Method for controlling slip power of linear motor, maglev train, equipment and medium

Abstract

The application discloses a slip power control method of a linear motor, a maglev train, equipment and a medium, and relates to the technical field of linear motor control. The method comprises the following steps: controlling a first double-fed linear motor and a second double-fed linear motor to generate different primary power supply frequencies, and then obtaining different slip frequencies; under the premise of controlling the first double-fed linear motor and the second double-fed linear motor to generate a required composite driving force, respectively controlling a pair of balance forces with equal size and opposite directions to be superposed on the secondaries of the first double-fed linear motor and the second double-fed linear motor; and according to the slip frequencies, adjusting the size of the balance forces to adjust the slip power of the first double-fed linear motor and the second double-fed linear motor. The application can effectively control the slip power when the reaction force of the double-fed linear motor is insufficient.

Description

Slip power control method for linear motors, maglev trains, equipment and media Technical Field

[0001] This invention relates to the field of motor control technology, and in particular to a slip power control method for a linear motor, a maglev train, equipment, and medium. Background Technology

[0002] High-speed maglev train technology addresses the major national need for high-speed, high-capacity intercity transportation and has significant strategic value. Among its features, the doubly-fed linear motor quasi-synchronous operation mode integrates traction, levitation, and power supply capabilities, and offers advantages such as vehicle-track frequency coupling and dynamic decoupling of levitation and traction.

[0003] In the control of a doubly-fed linear motor, slip power is required to provide contactless power to the mover (i.e., the carriage of the maglev train). The slip power of the doubly-fed linear motor is algebraically coupled with the product of the slip frequency and the traction force, which can be expressed as:

[0004]

[0005] Where, ω f F is the slip frequency. x For traction force, τ p The sign indicates the pole pitch. The negative sign only indicates that the power supply from the DC side to the DFLM (doubly fed linear motor) mover is in the positive direction; therefore, in actual applications, the slip power is represented by a negative value.

[0006] Currently known slip power control strategies for doubly-fed linear motors all employ direct control of the slip frequency. This control method is based on the premise that the doubly-fed linear motor has a large traction force or large braking force. For example, under conditions of large traction force (F... x >0), control the slip frequency to a positive value (subsynchronous mode); under conditions of large braking force (F x <0)), control the slip frequency to a negative value (super synchronization mode).

[0007] However, when the doubly-fed linear motor is in a sub-reaction force scenario, such as the coasting mode of a maglev train (i.e., traveling at a relatively slow speed), it will not generate sufficient air resistance, thus resulting in insufficient driving force. In such cases, according to the slip power equation mentioned above, it can be seen that with a limited slip frequency, the doubly-fed linear motor cannot generate sufficient slip power; or a very high slip frequency is required, resulting in very high reactive power and extremely large inverter capacity.

[0008] In summary, current control methods are not applicable to scenarios where slip power is maintained or controlled when a doubly fed linear motor is operating under under-reaction force conditions. Summary of the Invention

[0009] The main objective of this invention is to provide a method for controlling the slip power of a linear motor, a maglev train, a device, a terminal equipment, and a computer-readable storage medium, aiming to achieve effective control of slip power when the reaction force of a doubly fed linear motor is insufficient.

[0010] To achieve the above objectives, the present invention provides a slip power control method for a linear motor. The slip power control method is applied to a linear maglev transport system. The linear maglev transport system includes a first doubly fed linear motor and a second doubly fed linear motor symmetrically arranged on the left and right sides. Both the first doubly fed linear motor and the second doubly fed linear motor include a primary and a secondary. The primary is fixedly arranged, and the secondary is installed on the same moving transport component that can perform linear motion relative to the primary.

[0011] The slip power control method includes:

[0012] By controlling the first doubly fed linear motor and the second doubly fed linear motor to generate different primary power supply frequencies, different slip frequencies can be obtained;

[0013] Under the premise of controlling the first doubly fed linear motor and the second doubly fed linear motor to generate the required combined driving force, a pair of equal and opposite balancing forces are superimposed on the secondary windings of the first doubly fed linear motor and the second doubly fed linear motor respectively.

[0014] Based on the slip frequency, the slip power of the first doubly fed linear motor and the second doubly fed linear motor is adjusted by adjusting the magnitude of the balancing force.

[0015] Optionally, by controlling the slip frequency of the first doubly fed linear motor, the first doubly fed linear motor is controlled to operate in subsynchronous mode; by controlling the slip frequency of the second doubly fed linear motor, the second doubly fed linear motor is controlled to operate in supersynchronous mode.

