Adaptive SMC for the Second-Order Harmonic Ripple Mitigation: A Solution for the Micro-Inverter Applications

There have been several advanced topologies proposed by the community for micro-inverter applications. However, many such applications suffer from unwanted second-order harmonic current ripple at dc input. Moreover, in the absence of suitable passive filter or ripple compensator, the second-order harmonics ripple may propagate into the dc source. This results in several problems to the system, related to system efficiency, life, cost, size, reliability, and stability. This paper proposes an adaptive sliding-mode controller to shape the output impedance of the boost-circuit of quasi-switched boost inverter such that the propagation of the ripple from dc link to the dc-input source is resisted. The quasi-switched boost inverter is one of the advanced and suitable topologies for the micro-inverter applications. The adaptive nature of the proposed controller improves the transient performance of the system at the line-load transients unlike some existing solutions, which affects dynamics adversely to achieve ripple mitigation objective. The controller ensures voltage regulation within 5% at dc link. The proposed control technique is verified using a lab-prototype of 500 W quasi-switched boost inverter.