CN111181452B - Compensation method for permanent magnet excitation performance difference in permanent magnet motor mass production - Google Patents
Compensation method for permanent magnet excitation performance difference in permanent magnet motor mass production Download PDFInfo
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- CN111181452B CN111181452B CN202010110889.4A CN202010110889A CN111181452B CN 111181452 B CN111181452 B CN 111181452B CN 202010110889 A CN202010110889 A CN 202010110889A CN 111181452 B CN111181452 B CN 111181452B
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- 238000004804 winding Methods 0.000 claims description 13
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- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 3
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- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P6/00—Arrangements for controlling synchronous motors or other dynamo-electric motors using electronic commutation dependent on the rotor position; Electronic commutators therefor
- H02P6/14—Electronic commutators
- H02P6/16—Circuit arrangements for detecting position
- H02P6/18—Circuit arrangements for detecting position without separate position detecting elements
- H02P6/182—Circuit arrangements for detecting position without separate position detecting elements using back-emf in windings
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/34—Testing dynamo-electric machines
- G01R31/343—Testing dynamo-electric machines in operation
Abstract
The invention belongs to a permanent magnet motor performance compensation method, and particularly relates to a permanent magnet excitation performance difference compensation method in mass production of permanent magnet motors. Which comprises the following steps: step 1, determining the basic principle of the operation performance of a permanent magnet synchronous motor according to induced electromotive force, and judging the difference of permanent magnet excitation performance; and step 2, compensating the permanent magnet excitation performance difference to determine a qualified product. According to the invention, the induced electromotive force is kept unchanged by adjusting design parameters, so that the performance difference of the permanent magnet motor is reduced, even the performance is kept unchanged, the rejection rate of products of motor production enterprises is reduced, and the economic benefit of the enterprises is improved.
Description
Technical Field
The invention belongs to a permanent magnet motor performance compensation method, and particularly relates to a permanent magnet excitation performance difference compensation method in mass production of permanent magnet motors.
Background
The permanent magnet motor has the remarkable advantages of simple structure, reliable operation, small volume, light weight, small loss, high efficiency, flexible and various shapes and sizes, and the like, and is widely applied to various fields of aerospace, national defense, industrial and agricultural production and daily life.
In the design and production process of the permanent magnet synchronous motor, stable and accurate permanent magnet performance parameters are important bases for ensuring the superior performance of the permanent magnet motor. However, the permanent magnet materials produced in mass inevitably generate performance differences, resulting in performance differences of the permanent magnet motor, thereby affecting the application of the permanent magnet motor.
Disclosure of Invention
The invention aims to solve the problems of the permanent magnet motor performance caused by the permanent magnet excitation performance difference in the existing mass production, and provides a compensation method for the permanent magnet excitation performance difference in the mass production of the permanent magnet motor.
In order to achieve the above purpose, the invention adopts the following technical scheme, which comprises the following steps.
And step 1, determining the basic principle of the operation performance of the permanent magnet synchronous motor according to the induced electromotive force, and judging the difference of the permanent magnet excitation performance.
And step 2, compensating the permanent magnet excitation performance difference to determine a qualified product.
Further, in the step 1, the determination of the permanent magnet excitation performance difference of the permanent magnet synchronous motor is realized by measuring the no-load counter electromotive force of the motor, the no-load counter electromotive force is obtained by a reverse dragging method or a minimum current method, and if the |test value-design value|/design value is more than 5%, the difference is indicated in the permanent magnet excitation performance.
Further, the reverse dragging method is to drag the tested motor with the prime motor, do no-load running of the generator under the synchronous rotation speed, measure three line voltages of the output end of the tested motor, and take the average value as no-load counter electromotive force; the prime motor can be selected from three-phase synchronous motors with the same pole number and the same power, and also can be selected from three-phase asynchronous motors with the same pole number and the same frequency, and the frequency of the three-phase asynchronous motors is adjusted to achieve the synchronous rotating speed of the three-phase permanent magnet synchronous motors during the test; synchronous machines or asynchronous machines with different poles and different frequencies can be used, but the synchronous rotating speed of the tested machine is ensured to be reached.
