基于电流矢量的矩阵变换器—直接转矩控制系统研究

【作者】 郑剑武；

【导师】 喻寿益；

【作者基本信息】 中南大学 ， 电力电子与电力传动， 2010， 硕士

【摘要】 矩阵变换器能产生幅值、相位、频率均可调的输出电压,并且依靠其独特的双向开关能实现能量双向流通。将性能优良的矩阵变换器应用于异步电机直接转矩控制系统,组成矩阵变换器电机系统。矩阵变换器输入端电流性能差是矩阵变换器电机系统一个显著的缺点。为了改善矩阵变换器电机系统输入端电流特性,提出了一种简单有效的控制策略。首先分析异步电机的数学模型和直接转矩控制系统结构,阐述矩阵变换器工作原理及其控制策略；然后着重分析电压空间矢量脉宽调制(SVPWM)的工作原理和过程,对其工作效果和选择策略进行详细分析和说明,并将电压空间矢量分为高、中、低三个等级。为了提高电压使用率,仅选用高和中电压矢量作为控制信号实现SVPWM。为了改善矩阵变换器输入端电流品质,引入电流矢量对其进行正弦化控制,提出电压电流矢量协调控制策略,以使得在保持直接转矩控制性能的同时,能得到高性能的输入端电流。通过大量仿真实验,验证了此控制策略的有效性和矩阵变换器—异步电机系统的优越性能,既能保持矩阵变换器的理想特性,又兼有直接转矩控制的良好动静态性能,而且改善了输入端电流波形的正弦度。另一方面,在不改变电压电流矢量协调控制策略的基础上,仅通过增加一个电压矢量选择控制表就实现了电机制动和能量反馈。将异步电机减速运转过程中的大部分机械能回馈流向电网,并且实现异步电机快速停车,这对节约能源具有重大意义。更多还原

【Abstract】 Matrix converter can produce an output voltage with adjustable amplitude, phase and frequency, and the bidirectional switches can make the power flow in two ways.The excellent matrix converter is applied in direct torque control (DTC) system of asynchronous motor. It is called matrix converter-DTC bombined system. The input current of this system is with poor quality. An easy and effective control strage is proposed to improve the input current of this systemThe mathematical model of the induction motor and the structure of DTC system are analyzed, the work principle and control strategies of matrix converter are introduced, and the working processes of the voltage space vector are analyzed in detail.The voltage vector is divided into high, middle and low level according to the amplitude. To improve the voltage usage, high and middle levels are selected as control signal to realize SVPWM.Current vector control was introduced to improve the quality of input current of matrix converter. The control strategy that coordinate voltage vector with current vector can keep the performance of DTC and maintain the input current performance.The availability and superior performance of the system are verified through emulation in platform of MATLAB/Simulink. Both ideal characteristics of matrix converter and the good dynamic and static performance of DTC are retained, and the input current waveform is improved.Besides, a new vector control list is added to realize the brake and motor energy feedback. The mechanical energy of synchronous motor can be reverse circulate to the grid, and stop asynchronous motor quickly, which is of great significance to save energy.更多还原