WO2023276320A1

WO2023276320A1 - Motor control device and electric pump device

Info

Publication number: WO2023276320A1
Application number: PCT/JP2022/012010
Authority: WO
Inventors: 英生岸田
Original assignee: 日本電産株式会社
Priority date: 2021-06-29
Filing date: 2022-03-16
Publication date: 2023-01-05

Abstract

One embodiment of a motor control device according to the present invention controls a three-phase motor having saliency through a sensorless 120-degree energization method, and is provided with: a drive circuit for converting a direct-current power supply voltage to three-phase alternating-current voltage and supplying the alternating current voltage to a three-phase motor; a current detection unit for detecting the current flowing through the three-phase motor; and a control unit for outputting to the drive circuit a switching control signal with which the energization pattern of the three-phase motor is switched at 60-degree intervals, and a three-phase alternating-current voltage in which a high-frequency voltage having a higher frequency than the frequency of the three-phase alternating-current voltage has been superposed is supplied to the three-phase motor. The control unit generates an inductance change signal correlated with an inductance change, on the basis of a detected current obtained from the current detection unit, and controls the timing for switching of the energization pattern on the basis of the inductance change signal.

Description

Motor control device and electric pump device

The present invention relates to a motor control device and an electric pump device.

Conventionally, the high-frequency voltage application method (HFI) has been known as one of the sensorless vector control technologies for motors. The HFI technique is a technique for estimating the rotational position of a motor based on a response current obtained by applying a high-frequency voltage having a frequency higher than that of the driving voltage of the motor to the motor.

Patent Document 1 discloses a method of estimating the rotational position of a motor using HFI technology. The method of Patent Document 1 includes steps of supplying a driving voltage superimposed with a high-frequency voltage to a stationary portion of a motor, extracting a predetermined frequency component from the current flowing in the stationary portion as an extracted current, extracting current and extracting current. obtaining a composite signal relating to the amplitude of the extracted current by calculating the sum of squares of the phase-shifted current and the phase-shifted current obtained by shifting the phase of π/2, and obtaining the rotational position of the rotating part based on the composite signal and have

JP 2016-201923 A

HFI technology is a technology developed on the premise of performing sensorless vector control. On the other hand, there are cases where a sensorless 120-degree energization method is used as a control method for motors for in-vehicle use, home appliance use, or industrial use. In the sensorless 120-degree energization method, there is no need to perform coordinate conversion calculations required for sensorless vector control, so an inexpensive control circuit with low calculation capability can be used. Therefore, there is a demand for the development of a motor control technology that applies the HFI technology to the sensorless 120-degree energization method and allows the use of a less expensive control circuit.

One aspect of the motor control device of the present invention is a motor control device that controls a three-phase motor having saliency by a sensorless 120-degree energization method, wherein the DC power supply voltage is converted into a three-phase AC voltage to convert the three-phase A drive circuit for supplying power to the motor, a current detection unit for detecting the current flowing through the three-phase motor, and an energization pattern of the three-phase motor that is switched at intervals of 60 degrees and has a frequency higher than the frequency of the three-phase AC voltage. a control unit that outputs to the drive circuit a switching control signal for supplying the three-phase AC voltage superimposed with a high-frequency voltage having a three-phase AC voltage to the three-phase motor; An inductance change signal correlated with a change in inductance is generated based on the detected current, and the switching timing of the energization pattern is controlled based on the inductance change signal.

One aspect of the electric pump device of the present invention is a three-phase motor having saliency, and a pump positioned on one side in the axial direction of the rotation shaft of the three-phase motor and driven by the three-phase motor via the rotation shaft. and the motor control device of the above aspect for controlling the three-phase motor by a sensorless 120-degree energization method.

According to the above aspect of the present invention, there are provided a motor control device and an electric pump device that can control a motor by a sensorless 120-degree energization method that applies HFI technology and that can use a less expensive control circuit.

FIG. 1 is a block diagram schematically showing an electric pump device 1 including a motor control device 10 according to the first embodiment of the invention. FIG. 2 is a diagram showing an example of six energization patterns used in the sensorless 120-degree energization method. FIG. 3 is a functional block diagram showing each function of the control unit 13 of the first embodiment by blocks. FIG. 4 is a timing chart showing temporal correspondences between the U-phase inductance change signal Zu, the V-phase inductance change signal Zv, the W-phase inductance change signal Zw, and the energization pattern. FIG. 5 is a block diagram schematically showing an electric pump device 2 having a motor control device 10A according to a second embodiment of the invention. FIG. 6 is a functional block diagram showing each function of the control unit 13A according to the second embodiment. FIG. 7 is a timing chart showing temporal correspondences between the U-phase inductance change signal Zu, the V-phase inductance change signal Zv, the W-phase inductance change signal Zw, the bus line inductance change signal Zb, and the energization pattern.

An embodiment of the present invention will be described in detail below with reference to the drawings.
[First Embodiment]
First, a first embodiment of the present invention will be described. FIG. 1 is a block diagram schematically showing an electric pump device 1 including a motor control device 10 according to the first embodiment of the invention. As shown in FIG. 1 , the electric pump device 1 includes a motor control device 10 and an electric pump 40 . Electric pump 40 includes three-phase motor 20 and pump 30 . As an example, the electric pump device 1 is a device that supplies cooling oil F to a drive motor mounted on a hybrid vehicle.

The three-phase motor 20 has saliency. The three-phase motor 20 is a sensorless motor that does not have a position sensor such as a hall sensor. As an example, the three-phase motor 20 is an inner rotor type three-phase brushless DC motor. The three-phase motor 20 has a shaft 21 that is a rotating shaft, a U-phase terminal 22u, a V-phase terminal 22v, and a W-phase terminal 22w.

Although not shown in FIG. 1, the three-phase motor 20 has a motor housing, and a rotor and a stator housed in the motor housing. The rotor is a rotating body that is rotatably supported by bearing components inside the motor housing. The stator is fixed inside the motor housing so as to surround the outer peripheral surface of the rotor, and generates an electromagnetic force necessary to rotate the rotor.

