CN117526660A - Brushless excitation synchronous motor with high starting torque - Google Patents
Brushless excitation synchronous motor with high starting torque Download PDFInfo
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- CN117526660A CN117526660A CN202210896992.5A CN202210896992A CN117526660A CN 117526660 A CN117526660 A CN 117526660A CN 202210896992 A CN202210896992 A CN 202210896992A CN 117526660 A CN117526660 A CN 117526660A
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- 230000005284 excitation Effects 0.000 title claims abstract description 115
- 230000001360 synchronised effect Effects 0.000 title claims abstract description 106
- 238000004804 winding Methods 0.000 claims abstract description 231
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract 4
- 238000012546 transfer Methods 0.000 claims description 17
- 238000010079 rubber tapping Methods 0.000 claims description 10
- 230000003111 delayed effect Effects 0.000 claims description 6
- 238000000034 method Methods 0.000 claims description 6
- 230000008569 process Effects 0.000 claims description 5
- 230000009467 reduction Effects 0.000 claims description 4
- 230000001419 dependent effect Effects 0.000 claims description 2
- 230000007704 transition Effects 0.000 claims description 2
- 238000013459 approach Methods 0.000 claims 1
- 238000004134 energy conservation Methods 0.000 abstract 1
- 230000001276 controlling effect Effects 0.000 description 6
- 239000003990 capacitor Substances 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000008859 change Effects 0.000 description 1
- 239000003245 coal Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000002360 explosive Substances 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K19/00—Synchronous motors or generators
- H02K19/02—Synchronous motors
- H02K19/10—Synchronous motors for multi-phase current
- H02K19/12—Synchronous motors for multi-phase current characterised by the arrangement of exciting windings, e.g. for self-excitation, compounding or pole-changing
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K1/00—Details of the magnetic circuit
- H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
- H02K1/22—Rotating parts of the magnetic circuit
- H02K1/24—Rotor cores with salient poles ; Variable reluctance rotors
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K3/00—Details of windings
- H02K3/04—Windings characterised by the conductor shape, form or construction, e.g. with bar conductors
- H02K3/18—Windings for salient poles
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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
- H02P1/00—Arrangements for starting electric motors or dynamo-electric converters
- H02P1/16—Arrangements for starting electric motors or dynamo-electric converters for starting dynamo-electric motors or dynamo-electric converters
- H02P1/46—Arrangements for starting electric motors or dynamo-electric converters for starting dynamo-electric motors or dynamo-electric converters for starting an individual synchronous motor
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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
- H02P27/00—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage
- H02P27/04—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage
- H02P27/06—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using DC to AC converters or inverters
- H02P27/08—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using DC to AC converters or inverters with pulse width modulation
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- Power Engineering (AREA)
- Synchronous Machinery (AREA)
Abstract
The invention relates to a brushless excitation synchronous motor with high starting torque, which comprises a power supply, a stator iron core, a stator power winding, a stator excitation winding, a salient pole rotor iron core, a concentric rotor winding, a power winding controller, an excitation power supply converter and an excitation winding controller, wherein the power supply provides alternating current for the stator power winding through the power winding controller, and the power supply provides controllable excitation current for the stator excitation winding through the excitation power supply converter and the excitation winding controller. The brushless excitation synchronous motor with high starting torque has simple structure, high efficiency and energy conservation, and is particularly suitable for driving load machinery requiring high starting torque.
Description
Technical Field
The present invention relates to an electrically excited synchronous motor, and more particularly to a brushless excited synchronous motor having high starting torque.
Background
The electro-excitation synchronous motor has the advantages of strong overload capacity, high power factor, stable rotating speed and the like, and is widely applied to the fields of compressors, fans, water pumps, rolling mills, ball mills and the like. The exciting winding of the traditional electric excitation synchronous motor is arranged on the rotor, exciting current is required to be provided through a slip ring and an electric brush, and due to sliding contact, the synchronous motor not only needs to be maintained regularly, but also is easy to generate sparks, and the synchronous motor is limited to be applied to flammable and explosive places such as coal mines, petroleum, chemical industry and the like.
