Intelligent control system for lifting electromagnetic chuck

Abstract

The intelligent control system comprises a three-phase thyristor rectifier bridge, a sampling unit and a master controller, the input end of the three-phase thyristor rectifier bridge is connected with a three-phase alternating current power supply, and the output end of the three-phase thyristor rectifier bridge is connected with the lifting electromagnetic chuck through a switch S1 and connected with a storage battery pack through a switch S2; and the storage battery pack is connected in series with the lifting electromagnetic chuck through the IGBT power switch Q1. According to the invention, the technical problems of unreliable magnetic retention intervention, uncontrollable magnetic force, logic conflict risk, huge volume, storage battery maintenance deficiency and the like of a traditional discrete system are solved, seamless switching between magnetic retention and excitation is realized, and accurate magnetic force control under all working conditions and intelligent maintenance of a storage battery in a full life cycle can be realized; the device has the advantages of high safety, strong reliability, compact structure, low cost and the like.

Description

Technical Field

[0001] This invention relates to an intelligent control system for lifting electromagnetic chucks, belonging to the field of industrial control technology. Background Technology

[0002] A lifting electromagnetic chuck (also known as a lifting electromagnet or electromagnetic chuck lifting device) is a core component of industrial lifting equipment that utilizes electromagnetic principles to generate a strong suction force for lifting magnetic materials such as steel. It is typically installed on cranes, excavators, or forklifts, replacing traditional slings to achieve efficient and safe material handling, and is widely used in industries such as metallurgy, mining, and factories.

[0003] However, the existing control systems for lifting electromagnetic chucks have the following technical defects:

[0004] First, existing technologies typically employ two independent systems to separately implement the excitation control and power-off magnetization control of the lifting electromagnetic chuck, with the two systems working together via electrical connection or bus communication. This system architecture suffers from unreliable magnetization intervention because the triggering of the magnetization action depends on the reliability of external communication or electrical connection. When there is a risk of signal loss, delay, or logical conflict, it is impossible to ensure 100% magnetization activation during power failure, posing a safety hazard.

[0005] Secondly, the existing magnetization system only applies the battery voltage directly to the electromagnetic chuck, and cannot achieve current regulation. This means that the magnetic force cannot be adjusted according to the material characteristics during the magnetization process. Excessive magnetic force may cause deformation of finished products such as thin steel plates, while insufficient magnetic force may lead to the risk of material falling. Therefore, the traditional magnetization mode can only be used as an emergency measure, and manual assistance is required to promptly lower the material to a safe location, which seriously restricts the level of automated operation.

[0006] Third, the existing discrete systems each contain controllers and power components, which occupy a large overall volume and are difficult to upgrade and modify on the limited space of the crane beam. In addition, the procurement cost of the two discrete systems is also high.

[0007] Fourth, as a key component of the magnetization protection system, the battery pack only works during random power outages and may remain in a fully charged standby state for a long time without a discharge cycle. This usage will shorten the battery pack's lifespan, not only increasing maintenance costs but also posing a safety hazard that the magnetization protection may fail at critical moments. Summary of the Invention

[0008] In view of the above-mentioned problems in the existing technology, the purpose of the present invention is to provide an intelligent control system for lifting electromagnetic chucks that can achieve seamless switching between excitation and magnetization, precise adjustment of magnetic force under all working conditions, and intelligent maintenance of the battery pack throughout its entire life cycle.

[0009] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0010] An intelligent control system for lifting electromagnetic chucks includes:

[0011] The three-phase thyristor rectifier bridge (REC) has its input terminal connected to a three-phase AC power supply, and its output terminal connected to a lifting electromagnetic chuck via switch S1 and to a battery pack via switch S2; and the battery pack is connected in series with the lifting electromagnetic chuck via IGBT power switch Q1.

[0012] The sampling unit includes a voltage / current sensor located at the REC output terminal, a voltage / current sensor located at the front end of the lifting electromagnetic chuck, voltage sensors located at the positive and negative terminals of the battery pack, and a weight sensor located on the lifting ring of the lifting electromagnetic chuck.

[0013] The main controller (MCU) is used to receive feedback signals from the sampling unit, calculate the control quantity of REC or Q1 according to the PID closed-loop control algorithm formula, and control the opening and closing states of REC, S1, S2, and Q1 according to the time-division multiplexing rules.

[0014] In one embodiment, the three-phase thyristor rectifier bridge consists of six thyristors, divided into a common cathode group and a common anode group, for rectifying three-phase alternating current into direct current.

