JP2005354763A - Voltage converter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a voltage converter for implementing a stable feedback control even if a temperature fluctuates. <P>SOLUTION: A controller 30 adjusts a control gain during the feedback control in response to the temperature Tc of a capacitor C2 received from a temperature sensor 13B so as to match an output voltage Vm with a voltage instruction. The controller 30 adjusts the control gain so as to decrease it as the temperature Tc of the capacitor C2 decreases. The controller 30 generates a signal PWC for implementing the feedback control for a voltage boosting converter 12 so as to match the output voltage Vm with the voltage instruction by using the adjusted control gain, and outputs the generated signal PWC to NPN transistors Q1, Q2 in the voltage boosting converter 12. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a voltage converter that converts a DC voltage from a DC power source into a command voltage.

  Recently, hybrid vehicles and electric vehicles have attracted a great deal of attention as environmentally friendly vehicles. Some hybrid vehicles have been put into practical use.

  This hybrid vehicle is a vehicle that uses a DC power source, an inverter, and a motor driven by the inverter as a power source in addition to a conventional engine. In other words, a power source is obtained by driving the engine, a DC voltage from a DC power source is converted into an AC voltage by an inverter, and a motor is rotated by the converted AC voltage to obtain a power source. An electric vehicle is a vehicle that uses a DC power source, an inverter, and a motor driven by the inverter as a power source.

  In such a hybrid vehicle or electric vehicle, a system has also been proposed in which a DC voltage from a DC power source is boosted by a boost converter and the boosted DC voltage is supplied to an inverter that drives a motor (Patent Document 1).

In the system disclosed in Patent Document 1, when feedback control of the boost converter is performed so that the output voltage matches the command voltage, an error between the command voltage and the output voltage is calculated, and according to the calculated error. The control gain is adjusted, and further feedback control is performed using the adjusted control gain so that the output voltage matches the command voltage.
JP 2003-309997 A JP 2001-57704 A JP 2001-119809 A JP 2002-186108 A

  However, in the feedback control disclosed in Patent Document 1, the control gain (proportional gain and integral gain) in the feedback control is not determined in consideration of the capacitance of the capacitor provided on the input side of the inverter that drives the motor. Therefore, when feedback control is performed using the control gain set at room temperature when the capacitance of the capacitor is reduced due to a decrease in temperature, the control gain is apparently increased and feedback control of the output voltage is diverged. There is a problem.

  Therefore, the present invention has been made to solve such a problem, and an object of the present invention is to provide a voltage converter capable of stable feedback control even when the temperature fluctuates.

  A voltage converter according to the present invention is a voltage converter that converts a DC voltage from a DC power source into an output voltage so that the output voltage matches a command voltage, and includes a capacitor, a voltage converter, and a control means. Prepare. The capacitive element is provided on the input side of the drive circuit that drives the load. The voltage converter converts a DC voltage from a DC power source into an output voltage and outputs the output voltage to the capacitive element. The control means adjusts the control gain when performing feedback control of the voltage converter so that the output voltage matches the command voltage according to the temperature of the capacitive element, and the output voltage becomes the command voltage using the adjusted control gain. The voltage converter is feedback controlled so as to match.

  Preferably, the control means adjusts the control gain so as to decrease as the temperature of the capacitive element decreases.

  Preferably, the control means adjusts the control gain so that the response characteristic of the output voltage with respect to the temperature variation of the capacitive element is substantially the same as a suitable response characteristic.

  Preferably, the suitable response characteristic is a response characteristic of the output voltage when the temperature of the capacitive element is normal temperature.

  Preferably, the control means sets the capacitance element so that the response characteristic of the output voltage is substantially the same as the suitable response characteristic when the control gain set when the temperature of the capacitive element is normal temperature is set to a suitable control gain. The control gain is adjusted by multiplying a suitable control gain by a correction coefficient determined according to the temperature of the current.

  Preferably, the control means holds a map indicating a relationship between the temperature of the capacitive element and the correction coefficient, extracts a correction coefficient corresponding to the temperature of the capacitive element with reference to the map, and extracts the extracted correction coefficient. The control gain is adjusted by multiplying a suitable control gain.

  Preferably, the suitable control gain comprises a suitable proportional gain and a suitable integral gain. Then, the control means adjusts the control gain by multiplying both a suitable proportional gain and a suitable integral gain by the correction coefficient.

  The voltage converter according to the present invention is a voltage converter that converts a DC voltage from a DC power source into an output voltage so that the output voltage matches the command voltage. The capacitor, a voltage converter, Control means. The capacitive element is provided on the input side of the drive circuit that drives the load. The voltage converter converts a DC voltage from a DC power source into the output voltage and outputs the output voltage to the capacitive element. The control means adjusts the control gain when feedback controlling the voltage converter so that the output voltage matches the command voltage according to the temperature of the capacitive element and the temperature of the DC power supply, and outputs using the adjusted control gain. The voltage converter is feedback controlled so that the voltage matches the command voltage.

  Preferably, the control means adjusts the control gain so as to decrease as the temperature of the capacitive element decreases, and adjusts the control gain so as to increase as the temperature of the DC power supply decreases.

  Preferably, the control means adjusts the control gain so that the response characteristic of the output voltage with respect to the temperature variation of the capacitive element and the DC power supply becomes substantially the same as a suitable response characteristic.

  Preferably, the suitable response characteristic is a response characteristic of the output voltage when the temperature of the capacitive element and the DC power supply is normal temperature.

  Preferably, the control means sets the response characteristic of the output voltage to be substantially the same as the suitable response characteristic when the control gain set when the temperature of the capacitive element and the DC power supply is normal temperature is set as a suitable control gain. The control gain is adjusted by multiplying a suitable control gain by the first and second correction coefficients respectively determined according to the temperature of the capacitive element and the temperature of the DC power source.

  Preferably, the control means holds a first map indicating a relationship between the temperature of the capacitive element and the first correction coefficient, and a second map indicating a relationship between the temperature of the DC power source and the second correction coefficient. The first correction coefficient corresponding to the temperature of the capacitive element and the second correction coefficient corresponding to the temperature of the DC power supply are extracted with reference to the first and second maps, respectively, and the extracted first and The control gain is adjusted by multiplying a suitable control gain by the second correction coefficient.

  Preferably, the suitable control gain comprises a suitable proportional gain and a suitable integral gain. Then, the control means adjusts the control gain by multiplying both the suitable proportional gain and the suitable integral gain by the first and second correction coefficients.

  Preferably, the capacitive element is an electrolytic capacitor.

  In the voltage conversion device according to the present invention, the control means adjusts the control gain when feedback control is performed so that the output voltage matches the command voltage according to the temperature of the capacitive element, and outputs using the adjusted control gain. Since the voltage converter is feedback controlled so that the voltage matches the command voltage, feedback control is performed in which a control gain suitable for the temperature of the capacitive element is set.

  Therefore, according to the present invention, stable feedback control can be performed even if the temperature of the capacitive element varies.

  In the voltage converter according to the present invention, the control means adjusts the control gain when performing feedback control so that the output voltage matches the command voltage according to the temperature of the DC power supply and the temperature of the capacitive element, and the adjustment Since the voltage converter is feedback-controlled using the control gain so that the output voltage matches the command voltage, feedback control is performed in which a control gain suitable for the temperature of the DC power source and the temperature of the capacitive element is set.

  Therefore, according to the present invention, stable feedback control can be performed even if the temperature of the DC power supply and / or the temperature of the capacitive element fluctuates.

  Embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

[Embodiment 1]
FIG. 1 is a schematic diagram of a motor drive device including a voltage conversion device according to Embodiment 1 of the present invention. Referring to FIG. 1, motor drive device 100 including the voltage conversion device according to the first embodiment includes DC power supply B, voltage sensors 10, 13A, system relays SR1, SR2, capacitors C1, C2, and a booster. Converter 12, temperature sensor 13 </ b> B, inverters 14 and 31, current sensors 24 and 28, and control device 30 are provided. AC motor M1 is a drive motor for generating torque for driving drive wheels of a hybrid vehicle or an electric vehicle. The AC motor M2 is a motor that has a function of a generator driven by an engine, operates as an electric motor for the engine, and can start the engine, for example.

  Boost converter 12 includes a reactor L1, NPN transistors Q1, Q2, and diodes D1, D2. Reactor L1 has one end connected to the power supply line of DC power supply B, and the other end connected to an intermediate point between NPN transistor Q1 and NPN transistor Q2, that is, between the emitter of NPN transistor Q1 and the collector of NPN transistor Q2. The NPN transistors Q1 and Q2 are connected in series between the power supply line and the earth line. The collector of NPN transistor Q1 is connected to the power supply line, and the emitter of NPN transistor Q2 is connected to the ground line. In addition, diodes D1 and D2 that allow current to flow from the emitter side to the collector side are arranged between the collectors and emitters of the NPN transistors Q1 and Q2, respectively.

  Inverter 14 includes a U-phase arm 15, a V-phase arm 16, and a W-phase arm 17. U-phase arm 15, V-phase arm 16, and W-phase arm 17 are provided in parallel between the power supply line and ground.

  The U-phase arm 15 includes NPN transistors Q3 and Q4 connected in series, the V-phase arm 16 includes NPN transistors Q5 and Q6 connected in series, and the W-phase arm 17 includes NPN transistors Q7 and Q7 connected in series. Consists of Q8. Further, diodes D3 to D8 that flow current from the emitter side to the collector side are connected between the collectors and emitters of the NPN transistors Q3 to Q8, respectively.

  An intermediate point of each phase arm is connected to each phase end of each phase coil of AC motor M1. In other words, AC motor M1 is a three-phase permanent magnet motor, and is configured such that one end of three coils of U, V, and W phases is commonly connected to the middle point, and the other end of the U-phase coil is NPN transistor Q3. The other end of the V-phase coil is connected to the intermediate point of NPN transistors Q5 and Q6, and the other end of the W-phase coil is connected to the intermediate point of NPN transistors Q7 and Q8, respectively.

  The inverter 31 has the same configuration as the inverter 14. And the intermediate point of each phase arm of inverter 31 is connected to each phase end of each phase coil of AC motor M2. That is, the AC motor M2 is also a three-phase permanent magnet motor, and is configured such that one end of three U, V, and W phase coils is commonly connected to the midpoint, and the other end of the U phase coil is the NPN of the inverter 31. The other end of the V-phase coil is connected to the intermediate point of the NPN transistors Q5 and Q6 of the inverter 31 and the other end of the W-phase coil is connected to the intermediate point of the NPN transistors Q7 and Q8 of the inverter 31, respectively. Has been.

  The DC power source B is composed of a secondary battery such as nickel metal hydride or lithium ion. The voltage sensor 10 detects the voltage Vb output from the DC power supply B and outputs the detected voltage Vb to the control device 30. System relays SR1 and SR2 are turned on / off by signal SE from control device 30. More specifically, system relays SR1 and SR2 are turned on by H (logic high) level signal SE from control device 30, and are turned off by L (logic low) level signal SE from control device 30. Capacitor C1 smoothes DC voltage Vb supplied from DC power supply B, and supplies the smoothed DC voltage to boost converter 12.

  Boost converter 12 boosts the DC voltage supplied from capacitor C1 and supplies the boosted voltage to capacitor C2. More specifically, when boost converter 12 receives signal PWC from control device 30, boost converter 12 boosts the DC voltage according to the period during which NPN transistor Q2 is turned on by signal PWC and supplies the boosted voltage to capacitor C2. When boost converter 12 receives signal PWC from control device 30, boost converter 12 steps down the DC voltage supplied from inverter 14 (or inverter 31) via capacitor C 2 and charges DC power supply B.

  The capacitor C2 is composed of an electrolytic capacitor or a film capacitor. Capacitor C2 smoothes the DC voltage from boost converter 12, and supplies the smoothed DC voltage to inverters 14 and 31 via nodes N1 and N2. The voltage sensor 13A detects the voltage across the capacitor C2, that is, the output voltage Vm of the boost converter 12 (corresponding to the input voltage to the inverters 14 and 31, the same applies hereinafter), and controls the detected output voltage Vm. Output to device 30. The temperature sensor 13B detects the temperature Tc of the capacitor C2, and outputs the detected temperature Tc to the control device 30.

  When the DC voltage is supplied from the capacitor C2, the inverter 14 converts the DC voltage into an AC voltage based on the signal PWM1 from the control device 30, and drives the AC motor M1. As a result, AC motor M1 is driven so as to generate torque specified by torque command value TR1. Further, the inverter 14 converts the AC voltage generated by the AC motor M1 into a DC voltage based on the signal PWM1 from the control device 30 during regenerative braking of the hybrid vehicle or electric vehicle on which the motor drive device 100 is mounted, The converted DC voltage is supplied to boost converter 12 via capacitor C2. Note that regenerative braking here refers to braking with regenerative power generation when the driver driving a hybrid vehicle or electric vehicle performs foot braking, or turning off the accelerator pedal while driving, although the foot brake is not operated. This includes decelerating the vehicle (or stopping acceleration) while generating regenerative power.

  Current sensor 24 detects motor current MCRT1 flowing through AC motor M1, and outputs the detected motor current MCRT1 to control device 30.

  When the DC voltage is supplied from the capacitor C2, the inverter 31 converts the DC voltage into an AC voltage based on the signal PWM2 from the control device 30 and drives the AC motor M2. As a result, AC motor M2 is driven so as to generate torque specified by torque command value TR2. Further, the inverter 31 converts the AC voltage generated by the AC motor M2 into a DC voltage based on the signal PWM2 from the control device 30 during regenerative braking of the hybrid vehicle or electric vehicle on which the motor drive device 100 is mounted, The converted DC voltage is supplied to boost converter 12 via capacitor C2.

  Current sensor 28 detects motor current MCRT2 flowing through AC motor M2, and outputs the detected motor current MCRT2 to control device 30.

  The control device 30 includes torque command values TR1, 2 and motor rotational speeds MRN1, 2 input from an externally provided ECU (Electrical Control Unit), a voltage Vb from the voltage sensor 10, a voltage Vm from the voltage sensor 13, Based on motor current MCRT1 from current sensor 24 and motor current MCRT2 from current sensor 28, a signal PWC for driving boost converter 12 and a signal PWM1 for driving inverter 14 (or inverter 31) by a method described later. (Or signal PWM2) is generated, and the generated signal PWC and signal PWM1 (or signal PWM2) are output to boost converter 12 and inverter 14 (or inverter 31), respectively.

  Signal PWC is a signal for driving boost converter 12 when boost converter 12 converts the DC voltage from capacitor C1 to output voltage Vm. When boost converter 12 converts a DC voltage into output voltage Vm, control device 30 performs feedback control on output voltage Vm, and drives boost converter 12 so that output voltage Vm becomes voltage command Vdc_com. A signal PWC is generated. A method for generating the signal PWC will be described later.

  Control device 30 also generates signal PWM1 (or signal PWM2) for converting the AC voltage generated by AC motor M1 (or AC motor M2) into a DC voltage in the regenerative braking mode of the hybrid vehicle or electric vehicle. And output to the inverter 14 (or the inverter 31). In this case, the NPN transistors Q3 to Q8 of the inverter 14 (or the inverter 31) are switching-controlled by the signal PWM1 (or the signal PWM2), and the inverter 14 (or the inverter 31) generates power with the AC motor M1 (or the AC motor M2). The AC voltage thus converted is converted into a DC voltage and supplied to the boost converter 12.

