Power supply system, control method, and program

Abstract

To more effectively and surely execute a self diagnosis of a vehicle.SOLUTION: An electric power source system of an embodiment, comprises: one or more fuel cell output portion having a fuel cell and a voltage conversion portion that converts an output voltage of the fuel cell; a voltage adjustment portion that is connected to one or more of the fuel cell in parallel with respect to a load, and includes a diode and a regenerative type DC electric power source; and a control device that controls the one or more of fuel cell output portion and the voltage adjustment portion. The control device causes the voltage adjustment portion to perform suppression control by the voltage adjustment portion in such a manner that each of voltage of the one or more fuel cell output portion becomes a target value after the activation of the fuel cell, and causes the fuel cell output portion to start electric power supply to the load from the one or more of fuel cell output portion in the case where each voltage of the one or more of fuel cell output portion becomes the target value.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a power supply system, a control method, and a program.

[0002] In recent years, research and development has been conducted on fuel cells (FCs) that contribute to energy efficiency, in order to ensure that more people have access to affordable, reliable, sustainable, and advanced energy. In FCV (Fuel Cell Vehicle) systems and the like, high output responsiveness is required for the battery to respond to transient power fluctuations while the vehicle is running. In relation to this, a technology has been known in the past that responds to transient power fluctuations by connecting a storage battery with higher responsiveness in parallel with the FC (Fuel Cell) (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-118979 Summary of the Invention [Problem to be solved by the invention]

[0004] In fuel cell technology, when an FC system is used as a stationary auxiliary / adjustable power source or a regular power source, high output response may not be required from the FC power generation unit. Therefore, when high output response is not required, there has been a desire to reduce equipment costs and size by configuring the system without a storage battery (battery-less). However, because the voltage within the system (DC bus voltage) is determined by the voltage of the storage battery, a battery-less configuration can result in uncertain voltages and an inability to supply appropriate power.

[0005] The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a power supply system, a control method, and a program that can more appropriately stabilize voltage even without a storage battery, thereby contributing to energy efficiency. [Means for solving the problem]

[0006] The power supply system, the control method, and the program according to the present invention employ the following configuration. (1): A power supply system according to one embodiment of the present invention comprises one or more fuel cell output units each having a fuel cell and a voltage conversion unit that converts the output voltage of the fuel cell; a voltage adjustment unit that is connected in parallel with the one or more fuel cells to a load and includes a diode and a regenerative DC power supply; and a control device that controls the one or more fuel cell output units and the voltage adjustment unit, wherein the control device starts the fuel cell, then causes the voltage adjustment unit to execute suppression control so that the voltage of each of the one or more fuel cell output units reaches a target value, and when the voltage of each of the one or more fuel cell output units reaches the target value, the power supply system begins supplying power from the one or more fuel cell output units to the load.

[0007] (2): In the above aspect (1), the control device controls the fuel cell to constantly supply power to the auxiliary equipment connected via the voltage adjustment unit while the power supply system is running.

[0008] (3): In the above aspect (2), the control device outputs to each of the one or more fuel cell output units a command to generate a current corresponding to a value obtained by dividing the sum of the power supplied to the load and the power supplied to the auxiliary equipment by the number of the fuel cell output units.

[0009] (4): In the above aspect (2), after starting to supply power from the one or more fuel cell output units to the load, the control device controls the power output from the one or more fuel cell output units so that the power supplied from the one or more fuel cell output units is the higher of the sum of the power supplied to the load and the power supplied to the auxiliary equipment, or the value of the waste power required for suppression control by the voltage adjustment unit.

[0010] (5): Another aspect of the present invention provides a control method for a power supply system including one or more fuel cell output units each having a fuel cell and a voltage conversion unit that converts the output voltage of the fuel cell, and a voltage adjustment unit that is connected in parallel with the one or more fuel cells to a load and includes a diode and a regenerative DC power supply, wherein one or more computers start up the fuel cell, execute suppression control by the voltage adjustment unit so that the voltage of each of the one or more fuel cell output units reaches a target value, and start supplying power from the one or more fuel cell output units to the load when the voltage of each of the one or more fuel cell output units reaches the target value.

