 701c, the control amplifiers 701a to 701c output a predetermined drive signal according to a drive instruction signal given from the CPU.

When the drive current exceeds the allowable value, the amplifier AM
Since the drive current detection signal supplied from P (1) to the comparator CP1 exceeds the reference voltage Vr, the output voltage of the comparator CP1 becomes L level, and the potential of the non-inverting input terminal of the comparator CP1 also becomes L level. Become. At this time, since the output of the inverter IN2 becomes H level, a trigger signal is supplied to the thyristor Th1, and the thyristor Th1 is maintained in a conductive state. Therefore, the input of the inverter IN1 'goes low, and the output of the inverter IN1' goes high. At this time, since the outputs of the inverters INa 'to INc' are at L level, the input signals of the input terminals Lin of the control amplifiers 701a to 701c are held at L level, and
The drive signals x to z output from the output terminals t21 and t22 of 1a to 701c are all at L level. Therefore, in this state, the switch elements Sx to Sz are kept in the off state, and the supply of the drive current to the electric motor 1 is stopped. This prevents the armature coils Au to Aw from burning out.

In this embodiment, the exciting coil 5 of the main relay 5
In order to control the energization of the
A transistor 33 is provided. The transistor 33 constitutes a main relay excitation switch. The collector of the transistor 33 is connected to one end of an excitation coil 5a of the main relay, and the other end of the excitation coil 5a is connected to a positive output terminal of the DC-DC converter 20. It is connected to the. The base of the transistor 33 is connected to a predetermined output port of the CPU 12, and when the drive signal Von is output from the output port, the transistor 33 is turned on and an exciting current flows through the exciting coil 5a of the main relay 5. It has become.

In this embodiment, a key switch state detecting circuit is constituted by a voltage dividing circuit composed of resistors R10 and R11. Also, the control unit 8 controls the switch element of the switch circuit 6 to turn on and off the switch element so as to adjust and commutate the magnitude of the drive current flowing through the armature coil, and to set the motor to be driven from the outside. A regenerative current control means for controlling a regenerative charging current flowing when the abnormal state is detected; an abnormal state detecting means for detecting the presence or absence of an abnormal state of a predetermined monitoring target portion; and an abnormal state detecting means when no abnormality is detected. Main relay excitation control means for turning on the transistor 33 (main relay excitation switch means) and turning off the transistor 33 when an abnormality is detected by the abnormal state detection means; And a display control means for controlling the display unit 13 for performing the display.

In the drive control device shown in FIG. 1, when the key switch 4 is closed by the driver, the output voltage (for example, 56 [V]) of the battery 3 is supplied to the DC power supply circuit 30 through the key switch 4 and the diode D01. Is entered.
DC power supply circuit 30 reduces the output voltage of battery 3 to 1
A DC voltage of 2 [V] is output, and this voltage is applied to the interface 7A of the switch drive circuit 7 and the power supply terminal of the drive circuit 7B. Since the output voltage of the DC power supply circuit 30 is also input to the power supply circuit 21 of the control unit 8, the power supply circuit 21 supplies the CPU 12 with a power supply voltage of 5 [v]. Thereby, the CPU 12 is activated. C
The PU 12 realizes an abnormal state detecting means by executing a predetermined program, and detects the presence or absence of an abnormality in each monitoring target portion based on information detected from a predetermined sensor. In the present embodiment, the battery 3,
The switch elements of the switch circuit 5 and the armature coils Au to Aw of the motor 1 are selected, and the temperature sensors 15, 18 and 19 are selected.
It is determined that the temperatures of the battery 3, the switch element of the switch circuit 6, and the armature coil of the electric motor are abnormally high, respectively, when the temperatures detected by the above each exceed the abnormality determination reference value. Further, it is determined whether or not the battery is in an overcharged state from the detected value of the voltage between both ends of the battery 3.

If no abnormality is detected in the monitoring target portion, the main relay excitation switch control means realized by the CPU and the predetermined process of the program outputs the drive signal Von from the output port of the CPU 12 to turn on the transistor 3. Turn on. As a result, the exciting current is supplied to the exciting coil 5a, so that the main relay 5 is excited and the contact 5b is closed. As a result, the output voltage of the battery 3 is applied between the DC input terminals 6a and 6b of the switch circuit 6.

The switch control means realized by the CPU 12 of the control unit 8 determines the phase sequence to be excited from the position detection signal given from the position detector 2 and the rotation direction command signal given by means (not shown). Drive instruction signals u ′ to w ′ and x ′ to z ′ for giving a drive signal to a predetermined switch element of the circuit 6 are given to the switch drive circuit 7.

The control unit 8 also obtains information on the rotational speed of the electric motor from a signal supplied from the position detector 2 (or from a separately provided encoder), and outputs this rotational speed information to an instruction given from the accelerator sensor 9. Compared with the speed information, calculate the magnitude (average value) of the drive current required to match the rotation speed of the motor to the specified speed, and change the pulse at a duty ratio corresponding to the calculated drive current. A PWM signal having a waveform is applied to the switch drive circuit 7.

