Description

Method to determine angular speed in a mechanically commutated motor by only measuring the current flowing within it (Patent for invention request number 200902143). This method is based on determining the moments when alternating component waveforms happen. From this data, the ripple frequency value is estimated and, using it, the motor's angular speed. Both magnitudes are directly linked because, for every engine rotation, a specific number of waveforms appears in the current, which depends on the number of motor poles and bars. By waveform we mean each period of the current alternating component. Waveform detection is by wavelength shift record, where motor current's last waveforms are collected. If the current's maximum value is in the record's central position, the peak has just been detected and, therefore, the waveform is also detected by registering the moment where it has been spotted. Depending on the wavelenght value, current noise can be filtered out to a greater or lesser extent.

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