抑制电网无源补偿支路谐振的有源频变电阻控制策略研究

To prevent the resonance between passive LC filter and the grid effectively, a resistor can be installed, which can also consume lots of active power loss. The studies in the project will focus on the control strategy named active harmonic resistance based on high frequency power electronics converter. Using this control strategy the converter is controlled to display variable resistance properties to replace the resistor in passive branches, damping potential resonance, enhancing the power grid stability, and not influencing the passive branch to compensate reactive power and filter the harmonic waves. At the same time, apart from some switching loss, the converter can exchange different energy without consuming active power energy. Comparing to the existing methods of damping the resonance in hybrid power filters, the converter is always working as a resistor. It doesn't need to install additional CT/PT in high voltage terminal of the power supply and to get the accurate parameters of passive branch, which can simplify the application conditions..This project will firstly analyze the frequency characteristic of active harmonic resistance, and then discuss the methods which can control the energy exchange between fundamental frequency and non- fundamental frequency, through exploring the two ways which cooperate with different passive branches in different topologies, at last get a new control strategy as the passive branch impedance parameters change.

在各种无源LC补偿装置中设置电阻器，可以有效防止无源支路引起的谐振现象，但也会造成大量有功损耗。本项目研究一种基于高频电力电子变流器的有源频变电阻控制策略。采用这种控制策略，变流器对外表现为随频率变化的电阻特性，可以取代无源支路中的电阻器，在不影响无源支路补偿无功、滤除谐波功能的情况下，阻尼潜在谐振，增强电网稳定性。同时，除少量开关损耗外，变流器不会消耗有功能量，仅完成能量交换的功能。与现有混合滤波器抑制谐振的实现方式相比较，变流器始终处于阻性工作状态，不需要在供电网高压端增设CT/PT电量传感器，也不需要无源支路的精确参数，从而简化了应用条件。.本项目从有源谐波电阻频率特性的分析出发，研究变流器中非基波频率能量与基波频率能量之间实时转换的控制方式，探索配合不同拓扑结构无源支路时变流器的两类控制方法，进而获得无源支路阻抗变化情况下的控制策略。

配网中，无源补偿支路中的电阻器会产生大量有功损耗。本项目使用变流器替代该无源电阻器，从而达到减小损耗并改善无源补偿性能的目的。.本项目主要研究内容及结论如下：1）有源谐波电阻控制方式下，电力电子变流器在谐波频段上呈现电阻特性，吸收的谐波有功能量，转化为基波能量回馈电网。2）基于并联注入结构和串入式结构的有源谐波电阻可使用两种不同的控制方法，都可以实现阻尼谐振的目的。3）串入式结构的有源谐波电阻可以实现无功补偿电容器组无功补偿容量无法实现连续可调的功能。4）利用谐振模态分析法，将配电网系统复杂的节点电压关系、回路电流关系转换到模态关系中。利用模态关系描述配电网系统的优点是可以实现解耦分析，从而可以为合理的确定有源阻尼电阻的取值提供重要的参考。5）利用间谐波注入的方法可以在线辨识配电网阻抗参数，从而实现有源谐波电阻阻值的在线优化。.本项目的研究表明，有源谐波电阻的控制方法具有优异的推广价值。