CN106208542A - A kind of permanent-magnet synchronous motor rotor surface temperature measurement device - Google Patents

Abstract

A permanent magnet synchronous motor rotor surface temperature measurement device, including a plurality of optical fiber probes, infrared temperature sensors corresponding to the optical fiber probes, and an analysis and processing module. The optical fiber probes are buried in the stator slot of the motor. The radial direction of the motor rotor is the same, and each fiber optic probe is connected to a corresponding infrared temperature sensor through an optical fiber, and the infrared temperature sensor is connected to an analysis and processing module. The invention collects the infrared rays emitted by the rotor itself inside the permanent magnet synchronous motor to judge and analyze the temperature field of the rotor in the motor, so as to facilitate the research on the temperature field of the permanent magnet synchronous motor and ensure the highest use efficiency of the motor in a safe state.

Description

A permanent magnet synchronous motor rotor surface temperature measuring device

technical field

The invention relates to a temperature measuring device, in particular to a permanent magnet synchronous motor rotor surface temperature measuring device.

Background technique

The permanent magnet synchronous motor has high power factor and high efficiency, and gradually replaces the AC asynchronous motor in many occasions. At present, a few developed countries have begun to use permanent magnet synchronous traction motors as the power source for high-speed railways. CSR Zhuzhou Electric Locomotive Research Institute Co., Ltd. also broke through this problem and successfully delivered it to Changsha Metro Line 1. In order to prevent water, dust, iron filings, etc. from corroding the permanent magnet inside the motor, the permanent magnet motor adopts a fully enclosed structure. Since the permanent magnet traction motor used in rail transit usually has a power of more than 500KW and generates a lot of heat, the permanent magnet material in the motor rotor may lose its magnetism under severe conditions such as high temperature. Once the train loses magnetism when running at high speed, it will lose the ability of regenerative braking, and the braking distance may be as long as nearly 100 kilometers. Temperature control is the bottleneck in the use of permanent magnet synchronous traction motors. The rotor part of most permanent magnet motors is mainly composed of permanent magnets, rotor cores, rotor pressure rings, and heat dissipation ribs, without coils; the stator part mainly includes stator windings, stator cores, and does not contain permanent magnets. At present, there are very few devices for measuring the temperature of the inner rotor of a permanent magnet synchronous motor in operation. Some other patent applicants proposed to arrange an infrared thermometer in the motor, but the motor is in a strong electromagnetic interference environment, especially for high-power traction motors, the electronic circuit may not work, and the small space in the motor also poses a problem for the safety sensor. Here comes the problem.

Contents of the invention

Aiming at the bottleneck encountered in the use of the above-mentioned permanent magnet synchronous traction motor, the present invention provides a permanent magnet synchronous motor rotor surface temperature measuring device,

In order to achieve the above object, the present invention adopts the following technical solutions:

A permanent magnet synchronous motor rotor surface temperature measurement device, including a plurality of optical fiber probes, infrared temperature sensors corresponding to the optical fiber probes one-to-one, and an analysis and processing module,

The optical fiber probes are buried in the stator slot of the motor. The axial direction of the optical fiber probes is the same as the radial direction of the motor rotor. Each optical fiber probe is connected to the corresponding infrared temperature sensor through the optical fiber, and the infrared temperature sensor is connected to the analysis and processing module.

The optical fiber probes are installed equidistantly along the axial direction of the motor, and the optical fiber probes are evenly distributed in the circumferential direction.

Compared with the prior art, the present invention has the beneficial effects:

The invention collects the infrared rays emitted by the rotor itself inside the permanent magnet synchronous motor to judge and analyze the temperature field of the rotor in the motor, so as to facilitate the research on the temperature field of the permanent magnet synchronous motor and ensure the highest use efficiency of the motor in a safe state.

Description of drawings

Fig. 1 is a structural principle block diagram of the motor rotor temperature measuring device of the present invention.

Figure 2 is a diagram of the internal structure of the permanent magnet synchronous motor.

Figure 3 is a schematic diagram of the axial installation position of the fiber optic probe.

Fig. 4 is a schematic diagram of the circumferential installation position of the fiber optic probe.

In the figure, 1. Optical fiber probe, 2. Stator slot, 3. Cooling fan, 4. Stator core, 5. Stator winding, 6. Rotor, 7. Rotating shaft, 8. Machine base.

detailed description

The technical solution of the present invention will be further elaborated below through examples.

