Combined feeder handcart centralized control system

Abstract

This invention relates to the field of low-voltage power distribution system technology, and in particular to a centralized control system for combined power supply trolleys, comprising the following steps: S1: constructing a control architecture; S2: the host computer sends a trolley in / out command to the PLC controller (16) via communication, and the PLC controller (16) first determines whether the initial operating conditions of the corresponding trolley are met; S3: if the initial conditions are met, the zigzag plate (9) and the trolley mechanism above it move synchronously back and forth along the platform (8); S4: when the motor current value calculated by the PLC is greater than 1.3A, overcurrent protection is triggered; S5: the motor starting circuit of other trolleys is locked; S6: the motor (6) is controlled to reverse and push to the test position. This invention fully utilizes the internal space of the equipment by installing the electric push-pull mechanism inside the front door flange and adopting a compact transmission structure of platform-slider-zigzag plate and a multi-trolley horizontal parallel arrangement design. The separate assembly method of the electric push-pull mechanism and the 400A mechanism adapts to the assembly requirements of trolleys of different specifications.

Description

Technical Field

[0001] This invention relates to the field of low-voltage power distribution system technology, and in particular to a centralized control system for combined power supply trolleys. Background Technology

[0002] In recent years, the market has put forward clear requirements for intelligent functions of 1140V low-voltage power distribution systems. Among them, the integration of handcarts and the functions of local and remote electric handcart input and output are the core components of intelligent requirements. However, compared with the technically mature 10(6)kV power distribution system, there is currently no standardized electric handcart design scheme in the field of 1140V low-voltage power distribution, especially in the electric control of multi-handcart combined power distribution systems, where there is a lack of mature centralized control technology.

[0003] Traditional high and low voltage combined electrical switchgear control methods are mainly divided into two categories: one is to adopt unit independent control, that is, each switchgear unit is equipped with an independent control system. Although this method can ensure the control safety of each unit and has complete protection and interlocking functions, it has extremely high requirements for the capacity of the control power supply in combined electrical switchgear application scenarios, which can easily lead to the waste of power resources; the other is a simple combined control scheme, but this type of scheme generally has obvious deficiencies in the overload protection design of the switchgear motor and the integrity of mechanical and electrical interlocking logic, and cannot meet the safe operation requirements of 1140V low voltage power supply system.

[0004] For example, patent document with patent application number CN201911080622.9 discloses a servo system-based handcart control system and control method. Its main structure includes a control module, a drive unit, a servo motor, a torque acquisition unit, and a live acquisition unit for obtaining whether the handcart compartment is energized. The control module, drive unit, and servo motor are bidirectionally connected in sequence. The live acquisition unit is bidirectionally connected to the control module, and the torque acquisition unit is bidirectionally connected to the control module.

[0005] As can be seen from the above description of the system, it has the following drawbacks in its use: First, the system is mainly designed for the control of a single handcart and does not involve a centralized control scheme for multiple handcarts. It is not applicable to the application scenario of 1140V low-voltage combined power supply for multiple handcarts. If it is used for the control of multiple handcarts, multiple independent systems need to be equipped, which will not only significantly increase the size of the equipment and production costs, but also further increase the requirements for the control power supply capacity, which is contrary to the integration requirements of combined electrical appliances.

[0006] Secondly, the system lacks a precise current protection design for low-voltage handcart motors. It does not set matching protection thresholds based on the operating characteristics of 1140V low-voltage handcart motors (such as normal operating current of 0.7A and resistance current of about 1.5A). At the same time, it lacks linkage interlocking logic between handcart position and door opening and closing. In actual operation, it is easy to cause equipment failure due to motor overcurrent or door misoperation.

[0007] It is necessary to design a combined power supply truck centralized control system and control method suitable for 1140V low-voltage scenarios and capable of centralized control of multiple trucks. Summary of the Invention

[0008] To solve one of the above-mentioned technical problems, the present invention adopts the following technical solution: a control method for a centralized control system of a combined power supply trolley, comprising the following steps: S1: constructing a control architecture, the architecture comprising multiple low-voltage circuit breaker trolleys, multiple electric push-pull mechanisms corresponding one-to-one with the trolleys, a PLC controller (16) and a drive unit; each electric push-pull mechanism is installed in the front door flange, and a lead screw (4) extending along the length of the platform is provided above its horizontally arranged platform (8), the lead screw (4) is threadedly engaged with a slider (5), and a Z-shaped plate (9) is fixedly connected to the upper surface of the slider (5), the Z-shaped plate (9) 9) The upper part is connected to the core of the low-voltage circuit breaker trolley (the bottom of the core is attached to the upper surface of the platform 8); the electric push-pull mechanism housing is equipped with a motor (6), and the motor (6) is connected to the lead screw (4) for transmission; the drive unit includes a protection current transmitter unit (17), a rectifier unit (18), a fuse (19), a current transformer (20), a power switching relay (21), a forward and reverse relay (22), an AC127V power interface (23), an AC24V power interface (24), and a multi-channel drive output unit (25), and the drive unit is shared by multiple trolleys, and only one trolley is controlled at the same time.

[0009] S2: The host computer sends the handcart in / out command to the PLC controller (16) via communication. The PLC controller (16) first determines whether the initial operating conditions of the corresponding handcart are met.

[0010] S3: If the initial conditions are met, the PLC controller (16) controls the motor (6) of the corresponding handcart to rotate forward / reverse through the output contacts. The motor (6) drives the lead screw (4) to rotate, and the slider (5) moves back and forth along the platform (8), thereby driving the zigzag plate (9) and the handcart mechanism above to move back and forth along the platform (8) synchronously.

[0011] S4: When the motor (6) is running, the current transformer (20) installed on the motor power supply line collects the motor current and transmits it to the A0 interface of the PLC controller (16) through the protection current transmitter unit (17). When the motor current value obtained by the PLC calculation is greater than 1.3A, the overcurrent protection is triggered.

[0012] S5: By monitoring the motor current of the currently running handcart, the motor starting circuit of other handcarts is blocked.

[0013] S6: After the system is powered on, the PLC controller (16) monitors the position of each handcart and controls the motor (6) to reverse and push the handcart that is in the middle position above the platform (8) when it is not working or not being tested to the test position.

[0014] Based on any of the above technical solutions, the following further optimization is made: the initial conditions for the handcart to be jacked in step S2 are X0=1 (circuit breaker not closed), X1=0 (handcart in the test position above platform 8), and X2=1 (handcart not in the working position above platform 8); the jacking in control process in step S3 is as follows: the output contact Y1 of the PLC controller (16) controls the motor (6) to rotate in the forward direction, and the handcart moves along platform 8 to the working position; if X1 does not change from 0 to 1 within 2 seconds of Y1 issuing the signal (handcart has not left the test position), Y1 stops outputting and the motor (6) stops rotating; after X1 changes position normally, the motor (6) continues to run for about 5 seconds, and when X2 changes from 1 to 0 (handcart reaches the working position), the motor (6) stops rotating; if X1 does not change position within 8 seconds, it is determined to be a handcart fault, and the motor (6) stops rotating; where X is the PLC input signal address identifier, corresponding to the feedback signal of the handcart position sensor (monitoring the handcart position on platform 8) and the circuit breaker status switch.

