Building block type ice melting device active current sharing system and control method

Abstract

The invention relates to a building block type ice melting device active current sharing system and a control method, and the system comprises a plurality of ice melting rectification devices which are connected in parallel to a to-be-ice-melted line, and a bidirectional Buck-Boost current sharing module is connected in series between the DC output end of each ice melting rectification device and the to-be-ice-melted line; and the current sharing controller is used for collecting the output voltage value and the output current value of each ice-melting rectifying device in real time, judging whether the plurality of ice-melting rectifying devices share the current or not, calculating the current sharing control quantity and generating a compensation voltage instruction when the plurality of ice-melting rectifying devices do not share the current, and adjusting the corresponding bidirectional Buck-Boost current sharing module through the compensation voltage instruction, so that the plurality of ice-melting rectifying devices realize the current sharing. High-precision current sharing and effective circulating current suppression can be realized under the condition of not changing the structure of the existing main circuit, and the circuit is suitable for a large-capacity and multi-machine parallel mobile ice melting equipment scene and has a remarkable engineering application value.

Description

Technical Field

[0001] This invention belongs to the technical field of power transmission line de-icing equipment, and particularly relates to an active current equalization system and control method for a modular de-icing device. Background Technology

[0002] In transmission lines severely iced, high-power de-icing currents ranging from hundreds to thousands of amperes are commonly used in engineering to quickly melt the ice and suppress the risks of conductor galloping and flashover. To meet the de-icing needs of different line capacities, mobile de-icing devices can be connected in parallel to build "modular" expansion systems of 20MW, 60MW, or even 100MW, thus adapting to the operational requirements of lines with different voltage levels while achieving equipment standardization and cost savings. Existing parallel systems generally use diode rectifier topologies. Due to rectifier transformer turns ratio errors, internal impedance differences, and inconsistent diode device characteristics, the output DC voltage of different de-icing devices will have a fixed deviation. This deviation will cause uneven current distribution during parallel operation, leading to overload in some branches and inefficient operation in others. At the same time, voltage differences can also induce circulating currents, causing current to flow back between devices, affecting the safety of rectifier transformers and rectifier devices.

[0003] Existing technologies primarily reduce bias current by adjusting the voltage using on-load tap changers (OLTCs) or by using current-sharing reactors. However, OLTCs have long voltage adjustment steps and slow response, making them unsuitable for rapid dynamic current sharing. Current-sharing reactors are bulky and have high losses, making them unsuitable for mobile equipment. Furthermore, methods such as virtual impedance control mainly suppress dynamic circulating current but cannot compensate for static voltage differences, resulting in limited current sharing capabilities.

[0004] In summary, existing parallel de-icing devices generally suffer from technical bottlenecks such as the inability to eliminate bias current and circulating current caused by static pressure difference, insufficient dynamic current sharing capability, inadequate voltage regulation accuracy, high additional hardware costs, and excessive losses. There is an urgent need for a new solution that can achieve voltage fine-tuning, active current sharing control, and circulating current suppression without changing the main circuit topology, so as to ensure the safe, stable, and efficient operation of multiple de-icing devices in high-current de-icing scenarios. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides an active flow equalization system and control method for a modular ice-melting device.

[0006] The technical solution adopted in this invention is:

[0007] Firstly, an active flow equalization system for a modular ice-melting device is provided, comprising:

[0008] Multiple ice-melting rectifiers are connected in parallel to the line to be melted, and a bidirectional Buck-Boost current sharing module is connected in series between the DC output terminal of each ice-melting rectifier and the line to be melted.

[0009] The current sharing controller establishes a communication connection with all ice-melting rectifiers and bidirectional Buck-Boost current sharing modules;

[0010] The current sharing controller is used to collect the output voltage and output current values ​​of each ice-melting rectifier in real time, determine whether multiple ice-melting rectifiers are sharing the current, and when the current is not shared, calculate the current sharing control quantity and generate a compensation voltage command. The corresponding bidirectional Buck-Boost current sharing module is adjusted through the compensation voltage command to enable multiple ice-melting rectifiers to achieve current sharing.

[0011] Furthermore, the current sharing controller includes:

[0012] Data communication module, main ice melting rectifier selection module, data processing module and instruction sending module;

[0013] The main de-icing rectifier selection module is used to select one de-icing rectifier as the main de-icing rectifier and control the main de-icing rectifier to be in constant voltage mode, and apply the DC voltage value to both ends of the line to be de-iced as the port voltage value of the line to be de-iced.

[0014] The data communication module is used to collect the output voltage and output current values ​​of each ice-melting rectifier in real time;

[0015] The data processing module is used to calculate the average current value of the output current values ​​of all ice-melting rectifiers, and to determine whether the multiple ice-melting rectifiers share the current based on the average current value; when the current is not shared, the current sharing control quantity is calculated and a compensation voltage command is generated.

