Capability assessment of high-performance control schemes for PWM voltage-source rectifiers fed from weak power systems

It is a known fact that waning power systems worldwide are being supported using distributed power generation. This type of generation however adversely affects the end-users' power quality by increasing voltage and frequency disturbances. This paper presents a capability assessment of high-performance control schemes for PWM voltage source rectifiers operating under these conditions. The strategies considered are: a cascaded current/voltage scheme with PI controllers and a decoupling feedforward term, a cascaded nonlinear control scheme, and a paralleled current/voltage nonlinear control scheme. The analysis employs α-β stationary frame modeling and sequence decomposition theory. The strategies were implemented and experimentally tested using a TMS320C32 DSP based system. The evaluation considered industry standard disturbances, namely sags, swells, and frequency fluctuations. Results obtained showed that the paralleled nonlinear scheme presents the best performance.