A method and topology for testing the main insulation and turn-to-turn insulation of variable frequency motors

Abstract

The invention discloses a method for testing the main insulation and inter-turn insulation of a low-voltage loose-wound variable-frequency motor. S3 The boosted voltage signal is transmitted through the shared high-voltage bus, and the test branch is switched by changing the state of the switching relay; S4 When the inter-turn insulation is tested, the high-frequency pulse signal generated is used to pressurize the variable frequency motor winding , using the pulse signal to test the inter-turn insulation; when testing the main insulation, the sinusoidal voltage signal transmitted by the common high-voltage bus is used to pressurize the winding of the variable frequency motor, and the motor casing is grounded, and the main insulation is tested using the sinusoidal signal. The invention also provides a topological structure for testing the main insulation and inter-turn insulation of the low-voltage random-winding variable-frequency motor. The invention can realize common testing of main insulation and inter-turn insulation in the same testing system by sharing the high-voltage bus, reduces experimental steps and experimental equipment, and greatly improves experimental efficiency.

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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