同相牵引供电系统中无锁相环的电流检测方法研究

为了实时准确的补偿同相铁路负载侧的基波无功电流与谐波电流,使三相电源侧的功率因数为1,从而达到三相平衡。传统的方法是利用三角函数正交特性,用加法器,乘法器,积分器,锁相环来实现基波有功电流与无功电流的检测。虽能避免大量的矩阵与反矩阵的运算,使整个电路成本变低,易于实现,但由于单相锁相环特有的相位延时,使得在锁定电压会产生初期的相位偏差,加上低通滤波器固有的延时,严重影响了电流检测的动态性能。基于上述问题,考虑到均值滤波器特有的快速响应性能,文章提出一种基于Scott平衡变压器同相牵引供电模型下的负载基波有功电流与基波无功电流的改良检测方法,用均值滤波器来替代传统的低通滤波器与单相锁相环来锁定被测电压的相位与频率,从而使检测的基波有功与无功电流更加的准确,理论分析与仿真验证了该方法的可行性与优越性。

single phase current detection method research of cophase traction power supply system

In order to compensate the fundamental wave reactive current and harmonic current accurately in the phase railway load side for making the power factor of three-phase power supply to 1 and achieving the balance of three phase system,the traditional way is to use the characteristics of trigonometric function through the adder,multiplier,integrator and phase-locked loop to realize the fundamental active current and reactive current detection.The methods can avoid a lot of matrix and the inverse matrix calculations,making the low cost of whole operation circuit,which is simple and easy to implement.while there is the single-phase delay of PLL and and low pass filter,thus the lock voltage phase will deviation at the beginning and having a impact on the current dynamic performance of early detection.Based on the above problem,considering the average filter characteristic of rapid detection performance,this paper presents an improved method of detecting the fundamental active current and fundamental reactive current of the load under the Scott balance transformer power supply system,using the average filter with good dynamic response speed to replace the traditional low-pass filter and single-phase PLL to lock in the phase of the voltage and frequency measured.The analysis of theory and simulation verify that the method is more accurate and superior than the effects of traditional ways.