JP2006121875A - Motor controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small and inexpensive motor controller in which an inverter and a step up/down converter constituting the motor controller are prevented from being damaged and protected surely even if the number of revolutions of an AC three-phase motor is varied abruptly due to disturbance, or the like. <P>SOLUTION: The motor controller 1 comprises a step up/down converter, an inverter, and a control circuit. The step up/down converter has a reactor. The control circuit comprises an inverter power regulation means 120, an inverter control means, and a step up/down converter control means 121. Start of magnetic saturation of the reactor is detected from variation in current flowing through the reactor, and the inverter power regulation means 120 regulates inverter power. Since generation of eddy current or overvoltage can be suppressed, the inverter and the step up/down converter can be protected without enhancing the current capacity or breakdown voltage of components. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a motor control device that controls a three-phase AC motor.

  Conventionally, as a motor control device, for example, there is an electric motor drive device disclosed in Japanese Patent No. 3308993. This electric motor drive device is composed of a rectifier circuit, a booster circuit, an inverter, and an electric motor control device. An AC power source and an electric motor are connected to the electric motor drive device.

The motor control device calculates the input power from the input current supplied from the AC power source to the rectifier circuit and estimates the DC power. Furthermore, the maximum DC power that can be input to the motor is calculated from the DC current and DC voltage supplied from the booster circuit to the inverter. The motor control device switches the control by determining the operating state of the motor from the magnitude relationship of the DC power with respect to the maximum DC power. For example, when the motor is in a low output state, the motor control device controls the speed of the motor by causing the inverter to control the voltage of the motor. Further, when the motor is in a high output state, the speed of the motor is controlled by controlling the voltage of the motor with a booster circuit.
Japanese Patent No. 3308993

  Here, consider the case where the above-described electric motor driving device is applied to a motor control device for a traveling motor that is mounted on a vehicle such as an electric vehicle and supplies driving force to wheels.

  A travel motor mounted on a vehicle requires a wide drive range, and an inverter that drives the travel motor requires highly responsive control. The control frequency of the inverter is generally several to 20 kHz from the computing ability of the microcomputer of the inverter control device that controls the inverter, the switching speed of the switching elements constituting the inverter, and the like. Further, the booster circuit operates as a step-up / step-down converter so as to cope with power running and regeneration of the traveling motor, and the DC output power required for the step-up / step-down converter also changes according to the output of the traveling motor. The control frequency of the buck-boost converter is generally several to 20 kHz for reasons such as heat generation and withstand voltage of the switching elements constituting the buck-boost converter, in addition to the reason equivalent to that of the inverter control device.

  Therefore, for example, if it is assumed that the rotational speed of the wheel suddenly fluctuates due to a disturbance such as a change in road surface condition while the vehicle is traveling, if the rotational speed increases, the speed of the traveling motor The output also increases rapidly. The inverter rapidly increases the AC power supplied to the traveling motor as the output of the traveling motor increases. The buck-boost converter also increases the DC power supplied to the inverter rapidly. However, since the control frequency of the inverter is close to the control frequency of the buck-boost converter, the DC voltage of the buck-boost converter cannot be increased instantaneously, so only the direct current increases rapidly. Further, when the rotational speed decreases, the output of the traveling motor also decreases rapidly as the rotational speed rapidly decreases. When the output of the traveling motor decreases, a part of the AC power supplied from the inverter to the traveling motor is regenerated, and the DC voltage of the step-up / down converter supplied to the inverter increases rapidly.

  In this way, when the rotational speed of the traveling motor suddenly fluctuates due to disturbances such as changes in road surface conditions, this triggers and overcurrent and overvoltage are generated in the inverter and the buck-boost converter, possibly leading to worst and damage. There is. In order to protect the inverter and the buck-boost converter, a method of increasing the current capacity and the withstand voltage of the components constituting these can be easily considered, but there is a problem that the inverter and the buck-boost converter are increased in size and cost. .

  The present invention has been made in view of such circumstances, and prevents overcurrent and overvoltage of the inverter and the buck-boost converter that constitute the apparatus even if the rotational speed of the three-phase AC motor fluctuates suddenly due to disturbance or the like. Then, it aims at providing the small and low-cost motor control apparatus which can protect reliably with respect to the failure which is the worst event.

  Therefore, the present inventor has intensively studied to solve this problem, and as a result of repeated trial and error, the start of magnetic saturation of the reactor of the buck-boost converter is detected, and the AC power supplied from the inverter to the three-phase AC motor Alternatively, it has been verified that the occurrence of overcurrent and overvoltage can be suppressed by adjusting at least one of the DC voltages supplied from the buck-boost converter to the inverter, and the present invention has been completed.

  That is, the motor control device according to claim 1 includes a reactor and a switching element, controls the current flowing through the reactor by switching the switching element, boosts the DC voltage on the low voltage side, and increases the DC voltage on the high voltage side. A step-up / step-down converter that outputs and outputs the high-voltage side DC voltage to the low-voltage side, and a switching operation of the switching element to control the high-voltage side DC output from the step-up / down converter. A step-up / step-down converter control means for controlling the voltage and the DC voltage on the low-voltage side, DC power output from the high-voltage side of the step-up / down converter is converted into AC power and output to a three-phase AC motor, and An inverter that converts AC power generated by a three-phase AC motor into DC power and outputs the DC power to the high-voltage side of the buck-boost converter; In a motor control device comprising inverter control means for controlling AC power output from an inverter, magnetic saturation detection means for detecting magnetic saturation of the reactor, and in the magnetic saturation period detected by the magnetic saturation detection means, At least one of inverter power adjusting means for adjusting AC power output from the inverter to the three-phase AC motor and step-up / down converter voltage adjusting means for adjusting the DC voltage on the high-voltage side of the buck-boost converter is provided. It is characterized by.

  The motor control device according to claim 2 is the motor control device according to claim 1, wherein the inverter power adjustment means further has a magnitude of change with respect to time of the current flowing through the reactor greater than a predetermined threshold value. It is determined that the magnetic saturation of the reactor has started, and at this time, when the direction of the current flowing through the reactor is from the low voltage side to the high voltage side, the AC power output from the inverter to the three-phase AC motor is When the direction is from the high voltage side to the low voltage side, the AC power output from the inverter to the three-phase AC motor is increased. The step-up / down converter voltage adjusting means determines that the magnetic saturation of the reactor has started when the magnitude of the change of the current flowing through the reactor with respect to time is greater than the predetermined threshold, and at this time, the reactor flows into the reactor. When the current direction is from the low voltage side to the high voltage side direction, the DC voltage on the high voltage side of the buck-boost converter is increased, and when the current direction is from the high voltage side to the low voltage side, the high voltage of the buck-boost converter is increased. The DC voltage on the side is reduced.

  According to a third aspect of the present invention, in the motor control device according to the first or second aspect, the inverter control means further converts the motor torque command input from the outside into a two-phase signal to generate a d-axis current command. And dq-axis current command calculation means for calculating a q-axis current command, dq-axis current calculation means for calculating a d-axis current and a q-axis current by three-phase to two-phase conversion of the phase current of the three-phase AC motor, d-axis voltage command calculation means for calculating a d-axis voltage command and a q-axis voltage command based on the d-axis current command, the q-axis current command, the d-axis current and the q-axis current; and three-phase voltage command calculation means for calculating a three-phase voltage command by performing two-phase three-phase conversion on the q-axis voltage command.

  According to a fourth aspect of the present invention, there is provided the motor control device according to the third aspect, wherein the inverter power adjusting means is the dq-axis current command calculating means in the d-axis current command or the q-axis current. It is characterized by adjusting at least one of the commands.

  According to a fifth aspect of the present invention, there is provided the motor control device according to the third aspect, wherein the inverter power adjustment unit is configured to at least calculate the d-axis current or the q-axis current in the dq-axis current calculation unit. Any one of them is adjusted.

  A motor control device according to a sixth aspect is the motor control device according to the third aspect, wherein the inverter power adjustment means is the dq-axis voltage command or the q-axis voltage in the dq-axis voltage command calculation means. It is characterized by adjusting at least one of the commands.

  According to a seventh aspect of the present invention, there is provided the motor control device according to the third aspect, wherein the inverter power adjustment means adjusts the three-phase voltage command in the three-phase voltage command calculation means. Features.

  The motor control device according to claim 8 is the motor control device according to any one of claims 1 to 7, wherein the inverter is an IGBT (Insulated Gate Bipolar Transistor) or a SiC-MOSFET (SiC-Metal Oxide Semiconductor FET). It has the switching element which becomes.

  According to a ninth aspect of the present invention, in the motor control device according to the first to eighth aspects, the motor control device further controls a three-phase AC motor mounted on the vehicle.