[0016] Optionally, after superimposing the balancing force, the resultant force of the secondary windings of the first doubly fed linear motor is the driving force, and the resultant force of the secondary windings of the second doubly fed linear motor is the braking force. The resultant force of the driving force and the braking force satisfies the total resistance load applied to the first and second doubly fed linear motors.

[0017] Optionally, the driving force of the first doubly-fed linear motor is controlled by controlling the product of the orthogonal components of the primary and secondary power supply currents of the first doubly-fed linear motor; and the braking force of the second doubly-fed linear motor is controlled by controlling the product of the orthogonal components of the primary and secondary power supply currents of the second doubly-fed linear motor.

[0018] Optionally, before the step of superimposing a pair of equal and opposite balancing forces on the secondary windings of the first and second doubly-fed linear motors, the method further includes:

[0019] Whether the total resistance load applied to the first doubly fed linear motor and the second doubly fed linear motor meets the preset balance force application condition, wherein the preset balance force application condition includes: the total resistance load is less than the preset force threshold.

[0020] To achieve the above objectives, the present invention also provides a maglev train that, under parking, static levitation, low-speed driving, low-acceleration driving, or low-deceleration driving conditions, employs the above-mentioned slip power control method. The primary windings of the first doubly-fed linear motor and the second doubly-fed linear motor are used as the stator of the maglev train and are laid along the track. The secondary windings of the first doubly-fed linear motor and the second doubly-fed linear motor are used as the mover of the maglev train and are fixed to the carriage of the maglev train.

[0021] Optionally, the yaw torque generated by the balancing forces superimposed on the secondary windings of the first and second doubly fed linear motors is balanced by the guidance system of the maglev train.

[0022] To achieve the above objectives, the present invention also provides a slip power control device for a linear motor, the slip power control device for the linear motor comprising:

[0023] The acquisition module is used to control the first doubly fed linear motor and the second doubly fed linear motor to generate different primary power supply frequencies, thereby obtaining different slip frequencies;

[0024] The superposition module is used to control the first doubly fed linear motor and the second doubly fed linear motor to generate the required combined driving force, and to control the superposition of a pair of equal and opposite balancing forces on the secondary windings of the first doubly fed linear motor and the second doubly fed linear motor respectively.

[0025] The adjustment module is used to adjust the slip power of the first doubly fed linear motor and the second doubly fed linear motor by adjusting the magnitude of the balancing force according to the slip frequency.

[0026] To achieve the above objectives, the present invention also provides a terminal device, the terminal device including a memory, a processor, and a linear motor slip power control program stored in the memory and executable on the processor, wherein when the linear motor slip power control program is executed by the processor, it implements the steps of the linear motor slip power control method as described above.

[0027] Furthermore, to achieve the above objectives, the present invention also proposes a computer-readable storage medium storing a slip power control program for a linear motor, wherein when the slip power control program for the linear motor is executed by a processor, the program implements the steps of the slip power control method for the linear motor as described above.

[0028] To achieve the above objectives, the present invention also provides a computer program product, the computer program product comprising a computer program, which, when executed by a processor, implements the steps of the slip power control method for a linear motor as described above.

[0029] This invention provides a method for controlling the slip power of a linear motor, a maglev train, a device, a terminal equipment, a computer-readable storage medium, and a computer program product. By controlling the first and second doubly-fed linear motors to generate different primary power supply frequencies, different slip frequencies are obtained. Under the premise of controlling the first and second doubly-fed linear motors to generate the required combined driving force, a pair of equal and opposite balancing forces are superimposed on the secondary windings of the first and second doubly-fed linear motors respectively. Based on the slip frequency, the slip power of the first and second doubly-fed linear motors is adjusted by regulating the magnitude of the balancing forces.

[0030] As can be seen, compared to existing linear motor control methods that directly control slip power using slip frequency, this invention achieves precise slip power control even with a limited slip frequency by superimposing equal and opposite balancing forces on the first and second doubly-fed linear motors. This slip power is then used to power the movers (i.e., the carriages) of the maglev train. This allows for slip power adjustment even when the doubly-fed linear motors are operating under under-reaction force conditions. In the maglev train application, the guiding system balances the yaw torque caused by the superimposed balancing forces on the movers of the left and right linear motors, maintaining stable operation of the maglev train. Furthermore, this invention is applicable not only to maglev trains but also to other equipment employing linear motors. Attached Figure Description

[0031] Figure 1 is a schematic diagram of the hardware operating environment involved in the embodiment of the present invention;

[0032] Figure 2 is a flowchart illustrating an embodiment of the slip power control method for linear motors according to the present invention;

[0033] Figure 3 is a schematic diagram of the application of balancing force in an embodiment of the slip power control method for linear motors of the present invention;

[0034] Figure 4 is a schematic diagram of maglev train parameters according to an embodiment of the slip power control method of the linear motor of the present invention;

[0035] Figure 5 is a schematic diagram of the steady-state running resistance of a maglev train according to an embodiment of the slip power control method of the linear motor of the present invention.

