Power system and power control device

Abstract

The problem of this invention is to provide a power system and power control device that can suppress the degradation of fuel cells more effectively than before. To solve the above problem, the power system of the embodiment includes a fuel cell, a heat source, a heat dissipation unit, and a control unit. The fuel cell generates electricity through an electrochemical reaction, dissipating a first heat. The heat source dissipates a second heat due to operation. The heat dissipation unit dissipates the aforementioned first heat and the aforementioned second heat. While the heat source is operating, the control unit controls the fuel cell to keep the heat of the first heat below a heat dissipation margin, which is obtained by subtracting the heat of the second heat from the upper limit of the heat dissipation capacity of the heat dissipation unit.

Description

Technical Field

[0001] This invention relates to a power system and a power control device. Background Technology

[0002] Devices such as vehicles that have a fuel cell and operate by means of that fuel cell exist. These devices sometimes have a heat source, such as a retarder, that generates heat during operation. In such devices with a heat source, conventionally, since the fuel cell also generates heat, heat generation is suppressed by stopping the fuel cell when the heat source is running, for example, by placing it in an idle state. This is because if the heat source and the fuel cell both generate heat, there will not be enough time to dissipate it.

[0003] [Previous Technical Documents]

[0004] (Patent Documents)

[0005] Patent Document 1: Japanese Patent Publication No. 2011-503812 Summary of the Invention

[0006] [The problem the invention aims to solve]

[0007] However, if the fuel cell is stopped every time the heat source is running, the power generation of the fuel cell will vary more.

[0008] The problem to be solved by the embodiments of the present invention is to provide a power system and power control device that can suppress the degradation of fuel cells more effectively than before.

[0009] [Technical means to solve the problem]

[0010] The power system of this embodiment includes a fuel cell, a heat source, a heat dissipation unit, and a control unit. The fuel cell generates electricity through an electrochemical reaction, dissipating a first heat. The heat source dissipates a second heat due to its operation. The heat dissipation unit dissipates both the first and second heat. While the heat source is operating, the control unit controls the fuel cell to ensure that the heat from the first heat is below a heat dissipation margin, which is obtained by subtracting the heat from the second heat from the upper limit of the heat dissipation capacity of the heat dissipation unit.

[0011] (The effect of the invention)

[0012] According to the present invention, the degradation of fuel cells can be suppressed more effectively than ever before. Attached Figure Description

[0013] Figure 1 This is a block diagram illustrating an example of the main circuit structure of a vehicle according to an embodiment.

[0014] Figure 2 It is a drawing Figure 1 A block diagram illustrating an example of the main structure of the cooling section.

[0015] Figure 3 It is a drawing Figure 1 A flowchart illustrating an example of the processing performed by the processor in the control unit.

[0016] Figure 4 This is a graph illustrating an example of the time-varying states of various parts of the vehicle in an embodiment.

[0017] Figure 5 It is a graph that illustrates the changes over time in the condition of various parts of a vehicle in the past. Detailed Implementation

[0018] The power supply system of the embodiments will now be described using the accompanying drawings. Furthermore, for ease of explanation, the drawings used in the following description of the embodiments may sometimes omit structural details. Additionally, in the drawings and this specification, the same reference numerals denote the same components.

[0019] Figure 1 This is a block diagram illustrating an example of the main circuit structure of vehicle 1 in an embodiment.

[0020] Vehicle 1 is, for example, a fuel cell vehicle (FCV) that uses a fuel cell as its power source for propulsion (movement). As an example, vehicle 1 includes a control unit 100, a cooling unit 200, a power system 300, and a drive system 400. The control unit 100, cooling unit 200, and power system 300 constitute an example of an electric system mounted on vehicle 1. Furthermore, vehicle 1 is an example of an electric system.

[0021] The control unit 100 is, for example, a computer that performs calculations and controls required for the operation of the vehicle 1. The control unit 100 controls the cooling unit 200, the power system 300, and the drive system 400, etc. As an example, the control unit 100 includes a processor 101, a read-only memory (ROM) 102, a random-access memory (RAM) 103, and an auxiliary storage device 104. Furthermore, the control unit 100 is an example of an electrical control device.

[0022] The processor 101 is the central part of the control unit 100, performing various calculations and processing. The processor 101 may be, for example, a central processing unit (CPU), a microprocessor unit (MPU), a system-on-a-chip (SoC), a digital signal processor (DSP), a graphics processing unit (GPU), an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a field-programmable gate array (FPGA). Alternatively, the processor 101 may be a combination of multiple of these. The processor 101 controls each part based on programs such as firmware, system software, and application software stored in the ROM 102 or auxiliary storage device 104, in order to realize various functions of the vehicle 1. Furthermore, the processor 101 executes the processing described later based on this program. In addition, part or all of this program may be incorporated into the circuitry of the processor 101.

[0023] ROM 102 and RAM 103 are the main storage devices of the control unit 100.

