Grid impedance and phase-locked loop(PLL)are critical factors for the stability of the grid-connected inverters(GCIs)in a weak grid.They are the positive feedback control loops formed by PLL in the GCI with grid imped...Grid impedance and phase-locked loop(PLL)are critical factors for the stability of the grid-connected inverters(GCIs)in a weak grid.They are the positive feedback control loops formed by PLL in the GCI with grid impedance.It is prone to GCI instability,especially in the case of the higher PLL bandwidth.A novel impedance-phase and magnitude control strategy is proposed to improve stability of GCI with different grid impedance.Moreover,a detailed design of control loop and parameter calculation for the impedance-phase and magnitude control strategy are introduced.First,PLL output impedance is reshaped to broaden the frequency range of the GCI phase-frequency characteristic curve above the−90°line towards the low-frequency band.In addition,current loop output impedance is reshaped to maintain the phase margin(PM)of the GCI near to 45°.Meanwhile,the magnitude of GCI output impedance is also increased significantly.Stability of the GCI in a weak grid is enhanced by adopting the proposed control strategy.Simulation and experimental results verify the analysis and the proposed method.展开更多
The present paper proposes an optimization design method for the Doherty output matching network(OMN)using impedance–phase hybrid objective function constraints,which possesses the capability of enhancing the efficie...The present paper proposes an optimization design method for the Doherty output matching network(OMN)using impedance–phase hybrid objective function constraints,which possesses the capability of enhancing the efficiency consistency of the Doherty power amplifier(DPA)using integrated enhancing reactance(IER)during the back-off power(BOP)range.By calculating the desired reactance for an extended BOP range and combining it with the two-impedance matching method,the S-parameters of the OMN are obtained.Meanwhile,the impedance and phase constraints of the OMN are proposed to narrow the distribution range of the IER.Furthermore,a fragmenttype structure is employed in the OMN optimization so as to enhance the flexibility of the circuit optimization design.To validate the proposed method,a 1.7–2.5 GHz symmetric DPA with a large BOP range was designed and fabricated.Measurement results demonstrate that across the entire operating frequency band,the saturated output power is>44 dBm,and the efficiency ranges from 45%to 55%at a 9-dB BOP.展开更多
基金supported in part by the Leading talents of scientific and technological innovation in Hunan Province under Grant(No.2019RS3014)the National Natural Science Foundation of China under Grant(No.51907057)。
文摘Grid impedance and phase-locked loop(PLL)are critical factors for the stability of the grid-connected inverters(GCIs)in a weak grid.They are the positive feedback control loops formed by PLL in the GCI with grid impedance.It is prone to GCI instability,especially in the case of the higher PLL bandwidth.A novel impedance-phase and magnitude control strategy is proposed to improve stability of GCI with different grid impedance.Moreover,a detailed design of control loop and parameter calculation for the impedance-phase and magnitude control strategy are introduced.First,PLL output impedance is reshaped to broaden the frequency range of the GCI phase-frequency characteristic curve above the−90°line towards the low-frequency band.In addition,current loop output impedance is reshaped to maintain the phase margin(PM)of the GCI near to 45°.Meanwhile,the magnitude of GCI output impedance is also increased significantly.Stability of the GCI in a weak grid is enhanced by adopting the proposed control strategy.Simulation and experimental results verify the analysis and the proposed method.
基金supported by the National Natural Science Foundation of China(Nos.62171204,62001192,and 62171129)。
文摘The present paper proposes an optimization design method for the Doherty output matching network(OMN)using impedance–phase hybrid objective function constraints,which possesses the capability of enhancing the efficiency consistency of the Doherty power amplifier(DPA)using integrated enhancing reactance(IER)during the back-off power(BOP)range.By calculating the desired reactance for an extended BOP range and combining it with the two-impedance matching method,the S-parameters of the OMN are obtained.Meanwhile,the impedance and phase constraints of the OMN are proposed to narrow the distribution range of the IER.Furthermore,a fragmenttype structure is employed in the OMN optimization so as to enhance the flexibility of the circuit optimization design.To validate the proposed method,a 1.7–2.5 GHz symmetric DPA with a large BOP range was designed and fabricated.Measurement results demonstrate that across the entire operating frequency band,the saturated output power is>44 dBm,and the efficiency ranges from 45%to 55%at a 9-dB BOP.