  Further, control device 30 generates signal PWC for stepping down the DC voltage supplied from inverter 14 (or inverter 31) when the hybrid vehicle or the electric vehicle is in a regenerative braking mode, and uses the generated signal PWC as a boost converter. 12 is output. As a result, the AC voltage generated by AC motor M1 (or AC motor M2) is converted into a DC voltage, stepped down, and supplied to DC power supply B.

  Furthermore, control device 30 generates signal SE for turning on / off system relays SR1, SR2 and outputs the signal SE to system relays SR1, SR2.

  FIG. 2 is a functional block diagram of the control device 30 shown in FIG. Referring to FIG. 2, control device 30 includes inverter control means 301 and converter control means 302. Inverter control means 301 generates signal PWM1 for driving inverter 14 based on motor current MCRT1, torque command value TR1 and output voltage Vm of boost converter 12 by a method described later, and generates generated signal PWM1 as an inverter. 14 to NPN transistors Q3 to Q8.

  Further, inverter control means 301 generates signal PWM2 for driving inverter 31 based on motor current MCRT2, torque command value TR2 and output voltage Vm of boost converter 12 by a method described later, and the generated signal PWM2 Is output to NPN transistors Q3 to Q8 of inverter 31.

  The converter control means 302 outputs the AC motor M1 (or AC motor M2) according to the method described later when driving the AC motor M1 (or AC motor M2) based on the motor rotation speeds MRN1, 2, torque command values TR1, 2, Vb, Vm and temperature Tc. A signal PWC for feedback control of boost converter 12 is generated so that voltage Vm matches voltage command Vdc_com, and the generated signal PWC is output to NPN transistors Q 1 and Q 2 of boost converter 12.

  This signal PWC steps down the DC voltage Vb supplied from the DC power supply B so that the output voltage Vm becomes the voltage command Vdc_com, or the DC voltage supplied from the inverter 14 (or the inverter 31). It is a signal for. Therefore, boost converter 12 performs a boost operation or a step-down operation in accordance with signal PWC. Thus, the boost converter 12 has a bidirectional converter function.

  FIG. 3 is a functional block diagram of the inverter control means 301 shown in FIG. Referring to FIG. 3, inverter control means 301 includes a motor control phase voltage calculation unit 40 and an inverter PWM signal conversion unit 42.

  Motor control phase voltage calculation unit 40 calculates a voltage to be applied to each phase of AC motor M1 based on output voltage Vm of boost converter 12, motor current MCRT1 and torque command value TR1, and outputs output voltage Vm and motor current MCRT2. And a voltage to be applied to each phase of AC motor M2 based on torque command value TR2. The motor control phase voltage calculation unit 40 then outputs the calculated voltage for the AC motor M1 or M2 to the inverter PWM signal conversion unit 42.

  When receiving the voltage for AC motor M1 from motor control phase voltage calculation unit 40, inverter PWM signal conversion unit 42 actually turns on / off each NPN transistor Q3-Q8 of inverter 14 based on the received voltage. A signal PWM1 to be turned off is generated, and the generated signal PWM1 is output to the NPN transistors Q3 to Q8 of the inverter 14. Further, when the inverter PWM signal conversion unit 42 receives the voltage for the AC motor M2 from the motor control phase voltage calculation unit 40, the inverter PWM signal conversion unit 42 actually sets the NPN transistors Q3 to Q8 of the inverter 31 based on the received voltage. The on / off signal PWM2 is generated, and the generated signal PWM2 is output to the NPN transistors Q3 to Q8 of the inverter 31.

  Thereby, each of the NPN transistors Q3 to Q8 of the inverter 14 or 31 is subjected to switching control, and controls the current flowing through each phase of the AC motor M1 or M2 so that the AC motor M1 or M2 outputs the commanded torque. In this way, the motor drive current is controlled, and a motor torque corresponding to the torque command values TR1 and TR2 is output.

  FIG. 4 is a functional block diagram of converter control means 302 shown in FIG. Referring to FIG. 4, converter control means 302 includes an inverter input voltage command calculation unit 50, a feedback voltage command calculation unit 52, and a duty ratio conversion unit 54.

  The inverter input voltage command calculation unit 50 calculates the optimum value (target value) of the inverter input voltage, that is, the voltage command Vdc_com, based on the torque command value TR1 (or TR2) and the motor rotational speed MRN1 (or MRN2). The calculated voltage command Vdc_com is output to the feedback voltage command calculation unit 52.

  Feedback voltage command calculation unit 52 receives output voltage Vm of boost converter 12 from voltage sensor 13A, receives temperature Tc of capacitor C2 from temperature sensor 13B, and receives voltage command Vdc_com from inverter input voltage command calculation unit 50. The feedback voltage command calculation unit 52 calculates a deviation ΔVdc between the voltage command Vdc_com and the voltage Vm, and sets a control gain when performing feedback control so that the output voltage Vm matches the voltage command Vdc_com as a temperature Tc of the capacitor C2. The correction is made according to the method described later. Then, feedback voltage command calculation unit 52 calculates feedback voltage command Vdc_com_fb by a method described later based on calculated deviation ΔVdc and the corrected control gain, and duty ratio conversion unit 54 calculates the calculated feedback voltage command Vdc_com_fb. Output to.

  Based on the voltage Vb from the voltage sensor 10 and the feedback voltage command Vdc_com_fb from the feedback voltage command calculation unit 52, the duty ratio conversion unit 54 converts the output voltage Vm from the voltage sensor 13A from the feedback voltage command calculation unit 52. A duty ratio for setting the feedback voltage command Vdc_com_fb is calculated, and a signal PWC for turning on / off the NPN transistors Q1 and Q2 of the boost converter 12 is generated based on the calculated duty ratio. Then, duty ratio converter 54 outputs generated signal PWC to NPN transistors Q1 and Q2 of boost converter 12.

  Note that increasing the on-duty of the NPN transistor Q2 on the lower side of the boost converter 12 increases the power storage in the reactor L1, so that a higher voltage output can be obtained. On the other hand, increasing the on-duty of the upper NPN transistor Q1 reduces the voltage of the power supply line. Therefore, by controlling the duty ratio of the NPN transistors Q1 and Q2, the voltage of the power supply line can be controlled to an arbitrary voltage equal to or higher than the output voltage of the DC power supply B.

  FIG. 5 is a functional block diagram of feedback voltage command calculation unit 52 and duty ratio conversion unit 54 shown in FIG. Referring to FIG. 5, feedback voltage command calculation unit 52 includes a subtracter 521, a gain correction unit 522, and a PI controller 523. Subtractor 521 receives voltage command Vdc_com from inverter input voltage command calculation unit 50 and output voltage Vm from voltage sensor 13A, and subtracts output voltage Vm from voltage command Vdc_com. Then, the subtractor 521 outputs the subtraction result to the PI controller 523 as a deviation ΔVdc (= Vdc_com−Vm).

  The gain correction unit 522 holds a control gain when the temperature Tc of the capacitor C2 is normal temperature, that is, a proportional gain Kpo and an integral gain Kio when the temperature Tc of the capacitor C2 is normal temperature, and the temperature sensor 13B. Receives the temperature Tc of the capacitor C2.

  FIG. 6 is a timing chart of the output voltage Vm. Referring to FIG. 6, when proportional gain Kpo and integral gain Kio are set, output voltage Vm changes according to curve k1, and finally coincides with voltage command Vcd_com which is a target voltage. That is, the output voltage Vm smoothly matches the voltage command Vdc_com without causing the response characteristic of the output voltage Vm to diverge or vibrate.