Brushless excitation of an electrically excited synchronous motor is an important development direction, and the main mode of brushless excitation of the synchronous motor is that a three-phase alternating current generator with a rotary armature is added on a motor rotor, generated alternating current is converted into direct current through a rectifier rotating together with the motor rotor, power is supplied to an excitation winding on the rotor, the excitation winding of the excitation generator is placed on a stator, and the armature voltage of the excitation generator is regulated through a controllable rectifier, so that excitation control of the synchronous motor is realized. Although the brushless excitation mode cancels the slip ring brush, an alternating current excitation generator and a rotary rectifier are needed to be added, the structure is complex, the manufacturing cost is high, and the exciting winding current of the synchronous motor needs to be subjected to two-stage control, so that the dynamic control performance is poor.
In recent years, a brushless excitation synchronous motor with modulated magnetic field is converted from a brushless double-fed motor, an excitation winding on a rotor of a traditional electric excitation synchronous motor is moved to a stator, two sets of windings with different pole numbers are adopted on the stator and are respectively used as a power winding and an excitation winding, and a slip ring brush is not needed for the rotor winding. The brushless excitation synchronous motor has the advantages of simple structure, low cost and the like, but has the defects that the brushless synchronous motor is difficult to obtain larger starting torque due to different motor operation mechanisms, is relatively suitable for driving fan and pump loads with smaller starting torque requirements, and is difficult to be used for driving load machines such as pumping units, ball mills and the like with larger starting torque requirements.
Disclosure of Invention
In view of the drawbacks of the current brushless excitation synchronous motors, an object of the present invention is to provide a brushless excitation synchronous motor with high starting torque.
In order to achieve the purpose of the invention, the technical scheme adopted by the invention is as follows:
a brushless excitation synchronous motor with high starting torque comprises a power supply, a stator core, a stator power winding, a stator excitation winding, a salient pole rotor core, a concentric rotor winding, a rotating shaft, a stator power winding controller, an excitation power converter and a stator excitation winding controller,
wherein the stator power winding and the stator exciting winding are positioned on the stator core,
the concentric rotor windings are positioned in slots of salient pole rotor cores, which are fixed on the rotating shaft,
the power supply provides alternating current for the stator power winding through the stator power winding controller, and the power supply provides controllable excitation power for the excitation winding through the excitation power supply converter and the stator excitation winding controller.
Preferably, the sum of the number of poles of the stator power winding and the number of poles of the exciting winding is equal to the number of poles of the synchronous motor, and the difference between the number of poles of the stator exciting winding and the number of poles of the stator power winding is not less than 4.
Preferably, the salient pole rotor core has a plurality of salient poles, the number of salient poles being one half of the sum of the poles of the stator power winding and the field winding.
Preferably, a large slot is provided between every two salient poles, and a plurality of small slots having different widths and depths are provided on each salient pole, wherein the large slot and the small slot are both radial, and their center lines intersect with the center of the rotor shaft in the radial direction.
Preferably, the small slots located at the center line of the salient poles have the greatest depth and width, and the other small slots are symmetrically distributed at both sides of the small slots at the center line, and the depth and width gradually decrease.
Preferably, the concentric rotor winding is composed of a plurality of concentric coils shorted to each other, each of the concentric coils includes a plurality of multi-turn coils, both sides of each of the multi-turn coils are respectively placed or wound in different small slots with a center line of the large slot as a symmetry axis, wherein two multi-turn coils from adjacent concentric coils are placed or wound in the small slots located at the center line of the salient pole, and only one multi-turn coil is placed or wound in the small slot located at the non-center line.
Preferably, the stator power winding controller has two circuit switches K1 and K2 for switching the stator winding connection during motor start-up and normal operation.
Preferably, one ends of three-phase windings of the stator power winding are short-circuited together, and the outlet ends of the three-phase windings are connected to a power supply through a circuit switch K1 of the stator winding controller, a tapping tap is arranged in the middle of each phase winding of the stator power winding, and the outlet ends and the tapping taps of each phase winding are correspondingly connected to two ends of a circuit switch K2 in the stator power winding controller. When the motor starts, the circuit switch K1 is closed firstly, the power supply voltage is applied to all windings of the stator power winding, the winding current is relatively small, then the switch K2 is closed in a delayed mode, at the moment, the winding part between the wire outlet end of the stator power winding and the tapping tap is short-circuited, the voltage of the power supply is applied to the rest winding with the short-circuited part removed, and larger current is generated in the stator power winding due to the reduction of impedance, so that the synchronous motor has larger starting torque. The delay closed switch K2 is used to reduce the current surge of the motor windings when the power is turned on. After the synchronous motor starting process is completed and the synchronous rotating speed operation is carried out, the switch K2 is opened, and the voltage of the power supply is applied to all windings of the stator power windings, so that the current in the stator power windings is reduced, and the synchronous motor has the torque required by the load. The position of the tap in each phase winding of the stator power winding is dependent on the demand for motor starting torque.
