Method for detecting initial position of rotor of power robot

Abstract

The invention discloses a method for detecting the initial position of a rotor of a power robot. The method comprises the steps of firstly exerting three high-frequency low-voltage pulses on a motor by controlling a driving circuit, utilizing an average current oblique differential method for calculating wire inductance values Lab, Lbc and Lac, comparing the inductance values Lab, Lbc and Lac to determine the section of the position angle of the rotor, controlling an inverter to exert a high-frequency low-voltage pulse again according to the section of the position angle of the rotor, selecting the three optimal detection values in the four current peak value detecting processes for rotational coordinate transformation, and finally determining the initial position angle of the rotor. The method for detecting the initial position of the rotor of a permanent magnet synchronous motor can detect the initial position of the rotor of the permanent magnet synchronous motor quite accurately, and achieve smooth starting of the motor, the implementation process is simple, any motor parameters are not required to be depended on, the measuring result is accurate, and the method has the high engineering practical value.

Description

technical field [0001] The invention relates to a method for detecting the initial position of a rotor of an electric robot. The initial position of the rotor is calculated by transforming rotating coordinates after detecting the inductances of A, B and C phases respectively. Background technique [0002] At present, in robot systems of various structures, the scheme of permanent magnet synchronous motor (PMSM) plays an important role because of its high efficiency. Especially in electric robots and small robots, PMSMs have been more used due to these advantages. Whether the initial position of the rotor can be accurately estimated is a prerequisite for the high-performance control strategy (vector control or direct torque) of the permanent magnet synchronous generator and the realization of position sensorless operation. It is also related to whether the robot can start smoothly and whether it can realize The key issue of maximum torque starting; therefore, the detection o...

AI Technical Summary

Problems solved by technology

Whether the initial position of the rotor can be accurately estimated is a prerequisite for the high-performance control strategy (vector control or direct torque) of the permanent magnet synchronous generator and the realization of position sensorless operation. It is also related to whether the robot can start smoothly and whether it can realize The key issue of maximum torque starting; therefore, the detection of the initial rotor position has always been one of the hot and difficult issues in the engineering and technology circles, especially in electric robots, because the operation of the robot is basically a high-voltage operation, and the detection line is very Danger, if the initial position detection of the rotor is inaccurate, it will cause the electric robot to reverberate and rotate, and as a result, the entire power line and the robot may be damaged due to misoperation, and even cause a high-voltage short circuit in severe cases

[0003] There are two methods to ensure that the motor does not rotate and detect the initial position of the rotor. The current research results are di / dt detection method and high-frequency injection method. The di / dt detection method needs to inject a series of signals with the same amplitude and different directions into the motor. Voltage pulse, detect and compare the magnitude of the corresponding current to estimate the initial position of the rotor, this method is feasible, but if you want to obtain the precise initial position of the rotor, you need to apply multiple voltage pulses in different directions, and the control of the inverter is more complicated; The basic principle of the high-frequency signal injection method is to inject a specific high-frequency voltage signal into the motor, and then detect the corresponding current signal in the motor to determine the initial position of the rotor. Additional hardware circuits such as low-pass filters increase the cost

[0004] The more commonly used method for the initial position of the rotor in engineering is the forced positioning method. This method needs to force the robot to rotate before the robot runs. This is very unreliable and cannot be implemented in electric robots.

In addition to some initial position detection methods, they all need to rely on the driving parameters of the robot, which greatly reduces the accuracy of operation.

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