[0011] (6): Another aspect of the present invention provides a program for a power supply system including one or more fuel cell output units each having a fuel cell and a voltage conversion unit that converts the output voltage of the fuel cell, and a voltage adjustment unit that is connected in parallel with the one or more fuel cells to a load and includes a diode and a regenerative DC power supply. The program causes one or more computers to start the fuel cell, execute suppression control using the voltage adjustment unit so that the voltage of each of the one or more fuel cell output units reaches a target value, and starts supplying power from the one or more fuel cell output units to the load when the voltage of each of the one or more fuel cell output units reaches the target value. [Effects of the Invention]

[0012] According to the above aspects (1) to (6), the voltage can be more appropriately stabilized even without a storage battery. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a diagram showing an example of the configuration of a power supply system 100 including a storage battery. [Figure 2] 1 is a diagram illustrating an example of the configuration of a battery-less power supply system 100A according to an embodiment. [Figure 3] FIG. 10 is a diagram for explaining an example of control content at the time of startup of power supply system 100A. [Figure 4] 4 is a flowchart illustrating an example of processing executed in a power supply system 100A according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of a power supply system, a control method, and a program according to the present invention will be described with reference to the drawings. Note that the following description will be given using a stationary power supply system including a FCS (Fuel Cell Stack) as an example of the power supply system.

[0015] [Power supply system with storage battery] First, before describing a power supply system having a configuration without a storage battery (storage battery-less), a power supply system having a storage battery will be described. FIG. 1 is a diagram showing an example of the configuration of a power supply system 100 having a storage battery. The power supply system 100 includes, for example, one or more FCSs 110, a storage battery 120, a BATVCU (Battery Voltage and Current Control Unit) 130, a current sensor 140, and a control device 150. FIG. 1 shows two FCSs 110-1 and 110-2 as an example of one or more FCSs. The FCSs 110-1 and 110-2 are connected in parallel to a load (e.g., a device, apparatus, or facility that consumes power) connected to an inverter 200. When there is no need to distinguish between the FCSs, they will be referred to as "FCS 110." Each FCS 110 is an example of a "fuel cell output unit." Furthermore, since the two FCSs 110 have the same configuration, the specific configuration will be described using FCS 110-1.

[0016] In the example of Fig. 1, the power supply system 100 is connected to an inverter 200. A load current I load and DC bus voltage V bus The inverter 200 converts the DC power output from the power supply system 100 into AC power, and outputs the converted AC power to a load.

[0017] The FCS 110-1 controls power generation under the control of a control device 150, which will be described later. The FCS 110-1 includes, for example, a fuel cell (FC) 112-1 and a fuel cell voltage and current control unit (FCVCU) 114-1. The FC 112-1 generates power by chemically reacting hydrogen, which is an example of a fuel, with oxygen. The FCVCU 114-1 is an example of a "voltage conversion unit." A resistor 52 and a diode 53 are connected in series to the positive electrode side of the FC 112-1. The cathode side of the diode 53 is connected to terminal A. The anode side of the diode 53 is connected to the resistor 52. The diode 54 and the reactor 55 are connected in parallel and are connected to terminals C and D, respectively. Terminal C is a terminal provided between the resistor 52 and the diode 53. Terminal D is a terminal connected to the negative electrode side of the FC 112-1. A capacitor 56 is connected to terminals E and F. Terminal E is a terminal connected to the cathode side of diode 53. Terminal F is a terminal connected to the negative electrode side of FC112-1. FCVCU114-1 receives a current command from control device 150 and controls FCS110 so that the received current I1 is output. In the following, when there is no particular distinction between FC112-1 and 112-2, they will be referred to as "FC112," and when there is no particular distinction between FCVCU114-1 and 114-2, they will be referred to as "FCVCU114." FCVCU114 is an example of a "first voltage conversion unit" that converts the output voltage of the fuel cell.

[0018] In the power supply system 100 of FIG. 1, the storage battery 120 and the BATVCU 130 are connected in series and in parallel with the FCS 110. The storage battery 120 is, for example, a lithium-ion battery or an all-solid-state battery. The storage battery 120 supplies power when connected to a load. The BATVCU 130 is connected in parallel with the FCVCU 114 to the load. Under the control of the control device 150, the BATVCU 130 converts the output voltage of the storage battery 120 into a voltage and performs power regeneration for stable supply of DC bus voltage and suppression of FC-OCV (Open Circuit Voltage) voltage. The current sensor 140 detects the load current I load Detect.

