JP2011091952A - Power supply system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent damage on the components of a secondary battery during temperature rise control thereof in a power supply system equipped with a voltage converter which converts the output voltage of the secondary battery. <P>SOLUTION: A controller 30 performs temperature rise control for increasing the amplitude of a ripple current passing through the secondary battery BAT by operating a converter 12 at a switching frequency lower than normal one when the temperature of the secondary battery BAT is low. The switching frequency during temperature rise control is predetermined according to the frequency characteristics of the internal impedance 5 of the secondary battery BAT. Inductance of the reactor L1 in the converter 12 is determined so that the predicted value of the amplitude of a ripple current does not exceed the maximum allowable current of IGBT elements Q1 and Q2 during temperature rise control. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a power supply system, and more particularly to a power supply system including a voltage converter as a reactor component.

  As one of power converters, a converter including a chopper circuit that converts a DC voltage using a reactor is used (see, for example, Patent Documents 1 and 2). In such a chopper circuit, since the switched voltage is applied to the reactor, the current flowing through the reactor (hereinafter also referred to as the reactor current) undergoes a temporal change in the slope according to the inductance of the reactor. That is, an AC current (hereinafter also referred to as a ripple current) that depends on the switching frequency of the power semiconductor element constituting the converter is superimposed on the reactor current. This ripple current increases as the inductance of the reactor decreases.

  In Patent Documents 1 and 2, a converter (chopper circuit) configured to convert the output voltage of the secondary battery is used, and in a low temperature region where the internal resistance of the secondary battery is increased, the secondary battery is described. It is described that the temperature is raised. Specifically, it is described that the temperature of the secondary battery is raised by increasing the amount of heat generated by the secondary battery by increasing the ripple current by changing the carrier frequency used for on / off control of the power switching element. Yes.

JP 2006-6073 A Japanese Patent No. 3732828

  However, if the ripple current is increased during the temperature rise control of the secondary battery, the instantaneous value of the current flowing through the converter also increases, and there is a concern that the component parts may be damaged by the passage of an excessive current.

  The present invention has been made to solve such problems. An object of the present invention is to increase the secondary battery in a power supply system including a voltage converter for converting the output voltage of the secondary battery. This is to prevent damage to the components during temperature control.

  A power supply system according to the present invention includes a secondary battery, a voltage converter that converts a DC voltage from the secondary battery, and a control device that controls the voltage converter. The voltage converter includes a power switching element that is on / off controlled in a cycle according to the carrier frequency, and a reactor connected in series with the switching element with respect to the secondary battery. The control device includes a determination unit that determines whether or not the temperature increase control of the secondary battery is necessary, and a frequency adjustment unit. When it is determined that the temperature raising control is necessary, the frequency adjustment unit sets the carrier frequency to the first frequency set in advance according to the frequency characteristic of the internal impedance of the secondary battery, while the temperature raising control is performed. When determined to be necessary, the carrier frequency is configured to be set to a second frequency higher than the first frequency. The internal impedance at the first frequency is lower than the internal impedance at the second frequency. The inductance value of the reactor is determined so that the amplitude of the ripple component of the current flowing through the reactor when the carrier frequency is the first frequency does not exceed the maximum allowable current of the component on the current path.

  Preferably, in the voltage converter, the reactor is electrically connected between the positive electrode of the secondary battery and the first node, and the power switching element is connected to the power supply wiring to which the capacitor is connected and the first node. A first switching element electrically connected to the node, a ground wiring connected to the negative electrode of the secondary battery, and a second switching element electrically connected to the first node Have The control device includes a duty ratio control unit that generates a signal for complementarily turning on and off the first and second switching elements in accordance with the duty ratio command value.

  More preferably, the control device further includes a voltage command calculation unit. The voltage command calculation unit fixes the duty ratio command value to a predetermined value when the temperature increase control is executed, while the duty ratio command value is set so that the voltage of the power supply wiring matches the voltage command value when the temperature increase control is not executed. Configured to adjust.

