Wide slab electromagnetic stirring with sectioned roller power supply system synchronization control method and system

Abstract

The application discloses a kind of wide slab electromagnetic stirring with section roller power supply system synchronous control method, system, in the feedback control link of each power unit output current, join phase and frequency compensation instruction, control each power unit output current and specified reference current synchronization, satisfy electromagnetic stirring power multi-roller synchronous electromagnetic stirring requirement.Through real-time detection of the output current of each power supply, and by extracting the amplitude and phase of the output current in real time through the phase-locked loop, introduce the center phase and its offset on the basis of multi-channel phase coupling of each unit, and compensate to the current angular frequency, and real-time join current instruction, improve the synchronization control precision of power supply system, realize the synchronization function of the output current of multiple two-phase orthogonal power supplies.Therefore, for the multiple electromagnetic stirring rollers that need to output the same magnetic potential, the control method of the application can solve the problem of mutual cancellation of multi-roller synchronous electromagnetic stirring force.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic metallurgical equipment drive control technology, and in particular to a synchronous control method and system for a segmented roller power supply system for electromagnetic stirring of thick slabs. Background Technology

[0002] In the metallurgical industry, continuous casting is a landmark process in the modernization of steel production, achieving high efficiency, energy saving, automation, and high quality in steel production. It is an indispensable core process in the production of modern steel enterprises. Applying electromagnetic stirring technology to continuous casting production can significantly improve the quality of cast billets, while also making the continuous casting process more stable, reducing the leakage rate, and increasing the billet drawing speed. This technology mainly utilizes the alternating magnetic field generated by the electromagnetic stirrer to act on the unsolidified liquid phase in the continuously cast billet to enhance the movement of the liquid phase, thereby strengthening the homogenization and temperature homogenization process of the liquid phase. This can inhibit the growth of columnar crystals, promote the expansion of equiaxed crystals, reduce the porosity of central shrinkage cavities, and improve the microstructure of the cast billet, thus significantly improving the internal and external defects of the continuously cast billet.

[0003] Among them, the electromagnetic stirring power supply, as a key component of the electromagnetic stirring system, directly affects the quality and yield of continuously cast steel due to its current waveform quality and response speed. The segmented roller electromagnetic stirrer consists of two pairs of electromagnetic stirring rollers arranged above and below the slab. The output current of the two-phase quadrature power supply applied to the stirring rollers varies and requires frequent alternation between forward and reverse directions. This necessitates high dynamic tracking performance of the output current. Furthermore, when the molten steel undergoes frequent and rapid forward and reverse electromagnetic stirring switching, the mechanical kinetic energy of the molten steel is converted into electromagnetic energy by the stirrer and needs to be rapidly released in the stirring power supply, leading to high difficulty in power supply control. Moreover, when multiple electromagnetic stirring power supplies are used simultaneously, their output currents become unbalanced and asynchronous, and their dynamic tracking performance is poor. This causes the electromagnetic stirring forces generated by the multiple rollers to cancel each other out, resulting in uncontrollable magnetic fields. This severely impacts the stable operation of the electromagnetic stirring system, leading to substandard quality of the produced steel slabs and significantly affecting the product qualification rate. Therefore, researching the segmented roller power supply system for electromagnetic stirring of thick slabs and its synchronous control method is of great significance. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a synchronous control method and system for a segmented roller power supply system for electromagnetic stirring of thick slabs, which addresses the shortcomings of the existing technology. This method solves the problems of asynchronous output current and poor dynamic current tracking performance when multiple electromagnetic stirring power supplies are used together, resulting in mutual cancellation of electromagnetic stirring forces and uncontrollable magnetic fields.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a synchronous control method for a segmented roller power supply system for electromagnetic stirring of thick slabs, comprising the following steps:

[0006] S1. At the beginning of each sampling period, the inverter output current in the x-th power supply is... , , Sampling is performed, where x = 1, 2, 3;

[0007] S2, Utilizing the inverter output current of the xth power source. The phase θ of the working current of phase a is calculated. x ;

[0008] S3, Based on the phase θ of the a-phase working current x Introducing the center phase offset between the x-th power source and all power sources, the multi-channel phase coupling offset compensation value based on the center phase is calculated. ;

[0009] S4, combined with the given current command With the rated angular frequency The multi-channel phase coupling offset compensation value Phase difference proportional gain coefficient K w After multiplication, the angular frequency of each power supply is compensated, and three power supplies are constructed respectively. Three-phase current command value , and ;

