基于定频PWM稳压的电流互感器取能电源设计方法

Design Method of Current Transformer Energy Extracting Power Supply Based on Constant Frequency PWM Voltage Stabilization

针对输电线路电流大范围波动导致在线取能装置能量溢出问题,利用脉冲宽度调制技术能够有效地对取能装置进行稳压。计及常规高频PWM信号所引起晶体管的死区问题,在常规PWM稳压的基础上提出了一种能够自适应稳压同时在电流巨大时不需要高频PWM波的取能装置。首先在分析电流互感器取能原理的基础上建立取能负载模型,推导出负载电压与电流互感器母线电流的关系,通过引入开关电路,由固定频率PWM脉冲信号控制晶体管的导通与关断,从而解决电流过大时能量溢出问题;同时构建仿真实验平台,仿真验证该方法能够在母线电流变换的条件下达到自动调节取能负载电压的效果,证明了所提方法的可行性。

In view of the large-scale current fluctuation of the current of the transmission line,causing the energy overflow of on-line energy acquisition device,pulse width modulation technology is applied to voltage stabilization control of the energy extracting device.Considering the dead zone of transistor caused by the conventional high-frequency PWM signal,on the basis of conventional PWM voltage stabilization,the paper proposes an energy extracting device capable of self-adaptive voltage stabilization without high-frequency PWM waves when the current is huge.Firstly,the energy extraction load model is established by analyzing the principle of current transformer energy extraction,and the relationship between the load voltage and the bus current of the current transformer is derived.By introducing a switch circuit,PWM pulse signal with a fixed-frequency is used to turn on and off the transistor,thereby solving the energy overflow when the current is too big.At the same time,a simulation experiment platform is built to verify that the method can achieve the effect of automatically adjusting the load voltage under the condition of bus current conversion,and has the feasibility.