WO2016059708A1

WO2016059708A1 - Power supply system and control method for power supply system

Info

Publication number: WO2016059708A1
Application number: PCT/JP2014/077605
Authority: WO
Inventors: 充彦松本
Original assignee: 日産自動車株式会社
Priority date: 2014-10-16
Filing date: 2014-10-16
Publication date: 2016-04-21

Abstract

This power supply system, in which at least one power source is selected from a series power source consisting of a first power source and second power source connected in series, and power is supplied to a load, includes a secondary battery that charges or discharges power, a fuel cell that is connected in series to the secondary battery, and a power conversion means that converts the power output from at least one of the power sources of the series power source into AC power. In the power supply system, a positive electrode terminal of the secondary battery is connected to a first power source terminal of the power conversion means as a positive electrode terminal of the series power source, and the positive electrode terminal of the fuel cell is connected, along with the negative electrode terminal of the secondary battery, to a second power source terminal of the power conversion means which is between the positive electrode terminal and negative electrode terminal of the series power source.

Description

Power supply system and control method of power supply system

The present invention relates to a power supply system that supplies power to a load by selecting at least one of the series power supplies and a control method for the power supply system.

As a system for supplying electric power to a motor, in order to secure a voltage higher than the induced voltage generated in the motor, a series power supply in which a fuel cell and a secondary battery are connected in series is connected to a matrix converter, and the series power supply is There are systems that use and supply power to the motor.

JP 4589056B discloses a power conversion device in which a fuel cell of a series power supply is connected to the positive side of a matrix converter, and a battery as the other power source is connected to the negative side of the matrix converter.

In the above power converter, when the power supplied from the fuel cell to the motor is assisted by the battery power, a current larger than the current that can be discharged from the battery is supplied from the series power supply to the motor. Therefore, when power is supplied from the series power supply to the motor, switching control is performed to return the current from the motor to the negative terminal of the fuel cell through the power line between the negative terminal of the fuel cell and the positive terminal of the battery. Is done.

In order to execute such switching control, it is necessary to increase the voltage of the power supply, and since the current flowing to the motor increases, it is necessary to take measures in consideration of the temperature rise of the converter, which increases the manufacturing cost. There is a problem that it ends up.

The present invention has been made paying attention to such a problem, and a power supply system and a control of the power supply system that reduce wasteful processing performed when power is supplied from a series power supply with a simple configuration. It aims to provide a method.

According to an embodiment of the present invention, a power supply system that selects at least one power source among series power sources in which a first power source and a second power source are connected in series and supplies power to a load is charged or discharged. Secondary battery, a fuel cell connected in series with the secondary battery, and power conversion means for converting power output from at least one of the series power supplies into AC power. In the power supply system, the positive terminal of the secondary battery is connected to the first power terminal of the power conversion means as the positive terminal of the series power supply, and the positive terminal of the fuel cell is connected to the positive terminal and the negative terminal of the series power supply. It connects with the negative electrode terminal of the said secondary battery with respect to the 2nd power supply terminal of the said power conversion means between terminals.

FIG. 1 is a circuit diagram showing a configuration of a power supply system according to an embodiment of the present invention. FIG. 2 is a block diagram illustrating a functional configuration of a controller that controls the power supply system. FIG. 3 is a block diagram illustrating a detailed configuration of a control unit that controls power generation of the fuel cell. FIG. 4 is a block diagram illustrating an example of a detailed configuration of a control unit that controls voltage distribution of the series power supply. FIG. 5 is a block diagram illustrating an example of a detailed configuration of a control unit that controls the motor. FIG. 6A is a diagram illustrating an example of voltage waveforms of a series power supply and a single power supply that generate a U-phase voltage signal supplied to the motor. FIG. 6B is a diagram illustrating an example of voltage waveforms of a series power supply and a single power supply when charging power to the secondary battery. FIG. 7 is a diagram illustrating a modulation rate for modulating the voltage of the series power supply and the single power supply for the U-phase voltage signal. FIG. 8 is a diagram illustrating a technique for generating a PWM signal according to a modulation rate for a series power supply and a single power supply. FIG. 9A is a diagram illustrating switching control executed by the series power converter when the torque required for the motor increases. FIG. 9B is a diagram illustrating an example of switching control executed by the series power converter when the torque required for the motor is reduced.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a diagram illustrating a configuration of a power supply system 100 according to an embodiment of the present invention.

The power supply system 100 selects at least one of the series power supplies in which two power supplies are connected in series and supplies power to the electric load. In the following, among the series power supplies, the positive power supply is referred to as a first power supply, and the negative power supply is referred to as a second power supply. One of the first power source and the second power source is referred to as a single power source.

The power supply system 100 includes a fuel cell stack 10, a backflow prevention diode 11, an auxiliary machine 12, a control device 13, a secondary battery 20, a control device 21, a series power conversion device 30, and a first power supply capacitor. 41, a second power supply capacitor 42, and a controller 50. The power supply system 100 includes current sensors 111 to 113, a voltage sensor 121 and a voltage sensor 122, and a current sensor 131 and a current sensor 132.

The electric motor 200 is an electric load connected to a series power supply. In the present embodiment, the electric motor 200 is realized by a three-phase AC motor including a U phase, a V phase, and a W phase. For example, a permanent magnet synchronous motor is used as the three-phase AC motor.

The electric motor 200 is mounted on a vehicle and has a function as an electric motor for driving the vehicle and a function as a generator for regenerating a braking force of the vehicle. For this reason, at the time of braking of the vehicle, the electric motor 200 can charge the regenerative power to the secondary battery 20.

The fuel cell stack 10 is a direct current power source for supplying electric power to the electric motor 200. The fuel cell stack 10 is supplied with a cathode gas (oxidant gas) containing oxygen and an anode gas (fuel gas) containing hydrogen to generate electric power according to an electric load.

The fuel cell stack 10 is a stack of a plurality of fuel cells. The fuel cell has an electrolyte membrane, an anode electrode (fuel electrode), and a cathode electrode (oxidant electrode), and the electrolyte membrane is sandwiched between the anode electrode and the cathode electrode. In this fuel cell, an anode gas supplied to the anode electrode and a cathode gas supplied to the cathode electrode cause an electrochemical reaction at the electrolyte membrane to generate electric power. The electrochemical reaction proceeds as follows at both the anode and cathode electrodes.

Anode electrode: 2H ₂ → 4H + + 4e- (1)
Cathode electrode: 4H + + 4e- + O ₂ → 2H ₂ O (2)
In the fuel cell, an electromotive force is generated and water is generated by the electrochemical reactions (1) and (2). Since a plurality of fuel cells are connected in series to the fuel cell stack 10, the sum of the cell voltages generated in each fuel cell becomes the output voltage of the fuel cell stack 10.

The fuel cell stack 10 is supplied with cathode gas and anode gas by a cathode gas supply / discharge device and an anode gas supply / discharge device (not shown), respectively. The cathode gas supply / discharge device includes a compressor that supplies cathode gas to the fuel cell stack 10, a cathode pressure regulating valve that adjusts the pressure of the cathode gas, and the like. The anode gas supply / discharge device includes an anode pressure regulating valve that supplies anode gas to the fuel cell stack 10 from a high-pressure tank that stores the anode gas, a purge valve that discharges anode off-gas from the fuel cell stack 10, and the like.

The backflow prevention diode 11 is connected to the positive electrode terminal 10 </ b> A of the fuel cell stack 10 and prevents a current flowing back to the fuel cell stack 10.

The auxiliary machine 12 is a component that assists the operation of the fuel cell stack 10 and is operated by the electric power output from the fuel cell stack 10. The auxiliary machine 12 includes a cathode compressor that supplies a cathode gas to the fuel cell stack 10 and a cooling water pump that circulates cooling water through the fuel cell stack 10.

The control device 13 controls the operation of the auxiliary machine 12 and is controlled by the controller 50. The control device 13 controls the operation amounts of, for example, a cathode compressor and a cooling water pump.

Further, the control device 13 detects the state quantity of the auxiliary machine 12. The state quantity of the auxiliary machine 12 is a parameter necessary for measuring the power consumption of the auxiliary machine 12. For example, when measuring the power consumption of the cathode compressor, the rotational speed and torque of the cathode compressor are detected. Is done. The control device 13 outputs the detected state quantity to the controller 50.

The secondary battery 20 is a power source for discharging or charging electric power to the electric motor 200. In the present embodiment, the secondary battery 20 is used as a power source that assists the power of the fuel cell stack 10. The secondary battery 20 is realized by, for example, a lithium ion battery.

The control device 21 monitors the charge / discharge state of the secondary battery 20. The control device 21 detects the current flowing through the secondary battery 20 and the voltage of the secondary battery 20, and calculates SOC (State Of Charge) indicating the battery capacity of the secondary battery 20. Further, the control device 21 outputs secondary battery information including the SOC of the secondary battery 20, the temperature of the secondary battery 20, allowable discharge power, and allowable charge power to the controller 50.

The series power converter 30 is power conversion means in which a series power source in which a first power source and a second power source are connected in series is connected in parallel. By supplying the voltage of the series power supply to the electric motor 200 by the series power converter 30, it is possible to ensure a voltage that is not inferior to the induced voltage generated in the electric motor 200.

The series power supply conversion device 30 selects at least one of the series power supplies and connects the selected power supply to the electric load. The series power converter 30 is controlled by the controller 50.

The serial power converter 30 performs switching control for converting the power output from the selected power source into AC power, and supplies the AC power converted by the switching control to the electric motor 200. The series power converter 30 is realized by a three-level inverter, for example.

