可变频变压器的建模仿真与分析

摘要

采用高压直流输电方式连接两个异步电网存在谐波干扰、换相失败、难以实现功率平滑调节、无功功率不能随有功功率传输等问题.文章介绍了可变频变压器的的基本结构及原理,研究了可变频变压器的数学模型及控制模型,给出了可变频变压器传输功率与直流驱动电动机提供的驱动转矩之间的数学关系式,在此基础上采用PSCAD软件搭建了可变频变压器模型并进行了仿真研究.仿真结果表明,可变频变压器可以实现两个异步电网之间的连接并进行功率双向平滑传输,响应速度快;通过转速控制器控制直流驱动电动机的转速可使旋转变压器的转速恒定,以弥补两个电网的频差,维持系统平衡.%Connecting two asynchronous power networks by use of high voltage DC method has problems of harmonic interference, commutation failure, difficult implement of smooth power regulation and so on at present. The paper introduced basic structure and principle of variable frequency transformer, researched mathematic model and control model of the variable frequency transformer, and gave mathematic formula of transmission power of the variable frequency transformer and driving torque generated by DC driving motor. Then it built simulation model of the variable frequency transformer by use of PSCAD software and did simulation research. The simulation result showed that the variable frequency transformer can connect two asynchronous power networks and realize smooth bidirectional power transmission with quick response. Meanwhile, controlling speed of DC driving motor by control speed controller can make speed of rotate transformer constant, so as to compensate frequency difference of the two power networks and keep system balanced.