【作者】 陈起；

【导师】 贾贵玺；

【作者基本信息】 天津大学 ， 电力电子与电力传动， 2007， 硕士

【摘要】 同步发电机励磁控制系统为发电机提供励磁,并将发电机端电压维持在给定水平,是同步发电机的重要组成部分。对于单台并网运行的小型同步发电机,由于受容量的限制,通过小机组励磁控制提高电压水平,进而改善系统的稳定性的作用有限,如果小机组在发出有功的同时,不承担一定的无功出力,必然造成所在的区域的无功缺额扩大,使区域电压水平严重下降。因此在确保小机组发出一定有功的同时,发出相应量的无功,即功率因数恒定更具有实际意义。基于励磁电流和功率因数的双闭环系统可以实现恒功率因数控制。本文针对以往双闭环系统存在的不足,在双闭环恒功率因数控制的基础上,设计了以DSP为核心控制器件的数字励磁调节器,采用自并励励磁方式,以IPM组成三相电压型PWM整流器,并网前调节励磁电流,使发电机空载电势符合并网条件。并网后投入功率因数环,以径向基(RBF)函数神经网络控制器调节功率因数,使功率因数准确、快速地跟随给定值。三相电压型PWM整流器与传统的二极管整流器和可控硅整流器相比,具有交流侧输入、输出电流谐波分量小、功率因数可调、直流侧电压波动小、能量可以双向流动等优点。径向基(RBF)函数神经网络很好地解决了励磁电流与功率因数之间非线性控制的难题。本文给出了Matlab仿真波形,系统的软硬件设计方案。更多还原

【Abstract】 The Excitation Control Systems of synchronous generators have an important effect on the stability of power systems; moreover, excitation regulators play the role of a nucleus in the excitation control systems. However,for the small synchronous generator connected to grid, it is unfeasible to improve the net voltage and the transient stability of generator by adjusting excitation system, so maintaining power factor invariable after it is connected to the grid is more practically. This article adopts excitation current and power factor double-loop control method, designs a kind of digital excitation controller based on TMS320F2812 DSP.Compared to traditional phase controlled rectifiers, PWM converter has the attractive features such as controllable power factor, nearly sinusoidal input current, simplicity in control circuit and bidirectional power flow ability. So,this article adopts PWM converter instead of traditional phase controlled rectifiers to completed high power factor rectify.Due to the nonlinear relation between excitation current and power factor, a sequential algorithm for radial basis function (RBF) networks referred to as the generalized growing and pruning algorithm for RBF (GGAP-RBF) is introduced and then uses it in the learning algorithm to realize parsimonious networks. The structure of this controller makes no need to use another neural network for on-line system identification and determining the structure of neural network controller in advance.In this paper, the design scheme of the whole Digital Excitation system using three- phase full control bridge rectifier is presented. All of the logic diagram of the hardware, the circuit schematic figures and the software’s flowcharts are also presented.更多还原