  Preferably, the first frequency is determined in correspondence with a frequency at which the internal impedance is minimized.

  Preferably, the inductance of the reactor is set such that the amplitude value of the ripple component of the current flowing through the reactor when the carrier frequency is the first frequency does not exceed the maximum allowable current of the power switching element.

  According to the present invention, in the power supply system including the voltage converter that converts the output voltage of the secondary battery, it is possible to prevent damage to the components during the temperature rise control of the secondary battery.

1 is a schematic block diagram of a motor drive device to which a power supply system according to an embodiment of the present invention is applied. It is a functional block diagram of the control apparatus shown in FIG. It is a wave form diagram explaining operation | movement of the duty ratio control part shown in FIG. It is an example of the equivalent circuit schematic of the internal impedance of a secondary battery. It is a conceptual diagram which shows the frequency characteristic of the internal impedance of a secondary battery. It is a conceptual diagram of the ripple current contained in an inductor current. It is a conceptual diagram which shows the waveform of the reactor current at the time of temperature rising control of a secondary battery. It is a wave form diagram explaining the relationship between a carrier frequency and a reactor current. It is a wave form diagram which shows the reactor current in the power supply system by embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same reference numerals indicate the same or corresponding parts.

  FIG. 1 is a schematic block diagram of a motor drive device to which a power supply system according to an embodiment of the present invention is applied.

  Referring to FIG. 1, motor drive device 100 includes secondary battery BAT, battery sensor 10, voltage sensors 11 and 13, current sensor 24, system relays SR1 and SR2, capacitors C1 and C2, and a converter. 12, an inverter 14, and a control device 30. In particular, the “power supply system” is configured by the secondary battery BAT, the converter 12, and the part related to the converter control in the control device 30.

  AC motor M1 is a drive motor for generating torque for driving drive wheels of an electric vehicle such as a hybrid vehicle, an electric vehicle, or a fuel cell vehicle. Alternatively, this motor has the function of a generator driven by an engine, and operates as an electric motor for the engine, for example, can be incorporated into a hybrid vehicle so that the engine can be started. Also good.

  Current sensor 24 detects motor current MCRT flowing through AC motor M1 and outputs the detected motor current MCRT to control device 30. Since the sum of the instantaneous values of the three-phase currents is zero, it is possible to calculate the current of the phase in which the current sensor 24 is not arranged by assuming that the current sensor 24 is arranged in only two phases. is there.

  The secondary battery BAT is made of, for example, a nickel metal hydride battery or a lithium ion battery. As is well known, the secondary battery BAT has an internal impedance 5. The battery sensor 10 measures the state value of the secondary battery BAT. The battery sensor 10 comprehensively evaluates a sensor group provided in the secondary battery BAT, and includes at least a voltage sensor, a current sensor, and a temperature sensor. Output voltage Vb, input / output current Ib (also referred to as battery current Ib) and temperature Tb (also referred to as battery temperature Tb) of secondary battery BAT detected by battery sensor 10 are output to control device 30. System relays SR1 and SR2 are turned on / off by a signal SE from control device 30.

  Converter 12 includes a reactor L1, IGBTs (Insulated Gate Bipolar Transistor) elements Q1, Q2, and diodes D1, D2. In the present embodiment, the IGBT element is described as a representative example of a power switching element (hereinafter simply referred to as “switching element”).

  One end of reactor L1 is electrically connected to the positive electrode of secondary battery BAT via system relay SR1. Reactor L1 has the other end connected to node N1 corresponding to an intermediate point between IGBT element Q1 and IGBT element Q2.

  IGBT elements Q1, Q2 are connected in series between power supply line PL and ground line GL via node N1. The collector of IGBT element Q1 is connected to power supply line PL, and the emitter of IGBT element Q2 is connected to ground line GL. A smoothing capacitor C2 is connected to the power supply wiring PL. The ground wiring GL is electrically connected to the negative electrode of the secondary battery BAT via the system relay SR2. Antiparallel diodes D1 and D2 are connected between the collectors and emitters of IGBT elements 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 power supply line PL and ground line GL.

