JP7275833B2 - Motor controller and electric pump - Google Patents

Description

The present invention relates to a motor control device for controlling the drive of a three-phase motor by switching the energized state of coils of the three-phase motor, and to an electric pump controlled by the three-phase motor driven and controlled by such a motor control device. .

Conventionally, there is a technology that detects the rotation of the rotor of a three-phase motor without using a rotation sensor while driving the three-phase brushless motor (hereinafter referred to as "three-phase motor") and energizes the coils of the three-phase motor. have been utilized (eg, US Pat.

Patent Document 1 describes a control circuit for a sensorless motor (hereinafter referred to as "control circuit"). This control circuit is configured to, when energizing one of the three coils of the three-phase motor, prohibit energization of the other coil for a predetermined time. Further, the time (predetermined time) during which such energization is prohibited is configured to be switched depending on whether the three-phase motor is in steady operation or when the three-phase motor is started.

JP-A-2-276493

Here, the terminal voltage of the coil of the non-energized phase (non-energized phase) among the coils of the three-phase motor has spike noise (hereafter referred to as "spike noise") when switching from the energized state to the non-energized state. ) is known to occur. It is also known that this spike noise causes erroneous detection when the rotation of the rotor is detected without using the rotation sensor described above. Such erroneous detection causes locking of the three-phase motor and loss of synchronism. The technology described in Patent Literature 1 has not been studied to prevent such erroneous detection, and there is room for improvement.

Therefore, a motor control device that can appropriately drive and control a three-phase motor, and an electric pump that is driven by the three-phase motor controlled by such a motor control device are required.

A characteristic configuration of a motor control device according to the present invention is a motor control device that performs drive control of the three-phase motor by switching energization states of coils of the three-phase motor, wherein two of the three-phase coils are In the state where the coil of is energized, the voltage value of the phase voltage of one phase different from the two phases is connected to each of the three terminals of the three-phase motor via a resistor. A timing when the voltage value of the voltage exceeds a connection point voltage value and a timing when the voltage value of the phase voltage falls below the connection point voltage value are detected as first zero crosses, and the first zero crossing is detected when the phase voltage exceeds the connection point voltage value. If the timing exceeds the voltage value, the timing at which the phase voltage having a voltage value lower than the connection point voltage value is detected for the first time after the lapse of a predetermined time is detected as a second zero cross, and the first zero cross is detected as the phase voltage. Zero-cross detection for detecting, as a second zero cross, the timing at which the phase voltage having a voltage value higher than the connection point voltage value is detected for the first time after the lapse of the predetermined time when the voltage falls below the connection point voltage value. a first counting unit that counts a first time that is the time from the first zero crossing to the second zero crossing; and after counting the first time by the first counting unit, at the first time a second counting unit for counting a period until a second time set as a time shorter than the first time elapses based on the first counting unit; after the first time is counted by the first counting unit, the first time a third counting unit that is set as a time shorter than the first time based on and counts a period until a third time used as the predetermined time elapses, and the third counting unit counts the third time a mask period setting unit that sets the counting period as a mask period in which the first zero cross and the second zero cross can be detected and the position of the rotor of the three-phase motor is not detected; , after the end of the mask period, until the next first zero crossing is detected, a detection unit for detecting the position of the rotor based on the current flowing through the coil; and the detected position of the rotor . a control unit for switching the energization state of the coil based on the counting result of the second counting unit; and the second zero cross detected by the zero cross detecting unit is newly detected after the second zero cross is detected. and a determining unit that determines whether the second zero crossing is appropriate based on the first zero crossing, and the second counting unit and the third counting unit when the determining unit determines that the second zero crossing is not appropriate. is the time used as the first time, and the first time immediately before the detection of the first zero cross, which is the basis of the first time until the second zero cross determined to be inappropriate. counting is started after counting the time until the magnitude relationship between the voltage value of the second phase voltage and the connection point voltage value after counting the third time is counted as a preliminary first time and a counting unit.

In sensorless motor control, if the time between two zero crossings cannot be calculated accurately, the motor drive cannot be properly controlled. Therefore, with the above characteristic configuration, when it is determined that the second zero crossing detected by the zero crossing detection unit is not appropriate, the counting result of the first time by the first counting unit is not appropriate, so the first counting The second time and the third time are set using the first preliminary time by the preliminary counting unit instead of the first time by the unit, and the driving of the three-phase motor is controlled based on these second time and third time. be able to. Therefore, step-out of the three-phase motor can be prevented, and it is possible to drive and control the three-phase motor appropriately under various driving conditions.

Further, the determination unit determines the new first time by the time the counting result of the second counting unit becomes equal to the second time or by the time the counting result of the third counting unit becomes equal to the third time. If a zero cross is detected, it is preferable to determine that the immediately preceding second zero cross is inappropriate.

With such a configuration, it can be easily determined whether or not the second zero crossing is appropriate. Therefore, when it is determined that the second zero crossing is not appropriate, the preliminary first time by the preliminary counting unit can be quickly used as the first time. Therefore, it is possible to appropriately control the drive of the three-phase motor.

