A new over modulation strategy for high-switching frequency space vector PWM voltage source inverters

In this paper a new space vector modulation (SVM) algorithm for voltage source inverters (VSI), employed in AC motor drives is presented. This algorithm calculates directly the switching pulse patterns for the inverter devices using an expression based on the definition of the duty cycle. By means of geometric considerations the over modulation range is detected without using trigonometric functions and avoiding to calculate the hexagon sector with the advantage of a lower calculation time and an increased switching frequency. Computer simulations have been carried out to verify the performance of the developed SVM strategy. Moreover the algorithm has been tested on an AC motor drive test bench, showing how, with respect to a conventional space vector modulation control algorithm, it allows one to increase the switching frequency up to the maximum switching frequency allowed by the inverter devices used in the test.