Design issues and performance analysis of CCM boost converters with RHP zero mitigation via inductor current sensing

The right-half plane (RHP) zero in the control to output voltage transfer function of a boost converter operating in the continuous conduction mode limits the loop bandwidth. By injecting a scaled version of the inductor current into the loop, it is possible to shift the zero from the right-half plane to the left-half plane, which leads to increased stability of the control loop. This solution generates a static voltage error at the output of the converter (tracking error), which may be unacceptable in practical applications. A few strategies to mitigate or correct this tracking error have been suggested. However, they have never been fully assessed. This paper thoroughly investigates the impact of the RHP zero mitigation technique on the dynamic performance of a boost converter, and identifies the complex trade-off between the system stability, transient response, and tracking error correction capability. Based on these findings, design guidelines are provided to help maximize system performance. A representative case study is considered to highlight the performance benefits and simulation results are presented to validate the analysis.