Motor heat protection method

Abstract

The invention provides a motor heat protection method comprising the following steps of: obtaining a winding temperature by calculating loss parameters of the motor winding and an iron core; limiting the amplitude of an output current when the winding temperature increases to a permissible insulation temperature until the current is zero, and prohibiting the output of pulse width modulation; and increasing the limit amplitude of the current when the winding temperature is lower than the permissible insulation temperature and reaches a lower limit value. The motor heat protection method implements effective heat protection to a permanent magnetic synchronous electric motor, controls the operation according to the winding temperature and the operation conditions, improves the operation service life and the reliability of the electric motor and stimulates the application of the permanent magnetic synchronous electric motor to a high-precision high-performance servo system.

Description

technical field [0001] The invention relates to the field of motor protection, and in particular to a motor thermal protection method applied in the field of servo control of permanent magnet synchronous motors to realize thermal protection and intelligent control operation of the motor. Background technique [0002] The thermal protection of the motor is usually to set a thermal protection relay inside the motor. The bimetal sheet (thermal sensor) of the thermal relay directly or indirectly senses the current of the winding and the current generated by the temperature sensing element near the winding. When the current and time When the relationship is above the inverse time characteristic curve of thermal protection, the bimetal sheet is heated and deformed and drives the contact action of the thermal relay, the power supply is cut off, and the motor stops; when the bimetal sheet is naturally cooled below a certain temperature, the thermal relay's The contacts are reversed ...

AI Technical Summary

Problems solved by technology

[0003] However, the existing technology has the following disadvantages: ① a thermal protection device is installed separately inside the motor, which takes up a certain space and cannot be applied to permanent magnet synchronous motors with high power density, small size and light weight; ② adopts relay protection, On-site thermal protection setting is required, and it is not easy to perform proper setting; ③The reliability of the device is poor, the life is short, and it is easy to age and lose its protective effect; ④It is impossible to perform thermal protection and operation control according to the requirements of winding temperature and operating conditions

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