  According to the motor control device of claim 1, at the beginning of the magnetic saturation of the reactor of the buck-boost converter, the AC power output from the inverter to the three-phase AC motor or the DC voltage on the high voltage side of the buck-boost converter By adjusting at least one of them, it is possible to suppress the occurrence of overcurrent and overvoltage in the inverter and the buck-boost converter. Therefore, the inverter and the buck-boost converter can be reliably protected without increasing the current capacity and breakdown voltage of the component.

  By the way, when the number of rotations of the three-phase AC motor suddenly increases due to slipping of the wheels due to disturbance, the output of the three-phase AC motor also increases rapidly. The inverter rapidly increases the AC power supplied to the three-phase AC motor as the output of the three-phase AC motor increases. The buck-boost converter also increases the DC power supplied to the inverter rapidly. However, since the control frequencies of the inverter and the buck-boost converter are close to each other, only the direct current that cannot be increased instantaneously increases rapidly, and the reactor is saturated. At this time, by adjusting the AC power supplied from the inverter to the three-phase AC motor, the increase in the output of the three-phase AC motor can be reduced, and the rapid increase in the DC current can be suppressed. Naturally, a sudden increase in direct current can also be suppressed by adjusting the direct current voltage on the high voltage side of the buck-boost converter.

  On the other hand, when the rotational speed of the three-phase AC motor is suddenly decreased due to the wheel gripping due to disturbance, the output of the three-phase AC motor is also rapidly decreased. When the output of the three-phase AC motor decreases, a part of the electric power supplied from the inverter to the three-phase AC motor is regenerated, and the DC voltage on the high-voltage side of the buck-boost converter supplied to the inverter rises rapidly. When the DC voltage on the high voltage side rises, the buck-boost converter steps down the DC voltage on the high voltage side and outputs it to the low voltage side. Since the DC voltage on the high voltage side is rising rapidly, a large current flows through the reactor and the reactor is saturated. At this time, by adjusting the AC power supplied from the inverter to the three-phase AC motor, the regenerated power can be reduced, and a rapid increase in DC voltage can be suppressed. Naturally, a sudden increase in the DC voltage can also be suppressed by adjusting the DC voltage on the high voltage side of the buck-boost converter.

  Therefore, at the beginning of the magnetic saturation of the reactor of the buck-boost converter, a sudden increase in the direct current or the direct current voltage can be suppressed by adjusting at least one of the power of the inverter or the voltage of the buck-boost converter.

  According to the motor control device of the second aspect, the start of the magnetic saturation of the reactor can be reliably determined by comparing the magnitude of the change of the current flowing through the reactor with respect to time with a predetermined threshold value. Furthermore, based on the direction of the current flowing through the reactor, by increasing or decreasing at least one of the AC power supplied from the inverter to the three-phase AC motor or the DC voltage on the high voltage side of the buck-boost converter, It is possible to reliably suppress a sudden increase in the. Therefore, the inverter and the step-up / down converter can be reliably protected.

  By the way, the current flowing through the reactor changes based on a time constant determined by the resistance and inductance of the reactor. From the direct current superposition characteristics of the reactor, when the reactor is magnetically saturated, the inductance of the reactor is lower than when the reactor is not magnetically saturated. Therefore, as shown in FIG. 8, when the reactor is magnetically saturated, the magnitude of change with respect to time of the current flowing through the reactor is larger than when the reactor is not magnetically saturated. Therefore, the presence or absence of magnetic saturation of the reactor can be reliably determined by comparing the magnitude of the change of the current flowing through the reactor with respect to time with a predetermined threshold.

  As described above, when the rotation speed of the three-phase AC motor rapidly increases due to slipping of the wheels due to disturbance, the step-up / step-down converter rapidly increases the DC power supplied to the inverter. However, since the DC voltage of the buck-boost converter cannot be increased instantaneously, the DC current flowing from the low voltage side toward the high voltage side to which the inverter is connected increases rapidly and the reactor is saturated. At this time, by reducing the AC power supplied from the inverter to the three-phase AC motor, it is possible to reduce the increase in the output of the three-phase AC motor and suppress the rapid increase in DC current. Naturally, a sudden increase in DC current can also be suppressed by increasing the switching frequency of the switching element of the buck-boost converter and increasing the DC voltage on the high voltage side.

  On the other hand, when the rotational speed of the three-phase AC motor is suddenly lowered due to the gripping of the wheels due to disturbance, the DC voltage on the high-voltage side of the buck-boost converter rises rapidly. When the DC voltage on the high voltage side increases, the buck-boost converter steps down the DC voltage on the high voltage side and outputs it to the low voltage side. Since the DC voltage on the high voltage side is rising rapidly, a large current flows through the reactor from the high voltage side to the low voltage side, and the reactor is saturated. At this time, by increasing the AC power supplied from the inverter to the three-phase AC motor, the regenerated power can be reduced, and a rapid increase in DC voltage can be suppressed. Naturally, a sudden increase in the DC voltage can also be suppressed by increasing the switching frequency of the switching elements constituting the buck-boost converter and decreasing the DC voltage on the high voltage side.

  Therefore, based on the direction of the current flowing through the reactor, by increasing or decreasing at least one of the AC power supplied from the inverter to the three-phase AC motor or the DC voltage on the high voltage side of the buck-boost converter, It is possible to reliably suppress a sudden increase in the.

  According to the motor control device of the third aspect, since the response of the control of the inverter that drives the traveling motor can be sufficiently increased, the step-up / down converter does not delay the timing at which the start of the magnetic saturation of the reactor is detected. The supplied DC power can be reliably converted to AC power and supplied to the three-phase AC motor.

  According to the motor control device of the fourth aspect, the dq-axis current command calculation means adjusts at least one of the d-axis current command and the q-axis current command, thereby supplying the AC to the three-phase AC motor from the inverter. Power can be increased or decreased reliably.

  According to the motor control device of the fifth aspect, the dq-axis current calculation means ensures the AC power supplied from the inverter to the three-phase AC motor by adjusting at least one of the d-axis current and the q-axis current. Can be increased or decreased.

  According to the motor control device of the sixth aspect, the dq-axis voltage command calculation means adjusts at least one of the d-axis voltage command and the q-axis voltage command, thereby supplying the AC to the three-phase AC motor from the inverter. Power can be increased or decreased reliably.

  According to the motor control device of the seventh aspect, by adjusting the three-phase voltage command in the three-phase voltage command calculation means, the AC power supplied from the inverter to the three-phase AC motor can be reliably increased or decreased. .

  According to the motor control device of the eighth aspect, the switching signal frequency of the switching element constituting the inverter is made higher than the switching signal frequency of the switching element constituting the buck-boost converter without lowering the control response of the inverter. Thus, the high-voltage side DC voltage of the boost converter can be reliably adjusted.

  According to the motor control device of the ninth aspect, overcurrent and overvoltage of the inverter and the buck-boost converter of the motor control device mounted on the vehicle can be prevented and reliably protected. Therefore, the reliability of the vehicle can be improved, and the increase in size and cost can be suppressed.

  The present embodiment shows an example in which the motor control device according to the present invention is applied to a motor control device that controls a traveling three-phase AC motor mounted on a vehicle.

(First embodiment)
FIG. 1 is a circuit diagram of the motor control device according to the first embodiment, and FIG. 2 is a block diagram of the control circuit. Then, with reference to FIG. 1 and FIG. 2, a specific description will be given in the order of configuration, operation, and effect.

  First, a specific configuration will be described. As shown in FIG. 1, the motor control device 1 includes a step-up / down converter 10, an inverter 11, and a control circuit 12. The motor control device 1 is connected to a DC power source 2 made of a secondary battery and a three-phase AC motor 3 having a rotational position detection sensor 3a. Further, current sensors 4 a and 4 b for detecting the V-phase and W-phase currents of the three-phase AC motor 3 are arranged between the motor control device 1 and the three-phase AC motor 3, respectively. The rotational position detection sensor 3a can be omitted by calculating the rotational angle θ from the motor voltage, current, and the like.

  The step-up / down converter 10 is a circuit that is controlled by the control circuit 12 and boosts the DC voltage output from the DC power supply 2 on the low voltage side to supply DC power to the inverter 11 on the high voltage side. Conversely, it is also a circuit that steps down the DC voltage based on the DC power generated by the three-phase AC motor 3 output from the high-voltage side inverter 11 and charges the low-voltage side DC power source 2. The buck-boost converter 10 includes a low-voltage side smoothing capacitor 10a, a reactor 10b, a reactor current detection resistor 10c, a buck-boost IGBT 10d, 10e (switching element), a flywheel diode 10f, 10g, and a high-voltage side smoothing capacitor. 10h.

  The low-voltage side smoothing capacitor 10a is an element for smoothing the low-voltage side DC voltage. The low-voltage side smoothing capacitor 10a smoothes the DC voltage output from the DC power source 2 during the boosting operation, and smoothes the stepped-down DC voltage that charges the DC power source 2 during the step-down operation. One end of the low-voltage side smoothing capacitor 10 a is connected to the positive terminal of the DC power supply 2, and the other end is connected to the negative terminal of the DC power supply 2.

