Solutions for Reducing and Controlling Voltage Unbalance in HERIC Inverters

Inhalt:
This paper analyzes the voltage unbalance that occurs when turn-off transitions between MOSFETs are not synchronized in HERIC inverters and the key role played by the MOSFETs on the active leg. Due to the topology of these converters, with the two middle points connected by two active switches and two diodes, the switching transitions need to be handled carefully to avoid any voltage unbalance between MOSFET terminals. The voltage unbalance is influenced by PCB layout, routings, and intrinsic MOSFET capacitances. In this paper, several applicative solutions are presented for mitigating this effect.