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

This study proposes a three-level dual-buck voltage balancer, which consists of two three-level buck circuits. It can split a DC input voltage source into two DC output voltage sources. The DC output voltage sources may have the same levels or different levels based on applications, while the sum of the two output voltages is always equal to the input voltage level. To achieve three-level states, a control strategy of introducing an extra freewheeling time is presented by adding a small extra DC bias voltage in the control loop. The operation principles are analysed in detail. In addition, the small-signal model is also given to design parameters. Finally, a prototype was built and tested based on a single output voltage loop in the lab. The experimental results had verified the balancer has a good ability for operating in three-level states and balancing output voltages.