面向光伏并网逆变器的混合PWM调制方法

发布时间：2018-07-11 12:32

本文选题：光伏并网逆变器 + 特定谐波消除　；参考：《浙江大学》2014年硕士论文

【摘要】：PWM调制方式是并网逆变器中的关键技术之一。相比于正弦波PWM调制(SPWM)和空间矢量调制(SVPWM)方法,特定谐波消除法(SHEPWM)具有等效开关频率低、输出电压质量好及损耗小等一系列优点。本文探讨了T型三电平光伏并网逆变器采用特定谐波消除法(SHEPWM)的适应性问题。首先介绍了特定消除法的原理及实现,比较了特定谐波消除法(SHEPWM)与空间矢量调制(SVPWM)两种PWM调制方式对逆变器电能质量、变换效率等影响。本文还分析了影响特定谐波消除法性能的几个因素,包括死区、母线电压纹波和电网谐波的影响。由于这些因素的存在,使得SHEPWM的输出电能质量下降,一定程度的降低了光伏并网逆变器的并网电能质量和整机效率。为克服这些因素,探讨了改进措施。针对SHEPWM动态性能差,不利于直接应用到低电压穿越等需要快速响应的场合的问题,本文提出了一种基于SHEPWM和SVPWM的混合调制方式,从而使得光伏并网逆变器具有很好的稳态和动态性能。此外,分析了影响两种调制方式的平滑快速切换的因素。在一台10kWT型三电平光伏并网逆变器实验平台上进行了相关的实验。
[Abstract]:PWM modulation is one of the key technologies in grid-connected inverter. Compared with sine wave PWM (SPWM) and space vector modulation (SVPWM), special harmonic elimination (SHEPWM) has a series of advantages, such as low equivalent switching frequency, good output voltage quality and low loss. In this paper, the adaptability of T type three-level photovoltaic grid-connected inverter using special harmonic elimination (ShePWM) is discussed. Firstly, the principle and implementation of the special elimination method are introduced, and the effects of special harmonic elimination (ShePWM) and space vector modulation (SVPWM) on the power quality and conversion efficiency of the inverter are compared. Several factors affecting the performance of specific harmonic elimination methods are also analyzed, including dead-time, bus voltage ripple and power grid harmonics. Because of these factors, the output power quality of SHEPWM is decreased, and the power quality and efficiency of PV grid-connected inverter are reduced to a certain extent. In order to overcome these factors, the improvement measures are discussed. Aiming at the problem that the dynamic performance of ShePWM is poor and it is unfavorable to be directly applied to low-voltage traversing and other situations requiring rapid response, a hybrid modulation method based on ShePWM and SVPWM is proposed in this paper. Therefore, the photovoltaic grid-connected inverter has good steady-state and dynamic performance. In addition, the factors that affect the smooth and fast switching of the two modulation modes are analyzed. Experiments were carried out on a 10 kWT three-level photovoltaic grid-connected inverter.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM464

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