DSP Implementation of a Novel SPWM Algorithm Dedicated to the Delta Inverter

Abstract

The delta inverter is suggested to be the smallest three-phase dc/ac converter topology. It includes only three power switches compared to six in the conventional inverter. This reduced inverter topology is widely considered in many industrial applications, such as the electric traction and the large photovoltaic conversion systems. In this paper, a new sinusoidal pulse width modulation algorithm (SPWM) is developed for the reduced delta inverter. This algorithm is achieved by the development of irregular modulating functions waveforms of the sinusoidal modulation switching technique generated specially for the unconventional delta inverter's structure. Simulation results of the proposed SPWM algorithm carried out on a delta inverter feeding a three-phase RL load are acquired. Digital Signal Processor (DSP) implementation of the proposed SPWM method have been developed using an experimental board build around the laboratory prototype of the reduced delta inverter associated with an RL load as a first step and a squirrel cage induction machine as a second one. Experimental results have underlined its high performances considering the proposed SPWM algorithm.