CN-115864931-B - Permanent magnet generator no-load loss separation method and device

CN115864931BCN 115864931 BCN115864931 BCN 115864931BCN-115864931-B

Abstract

The invention discloses a method for separating no-load loss of a permanent magnet generator, which comprises the steps of under normal pressure, dragging a generator to rotate by a motor on a opposite dragging test platform, measuring the input power of the generator by using a magnet of the generator without magnetizing, marking as P1, measuring the input power of the generator by using a magnet of the generator with magnetizing, marking as P3, measuring the input power of the generator by using a magnet of the generator without magnetizing in a vacuum environment, marking as P2, replacing a three-phase winding of the generator with a non-conductive material, measuring the input power of the generator, marking as P4, measuring the sum of heat at two ends of a rotating shaft of the generator in the vacuum environment, marking as P5, coating low infrared emissivity coatings on the inner surface of a fixed part and the outer surface of a rotating part of the generator, and calculating to obtain rotor wind friction loss Pfr=Pf1-P2, winding copper loss Pwi =P3-P4, rotor eddy current loss Ped=P5, and stator core loss PFe=P4-P1-P5. The invention also discloses a device for separating the no-load loss of the permanent magnet generator. The invention can realize accurate measurement of various losses.

Inventors

ZHU ZICHONG
DENG JUN
ZHANG GUANGMING
OUYANG HUIMIN

Assignees

南京工业大学

Dates

Publication Date: 20260512
Application Date: 20221108

Claims (6)

1. The no-load loss separation method of the permanent magnet generator is characterized by comprising the following steps of: Step 1, under the normal pressure environment, a motor drags a generator to rotate on a opposite-dragging test platform, the input power of the generator is measured and recorded as P1, a magnet of the generator is not magnetized in the step, and a three-phase winding of the generator is in an open-circuit idle state; step 2, under a vacuum environment, dragging a generator to rotate by a motor on a opposite-dragging test platform, measuring the input power of the generator, and recording as P2, wherein a magnet of the generator is not magnetized in the step, and a three-phase winding of the generator is in an open-circuit idle state; step 3, under the normal pressure environment, on a opposite-dragging test platform, a motor drags a generator to rotate, the input power of the generator is measured and recorded as P3, a magnet of the generator is magnetized in the step, and a three-phase winding of the generator is in an open-circuit idle state; Step 4, under a vacuum environment, dragging a generator to rotate by a motor on a opposite-dragging test platform, measuring the input power of the generator, and recording as P4, wherein a magnet of the generator is magnetized in the step, and a three-phase winding of the generator is replaced by a non-conductive material; Step 5, under a vacuum environment, dragging the generator to rotate by the motor on the opposite-dragging test platform, measuring the sum of heat at two ends of a rotating shaft of the generator, and recording as P5, magnetizing a magnet of the generator in the step, wherein a three-phase winding of the generator is in an open-circuit no-load state, and the inner surface of a fixed part and the outer surface of a rotating part of the generator are coated with low-infrared-emissivity coatings; the bearing loss is Pbr, pbr=p2, and rotor wind friction loss pfr=p1-pbr=p1-P2, winding copper loss Pwi =p3-P4, rotor eddy current loss ped=p5 and stator core loss pfe=p4-P1-P5 are calculated.
2. The method according to claim 1, wherein the heat at two ends of the rotating shaft of the generator in the step 5 is obtained by calculating the temperatures measured by temperature sensors respectively disposed at two ends of the rotating shaft of the generator at a set distance, wherein the heat q1=kχ a (T2-T1)/L1 at the front end of the rotating shaft, the heat q2=kχ a (T4-T3)/L2 at the rear end of the rotating shaft is the heat conductivity coefficient of the rotating shaft material, a is the cross-sectional area of the rotating shaft, T1, T2 are the temperatures measured by the temperature sensors at the front end of the rotating shaft, L1 is the distance between the temperature measuring points of the temperature sensors at the front end of the rotating shaft, T3, T4 are the temperatures measured by the temperature sensors at the rear end of the rotating shaft, and L2 is the distance between the temperature measuring points of the temperature sensors at the rear end of the rotating shaft.
3. The method according to claim 1, wherein the input power of the generator measured in steps 1 to 4 is an input torque Ts of the generator measured by a torque sensor, and the input power p=ts×n, n is a rotation speed of the rotating shaft of the generator.
4. The utility model provides a permanent magnet generator no-load loss separator which characterized in that includes five pair drags test platform and calculation portion, five pair drags test platform includes: the system comprises a first platform, a second platform and a third platform, wherein the first platform is used for measuring the input power of a generator under the normal pressure environment, a magnet of the generator of the first platform is not magnetized, and a three-phase winding of the generator is in an open-circuit idle state; The second platform is used for measuring the input power of the generator in a vacuum environment and comprises a vacuum box, the generator and the motor of the opposite-dragging test platform are arranged in the vacuum box, the magnet of the generator of the second platform is not magnetized, and the three-phase winding of the generator is in an open-circuit and no-load state; the third platform is used for measuring the input power of the generator in a normal pressure environment, a magnet of the generator of the third platform is magnetized, and a three-phase winding of the generator is in an open-circuit idle state; the fourth platform is used for measuring the input power of the generator in a vacuum environment and comprises a vacuum box, the generator and the motor of the opposite-dragging test platform are arranged in the vacuum box, the magnet of the generator of the fourth platform is magnetized, and the three-phase winding of the generator is made of non-conductive materials; the fifth platform is used for measuring heat at two ends of a rotating shaft of the generator in a vacuum environment and comprises a vacuum box, the generator and the motor of the opposite-dragging test platform are arranged in the vacuum box, a magnet of the generator of the fifth platform is magnetized, a three-phase winding of the generator is in an open-circuit idle state, and the inner surface of a fixed part and the outer surface of a rotating part of the generator are coated with low-infrared-emissivity coatings; The calculation section is used for realizing the permanent magnet generator no-load loss separation method according to any one of claims 1 to 3.
5. The permanent magnet generator no-load loss separation device according to claim 4, wherein the generators in the five split test platforms are coupled with the rotating shafts of the motors through couplings and torque sensors, and the torque sensors are used for measuring the rotating shaft torque of the generators to calculate the input power.
6. The permanent magnet generator no-load loss separation device according to claim 4, wherein temperature sensors in the fifth platform are spaced at set distances at two ends of the rotating shaft of the generator, and the temperatures measured by the temperature sensors are used for calculating heat at two ends of the rotating shaft of the generator in the fifth platform.

