JP2013017324A - Power-supply system and method of controlling the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the power loss of a converter and suppress the ripple of a current inputted to and outputted from a power-storage device, in a power-supply system having the converter and an inverter.SOLUTION: A bypass circuit 40 forms a current path bypassing a converter 12 between a power-storage device B and a power line 7 by turning on a bypass relay BRL. In an operating state that does not require a step-up operation by the converter 12, a first mode, which operates the bypass circuit 40 and stops the converter 12, and a second mode, which stops the bypass circuit 40 and operates the converter 12, are selected according to the amplitude of a DC current IH at the power line 7. In the second mode, the converter 12 forms a current path through a reactor L1 between the power-storage device B and the power line 7 by fixing a switching element Q1 to the on-state.

Description

  The present invention relates to a power supply system and a control method therefor, and more particularly to control of a power supply system that drives and controls an electric motor using a converter and an inverter.

  Japanese Patent Application Laid-Open No. 2005-160284 (Patent Document 1), Japanese Patent Application Laid-Open No. 2003-219688 (Patent Document 2), and Japanese Patent Application Laid-Open No. 2002-118987 are disclosed in which a DC voltage is converted into an AC voltage by an inverter to drive an electric motor. (Patent Document 3), JP-A 2010-166790 (Patent Document 4), JP-A 2007-104778 (Patent Document 5), and the like.

  Furthermore, Japanese Patent Laying-Open No. 2005-160284 (Patent Document 1) and Japanese Patent Laying-Open No. 2010-166790 (Patent Document 4) propose a configuration capable of boosting a DC side voltage input to an inverter by a converter. In particular, Japanese Patent Laying-Open No. 2005-160284 (Patent Document 1) describes a configuration in which a bypass circuit of a booster circuit (converter) disposed between a battery and an inverter is provided. And, when the booster circuit does not perform the boosting operation, the control for reducing the power loss by turning on the bypass circuit is described.

JP 2005-160284 A JP 2003-219688 A JP 2002-118987 A JP 2010-166790 A JP 2007-104778 A

  In the configuration of Patent Document 1, when the booster circuit (converter) is bypassed, current is input / output between the motor and the battery via switching by the inverter. Therefore, a high-frequency current corresponding to the switching frequency in the inverter is superimposed on the current flowing through the battery (battery current). That is, bypassing the converter reduces power loss while increasing battery current ripple. When the current ripple increases, the amount of heat generated when the same power (average value) is input to and output from the battery increases. Thereby, there exists a possibility that the output performance of a battery may fall or deterioration of a battery may progress.

  The present invention has been made to solve such problems. An object of the present invention is to reduce power loss in a converter and to store a power storage device (battery) in a power supply system having a converter and an inverter. This is to achieve both suppression of ripples in the input / output current.

In one aspect of the present invention, a power supply system includes a power storage device, a converter, an inverter, a bypass circuit, and a control unit for controlling the converter and the bypass circuit. The converter is configured to perform DC voltage conversion between the power line and the power storage device. The converter includes a switching element and a reactor electrically connected between the power line and the power storage device. The inverter is configured to perform DC / AC power conversion between the power line and the AC motor by on / off control of a plurality of switching elements. The bypass circuit is configured to electrically connect the power storage device and the power line so as to bypass the converter during operation. The control unit is configured to stop the converter and operate the bypass circuit when the boosting operation by the converter is unnecessary, and to electrically connect the power line and the power storage device via the reactor while stopping the bypass circuit. The second mode in which the converter is operated so as to be connected to the power supply is selectively executed according to the ripple current in the power line.

  Preferably, the control unit selects one of the first mode and the second mode according to at least the operating state of the AC motor.

  Preferably, the control unit selects one of the first mode and the second mode according to the operating state of the AC motor and the switching frequency of the plurality of switching elements of the inverter.