[0015] Based on any of the above technical solutions, the following further optimization is made: the initial conditions for the handcart to be moved out in step S2 are X0=1 (circuit breaker not closed), X1=1 (handcart not in the test position above platform 8), and X2=0 (handcart in the working position above platform 8); the control process for moving out in step S3 is as follows: the output contact Y1 of the PLC controller (16) controls the motor (6) to rotate, and at the same time Y0 controls the motor (6) to reverse, and the handcart moves along platform 8 to the test position; if X2 does not change from 0 to 1 within 2 seconds of Y0 and Y1 issuing signals (the handcart has not left the working position), Y0 and Y1 stop outputting and the motor (6) stops rotating; after X2 changes position normally, the motor (6) continues to run for about 5 seconds, and when X1 changes from 1 to 0 (the handcart reaches the test position), the motor (6) stops rotating; if X2 does not change position within 8 seconds, it is determined that the handcart is faulty and the motor (6) stops rotating.

[0016] Based on any of the above technical solutions, the following optimization is made: The specific process of overcurrent protection in step S4 is as follows: When the handcart is running in the forward direction (moving along the platform 8 to the working position), the PLC controller (16) first stops the motor (6) from running in the forward direction, and then controls the motor (6) to reverse, driving the handcart to return to the test position along the platform 8; when the handcart is running in the reverse direction (moving along the platform 8 to the test position), the PLC controller (16) directly stops the motor (6) from running in the reverse direction, and the handcart stays at the current position of the platform 8 without returning to the working position.

[0017] Based on any of the above technical solutions, the following optimization is made: the process of locking the starting circuit of other handcart motors in step S5 is as follows: after the motor (6) of any handcart starts, the current of the motor is detected by the D8030 current detection register inside the PLC, and then the starting circuit of the motor of other handcarts is locked by the contact of the M100 auxiliary relay inside the PLC; after locking, the starting control point of other handcarts cannot output a signal to control the corresponding motor (6) drive output, ensuring that only one handcart moves on the platform 8 at the same time.

[0018] Based on any of the above technical solutions, the following optimization is made: The process of monitoring the position of the handcart in step S6 is as follows: During the first scanning cycle after the system is powered on, the M8003 initial pulse relay inside the PLC sends a holding signal to the M49 auxiliary relay, and the PLC controller (16) monitors the position of each handcart on the platform 8; If a handcart is in the middle position above the platform 8, the handcart motor (6) is triggered to rotate in the opposite direction and push the handcart to the test position; After the handcart is in position, the signal is transmitted to the next handcart detection program through the M90 ​​position signal relay inside the PLC; If the handcart fails to push back, the signal is transmitted to the next handcart detection program through the T61 delay timer inside the PLC and the current handcart detection is stopped; After all handcarts are monitored, the T90 delay timer inside the PLC sends a stop signal after 3 seconds, and the T50 delay timer stops the detection program after 2 seconds.

[0019] The present invention also includes a centralized control system for combined power supply trolleys, comprising: multiple low-voltage circuit breaker trolleys, multiple electric push-pull mechanisms corresponding to each trolley, a PLC controller (16) and a drive unit.

[0020] Each low-voltage circuit breaker trolley includes a core, the bottom of which is attached to the upper surface of the platform (8) of the electric push-pull mechanism, the side of the core is provided with a pin hole (1) and a guide pin (3), and the front end of the core is provided with a contact (2).

[0021] Each electric push-pull mechanism is installed inside the front door flange and includes a horizontally arranged platform (8), a lead screw (4) extending along the length of the platform (8), a slider (5) sleeved on the lead screw (4) and with its bottom attached to the upper surface of the platform (8), a zigzag plate (9) fixed on the upper surface of the slider (5), a motor (6) fixed to the end of the electric push-pull mechanism housing and connected to the lead screw (4), a locking shaft (14) horizontally passing through the side of the electric push-pull mechanism housing, a locking block (12) sleeved on the locking shaft (14) near the end of the slider (5), and a locking switch (7) set on the side of the electric push-pull mechanism housing and linked with the locking shaft (14); the zigzag plate (9) has a locking square hole (10) and a screw hole (11), which respectively cooperate with the guide pin (3) and pin hole (1) of the mechanism.

[0022] The drive unit includes a protection current transmitter (17), a rectifier (18), a fuse (19), a current transformer (20) installed on the power supply lines of each motor (6), a power switching relay (21), a forward and reverse relay (22), an AC127V power interface (23), an AC24V power interface (24), and a multi-drive output unit (25) integrated in the control box. The control box is fixed on the outside of the electric push-pull mechanism housing, and the drive unit is shared by multiple vehicles.

[0023] The PLC controller (16) is connected to the host computer. Its A0 interface is electrically connected to the protection current transmitter unit (17), and its output contacts are electrically connected to the forward and reverse relay (22). The system is set to 1.3A as the motor protection threshold. The locking shaft (14) is linked to the equipment door (15) at the end away from the slider (5).

[0024] Based on any of the above technical solutions, the following further optimizations are made: the electric push-pull mechanism and the 400A movement adopt a separate design; the guide pin (3) of the movement is horizontally inserted into the locking square hole (10) of the zig plate (9) to achieve radial positioning of the movement and the zig plate (9); the pin hole (1) of the movement and the thread hole (11) of the zig plate (9) are coaxially corresponding and fixed by M8 bolts so that when the zig plate (9) moves, it can drive the movement to move synchronously back and forth along the platform (8).

[0025] Based on any of the above technical solutions, the following further optimization is made: the connection relationship of each component in the drive unit is as follows: the output terminals of AC127V power interface (23) and AC24V power interface (24) are connected in series with the input terminal of fuse (19), the output terminal of fuse (19) is connected to the input terminal of rectifier unit (18); the output terminal of rectifier unit (18) is connected to the input terminal of power switching relay (21), the output terminal of power switching relay (21) is connected to the power terminal of forward and reverse relay (22); the output terminal of forward and reverse relay (22) is connected to the input terminal of multi-channel drive output unit (25), the output terminal of multi-channel drive output unit (25) is connected to the motor (6) of each handcart respectively; the output terminal of current transformer (20) is connected to the input terminal of protection current transmitter unit (17), the output terminal of protection current transmitter unit (17) is connected to the A0 interface of PLC controller (16).

[0026] Based on any of the above technical solutions, the following further optimization is made: The locking logic of the locking shaft (14) is as follows: When the system is running normally, the locking shaft (14) drives the locking block (12) to rotate 90° clockwise, so that the locking block (12) is disengaged from the locking area on the side of the slider (5), and at the same time, the locking switch (7) rotates 90° clockwise to conduct and connect the control power supply; after the slider (5) drives the handcart away from the test position on the platform (8), the locking block (12) cannot rotate counterclockwise, and the locking shaft (14) locks the door (15) in conjunction with the locking. When the slider (5) drives the handcart back to the test position on the platform (8), the locking shaft (14) rotates 90° counterclockwise, and the locking block (12) rotates to the locking area on the side of the slider (5) to lock the slider (5), and at the same time, the locking switch (7) disconnects the working power supply, and the door (15) is unlocked and can be opened.