The series power supply converter 30 is provided with a first power supply terminal 311, a second power supply terminal 312, and a ground terminal 313 for connecting a series power supply in which two power supplies are connected in series.

The first power supply terminal 311 is a terminal to which the positive terminal of the positive power supply among the series power supplies is connected. The second power supply terminal 312 is a terminal to which the positive terminal of the negative power supply and the negative terminal of the positive power supply are connected in the series power supply. The ground terminal 313 is a terminal to which the negative terminal of the negative power supply is connected among the series power supplies.

The series power converter 30 is connected to a U-phase terminal 321 to which a U-phase power line of the electric motor 200 is connected, a V-phase terminal 322 to which a V-phase power line is connected, and a W-phase power line. W-phase terminal 323 is provided.

The serial power converter 30 includes a bidirectional converter 31, a serial power connection 32, and a ground power connection 33.

The bidirectional conversion unit 31 is a second switch unit that connects or blocks between the second power supply terminal 312 and the electric motor 200. The bidirectional conversion unit 31 outputs the voltage of the second power supply terminal 312 to the U-phase terminal 321, the V-phase terminal 322, and the W-phase terminal 323 by switching control of the controller 50, respectively.

The bidirectional conversion unit 31 includes switching

circuits

1u, 1v, and 1w that supply AC power to the electric motor 200, a switching circuit 4u that blocks current flowing from the first power supply terminal 311 and the electric motor 200 to the second

power supply terminal

312, 4v and 4w.

A switching circuit 1u and a switching circuit 4u are connected in series to the U-phase power line Lu.

The switching circuit 1u is a circuit that outputs a voltage supplied from the second power supply terminal 312 to the U-phase power supply line Lu, and includes a transistor Tr and a diode Di. Here, for the sake of convenience, only the transistors and diodes of the switching circuit 1u are denoted by symbols Tr and Di, and the other switching circuits are omitted.

The transistor Tr is a switching element that performs an on / off operation that switches between a conductive state and a non-conductive state, and is realized by, for example, an IGBT (Insulated Gate Bipolar Transistors). The transistor Tr of the switching circuit 1 u is a first transistor that supplies or cuts off current from the second power supply terminal 312 to the electric motor 200.

The transistor Tr and the diode Di are connected in parallel to each other so that the direction of the current flowing through the transistor Tr is opposite to the direction of the current passing through the diode Di (forward direction). That is, the diode Di is connected in parallel to the transistor Tr, and allows current to pass from the electric motor 200 to the second power supply terminal 312.

The switching circuit 4u is a circuit that outputs a voltage supplied from the U-phase power supply line Lu to the second power supply terminal 312, and is configured by a transistor Tr and a diode Di as in the switching circuit 1u.

The transistor Tr of the switching circuit 4u is connected so that a current flows in a direction opposite to that of the transistor Tr of the switching circuit 1u. That is, the transistor Tr of the switching circuit 4 u is a second transistor that supplies or cuts off current from the electric motor 200 to the second power supply terminal 312.

Similarly to the switching circuit 1u and the switching circuit 4u, both the switching circuit 1v and the switching circuit 4v are connected to the V-phase power line Lv, and both the switching circuit 1w and the switching circuit 4w are connected to the W-phase power line Lw. The

The serial power supply connection unit 32 is a first switch unit that connects or disconnects the first power supply terminal 311 and the electric motor 200. The series power supply connection unit 32 outputs the series voltage output from the first power supply terminal 311 to the U-phase terminal 321, the V-phase terminal 322, and the W-phase terminal 323 under the switching control of the controller 50.

The serial power supply connection unit 32 includes switching

circuits

2u, 2v, and 2w. The switching

circuits

2u, 2v, and 2w are connected to U-phase, V-phase, and W-phase power supply lines Lu, Lv, and Lw, respectively, and have the same configuration as the switching circuit 1u.

Specifically, the transistors Tr of the

switching circuits

2u, 2v, and 2w supply or block current from the first power supply terminal 311 to the electric motor 200. Each diode Di is connected in parallel to the transistor Tr, and allows current to pass from the electric motor 200 to the first power supply terminal 311.

The ground power supply connection unit 33 is a third switch unit that connects or disconnects the grounded ground line Lg and the electric motor 200. The ground power supply connection unit 33 outputs the ground voltage of the ground terminal 313 to the U-phase terminal 321, the V-phase terminal 322, and the W-phase terminal 323 under the switching control of the controller 50, respectively.

The ground power supply connection unit 33 includes switching

circuits

3u, 3v, and 3w. The switching

circuits

3u, 3v, and 3w are connected to the U-phase, V-phase, and W-phase power lines Lu, Lv, and Lw, respectively, and have the same configuration as the switching circuit 1u.

The switching circuits 1u to 1w, the switching circuits 2u to 2w, the switching circuits 3u to 3w, and the transistors Tr of the switching circuits 4u to 4w are each controlled to be switched by the controller 50.

Specifically, a PWM signal (Pulse Width Modulation) for executing switching control is supplied from the controller 50 to the control terminal (gate terminal) of each transistor Tr. By this PWM signal, each of the transistors Tr is alternately switched between a conductive state (ON) and a non-conductive state (OFF).

For example, in the series power converter 30, the series voltage of the series power supply 101 is converted into a three-phase AC voltage by switching control of the series power supply connection unit 32 and the ground power supply connection unit 33. Further, the bidirectional conversion unit 31 and the ground power source connection unit 33 are subjected to switching control, whereby the voltage of the fuel cell stack 10 is converted into a three-phase AC voltage.

Further, the bidirectional conversion unit 31, the series power supply connection unit 32, and the ground power supply connection unit 33 are subjected to switching control so that the series voltage of the series power supply 101 and the voltage of the fuel cell stack 10 correspond to the induced voltage of the electric motor 200. Switched three-phase AC voltage is generated.

The first power supply capacitor 41 is connected in parallel to the first power supply and is used to adjust the electric power extracted from the first power supply. One electrode of the first power supply capacitor 41 is connected to the first power supply terminal 311, and the other electrode is connected to the second power supply terminal 312.

The second power supply capacitor 42 is connected in parallel to the second power supply and is used for adjusting the electric power extracted from the second power supply. One electrode of the second power supply capacitor 42 is connected to the second power supply terminal 312, and the other electrode is connected to the ground terminal 313.

In the system as described above, if the fuel cell stack 10 is connected to the first power supply terminal 311 of the series power supply conversion device 30 and the secondary battery 20 is connected to the second power supply terminal 312, the electric motor from the series power supply is used. When power is supplied to 200, useless switching control must be executed.

Specifically, when the vehicle accelerates, the current taken from the fuel cell stack 10 by the electric motor 200 increases, and accordingly, a large current is also taken from the secondary battery 20 connected in series to the fuel cell stack 10. Will be.

However, the secondary battery 20 is for assisting the fuel cell stack 10, and the upper limit value of the current that can be extracted from the secondary battery 20 is smaller than the upper limit value of the current that can be output from the fuel cell stack 10. . For this reason, when the power supplied from the series power supply to the electric motor 200 increases according to the driver's request, the current taken out from the secondary battery 20 exceeds the upper limit value, and the secondary battery 20 deteriorates.

As a countermeasure against this, the current in the electric motor 200 is controlled by switching the bidirectional converter 31 so that the current output from the positive electrode terminal 20A of the secondary battery 20 to the negative electrode terminal 10B of the fuel cell stack 10 does not exceed the upper limit value. Is returned to the second power supply terminal.

In order to realize such processing, it is necessary to increase the voltage of the power source, and the current flowing through the electric motor 200 increases. Therefore, the temperature of each transistor Tr constituting the series power source conversion device 30 and the electric motor Since the temperature of the motor 200 rises, it is necessary to take measures against heat. For this reason, the manufacturing cost of the serial power converter 30 increases.

Therefore, in the present embodiment, the positive terminal of the auxiliary secondary battery 20 is connected as the first power source to the first power terminal 311 of the series power converter 30, and the fuel cell stack 10 as the second power source is connected to the second power terminal 312. The positive electrode terminal and the negative electrode terminal of the secondary battery 20 were connected. That is, the series power supply 101 in which the positive electrode terminal 10 </ b> A of the fuel cell stack 10 was connected to the negative electrode terminal 20 </ b> B of the secondary battery 20 was connected in parallel to the series power supply conversion device 30.

The detailed configuration of the controller 50 that controls the series power converter 30 in such a state will be described with reference to the drawings.

The controller 50 is a control unit that controls the power supply system 100. The controller 50 is configured by a microcomputer including a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and an input / output interface (I / O interface).

The controller 50 receives detection signals from the current sensors 111 to 113, the voltage sensor 121 and the voltage sensor 122, and the current sensor 131 and the current sensor 132.

The current sensor 111 is provided on a power supply line between the positive electrode terminal 20 </ b> A of the secondary battery 20 and the first power supply terminal 311. The current sensor 111 detects the magnitude of the current taken out from the secondary battery 20. Hereinafter, the current detected by the current sensor 111 is referred to as “secondary battery current”.

The current sensor 112 is provided on a power supply line between the positive electrode terminal 10A of the fuel cell stack 10 and the anode terminal of the backflow prevention diode 11. The current sensor 112 detects the magnitude of current taken from the fuel cell stack 10. Hereinafter, the current detected by the current sensor 112 is referred to as “stack current”. The current sensor 112 constitutes a power generation detection unit that detects the power generated by the fuel cell stack 10.

