【作者】 郑伟锋；

【导师】 何湘宁； 马皓；

【作者基本信息】 浙江大学 ， 电气工程， 2013， 博士

【摘要】 近年来,伴随世界性的能源危机,作为新能源技术中关键环节的逆变器及其并联系统控制成为学界热点。从另一方面来讲,网络化是工业技术革命的重要方向。将网络引入逆变器及其并联系统,首先可以利用网络信道将大量离线或在线数据上传至上位计算机处理,以判断运行状况、系统性能,或是直接给出运行控制信号。上位机强大的计算功能是一般单片机无法比拟的。高性能的计算能力允许高性能的控制算法的实施,其结果必然是高性能的运行效果。其次,逆变器之间的信息交互一直是学界讨论的重点问题。利用高速实时网络交互逆变器间信息,能够获得传统模拟线路和低速现场总线所不能比拟的优越性能。本文基于网络控制思想,所做的工作包括以下几个方面：1.提出了构建基于Ethercat网络协议的逆变器网络控制平台和基于网络控制的逆变器并联系统的方法。这种并联系统可以实现复杂的网络拓扑,实现高速实时的数据传输。在介绍了同步时钟的运行原理之后,从自动控制理论出发,基于D分割法,本文给出了确定比例积分控制的逆变器控制参数选取范围的方法。2.提出了通过网络辨识的方式获取逆变器参数,进而实现了网络控制逆变器基于反向模型的重复控制方法。文中使用最小二乘法,以频率成分丰富的M序列作为输入量,根据系统输入输出数据组实现系统参数的有效辨识。文中探讨了反向模型的构造方法,将基于反向阻尼模型的重复控制和传统重复控制方法做一比较,说明了一定元件参数和对比条件下基于反向阻尼模型的重复控制方法较之传统重复控制方法而言系统性能更佳。3.提出了网络控制下基于重复控制的逆变器瞬时均流方法。文中详细探讨了两种改进的重复控制器下并联系统均流控制器的稳定条件和参数范围,进而在理论上说明了基本重复控制器下的均流性能不及改进的重复控制方法下均流性能的客观原因。对于两种改进的重复控制器,文中做了比较,指出两者在动态性能上的差异。从系统稳定性出发,根据开关管及负载特性,文中详述了两种控制方法下控制参数的选择方法。从理论和实验两方面证明这种方法下系统带非线性负载时能获得优异的输出性能。4.提出了网络控制下基于反向阻尼模型的比例多谐振控制器控制逆变器及逆变器并联系统的实现方法。文中详述了这种方法控制下系统的稳定性、抗干扰性、稳态性能等一系列性能表现,以及网络延迟对控制器参数选取的影响。文中比较了多种离散化方法下数字谐振控制器的效果,数学上证明了这几种离散化方法在基于带反向阻尼模型的比例多谐振控制器的逆变器系统中的适用性。在分析单逆变器控制器之后,文中提出了逆变器并联系统均流环控制器的结构和参数选取方法,在电感电容参数一定幅度变化的测试下,验证了均流环控制器的鲁棒性。更多还原

【Abstract】 In recent years, energy crisis attracts great attention worldwide. The control of inverter, along with inverter parallel system, which plays an important role in the development of new energy technology, receives more attention from experts. Meanwhile, networked control is the future trend of technological revolution. The introduction of networked control into inverter and inverter parallel system would bring about several advantages. First, data produced either online or offline could be transferred to upper computer, which with its high calculation ability, would make correct judgment regarding system operation condition, system performance, or send control signal to local controller directly. The satisfactory computing capability of upper computer allows advanced control method with huge amount of data, leading to high quality operation performance. Compared to the traditional analogue circuit or low speed field bus, the high speed, real time network facilitates information exchange between inverters in a parallel system efficiently and speedily, which is a target electrical engineers have been striving for. With the concept of networked control, the main contribution of this dissertation is as follows.Firstly, based on Ethercat protocol, methodology for establishing a network controlled inverter and its parallel system is proposed. This parallel system allows complicated network topology. After the introduction of principles of distributed clock, the parameter range for a stable control system with a proportional-integeral controller is determined by D partition method.Secondly, by the way of networked identification, an inverse model based repetitive controller for inverter is proposed. In this method, the least-square-method is employed, along with M sequence as the input data. By processing input data and output data, parameters for inverter model are obtained. Next, the inverse model is modified in advance of being used as a compensator in the repetitive controller. Compared to results from traditional method, in certain conditions, a better control performance based on inverse damping model under nonlinear load is shown.Thirdly, in order to improve voltage performance under nonlinear load, in the context of networked control, an inverter parallel system based on repetitive control method is proposed. In this way, method to obtain stable control parameters of current sharing controller with two modified repetitive controller is discussed in detail. It is stated in theory that the performance of current sharing controller with traditional repetitive method is poorer than that of two modified repetitive controller. After theoretical analysis and experimental results, the difference of dynamic performance of two modified repetitive controller is discussed. According to automatic control theory, the parameter selection method of those modified repetitive controller is provided with the consideration of switch characteristic and load condition.Fourthly, a proportional plus multi-resonant controller with inverse damping model is proposed for inverter parallel system to achieve satisfactory steady-state and dynamic performance of output voltage. The system stability, anti-interference ability and steady-state performance are investigated in detail. Methods for converting continuous model to discrete model for a resonant controller is discussed, which shows several conversion methods are not suitable for a resonant controller, since the magnitude of resonant frequency would decrease by those conversion methods. After the discussion of single inverter design, design procedure of the current sharing controller for a parallel system is shown in detail. Also, the robustness of current sharing controller is proven by theoretical analysis when the value of inductor and capacitor-is changed within a certain range.更多还原