[0024] ROM 102 is a non-volatile memory specifically used for reading data. ROM 102 stores, for example, firmware from the aforementioned program. Additionally, ROM 102 also stores data used by the processor 101 during various processing operations.

[0025] RAM 103 is a memory used for reading and writing data. RAM 103 is used as a working area to store data temporarily used by the processor 101 during various processing operations. RAM 103 is typically volatile memory.

[0026] The auxiliary storage device 104 is an auxiliary storage device of the control unit 100. The auxiliary storage device 104 is, for example, an electrically erasable programmable read-only memory (EEPROM), a hard disk drive (HDD), or a flash memory. The auxiliary storage device 104 stores, for example, system software and application software from the aforementioned programs. In addition, the auxiliary storage device 104 stores data used by the processor 101 during various processes, data generated by processing within the processor 101, and various setting values.

[0027] Figure 2 This is a block diagram illustrating an example of the main structure of the cooling section 200.

[0028] The cooling unit 200 is a part used to cool the various parts of the vehicle 1. As an example, the cooling unit 200 includes a cooling circuit 210, a radiator (RAD) 220, a fuel cell system (FCS) 230, a water pump (WP) 240, and a retarder (RET) 250.

[0029] Cooling circuit 210 is, for example, a fluid circuit for the circulation of a liquid such as coolant (hereinafter referred to as "coolant"). Cooling circuit 210 uses the coolant to transfer heat for cooling and warming up the fuel cell stack 233, as well as cooling the retarder 250. The coolant flows out of radiator 220, for example, and returns to radiator 220 through FCS 230 or retarder 250.

[0030] The radiator 220 cools the coolant inside by means of heat sink and fan. The cooling circuit 210 and the radiator 220 are examples of heat dissipation units that dissipate heat from the fuel cell stack 233 and the retarder 250.

[0031] The cooling section 200 has one or more FCS 230s. As an example, in... Figure 2 The diagram shows N FCS 230s, from FCS230-1 to FCS230-N. Furthermore, N is an integer greater than or equal to 1.

[0032] The FCS 230 is, for example, a power source for a fuel cell stack 233 and various devices used for its operation. The FCS 230 outputs the power from the fuel cell stack 233. This power is supplied to various parts of the vehicle 1, such as for charging the battery 302 and driving the motor 305. As an example, the FCS 230 includes a thermostat valve (WP) 231, a water pump (WP) 232, a fuel cell stack (STK) 233, and a temperature sensor 234. Furthermore, as a device for operating the fuel cell stack, the FCS 230 may also include auxiliary equipment for supplying fuel gas and oxidant gas to the fuel cell stack.

[0033] The thermostat valve 231 controls the flow of coolant within the FCS 230, allowing the coolant to flow to the outside of the FCS 230 or to the fuel cell stack 233.

[0034] Pump 232 increases the flow rate of coolant from thermostat valve 231 to fuel cell stack 233.

[0035] The fuel cell stack 233 is composed of multiple stacked fuel cells. The fuel cell stack 233 generates electricity and outputs power, for example, through an electrochemical reaction between fuel gas and oxidant gas. The generated electricity is used to drive the motor 305 and charge the battery 302. The fuel cell stack 233 generates heat during power generation and therefore requires cooling. The combined heat from one or more fuel cell stacks 233 in the vehicle 1 constitutes an example of the first type of heat.

[0036] Temperature sensor 234 measures the temperature of fuel cell stack 233. Furthermore, temperature sensor 234 outputs the temperature measurement result.

[0037] The water pump 240 increases the flow rate of coolant from the radiator 220 to the retarder 250.

[0038] The retarder 250 brakes the rotating shafts and other components of the drive system 400 by applying rotational force, thereby reducing their rotational speed. Thus, the retarder 250 can decelerate the vehicle 1. The retarder 250 generates heat during operation. Therefore, the retarder 250 is an example of a heat source. The heat dissipated by the retarder 250 as a heat source is an example of secondary heat.

[0039] return Figure 1 Explanation.

[0040] Vehicle 1 has one or more power systems 300. As an example, Figure 1 The vehicle 1 shown has two power systems 300: power system 300a and power system 300b.

[0041] Power system 300 represents a power source and the destination of the electricity output from that power source. As an example, the power source is FCS 130 and battery 302. As an example, power system 300 includes: fuel cell voltage control unit (FCVCU) 301, battery 302, battery voltage control unit (BATVCU) 303, power drive unit (PDU) 304, motor 305, auxiliary equipment 306, and FCS 230.

[0042] FCVCU 301 is, for example, a boost converter that adjusts the voltage of the power output from FCS 230 and outputs it to BATVCU 303, etc. Vehicle 1 has one FCVCU 301 relative to one FCS 230.

[0043] The storage battery 302 is a secondary battery that supplies power to various parts of the vehicle 1, such as the motor 305 and auxiliary equipment 306. The storage battery 302 is charged, for example, by the power output from the FCS 230.