[0016] The instruction sending module is used to send compensation voltage instructions to the corresponding bidirectional Buck-Boost current sharing module, so that multiple ice melting rectifiers can achieve current sharing.

[0017] Furthermore, the data processing module includes:

[0018] The average current calculation unit is used to input the output current values ​​of all ice-melting rectifiers into the average current calculation formula to obtain the average current value.

[0019] The current sharing judgment unit is used to subtract the average current value from the output current value of each ice-melting rectifier to calculate the current sharing error; it judges whether the current sharing error is 0. When the current sharing error is equal to 0, the corresponding ice-melting rectifier is determined to be current sharing; when the current sharing error is greater than or less than 0, the corresponding ice-melting rectifier is determined to be non-current sharing.

[0020] The flow equalization control calculation unit is used to input the flow equalization error of the uneven flow ice melting rectifier into the duty cycle adjustment calculation formula to obtain the duty cycle adjustment amount;

[0021] The instruction generation unit is used to generate compensation voltage instructions by using the duty cycle adjustment amount as the current sharing control amount.

[0022] Furthermore, the expression for the average current calculation formula is as follows:

[0023] ;

[0024] in, This represents the average current value, and N represents the total number of ice-melting rectifier devices. This represents the output current value of the i-th ice-melting rectifier;

[0025] The expression for the duty cycle adjustment calculation formula is:

[0026] ;

[0027] in, This represents the duty cycle adjustment amount of the initial duty cycle D of the bidirectional Buck-Boost current sharing module corresponding to the i-th ice-melting rectifier. and These are preset fixed parameters.

[0028] Furthermore, the bidirectional Buck-Boost current sharing module includes:

[0029] The input-side DC support capacitor C1, the switching power device Q1, the switching power device Q2, the energy coupling inductor L1, and the output-side DC support capacitor C2 form a bidirectional Buck-Boost circuit structure.

[0030] When the current sharing error of the target ice-melting rectifier is less than 0, the duty cycle adjustment amount in the compensation voltage command sent by the command sending module is adjusted accordingly. The initial duty cycle D is adjusted to control the bidirectional Buck-Boost circuit structure to switch to Boost mode, thereby increasing the equivalent output voltage of the target ice-melting rectifier and making the current sharing error of the target ice-melting rectifier zero.

[0031] When the current sharing error of the target ice-melting rectifier is greater than 0, the duty cycle adjustment amount in the compensation voltage command sent by the command sending module is adjusted accordingly. The initial duty cycle D is adjusted to control the bidirectional Buck-Boost circuit structure to switch to Buck mode, thereby reducing the equivalent output voltage of the target ice-melting rectifier and making the current sharing error of the target ice-melting rectifier zero.

[0032] Secondly, an active flow sharing control method for a modular ice-melting device is provided, applied to the active flow sharing system of the modular ice-melting device. The active flow sharing system of the modular ice-melting device includes multiple ice-melting rectifiers, multiple bidirectional Buck-Boost flow sharing modules, and a flow sharing controller. The method includes:

[0033] Multiple ice-melting rectifiers are connected in parallel to the line to be melted. A bidirectional Buck-Boost current sharing module is connected in series between the DC output terminal of each ice-melting rectifier and the line to be melted. The current sharing controller establishes a communication connection with all the ice-melting rectifiers and the bidirectional Buck-Boost current sharing module.

[0034] The current sharing controller collects the output voltage and current values ​​of each ice-melting rectifier in real time, determines whether the multiple ice-melting rectifiers are sharing the current, and calculates the current sharing control quantity and generates a compensation voltage command when the current is not sharing the current. The corresponding bidirectional Buck-Boost current sharing module is adjusted through the compensation voltage command to enable the multiple ice-melting rectifiers to achieve current sharing.

[0035] Furthermore, the current sharing controller collects the output voltage and current values ​​of each ice-melting rectifier in real time to determine whether the multiple ice-melting rectifiers are sharing the current. When the current is not sharing the current, it calculates the current sharing control quantity and generates a compensation voltage command. The compensation voltage command is used to adjust the corresponding bidirectional Buck-Boost current sharing module to enable the multiple ice-melting rectifiers to achieve current sharing, including:

[0036] The current sharing controller selects an ice-melting rectifier as the main ice-melting rectifier and controls the main ice-melting rectifier to be in constant voltage mode. The DC voltage applied to both ends of the line to be melted is used as the port voltage of the line to be melted.

[0037] Real-time acquisition of the output voltage and output current values ​​of each ice-melting rectifier;

[0038] Calculate the average current value of the output current values ​​of all ice-melting rectifiers, and determine whether the multiple ice-melting rectifiers share the current based on the average current value; if the current is not shared, calculate the current sharing control quantity and generate a compensation voltage command.