[0036] Figure 6 is a schematic diagram of the yaw distance balance of a maglev train according to an embodiment of the slip power control method of the linear motor of the present invention.

[0037] Figure 7 is a functional module schematic diagram of an embodiment of the slip power control device for linear motors of the present invention.

[0038] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0039] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0040] As shown in Figure 1, Figure 1 is a schematic diagram of the device structure of the hardware operating environment involved in the embodiment of the present invention.

[0041] The terminal device in this embodiment of the invention can be a maglev train or other linear maglev transportation systems, such as a servo processing platform, a conveying device, or other horizontal motion equipment. The terminal device in this embodiment can be used to realize the slip power control of the doubly fed linear motor in the scenario of insufficient reaction force in the linear maglev transportation system.

[0042] As shown in Figure 1, the terminal device may include: a processor 1001, such as a CPU; a network interface 1004; a user interface 1003; a memory 1005; and a communication bus 1002. The communication bus 1002 is used to enable communication between these components. The user interface 1003 may include a display screen and an input unit such as a keyboard. Optionally, the user interface 1003 may also include a standard wired interface or a wireless interface. The network interface 1004 may optionally include a standard wired interface or a wireless interface (such as a Wi-Fi interface). The memory 1005 may be high-speed RAM or non-volatile memory, such as a disk drive. Optionally, the memory 1005 may also be a storage device independent of the aforementioned processor 1001.

[0043] Those skilled in the art will understand that the device structure shown in Figure 1 does not constitute a limitation on the slip power control device for a linear motor, and may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0044] As shown in Figure 1, the memory 1005, which serves as a computer storage medium, may include an operation module, a network communication module, a user interface module, and a slip power control program for the linear motor. The operation module is a program that manages and controls the hardware and software resources of the device, supporting the operation of the slip power control program for the linear motor and other software or programs. In the device shown in Figure 1, the user interface 1003 is mainly used for data communication with the client; the network interface 1004 is mainly used for establishing a communication connection with the server; and the processor 1001 can be used to call the slip power control program for the linear motor stored in the memory 1005 and perform the following operations:

[0045] By controlling the first doubly fed linear motor and the second doubly fed linear motor to generate different primary power supply frequencies, different slip frequencies can be obtained;

[0046] Under the premise of controlling the first doubly fed linear motor and the second doubly fed linear motor to generate the required combined driving force, a pair of equal and opposite balancing forces are superimposed on the secondary windings of the first doubly fed linear motor and the second doubly fed linear motor respectively.

[0047] Based on the slip frequency, the slip power of the first doubly fed linear motor and the second doubly fed linear motor is adjusted by adjusting the magnitude of the balancing force.

[0048] Furthermore, the processor 1001 can be used to call the linear motor slip power control program stored in the memory 1005 and perform the following operations:

[0049] By controlling the slip frequency of the first doubly fed linear motor, the first doubly fed linear motor is controlled to operate in subsynchronous mode; by controlling the slip frequency of the second doubly fed linear motor, the second doubly fed linear motor is controlled to operate in supersynchronous mode.

[0050] Furthermore, after superimposing the balancing force, the resultant force of the secondary windings of the first doubly fed linear motor is the driving force, and the resultant force of the secondary windings of the second doubly fed linear motor is the braking force. The resultant force of the driving force and the braking force satisfies the total resistance load applied to the first and second doubly fed linear motors.

[0051] Furthermore, the processor 1001 can be used to call the linear motor slip power control program stored in the memory 1005 and perform the following operations:

[0052] The driving force of the first doubly-fed linear motor is controlled by controlling the product of the orthogonal components of the primary and secondary power supply currents of the first doubly-fed linear motor; the braking force of the second doubly-fed linear motor is controlled by controlling the product of the orthogonal components of the primary and secondary power supply currents of the second doubly-fed linear motor.

[0053] Furthermore, before the step of superimposing a pair of equal and opposite balancing forces on the secondary windings of the first and second doubly-fed linear motors, the processor 1001 can call the slip power control program for the linear motors stored in the memory 1005 and perform the following operations:

[0054] Whether the total resistance load applied to the first doubly fed linear motor and the second doubly fed linear motor meets the preset balance force application condition, wherein the preset balance force application condition includes: the total resistance load is less than the preset force threshold.

