Fixed time power regulation control strategy for power system in fuel cell hybrid electric vehicles

The energy management strategy plays a pivotal role in achieving energy efficiency in fuel cell hybrid electric vehicles. However, the insufficient dynamic performance of the DC/DC converter used in the distribution strategy can affect power distribution. To address this issue, a fixed time power control strategy for hybrid power system in fuel cell hybrid electric vehicle is proposed. The fuel cell acts as the primary power source, utilizing a Boost converter to provide average power. Simultaneously, the ultracapacitor functions as an auxiliary power source, utilizing a Buck-Boost converter to deliver instantaneous power and compensate for power fluctuations in the primary source. To achieve simultaneous fast tracking control of both converters, a comprehensive model of the hybrid energy system is established based on the Boost and Buck-Boost model. Subsequently, a f ixed time hybrid power controller is designed using fixed time control theory to stabilize the bus voltage and accurately and rapidly track the reference current of the ultracapacitor. This strategy overcomes the reliance on the initial state of the hybrid power system inherent in traditional control strategies, thereby enhancing dynamic performance and enabling optimal energy distribution. Finally, the proposed controller and PID controller are compared under WLTC (World Light Vehicle Test Cycle), and comparative experiments are conducted on a real laboratory vehicle test platform. The simulation and experimental results show that the proposed strategy can achieve bus voltage fluctuations of less than 2% and maximum tracking error rate of less than 3%.