The current sensor 113 is connected to a power supply line between the second power supply terminal 312 and a portion (contact point) where the negative electrode terminal 20B of the secondary battery 20 and the positive electrode terminal 10A of the fuel cell stack 10 are connected. The current sensor 113 detects the magnitude of the current output from the fuel cell stack 10 to the second power supply terminal 312.

The voltage sensor 121 is connected in parallel to the secondary battery 20 and the first power supply capacitor 41, and detects the magnitude of the voltage Vb of the secondary battery 20. Hereinafter, the voltage detected by the voltage sensor 121 is referred to as “secondary battery voltage”.

The voltage sensor 122 is connected in parallel to the fuel cell stack 10 and the second power supply capacitor 42, and detects the magnitude of the voltage Va of the fuel cell stack 10. Hereinafter, the voltage detected by the voltage sensor 122 is referred to as “stack voltage”. The voltage sensor 122 constitutes a power generation detection unit that detects the power generated by the fuel cell stack 10.

The current sensor 131 is provided on a U-phase power supply line wired from the U-phase terminal 321 to the electric motor 200. Current sensor 131 detects the magnitude of the current supplied to the U-phase power supply line of electric motor 200.

The current sensor 132 is provided on a W-phase power supply line wired from the W-phase terminal 323 to the electric motor 200. Current sensor 132 detects the magnitude of the current supplied to the W-phase power line of electric motor 200.

Further, the controller 50 receives detection signals from a position sensor 61 that detects the position of the rotor that constitutes the electric motor 200 and an accelerator opening sensor 62 that detects the opening of the accelerator pedal as an operation amount of the driver. . The position sensor 61 is composed of, for example, a rotary encoder.

The controller 50 calculates the motor rotation speed of the electric motor 200 based on the detection signal output from the position sensor 61, and is necessary for driving the electric motor 200 based on the motor rotation speed and the opening degree of the accelerator pedal. The required torque is calculated.

The controller 50 sets the operating point of the auxiliary machine 12 based on the required torque, and turns on / off each of the transistors Tr in the series power supply converter 30. That is, based on the required torque of the electric motor 200, the controller 50 alternately connects the bidirectional conversion unit 31 and the series power supply connection unit 32 and the ground power supply connection unit 33 from the cutoff state (off) to the connection state (on). Switch to.

FIG. 2 is a block diagram illustrating an example of a functional configuration of the controller 50 in the present embodiment.

The controller 50 includes a motor required torque calculation unit 510, a stack power generation control unit 520, a series power supply voltage distribution control unit 530, and a motor control unit 540.

The motor request torque calculation unit 510 calculates the motor request torque required to drive the electric motor 200 based on the motor rotation speed and the accelerator opening. The motor rotation speed is calculated based on the detection signal output from the position sensor 61. The accelerator opening is the accelerator pedal opening detected by the accelerator opening sensor 62.

The required motor torque calculation unit 510 stores in advance a required torque map in which a motor required torque is associated with each operating point of the electric motor 200. When the motor request torque calculation unit 510 acquires the motor rotation speed and the accelerator opening, the motor request torque calculation unit 510 refers to the request torque map, and requests a motor request associated with the operating point specified by the motor rotation speed and the accelerator opening. Calculate the torque.

The motor request torque calculation unit 510 outputs the calculated motor request torque T ^* to the motor control unit 540 and the stack power generation control unit 520.

The stack power generation control unit 520 calculates a target value of the current extracted from the fuel cell stack 10 based on the secondary battery information, the motor rotation speed, and the motor required torque T ^* . Hereinafter, the target value of the current taken out from the fuel cell stack 10 is referred to as “target current”.

The secondary battery information is information related to charging / discharging of the secondary battery 20, and is information output from the control device 21. The secondary battery information includes the SOC of the secondary battery 20, the charge allowable power, and the discharge allowable power.

The detailed configuration of the stack power generation control unit 520 will be described later with reference to FIG. The stack power generation control unit 520 outputs the calculated target current to the series power supply voltage distribution control unit 530.

The series power supply voltage distribution control unit 530 calculates a voltage distribution coefficient for distributing the three-phase AC voltage supplied to the electric motor 200 to the fuel cell stack 10 and the series power supply 101 based on the target current of the fuel cell stack 10. To do.

The voltage distribution coefficient of the fuel cell stack 10 here indicates the ratio of the voltage of the fuel cell stack 10 in the three-phase AC voltage supplied to the electric motor 200, and the voltage distribution coefficient of the series power supply 101 is the fuel cell stack. The ratio of the series voltage of 10 and the secondary battery 20 is shown.

In the present embodiment, the AC voltage of each phase supplied to the electric motor 200 is “1.0”, and the sum of the voltage distribution coefficient of the fuel cell stack 10 and the voltage distribution coefficient of the series power supply 101 is “1.0”. It is determined not to exceed. The voltage distribution coefficient of the fuel cell stack 10 and the voltage distribution coefficient of the series power supply 101 can each take a negative (minus) value or a positive (plus) value.

For example, when the stack current cannot be increased due to a response delay of the gas supplied to the fuel cell stack 10, the voltage distribution coefficient of the fuel cell stack 10 is set to a negative value. Thereby, it is possible to prevent the stack current from being taken out when power is supplied from the series power supply 101 to the electric motor 200.

The detailed configuration of the series power supply voltage distribution control unit 530 will be described later with reference to FIG. The series power supply voltage distribution control unit 530 outputs the voltage distribution coefficient γ _a of the fuel cell stack 10 and the voltage distribution coefficient γ _ab of the series power supply 101 to the motor control unit 540.

The motor control unit 540 performs switching control on the series power converter 30 based on the motor required torque T ^* and the voltage distribution coefficients γ _a and γ _{ab of} the fuel cell stack 10 and the series power supply 101 to control the electric motor 200. Supply phase AC voltage.

Specifically, the motor control unit 540 generates a PWM signal for performing switching control according to the motor required torque T ^* , and supplies the PWM signal to each transistor Tr in the series power converter 30. As a result, the voltage of the series power supply 101 and the voltage of the fuel cell stack 10 are switched according to the motor required torque T ^* to generate a three-phase AC voltage. The detailed configuration of the motor control unit 540 will be described later with reference to FIG.

FIG. 3 is a block diagram illustrating an example of a detailed configuration of the stack power generation control unit 520.

The stack power generation control unit 520 includes a motor request power calculation unit 521, a charge / discharge request power calculation unit 522, an addition unit 523, a stack generation power calculation unit 524, a stack output power calculation unit 525, a subtraction unit 526, A stack target current calculation unit 527. Further, the stack power generation control unit 520 includes an auxiliary machine operating point setting unit 528.

The motor required power calculator 521 drives the electric motor 200 based on the motor required torque T ^* calculated by the motor required torque calculator 510 and the motor rotation speed calculated using the position sensor 61. Calculate the required motor power requirement.

In this embodiment, a required power map in which motor required power is associated with each operating point of motor required torque and motor rotation speed is stored in advance in the motor required power calculation unit 521.

When the motor request power calculation unit 521 acquires the motor request torque T ^* and the detected motor rotation speed, the motor request power calculation unit 521 refers to the request power map and sets the operation point specified by the motor request torque T ^* and the motor rotation speed. The corresponding motor power demand is calculated. The required motor power calculation unit 521 outputs the calculated required motor power to the addition unit 523.

The required charge / discharge power calculation unit 522 calculates the required charge / discharge power of the secondary battery 20 based on the SOC, the charge allowable power, and the discharge allowable power included in the secondary battery information from the control device 21. Both the charge allowable power and the discharge allowable power are positive values.

For example, the charge / discharge required power calculation unit 522 obtains power that can be charged or discharged from the secondary battery 20 based on the SOC of the secondary battery 20, and sets the power within a range from allowable charge power to allowable discharge power. The power after limiting is calculated as the required charge / discharge power.

In the present embodiment, a secondary battery request map in which SOC and chargeable / dischargeable power are associated with each other for each temperature of the secondary battery 20 is stored in advance in the charge / discharge required power calculation unit 522. The charge / discharge required power calculation unit 522 calculates chargeable / dischargeable power with reference to the secondary battery request map specified by the temperature of the secondary battery 20. The charge / discharge required power calculation unit 522 outputs the calculated charge / discharge power to the addition unit 523.

When it is necessary to charge the secondary battery 20, the charge / discharge required power calculation unit 522 outputs positive (plus) charge / discharge required power, and when the secondary battery 20 can discharge the electric motor 200. The negative charge power is output.

The addition unit 523 calculates the required power generation required for the fuel cell stack 10 from the electric motor 200 and the secondary battery 20 by adding the required charge / discharge power to the required motor power.

When it is necessary to charge the secondary battery 20, a value obtained by adding the chargeable power to the motor required power is output from the adder 523 as the power generation required power. On the other hand, when the secondary battery 20 can be discharged to the electric motor 200, a value obtained by subtracting the electric power that can be discharged from the motor required power is output from the adding unit 523 as the power generation required power.

The stack generated power calculation unit 524 requests the fuel cell stack 10 from the auxiliary machine 12 in addition to the electric motor 200 and the secondary battery 20 by using the generated power demand and the state quantity of the auxiliary machine 12 from the control device 13. The generated power is calculated.

That is, the stack generated power calculation unit 524 constitutes a power generation calculation unit that calculates the generated power of the fuel cell stack 10 based on the required motor power required for the electric motor 200 and the required charge / discharge power of the secondary battery 20. To do.

Further, the stack generated power calculation unit 524 calculates the power consumed by the auxiliary machine 12 based on the state quantity of the auxiliary machine 12.

