Harmonic Analysis And Suppression Of High Frequency Inverter System In FCEV

With the emergence of energy crisis and enviromental pollution, the vehicle with internal-combustion engine is faced with a rigorous challenge. The fuel cell electric vehicle(FCEV) as a new electric vehicle is being taken into consideration. For the actual operating condition of the vehicle changes in a tochastic variable, the stability of the fuel cell system is seriously effected by harmonic current caused by the variable conditions. Therefore the harmonic suppression has been one of the key links in the study of FCEV.The thesis is proposed with consideration of the harmonic current. To realize the real-time compensation of the harmonic, a time-changed active power filter(APF) is set in the output side of the inverter. Theoretical analysis and simulation results show the good performance of harmonic compensation by the time-changed method, which able to meet requirements of the system.This thesis analyzed the harmonic characteristics of pulse width modulation (PWM) and pulse amplitude modulation (PAM) based on the specificity of the fuel cell system firstly, the simulation results show that PAM-controlled inverter has a better output harmonic performance. Secondly, the time-changed APF is proposed based on the dynamic performance requirements. The time can be changed by the variation of harmonic current detected. The theoretical analysis and simulation results show that the tracking error is decreased in the time-changed method compared with traditional time-control hysteresis current method. Besides, the time-changed controlled method maintain the switching frequency stability in a certain sampling period. Finally, the simulation results show the inverter system, which is combined the PAM-controlled inverter with the time-changed hysteresis current controller, eliminates the harmonic components of the inverter system effectively, and improves the stability of the system.