基于反余弦法的高精度检相器研究

Research on a Precise Phase Detector Based on Arc Cosine Method

高速磁浮列车的直线同步电机要求精确相位信息．但是磁浮列车悬浮间隙并非恒定，悬浮间隙波动对相位检测精度影响较大．新检相器采用了两组4线圈的结构形式，每组线圈由两个相距一个齿或槽宽的线圈组成，其电信号相位相差π；两组线圈横向错开，纵向相距半个齿或槽宽，其电信号相位相差π／2．通过三角函数变换将两组线圈的电信号转化为归一化信号，再由归一化信号求反余弦获得直线同步电机相位．实验结果表明，在正常的间隙波动（6～14mm）情况下，新检相器最大输出误差不超过0．8＊（0．57mm），满足直线同步电机的要求．

It is required to get the precise phase of Linear Synchronous Motor （LSM） in High Speed Maglev Train （HSMT ）. But the suspensive gap is not constant and its fluctuation has an effect on precision of phase detector. A new phase detector was designed. And it consisted of two coil sets including four coils . The distance between two coils in every set in direction of travel was a groove or slot width. And the phase difference of their electric signal was π. Two sets didn＇t overlap in lateral direction and the distance between them in direction of travel was half a groove or slot width. And the phase difference of their electric signal was π/2. The phase of LSM got from arc cosine of normalized signal, which their electric signal was transformed into via trigonometric function transform. The experimental results show that in condition of nomal gap fluctuation （6-14 mm）, maximum error of the new phase detector is less than 0.8 degree （0.57mm）, which meets the requirement of LSM.