Reducing the Input Capacitance to Minimize the Right-Half-Plane Zero Effect for Buck Converters in Wireless Power Receiver Systems

Buck converters are widely used in wireless power receiver systems for voltage conversion, impedance matching, and power regulation. However, when the receiver's resonant network has a current-source nature, it introduces a right-half-plane zero in the control-to-output transfer function, which adversely affects the system's transient performance. This article presents a proposed solution by reducing the dc-link capacitance, which coincides with the input capacitance of the buck converter. The critical value of the input capacitance is examined through theoretical analysis and mathematical derivation. The experimental results demonstrate that reducing the input capacitance effectively mitigates output overshoot and reduces the adjustment time, thereby confirming the accuracy of the critical capacitance value.