[0039] The compensation voltage command is sent to the corresponding bidirectional Buck-Boost current sharing module, enabling multiple ice-melting rectifiers to achieve current sharing.

[0040] Furthermore, the average current value of the output current of all ice-melting rectifiers is calculated, and the average current value is used to determine whether the multiple ice-melting rectifiers share the current. If the current is not shared, the current sharing control quantity is calculated and a compensation voltage command is generated, including:

[0041] Input the output current values ​​of all ice-melting rectifiers into the average current calculation formula to obtain the average current value;

[0042] The average current value is subtracted from the output current value of each ice-melting rectifier to calculate the current sharing error. It is then determined whether the current sharing error is 0. If the current sharing error is equal to 0, the corresponding ice-melting rectifier is determined to be current sharing; if the current sharing error is greater than or less than 0, the corresponding ice-melting rectifier is determined to be non-current sharing.

[0043] The flow equalization error of the uneven flow de-icing rectifier is input into the duty cycle adjustment calculation formula to obtain the duty cycle adjustment amount;

[0044] The duty cycle adjustment is used as the current sharing control quantity to generate the compensation voltage command.

[0045] Furthermore, the expression for the average current calculation formula is as follows:

[0046] ;

[0047] in, This represents the average current value, and N represents the total number of ice-melting rectifier devices. This represents the output current value of the i-th ice-melting rectifier;

[0048] The expression for the duty cycle adjustment calculation formula is:

[0049] ;

[0050] in, This represents the duty cycle adjustment amount of the initial duty cycle D of the bidirectional Buck-Boost current sharing module corresponding to the i-th ice-melting rectifier. and These are preset fixed parameters.

[0051] Furthermore, the bidirectional Buck-Boost current sharing module includes an input-side DC support capacitor C1, a switching power device Q1, a switching power device Q2, an energy coupling inductor L1, and an output-side DC support capacitor C2, forming a bidirectional Buck-Boost circuit structure.

[0052] The method of adjusting the corresponding bidirectional Buck-Boost current sharing module through compensation voltage commands to enable current sharing among multiple ice-melting rectifiers includes:

[0053] When the current sharing error of the target ice-melting rectifier is less than 0, the duty cycle adjustment amount in the compensation voltage command is used. The initial duty cycle D is adjusted to control the bidirectional Buck-Boost circuit structure to switch to Boost mode, thereby increasing the equivalent output voltage of the target ice-melting rectifier and making the current sharing error of the target ice-melting rectifier zero.

[0054] When the current sharing error of the target ice-melting rectifier is greater than 0, the duty cycle adjustment amount in the compensation voltage command shall apply. The initial duty cycle D is adjusted to control the bidirectional Buck-Boost circuit structure to switch to Buck mode, thereby reducing the equivalent output voltage of the target ice-melting rectifier and making the current sharing error of the target ice-melting rectifier zero.

[0055] The beneficial effects achieved by this invention are as follows:

[0056] Multiple ice-melting rectifiers are connected in parallel to the line to be melted. A bidirectional Buck-Boost current sharing module is connected in series between the DC output terminal of each ice-melting rectifier and the line to be melted. The current sharing controller establishes a communication connection with all ice-melting rectifiers and the bidirectional Buck-Boost current sharing module. The current sharing controller collects the output voltage and output current values ​​of each ice-melting rectifier in real time, determines whether the multiple ice-melting rectifiers are sharing the current, and calculates the current sharing control quantity and generates a compensation voltage command when the current is not shared. The corresponding bidirectional Buck-Boost current sharing module is adjusted through the compensation voltage command to enable the multiple ice-melting rectifiers to achieve current sharing.

[0057] The bidirectional Buck-Boost current sharing module provides precise voltage compensation and achieves accurate current sharing through closed-loop control. It can stably control the current deviation to below 1%, which is far superior to traditional OLTC voltage regulators or current sharing reactors.

[0058] No need to change the main rectifier circuit of the ice-melting rectifier device, it does not affect the high-current main circuit of ice melting, it is easy to install and modify, and has strong compatibility.

[0059] The bidirectional Buck-Boost current sharing module has the characteristics of low power and small size. It can be modularly connected to existing ice melting devices, and its overall cost is far lower than that of OLTC or high-power current sharing reactors.

[0060] It can simultaneously and accurately compensate for static voltage differences and suppress high-frequency dynamic circulating current, which is something that traditional current sharing strategies cannot achieve at the same time.

