Order Reduction for High-Order WPT Modeling: A Balanced Residual Method to Small-Signal Modeling

This paper proposes a simplified modeling approach based on the balanced residual method for the order reduction of high-order small-signal models of LCC-S compensated wireless power transfer (WPT) systems. First, the order reduction performance and matching degrees to the original model of the balanced truncation method and the balanced residual method are compared in both the time domain and frequency domain perspectives. Based on these comparisons, the balanced residual method is selected for the order reduction modeling of the high-order WPT system, and controller parameter design criteria are provided following the model reduction. Then, the actual battery charging state was simulated using a programmable resistor, achieving the constant current (CC) and constant voltage (CV) charging modes. By reducing the order of high-order model, the design of the control scheme is indirectly simplified and the closed-loop design process is accelerated. Finally, a real LCC-S WPT system designed based on the simplified modeling approach is built and tested. The final achieved control effect has good robustness and is easy to implement, which proves the feasibility and effectiveness of the control after order reduction.