The shaft 21 is a shaft-shaped body coaxially joined to the rotor while axially penetrating the radially inner side of the rotor. The U-phase terminal 22u, the V-phase terminal 22v, and the W-phase terminal 22w are metal terminals exposed from the surface of the motor housing. Although details will be described later, the U-phase terminal 22u, the V-phase terminal 22v, and the W-phase terminal 22w are electrically connected to the drive circuit 11 of the motor control device 10, respectively.

The three-phase motor 20 has three-phase coils (not shown). A three-phase coil includes a U-phase coil, a V-phase coil, and a W-phase coil. A U-phase coil, a V-phase coil, and a W-phase coil are exciting coils provided in the stator, respectively. The U-phase coil, the V-phase coil, and the W-phase coil are delta-connected or star-connected inside the three-phase motor 20 . By controlling the energization states of the U-phase coil, the V-phase coil, and the W-phase coil by the motor control device 10, an electromagnetic force necessary to rotate the rotor is generated. As the rotor rotates, the shaft 21 also rotates in synchronization with the rotor.

The pump 30 is located on one axial side of the shaft 21 of the three-phase motor 20 and is driven by the three-phase motor 20 via the shaft 21 . As the pump 30 is driven by the three-phase motor 20, the pump 30 discharges the cooling oil F as a fluid. The pump 30 has an oil inlet 31 and an oil outlet 32 . The cooling oil F is sucked into the pump 30 through the oil inlet 31 and then discharged out of the pump 30 through the oil outlet 32 . In this manner, the electric pump 40 is configured by connecting the pump 30 and the three-phase motor 20 side by side in the axial direction of the shaft 21 .

The motor control device 10 is a device that controls a three-phase motor 20 having saliency using a sensorless 120-degree energization method. The motor control device 10 controls the rotation speed of the three-phase motor 20 based on a command signal VC output from a host control device (not shown). As an example, the host controller is an in-vehicle ECU (Electronic Control Unit) mounted on a hybrid vehicle. The command signal VC may be a rotation speed command signal that instructs the rotation speed of the three-phase motor 20 or a voltage command signal that instructs the voltage of the three-phase motor 20 .
The motor control device 10 includes a drive circuit 11, a U-phase current sensor 12u, a V-phase current sensor 12v, a W-phase current sensor 12w, a control section 13, and a storage section .

The drive circuit 11 is a circuit that converts the DC power supply voltage _VM into a three-phase AC voltage and supplies it to the three-phase motor 20 . The drive circuit 11 converts the DC power supply voltage _VM supplied from the DC power supply 200 into a three-phase AC voltage and outputs the three-phase AC voltage to the three-phase motor 20 . As an example, the DC power supply 200 is one of a plurality of batteries mounted on a hybrid vehicle, and supplies a _12V DC power supply voltage VM to a 12V vehicle-mounted system, for example.

The drive circuit 11 includes a U-phase upper arm switch _{QUH, a V-phase upper arm switch QVH} _, a W-phase upper arm switch _QWH , a U-phase lower arm switch _QUL , and a V-phase lower arm switch _QVL . and a W-phase lower arm switch _QWL . Each arm switch in this embodiment is, for example, an N-channel MOS-FET.

The drain terminal of U-phase upper arm switch _{QUH, the drain terminal of V-phase upper arm switch QVH} _, and the drain terminal of W-phase upper arm switch _QWH are electrically connected to the positive terminal of DC power supply 200, respectively. The source terminal of the U-phase lower arm switch _QUL , the source terminal of the V-phase lower arm switch _QVL , and the source terminal of the W-phase lower arm switch _QWL are electrically connected to the negative terminal of the DC power supply 200, respectively. be done. A negative terminal of the DC power supply 200 is electrically connected to the in-vehicle ground.

The source terminal of the U-phase upper arm switch _QUH is electrically connected to the U-phase terminal 22u of the three-phase motor 20 and the drain terminal of the U-phase lower arm switch _QUL . The source terminal of the V-phase upper arm switch _QVH is electrically connected to the V-phase terminal 22v of the three-phase motor 20 and the drain terminal of the V-phase lower arm switch _QVL . The source terminal of the W-phase upper arm switch QWH is electrically connected to the W-phase terminal _22w of the three-phase motor 20 and the drain terminal of the W-phase lower arm switch _QWL .

A gate terminal of the U-phase upper arm switch _{QUH, a gate terminal of the V-phase upper arm switch QVH} _, and a gate terminal of the W-phase upper arm switch _QWH are electrically connected to the control unit 13, respectively. The gate terminal of the U-phase lower arm switch _QUL , the gate terminal of the V-phase lower arm switch _QVL , and the gate terminal of the W-phase lower arm switch _QWL are also electrically connected to the control unit 13. be.

As described above, the drive circuit 11 is configured by a three-phase full bridge circuit having three upper arm switches and three lower arm switches. The drive circuit 11 configured as described above converts the DC power supply voltage _VM supplied from the DC power supply 200 into a three-phase AC voltage by controlling the switching of each arm switch by the control unit 13 to drive the three-phase motor. 20.

In this embodiment, a sensorless 120-degree energization method is used as the energization method for the three-phase motor 20 . As an example, when the sensorless 120-degree energization method is used, switching of each arm switch is controlled based on the energization pattern shown in FIG. As shown in FIG. 2, the energization pattern of the sensorless 120-degree energization method includes six energization patterns PA1, PA2, PA3, PA4, PA5 and PA6. In FIG. 2, among "ON" and "OFF" arranged in a row from "Q _UH " to "Q _WL ", "ON" means that the corresponding arm switch is controlled to be ON, and "OFF". means that the corresponding arm switch is controlled to be off.

In the energization pattern PA1, the U-phase upper arm switch QUH and the _{W-phase lower arm switch QWL} _are controlled to be ON, and the remaining arm switches are controlled to be OFF. As an example, in the energization pattern PA1, only the U-phase upper arm switch _QUH is switching-controlled at a predetermined switching duty ratio.

In the energization pattern PA2, the V-phase upper arm switch _QVH and the W-phase lower arm switch _QWL are controlled to be ON, and the remaining arm switches are controlled to be OFF. As an example, in the energization pattern PA2, only the V-phase upper arm switch _QVH is switching-controlled at a predetermined switching duty ratio.

