Coordinated control method and system of dc de-icing device with parallel expansion on dc side of lcc

Abstract

A collaborative control method and system for DC de-icing devices in LCC DC-side parallel expansion is proposed. This method establishes constraints on the control parameters of the DC de-icing device to ensure system stability before de-icing. A compensation coefficient is introduced. Current deviation compensation is superimposed on the host voltage command to obtain a new host voltage command. Using the compensation coefficient, and based on the constraints on the control parameters of the DC de-icing device to ensure system stability before de-icing, constraints on the control parameters of the DC de-icing device to ensure system stability during de-icing are established. These constraints include a system stability criterion under line resistance temperature drift during de-icing. The compensation coefficient and the control parameters of the DC de-icing device are tuned according to the adjustability of the control parameters and the system stability criterion under line resistance temperature drift. Based on the tuned control parameters and compensation coefficient, collaborative control between the host and slave devices is executed, solving the current sharing failure problem caused by difficulty in controlling parameter tuning and inconsistent transformer ratios in LCC DC-side parallel expansion scenarios.

Description

Technical Field

[0001] This invention belongs to the field of DC de-icing and power electronics technology in power systems, specifically relating to a collaborative control method and system for a DC de-icing device with parallel expansion of the DC side of an LCC. Background Technology

[0002] With the increasing voltage levels of the power grid backbone, the demand for DC de-icing on 500kV and above transmission lines is becoming increasingly urgent. These lines require extremely high de-icing currents, posing a significant challenge to the capacity of de-icing devices. DC de-icing devices based on grid-commutated converters (LCCs) are technologically mature, relatively low-cost, and easily scaled up, making them the current mainstream solution. To meet the high-current de-icing requirements, operating multiple LCC converters in parallel on the DC side to achieve capacity expansion has become an inevitable technical choice.

[0003] However, parallel operation of LCC DC-side converters presents a series of inherent technical challenges at the control level: 1) Control parameter tuning and system stability issues: When the parallel converters adopt a master-slave control strategy (master voltage constant, slave current constant), the selection of control parameters directly affects system stability. Improper parameter tuning may lead to discontinuous or even zero current in the slave, rendering capacity expansion meaningless. Especially during de-icing, the line resistance drifts significantly with increasing temperature, causing the control parameters tuned at room temperature to become unstable as de-icing progresses. Existing technologies lack systematic parameter tuning methods, making it difficult to ensure stable operation throughout the entire de-icing process. 2) Current sharing issues caused by inconsistent transformer ratios: In practical engineering, it is difficult to achieve completely consistent transformer ratios in parallel converters. When the transformer ratio connected to the master is higher than that of the slave, if a traditional master-slave control strategy is adopted, the voltage command must be set sufficiently low; otherwise, the slave will be unable to participate in current regulation due to insufficient output voltage, and its current will decay to zero, rendering capacity expansion meaningless. This brings cumbersome procedures and operational risks to equipment selection and parameter tuning in field applications. Existing technologies lack a systematic control scheme that can comprehensively consider parameter stability and transformer turns ratio differences. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a collaborative control method and system for a DC de-icing device with parallel expansion of the LCC DC side. Addressing the current sharing failure problem caused by difficulties in control parameter tuning and inconsistent transformer ratios in LCC DC side parallel expansion scenarios, this invention proposes a collaborative control architecture of "master voltage constant + slave current constant." The control parameter constraints for system stability before de-icing are derived using the Hurwitz criterion. By introducing compensation coefficients, not only is a current deviation compensation term introduced in the master voltage command, but the integral coefficients of the master voltage loop and the slave current loop are also coupled together. This simplifies the control parameter tuning object from two to one, and it is applicable to any transformer ratio and satisfies scenarios with different line resistance temperature drift, fundamentally eliminating the impact of line resistance temperature drift and transformer ratio differences on system stability.

[0005] The present invention adopts the following technical solution.

