Small Signal Modeling of Interleaved Voltage Balancer with Coupled-inductor

In bipolar DC microgrid, the interleaved type voltage balancer(VB) based on the coupled-inductor has an advantage of reducing inductance by coupling effect. However, the equivalent inductance of coupled-inductor has a inconstant value due to the switching state and mutual inductance. It can adversely affects to interleaved inductor current magnitude, phase differences, and even the worst case the operation of VB. Therefore, it requires a highly regulated controller. To design the controller, this paper proposes the small signal modeling to a precise plant model that considering the coupling effect and the load variation through the coupling coefficient k and regarding load as the current source. Base on propose small signal modeling, the controller satisfies the interleaving operation and fast load follow. According to the modeling results, simulation is implemented to confirm the feasibility and effectiveness.