An Accurate and Universal Time Domain Model for Different Resonant Converters by Considering Non-ideal Effects

The CLLLC class resonant converters are widely applied in different industry applications as a promising topology for isolated bidirectional power conversion. During the traditional design stage, the fundamental harmonic approximation (FHA) modeling method is commonly used. However, resonant converters are oftenly applied in wide gain range applications, which makes FHA not accurate and leads to conversative design of the system and degraded performance. Therefore, time domain model is proposed to improve the accuracy and achieve optimal design of the resonant converters. However, the existing time domain models have at least one of the following issues: 1) the effect of parasitic capacitors is neglected; 2) the effect of deadtime is neglected; 3) the model cannot be easily applied for different resonant tanks. To address these issues, an accurate and universal time domain model for resonant converter is proposed in this paper. By deriving the time domain model for the most complicated CLLLC resonant converter with asymmetric resonant tank parameters, a universal model can be obtained for different resonant tanks, including LC, LLC, CLL, CLLC, CLLLC with symmetric and asymmetric parameters. By simply modifying the working stages, the effects of parasitic capacitors and deadtime are precisely considered in the proposed model. Compared with the traditional time domain model, the experimental results show that the maximum error reduction is from 52.53% to 5.81%.