[0027] Based on any of the above technical solutions, the following further optimization is made: When the PLC controller (16) controls the handcart to move in, if the output contact Y1 (controlling the motor to move forward) sends a signal within 2 seconds and X1 (the input signal of the test position on the monitoring platform 8) does not change from 0 to 1, or if X1 does not change position within 8 seconds, the PLC controller (16) controls Y1 to stop outputting and the motor (6) stops rotating; when the handcart is controlled to move out, if the output contact Y0 (controlling the motor to move backward) and Y1 send a signal within 2 seconds and X2 (the input signal of the working position on the monitoring platform 8) does not change from 0 to 1, or if X2 does not change position within 8 seconds, the PLC controller (16) controls Y0 and Y1 to stop outputting and the motor (6) stops rotating.

[0028] Based on any of the above technical solutions, the following further optimizations are made: the PLC controller (16) can control up to 11 handcarts; the power switching relay (21) can realize the control power switching: when controlling the incoming circuit breaker electric handcart (DC110V), the power switching relay (21) automatically switches to 110V power; when controlling the outgoing handcart (DC24V), the power switching relay (21) automatically switches to 24V power; the platforms (8) of multiple electric push-pull mechanisms are at the same height, and multiple handcarts are arranged side by side in the horizontal direction in the housing, and the movement trajectory of each handcart along the platform (8) is parallel to each other.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention fully utilizes the internal space of the equipment by installing the electric push-pull mechanism inside the front door flange and adopting a compact transmission structure of platform-slider-zigzag plate and a multi-cart horizontal parallel arrangement design. At the same time, the separate assembly method of the electric push-pull mechanism and the 400A mechanism improves the versatility of the components and adapts to the assembly requirements of different specifications of carts.

[0030] 2. This invention utilizes the closed-loop control logic of a PLC controller, combined with multiple safety mechanisms such as initial condition verification, motor overcurrent protection, and multi-cart start interlocking. It also incorporates a mechanical and electrical dual interlocking design with interlocking shaft linkage, providing dual protection for cart operation safety from both the control process and mechanical structure perspectives, thus avoiding the risks of misoperation and equipment failure.

[0031] 3. This invention adopts a design in which multiple vehicles share a single drive unit, which reduces redundant configuration of hardware such as rectifier units and forward / reverse relays, thereby reducing system costs; at the same time, the separate structure and the detection logic of automatic return to position upon power-on simplify the component disassembly and assembly and fault diagnosis process, and improve the convenience of operation and maintenance.

[0032] 4. This invention achieves adaptive switching of DC110V / DC24V voltage through a power switching relay, adapting to the different voltage requirements of the incoming circuit breaker and the feeder truck. The PLC controller supports the control of up to 11 trucks. With a highly consistent platform and parallel movement trajectory design, the number of trucks can be flexibly expanded to meet the application needs of different scale power supply systems. Attached Figure Description

[0033] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or components are generally identified by similar reference numerals. In the drawings, the elements or components are not necessarily drawn to scale.

[0034] Figure 1 This is a schematic diagram of the starting control point state of the present invention.

[0035] Figure 2 This is a schematic diagram of the combined power supply handcart control program of the present invention, which monitors the position of handcart #1.

[0036] Figure 3 This is a schematic diagram of the motor not outputting a 2S reset M49 according to the present invention.

[0037] Figure 4 This is a schematic diagram of the control program of the 1# handcart reaching the test position and M90 sending a signal to the 2# handcart.

[0038] Figure 5 This is a schematic diagram of signal transmission #2 of the present invention.

[0039] Figure 6 This is a schematic diagram of the operation of the No. 1 handcart of the present invention.

[0040] Figure 7 This is a schematic diagram of the handcart structure of the present invention.

[0041] Figure 8 This is a three-dimensional structural diagram of the electric push-pull mechanism of the present invention.

[0042] Figure 9 This is a top view of the electric push-pull mechanism of the present invention.

[0043] Figure 10 This is a schematic diagram of the door structure of the present invention.

[0044] Figure 11 This is a schematic diagram of the connection relationship of the PLC controller of the present invention.

[0045] In the diagram: 1. Pin hole; 2. Contact; 3. Guide pin; 4. Lead screw; 5. Slider; 6. Motor; 7. Locking switch; 8. Platform; 9. Z-shaped plate; 10. Locking square hole; 11. Threaded hole; 12. Locking block; 14. Locking shaft; 15. Door body; 16. PLC controller; 17. Protective current transmitter unit; 18. Rectifier unit; 19. Fuse; 20. Current transformer; 21. Power switching relay; 22. Forward and reverse relay; 23. AC127V power interface; 24. AC24V power interface; 25. Multi-channel drive output unit. Detailed Implementation

[0046] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are therefore merely examples and should not be used to limit the scope of protection of the present invention. The specific structure of the present invention is as follows: Figures 1-11 As shown in the image.

[0047] Example 1: A control method for a centralized control system of a combined power supply trolley, comprising the following steps: S1: Constructing a control architecture, the architecture comprising multiple low-voltage circuit breaker trolleys, multiple electric push-pull mechanisms corresponding one-to-one with the trolleys, a PLC controller (16) and a drive unit; each electric push-pull mechanism is installed in the front door flange, and a lead screw (4) extending along the length of the platform is provided above its horizontally arranged platform (8), the lead screw (4) is threadedly engaged with a slider (5), a Z-shaped plate (9) is fixedly connected to the upper surface of the slider (5), and a low-voltage circuit breaker is connected above the Z-shaped plate (9). The mechanism of the handcart (the bottom of the mechanism is attached to the upper surface of the platform 8); the electric push-pull mechanism housing is equipped with a motor (6) at the end, and the motor (6) is connected to the lead screw (4) for transmission; the drive unit includes a protection current transmitter unit (17), a rectifier unit (18), a fuse (19), a current transformer (20), a power switching relay (21), a forward and reverse relay (22), an AC127V power interface (23), an AC24V power interface (24) and a multi-channel drive output unit (25), and the drive unit is shared by multiple handcarts, and only one handcart is controlled at the same time.

[0048] It should be noted that the working principle of this step is as follows: A one-to-one design between the handcart and the electric push-pull mechanism ensures that the power of each handcart is independently controllable, while the shared drive unit design reduces hardware redundancy. The positional relationship of each component (horizontal platform arrangement, lead screw extending along the platform length, slider and U-shaped plate fixed vertically, and mechanism attached to the platform) forms a vertical power transmission chain of motor-lead screw-slider-U-shaped plate-mechanism. Utilizing the high precision characteristics of threaded transmission and the guiding effect of the platform, the smooth movement of the handcart is ensured. Its advantages are: the front flange installation method makes full use of existing space, reducing the overall size of the equipment; multiple handcarts sharing a drive unit reduces system cost and failure rate; and the single-unit control logic avoids interference from multiple handcart movements at the same time. Its function is to provide the structural foundation and power support for the subsequent handcart's rocking in and rocking out control, ensuring the rationality and reliability of the control architecture.

[0049] S2: The host computer sends the handcart in / out command to the PLC controller (16) via communication. The PLC controller (16) first determines whether the initial operating conditions of the corresponding handcart are met.

[0050] It should be noted that the working principle of this step is as follows: the host computer acts as a human-machine interface terminal, transmitting control commands to the PLC controller via communication protocols (such as Modbus, TCP / IP, etc.). The PLC, as the core control unit, first performs logical judgments on the critical states of the pre-controlled trolley to prevent unauthorized operations. Its advantages are: command transmission uses communication methods, resulting in simple wiring, flexible control, and the ability to operate remotely; the initial condition judgment step sets safety thresholds for trolley operation, mitigating risks at the source. Its function is to establish a control flow of command issuance and status verification, ensuring that the trolley only starts and operates under safe conditions, thus protecting equipment and personnel safety.

