Equalizing the voltage of ANPC topology switches

Abstract:
ANPC topology is more and more popular in solar application. ANPC structure compared to NPC because of two additional switches and corresponding two neutral points commutation circuit, it can be more flexible and arbitrary configuration of the switches can make the loss is balanced. Solar inverter cooling system will be turned off when the power is low such as 100kW, which will lead to a decrease in heat dissipation capacity, when the temperature of different chips will be different, which will lead to uneven voltage distribution problems. This paper will explain how differences in chip temperature can lead to voltage imbalance, while consider the solutions to equalize the voltage.