Design Of An Inverter Module Of The AC Current Signal Excitation Source For Fuel Cell Impedance Monitoring

Fuel cell had already draw worldwide attention as a way to make use of the energy of hydrogen which is clean and green. In the fuel cell system, people checked the parameters of fuel cell resistance to test if each piece of the fuel cells was working properly. So it needed to design a real-time online testing of fuel cell resistance test system. The test system send several AC excitation current sign with the different frequency and different amplitude to the internal resistance, and detected the feedback response to realize the test. Therefore, it needed to equip with an AC current signal excitation source with the continuous variable frequency and the continuous adjustable amplitude. The research contents of this thesis were about the design of the inverter module which is a part of the AC current signal excitation source.The thesis expounded the overall design project about the AC current signal excitation source and the inverter module first, and put forward the SPWM control algorithm and the fuzzy PID algorithm which used to control the current wave shape, the current frequency and amplitude in the digital control mode. And then, it expounded the inverter module from two parts detailed, about the hardware circuit design and algorithm design.The hardware design can be divided into four parts:the minimum control system circuit module which used the DSP2812 chip; inverter bridge circuit module which included the inverter bridge, LC filter circuit, protection circuit and so on; inverter drive circuit module; the sampling circuit module about the current value which included the sampling circuit about the current instantaneous value and the sample current value handling, etc. The article designed them from the aspects of the circuit configuration, performance analysis, parameter setting and features implementation. And it gave the process to achieve the circuit and the parameters.The control strategy study included the power switching of the inverter control strategy and the sine wave amplitude feedback control strategy. The power switch of the inverter control strategy discussed the principle of the switch control algorithm, the way to design the digital controller about SPWM, the method to adjust the circuit frequency. The sine wave amplitude feedback control strategy discussed the method of the fuzzy PID controller.At last, we worked out the results to show that the control strategy achieved stable current amplitude which obtained better control effect.