The drive circuit 7B switches the switch elements Su to Sw on the upper side of the bridge of the switch circuit 6 according to the drive instruction signal and the PWM signal given from the control unit 8.
A drive signal having a predetermined time width is given to one of the switch elements selected from among them to make the switch element conductive, and one of the switch elements Sx to Sz selected from the lower side is selected.
An intermittent (PWM modulated) drive signal is applied to one of the switch elements at an on-duty ratio corresponding to the magnitude of the drive current to turn on and off the switch elements. As a result, the switch elements Su to Sw on the upper side and the switch elements Sx to Sz on the lower side of the switch circuit 6 are turned on one by one in a predetermined order, and a drive current is supplied to the electric motor to rotate the electric motor at the designated speed.

When the speed adjusting member such as the accelerator grip is returned to stop the vehicle, the motor is driven from the outside while the vehicle is decelerating. At this time, the motor 1 functions as a synchronous generator and induces a three-phase AC voltage in the armature coils Au to Aw. This voltage is applied to the diodes Du to Dw.
, And a regenerative charging current to the battery 3 through the full-wave rectifier circuit constituted by Dx to Dz and the contact 5b of the main relay. As a result, the battery is charged, and the rotation of the electric motor is braked, so that the vehicle is decelerated. The same applies to the case where the electric motor is driven from the outside when going down a hill.

The control unit 8 controls the motor 1 as described above.
When the regenerative charging current flows from the battery 3 to the battery 3, the regenerative charging current value detected by the voltage across the resistor R2 is input and the magnitude of the regenerative charging current is monitored. When the regenerative charging current exceeds a set value (upper limit of the charging current of the battery), a driving instruction signal for giving a driving signal to the switch elements Sx to Sz on the lower side of the switching circuit 6 at the same time is given to the switch driving circuit 7. Thereby, the switch elements Sx to Sz are simultaneously turned on to short-circuit the armature coils Au to Aw, the supply of the charging current to the battery 3 is stopped, and the motor is decelerated by applying a short brake to the motor.

FIG. 6 shows signal waveforms at various parts when the regenerative braking is applied when the switch drive circuit 7 is configured as shown in FIG. That is, when regenerative braking is applied, as shown in FIGS. 6A to 6C, drive instruction signals x 'to z' output from output ports P03 to P05 of the CPU.
At the same time, and in this state, a PWM signal having a pulse waveform that changes at a predetermined duty ratio is applied from the output port P06 to the switch drive circuit 7 as shown in FIG. As shown in FIGS. 6E to 6G, the drive signals x to z obtained from the control amplifiers 701a to 701c are simultaneously subjected to pulse width modulation by the PWM signal. At this time, for example, the drive current Iu flowing through the U-phase armature coil Au
Is as shown in FIG. 6 (H). In the figure, the armature coils Au to Aw are simultaneously short-circuited during the shaded period, and the induced voltage of the armature coils becomes substantially zero. The regenerative charging current is supplied to the battery through the full-wave rectifier circuit composed of the diodes Du to Dw and Dx to Dz and the contact 5b of the main relay 5. The waveform of the regenerative charging current Ic is as shown in FIG.

As described above, when the regenerative charging current is supplied when the motor is driven by the wheels, or when the short-circuit brake is applied by short-circuiting the armature coils Au to Aw, the motor is driven. Since the voltage induced in the armature coil when the vehicle is driven by the wheels does not become excessive, the elements constituting the switch circuit 6 can be protected from overvoltage, and the switch element has a low withstand voltage. Can be used.

The display control means realized by the CPU of the control unit 8 monitors the battery temperature, the battery voltage, the rotation state of the electric motor, the temperature of the electric motor, and the like. The display 13 is operated to display a warning.

When the voltage between the DC input terminals 6a and 6b of the switch circuit 6 is input to the DC power supply circuit 30 as in the above-described embodiment, the motor is driven when the motor is driven from the outside. Since the power supply voltage can be applied to the switch drive circuit 7 and the control unit 8 by the voltage induced in the child coils Au to Aw, even when the key switch 4 is opened by mistake when traveling downhill, etc. By operating the switch drive circuit 7 and the control unit 8, a control operation such as a warning display can be performed, and safety can be improved.

In the above embodiment, the voltage dividing circuit 16
By detecting the voltage between both ends 6a and 6b of the switch circuit 6,
The detected value is given to the CPU 12. The CPU receives the detected value as an input, and inputs the DC input terminal 6a of the switch circuit 6,
An overvoltage switch-on means for turning on the switch circuit 6 to turn on all the switch elements Su to Sw on the lower side of the bridge when the voltage between the switches 6b exceeds the allowable value is realized.

In the above-described electric vehicle, when the regenerative braking is applied in a state where the battery 3 is removed or the terminal of the battery is loosely tightened (a state where the electric contact resistance of the terminal is large), the switch element of the switch circuit 6 is switched. , A high voltage is applied to the switch, and the switch element may be damaged. Therefore, if the overvoltage switch-on means is provided as described above, when the voltage between the DC input terminals of the switch circuit 6 becomes excessive, the armature coil is short-circuited through the switch element on the lower side of the bridge of the switch circuit. As a result, it is possible to prevent an overvoltage from being applied to the switch element, so that it is possible to prevent the switch element from being damaged by the overvoltage. In this case, when an overvoltage is detected by the voltage dividing circuit 16, the display 13 may be operated to display a warning.