[0055] In this invention, according to the background art, existing doubly-fed linear motor control is unsuitable for scenarios where the doubly-fed linear motor is under-reaction, such as when a maglev train is in coasting mode (i.e., traveling at a slow speed) and does not generate sufficient air resistance, thus the doubly-fed linear motor will exhibit insufficient driving force. In such cases, according to the slip power equation described above, the doubly-fed linear motor cannot generate sufficient slip power, or requires a very high slip frequency, resulting in very high reactive power and extremely high inverter capacity.

[0056] In order to enable the doubly fed linear motor to be applicable to its under-reaction force scenario and improve the precise and efficient control of slip power, so as to further utilize slip power to provide non-contact power supply to the mover (i.e. the carriage of the maglev train), this invention proposes a slip power control method for the doubly fed linear motor, which solves the problem of maintaining or controlling slip power when the doubly fed linear motor is in the under-reaction force condition.

[0057] Referring to Figure 2, which is a flowchart of the first embodiment of the slip power control method for linear motors of the present invention.

[0058] This invention provides an embodiment of a slip power control method for a linear motor. It should be noted that although the logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than that shown here.

[0059] Specifically, the slip power control method for the linear motor in this embodiment can be applied to maglev trains. The maglev train includes a slip power control system, which comprises a first doubly-fed linear motor and a second doubly-fed linear motor, as shown in Figure 3. The primary winding of the doubly-fed linear motor is used for the stator of the maglev train, which is laid along the track. The secondary winding of the doubly-fed linear motor is used for the mover of the maglev train and is fixed to the carriage of the maglev train. Based on this, the slip power control method for the linear motor of the present invention specifically includes the following steps:

[0060] Step S10: Control the first doubly fed linear motor and the second doubly fed linear motor to generate different primary power supply frequencies, thereby obtaining different slip frequencies;

[0061] In this embodiment, the maglev train controls the first feedback linear motor and the second feedback linear motor to generate an initial power supply frequency. Since the initial power supply frequencies generated by the first feedback linear motor and the second feedback linear motor are different at this time, the slip power of the first doubly fed linear motor and the second doubly fed linear motor is also different.

[0062] Step S20: Under the premise of controlling the first doubly fed linear motor and the second doubly fed linear motor to generate the required combined driving force, respectively control the superposition of a pair of equal and opposite balancing forces on the secondary windings of the first doubly fed linear motor and the second doubly fed linear motor.

[0063] It should be noted that, in this embodiment, as shown in Figure 3, the total resistance load F z In cases where the total reaction force is insufficient or zero, in order to control the doubly fed linear motor to generate sufficient slip power in a slip frequency-limited scenario, a pair of balancing forces can be superimposed on the doubly fed linear motor to achieve precise control or maintenance of the slip power.

[0064] Specifically, for example, in this embodiment, the first doubly fed linear motor and the second doubly fed linear motor can be controlled to generate a first balancing force F0 and a second balancing force -F0 that are equal in magnitude and opposite in direction, respectively, according to the power supply requirements of the maglev train.

[0065] Furthermore, after obtaining the first balancing force F0 and the second balancing force -F0, which are equal in magnitude and opposite in direction, generated by the first doubly fed linear motor and the second doubly fed linear motor respectively, as shown in Figure 3, the first balancing force F0 can be superimposed on the first doubly fed linear motor, and the second balancing force -F0 can be superimposed on the second doubly fed linear motor.

[0066] Based on this, as shown in Figure 3, the force superimposed on the secondary winding of the first doubly fed linear motor (used as the mover of the maglev train, and fixed to the maglev train car) (in this embodiment, this force is the driving force) is:

[0067]

[0068] The force superimposed on the secondary (fixed) of the second doubly fed linear motor (in this embodiment, this force is the braking force) is:

[0069]

[0070] It can be seen that the resultant force of the driving force and braking force mentioned above is F. z It is equal to its total reaction force or total resistance load.

[0071] At this point, the slip power of the first doubly fed linear motor can be expressed as:

[0072]

[0073] The slip power of the second doubly fed linear motor can be expressed as:

[0074]

[0075] Step S30: Based on the slip frequency, adjust the slip power of the first doubly fed linear motor and the second doubly fed linear motor by adjusting the magnitude of the balancing force.

[0076] In this embodiment, based on the above description, the slip power of the first doubly fed linear motor can be expressed as:

[0077]

[0078] The slip power of the second doubly fed linear motor can be expressed as:

[0079]

[0080] Based on this, the slip power P of the first doubly fed linear motor can be adjusted by adjusting the magnitude of the balancing force. er1 The slip power P of the second doubly fed linear motor er2 .