[0061] It is suitable for "modular" expansion architecture, which can flexibly expand multiple ice melting devices in the mode of 20MW→60MW→100MW, which is safe and reliable;

[0062] In summary, this invention can achieve high-precision current sharing and effective circulating current suppression without changing the existing main circuit structure. It is suitable for large-capacity, multi-machine parallel mobile ice melting equipment scenarios and has significant engineering application value. Attached Figure Description

[0063] Figure 1 This is a structural diagram of the active flow equalization system of the modular ice-melting device of the present invention;

[0064] Figure 2 This is a structural diagram of the current sharing controller of the present invention;

[0065] Figure 3 This is a structural diagram of the data processing module of the present invention;

[0066] Figure 4 This is a circuit diagram of the bidirectional Buck-Boost current sharing module of the present invention;

[0067] Figure 5 This is a flowchart of the active flow equalization control method for the modular ice melting device of the present invention. Detailed Implementation

[0068] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0069] like Figure 1 As shown, this embodiment of the invention provides an active flow equalization system for a modular ice-melting device, comprising:

[0070] Multiple de-icing rectifiers 101 (de-icing rectifier 1-de-icing rectifier N) are connected in parallel to the line to be de-iced. Specifically, the two DC output terminals of the de-icing rectifier 101 are connected to the two ends of the load of the line to be de-iced, respectively. It should be noted that, for ease of implementation, the de-icing rectifier 101 can be mobile. The de-icing rectifier 101 includes a de-icing transformer, a rectifier, and a combined disconnect switch. According to the existing method, the input terminal of the de-icing rectifier 101 needs to be connected to the 10kV busbar through a cable branch box and a circuit breaker.

[0071] A bidirectional Buck-Boost current sharing module 102 (bidirectional Buck-Boost current sharing module 1-bidirectional Buck-Boost current sharing module N) is connected in series between the DC output terminal of each ice-melting rectifier 101 and the line to be melted.

[0072] The flow equalization controller 103 establishes a communication connection with all the ice melting rectifiers 101 and the bidirectional Buck-Boost flow equalization module 102;

[0073] The current sharing controller 103 is used to collect the output voltage and output current values ​​of each ice-melting rectifier 101 in real time, determine whether the multiple ice-melting rectifiers 101 are sharing the current, and when the current is not sharing the current, calculate the current sharing control quantity and generate a compensation voltage command. The corresponding bidirectional Buck-Boost current sharing module 102 is adjusted through the compensation voltage command so that the multiple ice-melting rectifiers 101 can achieve current sharing.

[0074] Combination Figure 1The embodiments shown are preferred embodiments of the present invention, such as... Figure 2 As shown, the current sharing controller 103 includes:

[0075] Data communication module 201, data processing module 202, instruction sending module 203 and main ice melting rectifier selection module 204;

[0076] The main de-icing rectifier selection module 204 is used to select a de-icing rectifier as the main de-icing rectifier and control the main de-icing rectifier to be in constant voltage mode. The DC voltage applied to both ends of the line to be de-iced is used as the port voltage value of the line to be de-iced. Specifically, the de-icing rectifier with the largest capacity or the de-icing rectifier with the smallest preset number can be selected as the main de-icing rectifier. The constant voltage mode of the main de-icing rectifier is to maintain the DC voltage applied to both ends of the line to be de-iced within the set reference value range, such as 10000V. Other de-icing rectifiers are subordinate and will not participate in the adjustment of the port voltage value of the line to be de-iced.

[0077] Data communication module 201 is used to collect the output voltage and output current values ​​of each ice-melting rectifier in real time;

[0078] Data processing module 202 is used to calculate the average current value of the output current values ​​of all ice-melting rectifiers, and to determine whether multiple ice-melting rectifiers share the current based on the average current value; when the current is not shared, it calculates the current sharing control quantity and generates a compensation voltage command.

[0079] The instruction sending module 203 is used to send the compensation voltage instruction to the corresponding bidirectional Buck-Boost current sharing module, so that multiple ice melting rectifiers can achieve current sharing.

[0080] Combination Figure 1 The embodiments shown are preferred embodiments of the present invention, such as... Figure 3 As shown, the data processing module 202 includes:

[0081] The average current calculation unit 301 is used to input the output current values ​​of all ice-melting rectifiers into the average current calculation formula to obtain the average current value.

[0082] The expression for the average current calculation formula is:

[0083] ;

[0084] in, This represents the average current value, and N represents the total number of ice-melting rectifier devices. This represents the output current value of the i-th ice-melting rectifier;

[0085] The current sharing judgment unit 302 is used to subtract the average current value from the output current value of each ice-melting rectifier to calculate the current sharing error. Determine if the current sharing error is 0. If the current sharing error is equal to 0, determine that the corresponding ice-melting rectifier is a current sharing device; if the current sharing error is greater than or less than 0, determine that the corresponding ice-melting rectifier is not a current sharing device.