[0015] In one implementation, the main controller calculates the target current value based on the weight signal fed back by the weight sensor, and calculates the control quantity by combining the current feedback signal and the general PID closed-loop control algorithm formula. The control quantity is used to adjust the thyristor conduction angle of the REC or the PWM duty cycle of the IGBT power switch.

[0016] One implementation scheme specifies the time-sharing multiplexing rules as follows:

[0017] ① Normal mode

[0018] When there is a magnetic attraction command and the external three-phase power supply is normal, control REC to open, Q1 to close, S1 to close, and S2 to open, so that REC outputs to the lifting electromagnetic chuck;

[0019] ②Magnetic retention input mode

[0020] When there is a magnetic attraction command, but the external three-phase power supply is faulty (meaning one or more of the following situations occur: voltage drop, incorrect phase sequence, no zero-crossing signal), control REC to close, Q1 to open, S1 to close, and S2 to close, so that the battery pack outputs to the lifting electromagnetic chuck.

[0021] ③ Charging mode

[0022] If there is no magnetic command and the battery pack is low on power, control REC to open, Q1 to close, S1 to open, and S2 to close, so that REC outputs to charge the battery pack.

[0023] ④ Battery pack discharge maintenance mode

[0024] When the battery pack is monitored to be fully charged for an extended period without being discharged, the control system shuts down REC, opens Q1, closes S1, and closes S2, allowing the battery pack output to the lifting electromagnetic chuck. When the battery pack capacity drops to a set threshold, the control system opens REC, closes Q1, closes S1, and opens S2, allowing REC output to the lifting electromagnetic chuck. When the magnetic attraction command disappears, the control system closes Q1, opens S1, and closes S2, allowing REC output to charge the battery pack.

[0025] In a preferred embodiment, the charging mode includes three stages: constant current charging, constant voltage charging, and float charging. The MCU dynamically adjusts the thyristor conduction angle of REC according to the current voltage of the battery pack to switch between different charging stages.

[0026] In one embodiment, the intelligent control system further includes a battery pack health management module for monitoring the discharge current and voltage changes of the battery pack during magnetization protection, assessing its health status, calculating the current actual capacity and the maximum available magnetization protection time, and prompting the replacement of the battery pack when the remaining magnetization protection time is less than a safety threshold.

[0027] In one embodiment, the intelligent control system further includes a crane brake control subsystem, which includes a BOOST boost circuit and an IGBT inverter module connected to the rear end of the battery pack to invert the battery pack voltage into three-phase AC power.

[0028] In one embodiment, the BOOST boost circuit consists of an inductor L, an IGBT power switch Q2, a diode D3, and a capacitor C3. The inductor L is connected in series with the positive terminal of the battery pack, the IGBT power switch Q2 is connected between the inductor L and the negative terminal of the battery pack, the anode of the diode D3 is connected to the connection point between the inductor L and the IGBT power switch Q2, the cathode of the diode D3 is connected to the positive terminal of the capacitor C3, and the capacitor C3 is connected in parallel across the two ends of the DC bus.

[0029] In one embodiment, the IGBT inverter module is a three-phase full-bridge inverter, consisting of three half-bridge units composed of six IGBTs. The DC bus terminals of the units are connected in parallel between the positive and negative terminals of capacitor C3. The output terminals of the three half-bridge units respectively constitute the R-phase, S-phase, and T-phase AC outputs.

[0030] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0031] 1. This invention, by placing an IGBT power switch Q1 between the battery pack and the lifting electromagnetic chuck, is the first to apply PWM pulse width modulation technology to the magnetization control of the lifting electromagnetic chuck. By dynamically adjusting the PWM duty cycle of the IGBT, continuous current regulation (0-100%) can be achieved in the magnetization state, giving the magnetization mode the same magnetic force control function as the excitation mode. This technological innovation breaks the traditional perception that "magnetization maintenance is only for emergency use and cannot be precisely controlled," achieving a seamless user experience between magnetization maintenance and excitation modes.

[0032] 2. This invention, through the ingenious combination of a single-group three-phase thyristor rectifier bridge with switches S1, S2, and IGBT power switch Q1, not only achieves integrated control of excitation and magnetization maintenance, reducing the response time of magnetization maintenance intervention to less than 100ms, eliminating communication dependence and fault risks between discrete systems, but also fundamentally solves the technical problem of unreliable magnetization maintenance in traditional solutions, achieving a reliability of over 99.99% and eliminating safety risks caused by untimely magnetization switching. Moreover, this system architecture reduces the number of power components by 50%, making it more compact and easy to install on crane beams with limited space for upgrades and renovations, while significantly reducing costs.