  In another aspect of the present invention, there is provided a method for controlling a power supply system, wherein the power supply system includes a power storage device, a converter for performing DC voltage conversion between the power line and the power storage device, and the power line and the AC motor. And an inverter for performing DC / AC power conversion by on / off control of a plurality of switching elements. The control method includes a first determination step for determining whether or not the boost operation by the converter is necessary, and an operation state in which the ripple current in the power line is large when the boost operation is unnecessary. A second determination step for determining whether or not there is an electrical connection between the power storage device and the power line so that the converter is stopped and the converter is bypassed when the ripple current is not in the large operating state When the operation of the bypass circuit configured as described above and the operation state where the ripple current is large, the bypass circuit is stopped and the converter is electrically connected to the power line and the power storage device via the reactor in the converter. Operating.

  Preferably, in the second determination step, it is determined whether or not the ripple current is in an operating state depending on at least the operating state of the AC motor.

  Preferably, in the second determination step, it is determined whether or not the ripple current is in an operation state depending on an operation state of the AC motor and switching frequencies of the plurality of switching elements of the inverter.

  According to the present invention, in a power supply system having a converter and an inverter, it is possible to achieve both reduction of power loss in the converter and suppression of ripple of current input to and output from the power storage device (battery).

1 is a schematic configuration diagram of a power supply system according to an embodiment of the present invention. FIG. 2 is a conceptual waveform diagram for explaining current behavior in a bypass mode in the power supply system shown in FIG. 1. It is a flowchart which shows the control processing of the converter and bypass circuit in the power supply system according to the embodiment of the present invention. It is a conceptual diagram which shows the relationship between the operating state of an alternating current motor when the power supply system is operated without the step-up operation, and the magnitude of the ripple current.

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

  FIG. 1 is a schematic configuration diagram of a power supply system according to an embodiment of the present invention. FIG. 1 illustrates a power supply system for driving and controlling the AC motor M1.

  Referring to FIG. 1, power supply system 100 includes a DC voltage generation unit 10 #, a smoothing capacitor C0, an inverter 14, and a control device 30.

  AC motor M1, which is a load of the power supply system, is a driving motor that generates torque for driving the driving wheels of an electric vehicle such as a hybrid vehicle or an electric vehicle. In other words, in the present embodiment, the electric vehicle includes all vehicles equipped with a motor for generating wheel driving force, including an electric vehicle not equipped with an engine. Note that AC motor M1 is generally configured to have both functions of an electric motor and a generator. Further, this AC motor M1 may be configured to have a function of a generator driven by an engine in a hybrid vehicle. Further, AC electric motor M1 may operate as an electric motor for the engine, and may be incorporated in a hybrid vehicle as one that can start the engine, for example.

  DC voltage generation unit 10 # includes a power storage device B, system relays SR1 and SR2, a smoothing capacitor C1, a converter 12, and a bypass circuit 40.

  The power storage device B includes a secondary battery such as nickel metal hydride or lithium ion, an electric double layer capacitor, or a combination thereof. The voltage (Vb), current, and temperature of the power storage device B are detected by the sensor 10 provided in the power storage device B. A value detected by the sensor 10 is output to the control device 30.

  System relay SR1 is connected between the positive terminal of power storage device B and power line 6, and system relay SR2 is connected between the negative terminal of power storage device B and power line 5. System relays SR1 and SR2 are turned on / off by signal SE from control device 30. Smoothing capacitor C <b> 1 is connected between power line 6 and power line 5. The DC voltage VL between the power line 6 and the power line 5 is detected by the voltage sensor 11. The value detected by the voltage sensor 11 is sent to the control device 30.

  Converter 12 has a so-called boost chopper configuration, and includes a reactor L1, power semiconductor switching elements Q1, Q2, and diodes D1, D2.

  Power semiconductor switching elements Q 1 and Q 2 are connected in series between power line 7 and power line 5. On / off of power semiconductor switching elements Q 1 and Q 2 is controlled by switching control signals S 1 and S 2 from control device 30.

  In the embodiment of the present invention, an IGBT (Insulated Gate Bipolar Transistor), a power MOS (Metal Oxide Semiconductor) transistor, or a power bipolar transistor is used as a power semiconductor switching element (hereinafter simply referred to as “switching element”). Etc. can be used. Anti-parallel diodes D1, D2 are arranged for switching elements Q1, Q2.