For example, when the cathode compressor, the cooling water pump, and the cooling water heater are connected to the fuel cell stack 10 as the auxiliary machine 12, the rotation speed and torque of the cathode compressor and the cooling water pump are input to the stack generated power calculation unit 524. Is done.

The stack generated power calculation unit 524 estimates the power consumption of the cathode compressor from the rotation speed and torque of the cathode compressor, and estimates the power consumption of the cooling water pump from the rotation speed and torque of the cooling water pump. Further, the stack generated power calculation unit 524 calculates the power consumption of the coolant heater from the target value of the power supplied to the coolant heater. The stack generated power calculation unit 524 adds the power consumption of the cathode compressor, the cooling water pump, and the cooling water heater, and calculates the total value as the power consumption of the auxiliary machine 12.

The stack generated power calculation unit 524 calculates the generated power required for the fuel cell stack 10 by adding the power consumption of the auxiliary machine 12 to the required power generation output from the adder 523. Stack generated power calculation unit 524 outputs the generated power to subtraction unit 526.

The stack output power calculation unit 525 calculates the output power output from the fuel cell stack 10 by multiplying the stack current detected by the current sensor 112 and the stack voltage detected by the voltage sensor 122. Stack generated power calculation unit 524 outputs the output power to subtraction unit 526.

The subtraction unit 526 calculates a deviation of the generated power of the fuel cell stack 10 by subtracting the output power calculated by the stack output power calculation unit 525 from the generated power calculated by the stack generated power calculation unit 524. The subtraction unit 526 outputs the deviation to the stack target current calculation unit 527.

The stack target current calculation unit 527 calculates a target current extracted from the fuel cell stack 10 based on the deviation of the generated power of the fuel cell stack 10.

The stack target current calculation unit 527 calculates the target current so that the deviation of the generated power becomes zero. For example, the stack target current calculation unit 527 increases the target current as the deviation of the generated power is larger than zero, and decreases the target current as the deviation of the generated power is smaller than zero. In this way, the stack target current calculation unit 527 performs feedback control of the target current.

The stack target current calculation unit 527 limits the target current based on the current limit value of the fuel cell stack 10. The current limit value is a predetermined value determined in order to prevent deterioration of the fuel cell.

The stack target current calculation unit 527 outputs the limited target current to the series power supply voltage distribution control unit 530. Specifically, the stack target current calculation unit 527 outputs the current limit value as the target current when the target current is larger than the current limit value, and outputs the target current when the target current is equal to or less than the current limit value. Output without limiting the current.

As described above, the stack power generation control unit 520 controls the current extracted from the fuel cell stack 10 based on the motor required torque T ^* and the secondary battery information.

The auxiliary machine operating point setting unit 528 sets the operating point of the auxiliary machine 12 based on the target current of the fuel cell stack 10.

For example, when the auxiliary machine operating point setting unit 528 acquires the target current, it refers to a predetermined map and calculates the target flow rate and the target pressure of the cathode gas associated with the target current. Then, the auxiliary machine operating point setting unit 528 calculates the opening command value of the cathode pressure regulating valve for adjusting the pressure of the cathode gas and the torque command value of the cathode compressor based on the target current and the target pressure of the cathode gas.

Similarly, the auxiliary machine operating point setting unit 528 calculates the target flow rate of the cooling water with reference to a predetermined map based on the target current of the fuel cell stack 10, and the torque of the cooling water pump from the target flow rate. Calculate the command value. The auxiliary machine operating point setting unit 528 outputs a command value for the auxiliary machine 12 such as a cathode compressor or a cooling water pump to the control device 13. The control device 13 controls the operation of the cathode compressor and the operation of the cooling water pump according to the command value.

FIG. 4 is a block diagram illustrating an example of a detailed configuration of the series power supply voltage distribution control unit 530.

The series power supply voltage distribution control unit 530 includes a subtracting unit 531, a single power distribution coefficient calculating unit 532, a distribution coefficient upper limit holding unit 533, a series power distribution coefficient calculating unit 534, a measured charge / discharge power calculating unit 535, A subtracting unit 536, a discharge allowable threshold value holding unit 537, a discharge excess determination unit 538, and a series power distribution coefficient correction unit 539 are included.

The subtracting unit 531 subtracts the stack current detected by the current sensor 112 from the target current calculated by the stack target current calculating unit 527, and uses the subtracted value as a deviation between the target current and the stack current. The result is output to the calculation unit 532.

The single power distribution coefficient calculating unit 532 calculates the voltage distribution coefficient γ _a of the fuel cell stack 10 that is a single power source based on the deviation output from the subtracting unit 531. Based on the voltage distribution coefficient γ _a , the motor control unit 540 uses the voltage of the fuel cell stack 10 to generate a part of the target voltage of each phase (first distribution voltage).

That is, the single power distribution coefficient calculation unit 532 is generated by the bidirectional conversion unit 31 and the ground power supply connection unit 33 among the phase voltages controlled by the motor control unit 540 based on the power required for the fuel cell stack 10. A first distribution voltage control unit configured to control the first distribution voltage to be generated.

The single power distribution coefficient calculation unit 532 calculates the voltage distribution coefficient γ _a of the fuel cell stack 10 based on the deviation between the target current and the stack current. For example, the single power distribution coefficient calculation unit 532 increases the rate of increase of the voltage distribution coefficient γ _a of the fuel cell stack 10 as the deviation between the target current and the stack current increases.

In other words, the single power distribution coefficient calculation unit 532 generates fuel according to the deviation between the power required for the electric motor 200 and the generated power calculated based on the charge / discharge required power and the output power detected by the current sensor 112. The first distribution voltage generated by the voltage of the battery stack 10 is increased or decreased.

In the present embodiment, the single power distribution coefficient calculation unit 532 feedback-controls the voltage distribution coefficient γ _a of the fuel cell stack 10 so that the deviation output from the subtraction unit 531 converges to zero. For example, the single power distribution coefficient calculating unit 532 increases the increase rate of the voltage distribution coefficient γ _a as the deviation output from the subtracting unit 531 is larger than zero. On the other hand, the single power distribution coefficient calculation unit 532 decreases the increase rate of the voltage distribution coefficient γ _a as the deviation output from the subtraction unit 531 decreases. The single power distribution coefficient calculation unit 532 outputs the voltage distribution coefficient γ _a of the fuel cell stack 10 to the motor control unit 540 and the series power distribution coefficient calculation unit 534.

The distribution coefficient upper limit holding unit 533 is “1” as an upper limit value for limiting the total value (γ _a + γ _ab ) of the voltage distribution coefficient γ _a of the fuel cell stack 10 and the voltage distribution coefficient γ _ab of the series power supply 101. Hold.

The series power distribution coefficient calculation unit 534 subtracts the voltage distribution coefficient γ _a of the fuel cell stack 10 from the upper limit value held in the distribution coefficient upper limit value holding unit 533, and uses the subtraction value (1-γ _a ) as the series power supply. The voltage division coefficient 101 is output to the series power distribution coefficient correction unit 539.

The measured charge / discharge power calculation unit 535 multiplies the secondary battery current detected by the current sensor 111 by the secondary battery voltage detected by the voltage sensor 121, thereby calculating the measured charge / discharge power of the secondary battery 20. Calculate. That is, the measured charge / discharge power calculation unit 535 constitutes a discharge detection unit that detects the discharge power of the secondary battery 20.

When the secondary battery 20 is charged with power, the measured charge / discharge power calculation unit 535 outputs positive (plus) measured charge / discharge power to the subtraction unit 536, and the power is discharged from the secondary battery 20. Sometimes, negative (minus) measured charge / discharge power is output to the subtractor 536.

The subtraction unit 536 calculates the excess discharge amount of the secondary battery 20 by inverting the sign of the measured charge / discharge power and subtracting the discharge allowable power from the inverted value. The discharge allowable power is a parameter acquired from the control device 21 and is a positive (plus) value.

Specifically, the subtraction unit 536 multiplies the measured charge / discharge power by “−1” so that the power at the time of discharge becomes positive, and subtracts the discharge allowable power from the multiplied value. As a result, when the measured discharge power exceeds the discharge allowable power, the excess discharge amount becomes positive.

The discharge allowable threshold holding unit 537 holds “0” as a threshold set for determining overdischarge.

The excess discharge determination unit 538 determines that the secondary battery 20 does not deteriorate when the excess discharge amount output from the subtraction unit 536 is equal to or less than the threshold value of the discharge allowable threshold value holding unit 537, and sets zero (0). The data is output to the series power distribution coefficient correction unit 539. On the other hand, the excess discharge determination unit 538 determines that the secondary battery 20 is deteriorated when the excess discharge amount is larger than the threshold, and outputs the excess discharge amount from the subtraction unit 536 to the series power distribution coefficient correction unit 539. .

When the excess discharge amount output from the excess discharge determination unit 538 is zero, the series power supply distribution coefficient correction unit 539 uses the output value (1-γ _a ) from the series power distribution coefficient calculation unit 534 as the series power supply 101. Is output to the motor control unit 540 as a voltage distribution coefficient γ _ab .

That is, the series power distribution coefficient correction unit 539 uses the series power supply connection unit 32 and the ground power supply connection unit 33 among the phase voltages controlled by the motor control unit 540 based on the voltage distribution coefficient γ _a of the fuel cell stack 10. A second distribution voltage controller that controls the generated second distribution voltage is configured.

On the other hand, when the excess discharge amount is greater than zero, the series power distribution coefficient correction unit 539 determines the voltage distribution coefficient γ of the series power supply 101 more than the output value (1-γ _a ) from the series power distribution coefficient calculation unit 534. Correct so that _ab becomes smaller.