One example of a flowchart showing the algorithm of the program executed by the CPU 12 in the embodiment of FIG. 1 is shown in FIGS. FIG. 7 shows a main routine, and FIG. 8 shows a task k of the main routine of FIG. FIG. 9 shows an interrupt routine executed every time the timer measures a predetermined time. FIG. 10 shows that a rising or falling edge of a rectangular wave signal generated by the Hall IC constituting the position detector 2 is detected. The interrupt routine executed every time is shown.

When a power supply voltage is applied from the power supply circuit 21 to the CPU 12, the main routine of FIG. 7 is started. When the main routine is started, first, initial setting of each unit is performed. Next, after reading the accelerator opening degree θth from the accelerator sensor 9, interruption is permitted and a task schedule management program is executed. The task schedule management program is started when a task start request is issued in an interrupt routine shown in FIG. 9 that is executed each time a timer (not shown) measures a predetermined time, and the task 0 is executed at predetermined time intervals. , 1,..., K are executed. In the illustrated example, task 0 is executed first when time t [msec] has elapsed, then task 1 when time 2 t [msec] has elapsed, and task 2 when time 4 t [msec] has elapsed.
Execute Thereafter, tasks 3,... K are sequentially executed at predetermined time intervals, and when task k is completed, the process waits for the next task activation request.

In task 0, first, the accelerator opening θth is read, and the duty ratio DF of the drive current and the control advance angle γ
Is calculated, the end processing of task 0 is performed, and the time until the next task 1 is executed is waited.

In a brushless DC motor, a phase angle (electrical angle) for switching a phase in which a drive current flows is called a control advance angle γ. Generally, the control advance angle γ is a positional relationship between a rotor and a stator. Is set to a more advanced side than the theoretical switching phase angle determined by In a brushless DC motor, the generated torque and the maximum rotation speed change depending on the control advance angle γ, and when the control advance angle γ is set so as to increase the torque, the maximum rotation speed decreases, and the control advance angle γ is advanced. As the maximum number of revolutions increases, the generated torque decreases.

In task 1, first, the voltage Vsw (the voltage between the DC input terminals 6a and 6b) across the switch circuit 6 is read, and it is determined whether or not the voltage Vsw is within a normal range. As a result, the DC input terminals 6a, 6
If the voltage Vsw between b is within the normal range, the task 1
Is performed. If the voltage Vsw between the DC input terminals of the switch circuit 6 is excessive, a flag indicating that the voltage is abnormal is set, a warning is displayed on the display unit 13, and the task 1 is completed.

In task 2, the voltage at both ends of the battery 3 is read, and it is determined whether or not the voltage is within a normal range. If the voltage is normal, the task 2 ends. If the battery voltage is not within the normal range, a flag indicating that the battery is abnormal is set, and a display indicating that the battery voltage is abnormal is displayed.
To end.

Although not shown, the presence or absence of an abnormality in the motor temperature is determined based on the detection value of the temperature sensor 19 for detecting the temperature of the motor, and if abnormal, a flag indicating that the motor temperature is abnormal is set. Alternatively, the presence or absence of an abnormality in the temperature of the switch element is determined from the value detected by the temperature sensor 18 for detecting the temperature of the switch element of the switch circuit 6, and if abnormal, a flag indicating that the temperature of the switch element is abnormal is set. Or other tasks such as determining whether the rotation speed of the electric motor does not exceed a limit value and setting a flag indicating that the speed is excessive when the rotation speed exceeds the limit value are sequentially executed. . In task k, as shown in FIG. 8, the key switch state detection signal Vk obtained from the voltage divider composed of the resistors R10 and R11 is read, and it is determined whether the key switch is in the on state or not. In the case of, the presence or absence of an abnormality in the monitoring target portion is determined. As a result, when there is no abnormality, the drive signal Von is given to the transistor 33 (main relay excitation switch means). Thereby, the transistor 33 is turned on to excite the main relay 5, and the task k is completed. If an abnormality to be monitored is detected while the key switch is on, the transistor 33 is turned off to de-energize the main relay, and a drive signal is supplied to a predetermined one of the transistors 14a to 14c. Thus, the display unit 13 is caused to display a warning indicating that an abnormal state has occurred, and the task k ends. When the key switch is not in the ON state, a flag indicating that the key switch is open is set, and a drive signal is given to a predetermined transistor among the transistors 14a to 14c. The task k is ended with a warning display indicating that the task is open.

The CPU 12 also determines a specific hole I of the holes ICh, Hv, and Hw constituting the position detector 2.
The interrupt routine of FIG. 10 is executed at the rise or fall of the rectangular wave signal generated by C, for example, Hu. In this interrupt routine, first, the time from the time when the previous rising (or falling) of the rectangular wave signal is detected to the time when the current rising or (falling) is detected, and the magnetic pole interval of the rotor of the electric motor are determined. The rotation speed N of the electric motor is detected from the generation interval (mechanical angle) of the rectangular wave signal, and the rotation speed is stored in the RAM. Next, an output pattern indicating whether the output of the three Hall ICHu to Hw provided for each of the three-phase armature coils Au to Aw is H level or L level is stored in the RAM as a Hall IC pattern. Read. As shown in FIGS. 4A to 4C, the patterns of the outputs eu to ew of the Halls ICHu to Hw provided for the U-phase to W-phase armature coils respectively correspond to the rotational angular positions of the rotor. With the change, (1, 0, 1), (1, 0, 0), (1, 1,
0), (0, 1, 0), (0, 1, 1), (0, 0,
1), (1, 0, 1),...