Moreover, it is preferable that the determination unit determines that the second zero cross is not appropriate when the first zero cross is not detected at the timing when the second zero cross is detected.

With such a configuration, when the second zero cross is detected, it can be easily determined whether or not the second zero cross is appropriate. Therefore, when it is determined that the second zero crossing is not appropriate, the preliminary first time by the preliminary counting unit can be used more quickly as the first time. Therefore, it is possible to appropriately control the drive of the three-phase motor.

Further, the preliminary counting unit includes: a first preliminary counting unit that starts counting when the phase voltage having a voltage value lower than the connection point voltage value exceeds the connection point voltage value; It is preferable to have a second pre-counter which starts counting when said phase voltage of high voltage value falls below said node voltage value.

With such a configuration, the first preliminary counting section and the second preliminary counting section alternately start counting the preliminary first time each time the first zero crossing is detected. It can be used whenever necessary.

Further, the electric pump according to the present invention is characterized in that it is driven by the three-phase motor controlled by the motor control device.

With such a characteristic configuration, for example, when the electric pump is a water pump, the motor control device can be operated appropriately even when the amount of gas present in the fluid suddenly decreases and the load suddenly increases. It becomes possible to drive and control a three-phase motor. Further, for example, when the electric pump is an oil pump, the motor control device can appropriately drive and control the three-phase motor even when the viscosity of the fluid suddenly increases and the load suddenly increases. . Such an electric pump can be installed, for example, in an electric vehicle that is operated under severe conditions, thereby improving usability.

It is a figure which shows the structure of a motor control apparatus. It is a figure which shows various counting results.

The motor control device according to the present invention drives the three-phase motor while detecting the position of the rotor of the three-phase motor without a so-called sensor. The three-phase motor can be appropriately driven regardless of the surge that occurs when The motor control device 1 of this embodiment will be described below.

FIG. 1 is a diagram schematically showing a motor control device 1 of this embodiment. The motor control device 1 performs drive control of the three-phase motor M by switching the energized state of the coils C of the three-phase motor M. FIG. The coils C of the three-phase motor M are stator coils connected by so-called star connection or delta connection. In the example of FIG. 1, a three-phase motor M has three coils C connected in a delta connection. The drive control of the three-phase motor M refers to controlling the rotor (not shown) of the three-phase motor M to rotate and output rotational force. The motor control device 1 controls the driving of the three-phase motor M as described above. In this embodiment, as described above, the coils C of the three-phase motor M are described as being configured by delta connection, but they may be configured by star connection.

As shown in FIG. 1, the motor control device 1 of this embodiment includes a control section 10, a driver 20, an inverter 30, a comparison section 40, a zero cross detection section 42, a first counting section 51, a second counting section 52, a 3 counting section 53, mask period setting section 60, detecting section 61, determining section 62, and pre-counting section 70. These functional sections perform processing related to drive control of the three-phase motor M described above. In order to do this, it is built with hardware or software, or both, with a CPU as a core component.

The control unit 10 switches the energization state of the coil C based on the position of the rotor detected by the detection unit 61 (described later) and the count result of the second counting unit 52 (described later). The position of the rotor is the position (rotational angle) of the rotor (not shown) that rotates according to the energization of the coils C of the three-phase motor M. The counting result of the second counting unit 52 is the counting result of the second counting unit 52 that counts the timing of switching the energized state of the coil C. FIG. Switching the energization state of the coil C means a state in which a current flows from the U-phase coil C to the V-phase coil C, a state in which a current flows from the U-phase coil C to the W-phase coil C, and a state in which the current flows from the V-phase coil C. Current flowing through W-phase coil C, current flowing from V-phase coil C to U-phase coil C, current flowing from W-phase coil C to U-phase coil C, W-phase coil C to a state in which a current flows through the coil C of the V phase. The control unit 10 generates a PWM signal and PWM-controls an inverter 30, which will be described later. This makes it possible to control the energization of the coils C of the three-phase motor M. FIG. Since PWM control using such a PWM signal is well known, the description thereof will be omitted. Here, in the present embodiment, an example in which the motor control device 1 performs so-called 120-degree energization control will be described. can be

Driver 20 is provided between controller 10 and inverter 30 and receives a PWM signal generated by controller 10 . The driver 20 improves the drivability of the input PWM signal and outputs it to the inverter 30 .

The inverter 30 drives the three-phase motor M by controlling the current flowing through the coils C of the three-phase motor M. As shown in FIG. Further, the inverter 30 is a high-side switching element connected in series between the first power supply line 2 and the second power supply line 3 connected to a potential lower than the potential of the first power supply line 2. Three sets of arm portions A each having QH and a low-side switching element QL are provided. The first power supply line 2 is a cable connected to the power supply V. As shown in FIG. The second power supply line 3 connected to a potential lower than the potential of the first power supply line 2 is a cable to which a potential lower than the output voltage of the power supply V is applied, and is a grounded cable in this embodiment. corresponds to

In this embodiment, the high-side switching element QH is constructed using a P-MOSFET, and the low-side switching element QL is constructed using an N-MOSFET. The high-side switching element QH has a source terminal connected to the first power supply line 2 and a drain terminal connected to the drain terminal of the low-side switching element QL. A source terminal of the low-side switching element QL is connected to the second power supply line 3 . The high-side switching element QH and the low-side switching element QL connected in this manner form an arm portion A, and the inverter 30 has three sets of the arm portions A. As shown in FIG.