For example, the series power distribution coefficient correction unit 539 performs feedback control on the voltage distribution coefficient γ _ab of the series power supply 101 so that the excess discharge amount converges to zero. Specifically, the series power distribution coefficient correction unit 539 makes the voltage distribution coefficient γ _ab of the series power supply 101 smaller than the output value (1−γ _a ) as the discharge excess amount increases.

That is, the series power supply distribution coefficient correction unit 539 controls the second distribution voltage so that the discharge power detected by the measured charge / discharge power calculation unit 535 does not exceed the dischargeable power of the secondary battery 20.

As described above, the series power supply voltage distribution control unit 530 increases or decreases the voltage distribution coefficient γ _a of the fuel cell stack 10 in accordance with the deviation between the stack current and the target current. At the same time, the series power supply voltage distribution control unit 530 sets the voltage distribution coefficient of the series power supply 101 so that the sum of the voltage distribution coefficient γ _a of the fuel cell stack 10 and the voltage distribution coefficient γ _ab of the series power supply 101 becomes “1”. Set γ _ab . Thereby, the fuel cell stack 10 and the secondary battery 20 can be efficiently used according to the driver request.

When the absolute value of the measured discharge power of the secondary battery 20 becomes larger than the discharge allowable power, the series power supply voltage distribution control unit 530 determines the voltage distribution coefficient γ _ab of the series power supply 101 according to the excess amount. Make it smaller. Thereby, since the electric power discharged from the secondary battery 20 is reduced, an excessive voltage drop due to the overdischarge of the secondary battery 20 can be prevented.

FIG. 5 is a block diagram illustrating an example of a detailed configuration of the motor control unit 540.

The motor control unit 540 vector-controls the electric power supplied to the electric motor 200 using the DC voltage of the fuel cell stack 10 and the secondary battery 20 based on the motor required torque T ^* . That is, the motor control unit 540 drives the electric motor 200 with high accuracy by performing feedback control of the current flowing through the coil in accordance with the rotor position of the electric motor 200.

The motor control unit 540 includes a target voltage control unit 540A, a voltage distribution calculation unit 545, a modulation factor calculation unit 546, a PWM generation unit 547, a UVW phase / dq axis converter 548, and a phase angle / angular velocity calculation unit 549. Including.

The target voltage control unit 540A constitutes a voltage control unit that controls the phase voltage supplied to the electric motor 200 based on the torque required for the electric motor 200. The target voltage control unit 540A includes a dq axis current calculation unit 541, subtracters 5411 and 5412, a dq axis current controller 542,

adders

5421 and 5422, a non-interference controller 543, and a dq axis / UVW phase conversion. Instrument 544.

First, the UVW phase / dq axis converter 548 and the phase angle / angular velocity calculation unit 549 used for feedback control will be described.

The phase angle / angular velocity calculator 549 calculates the electrical phase angle θ _e and the electrical angular velocity ω _e of the electric motor 200 based on the detection signal output from the position sensor 61.

The phase angle / angular velocity calculation unit 549 outputs the calculated electrical angular velocity ω _e to the dq axis current calculation unit 541 and the non-interference controller 543, and the electrical phase angle θ _e to the dq axis / UVW phase converter 544. And UVW phase / dq axis converter 548.

The UVW phase / dq-axis converter 548 converts the current of the U-axis, V-phase, and W-phase triaxial coordinates into the current of the d-axis and q-axis biaxial coordinates. The UVW phase / dq axis converter 548 uses the U phase measurement current i _u detected by the current sensor 131 and the W phase measurement current i _w detected by the current sensor 132 to use the U phase, the V phase, and the W phase. The W-phase current is obtained so that the sum of the currents of the phases becomes zero.

The UVW phase / dq axis converter 548 converts the U phase measurement current i _u , the V phase current, and the W phase measurement current i _w into the d axis measurement current i based on the electrical phase angle ω _e of the electric motor 200. _d and q-axis current i _q . The UVW phase / dq axis converter 548 outputs the d axis measurement current i _d to the subtractor 5411 and outputs the q axis current i _q to the subtractor 5412.

Next, dq-axis current calculation unit 541, subtracters 5411 and 5412, dq-axis current controller 542,

adders

5421 and 5422, non-interference controller 543, dq-axis / UVW phase converter 544, voltage distribution calculation unit 545, modulation The rate calculation unit 546 and the PWM generation unit 547 will be described.

The dq-axis current calculation unit 541 uses the motor request torque T ^* calculated by the motor request torque calculation unit 510 and the electrical angular velocity ω _e calculated by the phase angle / angular velocity calculation unit 549 to use the d-axis target current i. _d ^* and q-axis target current i _d ^* are calculated.

The dq-axis current calculation unit 541 outputs the d-axis target current i _d ^* to the non-interference controller 543 and the subtractor 5411, and outputs the q-axis target current i _d ^* to the non-interference controller 543 and the subtractor 5412. .

Subtractor 5411 subtracts the d-axis measured current i _d from the d-axis target current i _d ^*, it calculates the deviation between the d-axis target current i _d ^* and the d-axis measurement current i _d. The subtractor 5411 outputs the deviation to the dq axis current controller 542.

Subtractor 5412 subtracts the q-axis measured current i _q from the q-axis target current i _q ^*, and calculates the deviation between the q-axis target current i _q ^* and the q-axis measurement current i _q. The subtractor 5412 outputs the deviation to the dq axis current controller 542.

The dq-axis current controller 542 feedback-controls the d-axis target voltage and the q-axis target voltage so that both the deviation of the d-axis target current and the deviation of the q-axis target current converge to zero.

The non-interference controller 543 uses the d-axis target current i _d ^* , the q-axis target current i _q ^*, and the electrical angular velocity ω _e of the electric motor 200 to generate a component that causes the d-axis current and the q-axis current to interfere with each other. A d-axis voltage correction value and a q-axis voltage correction value for removal are calculated. The non-interference controller 543 outputs the d-axis voltage correction value to the adder 5421 and outputs the q-axis voltage correction value to the adder 5422.

The adder 5421 adds the d-axis voltage correction value to the d-axis target voltage output from the dq-axis current controller 542, thereby correcting the interference component between the d-axis current and the q-axis current. D-axis target voltage v _d is calculated. Adder 5421 outputs the d-axis target voltage v _d to dq-axis / UVW phase converter 544.

The adder 5422 adds the q-axis voltage correction value to the q-axis target voltage output from the dq-axis current controller 542, thereby correcting the interference component between the d-axis current and the q-axis current. Q-axis target voltage v _q is calculated. Adder 5422 outputs q-axis target voltage v _d to dq-axis / UVW phase converter 544.

The dq axis / UVW phase converter 544 converts the d axis target voltage v _d and the q axis target voltage v _q into a U phase target voltage v _u and a V phase target voltage v based on the electrical phase angle θ _e of the electric motor 200. _v, and to coordinate transformation to the W-phase target voltage v _w. The dq axis / UVW phase converter 544 outputs the U-phase target voltage v _u , the V-phase target voltage v _v , and the W-phase target voltage v _w to the voltage distribution calculation unit 545.

The voltage distribution calculation unit 545 is a voltage of each phase of the series power supply 101 and the fuel cell stack 10 assigned to the target voltage of each phase of the U-phase target voltage v _u , the V-phase target voltage v _v , and the W-phase target voltage v _w. Are respectively calculated.

In the present embodiment, the voltage distribution calculation unit 545 acquires a series power supply voltage distribution control unit 530 and the voltage distribution coefficient gamma _ab series power supply 101, the fuel cell stack 10 and a voltage distribution coefficient gamma _a.

Then, the voltage distribution calculation unit 545 multiplies the target voltage of each phase by the voltage distribution coefficient γ _a of the fuel cell stack 10 to thereby obtain the U-phase target distribution voltage v _ua and V-phase target distribution voltage v of the fuel cell stack 10. _va and the W-phase target distribution voltage v _wa are calculated. The voltage distribution calculation unit 545 outputs the target distribution voltage of each phase to the modulation factor calculation unit 546.

Further, the voltage distribution calculation unit 545 multiplies the target voltage of each phase by the voltage distribution coefficient γ _ab of the series power supply 101 to thereby obtain a U-phase target distribution voltage v _uab , a V-phase target distribution voltage v _vab , And the W-phase target distribution voltage v _wab is calculated. The voltage distribution calculation unit 545 outputs the target distribution voltage of each phase to the modulation factor calculation unit 546.

The modulation factor calculation unit 546 performs the switching operation of each transistor Tr in the series power converter 300 based on the target distribution voltage of each phase calculated by the voltage distribution calculation unit 545 for each of the fuel cell stack 10 and the series power supply 101. The modulation factor for determining the phase is calculated for each phase.

In the present embodiment, the modulation factor calculating unit 546, the power supplied from the fuel cell stack 10 to the U-phase of the electric motor 200, as follows, and a stack voltage V _a and the U-phase target distribution voltage v _ua ^* The U-phase modulation factor m _ua for the voltage of the fuel cell stack 10 is calculated.

Here, stack voltage V _a in the formula (3) is detected by a voltage sensor 122. Further, Offset _a, as follows, obtained using a voltage distribution coefficient of the voltage distribution coefficient gamma _ab and the fuel cell stack 10 of the series power supply 101 gamma _a.

