JP6354466B2 - Motor controller for vehicle air conditioner - Google Patents

Description

  The present invention relates to a motor control device for a vehicle air conditioner.

  A circuit for controlling the driving of a blower motor (hereinafter abbreviated as “motor”), which is a motor for a vehicle air conditioner, is mounted with a semiconductor such as an FET (field effect transistor) as a switching element. These semiconductors such as FETs may be damaged when the temperature exceeds a predetermined temperature.

  In order to prevent damage to semiconductors such as FETs, when the circuit overheats, the rotation of the motor is temporarily stopped. However, when the motor is stopped, the vehicle air conditioner also stops. Therefore, the comfort in the passenger compartment is impaired. Further, when the motor is stopped, the blowing of air to the circuit due to the rotation of the motor is also stopped, so that it takes time to cool the overheated circuit and there is a problem that the reactivation of the vehicle air conditioner is delayed.

  Patent Document 1 discloses an invention of a power transistor overheating prevention device for an automotive air conditioner that eliminates an overheating state by temporarily reducing the rotation of the motor without stopping the motor even if the circuit overheats. Yes.

JP-A-8-204076

  However, the power transistor overheat prevention device for an automotive air conditioner described in Patent Document 1 is configured to reduce the voltage applied to the motor so that the rotational speed before the overheat state is reached when the overheat state of the circuit is resolved. I have control. As a result, the rotational speed of the motor, which has been temporarily reduced, suddenly accelerates and returns to the rotational speed before the reduction, which gives the user a feeling of strangeness.

  FIG. 5 is a schematic diagram showing an example of changes in the target rotation speed 90 and the actual rotation speed 92 that is the actual rotation speed in the rotation control of the motor that has become overheated. In FIG. 5, the motor or the circuit for controlling the drive of the motor is in an overheated state at time t1, so that the predetermined rotational speed is reduced until the overheated state is eliminated by reducing the rotational speed of the motor to the predetermined speed by time t2. To keep rotating at the speed of.

  When the overheat state is resolved at time t3 in FIG. 5, the motor rotational speed is returned to the target rotational speed 90. However, since the deviation between the target rotational speed 90 and the actual rotational speed 92 at time t3 is large, the rotational speed of the motor The control for rapidly increasing the value is executed. As a result, the actual rotation speed 92 of the motor reaches the target rotation speed 90 at time t4, but a sudden increase in the rotation speed gives the user a sense of incongruity. In addition, a sudden increase in rotational speed may impair the stability of the rotational speed of the motor, and the rotational speed of the motor varies in small increments as seen in the change in the actual rotational speed 92 after time t4 in FIG. In some cases, a phenomenon called ripple occurs.

  The present invention has been made in view of the above, and an object of the present invention is to provide a motor controller for a vehicle air conditioner that restores the reduced rotational speed of the motor without a sense of incongruity.

In order to solve the above-mentioned problem, a motor controller for a vehicle air conditioner according to claim 1 is a physical quantity detection unit that detects a physical quantity indicating a load of the motor, a drive unit that drives the motor, and an actual rotational speed of the motor. When the physical quantity detected by the physical quantity detection unit at the time of starting the motor is less than a threshold value, the rotational speed of the motor is stopped based on the command target rotational speed indicated by the command value. When the physical quantity detected by the physical quantity detection unit is equal to or higher than the threshold value after starting up the motor and rotating at the command target rotational speed after increasing from the state to the command target rotational speed and rotating at the command target rotational speed. , the rotational speed of the motor is reduced to a predetermined rotational speed lower than the command target rotational speed, and after the rotational speed of the motor is decreased, the physical amount detected by the physical quantity detection unit the Set the actual rotational speed of the motor to the rotational speed detection unit detects when it becomes less than the value in the provisional target rotational speed, sequentially adds a predetermined speed operation amount to the provisional target speed every predetermined execution timing And gradually increasing the temporary target rotational speed to the command target rotational speed, and the drive unit so that the actual rotational speed of the motor becomes the temporary target rotational speed gradually increasing to the command target rotational speed. And a control unit attached to the motor for controlling the motor .