  The reactor 10b is an element that accumulates and releases magnetic energy and induces a voltage when a current flows. One end of the reactor 10b is connected to one end of the low-voltage side smoothing capacitor 10a, and the other end is connected to one end of the reactor current detection resistor 10c.

  Reactor current detection resistor 10c is an element for detecting a reactor current flowing through reactor 10b. One end of the reactor current detection resistor 10c is connected to the other end of the reactor 10b, and the other end of the reactor current detection resistor 10c is connected to a step-up / step-down IGBT 10d, 10e described later. Further, both ends of the reactor current detection resistor 10c are connected to the control circuit 12, respectively.

  The step-up / down IGBTs 10d and 10e are switching elements for storing and releasing magnetic energy in the reactor 10b by turning on and off. The collector of the step-up / down IGBT 10d is connected to the inverter, the emitter is connected to the collector of the step-up / down IGBT 10e, and the emitter of the step-up / down IGBT 10e is connected to the other end of the low-voltage side smoothing capacitor 10a and the inverter 11. The gates of the step-up / down IGBTs 10d and 10e are connected to the control circuit 12, respectively. The connection point between the step-up / down IGBT 10d and the step-up / down IGBT 10e is connected to the other end of the reactor current detection resistor 10c.

  The flywheel diodes 10f and 10g are elements for flowing a flywheel current generated when the buck-boost IGBT 10d or the buck-boost IGBT 10e is turned off and energy stored in the reactor 10b is released. The anodes of the flywheel diodes 10f, 10g are connected to the emitters of the buck-boost IGBTs 10d, 10e, and the cathodes are connected to the collectors of the buck-boost IGBTs 10d, 10e, respectively.

  The high-voltage side smoothing capacitor 10h is an element for smoothing the high-voltage side DC voltage. The high-voltage side smoothing capacitor 10h smoothes the boosted DC voltage supplied to the inverter 11 during the step-up operation, and smoothes the DC voltage output from the inverter 11 during the step-down operation. One end of the high-voltage side smoothing capacitor 10h is connected to the collector of the buck-boost IGBT 10d, and the other end is connected to the emitter of the buck-boost IGBT 10e.

  The inverter 11 is controlled by the control circuit 12 and, when the three-phase AC motor 3 is in the power running state, converts the DC power based on the boosted DC voltage supplied by the step-up / down converter 10 into AC power, and thereby the three-phase AC motor 3 is a circuit to be supplied. Conversely, when the three-phase AC motor 3 is in a regenerative state, the AC power generated by the three-phase AC motor 3 is also converted into DC power and output to the step-up / down converter 10. The inverter 11 includes inverter IGBTs 11a to 11f and flywheel diodes 11g to 11l.

  The inverter IGBTs 11a to 11f are switching elements for converting DC power into AC power by turning on and off. The inverter IGBTs 11a to 11f are connected in a three-phase bridge. The collectors of the three inverter IGBTs 11a to 11c on the upper side of the inverter 11 are connected to one end of the high-voltage side smoothing capacitor 10h, and the emitters of the three IGBTs 11d to 11f on the lower side are connected to the other end of the high-voltage side smoothing capacitor 10h. Has been. The connection points of the inverter IGBTs 11a and 11d, the inverter IGBTs 11b and 11e, and the inverter IGBTs 11c and 11f are connected to the three-phase AC motor 3, respectively.

  The flywheel diodes 11g to 11l are elements for converting AC power into DC power by rectification. The anodes of the flywheel diodes 11g to 11l are connected to the emitters of the inverter IGBTs 11a to 11f, and the cathodes are connected to the collectors of the inverter IGBTs 11a to 11f, respectively.

  The control circuit 12 is based on the motor torque command Trq * output from the vehicle ECU (not shown), the reactor current of the step-up / down converter 10, the low-voltage and high-voltage DC voltages, the rotational position of the three-phase AC motor 3, and the phase current. And a circuit for controlling the buck-boost converter 10 and the inverter 11. As shown in FIG. 2, the control circuit 12 includes an inverter power adjusting unit 120, an inverter control unit 121, and a buck-boost converter control unit 122.

  The inverter power adjustment means 120 determines the presence or absence of magnetic saturation of the reactor 10b from the reactor current of the buck-boost converter 10, and outputs an adjustment command for adjusting the inverter power to the inverter control means 121 when magnetic saturation occurs. . Inverter power adjustment means 120 includes reactor current detection means 120a, reactor magnetic saturation determination means 120b (magnetic saturation detection means), and dq-axis current command adjustment means 120c.

  Reactor current detection means 120a is connected to both ends of reactor current detection resistor 10c, and calculates reactor current IL flowing through reactor 10b based on the voltage at both ends of reactor current detection resistor 10c.

  Reactor magnetic saturation determination means 120b calculates a change of reactor current IL with respect to time. And when the magnitude | size of the change with respect to the time of the reactor electric current IL is larger than the preset threshold value, it determines with the reactor 10b being magnetically saturated. Furthermore, the reactor magnetic saturation determination means 120b determines the direction of the current flowing through the reactor 10b from the polarity of the reactor current IL calculated by the reactor current detection means 120a.

  The dq-axis current command adjustment unit 120c calculates an adjustment command based on the determination result of the reactor magnetic saturation determination unit 120b. The dq-axis current command adjusting means 120c calculates an adjustment command for reducing the q-axis current command Iq * when the current flows from the low voltage side to the high voltage side and the reactor 10b is magnetically saturated. When the current flows from the high voltage side toward the low voltage side and the reactor 10b is magnetically saturated, an adjustment command for increasing the q-axis current command Iq * is calculated.

  The inverter control means 121 includes a motor torque command Trq * output from the vehicle ECU, an adjustment command output from the inverter power adjustment means 120, a boosted DC voltage supplied from the step-up / down converter 10 to the inverter 11, and the three-phase AC motor 3. The inverter 11 is controlled based on the phase current and the rotational position. The inverter control unit 121 includes an inverter input voltage detection unit 121a, a motor rotation position detection unit 121b, a motor rotation number calculation unit 121c, a dq axis current command calculation unit 121d, a motor current detection unit 121e, and a dq axis current calculation. Means 121f, dq-axis voltage command calculation means 121g, three-phase voltage command calculation means 121h, inverter PWM (Pulse Width Modulation) signal generation means 121i, and inverter gate driver 121j.

  The inverter input voltage detection means 121 a is connected to the high voltage side of the buck-boost converter 10 and calculates the inverter input voltage Vinv based on the boosted DC voltage supplied from the buck-boost converter 10.

  The motor rotation position detection means 121b is connected to the rotation position detection sensor 3a, and calculates the rotation angle θ of the three-phase AC motor 3 based on the rotation position signal of the three-phase AC motor 3 output from the rotation position detection sensor 3a. .

  The motor rotation number calculation unit 121c calculates the motor rotation number Nmot of the three-phase AC motor 3 based on the rotation angle θ of the three-phase AC motor 3 calculated by the motor rotation position detection unit 121b.

  The dq-axis current command calculation means 121d is a motor torque command Trq output from the vehicle ECU based on the inverter input voltage Vinv calculated by the inverter input voltage detection means 121a and the motor rotation speed Nmot calculated by the motor rotation speed calculation means 121c. * Is converted to a value suitable for arithmetic processing, and two-phase conversion is performed to calculate d-axis and q-axis current commands Id * and Iq *. When reactor 10b is magnetically saturated, q-axis current command Iq * is adjusted based on the adjustment command calculated by dq-axis current command adjustment means 120c.

  The motor current detection means 121e is connected to the current sensors 4a and 4b, and based on the V-phase and W-phase current signals of the three-phase AC motor 3 output from the current sensors 4a and 4b, the V-phase of the three-phase AC motor 3 And W-phase currents Iv and Iw are calculated.

  The dq-axis current calculation means 121f calculates the U-phase current from the V-phase and W-phase currents Iv and Iw of the three-phase AC motor 3 calculated by the motor current detection means 121e, and further calculates the three-phase calculated by the motor rotational position detection means 121b. Two-phase three-phase conversion is performed based on the rotation angle θ of the phase AC motor 3 to calculate the d-axis and q-axis currents Id and Iq.

  The dq-axis voltage command calculation means 121g is configured to calculate the d-axis and q-axis current commands Id * and Iq * calculated by the dq-axis current command calculation means 121d and the d-axis and q-axis currents Id and Iq calculated by the dq-axis current calculation means 121f. And calculating at least one of a deviation between the d-axis current command Id * and the d-axis current Id and a deviation between the q-axis current command Iq * and the q-axis current Iq, and the d-axis and q-axis voltage commands Vd *, Vq * Is calculated.

  The three-phase voltage command calculation means 121h uses the d-axis and q-axis voltage commands Vd * and Vq * calculated by the dq-axis voltage command calculation means 121g as the rotation angle θ of the three-phase AC motor 3 calculated by the motor rotation position detection means 121b. Based on the two-phase three-phase conversion, three-phase voltage commands Vu *, Vv *, Vw * are calculated.