Gate terminals of the high-side switching element QH and the low-side switching element QL are connected to the driver 20 to receive the above-described PWM signal with improved drive capability. Also, the drain terminal of the high-side switching element QH of each arm portion A is connected to three terminals (a U-phase terminal, a V-phase terminal, and a W-phase terminal) of the three-phase motor M, respectively.

The zero-cross detection unit 42 detects that the voltage value of the phase voltage of another phase different from the two phases is 3 of the three-phase motor M in a state where the two-phase coil C of the three-phase coils C is energized. The timing when the voltage value of the connection point connected to each of the two terminals via the resistor R1 exceeds the connection point voltage value and the timing when the voltage value of the phase voltage falls below the connection point voltage value are detected as the first zero cross. do.

The state in which the two-phase coil C of the three-phase coils C is energized means that the control unit 10 selects one of the U-phase coil C, the V-phase coil C, and the W-phase coil C as described above. is a state in which the two coils C are energized by PWM control. For this reason, "another phase different from the two phases" means that the control unit 10 selects one of the U-phase coil C, the V-phase coil C, and the W-phase coil C that is not energized by PWM control. This corresponds to the phase having the coil C. Specifically, for example, when a current flows from the U-phase coil C to the V-phase coil C, the W phase corresponds.

The three terminals of the three-phase motor M are a U-phase terminal, a V-phase terminal, and a W-phase terminal. Therefore, one terminal of each of the three resistors R1 is connected to each of the U-phase terminal, the V-phase terminal, and the W-phase terminal, and the other terminals of the three resistors R1 are connected to each other. configure.

One terminal of each of the three resistors R2 is connected to each of the U-phase terminal, the V-phase terminal, and the W-phase terminal, and the other terminal of each of the three resistors R2 constitutes the comparison section 40. It is connected to the non-inverting terminal of each of the three comparators. Furthermore, a connection point is connected to the inverting terminals of the three comparators via a resistor R3. Outputs of the three comparators forming the comparison section 40 are transmitted to the zero-cross detection section 42 . As a result, the zero-cross detection unit 42 detects the timing when the voltage value of the phase voltage (hereinafter referred to as “phase voltage”) of the phase that is not energized exceeds the connection point voltage value, which is the voltage value of the voltage at the connection point, and the phase voltage value. The timing at which the voltage value falls below the connection point voltage value can be identified, and such timing is detected as the first zero crossing.

Here, in FIG. 2 the phase voltages for the phase with coil C that is not energized are shown. In FIG. 2, the state (energization mode) in which the current flows from the W-phase coil C to the U-phase coil C is indicated as "W-phase→U-phase", and in this state, the phase voltage of the V-phase is indicated. Similarly, the state in which the current flows from the W-phase coil C to the V-phase coil C is indicated as "W-phase→V-phase". A state in which a current flows from the U-phase coil C to the V-phase coil C is indicated as "U-phase ⇒ V-phase". In this state, the phase voltage of the V phase is indicated, and the state in which the current flows from the V-phase coil C to the W-phase coil C is indicated as “V phase ⇒ W phase”. In this state, the phase voltage of the U phase is indicated, and the state in which a current flows from the V-phase coil C to the U-phase coil C is indicated as "V phase ⇒ U phase", and this state is indicated. , the phase voltage of the W phase is shown.

As shown in FIG. 2, the zero-cross detection unit 42 detects, for example, when the energization mode is "V phase ⇒ U phase", the voltage value of the phase voltage of the W phase exceeds the connection point voltage value ( time t1) is detected as the first zero cross, and when the energization mode is "W phase ⇒ U phase", the voltage value of the V phase phase voltage falls below the connection point voltage value (time t2) ) is detected as the first zero crossing. The zero-cross detector 42 similarly detects the first zero-cross below. Note that in FIG. 2, the white circle indicates the point in time when the first zero cross is detected.

In addition, when the first zero cross is the timing at which the phase voltage exceeds the connection point voltage value, the zero-cross detection unit 42 detects a phase voltage lower than the connection point voltage value for the first time after the lapse of a predetermined time. "timing" is detected as the second zero cross, and when the first zero cross is the timing when the phase voltage falls below the connection point voltage value, "after a predetermined time has passed, the phase voltage with a voltage value higher than the connection point voltage value is detected for the first time. detected timing” is detected as the second zero crossing.

