Inverter loss management for an electrical high-speed drive system

Constant velocity high-speed drives which are typically used in pumps, compressors or fans are supposed to be operated with high efficiency whereas dynamic behavior of the controlled drive system is of secondary priority. To ensure low-loss operation, the switching frequency has to be chosen as low as acceptable to guarantee stable operation without thermal overload of the PM-synchronous machine due to increased occurring voltage and current harmonics. That is why in this contribution pulse patterns of quarter-wave symmetry which are normally optimized offline with regard to certain objectives like the elimination of low-frequency harmonics are used in combination with an optimization algorithm that evaluates and manipulates various switching instants of the used pulse pattern in order to fulfill a given objective like the minimization of switching losses or total harmonic distortion for the current operating point best. Simulation results show that a reduction of switching losses of about 30% compared to the standard sine-triangular PWM can be achieved.