Magnetics design for active transient voltage compensator

This paper is mainly focused on how to design the transformer to meet the requirements of active transient voltage compensator (ATVC) circuit. The FEM transformer design method is discussed in detail. ATVC is a solution to the challenging transient requirement of VRM under high slew rate load current. It only works in transient periods and the main VR operates in low frequency which results in high efficiency. In the steady state, the transformer is just a paralleled large filter inductor. In transient periods, ATVC acts as a transformer, injecting or absorbing high slew rate current that is determined by the transformer leakage inductance. The numerical FEM method is used to design the transformer according to the transformer's actual working conditions. The accurate and frequency dependable transformer magnetizing inductance value and the leakage inductance value of each winding can be decided from the FEM results directly. The simulation and experiment results verify this transformer design. The circuit slew rate can reach the 0.11 A/us.