The case where the first zero cross is the timing at which the phase voltage exceeds the connection point voltage value is time t1 or time t5 in FIG. The predetermined time is the third time counted by the third counting unit 53, details of which will be described later. Therefore, when the first zero cross is the timing at which the phase voltage exceeds the connection point voltage value, the "timing at which the phase voltage having a voltage value lower than the connection point voltage value is detected for the first time after the predetermined time has elapsed" is t2. The point in time and the point in time t9 correspond. Therefore, the zero-cross detection unit 42 detects the time t2 and the time t9 as the second zero-cross.

On the other hand, when the first zero crossing occurs at the timing when the phase voltage falls below the connection point voltage value, it is time t2 or time t9 in FIG. Therefore, when the first zero cross is the timing at which the phase voltage falls below the connection point voltage value, the "timing at which a phase voltage having a voltage value higher than the connection point voltage value is detected for the first time after a predetermined time has elapsed" is t5. The point in time and the point in time t12 correspond. Therefore, the zero-cross detection unit 42 detects the time t5 and the time t12 as the second zero-cross.

The zero-cross detection unit 42 similarly detects the second zero-cross thereafter. The detection result by the zero-cross detection unit 42 is sequentially transmitted to the first counting unit 51, the second counting unit 52, the third counting unit 53, the determining unit 62, and the preliminary counting unit 70, which will be described later. In addition, in FIG. 2, the white circle indicates the point in time when the second zero cross is detected.

Returning to FIG. 1, the first counting unit 51 counts the first time, which is the time from the consecutive first zero crossing to the second zero crossing. The continuous first zero-crossing and second zero-crossing are the first zero-crossing and the second zero-crossing detected along the time series by the zero-crossing detection unit 42 . That is, the first counting unit 51 counts the time from the first zero crossing to the next detected second zero crossing as the first time. Specifically, as shown in FIG. 2, the first counting unit 51 starts counting from time t1 when the first zero cross is detected and counts until time t2 when the second zero cross is detected. The first counting unit 51 resets the counting result when the second zero crossing is detected (time t2). The result of counting by the first counting section 51 at this time corresponds to the first time. Similarly, the first counting unit 51 counts the time from t2 when the first zero cross is detected to t5 when the second zero cross is detected as a first time. The first counting unit 51 similarly counts the first time. The counting result by the first counting section 51 is transmitted to the second counting section 52 and the third counting section 53 to be described later in order each time it is calculated.

Returning to FIG. 1, after the first counting unit 51 counts the first time, the second counting unit 52 sets a second time shorter than the first time based on the first time. count between After counting the first hour by the first counting unit 51 means that the most recent first hour among the first hours counted by the first counting unit 51 is counted at the time when the second counting unit 52 starts counting. It means after being done. Therefore, the end point of the counting of the most recent first time corresponds to the start point of counting by the second counting section 52 .

Setting a time shorter than the first time based on the first time means setting a time shorter than the most recent first time based on the most recent first time. Therefore, the end of counting by the second counting unit 52 corresponds to the point in time when the set second time has elapsed after the end of counting for the most recent first time. Specifically, in calculating the second time set based on the most recent first time, a percentage is set in advance such as 40%, 50%, or 60% of the most recent first time. Good to keep. Also, this ratio can be changed according to the load and rotation speed of the three-phase motor M. Based on this ratio, the second counting section 52 sets the second time.

As shown in FIG. 2, when the most recent first time is the time from t1 to t2, the second counting unit 52 sets the second time based on the first time. , counts from time t2 when counting of the most recent first time ends until the second time elapses. Similarly, when the most recent first time is the time from t2 to t5, the second counting unit 52 sets the second time based on this first time, and Counting is continued until the second time elapses from time t5 when the counting of time ends. The results of counting by the second counting section 52 are sequentially transmitted to the control section 10, the determining section 62 described later, and the preliminary counting section 70 described later.

Returning to FIG. 1, after the first time is counted by the first counting unit 51, the third counting unit 53 sets a third time shorter than the first time based on the first time. count between After counting the first hour by the first counting unit 51 means that the most recent first hour among the first hours counted by the first counting unit 51 is counted at the time when the third counting unit 53 starts counting. It means after being done. Therefore, the end point of the counting of the most recent first time corresponds to the start point of counting by the third counting section 53 . The start of counting by the third counting unit 53 is the same timing as the start of counting by the second counting unit 52 described above.

Setting a time shorter than the first time based on the first time means setting a time shorter than the most recent first time based on the most recent first time. Therefore, the end of the counting by the third counting section 53 is the point in time when the set third time has elapsed after the end of counting for the most recent first time. Specifically, when calculating the third time set based on the most recent first time, a percentage is set in advance such as 60%, 70%, or 80% of the most recent first time. Good to keep. Also, this ratio can be changed according to the load and rotation speed of the three-phase motor M. Based on this ratio, the third counting section 53 sets the third time. Although details will be described later, the second period is used for phase switching by the control unit 10, and the third period is used as a mask period for preventing erroneous detection due to a surge that occurs in response to phase switching. Therefore, it is preferable that the third time is set longer than the second time.