[0051] S3: If the initial conditions are met, the PLC controller (16) controls the motor (6) of the corresponding handcart to rotate forward / reverse through the output contacts. The motor (6) drives the lead screw (4) to rotate, and the slider (5) moves back and forth along the platform (8), thereby driving the zigzag plate (9) and the handcart mechanism above to move back and forth along the platform (8) synchronously.

[0052] It should be noted that the working principle of this step is as follows: the PLC output contacts control the on / off state of the forward and reverse relays to achieve forward and reverse switching of the motor; the motor power is transmitted to the lead screw through coaxial transmission (or coupling). When the lead screw rotates, the meshing action of the thread and the slider converts the rotational motion into the linear motion of the slider. The slider drives the mechanism (cart) to move synchronously along the platform through the Z-plate. The platform provides a support surface and guide trajectory for the slider and the mechanism. Its advantages are: the threaded transmission has the characteristics of high precision and high stability, which can accurately control the movement distance of the cart; the synchronous movement design of each component ensures lossless power transmission and smooth, jam-free movement of the cart. Its function is to achieve precise switching of the cart between the test position and the working position, providing equipment position assurance for the normal power supply or maintenance of the power system.

[0053] S4: When the motor (6) is running, the current transformer (20) installed on the motor power supply line collects the motor current and transmits it to the A0 interface of the PLC controller (16) through the protection current transmitter unit (17). When the motor current value obtained by the PLC calculation is greater than 1.3A, the overcurrent protection is triggered.

[0054] It should be noted that the working principle of this step is as follows: A current transformer is connected in series in the motor power supply line, using the principle of electromagnetic induction to convert the large current of the motor into a small current signal; the protection current transmitter unit converts this small current signal into a standard analog signal (such as 4-20mA) that can be recognized by the PLC, and transmits it to the PLC's A0 analog input interface. The PLC calculates the actual motor current value through its internal program and compares it with a preset 1.3A protection threshold. If the threshold is exceeded, the protection logic is triggered. Its advantages are: high accuracy and fast response in the current acquisition and signal conversion process, allowing for real-time monitoring of the motor's operating status; the 1.3A threshold is set based on the motor's rated load and the mechanism's jamming limit load, effectively distinguishing between normal operating current and fault current. Its function is to prevent the motor from burning out due to excessive current caused by overload, mechanism jamming, etc., extending the service life of the motor and the electric push-pull mechanism, and improving the safety of system operation.

[0055] S5: By monitoring the motor current of the currently running handcart, the motor starting circuit of other handcarts is blocked.

[0056] It should be noted that the working principle of this step is as follows: The PLC determines that the trolley is in operation by detecting the current signal of the currently running trolley motor (if there is a running current greater than 0). Then, it disconnects the control signal channel of other trolley motor starting circuits through the contacts of the internal auxiliary relay M100, preventing the start commands of other trolleys from being transmitted to the drive unit. Its advantages are: the current signal-based interlocking logic responds quickly and accurately, requiring no additional status detection sensors; the interlocking mechanism is protected by both hardware and software, ensuring high reliability. Its function is to strictly enforce the rule of controlling only one trolley at a time, avoiding mechanical interference and circuit conflicts caused by multiple trolleys moving simultaneously, thus ensuring the orderly operation of the system.

[0057] S6: After the system is powered on, the PLC controller (16) monitors the position of each handcart and controls the motor (6) to reverse and push the handcart that is in the middle position above the platform (8) when it is not working or not being tested to the test position.

[0058] It should be noted that the working principle of this step is as follows: After the system is powered on, the PLC reads the feedback signals from each trolley position sensor to determine whether the trolley is in the intermediate position (neither the test position nor the working position). If it is determined to be in the intermediate position, the PLC outputs a reverse control signal to the corresponding motor, which drives the trolley to move towards the test position until the position sensor sends a feedback signal indicating that it is in the correct position. Its advantages are: the automatic return design upon power-on requires no manual intervention, improving the system's automation level; the test position is the safe initial position of the trolley, avoiding the risk of accidental start-up of a trolley in the intermediate position. Its purpose is to standardize the initial state of the trolleys after system power-on, facilitating the determination of the state when the host computer issues control commands, while also preventing trolleys in the intermediate position from affecting the operation of other equipment, thus improving the overall reliability of the system.

[0059] Based on any of the above technical solutions, the following further optimization is made: the initial conditions for the handcart to be jacked in step S2 are X0=1 (circuit breaker not closed), X1=0 (handcart in the test position above platform 8), and X2=1 (handcart not in the working position above platform 8); the jacking in control process in step S3 is as follows: the output contact Y1 of the PLC controller (16) controls the motor (6) to rotate in the forward direction, and the handcart moves along platform 8 to the working position; if X1 does not change from 0 to 1 within 2 seconds of Y1 issuing the signal (handcart has not left the test position), Y1 stops outputting and the motor (6) stops rotating; after X1 changes position normally, the motor (6) continues to run for about 5 seconds, and when X2 changes from 1 to 0 (handcart reaches the working position), the motor (6) stops rotating; if X1 does not change position within 8 seconds, it is determined to be a handcart fault, and the motor (6) stops rotating; where X is the PLC input signal address identifier, corresponding to the feedback signal of the handcart position sensor (monitoring the handcart position on platform 8) and the circuit breaker status switch.

[0060] It should be noted that the working principle of this optimized scheme is as follows: the three signals (X0, X1, X2) for the initial conditions of the trolley input correspond to the key safety indicators of the circuit breaker status and the trolley position, respectively. Only when all three conditions are met simultaneously will the PLC allow the trolley input action to be initiated, avoiding violations such as trolley input under load or repeated trolley input. The 2-second position change monitoring during the control process is used to determine whether the trolley responds to the start command in a timely manner. The 5-second continuous operation is based on the normal movement time of the trolley from the test position to the working position. The 8-second fault determination is for extreme timeout protection, forming a closed-loop control of start response - continuous operation - stop at position - timeout fault. Its advantages are: multiple verifications of the initial conditions and multi-node monitoring during the process greatly improve the safety and accuracy of the trolley input control; the X and Y address identifiers adopt the PLC industry standard, which is highly universal and easy to debug and maintain. Its function is to standardize the trolley input operation process, avoid equipment damage caused by misoperation, mechanism jamming, etc., and ensure that the trolley accurately and safely reaches the working position.

[0061] Based on any of the above technical solutions, the following further optimization is made: the initial conditions for the handcart to be moved out in step S2 are X0=1 (circuit breaker not closed), X1=1 (handcart not in the test position above platform 8), and X2=0 (handcart in the working position above platform 8); the control process for moving out in step S3 is as follows: the output contact Y1 of the PLC controller (16) controls the motor (6) to rotate, and at the same time Y0 controls the motor (6) to reverse, and the handcart moves along platform 8 to the test position; if X2 does not change from 0 to 1 within 2 seconds of Y0 and Y1 issuing signals (the handcart has not left the working position), Y0 and Y1 stop outputting and the motor (6) stops rotating; after X2 changes position normally, the motor (6) continues to run for about 5 seconds, and when X1 changes from 1 to 0 (the handcart reaches the test position), the motor (6) stops rotating; if X2 does not change position within 8 seconds, it is determined that the handcart is faulty and the motor (6) stops rotating.