  The inverter PWM signal generating means 121i is configured to turn on and off the inverter IGBTs 11a to 11f based on the three-phase voltage commands Vu *, Vv *, and Vw * calculated by the three-phase voltage command calculating means 121h. , VV, VW are output.

  Based on the inverter PWM signals VU, VV, and VW output from the inverter PWM signal generator 121i, the inverter gate driver 121j applies the gate voltages UU, UL, VU, VL, WU, and WL to the inverter IGBTs 11a to 11f. Output.

  The step-up / down converter control means 122 includes the d-axis and q-axis current commands Id * and Iq * calculated by the inverter control means 121, the d-axis and q-axis voltage commands Vd * and Vq *, the DC voltage of the DC power supply 2 and the inverter input. The buck-boost converter 10 is controlled based on the inverter input voltage Vinv calculated by the voltage detection means 121a. The step-up / step-down converter control means 122 includes a motor output calculation means 122a, a DC power supply voltage detection means 122b, an output voltage command calculation means 122c, a converter PWM signal generation means 122d, and a converter gate driver 122e. Yes.

  The motor output calculation means 122a includes the d-axis and q-axis current command Id * calculated by the dq-axis current command calculation means 121d, the d-axis and q-axis voltage command Vd * calculated by the Iq * and dq-axis voltage command calculation means 121g, Based on Vq *, the motor output Pmot of the three-phase AC motor 3 is calculated.

  The DC power supply voltage detection unit 122b is connected to the positive terminal and the negative terminal of the DC power supply 2, and calculates the DC power supply voltage Vbat based on the voltage between the positive terminal and the negative terminal of the DC power supply 2.

  The output voltage command calculation means 122c is used to set the motor output Pmot calculated by the motor output calculation means 122a, the DC power supply voltage Vbat calculated by the DC power supply voltage detection means 122b, and the inverter input voltage Vinv calculated by the inverter input voltage detection means 121a. Based on this, an output voltage command Vdc * of the buck-boost converter 10 is calculated.

  The converter PWM signal generating means 122d outputs a converter PWM signal VD for turning on / off the step-up / down IGBTs 10d and 10e based on the output voltage command Vdc * calculated by the output voltage command calculating means 122c.

  The converter gate driver 122e outputs the gate voltages DU and DL of the step-up / down IGBTs 10d and 10e based on the converter PWM signal VD output from the converter PWM signal generator 122d.

  Next, a specific operation will be described with reference to FIG. First, the operation of the buck-boost converter 10 will be described. As shown in FIG. 2, the motor output calculation means 122 a is a motor for the three-phase AC motor 3 based on the d-axis and q-axis current commands Id * and Iq * and the d-axis and q-axis voltage commands Vd * and Vq *. The output Pmot is calculated. The DC power supply voltage detection means 122b calculates the DC power supply voltage Vbat based on the voltage between the terminals of the DC power supply 2.

  Based on the motor output Pmot, the DC power supply voltage Vbat corresponding to the DC voltage on the low-voltage side of the buck-boost converter 10, and the inverter input voltage Vinv corresponding to the DC voltage on the high-voltage side of the buck-boost converter 10, the output voltage command calculation means 122c An output voltage command Vdc * of the pressure converter 10 is calculated. The converter PWM signal generating means 122d outputs a converter PWM signal VD for turning on / off the step-up / down IGBTs 10d, 10e based on the output voltage command Vdc *. The converter gate driver 122e outputs the gate voltages DU and DL of the step-up / down IGBTs 10d and 10e based on the converter PWM signal VD.

  The step-up / step-down IGBTs 10 d and 10 e are switched by applying the gate voltages DU and DL to boost the DC voltage output from the low-voltage DC power supply 2 and supply the boosted voltage to the high-voltage inverter 11. Conversely, the DC voltage based on the DC power output from the inverter 11 on the high voltage side is stepped down to charge the DC power source 2 on the low voltage side.

  Next, the operation of the inverter 11 will be described. The inverter input voltage detection unit 121a calculates the inverter input voltage Vinv based on the boosted DC voltage supplied from the step-up / down converter 10. The motor rotation position detection means 121b calculates the rotation angle θ of the three-phase AC motor 3 based on the rotation position signal of the three-phase AC motor 3 output from the rotation position detection sensor 3a. The motor rotation speed calculation means 121 c calculates the motor rotation speed Nmot of the three-phase AC motor 3 based on the rotation angle θ of the three-phase AC motor 3.

  When the motor torque command Trq * is input from the vehicle ECU, the dq-axis current command calculation means 121d converts the motor torque command Trq * into a value suitable for calculation processing based on the inverter input voltage Vinv and the motor rotation speed Nmot. Further, two-phase conversion is performed to calculate the d-axis and q-axis current commands Id * and Iq *.

  The motor current detection means 121e calculates the V-phase and W-phase currents Iv and Iw of the three-phase AC motor 3 based on the V-phase and W-phase current signals of the three-phase AC motor 3 output from the current sensors 4a and 4b. To do. The dq-axis current calculation means 121f calculates the U-phase current from the V-phase and W-phase currents Iv and Iw of the three-phase AC motor 3, and further performs two-phase and three-phase conversion based on the rotation angle θ of the three-phase AC motor 3. D-axis and q-axis currents Id and Iq are calculated.

  The dq-axis voltage command calculation means 121g is configured to calculate a deviation between the d-axis current command Id * and the d-axis current Id and q based on the d-axis and q-axis current commands Id * and Iq * and the d-axis and q-axis currents Id and Iq. At least one of the deviations between the shaft current command Iq * and the q-axis current Iq is calculated, and the d-axis and q-axis voltage commands Vd * and Vq * are calculated. The three-phase voltage command calculation means 121h converts the d-axis and q-axis voltage commands Vd * and Vq * into two-phase and three-phase based on the rotation angle θ of the three-phase AC motor 3, and converts the three-phase voltage commands Vu * and Vv *. , Vw * is calculated. The inverter PWM signal generating means 121i outputs inverter PWM signals VU, VV, and VW for turning on and off the inverter IGBTs 11a to 11f based on the three-phase voltage commands Vu *, Vv *, and Vw *. The inverter gate driver 121j outputs gate voltages UU, UL, VU, VL, WU, and WL to the inverter IGBTs 11a to 11f based on the inverter PWM signals VU, VV, and VW.

  The inverter IGBTs 11a to 11f are switched by applying gate voltages UU, UL, VU, VL, WU, and WL, and convert DC power supplied from the high voltage side of the buck-boost converter 10 into AC power. The phase AC motor 3 is supplied. The three-phase AC motor 3 is supplied with AC power from the inverter 11 and generates torque instructed by the motor torque command Trq *. Further, when the three-phase AC motor 3 is in a regenerative state, AC power generated by the three-phase AC motor 3 is rectified by the flywheel diodes 11 g to 11 l, converted into DC power, and supplied to the step-up / down converter 10. Torque generated by the three-phase AC motor 3 is transmitted to the wheels via the transmission mechanism, and the vehicle starts running.

  By the way, when the rotation speed of the three-phase AC motor 3 rapidly increases due to a disturbance such as a change in road surface condition, the output of the three-phase AC motor 3 also increases rapidly. The inverter 11 rapidly increases the AC power supplied to the three-phase AC motor 3 as the output of the three-phase AC motor 3 increases. The step-up / down converter 10 also rapidly increases the DC power supplied to the inverter 11. However, since the AC power supplied to the three-phase AC motor 3 is larger than the DC power supplied to the inverter 11, the DC current increases rapidly. As shown in FIG. 1, this direct current flows through the direct current power source 2, the reactor 10b, the reactor current detection resistor 10c, and the flywheel diode 10f through the path to the inverter 11, and the magnetic saturation of the reactor 10b starts.

  At this time, the reactor current detection means 120a calculates the reactor current IL flowing through the reactor 10b based on the voltage across the reactor current detection resistor 10c. Reactor magnetic saturation determination means 120b calculates a change of reactor current IL with respect to time and compares it with a preset threshold value. Reactor 10b is magnetically saturated, and the magnitude of change with respect to time of the current flowing through reactor 10b is larger than when magnetic saturation is not achieved. Therefore, by setting the threshold value appropriately, the reactor magnetic saturation determination unit 120b can determine that the reactor 10b is magnetically saturated. Furthermore, the reactor magnetic saturation determination means 120b determines that current flows from the low voltage side to the high voltage side in the reactor 10b from the polarity of the reactor current IL. The dq-axis current command adjusting means 120c calculates an adjustment command for reducing the q-axis current command Iq * when the current flows from the low voltage side to the high voltage side and the reactor 10b is magnetically saturated.