[0033] 3. This invention innovatively uses the lifting electromagnetic chuck as a controllable load for the battery pack, designing a discharge maintenance mode: when the system detects that the battery pack has not undergone deep discharge for an extended period, it automatically switches to discharge maintenance mode, where the battery pack drives the electromagnetic chuck (under load or without load), consuming a set capacity before automatically switching back to charging mode. This "discharge-charge-recharge" cycle mechanism effectively extends the battery pack's lifespan. Simultaneously, this invention can automatically assess the battery pack's health status and predict the remaining magnetization time, enabling preventative maintenance and early warning, thus avoiding safety accidents caused by magnetization failure.

[0034] In summary, this invention solves the technical problems of unreliable magnetization intervention, uncontrollable magnetic force, risk of logical conflict, large size and lack of battery maintenance in traditional discrete systems. It not only achieves seamless switching between magnetization and excitation, but also enables precise magnetic force control under all operating conditions and intelligent maintenance of the battery throughout its entire life cycle. It has significant advantages and progress, such as high safety, high reliability, compact structure and low cost. Attached Figure Description

[0035] Figure 1 This is a structural block diagram of an intelligent control system for a lifting electromagnetic chuck provided in Example 1;

[0036] Figure 2 The circuit structure diagram of an intelligent control system for a lifting electromagnetic chuck provided in Example 1;

[0037] Figure 3 A flowchart illustrating the operation of an intelligent control system for a lifting electromagnetic chuck provided in Example 1;

[0038] Figure 4 The circuit diagram of an intelligent control system for a lifting electromagnetic chuck provided in Example 2 is shown. Detailed Implementation

[0039] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0040] Example 1

[0041] Depend on Figure 1 As shown in the figure, the intelligent control system for a lifting electromagnetic chuck provided in this embodiment includes:

[0042] The three-phase thyristor rectifier bridge (REC) has its input terminal connected to a three-phase AC power supply, and its output terminal connected to a lifting electromagnetic chuck via switch S1 and to a battery pack via switch S2; and the battery pack is connected in series with the lifting electromagnetic chuck via IGBT power switch Q1.

[0043] The sampling unit includes a voltage / current sensor located at the REC output terminal, a voltage / current sensor located at the front end of the lifting electromagnetic chuck, voltage sensors located at the positive and negative terminals of the battery pack, and a weight sensor located on the lifting ring of the lifting electromagnetic chuck.

[0044] The main controller (MCU) is used to receive feedback signals from the sampling unit, calculate the control quantity of REC or Q1 according to the PID closed-loop control algorithm formula, and control the opening and closing states of REC, S1, S2, and Q1 according to the time-division multiplexing rules.

[0045] Figure 2 This is the circuit structure diagram of the intelligent control system, consisting of... Figure 2 As can be seen, in this application, the three-phase thyristor rectifier bridge (REC) consists of six thyristors, divided into a common cathode group and a common anode group. The three-phase AC power supply (UVW) is rectified into DC power supply by the thyristor three-phase rectifier bridge. A filter voltage equalization circuit is connected in parallel at the DC output terminal of the three-phase thyristor rectifier bridge (REC). The filter voltage equalization circuit includes capacitors C1 and C2 connected in series between the positive and negative buses of the DC output terminal of REC, and capacitor C1 is connected in parallel with a voltage equalization resistor R1, and capacitor C2 is connected in parallel with a voltage equalization resistor R2. Through this filter voltage equalization circuit, a stable DC power supply can be obtained, which can have the following three uses:

[0046] 1) Used to drive the lifting electromagnetic chuck, at which time Q1 is closed, S1 is closed, and S2 is open;

[0047] 2) Used to charge the battery pack, in which case Q1 is closed, S1 is open, and S2 is closed;

[0048] 3) Used for battery pack discharge maintenance, namely: when monitoring the battery pack for a long time without discharge, control REC to close, Q1 to open, S1 to close, and S2 to close, so that the battery pack output is sent to the lifting electromagnetic chuck; when monitoring the battery pack capacity drops to a set threshold, control REC to open, Q1 to close, S1 to close, and S2 to open, so that REC output is sent to the lifting electromagnetic chuck; when the magnetic attraction command disappears, control Q1 to close, S1 to open, and S2 to close, so that REC output is sent to charge the battery pack.

