CN115333323A - Double-side-length stator segmented parallel power supply asynchronous linear motor driving structure and power supply method - Google Patents

Abstract

The invention discloses a drive structure and a power supply method for an asynchronous linear motor with a double-sided long stator segmented in parallel with power supply. The position of half the segment length is divided into equal length segments, the segment length is an integer multiple of a pair of pole distances, and is less than the length of the mover induction plate, and the length of the mover induction plate is an integer multiple of a pair of pole distances; bilateral After the long stator is segmented, all segmented multi-phase windings are connected to the output end of the multi-phase converter in parallel through the bus bar, and the driving force is controlled by controlling the output voltage of the multi-phase converter and the motor slip frequency. The advantages of the invention are: higher speed, larger thrust, and more stability, adopting the structure of bilateral long stator and mover induction plate, with large thrust, light weight of mover, and stable connection between the stator iron core and the aluminum plate to electromagnetic repulsion.

Description

Drive structure and power supply method of asynchronous linear motor with double-sided long stator segmented parallel power supply

technical field

The invention relates to the technical field of electromagnetic ejection with high speed, high thrust and stable operation, and in particular to a drive structure and a power supply method of an asynchronous linear motor with double-sided long stators for segmental parallel power supply.

Background technique

With the rapid development of ultra-high-power pulse technology and electronic technology, the electromagnetic ejection device began to have a major breakthrough in the 1970s. Although it is still in the stage of experimental research and preliminary application worldwide, its potential application prospects have attracted great attention. . Electromagnetic ejection is an emerging linear propulsion technology, which is suitable for high-speed, high-thrust and stable operation scenarios. Its principle is to realize the rapid movement of ejected objects through electromagnetic energy.

At present, the linear motors used to drive the electromagnetic ejection device include bilateral permanent magnet synchronous linear motors, bilateral magnetic flux switching linear motors, and bilateral asynchronous linear motors. Bilateral permanent magnet synchronous linear motors have high energy conversion efficiency, but the permanent magnets on the mover increase the weight of the moving parts, and the normal magnetic pull between the stator and the mover is very large and makes the mover run unstable. Permanent magnets still have a certain risk of demagnetization; bilateral flux switching linear motors have high efficiency and thrust density, but the mass of the mover is large, which is not conducive to obtaining high operating acceleration; the mover structure of bilateral asynchronous linear motors is simple And the weight is light, there is no normal magnetic pulling force between the mover and the stator, the mover runs stably, and the control is easy to realize.

In the bilateral asynchronous linear motor, the power supply mode of the motor winding has series power supply and parallel power supply; the series power supply is to connect each stator segment in series and then connect it to the converter power supply. There are few wires, but the disadvantage is that the output voltage of the converter is very high, and the capacity requirement is particularly large; the parallel power supply is to connect each stator segment in parallel first and then connect it to the converter power supply. The advantage is that the output voltage of the converter is low , the winding current of the stator section covered by the non-mover is small, the copper consumption is also small, and the output current of the converter is not high, but the disadvantage is that there are more parallel connections. In the application places with very short strokes, in order to reduce the cost of cables, most of the power supply in series is used, but this power supply method will greatly reduce the operating efficiency of the system; consumption, which improves the energy conversion efficiency of the system.

In bilateral asynchronous linear motors, there are many kinds of winding structure shapes, but for better fixing, most of them adopt "L" shape and fix at the end of "L". For some applications that require high thrust, the closer the mover slider and its fixed parts are to the center of gravity of the mover, the better, but there is no extra space between the "L" winding and the mover to install the slider and its fixed parts , "L" type winding structure should not be adopted.

Linear motors can be divided into two categories: synchronous linear motors and asynchronous linear motors, so the control methods are also divided into synchronous control and asynchronous control. The synchronous drive mode needs to accurately detect the real-time position of the mover, and also needs to strictly control the synchronization between the stator and the mover; while the asynchronous drive mode also needs to know the position information of the mover, but the key point of control is to ensure that the slip frequency is within a given thrust application. point, no need to control the synchronization of the fixed and movable elements.