  When the reactor 10b is magnetically saturated, the dq-axis current command calculation unit 121d decreases the q-axis current command Iq * based on the adjustment command calculated by the dq-axis current command adjustment unit 120c. As q-axis current command Iq * decreases, q-axis voltage command Vq * decreases and three-phase voltage commands Vu *, Vv *, and Vw * decrease. Finally, the AC power supplied from the inverter 11 to the three-phase AC motor 3 decreases. Thereby, the increase in the output accompanying the rapid increase in the rotation speed of the three-phase AC motor 3 is reduced, and the rapid increase in the direct current is suppressed.

  More specifically, according to the DC superposition characteristics of the reactor 10b, once the reactor 10b is magnetically saturated, the inductance of the reactor 10b decreases, and the energy accumulated in the reactor 10b decreases, so the current flowing through the reactor 10b increases. In addition, a vicious cycle in which the inductance of the reactor 10b is reduced continues to fall into an uncontrollable state, and the current flowing through the reactor 10b continues to increase. The threshold value preset in the reactor magnetic saturation determination means 120b is a boundary value as to whether or not the reactor 10b is magnetically saturated, and reduces the AC power supplied from the inverter 11 to the three-phase AC motor 3 as described above. By doing so, the magnetic saturation of the reactor 10b can be prevented, so that a rapid increase in direct current can be suppressed.

  On the other hand, when the rotation speed of the three-phase AC motor 3 rapidly decreases due to disturbance such as a change in road surface condition, the output of the three-phase AC motor 3 also decreases rapidly. When the output of the three-phase AC motor 3 decreases, a part of the power supplied from the inverter 11 to the three-phase AC motor 3 is regenerated, and the DC voltage on the high voltage side of the step-up / down converter 10 supplied to the inverter 11 is increased. It rises rapidly. When the DC voltage on the high voltage side rises, the buck-boost converter 10 steps down the DC voltage on the high voltage side and outputs it to the low voltage side. Since the DC voltage on the high voltage side has increased rapidly, as shown in FIG. 1, during the step-down operation, the DC power supply passes through the high voltage side smoothing capacitor 10h, the step-up / step-down IGBT 10d, the reactor current detection resistor 10c, and the reactor 10b. A large current flows in the path leading to 2, and the magnetic saturation of the reactor 10b begins.

  At this time, the reactor current detection means 120a calculates the reactor current IL flowing through the reactor 10b based on the voltage across the reactor current detection resistor 10c. Reactor magnetic saturation determination means 120b calculates a change of reactor current IL with respect to time and compares it with a preset threshold value. Reactor 10b is magnetically saturated, and the magnitude of change with respect to time of the current flowing through reactor 10b is larger than when magnetic saturation is not achieved. Therefore, by setting the threshold value appropriately, the reactor magnetic saturation determination unit 120b can determine that the reactor 10b is magnetically saturated. Furthermore, the reactor magnetic saturation determining means 120b determines that the current flows through the reactor 10b from the high voltage side to the low voltage side based on the polarity of the reactor current IL. The dq-axis current command adjusting means 120c calculates an adjustment command for increasing the q-axis current command Iq * when the current flows from the high voltage side to the low voltage side and the reactor 10b is magnetically saturated.

  When the reactor 10b is magnetically saturated, the dq-axis current command calculating unit 121d increases the q-axis current command Iq * based on the adjustment command calculated by the dq-axis current command adjusting unit 120c. As the q-axis current command Iq * increases, the q-axis voltage command Vq * increases and the three-phase voltage commands Vu *, Vv *, and Vw * increase. Finally, the AC power supplied from the inverter 11 to the three-phase AC motor 3 increases. Thereby, the electric power regenerated from the three-phase AC motor 3 via the inverter 11 is reduced, and a rapid increase in DC voltage can be suppressed.

  Finally, specific effects will be described. According to the first embodiment, it is possible to reliably determine the start of magnetic saturation of the reactor 10b by comparing the magnitude of the change of the current flowing through the reactor 10b with respect to time with a predetermined threshold. Furthermore, the generation of overcurrent and overvoltage can be suppressed by increasing or decreasing the AC power supplied from the inverter 11 to the three-phase AC motor 3 based on the direction of the current flowing through the reactor 10b. Therefore, the inverter 11 and the buck-boost converter 10 can be reliably protected without increasing the current capacity and breakdown voltage of the components.

  Further, the inverter control means 121 includes the dq-axis current command calculation means 121d, the dq-axis current calculation means 121f, the dq-axis voltage command calculation means 121g, and the three-phase voltage command calculation means 121h, thereby starting the magnetic saturation of the reactor 10b. The DC power supplied from the step-up / step-down converter 10 can be reliably converted to AC power and supplied to the three-phase AC motor 3 without delay at the timing when the signal is detected.

  Further, the AC power supplied from the inverter 11 to the three-phase AC motor 3 can be reliably increased or decreased by increasing or decreasing the q-axis current command Iq * by the dq-axis current command adjusting means 120c. Further, by configuring the inverter 11 with an IGBT, the switching signal frequency of the inverter 11 can be made higher than the switching signal frequency of the buck-boost converter 10 without lowering the control response of the inverter 11. The high-voltage side DC voltage can be adjusted reliably. Furthermore, overcurrent and overvoltage of the inverter 11 and the step-up / down converter 10 of the motor control device 1 mounted on the vehicle can be prevented and reliably protected. Therefore, the reliability of the vehicle can be improved, and the increase in size and cost can be suppressed.

  In the above-described embodiment, an example in which only the q-axis current command Iq * is adjusted is described, but the present invention is not limited to this. It is only necessary to adjust at least one of the d-axis current command Id * and the q-axis current command Iq *. Even in this case, the AC power output from the inverter 11 to the three-phase AC motor 3 can be increased or decreased.

(Second Embodiment)
Next, FIG. 3 shows a block diagram of a control circuit in the second embodiment. Here, only the inverter power adjustment means and the inverter control means, which are different from the motor control device according to the first embodiment, will be described, and the description of the common parts other than the necessary parts will be omitted. In addition, the same code | symbol is attached | subjected and demonstrated to the element same as the said embodiment.

  First, a specific structure will be described. As shown in FIG. 3, the inverter power adjustment means 120 includes a reactor current detection means 120a, a reactor magnetic saturation determination means 120b, and a dq axis current adjustment means 120d.

  The dq-axis current adjustment unit 120d calculates an adjustment command based on the determination result of the reactor magnetic saturation determination unit 120b. The dq-axis current adjusting unit 120d calculates an adjustment command for increasing the q-axis current Iq when the current flows from the low voltage side to the high voltage side and the reactor 10b is magnetically saturated. When the current flows from the high voltage side toward the low voltage side and the reactor 10b is magnetically saturated, an adjustment command for reducing the q-axis current Iq is calculated.

  The inverter control unit 121 includes an inverter input voltage detection unit 121a, a motor rotation position detection unit 121b, a motor rotation number calculation unit 121c, a dq axis current command calculation unit 121d, a motor current detection unit 121e, and a dq axis current calculation. It comprises means 121f, dq-axis voltage command calculation means 121g, three-phase voltage command calculation means 121h, inverter PWM signal generation means 121i, and inverter gate driver 121j.

  Based on the inverter input voltage Vinv calculated by the inverter input voltage detection unit 121a and the motor rotation number Nmot calculated by the motor rotation number calculation unit 121c, the dq axis current command calculation unit 121d outputs a motor torque command Trq * output from the vehicle ECU. Is converted into a value suitable for arithmetic processing, and further two-phase converted to calculate the d-axis and q-axis current commands Id * and Iq *.

  The dq-axis current calculation means 121f calculates the U-phase current from the V-phase and W-phase currents Iv and Iw of the three-phase AC motor 3 calculated by the motor current detection means 121e, and calculates the three-phase calculated by the motor rotational position detection means 121b. Two-phase three-phase conversion is performed based on the rotation angle θ of the AC motor 3 to calculate the d-axis and q-axis currents Id and Iq. Further, when reactor 10b is magnetically saturated, q-axis current Iq is adjusted based on the adjustment command calculated by dq-axis current adjustment means 120d.

  Next, a specific operation will be described. When the rotational speed of the three-phase AC motor 3 suddenly increases due to a disturbance such as a change in the road surface condition, the output of the three-phase AC motor 3 increases rapidly, a current flows through the reactor 10b from the low pressure side to the high pressure side, and the reactor 10b. Is magnetically saturated.

  The dq-axis current adjusting unit 120d calculates an adjustment command for increasing the q-axis current Iq when the current flows from the low voltage side to the high voltage side and the reactor 10b is magnetically saturated. When the reactor 10b is magnetically saturated, the dq axis current calculation unit 121f increases the q axis current Iq based on the adjustment command calculated by the dq axis current adjustment unit 120d. By increasing the q-axis current Iq, the deviation between the q-axis current command Iq * and the q-axis current Iq becomes a negative value, the PI calculation value is decreased, the q-axis voltage command Vq * is decreased, and the three-phase voltage The commands Vu *, Vv *, Vw * are decreased. Finally, the AC power supplied from the inverter 11 to the three-phase AC motor 3 decreases. As a result, an increase in output due to a rapid increase in the rotational speed of the three-phase AC motor 3 is reduced, and a rapid increase in DC current is suppressed.

