The Research On Control Strategy For AC Motor Running As Single Phase Based On DSP

This thesis is chiefly contributed to the deep study of the transient unbalanced short circuit of induction machine, simulation model and space vector pulse width modulation for single-phase AC driver system based on the high performance digital signal processor about control system structure, hardware and software design etc, which the induction motor is taken as control plant, the digital signal processor TMS320LF2407A as control core, interactive MATLAB/SIMULINK as simulation tools. This thesis impressed on control strategy by which three-phase induction machine operates as single-phase AC under unbalanced faults. On the basis of the superposition principle and Laplace transformation, the process of the transient state under different short circuit states of induction machine is analyzed. The analytical method of transient state to induction machine using the principle of harmonic balance is recommended at the same time. The induction machine simulation model is introduced for asymmetric connection. The limit conditions for the end voltage of the induction machine are derived, according to the asymmetric condition of the machine stator winding. The simulation platform based on MATLAB/SIMULINK is built. The detailed simulation result is provided, and the result is analyzed from the theoretical foundation. Concerned about faults operating process of three-phase induction motor with stator one phase short circuit and stator two phase short circuit, space vector PWM techniques for two-phase inverter-fed and for three-leg voltage source inverter are introduced, by which three phase induction motor with stator one phase short circuit or stator two phase short circuit operate as single phase state. The hardware and software's design scheme of all digital AC drive system is proposed based on high performance digital signal processor TMS320LF2407A and Intelligent Power Module (IPM). The function blocks of control system are particularly described and the circuit configurations are given. This scheme makes the system design more simple, the structure more compact, the performance more optimized, the reliability more high. On the basis of Space vector PWM techniques for three-leg voltage source inverter, the detailed descriptions about DSP assembler language program design characteristic and methods are introduced. The control algorithm is realized using DSP assembler language, by which three phase induction motor with stator one phase short circuit or stator two-phase short circuit operate as single-phase state.