Fast and Accurate Control Strategy for LCC Resonant Converters Based on Simplified State Trajectory and Two-Point Solution Method

Abstract

Fast and accurate optimization of the dynamic response is very important for an <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LCC</i> resonant converter. The trajectory control is an effective way to achieve these goals. However, the model of the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LCC</i> resonant converter is generally too complex to get the target steady-state operation frequency and trajectory online and in real time with the common controllers. In this article, a fast solution can be obtained by adopting the proposed two-point solution method. A simplified steady-state trajectory model is also established, which is the solution object of the two-point solution method. When the necessary parameters are acquired, the target state trajectory and operation parameters, e.g., frequency, can be obtained quickly and accurately. Furthermore, the fast and accurate control strategy based on the simplified state trajectory and the two-point solution method is proposed to realize control of the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LCC</i> converter. The experiments are performed to verify the proposed control strategy. During the load transient, compared with the conventional proportional–integral control, the voltage variation and the response time are improved by more than 80%, respectively, and the two-point solution method can be finished within 2.3 μs by the controller. The fast response with a very small voltage variation is realized by the proposed control strategy.