[0019] The control device 150 is realized, for example, by a hardware processor such as a CPU (Central Processing Unit) executing a program (software). Some or all of these components may be realized by hardware (including circuitry) such as an LSI (Large Scale Integration), an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a GPU (Graphics Processing Unit), or may be realized by a combination of software and hardware. The program may be stored in advance in a storage device such as an HDD or flash memory (a storage device having a non-transitory storage medium), or may be stored in a removable storage medium (a non-transitory storage medium) such as a DVD or CD-ROM, and installed by inserting the storage medium into a drive device.

[0020] The control device 150 is a management ECU (Electronic Control Unit) that controls the entire configuration of the power supply system 100. For example, the control device 150 may be configured to detect the load current I load and the DC bus voltage V bus From the load power P(=I load *V bus) and issues a current command to output a predetermined current I1 so that each FCS 110 outputs uniform power (including a predetermined tolerance). For example, if N FCSs 110 are connected in parallel, the control device 150A outputs a current command to each FCS 110 to generate a current I1 so that each FCS 110 outputs a value (P / N) obtained by dividing power P by the number N of parallel connections.

[0021] In the case of the power supply system 100 shown in FIG. 1, the DC bus voltage V bus is determined by the voltage of the storage battery 120. Therefore, when the power supply system is configured without a storage battery, the DC bus voltage V bus In some cases, the input voltage of the inverter 200 may become uncertain, causing it to deviate from a predetermined input voltage range and making it impossible to supply a stable voltage. Therefore, in the embodiment, a voltage adjustment unit that adjusts the voltage is provided instead of the storage battery 120 and the BATVCU 130, and power (auxiliary power) is constantly supplied from the FC via the voltage adjustment unit to the auxiliary equipment connected to the voltage adjustment unit, thereby stabilizing the DC bus voltage.

[0022] [Battery-less power supply system] Fig. 2 is a diagram showing an example of the configuration of a battery-less power supply system 100A according to an embodiment. Note that, hereinafter, the same components as those in the power supply system 100 shown in Fig. 1 are given the same names and symbols, and a detailed description thereof will be given later.

[0023] The power supply system 100A shown in Fig. 2 includes one or more FCSs 110, a current sensor 140, a control device 150A, and a voltage clamp circuit 160. The power supply system 100A shown in Fig. 2 differs from the power supply system 100 shown in Fig. 1 in that it includes a voltage clamp circuit 160 instead of the storage battery 120 and the BATVCU 130, and further includes a control device 150A instead of the control device 150. Therefore, the following description will mainly focus on the voltage clamp circuit 160 and the control device 150A. The voltage clamp circuit 160 is an example of a "voltage adjustment unit."

[0024] The voltage clamp circuit 160 is connected in parallel with the FCS 110. The voltage clamp circuit 160 includes, for example, a regenerative DC power supply (bidirectional power supply) 162 and a diode 164. The regenerative DC power supply 162 and the diode 164 are connected in series. One end of the regenerative DC power supply 162 is connected to the negative electrode side of the FCS 110, and the other end is connected to the cathode side of the diode 164. The anode side of the diode 164 is connected to the positive electrode side of the FCS 110, and the cathode side is connected to the regenerative DC power supply 162. The voltage clamp circuit 160 is also connected to auxiliary equipment. Here, the positive terminal of the auxiliary equipment is connected to terminal H between the regenerative DC power supply 162 and the diode 164, and the negative terminal of the auxiliary equipment is connected to the negative electrode side of the FCS 110. The auxiliary equipment is, for example, an air pump (not shown) that supplies air to the FCS 110 to adjust the temperature, an ECU (not shown) for each FCS 110, control device 150, and other equipment related to the power supply system. The auxiliary equipment may also include equipment that operates on the same voltage as the regenerative DC power supply 162, and equipment that operates on a voltage obtained by adjusting the voltage of the regenerative DC power supply 162 using a DC / DC converter. The DC / DC converter is included in the voltage clamp circuit 160, for example.

