Single-Phase STATCOM with Multilevel U-Cell Converter

This paper presents a control algorithm and its implementation on a grid connected single phase multilevel U-cell converter for reactive power control. The sinusoidal pulse width modulation is used for the control of five-level voltage source converter. The phase angle of grid voltage is obtained by using a single-phase phase-locked loop and two modulation signals are compared with a single carrier wave in order to control the IGBTs. The orthogonal voltage waveform which has 90 degrees phase shift with respect to source voltage is generated by using a second order generalized integrator. The implementation of the proposed controller has been carried out in the laboratory by using TMS320F28335 floating point digital signal processor.