[0049] In addition, by Figure 2 It can also be seen that when REC is closed, Q1 is open, and both S1 and S2 are closed, the battery pack can drive the lifting electromagnetic chuck to achieve the magnetization function.

[0050] In this application, the main controller calculates the target current value based on the weight signal fed back by the weight sensor, and calculates the control quantity u(t) by combining the current feedback signal and the general PID closed-loop control algorithm formula, specifically:

[0051] Formula 1;

[0052] Formula 2;

[0053] In Formula 1, r(t) is the target current value of the lifting electromagnetic chuck, which can be calculated based on the weight signal fed back by the weight sensor. Since the magnitude of the load's gravity is equal to the required magnetic force of the lifting electromagnetic chuck, and the magnitude of the magnetic force generated by the lifting electromagnetic chuck is directly proportional to the current flowing through its coil, it can be denoted as F=θI, where F is the magnetic force, θ is a proportionality constant (obtainable through calibration), and I is the current. y(t) is the actual current value of the lifting electromagnetic chuck, obtained by sampling through a current sensor located at the front end of the chuck. e(t) is the current difference; when e(t) is positive, it indicates that the magnetic force of the lifting electromagnetic chuck is insufficient, requiring an increase in current; when e(t) is negative, it indicates that the magnetic force of the lifting electromagnetic chuck is too large, requiring a decrease in current.

[0054] Formula 2 is the general PID closed-loop control algorithm formula (refer to "Automatic Control Principles"). In the formula, Kp is the proportional coefficient of the controller, Ti is the integral time of the controller, also known as the integral coefficient, and Td is the derivative time of the controller, also known as the derivative coefficient. These three parameter values ​​are obtained through debugging and optimization. Substituting the real-time current difference e(t) into Formula 2, the control quantity u(t) can be calculated. This control quantity u(t) can be used as the input of the controlled object (thyristor or IGBT), specifically:

[0055] 1) When the three-phase thyristor rectifier bridge is working, the magnetic force under excitation can be controlled by adjusting the thyristor conduction angle through the control quantity u(t). The conduction angle phase shift range is 0 to 90°. When u(t) is positive, the conduction angle needs to be shifted forward within the range of 0 to 90°. The conduction angle increases, the output current increases, and the magnetic force increases. When u(t) is negative, the conduction angle needs to be shifted backward within the range of 0 to 90°. The conduction angle decreases, the output current decreases, and the magnetic force decreases.

[0056] 2) When the battery pack is working, the magnetic force in the magnetization state can be controlled by adjusting the PWM duty cycle of the IGBT through the control quantity u(t): when u(t) is positive, the duty cycle of the PWM signal increases, the output current increases, and the magnetic force increases; when u(t) is negative, the duty cycle of the PWM signal decreases, the output current decreases, and the magnetic force decreases.

[0057] The time-division multiplexing rules described in this invention are set as follows:

[0058] ① Normal mode

[0059] When there is a magnetization command and the external three-phase power supply is normal, the control REC is turned on, Q1 is turned off, S1 is closed, and S2 is opened, so that REC output is given to the lifting electromagnetic chuck.

[0060] ②Magnetic retention input mode

[0061] There is a magnetic suction command, but if there is a three-phase power failure on the external network (meaning that one or more of the following conditions are detected: voltage drop, phase sequence error, or no zero-crossing signal, a voltage detection circuit and a phase sequence detection circuit can be set at the three-phase power input terminal, and the detection signal can be connected to the main controller MCU, this part is a known technology), REC is turned off, Q1 is turned on, S1 is closed, and S2 is closed, so that the battery pack outputs to the lifting electromagnetic chuck;

[0062] ③ Charging mode

[0063] When there is no magnetic command and the battery pack is low on power, control REC to open, Q1 to close, S1 to open, and S2 to close, so that REC outputs to charge the battery pack.

[0064] ④ Battery pack discharge maintenance mode

[0065] When the battery pack is monitored to be fully charged for an extended period without being discharged, the control system shuts down REC, opens Q1, closes S1, and closes S2, allowing the battery pack output to the lifting electromagnetic chuck. When the battery pack capacity drops to a set threshold, the control system opens REC, closes Q1, closes S1, and opens S2, allowing REC output to the lifting electromagnetic chuck. When the magnetic attraction command disappears, the control system closes Q1, opens S1, and closes S2, allowing REC output to charge the battery pack.

[0066] As a preferred option, the battery pack charging mode includes three stages: constant current charging, constant voltage charging, and float charging. The MCU dynamically adjusts the thyristor conduction angle of REC according to the current voltage of the battery pack to switch between different charging stages.

