三相连续型阻塞式交-交变频调速系统研究

AC-AC variable frequency regulating system based on three-phase continuous plugged pulse principle

针对以晶闸管作为功率器件的传统交-交变频调速系统具有功率器件较多和成本较高等特点,通过对传统交-交变频调速系统和脉冲阻塞原理的分析,采用恒压频比的控制策略进行了三相连续型脉冲阻塞式交-交变频调速系统的研究。依据面积等效原理,对阻塞后的输出电压进行了变脉宽斩波控制方式的详细理论分析,推导出了变脉宽斩波控制中相应输出电压幅值的数学表达式,为输出电压幅值的控制提供依据。设计了三相连续型阻塞式交-交变频调速系统,实现了输出电压和频率的同时可调。在Matlab/Simulink环境下建立系统仿真模型,进行仿真试验,验证了该方法的正确性,且该法具有控制简单、输出电压正弦度较好、功率器件较少、带载能力强、体积小等优点,适合电动机中低速下的调速运行,具有一定的实际应用价值。

The traditional AC/AC variable frequency speed regulation system using thyristor as power device is characterized by many power devices and higher cost.Based on the analysis of traditional AC/AC frequency conversion speed regulation system and plugged pulse principle,a variable frequency regulating system on the base of three-phase continuous plugged pulse principle was studied by adopting constant voltage frequency ratio control strategy.According to the area equivalent rule,the control mode of variable pulse width chopping for the output voltage after plugged was analyzed in detail,and the algorithmic expression of output voltage amplitude in the variable pulse width chopping control was deduced,which provide the basis for the control of the output voltage amplitude.The variable frequency regulating system based on three-phase continuous plugged pulse principle was designed,and the output voltage and frequency could be adjusted simultaneously.The system simulation model was established under the environment of Matlab/Simulink,and the simulation experiment was carried out.The results showed that the proposed method was correct and had such advantages as simple control,better sinusoidal output voltage,less power devices,strong carrying capacity,and small size.It was suitable for low speed operation of the motor,and had certain practical application value.