As shown in FIG. 2, the third counting unit 53 sets the third time based on the first time from the time t1 to the time t2. Counting is performed from time t2 when the counting of the first time ends until the third time elapses. Similarly, when the most recent first time is the time from t2 to t5, the third counting unit 53 sets the third time based on the first time, and Counting is continued until the third time elapses from time t5 when the counting of time ends. The counting results of the third counting section 53 are sequentially transmitted to the mask period setting section 60, the determining section 62, and the preliminary counting section 70, which will be described later.

Here, as described above, when the first zero cross is the timing at which the phase voltage exceeds the connection point voltage value, the zero-cross detection unit 42 detects that "a voltage value lower than the connection point voltage value is detected for the first time after a predetermined period of time has elapsed. is detected as the second zero cross, and if the first zero cross is the timing at which the phase voltage drops below the connection point voltage value, "after a predetermined time has elapsed, the phase voltage is higher than the connection point voltage value for the first time. The timing at which the phase voltage of the voltage value is detected is detected as the second zero crossing, but the third time counted by the third counting unit 53 is the predetermined timing when the zero crossing detecting unit 42 described above detects the second zero crossing. used as time.

Returning to FIG. 1, the mask period setting section 60 sets the period during which the third counting section 53 counts the third time period as the mask period. Information indicating the timing at which the third counting section 53 starts counting and the timing at which the counting ends may be transmitted to the mask period setting section 60 . This enables the mask period setting section 60 to specify the period during which the third counting section 53 is counting the third time. The mask period is a period during which detection is avoided in order for the detection unit 61, which will be described later, to detect the position of the rotor with high accuracy. That is, when the energized state of the coil C is switched, a surge (phase switching surge) accompanying this switching is likely to occur. Therefore, it is preferable to set a period during which such a surge is likely to occur as a mask period to avoid detecting the position of the rotor. The end of the most recent first time count corresponds to the beginning of the mask period. It is preferable to set the mask period to coincide with the period counted by the third counting unit 53 . Information indicating the mask period set by the mask period setting unit 60 is sequentially transmitted to the detection unit 61, which will be described later.

Specifically, as shown in FIG. 2, the mask period setting unit 60 sets a period (t4) until the counting result of the third counting unit 53 counted from timing t2 reaches the third time (t4). is set to the mask period.

The detector 61 detects the position of the rotor of the three-phase motor M based on the current flowing through the coil C after the mask period ends and before the next first zero cross is detected. The mask period is a period during which the third counting section 53 counts the third time. Further, when the first counting unit 51 finishes counting the first time, the third counting unit 53 newly starts counting the third time. That is, the mask period setting unit 60 sets the next mask period. Therefore, the detector 61 detects the position of the rotor between the end of the mask period and the start of the next mask period.

Specifically, as shown in FIG. 2, for example, the period from the time (t4) when the counting result of the third counting unit 53 reaches the third time to the time (t5) when the next first zero crossing is detected position detection. By detecting the position of the rotor of the three-phase motor M after the end of the mask period, the detection unit 61 can detect the surge without being affected by the surge.

The detector 61 detects the position of the rotor of the three-phase motor M based on the motor current flowing through the three-phase motor M. As shown in FIG. In this embodiment, the detector 61 detects the motor current (the current flowing through each coil C) and detects (calculates) the position of the rotor. Since this detection is publicly known, the description is omitted. The detector 61 can also be configured to detect the number of rotations of the three-phase motor M based on the position of the rotor. The detection result of the detection unit 61 is transmitted to the control unit 10, and the control unit 10 uses it for PWM control.

The control unit 10 receives the detection result from the detection unit 61 . In addition, the control unit 10 receives the counting result from the second counting unit 52 . As shown in FIG. 2, the control unit 10 performs phase switching when the count result of the second counting unit 52 counted from timing t2 reaches a second time (t3). Specifically, at the timing of t3, the energization mode is switched from “W phase→U phase” to “W phase→V phase”. As a result, the above-described surge occurs for a while after the phase switching.

The determination unit 62 determines whether the second zero crossing detected by the zero crossing detection unit 42 is appropriate based on the first zero crossing newly detected after the second zero crossing was detected. Information indicating the timing at which the zero-cross detection unit 42 detects the second zero-cross is transmitted from the zero-cross detection unit 42 to the determination unit 62 . The first zero cross newly detected after the second zero cross is detected includes the timing at which the second zero cross is detected by the zero cross detector 42, and is newly detected by the zero cross detector 42 after the timing. is the first zero crossing. By configuring the zero-cross detection unit 42 to transmit information indicating the timing at which the first zero-cross is detected by the zero-cross detection unit 42 to the determination unit 62, the determination unit 62 detects the second zero-cross described above. It is possible to identify the newly detected first zero crossing after it was detected.