  U-phase arm 15 includes IGBT elements Q3 and Q4 connected in series, V-phase arm 16 includes IGBT elements Q5 and Q6 connected in series, and W-phase arm 17 includes IGBT elements Q7 and Q7 connected in series. Consists of Q8. Antiparallel diodes D3 to D8 are connected between the collectors and emitters of the IGBT elements 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. That is, 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 IGBT element Q3. The other end of the V-phase coil is connected to the intermediate point of IGBT elements Q5 and Q6, and the other end of the W-phase coil is connected to the intermediate point of IGBT elements Q7 and Q8, respectively.

  Capacitor C1 smoothes DC voltage Vb supplied from secondary battery BAT. Voltage sensor 11 detects the voltage across capacitor C 1, that is, input voltage Vl of converter 12, and outputs the detected DC voltage Vl to control device 30.

  Converter 12 performs bidirectional DC voltage conversion between DC voltage Vl supplied from secondary battery BAT to capacitor C1 and DC voltage Vm of power supply line PL. More specifically, converter 12 controls the DC voltage of power supply line PL by performing on / off control of IGBT elements Q1, Q2 in accordance with signal PWD from control device 30. Basically, converter 12 is controlled such that IGBT elements Q1 and Q2 are complementarily and alternately turned on and off within each switching period.

  The voltage conversion ratio (Vm / Vl) in the DC voltage conversion is controlled by the ON period ratio (duty ratio) of the IGBT elements Q1 and Q2 with respect to the switching period. If IGBT elements Q1 and Q2 are fixed on and off, respectively, Vm = Vl (voltage conversion ratio = 1.0) can be obtained.

  Capacitor C2 smoothes the DC voltage on power supply line PL output from converter 12, that is, the DC side voltage of inverter 14. The voltage sensor 13 detects the voltage across the capacitor C2, that is, the output voltage Vm of the converter 12 (corresponding to the input voltage to the inverter 14, the same applies hereinafter), and outputs the detected output voltage Vm to the control device 30. Output.

  Inverter 14 converts the DC voltage on power supply line PL into an AC voltage based on signal PWMI from control device 30, and drives AC motor M1. As a result, AC motor M1 is driven so as to generate torque specified by torque command value TR.

  Further, during regenerative braking of the electric vehicle equipped with the motor drive device 100, the signal PWMI from the control device 30 is generated so that the inverter 14 converts the AC voltage generated by the AC motor M1 into a DC voltage. The DC voltage converted by the inverter 14 is supplied to the secondary battery BAT through the capacitor C2 and the converter 12. That is, the secondary battery BAT can be charged with regenerative power.

  The regenerative braking here refers to braking with regenerative power generation when the driver operating the electric vehicle performs a footbrake operation, or regenerative braking by turning off the accelerator pedal while driving, although the footbrake is not operated. This includes decelerating (or stopping acceleration) the vehicle while generating electricity.

  The control device 30 is composed of an electronic control unit (ECU), and performs software processing by executing a program stored in advance by a CPU (Central Processing Unit) (not shown) and / or hardware by a dedicated electronic circuit. By the processing, the operation of the motor driving device 100 is controlled.

  As a representative function, control device 30 is based on torque command value TR and motor rotational speed MRN, DC voltage Vl from voltage sensor 11, output voltage Vm from voltage sensor 13, and motor current MCRT from current sensor 24. Thus, a signal PWD for driving converter 12 and a signal PWMI for driving inverter 14 are generated, and the generated signal PWD and signal PWMI are output to converter 12 and inverter 14, respectively.

Signal PWD is a signal for controlling DC voltage conversion by converter 12, and specifically, is a signal for controlling on / off of IGBT elements Q1, Q2. Control device 30 generates signal PWD so that output voltage Vm of converter 12 matches voltage command value Vdccom.
Is generated. A method for generating the signal PWD will be described later. Control device 30 also adjusts the carrier frequency used for on / off control of IGBT elements Q 1, Q 2 of converter 12. A method for adjusting the carrier frequency will be described later.