[0086] The flow equalization control calculation unit 303 is used to input the flow equalization error of the uneven flow ice melting rectifier into the duty cycle adjustment calculation formula to obtain the duty cycle adjustment amount;

[0087] The expression for the duty cycle adjustment calculation formula is:

[0088] ;

[0089] in, This represents the duty cycle adjustment amount of the initial duty cycle D of the bidirectional Buck-Boost current sharing module corresponding to the i-th ice-melting rectifier. and These are preset fixed parameters.

[0090] The instruction generation unit 304 is used to generate a compensation voltage instruction by using the duty cycle adjustment amount as the current sharing control amount.

[0091] like Figure 4 As shown, the bidirectional Buck-Boost current sharing module includes:

[0092] The input-side DC support capacitor C1, switching power devices Q1 and Q2, energy coupling inductor L1, and output-side DC support capacitor C2, with Q1 and Q2 specifically being IGBTs, form a bidirectional Buck-Boost circuit structure. This allows for voltage difference adjustment in both directions. The principle is as follows:

[0093] When the DC bus voltage is too low or the current is too small, and the current needs to be increased, Buck-Boost enters Boost mode (i.e., voltage boosting); when the DC bus voltage is too high or the current is too large, and the current needs to be reduced, Buck-Boost enters Buck mode (i.e., voltage bucking).

[0094] The equivalent output voltage applied to the circuit to be melted after adjustment by the bidirectional Buck-Boost current sharing module is V. o Equivalent output voltage value V o The expression is:

[0095] ;

[0096] Among them, V inLet be the DC output voltage value of a certain ice-melting rectifier, and D be the initial duty cycle of the corresponding bidirectional Buck-Boost current sharing module;

[0097] By adjusting the initial duty cycle D, the voltage difference between the de-icing branch and the line to be de-iced can be changed, thereby adjusting the DC current value. DC current value Represented as:

[0098] ;

[0099] in, The voltage value at the port of the line to be de-iced is given above. It is known because the main de-icing rectifier selection module 204 selects the main de-icing rectifier; Given the equivalent DC impedance value, which is also known, then in order to adjust the DC current value... The size of the voltage can only be adjusted by adjusting the equivalent output voltage value V. o That is, the adjustment formula D in the middle.

[0100] When the current sharing error of the target ice-melting rectifier is less than 0, the duty cycle adjustment amount in the compensation voltage command sent by the command sending module is adjusted accordingly. Adjusting the initial duty cycle D controls the bidirectional Buck-Boost circuit structure to switch to Boost mode, thereby increasing the equivalent output voltage V of the target ice-melting rectifier. o This makes the DC current value of the target ice-melting rectifier device... Increase appropriately until the flow equalization error =0;

[0101] When the current sharing error of the target ice-melting rectifier is greater than 0, the duty cycle adjustment amount in the compensation voltage command sent by the command sending module is adjusted accordingly. Adjusting the initial duty cycle D controls the bidirectional Buck-Boost circuit structure to switch to Buck mode, thereby reducing the equivalent output voltage V of the target ice-melting rectifier. o This makes the DC current value of the target ice-melting rectifier device... Reduce appropriately until the flow equalization error is reached. It is 0.

[0102] It should be noted that when the current sharing controller detects a high-frequency circulating current, it can adjust the current of its internal energy coupling inductor L1 by controlling the bidirectional Buck-Boost current sharing module, thereby increasing the equivalent damping and suppressing the high-frequency circulating current.

[0103] The beneficial effects achieved by the embodiments of the present invention are as follows:

[0104] The bidirectional Buck-Boost current sharing module provides precise voltage compensation and achieves accurate current sharing through closed-loop control. It can stably control the current deviation to below 1%, which is far superior to traditional OLTC voltage regulators or current sharing reactors.

[0105] No need to change the main rectifier circuit of the ice-melting rectifier device, it does not affect the high-current main circuit of ice melting, it is easy to install and modify, and has strong compatibility.

[0106] The bidirectional Buck-Boost current sharing module has the characteristics of low power and small size. It can be modularly connected to existing ice melting devices, and its overall cost is far lower than that of OLTC or high-power current sharing reactors.

[0107] It can simultaneously and accurately compensate for static voltage differences and suppress high-frequency dynamic circulating current, which is something that traditional current sharing strategies cannot achieve at the same time.

[0108] It is suitable for "modular" expansion architecture, which can flexibly expand multiple ice melting devices in the mode of 20MW→60MW→100MW, which is safe and reliable;

[0109] In summary, it can achieve high-precision current sharing and effective circulating current suppression without changing the existing main circuit structure, making it suitable for large-capacity, multi-unit parallel mobile ice melting equipment scenarios and possessing significant engineering application value.

