随着高压直流输电工程的不断投产,以及风电项目的增多,越来越多的风电场出现在电网换相换流器高压直流输电(line-commutated-converter based high voltage direct current,LCC-HVDC)受端换流站近区,两者构成的系统存在振荡风险。为此,...随着高压直流输电工程的不断投产,以及风电项目的增多,越来越多的风电场出现在电网换相换流器高压直流输电(line-commutated-converter based high voltage direct current,LCC-HVDC)受端换流站近区,两者构成的系统存在振荡风险。为此,该文针对直流受端馈入站与近区风电场系统的振荡特性展开研究。首先,建立并验证系统的状态空间模型,基于该模型计算出系统特征值,确定LCC-HVDC与风电场共同参与的振荡主导模式并进行参与因子分析。进一步地,通过对比是否接入LCC-HVDC的主导模式,得到LCC-HVDC的接入会削弱系统阻尼的结论。最后,从系统额定容量、交流系统短路比、风电场并网线路长度等方面探究系统稳定性的影响因素,并分析系统的不同短路比、潮流比对风机网侧换流器(grid-side converter,GSC)外环控制和换流站定电流控制器性能的影响。展开更多
This paper proposes a design and implementation of the bi-directional DC-DC converter for Wind Energy Conversion System. The proposed project consists of boost DC/DC converter, bi-directional DC/DC converter (BDC), pe...This paper proposes a design and implementation of the bi-directional DC-DC converter for Wind Energy Conversion System. The proposed project consists of boost DC/DC converter, bi-directional DC/DC converter (BDC), permanent magnet DC generator and batteries. A DC-DC boost converter is interface with proposed wind system to step up the initial generator voltage and maintain constant output voltage. The fluctuation nature of wind makes them unsuitable for standalone operation. To overcome the drawbacks an energy storage device is used in the proposed system to compensate the fluctuations and to maintain a smooth and continuous power flow in all operating modes to load. Bi-directional DC-DC converter (BDC) is capable of transforming energy between two DC buses. It can operate as a boost converter which supplies energy to the load when the wind generator output power is greater than the required load power. It also operates in buck mode which charges from DC bus when output power is less than the required load power. The proposed converter reduces the component losses and increases the performance of the overall system. The complete system is implemented in MATLAB/SIMULINK and verified with hardware.展开更多
为准确计算励磁电流,采用有限元法分析了交错磁极(consequent-pole permanent magnet,CPPM)无刷直流发电机(brushless DC generator,BLDCG)电励磁磁场和永磁磁场的耦合特点,讨论了电枢电流换流过程及其对励磁电流的影响,在此基础上推导...为准确计算励磁电流,采用有限元法分析了交错磁极(consequent-pole permanent magnet,CPPM)无刷直流发电机(brushless DC generator,BLDCG)电励磁磁场和永磁磁场的耦合特点,讨论了电枢电流换流过程及其对励磁电流的影响,在此基础上推导出考虑磁场耦合和换流过程的励磁电流表达式.实验结果表明:计及磁场耦合和电枢电流换流过程可以提高励磁电流计算的准确度.展开更多
文摘随着高压直流输电工程的不断投产,以及风电项目的增多,越来越多的风电场出现在电网换相换流器高压直流输电(line-commutated-converter based high voltage direct current,LCC-HVDC)受端换流站近区,两者构成的系统存在振荡风险。为此,该文针对直流受端馈入站与近区风电场系统的振荡特性展开研究。首先,建立并验证系统的状态空间模型,基于该模型计算出系统特征值,确定LCC-HVDC与风电场共同参与的振荡主导模式并进行参与因子分析。进一步地,通过对比是否接入LCC-HVDC的主导模式,得到LCC-HVDC的接入会削弱系统阻尼的结论。最后,从系统额定容量、交流系统短路比、风电场并网线路长度等方面探究系统稳定性的影响因素,并分析系统的不同短路比、潮流比对风机网侧换流器(grid-side converter,GSC)外环控制和换流站定电流控制器性能的影响。
文摘This paper proposes a design and implementation of the bi-directional DC-DC converter for Wind Energy Conversion System. The proposed project consists of boost DC/DC converter, bi-directional DC/DC converter (BDC), permanent magnet DC generator and batteries. A DC-DC boost converter is interface with proposed wind system to step up the initial generator voltage and maintain constant output voltage. The fluctuation nature of wind makes them unsuitable for standalone operation. To overcome the drawbacks an energy storage device is used in the proposed system to compensate the fluctuations and to maintain a smooth and continuous power flow in all operating modes to load. Bi-directional DC-DC converter (BDC) is capable of transforming energy between two DC buses. It can operate as a boost converter which supplies energy to the load when the wind generator output power is greater than the required load power. It also operates in buck mode which charges from DC bus when output power is less than the required load power. The proposed converter reduces the component losses and increases the performance of the overall system. The complete system is implemented in MATLAB/SIMULINK and verified with hardware.
文摘为准确计算励磁电流,采用有限元法分析了交错磁极(consequent-pole permanent magnet,CPPM)无刷直流发电机(brushless DC generator,BLDCG)电励磁磁场和永磁磁场的耦合特点,讨论了电枢电流换流过程及其对励磁电流的影响,在此基础上推导出考虑磁场耦合和换流过程的励磁电流表达式.实验结果表明:计及磁场耦合和电枢电流换流过程可以提高励磁电流计算的准确度.