This paper presents an auto-tuning method for a proportion plus integral（PI） controller for permanent magnet synchronous motor（PMSM） drives, which is supposed to be embedded in electro-mechanical actuator（EMA） c...This paper presents an auto-tuning method for a proportion plus integral（PI） controller for permanent magnet synchronous motor（PMSM） drives, which is supposed to be embedded in electro-mechanical actuator（EMA） control module in aircraft. The method, based on a relay feedback with variable delay time, explores different critical points of the system frequency response.The Nyquist points of the plant can then be derived from the delay time and filter time constant.The coefficients of the PI controller can then be obtained by calculation while shifting the Nyquist point to a specific position to obtain the required phase margin. The major advantage of the autotuning method is that it can provide a series of tuning results for different system bandwidths and damping ratios, corresponding to the specification for delay time and phase margin. Simulation and experimental results for the PMSM controller verify the performance of both the current loop and the speed loop auto-tuning.展开更多
三维城市模型是智慧城市与数字孪生城市的核心内容。IFC(industry foundation classes)标准构建的建筑信息模型(building information model,BIM)为城市空间规划和建筑设计提供了丰富而精细的城市三维模型数据。由于标准的差异,BIM无法...三维城市模型是智慧城市与数字孪生城市的核心内容。IFC(industry foundation classes)标准构建的建筑信息模型(building information model,BIM)为城市空间规划和建筑设计提供了丰富而精细的城市三维模型数据。由于标准的差异,BIM无法与三维地理信息系统无缝集成和交互应用,极大地限制了IFC标准BIM的应用优势。本文挖掘IFC、CityGML(city geography markup language)标准三维建筑模型的语义表达差异,提出BIM源模型向不同细节层次(level of detail,LOD)层级模型的几何转换方法;构建一套完整的转换流程,实现IFC标准BIM向CityGML标准三维建筑模型的几何转换;设计并开发转换原型系统。研究表明:本方法及实现流程能够有效实现IFC-BIM模型向CityGML-BIM模型的不同LOD层级的转换,且对多数单体模型相当实用;转换后模型未见错误与偏差,视觉效果良好;具备灵活性,可根据不同模型的转换进行调整。研究成果为BIM与地理信息系统的集成应用提供了新思路,为智慧城市与数字孪生开辟了一种新的数据来源通道。展开更多
An overview of recent advances in digital control of low-to medium-power DC/DC switching converters is presented.Traditionally,analog electronics methods have dominated in controlling such DC/DC converters.However,wit...An overview of recent advances in digital control of low-to medium-power DC/DC switching converters is presented.Traditionally,analog electronics methods have dominated in controlling such DC/DC converters.However,with the steadily decreasing cost of ICs,the feasibility of digitally controlled DC/DC switching converters has increased sig-nificantly.This paper outlines a sample of digital solutions for DC/DC switching converters to enhance the performance of DC/DC switching converters.Furthermore,latest research activities pertaining to applications for steady-state and dy-namic performance improvement,such as efficiency optimization,controller auto tuning,and capacitor charge balance control,is discussed.These applications demonstrate the significant advantages and potentials of digital control.展开更多
传统的高压直流输电(high voltage direct current,HVDC)系统一般在换流站交流网侧布置滤波兼无功补偿装置,谐波与无功功率通过换流变压器回馈网侧时会对变压器产生不良的影响。作者基于自耦补偿与谐波屏蔽的换流变压器,针对某实际的HVD...传统的高压直流输电(high voltage direct current,HVDC)系统一般在换流站交流网侧布置滤波兼无功补偿装置,谐波与无功功率通过换流变压器回馈网侧时会对变压器产生不良的影响。作者基于自耦补偿与谐波屏蔽的换流变压器,针对某实际的HVDC模拟系统,提出了与该变压器配套的滤波装置的接线方案,并将外罚函数法和遗传算法相结合,对上述滤波装置进行优化设计,建立了以初期投资最小为优化目标、满足系统无功需求的滤波器优化配置的数学模型。算例计算和仿真结果表明了上述优化模型及其滤波方式的正确性和有效性。展开更多
基金part funding for this work from the Clean Sky JTI – Systems for Green Operations ITDsupported by the National Natural Science Foundation of China (No. 50807002)+1 种基金the Aeronautical Science Foundation of China (No. 2008ZC51045)the Beijing Nova Program (No. 2008B13)
文摘This paper presents an auto-tuning method for a proportion plus integral（PI） controller for permanent magnet synchronous motor（PMSM） drives, which is supposed to be embedded in electro-mechanical actuator（EMA） control module in aircraft. The method, based on a relay feedback with variable delay time, explores different critical points of the system frequency response.The Nyquist points of the plant can then be derived from the delay time and filter time constant.The coefficients of the PI controller can then be obtained by calculation while shifting the Nyquist point to a specific position to obtain the required phase margin. The major advantage of the autotuning method is that it can provide a series of tuning results for different system bandwidths and damping ratios, corresponding to the specification for delay time and phase margin. Simulation and experimental results for the PMSM controller verify the performance of both the current loop and the speed loop auto-tuning.
文摘三维城市模型是智慧城市与数字孪生城市的核心内容。IFC(industry foundation classes)标准构建的建筑信息模型(building information model,BIM)为城市空间规划和建筑设计提供了丰富而精细的城市三维模型数据。由于标准的差异,BIM无法与三维地理信息系统无缝集成和交互应用,极大地限制了IFC标准BIM的应用优势。本文挖掘IFC、CityGML(city geography markup language)标准三维建筑模型的语义表达差异,提出BIM源模型向不同细节层次(level of detail,LOD)层级模型的几何转换方法;构建一套完整的转换流程,实现IFC标准BIM向CityGML标准三维建筑模型的几何转换;设计并开发转换原型系统。研究表明:本方法及实现流程能够有效实现IFC-BIM模型向CityGML-BIM模型的不同LOD层级的转换,且对多数单体模型相当实用;转换后模型未见错误与偏差,视觉效果良好;具备灵活性,可根据不同模型的转换进行调整。研究成果为BIM与地理信息系统的集成应用提供了新思路,为智慧城市与数字孪生开辟了一种新的数据来源通道。
文摘An overview of recent advances in digital control of low-to medium-power DC/DC switching converters is presented.Traditionally,analog electronics methods have dominated in controlling such DC/DC converters.However,with the steadily decreasing cost of ICs,the feasibility of digitally controlled DC/DC switching converters has increased sig-nificantly.This paper outlines a sample of digital solutions for DC/DC switching converters to enhance the performance of DC/DC switching converters.Furthermore,latest research activities pertaining to applications for steady-state and dy-namic performance improvement,such as efficiency optimization,controller auto tuning,and capacitor charge balance control,is discussed.These applications demonstrate the significant advantages and potentials of digital control.
文摘传统的高压直流输电(high voltage direct current,HVDC)系统一般在换流站交流网侧布置滤波兼无功补偿装置,谐波与无功功率通过换流变压器回馈网侧时会对变压器产生不良的影响。作者基于自耦补偿与谐波屏蔽的换流变压器,针对某实际的HVDC模拟系统,提出了与该变压器配套的滤波装置的接线方案,并将外罚函数法和遗传算法相结合,对上述滤波装置进行优化设计,建立了以初期投资最小为优化目标、满足系统无功需求的滤波器优化配置的数学模型。算例计算和仿真结果表明了上述优化模型及其滤波方式的正确性和有效性。
