Improved optimal sliding mode control and operating strategy for turbine-based air compressor in automotive fuel cells with driving cycles analysis

Fuel cells are developing towards high power output. As a key auxiliary component of fuel cell systems, adopting a turbine-based air compressor combined with energy recovery technology can effectively reduce parasitic power consumption. However, the ultra-high speed and expansion torque interference of compressors pose challenges for control and management. To improve the output stability of the air compressor and enhance the system efficiency, a coupling model (mean-relative error of 6.313 %) including the compressor static characteristics and motor dynamics is established, and an optimal sliding mode surface containing all system state matrix and weighted matrix information is designed to achieve compressor superior dynamic and steady-state performance, and an operating strategy of the compressor by regulating oxygen excess ratio is developed to avoid the expansion end working inefficiently. Numerical simulations were conducted under the China heavy-duty commercial vehicle test cycle (CHTC). Compared to traditional methods, the speed control root-mean-square error was reduced by 2.67 %, and the power consumption of the compressor was also lowered. Furthermore, the hardware-in-the-loop test results were in high agreement with the simulations, confirming the feasibility of the proposed controller. The proposed control strategy could significantly improve the performance of the turbine-based air compressor and indicates the practical feasibility.