[0110] Based on the active flow equalization system of the modular ice-melting device described in the above embodiments, the active flow equalization control method of the modular ice-melting device will be explained below through embodiments.

[0111] In summary Figure 1 The present invention provides an active flow equalization control method for a modular ice-melting device, comprising:

[0112] Multiple ice-melting rectifiers are connected in parallel to the line to be melted. A bidirectional Buck-Boost current sharing module is connected in series between the DC output terminal of each ice-melting rectifier and the line to be melted. The current sharing controller establishes a communication connection with all the ice-melting rectifiers and the bidirectional Buck-Boost current sharing module.

[0113] The current sharing controller collects the output voltage and current values ​​of each ice-melting rectifier in real time, determines whether the multiple ice-melting rectifiers are sharing the current, and calculates the current sharing control quantity and generates a compensation voltage command when the current is not sharing the current. The corresponding bidirectional Buck-Boost current sharing module is adjusted through the compensation voltage command to enable the multiple ice-melting rectifiers to achieve current sharing.

[0114] Specifically, the implementation process of the active flow equalization control method for the modular ice melting device is as follows: Figure 5 As shown, it includes:

[0115] 501. Connect multiple de-icing rectifiers in parallel to the line to be de-iced;

[0116] For example, three mobile ice-melting rectifiers are connected in parallel to the line to be melted; then a bidirectional Buck-Boost current sharing module is connected in series to the DC output terminal of each ice-melting rectifier; the current sharing controller also needs to establish a communication connection with the current and voltage sampling devices deployed on the ice-melting rectifiers and the bidirectional Buck-Boost current sharing module to read the output voltage value of the ice-melting rectifiers when they are unloaded and complete the parameter initialization.

[0117] 502, the current sharing controller selects an ice-melting rectifier as the main ice-melting rectifier and controls the main ice-melting rectifier to be in constant voltage mode, and applies the DC voltage value to both ends of the line to be melted as the port voltage value of the line to be melted.

[0118] Select the ice-melting rectifier with the largest capacity or the ice-melting rectifier with the smallest preset number as the main ice-melting rectifier. The constant voltage mode of the main ice-melting rectifier is to maintain the DC voltage applied to both ends of the line to be melted within the set reference value range, such as 10000V. Other ice-melting rectifiers are subordinate and will not participate in the adjustment of the voltage value at the port of the line to be melted.

[0119] 503, Real-time acquisition of the output voltage and output current values ​​of each ice-melting rectifier;

[0120] 504. Calculate the average current value of the output current values ​​of all ice-melting rectifiers, and determine whether the multiple ice-melting rectifiers have equal current based on the average current value.

[0121] Output current values ​​of all ice-melting rectifiers Input average current calculation formula The average current value was calculated. ;

[0122] The current sharing error is calculated by subtracting the average current value from the output current value of each ice-melting rectifier. Determine if the current sharing error is 0. If the current sharing error is equal to 0, determine that the corresponding ice-melting rectifier is a current sharing device. If the current sharing error is greater than or less than 0, determine that the corresponding ice-melting rectifier is not a current sharing device, and proceed to step 505.

[0123] 505, calculate the current sharing control quantity and generate the compensation voltage command;

[0124] The uneven flow ice melting rectifier's flow equalization error Input duty cycle adjustment calculation formula The duty cycle adjustment amount is obtained. ;

[0125] Adjust the duty cycle As a current sharing control quantity, it forms a command to generate compensation voltage.

[0126] 506 sends the compensation voltage command to the corresponding bidirectional Buck-Boost current sharing module, enabling multiple ice-melting rectifiers to achieve current sharing.

[0127] After receiving the compensation voltage command, the bidirectional Buck-Boost current sharing module parses and obtains the duty cycle adjustment amount. This adjusts the initial duty cycle D.

[0128] When the current sharing error of the target ice-melting rectifier is less than 0, the duty cycle adjustment amount in the compensation voltage command sent by the command sending module is adjusted accordingly. Adjusting the initial duty cycle D controls the bidirectional Buck-Boost circuit structure to switch to Boost mode, thereby increasing the equivalent output voltage V of the target ice-melting rectifier. o This makes the DC current value of the target ice-melting rectifier device... Increase appropriately until the flow equalization error =0;

[0129] When the current sharing error of the target ice-melting rectifier is greater than 0, the duty cycle adjustment amount in the compensation voltage command sent by the command sending module is adjusted accordingly. Adjusting the initial duty cycle D controls the bidirectional Buck-Boost circuit structure to switch to Buck mode, thereby reducing the equivalent output voltage V of the target ice-melting rectifier. o This makes the DC current value of the target ice-melting rectifier device... Reduce appropriately until the flow equalization error is reached. It is 0.

