Fuel cell system

Abstract

The objective is to provide a fuel cell system that can ensure opportunities for restarting while preventing the system from transitioning to evasive driving control as much as possible. [Solution] The fuel cell system is a fuel cell system for driving a vehicle's drive motor, comprising a plurality of fuel cell modules that supply power to the drive motor, each of the plurality of fuel cell modules that supply power to the drive motor having a fuel cell stack and a compressor that supplies air to the fuel cell stack, and comprising a control unit that, when a step loss is detected in any of the compressors, increases the amount of power supplied to the drive motor to the other fuel cell modules among the plurality of fuel cell modules that have compressors that have not been detected as step loss, and performs normal recovery control for the compressor that has been detected as step loss.

Description

Technical Field

[0001] The present invention relates to a fuel cell system.

Background Art

[0002] An electric vehicle (EV) driven by power supplied from a fuel cell is becoming popular. Air is supplied to the fuel cell stack of the fuel cell by a compressor, and a control device monitors whether air is being normally supplied from the compressor. For example, according to Patent Document 1, it is detected whether freezing has occurred between the motor rotating shaft of the compressor and the air bearing that supports the motor rotating shaft.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] For example, when a malfunction of the compressor is detected during the running of an electric vehicle (hereinafter simply referred to as "vehicle"), the period for shifting to the retreat running control is short, and the opportunity to execute the re-driving control for operating the compressor normally is limited. When the retreat running control is performed, it takes time for repair or the like until recovery, which particularly causes a decrease in the operation rate for commercial vehicles and has an adverse effect on profitability.

[0005] The present invention has been made to solve such problems, and provides a fuel cell system that can prevent shifting to the retreat running control as much as possible and ensure an opportunity to execute the re-driving control.

Means for Solving the Problems

[0006] A specific embodiment of the present invention provides a fuel cell system for driving a vehicle drive motor, comprising a plurality of fuel cell modules that supply power to the drive motor, each of which has a fuel cell stack and a compressor that supplies air to the fuel cell stack, and a control unit that, when a step loss is detected in any of the compressors, increases the amount of power supplied to the drive motor in the other fuel cell modules that have compressors that have not been detected as step loss, and performs normal recovery control for the compressor that has been detected as step loss. [Effects of the Invention]

[0007] The present invention provides a fuel cell system that can ensure opportunities for restart control while preventing the system from transitioning to evasive driving control as much as possible. [Brief explanation of the drawing]

[0008] [Figure 1] This is an overall configuration diagram of the fuel cell system according to this embodiment. [Figure 2] This is a flowchart showing the processing flow related to the compressor step-out detection process. [Modes for carrying out the invention]

[0009] The present invention will be described below through embodiments, but the claims are not limited to the following embodiments. Furthermore, not all of the configurations described in the embodiments are necessarily essential for solving the problem.

[0010] Figure 1 is an overall configuration diagram of the fuel cell system 10 according to this embodiment. The fuel cell system 10 mainly consists of a first FC module 100 and a second FC module 200, each of which generates power independently, an ECU (Engine Control Unit) 300 as a control unit that comprehensively controls the entire fuel cell system 10, a drive motor 400 that drives the vehicle, and a secondary battery 500 that supplies auxiliary power and recovers regenerative energy.

[0011] The first FC module 100 and the second FC module 200 are connected in parallel to the drive motor 400 and each generates electricity according to the control of the ECU 300, supplying power to the drive motor 400. The first FC module 100 mainly consists of a fuel cell stack 101, a boost converter (FDC) 102, an inlet sealing valve 103, a pressure regulating valve 104, a flow diversion valve 105, an intercooler 106, an air cleaner 107, a compressor 108, a motor 109, an inverter 110, and a muffler 111. The compressor 108 outputs air taken in from the air cleaner 107 toward the fuel cell stack 101, using the rotational force of the motor 109, which rotates with synchronous current rectified by the inverter 110. The rotating shaft of the motor 109 is supported by an air bearing, and the ECU 300 detects a loss of synchronism in the compressor 108 by monitoring the rotational state of the rotating shaft.

[0012] The air output from the compressor 108 is cooled by the intercooler 106, pressure-regulated by the inlet sealing valve 103 and the flow diversion valve 105, and supplied to the fuel cell stack 101. The ECU 300 adjusts the amount of power generated by the fuel cell by adjusting the inlet sealing valve 103, the flow diversion valve 105, and a fuel supply valve (not shown) that supplies fuel from the fuel tank to the fuel cell stack 101. Water vapor and other substances discharged from the fuel cell stack 101 are pressure-regulated by the pressure regulating valve 104 and released to the outside through the muffler 111.

[0013] The electricity generated by the fuel cell stack 101 is boosted by the boost converter 102 and supplied to the drive motor 400. Sensors are provided at various locations to ensure the first FC module 100 operates correctly. For example, a supply air temperature sensor 112 and a pressure sensor 113 are provided between the inlet sealing valve 103 and the intercooler 106, and an intake air temperature sensor 114 and an airflow meter 115 are provided between the air cleaner 107 and the compressor 108.

[0014] The second FC module 200 has the same configuration as the first FC module 100. The second FC module 200 mainly consists of a fuel cell stack 201, a boost converter (FDC) 202, an inlet sealing valve 203, a pressure regulating valve 204, a flow diversion valve 205, an intercooler 206, an air cleaner 207, a compressor 208, a motor 209, an inverter 210, and a muffler 211. The compressor 208 outputs air taken in from the air cleaner 207 toward the fuel cell stack 201 using the rotational force of the motor 209, which rotates with synchronous current rectified by the inverter 210. The rotating shaft of the motor 209 is supported by an air bearing, and the ECU 300 detects a loss of synchronism in the compressor 208 by monitoring the rotational state of the rotating shaft.