Preferably, the stator field winding controller includes circuit change-over switches K3, K4, K5 and K6, and three-phase resistors 11 and 12. The switch K3 is used for controlling exciting current of the stator exciting winding, the switch K4 is used for controlling series resistance of the stator exciting winding, and the switches K5 and K6 are used for controlling switching of the series resistances 11 and 12 of the exciting winding.
Preferably, during the asynchronous starting, the synchronous pulling and the synchronous speed running state transition of the synchronous motor, the following constraint relationship exists between the circuit transfer switches K1 and K2 of the stator power winding controller and the circuit transfer switches K3, K4, K5 and K6 of the stator exciting winding controller: when the synchronous motor starts, firstly, K3, K5 and K6 are disconnected, K4 and K1 are closed, K2 is closed in a delayed mode, at the moment, the synchronous motor is in an asynchronous starting state, a stator exciting winding is connected in series with three-phase resistors 11 and 12 to increase starting torque, the current frequency and amplitude of the stator exciting winding are reduced along with the increase of the rotating speed of the motor, in order to keep the required starting torque, firstly, a switch K5 is closed, a series resistor 11 is cut off, after the rotating speed of the motor is further increased, a switch K6 is closed, a series resistor 12 is cut off, at the moment, the exciting winding is in a short circuit state, when the rotating speed of the motor is close to the synchronous rotating speed, the switch K3 is closed to cut off K4, the exciting winding is powered by an exciting converter instead, the motor is involved in the synchronous rotating speed operation, and after the synchronous rotating speed of the motor is stably operated, the circuit change switch K2 in a stator power winding controller is cut off, and the synchronous motor enters a normal operation state. For a synchronous motor which does not need speed regulation operation, a controllable direct current excitation power supply is provided for a stator excitation winding by an excitation power supply converter; for synchronous motors which need to operate in a speed-regulating way, a controllable alternating-current excitation power supply is provided for a stator excitation winding by an excitation power supply converter.
Compared with the prior art, the invention achieves the following remarkable technical effects:
1. the exciting winding of the conventional electric excitation synchronous motor arranged on the rotor is transferred to the stator, and power supply through a slip ring and an electric brush is not needed, so that brushless excitation is realized, the running reliability of the motor is improved, and the maintenance cost is reduced.
2. The self-short-circuit concentric winding on the rotor does not need power supply, and has simple structure, low cost and reliable operation. The motor can meet the requirements of motor starting and load running without additionally adding a starting winding, and has rapid excitation control dynamic performance.
3. When the motor starts, the starting torque of the motor is improved by changing the wiring mode of the stator power winding and the series resistance of the exciting winding, and the motor is recovered to be normally wired after being involved in synchronization, so that the requirements on the starting and load operation characteristics of the motor are met.
4. Different excitation requirements of synchronous motors with no speed regulation and speed regulation are met. For a synchronous motor which does not need speed regulation operation, a controllable direct current excitation power supply is provided for an excitation winding; for synchronous motors which need to operate at a speed, a controllable alternating-current excitation power supply is provided for the excitation winding, and only a low-cost low-power frequency converter is needed.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, a brief description of the embodiments will be provided below, and it is apparent that the drawings described below are only some embodiments of the present invention, and that other drawings can be obtained according to these drawings by a person of ordinary skill in the art without any inventive effort.
Fig. 1 schematically shows the main structure of a brushless excitation synchronous motor with high starting torque according to an embodiment of the present invention.
Fig. 2 schematically illustrates one embodiment of the end face structure of the brushless excitation synchronous motor of fig. 1 having open slot salient pole rotor cores and concentric rotor windings placed in the slots thereof.
Fig. 3 schematically illustrates another embodiment of the brushless excitation synchronous motor of fig. 1 having an end face structure of a half open slot salient pole rotor core and concentric rotor windings placed in slots thereof.
Fig. 4 schematically illustrates a structure of a stator power winding controller of the brushless excitation synchronous motor shown in fig. 1, employing a tapped stator power winding wire conversion scheme.