[0081] In another embodiment, ω can also be adjusted. f1 and ω f2 The sign of ω. Specifically, ω can be... f1 Adjust to a positive value (ω) f1>0), thus enabling the first doubly fed linear motor to supply power to the electrical load on its mover; ω f2 Adjust to a negative value (ω) f2 If <0), the second doubly fed linear motor can supply power to the electrical load on its mover.

[0082] Additionally, if the doubly fed linear motor is under reaction force or total resistance load F z In scenarios where there is insufficient balance (such as when a maglev train is coasting), the applied balancing force can be controlled. Right now,

[0083] As can be seen, in this embodiment, F0 and ω can be adjusted. f1 and ω f2 Adjustment to achieve F z In cases of insufficient power, the slip power of the first doubly fed linear motor and the second linear doubly fed motor is adjusted.

[0084] In this embodiment, under the reaction force or total resistance load F z In cases where the slip power is insufficient or zero, to control the doubly-fed linear motors to generate sufficient slip power in scenarios with limited slip frequency, the first and second doubly-fed linear motors can be controlled to generate a first balancing force F0 and a second balancing force -F0 of equal magnitude but opposite direction. Furthermore, the first balancing force F0 can be superimposed on the first doubly-fed linear motor, and the second balancing force -F0 can be superimposed on the second doubly-fed linear motor to obtain the slip power corresponding to the first and second doubly-fed linear motors, respectively. The slip power of the first and second doubly-fed linear motors can be adjusted by regulating the magnitude of these balancing forces.

[0085] As can be seen, compared to the existing technology that directly controls the slip frequency using linear motor control, this invention, by superimposing equal and opposite balancing forces on the first and second doubly-fed linear motors, can still achieve precise and efficient control of the slip power even when the slip frequency is limited. This slip power is then used to power the mover (i.e., the carriage) of the maglev train. This achieves slip power adjustment even when the doubly-fed linear motors are operating under under-reaction force conditions.

[0086] In addition to being applicable to maglev trains, this invention is also generally applicable to other devices that use linear motors.

[0087] Furthermore, based on the first embodiment of the slip power control method for linear motors of the present invention, a second embodiment of the slip power control method for linear motors of the present invention is proposed.

[0088] In this embodiment, by controlling the slip frequency of the first doubly fed linear motor, the first doubly fed linear motor is controlled to operate in subsynchronous mode; by controlling the slip frequency of the second doubly fed linear motor, the second doubly fed linear motor is controlled to operate in supersynchronous mode.

[0089] In this embodiment, according to the above description, the slip frequency ω of the first doubly fed linear motor is... f1 When adjusted to a positive value, the first doubly-fed linear motor operates in subsynchronous mode; when the slip frequency ω of the second doubly-fed linear motor is... f2 When the value is adjusted to negative, the second doubly fed linear motor operates in supersynchronous mode.

[0090] As can be seen, in this embodiment, the secondary windings of both the first and second doubly fed linear motors operate in power feeding mode, which meets the power feeding requirements of the moving side of the maglev train.

[0091] Furthermore, after superimposing the balancing force, the resultant force of the secondary windings of the first doubly fed linear motor is the driving force, and the resultant force of the secondary windings of the second doubly fed linear motor is the braking force. The resultant force of the driving force and the braking force satisfies the total resistance load applied to the first and second doubly fed linear motors.

[0092] In this embodiment, as shown in Figure 3, after the first balancing force and the second balancing force are applied to the secondary windings of the first doubly-fed DC motor and the second doubly-fed DC motor respectively, the resultant force of the secondary winding of the first doubly-fed DC motor is: The resultant force at this point is the driving force; the resultant force of the secondary winding of the second doubly-fed DC motor is... The combined force at this point is the braking force.

[0093] It can be seen that the resultant force of the driving force and braking force mentioned above is F. z .

[0094] Based on this, as described above, the slip power of the first doubly fed linear motor can be expressed as:

[0095]

[0096] The slip power of the second doubly fed linear motor can be expressed as:

[0097]

[0098] As can be seen, in this embodiment, by adjusting the balancing force, not only can the slip function be precisely controlled, but the slip frequency of the doubly fed linear motor can also be limited to a small range, thereby reducing the reactive power requirement and further reducing the capacity requirement of the inverter on the moving side of the maglev train.

[0099] Furthermore, the driving force of the first doubly-fed linear motor is controlled by controlling the product of the orthogonal components of the primary and secondary power supply currents of the first doubly-fed linear motor; the braking force of the second doubly-fed linear motor is controlled by controlling the product of the orthogonal components of the primary and secondary power supply currents of the second doubly-fed linear motor.