  The signal PWMI is a signal for controlling DC / AC voltage conversion by the inverter 14, and is specifically a signal for controlling on / off of the IGBT elements Q3 to Q8. Control device 30 generates signal PWMI so that the output torque of AC motor M1 matches torque command value TR. When the torque command value TR is positive, the driving force of the electric vehicle can be generated by the AC motor M1.

  Torque command value TR is set to a negative value when the electric vehicle enters the regenerative braking mode. At this time, the control device 30 generates the signal PWMI so that the regenerative power (AC voltage) generated by the generation of the negative torque by the AC motor M1 is converted into a DC voltage. The DC voltage converted by the inverter 14 is stepped down by the converter 12 according to the signal PWD from the control device 30 and used for charging the secondary battery BAT.

  Furthermore, control device 30 generates signal SE for turning on / off system relays SR1, SR2 in accordance with the start / stop command of motor drive device 100, 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. Each functional block shown in FIG. 2 may be configured by an electronic circuit (hardware) having a function corresponding to the block, or realized by an ECU executing software processing according to a preset program. May be.

  Referring to FIG. 2, control device 30 includes a motor control phase voltage calculation unit 40, an inverter PWM signal conversion unit 42, an inverter input voltage command calculation unit 50, a feedback voltage command calculation unit 52, a duty ratio. A control unit 54, a determination unit 56, and a frequency adjustment unit 57 are included.

  Motor control phase voltage calculation unit 40 receives output voltage Vm of converter 12, that is, an input voltage to inverter 14 from voltage sensor 13, and receives motor current MCRT flowing in each phase of AC motor M <b> 1 from current sensor 24, Torque command value TR is received from an external ECU. The motor control phase voltage calculation unit 40 calculates the voltage to be applied to the coils of each phase of the AC motor M1 based on these input signals, and the calculated result is the inverter PWM signal conversion unit 42. To supply.

  Based on the calculation result received from the motor control phase voltage calculation unit 40, the inverter PWM signal conversion unit 42 generates a signal PWMI that actually turns on and off the IGBT elements Q3 to Q8 of the inverter 14, and the generated signal PWMI is output to each IGBT element Q3-Q8 of inverter 14.

  The IGBT elements Q3 to Q8 are subjected to switching control according to the signal PWMI, so that the current flowing through each phase of the AC motor M1 is controlled so that the AC motor M1 outputs the commanded torque. Thus, by controlling the motor drive current, a motor torque corresponding to the torque command value TR is output.

  On the other hand, inverter input voltage command calculation unit 50 calculates an optimum value (target value) of the inverter input voltage, that is, voltage command value Vdccom of converter 12 based on torque command value TR and motor rotation speed MRN. The calculated voltage command value Vdccom is output to feedback voltage command calculation unit 52.

  The feedback voltage command calculation unit 52 performs feedback based on the DC voltage Vl from the voltage sensor 11, the output voltage Vm of the converter 12 from the voltage sensor 13, and the voltage command value Vdccom from the inverter input voltage command calculation unit 50. The voltage command Vcn is calculated. The calculated feedback voltage command Vcn is output to the duty ratio control unit 54. This feedback voltage command Vcn corresponds to a “duty ratio command value” for matching the output voltage Vm to the voltage command value Vdccom.

  Referring to FIG. 3, duty ratio control unit 54 generates signal PWD based on voltage comparison between feedback voltage command Vcn from feedback voltage command calculation unit 52 and carrier wave CW. The period Tc of the carrier wave CW, that is, the carrier frequency is adjusted as described later by the frequency adjusting unit 57 in FIG.

  In the example of FIG. 3, the lower arm IGBT element Q <b> 2 is turned on while the upper arm switching element Q <b> 1 is turned off in a period in which the feedback voltage command Vcn is higher than the carrier wave CW having a fixed period Tc. . On the contrary, in a period in which the feedback voltage command Vcn is lower than the carrier wave CW, the upper arm IGBT element Q1 is turned on, while the lower arm switching element Q2 is turned off.

