Hybrid AC/DC distribution networks are promising candidates for future applications due to their rapid advancement in power electronics technology.They use interface converters(IFCs)to link DC and AC distribution netw...Hybrid AC/DC distribution networks are promising candidates for future applications due to their rapid advancement in power electronics technology.They use interface converters(IFCs)to link DC and AC distribution networks.However,the networks possess drawbacks with AC voltage and frequency offsets when transferring from grid-tied to islanding modes.To address these problems,this paper proposes a simple but effective strategy based on the reverse droop method.Initially,the power balance equation of the distribution system is derived,which reveals that the cause of voltage and frequency offsets is the mismatch between the IFC output power and the rated load power.Then,the reverse droop control is introduced into the IFC controller.By using a voltage-active power/frequency-reactive power(U-P/f-Q)reverse droop loop,the IFC output power enables adaptive tracking of the rated load power.Therefore,the AC voltage offset and frequency offset are suppressed during the transfer process of operational modes.In addition,the universal parameter design method is discussed based on the stability limitations of the control system and the voltage quality requirements of AC critical loads.Finally,simulation and experimental results clearly validate the proposed control strategy and parameter design method.展开更多
To realize a high-power density capacitive coupler for miniaturized rotary application,a parameter design method is proposed in this article.Since a capacitive coupler is composed of metal plates and external capacito...To realize a high-power density capacitive coupler for miniaturized rotary application,a parameter design method is proposed in this article.Since a capacitive coupler is composed of metal plates and external capacitors,limitations include two parts.One is air breakdown voltage limitation of metal plates,and the other one is withstanding voltage limitation of external capacitors.To quantify voltage limitation,voltage stress is analyzed.Then,an optimal design method for external capacitors is proposed,realizing minimum voltage stress and optimal load condition,simultaneously.Using an optimal external capacitor,a parameter design method is proposed to maximize power density.In which,the air breakdown voltage limitation determines the range of resonant frequency.Then,the withstanding voltage limitation determines specific resonant frequency and composition of external capacitors.Experimental results show the proposed method can realize DC-DC efficiency of 91.35% and power density of 423 W/in^(3)under a 1 kW output condition.展开更多
基金This work was supported by the National Key R&D Program of China(2018YFB0904700).
文摘Hybrid AC/DC distribution networks are promising candidates for future applications due to their rapid advancement in power electronics technology.They use interface converters(IFCs)to link DC and AC distribution networks.However,the networks possess drawbacks with AC voltage and frequency offsets when transferring from grid-tied to islanding modes.To address these problems,this paper proposes a simple but effective strategy based on the reverse droop method.Initially,the power balance equation of the distribution system is derived,which reveals that the cause of voltage and frequency offsets is the mismatch between the IFC output power and the rated load power.Then,the reverse droop control is introduced into the IFC controller.By using a voltage-active power/frequency-reactive power(U-P/f-Q)reverse droop loop,the IFC output power enables adaptive tracking of the rated load power.Therefore,the AC voltage offset and frequency offset are suppressed during the transfer process of operational modes.In addition,the universal parameter design method is discussed based on the stability limitations of the control system and the voltage quality requirements of AC critical loads.Finally,simulation and experimental results clearly validate the proposed control strategy and parameter design method.
基金supported in part by the National Natural Science Foundation of China under Grant 52277185.
文摘To realize a high-power density capacitive coupler for miniaturized rotary application,a parameter design method is proposed in this article.Since a capacitive coupler is composed of metal plates and external capacitors,limitations include two parts.One is air breakdown voltage limitation of metal plates,and the other one is withstanding voltage limitation of external capacitors.To quantify voltage limitation,voltage stress is analyzed.Then,an optimal design method for external capacitors is proposed,realizing minimum voltage stress and optimal load condition,simultaneously.Using an optimal external capacitor,a parameter design method is proposed to maximize power density.In which,the air breakdown voltage limitation determines the range of resonant frequency.Then,the withstanding voltage limitation determines specific resonant frequency and composition of external capacitors.Experimental results show the proposed method can realize DC-DC efficiency of 91.35% and power density of 423 W/in^(3)under a 1 kW output condition.
