JP2016197933A - Motor control apparatus and motor control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor control apparatus and motor control method, capable of achieving little motor loss and motor cost reduction.SOLUTION: The motor control apparatus detects a component with a percentage modulation (M) of PWM control of an inverter (100) provided with a plurality of semiconductor elements (120) for power and driving a motor (200) by PWM control, determines a percentage modulation on the basis of any of the components (V1, V2, N1, T1, I1) and sets a carrier frequency of PWM control to become higher as the percentage modulation is higher in order to reduce motor loss.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a motor control apparatus and a motor control method including an inverter that includes a plurality of power semiconductor elements and that drives a motor by PWM control.

  Recently, vehicles equipped with an electric power train such as a hybrid vehicle (hereinafter referred to as HEV) and a plug-in hybrid vehicle (hereinafter referred to as PHEV) have become widespread. These automobiles are additionally equipped with a motor for propelling the vehicle and an inverter for driving the vehicle in addition to the configuration of a conventional gasoline engine vehicle, and technological development is progressing to improve fuel consumption and electricity consumption. For example, as a means for reducing the motor loss, there is a technique of changing the carrier frequency of the inverter so that the total loss obtained by adding the motor loss and the inverter loss is minimized (see, for example, Patent Document 1).

Apart from this, there are strict requirements for cost reduction and miniaturization of motors and inverters. Regarding cost reduction, in recent years, with the spread of HEV and PHEV, cost reduction of an inverter made of a conventional Si semiconductor material is progressing. Further, the inverter loss can be further reduced by an inverter made of a low-loss non-Si semiconductor material (SiC, GaN, etc.).
On the other hand, the main materials for motors are iron, copper, and rare earths, and the cost reduction has not remarkably advanced.

  In order to reduce the cost of the motor, it is essential to reduce the size of the motor. For example, if the motor loss can be reduced, the motor cooling structure can be reduced in size and simplified, and the cost can be reduced.

Japanese Patent No. 4605274

In the technique described in Patent Document 1 above, since the inverter carrier frequency is set so that the total loss obtained by adding the motor loss and the inverter loss is minimized, the motor loss reduction effect is not sufficient. There is a problem that cost reduction due to reduction in size and simplification of the motor cooling device due to the reduction is not sufficient.
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a motor control device and a motor control method that can reduce motor loss and reduce the cost of the motor.

In order to achieve the above object, a motor control device according to the present invention includes an inverter that includes a plurality of power semiconductor elements and drives a motor by PWM control, and a detection unit that detects components of a modulation factor of the PWM control. And a modulation rate determination unit that determines a modulation rate based on the components,
In order to reduce motor loss, a carrier frequency setting unit that sets the carrier frequency of the PWM control higher as the modulation rate is higher is provided.

  In order to achieve the above object, according to the present invention, a component of a PWM control modulation factor of an inverter that includes a plurality of power semiconductor elements and drives a motor by PWM control is detected, and the modulation factor is determined based on the component. In order to reduce motor loss, a motor control method is provided in which the carrier frequency of the PWM control is set higher as the modulation factor is higher.

  According to the present invention, when the modulation rate is high, the carrier frequency is changed to a higher value according to the modulation rate when the motor is driven by PWM control, so that the motor loss can be reduced, thereby reducing the size of the motor cooling device. Can be simplified and simplified, and the cost of the motor can be reduced.

