Internal Power Supply Module IPM

An internal power supply module provides the power needed by certain components within a fuel cell system. The components include sensors, control boards, pumps, fans, blowers, compressors, solenoid valves, contactors, switches, and so on. The IPM also provides the power to start the fuel cell system and helps carry some load when the fuel cell stack is inadequate to handle a sudden load jump. There are many types of sensors in a fuel cell system, such as the H2 concentration sensors, the H2 pressure sensors, the fluid flow rate sensors, the coolant-level sensors, the temperature sensors, the current sensors, the voltage sensors, the door-open sensors, the vibration sensors, and the flooding sensors. These sensors monitor the corresponding parameters to indicate the situation of the entire fuel cell system. The control boards may include a main board for controlling the system and several sub-boards for controlling various modules discussed in this chapter. Pumps, fans, blowers, compressors, solenoid valves, contactors, and switches all require power to perform the corresponding functions. 

The batteries and/or supercapacitors should be able to provide enough power for both the load and the fuel cell system s internal power needs at the moment that the grid power is down. This requires them to have enough 

During the start-up of a fuel cell system, the batteries provide all the power needs only for a few seconds. Afterward, the fuel cell stack begins supplying some power, and the output power from the batteries reduces correspondingly. With time, the stack supplies more and more power and the batteries supply less and less power, and finally, all the power is supplied by the stack. The duration of the load-sharing process by the stack and the battery depends on the discharging capacity of the batteries, the output voltage setup of the DC-DC converter, and how fast the stack can reach its nominal power output. For an air-cooled stack, the stack can reach the nominal power output in about 1 minute. For a liquid-cooled stack, the stack can reach the nominal power output in less than 5-10 minutes. But this does not necessarily mean that the load will be fully powered by an air-cooled stack within 1 minute, because the 

Components such as sensors, control boards, pumps, fans, blowers, compressors, solenoid valves, and switches very often need DC power at different input voltages. Some need 5 V, some need 12 V, and some may need 24 or 48 V. If the needed DC voltage is around that from the fuel cell system s main DC-DC converter, the latter can supply the DC power to the components directly. Otherwise, the voltage from the main DC-DC converter has to be converted to the desired DC voltages by additional DC-EXZ converters. Those additional DC-DC converters are normally much smaller than the main DC-DC converter. The output voltage setup of the system s main DC-DC converter is based on the ne of the external load. 

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