In this article, a quasi-resonant (QR) flyback converter has been proposed for capacitor charging in a pulsed plasma thruster (PPT) of a nano-satellite. The energy in the transformer leakage inductance can be recycled to the resonant capacitor, suppressing the switch-off voltage spikes on the semiconductor power switch. The power switch is turned on with a hybrid switching mode. In this mode, valley-voltage-switching (VVS) is applied until the zero-voltage stress on the power switch is obtained, and zero-voltage-switching (ZVS) is used in the remaining charging process. Consequently, the switching-on loss is reduced, and charging efficiency is improved. When a capacitor bank of $2\mu \text{F}$ is charged to 1.5 kV (i.e., 2.25 J), the switching loss contribution of QR flyback converter using hybrid switching approach is reduced significantly to 0.61% while a flyback converter using hard-switching technique has a switching loss contribution of 15.24%. As a result, the proposed QR flyback converter improves the charging efficiency by 2.43%, from 72.69% to 75.12%. Moreover, the diode in the secondary side can be turned-on with zero-voltage and off with zero-current. Hence, the turn-on overshoot voltage and recovery loss are reduced.

中文翻译：

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纳米卫星脉冲等离子体推进器准谐振方法电容器充电

在本文中，提出了一种准谐振 (QR) 反激式转换器，用于纳米卫星脉冲等离子体推进器 (PPT) 中的电容器充电。变压器漏感中的能量可以循环到谐振电容器，抑制半导体功率开关上的关断电压尖峰。电源开关以混合开关模式打开。在这种模式下，应用谷电压开关 (VVS) 直到获得电源开关上的零电压应力，并在剩余的充电过程中使用零电压开关 (ZVS)。因此，降低了导通损耗，提高了充电效率。当 $2\mu\text{F}$ 的电容器组充电至 1.5 kV（即 2.25 J）时，使用混合开关方法的 QR 反激式转换器的开关损耗贡献显着降低至 0。61% 而使用硬开关技术的反激式转换器的开关损耗贡献为 15.24%。因此，所提出的 QR 反激式转换器将充电效率提高了 2.43%，从 72.69% 提高到 75.12%。此外，次级侧的二极管可以零电压开启，零电流关闭。因此，导通过冲电压和恢复损耗降低。