| 摘要: |
| 逆变器的并联由于具有容量大、低成本和能够增加系统的容量而备受关注。但是逆变器的并联会带来环流问题，环流不仅会降低系统效率，而且会使输出并网电流发生畸变。环流主要在零矢量中产生，通过双环控制实现环流抑制，外环在零序分量采用无差拍实现环流抑制，内环采用多载波消除零矢量的作用时间，环流能够得到非常好的抑制。在并网并联逆变系统中，电流控制器的结构和参数对系统稳定性和输出电流质量至关重要。电流环采用αβ静止坐标系下的比例谐振控制器，省去了复杂的坐标变换，从而使计算简单易实现。该方法不需要增加额外的硬件，能够较好地抑制环流和具有动态反应快等优点。通过仿真和实验验证了理论分析的正确性。 |
| 关键词: 逆变器并联 环流 PR控制器 多载波调制 |
| DOI：10.7667/PSPC151051 |
| 投稿时间：2015-06-24修订日期：2016-01-22 |
| 基金项目:河南省科技厅计划项目(162102210301);河南省教育厅高等学校重点科研项目(15A470019) |
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| Multicarrier PWM and PR control strategy of circulating current reduction for grid-connected converters |
| CHEN Suhua |
| (College of Electricity and Information Engineering, Xuchang University, Xuchang 461000, China) |
| Abstract: |
| The use of parallel three-phase converters has become more popular due to their simplicity, low cost, and expandability. However, the pulse width modulation (PWM) switching of parallel three-phase converters causes circulating current. The circulating current is mainly affected by the zero vectors. This paper proposes a multicarrier PWM for parallel three-phase converters. The multicarrier PWM can synthesize the desired output voltage without using zero vectors. Through the double loop control to realize circulation inhibition, outer ring in the zero sequence component circulation is realized by using no beat; the inner ring uses the carrier to eliminate the effect of zero vector more time, which can get very good restrain circulation. Furthermore, the structures and parameters of current controller are very important for the system’s stability and the output current’s quality in the grid-connected inverter application. The PR controller is used in the current loop which is in the αβ stationary reference frame. This method eliminates the complex coordinate transformation while making the simple calculation. And the method does not need to add additional hardware, which can suppress the circulation current well and have the advantages of quick dynamic response. Finally, simulation and experiment results are presented to prove the validity of the theoretical analysis. |
| Key words: parallel inverters circulating current PR controller multicarrier modulation |
