An Analysis on Switching Loss Optimized PWM Strategies for Three Phase PWM Voltage Source Converters

The pulse width modulation of power converters is an operation parameter that exhibits a great influence on occurring semiconductor losses. Especially the switching losses can be reduced significantly by applying the appropriate PWM method maintaining the value of pulse frequency. To achieve such effect usually a so called discontinuous PWM is applied. But there is still a certain degree of freedom in using such PWM strategy. Thus the question for the optimal adjustment to the corresponding operation point arises. This work derives the basic rules for adjusting the discontinuous PWM appropriately with special focus on the semiconductor switching losses. The theoretical results are validated by experimental evidence that was gained at a calorimetric test set up.