  Therefore, the proportional gain Kpo and the integral gain Kio are set so that the response characteristic of the output voltage Vm becomes good (that is, the response characteristic of the output voltage Vm) when feedback control is performed so that the output voltage Vm matches the voltage command Vdc_com. Is a gain determined such that the output voltage Vm smoothly matches the voltage command Vdc_com without divergence or vibration.

  Then, the gain correction unit 522 corrects the proportional gain Kpo and the integral gain Kio according to the temperature Tc, and outputs the corrected proportional gain Kp1 and integral gain Ki1 to the PI controller 523.

  FIG. 7 is a graph showing the relationship between the correction coefficient Kc and the temperature Tc of the capacitor C2. The correction coefficient Kc is a correction coefficient for correcting the proportional gain Kpo and the integral gain Kio at normal temperature according to the temperature Tc of the capacitor C2.

  Referring to FIG. 7, correction coefficient Kc changes according to curve k2 with respect to temperature Tc of capacitor C2. More specifically, in the region where the temperature Tc of the capacitor C2 is equal to or higher than the critical temperature Tc_b, the correction coefficient Kc gradually decreases substantially linearly as the temperature Tc of the capacitor C2 decreases, and the temperature Tc of the capacitor C2 is reduced. In the region lower than the critical temperature Tc_b, the correction coefficient Kc decreases rapidly as the temperature Tc of the capacitor C2 decreases. When the temperature Tc of the capacitor C2 is normal temperature Tc_nml, the correction coefficient Kc is “1”. The correction coefficient Kc when the temperature Tc of the capacitor C2 is other than the room temperature Tc_nml is such that the response characteristic of the output voltage Vm at a temperature other than the room temperature Tc_nml is the response characteristic of the output voltage Vm at the room temperature Tc_nml (ie, the curve k1 in FIG. 6). This is a correction coefficient for correcting the proportional gain Kpo and the integral gain Kio so as to substantially coincide with the response characteristic indicated by.

  Referring to FIG. 5 again, the gain correction unit 522 holds the curve k2 shown in FIG. 7 as a map showing the relationship between the correction coefficient Kc and the temperature Tc, and the temperature Tc of the capacitor C2 from the temperature sensor 13B. When received, the correction coefficient Kc corresponding to the received temperature Tc is extracted with reference to the map (curve k2 shown in FIG. 7), and the proportional correction Kpo and the integral gain Kio are respectively multiplied by the extracted correction coefficient Kc. Thus, the proportional gain Kp1 and the integral gain Ki1 used for feedback control of the output voltage Vm are determined. That is, the gain correction unit 522 determines the proportional gain Kp1 and the integral gain Ki1 according to the following equations (1) and (2), respectively.

Kp1 = Kc × Kpo (1)
Ki1 = Kc × Kio (2)
In this way, the gain correction unit 522 corrects the proportional gain Kpo and the integral gain Kio when the temperature Tc of the capacitor C2 is normal temperature Tc_nml by multiplying the correction coefficient Kc determined according to the temperature Tc of the capacitor C2. To do.

  Since the correction coefficient Kc becomes smaller as the temperature Tc of the capacitor C2 decreases as shown in FIG. 7, the gain correction unit 522 generally includes the proportional gain Kp1 and the gain Cp1 as the temperature Tc of the capacitor C2 decreases. The integral gain Ki1 is set low. That is, the gain correction unit 522 adjusts the proportional gain and the integral gain so that the value decreases as the temperature Tc of the capacitor C2 decreases.

  In more detail, the gain correction unit 522 adjusts the proportional gain and the integral gain as follows.

  As described above, since the correction coefficient Kc is “1” when the temperature Tc of the capacitor C2 is the normal temperature Tc_nml, the gain correction unit 522 uses the proportional gain Kp1 and the integral gain Kio at the normal temperature Tc_nml, respectively. And it outputs to PI controller 523 as integral gain Ki1. That is, when the temperature Tc of the capacitor C2 is normal temperature Tc_nml, the gain correction unit 522 determines the proportional gain Kpo and integral gain that are determined in advance so that the output voltage Vm smoothly matches the voltage command Vdc_com according to the curve k1 in FIG. Kio is output to the PI controller 523.

  Further, when the temperature Tc of the capacitor C2 is lower than the normal temperature Tc_nml, the correction coefficient Kc becomes smaller as the temperature Tc decreases, so that the gain correction unit 522 performs the operation at the normal temperature Tc_nml as the temperature Tc decreases. The proportional gain Kp1 and the integral gain Ki1 that are smaller than the proportional gain Kpo and the integral gain Kio are output to the PI controller 523, respectively.

  Further, when the temperature Tc of the capacitor C2 becomes higher than the normal temperature Tc_nml, the correction coefficient Kc increases as the temperature Tc increases. Therefore, the gain correction unit 522 increases the temperature Tc and increases the temperature Tc_nml. The proportional gain Kp1 and the integral gain Ki1 that are larger than the proportional gain Kpo and the integral gain Kio, respectively, are output to the PI controller 523.

  As described above, the correction coefficient Kc when the temperature Tc of the capacitor C2 is other than the room temperature Tc_nml is such that the response characteristic of the output voltage Vm at a temperature other than the room temperature Tc_nml is the response characteristic of the output voltage Vm at the room temperature Tc_nml (that is, This is a correction coefficient for correcting the proportional gain Kpo and the integral gain Kio so as to substantially match the response characteristic indicated by the curve k1 in FIG.

  Accordingly, when the temperature Tc of the capacitor C2 deviates from the normal temperature Tc_nml, the gain correction unit 522 changes the response characteristic of the output voltage Vm at each temperature to the response characteristic of the output voltage Vm at the normal temperature Tc_nml (the response characteristic indicated by the curve k1 in FIG. 6). ) To adjust the proportional gain Kp1 and the integral gain Ki1.

  PI controller 523 receives deviation ΔVdc from subtractor 521, and receives proportional gain Kp 1 and integral gain Ki 1 from gain correction unit 522. PI controller 523 calculates feedback voltage command Vdc_com_fb by substituting deviation ΔVdc, proportional gain Kp1 and integral gain Ki1 into the following equation, and outputs the calculated feedback voltage command Vdc_com_fb to duty ratio conversion unit 54.

Vdc_com_fb = Kp1 × ΔVdc + Ki1 × ΣΔVdc (3)
Duty ratio converter 54 includes a converter duty ratio calculator 541 and a converter PWM signal converter 542. Converter duty-ratio calculation unit 541 sets output voltage Vm from voltage sensor 13A to feedback voltage command Vdc_com_fb based on voltage Vb from voltage sensor 10 and feedback voltage command Vdc_com_fb from PI controller 523. To calculate the duty ratio. Converter PWM signal converter 542 generates a signal PWC for turning on / off NPN transistors Q1 and Q2 of boost converter 12 based on the duty ratio from converter duty ratio calculator 541. Then, converter PWM signal converter 542 outputs generated signal PWC to NPN transistors Q1 and Q2 of boost converter 12. Then, NPN transistors Q1, Q2 of boost converter 12 are turned on / off based on signal PWC. Thereby, boost converter 12 converts the DC voltage into output voltage Vm so that output voltage Vm matches voltage command Vdc_com.

  As described above, when the converter control means 302 of the control device 30 receives the temperature Tc of the capacitor C2 from the temperature sensor 13B, the converter control means 302 calculates the proportional gain Kp1 and the integral gain Ki1 in the feedback control of the output voltage Vm according to the temperature Tc of the capacitor C2. Using the adjusted proportional gain Kp1 and integral gain Ki1, the DC voltage Vb is adjusted so that the output voltage Vm of the boost converter 12 matches the voltage command Vdc_com calculated based on the torque command value TR1 (or TR2). The voltage conversion in the step-up converter 12 from the output voltage Vm to the output voltage Vm is feedback-controlled. Thus, boost converter 12 converts DC voltage Vb from DC power supply B into output voltage Vm so that output voltage Vm smoothly matches voltage command Vdc_com even if temperature Tc of capacitor C2 varies.

