A Simplified Flying Capacitor Voltage Control Strategy for Hybrid Clamped Three-Level Boost Converter in Photovoltaic System

Abstract

This article proposed a simplified flying capacitor voltage (FCV) control strategy based on hybrid clamped three-level boost converter. Compared with the traditional control method, the proposed method does not need the sampling of the FCV and the extra FCV control loop. Hence, the software and hardware resources, like sampling circuits and control algorithm, can all be saved significantly especially in high voltage photovoltaic system with multiple dc inputs. In this article, the balancing mechanism and control parameter design of the proposed method are presented in detail. With the proposed strategy, the FCV can be controlled around half of the bus voltage with error less than 2%. Besides, a precharge strategy for flying capacitor is also provided in this article. The performance and analysis of the proposed strategy are verified by the experiments at last.