Electric Vehicle Speed Controller Design

A comprehensive study of the AC speed-regulation controller for the exclusive use in Electric Vehicles (EV) is conducted in this dissertation.Firstly, the function design of the controller is proposed according to EV operating conditions. Consequently, the control circuit of the aforementioned controller using the TMS320F240 Digital Signal Processor (DSP) and the software architecture are designed.Secondly, the computer simulation platform for an AC speed-regulation system is built on a Matlab environment. Compared with other commonly used simulation models, the proposed one concentrates on the exploration of the mechanism of DSP controlled variable speed drives to yield more accurate simulation results. The simulation results reveal that (1) a control algorithm can be easily implemented, and (2) the function of a controller can be readily evaluated, in this platform.Also, two controllers, one is based on Vector Control theory and another on Direct Torque Control theory, are designed. Extensive numerical experiments are conducted to compare the performances of the proposed controllers with those of available general inverters. The numerical results as reported demonstrate not only the excellent speed-regulating performances of these controllers, especially the fast torque responding ability of the Direct Torque Control one, but also the technical feasibility of these two controllers.Based on the previous work, a Controller of Direct Torque Control and a general inverter are constructed. The experiments results show good agreement with the simulation ones, validating further the excellent performances of the Direct Torque Control algorithm.Finally, a novel switching technique is proposed to reduce the torque ripple of Direct Torque Controls. This technique uses a new torque adjustor and a new novel switching table. The experiment results validate the effectiveness and the feasibility of the proposed technique.