  Reactor L1 is connected between a connection node of switching elements Q1 and Q2 and power line 6. Further, the smoothing capacitor C0 is connected between the power line 7 and the power line 5.

  Inverter 14 includes a U-phase arm 15, a V-phase arm 16, and a W-phase arm 17 provided in parallel between power line 7 and power line 5. Each phase arm is composed of switching elements connected in series between power line 7 and power line 5. For example, U-phase arm 15 includes switching elements Q3 and Q4, V-phase arm 16 includes switching elements Q5 and Q6, and W-phase arm 17 includes switching elements Q7 and Q8. Further, antiparallel diodes D3 to D8 are connected to switching elements Q3 to Q8, respectively. Switching elements Q3 to Q8 are turned on / off by switching control signals S3 to S8 from control device 30.

  An intermediate point of each phase arm is connected to each phase end of each phase coil of AC electric motor M1. Typically, AC electric 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 are commonly connected to a midpoint. Furthermore, the other end of each phase coil is connected to the midpoint of the switching elements of each phase arm 15-17.

  Converter 12 is basically controlled such that switching elements Q1 and Q2 are turned on and off in a complementary manner in each switching period. Hereinafter, the operation of converter 12 in which switching elements Q1 and / or Q2 are controlled to be turned on / off is also referred to as “switching operation”.

  Converter 12 controls the voltage conversion ratio (ratio of VH and VL) by controlling the on period ratio (duty ratio) with respect to the switching period of switching elements Q1 and Q2 during the switching operation. That is, the voltage conversion ratio (VH / VL) is set so that the DC voltage VH of the power line 7 (this DC voltage corresponding to the input voltage to the inverter 14 is hereinafter also referred to as “system voltage”) matches the voltage command value VHr. ) Can be controlled.

  During the boosting operation of converter 12, AC electric motor M1 can be driven as VH> VL (Vb), that is, with a voltage higher than the output voltage of power storage device B. Thereby, since the current of the inverter 14 with respect to the output of the same power can be reduced, the operable region of the AC motor M1 can be expanded in the high output direction. Converter 12 can perform bidirectional DC voltage conversion corresponding to both the regenerative and power running current directions by switching switching elements Q1 and Q2 alternately and alternately.

  When the output of AC motor M1 is not high, AC motor M1 can be driven by DC voltage VL (Vb) without being boosted by converter 12. In this case, if switching elements Q1 and Q2 are fixed to ON and OFF in converter 12, VH = VL (voltage conversion ratio = 1.0) can be obtained. Hereinafter, such an operation mode of the converter 12 is also referred to as an “upper arm ON mode”. In the upper arm ON mode, no switching loss occurs in the switching elements Q1 and Q2, so that the efficiency is higher than that in the normal switching operation. Therefore, when the boosting operation by converter 12 is not necessary, converter 12 operates in the upper arm ON mode.

  The smoothing capacitor C0 smoothes the DC voltage on the power line 7. The voltage sensor 13 detects the voltage across the smoothing capacitor C 0, that is, the system voltage VH, and outputs the detected value to the control device 30.

Bypass circuit 40 includes a power line 8 for bypassing converter 12 to electrically connect power line 6 and power line 7, and a bypass relay BRL inserted and connected to power line 8. The bypass relay BRL is turned on / off according to the signal SBE from the control device 30. In operation, bypass circuit 40 turns on bypass relay BRL to form a current path bypassing converter 12 between power storage device B and power line 7. On the other hand, when converter 40 is stopped, bypass circuit 40 turns off bypass relay BRL. Thereby, a current path passing through converter 12 is formed between power storage device B and power line 7.