  On the other hand, when the rotation speed of the three-phase AC motor 3 rapidly decreases due to disturbance such as a change in road surface condition, a current flows through the reactor 10b from the high pressure side to the low pressure side, and the reactor 10b is magnetically saturated.

  The dq-axis current adjusting unit 120d calculates an adjustment command for decreasing the q-axis current Iq when the current flows from the high voltage side to the low voltage side and the reactor 10b is magnetically saturated. When the reactor 10b is magnetically saturated, the dq-axis current calculation unit 121f decreases the q-axis current Iq based on the adjustment command calculated by the dq-axis current adjustment unit 120d. As q-axis current Iq decreases, the deviation between q-axis current command Iq * and q-axis current Iq becomes a positive value, PI calculation value increases, q-axis voltage command Vq * increases, and three-phase voltage The commands Vu *, Vv *, Vw * are increased. Finally, the AC power supplied from the inverter 11 to the three-phase AC motor 3 increases. Thereby, the electric power regenerated from the three-phase AC motor 3 via the inverter 11 is reduced, and a rapid increase in DC voltage can be suppressed.

  Finally, specific effects will be described. According to the second embodiment, the AC power supplied from the inverter 11 to the three-phase AC motor 3 can be reliably increased or decreased by increasing or decreasing the q-axis current Iq by the dq-axis current calculation adjusting means 120d.

  In the above-described embodiment, an example in which only the q-axis current Iq is adjusted is described, but the present invention is not limited to this. It is sufficient if at least one of the d-axis current Id and the q-axis current Iq can be adjusted. Even in this case, the AC power output from the inverter 11 to the three-phase AC motor 3 can be increased or decreased.

(Third embodiment)
Next, FIG. 4 shows a block diagram of a control circuit in the third embodiment. Here, only the inverter power adjustment means and the inverter control means, which are different from the motor control device according to the first embodiment, will be described, and the description of the common parts other than the necessary parts will be omitted. In addition, the same code | symbol is attached | subjected and demonstrated to the element same as the said embodiment.

  First, a specific structure will be described. As shown in FIG. 4, the inverter power adjustment means 120 includes a reactor current detection means 120a, a reactor magnetic saturation determination means 120b, and a dq axis voltage command adjustment means 120e.

  The dq axis voltage command adjusting unit 120e calculates an adjustment command based on the determination result of the reactor magnetic saturation determination unit 120b. The dq axis voltage command adjusting means 120e calculates an adjustment command for decreasing the q axis voltage command Vq * when a current flows from the low voltage side to the high voltage side and the reactor 10b is magnetically saturated. When the current flows from the high voltage side toward the low voltage side and the reactor 10b is magnetically saturated, an adjustment command for increasing the q-axis voltage command Vq * is calculated.

  The inverter control unit 121 includes an inverter input voltage detection unit 121a, a motor rotation position detection unit 121b, a motor rotation number calculation unit 121c, a dq axis current command calculation unit 121d, a motor current detection unit 121e, and a dq axis current calculation. It comprises means 121f, dq-axis voltage command calculation means 121g, three-phase voltage command calculation means 121h, inverter PWM signal generation means 121i, and inverter gate driver 121j.

  Based on the inverter input voltage Vinv calculated by the inverter input voltage detection unit 121a and the motor rotation number Nmot calculated by the motor rotation number calculation unit 121c, the dq axis current command calculation unit 121d outputs a motor torque command Trq * output from the vehicle ECU. Is converted into a value suitable for arithmetic processing, and further two-phase converted to calculate the d-axis and q-axis current commands Id * and Iq *.

  The dq-axis voltage command calculation means 121g is configured to calculate the d-axis and q-axis current commands Id * and Iq * calculated by the dq-axis current command calculation means 121d and the d-axis and q-axis currents Id and Iq calculated by the dq-axis current calculation means 121f. Based on the above, d-axis and q-axis voltage commands Vd * and Vq * are calculated. Further, when reactor 10b is magnetically saturated, q-axis voltage command Vq * is adjusted based on the adjustment command calculated by dq-axis voltage command adjustment means 120e.

  Next, a specific operation will be described. When the rotational speed of the three-phase AC motor 3 increases rapidly due to a disturbance such as a change in road surface condition, a current flows through the reactor 10b from the low pressure side to the high pressure side, and the reactor 10b is magnetically saturated.

  The dq axis voltage command adjusting means 120e calculates an adjustment command for decreasing the q axis voltage command Vq * when a current flows from the low voltage side to the high voltage side and the reactor 10b is magnetically saturated. When the reactor 10b is magnetically saturated, the dq axis voltage command calculating unit 121g decreases the q axis voltage command Vq * based on the adjustment command calculated by the dq axis voltage command adjusting unit 120e. As the q-axis voltage command Vq * decreases, the three-phase voltage commands Vu *, Vv *, and Vw * decrease. Finally, the AC power supplied from the inverter 11 to the three-phase AC motor 3 decreases. As a result, an increase in output due to a rapid increase in the rotational speed of the three-phase AC motor 3 is reduced, and a rapid increase in DC current is suppressed.

  On the other hand, when the rotation speed of the three-phase AC motor 3 rapidly decreases due to disturbance such as a change in road surface condition, a current flows through the reactor 10b from the high pressure side to the low pressure side, and the reactor 10b is magnetically saturated.

  The dq axis voltage command adjusting means 120e calculates an adjustment command for increasing the q axis voltage command Vq * when the current flows from the high voltage side to the low voltage side and the reactor 10b is magnetically saturated. When the reactor 10b is magnetically saturated, the dq-axis voltage command calculating unit 121g increases the q-axis voltage command Vq * based on the adjustment command calculated by the dq-axis voltage command adjusting unit 120e. As the q-axis voltage command Vq * increases, the three-phase voltage commands Vu *, Vv *, and Vw * increase. Finally, the AC power supplied from the inverter 11 to the three-phase AC motor 3 increases. Thereby, the electric power regenerated from the three-phase AC motor 3 via the inverter 11 is reduced, and a rapid increase in DC voltage can be suppressed.

  Finally, specific effects will be described. According to the third embodiment, the AC power supplied from the inverter 11 to the three-phase AC motor 3 can be reliably increased or decreased by increasing or decreasing the q-axis voltage command Vq * by the dq-axis voltage command calculating unit 120g.

  In the above-described embodiment, an example in which only the q-axis voltage command Vq * is adjusted is described, but the present invention is not limited to this. It is sufficient that at least one of the d-axis voltage command Vd * and the q-axis voltage command Vq * can be adjusted. Even in this case, the AC power output from the inverter 11 to the three-phase AC motor 3 can be increased or decreased.

(Fourth embodiment)
Next, FIG. 5 shows a block diagram of a control circuit in the fourth embodiment. Here, only the inverter power adjustment means and the inverter control means, which are different from the motor control device according to the first embodiment, will be described, and the description of the common parts other than the necessary parts will be omitted. In addition, the same code | symbol is attached | subjected and demonstrated to the element same as the said embodiment.

  First, a specific structure will be described. As shown in FIG. 5, the inverter power adjustment means 120 includes a reactor current detection means 120a, a reactor magnetic saturation determination means 120b, and a three-phase shaft voltage command adjustment means 120f.

  The three-phase voltage command adjusting unit 120f calculates an adjustment command based on the determination result of the reactor magnetic saturation determination unit 120b. The three-phase voltage command adjusting means 120f calculates an adjustment command for reducing the three-phase voltage commands Vu *, Vv *, and Vw * when current flows from the low voltage side to the high voltage side and the reactor 10b is magnetically saturated. To do. Further, when the current flows from the high voltage side to the low voltage side and the reactor 10b is magnetically saturated, an adjustment command for increasing the three-phase voltage commands Vu *, Vv *, and Vw * is calculated.

  The inverter control unit 121 includes an inverter input voltage detection unit 121a, a motor rotation position detection unit 121b, a motor rotation number calculation unit 121c, a dq axis current command calculation unit 121d, a motor current detection unit 121e, and a dq axis current calculation. It comprises means 121f, dq-axis voltage command calculation means 121g, three-phase voltage command calculation means 121h, inverter PWM signal generation means 121i, and inverter gate driver 121j.

  Based on the inverter input voltage Vinv calculated by the inverter input voltage detection means 121a and the motor rotation speed Nmot calculated by the motor rotation speed calculation means 121c, the dq-axis current command calculation means 121d is a motor torque command output from the vehicle ECU. Trq * is converted into a value suitable for arithmetic processing, and two-phase conversion is performed to calculate d-axis and q-axis current commands Id * and Iq *.

