Analytical Switching Model of a 1200V SiC MOSFET in a High-Frequency Series Resonant Pulsed Power Converter for Plasma Generation

Qunfang Wu,Guanliang Liu,Changqi You,Xiaoming Wang,Mengqi Wang,Weiyang Zhou

doi:10.1109/access.2019.2930535

Qunfang Wu, Guanliang Liu + Show 4 more

Open Access

https://doi.org/10.1109/access.2019.2930535

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Abstract

The circuit parasitic components have a significant effect on switching performance in the high-voltage and high-frequency pulsed power converter. The SiC MOSFET has better electrical characteristics than Si MOSFET and it is preferable in this application. In this paper, the characteristics of comparative study between Si and SiC MOSFET is provided first. Then, a converter-level analytical switching model for a 1200 V SiC MOSFET is proposed in a high-frequency series resonant pulsed power converter for the application of plasma generation. To increase the accuracy of predicting the behavior of the SiC MOSFET, the proposed analytical model involves all parasitic components in the converter, including the nonlinearity of the junction capacitances and transconductance, stray inductances from the package, printed circuit board (PCB) and transformer, parasitic capacitances from the transformer, and the capacitive load of plasma. The turn-on and turn-off transitions are analyzed in detail and the modeling mathematical equations are resolved by the MATLAB ode-45 command. The accuracy of this model is validated by comparing the analytical, LTspice simulated and experimental waveforms of a 400 VDC input, −8.2kV output prototype. The proposed model enables us to evaluate and optimize the switching solution of a SiC MOSFET for the pulsed power converter.

Highlights

Plasma generation has attracted a lot of attentions over the past few decades and has been widely used in different industrial fields such as ozone generation, material surface treatment, water processing, pollution treatment and biomedical applications [1], [2]
We find that so far, a great deal of effort has been done to model the single-discrete or power module SiC MOSFET that is the basic cell for power converters, but few efforts have focused on the analysis of the switching behavior from a converter-level perspective
During this interval, when iDs increases to 0 inversely, this stage ends and the drain-source voltage reaches its maximum value vds_peak . g) Sub-stage 7 [t7 ∼t8][See Figure 4(g)] In this substage, the SiC MOSFET is in the cut-off region and there is a resonance among the output capacitance Coss, resonant inductor Lr, and capacitors Cp and Cr

Summary

INTRODUCTION

Plasma generation has attracted a lot of attentions over the past few decades and has been widely used in different industrial fields such as ozone generation, material surface treatment, water processing, pollution treatment and biomedical applications [1], [2]. The rest of this paper is organized as follows: Section II presents the characteristics comparison of Si and SiC MOSFETs. Section III presents the proposed converter-level analytical model of a series resonant pulsed power converter and discusses the switch turn-on and turn-off transitions. The parasitic capacitances include junction capacitances Cgs, Cgd and Cds of the SiC MOSFET and parasitic capacitance Cd of the diode Dd. The parasitic inductances modeled are common source inductance Ls, drain inductance Ld , gate inductance Lg, and the resonant inductance Lr including the series inductance Lre and transformer leakage inductance Llk. In addition, the resistances considered are the gate resistance Rg including external resistance Rg(ext) and internal resistance Rg(int) and the equivalent series resistance of the power loop Rp. Due the transformer magnetizing inductance Lm, the core-loss resistance Rm and the load resistance Ro are relatively large, they are neglected during the high-speed switching process.

TURN-ON TRANSITION

TURN-OFF TRANSITION

CONCLUSION