[0100] It should be noted that, in this embodiment, the driving force applied to the first doubly-fed linear motor and the second doubly-fed linear motor is taken into account. and braking force In essence, both are traction forces Fx, which can be specifically expressed as:

[0101]

[0102] Among them, i s i represents the amplitude of the primary current of the doubly-fed linear motor. r i represents the amplitude of the secondary current of the doubly-fed linear motor. r The angle between the primary current and secondary current vectors of a doubly fed linear motor is given.

[0103] Based on the above traction force F x The expression indicates that, in this embodiment, the driving force of the first doubly-fed linear motor can be controlled by controlling the product of the orthogonal components of the primary and secondary power supply currents of the first doubly-fed linear motor, and the braking force of the second doubly-fed linear motor can be controlled by controlling the product of the orthogonal components of the primary and secondary power supply currents of the second doubly-fed linear motor. The aforementioned product of the orthogonal components of the power supply currents is L in the above formula. m i s i r sin(β).

[0104] Through the above methods, this embodiment can control the driving force / braking force, and flexibly adjust or maintain the slip power.

[0105] Furthermore, before step S20 above, "controlling the superposition of a pair of equal and opposite balancing forces on the secondary windings of the first and second doubly-fed linear motors", the following may also be included:

[0106] Step S40: Determine whether the total resistance load applied to the first doubly fed linear motor and the second doubly fed linear motor meets the preset balance force application condition, wherein the preset balance force application condition includes: the total resistance load is less than the preset force threshold.

[0107] The slip power control method for doubly fed linear motors in this embodiment only applies to F.z In the case of insufficient or zero, once the reaction force requirement reaches a level that can generate sufficient slip power, there is no need to superimpose the pair of equal and opposite balancing forces, i.e., F0 = 0.

[0108] Therefore, before superimposing a pair of equal and opposite balancing forces on the secondary windings of the first and second doubly-fed linear motors, it is necessary to determine whether the current total reaction force is less than a preset force threshold. If the current reaction force is less than the preset force threshold, it means that the current F... z If the value is insufficient or even zero, a pair of equal and opposite balancing forces F0 can be superimposed on the secondary windings of the first and second doubly fed linear motors.

[0109] Therefore, in this invention, by superimposing a pair of equal-sized, opposite-direction balancing forces on the first and second doubly-fed linear motors symmetrically arranged on the left and right sides, the driving force or braking force on the first or second linear motor can be increased, thus satisfying the adjustment of slip power when the slip frequency is limited. Furthermore, by controlling the slip frequency of the first doubly-fed linear motor to operate in sub-synchronous mode and making the resultant force of the secondary windings of the first doubly-fed linear motor a driving force; and by controlling the slip frequency of the second doubly-fed linear motor to operate in super-synchronous mode and making the resultant force of the secondary windings of the second doubly-fed linear motor a braking force, both the secondary windings of the first and second linear motors operate in feed mode, satisfying the feed power requirements on the mover side. Simultaneously, the slip frequency of the doubly-fed linear motors can be limited to a small range, resulting in lower reactive power requirements, thus reducing the capacity requirements of the inverter on the mover side.

[0110] Furthermore, based on the first and second embodiments of the slip power control method for linear motors of the present invention, a third embodiment of the present invention is proposed. In this embodiment, a maglev train is proposed, which adopts the slip power control method of the first and second embodiments described above.

[0111] In this embodiment, the maglev train, under parking, static levitation, low-speed driving, low-acceleration driving, or low-deceleration driving conditions, can adjust the slip power of the first and second doubly-fed linear motors by superimposing the first balancing force F0 and the second balancing force -F0 described in the above embodiment on the primary and secondary components of the first and second doubly-fed linear motors, respectively. The primary components of the first and second doubly-fed linear motors serve as the stator of the maglev train and are laid along the track. The secondary components of the first and second doubly-fed linear motors serve as the mover of the maglev train and are fixed to the carriage of the maglev train.

[0112] Furthermore, the yaw torque generated by the balancing forces superimposed on the secondary windings of the first and second doubly fed linear motors is balanced by the guidance system of the maglev train.

[0113] In this embodiment, the parameters of a doubly-fed linear motor type maglev train are shown in Figure 4. With a 10mm air gap, the mover current is approximately 65A to maintain the rated levitation force. At this time, the total excitation loss of the 16 mover units in one train is approximately:

[0114]

[0115] Taking into account the power required for vehicle lighting, air conditioning and steering, the total slip power is estimated to be approximately 200kW.

[0116] Due to the limitations of the on-board DC voltage (inverter DC bus voltage), the moving-side voltage should be less than or equal to 630V.