  The three-phase voltage command calculation means 121h uses the d-axis and q-axis voltage commands Vd * and Vq * calculated by the dq-axis voltage command calculation means 121g as the rotation angle θ of the three-phase AC motor 3 calculated by the motor rotation position detection means 121b. Based on the two-phase three-phase conversion, three-phase voltage commands Vu *, Vv *, Vw * are calculated. Further, when the reactor 10b is magnetically saturated, the three-phase voltage commands Vu *, Vv *, and Vw * are adjusted based on the adjustment command calculated by the three-phase shaft voltage command adjusting means 120f.

  Next, a specific operation will be described. When the rotational speed of the three-phase AC motor 3 increases rapidly due to a disturbance such as a change in road surface condition, a current flows through the reactor 10b from the low pressure side to the high pressure side, and the reactor 10b is magnetically saturated.

  The three-phase voltage command adjusting means 120f calculates an adjustment command for reducing the three-phase voltage commands Vu *, Vv *, and Vw * when current flows from the low voltage side to the high voltage side and the reactor 10b is magnetically saturated. To do. When the reactor 10b is magnetically saturated, the three-phase voltage command calculation unit 121h decreases the three-phase voltage commands Vu *, Vv *, and Vw * based on the adjustment command calculated by the three-phase voltage command adjustment unit 120f. . As the three-phase voltage commands Vu *, Vv *, and Vw * decrease, the AC power supplied from the inverter 11 to the three-phase AC motor 3 finally decreases. As a result, an increase in output due to a rapid increase in the rotational speed of the three-phase AC motor 3 is reduced, and a rapid increase in DC current is suppressed.

  On the other hand, when the rotation speed of the three-phase AC motor 3 rapidly decreases due to disturbance such as a change in road surface condition, a current flows through the reactor 10b from the high pressure side to the low pressure side, and the reactor 10b is magnetically saturated.

  The three-phase voltage command adjusting means 120f calculates an adjustment command for increasing the three-phase voltage commands Vu *, Vv *, and Vw * when current flows from the high voltage side to the low voltage side and the reactor 10b is magnetically saturated. To do. When the reactor 10b is magnetically saturated, the three-phase voltage command calculation unit 121h increases the three-phase voltage commands Vu *, Vv *, and Vw * based on the adjustment command calculated by the three-phase voltage command adjustment unit 120f. . As the three-phase voltage commands Vu *, Vv *, and Vw * increase, finally, the AC power supplied from the inverter 11 to the three-phase AC motor 3 increases. Thereby, the electric power regenerated from the three-phase AC motor 3 via the inverter 11 is reduced, and a rapid increase in DC voltage can be suppressed.

  Finally, specific effects will be described. According to the fourth embodiment, by adjusting the three-phase voltage commands Vu *, Vv *, and Vw * by the three-phase voltage command adjusting means 120f, the AC power supplied from the inverter 11 to the three-phase AC motor 3 is surely obtained. It can be increased or decreased.

(Fifth embodiment)
Next, FIG. 6 shows a block diagram of a control circuit in the fourth embodiment. Here, only the step-up / step-down converter voltage adjusting means, the dq-axis current command calculating means of the inverter control means, and the output voltage command means of the step-up / down converter control means, which are different from the motor control device in the first embodiment, will be described. Description of the common parts is omitted except for the necessary parts. In addition, the same code | symbol is attached | subjected and demonstrated to the element same as the said embodiment.

  First, a specific structure will be described. As shown in FIG. 6, the step-up / down converter voltage adjusting unit 123 determines whether or not the reactor 10 b is magnetically saturated from the reactor current of the step-up / down converter 10. An adjustment command for adjusting the voltage of the pressure converter 10 is output. The step-up / down converter voltage adjusting unit 123 includes a reactor current detecting unit 123a, a reactor magnetic saturation determining unit 123b, and an output voltage command adjusting unit 123c.

  Reactor current detection means 123a is connected to both ends of reactor current detection resistor 10c, and calculates reactor current IL flowing through reactor 10b based on the voltage at both ends of reactor current detection resistor 10c.

  Reactor magnetic saturation determination means 123b calculates a change of reactor current IL with respect to time. And when the magnitude | size of the change with respect to the time of the reactor electric current IL is larger than the preset threshold value, it determines with the reactor 10b being magnetically saturated. Furthermore, the reactor magnetic saturation determination means 123b determines the direction of the current flowing through the reactor 10b from the polarity of the reactor current IL calculated by the reactor current detection means 123a.

  The output voltage command adjustment unit 123c calculates an adjustment command based on the determination result of the reactor magnetic saturation determination unit 123b. The output voltage command adjustment means 123c calculates an adjustment command for increasing the output voltage command Vdc * when current flows from the low voltage side to the high voltage side and the reactor 10b is magnetically saturated. Further, when the current flows from the high voltage side to the low voltage side and the reactor 10b is magnetically saturated, an adjustment command for decreasing the output voltage command Vdc * is calculated.

  The inverter control unit 121 includes an inverter input voltage detection unit 121a, a motor rotation position detection unit 121b, a motor rotation number calculation unit 121c, a dq axis current command calculation unit 121d, a motor current detection unit 121e, and a dq axis current calculation. It comprises means 121f, dq-axis voltage command calculation means 121g, three-phase voltage command calculation means 121h, inverter PWM signal generation means 121i, and inverter gate driver 121j.

  Based on the inverter input voltage Vinv calculated by the inverter input voltage detection means 121a and the motor rotation speed Nmot calculated by the motor rotation speed calculation means 121c, the dq-axis current command calculation means 121d is a motor torque command output from the vehicle ECU. Trq * is converted into a value suitable for arithmetic processing, and further two-phase conversion is performed to calculate d-axis and q-axis current commands Id * and Iq *.

  The step-up / step-down converter control means 122 includes a motor output calculation means 122a, a DC power supply voltage detection means 122b, an output voltage command calculation means 122c, a converter PWM signal generation means 122d, and a converter gate driver 122e. Yes.

  The output voltage command calculation means 122c is based on the motor output Pmot calculated by the motor output calculation means 122a, the DC power supply voltage Vbat calculated by the DC power supply voltage detection means 122b, and the inverter input voltage Vinv calculated by the inverter input voltage detection means 121a. The output voltage command Vdc * of the buck-boost converter 10 is calculated. Further, when the reactor 10b is magnetically saturated, the output voltage command Vdc * is adjusted based on the adjustment command calculated by the output voltage adjusting means 123c. At the same time, converter PWM signal generator 122d increases the switching frequency of converter gate driver 122e.

  Next, a specific operation will be described. When the rotational speed of the three-phase AC motor 3 increases rapidly due to a disturbance such as a change in road surface condition, a current flows through the reactor 10b from the low pressure side to the high pressure side, and the reactor 10b is magnetically saturated.

  At this time, the reactor current detection means 123a calculates the reactor current IL flowing through the reactor 10b based on the voltage across the reactor current detection resistor 10c. Reactor magnetic saturation determination means 123b calculates the change of reactor current IL with respect to time and compares it with a preset threshold value. Reactor 10b is magnetically saturated, and the magnitude of change with respect to time of the current flowing through reactor 10b is larger than when magnetic saturation is not achieved. Therefore, by appropriately setting the threshold value, the reactor magnetic saturation determination unit 123b can determine that the reactor 10b is magnetically saturated. Furthermore, the reactor magnetic saturation determination means 123b determines that the current flows through the reactor 10b from the low voltage side to the high voltage side based on the polarity of the reactor current IL.

  The output voltage command adjustment means 123c calculates an adjustment command for increasing the output voltage command Vdc * when current flows from the low voltage side to the high voltage side and the reactor 10b is magnetically saturated. When the reactor 10b is magnetically saturated, the output voltage command calculation unit 122c increases the output voltage command Vdc * based on the adjustment command calculated by the output voltage command adjustment unit 123c. At the same time, converter PWM signal generation means 122d increases the switching signal frequency of converter gate driver 122e, and relaxes magnetic saturation of reactor 10b. As the output voltage command Vdc * increases, the DC voltage on the high-voltage side of the buck-boost converter 10 finally increases, and a sudden increase in DC current is suppressed.

  On the other hand, when the rotation speed of the three-phase AC motor 3 rapidly decreases due to disturbance such as a change in road surface condition, a current flows through the reactor 10b from the high pressure side to the low pressure side, and the reactor 10b is magnetically saturated.

  At this time, the reactor current detection means 123a calculates the reactor current IL flowing through the reactor 10b based on the voltage across the reactor current detection resistor 10c. Reactor magnetic saturation determination means 123b calculates the change of reactor current IL with respect to time and compares it with a preset threshold value. Reactor 10b is magnetically saturated, and the magnitude of change with respect to time of the current flowing through reactor 10b is larger than when magnetic saturation is not achieved. Therefore, by appropriately setting the threshold value, the reactor magnetic saturation determination unit 123b can determine that the reactor 10b is magnetically saturated. Furthermore, the reactor magnetic saturation determination means 123b determines that the current flows through the reactor 10b from the high voltage side to the low voltage side based on the polarity of the reactor current IL.

