Pulse by pulse current limiting technique for SPWM inverters

Abstract

Impactive current overshoot is usually observed in SPWM inverter when impulsive loads are loaded. So far, several methods have been proposed to solve this problem, such as mean current feedback control or temporarily pulling down the voltage reference. Nevertheless, they both have shortcomings. This paper introduces a pulse by pulse current limiting (i.e. instantaneous drive pulse locking) technique which can substantially lessen the impact on SPWM inverter during all kinds of impulsive loading (even the short-circuit of the load). This technique has been used successfully in a 3.5 kW, 400 Hz single-phase full-bridge SPWM inverter. By the pulse by pulse current limiting technique, the successful loading of impulsive loads is ensured, and the loading process has little influence on the normal supply to other important loads which are powered by the inverter at the same time.