In the present embodiment, the determination unit 62 determines whether a new first zero crossing is performed before the counting result of the second counting unit 52 becomes equal to the second time or until the counting result of the third counting unit 53 becomes equal to the third time. is detected, it is determined that the immediately preceding second zero crossing is inappropriate. Until the counting result of the second counting section 52 becomes equal to the second time means, for example, from time t2 to time t3 in FIG. Similarly, until the counting result of the third counting section 53 becomes equal to the third time means, for example, from time t2 to time t4 in FIG. In the example of FIG. 2, since the new first zero cross is detected at time t5, the new first zero cross is not detected during counting by the second counting section 52 or during counting by the third counting section 53. do not have. Therefore, the determination unit 62 determines that the immediately preceding second zero cross (the second zero cross detected at time t2) is appropriate.

Similarly, during counting by the second counting unit 52 from time t5 to time t6 or during counting by the third counting unit 53 from time t5 to time t8, the second counting unit 53 from time t9 to time t10 During counting by the counting unit 52, during counting by the third counting unit 53 from time t9 to time t11, during counting by the second counting unit 52 from time t12 to time t13, or from time t12 to time t14 Since no new first zero cross is detected even during counting by the third counting unit 53 up to this point, the determination unit 62 determines that the immediately preceding second zero cross is appropriate.

On the other hand, since a new first zero cross is detected at time t15 during counting by the second counting unit 52 from time t14 or during counting by the third counting unit 53 from time t14, the determination unit 62 determines that the immediately preceding second zero cross at time t14 is not appropriate. The determination result by the determination unit 62 is transmitted to the preliminary counting unit 70, which will be described later.

The determination unit 62 may be configured to determine that the second zero cross is not appropriate when the new first zero cross is not detected at the timing when the second zero cross is detected. A case where a new first zero cross is not detected at the timing when the second zero cross is detected means a case where the second zero cross and the first zero cross are detected at the same timing. Specifically, since the second zero cross and the first zero cross are detected at the same timing at t1, t2, t5, t9, and t12 in FIG. is appropriate. On the other hand, since the first zero cross is not detected at t14, the determination unit 62 determines that the second zero cross at t14 is inappropriate. The determination result of the determination unit 62 is transmitted to the preliminary counting unit 70, which will be described later.

If the determination unit 62 determines that the second zero crossing is not appropriate, the preliminary counting unit 70 determines the time that the second counting unit 52 and the third counting unit 53 use as the first time, and determines that the second zero crossing is not appropriate. The voltage of the second phase voltage after the counting of the third time when the counting is started after the counting of the immediately preceding first time after the first zero crossing, which is the basis of the first time until the determined second zero crossing, is detected. The time until the magnitude relationship between the value and the connection point voltage value is switched is counted as the preliminary first time. The fact that the determination unit 62 has determined that the second zero cross is not appropriate can be identified by the determination result transmitted from the determination unit 62 . Further, when the determination unit 62 determines that the second zero crossing is not appropriate, the first time that ends counting at the second zero crossing is not appropriate. On the other hand, as described above, the second counting section 52 sets the second time based on the previous first time, and the third counting section 53 sets the third time based on the previous first time. Therefore, if the second counting unit 52 and the third counting unit 53 count the second time and the third time using the inappropriate first time, the phase switching performed based on the second time and the third time The mask period that is set based on this is no longer appropriate, and the control unit 10 cannot appropriately switch the energization state of the coil C, and the three-phase motor M cannot be driven stably.

Therefore, when the determination unit 62 determines that the second zero crossing is not appropriate, the second counting unit 52 and the third counting unit 53 perform preliminary counting instead of the first time counted by the first counting unit 51. The preliminary first time counted by unit 70 is used to set the second and third times.

Preliminary counting section 70 starts counting when the first zero crossing is detected by zero crossing detection section 42 as the start time of the preliminary first time. Therefore, the starting time of the preliminary first time coincides with the starting time of the coefficient of the first counting section 51 . The preliminary counting unit 70 starts counting at the same timing as the counting of the preliminary first time, and after the completion of the counting of the third time, the voltage value of the first phase voltage and the connection point voltage value The change of the relationship is ignored, and when the next change of the size relationship after the ignored change of the size relationship is detected, the counting is finished and the counting result is reset. Therefore, the preliminary counting section 70 continues counting even after the first counting section 51, which started counting at the same timing, resets the counting result. The preliminary counting unit 70 resets the counting result with the point of time when the switching of the magnitude relationship next to the switching of the neglected magnitude relationship is detected as the end time.

Here, as shown in FIG. 2, the time for which the preliminary counting section 70 counts is longer than the time for which the first counting section 51 starts counting at the same timing. Therefore, in the first preliminary time, when counting is started only from the timing when the phase voltage of the phase having the non-energized coil C exceeds the connection point voltage value, the phase voltage of the phase having the non-energized coil C is connected. If the phase voltage of the phase having the non-energized coil C cannot start counting from the timing when it falls below the point voltage value and starts counting only from the timing when the phase voltage falls below the connection point voltage value, the non-energized coil C can not start counting from the timing when the phase voltage of the phase with is above the node voltage value.

