A new approach for DC bus voltage balancing in a solar electric vehicle charging station

Abstract

A voltage Balancing Control (BC) for the input voltage of a 3-level Neutral Point Clamped (3L-NPC) inverter is proposed. For renewable energy injection to AC grid, two independent sources are connected to the 3L-NPC via boost converters. The proposed BC allows independent MPPT for each source in a Distributed-MPPT (DMPPT). It is well known that the DMPPT offers 6.9-11.1% improvements in annual energy compared to a Centralized-MPPT (CMPPT). The stability of the proposed BC is analyzed and its effectiveness is validated by simulations and experimental results.