Furthermore, the minimum current method is that the tested machine runs in no-load under the rated voltage and rated frequency until the mechanical consumption is stable, and the external voltage is regulated to minimize the no-load current; the average value of the voltage of the external terminal is the no-load counter electromotive force of the permanent magnet synchronous motor.
In step 2, the difference compensation of the permanent magnet excitation performance is realized by adjusting the number of turns and the wire diameter of each phase of the motor winding in series, and the actual no-load counter electromotive force is close to the design value under the condition that the slot full rate does not exceed the limit value.
Further, if the no-load counter electromotive force of the compensated motor is close to the design value, i.e., |test value-design value|/design value <2%, the motor is confirmed to be a qualified product from the factory.
Further, in the step 2, when the no-load back electromotive force test value of the motor is lower than the design value, it is indicated that the actual remanence of the permanent magnet is lower than the nominal valueB r The method comprises the steps of carrying out a first treatment on the surface of the In order to compensate the magnetic performance which is too low, the motor operability is improved, and the electric load of the motor needs to be increased, namely the number of turns of each phase of winding of the motor in series is increased; in order to ensure that the slot filling rate is unchanged compared with the original design, the wire diameter of the enameled wire is reduced while the number of turns is increased.
When the no-load counter electromotive force test value of the motor is higher than the design value, the number of turns of each phase winding of the motor in series connection should be reduced, and meanwhile, the wire diameter of the enameled wire is increased, so that the actual no-load counter electromotive force is ensured to be as close to the design value as possible.
Compared with the prior art, the invention has the beneficial effects.
The invention provides a compensation method for the permanent magnet excitation performance difference in the mass production of permanent magnet motors, which fully considers that when the performance parameters of the mass production permanent magnets are greatly changed, the induced electromotive force is ensured to be unchanged by adjusting design parameters, so that the performance difference of the permanent magnet motors is reduced, even the performance is kept unchanged, the rejection rate of products of motor production enterprises is reduced, and the economic benefit of the enterprises is improved.
Drawings
The invention is further described below with reference to the drawings and the detailed description. The scope of the present invention is not limited to the following description.
Fig. 1 is a flow chart of a compensation method for permanent magnet excitation performance difference in mass production of permanent magnet motors.
Fig. 2 is a schematic diagram of the no-load back emf determining motor performance.
Fig. 3 is a graph comparing the no-load back emf.
Fig. 4 is a comparison of efficiency and power factor before and after motor compensation.
Detailed Description
As shown in fig. 1, the present invention includes.
1. And judging the permanent magnet excitation performance difference.
Residual magnetic densityB r Is an important index for representing the performance of the permanent magnet material, and the difference of the permanent magnet excitation performance is most obvious in the residual magnetic density. The difference of the permanent magnet excitation performance can be equivalent to the change of the residual magnetic density in a range. The operation performance of the permanent magnet synchronous motor is directly related to the performance of the permanent magnet, and the influence of the residual magnetic density on the performance is reflected by the induced electromotive force.
The relationship between the induced electromotive force and the residual magnetic density of the permanent magnet synchronous motor is as follows.
The difference of the residual magnetic density, namely the difference of the permanent magnet excitation performance, can be reflected by measuring the no-load counter electromotive force of the permanent magnet synchronous motor.
And comparing the test value of the no-load counter electromotive force with the design value, if the test value-design value/design value is more than 5%, indicating that the permanent magnet excitation performance has a difference, influencing the motor performance, and not meeting the factory requirements, and compensating the permanent magnet performance difference.