Fig. 5 schematically illustrates another configuration of a stator power winding controller of the brushless excitation synchronous motor shown in fig. 1, employing a wiring scheme for Y/delta conversion of the stator power winding.
Fig. 6 schematically shows the structure of a controllable rectifier of the excitation power converter of the brushless excitation synchronous motor shown in fig. 1, suitable for a controllable dc excitation power supply of a synchronous motor that does not require speed regulation.
Fig. 7 schematically shows the structure of an ac-dc-ac converter of the field power converter of the brushless field synchronous motor of fig. 1, suitable for a controllable ac field power source of a synchronous motor requiring speed regulation.
Detailed Description
In order to make the technical means, the creation features, the achievement of the purpose and the effect of the present invention easy to understand, the present invention is further described below with reference to the accompanying drawings.
Fig. 1 shows a structure of an 8-pole high starting torque brushless excitation synchronous motor. In the embodiment shown in the figure, there are included a power supply 1, a stator core 2, a stator power winding 3 and an excitation winding 4 in the stator core 2, a salient pole rotor core 5, a concentric rotor winding 6 (see fig. 2 or 3) in the salient pole rotor core 5, a rotating shaft 7 for mounting the salient pole rotor core 5, a stator winding controller 8 (see fig. 4 or 5), an excitation power converter 9 (see fig. 6 or 7), circuit switching switches K3, K4, K5 and K6 mounted in the excitation winding controller 10, and current limiting resistors 10 and 11.
The embodiment is an 8-pole brushless excitation synchronous motor, which is provided with a 2-pole three-phase stator power winding and a 6-pole three-phase excitation winding, wherein two outgoing lines of each phase winding of the power winding 3 are connected to circuit transfer switches K1 and K2 in a stator winding controller 8; the exciting winding 4 adopts a Y-shaped wiring mode, and the outlet ends of the three-phase winding are connected to circuit transfer switches K3 and K4 in the exciting winding controller 10.
The circuits of the stator power winding 3 and the exciting winding 4 are mutually independent, the power supply 1 supplies alternating current to the stator power winding 3 through the stator power winding controller 8, and the power supply 1 supplies controllable exciting power to the exciting winding 4 through the exciting power supply converter 9 and the stator exciting winding controller 10.
The stator field winding controller 10 includes circuit transfer switches K3, K4, K5, and K6, and three-phase resistors 11 and 12. The switch K3 is used for controlling exciting current of the stator exciting winding 4, the switch K4 is used for controlling series resistance of the stator exciting winding 4, and the switches K5 and K6 are used for controlling switching of the exciting winding series resistances 11 and 12.
Fig. 2 shows an embodiment of the end face structure of the salient pole rotor core of the high starting torque brushless excitation synchronous motor of the present invention and the concentric rotor windings placed thereon. In this embodiment, the number of poles of the synchronous motor is 8, and the number of salient poles of the salient pole rotor core 5 is 4. A large groove 51 is arranged between every two salient poles, 5 full-open small grooves with different widths and depths (the notch and the groove bottom of each small groove are of equal width) are arranged on each salient pole, and 511, 512, 513, 514 and 515 are arranged radially from left to right. The third small slot 513 is located at the center line of the salient pole and has the greatest depth and width, the second small slot 512 and the fourth small slot 514 are symmetrically distributed at both sides of the third small slot 512, and their depths and widths are the same and smaller than those of the third small slot 513, and the first small slot 511 and the fifth small slot 515 are symmetrically distributed at the left side of the second small slot 512 and the right side of the fourth small slot 514, respectively, and their depths and widths are the same and smaller than those of the second small slot 512 and the fourth small slot 514.
The concentric rotor winding 6 is made up of a plurality of concentric coils shorted to each other, each including 3 multi-turn coils, a first multi-turn coil 61, a second multi-turn coil 62 and a third multi-turn coil 63. The two sides of the multi-turn coil 61 are placed in the first small groove 511 on one salient pole and the fifth small groove 515 on the left adjacent salient pole, respectively, with the center line of the large groove 51 as a symmetry axis, the two sides of the second multi-turn coil 62 are placed in the second small groove 512 on one salient pole and the fourth small groove 514 on the left adjacent salient pole, respectively, and the two sides of the third multi-turn coil 63 are placed on the left of the third small groove 513 of one salient pole and the right of the third small groove 513 on the left adjacent salient pole, respectively. The third slot 513 on each land is placed with the third multi-turn coil 63 side of two adjacent concentric coils and only one multi-turn coil 61 or 62 side is placed in the slot at the non-center line. The salient pole rotor core structure adopting the full open slot is convenient for the rotor to adopt the coil inserting technology of the hard winding forming coil.
Fig. 3 shows another embodiment of the end face structure of a salient pole rotor core of a brushless excitation synchronous motor with high starting torque and concentric rotor windings placed thereon of the present invention. In this embodiment, the number of poles of the synchronous motor is 8, and the number of salient poles of the salient pole rotor core 5 is 4. A large groove 51 is arranged between every two salient poles, 5 semi-open small grooves with different widths and depths (each small groove is not equal in width and is smaller in width at a notch part) are arranged on each salient pole, and 511, 512, 513, 514 and 515 are arranged radially from left to right. The third small slot 513 is located at the center line of the salient pole and has the greatest depth and width, the second small slot 512 and the fourth small slot 514 are symmetrically distributed at both sides of the third small slot 512, and their depths and widths are the same and smaller than those of the third small slot 513, and the first small slot 511 and the fifth small slot 515 are symmetrically distributed at the left side of the second small slot 512 and the right side of the fourth small slot 514, respectively, and their depths and widths are the same and smaller than those of the second small slot 512 and the fourth small slot 514.
The concentric rotor winding 6 is made up of a plurality of concentric coils shorted to each other, each including 3 multi-turn coils, a first multi-turn coil 61, a second multi-turn coil 62 and a third multi-turn coil 63. The two sides of the multi-turn coil 61 are respectively placed in the first small groove 511 on one convex pole and the fifth small groove 515 on the left adjacent convex pole with the center line of the large groove 51 as a symmetry axis, the two sides of the second multi-turn coil 62 are respectively placed in the second small groove 512 on one convex pole and the fourth small groove 514 on the left adjacent convex pole, and the two sides of the third multi-turn coil 63 are respectively placed in the upper part close to the notch in the third small groove 513 of one convex pole and the lower part close to the groove bottom in the third small groove 513 on the left adjacent convex pole. The third slot 513 on each land is placed with the third multi-turn coil 63 side of two adjacent concentric coils and only one multi-turn coil 61 or 62 side is placed in the slot at the non-center line. The salient pole rotor core structure adopting the half open slot is convenient for the coil inserting process of the multi-turn soft winding concentric coil which is formed by parallelly winding a plurality of thin wires on the rotor.
The number of multi-turn coils of concentric coils per salient pole of the salient pole rotor core shown in fig. 2 and 3 is related to the number of poles of the motor, and for 8 and 12-pole motors, the number of poles is small, the salient poles are relatively wide, 5-7 slots can be provided on the salient poles, 3-4 multi-turn coils can be wound on each salient pole, and for more-pole motors, the number of slots can be provided on the salient poles is relatively narrow, the number of multi-turn coils can be reduced on each salient pole, but at least one multi-turn coil is required to be positioned in a slot at the center line of the salient pole.
Fig. 4 schematically shows a structure of the stator power winding controller 8 of the brushless excitation synchronous motor shown in fig. 1, which adopts a wire switching method of the stator power winding 3 with a tap. One end of the three-phase winding of the stator power winding 3 is short-circuited together, the outlet end of the three-phase winding is connected to the power supply 1 through the circuit switch K1 of the stator power winding controller 8, a tapping tap is arranged in the middle of each phase winding of the stator power winding 3, and the outlet end and the tapping tap of each phase winding are correspondingly connected to two ends of the circuit switch K2 in the stator power winding controller 8. When the motor starts, the circuit switch K1 is firstly closed, the power supply voltage is applied to all windings of the stator power winding 3, the winding current is relatively small, then the switch K2 is closed in a delayed mode, at the moment, the winding part between the wire outlet end of the stator power winding 3 and the tapping tap is short-circuited, the voltage of the power supply 1 is applied to the stator power winding 3 with the rest short-circuited part removed, and larger current is generated in the stator power winding 3 due to the reduction of impedance, so that the synchronous motor has larger starting torque. The time delay closing switch K2 is used to reduce the current surge of the stator power winding 3 when the power is turned on. After the synchronous motor starting process is completed and the synchronous rotating speed operation is carried out, the switch K2 is opened, the voltage of the power supply 1 is applied to all windings of the stator power winding 3, and the current in the stator power winding 3 is reduced, so that the synchronous motor has the torque required by the load. The position of the tapping point of the stator power winding 3 can be set according to the requirements for the starting current and the torque of the motor, and the wiring conversion mode of the stator power winding 3 is particularly suitable for the application occasions with specific requirements for the starting current and the torque of the motor.