  FIG. 8 is a diagram illustrating the relationship between the capacitance and the temperature Tc in the electrolytic capacitor. FIG. 9 is a diagram showing the relationship between the capacitance of the film capacitor and the temperature Tc. Referring to FIGS. 8 and 9, the capacitance C decreases as the capacitor temperature Tc decreases. Therefore, when the capacitor temperature Tc is lower than the normal temperature Tc_nml, the capacitance C becomes smaller than the value at the normal temperature Tc_nml. Therefore, the proportional gain Kp1 and the integral gain Ki1 in the feedback control are changed to the proportional gain Kpo and the integral at the normal temperature Tc_nml. When the gain is kept at Kio, a high proportional gain and integral gain are apparently set, and feedback control of the output voltage Vm diverges. Further, when the capacitor temperature Tc rises above the room temperature Tc_nml, the capacitance C becomes larger than the value at the room temperature Tc_nml. Therefore, the proportional gain Kp1 and the integral gain Ki1 in the feedback control are changed to the proportional gain Kpo and the integral at the room temperature Tc_nml. When the gain is kept at Kio, a low proportional gain and integral gain are apparently set, and the output voltage Vm hardly reaches the voltage command Vdc_com.

  Therefore, in the present invention, when the capacitor temperature Tc is lower than the room temperature Tc_nml and the capacitance C is smaller than the value at the room temperature Tc_nml, the proportional gain Kp1 is obtained using the equations (1) and (2), respectively. And the integral gain Ki1 is made smaller than the proportional gain Kpo and integral gain Kio at room temperature Tc_nml, and the response characteristic of the output voltage Vm is the response characteristic of the output voltage Vm at room temperature Tc_nml (response characteristic shown by the curve k1 in FIG. 6). When the proportional gain and the integral gain are adjusted so as to be substantially the same, the capacitor temperature Tc rises above the room temperature Tc_nml, and the capacitance C becomes larger than the value at the room temperature Tc_nml, the equations (1) and (2 ) Is used to set the proportional gain Kp1 and the integral gain Ki1 to the proportional gain at room temperature Tc_nml. The proportional gain and the integral gain are set so that the response characteristic of the output voltage Vm is substantially the same as the response characteristic of the output voltage Vm at room temperature Tc_nml (the response characteristic indicated by the curve k1 in FIG. 6), which is larger than Kpo and the integral gain Kio. Will be adjusted.

  As a result, by correcting the proportional gain Kp1 and the integral gain Ki1 using the equations (1) and (2), respectively, even if the temperature Tc of the capacitor C2 fluctuates, the response characteristic of the output voltage Vm is output at the normal temperature Tc_nml. The response characteristic of the voltage Vm (response characteristic indicated by the curve k1 in FIG. 6) can be substantially matched, and feedback control can be performed so that the output voltage Vm smoothly matches the voltage command Vdc_com.

  As shown in FIG. 8, in the electrolytic capacitor, the rate at which the capacitance C decreases due to the decrease in temperature Tc is larger than that in the case of a film capacitor. For example, in the electrolytic capacitor, the capacitance C is about half of the value at room temperature Tc_nml below the freezing point.

  Therefore, in order to stabilize the feedback control of the output voltage Vm with respect to the temperature variation of the capacitor, the capacitance C with respect to the temperature change is used rather than using an electrolytic capacitor in which the capacitance C greatly varies with the temperature change. It is preferable to use a film capacitor having a small change rate.

  However, the electrolytic capacitor is characterized in that it is cheaper than the film capacitor and has a large capacitance C at room temperature Tc_nml. On the other hand, in order to drive the AC motor M1 stably even when the torque command value TR1 of the AC motor M1 used as an electric motor increases rapidly, it is necessary to increase the capacity of the capacitor C2.

  Therefore, an electrolytic capacitor that is low in cost and has a large capacitance C at room temperature Tc_nml is more suitable for practical use. The instability of the feedback control of the output voltage Vm generated by the change in the capacitance C of the electrolytic capacitor due to the temperature fluctuation is controlled by the control gain (proportional gain Kp1 and integral) of the feedback control according to the temperature Tc of the capacitor according to the present invention. It is eliminated by correcting the gain Ki1). As a result, the electrolytic capacitor is a capacitor capable of realizing cost reduction, stable driving of AC motor M1, and stabilization of feedback control of output voltage Vm.

  Therefore, in the present invention, an electrolytic capacitor is preferably used as the capacitor C2.

  FIG. 10 is a flowchart for explaining an operation of correcting the proportional gain Kp1 and the integral gain Ki1 in the feedback control of the output voltage Vm. Referring to FIG. 10, when a series of operations is started, gain correction unit 522 sets an initial control gain, that is, proportional gain Kpo and integral gain Kio at room temperature Tc_nml (step S1). The gain correction unit 522 receives the temperature Tc of the capacitor C2 from the temperature sensor 13B, and determines a correction coefficient Kc corresponding to the received temperature Tc using the curve k2 shown in FIG. 7 (step S2). After that, the gain correction unit 522 corrects the proportional gain Kpo and the integral gain Kio by multiplying the proportional gain Kpo and the integral gain Kio by the correction coefficient Kc, respectively, and determines the final proportional gain Kp1 and the integral gain Ki1 (step). S3). Thereby, a series of operation | movement is complete | finished.

  The proportional gain Kp1 and the integral gain Ki1 constitute a “control gain”.

  Further, the response characteristic of the output voltage Vm indicated by the curve k1 in FIG. 6 constitutes a “preferred response characteristic”.

  Further, the proportional gain Kpo and the integral gain Kio at room temperature Tc_nml constitute a “preferred control gain”.

  Further, the proportional gain Kpo constitutes a “preferred proportional gain”, and the integral gain Kio constitutes a “preferred integral gain”.

  Further, boost converter 12 constitutes a “voltage converter”, AC motor M1 or AC motor M2 constitutes a “load”, and inverter 14 or inverter 31 constitutes a “drive circuit” that drives the load. .

  Furthermore, converter control means 302 adjusts the control gain (proportional gain Kp1 and integral gain Ki1) when feedback controlling boost converter 12 so that output voltage Vm becomes voltage command Vdc_com according to temperature Tc of capacitor C2. Using the adjusted control gain, “control means” is configured to feedback control the boost converter 12 so that the output voltage Vm becomes the voltage command Vdc_com.

  Furthermore, voltage sensors 10 and 13A, boost converter 12, temperature sensor 13B, current sensors 24 and 28, and converter control means 302 constitute a “voltage converter”.

[Embodiment 2]
FIG. 11 is a schematic diagram of a motor drive device including the voltage conversion device according to the second embodiment. Referring to FIG. 11, motor drive device 100A provided with the voltage conversion device according to the second embodiment replaces voltage sensor 10 and control device 30 of motor drive device 100 shown in FIG. 1 with voltage sensor 10A and control device 30A, respectively. Instead, a temperature sensor 10B is added, and the rest is the same as the motor drive device 100.

  In motor drive device 100A, voltage sensor 10A detects DC voltage Vb output from DC power supply B, and outputs the detected DC voltage Vb to control device 30A.

  The temperature sensor 10B detects the temperature Tb of the DC power supply B, and outputs the detected temperature Tb to the control device 30A. The control device 30A, based on the temperature Tb of the DC power supply B from the temperature sensor 10B and the temperature Tc of the capacitor C2 from the temperature sensor 13B, uses a control gain (proportional gain) in feedback control of the output voltage Vm by a method described later. And the integration gain), and the boost converter 12 is feedback-controlled using the adjusted control gain so that the output voltage Vm matches the voltage command Vdc_com.