The CPU performs drive processing of the brushless DC motor based on the above-mentioned Hall IC pattern. That is, C
The PU determines the phase to be excited from the above-mentioned Hall IC pattern, and applies the drive current of the duty ratio DF to the armature coil of the phase to be excited at the control lead angle γ determined in Task 0 of the main routine in FIG. Drive instruction signals u 'to w
′ And x ′ to z ′ are generated, and these drive instruction signals are supplied to the switch drive circuit 7B to generate drive signals u to w and x to z from the switch drive circuit. This allows
As shown in FIGS. 4 (D) to (F) and (G) to (I), the switch elements Su to Sw and Sx to Sw are turned on and off, and the drive current is commutated to the armature coils Au to Aw to rotate the rotor. Rotate 1A.

In the main routine of FIG. 7, the process of calculating the control lead angle γ for determining the timing of the commutation of the drive current and the duty ratio DF for determining the average value of the drive current, and the interrupt routine of FIG. A switch control means for controlling the switching element of the switch circuit 6 to turn on and off to realize the adjustment and the commutation of the drive current flowing through the slave coil is realized. Further, in the main routine of FIG. 7, a display control means for controlling the display operation of the display unit 13 is realized by a process of determining whether or not various data are normal and performing a display operation when the data is abnormal. Is done.

Further, the task k of the main routine shown in FIG.
An abnormal state detecting means is realized by the process of judging the presence / absence of the abnormal state (FIG. 8). Turning on the main relay excitation switch means when no abnormality is detected by the means,
A main relay excitation control unit that turns off the main relay excitation switch unit when the abnormality is detected by the abnormal state detection unit is realized.

FIG. 11 shows an example of another configuration of the task 0 executed in the main routine of FIG. In this task 0, it is first determined whether or not a flag indicating abnormality of each unit is set. If the flag indicating abnormality is not set, the accelerator opening θth is read from the accelerator sensor. Although not shown in FIG. 11, after reading the accelerator opening θth, a map calculation is performed on the maximum rotational speed Nth that can be obtained at the accelerator opening θth. Next, the rotation speed N of the motor
Is the maximum rotational speed N that can be obtained with the throttle opening at that time.
The magnitude with th is determined. As a result, when the rotation speed N is lower than the maximum rotation speed Nth, the duty ratio DF and the control advance angle γ of the drive current during the steady operation are map-calculated, and the calculated drive current duty ratio DF and control advance angle γ are calculated. Set γ in the register. If the rotation speed N is higher than the maximum rotation speed Nth, the mode shifts to a mode in which regenerative braking is applied. In this mode, the duty ratio DF of the regenerative charging current flowing during braking is map-calculated, and the calculated duty ratio and the drive instruction signals x ', y' for turning on all the switch elements Sx to Sz on the lower side of the bridge are set. , Z ′ are set in a register for storing the drive instruction signal.

In the routine of FIG. 11, when the flag indicating the abnormality is set as a result of checking the flag, the voltage Vsw between both ends (DC input terminals) 6a and 6b of the switch circuit 6 is changed to the voltage between both ends of the switch element. When the voltage Vsw across the switch circuit is lower than the allowable value compared to the allowable value Va necessary to keep the switch voltage below the withstand voltage, all the switch elements Sx to Sz on the lower side of the bridge of the switch circuit are turned off. The pattern (0, 0, 0) of the drive instruction signal x ', y', z 'for performing the operation is set in a register.

When the voltage Vsw across the switch circuit is higher than the allowable value Va, the drive instruction signals x ', y', z 'for turning on all the switch elements Sx to Sz on the lower side of the bridge are turned on. The pattern (1,1,1) is set in the register.

When the ON pattern or the OFF pattern of the switch elements Sx to Sz is set in the register in the task 0, the pattern set in the register is set in the process of driving the motor in the interrupt routine of FIG. Generates a drive instruction signal.

At the task 0 in FIG. 11, the process of calculating the duty ratio DF at the time of braking and the process of setting the calculated duty ratio and the ON pattern of the switch elements Sx to Sz in the register make the rotation speed N Turns on / off the switch elements Sx to Sz on the lower side of the bridge when the vehicle speed exceeds the maximum rotational speed Nth allowed during flat-land running, and controls the regenerative charging current flowing to the battery by the voltage induced in the armature coils Au to Aw of the motor. Regenerative current control means is realized.

As described above, if the regenerative current control means is provided, when the key switch is opened on a downhill or the like,
When the rotation speed of the electric motor exceeds the maximum rotation speed that can be obtained when traveling on level ground, an appropriate regenerative charging current can be supplied from the armature coils Au to Aw to the battery to prevent the traveling speed of the vehicle from becoming excessive. , Can increase safety.

