Synchronous Frame Full-Order Observer Design for Three-Phase Buck-Type PWM Rectifier

This paper presents a synchronous reference frame full-order observer for a three-phase buck-type PWM rectifier that estimates both the currents of the input filter inductors and the voltages of the input filter capacitors. Either the currents or the voltages are needed in most cases to control the input grid power factor and the output dc voltage or current. For example, multiloop control strategies, which have been widely used for power rectifiers that are equipped with higher order LC or LCL input filters, require input filter currents or voltages. Using the proposed observer, the number of actual sensors needed for a buck-type rectifier control system can be reduced while maintaining fast dynamic performance and steady-state accuracy. The feasibility of the proposed technique is verified through MATLAB/PLECS simulations and experiments.