Contents of the invention

Aiming at the defects of the prior art, the present invention provides a drive structure and a power supply method of an asynchronous linear motor with double-sided long stator segments and parallel power supply.

In order to realize above object of the invention, the technical scheme that the present invention takes is as follows:

A driving structure of an asynchronous linear motor with double-sided long stator segmented parallel power supply, including: double-sided long stators, multi-phase windings, moving element induction plates, mechanical air gaps, multi-phase converters and busbars.

The mover induction plate is set in the middle of the double-sided long stator. There is a mechanical air gap between the double-sided long stator and the mover induction plate. The multi-phase winding is composed of multiple single-phase windings, and each phase winding is wound on both sides according to the law of electricity On the long stator core, the multi-phase converter is composed of multiple single-phase converters, and each converter controls a single-phase winding;

The double-sided long-stator asynchronous linear motor is used as the linear drive mechanism for electromagnetic ejection, and the double-sided long stators are divided into equal length segments at the same position or at a position where the two sides are staggered by half of the segment length, and the segment length is a pair of asynchronous linear motors It is an integer multiple of the pole pitch, and is less than the length of the moving element induction plate. The segmented multi-phase winding where the sub-induction board is located has a small no-load current; after the double-sided long stator is segmented, all segmented multi-phase windings are connected to the output end of the multi-phase converter through the bus bar, and the multi-phase converter is controlled by controlling the multi-phase The output voltage of the inverter and the slip frequency of the motor are used to control the driving force;

The asynchronous linear motor adopts a multi-phase winding structure, which can reduce harmonic resistance and driving force pulsation, reduce the capacity of single-phase converters, increase the total driving force, and meet the requirements of stable and large thrust during linear electromagnetic ejection; each section of the same side and the same phase The stator windings are all connected in parallel through the busbar and then powered by an independent single-phase converter, which can reduce the capacity of a single power supply converter and the current of the parallel busbar; the induction plate of the asynchronous linear motor mover is made of non-magnetic aluminum plate, which has a simple structure and a low weight. Lightweight, the structural size of the asynchronous linear motor and the capacity of the converter can be reduced when the load is light; the normal force between the mover induction plate and the double-sided long stator core is the repulsion force of automatic centering, which is beneficial Stable operation of asynchronous linear motor;

The motor adopts asynchronous control, which has low requirements for position detection accuracy, and the control strategy is simple and easy to implement; this scheme can meet the requirements of ultra-high speed, large thrust, fast acceleration and stable operation of electromagnetic ejection.

Furthermore, the multi-phase winding of the asynchronous linear motor is a segmented parallel structure, the segment length is an integer multiple of a pair of pole pitches, and the minimum segment length is a pole pitch; the length of the mover induction plate is an integer multiple of a pair of pole pitches , and is far greater than the segment length of the stator, which is an integer multiple of the segment length; the smaller the segment length of the stator, the longer the mover, and the smaller the thrust fluctuation; the motor stators on both sides with longer segments are staggered by half A segmented length installation further reduces thrust fluctuations.

Furthermore, a single-phase converter with independent phases on one side is installed in the middle of the supplied long stator, and the long stator is powered in parallel and segmented through the bus bar to the left and right, so that the bus current can be reduced, thereby reducing the Cross-sectional area of the busbar: through the connection method of multi-layer bifurcation in the middle of the busbar, the current of the busbar near the long stator and the cross-sectional area of the busbar can be greatly reduced.

Furthermore, the double-sided long-stator asynchronous linear motor adopts multi-phase windings, which can reduce harmonic resistance and driving force pulsation, reduce the capacity of single-phase converters, and increase the total driving force; the multi-phase windings adopt concentric winding and fan-shaped structure installation It is beneficial to reserve a space close to the center of gravity of the mover induction plate, so that the mover slider and its fixed parts can be installed close to the center of gravity of the mover induction plate, reducing the head-up or nodding moment of the mover, thereby increasing the force of the mover. The stability of the induction plate operation.