[0062] It should be noted that the working principle of this optimized scheme is as follows: the initial conditions for rollout and the conditions for rollin are symmetrically designed to ensure that the trolley is only started for rollout under safe conditions such as when the circuit breaker is open, in the working position, and not in the test position; motor reversal is achieved through the coordinated control of Y0 and Y1 contacts to ensure accurate reversal direction; the logic of 2-second position change monitoring, 5-second continuous operation, and 8-second fault judgment is consistent with the rollin control, maintaining the uniformity of the control process; the reverse switching of position signals (X2 from 0 to 1, X1 from 1 to 0) corresponds to the movement trajectory of the trolley from the working position to the test position. Its advantages are: using the same time threshold and judgment logic as the rollin control reduces the complexity of the system program and facilitates maintenance; the strict limitation of the initial conditions avoids risks such as rollout under load or rollout before reaching the correct position. Its function is to standardize the operation process of trolley rollout, ensuring that the trolley safely and accurately returns to the test position from the working position, providing safe conditions for equipment inspection and maintenance.

[0063] Based on any of the above technical solutions, the following optimization is made: The specific process of overcurrent protection in step S4 is as follows: When the handcart is running in the forward direction (moving along the platform 8 to the working position), the PLC controller (16) first stops the motor (6) from running in the forward direction, and then controls the motor (6) to reverse, driving the handcart to return to the test position along the platform 8; when the handcart is running in the reverse direction (moving along the platform 8 to the test position), the PLC controller (16) directly stops the motor (6) from running in the reverse direction, and the handcart stays at the current position of the platform 8 without returning to the working position.

[0064] It should be noted that the working principle of this optimization scheme is as follows: Different protection strategies are designed based on the different directions of the trolley's movement. Overcurrent during forward movement (swinging in) is often caused by mechanical jamming or path obstruction. In this case, controlling the motor to reverse and return to the test position (safe initial position) avoids subsequent risks caused by the trolley being stuck in the middle position. Overcurrent during reverse movement (swinging out) occurs because the trolley itself is moving towards the safe area; directly stopping the machine prevents it from returning to the working position (dangerous position) and facilitates troubleshooting. Its advantages are: the protection strategy is highly targeted, balancing safety and practicality, avoiding secondary risks caused by a one-size-fits-all protection approach; both the retraction and stopping actions are automatically controlled by the PLC, with rapid response and no need for manual intervention. Its function is to take the most appropriate emergency measures when a motor overcurrent fault occurs, minimizing fault losses and ensuring the safety of equipment and personnel.

[0065] Based on any of the above technical solutions, the following optimization is made: the process of locking the starting circuit of other handcart motors in step S5 is as follows: after the motor (6) of any handcart starts, the current of the motor is detected by the D8030 current detection register inside the PLC, and then the starting circuit of the motor of other handcarts is locked by the contact of the M100 auxiliary relay inside the PLC; after locking, the starting control point of other handcarts cannot output a signal to control the corresponding motor (6) drive output, ensuring that only one handcart moves on the platform 8 at the same time.

[0066] It should be noted that the working principle of this optimization scheme is as follows: D8030 is a dedicated current detection register inside the PLC, which can store the current data of the currently running motor in real time. When the current value is greater than 0, it is determined that the motor is in running state, triggering the M100 auxiliary relay to act. The normally open contact of M100 is connected in series in the control channel of other handcart motor starting circuits. After the relay is activated, the contact opens, cutting off the starting control signal of other handcarts, realizing circuit interlocking. Its advantages are: using the PLC's internal register and relay to achieve interlocking, no additional hardware equipment is required, reducing costs; the interlocking logic is directly related to current detection, the judgment is accurate, and the response time is short (millisecond level); the interlocking only applies to the starting circuit and does not affect other status monitoring functions, resulting in high system flexibility. Its function is to enforce the rule that only one handcart runs at the same time from the circuit level, completely eliminating problems such as mechanical collisions and circuit overloads caused by multiple handcarts starting simultaneously, and improving the stability and safety of system operation.

[0067] Based on any of the above technical solutions, the following optimization is made: The process of monitoring the position of the handcart in step S6 is as follows: During the first scanning cycle after the system is powered on, the M8003 initial pulse relay inside the PLC sends a holding signal to the M49 auxiliary relay, and the PLC controller (16) monitors the position of each handcart on the platform 8; If a handcart is in the middle position above the platform 8, the handcart motor (6) is triggered to rotate in the opposite direction and push the handcart to the test position; After the handcart is in position, the signal is transmitted to the next handcart detection program through the M90 ​​position signal relay inside the PLC; If the handcart fails to push back, the signal is transmitted to the next handcart detection program through the T61 delay timer inside the PLC and the current handcart detection is stopped; After all handcarts are monitored, the T90 delay timer inside the PLC sends a stop signal after 3 seconds, and the T50 delay timer stops the detection program after 2 seconds.

[0068] It should be noted that the working principle of this optimized solution is as follows: M8003 is an instantaneous pulse relay for the first scan cycle after PLC power-on, used to trigger the start of the power-on detection program; M49 auxiliary relay is used to maintain the running state of the detection program; the PLC adopts a one-by-one handcart detection mode to avoid signal conflicts caused by simultaneous detection of multiple handcarts; M90 position signal relay is used to transmit the position status, realizing the sequential execution of the detection program; T61 delay timer is used to determine the backtracking fault (set backtracking timeout time), skipping the current handcart in case of a fault to avoid affecting the detection of other handcarts; T90 and T50 are used for the overall stop control of the detection program to ensure the orderly completion of the program. Its advantages are: it uses dedicated relays and timers inside the PLC to achieve automated control of the detection process, with rigorous logic and no need for manual intervention; the one-by-one handcart detection and fault isolation design ensure that the detection process is not stuck or interrupted; the time parameters can be adjusted according to the actual equipment, making it highly versatile. Its function is to automatically calibrate and return all the positions of the handcarts after the system is powered on, ensuring that the initial state of each handcart is consistent, laying the foundation for the execution of subsequent control commands, and at the same time quickly locating faulty handcarts, improving the efficiency of system maintenance.

[0069] Example 2: Compared with Example 1, this example also includes the following technical features: The present invention also includes a centralized control system for combined power supply trolleys, comprising: multiple low-voltage circuit breaker trolleys, multiple electric push-pull mechanisms corresponding to each trolley, a PLC controller (16) and a drive unit.

[0070] Each low-voltage circuit breaker trolley includes a core, the bottom of which is attached to the upper surface of the platform (8) of the electric push-pull mechanism, the side of the core is provided with a pin hole (1) and a guide pin (3), and the front end of the core is provided with a contact (2).

[0071] Each electric push-pull mechanism is installed inside the front door flange and includes a horizontally arranged platform (8), a lead screw (4) extending along the length of the platform (8), a slider (5) sleeved on the lead screw (4) and with its bottom attached to the upper surface of the platform (8), a zigzag plate (9) fixed on the upper surface of the slider (5), a motor (6) fixed to the end of the electric push-pull mechanism housing and connected to the lead screw (4), a locking shaft (14) horizontally passing through the side of the electric push-pull mechanism housing, a locking block (12) sleeved on the locking shaft (14) near the end of the slider (5), and a locking switch (7) set on the side of the electric push-pull mechanism housing and linked with the locking shaft (14); the zigzag plate (9) has a locking square hole (10) and a screw hole (11), which respectively cooperate with the guide pin (3) and pin hole (1) of the mechanism.

