Delay-Dependent MIMO Robust Control for Power Following System of Auxiliary Power Unit in Series Hybrid Electric Vehicles
Feng Han, Jie Ye, Wenyu Xiong, Qichangyi Gong, Jinbang Xu
Abstract
In order to improve the transient and static performances of power following system in series hybrid electric vehicle (SHEV), this paper presents a delay-dependent MIMO robust control strategy. The control scheme coordinates the engine and the generator in the auxiliary power unit (APU) to reach the optimal speed and torque synchronously to output the required power. By the way of Pade approximation and multiple linear regression analysis, the delay time uncertainty in engine torque response is emphatically analyzed, which improves the accuracy of the engine torque model. The stability of the system is ensured theoretically by the Lyapunov Stability Theory and a sufficiently robust stability condition is established in terms of the linear matrix inequality (LMI). To avoid the problem of power reverse undershoot, a method of directly limiting the generator torque command is adopted, which is analyzed to not affect the stability of the system. The effectiveness and practicability of the proposed control strategy are demonstrated through numerical simulations and experiments.