Fig. 5 schematically shows another configuration of the stator power winding controller 8 of the brushless excitation synchronous motor shown in fig. 1, in which the stator power winding 3 is wired by Y/delta conversion. When the motor starts, the switch K2 is in an on-state, the switch K1 is in an off-state, the stator power winding 3 is in a delta-shaped wiring mode, the line voltage of the power supply 1 is applied to the phase windings of the stator power winding 3, and a large current is generated in the stator power winding 3, so that the synchronous motor has a large starting torque. After the synchronous motor starts, the switch K2 is turned to be in a closed state and the switch K1 is turned to be in an open state, at this time, the stator power winding 3 is in a Y-type wiring mode, the phase voltage of the power supply 1 is added to the phase winding of the stator power winding 3, and the current in the stator power winding 3 is reduced, so that the synchronous motor has the torque required by the load. The Y/delta connection switching mode of the stator power winding 3 does not need winding tapping, simplifies the winding manufacturing process, and is suitable for application occasions without specific requirements on starting current and torque of the motor.
Fig. 6 schematically shows a construction of the excitation power supply converter 9 of the brushless excitation synchronous motor shown in fig. 1, which is suitable for synchronous motors that do not require speed regulation, a controllable direct-current excitation power supply consisting of a controllable rectifier 91 consisting of 6 thyristors and a filter capacitor C. The three-phase alternating current power supply of the controllable rectifier 91 is supplied by the power supply 1, is converted into a controllable direct current power supply after being rectified by the controllable rectifier 91 and filtered by the capacitor C, and is provided with a parallel output terminal at the negative output end of the output, so that the controllable rectifying power supply is provided with three output ends of which the positive and the negative are respectively connected to the circuit change-over switch K4 in the stator exciting winding controller 10. When the switch K4 is closed, the exciting power converter 9 will provide controllable dc exciting current for the stator exciting winding 4, and for the stator exciting winding 4 adopting the Y-shaped wiring mode, the dc exciting current flows in from one phase winding and flows out from the other two phase windings.
Fig. 7 schematically shows the structure of an ac-dc-ac converter of the field power converter 9 of the brushless field synchronous motor of fig. 1, suitable for a controllable ac field power supply of a synchronous motor requiring speed regulation. The exciting power supply converter 9 is composed of a three-phase rectifier 91, a filter capacitor C, PWM and a frequency converter 92. The three-phase rectifier 91 is supplied with three-phase alternating current power by the power supply 1, the three-phase alternating current power is converted into direct current power after being rectified by the three-phase rectifier 91 and filtered by the capacitor C, and then is converted into three-phase alternating current excitation power with adjustable frequency, amplitude and phase by the PWM (pulse width modulation) frequency converter 92, and the three-phase output end of the PWM frequency converter 92 is connected to the circuit change-over switch K4 in the stator excitation winding controller 10. When the switch K4 is closed, the excitation power converter 9 will supply the stator excitation winding 4 with a frequency, amplitude and phase adjustable three-phase ac excitation current.