[0006] This invention proposes a collaborative control method for a DC ice-melting device with parallel expansion of the DC side of LCCs. In the DC ice-melting device, one LCC is the master unit and the other LCCs are slave units. The master unit adopts constant DC voltage control and the slave units adopt constant DC current control. The methods include: Before de-icing, constraints are established on the control parameters of the DC de-icing device to ensure system stability before de-icing, based on the resistance of the de-icing line, the AC side voltage of the main unit, and the AC side voltage of the slave unit. A compensation coefficient is introduced. During ice melting, the current difference between the slave DC side current and the host DC side current is multiplied by the compensation coefficient to obtain a current deviation compensation term, which is then superimposed on the host voltage command to obtain a new host voltage command. Using the compensation coefficient, based on the constraint conditions of the DC ice melting device control parameters that are stable before ice melting, constraint conditions of the DC ice melting device control parameters that are stable during ice melting are established. These constraint conditions include the system stability criterion under line resistance temperature drift during ice melting. Based on the adjustability of the control parameters and the system stability judgment results under line resistance temperature drift, the compensation coefficient and the control parameters of the DC ice melting device are adjusted. Based on the control parameters and compensation coefficients of the DC ice-melting device obtained by tuning, the master and slave units perform coordinated control.

[0007] Preferably, the compensation coefficient and the control parameters of the DC ice-melting device are tuned, including: If the control parameters can be adjusted online, the compensation coefficient is set to the resistance of the de-icing line during de-icing; if the control parameters cannot be adjusted online and the system is determined to be stable under temperature drift of the line resistance, the compensation coefficient is set only to the resistance of the de-icing line before de-icing; if the control parameters cannot be adjusted online and the system is determined to be unstable under temperature drift of the line resistance, the control parameters of the DC de-icing device are adjusted based on the resistance of the de-icing line before de-icing, and the compensation coefficient is set to the resistance of the de-icing line before de-icing.

[0008] The control parameters of the DC de-icing device include: the integral coefficient of the constant DC voltage control of the main unit and the integral coefficient of the constant DC current control of the slave unit.

[0009] Using the Hurwitz criterion, the constant DC voltage control constraints and constant DC current control constraints for system stability before ice melting are established as follows:

[0010] In the formula, , , , These are the effective values ​​of the AC side voltages of the master and slave devices, respectively. , These are the integral coefficients for constant DC voltage control and constant DC current control, respectively. This represents the resistance of the de-icing circuit before de-icing.

[0011] Slave DC side current DC side current of the host The current difference between them multiplied by the compensation coefficient Obtain the current deviation compensation term New host voltage command , This is the host voltage command.

[0012] Based on the compensation coefficient, the constraints for updating the control parameters of the DC ice-melting device for system stability during ice melting are as follows:

[0013] In the formula, This is the compensation coefficient.

[0014] The constraints include system stability criteria under temperature drift of line resistance during de-icing. ; This indicates that the system is stable under temperature drift of the line resistance. This indicates system instability due to temperature drift in line resistance.

[0015] Another aspect of the present invention proposes a collaborative control system for a DC ice-melting device with parallel capacity expansion on the DC side of an LCC, comprising: The constraint condition establishment module is used to establish constraint conditions for the control parameters of the DC ice melting device that are stable before ice melting, based on the resistance of the ice melting line, the AC side voltage of the host and the AC side voltage of the slave. A compensation coefficient is introduced. During ice melting, the current difference between the slave DC side current and the host DC side current is multiplied by the compensation coefficient to obtain a current deviation compensation term, which is then superimposed on the host voltage command to obtain a new host voltage command. Using the compensation coefficient, based on the constraint conditions of the DC ice melting device control parameters that are stable before ice melting, constraint conditions of the DC ice melting device control parameters that are stable during ice melting are established. These constraint conditions include the system stability criterion under line resistance temperature drift during ice melting. The tuning module is used to tune the compensation coefficient and the control parameters of the DC de-icing device based on the adjustability of the control parameters and the system stability judgment results under the temperature drift of the line resistance. The master and slave units perform coordinated control based on the control parameters and compensation coefficients of the DC ice-melting device obtained through tuning.