It is a block diagram which shows the structural example of the motor control apparatus which concerns on Embodiment 1 of this invention. It is the graph which showed the relationship with the carrier frequency of the motor loss and inverter loss in the motor control apparatus which concerns on each embodiment of this invention. It is the graph which showed the relationship between the modulation factor at the time of driving the motor in the motor control apparatus which concerns on each embodiment of this invention, and the motor loss depending on a carrier frequency. It is the graph which showed the relationship between the modulation factor at the time of driving the motor in the motor control apparatus which concerns on each embodiment of this invention, and the setting value of a carrier frequency. It is the graph which showed the state which provided the lower limit and the upper limit in the relationship between the modulation factor at the time of driving the motor in the motor control apparatus which concerns on each embodiment of this invention, and the setting value of a carrier frequency. It is a flowchart which shows the setting method of the carrier frequency of the inverter in the motor control apparatus which concerns on Embodiment 1 of this invention. It is a block diagram which shows the structural example of the motor control apparatus which concerns on Embodiment 2 of this invention. It is a flowchart which shows the setting method of the carrier frequency of the inverter in the motor control apparatus which concerns on Embodiment 2 of this invention. It is the graph which showed the relationship between the cooling water temperature (or motor winding temperature in Embodiment 4) and the correction coefficient in the motor control apparatus which concerns on Embodiment 2 of this invention. It is the graph which showed the relationship between the cooling water temperature (or motor winding temperature in Embodiment 4) in the motor control apparatus which concerns on Embodiment 2 of this invention, and another correction coefficient. It is the graph which showed the relationship between the cooling water temperature (or motor winding temperature in Embodiment 4) in the motor control apparatus which concerns on Embodiment 2 of this invention, and another correction coefficient. It is a block diagram which shows the structural example of the motor control apparatus which concerns on Embodiment 3 of this invention. It is a flowchart which shows the setting method of the carrier frequency of the inverter in the motor control apparatus which concerns on Embodiment 3 of this invention. It is the graph which showed the relationship between the inverter input voltage and the correction coefficient in the motor control apparatus which concerns on Embodiment 3 of this invention. It is the graph which showed the relationship between the inverter input voltage in the motor control apparatus which concerns on Embodiment 3 of this invention, and another correction coefficient. It is the graph which showed the relationship between the inverter input voltage in the motor control apparatus which concerns on Embodiment 3 of this invention, and another correction coefficient. It is a block diagram which shows the structural example of the motor control apparatus which concerns on Embodiment 4 of this invention. It is a flowchart which shows the setting method of the carrier frequency of the inverter in the motor control apparatus which concerns on Embodiment 4 of this invention. It is a map data figure which shows the modulation factor according to the torque command value and motor rotation speed of the motor in the motor control apparatus which concerns on Embodiment 4 of this invention. It is a map data figure which shows the modulation factor according to the phase electric current and motor rotation speed in the motor control apparatus which concerns on Embodiment 4 of this invention.

  Embodiments of a motor control device according to the present invention will be described below with reference to the accompanying drawings.

Embodiment 1 FIG.
First, a motor control device according to Embodiment 1 of the present invention will be described with reference to FIG. Reference numeral 200 denotes a power running / regeneration motor such as a permanent magnet AC synchronous motor, 300 denotes a chargeable / dischargeable power storage device such as a lithium ion battery, nickel hydride battery, and electric double layer capacitor, and 100 denotes an electric motor during power running. An inverter that converts power supplied from DC to AC and converts the regenerative power of the motor from AC to DC during regeneration, 120 is a voltage-driven power semiconductor element such as an IGBT or MOSFET, and 130 is a power semiconductor A diode connected in antiparallel to the element, 140 is a control circuit for switching control of the power semiconductor element, and 150 is a smoothing capacitor for removing the ripple on the bus.

  Reference numeral 400 denotes a voltage sensor that detects a line voltage of the motor 200, and 401 denotes a voltage sensor that detects a terminal voltage on the power storage device 300 side of the inverter 100. Reference numeral 500 denotes a modulation factor calculation unit that calculates a modulation factor based on the voltages detected by the voltage sensors 400 and 401. Reference numeral 600 denotes a PWM (Pulse Width Modulation: pulse width) based on the modulation factor calculated by the modulation factor calculator 500. It is a carrier frequency setting unit for setting a carrier frequency for modulation control.