[0010] S5, Set the three-phase current command value , and Corresponding to the detected current i ax i bx and i cx The difference is calculated, and the error is sent to the current regulator G of the three two-phase quadrature inverter power supply systems. PR1 (s), G PR2 (s) and G PR3 (s), thereby obtaining the duty cycle signal m of the driving signal respectively. ax m bx and m cx ;

[0011] S6. The duty cycle signal m ax m bx and m cx The signals are sent to the drive circuits of the three two-phase quadrature inverter power supply systems to generate drive signals, which drive the three-phase inverter bridges of the three two-phase quadrature inverter power supply systems.

[0012] In step S2, the multi-channel phase coupling offset compensation value The calculation formula is:

[0013] ;

[0014] Among them, K m K n For phase compensation gain, K p K i These are the proportional and integral coefficients of the PI controller, respectively. The central phase at time t, and θ m (t), θ n (t) represents the phase of the working current of phase a at time t for the xth power source and the remaining two power sources, respectively.

[0015] The center phase Set to the phase average of all power supplies.

[0016] In step S3, three power supplies Three-phase current command value , and The calculation formula is as follows:

[0017] ;

[0018] ;

[0019] .

[0020] As an inventive concept, the present invention also provides a synchronous control system for a segmented roller power supply system for electromagnetic stirring of thick slabs, including a memory, a processor, and a computer program stored in the memory; the processor executes the computer program to implement the steps of the above method.

[0021] As an inventive concept, the present invention also provides a computer-readable storage medium having a computer program / instructions stored thereon; when the computer program / instructions are executed by a processor, they implement the steps of the above-described method.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention realizes the output synchronization of the segmented roller power supply system for electromagnetic stirring of thick slabs, and solves the problem of mutual cancellation of electromagnetic stirring forces of multiple rollers. Attached Figure Description

[0023] Figure 1 This is a structural block diagram of a segmented roller power supply system for electromagnetic stirring of thick slabs according to an embodiment of the present invention;

[0024] Figure 2 This is a block diagram of a multi-channel phase coupling offset compensation control system based on the center phase for a segmented roller power supply system for electromagnetic stirring of wide and thick slabs according to an embodiment of the present invention.

[0025] Figure 3 This is a simulation waveform of the output current of a segmented roller power supply system for electromagnetic stirring of thick slabs according to an embodiment of the present invention, operating in three working states: forward rotation, stop rotation, and reverse rotation, without the proposed control.

[0026] Figure 4 This is a simulation waveform diagram of the output current of a segmented roller power supply system for electromagnetic stirring of wide and thick slabs according to an embodiment of the present invention, operating in three working states: forward rotation, stop rotation, and reverse rotation, with the proposed control added.

[0027] Figure 5 In an embodiment of the present invention, the power supply system for the segmented rollers used in electromagnetic stirring of thick slabs operates in three states: forward rotation, stop, and reverse rotation. The phase difference θ between the output phase of the i-th power supply and the center phase is... 1p Simulation waveform diagrams, i=1,2,3; (a), (b), and (c) represent the differences between the output phase and center phase of the 1st, 2nd, and 3rd power supplies, respectively, when the system achieves forward and reverse switching operation without the control proposed in this embodiment and with the proposed control. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Example 1

[0030] Embodiment 1 of the present invention provides a synchronous control method for a segmented roller power supply system for electromagnetic stirring of thick slabs, applicable to a two-phase quadrature inverter power supply system for multi-roller synchronous electromagnetic stirring: the three two-phase quadrature power supplies each include a DC power supply, a DC side energy storage capacitor, a two-phase quadrature inverter circuit and three output filter inductors, and the load is an electromagnetic stirrer; all three two-phase quadrature power supplies are connected to a central controller.

[0031] like Figure 1 As shown, after sampling the output current of the three two-phase quadrature power supplies, the phase is extracted through a phase-locked loop. The central controller generates a three-phase current command value based on the received current command and phase information and sends it to each power supply unit. Then, the current error is sent to the current regulator G of the three sets of equipment respectively. PR1 (s), G PR2 (s) and G PR3(s) generates a drive signal through SVPWM modulation, which is used to drive the three-phase inverter bridge of the three two-phase quadrature inverter power supply system.

