Stability and Small-Signal Analyses of the Dual Series-Resonant DC–DC Converter

The stability and small-signal analyses of the dual series-resonant dc-dc converter are investigated in this paper. The small-signal model of the converter is derived from the extended describing function analysis. Frequency-domain analysis is then employed to derive the small-signal transfer functions of the converter. This procedure establishes an insightful understanding about the effects of the converter parameters and operating conditions on the stability and transient behavior of the converter. The results are used to illustrate the development of the single-loop, voltage-feedback control scheme for the dual series-resonant dc-dc converter. It is demonstrated that the proposed control method enables the converter to regulate its output voltage in the case of abrupt changes in input voltage and output load, and it provides improvement in the transient response. An experimental prototype of the dual series-resonant dc-dc converter is built and the performance of the control scheme is experimentally evaluated by applying abrupt changes in the operating condition of the converter. Based on the experimental results, it is shown that the single-loop, voltage-feedback control scheme is effective in regulating the output voltage of the converter.