Also, when the regenerative charging current flows for a long time,
When the armature coil and the switch element of the switch circuit 6 are overheated or the battery 3 is overcharged, the supply of the drive signal to the transistor 33 is stopped.
The contact of the main relay 5 opens and the battery is disconnected from the switch circuit 6. As a result, the regenerative charging current is cut off, so that the motor and the switch circuit can be protected, and overcharging of the battery can be prevented.

In the embodiment shown in FIG. 1, the voltage between the DC input terminals of the switch circuit 6 is input to the DC power supply circuit 30, but the output voltage of the battery 3 is input to the DC power supply circuit 30 through the key switch 4. The voltage between the DC input terminals 6a and 6b of the switch circuit 6 does not necessarily need to be input to the DC power supply circuit 30.

FIG. 2 shows another embodiment of the present invention. In this embodiment, the key switch 4 is
3, the output voltage of the battery 3 is applied to the excitation coil 5b of the main relay through the key switch 4.

In this embodiment, a control unit driving battery 34 is provided to drive the control unit 8, and the output of the battery is input to the power supply circuit 21 of the control unit 8. A voltage between the DC input terminals 6 a and 6 b of the switch circuit 6 is input to the DC power supply circuit 30, and a power supply voltage is applied from the DC power supply circuit 30 to the switch drive circuit 7.

The control unit 8 includes a main relay excitation switch (transistor 3) for turning on / off the excitation current of the main relay.
3), the transistor 33 is turned on when the abnormality is not detected by the abnormal state detecting means, and the transistor 33 is turned on when the abnormal state is detected by the abnormal state detecting means. Is turned off.

Further, in this embodiment, when the key switch 4 is detected to be open, the rotation speed of the motor is zero or equal to or less than a set value (the safety that can be stopped without applying regenerative braking). Speed reduced to a reasonable speed)
The control unit 8 realizes the main relay de-energizing means by turning off the transistor 33 and turning off the main relay (stopping the supply of the drive signal to the transistor 33) when it is detected that Is to be done. Other points are the same as those of the embodiment shown in FIG.

In the embodiment shown in FIG.
When is closed, the exciting current flows from the battery 3 to the exciting coil 5a of the main relay 5 through the key switch 4, and the contact 5b is closed. As a result, the output voltage of the battery is input to the DC power supply circuit 30, and the DC power supply circuit 30 supplies the power supply voltage to the switch drive circuit 7. Battery 34
Since the power is supplied to the CPU through the power supply circuit 21, the control unit 8 is in the operating state even when the key switch is open.

Therefore, in the embodiment shown in FIG. 2, the contact 5b of the main relay 5 can be kept closed even when the key switch is open, and the key switch can be erroneously switched when traveling downhill. When the main relay is opened,
By holding b closed, a regenerative charging current can flow. In addition, when the regenerative charging current flows for a long time, the armature coil or the switch element of the switch circuit is overheated, or when the battery is overcharged, the transistor 33 is turned off. Thus, the electric motor, the switch circuit, and the like can be protected.

When the key switch 4 is closed to start the operation, and when an abnormal state such as overheating of the motor or the switch circuit occurs during the operation, the transistor 33 is turned off and the abnormality is detected. Since the information is displayed on a display such as a lamp or a buzzer, the contacts of the main relay are opened by opening the key switch, thereby protecting the electric motor and the switch circuit.

In the embodiment shown in FIG. 2, a rechargeable battery is used as the battery 34, and as shown by a broken line in FIG.
Preferably, the output of the DC power supply circuit 30 is applied to the battery 34 via a diode 35 or an appropriate charging control circuit (not shown) so that the battery 34 can be charged during traveling.

Next, FIG. 3 shows a hardware configuration of another embodiment of the present invention.
An auxiliary relay 31 having 1a and a normally open contact 31b as a switch means is provided. One end of the exciting coil 31a is connected to the positive terminal of the battery 3, and the other end is connected to the collector of the NPN transistor 32 whose emitter is grounded. One end of the contact 31b is connected to the positive terminal of the battery 3, and the other end is connected to the input terminal 30a of the DC power supply circuit 30 through the diode Do1. The transistor 32 constitutes auxiliary relay excitation switch means for controlling the excitation current of the auxiliary relay 31. When a predetermined condition is satisfied, a drive signal is given from the output port of the CPU 12 to the base thereof, It is turned on. Also, in this example, the voltage across the battery 3 is applied to the DC through the key switch 4 and the diode D4.
-It is input to the DC converter 20 and to the DC power supply circuit 30 via the key switch 4 and the diode Do3. That is, when the key switch 4 is closed, the voltage of the battery is applied to the DC-DC converter 20 and the DC power supply circuit 30 irrespective of the state of the contact 5b of the main relay 5.

In the embodiment shown in FIG. 3, by controlling the auxiliary relay 31 by the CPU 12, when the key switch is opened during traveling, the voltage of the battery is applied to the DC power supply circuit 30 through the contact of the auxiliary relay 31. I am trying to do it. Therefore, in this embodiment, means for controlling the main relay 5 and the auxiliary relay 31 is realized by the CPU 12.

