Subjects: Dynamic and Electric Engineering >> Electrical Engineering submitted time 2019-03-05 Cooperative journals: 《电气工程学报》
Abstract:固态变压器作为能源互联网的核心设备具有电压等级转换和隔离的功能, 可以有效地整合分布式可再生能源,但模块级联 H 桥型固态变压器也存在各个 H 桥模 块之间的均压问题。本文首先研究了单相任意单元数级联 H 桥固态变压器的 SVPWM 及其电压平衡控制原理,提出一种固态变压器电压环控制一个 H 桥直流母线电压,然 后通过在 SVPWM 中增加一个新控制环控制其他 H 桥的矢量脉冲宽度,从而使其他 H 桥电压跟随的控制策略来实现各个 H 桥均压的目的。最后通过仿真验证了所提控制策 略的正确性。
Subjects: Dynamic and Electric Engineering >> Electrical Engineering submitted time 2019-03-05 Cooperative journals: 《电气工程学报》
Abstract:提出了一种应用于高压场合的三相线电压级联型高频链矩阵整流器(LVCHLFMR)拓扑,该拓扑由基于 HLFMR 单元模块的三相线电压级联型变换器、高频变 压器、单相整流器构成,可直接与三相系统相连,具有开关数量少、省略直流储能环 节及结构紧凑等优点。分析了 HLFMR 的调制策略,在此基础上提出了针对三相桥直 接级联结构特点的 HFLMR 改进换流策略,解决了采用常规换流时出现的负载开路问 题,以及变换器工作状态切换至零矢量时的瞬时相间短路问题,仿真结果表明所提拓 扑的正确性及改进换流策略的有效性。
Subjects: Dynamic and Electric Engineering >> Electrical Engineering submitted time 2019-03-05 Cooperative journals: 《电气工程学报》
Abstract:同步逆变器通过模拟同步电机内部机理和外部特性使其对电网具有天然友 好的特性,但其有功功率和无功功率之间存在的耦合会加剧同步频率谐振,容易引发 功率振荡,导致系统不稳定。本文首先建立同步逆变器功角特性的小信号模型,分析 产生功率耦合的机理。在此基础上,针对功率耦合问题提出了一种新型的功率解耦控 制方法:通过添加反馈电流环对耦合功率进行动态补偿,将引起耦合的动态功率量转 换成动态电流的形式,消除了由功率耦合引起的动态功率振荡和虚拟同步控制的稳态 误差,并对加入反馈电流环的控制系统进行了稳定性分析,最后通过仿真验证了该方 法的有效性和可行性。
Subjects: Dynamic and Electric Engineering >> Electrical Engineering submitted time 2019-03-05 Cooperative journals: 《电气工程学报》
Abstract:永磁同步电机与其他类型电机相比性能指标尤为突出,被广泛应用于各个 领域。随着电机制造业的发展,电机单机容量增加,使电机内部温升过高,影响电机 的性能与可靠运行。本文在考虑高速电机永磁体涡流损耗对电机温度场的影响的情况 下,用集总参数热网络法(LPTN)对永磁同步电机进行温度场分析,建立 38 节点的 热网络模型,真实反映了电机各部件的温升。最后,通过与有限元法(FEM)分析结 果、电机温升试验结果对比,证明该热网络计算模型的正确性。
Subjects: Mechanical Engineering >> Other Disciplines of Mechanical Engineering submitted time 2018-06-15 Cooperative journals: 《电气工程学报》
Abstract: Solid-state transformer has the function of conversion and isolation in different voltage grade as the important equipment of energy internet, and it can integrate distributed renewable energy effectively, but also has some imbalance problem in voltage. At first,the SVPWM of single-phase solid-state transformer cascaded by arbitrary number of H bridge and the principle of voltage balance control are studied in the paper. Then, a control strategy which control one of H bridge's voltage through solid-state transformer voltage control loop is proposed, and this strategy control other H bridge's voltage to follow master H bridge by adding a new control loop in the SVPWM which control the vector pulse width of each slave H bridge. Finally, the simulation verifies the correctness of strategy proposed.
Subjects: Mechanical Engineering >> Other Disciplines of Mechanical Engineering submitted time 2018-06-15 Cooperative journals: 《电气工程学报》
Abstract: An three-phase line-voltage-cascaded high-frequency link matrix rectifier (LVC-HLFMR) topology applied in high-voltage situations is proposed in the paper. The topology consists of three-phase line voltage cascaded converter which based on HLFMR unit module, high frequency link transformer, single-phase rectifier,and it can be directly connected to a three-phase system. It has the advantages of few switch quantity, omit the dc energy storage link, compact structure, etc. The HLFMR modulation strategy is analyzed, on this basis an improved commutation strategy is proposed according to the three-phase bridge direct cascade structure characteristics. The problem of open load when using the conventional commutation strategy and the instantaneous short circuit problem when converter work status switch to zero vector are solved. The simulation and experimental results verify the validity of the proposed topology and the effectiveness of the improvement commutation strategy.