The invention also discloses a power supply method driven by an asynchronous linear motor powered by segmented parallel connection of bilateral long stators, including:

In order to reduce the output voltage of the converter, the linear motor adopts segmented parallel power supply; the parallel mode in the dual power supply mode is that the long stators on both sides are respectively segmented in parallel and then powered by the converter power supply on each side; the parallel mode in the single power supply mode There are two types, one is that the long stator segments on both sides are connected in parallel to the bus bars on the same side, and then the bus bars on both sides are connected in parallel to be powered by the same power supply; the other is that the long stator segments on both sides at the same position are based on the principle of the same traveling wave magnetic field In series and then in parallel with stator segments at other locations, and finally powered by the same source.

Furthermore, in the double-sided long-stator asynchronous linear motor, the same symmetrical sinusoidal current is passed to the double-sided long stator, and a traveling wave magnetic field is generated between the bilateral stators, and the traveling wave magnetic field generates an induced current in the moving element induction plate, and the induced current and the traveling wave Magnetic field interaction generates electromagnetic force to push the mover to accelerate; relative to the stator on each side, the mover receives a repulsive force, and the repulsive force on both sides interacts so that the mover is always in the middle position and will not collide with the stator core; The thrust and speed of the motor can be adjusted by adjusting the output voltage and frequency of the converter. The control strategy is simple and easy to implement, without precise position detection.

Compared with the prior art, the present invention has the advantages of:

It has higher speed, greater thrust, and more stability. It adopts a double-sided long stator and mover induction plate structure, which has large thrust, light mover weight, and stable normal electromagnetic repulsion between the stator core and the aluminum plate.

Description of drawings

Fig. 1 is a three-dimensional structural schematic diagram of a segmented length of a double-sided long-stator asynchronous linear motor according to an embodiment of the present invention;

2 is a schematic diagram of a two-dimensional structure of a double-sided long-stator asynchronous linear motor according to an embodiment of the present invention;

Fig. 3 is a concentric structure diagram of a multi-phase winding of a double-sided long-stator asynchronous linear motor according to an embodiment of the present invention;

Fig. 4 is a "fan"-shaped structural diagram of a multi-phase winding of a double-sided long-stator asynchronous linear motor according to an embodiment of the present invention;

Fig. 5 is a schematic diagram of a bilateral long stator segmentation rule according to an embodiment of the present invention;

Fig. 6 is a schematic diagram of the stator winding connection mode of the double-sided long-stator asynchronous linear motor "independent parallel power supply" according to the embodiment of the present invention;

Fig. 7 is a schematic diagram of the stator winding connection mode when the double-sided long-stator asynchronous linear motor "series-parallel power supply" according to the embodiment of the present invention;

Fig. 8 is a schematic diagram of the stator winding connection mode when the double-sided long-stator asynchronous linear motor is "supplied in parallel and in series" according to the embodiment of the present invention;

Fig. 9 is a schematic diagram of the connection between the multi-phase converter and the bus bar of the bilateral long-stator asynchronous linear motor according to the embodiment of the present invention;

Fig. 10 is a diagram showing the variation of the thrust of the double-sided long-stator asynchronous linear motor with slip frequency according to the embodiment of the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and examples.

As shown in Figures 1 to 3, a double-sided long stator segmented parallel power supply asynchronous linear motor drive structure uses a double-sided long stator asynchronous linear motor as a linear drive mechanism for electromagnetic ejection.

The double-sided long-stator asynchronous linear motor mainly includes: double-sided long stator 1, mover induction plate 2, bus bar 3, multi-phase converter 4, multi-phase winding 5 and mechanical air gap 6.