This vehicle air conditioner motor control device gradually increases the actual rotation speed of the motor, which has been decreased when the physical quantity indicating the load of the motor exceeds a threshold value, to a command value, thereby making the sense of incongruity of the decreased motor rotation speed. Can be restored without any problems.

The motor controller for a vehicle air conditioner according to claim 2 is the motor controller for a vehicle air conditioner according to claim 1 , wherein the physical quantity includes a temperature of the motor or a circuit of the motor, a current of the driving unit, and a power supply voltage. One of them.

  According to this vehicle air conditioner motor control device, it is possible to determine the motor load based on temperature, current, or voltage that is easy to detect.

It is the schematic which shows the structure of the motor unit using the motor control apparatus for vehicle air conditioners which concerns on embodiment of this invention. It is a figure which shows the outline of the motor control apparatus for vehicle air conditioners which concerns on embodiment of this invention. An example of each change of the target rotational speed, the actual rotational speed that is the actual rotational speed, and the command value in the rotational control of the motor after the failure detection in the motor controller for the vehicle air conditioner according to the embodiment of the present invention is shown. FIG. It is a flowchart which shows an example of the target rotational speed calculation process of the motor control apparatus for vehicle air conditioners which concerns on embodiment of this invention. It is the schematic which showed an example of each change of the actual rotational speed which is the target rotational speed and the actual rotational speed in rotation control of the motor which became the overheated state.

  FIG. 1 is a schematic diagram showing a configuration of a motor unit 10 using a vehicle air conditioner motor control device 20 according to the present embodiment. The motor unit 10 according to the present embodiment in FIG. 1 is a so-called blower motor unit used for blowing air from an in-vehicle air conditioner as an example.

  The motor unit 10 according to the present embodiment relates to a three-phase motor having an outer rotor structure in which a rotor 12 is provided outside a stator 14. The stator 14 is an electromagnet in which a lead wire is wound around a core member, and constitutes three phases of a U phase, a V phase, and a W phase. Each of the U-phase, V-phase, and W-phase of the stator 14 generates a so-called rotating magnetic field by switching the polarity of the magnetic field generated by the electromagnet under the control of the vehicle air conditioner motor control device 20 described later.

  A rotor magnet is provided inside the rotor 12 (not shown), and the rotor magnet rotates the rotor 12 by responding to the rotating magnetic field generated by the stator 14. The rotor 12 is provided with a shaft 16 and rotates integrally with the rotor 12. Although not shown in FIG. 1, in this embodiment, the shaft 16 is provided with a multi-blade fan such as a so-called sirocco fan, and the multi-blade fan rotates together with the shaft 16 so that air can be blown in the vehicle-mounted air conditioner. It becomes.

  The stator 14 is attached to the vehicle air conditioner motor control device 20 via the upper case 18. The vehicle air conditioner motor control device 20 includes a substrate 22 of the vehicle air conditioner motor control device 20 and a heat sink 24 that dissipates heat generated from elements on the substrate 22. A lower case 60 is attached to the motor unit 10 including the rotor 12, the stator 14, and the vehicle air conditioner motor control device 20.

  FIG. 2 is a diagram schematically showing the vehicle air conditioner motor control device 20 according to the present embodiment. The inverter circuit 40 switches power supplied to the coil of the stator 14 of the motor 52. For example, the inverter FETs 44A and 44D switch the power supplied to the U-phase coil 14U, the inverter FETs 44B and 44E switch to the V-phase coil 14V, and the inverter FETs 44C and 44F switch the power supplied to the W-phase coil 14W.

  The drains of the inverter FETs 44A, 44B, and 44C are connected to the positive electrode of the on-vehicle battery 80 through a noise removing choke coil 46. The sources of the inverters FET 44D, 44E, and 44F are connected to the negative electrode of the battery 80 through the reverse connection prevention FET 48.

  In the present embodiment, the Hall element 12B detects the magnetic field of the rotor magnet 12A or the sensor magnet provided coaxially with the shaft 16. The microcomputer 32 detects the rotational speed and position (rotational position) of the rotor 12 based on the magnetic field detected by the Hall element 12B, and controls switching of the inverter circuit 40 according to the rotational speed and rotational position of the rotor 12. .