[0117] The maximum limit for slip frequency is:

[0118]

[0119] According to the slip power formula of a doubly fed linear motor:

[0120]

[0121] To meet the requirement of 200kW slip power, one train car needs to provide a total thrust of 17kN, which corresponds to 1080N per moving unit.

[0122] The main resistance experienced by high-speed maglev trains during operation is air resistance, which can be expressed as:

[0123]

[0124] Where C d Let ρ be the drag coefficient, ρ be the air density, A be the frontal area of ​​the maglev train, and V be the relative wind speed. In the absence of natural wind, the relative wind speed V is the train speed.

[0125] Figure 5 shows the resistance experienced by a single train car during operation. It can be seen that when the maglev train is coasting (at a very low speed), its running resistance is very small. Based on the principle of force balance, using the normal operating mode, the required driving force F on both sides is... x :

[0126]

[0127] Therefore, when the maglev train is coasting, F x It is very small, even close to 0 under extremely low-speed coasting conditions.

[0128] It can be seen that when the slip frequency is limited, it is impossible to meet the sufficient slip power requirement, or a very high slip frequency ω is required. f This results in extremely high reactive power and inverter capacity.

[0129] However, a pair of opposing balancing forces are added to the left and right sides, so that one side is controlled as the driving force and the other as the braking force; the slip frequency is controlled so that the driving force side is in a subsynchronous state and the braking force side is in a supersynchronous state, and the absolute value of the slip frequency is kept at the upper limit. That is:

[0130]

[0131]

[0132] ω f1 =-ω f2 =ω fmax #(8)

[0133] The total slip power is:

[0134]

[0135] To meet the slip power requirement, adding a pair of balancing forces of 540N will suffice.

[0136] Based on this, it can be understood that the maglev train will be subjected to a yaw moment, and the yaw moment of a suspension frame is:

[0137]

[0138] Among them, L b The width interval between the moving subunits on the left and right sides of the train is approximately 3.3m.

[0139] This yaw moment can be overcome by applying a guiding force through the guidance control system. As shown in Figure 6, a single suspension frame has six guiding magnetic poles on one side, divided into upper and lower layers. The yaw moment can be suppressed by applying guiding forces on both diagonal sides. Considering the force on a single suspension frame, two guiding magnetic poles will be involved on each side, and the guiding force F that a single electromagnet needs to apply is... y Satisfy the following formula:

[0140] 2F y L a =T yaw

[0141] Among them, L a The distance between the centroids of the two furthest guide magnetic poles in the magnetic travel direction of a single suspension frame is approximately 2 meters. According to the above formula, the guiding force required for each guide magnetic pole is approximately 450 N. Based on relevant literature (Zhao Chunxia. Research on Guiding Dynamics of EMS-type High-Speed ​​Maglev Train [D]. National University of Defense Technology, 2014), the relationship between the electromagnetic force and current of the guide magnetic poles can be obtained. Under the condition of a rated guide air gap of 11 mm, the current flowing through a single guide magnetic pole is approximately 12 A. It can be seen that the guiding force and current required for the guide magnetic poles are relatively small compared to the rated capacity of the guide magnetic poles, making implementation easy.

[0142] In addition, according to the above

[0143]

[0144]

[0145] It can be seen that if the load resistance F z If the value is zero, it represents a special case of static buoyancy, which still satisfies the conditions of the above control scheme.

[0146] Therefore, in this embodiment, the slip frequency and thrust direction of the doubly fed linear motors on both sides of the maglev train can be controlled by superimposing balancing forces, allowing them to operate in subsynchronous drive and supersynchronous braking states respectively for coasting conditions. Furthermore, the guiding system on the maglev train can be used to balance the yaw torque caused by the superimposed balancing forces on the left and right linear motor movers, maintaining the stable operation of the maglev train.

[0147] Furthermore, this embodiment of the invention also proposes a slip power control device for a linear motor. Referring to FIG7, the slip power control device for the linear motor includes:

[0148] The acquisition module 10 is used to control the first doubly fed linear motor and the second doubly fed linear motor to generate different primary power supply frequencies, thereby obtaining different slip frequencies;

[0149] The superposition module 20 is used to control the first doubly fed linear motor and the second doubly fed linear motor to generate the required combined driving force, and to respectively control the superposition of a pair of equal and opposite balancing forces on the secondary windings of the first doubly fed linear motor and the second doubly fed linear motor.

[0150] The adjustment module 30 is used to adjust the slip power of the first doubly fed linear motor and the second doubly fed linear motor by adjusting the magnitude of the balancing force according to the slip frequency.

