CN109599995B - Novel asynchronous multisource variable frequency motor - Google Patents
Novel asynchronous multisource variable frequency motor Download PDFInfo
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- CN109599995B CN109599995B CN201811621634.3A CN201811621634A CN109599995B CN 109599995 B CN109599995 B CN 109599995B CN 201811621634 A CN201811621634 A CN 201811621634A CN 109599995 B CN109599995 B CN 109599995B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K11/00—Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection
- H02K11/30—Structural association with control circuits or drive circuits
- H02K11/33—Drive circuits, e.g. power electronics
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Abstract
The invention provides a novel asynchronous multi-source variable frequency motor which comprises a variable frequency motor, a junction box and a frequency converter, wherein a conductor in each turn of a coil in the variable frequency motor is divided into at least two strands, each corresponding conductor is connected into an independent junction box after being connected, each junction box is electrically connected with one frequency converter, and the frequency converter is connected with a power supply. The variable frequency motor is a large-capacity motor, and the frequency converter is a small-capacity frequency converter. The number of the frequency converters is at least 2. At least one frequency converter powers the variable frequency motor. Compared with the traditional variable frequency speed control method, the method for supplying power to a plurality of frequency converters comprises the following steps: the motor and the frequency converter have the advantages of high utilization rate, high operation reliability, low requirement on the frequency converter, convenient modification, low modification cost, simple maintenance and the like.
Description
Technical Field
The invention belongs to the technical field of driving equipment, and particularly relates to a novel asynchronous multi-source variable frequency motor.
Background
With the rapid development of power electronic technology and novel semiconductor devices, the alternating current speed regulation technology is continuously improved, and the gradually improved frequency converter is widely applied to an alternating current motor with good output waveform and excellent cost performance. For example, large motors used for steel rolling in steel mills, medium and small roller bed motors, elevator motors, lifting motors for container lifting equipment, water pumps and motors for fans, compressors, motors for household appliances and the like all use AC variable frequency speed regulating motors in succession, and good effects are obtained. Compared with a direct current speed regulating motor, the alternating current variable frequency speed regulating motor has the obvious advantages of easy speed regulation, energy conservation, high-speed operation, soft start, quick braking and the like.
The rotation speed of the asynchronous motor is proportional to the frequency, and thus, the rotation speed of the asynchronous motor can be changed by changing the frequency of the power supply. In the variable frequency speed regulation, the main magnetic flux is always expected to be kept unchanged. If the main flux is larger than the flux in normal operation, the magnetic circuit is supersaturated, so that the exciting current is increased, and the power factor is reduced; if the main magnetic flux is smaller than the magnetic flux in normal operation, the torque of the motor is reduced.
However, in the conventional inverter motor control method, the motor is controlled by one inverter, and for example, the most commonly used loads such as a fan and a water pump are taken as an example, when the rotational speed of the motor is reduced to half of the rated rotational speed, the load power is reduced to 1/8 of the rated power, and the maximum power provided by the motor is close to half of the rated power, so that it can be seen that the utilization rates of the motor and the inverter are very low.
Therefore, the technical defects in the prior art are technical problems to be solved by those skilled in the art.
Disclosure of Invention
The invention mainly aims to provide a novel asynchronous multi-source variable frequency motor, and provides a novel variable frequency motor powered by two or more frequency converters aiming at the defects of the traditional variable frequency motor, compared with the traditional variable frequency speed control method, the method for powering the multiple frequency converters comprises the following steps: the motor and the frequency converter have the advantages of high utilization rate, high operation reliability, low requirement on the frequency converter, convenient modification, low modification cost, simple maintenance and the like.
In order to achieve the purpose, the invention provides a novel asynchronous multi-source variable frequency motor which comprises a variable frequency motor, a junction box and a frequency converter, wherein a conductor in each turn of a coil in the variable frequency motor is divided into at least two strands, each corresponding strand of conductor is connected into an independent junction box after being connected, each junction box is electrically connected with one frequency converter, and the frequency converters are connected with a power supply.
Further, the variable frequency motor is a large-capacity motor, and the frequency converter is a small-capacity frequency converter.
Further, the number of the frequency converters is at least 2.
Further, at least one of the frequency converters supplies power to the variable frequency motor.
By applying the technical scheme of the invention, the conductor in each turn of the coil of the variable frequency motor is divided into two or more strands, then the corresponding strand of conductor is connected into a single power supply box after being connected, and the motor is supplied with power by two or more frequency converters with the same voltage and the same phase, so that the speed regulation of one motor can be controlled by a plurality of frequency converters, the capacity of a single frequency converter is effectively reduced, the number of the power supply frequency converters can be reduced as required when the load is reduced, and the load can be properly reduced to continue to operate when the single frequency converter fails, thereby improving the reliability of system operation.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:
FIG. 1 is a schematic wiring diagram of a YKK 400-4560 kW/6kV motor in the prior art;
FIG. 2 is a wiring diagram of a modified YE 3400-4560 kW/400V motor.
