Multiloop interleaved control for three-level buck converter in solar charging applications

Abstract

In this paper, a nonisolated three-level (TL) buck converter is used for high voltage high power solar charging application. In order to search the maximum power point tracking (MPPT) point, keep the capacitor voltage balance and realize the function of constant current (CC) and constant voltage (CV) charging, a multiloop interleaved control (MIC) method is proposed. The proposed TL buck battery charger and the MIC method have the advantage of lower inductor current ripple, lower switch withstanding voltage and lower switching loss compared with the conventional buck charger. The proposed MIC method is digitally implemented by a digital-signal-processor (DSP)-based system. Simulation and experimental results based on a 4000 W prototype circuit are presented to demonstrate the effectiveness of the proposed control method.