Three‐level dual‐buck voltage balancer with active output voltagesbalancing

Abstract

This study proposes a three‐level dual‐buck voltage balancer, which consists oftwo three‐level buck circuits. It can split a DC input voltage source into twoDC output voltage sources. The DC output voltage sources may have the samelevels or different levels based on applications, while the sum of the twooutput voltages is always equal to the input voltage level. To achievethree‐level states, a control strategy of introducing an extra freewheeling timeis presented by adding a small extra DC bias voltage in the control loop. Theoperation principles are analysed in detail. In addition, the small‐signal modelis also given to design parameters. Finally, a prototype was built and testedbased on a single output voltage loop in the lab. The experimental results hadverified the balancer has a good ability for operating in three‐level states andbalancing output voltages.