  In converter 12, if the on-duty of IGBT element Q2 in the lower arm is increased, the power storage in reactor L1 increases, and output voltage Vm increases. On the other hand, increasing the on-duty of the upper arm IGBT element Q1 reduces the output voltage Vm. Therefore, by controlling the duty ratio of IGBT elements Q1, Q2 by feedback voltage command Vcn, DC voltage Vm of power supply wiring PL is equal to or higher than the output voltage of secondary battery BAT according to voltage command value Vdccom. The voltage can be controlled.

  Referring to FIG. 2 again, signal PWD generated by duty ratio control unit 54 is a drive circuit (not shown) for driving control electrodes (gates) of IGBT elements Q1 and Q2 provided in converter 12. Is output).

  The determination unit 56 determines whether or not the temperature increase control of the secondary battery BAT is necessary based on the output of the battery sensor 10, typically the battery temperature Tb. In general, the secondary battery BAT has a characteristic that the internal resistance increases in a low temperature region. Therefore, in such a low temperature region, it is difficult to secure the output voltage and input / output power of the secondary battery BAT, and internal loss is also caused. The increase also decreases efficiency. Therefore, immediately after the start of operation of the electric vehicle in the severe cold season, it is necessary to quickly raise the temperature of the secondary battery BAT to reduce the internal resistance.

  Therefore, for example, determination unit 56 turns on request flag Fwu to request temperature increase control when battery temperature Tb is lower than predetermined determination temperature Tth, while temperature increase control is not required when Tb ≧ Tth. It is determined that there is, and the request flag Fwu is turned off. In general, the temperature characteristic of the internal resistance varies depending on the type of the battery, etc., so that the determination temperature Tth depends on the temperature characteristic of the secondary battery BAT (internal resistance value or rate of change of internal resistance with respect to temperature change) It can be set appropriately.

  The frequency adjustment unit 57 changes the carrier frequency fc (fc = 1 / Tc) according to the request flag Fwu. Specifically, at the time of temperature rise control of the secondary battery, the carrier frequency fc is set to a frequency fx lower than the normal frequency fo.

FIG. 4 shows an equivalent circuit diagram of the internal impedance of the secondary battery.
As shown in FIG. 4, the internal impedance 5 includes a resistance component representing a direct current resistance component such as a reaction resistance or an electric resistance of an electrolytic solution, an electric double layer formed at an interface of an active material, and a parallel circuit of a capacitor. Including. Further, in the high frequency region, an inductance component (not shown) cannot be ignored. For this reason, the magnitude | Z | of the internal impedance has a frequency characteristic as shown in FIG. A resistance component in the internal impedance corresponds to a so-called internal resistance.

  In the secondary battery BAT, when the battery current Ib passes through a resistance component in the internal impedance 5, internal heat generation due to Joule heat occurs. Since the Joule heat is proportional to the square of the passing current, heat for raising the temperature of the secondary battery BAT can be generated by the passage of the ripple current that is an alternating current. The amount of heat generated can be efficiently obtained by setting the frequency of the ripple current to the frequency fmin that minimizes the size of the internal impedance. As a result, in the secondary battery BAT, the internal impedance at the frequency fx is at least lower than the internal impedance at the frequency fo.

  FIG. 6 shows a reactor current waveform at the time of normal operation of converter 12, that is, when temperature increase control of the secondary battery is not executed.

  Referring to FIG. 6, reactor current IL rises during the on period of lower arm IGBT element Q2, while it repeats a decrease behavior during the on period of upper arm IGBT element Q1 at a constant period. A ripple current is generated. Since the carrier frequency fc = fo is normally set, a ripple current having a period To (frequency fo) is generated in the reactor current IL in accordance with the duty control shown in FIG. Thus, the reactor current IL has a mode in which the ripple current is superimposed on the DC current component. The product of the DC current component and the battery voltage Vb corresponds to the DC power input / output from the secondary battery BAT.