[0016] The present invention is also a terminal, including a processor and a storage medium; the storage medium is used to store instructions; the processor is used to perform operations according to the instructions to execute the steps of the method.

[0017] The present invention is also a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method.

[0018] The beneficial effects of this invention are that, addressing the current sharing problem caused by inconsistent transformer turns ratios, it proposes an improved control strategy for the main unit, employing a voltage loop plus a current deviation compensation loop. By superimposing a current deviation compensation term onto the voltage command, the system's stability criterion is reconstructed, allowing terms involving line resistance to cancel each other on both sides of the inequality, thereby effectively reducing the impact of line resistance temperature drift on system stability. More importantly, this strategy reduces the design object from two (voltage loop integral coefficient and current loop integral coefficient) to one (compensation coefficient), and it has good adaptability to any transformer turns ratio, fundamentally eliminating the dependence on transformer turns ratio matching.

[0019] Through the synergistic design of the above two levels, this invention effectively solves the two key technical bottlenecks of control parameter tuning and transformer ratio difference adaptability in LCC parallel expansion, and significantly improves the engineering applicability, operational reliability and control flexibility of DC ice melting system. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the topology of the DC ice-melting device with parallel expansion of the DC side of the LCC in an embodiment of the present invention; Figure 2This is a flowchart of the collaborative control method for the DC ice-melting device with parallel expansion of the DC side of the LCC proposed in this invention; Figure 3 This is a block diagram of the improved host voltage command control strategy proposed in this invention; Figure 4 These are the time-varying curves of the master and slave currents in scenario ① under the conventional control strategy in this embodiment of the invention. Figure 5 These are the time-varying curves of the master and slave currents in scenario ② under the conventional control strategy in this embodiment of the invention. Figure 6 This is the curve showing the change of master and slave currents with respect to time in scenario ③ of this embodiment of the invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this invention. The embodiments described in this application are merely some embodiments of this invention, and not all embodiments. Based on the spirit of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this invention.

[0022] The topology of the DC-side parallel expansion DC de-icing device of LCC is as follows: Figure 1 As shown, the ice-melting device includes a rectifier bridge 1 and a rectifier bridge 2. The AC side of rectifier bridge 1 and the AC side of rectifier bridge 2 are connected to an AC power source via a rectifier transformer. The DC side of rectifier bridge 1 and the DC side of rectifier bridge 2 are both short-circuited after passing through an equivalent line resistor to form an ice-melting circuit. Both rectifier bridge 1 and rectifier bridge 2 are LCCs.

[0023] Based on the wiring configuration of the secondary winding of the rectifier transformer, this invention uses two LCCs connected in parallel on the DC side as the master and slave respectively. In the embodiment, the LCC connected to the Δ-type secondary winding is used as the master, and the LCC connected to the Y-type secondary winding is used as the slave. The Y-type secondary winding is preferred to suppress zero-sequence circulating current. If the secondary winding adopts the Yg type connection, it needs to be compensated in the subsequent control.

[0024] This invention proposes a collaborative control method for a DC ice-melting device with parallel capacity expansion on the DC side of an LCC (Liquid Cylinder Carrier). The main unit uses constant DC voltage control, and the slave unit uses constant DC current control. Figure 2 As shown, the method includes: Step 1: Before de-icing, based on the resistance of the de-icing line, the AC side voltage of the main unit, and the AC side voltage of the slave unit, the Hurwitz criterion is used to establish the constraint conditions for the control parameters of the DC de-icing device that ensures the stability of the system before de-icing.

[0025] Specifically, the equivalent resistance of the de-icing circuit before de-icing is the same as the circuit resistance before de-icing at room temperature. .