[0044] BATVCU 303 is a buck-boost converter that adjusts the voltage output from battery 302 and FCVCU 301 by boosting or bucking it, and outputs it to PDU 304 and auxiliary equipment 306. Additionally, BATVCU 303 adjusts the power output from FCVCU 301 to a voltage suitable for charging battery 302 and outputs it to battery 302.

[0045] PDU 304 is an inverter that converts input power into frequency and voltage suitable for the rotational speed and torque of motor 305 and outputs it to motor 305.

[0046] Motor 305 is the motor that drives drive system 400, etc. Motor 305 can be a single motor or a motor assembly consisting of multiple motors. Motor 305 is driven, for example, by electricity output from at least one of fuel cell stack 233 and battery 302. Figure 1 In this document, motor 305 of power system 300a is referred to as motor 305a, and motor 305 of power system 300b is referred to as motor 305b. Motor 305 is an example of a load unit that operates using electricity generated by fuel cell stack 233.

[0047] The power system 300 has one or more auxiliary units 306. For example, each power system 300 may have different auxiliary units 306. Auxiliary units 306 may include, for example, power steering systems, brakes, cooling fans, water pumps, and refrigeration units. Figure 1 In this document, auxiliary unit 306 of power system 300a is referred to as auxiliary unit 306a, and auxiliary unit 306 of power system 300b is referred to as auxiliary unit 306b. As an example, power system 300a includes a power steering device, a brake, and a cooling fan as auxiliary unit 306a. Furthermore, as an example, power system 300b includes a cooling fan, a water pump, and a chiller as auxiliary unit 306b.

[0048] The drive system 400 is the part that transmits the rotational force output by the motor 305 to the drive wheel. The drive system 400 includes, for example, the motor 305, the retarder 250, gears, shafts, and drive wheels.

[0049] The following is based on Figure 3 The operation of vehicle 1 according to the embodiment will be described. Furthermore, the processing described below is an example, and various processing methods that can achieve the same result can be appropriately utilized. Figure 3 This is a flowchart illustrating an example of the processing performed by the processor 101 of the control unit 100. The processor 101 executes, for example, a program stored in the ROM 102 or auxiliary storage device 104. Figure 3 The processing. Furthermore, the units of heat described below are watts or units of the same dimension as watts.

[0050] Processor 101, for example, starts when vehicle 1 is started. Figure 3 The processing is shown.

[0051] In step ST11, processor 101 determines whether to activate retarder 250. For example, processor 101 determines to activate retarder 250 when braking vehicle 1 is required. If it is not determined that retarder 250 should be activated, processor 101 determines no in step ST11 and repeats step ST11. Conversely, if it is determined that retarder 250 should be activated, processor 101 determines yes in step ST11 and proceeds to step ST12.

[0052] In step ST12, processor 101 activates retarder 250.

[0053] In step ST13, the processor 101 acquires data for estimating the heat dissipation of the radiator 220 (hereinafter referred to as "RAD data"). The RAD data includes, for example, the fan speed of the radiator 220, the temperature of the coolant entering the radiator 220, the outside air temperature, the output of the water pump, and the speed of the vehicle 1. Furthermore, the processor 101 acquires, for example, the fan speed of the radiator 220 and the temperature of the coolant entering the radiator 220 from the radiator 220 itself. Additionally, the processor 101 acquires the outside air temperature from, for example, a temperature sensor that measures the outside air temperature. This outside air temperature can be either the air temperature outside the vehicle 1 or the temperature outside the radiator inside the vehicle 1. Furthermore, the processor 101 acquires, for example, the output of each water pump from the water pump. Additionally, the processor 101 acquires the speed of the vehicle 1 from the speedometer or the like.

[0054] In step ST14, processor 101 uses the RAD data obtained in step ST13 to estimate the estimated heat dissipation of radiator 220 (hereinafter referred to as "estimated heat dissipation value"). Therefore, processor 101 calculates the wind speed (wind speed) passing through radiator 220 based on the fan speed of radiator 220 and the speed of vehicle 1. Furthermore, processor 101 uses, for example, the wind speed, the temperature of the coolant entering radiator 220, the ambient temperature, and the water pump output to calculate the estimated heat dissipation value of radiator 220. This heat dissipation value represents the upper limit of the heat that radiator 220 can dissipate in the current environment. When the heat input to radiator 220 exceeds this upper limit, the temperature of radiator 220 and cooling circuit 210 will continue to rise, and sometimes radiator 220 and cooling circuit 210 will exceed the upper temperature limit, causing a malfunction.