  The control device 30 </ b> A performs the same functions as the control device 30.

  FIG. 12 is a functional block diagram of control device 30A shown in FIG. Referring to FIG. 12, control device 30 </ b> A is the same as control device 30 except that converter control means 302 of control device 30 shown in FIG. 2 is replaced with converter control means 302 </ b> A.

  Converter control means 302A receives motor rotational speeds MRN1, 2 and torque command values TR1, 2 from an external ECU, receives voltage Vb from voltage sensor 10A, receives voltage Vm from voltage sensor 13A, and receives temperature Tb from temperature sensor 10B. The temperature Tc is received from the temperature sensor 13B.

  Converter control means 302A will be described later when AC motor M1 (or AC motor M2) is driven based on motor rotational speeds MRN1, 2 and torque command values TR1, 2, voltages Vb, Vm and temperatures Tb, Tc. By the method, a signal PWC for feedback controlling the boost converter 12 is generated so that the output voltage Vm matches the voltage command Vdc_com, and the generated signal PWC is output to the NPN transistors Q1 and Q2 of the boost converter 12.

  FIG. 13 is a functional block diagram of converter control means 302A shown in FIG. Referring to FIG. 13, converter control means 302A is obtained by replacing feedback voltage command calculation unit 52 of converter control means 302 shown in FIG. 4 with feedback voltage command calculation unit 52A. The same.

  Feedback voltage command calculation unit 52A receives output voltage Vm of boost converter 12 from voltage sensor 13A, receives temperature Tb of DC power supply B from temperature sensor 10B, receives temperature Tc of capacitor C2 from temperature sensor 13B, and receives inverter input voltage. A voltage command Vdc_com is received from command calculation unit 50. The feedback voltage command calculation unit 52A calculates a deviation ΔVdc between the voltage command Vdc_com and the voltage Vm, and sets a control gain when feedback control is performed so that the output voltage Vm matches the voltage command Vdc_com. Correction is made by a method described later according to Tb and the temperature Tc of the capacitor C2. Then, feedback voltage command calculation unit 52A calculates feedback voltage command Vdc_com_fb by the above-described method based on calculated deviation ΔVdc and the corrected control gain, and duty ratio conversion unit 54 calculates the calculated feedback voltage command Vdc_com_fb. Output to.

  FIG. 14 is a functional block diagram of feedback voltage command calculation unit 52A and duty ratio conversion unit 54 shown in FIG. Referring to FIG. 14, feedback voltage command calculation unit 52A is obtained by replacing gain correction unit 522 of feedback voltage command calculation unit 52 shown in FIG. 5 with gain correction unit 522A, and the other is a feedback voltage command calculation unit. 52.

  The gain correction unit 522A controls the control gain when the temperature Tb of the DC power supply B and the temperature Tc of the capacitor C2 are normal temperatures, that is, the proportional gain Kpo when the temperature Tb of the DC power supply B and the temperature Tc of the capacitor C2 are normal temperatures. And the integral gain Kio, and receives the temperature Tb of the DC power source B from the temperature sensor 10B and the temperature Tc of the capacitor C2 from the temperature sensor 13B.

  Then, the gain correction unit 522A corrects the proportional gain Kpo and the integral gain Kio according to the temperatures Tb and Tc, and outputs the corrected proportional gain Kp2 and integral gain Ki2 to the PI controller 523.

  FIG. 15 is a diagram showing the relationship between the correction coefficient Kb and the temperature Tb of the DC power supply B. The correction coefficient Kb is a correction coefficient for correcting the proportional gain Kpo and the integral gain Kio at normal temperature according to the temperature Tb of the DC power supply B.

  Referring to FIG. 15, correction coefficient Kb changes according to curve k3 with respect to temperature Tb of DC power supply B. More specifically, the correction coefficient Kb increases as the temperature Tb of the DC power supply B decreases. When the temperature Tb of the DC power supply B is the normal temperature Tc_nml, the correction coefficient Kb is “1”. The correction coefficient Kb when the temperature Tb of the DC power supply B is other than the room temperature Tc_nml is the response characteristic of the output voltage Vm at a temperature other than the room temperature Tc_nml, that is, the response characteristic of the output voltage Vm at the room temperature Tc_nml (ie, the curve in FIG. 6). This is a correction coefficient for correcting the proportional gain Kpo and the integral gain Kio so as to substantially match the response characteristic indicated by k1.

  Referring to FIG. 14 again, gain correction unit 522A holds curve k2 shown in FIG. 7 as a map showing the relationship between correction coefficient Kc and temperature Tc, and curve k3 shown in FIG. 15 is corrected coefficient Kb and temperature. When a temperature Tb of the DC power source B and a temperature Tc of the capacitor C2 are received from the temperature sensors 10B and 13B, respectively, a correction coefficient Kc corresponding to the received temperature Tc is displayed on a map ( The correction coefficient Kb corresponding to the received temperature Tb is extracted with reference to the curve (curve k3 shown in FIG. 15) extracted with reference to the curve k2) shown in FIG. 7, and the extracted correction coefficients Kb and Kc are extracted. Is multiplied by the proportional gain Kpo and the integral gain Kio, respectively, to obtain the proportional gain Kp2 and the integral gain used for feedback control of the output voltage Vm. To determine the i2. That is, the gain correction unit 522A determines the proportional gain Kp2 and the integral gain Ki2 by the following equations (4) and (5), respectively.

Kp2 = Kb × Kc × Kpo (4)
Ki2 = Kb × Kc × Kio (5)
As described above, the gain correction unit 522A multiplies the correction coefficient Kb determined according to the temperature Tb of the DC power supply B by the correction coefficient Kc determined according to the temperature Tc of the capacitor C2 to thereby adjust the DC power supply B. The proportional gain Kpo and the integral gain Kio when the temperature Tb and the temperature Tc of the capacitor C2 are normal temperature Tc_nml are corrected.

  The correction coefficient Kc decreases as the temperature Tc of the capacitor C2 decreases as shown in FIG. 7, and the correction coefficient Kb increases as the temperature Tb of the DC power source B decreases as shown in FIG. The gain correction unit 522A sets the proportional gain Kp2 and the integral gain Ki2 to be low as the temperature Tc of the capacitor C2 decreases when the temperature Tc of the capacitor C2 decreases, and the DC correction when the temperature Tb of the DC power supply B decreases. As the temperature Tb of the power supply B decreases, the proportional gain Kp2 and the integral gain Ki2 are set higher. That is, the gain correction unit 522A adjusts the proportional gain and the integral gain in accordance with the temperature Tb of the DC power supply B and the temperature Tc of the capacitor C2.

  When motor drive device 100A is mounted on a hybrid vehicle or an electric vehicle, DC power supply B and capacitor C2 may be arranged at different positions. Therefore, the temperature Tb of the DC power supply B is not necessarily the same as the temperature Tc of the capacitor C2, and one of the temperature Tb of the DC power supply B and the temperature Tc of the capacitor C2 is the normal temperature Tc_nml, and the other is the normal temperature Tc_nml. It is also assumed that it is lower than that. Therefore, the gain correction unit 522A adjusts the proportional gain and the integral gain in accordance with the temperature Tb of the DC power supply B and the temperature Tc of the capacitor C2.

  In more detail, the gain correction unit 522A adjusts the proportional gain and the integral gain as follows.

  When the temperature Tb of the DC power supply B is normal temperature Tc_nml, the gain correction unit 522A adjusts the proportional gain and the integral gain according to the temperature Tc of the capacitor C2, as described in the first embodiment.

  Further, when the temperature Tc of the capacitor C2 is the normal temperature Tc_nml, the gain correction unit 522A adjusts the proportional gain and the integral gain as follows according to the temperature Tb of the DC power supply B.

