Method and device for measuring rotating speed of motor

Abstract

The invention provides a method and a device for measuring a rotating speed of a motor. The measurement device consists of an incremental photoelectric coded disk, a programmable logic controller, a digital signal processor and a data address bus, wherein the digital signal processor realizes functions of sending a command, checking a state, reading data, calculating the speed and the like; and the programmable logic controller is connected with the digital signal processor through the data address bus. In the measurement method, the rotating speed of the motor is measured by a frequency periodic method (M / T); an orthogonal encoded pulse signal for introducing a position quantization error is defined as a false pulse; by a digital filter method and a direction-based signal identification method, the false pulse is eliminated; and the programmable logic controller is used for realizing functions of decoding the orthogonal pulse, counting the pulse, eliminating the false pulse, catchinga counted value and the like.

Description

technical field [0001] The invention belongs to the technical field of motor control, and relates to a motor speed detection method and a detection device in a rotating motor speed control system, in particular to a motor speed control system using an incremental photoelectric code disc as a sensor. Background technique [0002] In the motor speed control system, the measurement of the speed is crucial for the speed feedback control. In order to find a balance between measurement accuracy and system cost, incremental photoelectric encoders are widely used. Among the rotational speed measurement methods using incremental photoelectric code discs as sensors, frequency method, period method and frequency period method are commonly used. The frequency method measures the rotational speed by counting the output pulses of the incremental photoelectric code disc within a fixed measurement period. It is characterized by high measurement accuracy at high speeds, and rapidly decrease...

AI Technical Summary

Problems solved by technology

In the speed calculation of the frequency cycle method, c, d, e type false pulses will not introduce quantization errors in angle position capture values ​​due to the offset of positive and negative pulses, and thus will not cause speed calculation errors; a, b type false pulses Pulse, due to the particularity of the moment of occurrence, introduces an angular position capture value error of ±1 pulse, the existing frequency cycle method and figure 1 , figure 2 The technical scheme shown obtains the rotational speed through the digital differentiation of the angular position, and the error of the angular position measurement will inevitably lead to the error of the calculated value of the rotational speed

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