Example 1

A permanent magnet synchronous motor rotor surface temperature measuring device, including a plurality of optical fiber probes 1, infrared temperature sensors corresponding to the optical fiber probes one-to-one, and an analysis and processing module,

The fiber optic probe 1 is buried in the stator slot 2 of the motor, the axial direction of the fiber optic probe 1 is the same as the radial direction of the motor rotor, and each fiber optic probe is connected to the corresponding infrared temperature sensor through an optical fiber, and the infrared temperature sensor is connected to the analysis processing module.

The optical fiber probes are installed equidistantly along the axial direction of the motor, and the optical fiber probes are evenly distributed in the circumferential direction.

Example 2

Assume a 9-slot, 8-pole three-phase permanent magnet synchronous motor with a rotor length of 500 mm, a diameter of 400 mm, and an angle between adjacent slots of 40 degrees. In this embodiment, 9 probes and 9 infrared temperature sensors are used to monitor the temperature field distribution of the motor rotor.

The distribution positions of the probes are shown in attached drawings 3 and 4. The probes are installed in the slot of the motor stator. The optical fiber probes start from one end of the motor and rotate every 80 mm along the axis. Both ends are installed and adjacent to each other. The two probes are 40 degrees apart in the same direction in the circumferential direction.

When the motor stator rotates, the optical fiber probe collects the infrared rays emitted from the surface of the stator and transmits them through the optical fiber. The optical fiber is buried in the wire groove together with the winding coil of the motor, and finally reaches the 9 infrared temperature sensors outside the motor. The infrared sensor measures the temperature in the motor according to the set sampling frequency. The sampling frequency needs to be staggered with the motor speed. If the speed of the motor is 3000 revolutions per minute, that is, 50 revolutions per second, the sampling frequency cannot be 50hz, and it is recommended to set it to 48hz or 52hz.

The collected temperature field values are input to the processing module for processing, and the finite values are fitted to a continuous temperature field distribution to determine whether the permanent magnet has a risk of demagnetization.

working principle:

In the stator of the permanent magnet synchronous motor, a plurality of optical fiber probes are uniformly arranged along the axial direction, and the axis of the optical fiber probes is along the radial direction of the rotor. The optical fiber probe transmits the infrared rays received from the surface of the rotor to the infrared temperature sensor outside the motor through the optical fiber. The infrared temperature sensor converts them into electrical signals and enters the analysis module for sorting and analysis. The analysis results can be used for research or as feedback signals Guide the control of the motor.

The optical fiber led by the fiber optic probe is buried in the wire slot of the stator together with the stator coil of the motor, and passes through the threading hole of the motor casing to reach the outside of the motor. Multiple optical fibers are integrated into the optical fiber bundle and enter the processing module outside the motor. Each optical fiber is respectively connected to an infrared temperature sensor. The infrared temperature sensor converts the received infrared signal into an electrical signal and transmits it to the analysis module for analysis and analysis. deal with.

The continuous distribution of the temperature field in the direction of the motor axis is fitted by a finite number of sensors, and the fitting accuracy is related to the number of sensors. Because the motor rotor is made of metal material, which has good thermal conductivity and small gradient of temperature field, it is considered that only a few of them can be arranged in the axial direction to meet the accuracy requirements. During the working process of the motor, the rotor rotates around the axis. During one rotation of the rotor, a single sensor completes the temperature measurement of a circle on the outer surface of the rotor. Using multiple measured temperature values on the circumference, the temperature field of the entire outer surface of the rotor is obtained through interpolation calculation.

Since the probes have a certain volume, different probes are not only equidistantly distributed along the axis of the motor, but also staggered by a certain angle along the circumferential direction of the motor, so as to reduce the influence of the arrangement of probes on the stator coil of the motor.

Claims (2)

1. A permanent magnet synchronous motor rotor surface temperature measuring device is characterized in that it comprises a plurality of optical fiber probes, an infrared temperature sensor corresponding to the optical fiber probes one by one and an analysis and processing module, The optical fiber probes are buried in the stator slot of the motor. The axial direction of the optical fiber probes is the same as the radial direction of the motor rotor. Each optical fiber probe is connected to the corresponding infrared temperature sensor through the optical fiber, and the infrared temperature sensor is connected to the analysis and processing module. 2. The temperature measuring device according to claim 1, wherein the optical fiber probes are installed equidistantly along the axial direction of the motor, and the optical fiber probes are also uniformly distributed in the circumferential direction.