In the energization pattern PA3, the V-phase upper arm switch _QVH and the U-phase lower arm switch _QUL are controlled to be ON, and the remaining arm switches are controlled to be OFF. As an example, even in the energization pattern PA3, only the V-phase upper arm switch _QVH is switching-controlled at a predetermined switching duty ratio.

In the energization pattern PA4, the W-phase upper arm switch _{QWH and the U-phase lower arm switch QUL} _are controlled to be ON, and the remaining arm switches are controlled to be OFF. As an example, in the energization pattern PA4, only the W-phase upper arm switch _QWH is switching-controlled at a predetermined switching duty ratio.

In the energization pattern PA5, the W-phase upper arm switch _{QWH and the V-phase lower arm switch QVL} _are controlled to be ON, and the remaining arm switches are controlled to be OFF. As an example, even in the energization pattern PA5, only the W-phase upper arm switch _QWH is switching-controlled at a predetermined switching duty ratio.

In the energization pattern PA6, the U-phase upper arm switch _{QUH and the V-phase lower arm switch QVL} _are controlled to be ON, and the remaining arm switches are controlled to be OFF. As an example, in the energization pattern PA6, only the U-phase upper arm switch _QUH is switching-controlled at a predetermined switching duty ratio.

A rotating magnetic field that rotates the shaft 21 of the three-phase motor 20 by 360 degrees in a fixed direction is generated by sequentially switching the six energization patterns as described above at intervals of 60 degrees in electrical angle. In other words, the shaft 21 of the three-phase motor 20 rotates in a certain direction by an electrical angle of 60 degrees during the period in which the switching control of each arm switch is performed in one energization pattern. The speed at which the energization pattern is switched is called the commutation frequency Fs. The unit of the commutation frequency Fs is "Hz". The commutation frequency Fs is represented by "Fs=1/P", where P (seconds) is the period during which switching control is performed in one energization pattern.

In the conventional general sensorless 120-degree energization method, the point where the induced voltage exposed to each of the U-phase terminal 22u, the V-phase terminal 22v, and the W-phase terminal 22w intersects the neutral point potential (=V _M /2) is By detecting the zero-cross points and controlling the switching timing of the energization patterns based on the detection result of the zero-cross points, the six energization patterns are sequentially switched at intervals of 60 degrees. In contrast, in the present embodiment, the current flowing through the three-phase motor 20 is detected while supplying the three-phase AC voltage superimposed with the high-frequency voltage to the three-phase motor 20 . The detected current includes a high-frequency current having the same frequency as the high-frequency voltage superimposed on the three-phase AC voltage. In this embodiment, an inductance change signal correlated with a change in inductance is generated based on the detected current including the high-frequency current as described above, and the switching timing of the energization pattern is controlled based on the generated inductance change signal.

The U-phase current sensor 12u, the V-phase current sensor 12v, and the W-phase current sensor 12w are current detection units that detect the current flowing through the three-phase motor 20. In the following description, the U-phase current sensor 12u, the V-phase current sensor 12v, and the W-phase current sensor 12w may be collectively referred to as "current detector 12". The current detector 12 detects currents flowing through the three phases of the three-phase motor 20 . The U-phase current sensor 12u detects a U-phase line current and outputs the detection result to the control unit 13 as a U-phase detection current Iu. The V-phase current sensor 12v detects a V-phase line current and outputs the detection result to the control unit 13 as a V-phase detection current Iv. The W-phase current sensor 12w detects a W-phase line current and outputs the detection result to the control unit 13 as a W-phase detection current Iw. As an example, the U-phase current sensor 12u, the V-phase current sensor 12v, and the W-phase current sensor 12w are CT-type current sensors.

The control unit 13 is, for example, a microprocessor such as an MCU (Microcontroller Unit). A command signal VC output from a host controller (not shown) is input to the control unit 13 . Further, the controller 13 includes a U-phase detection current Iu output from the U-phase current sensor 12u, a V-phase detection current Iv output from the V-phase current sensor 12v, and a W-phase detection current output from the W-phase current sensor 12w. A phase detection current Iw is input. The control unit 13 is communicably connected to the storage unit 14 via a communication bus (not shown).

The control unit 13 supplies the three-phase motor 20 with a three-phase AC voltage in which the energization pattern of the three-phase motor 20 is switched at intervals of 60 degrees and a high-frequency voltage having a higher frequency than the frequency of the three-phase AC voltage is superimposed. The switching control signal obtained is output to the drive circuit 11 . As an example, the switching control signal is a PWM (Pulse Width Modulation) signal supplied to the gate terminal of each arm switch provided in the drive circuit 11 .

The control unit 13 generates an inductance change signal that correlates with the change in inductance based on the detected current obtained from the current detection unit 12, and controls the switching timing of the energization pattern based on the inductance change signal. Based on the three-phase detection currents (the U-phase detection current Iu, the V-phase detection current Iv, and the W-phase detection current Iw) obtained from the current detection unit 12, the control unit 13 detects three-phase currents correlated with changes in the three-phase inductances. , and controls the switching timing of the energization pattern based on the three-phase inductance change signals.

As described above, the detected currents Iu, Iv, and Iw detected by the current detector 12 include high-frequency currents having the same frequency as the high-frequency voltage superimposed on the three-phase AC voltage. The control unit 13 extracts, as extracted currents, frequency components having the same frequency as the high-frequency voltage superimposed on the three-phase AC voltage from the detected currents Iu, Iv, and Iw obtained from the current detection unit 12, and extracts extracted currents and , and a phase-shifted current obtained by shifting the phase of the extracted current by π/2 to generate an inductance change signal. The control unit 13 acquires the phase-shifted current by performing a Hilbert transform on the extracted current. In this embodiment, the Hilbert transform is performed by an FIR filter.

The storage unit 14 is used as a non-volatile memory for storing programs and various setting data necessary for the control unit 13 to execute various processes, and as a temporary storage destination for data when the control unit 13 executes various processes. and volatile memory. The nonvolatile memory is, for example, EEPROM (Electrically Erasable Programmable Read-Only Memory) or flash memory. Volatile memory is, for example, RAM (Random Access Memory). The storage unit 14 stores various data necessary to control the three-phase motor 20 by the sensorless 120-degree energization method. For example, the storage unit 14 pre-stores the energization pattern shown in FIG. As shown in FIG. 1 , the storage unit 14 may be provided outside the control unit 13 or may be built in the control unit 13 .