  When the torque command value of AC motor M1 is positive (Trqcom> 0), inverter 14 operates on power line 7 by the switching operation of switching elements Q3 to Q8 in response to switching control signals S3 to S8 from control device 30. The AC motor M1 is driven so as to convert the DC voltage into an AC voltage and output a positive torque. Further, when the torque command value of AC electric motor M1 is zero (Trqcom = 0), inverter 14 converts the DC voltage to the AC voltage by the switching operation in response to switching control signals S3 to S8, and the torque is zero. The AC motor M1 is driven so that Thus, AC electric motor M1 is driven to generate zero or positive torque designated by torque command value Trqcom.

  Further, during regenerative braking of an electric vehicle equipped with power supply system 100, torque command value Trqcom of AC electric motor M1 is set to be negative (Trqcom <0). In this case, the inverter 14 converts the AC voltage generated by the AC motor M1 into a DC voltage by a switching operation in response to the switching control signals S3 to S8, and converts the converted DC voltage (system voltage) to the smoothing capacitor C0. To the converter 12 via 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.

  Current sensor 24 detects a current (phase current) flowing through AC electric motor M <b> 1 and outputs the detected value to control device 30. Since the sum of instantaneous values of the three-phase currents iu, iv, and iw is zero, the motor currents for two phases (for example, the V-phase current iv and the W-phase current iw) are detected as shown in FIG. You may arrange in.

  The rotation angle sensor (resolver) 25 detects the rotor rotation angle ANG of the AC electric motor M1 and sends the detected rotation angle ANG to the control device 30. The control device 30 can calculate the rotation speed and the rotation frequency ωe of the AC motor M1 based on the rotation angle ANG. Note that the rotation angle sensor 25 may be omitted by directly calculating the rotation angle ANG from the motor voltage or current in the control device 30.

The control device 30 is configured by an electronic control unit (ECU), and is powered by software processing by executing a program stored in advance by a CPU (Central Processing Unit) (not shown) and / or hardware processing by a dedicated electronic circuit. Control the operation of the system 100.

  As a representative function, the control device 30 is detected by the detection value by the sensor 10, the torque command value Trqcom, the DC voltage VL detected by the voltage sensor 11, the system voltage VH detected by the voltage sensor 13, and the current sensor 24. The operation of the converter 12 and the inverter 14 is controlled based on the motor currents iv and iw, the rotation angle ANG from the rotation angle sensor 25, and the like. That is, switching control signals S1 to S8 for controlling converter 12 and inverter 14 as described above are generated and output to converter 12 and inverter 14.

Specifically, control device 30 performs feedback control of system voltage VH, and generates switching control signals S1 and S2 such that system voltage VH matches voltage command value VHr. Note that an optimum value is set for voltage command value VHr in accordance with the operating state (for example, torque and rotational speed) of AC electric motor M1. Generally, it is necessary to increase the voltage command value VHr at the time of high output of the AC motor M1. That is, whether or not boosting of converter 12 is necessary is basically determined based on the operating state of AC electric motor M1.

  Control device 30 generates switching control signals S3 to S8 and outputs them to inverter 14 so that AC electric motor M1 outputs a torque according to torque command value Trqcom. Further, control device 30 controls on / off of system relays SR1 and SR2 in response to the start / stop of power supply system 100. Any known method can be applied to the torque control method.

  When the AC motor M1 is driven and controlled, a current IH corresponding to the power input / output between the AC motor M1 and the power storage device B flows through the power line 7. The product of DC voltage VH and DC current IH corresponds to the electric power input / output between AC electric motor M1 and power storage device B.

  In the power supply system according to the present embodiment, a bypass circuit 40 of converter 12 is provided. Therefore, when the boosting operation by the converter 12 is unnecessary, in addition to controlling the converter 12 in the upper arm ON mode, the operation mode in which the bypass circuit 40 is operated to stop the converter 12 (hereinafter also referred to as “bypass mode”). Is possible.

  In the bypass mode, the power consumption of the converter 12 is cut, so that the efficiency can be improved. Thereby, in an electric vehicle, the travel distance by the stored electric power of power storage device B can be extended.

