Position sensorless control method and device for long-line driving permanent magnet motor

Abstract

The invention discloses a position sensorless control method and device for a long-line drive permanent magnet motor. The method comprises the steps: adding a coupling circuit behind a transformer ina long-line driving circuit of the permanent magnet motor; enabling three high-frequency detection signals with different frequencies to be respectively coupled into a motor power line and a winding through three transformers in a coupling circuit, and then obtaining high-frequency voltage components at the primary sides of the three transformers through a band-pass filter; obtaining a position signal according to the effective value relation of the high-frequency voltage components, and achieving the sensorless control over the motor according to the position signal through the controller. The method overcomes the defects that a counter potential method is poor in control effect at a low speed and a zero speed and a traditional inductance method cannot be used in a long-line drive motor,expands the motor speed regulation range, and improves the rotor position detection precision. The method facilitates the more precise control of the motion of the permanent magnet motor, avoids the use of a voltage sensor, reduces the system cost, and reduces the system size.

Description

technical field [0001] The invention relates to a drive of a permanent magnet motor. In particular, it relates to a position sensorless control method and device for long-line drive permanent magnet motors. Background technique [0002] Permanent magnet motors are widely used in industry because of their high power density, large output torque and high efficiency. A trend in the petroleum industry is to replace asynchronous motors with permanent magnet motors to improve efficiency, reduce energy consumption, and reduce the overall size of the motor at the same power level. The core of the electric submersible pump used in oil production in the petroleum industry is the long-line drive permanent magnet motor. The long-line drive motor is characterized by a large line voltage drop. When the power supply voltage is transmitted to the motor port through a long line, it has not reached the rated operating voltage of the motor. Requirements, so there will be a step-up transforme...

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Problems solved by technology

[0004] The high-frequency detection signal in the traditional inductance method is generated by the power switch, but in the permanent magnet motor long-line drive, the high-frequency detection signal generated by the power switch is greatly suppressed when it passes through the step-up transformer in the line, and most of the signal energy Transformed into heat energy consumption, it does not act on the motor windings, and the position signal of the rotor cannot be obtained

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