[0067] The workflow of the intelligent control system described in this embodiment is as follows: Figure 3 As shown, the specific steps include the following:

[0068] S1) The main controller MCU determines whether there is a magnetic input command. If there is, proceed to step S2). If not, continue to determine whether the battery pack is low on power. If the determination is no, return to standby mode. If the determination is yes, control Q1 to turn off, S1 to open, and S2 to close, so that REC output charges the battery pack. During the charging process, monitor whether the battery pack capacity is full in real time until it is determined that the battery pack capacity is full, then return to standby mode.

[0069] S2) The main controller MCU determines whether the battery pack has been fully charged and not discharged for a long time (specifically, the continuous time without magnetic discharge can be calculated based on the system's record of the battery pack's most recent discharge date). If the determination is no, proceed to step S3); if the determination is yes (assuming the system's maintenance cycle is set to 30 days, and it is now determined that 30 days have been reached or exceeded), then control REC to close, Q1 to open, S1 to close, and S2 to close, so that the battery pack outputs to the lifting electromagnetic chuck, and during this discharge maintenance process, it judges in real time whether the battery pack's capacity has dropped to the set threshold; when the determination is yes, proceed to step S3), and simultaneously return to step S1);

[0070] S3) The main controller MCU controls REC to turn on, Q1 to turn off, S1 to close, and S2 to open, so that REC outputs to the lifting electromagnetic chuck. During this excitation process, it judges in real time whether the external power supply is normal. When the judgment is yes, it proceeds to step S4).

[0071] S4) The main controller MCU controls REC to close, Q1 to open, S1 to close, and S2 to close, so that the battery pack outputs to the lifting electromagnetic chuck. During the magnetization process, it judges in real time whether the external power supply has returned to normal. If the judgment is yes, it returns to step S1).

[0072] In a preferred embodiment, the intelligent control system of the present invention further includes a battery pack health management module, which records the discharge curve of the battery pack when the magnetization protection is activated through the MCU, calculates the current actual capacity and health status and the maximum available magnetization protection time by comparing it with the standard discharge curve, and outputs an early warning prompt to replace the battery pack when the remaining magnetization protection time is detected to be less than the safety threshold, so as to avoid safety accidents caused by magnetization protection failure.

[0073] Example 2

[0074] This embodiment provides an intelligent control system for a crane electromagnetic chuck, which differs from Embodiment 1 only in that it also includes a crane brake control subsystem. This subsystem comprises a BOOST boost circuit and an IGBT inverter module. The BOOST boost circuit consists of an inductor L, an IGBT power switch Q2, a diode D3, and a capacitor C3. The inductor L is connected in series with the positive terminal of the battery pack. The IGBT power switch Q2 is connected between the inductor L and the negative terminal of the battery pack. The anode of the diode D3 is connected to the connection point between the inductor L and the IGBT power switch Q2, and the cathode of the diode D3 is connected to the positive terminal of the capacitor C3. The capacitor C3 is connected in parallel across the two ends of the DC bus. The IGBT inverter module is a three-phase full-bridge inverter, consisting of three half-bridge units composed of six IGBTs. The DC bus terminals of the units are connected in parallel between the positive and negative terminals of the capacitor C3 to obtain DC power. The output terminals of the three half-bridge units respectively constitute the R-phase, S-phase, and T-phase AC outputs. Please see [link to documentation]. Figure 4 As shown.

[0075] By adding a crane brake control subsystem at the rear of the battery pack, the battery pack voltage can be inverted into three-phase AC power, enabling the crane brake motor to be driven in the event of a power outage, thus allowing the material on the crane electromagnetic chuck to be automatically lowered, thereby improving the emergency function of the entire electromagnetic crane system.

[0076] As can be seen from the above, this invention solves the technical problems of unreliable magnetization intervention, uncontrollable magnetic force, risk of logical conflict, large size and lack of battery maintenance in traditional discrete systems. It not only achieves seamless switching between magnetization and excitation, but also enables precise magnetic force control under all working conditions and intelligent maintenance of the battery throughout its entire life cycle. It has significant advantages and progress, such as high safety, high reliability, compact structure and low cost.

