电流控制型储能变流器控制稳定性分析与谐波谐振抑制技术研究

储能变流器是储能系统平抑新能源电站功率波动和支撑电网调频调压功能的核心载体。对储能变流器关键运行控制技术特别是电流控制模式下的控制策略进行研究，提出了电流内环无静差跟踪控制策略，建立了PI控制器比例、积分关键控制参数最佳阻尼比优化设计方法。基于开环幅相频率特性和开环对数频率特性方法，构建计及储能变流器电流内环的开环频域模型。通过Bode稳定判据，定量分析了不同电流内环比例系数、积分参数以及变流器阻感参数变化对储能变流器控制稳定性的影响，并采用Nyquist稳定判据对比验证，在实时数字仿真试验平台（RT-LAB）开展储能变流器并网测试，不同比例系数和积分系数下的并网系统均保持稳定。基于滤波器的输入电压到输出电流的传递函数，发现储能变流器存在谐波谐振问题，提出基于电容电流反馈的有源阻尼谐振抑制策略，有效消除谐波谐振影响。分析结果表明，所设计的储能变流器及其谐波谐振抑制策略，具备鲁棒性，能够为大型新能源电站建设提供有力支撑。

Control Stability Analysis and Research on Harmonic Resonance Suppression Technolgy of Current-Control Type Energy Storage Converter

The energy storage converter is the core carrier of the energy storage system to smooth the power fluctuations of renewable energy generation and to support the regulation of frequency and voltage. The key operation control technology of energy storage converter, especially the control strategy under current-control mode, is investigated. The tracking control strategy without static error of current inner loop is proposed. The design method of the PI control key parameters based on optimal damping ratio is proposed. Based on open-loop amplitude-phase frequency characteristic and open-loop logarithmic frequency characteristic method, the open-loop frequency domain model of the current inner loop of the energy storage converter is constructed. Through the Bode stability criterion, the influence of different current inner loop proportional coefficient, integral coefficient and converter resistance parameter change on the control stability of the energy storage converter is quantitatively analysed. At meanwhile, the Nyquist stability criterion is used to verify the results. The grid-connected test of the energy storage converter is carried out on the real time labratory (RT-LAB) platform. The grid-connected system remains stable under the different proportional coefficient and integral coefficient. Based on the transfer function of filter capacitor input voltage to output current, the problem of harmonic resonance is found. The active damping resonant suppression strategy based on capacitor current feedback is proposed, which can effectively eliminate the effect of harmonic resonance. The analysis results indicate that the proposed current-control type energy storage converter and its harmonic resonance suppression method is robustness for supporting development of renewable energy generation.