Research On Electrical Vehicles Drive System Based On Switching Reluctance Motor

Automobile is an important transportation tool in human’s daily life, however, the development of which has caused all kinds of environmental concerns. Therefore, the research of green energy electrical vehicles becomes the mainstream of automobile industry. At present, there exist various kinds of motors applied in electrical cars, among which the switching reluctance motor obtains much more attention from researchers due to its high reliability, simple structure, flexible control, large starting torque, small starting current and other significant advantages. The thesis takes the3-phase12/8polar switching reluctance motor as an example, makes explicit analysis on the drive system of electrical vehicles based on the switching reluctance motor and designs an applicable drive system of the switching reluctance motor for electrical vehicles.Firstly, structure and runnability of the electrical vehicles are analyzed. And then a feasible control strategy is devised according to its mathematical models and speed regulation characteristic:dividing the speed range within0-3000r/min into four intervals, in accordance to the specific speed controlling it with starting chopping, commuting naturally, changing angle chopping, single pulse control respectively; using the acceleration start mode to shorten the starting time; changing the chopper upper limit to produce enough torque when climbing; applying the electric braking to the braking and speed mutation prevention conditions to achieve the energy efficient and security effects.Secondly, on the basis of definite control direction and strategy of the switching reluctance motor, the specific hardware circuits which selected dsPIC33FJ128MC706as the main control chip, consisting of power converter, switching power supply, drive circuit, detection circuit and minimum system circuit, are designed according to the principle of safety, reliability and cost reduction. Meanwhile, the function models in the software are analyzed in details. Main routine, initializer, acceleration start, climbing, speed mutation, PI adjustment, interrupt, protection and so on are involved in the main function module.In the end, the software and hardware of the entire drive system are debugged. Also, truck loading tests are conducted. The test results show the breakaway starting current is only90A, which is much lower than the original driving system. And the one charge operating range increase by11%, too. The experimental results show that the system designed in this paper can satisfy the driving requirement of electric vehicle.