SinCos coder based method for detecting position and speed

Abstract

The invention discloses an SinCos coder based method for detecting a position and speed, comprising the following steps of: regulating a sine and cosine signal of the SinCos coder, then transmitting to a PG card, converting into a digital value by an AD sampling unit inside the PG card, and computing an accurate position theta r within a subdivided period by an MCU; enabling the sine and cosine signal to pass through a hysteresis loop comparison processing circuit to be converted into an A_PULSE signal and a B_PULSE which are transmitted to a QEP unit inside the PG card and for recording the rotated pulses number N of the SinCos coder; transmitting the rotated pulses number N and the accurate position theta r to the MPU through communication, and obtaining accurate position and speed information through simple computation by the MPU. The method enables a frequency converter to complete drive control under the condition that a synchronous motor is matched with the SinCos coder, and can accurately obtain the position and the speed, thereby showing better control property when an elevator starts at low speed and achieving very good embarkation quality without starting compensation.

Description

Technical field: [0001] The invention relates to the application field of a synchronous motor servo drive with a SinCos encoder in an elevator system, in particular to a method for detecting position and speed based on a SinCos encoder. Background technique: [0002] In the elevator system, in order to ensure the loading quality of the elevator starting, a weighing device is generally used. The weighing device senses the weight of the car (including the load) in advance, and after the variable frequency drive system receives this signal, it pre-compensates the starting torque before starting and releasing the brake, so as to realize a smooth start. The general synchronous traction machine control system obtains the speed and position of the motor through pulse type encoders such as UVW+AB encoder or ABZ encoder. Because the high-precision pulse encoder is very expensive, the accuracy of the pulse encoder generally used is not too high, so that there will be no pulse for a l...

AI Technical Summary

Problems solved by technology

The disadvantage is that it needs to occupy at least two AD sampling units. At the same time, it needs to process the sine and cosine signals and invert the trigonometric function to obtain the precise angle position. This method will take up a lot of calculation time of the MPU, and the loading of the MPU will be very heavy.

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