  As described above, since the correction coefficient Kb is “1” when the temperature Tb of the DC power supply B is the room temperature Tc_nml, the gain correction unit 522A uses the proportional gain Kpo and the integral gain Kio at the room temperature Tc_nml as the proportional gain. It outputs to PI controller 523 as Kp2 and integral gain Ki2. That is, when the temperature Tb of the DC power supply B is normal temperature Tc_nml, the gain correction unit 522A determines the proportional gain Kpo and integral that are determined in advance so that the output voltage Vm smoothly matches the voltage command Vdc_com according to the curve k1 in FIG. The gain Kio is output to the PI controller 523.

  When the temperature Tb of the DC power source B is lower than the normal temperature Tc_nml, the correction coefficient Kb increases with the decrease in the temperature Tb. Therefore, the gain correction unit 522A The proportional gain Kp2 and the integral gain Ki2 that are larger than the proportional gain Kpo and the integral gain Kio are respectively output to the PI controller 523.

  Further, when the temperature Tb of the DC power supply B becomes higher than the normal temperature Tc_nml, the correction coefficient Kb decreases as the temperature Tb increases. Therefore, the gain correction unit 522A operates at the normal temperature Tc_nml as the temperature Tb increases. The proportional gain Kp2 and the integral gain Ki2 that are smaller than the proportional gain Kpo and the integral gain Kio are respectively output to the PI controller 523.

  As described above, the correction coefficient Kb when the temperature Tb of the DC power supply B is other than the room temperature Tc_nml is the response characteristic of the output voltage Vm at a temperature other than the room temperature Tc_nml. FIG. 6 is a correction coefficient for correcting the proportional gain Kpo and the integral gain Kio so as to substantially match the response characteristic indicated by the curve k1 in FIG.

  Therefore, when the temperature Tc of the capacitor C2 is normal temperature Tc_nml and the temperature Tb of the DC power source B deviates from the normal temperature Tc_nml, the gain correction unit 522A determines that the response characteristic of the output voltage Vm at each temperature is the output voltage Vm at normal temperature Tc_nml. The proportional gain Kp2 and the integral gain Ki2 are adjusted so as to substantially match the response characteristics (response characteristics indicated by the curve k1 in FIG. 6).

  Further, when the temperature Tb of the DC power supply B and the temperature Tc of the capacitor C2 change simultaneously, the gain correction unit 522A adjusts the proportional gain Kp2 and the integral gain Ki2 based on the multiplication result of the correction coefficient Kb and the correction coefficient Kc. That is, when the temperature Tb of the DC power supply B and the temperature Tc of the capacitor C2 change simultaneously, the gain correction unit 522A adjusts the proportional gain Kp2 and the integral gain Ki2 so as to increase as the temperature Tb of the DC power supply B decreases. Then, the proportional gain Kp2 and the integral gain Ki2 are adjusted so as to decrease as the temperature Tc of the capacitor C2 decreases.

  In the second embodiment, PI controller 523 substitutes deviation ΔVdc from subtractor 521 and proportional gain Kp2 and integral gain Ki2 from gain correction unit 522A into equation (3) for feedback voltage command Vdc_com_fb. Is calculated.

  FIG. 16 is a diagram showing the relationship between the internal resistance and the temperature Tb in the DC power supply B. Referring to FIG. 16, the internal resistance increases as temperature Tb of DC power supply B decreases. Therefore, when the temperature Tb of the DC power supply B is lower than the normal temperature Tc_nml, the internal resistance becomes higher than the value at the normal temperature Tc_nml. Therefore, the proportional gain Kp2 and the integral gain Ki2 in the feedback control are changed to the proportional gain Kpo and the integral at the normal temperature Tc_nml. When the gain is kept at Kio, the low proportional gain and integral gain are apparently set, and the output voltage Vm hardly reaches the voltage command Vdc_com. Further, when the temperature Tb of the DC power supply B rises above the normal temperature Tc_nml, the internal resistance becomes lower than the value at the normal temperature Tc_nml, so that the proportional gain Kp2 and the integral gain Ki2 in the feedback control are changed to the proportional gain Kpo and the integral at the normal temperature Tc_nml. When the gain is kept at Kio, a high proportional gain and integral gain are apparently set, and feedback control of the output voltage Vm diverges.

  Therefore, in the present invention, when the temperature Tb of the DC power supply B is lower than the normal temperature Tc_nml and the internal resistance is higher than the value at the normal temperature Tc_nml, the proportional gain Kp2 is obtained using the equations (4) and (5), respectively. And the integral gain Ki2 is higher than the proportional gain Kpo and integral gain Kio at room temperature Tc_nml, and the response characteristic of the output voltage Vm is the response characteristic of the output voltage Vm at room temperature Tc_nml (response characteristic indicated by the curve k1 in FIG. 6). When the proportional gain and the integral gain are adjusted so as to be substantially the same, the temperature Tb of the DC power supply B rises above the normal temperature Tc_nml, and the internal resistance becomes lower than the value at the normal temperature Tc_nml, the equations (4) and (5) ) To set the proportional gain Kp2 and the integral gain Ki2 to the proportional gain Kpo at room temperature Tc_nml. The proportional gain and the integral gain are set so that the response characteristic of the output voltage Vm is substantially the same as the response characteristic of the output voltage Vm at room temperature Tc_nml (the response characteristic indicated by the curve k1 in FIG. 6). I decided to adjust it.

  As a result, by correcting the proportional gain Kp2 and the integral gain Ki2 using equations (4) and (5), respectively, even if the temperature Tb of the DC power supply B and the temperature Tc of the capacitor C2 vary, the output voltage Vm The response characteristic can be made to substantially match the response characteristic of the output voltage Vm at normal temperature Tc_nml (the response characteristic indicated by the curve k1 in FIG. 6), and feedback control can be performed so that the output voltage Vm smoothly matches the voltage command Vdc_com.

  FIG. 17 is another flowchart for explaining an operation of correcting the proportional gain Kp2 and the integral gain Ki2 in the feedback control of the output voltage Vm. Referring to FIG. 17, when a series of operations is started, gain correction unit 522A sets an initial control gain, that is, proportional gain Kpo and integral gain Kio at room temperature Tc_nml (step S11). Gain correction unit 522A receives temperature Tb of DC power supply B from temperature sensor 10B, and receives temperature Tc of capacitor C2 from temperature sensor 13B. Then, gain correction unit 522A determines a correction coefficient Kc corresponding to the received temperature Tc of capacitor C2 using curve k2 shown in FIG. 7 (step S12), and according to the received temperature Tb of DC power supply B. The correction coefficient Kb is determined using the curve k3 shown in FIG. 15 (step S13). Thereafter, the gain correction unit 522A corrects the proportional gain Kpo and the integral gain Kio by multiplying the proportional gain Kpo and the integral gain Kio by the correction coefficients Kb and Kc, respectively, and determines the final proportional gain Kp2 and the integral gain Ki2. (Step S14). Thereby, a series of operation | movement is complete | finished.

  The proportional gain Kp2 and the integral gain Ki2 constitute a “control gain”.

  Further, converter control means 302A uses control gain (proportional gain Kp2 and integral gain Ki2) for feedback control of boost converter 12 so that output voltage Vm becomes voltage command Vdc_com as a function of temperature Tb of DC power supply B and capacitor C2. The “control means” is configured to perform feedback control of the boost converter 12 so that the output voltage Vm matches the voltage command Vdc_com using the adjusted control gain.

  Furthermore, voltage sensors 10A and 13A, boost converter 12, temperature sensors 10B and 13B, current sensors 24 and 28, and converter control means 302A constitute a “voltage converter”.