FIG. 12 shows an example of the configuration of the task k of the main routine of FIG. 7 executed to control the main relay 5 and the auxiliary relay 31 in the embodiment of FIG. Reads the key switch state detection signal Vk from the voltage dividing circuit composed of the resistors R10 and R11, and determines whether the key switch 4 is in the ON state. As a result, when the key switch is in the ON state, it is subsequently determined whether or not there is an abnormality in the monitoring target portion. After that, the task k is terminated. If there is an abnormality, the main relay is de-energized, and the abnormal state is displayed, and the task k is terminated.

When it is detected from the key switch state detection signal Vk that the key switch is open, it is determined whether or not there is an abnormality in the monitoring target portion. The voltage Vsw between the DC input terminals of the circuit 6 is compared with the set voltage V1, and if the voltage Vsw is higher than the set voltage V1 (the rotational speed of the motor is considerably high, and the condition for flowing the regenerative charging current is satisfied) If there is, the main relay 5 is excited to end the task k. This allows the regenerative charging current to flow to the battery 3 from the motor side through the switch circuit 6 and the contact 5b of the main relay 5, and the motor is externally supplied as if the key switch was opened while traveling downhill. When the vehicle is driven and the rotational speed may increase, regenerative braking is performed to suppress an increase in vehicle speed.

When the abnormality is detected in the monitored portion while the key switch 4 is determined to be open, the auxiliary relay 31 is excited (by providing a drive signal to the transistor 32) to reduce the voltage of the battery 3. After the power supply of the control unit 8 is secured by supplying the power to the DC power supply circuit 30 through the contact 31b and the diode D03, the main relay 5 is de-energized, and an abnormal state is displayed, and then the task k is terminated.

With this configuration, when the key switch is opened during operation and there is no abnormality in the monitoring target portion, the main relay is excited and the contact 5b is closed, so that the regenerative charging current flows and braking is performed. If an abnormality is detected in the monitored part, the main relay is de-energized and the battery is disconnected from the switch circuit to protect the motor and the switch circuit and prevent overcharging of the battery. Can be. If an abnormality is detected when the key switch is opened, the auxiliary relay is excited to close the contact 31b to secure the power supply of the control unit 8, and the abnormal state is detected by a buzzer or the like. A warning message can be displayed, and the driver can be encouraged to take necessary measures.

In the example of FIG. 12, the voltage between the DC input terminals of the switch circuit 2 is compared with the set voltage to determine whether or not the condition for flowing the regenerative charging current is satisfied. This determination may be made by comparing the rotation speed of the electric motor with a set value.

In the example shown in FIG. 12, when it is detected that the key switch is closed, the presence or absence of an abnormality is determined, and the main relay is energized or de-energized according to the determination result. When the switch is opened, the main relay excitation control means is realized. When it is detected that the key switch is opened, it is determined whether there is any abnormality. When there is no abnormality, the voltage Vsw is compared with V1. When Vsw> V1, the main relay is excited. When the switch is opened, the main relay excitation control means is realized. Further, the auxiliary relay excitation control means is realized by determining whether there is an abnormality when it is detected that the key switch is open, and energizing or de-energizing the auxiliary relay according to the determination result.

While the preferred embodiments of the present invention have been described above, the main ones of the inventions disclosed in this specification will be described below.

(1) A battery, a key switch operated by a driver, a main relay having a contact which closes when excited, a plurality of switch elements connected in a bridge, and anti-parallel connection to both ends of each switch element A switching circuit comprising a diode, wherein the output voltage of the battery is applied through the contacts of the main relay between the DC input terminals, and the output terminal is connected to an armature coil of a brushless DC motor for driving wheels. A switch control means for controlling on / off of a switch element of the switch circuit so as to adjust a magnitude of a drive current flowing through the armature coil and perform commutation, and when the motor is driven from the outside, Regenerative current control means for controlling regenerative charging current flowing from the motor to the battery; Abnormal state detecting means for monitoring the temperature of the switch element, the temperature of the battery and the state of charge of the battery to detect the presence or absence of each abnormality, and display control means for controlling a display for displaying a warning of the abnormal state. An electric vehicle drive control device comprising: a control unit implemented by a CPU; and a switch drive circuit that receives a signal provided from the control unit as an input and provides a drive signal to a switch element of the switch circuit. A DC power supply circuit for supplying a power supply voltage to the control unit and the switch drive circuit when a key switch is closed by being input through a switch, wherein the control unit turns on and off a main relay excitation current for the main relay; When an abnormality switch is provided and no abnormality is detected by the abnormal state detection means It is configured to further realize main relay excitation control means for turning on the main relay excitation switch and for turning off the main relay excitation switch when an abnormality is detected by the abnormal state detection means. An electric vehicle drive control device characterized in that:

(2) The electric vehicle drive control device according to the above item 1, wherein the voltage between the DC input terminals of the switch circuit is input to the DC power supply circuit.

