旋转变压器滑模变结构数字转换算法研究

旋转变压器的两路输出均为包含角位置信息的调幅信号,必须进行解调,以实现模拟调制信号到数字信号的转换。在旋转变压器数字转换器中,常采用锁相环作为核心的解调算法。然而,常规锁相环只是一个典型的二型跟踪环路,难于兼顾动态与稳态的性能,尤其是当被测角位置高动态变化时,解调误差较大。为提高解调精度,将旋转变压器数字转换问题转化为角度跟踪控制问题,提出了一种基于滑模变结构控制器的旋转变压器数字转换算法。该算法引入了切换控制项,可以抑制被测角位置高动态变化所导致的模型不确定性对解调精度的影响。实验结果表明,该方法是可行的。

Sliding-mode variable-structure algorithm for resolver-to-digital conversion

As the outputs of resolvers are amplitude-modulated signals containing angular position information, demodulation is necessaryto convert analog modulated signals to digital ones. In resolver-to-digital converters, phase locked loop (PLL) is usually adopted as thealgorithm for demodulation. However, conventional PLL is only a classical type-II tracking loop which cannot overcome the contradictionbetween dynamical and steady-state performance. Especially for the measured angular position with high dynamic variations, thedemodulation error is often large. In order to improve the demodulation accuracy, the problem of resolver-digital conversion istransformed into the problem of angle tracking control, and a sliding-mode variable-structure demodulation algorithm is proposed. Thisalgorithm can retrain the effects of the model uncertainties on demodulation accuracy caused by speed variation by using switching controlterm. Experimental results show that the proposed algorithm is feasible.