The modulation factor calculation unit 546 calculates the V-phase modulation factor m _va by replacing the U-phase target distribution voltage v _ua ^* in the equation (3) with the V-phase target voltage v _va ^* and also in the equation (3). The W-phase modulation rate m _wa is calculated by substituting the U-phase target distribution voltage v _ua ^* for the W-phase target distribution voltage v _wa ^* . The modulation factor calculator 546 outputs the calculated U-phase modulation factor m _ua , V-phase modulation factor m _va and W-phase modulation factor m _wa to the PWM generator 547.

Further, the modulation factor calculation unit 546 uses the voltage V _ab of the series power supply 101 and the U-phase target distribution voltage v _{uab of the} series power supply 101 for the power supplied from the series power supply 101 to the U phase of the electric motor 200 as follows. ^* by using the calculated U-phase modulation factor m _uab of series power supply 101.

Here, the voltage V _ab of the series power supply 101 in the equation (5) is obtained by adding the secondary battery voltage V _a detected by the voltage sensor 121 and the stack voltage V _b detected by the voltage sensor 122. It is done. Further, Offset _ab, as follows, obtained using a voltage distribution coefficient gamma _ab series power supply 101, a voltage distribution coefficient of the series power supply 101 gamma _ab.

The modulation factor calculation unit 546 calculates the V-phase modulation factor m _vab by replacing the U-phase target distribution voltage v _uab ^* in the equation (5) with the V-phase target distribution voltage v _vab ^* and also calculates the equation (3). The U phase target distribution voltage v _uab ^* in the _middle is replaced with the W phase target distribution voltage v _wab ^* to calculate the W phase modulation factor m _wab . Then, modulation factor calculation unit 546 outputs U-phase modulation factor m _uab , V-phase modulation factor m _vab , and W-phase modulation factor m _wab for voltage V _ab of series power supply 101 to PWM generation unit 547.

The PWM generation unit 547 includes modulation rates m _uab , m _vab and m _wab for each phase regarding the voltage of the series power supply 101, and modulation rates m _ua , m _va and m _wa for each phase regarding the voltage of the fuel cell stack 10. Based on the above, a PWM signal for controlling the series power converter 30 is generated. Then, the PWM generation unit 547 supplies the generated PWM signal to the gate terminal of each transistor Tr in the series power supply converter 30.

Next, the calculation result of the target voltage and target distribution voltage of each phase calculated by the motor control unit 540 and the method of generating the PWM signal output from the motor control unit 540 will be described.

6A shows the U-phase target voltage v _u output from the dq axis / UVW phase converter 544, the U-phase target distribution voltage v _ua ^{* of the} fuel cell stack 10 output from the voltage distribution calculation unit 545, and the series power supply 101. It is a figure which shows an example with U phase target distribution voltage _vuab ^{* of} .

Here, the calculation result when electric power is supplied to the electric motor 200 using not only the fuel cell stack 10 but also the secondary battery 20 is shown.

The U-phase target distribution voltage v _ua ^* of the fuel cell stack 10 is obtained by multiplying the U-phase target voltage v _u by the voltage distribution coefficient γ _a of the fuel cell stack 10 by the voltage distribution calculation unit 545 as described in FIG. This is the value obtained. The U-phase target distribution voltage v _ua ^* of the fuel cell stack 10 corresponds to the first distribution voltage.

The U-phase target distribution voltage v _uab ^* of the series power supply 101 is obtained by multiplying the U-phase target voltage v _u by the voltage distribution coefficient γ _ab of the series power supply 101 by the voltage distribution calculation unit 545 as described in FIG. Value. Note that the U-phase target distribution voltage v _uab ^* of the series power supply 101 corresponds to the second distribution voltage.

As shown in FIG. 6A, the U-phase target voltage v _u is _{converted into} a U-phase target distribution voltage v _ua ^{* of} the fuel cell stack 10 and a U-phase target distribution voltage v _uab ^{* of the} series power supply 101 by the voltage distribution calculation unit 545. Distributed.

As described above, when the secondary battery 20 can be discharged, the voltage distribution coefficient γ _ab of the series power supply 101 is set to a positive value by the series power supply voltage distribution control unit 530. Therefore, the U-phase target distribution voltage v of the series power supply 101 is set. The phase of _uab is the same as the U-phase target voltage v _u .

FIG. 6B is a diagram illustrating an example of the U-phase target distribution voltage v _ua of the fuel cell stack 10 and the U-phase target distribution voltage v _uab ^* of the series power supply 101 when the secondary battery 20 is charged with electric power. The U-phase target voltage v _u is the same as the waveform shown in FIG. 6A.

As shown in FIG. 6B, the U-phase target distribution voltage v _ua ^* of the fuel cell stack 10 has a larger amplitude than the target voltage v _u , and the U-phase target distribution voltage v _uab ^* of the series power supply 101 is U-phase. The phase is shifted by 180 degrees with respect to the target voltage v _u .

When charging the secondary battery 20 in this way, the voltage distribution coefficient γ _ab of the series power supply 101 is set to a negative value by the series power supply voltage distribution control unit 530. Therefore, the U-phase target distribution voltage v _{uab of the} series power supply 101 is set. Is inverted with respect to the phase of the U-phase target voltage v _u .

Then, an amount corresponding to a voltage distribution coefficient gamma _ab series power supply 101 is lowered than zero, since the U-phase target distribution voltage of the fuel cell stack 10 v _ua ^* is increased, the amplitude of the U-phase target distribution voltage v _ua ^* is It becomes larger than the U-phase target voltage v _u .

6A and 6B, only the U-phase target distribution voltages v _ua ^* and v _uab ^* have been described. However, the V-phase target distribution voltages v _va ^* and v _vab ^* have the U-phase target distribution voltages v _ua ^* and The waveform has the same amplitude with respect to v _uab ^* and a phase shifted by 120 degrees. The W-phase target distribution voltages v _wa ^* and v _wab ^* have the same amplitude and a phase shifted by 240 degrees with respect to the U-phase target distribution voltages v _ua ^* and v _uab ^* .

Figure 7 is a diagram showing an example of a U-phase modulation factor m _uab the U-phase modulation index m _ua and series power supply 101 of the fuel cell stack 10 calculated by modulation factor calculating unit 546.

The U-phase modulation factor _mua for the voltage of the fuel cell stack 10 is a value obtained by performing the calculation process shown in Expression (3) by the modulation factor calculation unit 546, as described in FIG. Further, Offset _a of the U-phase modulation factor _mu is _a value obtained by performing the arithmetic processing shown in the equation (4).

The U-phase modulation factor m _uab for the voltage of the series power supply 101 is a value obtained by performing the calculation process shown in Expression (5) by the modulation factor calculation unit 546, as described in FIG. _Further , Offset _ab of the U-phase modulation factor _muab is a value obtained by performing the arithmetic processing shown in Expression (6).

Further, in FIG. 7, two triangular waves used for generating the PWM signal are indicated by a solid line and a broken line. Note that the PWM generation unit 547 includes a signal generation circuit that generates a triangular wave and a comparator that compares the triangular wave with a modulation rate.

A triangular wave indicated by a solid line is a carrier wave for generating a PWM signal supplied to each transistor Tr of the

switching circuits

1u, 1v, and 1w. Here, the triangular wave indicated by the solid line is pulse-modulated based on the U-phase modulation factor m _ua of the fuel cell stack 10.

Specifically, when the U-phase modulation factor m _ua of the fuel cell stack 10 is lower than the solid triangular wave, the transistor Tr of the switching circuit 1 u is turned on, and when the U-phase modulation factor m _ua is higher than the solid triangular wave. The transistor Tr of the switching circuit 1u is turned off.

A triangular wave indicated by a broken line is a carrier wave for generating a PWM signal supplied to the gate terminal of each transistor Tr of the

switching circuits

2u, 2v and 2w. Here, the triangular wave indicated by the broken line is pulse-modulated by the U-phase modulation factor m _uab of the series power supply 101.

Specifically, when the U-phase modulation factor m _uab of the series power supply 101 is lower than the dotted triangular wave, the transistor Tr of the switching circuit 2 u is turned on, and when the U-phase modulation factor m _uab is higher than the broken triangular wave, The transistor Tr of the switching circuit 2u is turned off.

As shown in FIG. 7, when the Offset _ab and U-phase modulation factor m _ua of Offset _a U-phase modulation factor m _uab, as shown in equation (4) and (6), obtained by adding both " 1.0 ".

If both Offset _ab and Offset _a are fixed to “−0.5” so that the value obtained by adding the U-phase modulation factor m _uab and the U-phase modulation factor m _ua does not exceed “+1”. Only 50% of the total power of the series power supply 101 can be used.

For this reason, by using the equations (4) and (6), the offset _a and the offset _ab are changed to “+1” according to the state of the series power supply 101. As a result, the output power of the series power supply 101 can be used up to 100% according to the requirements of the electric motor 200.

FIG. 8 is a diagram illustrating a method for generating a PWM signal in the PWM generation unit 547. Here, for ease of understanding, PWM signal when the U-phase variation rate m _ua series power supply 101 of the fuel cell stack 10 and a U-phase fluctuation rate m _uab constant is shown.

8 (a) is a diagram showing the two triangular wave shown in FIG. 7, the U-phase fluctuation rate m _ua of the fuel cell stack 10, the series power supply 101 and a U-phase fluctuation rate m _uab.

FIG. 8B shows a PWM signal supplied to the gate terminal of the transistor Tr of the switching circuit 1u. FIG. 8C shows a PWM signal supplied to the gate terminal of the transistor Tr of the switching circuit 2u.