(3) A battery, a key switch operated by a driver, a main relay having a contact that closes when excited, a plurality of bridge-connected switch elements, and anti-parallel connection to both ends of each switch element A switch circuit comprising a diode and an output voltage of the battery being applied through a contact of the main relay between the DC input terminals and an output terminal connected to an armature coil of a brushless DC motor for driving wheels. A switch control means for controlling on / off of a switch element of the switch circuit so as to perform adjustment and commutation of a drive current flowing through the armature coil; and, when the motor is driven from the outside, Regenerative current control means for controlling regenerative charging current flowing from the motor to the battery; Abnormal state detecting means for monitoring the temperature of the switch element, the temperature of the battery and the state of charge of the battery to detect the presence or absence of each abnormality, and display control means for controlling a display for displaying a warning of the abnormal state. An electric vehicle drive control device comprising: a control unit implemented by a CPU; and a switch drive circuit that receives a signal provided from the control unit as an input and provides a drive signal to a switch element of the switch circuit. A DC power supply circuit that supplies a power supply voltage to the switch drive circuit with a voltage between the inputs being provided, and a control unit drive battery that supplies a power supply voltage to the control unit,
The voltage of the battery is applied to the excitation coil of the main relay through the key switch, and the control unit includes a main relay excitation switch for turning on and off an excitation current of the main relay, and the abnormal state detecting means. Main relay excitation control means for turning on the main relay excitation switch when no abnormality is detected, and for turning off the main relay excitation switch when abnormality is detected by the abnormal state detection means. The main relay excitation control switch is turned off when the rotation speed of the motor is detected to be zero or less than the set value while the key switch is detected to be open. And a main relay de-energizing means for setting the main relay to a non-excited state. Control device.

(4) A battery, a key switch operated by the driver, a main relay having a contact that closes when excited, a plurality of bridge-connected switch elements, and anti-parallel connection to both ends of each switch element A switch circuit comprising a diode, and an output voltage of the battery is applied between the DC input terminals through the contacts of the main relay, and the output terminal is connected to an armature coil of a brushless DC motor for driving wheels. A switch control means for controlling on / off of a switch element of the switch circuit so as to perform adjustment and commutation of a drive current flowing through the armature coil; and, when the motor is driven from the outside, Regenerative current control means for controlling regenerative charging current flowing from the motor to the battery; Abnormal state detecting means for monitoring the temperature of the switch element, the temperature of the battery and the state of charge of the battery to detect the presence or absence of each abnormality, and display control means for controlling a display for displaying a warning of the abnormal state. An electric vehicle drive control device comprising: a control unit realized by a CPU; and a switch drive circuit that receives a signal provided from the control unit as an input and provides a drive signal to a switch element of the switch circuit. When a voltage between the DC input terminals of the switch circuit is input to the input terminal while being input to the input terminal through the switch, and the key switch is closed and a voltage appears between the DC input terminals of the switch circuit, A DC power supply circuit for supplying a power supply voltage to the switch drive circuit and the control unit; An auxiliary relay that has a contact connected between the input terminal of the power supply circuit and closes the contact when excited when the battery is excited, and inputs an output voltage of the battery to the DC power supply circuit; Comprises a main relay exciting switch for turning on and off the exciting current of the main relay, and an auxiliary relay exciting switch for turning on and off the exciting current of the auxiliary relay, wherein the key switch is closed and the key switch is closed. A key switch that turns on the main relay excitation switch when the abnormal state detecting means does not detect an abnormality, and turns off the main relay excitation switch when the abnormal state detecting means detects an abnormality. When the main relay excitation control means is closed and the key switch is open and the abnormal state detecting means does not detect an abnormality, When the condition for flowing the regenerative charging current is satisfied, the main relay excitation switch is turned on.When the key switch is open and the abnormal state detecting means detects an abnormality, the main relay excitation switch is turned on. Main switch excitation control means for opening a key switch for turning off a switch; and when the key switch is open and the abnormality detection means does not detect an abnormality, the auxiliary relay excitation switch is turned off. And an auxiliary relay excitation control unit that turns on the auxiliary relay excitation switch when the abnormality detection unit detects an abnormality. Drive control device.

[0122]

As described above, according to the present invention, there is provided a DC power supply circuit for supplying a power supply voltage to a control unit and a switch drive circuit when a battery voltage is input through a key switch and the key switch is closed. Along with
A main relay excitation switch that turns on and off the excitation current of the main relay is provided to control the excitation of the main relay according to the presence or absence of an abnormality. The main relay can be excited. Accordingly, it is possible to prevent the operation from being performed in a state where the abnormality has occurred, and it is possible to enhance safety.

During operation, the main relay can be controlled to be turned on and off while confirming the presence or absence of an abnormal state of the monitoring target portion, so that the monitoring target portion can be properly protected.

In the present invention, when the voltage between the DC input terminals of the switch circuit is input to the DC power supply circuit, the DC power supply circuit is opened even when the key switch is accidentally opened during operation. Since the power supply voltage can be applied to the control unit from above, the control unit can be kept in the operating state, so that a predetermined warning display operation or the like can be performed to ensure safety.

Further, in the present invention, a case is provided in which a DC power supply circuit for supplying a power supply voltage to the switch drive circuit by using a voltage between the DC input terminals of the switch circuit as an input and a control unit drive battery for supplying a power supply voltage to the control unit are provided. In
Even when the key switch is accidentally opened during driving, the main relay can be energized and the regenerative charging current can flow, so not only can the vehicle speed be prevented from excessively increasing and safety can be improved, but also Even when the key switch is opened, the battery can be charged and the traveling distance of the vehicle can be extended.