FIG. 2 is a conceptual waveform diagram for explaining the current behavior in the bypass mode.
Referring to FIG. 2, current IH flowing through power line 7 has a waveform in which ripple component Ir (hereinafter also referred to as ripple current Ir) is superimposed on average current IHav, which is a DC component. In the bypass mode, since the current IH flows without going through the converter 12, the current fluctuation accompanying the on / off control (switching) by the switching elements Q3 to Q8 in the inverter 14 appears as the ripple current Ir as it is.

  The ripple current Ir depends on the current level (average current IHav) and the switching frequency in the inverter 14. Therefore, in the high output state of AC electric motor M1, that is, in the state of high torque and / or high rotational speed, ripple current Ir is relatively large. Particularly when the control for lowering the carrier frequency (that is, the switching frequency) of the inverter is combined in order to reduce the switching loss at the time of high output, the ripple current Ir further increases. The ripple current Ir flows through the power storage device B as it is. When the current ripple of power storage device B increases, the amount of heat generation increases with respect to the input and output of the same power.

  When the inverter 14 performs a switching operation, that is, when the DC voltage VH is controlled in accordance with the voltage command value VHr, the current IH is also switched by turning on and off the switching elements Q1 and / or Q2, so that the ripple current Ir Is relatively small.

  When converter 12 is operating in the upper arm ON mode, reactor L1 is included in the current path between power line 7 and power storage device B. Therefore, the ripple current Ir becomes smaller than that in the bypass mode.

When the boosting operation of the converter 12 is unnecessary, the bypass mode is advantageous in terms of power loss when comparing the bypass mode and the upper arm ON mode. On the other hand, in the bypass mode, there is a concern that heat generation of power storage device B may increase due to an increase in ripple current Ir. For this reason, in order to suppress deterioration of the electrical storage device B, it may be necessary to limit the charge / discharge power of the electrical storage device B.

  Therefore, in the power supply system according to the present embodiment, the operation of bypass circuit 40 is controlled so that the ripple current does not become excessive in an operating state where converter boosting is unnecessary.

  FIG. 3 is a flowchart showing control processing of the converter and the bypass circuit in the power supply system according to the embodiment of the present invention. The control process shown in FIG. 3 is repeatedly executed by the control device 30 at predetermined intervals. That is, the control process of each step in the flowchart of FIG. 3 is realized by a control program executed by a predetermined program executed by the control device 30 and / or an electronic circuit (hardware) in the control device 30.

  In step S100, control device 30 determines whether or not the operation mode does not require boosting. For example, the determination in step S100 is performed based on voltage command value VHr of DC voltage VH.

  When the operation state requires boosting (when NO is determined in S100), the switching operation by the converter 12 is necessary. Therefore, control device 30 advances the processing to step S120, turns off bypass circuit 40, and causes converter 12 to perform a switching operation. Thus, the on / off of the switching elements Q1, Q2 is controlled so that the DC voltage VH matches the voltage command value VHr.

  On the other hand, when the operation state does not require boosting (when YES is determined in S100), control device 30 proceeds to step S110 to determine whether or not the operation state has a large ripple current when the bypass mode is applied. To do.

  As described above, the magnitude of the ripple current Ir in the bypass mode depends on the operating state of the AC motor M1 and the switching frequency (carrier frequency) in the inverter 14.

  FIG. 4 conceptually shows the relationship between the operating state of AC electric motor M1 and the magnitude of ripple current when the power supply system is operated without a boosting operation.

  Referring to FIG. 4, AC electric motor M1 operates in an operation region inside maximum output line 150 without the boost operation. Torque T0 is the maximum value of torque that AC motor M1 can generate without boosting operation. For example, the torque T0 is determined according to the maximum allowable current in a circuit element such as a switching element. The rotation speed N0 is the maximum value of the rotation speed when the AC motor M1 is operated without a boost operation. For example, the rotational speed N0 is determined according to the induced voltage generated by the AC motor M1.

Within the operating region shown in FIG. The ripple current Ir increases as the torque and the rotational speed increase. A map that associates the magnitude of the ripple current Ir in the bypass mode with the combination of the torque and the rotational speed of the AC motor M1 (ie, the operating state) can be created in advance by actual machine experiments or the like. Since the switching frequency of the inverter 14 also affects Ir, a map for estimating the magnitude of the ripple current Ir with respect to the operating state of the AC motor M1 and the switching frequency of the inverter 14 can be created.