FIG. 8D is a diagram showing a PWM signal supplied to the gate terminal of the transistor Tr of the switching circuit 4u. FIG. 8E shows a PWM signal supplied to the gate terminal of the transistor Tr of the switching circuit 3u.

8A to 8E, the horizontal axis of each drawing is a common time axis. Note that when an L (Low) level PWM signal is supplied to the gate terminal of the transistor Tr, the transistor Tr is turned on (ON), and an H (High) level PWM signal is supplied to the gate terminal of the transistor Tr. Then, the transistor Tr is turned off (OFF).

Prior to time t0, as shown in FIG. 8 (a), the solid triangular wave is larger than the U-phase fluctuation rate _{mua of the} fuel cell stack 10, so that as shown in FIG. 8 (b), the switching circuit 1u The PWM signal is set to L level. Further, as shown in FIG. 8 (a), since the broken-line triangular wave is smaller than the U-phase fluctuation rate _{muab of the} series power supply 101, the PWM signal of the switching circuit 2u is at the H level as shown in FIG. 8 (c). Is set to

When the time t0 has elapsed, the broken-line triangular wave becomes larger than the U-phase variation rate _{muab of the} series power supply 101 as shown in FIG. For this reason, as shown in FIG. 8C, the PWM signal of the switching circuit 2u is switched from the L level to the H level.

At this time, as shown in FIG. 8 (d), the PWM signal of the switching circuit 4u is switched from the L level to the H level. At the same time, as shown in FIGS. 8B and 8C, the PWM signal of the switching circuit 1u and the PWM signal of the switching circuit 2u are both at the L level, as shown in FIG. 8E. The PWM signal of the switching circuit 3u is switched from the L level to the H level.

When the elapsed time t1, as shown in FIG. 8 (b), since the solid line of the triangular wave is smaller than the U-phase fluctuation rate m _ua, as shown in FIG. 8 (b), PWM signal of the switching circuit 1u is L Switch from level to H level.

In order to prevent a short circuit to the ground line, when at least one of the PWM signal of the switching circuit 1u and the PWM signal of the switching circuit 2u becomes H level, the PWM signal of the switching circuit 3u changes from H level to L level. Can be switched to. That is, as shown in the following equation, when at least one of the transistor Tr of the switching circuit 1u and the transistor Tr of the switching circuit 2u is ON, the transistor Tr of the switching circuit 3u is set OFF.

Here, Tr _1u indicates the ON state of the transistor Tr in the switching circuit 1u, Tr _2u indicates the ON state of the transistor Tr in the switching circuit 2u, and Tr _3u indicates the ON state of the transistor Tr in the switching circuit 3u. .

Therefore, when the time t1 elapses, the PWM signal of the switching circuit 1u is switched to the H level, so that the PWM signal of the switching circuit 3u is switched from the H level to the L level as shown in FIG. 8 (e).

When the time t2 elapses, the solid-line triangular wave becomes larger than the U-phase fluctuation rate _mua as shown in FIG. 8A, so that the PWM signal of the switching circuit 1u is H as shown in FIG. Switch from level to L level. As a result, both the switching circuit 1u and the switching circuit 2u are turned off, and the PWM signal of the switching circuit 3u is switched to the H level as shown in FIG.

When the time t3 has elapsed, the broken-line triangular wave becomes smaller than the U-phase variation rate _muab , so that the PWM signal of the switching circuit 2u is switched to the H level as shown in FIG. At this time, in order to prevent a short circuit between the positive electrode and the negative electrode of the secondary battery 20, when the transistor Tr of the switching circuit 2u is ON as shown in the following equation, the transistor Tr of the switching circuit 4u is set OFF.

Here, Tr _4u indicates the ON state of the transistor Tr of the switching circuit 4u, and Tr _2u indicates the ON state of the transistor Tr of the switching circuit 2u.

Further, as the PWM signal of the switching circuit 2u is switched to the H level, the PWM signal of the switching circuit 3u is switched to the L level as shown in FIG. 8 (e) according to the equation (7).

When the time t4 has elapsed, the triangular wave of the broken line becomes larger than the U-phase fluctuation rate _muab , so that the PWM signal of the switching circuit 2u is switched to the L level as shown in FIG. 8C. Along with this, as shown in FIG. 8E, the PWM signal of the switching circuit 3u is switched to the H level according to the equation (7).

When the elapsed time t5, the solid line of the triangular wave is to become smaller than the U-phase fluctuation rate m _ua, as shown in FIG. 8 (b), PWM signal of the switching circuit 1u is switched to H level. Along with this, as shown in FIG. 8E, the PWM signal of the switching circuit 3u is switched from the H level to the L level according to the equation (7).

When the elapsed time t6, since the solid line of the triangular wave is larger than the U-phase fluctuation rate m _ua, as shown in FIG. 8 (b), PWM signal of the switching circuit 1u is switched from H level to L level. Accordingly, the PWM signal of the switching circuit 3u is switched from the L level to the H level as shown in FIG.

Thus, PWM generator 547 generates a PWM signal of the switching circuit 1u compared to solid carrier and the U-phase fluctuation rate m _ua, the switching circuit compared with the broken line of the carrier and the U-phase fluctuation rate m _ua A 2u PWM signal is generated.

The PWM generation unit 547 inverts the PWM signal of the switching circuit 2u according to the equation (8) to generate the PWM signal of the switching circuit 4u, and generates the PWM signal of the switching circuit 3u according to the equation (7).

Although only the method for generating the PWM signal related to the U phase of the electric motor 200 has been described with reference to FIG. 8, the PWM generation unit 547 similarly generates PWM signals for the V phase and the W phase.

FIG. 9A is a diagram illustrating the operation of the series power converter 30 when accelerating the vehicle in the present embodiment.

As shown in FIG. 9A, when the vehicle is accelerated, the discharge allowable power of the secondary battery 20 is set as the upper limit, and the power output from the series power supply 101, that is, the power of the secondary battery 20 is electrically driven by the series power converter 30. The motor 200 is discharged. At this time, the series power supply conversion device 30 functions as an inverter of the series power supply 101.

Further, the remaining power obtained by subtracting the discharge power of the secondary battery 20 from the required power of the electric motor 200 is directly output from the fuel cell stack 10 to the electric motor 200 via the second power supply terminal 312 by the series power converter 30. Is done. At this time, the series power converter 30 functions as an inverter of the fuel cell stack 10.

Therefore, the current of the electric motor 200 is returned to the negative electrode terminal of the fuel cell stack 10 as compared with the case where the fuel cell stack 10 is connected to the first power supply terminal 311 and the secondary battery 20 is connected to the second power supply terminal 312. This eliminates the need for unnecessary switching control.

Therefore, when the required power of the electric motor 200 is increased due to the driver's request, a voltage that is not defeated by the large induced power of the electric motor 200 is generated in the electric motor 200 without performing useless switching control in the series power converter 30. Supplied. For this reason, it is possible to realize the required motor torque required for acceleration while reducing unnecessary processing in the series power converter 30 when the electric motor 200 is accelerated.

FIG. 9B is a diagram illustrating the operation of the series power converter 30 when the acceleration is finished.

As shown in FIG. 9B, when the acceleration is terminated by the driver's request, the motor required torque is decreased, and the induced voltage of the electric motor 200 is decreased.

At this time, since the transient shortage of power generation in the fuel cell stack 10 has been resolved, the electric power is supplied to the electric motor 200 only by the fuel cell stack 10 by the series power converter 30. That is, the series power converter 30 functions as an inverter of the fuel cell stack 10.

Temporarily, when electric power larger than the required electric power of the electric motor 200 is output from the fuel cell stack 10, surplus electric power is charged into the secondary battery 20 by the series power supply conversion device 30.

According to this embodiment of the present invention, the power supply system 100 selects at least one single power supply from the series power supplies 101 and supplies AC power to the load. The power supply system 100 outputs power from at least one of a secondary battery 20 that charges or discharges power, a fuel cell stack 10 that is connected in series to a negative electrode terminal 20B of the secondary battery 20, and a series power supply 101. It includes a series power converter 30 that converts the generated power into AC power.

In this power supply system 100, the positive terminal 20A of the secondary battery 20 is connected to the first power terminal 311 of the series power converter 30 as the positive terminal of the series power supply 101. The positive terminal 10A of the fuel cell stack 10 is connected to the second power terminal 312 of the series power converter 30 between the positive terminal and the negative terminal of the series power supply 101 together with the negative terminal 20B of the secondary battery 20. .

As a result, when the required power of the electric motor 200 increases, the series power supply conversion device 30 does not perform a useless process of returning the current in the electric motor 200 to the series power supply 101, and the electric power from the series power supply 101. 200 can be powered.

Therefore, it is possible to reduce useless processing performed by the series power converter 30 with a simple configuration.

In this embodiment, when the required power of the electric motor 200 increases, the series power conversion device 30 and the power supplied from the series power supply 101 to the first power supply terminal 311 and the fuel cell stack 10 to the second power supply terminal 312 are used. AC power is generated using the power supplied to. Specifically, the AC power is generated by switching the voltage of the series power supply 101 and the voltage of the fuel cell stack 10 according to the motor required torque.

As a result, when the vehicle is accelerated, power that cannot be discharged from the secondary battery 20 is supplied from the fuel cell stack 10 to the electric motor 200, so that the process of returning the current is reduced and the induced voltage of the electric motor 200 is reduced. A voltage that is not lost can be secured.

Further, in order to realize the process of returning the current, the voltage of the series power supply 101 must be increased, and the current flowing through the electric motor 200 increases, so that the temperature of the series power supply conversion device 30 and the electric motor 200 increases. End up. As a result, it is necessary to increase the power supply voltage of the series power converter 30 and to take measures against heat, resulting in an increase in manufacturing cost.