  The microcomputer 32 receives a control signal including a command value related to the rotational speed of the rotor 12 from the air conditioner ECU 82 that controls the air conditioner in response to the switch operation of the air conditioner. The microcomputer 32 is connected to a voltage dividing circuit 54 constituted by a thermistor 54A and a resistor 54B, and a current sensor 56 provided between the inverter circuit 40 and the negative electrode of the battery 80.

  Since the resistance value of the thermistor 54 </ b> A constituting the voltage dividing circuit 54 changes according to the temperature of the circuit board 22, the voltage of the signal output from the voltage dividing circuit 54 changes according to the temperature of the circuit board 22. The microcomputer 32 calculates the temperature of the substrate 22 based on the change in the voltage of the signal output from the voltage dividing circuit 54. In the present embodiment, for convenience, the signal output from the voltage dividing circuit 54 is a signal based on the detection result of the thermistor 54A. In the present embodiment, the temperature of the circuit board 22 calculated based on the detection result of the thermistor 54A is set as the temperature of the circuit board 22 detected by the thermistor 54A.

  The current sensor 56 includes, for example, a shunt resistor 56A and an amplifier 56B that amplifies the potential difference between both ends of the shunt resistor 56A. The microcomputer 32 calculates the current of the inverter circuit 40 based on the signal output from the amplifier 56B.

  In the present embodiment, the signal from the thermistor 54A, the signal output from the current sensor 56, and the signal output from the Hall element 12B are input to the temperature protection control unit 62 in the microcomputer 32. The temperature protection control unit 62 calculates the element temperature of the substrate 22, the current of the inverter circuit 40, the rotational speed of the rotor 12, and the like based on the input signals. The temperature protection control unit 62 is connected to a battery 80 as a power source, and the temperature protection control unit 62 detects the voltage of the battery 80 as a power supply voltage.

  A control signal from the air conditioner ECU 82 is input to the speed control unit 64 in the microcomputer 32. The speed controller 64 also receives a signal output from the Hall element 12B. The speed control unit 64 performs PWM (Pulse Width Modulation) control related to switching control of the inverter circuit 40 based on the rotational speed and rotational position of the rotor 12 based on the control signal from the air conditioner ECU 82 and the signal from the hall element 12B. Calculate the duty ratio.

  A signal indicating the duty ratio calculated by the speed control unit 64 is input to the PWM output unit 66 and the temperature protection control unit 62. The temperature protection control unit 62 corrects the duty ratio calculated by the speed control unit 64 based on the temperature of the substrate 22, the rotational speed of the rotor 12, and the load on the circuit of the motor control device 20 for the vehicle air conditioner, thereby controlling the speed. This is fed back to the unit 64. The load of the circuit is, for example, the current of the inverter circuit 40, the power supply voltage, and the duty ratio of the voltage generated by the PWM output unit 66 in the inverter circuit 40 and applied to the motor 52. In the present embodiment, as an example, the current of the inverter circuit 40, the power supply voltage, and the temperature of the substrate 22 are set as physical quantities indicating a load. In the present embodiment, the load of the motor 52 and the load of the circuit of the vehicle air conditioner motor control device 20 are collectively referred to as a motor load.

  When the temperature of the circuit board 22 is equal to or higher than a predetermined temperature threshold, the current of the inverter circuit 40 is equal to or higher than the predetermined current threshold, and the power supply voltage is equal to or higher than the predetermined power supply voltage threshold. It is determined that a failure has been detected in the motor 52 or the circuit. When a failure is detected, the temperature protection control unit 62 corrects the duty ratio calculated by the speed control unit 64 so as to reduce the rotation speed of the motor 52 and feeds back to the speed control unit 64. The predetermined temperature threshold, the predetermined current threshold, and the predetermined power supply voltage threshold vary depending on the specifications of the motor 52 and the vehicle air conditioner motor control device 20, and are specifically described through a simulation using a computer and an experiment using an actual device. decide.

  A memory 68 that is a storage device is connected to the temperature protection control unit 62. The memory 68 stores the predetermined temperature threshold value, the predetermined current threshold value, the predetermined power supply voltage threshold value, a duty ratio correction value for reducing the rotational speed of the motor 52 when a failure is detected, and the like.