[0025] The regenerative DC power supply 162 functions as both a DC power supply and a DC electronic load. The regenerative DC power supply 162 also has the function of regenerating power to the AC power supply side when operating as an electronic load. The regenerative DC power supply 162 also includes, for example, a converter that can convert between DC and AC in both directions. Specifically, by incorporating both a bidirectional DC / DC converter and a bidirectional AC / DC converter inside, it can support both DC and AC.

[0026] Diode 164 allows a predetermined amount of electricity to flow in the forward direction (from the anode side to the cathode side) and blocks the flow of electricity in the reverse direction. By supplying power of the FC voltage to the auxiliary equipment via diode 164, stable power can be supplied to the auxiliary equipment.

[0027] The control device 150A is realized, for example, by a hardware processor such as a CPU executing a program (software). Some or all of these components may be realized by hardware (including circuitry) such as an LSI, ASIC, FPGA, or GPU, or may be realized by a combination of software and hardware. The program may be stored in advance in a storage device such as an HDD or flash memory (a storage device having a non-transitory storage medium), or may be stored in a removable storage medium (a non-transitory storage medium) such as a DVD or CD-ROM, and installed by inserting the storage medium into a drive device.

[0028] The control device 150A is a management ECU that controls the entire configuration of the power supply system 100A. For example, the control device 150 detects the load current I load and the DC bus voltage V bus From the load power P(=I load *V bus ) is calculated, and a current command is issued to output a predetermined current I1 so that each FCS 110 outputs a uniform power. bus is, for example, the forward voltage V of the diode 164 f and regenerative DC power supply voltage V ps The sum of (V bus =V f +V ps For example, when N FCSs 110 are connected in parallel, the control device 150A outputs to each FCS 110 a current command to generate a current I1 for each FCS 110 to output a value ((load+auxiliary power) / N) obtained by dividing the sum of the load power P and the auxiliary power by the number N of parallel connections.

[0029] The control device 150A also performs OCV suppression control. OCV suppression control is a control in which, for example, if the voltage of the FC 112 becomes too high, deterioration of the FC 112 progresses, and therefore, when the voltage exceeds a threshold value (OCV suppression voltage), the voltage (FC voltage) from the FC 112 is output (consumed) to prevent the voltage from exceeding the threshold value. The control device 150A acquires the voltage of the FC 110 from each of one or more FCSs 110 periodically or at a predetermined timing, and performs a determination process using the acquired FC voltage and a threshold value.

[0030] Next, the control content at the time of startup in the power supply system 100A will be described with reference to the drawings. Fig. 3 is a diagram for explaining an example of the control content at the time of startup of the power supply system 100A. In the example of Fig. 3, the horizontal axis indicates time, and the vertical axis indicates the FC voltage, the DC bus voltage V bus 3, and each power value (FC output power, load power, auxiliary power, DC power supply power) related to the power supply system 100A is shown. The FC output power is the power output from the FCS 110. The load power is the power supplied to the load. The auxiliary power is the power supplied to the auxiliary. The DC power supply power is the power output by the regenerative DC power supply 162. Each power value is managed and adjusted by the control device 150A. Also, in FIG. 3, time T0 is the earliest, followed by times T1, T2, T3, and T4 in that order.

[0031] At time T0, the control device 150A starts up the power supply system 100A and causes the FC 112 to generate power. As a result, the FC voltage increases and the DC bus voltage V bus When the FC voltage has increased to the OCV suppression voltage threshold, the power (DC power supply power) from the regenerative DC power supply 162 is supplied to the auxiliary equipment side as auxiliary equipment power.

[0032] Here, when the FC voltage reaches the OCV suppression voltage (time T1), the control device 150A starts the OCV suppression control and performs "power waste" by consuming the power of the FC 112 without supplying it to the load, auxiliary equipment, etc. In this case, the control device 150A, for example, bus (=Vf +V p ) is within the input voltage range of the inverter 200 and the FC output power is adjusted by the voltage clamp circuit 160 so that it becomes equal to the required discharge power. The required discharge power is, for example, the minimum power required when performing OCV suppression control. The required discharge power is set for each FC 112. The required discharge power is an example of a "target value." While OCV suppression control is being performed, part of the FC output power is supplied to the auxiliary equipment, and the remainder is absorbed (consumed) by the regenerative DC power supply 162. In the example of FIG. 3, the state in which power is being absorbed is indicated by a negative power value.