The mover induction plate 2 is set in the middle of the double-sided long stator 1, but there is a distance of a mechanical air gap 6 between them. The multi-phase winding 5 is composed of multiple single-phase windings, and each phase winding is wound on the double-sided long stator according to the law of energization. On the iron core of stator 1, the multi-phase converter 4 is also composed of multiple single-phase converters, each converter controls a phase of the stator winding, and the two-sided long stator 1 is at the same position or the two sides are staggered by half The position of the segment length is divided into equal length segments. The segment length is an integer multiple of a pair of pole pitches of the linear motor, and is far less than the length of the mover induction plate 2. The length of the mover induction plate 2 is also an integer of a pair of pole pitches. times, so that the stator winding of the segment where the mover is located has a large load current, and the stator winding of the segment where the mover is not located has a small no-load current; after the long stator segment, all the stator windings of the segment are connected in parallel through the bus bar 3 Connected to the output terminal of the multi-phase converter 4, the control of the driving force is realized by controlling the output voltage of the multi-phase converter 4 and the slip frequency of the motor; the motor adopts a multi-phase winding 5, which can reduce harmonic resistance and driving force Pulsation reduces the capacity of single-phase converters, increases the total driving force, and meets the requirements of stable high-thrust during linear electromagnetic ejection; each section of stator windings on the same side and the same phase are all connected in parallel through the busbar and then powered by an independent single-phase converter, which can Reduce the capacity of a single power supply converter and the current of the parallel busbar; the mover of the linear motor adopts a non-magnetic aluminum plate, which has a simple structure and light weight, and can reduce the structure size of the linear motor and the converter when the load is light The capacity; the normal force between the mover induction plate 2 and the two-sided long stator 1 iron core is the repulsive force of automatic centering, which is conducive to the stable operation of the mover; the motor adopts asynchronous control, which has low requirements for position detection accuracy and the control strategy Simple and easy to implement; the scheme can meet the requirements of ultra-high speed, high thrust, fast acceleration and stable operation of electromagnetic ejection.

in:

In order to eliminate the normal magnetic pulling force between the stator and the mover in the asynchronous linear motor, the present invention eliminates the electromagnetic attraction force of the stator iron core to the mover aluminum plate by adopting a double-sided long stator and an iron-free aluminum mover structure, and the stator and mover There is only a repulsive force between them, and this repulsive force makes the mover stably in the middle of the bilateral stators. In the bilateral linear motor drive, the motor can be made into a long stator or a short stator. In order to save costs, the short stator structure is often selected; but in the electromagnetic ejection drive, in order to obtain greater acceleration, the mover is required The structure is simple and light in weight, so the scheme adopts the structure of double-sided long stator 1 and mover induction plate 2.

When a symmetrical alternating current is applied to the multi-phase winding 5, without considering the end effect, the mechanical air gap 6 between the two-sided stators will generate a traveling wave magnetic field distributed along the direction of motion, and the mover induction plate 2 is After the traveling wave magnetic field is cut, an induced current will be generated in the mover induction plate 2 , and the interaction between the induced current and the traveling wave magnetic field will generate electromagnetic force to push the mover to move. By controlling the stator current and slip frequency to control the thrust and speed of the motor, there is no need to detect the precise position information of the mover in real time, and precise control can also be completed at low speeds.

As shown in Figure 4, the multi-phase winding 5 is used to reduce the harmonic resistance and driving force pulsation, reduce the capacity of the single-phase converter and increase the total driving force. Generally, 9 phases, 12 phases and 15 phases can be selected; The more winding phases, the smaller the harmonic resistance, the smaller the driving force pulsation, and the more complicated the winding wiring; when the number of slots under each pole and each phase is 1, the normal wave winding and overlapping winding methods can be used; when When the number of slots under each pole and each phase is 2, in order to reduce the installation space of the winding, the concentric winding method can be used. The shape and structure of the polyphase winding 5 can also have many kinds, the common one is "L" shape, and the winding is fixed at the end of the "L" character; and the installation method adopted in this embodiment is that the shape and structure are "fan" shape, on the one hand It is to make the stator resistance of each phase equal, and on the other hand, it is to reserve a space close to the center of gravity of the mover induction plate 2, so that the mover slider and its fixing part 9 can be at a position close to the center of gravity of the mover induction plate 2 The installation reduces the head-up or nodding moment of the mover, thereby increasing the running stability of the mover induction plate 2 .

