Control strategy research of auxiliary power unit in range-extended electric bus

Auxiliary power unit (APU) is one major power source in extended-range electric vehicle. A new control strategy of auxiliary power unit applied in extended-range electric vehicle (EREV) is proposed in this paper. Considering the electric bus work requirements and road conditions, the bias-limited control strategy oversees the variable SOC and can be modified automatically, assuring its declining trend consistent with our design curve. The simulation model of APU system for 12m electric bus is constructed. Through the simulation, this new control strategy is verified to be feasible and reliable. Fuel economy is improved and a longer battery life can be expected.