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基于单相谐波电流源模型的无功补偿装置过电压判据 被引量:1
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作者 刘智谦 杨典语 王晓丹 《智能电网》 2016年第9期901-907,共7页
针对目前规避电网谐波危害而采用的滤波方法的不足,在建立民用建筑低压侧等效电路模型并分析参数与补偿电容容量及变压器规格等发生并联谐振时的关系,剖析系统并联谐振机制的前提下,结合并联电容器长期运行电压极限值,构建系统无功补偿... 针对目前规避电网谐波危害而采用的滤波方法的不足,在建立民用建筑低压侧等效电路模型并分析参数与补偿电容容量及变压器规格等发生并联谐振时的关系,剖析系统并联谐振机制的前提下,结合并联电容器长期运行电压极限值,构建系统无功补偿过电压判据,优化并联电容器组投切策略。针对某一民用建筑物的低压(0.4 kV)配电系统,基于实际测量的母线电压U_L、负荷侧电流i_L与无功补偿并联电容器组电流i_c,分析其电流电压谐波特性;利用系统无功补偿过电压判据进行过电压规避,并进行仿真验证,以此形成一套可推广到其他民用建筑的规避过电压的方法。 展开更多
关键词 单相谐波电流模型 并联谐振 过电压判据 电容器组投切
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城市路况下电动汽车驱动器最优开关频率选择探讨
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作者 杨中哲 王恩隆 杨欢 《微电机》 北大核心 2020年第10期32-37,共6页
新能源汽车在城市路况上低速行驶时,由于此时电机输出功率较低,电机驱动器将会运行在低调制比工况下,此时脉冲宽度调制(PWM)带来的谐波会与非理想开关过程带来的谐波对电机工作效率与性能的影响会增加。为了在这种工况下获得良好的电机... 新能源汽车在城市路况上低速行驶时,由于此时电机输出功率较低,电机驱动器将会运行在低调制比工况下,此时脉冲宽度调制(PWM)带来的谐波会与非理想开关过程带来的谐波对电机工作效率与性能的影响会增加。为了在这种工况下获得良好的电机性能,需要选择合适的电机驱动器开关频率最大程度的降低两种谐波的影响。通过综合考虑两种谐波的表达式,提出了一种开关频率的优化选择方案,并在Matlab中对方案进行了计算和仿真验证。 展开更多
关键词 电动汽车 永磁电机驱动器 最优开关频率选择 电流谐波模型
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Prediction of Core Losses of Three-Phase Distribution Transformer
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作者 Mihail Digalovski Krste Najdenkoski Goran Rafajlovski 《Journal of Energy and Power Engineering》 2013年第12期2347-2353,共7页
Transformers are normally designed and built for use at rated frequency and sinusoidal load current. A non-linear load on a transformer leads to harmonic power losses which cause increased operational costs and additi... Transformers are normally designed and built for use at rated frequency and sinusoidal load current. A non-linear load on a transformer leads to harmonic power losses which cause increased operational costs and additional heating in transformer parts. It leads to higher losses, early fatigue of insulation, premature failure and reduction of the useful life of the transformer. To prevent these problems, the rated capacity of transformer which supplies harmonic loads must be reduced. In this work, a typical 50 kVA three-phase distribution transformer with real practical parameters is taken under non-linear loads generated due to domestic loads. The core losses is evaluated using the three dimensional model of the transformer developed in FEM (finite element method) program based on valid model of transformer under high harmonic conditions. And finally a relation associated with core losses and amplitude of high harmonic order are reviewed & analyzed and then a comparison is being carried out on the results obtained by different excitation current in transformer windings. 展开更多
关键词 Core losses three-phase transformer HARMONIC 3D model finite element method magnetic flux distribution.
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