  The normal carrier frequency fo is designed in consideration of an audible frequency band so that electromagnetic noise is not easily detected by the user. As an example, fo is about 10 to 20 kHz.

  As shown in FIG. 7, during the temperature rise control of the secondary battery, the ripple current amplitude of the reactor current IL is increased by setting the carrier frequency to a frequency fx (fx = 1 / Tx) lower than the normal frequency. Since the reactor L1 and the secondary battery BAT are connected in series to the IGBT elements Q1 and Q2, the ripple current generated in the reactor current IL is also generated in the battery current Ib, and the internal current of the secondary battery BAT is increased. Passes through impedance 5.

  Since the current square value increases as the ripple current increases, the amount of heat generated in the internal impedance 5 increases. As a result, the temperature rise of the secondary battery BAT can be promoted. By determining the carrier frequency fx at the time of temperature rise control corresponding to the frequency fmin at which the internal impedance value is minimum as shown in FIG. 5, the amplitude of the ripple current can be increased. The secondary battery BAT can be heated.

  During the temperature rise control of the secondary battery, the capacitor C2 connected to the power supply wiring PL is used as a power buffer that temporarily stores the discharge power from the secondary battery BAT. That is, at the time of temperature rise control, reactor current IL can be generated as an AC current without inputting / outputting electric power to / from a load constituted by inverter 14 and AC motor M1.

Here, the relationship between the carrier frequency and the ripple current amplitude will be described with reference to FIG.
Referring to FIG. 8, during the on period of IGBT element Q2 in the lower arm (the off period of IGBT element Q1), reactor current IL has a slope (Vl / L) determined by inductance L of reactor L1 and DC voltage Vl. To rise. On the other hand, during the ON period of IGBT element Q1 of the upper arm, reactor current IL decreases with a slope ((Vl−Vm) / L) determined by inductance L and voltage difference (Vm−Vl). For this reason, when the carrier frequency is decreased from fo to fx, that is, the carrier period is expanded from To to Tx, the rise or decrease period of the reactor current IL is expanded, so that the ripple current amplitude Irp is increased.

  Note that feedback voltage command calculation unit 52 in FIG. 2 preferably fixes feedback voltage command Vcn to a predetermined value. If it does in this way, the behavior of the ripple current at the time of temperature rising control can be stabilized. In particular, if the duty ratio is controlled to 50%, that is, the ON periods of the IGBT elements Q1 and Q2 are equal, the slope of the ripple current can be easily adjusted between the current rising period and the current decreasing period, so that the operation is further improved. Become stable.

  As described above, by increasing the ripple current amplitude Irp, the temperature rise of the secondary battery BAT can be promoted, while the instantaneous value of the reactor current IL increases. As a result, an overcurrent exceeding the allowable maximum current Imax of the components of converter 12, typically the rated maximum current of IGBT elements Q <b> 1 and Q <b> 2, may cause equipment damage to converter 12. .

  That is, if the inductance of the reactor L1 is set based only on the normal carrier frequency fo (fo = 1 / To), the components (typically switching elements) of the converter 12 are used during the temperature rise control of the secondary battery BAT. It should be noted that there is a risk of damage. Here, during the temperature rise control, the DC voltage Vm can be predicted by fixing the duty ratio as described above. Therefore, the ripple current amplitude Irp can be adjusted by the inductance of the reactor L1. .

  Referring to FIG. 9, in the power supply system according to the embodiment of the present invention, the ripple current amplitude Irp at the time of temperature increase control (carrier cycle = Tx) predicted as described above is lower than the allowable maximum current Imax. Thus, the inductance of the reactor L1 is determined.

  With such a configuration, in the power supply system according to the embodiment of the present invention, the temperature rise control of the secondary battery is easily performed by adjusting the carrier frequency, and the components of converter 12 in the temperature rise control are controlled. Damage can be prevented.

  Regarding the correspondence between the present embodiment and the configuration of the present invention, converter 12 corresponds to the “voltage converter” in the present invention, and control device 30 corresponds to the “control device” in the present invention. Also, the feedback voltage command calculation unit 52, the duty ratio control unit 54, the determination unit 56, and the frequency adjustment unit 57 in FIG. 2 are “voltage command calculation unit”, “duty ratio control unit”, “determination unit”, and “frequency”. It corresponds to the “adjustment unit”.