[0130] After multiple adjustments, the output current values ​​of all the ice-melting rectifiers are finally equal, and the deviation can generally be controlled within ±1%.

[0131] When the ice thickness of the circuit to be melted changes or the output characteristics of a certain ice-melting rectifier change due to temperature rise, the Buck-Boost module will continuously adjust the duty cycle to maintain a uniform current state.

[0132] The beneficial effects achieved by the embodiments of the present invention are as follows:

[0133] The bidirectional Buck-Boost current sharing module provides precise voltage compensation and achieves accurate current sharing through closed-loop control. It can stably control the current deviation to below 1%, which is far superior to traditional OLTC voltage regulators or current sharing reactors.

[0134] No need to change the main rectifier circuit of the ice-melting rectifier device, it does not affect the high-current main circuit of ice melting, it is easy to install and modify, and has strong compatibility.

[0135] The bidirectional Buck-Boost current sharing module has the characteristics of low power and small size. It can be modularly connected to existing ice melting devices, and its overall cost is far lower than that of OLTC or high-power current sharing reactors.

[0136] It can simultaneously and accurately compensate for static voltage differences and suppress high-frequency dynamic circulating current, which is something that traditional current sharing strategies cannot achieve at the same time.

[0137] It is suitable for "modular" expansion architecture, which can flexibly expand multiple ice melting devices in the mode of 20MW→60MW→100MW, which is safe and reliable;

[0138] In summary, it can achieve high-precision current sharing and effective circulating current suppression without changing the existing main circuit structure, making it suitable for large-capacity, multi-unit parallel mobile ice melting equipment scenarios and possessing significant engineering application value.

[0139] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied 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.

[0140] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. 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 illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0141] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0142] 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.

[0143] The above are merely embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of the claims of the present invention pending approval.

Claims

1. An active flow equalization system for a modular ice-melting device, characterized in that, include: Multiple ice-melting rectifiers are connected in parallel to the line to be melted, and a bidirectional Buck-Boost current sharing module is connected in series between the DC output terminal of each ice-melting rectifier and the line to be melted. The current sharing controller establishes a communication connection with all ice-melting rectifiers and bidirectional Buck-Boost current sharing modules; The current sharing controller is used to collect the output voltage and output current values ​​of each ice-melting rectifier in real time, determine whether multiple ice-melting rectifiers are sharing the current, and when the current is not shared, calculate the current sharing control quantity and generate a compensation voltage command. The corresponding bidirectional Buck-Boost current sharing module is adjusted through the compensation voltage command to enable multiple ice-melting rectifiers to achieve current sharing.

2. The active flow equalization system of the modular ice-melting device according to claim 1, characterized in that, The current sharing controller includes: Data communication module, main ice melting rectifier selection module, data processing module and instruction sending module; The main de-icing rectifier selection module is used to select one de-icing rectifier as the main de-icing rectifier and control the main de-icing rectifier to be in constant voltage mode, and apply the DC voltage value to both ends of the line to be de-iced as the port voltage value of the line to be de-iced. The data communication module is used to collect the output voltage and output current values ​​of each ice-melting rectifier in real time; The data processing module is used to calculate the average current value of the output current values ​​of all ice-melting rectifiers, and to determine whether the auxiliary ice-melting rectifiers are current-equalized based on the average current value; when the current is not equalized, the current-equalization control quantity is calculated and a compensation voltage command is generated. The instruction sending module is used to send the compensation voltage instruction to the corresponding bidirectional Buck-Boost current sharing module, so that all ice melting rectifiers can achieve current sharing.

3. The active flow equalization system of the modular ice-melting device according to claim 2, characterized in that, The data processing module includes: The average current calculation unit is used to input the output current values ​​of all ice-melting rectifiers into the average current calculation formula to obtain the average current value. The current sharing judgment unit is used to subtract the average current value from the output current value of each ice-melting rectifier to calculate the current sharing error; it judges whether the current sharing error is 0. When the current sharing error is equal to 0, the corresponding ice-melting rectifier is determined to be current sharing; when the current sharing error is greater than or less than 0, the corresponding ice-melting rectifier is determined to be non-current sharing. The flow equalization control calculation unit is used to input the flow equalization error of the uneven flow ice melting rectifier into the duty cycle adjustment calculation formula to obtain the duty cycle adjustment amount; The instruction generation unit is used to generate compensation voltage instructions by using the duty cycle adjustment amount as the current sharing control amount.