  The speed control unit 64 feeds back the correction by the temperature protection control unit 62 to the duty ratio calculated by itself by, for example, PI control, and outputs a signal indicating the duty ratio obtained by the feedback to the PWM output unit 66. The PWM output unit 66 controls switching of the inverter circuit 40 so as to generate a voltage having a duty ratio indicated by the input signal.

  Then, the effect | action and effect of the motor control apparatus 20 for vehicle air conditioners which concern on this Embodiment are demonstrated. FIG. 3 shows each of the target rotational speed 94, the actual rotational speed 96 that is the actual rotational speed, and the command value 98 in the rotational control of the motor 52 after failure detection in the vehicle air conditioner motor control apparatus 20 according to the present embodiment. It is the schematic which showed an example of the change of.

  The target rotational speed 94 is a command target rotational speed 94A that is the same as the command value 98 of the control signal input from the air conditioner ECU 82 until time t1 in FIG. Until time t1, the duty ratio of the voltage applied to the motor 52 is controlled so that the actual rotational speed 96 becomes the command target rotational speed 94A.

  When a failure is detected, for example, when the temperature of the circuit board 22 exceeds the temperature threshold at time t1 in FIG. 3, the temperature protection control unit 62 of the microcomputer 32 corrects the failure detection stored in the memory 68. Based on the value, the duty ratio calculated by the speed control unit 64 is corrected and fed back to the speed control unit 64. As a result, the actual rotational speed 96 of the motor 52 decreases from S1 to S2 by time t2. Specific numerical values of S1 and S2 vary depending on the specifications of the motor 52 and the vehicle air conditioner motor control device 20, but as an example, S1 is 4000 rpm and S2 is 1000 rpm. The manner in which the actual rotational speed 96 decreases from S1 to S2 is based on the correction value stored in the memory 68. In the case where the correction value rapidly decreases the duty ratio after the failure is detected, the actual rotational speed of the motor 52 changes from S1 to S2 in a short time. If the correction value slowly decreases the duty ratio after the failure is detected, the actual rotational speed 96 of the motor 52 gradually decreases from S1 to S2.

  In FIG. 3, after time t 1, the command value 98 is the same as before time t 1, but the target rotational speed 94 decreases with the actual rotational speed 96. In the present embodiment, when a failure is detected, the target rotational speed 94 is not the same as the command value 98, but is set to a temporary target rotational speed 94B that matches the reduced actual rotational speed 96. Specifically, the speed control unit 64 sets the actual rotational speed 96 as the target rotational speed 94 instead of the command value 98 when a failure is detected. That is, the temporary rotational speed 94B is calculated by substituting the actual rotational speed 96 into the target rotational speed 94.

  From time t1 to time t3 in FIG. 3 is an assignment period 100 in which the actual rotational speed 96 is substituted for the target rotational speed 94 to calculate the provisional target rotational speed 94B. The substitution period 100 is continued until time t3 when a physical quantity indicating a load such as the temperature of the circuit board 22 of the circuit is less than a predetermined threshold, for example, so that no failure is detected.

  3 is a return period 102 in which the actual rotational speed 96 of the motor 52 is increased to the command value 98. In the return period 102, the actual rotational speed 96 of the motor 52 is gradually increased to the command value 98 at a predetermined acceleration similar to the case where the motor 52 is started, and the temporary target gradually increased. The rotational speed of the motor 52 is accelerated from S2 to S1 according to the rotational speed 94B. Specifically, a speed operation amount (hereinafter abbreviated as “speed operation amount”) at each execution timing when calculating the target rotational speed is sequentially added to the current temporary target rotational speed 94B to obtain a new temporary target. The rotational speed 94B is calculated sequentially. Then, the duty ratio is controlled so that the rotational speed of the motor 52 gradually increases in accordance with the provisional target rotational speed 94B calculated sequentially and becomes S1, which is the rotational speed indicated by the command value 98, at time t4.

  The speed operation amount described above is, for example, a speed change amount that can be changed at each execution timing of the calculation process in the calculation process of the target rotation speed when the rotation speed of the motor 52 is increased from 0 rpm to the rotation speed indicated by the command value. The upper limit value is stored in the memory 68 in the present embodiment.

