dq impedance measurement method for grid-connected converters based on single-phase harmonic injection
The stability analysis of new energy grid-connected systems typically employs impedance analysis method,which necessitates determining the dq impedance of grid-connected converters.How-ever,traditional impedance measurement methods often suffer from low measurement efficiency and high requirements for measurement equipment.To address these challenges,this study proposes a dq impedance measurement method for grid-connected converter based on the principle of single-phase harmonic voltage injection.First,the principle of dq impedance measurement for grid-connected con-verters based on harmonic injection is analyzed,clarifying that two independent sets of disturbance voltages and currents are required for dq impedance measurement.Then,the principle of single-phase harmonic injection dq impedance measurement is given.Combined with the analysis of the relationship between injection frequencies during multi-frequency point measurement,the study designs the mea-surement steps for single-phase harmonic injection dq impedance measurement for both single-frequency point and multi-frequency point impedance measurements of grid-connected converters.Finally,simulations and experimental measurements are conducted to evaluate the impedance of grid-connected converters under single current loop control and voltage-current double loop control.The re-sults show that,compared with the traditional measurement method of three-phase harmonic injec-tion,the single-phase harmonic injection dq impedance measurement method reduces the require-ments for harmonic injection equipment while maintaining measurement accuracy.Additionally,when measuring at multiple frequency points,the measurement times of the single-phase harmonic injection method are less than that of the traditional three-phase harmonic injection method,which reduces the measurement amount and improves the measurement efficiency.
power electronics and electric drivegrid-connected converterharmonic injectionimped-ance measurement
万方数据
维普