Therefore, the preliminary counting section 70 preferably has a first preliminary counting section 71 and a second preliminary counting section 72 . The first preliminary counting unit 71 starts counting when the phase voltage with a voltage value lower than the connection point voltage value exceeds the connection point voltage value, and the second preliminary counting unit 72 starts counting the voltage higher than the connection point voltage value. The counting should start when the phase voltage of the value is below the node voltage value.

That is, as shown in FIG. 2, the first preliminary counting unit 71 calculates the phase voltages at times t1, t5, and t5 when the phase voltage having a voltage value lower than the connection point voltage value exceeds the connection point voltage value. Counting is started at time t12, and the second pre-counter 72 counts when the phase voltage having a voltage value higher than the connection point voltage value falls below the connection point voltage value at time t2, time t9, and time t15. Start counting at the time of .

Thereby, even if one of the first preliminary counting section 71 and the second preliminary counting section 72 is counting, the other can start counting. Therefore, the preliminary first time can always be prepared as a backup for the first time by the first counting unit 51, and the determination unit 62 determines that the second zero crossing is not appropriate, that is, if the first time is not appropriate, that Since the second time and the third time can be set using the first preliminary time at the point in time, the detection unit 61 can appropriately detect the position of the rotor, and the control unit 10 can appropriately detect the position of the coil C. It becomes possible to switch the energized state.

Specifically, at time t15 in FIG. 2, if it is determined that the immediately preceding second zero crossing (at time t14) is not appropriate, the second time and the third time that start counting from time t15 are For setting, a preliminary first time from time t12 to time t15 is used. This makes it possible to appropriately count the second time from t15 to t16 and the third time from t15 to t17.

The configuration of the first preliminary counting section 71 and the second preliminary counting section 72 can be said as follows. The first preliminary counting unit 71 and the second preliminary counting unit 72 start counting at the same timing, and after the lapse of the third time, the voltage value of the phase voltage and the connection point voltage value change for the first time. Counting is continued even if there is, and the counting result is reset when the phase is switched after the first zero crossing is detected.

That is, in FIG. 2, the first preliminary counting unit 71 starts counting at the same timing t5, and after the lapse of the third time (after t8), the voltage value of the phase voltage and the connection point voltage Even if there is a first change in magnitude (switching at time t9) from the value, counting is continued, and after the first zero crossing is detected (time t9), the phase is switched (at time t10). time) to reset the counting result.

Similarly, after the third time (after t11) when the second preliminary counting unit 72 started counting at the same timing t9, the voltage value of the phase voltage and the connection point voltage value Even if there is a first change in magnitude (switching at time t12), counting is continued, and after the first zero cross is detected (time t12), at the time when the phase is switched (time t13) Reset the counting result.

As a result, the counting results of the first preliminary counting section 71 and the second preliminary counting section 72 can be reset while the rotor is properly rotating, and it is possible to prepare for the case where it is determined that the second zero crossing is not proper. .

The configuration of the first preliminary counting section 71 and the second preliminary counting section 72 can also be said as follows. The first preliminary counting unit 71 and the second preliminary counting unit 72 start counting at the same timing, and after the third time has passed, the voltage value of the phase voltage and the If there is a change in magnitude with the connection point voltage value, the counting result is reset when the next first zero cross is detected.

That is, in FIG. 2, the first preliminary counting unit 71 starts counting at the same timing t12, and after the third time has elapsed (after t14), the second zero crossing at time t14 Until the switching is performed (up to time t16), the voltage value of the phase voltage and the connection point voltage value are switched in magnitude (switching in magnitude between time t14 and time t15). If there is, the count result is reset at the time when the next first zero cross is detected (at time t15).

As a result, when it is determined that the second zero crossing is not appropriate, the counting results of the first preliminary counting section 71 and the second preliminary counting section 72 can be used to set the second time and the third time. Become.

[Other embodiments]
In the above embodiment, the third time is set to be longer than the second time, but the third time may be set to be the same as the second time.

In the above embodiment, the determination unit 62 waits until the counting result of the second counting unit 52 becomes equal to the second time or until the counting result of the third counting unit 53 becomes equal to the third time. It has been described that when one zero cross is detected, it is determined that the immediately preceding second zero cross is inappropriate. Further, it has been described that the determination unit 62 determines that the second zero cross is not appropriate when the first zero cross is not detected at the timing when the second zero cross is detected. The determination unit 62 can also be configured to determine whether or not the second zero crossing is inappropriate using any one of the determination processes described above. Furthermore, the determination unit 62 can be configured to determine whether or not the second zero crossing is appropriate using determination processing different from the determination processing described above.

In the above embodiment, the preliminary counting section 70 has been described as having the first preliminary counting section 71 and the second preliminary counting section 72, but the preliminary counting section 70 includes the first preliminary counting section 71 and the second preliminary counting section. 72 , or may be configured to include a preliminary counting section in addition to the first preliminary counting section 71 and the second preliminary counting section 72 . Furthermore, the preliminary counting unit 70 starts counting when the phase voltage with a voltage value lower than the connection point voltage value exceeds the connection point voltage value, and after the counting ends, the voltage higher than the connection point voltage value Start counting when the phase voltage of the value falls below the connection point voltage value, and after the end of the counting, start counting when the phase voltage with a voltage value lower than the connection point voltage value exceeds the connection point voltage value. It may be configured as follows.

