An Accurate, Universal, and Fast Time Domain Model for Different Types of Resonant Converters by Considering Parasitic Capacitors and Deadtime
Ziang Li, Shuo Zhang, Dachuan Chen, Peng Sun, Yanjie He, Quanming Luo, Jinjun Liu, Yuqi Wei
Abstract
The existing time domain models for <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">CLLLC</i> class resonant converters have at least one of the following drawbacks: 1) the model cannot be applied for different resonant tanks and circuit topologies; 2) the effect of parasitic capacitors and deadtime is ignored; 3) large computation time is required to obtain steady state waveforms. To address these issues, an advanced state-space based analysis (ASSA) model is proposed in this article. The operation stages by considering parasitic capacitors and deadtime are proposed and equivalent to a universal circuit, which largely increases the accuracy with low model complexity. Additionally, the ASSA model is universal for different inverter structures, rectifier structures, and different resonant tanks, including <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LC, LLC, CLL, CLLC, and CLLLC</i>. To improve the calculation speed, a hybrid operation mode analysis and ASSA model is proposed to obtain closer initial values and achieve steady state 2.15 times faster than traditional state-space based analysis methods. Finally, experimental results of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">CLLLC, CLLC</i>, and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> resonant converters working in multiple conditions are presented to validate the effectiveness and accuracy of the proposed ASSA model. Compared with the traditional time domain model, the relative error of resonant inductor current waveforms is reduced from 5.91%–43.54% to 2.83%–19.42%.