[0033] Next, the control device 150A completes the OCV suppression control of the FC voltage at time T2, when a predetermined time has elapsed since the start of the OCV suppression control, and starts the power supply to the load at time T3. By starting the power supply to the load after the predetermined time has elapsed, the FC voltage and the DC bus voltage V bus Both are stable and can supply power.

[0034] At time T3, when the supply of load power begins, the DC power supply power gradually increases as the load power increases, and after time T4 when the DC power supply power reaches its initial value (0 [W]), FC power control is started to increase the auxiliary equipment power and FC output power. In this case, the control device 150A controls the FC output power so that the target power is the higher of, for example, the sum of the power supplied to the load and the power supplied to the auxiliary equipment, or the value of the waste power required for OCV suppression control by the voltage clamp circuit 160. This makes it possible to supply more appropriate power while ensuring power that allows OCV suppression control.

[0035] In the example of FIG. 3, after time T4, due to an increase in the FC output power and auxiliary power, the FC voltage is consumed as shown in FIG. 2 and is reduced below the OCV suppression voltage.

[0036] In this way, even in the battery-less configuration as shown in FIG. 2, by constantly supplying power to the auxiliary equipment from the FCS 110 side via the voltage clamp circuit 160 while the power supply system 100A is running, the DC bus voltage V bus This can make the voltage more stable and can be adjusted to be within the input voltage range of the inverter 200. Furthermore, by configuring the system as shown in Fig. 2, it is possible to reduce the equipment costs for storage batteries and the like, and also to reduce the system size.

[0037] [Processing flow] Fig. 4 is a flowchart showing an example of processing executed in power supply system 100A of the embodiment. Note that the following processing will be mainly described focusing on power supply start control in control device 150A among the processing executed in power supply system 100A. The flowchart shown in Fig. 4 illustrates processing in a configuration where N (N: one or more) FCSs 110 are provided.

[0038] 4, after starting up the power supply system 100A (particularly the FC 112), the control device 150A determines whether the FC voltages of all of the N FCSs 110 are greater than the OCV suppression voltage (step S100). If it is determined that the FC voltages of all of the N FCSs 110 are greater than the OCV suppression voltage, the control device 150A causes the voltage clamp circuit 160 to start OCV suppression control (step S102). The target power in the OCV suppression control is, for example, the required waste power.

[0039] Next, the control device 150A determines whether the FC voltages in all the FCSs 110 match the OCV suppression voltage (step S104). Matching may include a predetermined tolerance that does not exceed the OCV suppression voltage. If it is determined that the FC voltages in all the FCSs 110 match the OCV suppression voltage, the control device 150A starts supplying power to the load (step S106). Next, the control device 150A starts FC power control (step S108). The target power in the processing of step S108 is the sum of the load power and the auxiliary power, or the required discharge power, whichever is higher. This ends the processing of this flowchart.

[0040] According to the embodiment described above, the system comprises one or more FCSs (an example of a fuel cell output unit) 110 having an FC (fuel cell) 112 and an FCVCU (an example of a voltage conversion unit) 114 that converts the output voltage of the fuel cell, a voltage clamp circuit (an example of a voltage adjustment unit) 160 that is connected in parallel with the one or more fuel cells to a load and includes a diode 164 and a regenerative DC power supply 162, and a control device 150 that controls the one or more FCSs 110 and the voltage clamp circuit 160.After starting the FC 112, the control device 150 executes suppression control using the voltage clamp circuit 160 so that the voltage of each of the one or more FCSs 110 reaches a target value, and when the voltage of each of the one or more FCSs 110 reaches the target value, it starts supplying power from the one or more FCSs to the load, thereby making it possible to more appropriately stabilize the voltage even without a storage battery.