FIG. 3 is a functional block diagram showing each function of the control unit 13 in blocks. As shown in FIG. 3 , the control section 13 has an inductance change signal generation section 50 , an energization pattern setting section 60 , a high frequency voltage application section 70 , an addition section 80 and a PWM conversion section 90 . Some or all of the inductance change signal generation unit 50, the energization pattern setting unit 60, the high frequency voltage application unit 70, the addition unit 80, and the PWM conversion unit 90 are implemented by software that operates on the processor core incorporated in the control unit 13. Alternatively, it may be implemented in hardware including analog and digital circuitry.

The inductance change signal generation unit 50 correlates the three-phase inductance changes based on the three-phase detection currents (the U-phase detection current Iu, the V-phase detection current Iv, and the W-phase detection current Iw) obtained from the current detection unit 12. A three-phase inductance change signal is generated. The inductance change signal generation unit 50 includes a first BPF (Band Path Filter) 51, a second BPF 52, a third BPF 53, a first Hilbert transform unit 54, a second Hilbert transform unit 55, It has a third Hilbert transform unit 56 , a first root-sum-of-squares operation unit 57 , a second root-sum-square operation unit 58 , and a third root-sum-square operation unit 59 .

The first BPF 51 extracts, as a U-phase extraction current Iuh, a frequency component having the same frequency as the high-frequency voltage superimposed on the three-phase AC voltage from the U-phase detection current Iu obtained from the U-phase current sensor 12u. The U-phase extracted current Iuh is output to the first Hilbert transform section 54 .
The second BPF 52 extracts, as a V-phase extraction current Ivh, a frequency component having the same frequency as the high-frequency voltage superimposed on the three-phase AC voltage from the V-phase detection current Iv obtained from the V-phase current sensor 12v. The V-phase extracted current Ivh is output to the second Hilbert transform section 55 .
The third BPF 53 extracts, as a W-phase extraction current Iwh, a frequency component having the same frequency as the high-frequency voltage superimposed on the three-phase AC voltage from the W-phase detection current Iw obtained from the W-phase current sensor 12w. The W-phase extracted current Iwh is output to the third Hilbert transform section 56 .

The first Hilbert transform unit 54 transforms the U-phase extracted current Iuh into a complex analytic signal having a real part Xu and an imaginary part Yu. The real part Xu is the same as the U-phase extraction current Iuh. The imaginary part Yu is obtained by the Hilbert transform performed by the FIR filter. The imaginary part Yu is a phase-shifted current obtained by shifting the phase of the U-phase extracted current Iuh by π/2. The first Hilbert transform unit 54 outputs the real part Xu and the imaginary part Yu to the first root-sum-of-squares operation unit 57 .

The second Hilbert transform unit 55 transforms the V-phase extracted current Ivh into a complex analytic signal having a real part Xv and an imaginary part Yv. The real part Xv is the same as the V-phase extraction current Ivh. The imaginary part Yv is obtained by the Hilbert transform performed by the FIR filter. The imaginary part Yv is a phase-shifted current obtained by shifting the phase of the V-phase extracted current Ivh by π/2. The second Hilbert transform unit 55 outputs the real part Xv and the imaginary part Yv to the second root-sum-of-squares operation unit 58 .

The third Hilbert transform unit 56 transforms the W-phase extracted current Iwh into a complex analytic signal having a real part Xw and an imaginary part Yw. The real part Xw is the same as the W-phase extraction current Iwh. The imaginary part Yw is obtained by the Hilbert transform performed by the FIR filter. The imaginary part Yw is a phase-shifted current obtained by shifting the phase of the W-phase extracted current Iwh by π/2. The third Hilbert transform unit 56 outputs the real part Xw and the imaginary part Yw to the third root-sum-of-squares operation unit 59 .

The first root-sum-of-squares calculator 57 calculates the root-of-square sum of the real part Xw and the imaginary part Yw obtained from the first Hilbert transform part 54, thereby obtaining A change signal Zu is calculated. In other words, the first square-sum-square calculator 57 calculates the square-root sum of the squares of the U-phase extracted current Iuh and the phase-shifted current obtained by shifting the phase of the U-phase extracted current Iuh by π/2. A U-phase inductance change signal Zu is calculated. The first sum-of-squares-square-root calculator 57 outputs the U-phase inductance change signal Zu to the energization pattern setting unit 60 .

A second root-sum-of-squares calculator 58 calculates the root-sum-square of the real part Xv and the imaginary part Yv obtained from the second Hilbert transform part 55, thereby obtaining A change signal Zv is calculated. In other words, the second root-sum-of-squares calculator 58 calculates the square root of the sum of squares of the V-phase extracted current Ivh and the phase-shifted current obtained by shifting the phase of the V-phase extracted current Ivh by π/2. A V-phase inductance change signal Zv is calculated. Second sum-of-squares square root calculator 58 outputs V-phase inductance change signal Zv to energization pattern setting unit 60 .

A third root-sum-square calculator 59 calculates the root-sum-square of the real part Xw and the imaginary part Yw obtained from the third Hilbert transform part 56, thereby obtaining a W-phase inductance correlated with a change in the W-phase inductance. A change signal Zw is calculated. In other words, the third root-sum-square calculator 59 calculates the root-sum-square of the W-phase extracted current Iwh and the phase-shifted current obtained by shifting the phase of the W-phase extracted current Iwh by π/2. A W-phase inductance change signal Zw is calculated. The third root-sum-of-squares calculator 59 outputs the W-phase inductance change signal Zw to the energization pattern setting unit 60 .

In addition, for details of the calculation method for converting the extracted current into a complex analytic signal having a real part and an imaginary part and the calculation method of the square root of the sum of the squares of the real part and the imaginary part, see Japanese Patent Application Laid-Open No. 2016-201923. Please refer to

The energization pattern setting unit 60 switches the energization pattern based on the U-phase inductance change signal Zu, the V-phase inductance change signal Zv, and the W-phase inductance change signal Zw. FIG. 4 is a timing chart showing temporal correspondences between the U-phase inductance change signal Zu, the V-phase inductance change signal Zv, the W-phase inductance change signal Zw, and the energization pattern.

