三相PWM整流器仿真分析.doc

兰州交通大学毕业设计（论文） PAGE  PAGE - 51 - 三相电压型PWM整流器的数学模型和主电路设计 摘 要 传统的整流器一般采用二极管整流或相控整流，这种类型的整流器存在着输入电流非正弦，动态性能受到限制和功率因数较低的缺点。针对以上的问题，本文首先对三相电压型PWM（Pulse Width Modulation）整流器的工作原理进行了分析并得到系统的数学模型，然后推导出PWM整流器双闭环控制系统的传递函数框图并计算电流调节器和电压调节器的参数，最后通过MATLAB对三相电压型PWM整流器系统进行了仿真。本文采用开关函数法构建了三相VSR（Voltage Source Rectifier）的Simulink模型，它是依照变换电路的输入与输出的传递函数建立其模型，与电路的拓扑结构无关。文中详细地论述了电压和电流控制器、整流器、PWM发生单元等各子系统的Simulink建模，并基于所提出的模型研究了PWM整流系统开环控制和双闭环控制下的运行情况和系统特性。经过仿真发现仿真结果与理论分析相符，验证了模型的正确性。通过仿真发现滤波电感和直流侧电容参数对系统的稳态运行至关重要。从仿真的角度验证了三相PWM整流器比传统的相控整流器具备更加良好的性能。 关键词：三相电压型PWM整流器，数学模型，开环控制，双闭环控制 MATHEMATICAL MODEL AND MAIN CIRCUIT DESIGN OF THREE-PHASE VOLTAGE-SOURCE PWM RECTIFIER ABSTRACT The traditional rectifier, diode-bridge rectifier or phase-controlled rectifier, cause input current isnt sinusoidal waveform, low power factor, and dynamic performance is limited. In order to solve these problems, first, the mathematical model of 3-phase PWM VSR was created, second, the block diagram of double closed-loop controlled system for three-phase VSR was established. At the same time, the parameters of current regulator and voltage regulator can be calculated, finally, 3-phase PWM VSR was simulated by MATLAB. Based on the above studies, the simulink based model of 3-phase PWM VSR is obtained by using switching function concept which able to model converter circuits according to its input and output transfer functions. The simulink models of the voltage oriented control, voltage controller, current controller, rectifier and PWM generator are developed in detail, and based on these models can analyze the characteristics and system operation of open-loop control and double closed-loop controlled system. The simulation results verify the rectifying state validity of the proposed method. At last, through circuit simulation, we can find filter inductor and DC side capacitance is very important for system. Finally, we can find the PWM rectifier better than traditional rectifier. Key words: three-phase v