  In this embodiment, a permanent magnet motor mounted for driving a vehicle in an electric vehicle (hybrid vehicle, electric vehicle, fuel cell vehicle, etc.) is assumed as an AC motor serving as a load of the motor drive system. The present invention can also be applied to a configuration in which an arbitrary AC motor used for devices other than the above is used as a load. Further, the voltage converter will be described in a confirming manner that the present invention can be applied without particularly limiting the circuit configuration as long as it includes a reactor.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  5 Internal impedance, 10 Battery sensor, 11, 13 Voltage sensor, 12 Converter, 14 Inverter, 15-17 Each phase arm, 24 Current sensor, 30 Control device, 40 Motor control phase voltage calculation unit, 42 PWM signal conversion unit, 50 inverter input voltage command calculation unit, 52 feedback voltage command calculation unit, 54 duty ratio control unit, 56 determination unit, 57 frequency adjustment unit, 100 motor drive device, BAT secondary battery, C1, C2 capacitor, CW carrier wave, D1 D8 Reverse parallel diode, fc carrier frequency, fmin frequency (minimum internal impedance), Fwu request flag (temperature control), GL ground wiring, Ib battery current, IL reactor current, Imax allowable maximum current, Irp ripple current amplitude, L1 reactor , M1 Current motor, MCRT motor current, MRN motor speed, N1 node, PL power supply wiring, PWD signal (converter control), PWMI signal (inverter control), Q1-Q8 IGBT element (switching element), SE signal (relay control), SR1, SR2 System relay, Tb battery temperature, Tc carrier cycle, To carrier cycle (normal time), Tx carrier cycle (during temperature rise control), TR torque command value, Vb DC voltage, Vcn feedback voltage command, Vdccom voltage command value , Vl DC voltage, Vm DC voltage.

Claims (5)

A secondary battery,
A voltage converter for converting a DC voltage from the secondary battery;
A control device for controlling the voltage converter,
The voltage converter is
A power switching element that is on / off controlled in a cycle according to the carrier frequency;
A reactor connected in series with the switching element with respect to the secondary battery,
The controller is
A determination unit for determining whether temperature increase control of the secondary battery is necessary;
When it is determined that the temperature raising control is necessary, the carrier frequency is set to the first frequency set in advance according to the frequency characteristic of the internal impedance of the secondary battery, while the temperature raising control is necessary. A frequency adjustment unit for setting the carrier frequency to a second frequency higher than the first frequency,
The internal impedance at the first frequency is lower than the internal impedance at the second frequency;
The inductance value of the reactor is determined so that the amplitude of the ripple component of the current flowing through the reactor when the carrier frequency is the first frequency does not exceed the maximum allowable current of components on the current path. Power system. The reactor is electrically connected between a positive electrode and a first node of the secondary battery,
The power switching element is:
A first switching element electrically connected between a power supply line to which a capacitor is connected and the first node;
A second switching element electrically connected between a ground wiring connected to a negative electrode of the secondary battery and the first node;
The controller is
The power supply system according to claim 1, further comprising a duty ratio control unit that generates a signal for complementarily turning on and off the first and second switching elements in accordance with a duty ratio command value. The controller is
While the temperature increase control is performed, the duty ratio command value is fixed to a predetermined value, and when the temperature increase control is not performed, the duty ratio command value is set so that the voltage of the power supply line matches the voltage command value. The power supply system according to claim 2, further comprising a voltage command calculation unit for adjusting.   The power supply system according to claim 1, wherein the first frequency is determined corresponding to a frequency at which the internal impedance is minimized.   The inductance of the reactor is set so that the amplitude value of the ripple component of the current flowing through the reactor when the carrier frequency is the first frequency does not exceed the maximum allowable current of the power switching element. The power supply system of any one of Claims 1-4.

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