Method for testing main insulation and turn-to-turn insulation of variable frequency motor and topological structure

Abstract

The invention discloses a method for testing main insulation and turn-to-turn insulation of a low-voltage scattered-wound variable frequency motor, and the method comprises the steps: S1, inputting 0-220V AC voltage, and carrying out the voltage regulation of the AC voltage; s2, boosting the voltage signal after voltage regulation; s3, transmitting the boosted voltage signal through a common high-voltage bus, and switching a test branch by changing the state of a switching relay; s4, when the turn-to-turn insulation is tested, increasing the voltage, by using the generated high-frequency pulse signal, of the variable frequency motor winding, and testing the turn-to-turn insulation by means ofthe pulse signal; when the main insulation is tested, boosting, by using the sine voltage signal transmitted by the common high-voltage bus, the variable frequency motor winding, and grounding the motor shell, and testing, by using the sine signal, the main insulation. The invention further provides a topological structure for testing the main insulation and the turn-to-turn insulation of the low-voltage scattered-wound variable frequency motor. According to the invention, by sharing the high-voltage bus, the main insulation and the turn-to-turn insulation can be jointly tested in the same test system, the experiment steps and the experiment equipment are reduced, and the experiment efficiency is greatly improved.

Description

technical field [0001] The invention relates to the technical field of variable frequency motors, in particular to a method and topological structure for testing main insulation and inter-turn insulation of variable frequency motors. Background technique [0002] As a power source, variable frequency motors are widely used in wind power generation, high-speed railways, new energy vehicles and ship drives. The stator of the variable frequency motor is subjected to high-frequency and rapidly changing pulse width modulation voltage. Under the action of the distributed inductance and capacitance parameters of the stator winding, the insulation system is prone to voltage concentration. When the voltage exceeds the partial discharge initiation voltage (PDIV), the winding in the winding Partial discharge occurs, which accelerates insulation aging and leads to early failure of insulation. At the same time, the copper loss, hysteresis loss and eddy current loss of the motor stator a...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a method and topological structure for testing the main insulation and turn-to-turn insulation of variable frequency motors, which mainly solves the problem that the same system cannot be used to test the main insulation and turn-to-turn insulation of low-voltage random-wound variable-frequency motors in the prior art. And it solves the problems of too many steps, cumbersome operation, and too long test time when performing a complete inspection of the inter-turn of the variable frequency motor and the insulation of the ground.

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