Modeling And Control Strategy Of Fuel Cell DC/DC Converter Based On PW

With the consumption of fossil fuels and the pollution of environment,fuel cell vehicles have gradually entered people’s vision.Due to the slow response speed and wide range of output voltage variation,fuel cells can not directly meet the voltage level requirements of automotive busbar and require DC/DC converters for regulation.In this paper,a composite Sliding mode control strategy is proposed to improve the anti-interference and dynamic characteristics of three-phase interleaved boost converter with pulse width modulation(PWM).(1)A DC/DC converter topology is designed.Based on the output characteristics of fuel cells,the design indicators of DC/DC converters are determined,and a three-phase interleaved parallel boost converter topology is established.Analyze the working mode,working state,and ripple suppression coefficient,and calculate the parameters of the components.(2)A mathematical model of DC/DC converter is established.The average state space equation,time domain small-signal modeling and frequency domain small-signal modeling are obtained by averaging,linearizing and frequency domain transformation of the state equation of three-phase interleaved boost converter,and the open-loop transfer function from the control quantity to the output voltage is derived,and its stability is analyzed through the Bode diagram.(3)The compound Sliding mode control strategy of DC/DC converter is designed.Based on the Sliding mode control principle of PWM DC/DC converter,a nonsingular terminal sliding mode controller(NTSMC)is established.The extended state observer(ESO)and generalized proportional integral observer(GPIO)are designed.A nonsingular fast terminal Sliding mode control(GPIO+NFTSMC)based on generalized proportional integral observer is proposed.The simulation results show that GPIO+NFTSMC has better antiinterference and dynamic characteristics compared to the other two control strategies.(4)The efficiency and operating mode of the DC/DC converter is analyzed.For the hybrid power system of fuel cell vehicles,the working efficiency of DC/DC converters under different input voltages,as well as the changes in bus voltage and current under the switching of four working modes,are analyzed to verify the effectiveness of the designed converter.By analyzing and designing the topology and control strategy of a PWM based fuel cell DC/DC converter,it meets the requirements of anti-interference,dynamic characteristics,and work efficiency.