Research On Vector Control System Of Induction Motor Based On DSP

With the development of power electronics and technology of motor control, AC speed regulation system has been applied everywhere in the industries. Vector control is one of the strategies of the AC motor drive with high performance. But vector control system performance depends on badly precision of motor parameters. The variation of rotor resistance will bring on variation of current and torque even the field orientation may be destroyed. There are two reasons which bring on inaccuracy of motor parameters. False initialization of induction motor parameters and variation of parameters in run of motor makeä»–that values which is used in system are unequal to actual parameter values. For accounting for the issues above, the research of motor parameter off-line identification and parameter on-line identification is done.Bad performance of induction motor vector control system is induced by false initialization of induction motor parameters. Traditional motor parameter identification scheme is plug experiment and no-load experiment. Traditional experiment is dangerous and identified parameters are not accurate. The induction motor parameters off-line identification scheme based on DSP is brought forward in the paper. Stator resistance, rotor resistance, mutual inductance and leaking inductance are identified by three experiments: DC experiment, single-phase AC experiment and no-load experiment. Pipeline voltage, switch delay and dead-time is taken into account. After analyzing the difference between the result identified and actual parameters, it's proved that the way is simple and reliable.Performance of system is badly influenced by the variation of motor parameters in run, especially rotor resistance. Rotor resistance on-line identification is researched unremitting, but ideal experiment results have not been brought forward. According to induction motor mathematical model, Rotor resistance on-line identification scheme based on MRAS is brought forward and adaptation scheme is designed. The result proves that this is effective.Finally, vector control system based on DSP is designed. The hardware structure and software design flow is given in detail. Motor parameters are identified accurately according to the method brought above and performance is excellent. The scheme has been applied in the inverter.