[0032] The control method of Embodiment 1 of the present invention includes the following steps:

[0033] Step 1: At the beginning of each sampling period, measure the inverter output current in the x-th power supply. , i cx Sampling is performed, where x = 1, 2, 3;

[0034] Step 2: Convert the inverter output current of the xth power source. The data is transmitted in real time to the phase-locked loop module to calculate the phase θ of the phase a operating current. x ;

[0035] Step 3: Based on the phase θ output by the phase-locked loop in Step 2 x Based on the multi-channel phase coupling offset between the x-th power supply and the remaining power supplies, a further phase offset between the x-th power supply and the center phase of all power supplies is introduced to design a multi-channel phase coupling offset compensation value based on the center phase. ;

[0036] Step 4: Combine with the given current command With the rated angular frequency Based on the phase compensation value obtained in step 3, the angular frequency of each power supply is compensated, and a central controller is designed to construct three power supplies. Three-phase current command value , and ;

[0037] Step 5: Set the three-phase current command value of the inverter from Step 4. , and With the detected current i ax i bx and i cx The difference is calculated, and then the error is sent to the current regulator G of the three sets of equipment respectively. PR1 (s), G PR2 (s) and G PR3 (s), thereby obtaining the duty cycle m of the driving signal respectively. ax m bx and m cx ; , where K p It is the proportional gain, K r It is the resonant gain, w0 is the resonant frequency, w c It is the cutoff bandwidth;

[0038] Step 6: Convert the duty cycle signal m obtained in Step 5 into a single signal. ax m bx and m cx The signals are sent to the drive circuits of the three devices to generate drive signals, which are used to drive the three-phase inverter bridge of the three two-phase quadrature inverter power supply systems.

[0039] Two-phase quadrature inverter phase and The phase output current is a low-frequency sinusoidal current with equal amplitude and frequency but a 90° phase difference. Phase c is the common current phase of the two-phase quadrature inverter, and is respectively connected to... Harmony The phases form a current loop, and the current flowing through phase c is phase and The sum of the two phase currents is the opposite number.

[0040] like Figure 2 As shown, the multi-channel phase coupling offset compensation based on the center phase in the synchronous control method of the segmented roller power supply system for electromagnetic stirring of wide and thick slabs in Embodiment 1 of the present invention mainly includes the following steps:

[0041] 1) Phase coupling offset between the i-th power supply and the j-th power supply (i=1,2,3,j≠i):

[0042]

[0043] Where, q i (t) and q j (t) represents the actual phase of the i-th and j-th power supplies.

[0044] 2) Phase offset of the i-th power supply from the center phase:

[0045]

[0046] 3) The multi-channel phase coupling offset compensation formula based on the center phase is:

[0047]

[0048] This invention achieves adaptive adjustment by introducing the center phase as a global reference and combining it with angular frequency compensation. Specifically, when the multi-channel phase coupling offset compensation value... When the phases are out of sync, the gain K is compensated by the phase difference. w Convert it to an angular frequency compensation value, and compensate for it up to the xth power supply, until... The angular frequency compensation value is also 0. Simultaneously, by tracking phase errors through local pairwise coupling and global central phase, it possesses strong robustness and anti-interference capabilities, ensuring precise phase synchronization of multiple channels in the segmented roller power supply system for electromagnetic stirring of wide and thick slabs.

[0049] like Figure 3 As shown, simulating a scenario where the outputs of three power supplies are out of sync and without the control method proposed in this embodiment of the invention, from 0s to 3s, the electromagnetic stirrer is in forward rotation driven by the two-phase quadrature inverter power supply; from 3s to 4s, it stops rotating, and the output current of the two-phase quadrature inverter power supply is 0; from 4s to 10s, the electromagnetic stirrer reverses direction driven by the two-phase quadrature inverter power supply. It is evident that without the control method proposed in this embodiment of the invention, the system cannot autonomously achieve phase synchronization of the output current.

[0050] like Figure 4 As shown, in Figure 3 Based on the operating conditions, the control method proposed in this embodiment of the invention is added. As can be seen from the magnified diagram of the output current in forward and reverse rotation, after adding the multi-channel phase coupling offset compensation control based on the center phase proposed in this embodiment of the invention, the output current waveforms of the three power supplies overlap and the output current is synchronized. Moreover, after switching from forward rotation to stop and then switching to reverse rotation, the system still stably maintains current synchronization.