Next, a relationship between the total loss obtained by adding the motor loss generated in the motor 200 and the inverter loss generated in the inverter 100 and the carrier frequency of the inverter 100 will be described.
When the motor 200 is driven by the inverter 100 by PWM control, a current waveform (not shown) flowing through the winding of the motor 200 is not an ideal sine wave, and a harmonic component generated by the switching operation of the inverter 100 is superimposed.

  The harmonic component depends on the carrier frequency of the inverter 100, the inductance in the winding of the motor 200, the modulation factor, and the like. As shown in FIG. 2, when the carrier frequency of the inverter 100 is increased, the inverter loss increases because the switching loss increases. As for the motor loss, when the carrier frequency of the inverter 100 is increased, the harmonic component is reduced, and the effective value in the entire waveform is reduced, so that the motor loss is reduced.

  With respect to the total loss obtained by adding the motor loss and the inverter loss, the total loss decreases as the carrier frequency increases when the carrier frequency of the inverter 100 is less than fc_a, and the total loss increases as the carrier frequency increases when the carrier frequency of the inverter 100 is fc_a or higher. It tends to increase. That is, if the carrier frequency of the inverter 100 is fc_a, the total loss can be reduced.

  In the conventional method such as Patent Document 1 described above, the carrier frequency that minimizes the total loss for each motor speed and torque is derived by experiment and calculation, and the optimum carrier frequency map data for the motor speed and torque is obtained. Was previously stored in a controller (not shown).

However, when this method is adopted, it is necessary to perform experiments and calculations for each rotation speed and torque of the motor, resulting in a huge man-hour.
In the present embodiment, the total loss is reduced by using the relationship between the modulation factor when driving the motor shown in FIG. 3 and the motor loss depending on the carrier frequency, which will be described below.

FIG. 3 shows an example of the relationship between the modulation factor when driving the motor and the motor loss depending on the carrier frequency. As shown in the figure, the higher the modulation factor when driving the motor, the higher the harmonic component and the motor loss. When the carrier frequency is low, the motor loss tends to be larger than when the carrier frequency is high.
For this reason, when the modulation rate at the time of driving the motor is high, it is effective to increase the carrier frequency according to the modulation rate and reduce the motor loss as shown in FIG. 4, for example.

  However, as shown in FIG. 2, if the carrier frequency is increased, the inverter loss increases. Therefore, for example, as shown in FIG. 5, an upper limit fc_max is preferably provided for the carrier frequency so that the total loss does not increase. As a method of setting the upper limit fc_max of the carrier frequency, for example, the inverter loss for each carrier frequency is estimated based on the detected value from the rotational speed and torque of the motor, various sensors (current sensor, voltage sensor, temperature sensor) and the like. There is a method of setting the carrier frequency at which the inverter loss is a predetermined value or less as the upper limit fc_max of the carrier frequency.

In addition, if the carrier frequency is too low, the operation of the motor becomes unstable and noise becomes a problem. For example, it is preferable to provide a lower limit fc_min of the carrier frequency as shown in FIG.
The above-described FIGS. 2 to 5 are concepts common to the embodiments of the present invention.

Next, variable processing of the carrier frequency according to the modulation rate when driving the motor according to Embodiment 1 of the present invention will be described using the flowchart of FIG.
In step S601, the terminal voltage V1 on the power storage device 300 side of the inverter 100 detected by the voltage sensor 401 is acquired.
In step S602, the line voltage V2 of the motor 200 detected by the voltage sensor 400 is acquired.
These voltages V1 and V2 are components of the modulation rate in the present invention.

In step S603, using the V1 and V2 obtained in steps S601 and S602, respectively, for example, the modulation factor M is calculated as shown in the following equation (1).
M = V2 / (V1 × 0.612)... Formula (1)

In step S604, the carrier frequency setting unit 602 that has received the modulation factor M derived in step S603 from the modulation factor calculation unit 500 transmits a signal for setting the carrier frequency in accordance with the relationship shown in FIG. 4 or FIG. 140. Since details of FIGS. 4 and 5 have been described above, description thereof is omitted here.
In step S605, the control circuit 140 that has received the drive signal having the carrier frequency set in step S604 performs switching control of the power semiconductor element 120.
According to the first embodiment described above, the total loss of the motor loss and the inverter loss can be reduced by performing the variable processing of the carrier frequency according to the modulation rate.