[0151] The extended content of the specific implementation of the slip power control device for linear motor of the present invention is basically the same as the various embodiments of the slip power control method for linear motor described above, and will not be repeated here.

[0152] Furthermore, embodiments of the present invention also propose a computer-readable storage medium storing a slip power control program for a linear motor. When the slip power control program for the linear motor is executed by a processor, it implements the steps of the slip power control method for the linear motor as described below.

[0153] The various embodiments of the slip power control device and computer-readable storage medium for the linear motor of the present invention can be referred to the various embodiments of the slip power control method for the linear motor of the present invention, and will not be repeated here.

[0154] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.

[0155] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0156] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal device (which can be a maglev train, or a mobile phone, tablet computer, server, or other network device, etc.) to execute the methods described in the various embodiments of the present invention.

[0157] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural or procedural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.

Claims

1. A slip power control method for a linear motor, characterized in that, The slip power control method is applied to a linear maglev vehicle system, which includes a first doubly-fed linear motor and a second doubly-fed linear motor symmetrically arranged on both sides. Both the first and second doubly-fed linear motors comprise a primary and a secondary. The primary is fixedly arranged, and the secondary is mounted on the same moving vehicle component that can perform linear motion relative to the primary. The slip power control method includes: controlling the first and second doubly-fed linear motors to generate different primary power supply frequencies, thereby obtaining different slip frequencies; and, under the premise of controlling the first and second doubly-fed linear motors to generate the required combined driving force, separately controlling the first and second doubly-fed linear motors... A pair of equal and opposite balancing forces are superimposed on the secondary windings of two doubly fed linear motors; the first doubly fed linear motor is superimposed with a first balancing force, and the second doubly fed linear motor is superimposed with a second balancing force, the first and second balancing forces being equal in magnitude and opposite in direction; based on the slip frequency, the slip power of the first and second doubly fed linear motors is adjusted by adjusting the magnitude of the balancing forces; the slip power adjustment method for the first doubly fed linear motor is to adjust the slip frequency of the first doubly fed linear motor or to adjust the magnitude and direction of the first balancing force; the slip power adjustment method for the second doubly fed linear motor is to adjust the slip frequency of the second doubly fed linear motor or to adjust the magnitude and direction of the second balancing force.

2. The slip power control method according to claim 1, characterized in that, By controlling the slip frequency of the first doubly fed linear motor, the first doubly fed linear motor is controlled to operate in subsynchronous mode; by controlling the slip frequency of the second doubly fed linear motor, the second doubly fed linear motor is controlled to operate in supersynchronous mode.

3. The slip power control method according to claim 1, characterized in that, After the balancing forces are superimposed, the resultant force of the secondary windings of the first doubly fed linear motor is the driving force, and the resultant force of the secondary windings of the second doubly fed linear motor is the braking force. The resultant force of the driving force and the braking force satisfies the total resistance load applied to the first and second doubly fed linear motors.

4. The slip power control method according to claim 3, characterized in that, The driving force of the first doubly-fed linear motor is controlled by controlling the product of the orthogonal components of the primary and secondary power supply currents of the first doubly-fed linear motor; the braking force of the second doubly-fed linear motor is controlled by controlling the product of the orthogonal components of the primary and secondary power supply currents of the second doubly-fed linear motor.

5. The slip power control method according to claim 1, characterized in that, Before the step of superimposing a pair of equal and opposite balancing forces on the secondary windings of the first and second doubly fed linear motors, the method further includes: determining whether the total resistance load applied to the first and second doubly fed linear motors meets a preset balancing force application condition, wherein the preset balancing force application condition includes: the total resistance load is less than a preset force threshold.

6. A maglev train, characterized in that, Under parking, static levitation, low-speed driving, low-acceleration driving, or low-deceleration driving conditions, the slip power control method as described in any one of claims 1-5 is adopted. The primary windings of the first doubly fed linear motor and the second doubly fed linear motor are used as the stator of the maglev train and are laid along the track. The secondary windings of the first doubly fed linear motor and the second doubly fed linear motor are used as the mover of the maglev train and are fixed to the carriage of the maglev train.

7. The maglev train according to claim 6, characterized in that, The yaw torque generated by the balancing forces superimposed on the secondary windings of the first and second doubly fed linear motors is balanced by the guidance system of the maglev train.

8. A terminal device, characterized in that, The terminal device includes a memory, a processor, and a linear motor slip power control program stored in the memory and executable on the processor. When the linear motor slip power control program is executed by the processor, it implements the steps of the linear motor slip power control method as described in any one of claims 1 to 5.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a slip power control program for a linear motor, which, when executed by a processor, implements the steps of the slip power control method for a linear motor as described in any one of claims 1 to 5.

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