As shown in FIG. 4, the energization pattern setting unit 60 compares the U-phase inductance change signal Zu with a predetermined first threshold value Zuth, and sets the energization pattern at the timing when the U-phase inductance change signal Zu becomes equal to or greater than the first threshold value Zuth. switch. In the example shown in FIG. 4, the energization pattern setting unit 60 switches the energization pattern at times t1, t4, t7, t10, and t13. Hereinafter, times t1, t4, t7, t10, and t13 are referred to as first energization pattern switching timings. It should be noted that the first threshold value Zuth, which is the value of the U-phase inductance change signal Zu at the first energization pattern switching timing, needs to be acquired in advance through experiments, simulations, or the like.

The energization pattern setting unit 60 compares the V-phase inductance change signal Zv with a predetermined second threshold value Zvth, and switches the energization pattern at the timing when the V-phase inductance change signal Zv becomes equal to or greater than the second threshold value Zvth. In the example shown in FIG. 4, the energization pattern setting unit 60 switches the energization pattern at times t3, t6, t9, and t12. Hereinafter, times t3, t6, t9, and t12 are referred to as second energization pattern switching timings. It should be noted that the second threshold value Zvth, which is the value of the V-phase inductance change signal Zv at the second energization pattern switching timing, needs to be obtained in advance through experiments, simulations, or the like.

The energization pattern setting unit 60 compares the W-phase inductance change signal Zw with a predetermined third threshold value Zwth, and switches the energization pattern at the timing when the W-phase inductance change signal Zw becomes equal to or greater than the third threshold value Zwth. In the example shown in FIG. 4, the energization pattern setting unit 60 switches the energization pattern at times t2, t5, t8, and t11. Hereinafter, times t2, t5, t8, and t11 are referred to as third energization pattern switching timings. It should be noted that the third threshold value Zwth, which is the value of the W-phase inductance change signal Zw at the third energization pattern switching timing, needs to be acquired in advance through experiments, simulations, or the like.

As shown in FIG. 4, the U-phase inductance change signal Zu, the V-phase inductance change signal Zv, and the W-phase inductance change signal Zw have a phase difference of 120 electrical degrees from each other. Looking at the total of the U-phase inductance change signal Zu, the V-phase inductance change signal Zv, and the W-phase inductance change signal Zw, one energization switching timing appears at intervals of 60 electrical degrees.

For example, assume that the energization pattern is switched to the energization pattern PA1 at time t1, which is the first energization switching timing. In this case, the energization pattern setting unit 60 switches the energization pattern to the energization pattern PA2 at the time t2 when the third threshold value Zwth, which is the third energization switching timing, appears after rotating by 60 electrical degrees from the time t1.
The energization pattern setting unit 60 switches the energization pattern to the energization pattern PA3 at the time t3 when the second threshold value Zvth, which is the second energization switching timing, appears after rotating by 60 electrical degrees from the time t2.
The energization pattern setting unit 60 switches the energization pattern to the energization pattern PA4 at the time t4 when the first threshold value Zuth, which is the first energization switching timing after rotating by 60 electrical degrees from the time t3, appears.
The energization pattern setting unit 60 switches the energization pattern to the energization pattern PA5 at the time t5 when the third threshold value Zwth, which is the third energization switching timing after rotating by 60 electrical degrees from the time t4, appears.
The energization pattern setting unit 60 switches the energization pattern to the energization pattern PA6 at the time t6 when the second threshold value Zvth, which is the second energization switching timing after rotating by 60 electrical degrees from the time t5, appears.
The energization pattern setting unit 60 switches the energization pattern to the energization pattern PA1 at time t7 when the first threshold value Zuth, which is the first energization switching timing, appears after rotating by 60 electrical degrees from time t6.
Thereafter, the energization pattern setting unit 60 repeats the same operation as the operation from time t2 to time t7.

It should be noted that the above operation is the operation when the U-phase coil, the V-phase coil, and the W-phase coil are delta-connected. When performing advance angle control, the energization pattern may be switched at a timing earlier than the energization switching timing.

The energization pattern setting unit 60 outputs the command voltage indicated by the command signal VC to the addition unit 80 while switching the energization pattern. For example, if the command signal VC is a rotation speed command signal that indicates the rotation speed, a voltage conversion unit that converts the indicated rotation speed into a command voltage may be provided before the energization pattern setting unit 60 . The high-frequency voltage applying section 70 outputs to the adding section 80 a high-frequency voltage having a frequency higher than that of the three-phase AC voltage. The addition unit 80 adds the command voltage from the energization pattern setting unit 60 and the high frequency voltage from the high frequency voltage application unit 70 and outputs the command voltage superimposed with the high frequency voltage to the PWM conversion unit 90 . The PWM converter 90 outputs a switching control signal to the drive circuit 11 based on the command voltage superimposed with the high frequency voltage.

For example, as shown in FIG. 4, when the energization pattern is switched to the energization pattern PA2 at time t2, the PWM converter 90 turns on the V-phase upper arm switch _QVH and the W-phase lower arm switch _QWL . At the same time, a switching control signal for turning off the remaining arm switches is output to the drive circuit 11 (see FIG. 2). In the case of the energization pattern PA2, the PWM converter 90 performs switching control of only the V-phase upper arm switch _QVH with a switching duty ratio corresponding to the command voltage superimposed with the high-frequency voltage. As a result, a three-phase AC voltage superimposed with a high-frequency voltage is supplied from the drive circuit 11 to the three-phase motor 20 . It should be noted that the energization pattern of the sensorless 120-degree energization method in the present embodiment is merely an example, and can be changed as appropriate according to required specifications and the like.

As described above, the control unit 13 switches the energization pattern at intervals of 60 degrees in synchronization with the energization switching timing obtained from the U-phase inductance change signal Zu, the V-phase inductance change signal Zv, and the W-phase inductance change signal Zw. By performing switching control of each arm switch, the three-phase motor 20 is controlled by a sensorless 120-degree energization method.

