Inverter Dead-Time and Non-Linearity Rejection Using a Wide Bandwidth Current Controller for PMSM Drives with a Speed Sensor

The dead-time and the other inverter nonlinearities known as the inverter non-idealities affect the output voltage and current distortions especially at low output voltages. The inverter non-idealities could be modeled as disturbances acting on the plant's (motor's) input. This paper discusses the effect of current controller design on the rejection of inverter non-idealities induced disturbances acting on the motor's terminals. Compensating for the inverter non-idealities through wide bandwidth current controller without the need of any additional compensation scheme is proposed, studied and verified experimentally at challenging operating conditions. The method is shown to be very suitable for permanent magnet synchronous motors (PMSM) drives with speed sensor as they do not rely on any estimation based on the reference voltage signal unlike sensorless vector induction motors (IM) and sensorless PMSM drives in general. Different design methods for PI current controllers are investigated along with a proposed current controller based on internal model control. The different current controller design techniques are then compared analytically and experimentally to highlight the most suitable one.