E-CVT control strategy of parallel-serial hybrid electric vehicles based on differential geometry method

PSHEV(parallel-serial hybrid electrical vehicle) has the advantages of serial and parallel HEV in that it includes the E-CVT(Electro-continuous variable transmission) structure. Whether E-CVT control strategy is good or not has a direct effect on the whole car´s fuel consumption and gas emission. Conventional PID algorithm is a kind of control method based on the error theory without consideration of research model specific characters leading to low precision of control and slow response of system. So a kind of control strategy based on DGM(differential geometry method) upon E-CVT of PSHEV has been proposed in this paper. Through the analysis of PSHEV transmission configuration, the control mathematic model of E-CVT in the PSHEV is built, then nonlinear controller based DGM is constructed. Finally, through the two kinds of algorithms simulation results comparison, it is concluded that DGM is better than PID on system dynamic response, stability aspects so that it can improve the whole car´s fuel consumption and power performance.