[0072] The drive unit includes a protection current transmitter (17), a rectifier (18), a fuse (19), a current transformer (20) installed on the power supply lines of each motor (6), a power switching relay (21), a forward and reverse relay (22), an AC127V power interface (23), an AC24V power interface (24), and a multi-drive output unit (25) integrated in the control box. The control box is fixed on the outside of the electric push-pull mechanism housing, and the drive unit is shared by multiple vehicles.

[0073] The PLC controller (16) is connected to the host computer. Its A0 interface is electrically connected to the protection current transmitter unit (17), and its output contacts are electrically connected to the forward and reverse relay (22). The system is set to 1.3A as the motor protection threshold. The locking shaft (14) is linked to the equipment door (15) at the end away from the slider (5).

[0074] It should be noted that the working principle of this system is as follows: The system uses a PLC controller as its core, providing power and protection to the motors of each trolley through a drive unit. The electric push-pull mechanism provides movement support and transmission for the trolleys. The low-voltage circuit breaker trolleys achieve position switching through the cooperation of the mechanism and the push-pull mechanism. The positional relationship of each component (mechanism fitting against the platform, slider and zigzag plate fixed vertically, lead screw extending along the platform, and locking shaft horizontally passing through the housing) ensures smooth power transmission and accurate positioning. The integrated design of the drive unit reduces wiring complexity, and the shared design for multiple trolleys lowers hardware costs. Its advantages are: compact structural layout, efficient use of space with the front flange installation, reducing equipment size; tight fit between components, high transmission efficiency, and high positioning accuracy; high degree of integration of the drive unit, low failure rate, and easy maintenance; remote control via PLC communication with the host computer, making operation convenient. Its function is to provide a hardware carrier for the control method of Example 1, achieving safe, accurate, and efficient control of multiple low-voltage circuit breaker trolleys through the coordinated work of various components, meeting the power supply needs of the power system.

[0075] Based on any of the above technical solutions, the following further optimizations are made: the electric push-pull mechanism and the 400A movement adopt a separate design; the guide pin (3) of the movement is horizontally inserted into the locking square hole (10) of the zig plate (9) to achieve radial positioning of the movement and the zig plate (9); the pin hole (1) of the movement and the thread hole (11) of the zig plate (9) are coaxially corresponding and fixed by M8 bolts so that when the zig plate (9) moves, it can drive the movement to move synchronously back and forth along the platform (8).

[0076] It should be noted that the working principle of this optimized solution is as follows: the separate design allows the movement mechanism and the electric push-pull mechanism to be manufactured, transported, and maintained separately. During assembly, radial positioning is achieved through the cooperation of guide pins and locking square holes (limiting the left-right and up-down swaying of the movement mechanism and the zigzag plate), and axial fixing is achieved through M8 bolts passing through pin holes and threaded holes (limiting front-back displacement), forming a dual connection structure of positioning and fixing to ensure synchronous movement of both. Its advantages are: the separate design improves the equipment's versatility and ease of maintenance; the same electric push-pull mechanism can be adapted to the same specification 400A movement mechanism; the cooperation of the guide pins and locking square holes ensures precise positioning; the bolt fixing connection is firm; there is no relative displacement in power transmission, reducing mechanical wear; the connection structure is simple and reliable, assembly efficiency is high, and subsequent disassembly and maintenance are convenient. Its function is to ensure the connection stability and motion synchronization between the movement mechanism and the electric push-pull mechanism, ensuring that the motor power can be accurately transmitted to the movement mechanism, achieving smooth movement of the handcart, while improving the equipment's ease of maintenance and versatility.

[0077] Based on any of the above technical solutions, the following further optimization is made: the connection relationship of each component in the drive unit is as follows: the output terminals of AC127V power interface (23) and AC24V power interface (24) are connected in series with the input terminal of fuse (19), the output terminal of fuse (19) is connected to the input terminal of rectifier unit (18); the output terminal of rectifier unit (18) is connected to the input terminal of power switching relay (21), the output terminal of power switching relay (21) is connected to the power terminal of forward and reverse relay (22); the output terminal of forward and reverse relay (22) is connected to the input terminal of multi-channel drive output unit (25), the output terminal of multi-channel drive output unit (25) is connected to the motor (6) of each handcart respectively; the output terminal of current transformer (20) is connected to the input terminal of protection current transmitter unit (17), the output terminal of protection current transmitter unit (17) is connected to the A0 interface of PLC controller (16).

[0078] It should be noted that the working principle of this optimized solution is as follows: the power interface provides dual voltage inputs to adapt to different power supply requirements; a fuse is connected in series at the power input terminal to achieve overcurrent protection for the entire drive unit, preventing damage to downstream components due to excessive current; the rectifier unit converts AC power to DC power to power DC components such as relays; the power switching relay switches the output voltage (DC110V / DC24V) according to control requirements to adapt to different types of handcart motors; the forward and reverse relay controls the switching of the positive and negative terminals of the motor power supply to achieve forward and reverse rotation of the motor; the multi-channel drive output unit realizes the corresponding connection between a single drive circuit and multiple motors, and controls the channel on and off through PLC control; the current transformer and the protective current transmitter unit form a current detection loop to provide signals for overcurrent protection. Its advantages are: clear circuit connection logic, clear functional partitioning, and comprehensive protection mechanisms (overcurrent, voltage adaptation); the multi-channel drive output design enables shared drive units, reducing hardware redundancy; the series / parallel connection of each component complies with electrical design specifications, ensuring high stability and facilitating debugging and troubleshooting. Its function is to build a stable, safe, and universal drive circuit, provide precise power control and protection for the motor, ensure orderly operation when multiple vehicles share the drive unit, and adapt to vehicles with different voltage specifications to improve system versatility.

[0079] Based on any of the above technical solutions, the following further optimization is made: The locking logic of the locking shaft (14) is as follows: When the system is running normally, the locking shaft (14) drives the locking block (12) to rotate 90° clockwise, so that the locking block (12) is disengaged from the locking area on the side of the slider (5), and at the same time, the locking switch (7) rotates 90° clockwise to conduct and connect the control power supply; after the slider (5) drives the handcart away from the test position on the platform (8), the locking block (12) cannot rotate counterclockwise, and the locking shaft (14) locks the door (15) in conjunction with the locking. When the slider (5) drives the handcart back to the test position on the platform (8), the locking shaft (14) rotates 90° counterclockwise, and the locking block (12) rotates to the locking area on the side of the slider (5) to lock the slider (5), and at the same time, the locking switch (7) disconnects the working power supply, and the door (15) is unlocked and can be opened.