The measurement was performed by the reverse pulling method. During testing, the motor under test is mechanically connected by a prime mover. The prime motor drags the tested motor to be used as the no-load operation of the generator under the synchronous rotating speed. Measuring the voltage of the outlet terminal of the tested motorU ab ，U bc AndU bc the average value is taken as the no-load back emf line voltage value, and the temperature of the motor stator core at that time and the ambient temperature are recorded.
Comparing the test value of the no-load counter electromotive force with the design value, if the |test value-the design value| >5%, the principle that the permanent magnet excitation performance is different and the permanent magnet excitation performance and the motor performance are judged through the no-load counter electromotive force is as follows:
the expression of the alternating current and the direct current of the permanent magnet synchronous motor is as follows:
the electromagnetic power expression of the permanent magnet synchronous motor is as follows:
assuming that the permanent magnet remanence is below the nominal value, the no-load back emf is according to equation (1)E 0 When the power angle is reduced, the power angle theta is increased due to the reduction of the no-load counter electromotive force through the formula (4), and then the direct-axis current is increased along with the increase of the power angle according to the formula (3)I d Reduced, but cross-axis currentI q The increase, because the quadrature axis current amplitude is much greater than the direct axis current, the stator current increases, and copper loss and stray loss also increase at this time, while iron loss decreases, but total loss increases, and therefore efficiency decreases.
2. And (5) compensating the permanent magnet excitation performance difference.
When the no-load back electromotive force test value of the permanent magnet synchronous motor is different from the design value, the difference of the permanent magnet excitation performance is indicated, and the difference of the permanent magnet excitation performance influences the performance of the permanent magnet synchronous motor, so that the difference of the permanent magnet excitation performance needs to be compensated.
The method is based on the principle that the performance of the permanent magnet motor is determined by the induced electromotive force of the permanent magnet motor, and the induced electromotive force of the permanent magnet excitation performance difference motor is ensured to be consistent with a design value by adjusting electromagnetic design parameters which are convenient to change, so that the effective compensation of the permanent magnet excitation performance difference is realized.
When the no-load counter electromotive force test value measured in the step 1 is lower than the design value, the actual remanence of the permanent magnet is lower than the nominal valueB r . To compensate for the lower magnetic properties, the motor operation performance is improved by increasing the electrical load of the motor, i.e. increasing the number of turns in series for each phase winding of the motor, while reducing the paintThe wrap wire diameter enables the actual no-load counter electromotive force of the motor to be as close to a design value as possible under the condition of ensuring that the full rate of the motor slot is unchanged. When the no-load counter electromotive force test value of the motor is higher than the design value, the number of turns of each phase winding of the motor in series connection should be reduced, and meanwhile, the wire diameter of the enameled wire is increased, so that the compensated no-load counter electromotive force is ensured to be close to the design value.
The compensation principle is shown in figure 2, assuming that the residual magnetic density of the permanent magnet is lower than the rated nominal value, the no-load counter electromotive force value is lower than the design value, increasing the number of turns of the winding to enable the no-load counter electromotive force value to be close to the design value, and reducing the wire diameter to ensure that the slot filling rate is unchanged, so that the excitation performance difference is compensated. Assuming that the compensated no-load counter electromotive force is consistent with the design value, the stator resistance is increased and the copper loss is slightly increased due to the reduction of the wire diameter, but the stator current is reduced, the quadrature axis and direct axis reactance are correspondingly increased due to the increase of the number of turns, the power angle is increased, and the power factor is increased.
3. Determination of synthetic products
And (3) according to the no-load counter electromotive force of the motor after the compensation in the step (2), if the absolute test value-design value/design value is less than 2%, confirming that the motor is a qualified product and permitting the motor to be sold in a factory.
Step 2 is that the change value delta of the number of turns in series connection of each phaseNThe value principle is that the back electromotive force of the no-load after compensation approaches the design value according to the formula (1), namelyE 0 (N+ or- (II-) vigilanceN) About equal toE 0 (design) in the formulaE 0 For the no-load back emf,Nfor each phase winding series turnsNThe number of turns varies for each phase in series.
