三相四线制逆变器软开关调制方法研究

发布时间：2018-02-13 00:38

本文关键词： 三相四线制逆变器零电压开关脉宽调制不平衡负载输出电容　出处：《浙江大学》2017年硕士论文　论文类型：学位论文

【摘要】：传统硬开关三相四线制逆变器使用正弦脉宽调制(SPWM)方法,其开关频率上限受到功率器件的动态损耗的限制,导致输出滤波元件体积大,给逆变器的小型化带来了困难,软开关技术是解决此类问题的有效方法。相比于其他软开关逆变器,零电压开关脉宽调制(ZVS-PWM)逆变器具有结构简单、开关器件电压应力小等特点。本文将ZVS-PWM引入三相四线制逆变器,该电路只需引入一个辅助开关和两个较小的无源元件,可以实现不平衡负载下电路中所有开关器件的零电压开通。本文介绍了三相四线制逆变器ZVS-PWM调制方法,在分析了电路工作过程的基础上,推导出了电路零电压开关的条件,根据条件计算了辅管关断占空比大小、谐振电感附加电流大小等理论值,给出了电路参数的设计方法。ZVS-PWM三相四线制逆变器中零电压开关的实现条件与谐振电容有关,谐振电容包含逆变桥中开关器件的输出电容。由于宽禁带器件SiCMOSFET的输出电容呈现非线性,会随着所承受的电压变化,在谐振过程中SiCMOSFET的端电压在零和最高值之间变化,导致谐振电容电容值也随着管压变化,会造成理论分析的变差。本文分析了开关器件输出电容对零电压开关实现的影响,探讨了开关器件等效输出电容的提取方法,以修正零电压开关条件的计算值。最后在10 kW SiC MOSFET的ZVS-PWM三相四线制逆变器样机上进行了实验验证。
[Abstract]:The traditional hard-switching three-phase four-wire inverter uses sinusoidal pulse width modulation (SPWM) method. The upper limit of switching frequency is limited by the dynamic loss of the power device, which leads to the large size of the output filter element and brings difficulties to the miniaturization of the inverter. Soft switching technology is an effective method to solve this problem. Compared with other soft-switching inverters, ZVS-PWM inverter has a simple structure. In this paper, ZVS-PWM is introduced into three-phase four-wire inverter, only one auxiliary switch and two smaller passive elements are introduced into the circuit. In this paper, the ZVS-PWM modulation method of three-phase four-wire inverter is introduced. Based on the analysis of the working process of the circuit, the conditions of the zero-voltage switch are derived. According to the conditions, the theoretical values such as the duty cycle of auxiliary tube turn-off and the additional current of resonant inductor are calculated. The design method of circuit parameters. ZVS-PWM three-phase four-wire inverter with zero voltage switch is related to the resonant capacitance. The resonant capacitor includes the output capacitance of the switching device in the inverter bridge. Because the output capacitance of the wide bandgap device SiCMOSFET is nonlinear, the terminal voltage of the SiCMOSFET varies between zero and the highest value during the resonant process, depending on the voltage it bears. In this paper, the effect of output capacitance on the realization of zero voltage switch is analyzed, and the method of extracting equivalent output capacitance of switch device is discussed. Finally, the experimental verification is carried out on the ZVS-PWM three-phase four-wire inverter prototype with 10kW SiC MOSFET.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM464

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