Embodiment 2. FIG.
A motor control apparatus according to Embodiment 2 of the present invention will be described with reference to FIG. Reference numeral 200 denotes a power running / regeneration motor such as a permanent magnet AC synchronous motor, 300 denotes a chargeable / dischargeable power storage device such as a lithium ion battery, nickel metal hydride battery, and electric double layer capacitor, and 100 denotes an electric motor during power running. An inverter that converts supply power from direct current to alternating current and converts the regenerative power of the motor from alternating current to direct current during regeneration, 120 is a voltage-driven power semiconductor element such as an IGBT or MOSFET, and 130 is a power semiconductor element A diode connected in antiparallel, 140 is a control circuit for switching control of the power semiconductor element, and 150 is a smoothing capacitor for removing ripples on the bus.

700 is a motor cooling device such as a water cooling device or an oil cooling device, 400 is a voltage sensor that detects the line voltage of the motor 200, and 401 is a voltage that detects the terminal voltage on the power storage device side of the inverter 100. A sensor 405 is mounted on the cooling device 700 of the motor 200 and detects the temperature of a coolant such as cooling water or cooling oil. A modulation 500 calculates a modulation factor based on the voltages detected by the voltage sensors 400 and 401. A rate calculation unit 602 sets a carrier frequency for PWM control based on the modulation rate calculated by the modulation rate calculation unit 500 and corrects the carrier frequency based on the winding temperature of the motor 200 detected by the temperature sensor 405. It is a carrier frequency setting part.
The temperature sensor 405 is provided on the outlet side of the cooling device 700, but may be provided on the inlet side.

Next, a variable process of the carrier frequency according to the modulation rate when driving the motor according to the second embodiment of the present invention will be described using the flowchart of FIG. Steps S1501 to S1503 are the same as steps S601 to S603 in FIG.
In step S1504, the coolant temperature F1 on the coolant channel outlet side of the cooling device 700 detected by the temperature sensor 405 is acquired.
In the case where the temperature sensor is provided on both the outlet side and the inlet side of the cooling device 700, the temperature difference between the two sensors may be the cooling water temperature F1.

In step S1505, the correction coefficient K is derived from the coolant temperature F1 acquired in step S1504. For example, as shown in FIG. 9, the correction coefficient K is set such that the correction coefficient K increases as the cooling water temperature F1 increases. The reason is that if the cooling water temperature F1 is high, it is assumed that the motor loss is high. Therefore, the carrier frequency set based on the modulation factor M derived in step S1503 is multiplied or added by the correction coefficient K. This is because the loss due to the harmonic component of the motor is reduced by setting a higher carrier frequency.
Here, as to how to determine the correction coefficient K, as shown in FIGS. 10 and 11, the correction coefficient K may be increased when the coolant temperature F1 is higher than a predetermined value.

  In step S1506, the carrier frequency setting unit 602 outputs the drive signal having the carrier frequency set in step S1505 to the control circuit 140 that controls the switching of the power semiconductor element 120.

In the above description, the motor cooling device 700 is a water-cooled cooling device. However, oil may be used as a refrigerant, and this may be used as an oil-cooled cooling device.
According to the second embodiment described above, the total loss of the motor loss and the inverter loss can be reduced by performing the variable processing of the carrier frequency according to the modulation rate.

Embodiment 3 FIG.
A motor control apparatus according to Embodiment 3 of the present invention will be described with reference to FIG. 200 is a power running / regeneration motor such as a permanent magnet AC synchronous motor, 300 is a chargeable / dischargeable power storage device such as a lithium ion battery, nickel metal hydride battery, and electric double layer capacitor, and 100 is supplied to an electric motor during power running. An inverter that converts electric power from direct current to alternating current and converts the regenerative power of the motor from alternating current to direct current during regeneration, 120 is a voltage-driven power semiconductor element such as an IGBT or MOSFET, and 130 is reverse to the power semiconductor element. A diode connected in parallel, 140 is a control circuit that controls switching of the power semiconductor element, and 150 is a smoothing capacitor for removing ripples on the bus.