[0055] In step ST15, processor 101 acquires data for estimating the heat generated by retarder 250 (hereinafter referred to as "retarder data"). The retarder data may include, for example, the temperature of retarder 250 and the ambient temperature. Alternatively, the retarder data may include a request output from retarder 250. Alternatively, the retarder data may include the speed of vehicle 1, deceleration G, and braking request. Alternatively, the retarder data may include the temperature of the coolant flowing from retarder 250. Alternatively, the retarder data may include multiple of these. Processor 101 acquires the temperature of retarder 250, for example, from retarder 250 or a temperature sensor. The temperature of retarder 250 may be, for example, the temperature of the oil inside retarder 250. Processor 101 acquires a request output, for example, from retarder 250. Deceleration G is the acceleration received by vehicle 1. Processor 101 acquires deceleration G from, for example, an accelerometer. A braking request is, for example, a request for braking intensity (braking force) based on brake opening, etc., which is based on the driver's operation of vehicle 1, etc. The processor 101 uses, for example, the brake opening to determine the braking request. The processor 101 obtains the temperature of the coolant flowing from the retarder 250 from, for example, the cooling circuit 210.

[0056] In step ST16, the processor 101 uses the retarder data obtained in step ST15 to calculate an estimated value of the heat generation of the retarder 250 (hereinafter referred to as the "estimated heat generation value").

[0057] In step ST17, processor 101 calculates an estimated value for the permissible heat output. The permissible heat output represents the heat dissipation margin of heat sink 220 and the upper limit of the heat that FCS 230 can dissipate. Processor 101 calculates the permissible heat output, for example, by subtracting the estimated heat output value obtained in step ST16 from the estimated heat dissipation value obtained in step ST14. Alternatively, processor 101 may subtract the estimated heat output value from the estimated heat dissipation value and then further subtract the margin to obtain the permissible heat output value.

[0058] In step ST18, processor 101 begins control to bring the total heat output of fuel cell stack 233 below the permissible heat output determined in step ST17. Furthermore, having initiated this control, processor 101 switches to control based on the latest permissible heat output. Processor 101 controls each FCS 230, for example, using any of the methods shown in (1) to (3) below, to bring the total heat output of fuel cell stack 233 below the permissible heat output.

[0059] Furthermore, in order to reduce the total heat generation of the fuel cell stack 233, the processor 101 needs to reduce the total output of the fuel cell stack 233. At this time, the processor 101 reduces the total output of the fuel cell stack 233 by prioritizing the shutdown (idling) of fuel cell stacks 233 with lower degradation levels. For example, the processor 101 reduces the total output of the fuel cell stack 233 by shutting down the fuel cell stacks 233 in ascending order of degradation level. For example, the operating time of the fuel cell stack 233 represents the degradation level of the fuel cell stack 233. Alternatively, the processor 101 can also reduce the total heat generation of the fuel cell stack 233 without shutting down the fuel cell stacks 233 by suppressing the output of each fuel cell stack 233.

[0060] Furthermore, in order to prioritize the shutdown of the fuel cell stack 233 with a lower degree of degradation, the processor 101 suppresses the power consumed in the same power system 300 as the fuel cell stack 233 with a lower degree of degradation. Therefore, the processor 101 may, for example, reduce the output of the motor 305 of the power system 300, while increasing the output of the motor 305 of other power systems 300.

[0061] For example, when the number of working units of the fuel cell stack 233 in the power system 300a is Na and the number of working units of the fuel cell stack 233 in the power system 300b is Nb, the processor 101 makes the output of the motor 305a approximately (Na / Nb) times the output of the motor 305b.

[0062] Alternatively, processor 101 can predict the lifespan of each component and determine the distribution of motor output 305 based on that lifespan. For example, the ratio of the output of motor 305a to the output of motor 305b is set as α:(1-α). Processor 101 estimates the lifespan of each component under each output by varying the value of α in various ways. As an example, processor 101 estimates the lifespan of each component under each output by varying the value of α in units of 0.01. The method of estimating the lifespan of components is illustrated using motor oil as an example.

[0063] To estimate the lifespan of a component, a degradation index is used, for example, to indicate the degree of deterioration. For example, the degradation index for engine oil is its viscosity. As engine oil deteriorates, its viscosity decreases; therefore, lower viscosity indicates greater deterioration. Viscosity can be represented as a function of the output of motor 305 and the operating time of motor 305. Through experiments or simulations, the relationship between the time spent by motor 305 and viscosity is determined under various output conditions when the output of motor 305 is constant. From this, a function representing the relationship between viscosity, the output of motor 305, and elapsed time can be determined. This function can be in tabular or mathematical form. An auxiliary storage device 104 stores this function. In the case of engine oil, its lifespan ends when its viscosity falls below a predetermined lower limit. Therefore, if the current degradation index and the lower or upper limit representing the lifespan of the component are known, the remaining lifespan of the component when motor 305 is running at a constant output can be determined.

[0064] The remaining lifespan of the i-th part, which is one of n parts numbered from 1 to n, is defined as Rt_i(Pw_j_i). Rt_i is a function of Pw_j_i. Pw_j_i represents the output of motor 305 that determines the remaining lifespan of the i-th part. This motor 305 is, for example, a motor 305 that uses the same power supply system as the part. Furthermore, i is an integer greater than 1 and less than n.