  FIG. 4 is a flowchart showing an example of target rotational speed calculation processing of the vehicle air conditioner motor control device 20 according to the present embodiment. When the vehicle air conditioner starts operating due to the switch-on, in step 400, the command value from the air conditioner ECU 82 and the rotation speed of the motor 52 detected by the hall element 12B are captured.

  In step 402, it is determined based on the acquired rotational speed whether the motor 52 is started from a stopped state, that is, whether the motor 52 is in a starting stage or a stage where the rotation is stable after starting.

  If it is determined in step 402 that the engine has been started, in step 416, the actual rotational speed is increased to a command target rotational speed that is a target rotational speed indicated by the command value at a predetermined acceleration. In the acceleration at the time of starting the motor 52 in step 416, the provisional target rotation speed obtained by adding the aforementioned speed operation amount to the rotation speed 0 is set so that the actual rotation speed of the motor 52 becomes the provisional target rotation speed. Control. Furthermore, a new temporary target rotational speed is calculated by adding the speed operation amount to the temporary target rotational speed, the actual rotational speed is adjusted to the new target rotational speed, and thereafter, until the temporary target rotational speed reaches the command target rotational speed. Then, the calculation of the new temporary target rotational speed and the control for adjusting the actual rotational speed to the new temporary target rotational speed are continued.

  In step 416, when the provisional target rotational speed has approximated the command target rotational speed, the smooth rotation of the motor 52 is controlled by setting the target rotational speed of the motor 52 by the following control. . For example, when the command target rotation speed is compared with the provisional target rotation speed and the command target rotation speed and the provisional target rotation speed match, the command target rotation speed is set as the target rotation speed. The rotational speed of the motor 52 is controlled. Further, when the command target rotation speed is larger than the temporary target rotation speed, a new temporary target rotation speed is calculated by adding the aforementioned speed operation amount to the temporary target rotation speed. When the command target rotational speed is smaller than the temporary target rotational speed, the target rotational speed is adjusted by subtracting the speed operation amount from the temporary target rotational speed to calculate a new temporary target rotational speed.

  If the rotation of the motor 52 is stable after startup, an affirmative determination is made in step 402, and the presence or absence of failure detection is determined in step 404. The presence / absence of failure detection is determined, for example, by whether or not the temperature of the circuit board 22 has reached or exceeded a predetermined temperature threshold.

  If it is determined in step 404 that, for example, the temperature of the substrate 22 is equal to or higher than a predetermined temperature threshold value and a failure is detected, the actual rotational speed of the motor 52 is decreased to a predetermined rotational speed S2 in step 406. In step 406, the provisional target rotational speed after deceleration is calculated by substituting the actual rotational speed 96 into the target rotational speed 94 as in the substitution period 100 from time t1 to time t3 in FIG. In step 408, the predetermined rotational speed S2 is maintained.

  In step 410, it is determined whether or not the failure has been resolved. The failure elimination is determined, for example, based on whether or not the temperature of the circuit board 22 is below a predetermined temperature threshold. If it is determined in step 410 that the failure has not been resolved, the procedure returns to step 408 to maintain the rotational speed of the motor 52 at the predetermined rotational speed S2.

  If it is determined in step 410 that the failure has been eliminated, in step 412, the actual rotational speed is increased from the predetermined rotational speed S2 to the command target rotational speed at the same predetermined acceleration as when the motor 52 is started. In step 410, the actual rotational speed reduced to the predetermined rotational speed S2 is set as the temporary target rotational speed, the above-mentioned speed operation amount is added to the temporary target rotational speed, and a new temporary target rotational speed is calculated. This is done by adjusting the rotation speed to the calculated temporary target rotation speed. Thereafter, as in the case of step 416, calculation of a new temporary target rotational speed and control for adjusting the actual rotational speed to the new temporary target rotational speed are continued until the temporary target rotational speed reaches the command target rotational speed.