For this reason, since the process which returns the electric current in the serial power converter 30 at the time of acceleration is reduced by arrange | positioning the secondary battery 20 in the upper stage of the fuel cell stack 10, it is required, suppressing the increase in manufacturing cost. The power supply voltage can be secured with the minimum configuration.

In the present embodiment, as shown in FIG. 1, the series power conversion device 30 includes a series power connection unit 32 that connects or blocks between the first power terminal 311 and the electric motor 200, and a second power terminal 312. And a bidirectional conversion unit 31 that connects or disconnects the electric motor 200 and a ground power source connection unit 33 that connects or disconnects the ground line Lg and the electric motor 200. Then, the controller 50 alternately switches the bidirectional conversion unit 31 and the ground power source connection unit 33 to the connected state based on the torque required for the electric motor 200, and in series from the bidirectional conversion unit 31 according to the increase in the required torque. The power source is switched to the power source connection unit 32.

As a result, when the induced voltage generated in the electric motor 200 increases, the voltage ratio of the series power supply 101 increases, so that it is possible to supply the electric motor 200 with a voltage that does not lose the induced voltage that increases during acceleration. .

In the present embodiment, as shown in FIG. 1, in the series power supply connection portion 32, the transistor Tr that supplies or cuts off current from the first power supply terminal 311 to the electric motor 200, and the first power supply terminal 311 from the electric motor 200. Are connected in parallel with a diode Di through which a current passes.

Further, in the bidirectional conversion unit 31, a first transistor Tr that supplies or cuts off current from the second power supply terminal 312 to the electric motor 200 and a second transistor that supplies or cuts off current from the electric motor 200 to the second power supply terminal 312. Tr is connected in series. For example, the first transistor Tr corresponds to the transistor of the switching circuit 1u, and the second transistor Tr corresponds to the transistor of the switching circuit 4u.

For this reason, as shown in FIG. 9B, the switching

circuits

1u, 1v, and 1w of the bidirectional conversion unit 31 are connected to each other from the fuel cell stack 10 via the diode Di of the series power supply connection unit 32. Electric power is supplied to the secondary battery 20. As a result, useless switching control during acceleration can be reduced, and the secondary battery 20 can be charged with the electric power of the fuel cell stack 10 as shown in FIG. 9B.

In this embodiment, the auxiliary machine 12 is connected in parallel to the fuel cell stack 10 without going through the series power supply converter 30. As a result, the power generated by the fuel cell stack 10 is supplied to the auxiliary machine 12 without going through the series power converter 30 and the electric motor 200, so that it is possible to supply power to the auxiliary machine 12 with little power loss. .

In the present embodiment, the controller 50 includes the single power distribution coefficient calculation unit 532 and the series power distribution coefficient correction unit 539 illustrated in FIG. 4 and the target voltage control unit 540A illustrated in FIG. The target voltage control unit 540A controls the phase voltage supplied to the electric motor 200, for example, the U-phase target voltage v _u ^* shown in FIG. 6A, based on the motor required torque required for the electric motor 200.

Then, the single power distribution coefficient calculation unit 532 uses the bidirectional conversion unit 31 and the ground power supply connection unit 33 among the phase voltages controlled by the target voltage control unit 540A based on the generated power required for the fuel cell stack 10. The generated first distribution voltage, for example, the U-phase target distribution voltage v _ua ^* of the fuel cell stack 10 is controlled.

Also, the series power distribution coefficient correction unit 539 generates a second distribution generated by the series power supply connection unit 32 and the ground power supply connection unit 33 among the phase voltages controlled by the target voltage control unit 540A based on the first distribution voltage. The voltage, for example, the U-phase target distribution voltage v _uab ^* of the series power supply 101 is controlled.

Thus, the series power supply conversion device 30 can assist the secondary battery 20 of the series power supply 101 with a shortage of required power of the electric motor 200 while reducing unnecessary processing during acceleration.

In the present embodiment, as described in FIG. 3, the stack generated power calculation unit 524 generates the generated power of the fuel cell stack 10 based on the required power of the electric motor 200 and the required charge / discharge power of the secondary battery 20. Is calculated.

The single power distribution coefficient calculation unit 532 increases or decreases the first distribution voltage according to the deviation between the target current calculated based on the generated power and the stack current detected by the current sensor 112. The series power distribution coefficient correction unit 539 corrects the second divided voltage according to the first distribution voltage.

Thereby, when the stack current is small with respect to the target current, the first distribution voltage increases, so the second distribution voltage decreases. On the other hand, when the stack current is larger than the target current, the first distribution voltage decreases, and therefore the second distribution voltage increases.

That is, the series power distribution coefficient correction unit 539 increases or decreases the second distribution voltage according to the deviation between the generated power calculated by the stack generated power calculation unit 524 and the generated power detected by the current sensor 112.

As a result, the electric power discharged from the secondary battery 20 is increased / decreased according to the power generation state of the fuel cell stack 10, so that the electric power is supplied from the secondary battery 20 to the electric motor 200 in accordance with the transient change in the required motor power. Can be replenished. Therefore, it is possible to satisfy both the drive request of the electric motor 200 and the power generation request of the fuel cell stack 10.

In the present embodiment, the series power distribution coefficient correction unit 539 limits the second distribution voltage so that the discharge power detected by the measured charge / discharge power calculation unit 535 does not exceed the dischargeable power of the secondary battery 20. To do. Thereby, since the overdischarge of the secondary battery 20 is suppressed, the deterioration of the secondary battery 20 can be avoided.

The embodiment of the present invention has been described above. However, the above embodiment only shows a part of application examples of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiment. Absent.

For example, in the present embodiment, the example in which the series power conversion device 30 is configured by 12 switching elements has been described, but the present invention is not limited to this. For example, you may use what comprises 24 or more switching elements.

In addition, the said embodiment can be combined suitably.

Claims

A power supply system that selects at least one power source among series power sources in which a first power source and a second power source are connected in series and supplies power to a load,
A secondary battery that charges or discharges power;
A fuel cell connected in series to the secondary battery;
Power conversion means for converting power output from at least one of the series power supplies into AC power, and
A positive terminal of the secondary battery is connected to a first power terminal of the power conversion means as a positive terminal of the series power supply;
The positive terminal of the fuel cell is connected together with the negative terminal of the secondary battery to the second power terminal of the power conversion means between the positive terminal and the negative terminal of the series power supply.
Power supply system.
The power supply system according to claim 1,
When the load increases, the power conversion means converts power supplied from the series power supply to the first power supply terminal and power supplied from the fuel cell to the second power supply terminal into AC power. To supply the load
Power supply system.
The power supply system according to claim 1 or 2,
The load is an AC motor,
The power conversion means includes
A first switch unit for connecting or blocking between the first power supply terminal and the AC motor;
A second switch unit for connecting or blocking between the second power supply terminal and the AC motor;
A third switch unit for connecting or disconnecting between the grounded grounding wire and the AC motor;
A control unit that alternately switches the first or second switch unit and the third switch unit to a connected state based on torque required for the AC motor,
Power supply system.
The power supply system according to claim 3,
The first switch unit includes:
A transistor for supplying or blocking current from the first power supply terminal to the AC motor;
A diode connected in parallel to the transistor and passing a current from the AC motor to the first power supply terminal,
The second switch unit includes:
A first transistor that supplies or cuts off current from the second power supply terminal to the AC motor;
A second transistor that supplies or cuts off current from the AC motor to the second power supply terminal,
Power supply system.
A power supply system according to any one of claims 1 to 4,
An auxiliary machine for assisting the operation of the fuel cell;
The auxiliary machine is connected in parallel to the fuel cell without going through the power conversion means,
Power supply system.
The power supply system according to claim 3 or 4,
The controller is
A voltage control unit that controls a phase voltage supplied to the AC motor based on torque required for the AC motor;
Based on the electric power required for the fuel cell, a first distribution voltage that is generated by the second switch unit and the third switch unit among the phase voltages controlled by the voltage control unit is controlled. 1 distribution voltage control unit;
Based on the first distribution voltage controlled by the first distribution voltage control unit, out of phase voltages controlled by the voltage control unit, the first switch unit and the third switch unit generate the first voltage. A second distribution voltage control unit for controlling two distribution voltages;
including,
Power supply system.
The power supply system according to claim 6,
A power generation detection unit for detecting power generated by the fuel cell;
A power generation calculation unit that calculates the generated power of the fuel cell based on the power required for the AC motor and the charge / discharge required power of the secondary battery,
The second distribution voltage control unit increases or decreases the second distribution voltage according to a deviation between the generated power calculated by the power generation calculation unit and the generated power detected by the power generation detection unit.
Power supply system.
The power supply system according to claim 6 or 7,
A discharge detector for detecting discharge power of the secondary battery;
The second distribution voltage control unit limits the second distribution voltage so that the discharge power detected by the discharge detection unit does not exceed the dischargeable power of the secondary battery.
Power supply system.
A secondary battery for charging or discharging electric power, a fuel cell connected in series to the secondary battery, and power conversion means for converting electric power output from at least one of the series power supplies into AC power A method for controlling an electric power supply system including:
Supplying the voltage of the positive terminal of the secondary battery to the first power terminal of the power conversion means as the voltage of the positive terminal of the series power supply;
Supplying the voltage of the positive terminal of the fuel cell to the second power terminal of the power conversion means between the positive terminal and the negative terminal of the series power supply;
A method for controlling an electric power supply system including: