Insulation failure significantly contributes to the unpredictable shutdown of power equipment.Compared to the partial discharge and high-frequency(HF)injection methods,the HF common-mode(CM)leakage current method offe...Insulation failure significantly contributes to the unpredictable shutdown of power equipment.Compared to the partial discharge and high-frequency(HF)injection methods,the HF common-mode(CM)leakage current method offers a non-intrusive and highly sensitive alternative.However,the detection of HF CM currents is susceptible to interference from differential-mode(DM)currents,which exhibit high-amplitude and multifrequency components during normal operation.To address this challenge,this paper proposes a double-ring current sensor based on the principle of magnetic shielding for inverter-fed machine winding insulation monitoring.The inner ring harnesses the magnetic aggregation effect to isolate the DM current magnetic field,whereas the outer ring serves as the magnetic core of the Rogowski current sensor,enabling HF CM current monitoring.First,the magnetic field distributions of the CM and DM currents were analyzed.Then,a correlation between the sensor parameters and signal-to-noise ratio of the target HF CM current was established.Finally,an experimental study was conducted on a 3-kW PMSM for verification.The results indicate that the proposed double-ring HF CM sensor can effectively mitigate DM current interference.Compared to a single-ring sensor,a reduction of approximately 40%in the DM component was achieved,which significantly enhanced the precision of online insulation monitoring.展开更多
Rectifiers with high efficiency and high power density are crucial to the stable and efficient power supply of 5G communication base stations,which deserves in-depth investigation.In general,there are two key problems...Rectifiers with high efficiency and high power density are crucial to the stable and efficient power supply of 5G communication base stations,which deserves in-depth investigation.In general,there are two key problems to be addressed:supporting both alternating current(AC)and direct current(DC)input,and minimizing the common-mode voltage as well as leakage current for safety reasons.In this paper,a hybrid five-level single-phase rectifier is proposed.A five-level topology is adopted in the upper arm,and a half-bridge diode topology is adopted in the lower arm.A dual closed-loop control strategy and a flying capacitor voltage regulation method are designed accordingly so that the compatibility of both AC and DC input is realized with low common voltage and small passive devices.Simulation and experimental results demonstrate the effectiveness and performance of the proposed rectifier.展开更多
基金supported in part by the National Natural Science Foundation of China under Grant 51907116in part sponsored by Natural Science Foundation of Shanghai 22ZR1425400sponsored by Shanghai Rising-Star Program 23QA1404000。
文摘Insulation failure significantly contributes to the unpredictable shutdown of power equipment.Compared to the partial discharge and high-frequency(HF)injection methods,the HF common-mode(CM)leakage current method offers a non-intrusive and highly sensitive alternative.However,the detection of HF CM currents is susceptible to interference from differential-mode(DM)currents,which exhibit high-amplitude and multifrequency components during normal operation.To address this challenge,this paper proposes a double-ring current sensor based on the principle of magnetic shielding for inverter-fed machine winding insulation monitoring.The inner ring harnesses the magnetic aggregation effect to isolate the DM current magnetic field,whereas the outer ring serves as the magnetic core of the Rogowski current sensor,enabling HF CM current monitoring.First,the magnetic field distributions of the CM and DM currents were analyzed.Then,a correlation between the sensor parameters and signal-to-noise ratio of the target HF CM current was established.Finally,an experimental study was conducted on a 3-kW PMSM for verification.The results indicate that the proposed double-ring HF CM sensor can effectively mitigate DM current interference.Compared to a single-ring sensor,a reduction of approximately 40%in the DM component was achieved,which significantly enhanced the precision of online insulation monitoring.
文摘Rectifiers with high efficiency and high power density are crucial to the stable and efficient power supply of 5G communication base stations,which deserves in-depth investigation.In general,there are two key problems to be addressed:supporting both alternating current(AC)and direct current(DC)input,and minimizing the common-mode voltage as well as leakage current for safety reasons.In this paper,a hybrid five-level single-phase rectifier is proposed.A five-level topology is adopted in the upper arm,and a half-bridge diode topology is adopted in the lower arm.A dual closed-loop control strategy and a flying capacitor voltage regulation method are designed accordingly so that the compatibility of both AC and DC input is realized with low common voltage and small passive devices.Simulation and experimental results demonstrate the effectiveness and performance of the proposed rectifier.
