Charge Equalization Based-on Three-Level NPC Converter for Series Connected Battery Strings

摘要

The main purpose of this paper is to design a charge equalization circuit for series connected lead-acid batteries. The charger utilizes a three-level neutral point clamped (NPC) AC/DC converter with voltage balance control to charge the series connected rechargeable battery strings. This paper details the operation principles of the charge equalization circuit under different operation modes and derives the governed equations. The proposed charge equalization circuit can not only regulate the power factor of AC source side, but also can balance the charge voltage for series connected rechargeable batteries. Finally, some simulation results are made to demonstrate the effectiveness of the charge equalization circuit scheme presented in this paper.