[0065] Furthermore, the remaining lifespan of the part group formed by merging all n parts is set as Rt_all(Pw_j). Pw_j represents the output of each of the motors 305. When the output of motor 305 is Pw_j, the output of motor 305 that shares the same power supply system as the i-th part is Pw_j_i. Furthermore, Rt_all is a function of Pw_j. In addition, Rt_all(Pw_j) can be represented by the following equation (1).

[0066] Rt_all(Pw_j)=min{i=1 to n}(Rt_i_j(Pw_j_i)) (1)

[0067] Equation (1) indicates that the remaining lifespan of the component group when each motor 305 operates at an output of Pw_j is equal to the shortest remaining lifespan among the n components operating at an output of Pw_j. The processor 101 explores the Pw_j that maximizes the remaining lifespan of the component group by calculating Rt_all(Pw_j) through various variations of Pw_j. However, the processor 101 typically performs this exploration as a discrete value for Pw_j, so it is not necessary to strictly calculate the Pw_j that maximizes the remaining lifespan of the component group. That is, the processor 101 only needs to calculate the Pw_j that maximizes the remaining lifespan of the component group among the discrete values ​​of Pw_j. Furthermore, in cases of insufficient processing time, the processor 101 can also calculate the Pw_j that maximizes the remaining lifespan of the component group that can be calculated within a given time. By calculating Pw_j in this way, the processor 101 can calculate the aforementioned α. Furthermore, when the number of motors 305 is three or more, the processor 101 can similarly calculate the output ratio of each motor 305.

[0068] Furthermore, the processor 101 can determine the outputs of the FCS 230 and the battery 302, which share the same power supply system as the motor 305, based on the output of the motor 305. For example, the processor 101 calculates the outputs of the FCS 230 and the battery 302 based on the output of the motor 305 and the state of charge (SOC) of the battery 302. The processor 101 then uses the calculated outputs of the FCS 230 to determine the remaining lifespan of the components in the FCS 230. Similarly, the processor 101 uses the calculated outputs of the battery 302 to determine the remaining lifespan of the components in the battery 302.

[0069] The degradation indices of the fuel cell stack 233 include, for example, hydrogen supply, output voltage relative to output current, or electrical power. Regarding the degradation of the fuel cell stack 233, by obtaining data on the degradation indices over time when a fixed output is continuously maintained through measurement or simulation, the degradation indices of the fuel cell stack 233 can be obtained as a function of the output and time. Using this function, it can be estimated how many hours after which the degradation indices will reach their lower limit if the fuel cell stack 233 continues to produce the currently requested output. The processor 101, for example, uses these degradation indices to determine the remaining lifetime of the fuel cell stack 233.

[0070] (1) The processor 101 calculates the permissible output based on the permissible heat generation. The permissible output represents the upper limit of the output power that keeps the heat generation of the fuel cell stack 233 below the permissible heat generation. Furthermore, if the total output power of the fuel cell stack 233 exceeds the permissible output, the processor 101 controls each FCS 230 in a manner that keeps the total output power of the fuel cell stack 233 below the permissible output. Preferably, if the total output power of the fuel cell stack 233 exceeds the permissible output, the processor 101 controls each FCS 230 in a manner that keeps the total output power of the fuel cell stack 233 above and below the permissible output by a predetermined value smaller than the permissible output. More preferably, if the total output power of the fuel cell stack 233 exceeds the permissible output, the processor 101 controls each FCS 230 in a manner that keeps the total output power of the fuel cell stack 233 at the same value as the permissible output. Furthermore, if the total output power of the fuel cell stack 233 is increased, the processor 101 controls each FCS 230 in a manner that increases the output power with the permissible output as the upper limit.

[0071] (2) The processor 101 calculates the permissible current based on the permissible heat generation. The permissible current represents the upper limit of the output current that keeps the heat generation of the fuel cell stack 233 below the permissible heat generation. Furthermore, if the total output current of the fuel cell stack 233 exceeds the permissible current, the processor 101 controls each FCS 230 to keep the total output current of the fuel cell stack 233 below the permissible current. Preferably, if the total output current of the fuel cell stack 233 exceeds the permissible current, the processor 101 controls each FCS 230 to keep the total output current of the fuel cell stack 233 above and below the permissible current by a predetermined value smaller than the permissible current. More preferably, if the total output current of the fuel cell stack 233 exceeds the permissible current, the processor 101 controls each FCS 230 to keep the total output current of the fuel cell stack 233 at the same value as the permissible current. Furthermore, if the total output current of the fuel cell stack 233 is increased, the processor 101 controls each FCS 230 to increase the output current by using the permissible current as the upper limit.