As described above, the motor control device 10 in the first embodiment includes the current detection unit 12 that detects the current flowing through the three-phase motor 20, the energization pattern of the three-phase motor 20 is switched at intervals of 60 degrees, and three A control unit 13 that outputs to the drive circuit 11 a switching control signal for supplying a three-phase AC voltage superimposed with a high-frequency voltage having a frequency higher than that of the phase AC voltage to the three-phase motor 20 . The control unit 13 generates an inductance change signal correlated with a change in inductance based on the detected current obtained from the current detection unit 12, and controls switching timing of the energization pattern based on the generated inductance change signal.
According to the first embodiment as described above, the motor control device 10 can control the three-phase motor 20 by the sensorless 120-degree energization method to which the HFI technology is applied, and can use a more inexpensive control circuit (control unit 13). and an electric pump device 1 are provided.

By the way, in the conventional sensorless 120-degree energization method, unless the rotation speed of the three-phase motor is equal to or higher than a predetermined rotation speed, an induced voltage that can detect the zero-crossing point is not generated. Therefore, in the conventional sensorless 120-degree energization method, forced commutation control that forcibly switches the energization pattern at a predetermined commutation frequency until the rotation speed of the three-phase motor reaches a predetermined rotation speed when the three-phase motor is started. in many cases. However, forced commutation control is vulnerable to load fluctuations because the energization pattern is forcibly switched regardless of the rotational position of the three-phase motor. In contrast, in the first embodiment, sensorless synchronous control of the three-phase motor 20 can be performed using an inductance change signal that can acquire the energization switching timing even in the low rotation range. Resistant to load fluctuations.

In the motor control device 10 of the first embodiment, the current detection unit 12 detects currents flowing through the three phases of the three-phase motor 20, and the control unit 13 detects the three-phase currents obtained from the current detection unit 12. Based on this, a three-phase inductance change signal that correlates with the three-phase inductance change is generated, and the switching timing of the energization pattern is controlled based on the three-phase inductance change signal.
As a result, the switching timing of the energization pattern is controlled based on the energization switching timing obtained at intervals of 60 degrees from the three-phase inductance change signals, so that the energization pattern can be switched at intervals of 60 degrees with high accuracy.

[Second embodiment]
Next, a second embodiment of the invention will be described.
FIG. 5 is a block diagram schematically showing an electric pump device 2 having a motor control device 10A according to a second embodiment of the invention. FIG. 6 is a functional block diagram showing each function of the control unit 13A according to the second embodiment. 5 and 6, among the components of the electric pump device 2 in the second embodiment, the same components as the components of the electric pump device 1 in the first embodiment are denoted by the same reference numerals. In the following description, among the constituent elements of the electric pump device 2 in the second embodiment, constituent elements that are different from the constituent elements of the electric pump device 1 in the first embodiment will be explained, and explanations of the same constituent elements will be omitted.

As shown in FIG. 5, the electric pump device 2 includes a motor control device 10A and an electric pump 40. The motor control device 10A includes a shunt resistor 15 as a current detection section instead of the current detection section 12 of the first embodiment. Further, the motor control device 10A includes a control section 13A instead of the control section 13 of the first embodiment.

The shunt resistor 15 is a current detector that detects current flowing through the three-phase motor 20 . The shunt resistor 15 detects current flowing through the power supply line of the drive circuit 11 via the three-phase motor 20 . In the following description, the power supply line of the drive circuit 11 may be called "bus line". One end of the shunt resistor 15 is electrically connected to each of the source terminals of the U-phase lower arm switch _QUL , the V-phase lower arm switch _QVL , and the W-phase lower arm switch _QWL . The other end of shunt resistor 15 is electrically connected to the negative terminal of DC power supply 200 . Furthermore, one end of the shunt resistor 15 is electrically connected to the controller 13A. The current flowing through the bus line flows through the shunt resistor 15 into the vehicle interior ground. Therefore, a voltage appears across the terminals of the shunt resistor 15 in proportion to the current flowing through the bus line. Such a voltage across the terminals of the shunt resistor 15 is supplied to the controller 13A as a bus line detection current Ib indicating the detection result of the current flowing through the bus line. A resistance voltage dividing circuit may be provided between one end of the shunt resistor 15 and the control section 13A, if necessary.

The control unit 13A is, for example, a microprocessor such as an MCU. A command signal VC output from a host controller (not shown) is input to the controller 13A. Further, the voltage across the terminals of the shunt resistor 15 is input to the control section 13A as the bus line detection current Ib. The control unit 13A is communicably connected to the storage unit 14 via a communication bus (not shown).

The control unit 13A supplies the three-phase motor 20 with a three-phase AC voltage in which the energization pattern of the three-phase motor 20 is switched at intervals of 60 degrees and a high-frequency voltage having a higher frequency than the frequency of the three-phase AC voltage is superimposed. The switching control signal obtained is output to the drive circuit 11 . The control unit 13A generates an inductance change signal correlated with a change in inductance of the bus line based on the bus line detection current Ib obtained from the shunt resistor 15, and determines switching timing of the energization pattern based on the generated inductance change signal. to control.

The bus line detection current Ib detected by the shunt resistor 15 contains a high frequency current having the same frequency as the high frequency voltage superimposed on the three-phase AC voltage. The control unit 13A extracts, as an extracted current, a frequency component having the same frequency as the high-frequency voltage superimposed on the three-phase AC voltage from the bus line detection current Ib obtained from the shunt resistor 15, and extracts the extracted current and the extracted current. An inductance change signal is generated by calculating the sum of squares with the phase-shifted current obtained by shifting the phase of the current by π/2. 13 A of control parts acquire a phase shift current by performing Hilbert transform with respect to an extraction current. In this embodiment, the Hilbert transform is performed by an FIR filter.

As shown in FIG. 6, the control unit 13A has an inductance change signal generation unit 50A and an energization pattern setting unit 60A instead of the inductance change signal generation unit 50 and the energization pattern setting unit 60 of the first embodiment.

The inductance change signal generation unit 50A generates a bus line inductance change signal that correlates with the change in inductance of the bus line based on the bus line detection current Ib obtained from the shunt resistor 15 . The inductance change signal generation unit 50A has a BPF 51A, a Hilbert transform unit 54A, and a sum-of-squares square root operation unit 57A.

The BPF 51A extracts a frequency component having the same frequency as the high-frequency voltage superimposed on the three-phase AC voltage from the bus line detection current Ib obtained from the shunt resistor 15 as a bus line extraction current Ibh. Ibh is output to the Hilbert transform unit 54A.

