Hybrid Switched Reluctance Motor and Drives Applied on a Hybrid Electric Car

Abstract

Electric machine is one of key parts in hybrid electric vehicles which affect dynamical and fuel consumption features and is the kernel to realize all kinds of strategy. Induction motor, PM synchronous motor, brushless DC motor, and switched reluctance motor are all applied in HEV. Traction motors for HEV are different from motors applied in industry. Load changes frequently and widely. Characteristics such as high maximum torque and maximum speed, high ratio of maximum speed to base speed usually larger than 4, high efficiency over whole work area, smaller volume and lighter weight with high power are demanded. Moreover, electric machine is usually installed on the chassis on which the environment is vibrative, dusty and moist. So characteristics of traction motors for HEV should be as follows, high power and torque density, extended speed range, high efficiency over whole working area, shockproof, waterproof, and dustproof.[1] A novel hybrid switched reluctance motor drives are developed. With simple flux adjusting, large torque and high speed are achieved. With a coil stationary in the motor, rotor position is detected and speed is calculated. The torque-speed characteristic curve and system efficiency map of the electric machinery applied on HEV are important items in power assembly test. The electric machinery will help to start the engine or the vehicle, assist to drive the vehicle, charge the battery and absorb the braking power or sometimes reverse the vehicle. So the electric machines often work in both motor and generator mode, and sometimes run both forward and reversal. It is to say that the working torque-speed area is distributed in 2 or 4 quadrants. The magnetic particle brake and electric eddy current load as in normal electric machinery test bed cannot work because they cannot drag the tested electric machinery. Some electrical dynamometer can do that kind of test. But with the unit of generating to the grid, the system is expensive. A bench is developed to test the motor drives. It is energy saving and no power flows to the grid.