[0015] The air output from the compressor 208 is cooled by the intercooler 206, pressure-regulated by the inlet sealing valve 203 and the flow diversion valve 205, and supplied to the fuel cell stack 201. The ECU 300 adjusts the amount of power generated by the fuel cell by adjusting the inlet sealing valve 203, the flow diversion valve 205, and a fuel supply valve (not shown) that supplies fuel from the fuel tank to the fuel cell stack 201. Water vapor and other substances discharged from the fuel cell stack 201 are pressure-regulated by the pressure regulating valve 204 and released to the outside through the muffler 211.

[0016] The electricity generated by the fuel cell stack 201 is boosted by the boost converter 202 and supplied to the drive motor 400. Sensors are provided at various points to ensure the proper operation of the second FC module 200. For example, a supply air temperature sensor 212 and a pressure sensor 213 are provided between the inlet sealing valve 203 and the intercooler 206, and an intake air temperature sensor 214 and an airflow meter 215 are provided between the air cleaner 207 and the compressor 208.

[0017] Figure 2 is a flowchart showing the processing flow for the step-out detection process of compressors 108 and 208. The illustrated flow is executed according to a predetermined period.

[0018] In step S101, the ECU 300 acquires the rotational status of the rotating shafts of motors 109 and 209 and checks whether they are out of step. If it is confirmed that neither is out of step, the flow ends and waits until the next execution cycle. If out of step is detected in either motor, the process proceeds to step S102, and the ECU 300 stops power generation in the FC module including the compressor that was out of step. Specifically, it shuts off the fuel supply and air supply to the fuel cell stack of the FC module in question.

[0019] In the following step S103, the ECU300 initiates restart control of the compressor that has detected a step loss. Specifically, the restart control checks the rotational speed of the rotating shaft at the time of step loss detection. If the rotational speed is below a specified value, it performs a stop control to reset and restarts the current synchronization control. On the other hand, if the rotational speed of the rotating shaft is above the specified value, it directly adjusts the current synchronization and attempts to increase the rotational speed.

[0020] The ECU 300 proceeds to step S105 to check whether the FC module with a normal compressor can meet the doubled power supply requirement. That is, it checks whether the FC module including the compressor with the detected out-of-sync condition can cover the insufficient power supply caused by the power generation stop of the compressor with the detected out-of-sync condition using the FC module with a normal compressor. If it is determined that the requirement can be met, it proceeds to step S105. The ECU 300 controls the fuel supply and air supply to the fuel cell stack so that the power generation amount of the FC module including the normal compressor doubles and proceeds to step S107. If it is determined in step S104 that the requirement cannot be met, it proceeds to step S106. The ECU 300 controls the fuel supply and air supply to the fuel cell stack so that the power generation amount of the FC module including the normal compressor is maximized and proceeds to step S107.

[0021] In step S107, the ECU 300 acquires again the rotation state of the rotating shaft of the compressor with the detected out-of-sync condition and checks whether the rotating shaft is rotating normally after getting out of the out-of-sync state. If the out-of-sync state continues, it proceeds to step S108 to check whether the specified time has elapsed since the out-of-sync condition was detected. If not, it returns to step S107 and waits for recovery to the normal state. On the other hand, if the specified time has elapsed, it abandons the recovery control and executes the contrast running control to safely stop the vehicle, ending a series of processes.

[0022] If it is confirmed in step S107 that the normal state has been restored, it proceeds to step S110. The ECU 300 returns each FC module to the normal power generation operation and waits until the next execution cycle.

[0023] By executing the processing related to such out-of-sync detection, the opportunity to execute the re-driving control can be increased, and it is possible to prevent shifting to the avoidance running control as much as possible. Also, it can smoothly return to normal driving.

[0024] In this embodiment, a fuel cell system 10 equipped with two FC modules in parallel has been described, but a fuel cell system equipped with three or more FC modules may also be used. For example, if a compressor failure is detected in one of the three FC modules, the ECU can control each of the remaining two FC modules to generate 3 / 2 times the normal amount of power. [Explanation of Symbols]

[0025] 10...Fuel cell system, 100...First FC module, 101...Fuel cell stack, 102...Boost converter, 103...Inlet sealing valve, 104...Pressure regulating valve, 105...Flow diversion valve, 106...Intercooler, 107...Air cleaner, 108...Compressor, 109...Motor, 110...Inverter, 111...Muffler, 112...Supply air temperature sensor, 113...Pressure sensor, 114...Intake air temperature sensor, 115...Airflow meter, 200...Second F C module, 201…Fuel cell stack, 202…Boost converter, 203…Inlet sealing valve, 204…Pressure regulating valve, 205…Flow diversion valve, 206…Intercooler, 207…Air cleaner, 208…Compressor, 209…Motor, 210…Inverter, 211…Muffler, 212…Supply air temperature sensor, 213…Pressure sensor, 214…Intake air temperature sensor, 215…Airflow meter, 300…ECU, 400…Drive motor, 500…Secondary battery

Claims

[Claim 1] A fuel cell system for driving a vehicle's drive motor, The system comprises a plurality of fuel cell modules that supply power to the drive motor, and each of the plurality of fuel cell modules that supply power to the drive motor has a fuel cell stack and a compressor that supplies air to the fuel cell stack. When a step loss is detected in any of the compressors, the control unit increases the power supply to the drive motor of the other fuel cell modules among the plurality of fuel cell modules that have a compressor that has not been detected as having a step loss, and performs control to restore the compressor that has been detected as having a step loss to normal operation. A fuel cell system equipped with the following features.

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