[0080] It should be noted that the working principle of this optimized scheme is as follows: the locking shaft controls both the locking block and the locking switch simultaneously through a mechanical linkage structure, forming a dual guarantee of mechanical and electrical interlocking. When the trolley is not running, the locking block locks the slider to prevent accidental movement of the trolley, and the locking switch opens, cutting off the control power. Before the trolley starts, the locking shaft rotates to release the slider and connect the power, ensuring that it can only be started after unlocking. When the trolley is running, the locking block cannot rotate in the reverse direction due to the slider's position limitation, locking the door to prevent personnel from accidentally opening the door and causing danger. After the trolley returns to its original position, the locking shaft rotates in the reverse direction, relocks the slider, cuts off the power, and unlocks the door. Its advantages are: the mechanical and electrical interlocking linkage design provides a high safety factor and completely eliminates the risk of misoperation; the locking logic is strongly correlated with the trolley position, requiring no additional control signals and ensuring high reliability; the mechanical structure is simple and durable, with low maintenance costs. Its function is to ensure the safety of personnel and equipment during trolley operation, prevent dangerous situations such as accidental movement of the trolley and accidental opening of the door, and further enhance system safety by cutting off the power through electrical interlocking.

[0081] Based on any of the above technical solutions, the following further optimization is made: When the PLC controller (16) controls the handcart to move in, if the output contact Y1 (controlling the motor to move forward) sends a signal within 2 seconds and X1 (the input signal of the test position on the monitoring platform 8) does not change from 0 to 1, or if X1 does not change position within 8 seconds, the PLC controller (16) controls Y1 to stop outputting and the motor (6) stops rotating; when the handcart is controlled to move out, if the output contact Y0 (controlling the motor to move backward) and Y1 send a signal within 2 seconds and X2 (the input signal of the working position on the monitoring platform 8) does not change from 0 to 1, or if X2 does not change position within 8 seconds, the PLC controller (16) controls Y0 and Y1 to stop outputting and the motor (6) stops rotating.

[0082] It should be noted that the working principle of this optimized solution is as follows: After the PLC outputs a control signal, it monitors the change in position signal to determine whether the trolley is responding normally. 2 seconds is the maximum response time for the trolley; if there is no change, it indicates the trolley has not started or the mechanism is stuck, requiring immediate shutdown to prevent motor burnout. 8 seconds is the maximum time for position signal change; if no change occurs within this time, it is considered a serious fault, requiring shutdown for investigation. Its advantages are: closed-loop monitoring of control signal output and position signal feedback enables rapid fault identification and response; the scientifically set time threshold avoids misjudgment and timely loss mitigation; automatic shutdown in case of fault, requiring no manual intervention, improving system autonomy and safety. Its function is to promptly detect starting and jamming faults during the trolley's in / out process, preventing the fault from escalating to serious consequences such as motor burnout and mechanism damage, while providing clear fault indications for maintenance personnel, improving maintenance efficiency.

[0083] Based on any of the above technical solutions, the following further optimizations are made: the PLC controller (16) can control up to 11 handcarts; the power switching relay (21) can realize the control power switching: when controlling the incoming circuit breaker electric handcart (DC110V), the power switching relay (21) automatically switches to 110V power; when controlling the outgoing handcart (DC24V), the power switching relay (21) automatically switches to 24V power; the platforms (8) of multiple electric push-pull mechanisms are at the same height, and multiple handcarts are arranged side by side in the horizontal direction in the housing, and the movement trajectory of each handcart along the platform (8) is parallel to each other.

[0084] It should be noted that the working principle of this optimized solution is as follows: the PLC controller's input / output channels support the transmission of control and status signals for up to 11 handcarts, meeting the needs of multiple handcarts in medium to large-scale power supply systems; the power switching relay automatically identifies the handcart type (incoming / outgoing) through the PLC's control signals and switches the corresponding output voltage to adapt to the voltage requirements of different motors; the platform is arranged at a consistent height and horizontally alongside the handcarts, ensuring that the movement trajectories of each handcart are parallel and without mechanical interference. Its advantages are: the control capacity of 11 handcarts is suitable for most industrial scenarios, offering strong versatility; the automatic power switching design eliminates the need for manual adjustment, improving operational convenience; the parallel arrangement design fully utilizes the housing space, reducing the equipment's footprint while avoiding interference from multiple handcart movements. Its function is to expand the system's applicability, adapting to handcarts with different voltage specifications and power supply systems of different sizes, while optimizing equipment layout, improving space utilization and operational stability.

[0085] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention. For those skilled in the art, any alternative improvements or transformations made to the implementation of the present invention fall within the protection scope of the present invention.

[0086] Any aspects of this invention not described in detail are well-known to those skilled in the art.

Claims

1. A control method for a centralized control system of a combined power supply trolley, characterized in that, Includes the following steps: S1: Construct a control architecture, which includes multiple low-voltage circuit breaker trolleys, multiple electric push-pull mechanisms corresponding to each trolley, a PLC controller (16), and a drive unit; each electric push-pull mechanism is installed inside the front door flange, and a lead screw (4) extending along the length of the platform is provided above its horizontally arranged platform (8). The lead screw (4) is threadedly engaged with a slider (5). A Z-shaped plate (9) is fixedly connected to the upper surface of the slider (5). The mechanism of the low-voltage circuit breaker trolley is connected above the Z-shaped plate (9), and the bottom of the mechanism is attached to the platform ( 8) Upper surface; The end of the housing of the electric push-pull mechanism is provided with a motor (6), and the motor (6) is connected to the lead screw (4) for transmission; The drive unit includes a protection current transmitter unit (17), a rectifier unit (18), a fuse (19), a current transformer (20), a power switching relay (21), a forward and reverse relay (22), an AC127V power interface (23), an AC24V power interface (24), and a multi-channel drive output unit (25), and the drive unit is shared by multiple handcarts, and only one handcart is controlled at the same time; S2: The host computer sends the handcart in / out command to the PLC controller (16) via communication. The PLC controller (16) first determines whether the initial running conditions of the corresponding handcart are met. S3: If the initial conditions are met, the PLC controller (16) controls the motor (6) of the corresponding handcart to rotate forward / reverse through the output contacts. The motor (6) drives the lead screw (4) to rotate, and the slider (5) moves back and forth along the platform (8), thereby driving the zigzag plate (9) and the mechanism of the handcart above to move back and forth along the platform (8) in sync. S4: When the motor (6) is running, the current transformer (20) installed on the power supply line of the motor (6) collects the motor current and transmits it to the A0 interface of the PLC controller (16) through the protection current transmitter unit (17). When the motor current value calculated by the PLC controller (16) is greater than 1.3A, the overcurrent protection is triggered. S5: By monitoring the motor current of the currently running handcart, the motor starting circuit of other handcarts is blocked; S6: After the system is powered on, the PLC controller (16) monitors the position of each handcart and controls the motor (6) to reverse and push the handcart that is in the middle position above the platform (8) when it is not working or not being tested to the test position. In step S2, the initial conditions for the handcart to be driven in are X0=1, X0=1 indicates that the circuit breaker is not closed, X1=0, X1=0 indicates that the handcart is in the test position above the platform (8), and X2=1, X2=1 indicates that the handcart is not in the working position above the platform (8). The control process in step S3 is as follows: the output contact Y1 of the PLC controller (16) controls the motor (6) to rotate in the forward direction, and the handcart moves along the platform (8) to the working position; if X1 does not change from 0 to 1 within 2 seconds after Y1 sends a signal, it means that the handcart has not left the test position, Y1 stops outputting and the motor (6) stops rotating; after X1 changes position normally, the motor (6) continues to run for about 5 seconds, and when X2 changes from 1 to 0, it means that the handcart has reached the working position and the motor (6) stops rotating; if X1 does not change position within 8 seconds, it is determined that the handcart is faulty and the motor (6) stops rotating; where X is the input signal address identifier of the PLC controller (16), corresponding to the handcart position on the platform (8) monitored by the handcart position sensor and the feedback signal of the circuit breaker status switch.

