Hybrid Voltage Balancing Approach for Series-Connected SiC MOSFETs for DC–AC Medium-Voltage Power Conversion Applications
Hybrid Voltage Balancing Approach for Series-Connected SiC MOSFETs for DC–AC Medium-Voltage Power Conversion Applications
复制标题
适用于 DC-AC 中压电源转换应用的串联 SiC MOSFET 的混合电压平衡方法
DOI：
10.1109/tpel.2022.3149146
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发表时间：
2022
影响因子：
6.7
通讯作者：
Dong, Dong
中科院分区：
文献类型：
--
作者：
Lin, Xiang;Ravi, Lakshmi;Burgos, Rolando;Dong, Dong
使用串联的sicmosfet来实现高速开关单元，以满足对高密度中压功率转换器日益增长的需求。由于硅基mosfet串联的开关速度快，其电压共享对周围寄生元件和门信号失配更为敏感，这给电压平衡控制带来了更多的挑战。本文首先以栅极关断延时时间控制为例，分析了现有有源电压平衡（AVB）控制方法的局限性：1)在交流电流条件下，AVB控制具有精确调节延时时间的局限性；2)本体二极管的电压不平衡无法通过AVB控制来解决。为了实现对交流电流的硅基mosfet的电压平衡控制，本文提出了一种新的混合控制方法：1)无源dv/dt补偿：用一个小的补偿电容来平衡被测寄生电容的不均匀分布；2)有源门信号关断时间调节：采用数字闭环延迟时间控制来补偿mosfet的门信号失配。为了验证所提出的平衡方法，进行了单相泵回测试，以显示双极效应管和体二极管的电压共享改善。
Using series-connected SiCmosfets to enable high-speed switching units is desired to meet the growing demand for high-density medium-voltage power converters. Due to its fast-switching speed, the voltage sharing of series-connected SiCmosfets is more sensitive to the surrounding parasitic components and gate-signal mismatch, which results in more challenges for the voltage balancing control. In this article, the gate turn-offdelay-time control is first used as an example to analyze the limitations of the existing active voltage balancing (AVB) control methods: 1) AVB control has a limitation of adjusting the delay time accurately under ac current conditions; and 2) the voltage imbalance of the body diodes cannot be solved by AVB control. To achieve voltage balancing control of series-connected SiCmosfets for ac current, this article proposes a new hybrid approach: 1) passivedv/dtcompensation: one small compensation capacitor is applied to balance the measured nonuniform distribution of parasitic capacitors;and 2) active gate signal turn-offtime adjustment: a digital closed-loop delay time control is applied to compensate the gate signal mismatch ofmosfets. To verify the proposed balancing approach, a single-phase pump-back test is conducted to show the improvement of voltage sharing of bothmosfets and body diodes.