An Improved Power-Decoupling Scheme with Grid Inductor Phase-Shift Modification for Single-Phase Converter

Active power decoupling (APD) techniques are widely used in single-phase PWM rectifiers under 10 kilowatts, which prove to be efficient in cutting passive component size (usually against bulky electrolytic capacitors at dc side). However, it is found that the reactive power caused by boost inductor cannot be ignored especially in low input voltage, high power situation with large input inductance. Such reactive power could bring an obvious phase-shifted angle ϕ to dc side current, which contributes to the steady state error in decoupling reference for APD circuit. This paper presents a strategy by modifying ϕ to achieve the ac-side inductor reactive power compensation (IRPC) without adding any hardware, which could further reduce dc-link capacitance. Compared with the traditional control method that usually neglects reactive power stored by inductor, a more effective power-decoupling IRPC scheme is validated experimentally with a 1kW prototype.