HEV system based on electric variable transmission

A HEV system is developed. The system introduces an electric variable transmission (EVT) motor system as the energy coupler and converter which replaces the generator and motor in a typical series HEV, resulting in higher flexibility, efficiency and a compact size. The system configuration and control strategies for motor, ICE and battery are explained in detail. Simulation validates the feasibility of the configuration and shows the improvement in fuel economy compared with the base model. A test bench is built to carry out lab test. Control parameters in transient conditions, such as the engine starting and stopping, engine power tracking the road load demand, are carefully fine tuned in the test, to reduce impact due to inconsistence, resulting in a smooth drive and high efficiency.