[0072] (3) The processor 101 calculates the permitted hydrogen quantity based on the permitted calorific value. The permitted hydrogen quantity represents the upper limit of hydrogen consumption per hour that keeps the calorific value of the fuel cell stack 233 below the permitted calorific value. Furthermore, if the total hourly hydrogen consumption of the fuel cell stack 233 exceeds the permitted hydrogen quantity, the processor 101 controls the total hydrogen consumption of the fuel cell stack 233 to be below the permitted hydrogen quantity. Preferably, if the total hydrogen consumption of the fuel cell stack 233 exceeds the permitted hydrogen quantity, the processor 101 controls each FCS 230 in such a way that the total hydrogen consumption of the fuel cell stack 233 is above but below the permitted hydrogen quantity. More preferably, if the total hydrogen consumption of the fuel cell stack 233 exceeds the permitted hydrogen quantity, the processor 101 controls each FCS 230 in such a way that the total hydrogen consumption of the fuel cell stack 233 is the same as the permitted hydrogen quantity. Furthermore, the processor 101 controls each FCS 230 to increase hydrogen usage by using the permitted amount of hydrogen as an upper limit when increasing the total hydrogen usage of the fuel cell stack 233.

[0073] In step ST19, processor 101 determines whether to stop retarder 250. If it is no longer necessary to brake vehicle 1, processor 101 determines that retarder 250 should be stopped. If it is not necessary to stop retarder 250, processor 101 determines no in step ST19 and proceeds to step ST20.

[0074] In step ST20, processor 101 determines whether to calculate the permissible heat output again. For example, if a predetermined time has elapsed since the last estimated value of the permissible heat output was calculated, processor 101 determines that the permissible heat output should be calculated again. Additionally, processor 101 determines that the permissible heat output should be calculated again if, for example, various values ​​representing the state of vehicle 1 or the state of the environment surrounding vehicle 1, such as the speed of vehicle 1, the gradient of the road, the acceleration of vehicle 1, the brake opening, the accelerator opening, the external air temperature, or the temperature of the fuel cell stack 233, change by a predetermined amount or fall within a predetermined range. If the permissible heat output is not calculated again, processor 101 determines no in step ST20 and returns to step ST19. Thus, processor 101 enters a standby state that repeatedly performs steps ST19 and ST20 until it determines that the retarder 250 should be stopped or that the permissible heat output should be calculated again.

[0075] If the processor 101 is in the standby state of steps ST19 and ST20 and it is determined that the permissible heat output needs to be calculated again, then the processor 101 determines this in step ST20 and returns to step ST13. Thus, the processor 101 performs the processing of steps ST13 to ST18 every predetermined time interval, or whenever various values ​​change by a predetermined amount or fall within a predetermined range.

[0076] Additionally, if the processor 101 determines that the retarder 250 should be stopped when it is in the standby state of steps ST19 and ST20, then the processor 101 determines that it is in step ST19 and proceeds to step ST21.

[0077] In step ST21, processor 101 stops retarder 250.

[0078] In step ST22, processor 101 terminates the control initiated in step ST18, which caused the total heat output of fuel cell stack 233 to fall below the permissible heat output calculated in step ST17, and returns FCS 230 to normal operation. Therefore, the upper limit of the total heat output of fuel cell stack 233 is no longer the permissible heat output. After processing in step ST22, processor 101 returns to step ST11.

[0079] If an example of the operation of vehicle 1 according to the implementation method is shown in a graph, then as Figure 4 As shown. Figure 4 This is a graph illustrating the time-varying states of various parts of vehicle 1 according to the embodiment. Additionally, when showing the operation of a conventional vehicle in a graph, such as... Figure 5 As shown. Figure 5 It is a graph that illustrates the changes over time in the condition of various parts of a vehicle in the past.

[0080] Curve G11 represents the accelerator's on and off states.

[0081] Curves G21 and 21b represent the total output of fuel cell stack 233.

[0082] Curve G22 represents the speed of the vehicle.

[0083] Curve G23 is a curve representing the elevation of the road on which vehicles travel.

[0084] Curve G24 represents the braking output of retarder 250.

[0085] Curve G31 represents the upper limit of the heat dissipation of radiator 220.

[0086] Curves G32 and G32b represent the total heat generated by adding the total heat generated by the fuel cell stack 233 to the heat generated by the retarder 250.

[0087] Curves G33 and G33b represent the total heat generation of the fuel cell stack 233.

[0088] Curves G34 and G34b represent the temperature of the coolant.

[0089] Curve G35 represents the amount of heat generated by the retarder 250.

[0090] Region AR1 represents the remaining heat dissipation capacity of radiator 220 after subtracting the total heat shown by curve G32 from the upper limit shown by curve G31.

[0091] Region AR1b represents the remaining heat dissipation capacity of radiator 220 after subtracting the total heat shown by curve G32b from the upper limit shown by curve G31.

[0092] Figure 4 and Figure 5 The graph shown illustrates a vehicle's journey in the sequence of uphill, downhill, and uphill. Before time t1, the vehicle travels on a 5% uphill slope; from time t1 to time t3, it travels on a 5% downhill slope; and after time t3, it travels on a 5% uphill slope. Furthermore, in... Figure 4 and Figure 5 In this scenario, the speed of all vehicles is fixed at 50 km / s.