In the present invention, when an auxiliary relay is provided outside the main relay to control the main relay and the auxiliary relay according to the on / off state of the key switch and the presence or absence of an abnormal state, the key Even when the switch is open, the regenerative charging current can flow or a warning display of an abnormal state can be performed, so that safety can be improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a hardware configuration according to an embodiment of the present invention.

FIG. 2 is a configuration diagram showing a configuration of hardware according to another embodiment of the present invention.

FIG. 3 is a configuration diagram showing a configuration of hardware according to still another embodiment of the present invention.

FIG. 4 is a waveform diagram showing a waveform of a position detection signal output from a position detector and an on / off operation of a switch element of a switch circuit in the brushless DC motor.

FIG. 5 is a circuit diagram showing a configuration of a main part of the embodiment of FIG. 1;

FIG. 6 is a signal waveform diagram when regenerative braking is applied to the electric motor in the embodiment of FIG.

FIG. 7 shows a CPU of a control unit according to the embodiment of the present invention.
Is a flowchart showing an algorithm of a main routine of a program executed by the program.

FIG. 8 is a flowchart showing an example of an algorithm of a task k executed in the main routine of FIG. 7;

FIG. 9 is a flowchart illustrating an algorithm of an interrupt routine executed each time a timer measures a predetermined time in the embodiment of the present invention.

FIG. 10 is a flowchart showing an interrupt routine executed each time a Hall IC provided in the electric motor generates a predetermined signal in the embodiment of the present invention.

FIG. 11 is a flowchart showing another algorithm of task 0 executed in the main routine of FIG. 7;

FIG. 12 is a flowchart illustrating an example of an algorithm of a task k executed in the main routine of FIG. 7 in the embodiment of FIG. 3;

FIG. 13 is a configuration diagram showing a hardware configuration of a conventional electric vehicle drive control device.

[Explanation of symbols]

 Reference Signs List 1 brushless DC motor 2 position detector 3 battery 4 key switch 5 main relay 6 switch circuit 7 switch drive circuit 8 control unit 12 CPU 13 display 30 DC power supply circuit 31 auxiliary relay 32 transistor (auxiliary relay excitation switch) 33 transistor ( Switch for excitation of main relay) Switch element on upper side of Su-Sw bridge Switch element on lower side of Sx-Sz bridge Au-Aw Armature coil

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-7-24012 (JP, A) JP-A-3-222602 (JP, A) JP-A-63-7711 (JP, A) (58) Survey Field (Int.Cl. ⁷ , DB name) B60L 1/00-3/12 B60L ⁷ /00-13/00 B60L 15/00-15/42

Claims (1)

(57) [Claims] A battery and a key operated by a driver.
A switch and a contact having a contact that closes when excited
Relay, bridge-connected switch elements and each
Diodes connected in anti-parallel to both ends of the switch element
Through the contacts of the main relay between the DC input terminals.
The output voltage of the battery
Armature coil of brushless DC motor for wheel drive
To the switch circuit connected to the armature coil
The above-described switch is used to adjust the magnitude of the driving current and perform commutation.
A switch that controls on / off of the switch element of the switch circuit
When the control means and the electric motor are driven from outside
Control the regenerative charging current flowing from the motor to the battery
Regenerative current control means and a predetermined monitoring target
Abnormal state detecting means for detecting the presence or absence of abnormal state and warning of abnormal state
Display control means for controlling a display device for display to the CPU
And a control unit that realizes
And the switch of the switch circuit
A switch driving circuit for supplying a driving signal to the element.
In the moving vehicle drive control device, the voltage of the battery is input to the input terminal through the key switch.
And a DC input terminal of the switch circuit.
The voltage between the terminals is input to the input terminal, and the key switch is closed.
And between the DC input terminals of the switch circuit.
When a voltage appears, the switch drive circuit and the control unit
Connection is between a DC power supply circuit to a preparative give supply voltage, and the input terminal of said battery and a DC power supply circuit
Closed when energized with the contact
Aid for inputting the output voltage of the battery to the DC power supply circuit
A relay, and the control unit turns on and off the exciting current of the main relay.
The main relay excitation switch that switches off and the auxiliary relay
An auxiliary relay excitation switch for turning on and off the magnetic current is provided.
And the key switch is closed
When the abnormal state detecting means has not detected an abnormality,
Turn on the main relay excitation switch, and
When the state detection means detects an abnormality, the main relay
Key switch that turns off the magnetic switch.
-Excitation control means and the key switch is open and the
When the abnormal state detecting means has not detected an abnormality,
The condition passing a regenerative charging current from the moving machine to the battery is satisfied
The main relay excitation switch to the ON state when
When the key switch is open and the abnormal state detecting
When the stage detects an abnormality, the main relay excitation switch
Turn off the key switch.
Magnetic control means and the key switch is open and the abnormal
When the detecting means has not detected any abnormality, the auxiliary relay
-Turn off the excitation switch and turn off the key switch.
When it is open and the abnormality detection means detects an abnormality
The auxiliary relay excitation switch is turned on.
And auxiliary relay excitation control means.
An electric vehicle drive control device, comprising: