Abstract：DC micro-grid is a novel power system in dc distribution system, in which two-wire transmitting power mode is usually accepted. In order to balance input voltage of load sides’ power converters, a voltage balancer is introduced. In this paper, a three-level half bridge voltage balancer is presented to lower voltage stress of power devices. The operation principles of the circuit are explained in detail. The control strategy of lead turning on and lag turning off for power switches is proposed which helps power switches realize three-level operations. At last, the experimental results of a laboratory prototype verify that the three-level half bridge voltage balancer can achieve three-level characteristic and output balance voltage.
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2012, Vol. 27 
