采样—保持鉴相器锁相调速系统的频率捕捉分析

Analysis of the Frequency Acquisition Process for PLL Speed Control System with Sample-and-hold Phase Detector

文章针对采用采样—保持鉴相器的锁相调速系统 ,根据这类鉴相器直接输出直流电压的特性 ,建立了电动机转速与相差间的非线性关系。在时域空间 ,采用近似的方法 ,首次推导出这类锁相系统的频率捕捉范围 ,并对系统的快捕过程进行了分析。

This paper analyses the frequency capture operation for the PLL speed control system (PLSC) with sample-and-hold phase detector (SHPD). Based on the fact that the output of SHPD is DC voltage, the direct relationship between the phase difference Δ θ and the frequency f is established. The process of the frequency capture is analyzed and the frequency capture range is derived first for this kind of PLSC. The lock-in process is also studied.