[0026] Specifically, this invention analyzes the feasibility of using constant DC voltage control for the master and constant DC current control for the slave when the transformer ratios of the master and slave are the same. Through theoretical derivation, the constraints on the control parameters are calculated to ensure system stability. This includes the following aspects: First, without considering the asymmetry of the positive and negative currents of the converter, and writing the voltage equations around the master and slave, we can obtain the equation set (1), (2), and (3) as follows: (1) (2) (3) In the formula, , These are the effective values ​​of the AC side voltages of the master and slave devices, respectively. , These are the DC side currents for the master and slave devices, respectively. , These are the trigger angles for the master and slave devices, respectively. , These are the integral coefficients for constant DC voltage control and constant DC current control, respectively. , These are the master voltage command and the slave current command, respectively. For de-icing current, This is the voltage for melting ice. The resistance of the de-icing circuit before de-icing. Add a series inductor to the DC side.

[0027] By solving the system of equations (1), (2), and (3) and performing a Laplace transform, we obtain: (4) The expression for the DC side current of the slave device is obtained as follows:

[0028] Using the final value theorem, the steady-state value of the slave current can be calculated:

[0029]

[0030]

[0031] Therefore, it can be seen that if a control strategy of constant voltage for the master and constant current for the slave is adopted, the slave can track the given current command. However, considering that the condition for the final value theorem to hold is that the poles of the expression (i.e., the zeros of the denominator) are all in the left half-plane, or... There is one and only one first-order pole at this point, therefore additional adjustments are needed to the denominator. Stability analysis is performed. Since it is not necessary to solve for the roots of the characteristic equation here, the Hurwitz criterion is used for calculation.

[0032] Since the order of the equation is 4, a 4×4 Herwitz matrix is ​​constructed as follows:

[0033] In the formula, , .

[0034] Based on this 4×4 Herwitz matrix, the necessary and sufficient condition for the system to be stable is that all coefficients of the characteristic polynomial are greater than 0, that is:

[0035] All leading principal minors of the Herwitz matrix should be greater than 0, i.e.:

[0036] Simplification yields .

[0037] Therefore, to ensure the system is stable before de-icing, the constant DC voltage control constraints and constant DC current control constraints are as follows: (5) In the formula, , These are the effective values ​​of the AC side voltages of the master and slave units, respectively. Their magnitudes are related to many factors, including higher primary voltage levels, larger transformer turns ratios, smaller transformer leakage reactance, and smaller load currents, all of which will increase their values. However, considering that the transformer leakage reactance is extremely small and the primary sides of the transformers are connected to the same AC bus, therefore... , It is mainly related to the transformer turns ratio. Since we are assuming that the transformer turns ratio is consistent for now, therefore... = In summary, to ensure system stability, both the integral coefficients of constant voltage control and constant current control should be greater than 0, and the integral coefficient of constant current control should be greater than the product of the integral coefficient of constant voltage control and the load resistance.

[0038] The Hurwitz criterion is common knowledge in control theory and is usually used for stability analysis. In this invention, the Hurwitz criterion is applied to the parameter tuning of a parallel LCC de-icing device, and specific parameter constraint inequalities are derived. Step 2: Introduce a compensation coefficient. During ice melting, the current difference between the slave DC side current and the host DC side current is multiplied by the compensation coefficient to obtain a current deviation compensation term, which is then superimposed on the host voltage command to obtain a new host voltage command. Using the compensation coefficient, based on the constraint conditions of the DC ice melting device control parameters that are stable before ice melting, constraint conditions of the DC ice melting device control parameters that are stable during ice melting are established. These constraint conditions include the system stability criterion under line resistance temperature drift during ice melting.

[0039] Specifically, the DC side current of the machine DC side current of the host The current difference between them multiplied by the compensation coefficient Obtain the current deviation compensation term New host voltage command , This is the host voltage command.

