Improved DSOGI-PLL for synchronizing frequency detection of mine power grid voltage
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摘要: 针对双二阶广义积分器锁相环(DSOGI-PLL)在矿井电网电压含多次谐波或存在直流偏置的情况下提取电压同步信号存在频率、相位误差的问题,提出了一种改进型DSOGI-PLL,从频率调节、直流偏置、谐波检测3个方面对DSOGI-PLL进行改进。构造频率自适应调节单元,实时监测矿井电网频率变化来自动调节DSOGI-PLL的谐振频率,实现DSOGI-PLL的频率自适应功能,以提高频率检测精准度,优化动态响应性能;将积分反馈补偿环节应用于基于二阶广义积分器的正交信号发生器(SOGI-QSG),以消除直流分量对检测结果的影响;提出一种多DSOGI并联的交叉反馈结构,该结构下,每个DSOGI的输入信号不含其余DSOGI检测到的谐波成分,削弱了各次谐波分量相互之间的影响。Matlab仿真结果表明,改进型DSOGI-PLL能在矿井电网电压有严重干扰的情况下,完成对电网电压频率和相角的精准检测和跟踪锁定。Abstract: In view of problems that there are frequency and phase errors in extracting voltage synchronization signals of DSOGI-PLL with multiple harmonics or DC bias in mine grid, an improved DSOGI-PLL was proposed to improve DSOGI-PLL from three aspects: frequency regulation, DC bias and harmonic detection.Frequency adaptive adjustment unit is constructed to automatically adjust resonant frequency of DSOGI-PLL through real-time monitoring of frequency change of mine power grid, so as to realize frequency adaptive function of DSOGI-PLL, which can improve accuracy of frequency detection and optimize dynamic response performance.Integral feedback compensation is applied to the second-order generalized integrator-quadrature signals generator(SOGI-QSG) to remove the influence of direct-current component on the test results.Cross feedback structure of multiple DSOGIs in parallel is proposed. In this structure, the input signal of each DSOGI does not contain harmonic components detected by other DSOGIs, which weakens influence of each harmonic component on each other. Matlab simulation results show that the improved DSOGI-PLL can complete accurate detection and tracking lock of frequency and phase angle of the grid voltage when the mine grid voltage has serious interference.
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