【作者】 张楠；

【导师】 章玮；

【作者基本信息】 浙江大学 ， 电机与电器， 2013， 硕士

【摘要】 电力测功机是一种新型的测功机,能够将测功产生的能量返回到电网或与其他电动装置形成能量循环,一方面可以实现节能,另一方面很大程度的提升了测功机系统的动态性能和稳定性,是传统测功机的理想替代品。本论文在分析了不同种类电力测功机特点的基础上,提出了基于矢量控制技术的两种交流电力测功机方案,分别为独立式能量回馈型电力测功机系统方案和电封闭式电力测功机系统方案,这两种方案中使用具有结构简单、运行可靠等优点的鼠笼式异步电机作为测功电机。方案中均能够将测试中所产生的能量进行回收利用,或者回馈到三相电网,或者返回到直流母线供被测电机使用,达到高效、节能的目的,具有很高的工程应用价值。两种电力测功机方案中均采用“交—直—交”结构作为主电路。独立式方案中为了实现能量双向流、回馈电能的高功率因数,采用了三相PWM整流控制技术作为前级“交—直”转换控制；对后级的“直—交”转换控制采用基于转子磁场定向的矢量控制技术来实现；电封闭式方案中采用共直流母线结构,通过使用基于矢量控制的双机侧模型来控制测功电机和被测电机,实现能量的循环利用。仿真和实验结果验证了这两种方案的可行性。通过对异步电机传统矢量控制方法的分析和研究,针对坐标变换后产生的交叉耦合电势,所引起的电流内环的动态响应能力下降,从而使得转矩、功率外环的控制性能下降的缺点,本文中通过分析交叉耦合电势,将前馈解耦补偿引入电流内环,并将耦合项的计算直接使用系统外环的给定值来获得,进一步提高补偿项的快速性,从而改善电流内环的动态响应能力。同时针对矢量控制的双环结构,本文使用模糊自适应PI调节器来代替系统外环的传统的PI调节器,同时简化了模糊规则表,使之易于数字实现,并通过寻找系统动态响应的最优语义轨迹,来修正模糊规则表和隶属度函数,从而获得最快的转矩、功率响应速度,有效的提高系统的动态性能。由于电封闭式电力测功机系统中存的共直流母线结构,而突加、突减负载时均会引起母线电压较大的波动,降低了直流母线电压的稳定性,本文研究了直流母线电压波动对逆变器输出和电机性能的影响,并提出了改进的VVVF控制方法,提高了系统的抗扰动能力,保证运行的稳定性。通过仿真和实验证明,本文所研究、提出的两种交流电力测功机方案,均具有良好的稳态性能和动态性能,且节能效果优良,具有很好的推广应用价值。更多还原

【Abstract】 Power Dynamometer is a new type dynamometer, which is able to transfer the power back to the grid or other electric devices to form energy cycle. On one hand, it can achieve energy, on the other hand, the dynamic performance and stability of the dynamometer system has improved significantly. Based on analyzing of the basic principles and characteristics of the different type of power dynamometers, this thesis proposed two AC power dynamometer program based on vector control technology, which were stand-alone energy feedback power dynamometer system and closed power dynamometer system. Both programs use squirrel-cage three-phase induction motor as dynamometer motor because of the advantages of simple structure, reliable operation. The two programs can achieve efficient, energy-saving purposes, which have a large engineering practical value.The main circuit of the two dynamometer programs is AC-DC-AC configuration. In stand-alone energy feedback power dynamometer system, in order to realize bi-directional power flow and better dynamic and static performance, it adopts three-phase PWM technology for AC-DC conversion control and vector control technology of induction motor for DC-AC conversion control. In closed power dynamometer system, the double machine side model is used to achieve energy cyclesutilization. The simulation and experimental results verify the feasibility of the two programs.Through the analysis and research of the traditional vector control method used in induction motor, in order to decrease the influence of the cross-coupling voltages after coordinate transformation which could decrease the dynamic response capability of system, a new feedforward decoupling compensation method is introduced to the inner cuurent loop. At the same time, when calculating coupling items, the given values such as power or torque of the outer loop are directly introduced in to improve the currents dynamic response better. Also the fuzzy adaptive PI regulator is used to instead of the traditional PI regulator in outer loop of the system to improve the dynamic response of power and torque which influence the dynamometer performance directly. In order to obtain the fastest speed of torque and power response, this thesis simplified the fuzzy rules to make it easier to digital implementation and fixed the fuzzy rules and membership functiuns by finding the optimal semantics trajectory. This method effectively improve the dynamic performance of the system.In closed power dynamometer system, sudden applied or reduction load will cause a large DC-bus voltage fluctuations making the DC bus voltage less stable becacuse of the common-DC bus structure. This paper studies the impact of the inverter output and motor performance caused by the DC-bus voltage fluctuations, and proposed an improved VVVF control method to improve anti-disturbance ability of the system and ensure the stable operation of the power dynamometer system.Through the research and experimental results, it can be verified that the key technologies for stand-alone energy feedback power dynamometer system and closed power dynamometer system have good steady-state performance, dynamic performance, excellent energy saving effect, and have a good application value.更多还原