Method for realizing on-site estimation on temperature of rotor magnetic steel of permanent magnet motor

Abstract

The invention relates to a method for realizing on-site estimation on a temperature of rotor magnetic steel of a permanent magnet motor. The method comprises the following steps that: under the circumstances that a three-phase wire of a permanent magnet motor is kept away from a motor controller, cooling liquid for the permanent magnet motor is controlled to keep the temperature to be constant and a corresponding relation between a rotor temperature change and a rotating speed as well as a stator temperature on the condition of a phase-free current is obtained by recoding test data and carrying out corresponding processing; the three-phase wire of the permanent magnet motor is kept to be connected with the motor controller and corresponding relations between the rotor temperature changes and phase currents as well as stator temperatures on the condition of different phase currents are obtained by recording test data and carrying out corresponding processing under the condition of normal cooling; the data that are obtained by the above-mentioned steps are compared and processed so as to obtain corresponding relations between the rotor temperatures and the phase currents, the stator temperatures, and the rotating speeds and the corresponding relation information is stored into the motor controller of the permanent magnet motor, wherein the motor controller has the identical type with the permanent magnet motor. According to the invention, the rotator temperature change can be monitored in real time to prevent that the temperature of the rotor magnetic steel is too high, thereby improving the security performance of a driving system.

Description

【Technical field】 [0001] The invention relates to the technical field of motor temperature control, in particular to a method for realizing on-line estimation of the temperature of the rotor magnetic steel of a permanent magnet motor. 【Background technique】 [0002] The permanent magnet motor is a key component that combines technologies in various fields such as electricity, magnetism, mechanics, and heat. Especially, the high-efficiency and high-density permanent magnet motor has been widely used in electric vehicles. Thermal performance analysis is very important for permanent magnet motors, because it will not only affect the output characteristics of permanent magnet motors, but more seriously, it may damage the motor under certain excessive temperature conditions. In this regard, in the prior art, a temperature sensor is usually installed on the motor stator, and the temperature of the stator is fed back to the motor controller for temperature monitoring processing. H...

AI Technical Summary

Problems solved by technology

However, the actual situation is that it is not enough to monitor the stator temperature of the motor, because there is an air gap between the stator and the rotor, and it will cause the information collected by the stator temperature sensor to not directly reflect the actual temperature of the rotor

If the rotor temperature is too high, it will directly affect the performance of the permanent magnet, and may eventually lead to demagnetization of the permanent magnet

However, since the motor rotor is a rotating body, the temperature cannot be measured in real time, so how to obtain the temperature value of the motor rotor is indeed a very challenging task

[0003] In the Chinese patent literature with the publication number CN101275871A, a method for measuring the temperature distribution of the rotor of a high-speed rotating permanent magnet synchronous motor is disclosed, although in this method, by drilling holes on the stator teeth and fixing the infrared temperature sensor in the hole, the sensor The probe is directly opposite to the rotor surface, and the frequency converter is used to reduce the high-speed rotating rotor below the critical measurement speed in a short time and run stably, and then record the average surface temperature of the rotor measured by the sensor during the deceleration process through the data acquisition system change and the temperature distribution of the rotor surface during stable operation below the critical measurement speed and adding them together can obtain the temperature distribution of the rotor during high-speed rotation, but the above method cannot estimate the rotor magnet temperature of the permanent magnet motor online in real time

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