[0041] Specifically, according to the embodiment, a voltage clamp circuit is configured using a regenerative DC power supply and a diode, and auxiliary power is constantly supplied from the FC via the voltage clamp circuit, thereby stabilizing the DC bus voltage. Therefore, according to the embodiment, it is possible to reduce equipment costs and system size by eliminating the need for a storage battery. Furthermore, according to the embodiment, by using auxiliary power to clamp the voltage, it is possible to efficiently stabilize the DC bus voltage, which in turn contributes to energy efficiency.

[0042] The power supply system in the embodiments may be used as an emergency power supply or for regular use. It may also be used for the purpose of auxiliary adjustment, such as supplying grid power to a load during the day and supplying power to a load at night from the power supply system in the embodiments using fuel such as hydrogen produced using surplus power during the day. The power supply system in the embodiments does not have to be a stationary type.

[0043] The above-described embodiment can be expressed as follows. In a power supply system comprising one or more fuel cell output units each having a fuel cell and a voltage conversion unit for converting an output voltage of the fuel cell, and a voltage adjustment unit connected in parallel with the one or more fuel cells to a load and including a diode and a regenerative DC power supply, the power supply system comprises: a storage medium for storing computer-readable instructions; a processor connected to the storage medium; The processor executes the computer-readable instructions to: Starting up the fuel cell; performing suppression control by the voltage adjusting unit so that the voltage of each of the one or more fuel cell output units reaches a target value; When the voltages of the one or more fuel cell output units reach the target values, the one or more fuel cell output units start supplying power to the load. Power supply system.

[0044] The above describes the form for carrying out the present invention using an embodiment, but the present invention is not limited to such an embodiment, and various modifications and substitutions can be made within the scope that does not deviate from the gist of the present invention. [Explanation of symbols]

[0045] 100, 100A... power supply system, 110... FCS, 140... current sensor, 150, 150A... control device, 160... voltage clamp circuit, 162... regenerative DC power supply, 164... diode, 200... inverter

Claims

1. one or more fuel cell output units each including a fuel cell and a voltage conversion unit that converts an output voltage of the fuel cell; a voltage regulator connected in parallel with the one or more fuel cells to a load, the voltage regulator including a diode and a regenerative DC power supply; a control device that controls the one or more fuel cell output units and the voltage adjustment unit, After starting up the fuel cell, the control device causes the voltage adjustment unit to execute suppression control so that the voltages of the one or more fuel cell output units reach their target values, and when the voltages of the one or more fuel cell output units reach their target values, starts supplying power from the one or more fuel cell output units to the load. Power supply system.

2. the control device controls the fuel cell to constantly supply power to the auxiliary equipment connected thereto via the voltage adjusting unit during startup of the power supply system. The power supply system of claim 1 .

3. the control device outputs to each of the one or more fuel cell output units a command to generate a current corresponding to a value obtained by dividing the sum of the power supplied to the load and the power supplied to the auxiliary device by the number of the fuel cell output units; The power supply system of claim 2 .

4. After starting to supply power from the one or more fuel cell output units to the load, the control device controls the power output from the one or more fuel cell output units so that the power supplied from the one or more fuel cell output units becomes the higher of a value obtained by adding the power supplied to the load and the power supplied to the auxiliary equipment, or a value of waste power required for suppression control by the voltage adjustment unit. The power supply system of claim 2 .

5. one or more fuel cell output units each including a fuel cell and a voltage conversion unit that converts an output voltage of the fuel cell; a voltage adjusting unit connected in parallel with the one or more fuel cells to a load, the voltage adjusting unit including a diode and a regenerative DC power supply, One or more computers Starting up the fuel cell; performing suppression control by the voltage adjusting unit so that the voltage of each of the one or more fuel cell output units reaches a target value; When the voltages of the one or more fuel cell output units reach the target values, the one or more fuel cell output units start supplying power to the load. Control method.

6. one or more fuel cell output units each including a fuel cell and a voltage conversion unit that converts an output voltage of the fuel cell; a voltage adjusting unit connected in parallel with the one or more fuel cells to a load, the voltage adjusting unit including a diode and a regenerative DC power supply, On one or more computers, starting the fuel cell; causing the voltage adjusting unit to perform suppression control so that the voltage of each of the one or more fuel cell output units reaches a target value; When the voltage of each of the one or more fuel cell output units reaches a target value, power supply from the one or more fuel cell output units to the load is started. program.

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