Taking the winding tapping stator power winding controller shown in fig. 1 as an example, the working process of the brushless excitation synchronous motor with high starting torque of the invention is as follows:
when the synchronous motor is started, firstly, K3, K5 and K6 are disconnected, K4 and K1 are closed, K2 is closed in a delayed mode, at the moment, the synchronous motor is in an asynchronous starting state, the voltage of the power supply 1 is added to the stator power winding 3 with the rest of short-circuit parts removed, and larger current is generated in the stator power winding due to the reduction of impedance, so that the motor has larger starting torque; when K4 is closed, the stator exciting winding 4 is connected in series with three-phase resistors 11 and 12 to increase starting torque, the current frequency and amplitude of the stator exciting winding 4 are reduced along with the increase of the motor rotating speed, in order to keep the required starting torque, the switch K5 is closed firstly, the series resistor 11 is cut off, after the motor rotating speed is further increased, the switch K6 is closed, the series resistor 12 is cut off, at the moment, the stator exciting winding 4 is in a short circuit state, when the motor rotating speed is close to the synchronous rotating speed, the switch K3 is closed to cut off K4, the stator exciting winding 4 is powered by the exciting current transformer 9, the motor is pulled into the synchronous rotating speed to operate, after the motor is stably operated at the synchronous rotating speed, the circuit change-over switch K2 in the stator power winding controller 9 is cut off, the voltage of the power supply 1 is added to all the stator power windings 3, and the synchronous motor enters a normal operation state. For a synchronous motor which does not need speed regulation operation, a controllable direct current excitation power supply is provided for the stator excitation winding 4 by an excitation power supply converter 9; for synchronous motors which need to operate at a speed, a controllable alternating current excitation power supply is provided for the stator excitation winding 4 by an excitation power supply converter 9.
The foregoing has shown and described the basic principles, main features and advantages of the present invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, and that the above embodiments and descriptions are merely illustrative of the principles of the present invention, and various changes and modifications may be made without departing from the spirit and scope of the invention, which is defined in the appended claims. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (14)
1. A brushless excitation synchronous motor with high starting torque is characterized in that the synchronous motor comprises a power supply (1), a stator iron core (2), a stator power winding (3), a stator excitation winding (4), a salient pole rotor iron core (5), a concentric rotor winding (6), a rotating shaft (7), a stator power winding controller (8), an excitation power supply converter (9) and a stator excitation winding controller (10),
wherein the stator power winding (3) and the stator excitation winding (4) are located in slots of the stator core (2),
the rotor concentric rotor winding (6) is positioned in the groove of the salient pole rotor core (5), the salient pole rotor core (5) is fixed on the rotating shaft (7),
the stator power winding controller (8) comprises a circuit change-over switch K1 and a circuit change-over switch K2,
the stator exciting winding controller (10) comprises circuit transfer switches K3, K4, K5 and K6, three-phase resistors (11) and (12),
the power supply (1) provides alternating current for the stator power winding (3) through a stator power winding controller (8), and the power supply (1) provides controllable excitation power for the excitation winding (4) through an excitation power converter (9) and a stator excitation winding controller (10).
2. The high-starting-torque brushless excitation synchronous motor according to claim 1, characterized in that a sum of pole numbers of the stator power winding (3) and the stator exciting winding (4) is equal to a pole number of the synchronous motor, and a difference between the pole numbers of the stator exciting winding (4) and the stator power winding (3) is equal to or larger than 4, and a salient pole number of the salient pole rotor core (5) is one half of the sum of pole numbers of the stator power winding (3) and the stator exciting winding (4).
3. The high starting torque brushless excitation synchronous motor according to claims 1 and 2, characterized in that one end of the three-phase windings of the stator power winding (3) are shorted together, and the three-phase winding outgoing line ends are connected to a circuit change-over switch K1 in the stator power winding controller (8), and there is one tap in the middle of each phase winding of the stator power winding (3), and the outgoing line end and tap of each phase winding are connected to two ends of the circuit change-over switch K2 in the stator power winding controller (8) (as shown in fig. 1).
4. When the motor starts, the circuit transfer switch K1 is firstly closed, the voltage of the power supply (1) is applied to all windings of the stator power winding (3), the winding current is relatively small, then the switch K2 is closed in a delayed mode, at the moment, the windings between the wire outlet end and the tapping tap of the stator power winding (3) are short-circuited, the voltage of the power supply (1) is applied to the remaining windings except for the short-circuited part, and larger current is generated in the stator power winding (3) due to the reduction of impedance, so that the synchronous motor has larger starting torque.
5. The delay closed switch K2 is used to reduce the current surge of the motor windings when the power is turned on.
6. When the synchronous motor starting process is completed and the synchronous rotating speed operation is carried out, the circuit transfer switch K2 is opened, and the voltage of the power supply (1) is applied to all windings of the stator power winding (3), so that the current in the stator power winding (3) is reduced, and the synchronous motor has the torque required by a load.
7. The position of the tap in each phase winding of the stator power winding (3) is dependent on the demand for motor starting torque.
