Speed Estimation Applying Sinc-filter to a Period-based Method for Incremental Position Encoder

Precise speed estimation and short measurement time delay is compulsory for high-performance electric drives. Rotary incremental position encoders are widely used together with speed estimation techniques such as period-based, frequency-based, constant elapse time, and synchronous-measurement methods. This paper proposes the speed estimation technique, which helps to obtain higher accuracy by means of filtering the results of period-based method using third order Sinc-filter. As the sequence of period-based method estimations has the properties of delta-sigma modulated signal, extra information can be extracted. For the specified measurement time that gives higher accuracy than moving average filter. The developed speed estimation method was tested using experimental setup showing better accuracy compared to conventional methods.