Inverter Non-Idealities Override by Repetitive Control

High performance sensorless AC drives require the exact knowledge of the motor phase voltages in the whole speed range. The use of voltage sensors may be eschewed if the reference voltage signals, generated by the control algorithm, can be used instead. To this aim, an accurate compensation of most of inverter non-idealities is stringent. This paper presents a novel technique for the cancellation of inverter non-idealities, based on repetitive control. The main advantage is that the compensation automatically includes the IGBT parasitic effects during current zero-crossing, whose exact knowledge is one of the major problems in most of the standard dead-time cancellation techniques. Despite its elaborated theoretical background, the method requires few computational resources and it is easy to implement. Mathematical developments, design hints and an extensive batch of successful experimental tests are included in the paper.