In addition, in order to reduce the switching loss at the time of high output, when the control that variably sets the switching frequency according to the combination of the torque and the rotational speed of the AC motor M1 (that is, the operating state) is adopted. The map for estimating the magnitude of the ripple current Ir with respect to the operating state of the AC motor M1 can be created uniformly.

  The determination in step S110 is, for example, an estimated value of ripple current obtained by referring to the map based on the operating state of AC motor M1 (or the operating state of AC motor M1 and the switching frequency of the inverter), and a predetermined determination value. Can be performed by comparison.

  Alternatively, the determination in step S110 when the bypass mode is selected, that is, the determination of the transition from the bypass mode to the upper arm ON mode may be performed based on the actually measured value of the ripple current Ir. For example, in bypass mode, ripple current Ir can be detected based on the detected value of current Ib of power storage device B.

  Control device 30 proceeds to step S130 and selects the upper arm ON mode when the boost current is not needed and the ripple current is in an operating state with a large ripple current (YES in S110). Thereby, control device 30 generates signal SBE to turn off bypass relay BRL in order to stop bypass circuit 40. Furthermore, a control command is issued to converter 12 so that switching element Q1 is fixed on and switching element Q2 is fixed off. As a result, a current path via reactor L1 is formed, so that ripple current Ir, that is, current ripple of power storage device B is suppressed.

  On the other hand, control device 30 proceeds to step S140 and selects the bypass mode when the boost current is not required and the ripple current is not in an operating state with a large ripple current (NO determination in S110). Thereby, in order to operate bypass circuit 40, control device 30 generates signal SBE to turn on bypass relay BRL. Further, a stop command is issued to converter 12. Thereby, switching elements Q1 and Q2 of converter 12 are fixed to OFF.

  As a result, when the boosting operation is unnecessary, in the operating state where the ripple current Ir does not increase even if the converter 12 is bypassed, the converter 12 is stopped by operating the bypass circuit 40, thereby improving the efficiency of the power supply system. Can be increased.

  On the other hand, in an operating state where the ripple current Ir increases when the converter 12 is bypassed, the current ripple can be reduced while suppressing the power loss in the converter 12 by operating the converter 12 in the upper arm ON mode. . Thereby, since the restriction | limiting of the charging / discharging electric power by the temperature rise of the electrical storage apparatus B can be avoided, the electric power of the electrical storage apparatus B can be used effectively.

  Thus, according to the power supply system according to the present embodiment, in the configuration having the converter and the inverter, both reduction of power loss in the converter and suppression of ripple of current input to and output from the power storage device can be achieved. .

  Note that the power supply system according to the present embodiment also has a general-purpose merit that can be commonly applied to systems having different output ratings of AC electric motor M1. For example, a power supply system designed for a hybrid vehicle having a relatively high output rating of the AC motor M1 can be applied to an electric vehicle having a relatively low output rating of the AC motor M1.

When a power supply system (converter and inverter) set in accordance with a high output system is applied to a low output system, the output of the AC motor M1 serving as a load is low, and therefore the frequency at which an operation state requiring no boost is required. Becomes higher. For this reason, if bypass circuit 40 is not arranged, converter 12 operates continuously in the upper arm ON mode in this operation state. At this time, since the same current path is continuously formed in the converter 12, circuit elements such as the switching element Q1 (diode D1) and the reactor L1 generate heat due to continuous energization. As a result, in order to prevent an excessive temperature rise of the circuit element, there is a possibility that it is necessary to limit the current, that is, limit the charge / discharge power of the power storage device B. This restriction leads to an output restriction of the AC motor M1.

  On the other hand, in the power supply system according to the present embodiment, the bypass circuit 40 is provided, and the bypass mode and the upper arm ON mode can be selectively applied according to the ripple current. It is not necessary to operate the converter 12 at all times. Therefore, when applied to a low-output system, it is possible to reduce power loss while avoiding an increase in ripple current, and to avoid output limitation due to a temperature rise of circuit elements of converter 12. That is, versatility is enhanced in the power supply system according to the present embodiment.