  Reference numeral 400 denotes a voltage sensor that detects a line voltage of the motor 200, and 401 denotes a voltage sensor that detects a terminal voltage on the power storage device side of the inverter 100. 500 is a modulation factor calculation unit that calculates the modulation factor based on the voltages detected by the voltage sensors 400 and 401, 603 sets a carrier frequency for PWM control based on the modulation factor calculated by the modulation factor calculation unit 500, and The carrier frequency setting unit corrects the carrier frequency based on the voltage detected by the voltage sensor 401.

  Next, the carrier frequency variable process according to the modulation rate when driving the motor according to the third embodiment will be described with reference to the flowchart of FIG. Steps S1701 to S1703 are the same processes as steps S601 to S603, respectively, and thus description thereof is omitted.

  In step S1704, the correction coefficient K is derived from the voltage V1 acquired in step S1702. For example, as illustrated in FIG. 14, the correction coefficient K is set such that the correction coefficient K increases as the inverter input voltage V1 decreases. The reason is that, in the case of the same operating point (motor torque, rotation speed) and common-mode current, if the inverter input voltage V1 is low, the motor line voltage becomes high, so that the modulation rate becomes large and the motor loss is high. It is to be done. In order to reduce the loss due to the harmonic components of the motor by multiplying or adding the correction coefficient K to the carrier frequency set based on the modulation factor M derived in step S1703 and setting it to a higher carrier frequency. is there.

Here, the correction coefficient K may be determined by increasing the correction coefficient K when the inverter input voltage V1 is smaller than a predetermined value as shown in FIGS.
In step S1705, the drive signal having the carrier frequency set in step S1704 is output to the control circuit 140 that performs switching control of the power semiconductor element.

Inverter input voltage V <b> 1 varies depending on the state of charge of power storage device 300 and a voltage drop due to internal resistance. Even when a converter that steps up and down the voltage of power storage device 300 is connected between power storage device 300 and inverter 100, inverter input voltage V1 fluctuates. is there.
According to the third embodiment described above, the total loss of the motor loss and the inverter loss can be reduced by performing the carrier frequency variable process according to the modulation rate.

Embodiment 4 FIG.
A motor control apparatus according to Embodiment 4 of the present invention will be described with reference to FIG. Reference numeral 200 denotes a power running / regeneration motor such as a permanent magnet AC synchronous motor or a field winding synchronous motor. Reference numeral 300 denotes a chargeable / dischargeable power storage such as a lithium ion battery, a nickel metal hydride battery, or an electric double layer capacitor. The apparatus, 100 is an inverter that converts electric power supplied to the motor from direct current to alternating current during power running, and the regenerative power of the motor is converted from alternating current to direct current during regeneration, and 120 is a voltage-driven power semiconductor element such as an IGBT or MOSFET , 130 is a diode connected in reverse parallel to the power semiconductor element, 140 is a control circuit for switching control of the power semiconductor element, and 150 is a smoothing capacitor for removing ripples on the bus.

  Reference numeral 402 denotes a rotational speed sensor that detects the rotational speed of the motor. Reference numeral 403 denotes, for example, a stator winding. When the motor is a field winding type synchronous motor, the winding of the motor 200 such as a field winding or a rotor winding. A temperature sensor 404 detects the temperature of the current, and a current sensor 404 detects the phase current of the motor 200. Reference numeral 501 denotes a modulation rate estimation unit that estimates a modulation rate based on at least the rotation speed detected by the rotation speed sensor 402, a torque command value from a host controller (not shown), or a phase current detected by the current sensor 404, and 600 denotes This is a carrier frequency setting unit that sets a carrier frequency for PWM control based on the modulation factor estimated by the modulation factor estimation unit 501 and corrects the carrier frequency based on the winding temperature of the motor 200 detected by the temperature sensor 403. .