[0051] like Figure 5 As shown, (a), (b), and (c) represent the differences q between the output phase and the center phase of the first, second, and third power supplies, respectively, when the system operates with forward and reverse switching without the control proposed in this embodiment and with the proposed control. ip It can be seen that after the control is applied, the output phases of the three power supplies accurately track the center phase, and the output current phases are synchronized.

[0052] In summary, the segmented roller power supply system and its synchronous control method for electromagnetic stirring of thick slabs adopted in the embodiments of the present invention effectively realize the output synchronization of the segmented roller power supply system for electromagnetic stirring of thick slabs, and solve the problem of mutual cancellation of electromagnetic stirring forces of multiple rollers.

[0053] Example 2

[0054] Embodiment 2 of the present invention provides a terminal device corresponding to Embodiment 1 above. The terminal device can be a processing device for a client, such as a mobile phone, a laptop, a tablet computer, a desktop computer, etc., to execute the method of the above embodiments.

[0055] The terminal device in this embodiment includes a memory, a processor, and a computer program stored in the memory; the processor executes the computer program in the memory to implement the steps of the method in Embodiment 1 described above.

[0056] In some implementations, the memory may be high-speed random access memory (RAM), and may also include non-volatile memory, such as at least one disk storage device.

[0057] In other implementations, the processor can be any type of general-purpose processor, such as a central processing unit (CPU) or a digital signal processor (DSP), and there is no limitation here.

[0058] Example 3

[0059] Embodiment 3 of the present invention provides a computer-readable storage medium corresponding to Embodiment 1 above, on which a computer program / instructions are stored. When the computer program / instructions are executed by a processor, they implement the steps of the method of Embodiment 1 above.

[0060] A computer-readable storage medium can be a tangible device that holds and stores instructions for use by an instruction execution device. A computer-readable storage medium can be, for example, but not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any combination thereof.

[0061] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. The solutions in the embodiments of this application can be implemented in various computer languages, such as the object-oriented programming language Java and the interpreted scripting language JavaScript.

[0062] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0063] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0064] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0065] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A synchronous control method for a segmented roller power supply system for electromagnetic stirring of thick slabs, characterized in that, Includes the following steps: S1. At the beginning of each sampling period, the inverter output current in the x-th power supply is... , , Sampling is performed, where x = 1, 2, 3; S2, Utilizing the inverter output current of the xth power source. The phase θ of the working current of phase a is calculated. x ; S3, Based on the phase θ of the a-phase working current x Introducing the center phase offset between the x-th power source and all power sources, the multi-channel phase coupling offset compensation value based on the center phase is calculated. ; S4, combined with the given current command With the rated angular frequency The multi-channel phase coupling offset compensation value Phase difference proportional gain coefficient K w After multiplication, the angular frequency of each power supply is compensated, and three power supplies are constructed respectively. Three-phase current command value , and ; S5, Set the three-phase current command value , and Corresponding to the detected current i ax i bx and i cx The difference is calculated, and the error is sent to the current regulator G of the three two-phase quadrature inverter power supply systems. PR1 (s), G PR2 (s) and G PR3 (s), thereby obtaining the duty cycle signal m of the driving signal respectively. ax m bx and m cx ; S6. The duty cycle signal m ax m bx and m cx The signals are sent to the drive circuits of the three two-phase quadrature inverter power supply systems to generate drive signals and drive the three-phase inverter bridges of the three two-phase quadrature inverter power supply systems. Among them, multi-channel phase coupling offset compensation value The calculation formula is: ； Among them, K m K n For phase compensation gain, K p K i These are the proportional and integral coefficients of the PI controller, respectively. The central phase at time t, and θ m (t), θ n (t) represents the phase of phase a of the operating current at time t for the x-th power supply and the remaining two power supplies, respectively; the center phase Set to the phase average of all power supplies.

2. The synchronous control method for the segmented roller power supply system for electromagnetic stirring of thick slabs according to claim 1, characterized in that, In step S3, three power supplies Three-phase current command value , and The calculation formula is as follows: ； ； 。 3. A synchronous control system for a segmented roller power supply system for electromagnetic stirring of thick slabs, comprising a memory, a processor, and a computer program stored in the memory; characterized in that, The processor executes the computer program to implement the steps of the method described in claim 1 or 2.

4. A computer-readable storage medium having a computer program / instructions stored thereon; characterized in that, When the computer program / instructions are executed by the processor, they implement the steps of the method described in claim 1 or 2.

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