[0093] exist Figure 4 and Figure 5 In the process, the accelerators are all on before time t1, off from time t1 to time t3, and on from time t3 onwards. Additionally, in Figure 4 and Figure 5 In both cases, the retarder 250 is started at time t2 and stopped at time t3. Furthermore, time t2 is the time between time t1 and time t3.

[0094] In previous vehicles, such as Figure 5 As shown in curve G33b, the output drops significantly due to the shutdown of fuel cell stack 233. In contrast, in vehicle 1 of the embodiment, as... Figure 4 As shown in curve 33, the output decrease is less compared to previous vehicles.

[0095] Therefore, as shown in regions AR1 and AR1b, the vehicle 1 of the embodiment has a relatively small margin for heat dissipation. That is, it can be seen that the vehicle 1 of the embodiment effectively utilizes its heat dissipation capacity almost without reservation.

[0096] In the embodiment of vehicle 1, when the retarder 250 is activated, a portion of the fuel cell stack 233 is stopped. Therefore, compared to conventional vehicles that completely stop the fuel cell stack 233, the fuel cell stack 233 is less prone to degradation in the embodiment of vehicle 1.

[0097] Alternatively, in the embodiment of vehicle 1, the output is reduced without stopping the fuel cell stack 233 while the retarder 250 is running. Therefore, compared with conventional vehicles that completely stop the fuel cell stack 233, the fuel cell stack 233 of the vehicle 1 of the embodiment is less prone to degradation.

[0098] In the embodiment of vehicle 1, when increasing the output of fuel cell stack 233, the output is increased in a manner that keeps the total heat generation of fuel cell stack 233 below the permissible heat generation. Therefore, vehicle 1 of this embodiment can prevent the heat input to radiator 220 from exceeding the upper limit of heat dissipation.

[0099] The vehicle 1 of the embodiment is a vehicle having a retarder 250 as a heat source. Therefore, the vehicle 1 of the embodiment is better able to prevent the degradation of the fuel cell stack 233 that occurs when the retarder 250 is present than in the past.

[0100] The vehicle 1 of the embodiment uses retarder data to estimate the heat output of the retarder 250. By using this heat output, the vehicle 1 of the embodiment can more accurately determine the remaining heat dissipation capacity of the radiator 220.

[0101] The vehicle 1 in this embodiment uses RAD data to estimate the heat dissipation of the radiator 220. By using this heat dissipation data, the vehicle 1 in this embodiment can more accurately determine the remaining heat dissipation capacity of the radiator 220.

[0102] The vehicle 1 of this embodiment prioritizes stopping the fuel cell stack 233 with a lower degree of degradation. Thus, the vehicle 1 of this embodiment can prevent the fuel cell stack 233 with a higher degree of degradation from deteriorating due to stopping.

[0103] In this embodiment, the vehicle 1 uses a power system with the same power source as the fuel cell stack 233 that is to be shut down, resulting in a lower output for the motor 305 compared to other power systems. Therefore, the motor 305 can operate normally even when the power source for the fuel cell stack 233 is shut down.

[0104] The vehicle 1 of this embodiment determines the motor output in a manner that maximizes the lifespan of the assembly of multiple parts. Thus, the vehicle 1 of this embodiment can extend the lifespan of any single part until the end of its lifespan.

[0105] The above-described embodiments can also be modified in the following ways.

[0106] The processor 101 can also obtain the heat generated by the retarder 250 measured using a temperature sensor or the like, instead of calculating the estimated heat generation value. Then, the processor 101 calculates the permissible heat generation value, for example, by subtracting the heat generation value from the estimated heat dissipation value calculated in step ST14.

[0107] The processor 101 may also obtain the current heat dissipation of the heat sink 220 instead of calculating the estimated heat output. For example, the processor 101 obtains the measured heat dissipation. Then, the processor 101 calculates the permissible heat output, for example, by subtracting the measured heat dissipation from the estimated heat dissipation value obtained in step ST14.

[0108] The vehicle 1 of the above embodiment uses cooling circuit 210 and radiator 220 to cool fuel cell stack 233 and retarder 250. However, in addition to fuel cell stack 233 and retarder 250, the vehicle of this embodiment can also use cooling circuit 210 and radiator 220 to cool devices other than retarder 250. In this case, processor 101 calculates an estimated value of the total heat generation of retarder 250 and the device, as an estimated heat generation value. Alternatively, the vehicle of this embodiment can also use cooling circuit 210 and radiator 220 to cool devices other than fuel cell stack 233 and retarder 250. In this case, processor 101 calculates an estimated value of the heat generation of the device, as an estimated heat generation value. The device being cooled by cooling circuit 210 and radiator 220 is an example of a heat source.

[0109] The vehicle 1 described above uses a water-cooling method, employing a cooling circuit 210 and a radiator 220 to cool the fuel cell stack 233 and the retarder 250 with liquid. However, the vehicle in this embodiment can also be cooled using methods other than water cooling, such as air cooling. Vehicles using air cooling methods, for example, use radiator fins and cooling fans for cooling. Radiator fins and cooling fans are examples of heat dissipation components.