As shown in Figure 5, by segmenting the double-sided long stator 1 at the same position (Figure 5a) or at a position offset by half the segment length (Figure 5b), the segment length is much smaller than that of the mover induction plate 2 length, and the relationship between the two is an integer multiple, so that the stator of the segment where the mover is located has a large load current, while the segment where the mover is not located has a small no-load current.

Assuming that the length of the motor mover is the length of n long stator segments, when the mover moves, only n-1 stator segments 12 are fully coupled at most of the time, and only n stator segments can be fully coupled when they are completely facing the stator segment . The stator of the fully coupled section can output full power, while the output power of the stator of the incompletely coupled section is small, and the driving force received by the mover fluctuates. The more stator segments covered by the mover length, the smaller the fluctuation of the motor thrust.

As shown in Figures 6 to 9, after the long stator is segmented, all segmented stators are connected to the output end of the multi-phase converter 4 through the bus bar 3, and each phase is powered by an independent single-phase converter. There are three typical ways of parallel power supply: the first is independent parallel power supply, all segmented motor windings on one side are connected in parallel and then independently powered by a set of converters, and the long stator segments on both sides are connected in parallel to their respective busbars and then powered by their own Converter power supply; the second is series-parallel power supply, both sides are connected in series with segmented motor windings and then connected in parallel to a bus to be powered by a set of converters; the third is parallel-series power supply, all segmented motor windings on one side They are connected in parallel to their respective busbars, and then the bilateral busbars are connected in series, and finally powered by a set of converters.

The way that the multi-phase converter 4 supplies power to the long stator winding through the busbar is to install the converter in the middle of the entire long stator to be powered, and connect it to the busbar through the middle position, which can reduce the busbar current; The way of connecting the middle position of the busbar can greatly reduce the busbar current and the cross-sectional area of the busbar near the long stator, which is beneficial to the parallel connection of the segmented stator windings.

The double-sided long-stator asynchronous linear motor adopts asynchronous drive mode, and the control of the driving force is realized by controlling the output voltage of the converter and the slip frequency of the motor. The driving force of the motor first increases and then decreases with the increase of the slip frequency. The slip frequency of the working point is selected before the slip frequency corresponding to the maximum driving force, so that the drive system is self-stabilizing. When the speed of the mover slows down, The slip frequency will become larger, the driving force will increase accordingly, and the speed will also increase; on the contrary, when the moving element runs faster and approaches the synchronous speed, the slip frequency will become smaller, and the driving force will also decrease accordingly , the speed will slow down. Due to the asynchronous control, there is no need to detect the precise position of the mover in real time.

As shown in Figure 10, by calculating the equivalent circuit of the double-sided long-stator asynchronous linear motor, the magnitude of the traction force at different slip frequencies can be obtained; when the slip rate is positive, the traction force increases first with the increase of the slip frequency If we set the operating point after the slip rate corresponding to the maximum traction force, the control of the double-sided long-stator asynchronous linear motor cannot be balanced. Only by setting the operating point before the slip rate corresponding to the maximum traction force can the control be stable .

Those skilled in the art will appreciate that the embodiments described here are to help readers understand the implementation method of the present invention, and it should be understood that the protection scope of the present invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations based on the technical revelations disclosed in the present invention without departing from the essence of the present invention, and these modifications and combinations are still within the protection scope of the present invention.

