Model free tuning of variable state of charge target of hybrid electric vehicles

Abstract This paper addresses a model free tuning method of the state of charge (SOC) target of a hybrid electric vehicle system. The methodology focuses on the variable SOC target which is governed by a linear equation of the actual vehicle speed. A simultaneous perturbation stochastic approximation (SPSA) based method is used to optimize the variable SOC target. The design method is applied to the JSAE-SICE benchmark problem which is developed using GT-SUITE of Gamma Technologies, Inc. and integrated with Simulink / MATLAB. Experimental results illustrate that the proposed controller can achieve almost 28 % improvements in fuel efficiency and keep 100 % driver's satisfaction.