Reactive power and harmonic current compensation are considered as two important issues in the electrical power system since they have the strong impact on real power loss, voltage stability, resonance and operation cost. With recent development and deployment of distributed and renewable energy (power electronic converter interfaced) recourses the topic became more crucial. This paper presents a simple, yet effective cascade current controller which is analyzed and implemented on a single-phase grid-connected H-bridge and multilevel U-cell DC/AC converters (Inverters). The proposed controller is used for the single-phase STATCOM and shunt active power filter. The DC bus capacitor voltages in both converters are regulated with the proportional-integral (PI) controllers. The proposed controller tracks the AC reference current generated from the product of PI controller’s output with per unit value of the source voltage. The actual current input to the controller is measured from the grid side. The cascade operation of the PI and the proportional resonant (PR) controllers generates the control signal for the sinusoidal pulse width modulation (SPWM) module. The proposed controller is suitable for the grid-connected bidirectional AC/DC single-phase converters. The reactive power compensation and harmonic current elimination canbe carried out by using the fundamental component of the grid current in this controller. The performance of the controller is analyzed in Matlab/Simulink, and the results of simulation and experimental work are presented.
Keywords— Power Quality, Single-phase STATCOM, Shunt Active Power Filter, Current Controller.