A novel low cost PV micro-inverters based on analog control and interleaving method

Abstract

This paper proposes a novel simplified low cost analog implementation of a master/slave methodology resulting in an efficient soft-switched interleaved variable frequency flybacks operating in the boundary conduction mode (BCM). The scheme is suitable for PV micro-inverters and other applications such as battery chargers. The circuit allows for master/slave synchronization while copying the ON time of the master flyback to the slave one, which result in component count and cost reduction. The proposed discrete analog implementation utilizes a drive winding embedded in the master flyback transformer, which also controls the start of the ON time of the slave flyback. Hence, a voltage control oscillator (VCO) method is adopted. Such technique helps simplify the control and reduce the losses of the drive circuits while eliminating the need for an auxiliary startup supply. Operation procedure, design considerations, and experimental results are presented in this paper. The implementation simplicity of the scheme at low cost is demonstrated while reaching impressive performance. Keywords-PV micro-inverters; interleaved BCM variable frequency flybacks; master/slave synchronization; voltage control oscillator; low cost; analog implementation I.978-1-4799-6735-3/15/$31.00 ©2015 IEEE