不对称电网电压下VSC-HVDC模型预测直接功率控制

发布时间：2018-08-19 10:06

【摘要】：不对称电网电压下采用传统定义的瞬时有功和无功实现直接功率控制时,会产生较多的电流谐波,导致交流电流波形发生严重的畸变。为此,引入新型无功代替传统无功。对比了分别采用传统无功和新型无功时的区别,并定性分析了采用传统无功产生电流谐波的原因。基于有功和新型无功建立了三电平电压源换流器高压直流输电(high voltage direct current transmission based on voltage source converter,VSC-HVDC)功率模型,提出模型预测直接功率控制策略(model predictive direct power control,MPDPC),实现了不对称电网电压下有功和新型无功波动的有效抑制和直流侧电容电压平衡,并保证了良好的电流波形质量。基于新型无功的MPDPC可以适应对称和不对称电网电压,实现了功率的直接控制,避免了电压、电流的正负序分解和功率补偿策略。在PSCAD/EMTDC中搭建两端三电平VSC-HVDC仿真系统,仿真结果验证了所提策略的正确性和有效性。
[Abstract]:When the traditional definition of instantaneous active and reactive power is used to realize direct power control under asymmetric grid voltage, there will be more current harmonics, resulting in serious distortion of AC current waveform. Therefore, a new type of reactive power is introduced to replace the traditional reactive power. The difference between the traditional reactive power and the new reactive power is compared, and the reason of the current harmonic generation using the traditional reactive power is analyzed qualitatively. Based on active power and new reactive power, a three-level voltage source converter (high voltage direct current transmission based on voltage source convertor VSC-HVDC) power model is established. A model predictive direct power control strategy (model predictive direct power control MPDPC) is proposed, which can effectively suppress the active and new reactive power fluctuations under asymmetric grid voltage and balance the capacitance voltage at the DC side, and ensure the good quality of the current waveform. MPDPC based on new reactive power can adapt to symmetric and asymmetric grid voltage, realize direct power control, avoid the positive and negative sequence decomposition of voltage and current and power compensation strategy. A three-level VSC-HVDC simulation system is built in PSCAD/EMTDC. The simulation results verify the correctness and effectiveness of the proposed strategy.
【作者单位】：中国矿业大学(北京)机电与信息工程学院;
【基金】：中央高校基本科研业务费资助(2017QJ05)~~
【分类号】：TM721.1

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