The self-excited DC air circuit breaker(SE-DCCB)has been widely used in urban rail transit due to its excellent stability.It can realize forward and reverse interruption,but has difficulty interrupting small currents ...The self-excited DC air circuit breaker(SE-DCCB)has been widely used in urban rail transit due to its excellent stability.It can realize forward and reverse interruption,but has difficulty interrupting small currents due to the phenomenon of arc root sticking at the entrance of the arc chamber in the splitting process,which is known as arc root stagnation.A coupling model of the self-excited magnetic field and magnetohydrodynamics is established for the SE-DCCB with the traditional structure.The magnetic field,temperature and airflow distribution in the arc chamber are investigated with an interrupting current of 150 A.The simulation results show that the direction and magnitude of the magnetic blowout force are the dominant factors in the arc root stagnation.The local high temperature of the arc chamber due to arc root stagnation increases the obstruction effect of the airflow vortex on the arc root movement,which significantly increases the arc duration time of small current interruption.Based on the research,the structure of the magnetic conductance plate of the actual product is improved,which can improve the direction and magnitude of the magnetic blowout force at the arc root so as to restrain the development of the airflow vortex effectively and solve the problem of arc root stagnation when the small current is interrupted.The simulation results show that the circuit breaker with improved structure has a better performance for a small current interruption range from 100 A to 350 A.展开更多
随着国家对新型节能科技的重点扶持以及安全经营的高度重视,商业厨房中明火烹调的方式逐渐被节能环保、安全系数高的电磁加热所取代。针对Middleby公司的商用电磁保温桶项目,设计实现了温度可调、加热保温自动化、超温及干锅自动断电保...随着国家对新型节能科技的重点扶持以及安全经营的高度重视,商业厨房中明火烹调的方式逐渐被节能环保、安全系数高的电磁加热所取代。针对Middleby公司的商用电磁保温桶项目,设计实现了温度可调、加热保温自动化、超温及干锅自动断电保护的智能化加热产品。在商用电磁保温桶的开发设计过程中,作为后级电路的驱动电路,自激振荡电路是整个系统中必不可少的的环节。为了设计保温电磁设备工作电路中使用的15 k Hz稳定脉冲的多谐自激振荡电路,分析了传统自激振荡电路的原理与不足。通过增加反馈电路与延时电路,设计了性能稳定的对称多谐自激振荡电路。通过软件仿真及实际电路测试,将理论值与实际值进行比较分析。试验结果表明,所设计的对称多谐自激振荡电路可以提高系统稳定性,杜绝程序跑飞的可能性,且电路结构简单、成本低,适用于低功率应用场合。展开更多
高压直流输电作为最为经济的能源输送方式,具有输送容量大、传输距离远、损耗低等多种优势,±400 k V青藏直流工程的建设实现了西北与西藏电网的联网,优化了能源资源配置。直流系统使用直流转换开关可以获得多种功能和运行的灵活性...高压直流输电作为最为经济的能源输送方式,具有输送容量大、传输距离远、损耗低等多种优势,±400 k V青藏直流工程的建设实现了西北与西藏电网的联网,优化了能源资源配置。直流系统使用直流转换开关可以获得多种功能和运行的灵活性。文中以研发直流转换开关为目标,阐述了无源型基本原理,从产品的总体结构、断路器的电弧电压与直流开断的关系、自激振荡回路的元件设计及工程设计等方面进行了研究。所研发的直流转换开关通过了试验验证,并已应用于青藏直流输电工程的拉萨换流站。展开更多
基金supported by National Natural Science Foundation of China(No.51977132)the Key Special Science and Technology Project of Liaoning Province(No.2020JH1/10100012)the General Program of the Education Department of Liaoning Province(No.LJKZ0126).
文摘The self-excited DC air circuit breaker(SE-DCCB)has been widely used in urban rail transit due to its excellent stability.It can realize forward and reverse interruption,but has difficulty interrupting small currents due to the phenomenon of arc root sticking at the entrance of the arc chamber in the splitting process,which is known as arc root stagnation.A coupling model of the self-excited magnetic field and magnetohydrodynamics is established for the SE-DCCB with the traditional structure.The magnetic field,temperature and airflow distribution in the arc chamber are investigated with an interrupting current of 150 A.The simulation results show that the direction and magnitude of the magnetic blowout force are the dominant factors in the arc root stagnation.The local high temperature of the arc chamber due to arc root stagnation increases the obstruction effect of the airflow vortex on the arc root movement,which significantly increases the arc duration time of small current interruption.Based on the research,the structure of the magnetic conductance plate of the actual product is improved,which can improve the direction and magnitude of the magnetic blowout force at the arc root so as to restrain the development of the airflow vortex effectively and solve the problem of arc root stagnation when the small current is interrupted.The simulation results show that the circuit breaker with improved structure has a better performance for a small current interruption range from 100 A to 350 A.
文摘随着国家对新型节能科技的重点扶持以及安全经营的高度重视,商业厨房中明火烹调的方式逐渐被节能环保、安全系数高的电磁加热所取代。针对Middleby公司的商用电磁保温桶项目,设计实现了温度可调、加热保温自动化、超温及干锅自动断电保护的智能化加热产品。在商用电磁保温桶的开发设计过程中,作为后级电路的驱动电路,自激振荡电路是整个系统中必不可少的的环节。为了设计保温电磁设备工作电路中使用的15 k Hz稳定脉冲的多谐自激振荡电路,分析了传统自激振荡电路的原理与不足。通过增加反馈电路与延时电路,设计了性能稳定的对称多谐自激振荡电路。通过软件仿真及实际电路测试,将理论值与实际值进行比较分析。试验结果表明,所设计的对称多谐自激振荡电路可以提高系统稳定性,杜绝程序跑飞的可能性,且电路结构简单、成本低,适用于低功率应用场合。
文摘高压直流输电作为最为经济的能源输送方式,具有输送容量大、传输距离远、损耗低等多种优势,±400 k V青藏直流工程的建设实现了西北与西藏电网的联网,优化了能源资源配置。直流系统使用直流转换开关可以获得多种功能和运行的灵活性。文中以研发直流转换开关为目标,阐述了无源型基本原理,从产品的总体结构、断路器的电弧电压与直流开断的关系、自激振荡回路的元件设计及工程设计等方面进行了研究。所研发的直流转换开关通过了试验验证,并已应用于青藏直流输电工程的拉萨换流站。
