Control and Modelling of a New Space-Vector PWM Strategy for Improved Induction Motor Drive Reliability

J. Kliíma and L. Schreier (Czech Republic)


Modelling, induction motor, reliability, inverter


Three-phase voltage source (VSI) induction motor drives are prone to different inverter faults that cause the drive system to shut down. This paper investigate by the analytical model the utilization of a simplified topology that permits the fault tolerance operation of a three-phase induction machine fed from the voltage source inverter when one of the inverter leg is lost. In that case, the machine phase with a lost inverter leg is connected to a zero DC voltage point to maintain balanced operation. The space-vector modulation strategy which is proposed has the same symmetry as for the B6 inverter and is simple without significant increase in switching frequency. It is also shown that derived time portions allocated to the proposed modulation strategy in the B4 connection are similar to that time portions derived for the classical B6 inverter. From the mathematical model we can derive both the steady-state and transient characteristics of the motor. Finally, analytical model is verified experimentally and close agreement between analytical and measured waveforms is found

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