The key to control the range extender generation system is to improve efficiency and reduce the emission of the electric vehicle.In this paper

based on the purpose of efficiency optimization

both engine and generator are matched to get a public high-efficiency region

and a multi-point speed switching power following control strategy is presented.Engine speed is operated on the defined points according to required driving power and minimum fuel consumption curve.The engine speed is constant

and then generator torque is regulated on each constant speed points.Engine speed and generator torque are decoupled.To ensure the response characteristics of control system and improve the robustness

a multi-frequency proportional resonant controller（MFPR） is adopted to eliminate static error of generator output current.The impacts of MFPR controller parameters on system’s characteristics and stability are analyzed.A general method for control system parameters design and stability design is proposed by using the control theory criterion.The phase margin of the designed control system is 30o<γ<60o

the amplitude margin is h>6 d B which meet the stability requirements.The simulation and experiment verify that the designed power following control strategy has good dynamic response and stability.