2. The control method according to claim 1, characterized in that, In step S2, the initial conditions for the handcart to be moved out are X0=1, X0=1 indicates that the circuit breaker is not closed, X1=1, X1=1 indicates that the handcart is not in the test position above the platform (8), and X2=0, X2=0 indicates that the handcart is in the working position above the platform (8). The control process in step S3 is as follows: the output contact Y1 of the PLC controller (16) controls the motor (6) to rotate, and at the same time Y0 controls the motor (6) to reverse. The handcart moves along the platform (8) to the test position. If X2 does not change from 0 to 1 within 2 seconds after Y0 and Y1 send signals, it means that the handcart has not left the working position. Y0 and Y1 stop outputting and the motor (6) stops rotating. After X2 changes position normally, the motor (6) continues to run for about 5 seconds. When X1 changes from 1 to 0, it means that the handcart has reached the test position and the motor (6) stops rotating. If X2 does not change position within 8 seconds, it is determined that the handcart is faulty and the motor (6) stops rotating.

3. The control method according to claim 1, characterized in that, The specific process of overcurrent protection in step S4 is as follows: When the handcart is running in the forward direction, it moves along the platform (8) to the working position. The PLC controller (16) first stops the motor (6) from running in the forward direction, and then controls the motor (6) to reverse, driving the handcart to return to the test position along the platform (8); when the handcart is running in the reverse direction, it moves along the platform (8) to the test position. The PLC controller (16) directly stops the motor (6) from running in the reverse direction, and the handcart stays at the current position of the platform (8) without returning to the working position.

4. The control method according to claim 1, characterized in that, The process of locking the motor starting circuit of other handcarts in step S5 is as follows: After the motor (6) of any handcart starts, the motor current is detected by the D8030 current detection register inside the PLC controller (16), and then the motor starting circuit of other handcarts is locked by the contact of the M100 auxiliary relay inside the PLC controller (16). After locking, the starting control point of other handcarts cannot output a signal to control the corresponding motor (6) drive output, ensuring that only one handcart moves on the platform (8) at the same time.

5. The control method according to claim 1, characterized in that, The process of monitoring the position of the handcart in step S6 is as follows: During the first scan cycle after the system is powered on, the M8003 initial pulse relay inside the PLC controller (16) sends a holding signal to the M49 auxiliary relay. The PLC controller (16) controls the position of the handcart monitoring platform (8) one by one. If a handcart is in the middle position above the platform (8), the motor (6) of the handcart is triggered to rotate in the opposite direction and push the handcart to the test position. After the handcart is in position, the signal is transmitted to the next handcart detection program through the M90 ​​position signal relay inside the PLC controller (16). If the handcart fails to push back, the signal is transmitted to the next handcart detection program through the T61 delay timer inside the PLC controller (16) and the current handcart detection is stopped. After all handcarts are monitored, the T90 delay timer inside the PLC controller (16) sends a stop signal after 3 seconds and the T50 delay timer stops the detection program after 2 seconds.

6. A centralized control system for a combined power-fed handcart, characterized in that, It includes multiple low-voltage circuit breaker trolleys, multiple electric push-pull mechanisms corresponding to each trolley, a PLC controller (16) and a drive unit; Each low-voltage circuit breaker trolley includes a core, the bottom of which is attached to the upper surface of the platform (8) of the electric push-pull mechanism, the side of the core is provided with a pin hole (1) and a guide pin (3), and the front end of the core is provided with a contact (2). Each electric push-pull mechanism is installed inside the front door flange and includes a horizontally arranged platform (8), a lead screw (4) extending along the length of the platform (8), a slider (5) sleeved on the lead screw (4) and with its bottom attached to the upper surface of the platform (8), a zigzag plate (9) fixed on the upper surface of the slider (5), a motor (6) fixed to the end of the housing of the electric push-pull mechanism and connected to the lead screw (4), a locking shaft (14) horizontally passing through the side of the housing of the electric push-pull mechanism, a locking block (12) sleeved on the end of the locking shaft (14) near the slider (5), and a locking switch (7) set on the side of the housing of the electric push-pull mechanism and linked with the locking shaft (14); the zigzag plate (9) has a locking square hole (10) and a screw hole (11) which respectively cooperate with the guide pin (3) and pin hole (1) of the mechanism. The drive unit includes a protection current transmitter (17), a rectifier (18), a fuse (19), a current transformer (20) installed on the power supply lines of each motor (6), a power switching relay (21), a forward and reverse relay (22), an AC127V power interface (23), an AC24V power interface (24), and a multi-channel drive output unit (25) integrated in the control box. The control box is fixed on the outside of the housing of the electric push-pull mechanism. The drive unit is shared by multiple handcarts. The PLC controller (16) is connected to the host computer. Its A0 interface is electrically connected to the protection current transmitter unit (17), and its output contacts are electrically connected to the forward and reverse relay (22). The system is set to 1.3A as the motor protection threshold. The locking shaft (14) is linked to the equipment door (15) at the end away from the slider (5).

7. The control system according to claim 6, characterized in that, The electric push-pull mechanism and the 400A movement are designed separately; the guide pin (3) of the movement is horizontally inserted into the locking square hole (10) of the zig plate (9) to achieve radial positioning of the movement and the zig plate (9); the pin hole (1) of the movement and the thread hole (11) of the zig plate (9) are coaxially corresponding and fixed by M8 bolts so that the movement can drive the movement to move synchronously back and forth along the platform (8) when the zig plate (9) moves.

8. The control system according to claim 7, characterized in that, The connection relationship of each component in the drive unit is as follows: the output terminals of AC127V power interface (23) and AC24V power interface (24) are connected in series with the input terminal of fuse (19), and the output terminal of fuse (19) is connected to the input terminal of rectifier unit (18); the output terminal of rectifier unit (18) is connected to the input terminal of power switching relay (21), and the output terminal of power switching relay (21) is connected to the power terminal of forward and reverse relay (22); the output terminal of forward and reverse relay (22) is connected to the input terminal of multi-channel drive output unit (25), and the output terminal of multi-channel drive output unit (25) is connected to the motor (6) of each handcart respectively; the output terminal of current transformer (20) is connected to the input terminal of protection current transmitter unit (17), and the output terminal of protection current transmitter unit (17) is connected to the A0 interface of PLC controller (16).

9. The control system according to claim 8, characterized in that, The locking logic of the locking shaft (14) is as follows: When the system is running normally, the locking shaft (14) drives the locking block (12) to rotate 90° clockwise, so that the locking block (12) is disengaged from the locking area on the side of the slider (5), and at the same time, the locking switch (7) rotates 90° clockwise to conduct and connect the control power supply; after the slider (5) drives the handcart away from the test position on the platform (8), the locking block (12) cannot rotate counterclockwise, and the locking shaft (14) locks the door (15) in conjunction with the locking. When the slider (5) drives the handcart back to the test position on the platform (8), the locking shaft (14) rotates 90° counterclockwise, and the locking block (12) rotates to the locking area on the side of the slider (5) to lock the slider (5), and at the same time, the locking switch (7) disconnects the working power supply, and the door (15) is unlocked and can be opened.

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