The Hilbert transform unit 54A transforms the bus line extracted current Ibh into a complex analytic signal having a real part Xb and an imaginary part Yb. The real part Xb is the same as the bus line extraction current Ibh. The imaginary part Yb is obtained by the Hilbert transform performed by the FIR filter. The imaginary part Yb is a phase-shifted current obtained by shifting the phase of the bus line extracted current Ibh by π/2. The Hilbert transform unit 54A outputs the real part Xb and the imaginary part Yb to the root-sum-of-squares operation unit 57A.

Root-sum-of-square calculator 57A calculates the square root of the sum of squares of real part Xb and imaginary part Yb obtained from Hilbert transform part 54A, thereby calculating bus line inductance change signal Zb that correlates with the change in inductance of the bus line. . In other words, the square-sum-square calculator 57A calculates the square-root sum of the squares of the bus line extracted current Ibh and the phase-shifted current obtained by shifting the phase of the bus line extracted current Ibh by π/2 to obtain the bus line inductance. A change signal Zb is calculated. Root-sum-of-squares operation unit 57A outputs bus line inductance change signal Zb to energization pattern setting unit 60A.

The energization pattern setting unit 60A switches the energization pattern based on the bus line inductance change signal Zb. FIG. 7 is a timing chart showing temporal correspondences between the U-phase inductance change signal Zu, the V-phase inductance change signal Zv, the W-phase inductance change signal Zw, the bus line inductance change signal Zb, and the energization pattern.

As shown in FIG. 7, the energization pattern setting unit 60A compares the bus line inductance change signal Zb with a predetermined fourth threshold value Zbth, and sets the energization pattern at the timing when the bus line inductance change signal Zb becomes equal to or greater than the fourth threshold value Zbth. switch. In the example shown in FIG. 7, the energization pattern setting unit 60A switches the energization pattern each from time t1 to time t13. Hereinafter, the period from time t1 to time t13 will be referred to as energization pattern switching timing. It should be noted that the fourth threshold value Zbth, which is the value of the bus line inductance change signal Zb at the energization pattern switching timing, needs to be acquired in advance through experiments, simulations, or the like.

As shown in FIG. 7, one energization switching timing appears in the bus line inductance change signal Zb at an electrical angle interval of 60 degrees.

For example, assume that the energization pattern is switched to the energization pattern PA1 at time t1. In this case, the energization pattern setting unit 60A switches the energization pattern to the energization pattern PA2 at the time t2 when the fourth threshold value Zbth, which is the energization switching timing after rotating by 60 electrical degrees from the time t1, appears.
The energization pattern setting unit 60A switches the energization pattern to the energization pattern PA3 at the time t3 when the fourth threshold value Zbth, which is the energization switching timing after rotating by 60 electrical degrees from the time t2, appears.
The energization pattern setting unit 60A switches the energization pattern to the energization pattern PA4 at the time t4 when the fourth threshold value Zbth, which is the energization switching timing after rotating by 60 electrical degrees from the time t3, appears.
The energization pattern setting unit 60A switches the energization pattern to the energization pattern PA5 at time t5 when the fourth threshold value Zbth, which is the energization switching timing after rotating by 60 electrical degrees from time t4, appears.
The energization pattern setting unit 60A switches the energization pattern to the energization pattern PA6 at the time t6 when the fourth threshold value Zbth, which is the energization switching timing after rotating by 60 electrical degrees from the time t5, appears.
The energization pattern setting unit 60A switches the energization pattern to the energization pattern PA1 at the time t7 when the fourth threshold value Zbth, which is the energization switching timing after rotating by 60 electrical degrees from the time t6, appears.
Thereafter, the energization pattern setting unit 60A repeats the same operation as the operation from time t2 to time t7.

The energization pattern setting unit 60A outputs the command voltage indicated by the command signal VC to the adding unit 80 while switching the energization pattern. As in the first embodiment, for example, when the command signal VC is a rotation speed command signal that indicates the rotation speed, a voltage for converting the indicated rotation speed into a command voltage is provided in the preceding stage of the energization pattern setting unit 60A. A converter may be provided. The high-frequency voltage applying section 70 outputs to the adding section 80 a high-frequency voltage having a frequency higher than that of the three-phase AC voltage. The addition unit 80 adds the command voltage from the energization pattern setting unit 60 and the high frequency voltage from the high frequency voltage application unit 70 and outputs the command voltage superimposed with the high frequency voltage to the PWM conversion unit 90 . The PWM converter 90 outputs a switching control signal to the drive circuit 11 based on the command voltage superimposed with the high frequency voltage.

For example, as shown in FIG. 7, when the energization pattern is switched to the energization pattern PA2 at time t2, the PWM converter 90 turns on the V-phase upper arm switch _QVH and the W-phase lower arm switch _QWL . At the same time, a switching control signal for turning off the remaining arm switches is output to the drive circuit 11 (see FIG. 2). In the case of the energization pattern PA2, the PWM converter 90 performs switching control of only the V-phase upper arm switch _QVH with a switching duty ratio corresponding to the command voltage superimposed with the high-frequency voltage. As a result, a three-phase AC voltage superimposed with a high-frequency voltage is supplied from the drive circuit 11 to the three-phase motor 20 . It should be noted that the energization pattern of the sensorless 120-degree energization method in the present embodiment is merely an example, and can be changed as appropriate according to required specifications and the like.

As described above, the control unit 13A switches the energization pattern at intervals of 60 degrees in synchronization with the energization switching timing obtained from the bus line inductance change signal Zb, and controls the switching of each arm switch. is controlled by a sensorless 120-degree energization method.

As described above, the motor control device 10A in the second embodiment includes the shunt resistor 15 that detects the current flowing through the three-phase motor 20, the energization pattern of the three-phase motor 20 is switched at intervals of 60 degrees, and three A control unit 13A that outputs to the drive circuit 11 a switching control signal for supplying a three-phase AC voltage superimposed with a high-frequency voltage having a frequency higher than that of the phase AC voltage to the three-phase motor 20. The control unit 13A generates an inductance change signal correlated with a change in inductance based on the detected current obtained from the shunt resistor 15, and controls switching timing of the energization pattern based on the generated inductance change signal.
According to the second embodiment, similarly to the first embodiment, the three-phase motor 20 can be controlled by the sensorless 120-degree energization method to which the HFI technology is applied, and a more inexpensive control circuit (control unit 13A) A motor control device 10A and an electric pump device 2 are provided. Further, as in the first embodiment, in the second embodiment, sensorless synchronous control of the three-phase motor 20 can be performed using an inductance change signal that can acquire the energization switching timing even in the low speed range. Resistant to load fluctuations during phase motor start-up.