The value-taking principle of the change value of the wire diameter of the enameled wire in the step 2.1 and the step 2.2 is that the groove filling rate in the formula (2) is satisfiedS f Is unchanged.
Fig. 4 is a data diagram of the implementation compensation result of a 1.5kW permanent magnet synchronous motor based on a method for compensating the permanent magnet excitation performance difference in the mass production of the permanent magnet motor. The compensation method for the permanent magnet excitation performance difference in the mass production of the permanent magnet motor can improve the motor performance reduction caused by the permanent magnet excitation performance difference.
The permanent magnet synchronous motor in the above embodiment is a 1.5kW three-phase motor, but is also generalized to be suitable for multi-phase multipole situations of other power classes, including permanent magnet generators.
It should be understood that the foregoing detailed description of the present invention is provided for illustration only and is not limited to the technical solutions described in the embodiments of the present invention, and those skilled in the art should understand that the present invention may be modified or substituted for the same technical effects; as long as the use requirement is met, the invention is within the protection scope of the invention.
Claims (1)
1. A compensation method for the permanent magnet excitation performance difference in the mass production of permanent magnet motors is characterized by comprising the following steps:
step 1, determining the basic principle of the operation performance of a permanent magnet synchronous motor according to induced electromotive force, and judging the difference of permanent magnet excitation performance;
the relation between the induced electromotive force and the residual magnetic density of the permanent magnet synchronous motor is as follows:
wherein E is 0 The unit is V, which is no-load back electromotive force; f is the rated operating frequency in Hz; k (K) dp Is the winding coefficient; n is the number of turns of each phase winding in series; k (K) Φ Is the wave form factor of the air gap magnetic field; b m0 The permanent magnet no-load working point; b (B) r The residual magnetic density is given by T; a is that m The unit is cm for the cross section area of each pole of magnetic flux 2 ；σ 0 Is no-load leakage magnetic coefficient;
the difference of the residual magnetic density, namely the difference of the permanent magnet excitation performance, can be reflected by measuring the no-load counter electromotive force of the permanent magnet synchronous motor;
step 2, compensating the permanent magnet excitation performance difference to determine a qualified product;
in the step 2, the difference compensation of the permanent magnet excitation performance is realized by adjusting the number of turns and the wire diameter of each phase of the motor winding in series, and the actual no-load counter electromotive force is close to a design value under the condition that the slot full rate does not exceed a limit value;
in the step 2, when the no-load counter electromotive force test value of the motor is lower than the design value, the actual residual magnetic density of the permanent magnet is lower than the nominal value; in order to compensate the magnetic performance which is too low, the motor operability is improved, and the electric load of the motor needs to be increased, namely the number of turns of each phase of winding of the motor in series is increased; in order to ensure that the groove filling rate is unchanged compared with the original design, the wire diameter of the enameled wire should be reduced while the number of turns is increased;
when the no-load counter electromotive force test value of the motor is higher than the design value, the number of turns of each phase winding of the motor in series connection is reduced, and meanwhile, the wire diameter of the enameled wire is increased, so that the actual no-load counter electromotive force is ensured to be as close to the design value as possible;
the principle of the change value delta N of the number of turns in each phase is that the back electromotive force of the no-load after compensation approaches to the design value, namely E 0(N+△N) ≈E 0 (design) In which E 0 The counter electromotive force is no-load counter electromotive force, N is the number of turns of each phase winding in series, and delta N is the change value of the number of turns of each phase in series;
the principle of the change value delta d of the wire diameter of the enameled wire is that the full rate S of the medium groove is satisfied f Unchanged;
in N i To wind the root number in parallel, N s Delta N for number of conductors per slot s D is the wire diameter and A is the variation value of the number of conductors in each slot ef Is the effective area of the groove;
in the step 1, the determination of the permanent magnet excitation performance difference of the permanent magnet synchronous motor is realized by measuring the no-load counter electromotive force of the motor, wherein the no-load counter electromotive force is obtained by a reverse dragging method or a minimum current method, and if the absolute test value-design value absolute/design value is more than 5%, the permanent magnet excitation performance difference is shown;
the principle of judging the permanent magnet excitation performance and the motor performance through no-load back electromotive force is as follows:
the expression of the alternating current and the direct current of the permanent magnet synchronous motor is as follows:
in which I d Is a direct axis current, I q Is the quadrature axis current, U is the effective value of phase voltage, theta is the power angle of the motor, X d Is the direct axis synchronous reactance, X q The reactance is synchronous to the quadrature axis;
the electromagnetic power expression of the permanent magnet synchronous motor is as follows:
wherein m is the number of motor phases, E 0 Is no-load back electromotive force, U is effective value of phase voltage, theta is power angle of motor, X d Is the direct axis synchronous reactance, X q The reactance is synchronous to the quadrature axis;
assuming that the permanent magnet remanence is below the nominal value, the no-load back emf E is according to equation (1) 0 When the power angle is reduced, the power angle theta is increased due to the reduction of no-load counter electromotive force through the formula (4), and then the direct-axis current I is increased along with the increase of the power angle according to the formula (3) d Reduced, and the quadrature axis current I q The increase, because the quadrature axis current amplitude is far greater than the direct axis current, the stator current increases, the copper loss and stray loss also increase at this time, although the ironThe consumption is reduced, but the total loss is increased, and therefore the efficiency is reduced;
the reverse dragging method is to drag a tested motor by a prime motor, do no-load operation of a generator at synchronous rotation speed, measure three line voltages at the output end of the tested motor, and take the average value as no-load counter electromotive force; the prime motor is a three-phase synchronous motor with the same pole number and the same power or a three-phase asynchronous motor with the same pole number and the same frequency, and the frequency of the three-phase asynchronous motor is adjusted to achieve the synchronous rotating speed of the three-phase permanent magnet synchronous motor during test; or selecting synchronous machines or asynchronous machines with different poles and different frequencies, wherein the synchronous rotating speed of the tested machine is ensured to be reached;
the minimum current method is that the tested machine runs in no-load under the rated voltage and rated frequency until the mechanical energy consumption is stable, and the external voltage is regulated to minimize the no-load current; the average value of the voltage of the external terminal is the no-load counter electromotive force of the permanent magnet synchronous motor;
and (3) after compensation, if the dead load back electromotive force of the motor is smaller than 2% in the absolute test value-design value, confirming that the motor is a qualified product.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102439823A (en) * | 2009-01-14 | 2012-05-02 | 罗伯特·博世有限公司 | Remanence tolerance compensation for electric machine |
| CN104184293A (en) * | 2014-07-16 | 2014-12-03 | 赵晓东 | Adjusting-type pole-changing speed-changing permanent-magnet synchronous motor |
| CN104734389A (en) * | 2013-12-20 | 2015-06-24 | 湖北海山科技有限公司上海分公司 | Stator disk and axial flux permanent magnet kinetic energy device |
| CN105717451A (en) * | 2016-01-22 | 2016-06-29 | 刘玉臻 | Pumping unit and method and device for measuring no-load counter electromotive force of permanent magnet motor of pumping unit |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102439823A (en) * | 2009-01-14 | 2012-05-02 | 罗伯特·博世有限公司 | Remanence tolerance compensation for electric machine |
| CN104734389A (en) * | 2013-12-20 | 2015-06-24 | 湖北海山科技有限公司上海分公司 | Stator disk and axial flux permanent magnet kinetic energy device |
| CN104184293A (en) * | 2014-07-16 | 2014-12-03 | 赵晓东 | Adjusting-type pole-changing speed-changing permanent-magnet synchronous motor |
| CN105717451A (en) * | 2016-01-22 | 2016-06-29 | 刘玉臻 | Pumping unit and method and device for measuring no-load counter electromotive force of permanent magnet motor of pumping unit |
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