  Next, the carrier frequency variable process according to the modulation rate when driving the motor in the motor control apparatus according to Embodiment 4 of the present invention will be described with reference to the flowchart of FIG.

In step S801, the rotational speed N1 of the motor 200 detected by the rotational speed sensor 402 is acquired.
In step S802, a torque command value T1 from a host controller (not shown) is acquired.
In step S803, the phase current I1 of the motor 200 detected by the current sensor 404 is acquired.
These N1, T1, and I1 are components of the modulation rate in the present invention.

  In step S804, using the motor rotation speed N1 and the torque command value T1 acquired in steps S801 and S802, respectively, for example, using the map data corresponding to the motor torque and rotation speed as shown in FIG. Is estimated. The modulation factors M11 to M33 in FIG. 19 are set by calculating in advance the modulation factor at each operating point (motor torque, rotation speed) from the characteristics of the motor. Further, since there is a correlation between the motor torque and the phase current, the motor phase current and the rotational speed as shown in FIG. 20, for example, are obtained by using the motor rotational speed N1 and the motor phase current I1 acquired in steps S801 and S803, respectively. The modulation factor M may be estimated using the corresponding map data.

  In FIGS. 19 and 20, the modulation rate is discretely set using map data, but may be set continuously. In this case, since it is difficult to use map data, for example, means for calculating and calculating the modulation rate based on N1, T1, and I1 acquired in steps S801, S802, and S803, respectively, can be considered.

In step S805, the motor winding temperature F1 detected by the temperature sensor 403 is acquired.
In step S806, a correction coefficient K is derived from the motor winding temperature F1 acquired in step S805. For example, as shown in FIG. 9 described above, the correction coefficient K is set such that the correction coefficient K increases as the motor winding temperature F2 increases. The reason is that if the motor winding temperature is high, the motor loss is assumed to be high, so the carrier frequency set based on the modulation factor M derived in step S804 is multiplied by the correction coefficient K, This is because the loss due to the harmonic component of the motor is reduced by setting the carrier frequency higher.

Here, as to how to determine the correction coefficient K, as shown in FIGS. 10 and 11, the correction coefficient K may be increased when the motor winding temperature F2 is higher than a predetermined value.
In step S807, the drive signal having the carrier frequency set in step S806 is output to the control circuit 140 that controls the switching of the power semiconductor element.

Here, in the description of step S804, for example, map data corresponding to the torque and the rotational speed of the motor as shown in FIG. 19 using the motor rotational speed N1 and the torque command value T1 acquired in steps S801 and S802, respectively. However, the modulation factor M may be estimated from only the motor rotation speed N1, only the motor torque command value T1, or only the motor phase current I1. Although not shown, it is possible to estimate the motor torque from the motor phase current and estimate the modulation factor M from the estimated motor torque.
According to the first embodiment described above, the total loss of the motor loss and the inverter loss can be reduced by performing the variable processing of the carrier frequency according to the modulation rate.

  In the first to fourth embodiments described above, the inverter made of the Si semiconductor material has been described. However, the inverter may be made of a non-Si semiconductor material having a wider band gap than silicon, and the non-Si semiconductor material is carbonized. Any of silicon, a gallium nitride-based material, or diamond may be used. By using the non-Si semiconductor material, the carrier frequency can be increased, and the total loss obtained by adding the motor loss and the inverter loss can be further reduced.

  100 inverter, 120 power semiconductor element, 130 diode, 140 control circuit, 150 smoothing capacitor, 200 motor, 300 power storage device, 400-401 voltage sensor, 402 rotation speed sensor, 403, 405 temperature sensor, 404 current sensor, 500 modulation Rate calculation unit, 501 Modulation rate estimation unit, 600 to 603 Carrier frequency setting unit, 700 Cooling device.