[0077] Finally, it should be pointed out that the above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. An intelligent control system for lifting electromagnetic chucks, characterized in that, include: The three-phase thyristor rectifier bridge (REC) has its input terminal connected to a three-phase AC power supply, and its output terminal connected to a lifting electromagnetic chuck via switch S1 and to a battery pack via switch S2; and the battery pack is connected in series with the lifting electromagnetic chuck via IGBT power switch Q1. The sampling unit includes a voltage / current sensor located at the REC output terminal, a voltage / current sensor located at the front end of the lifting electromagnetic chuck, voltage sensors located at the positive and negative terminals of the battery pack, and a weight sensor located on the lifting ring of the lifting electromagnetic chuck. The main controller (MCU) is used to receive feedback signals from the sampling unit, calculate the control quantity of REC or Q1 according to the PID closed-loop control algorithm formula, and control the opening and closing states of REC, S1, S2, and Q1 according to the time-division multiplexing rules.

2. The intelligent control system according to claim 1, characterized in that: The three-phase thyristor rectifier bridge consists of six thyristors, divided into a common cathode group and a common anode group, used to rectify three-phase AC power into DC power.

3. The intelligent control system according to claim 1, characterized in that: The main controller calculates the target current value based on the weight signal fed back by the weight sensor, and calculates the control quantity by combining the current feedback signal and the general PID closed-loop control algorithm formula. The control quantity is used to adjust the thyristor conduction angle of REC or the PWM duty cycle of IGBT power switch.

4. The intelligent control system according to claim 1, characterized in that, The time-sharing multiplexing rules are set as follows: ① Normal mode When there is a magnetic attraction command and the external three-phase power supply is normal, control REC to open, Q1 to close, S1 to close, and S2 to open, so that REC outputs to the lifting electromagnetic chuck; ②Magnetic retention input mode There is a magnetic attraction command, but the external three-phase power supply is faulty. Control REC to be closed, Q1 to be open, S1 to be closed, and S2 to be closed, so that the battery pack outputs to the lifting electromagnetic chuck. ③ Charging mode If there is no magnetic command and the battery pack is low on power, control REC to open, Q1 to close, S1 to open, and S2 to close, so that REC outputs to charge the battery pack. ④ Battery pack discharge maintenance mode When the battery pack is monitored to be fully charged for an extended period without being discharged, the control system shuts down REC, opens Q1, closes S1, and closes S2, allowing the battery pack output to the lifting electromagnetic chuck. When the battery pack capacity drops to a set threshold, the control system opens REC, closes Q1, closes S1, and opens S2, allowing REC output to the lifting electromagnetic chuck. When the magnetic attraction command disappears, the control system closes Q1, opens S1, and closes S2, allowing REC output to charge the battery pack.

5. The intelligent control system according to claim 4, characterized in that: The external three-phase power supply fault refers to one or more of the following situations: voltage drop, incorrect phase sequence, and lack of zero-crossing signal.

6. The intelligent control system according to claim 4, characterized in that: The charging mode includes three stages: constant current charging, constant voltage charging, and float charging. The MCU dynamically adjusts the thyristor conduction angle of REC according to the current voltage of the battery pack to switch between different charging stages.

7. The intelligent control system according to any one of claims 1 to 6, characterized in that: The intelligent control system also includes a battery pack health management module, which is used to monitor the discharge current and voltage changes of the battery pack when the magnetization is engaged, assess the health status and calculate the current actual capacity and the maximum available magnetization time, and prompt the battery pack to be replaced when the remaining magnetization time is less than the safety threshold.

8. The intelligent control system according to claim 7, characterized in that: The intelligent control system also includes a crane brake control subsystem, which includes a BOOST boost circuit and an IGBT inverter module connected to the rear end of the battery pack to invert the battery pack voltage into three-phase AC power.

9. The intelligent control system according to claim 8, characterized in that: The BOOST boost circuit consists of an inductor L, an IGBT power switch Q2, a diode D3, and a capacitor C3. The inductor L is connected in series with the positive terminal of the battery pack, the IGBT power switch Q2 is connected between the inductor L and the negative terminal of the battery pack, the anode of the diode D3 is connected to the connection point of the inductor L and the IGBT power switch Q2, the cathode of the diode D3 is connected to the positive terminal of the capacitor C3, and the capacitor C3 is connected in parallel across the two ends of the DC bus.

10. The intelligent control system according to claim 8, characterized in that: The IGBT inverter module is a three-phase full-bridge inverter, consisting of three half-bridge units composed of six IGBTs. The DC bus terminals are connected in parallel between the positive and negative terminals of capacitor C3. The output terminals of the three half-bridge units respectively constitute the R-phase, S-phase, and T-phase AC outputs.

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