  The output voltage command adjusting means 123c calculates an adjustment command for decreasing the output voltage command Vdc * when a current flows from the high voltage side to the low voltage side and the reactor 10b is magnetically saturated. When the reactor 10b is magnetically saturated, the output voltage command calculation unit 122c decreases the output voltage command Vdc * based on the adjustment command calculated by the output voltage command adjustment unit 123c. At the same time, converter PWM signal generation means 122d increases the switching signal frequency of converter gate driver 122e, and relaxes magnetic saturation of reactor 10b. By decreasing the output voltage command Vdc *, the DC voltage on the high voltage side of the buck-boost converter 10 is finally decreased, and a rapid increase in the DC voltage can be suppressed.

  Finally, specific effects will be described. According to the fifth embodiment, it is possible to reliably determine the beginning of the magnetic saturation of the reactor 10b by comparing the magnitude of the change of the current flowing through the reactor 10b with respect to time with a predetermined threshold value. Furthermore, the occurrence of overcurrent or overvoltage can be suppressed by increasing or decreasing the high-voltage DC voltage of the buck-boost converter 10 based on the direction of the current flowing through the reactor 10b. Therefore, the inverter 11 and the buck-boost converter 10 can be reliably protected without increasing the current capacity and breakdown voltage of the components.

  In the first to fifth embodiments described above, an example in which only the AC power supplied from the inverter 11 to the three-phase AC motor 3 is adjusted, or an example in which only the DC voltage on the high voltage side of the buck-boost converter 10 is adjusted. However, it is not limited to this. You may comprise combining these.

  Moreover, although the example which used IGBT as a switching element which comprises the inverter 11 is given in the 1st-5th embodiment mentioned above, it is not restricted to this. A SiC-MOSFET may be used as the switching element. In this case, the responsiveness of the inverter can be further improved and the loss can be further reduced.

  Furthermore, in the first to fifth embodiments described above, the example in which the reactor current detection resistor 10c is connected between the step-up / step-down IGBTs 10d and 10e connected in series with the reactor 10b is given. It is not limited.

  As shown in FIG. 7A, the other end of the reactor 10b is connected to the connection point of the step-up / down IGBTs 10d and 10e connected in series, and between the emitter of the step-up / down IGBT 10e and the other end of the low-voltage side smoothing capacitor 10a. In addition, a reactor current detection resistor 10c may be connected. Further, as shown in FIG. 7B, the other end of the reactor 10b is connected to the collector of the step-up / down IGBT 10e, and a reactor current detection resistor 10c is connected between this connection point and the emitter of the step-up / down IGBT 10d. It may be. Furthermore, you may use the current sensor which can detect an electric current magnetically.

  Increasing the switching signal frequency of the converter gate driver 122e is not limited to simply increasing the switching signal frequency of the converter gate driver 122e, but lowering the switching signal frequency of the inverter gate driver 121j. In this case, the switching signal frequency of the converter gate driver 122e is relatively increased as compared with the switching signal frequency of the inverter gate driver 121j.

The circuit diagram of the motor control apparatus in 1st Embodiment is shown. The block diagram of the control circuit in 1st Embodiment is shown. The block diagram of the control circuit in 2nd Embodiment is shown. The block diagram of the control circuit in 3rd Embodiment is shown. The block diagram of the control circuit in 4th Embodiment is shown. The block diagram of the control circuit in 5th Embodiment is shown. Another example of installation of the reactor current detection resistor is shown. The waveform of the reactor current which flows into a reactor is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Motor control apparatus, 10 ... Buck-boost converter, 10a ... Low voltage side smoothing capacitor, 10b ... Reactor, 10c ... Reactor current detection resistor, 10d, 10e ... For buck-boost IGBT (switching element), 10f, 10g ... flywheel diode, 10h ... high-voltage side smoothing capacitor, 11 ... inverter, 11a-11f ... IGBT for inverter (switching element), 11g-11l ..Flywheel diode, 12 ... Control circuit, 120 ... Inverter power adjustment means, 120a ... Reactor current detection means, 120b ... Reactor magnetic saturation determination means (magnetic saturation detection means), 120c Dq-axis current command adjusting means, 120d... Dq-axis current adjusting means, 120e. Voltage command adjusting means, 120f ... three-phase voltage command adjusting means, 121 ... inverter control means, 121a ... inverter input voltage detecting means, 121b ... motor rotation position detecting means, 121c ... motor rotation Number calculation means, 121d... Dq axis current command calculation means, 121e... Motor current detection means, 121f... Dq axis current calculation means, 121g... Dq axis voltage command calculation means, 121h. Phase voltage command calculation means, 121i... Inverter PWM signal generation means, 121j... Inverter gate driver, 122... Buck-boost converter control means, 122a... Motor output calculation means, 122b. Power supply voltage detection means, 122c... Output voltage command calculation means, 122d... PWM signal generation means for converter, 12 e ... Converter gate driver, 123 ... Buck-boost converter voltage adjustment means, 123a ... Reactor current detection means, 123b ... Reactor magnetic saturation determination means, 123c ... Output voltage command adjustment means, 2 ... DC power supply, 3 ... three-phase AC motor, 3a ... rotational position detection sensor, 4a, 4b ... current sensor

Claims (9)

A reactor and a switching element are provided to control the current flowing through the reactor by switching the switching element to boost the low-voltage side DC voltage and output it to the high-voltage side, and to step down the high-voltage side DC voltage The buck-boost converter that outputs to the low-voltage side, and the buck-boost converter control means that controls the DC voltage on the high-voltage side and the DC voltage on the low-voltage side that are output from the buck-boost converter by controlling the switching operation of the switching element. And converting DC power output from the high voltage side of the buck-boost converter into AC power and outputting it to a three-phase AC motor, and converting AC power generated by the three-phase AC motor into DC power. An inverter that outputs to the high voltage side of the buck-boost converter, and an inverter that controls the AC power output from the inverter The motor control apparatus and a control means,
Magnetic saturation detection means for detecting magnetic saturation of the reactor, and inverter power adjustment means for adjusting AC power output from the inverter to the three-phase AC motor in the magnetic saturation period detected by the magnetic saturation detection means, Or a motor control device comprising at least one of step-up / down converter voltage adjusting means for adjusting a DC voltage on the high-voltage side of the step-up / down converter. The magnetic saturation detection means determines that the magnetic saturation of the reactor has started when the magnitude of the change of the current flowing through the reactor with respect to time is greater than a predetermined threshold, and at this time, the inverter power adjustment means flows to the reactor. When the current direction is from the low-voltage side to the high-voltage side, the AC power output from the inverter to the three-phase AC motor is reduced. When the current direction is from the high-voltage side to the low-voltage side, the inverter to the three-phase Increase the AC power output to the AC motor,
The step-up / step-down converter voltage adjusting means determines that the magnetic saturation of the reactor has started when the magnitude of change with respect to time of the current flowing through the reactor is greater than the predetermined threshold, and at this time, the direction of the current flowing through the reactor is The DC voltage on the high-voltage side of the buck-boost converter is increased when the direction is from the low-voltage side to the high-voltage side, and the DC voltage on the high-voltage side of the buck-boost converter is decreased when the direction is from the high-voltage side to the low-voltage side. The motor control device according to claim 1, wherein at the same time, a switching frequency of the switching element constituting the buck-boost converter is increased.   The inverter control means converts d-axis current command and q-axis current command into two-phase by converting a motor torque command inputted from the outside into two phases, and three-phase AC motor phase current. A dq-axis current calculation means for calculating a d-axis current and a q-axis current by phase-to-phase conversion; and a d-axis voltage based on the d-axis current command, the q-axis current command, the d-axis current, and the q-axis current. A dq-axis voltage command calculation means for calculating a command and a q-axis voltage command; a three-phase voltage command calculation means for calculating a three-phase voltage command by performing two-phase three-phase conversion on the d-axis voltage command and the q-axis voltage command; The motor control device according to claim 1, further comprising:   4. The motor control device according to claim 3, wherein the inverter power adjustment means adjusts at least one of the d-axis current command and the q-axis current command in the dq-axis current command calculation means.   4. The motor control device according to claim 3, wherein the inverter power adjustment means adjusts at least one of the d-axis current and the q-axis current in the dq-axis current calculation means.   4. The motor control device according to claim 3, wherein the inverter power adjustment means adjusts at least one of the d-axis voltage command and the q-axis voltage command in the dq-axis voltage command calculation means.   4. The motor control device according to claim 3, wherein the inverter power adjustment means adjusts the three-phase voltage command in the three-phase voltage command calculation means.   The motor control device according to claim 1, wherein the inverter has a switching element made of IGBT or SiC-MOSFET.   9. The motor control device according to claim 1, wherein the motor control device controls a three-phase AC motor mounted on the vehicle.

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