  On the other hand, when applied to a high output system, the power consumption of the converter 12 can be suppressed while avoiding an increase in ripple current by using the bypass circuit 40 when the boosting operation is unnecessary. That is, the efficiency of the power supply system can be further increased as compared with the configuration in which the bypass circuit 40 is not provided.

  In FIG. 1, the converter 12 is described as a step-up chopper circuit. However, the converter 12 can have any circuit configuration as long as the current ripple in the case of no boost operation is smaller than that in the bypass circuit operation.

  Also, with regard to the AC motor serving as the load of the power supply system, in the present embodiment, a permanent magnet motor mounted for driving a vehicle in an electric vehicle (hybrid vehicle, electric vehicle, etc.) is assumed. The present invention can also be applied to a configuration in which an arbitrary AC motor used is a load.

  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.

  The present invention can be applied to a power supply system that drives and controls an electric motor using a converter and an inverter.

  5-8 power line, 10 sensor, 10 # DC voltage generator, 11, 13 voltage sensor, 12 converter, 14 inverter, 15-17 each phase arm, 24 current sensor, 25 rotation angle sensor, 30 control device, 40 bypass circuit , 100 power supply system, 150 maximum output line (no boost operation), ANG rotor rotation angle, B power storage device, BRL bypass relay, C0, C1 smoothing capacitor, D1, D2 diode, D1 antiparallel diode, IH DC current, IHav average Current, Ir ripple current, L1 reactor, M1 AC motor, N0 rotation speed, Q1-Q8 power semiconductor switching element, S1-S8 switching control signal, SBE, SE signal (relay), SR1, SR2 system relay, Trqcom torque command Value, VH Flow voltage (system voltage), iu, iv, iw three-phase currents (motor current).

Claims (6)

A power storage device;
A converter for performing DC voltage conversion between a power line and the power storage device,
The converter includes a switching element and a reactor electrically connected between the power line and the power storage device,
An inverter for performing direct current alternating current power conversion by on / off control of a plurality of switching elements between the power line and the alternating current motor;
A bypass circuit for electrically connecting the power storage device and the power line so as to bypass the converter during operation;
A control unit for controlling the converter and the bypass circuit;
The controller is
A first mode in which the converter is stopped and the bypass circuit is operated when the converter does not require boosting; and the power line and the power storage device through the reactor while the bypass circuit is stopped. A power supply system configured to selectively execute a second mode in which the converter is operated so as to be electrically connected to each other according to a ripple current in the power line.   The power supply system according to claim 1, wherein the control unit selects one of the first mode and the second mode according to at least an operating state of the AC motor.   2. The control unit according to claim 1, wherein the control unit selects one of the first mode and the second mode according to an operating state of the AC motor and a switching frequency of the plurality of switching elements of the inverter. Power system. A power storage device, a converter for performing DC voltage conversion between the power line and the power storage device, and an inverter for performing DC AC power conversion by on / off control of a plurality of switching elements between the power line and the AC motor. A power supply system control method comprising:
A first determination step for determining whether or not the boost operation by the converter is in an operating state;
A second determination step of determining whether or not an operation state in which a ripple current in the power line is large when the boost operation is unnecessary is an operation state;
When the ripple current is not in an operating state, the converter is stopped, and a bypass circuit configured to electrically connect the power storage device and the power line so as to bypass the converter is operated. Steps,
Stopping the bypass circuit and operating the converter to electrically connect the power line and the power storage device via a reactor in the converter when the ripple current is in an operating state. , Power system control method.   5. The method of controlling a power supply system according to claim 4, wherein in the second determination step, it is determined whether or not the ripple current is in an operation state with a large ripple current according to an operation state of the AC motor.   5. The second determination step determines whether or not the ripple current is in an operating state depending on an operating state of the AC motor and switching frequencies of the plurality of switching elements of the inverter. Power system control method.

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