In order to achieve the above object, a motor control device according to the present invention includes an inverter that includes a plurality of power semiconductor elements and drives a motor by PWM control, and a detection unit that detects components of a modulation factor of the PWM control. A modulation rate determination unit that determines a modulation rate based on the components, a carrier frequency setting unit that sets a higher carrier frequency for the PWM control as the modulation rate is higher, in order to reduce motor loss, and the motor And a temperature sensor that is attached to the cooling device and detects the temperature of the refrigerant, and the carrier frequency setting unit receives a detection value of the temperature sensor and receives the temperature of the refrigerant. The carrier frequency is corrected such that the higher the is, the higher the carrier frequency is set .
In order to achieve the above object, in the present invention, a plurality of power semiconductor elements are mounted, an inverter that drives a motor by PWM control, a detection unit that detects a component of a modulation factor of the PWM control, A modulation rate determination unit that determines a modulation rate based on the components; a carrier frequency setting unit that sets the carrier frequency of the PWM control higher as the modulation rate is higher in order to reduce motor loss; and a winding of the motor A temperature sensor that detects the temperature, and the carrier frequency setting unit receives the detection value of the temperature sensor and corrects the carrier frequency so that the higher the winding temperature, the higher the carrier frequency is set. A motor control device is provided.
Furthermore, in order to achieve the above object, in the present invention, an inverter in which a plurality of power semiconductor elements are mounted and drives a motor by PWM control, a detection unit that detects a component of a modulation factor of the PWM control, A modulation rate determination unit that determines a modulation rate based on a component; and a carrier frequency setting unit that sets a higher carrier frequency of the PWM control as the modulation rate is higher in order to reduce motor loss, and the detection unit Comprises a first voltage sensor that detects a line voltage of the motor that is a component of the modulation factor, and a second voltage sensor that detects an input voltage of the inverter that is a component of the modulation factor. In addition, a motor control device is provided in which the modulation factor determination unit calculates the modulation factor based on detection values of the first and second voltage sensors.

In order to achieve the above object, according to the present invention, a component of a PWM control modulation factor of an inverter that includes a plurality of power semiconductor elements and drives a motor by PWM control is detected, and the modulation factor is determined based on the component. In order to reduce motor loss, the higher the modulation rate, the higher the carrier frequency of the PWM control, and the temperature at which the temperature of the refrigerant is detected by being attached to a cooling device that cools the motor with the refrigerant. A motor control method is provided that receives the detection value of the sensor and corrects the carrier frequency so that the carrier frequency is set higher as the temperature of the refrigerant is higher .
Furthermore, in order to achieve the above object, in the present invention, a component of a modulation rate of PWM control of an inverter in which a plurality of power semiconductor elements are mounted and drives a motor by PWM control is detected, and the modulation rate is determined based on the component. In order to reduce the motor loss, the higher the modulation rate, the higher the carrier frequency of the PWM control, and the detection value of the temperature sensor for detecting the winding temperature of the motor. There is provided a motor control method for correcting the carrier frequency so that the carrier frequency is set higher as the temperature is higher.
Furthermore, in order to achieve the above object, in the present invention, a component of a PWM control modulation factor of an inverter in which a plurality of power semiconductor elements are mounted and drives a motor by PWM control is detected and modulated based on the component. In order to determine the rate and reduce motor loss, the higher the modulation rate, the higher the carrier frequency of the PWM control, and the first line voltage of the motor that is a component of the modulation rate is detected. A motor control method for calculating the modulation factor based on a detection value of a voltage sensor and a second voltage sensor that detects an input voltage of the inverter that is a component of the modulation factor is provided.