  Others are the same as in the first embodiment.

  In the present invention, “normal temperature” refers to the most stable temperature among the temperatures that the motor drive devices 100 and 100A can take. Then, at the most stable temperature, the proportional gain Kpo and the integral gain Kio are determined in advance so that the response characteristic of the output voltage Vm becomes the curve k1 shown in FIG. 6, and the determined proportional gain Kpo and integral gain Kio are gained. The correction unit 522, 522A holds.

  By doing so, feedback control of the output voltage Vm can be stably performed regardless of how the usage environment of the hybrid vehicle or electric vehicle on which the motor drive devices 100 and 100A are mounted changes.

  That is, the most stable temperature in each use environment is extracted, and the proportional gain Kpo and the integral gain Kio are determined in advance so that the response characteristic of the output voltage Vm becomes the curve k1 shown in FIG. 6 at the extracted most stable temperature. By doing so, the feedback control of the output voltage Vm can be performed stably even if the operating temperature of the motor drive devices 100 and 100A deviates from the most stable temperature.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and is intended to include meanings equivalent to the scope of claims for patent and all modifications within the scope.

  The present invention is applied to a voltage converter capable of stable feedback control even when the temperature fluctuates.

It is the schematic of the motor drive device provided with the voltage converter by Embodiment 1 of this invention. It is a functional block diagram of the control apparatus shown in FIG. It is a functional block diagram of the inverter control means shown in FIG. It is a functional block diagram of the converter control means shown in FIG. FIG. 5 is a functional block diagram of a feedback voltage command calculation unit and a duty ratio conversion unit shown in FIG. 4. It is a timing chart of output voltage Vm. It is a figure which shows the relationship between a correction coefficient and the temperature of a capacitor | condenser. It is a figure which shows the relationship between the electrostatic capacitance in an electrolytic capacitor, and temperature Tc. It is a figure which shows the relationship between the electrostatic capacitance in a film capacitor, and temperature Tc. It is a flowchart for demonstrating the operation | movement which correct | amends the proportional gain and integral gain in feedback control of an output voltage. It is the schematic of the motor drive device provided with the voltage converter by Embodiment 2. It is a functional block diagram of the control apparatus shown in FIG. It is a functional block diagram of the converter control means shown in FIG. FIG. 14 is a functional block diagram of a feedback voltage command calculation unit and a duty ratio conversion unit shown in FIG. 13. It is a figure which shows the relationship between a correction coefficient and the temperature of DC power supply. It is a figure which shows the relationship between internal resistance in DC power supply, and temperature. 10 is another flowchart for explaining an operation of correcting the proportional gain and the integral gain in the feedback control of the output voltage.

Explanation of symbols

  10, 10A, 13A voltage sensor, 10B, 13B temperature sensor, 12 step-up converter, 14, 31 inverter, 15 U-phase arm, 16 V-phase arm, 17 W-phase arm, 24, 28 current sensor, 30, 30A control device, 40 motor control phase voltage calculation unit, 42 inverter PWM signal conversion unit, 50 inverter input voltage command calculation unit, 52, 52A feedback voltage command calculation unit, 54 duty ratio conversion unit, 100, 100A motor drive device, 301 inverter control Means, 302, 302A converter control means, 521 subtractor, 522, 522A gain correction section, 523 PI controller, 541 converter duty ratio calculation section, 542 converter PWM signal conversion section, B DC power supply, SR1, SR2 system relay , C1, C2 capacitor, Q1 to Q8 NPN transistor, D1 to D8 diode, L1 reactor, M1, M2 AC motor.

Claims (15)

A voltage converter that converts a DC voltage from a DC power source into the output voltage so that the output voltage matches the command voltage,
A capacitive element provided on the input side of the drive circuit for driving the load;
A voltage converter that converts a DC voltage from the DC power source into the output voltage and outputs the converted voltage to the capacitive element;
A control gain when performing feedback control of the voltage converter so that the output voltage matches the command voltage is adjusted according to the temperature of the capacitive element, and the output voltage is adjusted using the adjusted control gain. And a control means for feedback-controlling the voltage converter so as to match the voltage.   The voltage conversion apparatus according to claim 1, wherein the control unit adjusts the control gain so that the control gain decreases as the temperature of the capacitive element decreases.   The voltage conversion apparatus according to claim 1, wherein the control unit adjusts the control gain so that a response characteristic of the output voltage with respect to a temperature variation of the capacitive element is substantially the same as a suitable response characteristic.   The voltage converter according to claim 3, wherein the suitable response characteristic is a response characteristic of the output voltage when the temperature of the capacitive element is normal temperature.   When the control gain set when the temperature of the capacitive element is normal temperature is set to a suitable control gain, the control means is configured so that the response characteristic of the output voltage is substantially the same as the suitable response characteristic. The voltage converter according to claim 4, wherein the control gain is adjusted by multiplying the suitable control gain by a correction coefficient determined in accordance with a temperature of the capacitive element.   The control means holds a map indicating a relationship between the temperature of the capacitive element and the correction coefficient, extracts a correction coefficient corresponding to the temperature of the capacitive element with reference to the map, and extracts the correction The voltage conversion apparatus according to claim 5, wherein the control gain is adjusted by multiplying the suitable control gain by a coefficient. The suitable control gain comprises a suitable proportional gain and a suitable integral gain,
The voltage converter according to claim 5, wherein the control unit adjusts the control gain by multiplying both the preferable proportional gain and the preferable integral gain by the correction coefficient. A voltage converter for converting a DC voltage from a DC power source into the output voltage so that the output voltage matches the command voltage,
A capacitive element provided on the input side of the drive circuit for driving the load;
A voltage converter that converts a DC voltage from the DC power source into the output voltage and outputs the output voltage to the capacitive element;
A control gain when feedback controlling the voltage converter so that the output voltage matches the command voltage is adjusted according to the temperature of the capacitive element and the temperature of the DC power supply, and the adjusted control gain is used. A voltage converter comprising: control means for feedback-controlling the voltage converter so that the output voltage matches the command voltage.   The control means adjusts the control gain so as to decrease as the temperature of the capacitive element decreases, and adjusts the control gain so as to increase as the temperature of the DC power supply decreases. The voltage converter described in 1.   The voltage according to claim 8, wherein the control means adjusts the control gain so that a response characteristic of the output voltage with respect to a temperature variation of the capacitive element and the DC power supply is substantially the same as a suitable response characteristic. Conversion device.   The voltage conversion device according to claim 10, wherein the suitable response characteristic is a response characteristic of the output voltage when the temperature of the capacitive element and the DC power supply is normal temperature.   When the control means has a control gain set when the temperature of the capacitive element and the DC power supply is normal temperature, the response characteristic of the output voltage is substantially the same as the preferable response characteristic. The control gain is adjusted by multiplying the suitable control gain by first and second correction coefficients determined according to the temperature of the capacitive element and the temperature of the DC power supply, respectively. The voltage converter described in 1.   The control means includes a first map indicating a relationship between the temperature of the capacitive element and the first correction coefficient, and a second map indicating a relationship between the temperature of the DC power supply and the second correction coefficient. A first correction coefficient corresponding to the temperature of the capacitive element and a second correction coefficient corresponding to the temperature of the DC power supply are extracted with reference to the first and second maps, respectively, The voltage conversion apparatus according to claim 12, wherein the control gain is adjusted by multiplying the suitable first and second correction coefficients by the suitable control gain. The suitable control gain comprises a suitable proportional gain and a suitable integral gain,
14. The control unit according to claim 12 or 13, wherein the control unit adjusts the control gain by multiplying both the suitable proportional gain and the suitable integral gain by the first and second correction factors. Voltage converter.   The voltage converter according to any one of claims 1 to 14, wherein the capacitive element is an electrolytic capacitor.

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