摘要:本文主要研究了单相电压型逆变电路的谐波特性，并运用MATLAB对其进行了仿真分析。在研究它的谐波特性之前，首先分析了单相电压型逆变电路的工作原理和移相调压方式，然后利用Simulink进行建模仿真，用仿真结果验证了单相电压型逆变电路的工作原理，并且得到了其谐波分布规律。同时本文在研究了单相电压型逆变电路的几种PWM调制方法的基础上，对正弦脉宽调制（SPWM）的单相电压型逆变电路的输出电压进行了研究。首先通过理论分析出SPWM型逆变电路的谐波规律与载波比、调制度以及负载之间的关系。然后利用MATLAB进行仿真，通过改变参数从不同的仿真结果中得出了输出电压谐波的分布规律，同时也发现了采用SPWM调制的逆变电路，它的总谐波畸变率的变化规律是和载波比以及调制度紧密关联在一起的。在保持载波比大小不变的情况下，调整调制度的数值，调制度越大，总谐波畸变率则越小；保持调制深度不变同时又使载波比数值较大时，调整载波比的数值，对输出电压的总谐波畸变率基本不会造成影响。而负载也对谐波特性有一定的影响，增加电感的数值也可以提升输出电流的波形质量验证了前面的理论分析。因此在实际应用时，为了在输出测得到较好的正弦波，应该充分考虑调制度与载波比对谐波的影响，既要增加载波比又要增加调制度。最后，本文研究了相应的滤波器的发展趋势，并从载波频率与无功功率的角度针对单相PWM逆变电路提供了一种滤波思路。

关键词：正弦脉宽调制；谐波；调制深度；载波比

Abstract:In this paper, the harmonic characteristics of single-phase voltage-type inverter circuit are studied, and the simulation is carried out by MATLAB. Before studying its harmonic characteristics, the working principle and phase shift voltage regulation mode of single-phase voltage inverter are analyzed. Simulink is used to simulate and simulate. The simulation results verify that the single-phase voltage inverter circuit Working principle, and got its harmonic distribution law. At the same time, based on the research of several PWM modulation methods of single-phase voltage inverter, the output voltage of single-phase voltage inverter circuit with sinusoidal pulse width modulation (SPWM) is studied. Firstly, the relationship between the harmonic law, carrier ratio, modulation degree and load of SPWM inverter circuit is analyzed theoretically. And then the simulation of the output voltage harmonics is obtained by changing the parameters from different simulation results. The inverter circuit with SPWM modulation is found. The variation law of the total harmonic distortion rate is Carrier ratio and modulation degree are closely related. In the case of keeping the carrier ratio unchanged, adjust the modulation value, the greater the modulation degree, the smaller the total harmonic distortion rate; keep the modulation depth unchanged while the carrier ratio value is larger, adjust the carrier ratio  Value,  the total harmonic distortion rate of the output voltage is not substantially affected. And the load also has a certain impact on the harmonic characteristics, increase the value of the inductor can also improve the output current waveform quality to verify the previous theoretical analysis. Therefore, in practical application, in order to produce a better sine wave in the output, we should fully consider the impact of modulation and carrier ratio on the harmonic, it is necessary to increase the carrier ratio and increase the modulation degree. Finally, this paper studies the development trend of the corresponding filter, and provides a filtering idea for the single-phase PWM inverter circuit from the angle of carrier frequency and reactive power

Keywords: SPWM; harmonics; modulation depth; carrier ratio

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