[0040] The block diagram of the improved host voltage command control strategy proposed in this invention is as follows: Figure 3 As shown, the new host voltage command With ice melting voltage The difference is integrated Limiting, inverse cosine Solve the host trigger angle And the three-phase voltage on the AC side obtained via phase-locked loop , The frequency is angular, and the pulse generator is based on the firing angle. and Output pulse sequence.

[0041] As shown in step 1, to ensure stable system operation, the control parameters set by the master and slave devices must meet the following requirements. However, during the ice melting process, the line resistance will experience temperature drift, leading to an increase in line resistance. Since control parameters are typically set at room temperature, even with margins, they may become unstable as ice melting progresses. Therefore, this invention proposes an improved control strategy to eliminate the impact of line resistance temperature drift.

[0042] After adding the current deviation compensation term, the following system of equations can be written: (6) (7) (8) Based on the constraints of the control parameters of the DC ice-melting device for system stability before ice melting, the Hurwitz stability criterion is applied for analysis. The necessary and sufficient condition for system stability is derived as follows:

[0043] In the formula, , .

[0044] Further simplifying the equation, the constraint conditions for updating the control parameters of the DC ice-melting device for system stability during ice melting, based on the compensation coefficient, are shown in the following equation:

[0045] Compared to the previous criterion, the constraint conditions now include a compensation coefficient after the introduction of the current deviation compensation term. It also includes system stability criteria for line resistance temperature drift during de-icing. .

[0046] Step 3: Based on the adjustability of the control parameters and the system stability judgment results under line resistance temperature drift, adjust the compensation coefficient and the control parameters of the DC de-icing device.

[0047] If the control parameters can be adjusted online, the compensation coefficient is set to the resistance of the de-icing line during de-icing. If the control parameters cannot be adjusted online and the system is determined to be stable under the temperature drift of the line resistance, the compensation coefficient is set to the resistance of the de-icing line before de-icing. If the control parameters cannot be adjusted online and the system is determined to be unstable due to temperature drift of the line resistance, the control parameters of the DC de-icing device are adjusted based on the resistance of the de-icing line before de-icing, and the compensation coefficient is set to the resistance of the de-icing line before de-icing.

[0048] Obviously, according to The symbol can be used as a criterion for system stability under line resistance temperature drift. This indicates that the system is stable under temperature drift of the line resistance. This indicates system instability due to temperature drift in line resistance; therefore, stability criteria are crucial. Expand the analysis, based on The symbols can be discussed in the following two cases:

[0049] From the above equation, it can be seen that when the system becomes unstable due to temperature drift, Only the compensation coefficient needs to be selected. satisfy This will bring the system back to a stable state; and when the system stabilizes under temperature drift, Then you can choose to disconnect the current deviation compensation item of the host voltage command or select... satisfy The system remains stable.

[0050] In practical applications, if the control parameters can be adjusted online, the compensation coefficient can be set to the resistance of the de-icing circuit during de-icing. In this case, regardless of the temperature drift criterion... still The systems all run stably and require no further intervention. , Expand the design.

[0051] If the control parameters cannot be adjusted in real time, initial control parameters must be designed with a certain margin to cope with the instability risk caused by temperature drift of the line resistance. Therefore, this invention proposes a method for tuning the compensation coefficient under different scenarios based on the above control principle.

[0052] Specifically, this invention proposes a method for setting the control parameters of a DC ice-melting device based on two scenarios where the control parameters cannot be adjusted online.

[0053] 1) Scenario 1: For scenarios where resistance temperature drift is not significant If the system remains stable under temperature drift of the line resistance, then the compensation coefficient will be adjusted. By directly setting the resistance of the de-icing circuit to the resistance before de-icing, the stability condition can be naturally satisfied regardless of the original state of the system. This design approach greatly simplifies the parameter tuning process, eliminating the need to focus on the specific values ​​of the transformer turns ratio or to accurately calculate the integral coefficient. , The ratio between them is designed based on the resistance of the de-icing circuit before de-icing. , .