Claims (19)

An inverter on which a plurality of power semiconductor elements are mounted and drives a motor by PWM control;
A detection unit for detecting a component of a modulation rate of the PWM control;
A modulation rate determination unit for determining a modulation rate based on the components;
A motor control device comprising: a carrier frequency setting unit configured to set the carrier frequency of the PWM control higher as the modulation rate is higher in order to reduce motor loss. A cooling device that cools the motor with a refrigerant, and a temperature sensor that is attached to the cooling device and detects the temperature of the refrigerant;
The motor control device according to claim 1, wherein the carrier frequency setting unit receives the detection value of the temperature sensor and corrects the carrier frequency so that the carrier frequency is set higher as the temperature of the refrigerant is higher. . The motor control device according to claim 2, wherein the temperature sensor is attached to a cooling channel outlet side of the cooling device. The temperature sensor is composed of first and second temperature sensors attached to the channel outlet side and the channel inlet side of the cooling device, respectively.
The motor control device according to claim 2, wherein the temperature of the refrigerant is a difference between temperatures detected by the first and second temperature sensors. The motor control device according to claim 2, wherein the refrigerant is water. The motor control device according to claim 2, wherein the refrigerant is oil. A temperature sensor for detecting the winding temperature of the motor;
The motor control device according to claim 1, wherein the carrier frequency setting unit receives the detection value of the temperature sensor and corrects the carrier frequency so that the carrier frequency is set higher as the winding temperature is higher. . The motor control device according to claim 7, wherein the temperature sensor is attached to a stator winding of the motor. The motor is a field winding type synchronous motor,
The motor control device according to claim 7, wherein the temperature sensor is attached to a field winding of the motor. The detection unit is a voltage sensor that detects an input voltage of the inverter that is a component of the modulation rate;
The motor control device according to claim 1, wherein the modulation factor determination unit calculates the modulation factor based on the input voltage. A first voltage sensor that detects a line voltage of the motor that is a component of the modulation factor, and a second voltage sensor that detects an input voltage of the inverter that is a component of the modulation factor. And consists of
The motor control device according to claim 1, wherein the modulation factor determination unit calculates the modulation factor based on detection values of the first and second voltage sensors. The modulation factor determination unit is configured to set the carrier frequency to be lower as the input voltage of the inverter detected by the second voltage sensor is higher based on the detection value of the second voltage sensor. The motor control device according to claim 11, wherein the motor is corrected. The detection unit is a rotation speed sensor that detects the rotation speed of the motor that is a component of the modulation rate,
The modulation factor determination unit includes map data in which a modulation factor is set for each rotation speed of the motor, and estimates a modulation ratio according to the rotation speed of the motor with reference to the map data. The motor control apparatus described. The detection unit is a vehicle control device that determines a torque command value of the motor that is a component of the modulation factor,
The modulation factor determining unit has map data in which a modulation factor is set for each torque command value of the motor, and estimates the modulation factor according to the torque command value of the motor with reference to the map data. The motor control device according to 1. The detection unit is a current sensor that detects a phase current of the motor that is a component of the modulation factor,
The motor according to claim 1, wherein the modulation factor determination unit has map data in which a modulation factor is set for each phase current, and estimates the modulation factor according to the phase current with reference to the map data. Control device. The detection unit includes a rotation speed sensor that detects the rotation speed of the motor that is a component of the modulation factor, and a vehicle control device that determines a torque command value of the motor that is a component of the modulation factor. ,
The modulation factor determination unit has map data in which a modulation factor is set for each of the rotation speed and the torque command value, and refers to the map data, and the modulation factor according to the rotation speed and the torque command value of the motor The motor control device according to claim 1. The motor control device according to claim 1, wherein the power semiconductor element is made of a non-Si semiconductor material having a wider band gap than silicon. The motor control device according to claim 17, wherein the non-Si semiconductor material is any one of silicon carbide, a gallium nitride-based material, and diamond. A component of a modulation rate of PWM control of an inverter in which a plurality of power semiconductor elements are mounted and drives a motor by PWM control,
Determining a modulation rate based on the components;
A motor control method for setting the carrier frequency of the PWM control higher as the modulation rate is higher in order to reduce motor loss.

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