| 引用本文: | 叶吉亮,李岚,刘海霞,等.电网电压不平衡及谐波状态下的并网逆变器控制策略[J].电力系统保护与控制,2018,46(6):113-119. |
| YE Jiliang,LI Lan,LIU Haixia,et al.Control strategy of grid-connected inverter under unbalanced and harmonic voltage condition[J].Power System Protection and Control,2018,46(6):113-119 |
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| 摘要: |
| 为了提高并网逆变器在电网电压不平衡及谐波状态下的适应能力，使其能够输出高质量的并网电流，需对传统并网逆变器控制策略进行改进。以αβ坐标系下LCL型并网逆变器模型为研究对象，提出一种基于准比例谐振(QPR)和电网电压前馈的控制策略。首先，分析了并网电流与其给定值和电网电压之间的关系，得出稳态误差及扰动分量产生的原因。然后，通过QPR控制策略来实现并网电流的无静差控制，引入电网电压前馈控制来抑制电网扰动对并网电流的直接影响。同时，为了提高传统锁相环在电网电压非理想情况下锁相精度及谐波抑制能力，对传统锁相环做进一步改进，以提高锁相环抗扰能力。最后，在Matlab/Simulink中进行仿真验证，仿真结果表明该控制策略能够在电网电压不平衡及谐波状态下得到高质量的并网电流，使逆变器能高效稳定运行，验证了该控制方法的有效性和正确性。 |
| 关键词: 电网电压不平衡 LCL并网逆变器 QPR控制器 电网电压前馈 改进型锁相环 |
| DOI：10.7667/PSPC170253 |
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| Control strategy of grid-connected inverter under unbalanced and harmonic voltage condition |
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YE Jiliang,LI Lan,LIU Haixia,WANGYulong
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(College of Electrical and Power Engineering, Taiyuan University of Technology, Taiyuan 030024, China)
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| Abstract: |
| In order to improve the adaptability of the grid-connected inverter under the unbalanced and harmonic voltage condition and make it produce high quality grid-connected current, it is necessary to improve the traditional grid-connected inverter control strategy. This paper focuses on the model of LCL grid connected inverter in a αβ coordinate system, and presents a control strategy of Quasi Proportional Resonant (QPR) and grid voltage feedforward. Firstly, the paper analyzes the relationship between the grid-connected current and its given value & grid voltage to get the reason why the steady-state error and disturbance component perturbation component produced. Then, a QPR control strategy is introduced to realize the zero-steady-state error control of grid-connected current and the voltage feedforward control is added to suppress the direct effect of grid disturbance on grid-connected current. At the same time, an improved phase-locked loop control strategy is also introduced to improve the accuracy and the ability of harmonic suppression of traditional one under non-ideal grid voltage state, thereby enhancing phase-locked loop anti-interference. Finally, the simulation results based on Matlab/Simulink show that the proposed control strategy not only gets high-quality grid-connected current under the status of unbalanced and harmonic grid voltage, but also ensures the efficient and stable operation of the inverter, verifying its validity and correctness. |
| Key words: unbalanced grid voltage LCL grid-connected inverter QPR controller grid voltage feed-forward improved phase-locked loop |