Claims (6)

1. A drive structure for an asynchronous linear motor with double-sided long stator segmented parallel power supply, characterized in that it includes: double-sided long stators, multi-phase windings, moving element induction plates, mechanical air gaps, multi-phase converters and busbars; The mover induction plate is set in the middle of the double-sided long stator. There is a mechanical air gap between the double-sided long stator and the mover induction plate. The multi-phase winding is composed of multiple single-phase windings, and each phase winding is wound on both sides according to the law of electricity On the long stator core, the multi-phase converter is composed of multiple single-phase converters, and each converter controls a corresponding single-phase winding; The double-sided long-stator asynchronous linear motor is used as the linear drive mechanism for electromagnetic ejection, and the double-sided long stators are divided into equal length segments at the same position or at a position where the two sides are staggered by half of the segment length, and the segment length is a pair of asynchronous linear motors It is an integer multiple of the pole pitch, and is less than the length of the moving element induction plate. The segmented multi-phase winding where the sub-induction board is located has a small no-load current; after the double-sided long stator is segmented, all segmented multi-phase windings are connected to the output end of the multi-phase converter through the bus bar, and the multi-phase converter is controlled by controlling the multi-phase The output voltage of the inverter and the slip frequency of the motor are used to control the driving force; The asynchronous linear motor adopts a multi-phase winding structure. Each segment of the stator winding on the same side and the same phase is all connected in parallel through the bus bar and then powered by an independent single-phase converter. The asynchronous linear motor mover induction plate adopts non-magnetic aluminum plate; The normal force between the long stator cores is the repulsive force for automatic centering, which is beneficial to the stable operation of the asynchronous linear motor. 2. A drive structure for an asynchronous linear motor with double-sided long stator segmented parallel power supply according to claim 1, characterized in that: the multi-phase winding of the asynchronous linear motor is a segmented parallel structure, and the segmental length is a pair of pole pitches Integer multiples, the minimum segment length is a pole pitch; the length of the mover induction plate is an integer multiple of a pair of pole pitches, and is far greater than the segment length of the stator, which is an integer multiple of the segment length; the smaller the segment length of the stator , the longer the mover, the smaller the thrust fluctuation; the motor stators on both sides with longer segments are installed staggered by half of the segment length to further reduce the thrust fluctuation. 3. A drive structure for an asynchronous linear motor with two-sided long stator segmented parallel power supply according to claim 1, characterized in that: a single-phase converter with independent phases on one side is installed at the middle position of the long stator for power supply, through The busbar supplies power to the long stator in parallel and segmentally from the left and right; through the connection method of multi-layer bifurcation in the middle of the busbar. 4. The driving structure of a double-sided long stator segmented parallel power supply asynchronous linear motor according to claim 1, characterized in that: the double-sided long stator asynchronous linear motor adopts multi-phase winding; the multi-phase winding adopts concentric winding and fan-shaped structure installation It is beneficial to reserve a space close to the center of gravity of the mover induction plate, so that the mover slider and its fixed parts can be installed close to the center of gravity of the mover induction plate, reducing the head-up or nodding moment of the mover, thereby increasing the force of the mover. The stability of the induction plate operation. 5. A power supply method driven by an asynchronous linear motor powered by segmented parallel connection of bilateral long stators, characterized in that it comprises: In order to reduce the output voltage of the converter, the linear motor adopts segmented parallel power supply; the parallel mode in the dual power supply mode is that the long stators on both sides are respectively segmented in parallel and then powered by the converter power supply on each side; the parallel mode in the single power supply mode There are two types, one is that the long stator segments on both sides are connected in parallel to the bus bars on the same side, and then the bus bars on both sides are connected in parallel to be powered by the same power supply; the other is that the long stator segments on both sides at the same position are based on the principle of the same traveling wave magnetic field In series and then in parallel with stator segments at other locations, and finally powered by the same source. 6. The power supply method according to claim 5, characterized in that: in the double-sided long-stator asynchronous linear motor, the same symmetrical sinusoidal current is passed into the double-sided long stators, and a traveling-wave magnetic field is generated between the bilateral stators, and the traveling-wave magnetic field is in motion. The induced current is generated in the sub-induction plate, and the interaction between the induced current and the traveling wave magnetic field generates an electromagnetic force to push the mover to accelerate; relative to the stator on each side, the mover receives a repulsive force, and the repulsive force on both sides interacts to make the mover always It is in the middle position without touching the stator core; the thrust and speed of the motor can be adjusted by adjusting the output voltage and frequency of the converter, the control strategy is simple and easy to implement, and no precise position detection is required.

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