[0054] 2) Scenario Two: For scenarios with significant resistance temperature drift When the line resistance temperature drifts and the system becomes unstable, as the de-icing process progresses, the line temperature rises, leading to an increase in the resistance of the de-icing line. Transform into At this time, it will also be transferred to Transform into ,like Maintaining the initial values ​​will lead to system instability. Considering the cumbersome and difficult-to-implement nature of real-time parameter adjustments, a more robust design approach can be adopted. The system should be tuned based on the resistance of the de-icing circuit before de-icing. , At the same time, the compensation coefficient Set the resistance of the ice-melting circuit before ice melting.

[0055] The specific design principles are as follows:

[0056] In the formula, This represents the resistance of the de-icing circuit before de-icing.

[0057] Before the ice melts, the line temperature is low, and the line resistance is also low. As the ice melts, the line temperature rises, the line resistance increases, and it becomes greater than the resistance of the line before the ice melt. Designed using this method, the circuit resistance will always meet the required standards regardless of temperature drift. as well as It is easy to see that the system can maintain stable operation at this time.

[0058] Step 4: Based on the adjusted control parameters and compensation coefficients of the DC ice melting device, perform coordinated control between the master and slave devices.

[0059] The master unit performs constant DC voltage control based on the adjusted constant DC voltage control integral coefficient and compensation coefficient; the slave unit performs constant DC current control based on the adjusted constant DC current control integral coefficient.

[0060] This invention establishes an adaptive control strategy based on compensation coefficients: according to the adjustability of control parameters and the system stability criterion under temperature drift, the compensation coefficient is set to the measured value or preset value of the line resistance, and robust parameter tuning is used to ensure stability under all operating conditions when real-time adjustment is not possible.

[0061] After adopting the improved control strategy proposed in this invention, the design object is from , Two values ​​are reduced to one value It also has good adaptability to any transformer ratio.

[0062] To verify the effectiveness of this invention, a Matlab-Simulink simulation platform was used. First, a conventional control strategy was implemented, setting the transformer ratio connected to the master unit to 35:20 and the transformer ratio connected to the slave unit to 35:15, meaning the master unit's transformer ratio was higher than the slave unit's. The master unit's control parameters were maintained. =0.0002 remains unchanged, change the slave control parameter The simulation results are shown in Table 1.

[0063] Table 1. Flow sharing under different control parameters (master transformer ratio 35:20, slave transformer ratio 35:15)

[0064] As shown in Table 1, when the control parameters meet the stability criterion ( > When this happens, the system can maintain stable operation, and the current sharing between the master and slave machines is normal. Figure 4 The curves showing the change of master and slave currents with respect to time in scenario ① are shown. As... The current gradually decreases until it no longer meets the stability criterion, at which point the system becomes unstable, the slave current rapidly decays to zero, and the entire de-icing current is borne by the master unit. Figure 5 The curves showing the change of master and slave currents with respect to time in scenario ② are shown.

[0065] The method proposed in this invention involves superimposing a current deviation compensation term into the host voltage command. The transformer ratio connected to the host is set to 35:20, and the transformer ratio connected to the slave is set to 35:15. A compensation coefficient is then used. The value is 10, which represents the resistance of the de-icing circuit before de-icing. The simulation results are shown in Table 2.

[0066] Table 2. Flow equalization under the method proposed in this invention.

[0067] Comparing Table 2 and Table 1, the parameter combinations that result in flow sharing failure under the traditional control strategy are... =0.0002 and =0.003、 =0.0002 and =0.001, after applying the method proposed in this invention, stable operation will be restored, such as Figure 6 The curves showing the change of master and slave currents with respect to time in scenario ③ are shown.

[0068] The above results fully demonstrate the positive improvement effect on system stability after introducing the method proposed in this invention.