[0110] In the above embodiments, a vehicle was used as an example for explanation. However, the power system of the embodiments can also be applied to fuel cell-powered vehicles or drones other than vehicles. For example, the power system of the embodiments can be applied to fuel cell-powered aircraft, ships, submarines, or railway vehicles.

[0111] In addition, the power system described in the implementation can also be applied to stationary systems such as power generation facilities or cogeneration systems, or to vehicles other than drones such as robots.

[0112] The processor 101 can also utilize the hardware configuration of the circuit to implement part or all of the processing implemented by the program in the above embodiments.

[0113] The program that implements the processing of the implementation method can be transferred, for example, in a state where it is stored in the device. However, the device can also be transferred without the program being stored there. Then, the program can be transferred separately and written to the device. In this case, the program transfer can be achieved, for example, by recording it in a removable storage medium or by downloading it via a network such as the Internet or a local area network (LAN).

[0114] The embodiments of the present invention have been described above, but are shown as examples and are not intended to limit the scope of the invention. The embodiments of the present invention can be implemented in various forms without departing from the spirit of the invention.

[0115] Figure Labels

[0116] 1: Vehicle

[0117] 100: Control Department

[0118] 101: Processor

[0119] 102: ROM

[0120] 103: RAM

[0121] 104: Auxiliary storage device

[0122] 200: Cooling section

[0123] 210: Cooling circuit

[0124] 220: Radiator

[0125] 230: FCS

[0126] 231: Thermostat valve

[0127] 232, 240: Water pumps

[0128] 233: Fuel Cell Stack

[0129] 234: Temperature sensor

[0130] 250: Retarder

[0131] 300a, 300b: Power supply system

[0132] 301: FCVCU

[0133] 302: Storage battery

[0134] 303: BATVCU

[0135] 304: PDU

[0136] 305a, 305b: Motor

[0137] 306a, 306b: Auxiliary machines

[0138] 400: Drive System

Claims

1. An electric power system, comprising: Fuel cells generate electricity through electrochemical reactions, releasing heat in the process. The retarder acts as a heat source that dissipates secondary heat during operation; The heat dissipation unit dissipates the aforementioned first heat and the aforementioned second heat; and, The control unit, while the aforementioned heat source is operating, performs control to reduce the output without stopping the aforementioned fuel cell, so that the heat of the aforementioned first heat source is below the heat dissipation margin, which is obtained by subtracting the heat of the aforementioned second heat source from the upper limit of the heat dissipation capacity of the aforementioned heat dissipation unit.

2. The power system according to claim 1, wherein, The aforementioned control unit increases the output of the aforementioned fuel cell so that the heat generated by the aforementioned first heat source is below the aforementioned heat dissipation capacity.

3. The power system according to claim 1, wherein, The aforementioned power system is mounted on the vehicle.

4. The power system according to claim 3, wherein, The heat of the second heat is calculated based on at least one of the following: the temperature of the aforementioned retarder and the external air temperature, the requested output of the aforementioned retarder, the temperature of the coolant flowing out of the aforementioned retarder, or the speed, acceleration and braking request of the aforementioned vehicle.

5. The power system according to claim 1, wherein, The aforementioned heat dissipation unit includes a radiator, and the power system calculates the aforementioned upper limit based on the wind speed passing through the aforementioned radiator, the temperature of the coolant flowing into the aforementioned radiator, the external air temperature, and the output of the water pump that accelerates the aforementioned coolant.

6. The power system according to claim 1, wherein, Including several of the aforementioned fuel cells, The aforementioned first heat is the combined heat emitted by multiple aforementioned fuel cells. The aforementioned control unit prioritizes reducing the output of the aforementioned fuel cell with a lower degree of degradation, thereby keeping the heat generated by the aforementioned first heat below the aforementioned heat dissipation capacity.

7. The power system according to claim 6, wherein, It also includes multiple load units, which operate using the electricity generated by the aforementioned fuel cell. The aforementioned control unit makes the output of the aforementioned load unit, which is the same power system as the aforementioned fuel cell whose output is to be reduced, less than the output of the aforementioned load unit of other power systems.

8. The power system according to claim 1, wherein, It also includes multiple load units, which operate using the electricity generated by the aforementioned fuel cell. The aforementioned control unit determines the output of the aforementioned load unit in a manner that maximizes the remaining lifespan of the component group obtained by merging multiple components.

9. An electrical control device, comprising a control unit that, while a retarder, which is a heat source emitting a second heat during operation, is running, controls the output to be reduced without stopping the fuel cell, so that the heat emitted by the fuel cell, which generates electricity through an electrochemical reaction, is below a heat dissipation margin, the heat dissipation margin being obtained by subtracting the heat of the second heat from the upper limit of the heat dissipation amount of the heat dissipation unit that dissipates the first heat and the second heat.

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