基于LMT信号的微电网交流器输出阻抗校正方法

Correction method of output impedance of AC in microgrid based on LMT signal

微电网交流器输出阻抗校正方法难以抑制交互过程产生的谐波谐振,导致失稳。为此,提出基于LMT信号的微电网交流器输出阻抗校正方法,分析下垂控制变闭环输出阻抗,计算输出功率调节转换器的额定电流小扰动能量,建立传递函数实现阻抗分析。通过LMT信号原理重新定义所有数据格式,计算微电网交流器阻抗数值,利用LMT信号反演实现阻抗校正。实验结果表明,校正前的电压峰值为375 V,峰值电流为400 A,校正后的波形均匀稳定,且峰值与校正前基本一致,因此基于LMT信号的微电网交流器输出阻抗校正方法能保证校正过程的稳定性。

The output impedance correction method of AC micro grid is difficult to suppress the harmonic resonance generated in the interaction process,which leads to instability.Therefore,the output impedance correction method of micro grid AC based on LMT signal is proposed.The output impedance of droop control variable closed loop is analyzed,the small disturbance energy of rated current of output power regulating converter is calculated,and the transfer function is established to realize impedance analysis.All data formats are redefined based on LMT signal principle,impedance values of microgrid AC are calculated,and impedance correction is realized by inversion of LMT signal.The experimental results show that the voltage peak value before correction is 375 V,and the peak current is 400 A.The waveform after correction is uniform and stable,and the peak value is basically consistent with that before correction.Therefore,the output impedance correction method of micro grid AC based on LMT signal can ensure the stability of the correction process.