[0069] Another aspect of the present invention proposes a collaborative control system for a DC ice-melting device with parallel capacity expansion on the DC side of an LCC, comprising: The constraint condition establishment module is used to establish constraint conditions for the control parameters of the DC ice melting device that are stable before ice melting, based on the resistance of the ice melting line, the AC side voltage of the host and the AC side voltage of the slave. A compensation coefficient is introduced. During ice melting, the current difference between the slave DC side current and the host DC side current is multiplied by the compensation coefficient to obtain a current deviation compensation term, which is then superimposed on the host voltage command to obtain a new host voltage command. Using the compensation coefficient, based on the constraint conditions of the DC ice melting device control parameters that are stable before ice melting, constraint conditions of the DC ice melting device control parameters that are stable during ice melting are established. These constraint conditions include the system stability criterion under line resistance temperature drift during ice melting. The tuning module is used to tune the compensation coefficient and the control parameters of the DC de-icing device based on the adjustability of the control parameters and the system stability judgment results under the temperature drift of the line resistance. The master and slave units perform coordinated control based on the control parameters and compensation coefficients of the DC ice-melting device obtained through tuning.

[0070] This disclosure can be a system, method, and / or computer program product. A computer program product may include a computer-readable storage medium having computer-readable program instructions loaded thereon for causing a processor to implement various aspects of this disclosure.

[0071] Computer-readable storage media can be tangible devices capable of holding and storing instructions for use by an instruction execution device. Computer-readable storage media can be, for example—but not limited to—electrical storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of computer-readable storage media include: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disc read-only memory (CD-ROM), digital multifunction disc (DVD), memory sticks, floppy disks, mechanical encoding devices, such as punch cards or recessed protrusions storing instructions thereon, and any suitable combination of the foregoing. The computer-readable storage media used herein are not to be construed as transient signals themselves, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides or other transmission media (e.g., light pulses through fiber optic cables), or electrical signals transmitted through wires.

[0072] The computer-readable program instructions described herein can be downloaded from computer-readable storage media to various computing / processing devices, or downloaded via a network, such as the Internet, local area network, wide area network, and / or wireless network, to an external computer or external storage device. The network may include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards them to the computer-readable storage media in the respective computing / processing device.

[0073] Computer program instructions used to perform the operations of this disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, status setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk, C++, etc., and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The computer-readable program instructions may execute entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or may be connected to an external computer (e.g., via the Internet using an Internet service provider). In some embodiments, electronic circuitry, such as programmable logic circuitry, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), is personalized by utilizing the status information of the computer-readable program instructions to implement various aspects of this disclosure.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. A collaborative control method for a DC ice-melting device with parallel expansion of LCC DC side, wherein one LCC in the DC ice-melting device is the master unit, and the remaining LCCs are slave units, the master unit adopts constant DC voltage control, and the slave units adopt constant DC current control; characterized in that, include: Before de-icing, constraints are established on the control parameters of the DC de-icing device to ensure system stability before de-icing, based on the resistance of the de-icing line, the AC side voltage of the main unit, and the AC side voltage of the slave unit. A compensation coefficient is introduced. During ice melting, the current difference between the slave DC side current and the host DC side current is multiplied by the compensation coefficient to obtain a current deviation compensation term, which is then superimposed on the host voltage command to obtain a new host voltage command. Using the compensation coefficient, based on the constraint conditions of the DC ice melting device control parameters that are stable before ice melting, constraint conditions of the DC ice melting device control parameters that are stable during ice melting are established. These constraint conditions include the system stability criterion under line resistance temperature drift during ice melting. Based on the adjustability of the control parameters and the system stability judgment results under line resistance temperature drift, the compensation coefficient and the control parameters of the DC ice melting device are adjusted. Based on the control parameters and compensation coefficients of the DC ice-melting device obtained by tuning, the master and slave units perform coordinated control.