Detailed Description
It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.
It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.
In this specific embodiment, fig. 1 is a schematic diagram of a connection line of a single high-capacity frequency converter controlling a high-capacity motor in the prior art, specifically, an existing YKK 400-4560 kW/6kV high-voltage motor needs energy-saving transformation, a load is a fan and a water pump, the traditional transformation mode is to change the motor directly into a variable-frequency motor, the motor is powered by the high-voltage frequency converter, the schematic diagram of the connection line of the motor is shown in fig. 1, and corresponding performance parameters of the motor at 50Hz and 25Hz are shown in table 1.
TABLE 1
| Voltage (V)) | Frequency (Hz) | Output power (kW) | Efficiency (η) |
| 6000 | 50 | 560 | 95.3％ |
| 3000 | 25 | 70 | 94.1％ |
As can be seen from table 1 above, in the conventional inverter motor control method, the motor is controlled by one inverter, and when the rotational speed of the motor is reduced to half of the rated rotational speed (i.e., the frequency is reduced to half) under the condition that the fan and the water pump are used as loads, the load power is reduced to 1/8 of the rated power, and the maximum power that can be provided by the motor is close to half of the rated power, which can be seen that the utilization rates of the motor and the inverter are very low.
In order to reduce the working voltage of the motor and improve the use efficiency of the motor and the frequency converter, the winding mode in the motor and the number of the frequency converter in the prior art are improved, and the method specifically comprises the following steps:
the invention provides a novel asynchronous multi-source variable frequency motor which comprises a variable frequency motor, junction boxes and frequency converters, wherein conductors in each turn of a coil in the variable frequency motor are divided into at least two strands, each corresponding conductor is connected into an independent junction box after being connected, each junction box is electrically connected with one frequency converter, and the frequency converters are connected with a power supply. By the setting method, the speed regulation of one motor can be controlled by a plurality of frequency converters, so that the capacity of a single frequency converter is effectively reduced. Further, the variable frequency motor is a large-capacity motor, and the frequency converter is a small-capacity frequency converter.
Further, the number of the frequency converters is at least 2. At least one of the frequency converters supplies power to the variable frequency motor. Therefore, when the system is applied, the number of the power supply frequency converters can be reduced according to needs when the load is reduced, and the load can be properly reduced to continue running when a single frequency converter fails, so that the reliability of system running is improved.
If the YKK 400-4560 kW/6kV motor is subjected to energy-saving transformation according to the technology, the motor is changed into YE 3400-4560 kW/400V, two low-voltage frequency converters are adopted to supply power to the motor, and the power of the two frequency converters is 315kW and 250kW respectively.
YE 3400-4560 kW motor basic parameters: the rated voltage is 400V, the rated frequency is 50Hz, the number of coil turns is 3, the wire gauge in each turn of conductor is 20 multiplied by phi 1.5+18 multiplied by phi 1.4, the pitch is 1-16, the number of stator slots is 72, and the number of paths is 4. The motor wiring diagram is shown in FIG. 2, and the corresponding performance parameters of the motor at 50Hz and 25Hz are shown in Table 2.
TABLE 2
| Voltage (V) | Frequency (Hz) | Output power (kW) | Efficiency (η) | Remarks for note |
| 400 | 50 | 560 | 96.2％ | Two frequency converters for power supply |
| 200 | 25 | 70 | 94.5％ | Two frequency converters for power supply |
| 200 | 25 | 70 | 94.1％ | 315kW frequency converter power supply |
| 200 | 25 | 70 | 93.9％ | 250kW frequency converter power supply |
Referring to fig. 2 and table 2, the novel asynchronous multi-source variable frequency motor connects the conductor 20 x phi 1.5 of each turn of coil separately to a separate junction box and is externally connected with a 315kW frequency converter; the conductor 18 x phi 1.4 in each turn of coil is separately connected with a separate junction box and is externally connected with a 250kW frequency converter, when the motor runs at the rotating speed of 25-40Hz, the running requirement of the motor can be met only by opening the 315kW frequency converter connected with the 20 x phi 1.5 junction box, and when the motor runs at the rotating speed of 5-25Hz, the running requirement of the motor can be met only by opening the 250kW frequency converter connected with the 18 x phi 1.4 junction box.
As shown in FIG. 2, wherein the U1 phase, U2 phase, W1 phase, W2 phase, V1 phase and V2 phase are divided into two parts;
one strand of the U1 phase and one strand of the W2 phase are connected to a first junction box, and the other strand of the U1 phase and the other strand of the W2 phase are connected to a second junction box; one strand of the V1 phase and one strand of the U2 phase are connected to a first junction box, and the other strand of the V1 phase and the other strand of the U2 phase are connected to a second junction box; one strand of the W1 phase and one strand of the V2 phase are connected to a first junction box, and the other strand of the W1 phase and the other strand of the V2 phase are connected to a second junction box; the first junction box and the second junction box are respectively and electrically connected with a frequency converter.