Although the motor control device 1 has been described in the above embodiment, it is also possible to configure the electric pump to be driven by the three-phase motor M driven and controlled by the motor control device 1 . In such a configuration, when the electric pump is a water pump, the motor control device 1 can appropriately operate the three-phase motor even when the load suddenly increases, such as when the amount of gas present in the fluid suddenly decreases. It is possible to drive and control M. Further, when the electric pump is an oil pump, the motor control device 1 can appropriately drive and control the three-phase motor M even when the load suddenly increases, such as when the viscosity of the fluid suddenly decreases. is.

In the above embodiment, the high-side switching element QH uses a P-MOSFET, and the low-side switching element QL uses an N-MOSFET. However, the configuration is not particularly limited. , for example, both the high-side switching element QH and the low-side switching element QL may be configured using N-MOSFETs. In this case, it is preferable to provide a booster circuit such as a charge pump.

The present invention relates to a motor control device for controlling the drive of a three-phase motor by switching energization states of coils of the three-phase motor, and an electric pump controlled by the three-phase motor driven and controlled by such a motor control device. It is possible to use

1: Motor control device 10: Control unit 42: Zero cross detection unit 51: First counting unit 52: Second counting unit 53: Third counting unit 60: Mask period setting unit 61: Detecting unit 62: Judging unit 70: Preliminary counting Part 71: First preliminary counting part 72: Second preliminary counting part C: Coil M: Three-phase motor R1: Resistor

Claims (5)

A motor control device for controlling the drive of the three-phase motor by switching the energized state of the coils of the three-phase motor,
In a state in which the two-phase coils of the three-phase coils are energized, the voltage value of the other one-phase voltage different from the two-phase coils is applied to each of the three terminals and the resistance of the three-phase motor. The timing at which the voltage value of the voltage at the connection point connected via the device exceeds the connection point voltage value and the timing at which the voltage value of the phase voltage falls below the connection point voltage value are detected as first zero crosses, and the first zero crossing is detected. When the first zero cross is the timing at which the phase voltage exceeds the connection point voltage value, the timing at which the phase voltage having a voltage value lower than the connection point voltage value is detected for the first time after the elapse of a predetermined time is defined as the second zero cross. When the first zero crossing is the timing at which the phase voltage falls below the connection point voltage value, the phase voltage having a voltage value higher than the connection point voltage value is detected for the first time after the predetermined time has elapsed. a zero-cross detection unit that detects the timing as a second zero-cross;
a first counting unit that counts a first time that is the time from the first zero crossing to the second zero crossing;
a second counting unit that counts a period of time after counting the first time by the first counting unit until a second time set as a time shorter than the first time elapses based on the first time; ,
After the first time is counted by the first counting unit, counting is performed until a third time, which is set as a time shorter than the first time based on the first time and is used as the predetermined time, elapses. a third counting unit that
During the period in which the third counting unit counts the third time, the first zero cross and the second zero cross can be detected, and the position of the rotor of the three-phase motor can be detected. a mask period setting unit for setting as a mask period without
a detection unit that detects the position of the rotor based on the current flowing through the coil after the mask period ends and until the next first zero cross is detected;
a control unit that switches the energization state of the coil based on the detected position of the rotor and the counting result of the second counting unit;
a determination unit that determines whether the second zero cross detected by the zero cross detection unit is appropriate based on the first zero cross newly detected after the second zero cross is detected;
When the determination unit determines that the second zero crossing is not appropriate, the time that the second counting unit and the third counting unit use as the first time, and the time that is determined to be inappropriate The second phase voltage after counting of the third time, which starts counting after counting of the first time immediately before the detection of the first zero cross, which is the basis of the first time until the second zero cross. a preliminary counting unit that counts the time until the magnitude relationship between the voltage value of and the connection point voltage value is switched as a preliminary first time;
A motor controller comprising: The determination unit determines whether the new first zero crossing is reached before the counting result of the second counting unit becomes equal to the second time or by the time the counting result of the third counting unit becomes equal to the third time. 2. The motor control device according to claim 1, wherein if detected, the immediately preceding second zero cross is determined to be inappropriate. 3. The motor control device according to claim 1, wherein the determination unit determines that the second zero cross is not appropriate when the first zero cross is not detected at the timing when the second zero cross is detected. The preliminary counting unit includes a first preliminary counting unit that starts counting when the phase voltage having a voltage value lower than the connection point voltage value exceeds the connection point voltage value, and a voltage higher than the connection point voltage value. 4. A motor controller according to any one of claims 1 to 3, comprising a second pre-counter for starting counting when said phase voltage of value falls below said node voltage value. An electric pump driven by the three-phase motor driven and controlled by the motor control device according to any one of claims 1 to 4.

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