Symmetrical PWM with a split-capacitor single-phase to three-phase converter for rural electrification

In this paper, a six-switch split capacitor topology for low cost single phase to three-phase conversion is introduced and evaluated against other topologies (Van Dyk, Enjety). The new topology has a reduced number of power electronic devices, which reduces the overall cost and size of the system. The currents drawn from the line are sinusoidal and this is achieved by an active input current shaping feature. The converter also provides a bi-directional flow of power from the line to the load it provides regulation against fluctuations in the source voltage, does not have the disadvantages of asymmetrical PWM, and enables space vector voltage switching scheme. A method used to control the converter is discussed. A simulation of various aspects of the proposed topology is investigated. A conversion to variable speed drive is also investigated. Experimental results are given and recommendations for applications are discussed