  If the temporary target rotational speed has approximated the command target rotational speed, the command target rotational speed is compared with the temporary target rotational speed in the same manner as in step 416, and the command target rotational speed matches the temporary target rotational speed. In order to do so, the command target rotational speed is set as the target rotational speed. In addition, when the command target rotation speed is larger than the provisional target rotation speed, a new provisional target rotation speed is calculated by adding the aforementioned speed operation amount to the provisional target rotation speed, and the command target rotation speed is higher than the provisional target rotation speed. When the speed is low, the target rotational speed is adjusted by subtracting the speed operation amount from the temporary target rotational speed to calculate a new temporary target rotational speed.

  In step 414, it is determined whether or not the switch of the vehicle air conditioner is turned off. If the switch is turned off, the process is terminated. If it is determined in step 414 that the switch is not turned off, the procedure returns to step 400 and the series of procedures is executed again.

  As described above, in the present embodiment, when the rotational speed of the motor 52 is decreased after the failure is detected, the target rotational speed is adjusted to the actual rotational speed and the target rotational speed is adjusted to the actual rotational speed. The speed is gradually improved. As a result, the actual rotational speed can be gradually improved up to the rotational speed indicated by the command value, and the reduced rotational speed of the motor can be restored without a sense of incongruity.

  Further, in the present embodiment, at the time of fail recovery for returning the reduced rotational speed to the rotational speed indicated by the command value, the rotational speed is improved at the same pace as when the motor 52 is started. As a result, the procedure at the time of starting the motor can be used at the time of fail return, and there is an effect that a special program for improving the rotation speed at the time of fail return is not required.

DESCRIPTION OF SYMBOLS 10 ... Motor unit, 12 ... Rotor, 12A ... Rotor magnet, 12B ... Hall element, 14 ... Stator, 14U, 14V, 14W ... Coil, 16 ... Shaft, 18 ... Upper case, 20 ... Motor control apparatus for vehicle air conditioners, 22 ... Substrate, 24 ... Heat sink, 32 ... Microcomputer, 40 ... Inverter circuit, 44A, 44B, 44C, 44D, 44E, 44F ... Inverter FET, 46 ... Choke coil, 48 ... Reverse connection prevention FET, 52 ... Motor, 54 ... Minute Pressure circuit, 54A ... thermistor, 54B ... resistor, 56 ... current sensor, 56A ... shunt resistor, 56B ... amplifier, 60 ... lower case, 62 ... temperature protection control unit, 64 ... speed control unit, 66 ... PWM output unit, 68 ... Memory, 80 ... Battery, 82 ... Air-conditioner ECU, 90 ... Target rotational speed, 92 ... Actual rotational speed, 94 Target rotational speed, 94A ... command target rotational speed, 94B ... provisional target rotational speed, 96 ... actual rotational speed, 98 ... command value, 100 ... assignment period, 102 ... return interval

Claims (2)

A physical quantity detection unit for detecting a physical quantity indicating a load of the motor;
A drive unit for driving the motor;
A rotational speed detector for detecting an actual rotational speed of the motor;
When the physical quantity detected by the physical quantity detection unit at the time of starting the motor is less than the threshold value, based on the command target rotation speed indicated by the command value, the rotation speed of the motor from the stop state to the command target rotation speed in advance. When the physical quantity detected by the physical quantity detection unit becomes equal to or higher than the threshold after starting up the motor and rotating at the command target rotational speed and rotating at the command target rotational speed, the rotational speed of the motor is set to the command is lower than the target rotational speed to a lower predetermined rotational speed, and after the rotational speed of the motor is decreased, the rotational speed detection portion when the physical quantity detected by the physical amount detecting unit is less than the threshold value detects the The actual rotational speed of the motor is set as the temporary target rotational speed, and a predetermined speed operation amount is sequentially added to the temporary target rotational speed at each predetermined execution timing to obtain the temporary target rotational speed. With gradually increased to decree target rotational speed, the actual rotational speed of the motor, attached to the motor for controlling the command target rotational speed the drive unit so as to gradually become the tentative target rotation speed is increased to A control unit;
A motor control device for a vehicle air conditioner. The physical quantity is the motor or the temperature of the circuit of the motor, the vehicle air conditioner for motor control apparatus according to claim 1, wherein any one of the current and supply voltage of the drive unit.

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