Demagnetization behavior of Halbach magnetized compensated pulsed alternator(CPA)is studied by using finite element method(FEM)under the different demagnetization factors in this paper.The effect of armature reaction ...Demagnetization behavior of Halbach magnetized compensated pulsed alternator(CPA)is studied by using finite element method(FEM)under the different demagnetization factors in this paper.The effect of armature reaction magnetic field and thermal rise on demagnetization of PMs is analyzed.This paper investigates the effect of different demagnetization factors on magnetic field distribution,load current,and no-load phase voltage.A series of dynamic demagnetization points in Halbach array permanent magnet(PM)are evaluated to search the worst working point.Partial demagnetization risk can be represented by the worst working point,and the global demagnetization of the PM is represented by the no-load phase voltage characteristics after discharge.The research results demonstrated that the compensation shield with a certain thickness can increase the discharge current and weaken the demagnetization influence of armature reaction.The demagnetization effect of armature reaction on PMs at high temperatures will be strengthened.展开更多
A hybrid bidirectional DC/DC converter(BDC)is proposed as the fundamental DC/DC module in solid-state transformers,which combines a bidirectional LLC converter and a dual-active-bridge(DAB)converter.Integrated with a ...A hybrid bidirectional DC/DC converter(BDC)is proposed as the fundamental DC/DC module in solid-state transformers,which combines a bidirectional LLC converter and a dual-active-bridge(DAB)converter.Integrated with a mutual control scheme,both parts of this hybrid BDC can be unified into an interdependent community.In this hybrid BDC,the LLC converter supports the output voltage and improves stability by working at the resonant frequency mode and the DAB converter enhances the BDC power capability by controlling the LLC output current constant.The BDC can achieve the full-load-range soft switching of all active switches by designing the auxiliary inductor of LLC and the minimum output current of DAB.By comparing to the single DAB,the proposed BDC has the higher phase and gain margin which means the BDC improved the relative stability based on Nyquist criterion.To solve the bidirectional power control problem,a dead-band voltage control logic is adopted which can determine the BDC’s power direction based on the output voltage change.A 200 V experimental system has verified the aforementioned features and functions of the BDC.展开更多
基金This work was supported by the Natural Science Foundation of China under Grant 51307031 and part by the Natural Science Foundation of Heilongjiang Province under Grant E2018034 and China Postdoctoral Science Foundation funded project under Grant 2019M651185.
文摘Demagnetization behavior of Halbach magnetized compensated pulsed alternator(CPA)is studied by using finite element method(FEM)under the different demagnetization factors in this paper.The effect of armature reaction magnetic field and thermal rise on demagnetization of PMs is analyzed.This paper investigates the effect of different demagnetization factors on magnetic field distribution,load current,and no-load phase voltage.A series of dynamic demagnetization points in Halbach array permanent magnet(PM)are evaluated to search the worst working point.Partial demagnetization risk can be represented by the worst working point,and the global demagnetization of the PM is represented by the no-load phase voltage characteristics after discharge.The research results demonstrated that the compensation shield with a certain thickness can increase the discharge current and weaken the demagnetization influence of armature reaction.The demagnetization effect of armature reaction on PMs at high temperatures will be strengthened.
文摘A hybrid bidirectional DC/DC converter(BDC)is proposed as the fundamental DC/DC module in solid-state transformers,which combines a bidirectional LLC converter and a dual-active-bridge(DAB)converter.Integrated with a mutual control scheme,both parts of this hybrid BDC can be unified into an interdependent community.In this hybrid BDC,the LLC converter supports the output voltage and improves stability by working at the resonant frequency mode and the DAB converter enhances the BDC power capability by controlling the LLC output current constant.The BDC can achieve the full-load-range soft switching of all active switches by designing the auxiliary inductor of LLC and the minimum output current of DAB.By comparing to the single DAB,the proposed BDC has the higher phase and gain margin which means the BDC improved the relative stability based on Nyquist criterion.To solve the bidirectional power control problem,a dead-band voltage control logic is adopted which can determine the BDC’s power direction based on the output voltage change.A 200 V experimental system has verified the aforementioned features and functions of the BDC.