Description

Permanent magnet generator no-load loss separation method and device Technical Field The invention relates to a generator loss separation method, in particular to a permanent magnet generator no-load loss separation method and device, and belongs to the technical field of generators. Background The permanent magnet motor has the outstanding advantages of high power density, high efficiency, good dynamic characteristics and the like, and is widely applied to electric spindles, novel flywheel energy storage and gas turbine power generation systems. The rotor magnetic field of the permanent magnet generator is established by the permanent magnet, and various losses exist in the operation process. First, there is wind friction between the rotor member and the surrounding medium (air in a general working environment) during high-speed rotation, and the size of the rotor member is related to factors such as rotation speed, physical properties of the medium, surface roughness of the rotating member, and the like, and there is no wind friction in a high-vacuum environment. Meanwhile, the rotating part is connected with the fixed part through a bearing, balls or rolling pins exist between inner and outer channels of the bearing, and friction loss exists in the rotating process. In addition to the rotational speed effects, the bearing losses are also related to their own characteristics. Second, permanent magnet motor stator cores are typically fabricated from high permeability materials, such as non-oriented electrical steel, in which alternating magnetic fields produce a substantial proportion of iron loss. In addition, for higher frequency permanent magnet motors, the motor winding material is exposed to alternating leakage fields. Due to the skin effect, eddy currents exist in the conductor, and additional losses are generated in the windings under both idle and load conditions. Finally, under the influence of space harmonics, tooth harmonics and current time harmonics, a certain harmonic magnetic field exists on the rotor, and more rotor eddy current loss is induced in the conductive component. The losses often occur simultaneously in permanent magnet motors and are distributed in a dispersed manner over the electromagnetic components, and it is difficult to directly measure and separate the losses by means of simple instruments. At present, the mechanical loss and the electromagnetic loss of the motor can be separated by a pseudo-rotor method and a natural speed reduction method, but the components in the mechanical loss and the electromagnetic loss still have no effective and accurate separation method. Therefore, in practical engineering application, the performance test can only obtain the total loss and the comprehensive efficiency of the motor or the generator, and cannot analyze the influence of various losses independently. In the motor design process, the actual test results of various losses are required to carry out test verification on the related model and the calculation method. The verification work of the loss calculation model still lacks a feasible path because of the inability to accurately measure and separate various losses. Further, due to the lack of reliable loss models and test data, link accuracy in optimizing electromagnetic parameters according to test results in the design process is reduced. Disclosure of Invention In order to overcome the defects in the prior art, the invention provides a method for separating the no-load loss of a permanent magnet generator, which solves the problem that various losses of the generator are difficult to separate and determine independently. The invention also provides a device for separating no-load loss of the permanent magnet generator. The technical scheme of the invention is as follows, the no-load loss separation method of the permanent magnet generator comprises the following steps: Step 1, under the normal pressure environment, a motor drags a generator to rotate on a opposite-dragging test platform, the input power of the generator is measured and recorded as P1, a magnet of the generator is not magnetized in the step, and a three-phase winding of the generator is in an open-circuit idle state; step 2, under a vacuum environment, dragging a generator to rotate by a motor on a opposite-dragging test platform, measuring the input power of the generator, and recording as P2, wherein a magnet of the generator is not magnetized in the step, and a three-phase winding of the generator is in an open-circuit idle state; step 3, under the normal pressure environment, on a opposite-dragging test platform, a motor drags a generator to rotate, the input power of the generator is measured and recorded as P3, a magnet of the generator is magnetized in the step, and a three-phase winding of the generator is in an open-circuit idle state; Step 4, under a vacuum environment, dragging a generator to rotate by a motor on a opposite-dragging test platform, meas