Abstract

This study proposes a new strategy to decrease the switching frequency of the predictive torque control-discrete space vector modulation (PTC-DSVM) method, which is a combination of the PTC scheme and the DSVM. The principle of the PTC-DSVM method is based on selecting a sequence of voltage vectors, called virtual voltage vectors, instead of a single voltage vector and applying it to the power converter in prefixed time intervals. The proposed switching frequency reduction method operates based on appropriately arranging the voltage vectors forming the virtual voltage vector so that, on average, a maximum of one commutation per inverter switching state change is achieved. As a result of the suggested method, the average switching frequency is reduced in all operating conditions, while the performance of the proposed method remains as satisfactory as the conventional approach. The reduction of switching frequency also results in a decrease in the switching losses. The proposed method is an offline approach and selects the appropriate application order for the real voltage vectors based on the described rules, which do not impose any further computational load to the control algorithm. In order to validate the proposed method performance, the control algorithm has been implemented on a laboratory prototype.