The car is driven by an electric motor through a variable speed

The series power consists of three parts: engine, generator and electric motor. They are connected in series to form the SHEV power unit system. The engine drives the generator to generate electricity. The electric energy is transmitted to the battery or electric motor through the controller, and the electric motor passes through the transmission mechanism. Drive the car. When the load is light, the battery drives the electric motor to drive the wheels, and when the load is heavy, the engine drives the generator to generate electricity to drive the motor. When the vehicle is in starting, accelerating, and climbing conditions, the engine, generator set, and battery pack provide electrical energy to the motor; when the electric vehicle is in low speed, coasting, or idling conditions, the battery pack drives the motor. When there is power shortage, the battery pack is charged by the engine-generator set. The tandem structure is suitable for frequent starts and low-speed operating conditions in cities. The engine can be adjusted to run stably near the optimal operating point, and the vehicle speed can be adjusted by adjusting the output of the battery and electric motor. The engine avoids idling and low-speed operating conditions, thereby improving engine efficiency and reducing exhaust emissions. But its disadvantage is that the energy has been converted several times and the mechanical efficiency is low.