The 4-leg Voltage Source Converter and its Application to Dynamic Voltage Restoration

A PWM scheme for the 4-leg voltage source converter (VSC) has been described. The technique is useful for generating unbalanced, 3-phase voltages, including a zero sequence component. It is simple and can be easily implemented in a digital signal processor (DSP). The proposed technique has been applied to the open-loop control of a laboratory-scale dynamic voltage restorer (DVR). Experimental and simulation results are presented to validate the proposed technique.