In addition, in the motor control device 10A of the second embodiment, the shunt resistor 15 detects the current flowing through the power supply line of the drive circuit 11 via the three-phase motor 20, and the control section 13A detects the An inductance change signal correlated with a change in the inductance of the power supply line is generated based on the detected current of the power supply line, and the switching timing of the energization pattern is controlled based on the inductance change signal of the power supply line.
As a result, the switching timing of the energization pattern is controlled based on the energization switching timing obtained at intervals of 60 degrees from the inductance change signal of the power supply line. Since the energization pattern can be switched by the inductance change signal, the calculation load of the controller 13A can be further reduced as compared with the first embodiment.

[Modification]
The present invention is not limited to the above-described embodiments, and each configuration described in this specification can be appropriately combined within a mutually consistent range.
For example, in the low rotation range when the three-phase motor 20 is started, the three-phase motor 20 is controlled by the sensorless 120-degree energization method described in the above embodiment, and the rotation speed of the three-phase motor 20 can detect the zero cross point. The three-phase motor 20 may be controlled by a conventional sensorless 120-degree energization method in which the energization pattern is switched based on the detection result of the zero-crossing point after reaching the rotational speed at which the induced voltage is generated.

In the first embodiment, the U-phase current sensor 12u, the V-phase current sensor 12v, and the W-phase current sensor 12w are CT-type current sensors, but the present invention is not limited to this. A shunt resistor provided between the lower arm switch and the ground may be used as a current sensor for detecting the current of each phase.

In the second embodiment, the shunt resistor 15 is used as a current sensor for detecting the current flowing in the power supply line of the drive circuit 11. However, the present invention is not limited to this, and the shunt resistor 15 is replaced with A CT-type current sensor may also be used. When a CT-type current sensor is used, a CT-type current sensor may be provided on the low-voltage power supply line of the drive circuit 11, or a CT-type current sensor may be provided on the high-voltage power supply line of the drive circuit 11. may be provided.

In the above embodiment, an electric pump device that supplies cooling oil F to a drive motor mounted on a hybrid vehicle was exemplified as the electric pump device of the present invention, but the electric pump device of the present invention is not limited to this. For example, the present invention can be applied to an electric pump device for supplying oil to a transmission. Further, the fluid discharged from the electric pump is not limited to oil such as cooling oil. Moreover, the motor control device of the present invention can be applied not only to control the motor of the electric pump, but also to general applications using the motor.

1, 2... Electric pump device, 10, 10A... Motor control device, 11... Drive circuit, 12u... U-phase current sensor (current detection unit), 12v... V-phase current sensor (current detection unit), 12w... W-phase current Sensor (current detection unit) 13, 13A control unit 14 storage unit 15 shunt resistor (current detection unit) 20 three-phase motor 21 shaft (rotating shaft) 22u U-phase terminal 22v... V-phase terminal, 22w... W-phase terminal, 30... Pump, 31... Oil suction port, 32... Oil discharge port, 40... Electric pump, 50, 50A... Inductance change signal generator, 51... First BPF, 52... Second BPF, 53... Third BPF, 54... First Hilbert transform unit, 55... Second Hilbert transform unit, 56... Third Hilbert transform unit, 57... First root sum square calculation Section 58... Second root-sum-of-squares calculator 59... Third root-sum-of-squares calculator 51A...BPF 54A... Hilbert transform section 57A... Square-root-sum-of-

squares calculator

60, 60A... Conducting pattern setting section , 70... High-frequency voltage application unit, 80... Addition unit, 90... PWM conversion unit, 200... DC power supply, F... Cooling oil

Claims

A motor control device for controlling a three-phase motor having saliency by a sensorless 120-degree energization method,
a drive circuit that converts a DC power supply voltage into a three-phase AC voltage and supplies the voltage to the three-phase motor;
a current detection unit that detects a current flowing through the three-phase motor;
Switching in which the energization pattern of the three-phase motor is switched at intervals of 60 degrees, and the three-phase AC voltage superimposed with a high-frequency voltage having a frequency higher than that of the three-phase AC voltage is supplied to the three-phase motor. a control unit that outputs a control signal to the drive circuit;
with
The control unit generates an inductance change signal that correlates with a change in inductance based on the detected current obtained from the current detection unit, and controls switching timing of the energization pattern based on the inductance change signal.
motor controller.
The current detection unit detects a current flowing through the three phases of the three-phase motor,
The control unit generates a three-phase inductance change signal correlated with the three-phase inductance change based on the three-phase detected current obtained from the current detection unit, and generates a three-phase inductance change signal based on the three-phase inductance change signal. 2. The motor control device according to claim 1, wherein a switching timing of the energization pattern is controlled by a control.
The current detection unit detects a current flowing through the power supply line of the drive circuit via the three-phase motor,
The control unit generates an inductance change signal correlated with a change in inductance of the power supply line based on the detected current of the power supply line obtained from the current detection unit, and the current is supplied based on the inductance change signal of the power supply line. 2. The motor control device according to claim 1, which controls pattern switching timing.
The control section extracts a frequency component having the same frequency as that of the high-frequency voltage as an extracted current from the detected current obtained from the current detecting section, and shifts the phase of the extracted current and the extracted current by π/2. 4. The motor controller according to any one of claims 1 to 3, wherein the inductance change signal is generated by calculating the sum of squares with the phase shift current.
The motor control device according to claim 4, wherein the control unit obtains the phase-shifted current by performing a Hilbert transform on the extracted current.
The motor control device according to claim 5, wherein the Hilbert transform is performed by an FIR filter.
a three-phase motor with saliency;
a pump positioned on one axial side of the rotating shaft of the three-phase motor and driven by the three-phase motor via the rotating shaft to discharge a fluid;
The motor control device according to any one of claims 1 to 6, which controls the three-phase motor by a sensorless 120-degree energization method;
An electric pump device comprising: