Motor encoder power supply method and system taking power from neutral point of output end of frequency converter

Abstract

The invention discloses a motor encoder power supply method and system taking power from a neutral point of the output end of a frequency converter and belongs to the field of alternating current motors and drive control. The method comprises steps of improving a common-mode voltage waveform at a neutral point of a motor stator winding through a zero-free vector pulse width modulation method so that a common-mode voltage is converted into two levels from four levels; rectifying the suppressed common-mode voltage, and converting the two-level common-mode voltage into a direct-current voltage; and carrying out voltage conversion on the rectified direct current voltage, converting the direct current voltage into a voltage level required by encoder power supply, and then supplying power to theencoder. According to the method, a direct-current weak-current power supply cable led out for supplying power to the encoder is omitted so that the electrical connection between the motor and the frequency converter is simpler, and a problem of encoder power supply cable winding of motors such as industrial robots and the like in application occasions of multi-degree-of-freedom spatial motion isavoided, operation flexibility of the equipment is improved, meanwhile, a stable power supply can be provided for the encoder under different operation conditions of the motor.

Description

technical field [0001] The invention belongs to the field of AC motors and drive control, and more specifically relates to a motor encoder power supply method and system for taking power from a neutral point at an output end of a frequency converter. Background technique [0002] The servo system refers to the execution system that can quickly and accurately follow the position, speed, torque and other instructions issued by the control mechanism, also known as the servo system. The servo motor is the actuator of the servo system and the core component of the whole system. Its performance is directly related to the performance of the whole servo control system. Any high-performance servo motor contains a key component, the encoder. [0003] When the encoder is working, the diode emits light and detects and processes the signal, which is used to measure the real-time position and speed of the electrode rotor. To complete these tasks, an additional DC power supply cable is re...

AI Technical Summary

Problems solved by technology

However, since the energy source of electric energy is the kinetic energy of the rotating shaft, when the motor is at low speed or even stops, the kinetic energy of the rotating shaft is very small, and it is difficult for the encoder to obtain sufficient power supply, which leads to problems such as power failure. This defect restricts the Wiegand effect self-power supply development of encoders

[0005] Another solution is to take power from the three-phase drive bus at the motor input end. The power processing part of this solution is more complicated, and the insulation performance and sealing performance of the motor will be affected, which will destroy the balance of the power supply, so it is rarely used.

Images