2. The collaborative control method for the DC ice-melting device with parallel expansion of the LCC DC side according to claim 1, characterized in that, The compensation coefficient and control parameters of the DC ice-melting device are tuned, including: If the control parameters can be adjusted online, the compensation coefficient is set to the resistance of the de-icing line during de-icing; if the control parameters cannot be adjusted online and the system is determined to be stable under temperature drift of the line resistance, the compensation coefficient is set only to the resistance of the de-icing line before de-icing; if the control parameters cannot be adjusted online and the system is determined to be unstable under temperature drift of the line resistance, the control parameters of the DC de-icing device are adjusted based on the resistance of the de-icing line before de-icing, and the compensation coefficient is set to the resistance of the de-icing line before de-icing.

3. The collaborative control method for the DC ice-melting device with parallel capacity expansion on the DC side of the LCC according to claim 1, characterized in that, The control parameters of the DC de-icing device include: the integral coefficient of the constant DC voltage control of the main unit and the integral coefficient of the constant DC current control of the slave unit.

4. The collaborative control method for the DC ice-melting device with parallel capacity expansion on the DC side of the LCC according to claim 3, characterized in that, Using the Hurwitz criterion, the constant DC voltage control constraints and constant DC current control constraints for system stability before ice melting are established as follows: In the formula, , , , These are the effective values ​​of the AC side voltages of the master and slave devices, respectively. , These are the integral coefficients for constant DC voltage control and constant DC current control, respectively. This represents the resistance of the de-icing circuit before de-icing.

5. The collaborative control method for the DC ice-melting device with parallel capacity expansion on the DC side of LCC according to claim 1, characterized in that, Slave DC side current DC side current of the host The current difference between them multiplied by the compensation coefficient Obtain the current deviation compensation term New host voltage command , This is the host voltage command.

6. The collaborative control method for the DC ice-melting device with parallel expansion of the LCC DC side according to claim 4, characterized in that, Based on the compensation coefficient, the constraints for updating the control parameters of the DC ice-melting device for system stability during ice melting are as follows: In the formula, This is the compensation coefficient.

7. The collaborative control method for the DC ice-melting device with parallel expansion of the LCC DC side according to claim 6, characterized in that, The constraints include system stability criteria under temperature drift of line resistance during de-icing. ; This indicates that the system is stable under temperature drift of the line resistance. This indicates system instability due to temperature drift in line resistance.

8. A collaborative control system for a DC-DC ice-melting device with parallel capacity expansion on the DC side of an LCC, used to implement the collaborative control method for the DC-DC ice-melting device with parallel capacity expansion on the DC side of an LCC as described in any one of claims 1 to 7, characterized in that, include: The constraint condition establishment module is used to establish constraint conditions for the control parameters of the DC ice melting device that are stable before ice melting, based on the resistance of the ice melting line, the AC side voltage of the host and the AC side voltage of the slave. A compensation coefficient is introduced. During ice melting, the current difference between the slave DC side current and the host DC side current is multiplied by the compensation coefficient to obtain a current deviation compensation term, which is then superimposed on the host voltage command to obtain a new host voltage command. Using the compensation coefficient, based on the constraint conditions of the DC ice melting device control parameters that are stable before ice melting, constraint conditions of the DC ice melting device control parameters that are stable during ice melting are established. These constraint conditions include the system stability criterion under line resistance temperature drift during ice melting. The tuning module is used to tune the compensation coefficient and the control parameters of the DC de-icing device based on the adjustability of the control parameters and the system stability judgment results under the temperature drift of the line resistance. The master and slave units perform coordinated control based on the control parameters and compensation coefficients of the DC ice-melting device obtained through tuning.

9. A terminal, comprising a processor and a storage medium; characterized in that: The storage medium is used to store instructions; The processor is configured to operate according to the instructions to perform the steps of the method according to any one of claims 1-7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the program implements the steps of the method according to any one of claims 1-7.

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