Aiming at motors with different models, powers and working conditions, the number of the frequency converters can be selected according to specific conditions, and different control strategies are designed.
By comparing table 1 and table 2, it can be found that when the motor operates under the rated working condition of 50Hz, the efficiency of the motor after the traditional energy-saving transformation is 95.3%, while the efficiency of the motor after the energy-saving transformation according to the technology of the invention is 96.2%. When the motor operates under the working condition of 25Hz, the efficiency of the motor is equivalent to that of the motor, but the energy-saving reconstruction can be realized only by two low-voltage small-capacity frequency converters, the cost is greatly reduced compared with the cost of a high-voltage frequency converter required by the traditional energy-saving reconstruction, and higher use efficiency can be achieved under the condition of control of a single frequency converter.
The improved novel asynchronous multi-source variable frequency speed regulating motor realizes that a plurality of small-capacity frequency converters control a single large-capacity motor, the large-capacity high-voltage motor can be replaced by a low-voltage large-capacity motor, and the large-capacity high-voltage frequency converter can be replaced by a plurality of sets of low-voltage small-capacity frequency converters. Therefore, the reliability of the frequency converter is improved, the capacity of the frequency converter is reduced, and the defects of large occupied area, complex maintenance and use and the like of the high-voltage frequency converter are overcome.
The implementation of the invention reduces the technical requirements on the frequency converter, and particularly, the high-capacity frequency converter needs special design by manufacturers and has the defects of long design period, long delivery time, high purchase cost, high maintenance cost and the like. According to the invention, the motor is reformed, a plurality of conventional small-capacity frequency converters can replace a single large-capacity frequency converter, the multi-frequency converter controls the motor, the equipment failure risk can be effectively reduced, when the frequency converter fails, other frequency converters can be started to operate at low power and low rotating speed, the equipment is prevented from being directly shut down, and the loss of a manufacturer caused by the equipment failure is effectively reduced.
In summary, the preferred embodiments of the present invention are described above, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the scope of the present invention, and equivalents and modifications of the technical solutions and concepts of the present invention should be included in the scope of the present invention.
Claims (4)
1. The utility model provides a novel asynchronous multisource variable frequency motor which characterized in that: the variable frequency motor comprises a variable frequency motor, a junction box and a frequency converter, wherein a conductor in each turn of a coil in the variable frequency motor is divided into at least two strands, wherein the U1 phase, the U2 phase, the W1 phase, the W2 phase, the V1 phase and the V2 phase are divided into two strands;
one strand of the U1 phase and one strand of the W2 phase are connected to a first junction box, and the other strand of the U1 phase and the other strand of the W2 phase are connected to a second junction box;
one strand of the V1 phase and one strand of the U2 phase are connected to a first junction box, and the other strand of the V1 phase and the other strand of the U2 phase are connected to a second junction box;
one strand of the W1 phase and one strand of the V2 phase are connected to a first junction box, and the other strand of the W1 phase and the other strand of the V2 phase are connected to a second junction box;
the first junction box and the second junction box are respectively and electrically connected with a frequency converter, and the frequency converter is connected with a power supply.
2. A novel asynchronous multi-source variable frequency motor according to claim 1, characterized in that: the variable frequency motor is a large-capacity motor, and the frequency converter is a small-capacity frequency converter.
3. A novel asynchronous multi-source variable frequency motor according to claim 2, characterized in that: the number of the frequency converters is at least 2.
4. A novel asynchronous multi-source variable frequency motor according to claim 3, characterized in that: at least one of the frequency converters supplies power to the variable frequency motor.
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| CN201811621634.3A CN109599995B (en) | 2018-12-28 | 2018-12-28 | Novel asynchronous multisource variable frequency motor |
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| CN201811621634.3A CN109599995B (en) | 2018-12-28 | 2018-12-28 | Novel asynchronous multisource variable frequency motor |
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| CN109599995B true CN109599995B (en) | 2020-09-11 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US20110050150A1 (en) * | 2008-01-18 | 2011-03-03 | Magnus Lindmark Lilliestrale | Electric motor |
| CN201726231U (en) * | 2010-07-21 | 2011-01-26 | 余成东 | Junction box and variable speed, variable frequency motor with junction box |
| CN201830192U (en) * | 2010-10-30 | 2011-05-11 | 山东泰鼎矿山机械有限公司 | Mine hoist control system driven by permanent magnet motor |
| CN102355043A (en) * | 2011-10-24 | 2012-02-15 | 北京国电四维清洁能源技术有限公司 | Multiple variable-frequency power supply combined power device with redundancy design |
| CN106655648A (en) * | 2016-11-30 | 2017-05-10 | 华中科技大学 | Modular motor system and driving control method therefor |
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