【作者】 姜桂秀；

【导师】 王成山； 张炳达；

【作者基本信息】 天津大学 ， 电力系统及其自动化， 2010， 博士

【摘要】 为了很好地进行电力系统动态模拟试验，需要特别定制的负载。随着试验的复杂化，负载参数的调整和改变比较麻烦，准确度也不太高。电子负载的优点正好弥补了传统负载装置的不足。本文研究的交流电子负载既能够精确控制负载特性又能将试验能量反馈到电网。在对三种已有的交-交变换电路进行了分析比较的基础上，确定采用稳定性较好的中间直流环节AC/DC/AC结构作为电子负载的主电路拓扑结构和基于电压型PWM整流器的三相交流电子负载的整体框架。同时，简要分析了交流侧电感和直流电容选择的原则。采用双滞环空间矢量电流控制方法，以弥补滞环空间矢量电流控制时无法快速跟踪变化率较大的指令电流矢量的不足，实现三相VSR的电流跟踪控制、降低开关频率和抑制电流谐波。同时，研究了确定参考电压矢量方法，使得本周期指令电压矢量V refn的所在区域可以通过上周期的输出电压矢量V k，上周期的误差电流ΔI n1和本周期的误差电流ΔI n来确定。提出了基于BP算法的预测电流控制策略：在不提高控制器的采样频率的前提下，利用历史电流数据预测指令补偿电流，实现空间矢量滞环控制器的无差拍控制，以获得更好的电流跟踪效果。通过仿真计算，验证了双滞环空间矢量电流控制方法和基于BP算法的预测电流控制策略的有效性。在电能回馈单元，采用了电流内环和电压外环的双闭环控制作为控制策略，并将模糊控制技术与传统的PI控制方法相结合，组成了适合电压外环的模糊PI控制器。为简化模糊推理过程和提高控制器的控制速度，推导出了适合查询的模糊控制策略表。仿真结果证明使用模糊PI控制器的控制策略，能够得到更快的响应速度和更小的超调。讨论了异步电动机的物理模拟方法，异步电动机的等效模型，及其所带各种机械负载的特性。通过对设计的异步电动机电子负载在起动、稳态、电源扰动以及负载扰动的测试，证明了设计的正确性。同时，为实际应用异步电动机电子负载提出了一些建议。更多还原

【Abstract】 In dynamic physical simulation of power system, the special custom load isneeded for the trouble-free operation. With the experiment being more complex, theparameter adjustment and modification of load become more difficult, and theaccuracy is decreased. Electronic load can just make up the shortage of classical loaddevice. The AC electronic load studied in this paper can both control the loadcharacteristic precisely and feedback the test engry to the grid.Based on the analysis of three existing kinds of AC-AC converter, theintermediate DC link that has better stability is choosen to be the electronic load maincircuit topology. The framework of three-phase AC electronic load that based on thebasic principles of PWM voltage rectifier is set up. And the select principle of AC sideinductance and DC side capacitor is briefly analysised.The current control method based on double hysteredsis current control and spacevector is taken, so the drawback that the current vector which has bigger change ratecannot be traced quickly can be made up. The current tracing control of three phaseVSR can realized, the switching frequency can be decreased, and the harmonizationcan be suppressed. The approach for determining the reference voltage vector isstudied, and the area of the reference voltage vector of this period can be determinedthrought out the output voltage vector of last period, the error current vector of lastperiod, and the the error current vector of this period.The predicting current control based on BP algorithm is presented. When thesampling frequency isn’t very high, the reference offset current of next time ispredicted using of historical current. So that, the no beating control of SVPWM basedon hysteredsis is realized, and the better tracing is got. The double hysteredsisSVPWM current control and the predicting current control based on BP algorithm areproved to be correct through the test.Double closed loop combined with voltage outer loop and current inner loop isused as control strategy for feeding back engry. The Fuzzy PI controller using involtage outer loop is consisted of fuzzy control technique and traditional PI controlmethod. In order to simplify the Fuzzy inference process and increase the controlspeed, the fuzzy control strategy table is obtained. The anticipation that controlstrategy with fuzzy PI controller can achieve a quicker response speed and a smaller overshoot is proved in the simulation results.The physical simulation method for asynchronous motor and its load, theequivalent model of asynchronous motor and types, and characteristics of all kinds ofmechanical load are discussed. The simulation results of asynchronous motordrugging different kinds of load are obtained in the events that in starting, in steadystate, with disturbances on power supply side and load side. The design withelectronic load in the field of circuit control is proved to be correct and feasible. Someadvices are proposed for the practical application of asynchronous motor electric load.更多还原