METHOD OF MEASURING VARIATIONS IN RESISTIVE TORQUE FOR ELECTRICAL ENGINES

摘要

As it is known, the derivative of a received signal is usually obtained by filtering the received signal (using low-pass filters) and by dividing the difference between the filtered values of the signal at two different moments of time at the time difference between these time moments. Many times these filtering and sampling devices consists of low-pass filters represented by asymptotically stable systems, sometimes an integration of the filter output over a certain time interval being added. However, such a structure is very sensitive at random variations of the integration period, and so it is recommended the signal which is integrated to be approximately equal to zero at the end of the integration period. It will be shown that the simplest structure with such properties is represented by an oscillating second order system working on a time period, and it will be also shown how such a structure can be used for obtaining the derivative of the received signal with higher accuracy.