8. The high-starting-torque brushless excitation synchronous motor according to claim 1 and 2, wherein a large slot is provided between every two salient poles of the salient pole rotor core (5), a plurality of small slots with different widths and depths are provided on each salient pole for placing the concentric rotor winding (6), the concentric rotor winding (6) is composed of a plurality of self-shorted multi-turn concentric coils, each concentric coil comprises a plurality of multi-turn coils with different turns, two sides of each multi-turn coil are respectively placed or wound in different small slots with the center line of the large slot as a symmetry axis, wherein two multi-turn coils from adjacent concentric coils are placed or wound in the small slots positioned at the center line of the salient pole, and only one multi-turn coil is placed or wound in the small slots positioned at the non-center line.
9. The high-starting-torque brushless excitation synchronous motor according to claim 1, wherein for the brushless excitation synchronous motor which does not need to operate at a speed, the excitation power supply converter (9) adopts a controllable rectifier, and the function of the excitation power supply converter is to convert alternating current of the power supply (1) into direct current with adjustable voltage after rectification, and provide a controllable direct current excitation power supply for the stator excitation winding (4) through the stator excitation winding controller (10).
10. For the brushless excitation synchronous motor needing speed regulation operation, the excitation power supply converter (9) adopts an AC-DC-AC converter, and has the functions of converting the alternating current of the power supply (1) into direct current through a rectifier, converting the direct current into alternating current with adjustable amplitude, frequency and phase through an inverter, and providing a controllable AC excitation power supply for the stator excitation winding (4) through the stator excitation winding controller (10).
11. The high-starting-torque brushless excitation synchronous motor according to claims 1 and 5, characterized in that circuit transfer switches K3 and K4 of the stator excitation winding controller (10) are used for excitation power supply and series resistance control of the stator excitation winding (4), respectively, the stator excitation winding (4) being connected to the excitation power supply without series resistance when K3 is closed and K4 is open; when K3 is disconnected and K4 is closed, the stator exciting winding (4) is disconnected from the exciting power supply and connected with the series resistors (11) and (12).
12. The circuit transfer switches K5 and K6 are used for switching control of series resistors (11) and (12) of the exciting winding (4), the series resistor (11) is cut off when the switch K5 is closed, and the series resistor (12) is cut off when the switch K6 is closed.
13. The high-starting-torque brushless excitation synchronous motor according to claims 3, 4, 5 and 6, characterized in that during asynchronous starting, involvement synchronization and synchronous speed running state transition of the synchronous motor, the circuit transfer switches K1 and K2 of the stator power winding controller (8) and the circuit transfer switches K3, K4, K5 and K6 of the stator excitation winding controller (10) have the following constraint relation: when the synchronous motor starts, the circuit transfer switches K3, K5 and K6 are firstly opened, the circuit transfer switches K4 and K1 are closed, the series resistor K2 is closed in a delayed mode, at the moment, the synchronous motor is in an asynchronous starting state, the stator exciting winding (4) is connected in series with the three-phase resistors (11) and (12) to increase starting torque, the current frequency and amplitude of the stator exciting winding (4) are reduced along with the increase of the motor rotating speed, in order to keep the required starting torque, the circuit transfer switch K5 is firstly closed, the series resistor (11) is cut off, after the motor rotating speed is further increased, the circuit transfer switch K6 is closed, the series resistor (12) is cut off, at the moment, the exciting winding (4) is in a short circuit state, when the motor rotating speed approaches to the synchronous rotating speed, the circuit transfer switch K3 is closed, meanwhile, the circuit switch K4 is opened, the exciting winding (4) is powered by the exciting current transformer (9), the synchronous motor is involved in the synchronous rotating speed, after the synchronous motor is in the synchronous rotating speed, the synchronous motor is in the steady rotating speed, the power converter (8) is controlled to be in the normal state, and the synchronous motor is in the normal state.
14. For a synchronous motor which does not need speed regulation operation, the exciting power supply converter (9) provides a controllable direct current exciting power supply for the stator exciting winding (4); for synchronous motors which need to operate at a speed, the exciting power supply converter (9) provides a controllable alternating current exciting power supply for the stator exciting winding (4).
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| CN202210896992.5A CN117526660A (en) | 2022-07-28 | 2022-07-28 | Brushless excitation synchronous motor with high starting torque |
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| CN202210896992.5A CN117526660A (en) | 2022-07-28 | 2022-07-28 | Brushless excitation synchronous motor with high starting torque |
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