4. The active flow equalization system of the modular ice-melting device according to claim 3, characterized in that, The expression for the average current calculation formula is: ； in, This represents the average current value, and N represents the total number of ice-melting rectifier devices. This represents the output current value of the i-th ice-melting rectifier; The expression for the duty cycle adjustment calculation formula is: ； in, This represents the duty cycle adjustment amount of the initial duty cycle D of the bidirectional Buck-Boost current sharing module corresponding to the i-th ice-melting rectifier. and These are preset fixed parameters.

5. The active flow equalization system of the modular ice-melting device according to claim 4, characterized in that, The bidirectional Buck-Boost current sharing module includes: The input-side DC support capacitor C1, the switching power device Q1, the switching power device Q2, the energy coupling inductor L1, and the output-side DC support capacitor C2 form a bidirectional Buck-Boost circuit structure. When the current sharing error of the target ice-melting rectifier is less than 0, the duty cycle adjustment amount in the compensation voltage command sent by the command sending module is adjusted accordingly. The initial duty cycle D is adjusted to control the bidirectional Buck-Boost circuit structure to switch to Boost mode, thereby increasing the equivalent output voltage of the target ice-melting rectifier and making the current sharing error of the target ice-melting rectifier zero. When the current sharing error of the target ice-melting rectifier is greater than 0, the duty cycle adjustment amount in the compensation voltage command sent by the command sending module is adjusted accordingly. The initial duty cycle D is adjusted to control the bidirectional Buck-Boost circuit structure to switch to Buck mode, thereby reducing the equivalent output voltage of the target ice-melting rectifier and making the current sharing error of the target ice-melting rectifier zero.

6. An active flow equalization control method for a modular ice-melting device, characterized in that, This method is applied to the active flow equalization system of a modular ice-melting device. The active flow equalization system includes multiple ice-melting rectifiers, multiple bidirectional Buck-Boost flow equalization modules, and a flow equalization controller. Multiple ice-melting rectifiers are connected in parallel to the line to be melted. A bidirectional Buck-Boost current sharing module is connected in series between the DC output terminal of each ice-melting rectifier and the line to be melted. The current sharing controller establishes a communication connection with all the ice-melting rectifiers and the bidirectional Buck-Boost current sharing module. The current sharing controller collects the output voltage and current values ​​of each ice-melting rectifier in real time, determines whether the multiple ice-melting rectifiers are sharing the current, and calculates the current sharing control quantity and generates a compensation voltage command when the current is not sharing the current. The corresponding bidirectional Buck-Boost current sharing module is adjusted through the compensation voltage command to enable the multiple ice-melting rectifiers to achieve current sharing.

7. The active flow equalization control method for the modular ice-melting device according to claim 6, characterized in that, The current sharing controller collects the output voltage and current values ​​of each ice-melting rectifier in real time, determines whether the multiple ice-melting rectifiers are sharing the current, and calculates the current sharing control quantity and generates a compensation voltage command when the current is not shared. The compensation voltage command is used to adjust the corresponding bidirectional Buck-Boost current sharing module to achieve current sharing among the multiple ice-melting rectifiers, including: The current sharing controller selects an ice-melting rectifier as the main ice-melting rectifier and controls the main ice-melting rectifier to be in constant voltage mode. The DC voltage applied to both ends of the line to be melted is used as the port voltage of the line to be melted. Real-time acquisition of the output voltage and output current values ​​of each ice-melting rectifier; Calculate the average current value of the output current values ​​of all ice-melting rectifiers, and determine whether the multiple ice-melting rectifiers share the current based on the average current value; if the current is not shared, calculate the current sharing control quantity and generate a compensation voltage command. The compensation voltage command is sent to the corresponding bidirectional Buck-Boost current sharing module, enabling multiple ice-melting rectifiers to achieve current sharing.

8. The active flow equalization control method for the modular ice-melting device according to claim 7, characterized in that, Calculate the average current value of the output current values ​​of all ice-melting rectifiers, and determine whether the multiple ice-melting rectifiers share the current based on the average current value. When there is current imbalance, calculate the current sharing control quantity and generate a compensation voltage command, including: Input the output current values ​​of all ice-melting rectifiers into the average current calculation formula to obtain the average current value; The average current value is subtracted from the output current value of each ice-melting rectifier to calculate the current sharing error. It is then determined whether the current sharing error is 0. If the current sharing error is equal to 0, the corresponding ice-melting rectifier is determined to be current sharing; if the current sharing error is greater than or less than 0, the corresponding ice-melting rectifier is determined to be non-current sharing. The flow equalization error of the uneven flow de-icing rectifier is input into the duty cycle adjustment calculation formula to obtain the duty cycle adjustment amount; The duty cycle adjustment is used as the current sharing control quantity to generate the compensation voltage command.

9. The active flow equalization control method for the modular ice-melting device according to claim 8, characterized in that, The expression for the average current calculation formula is: ； in, This represents the average current value, and N represents the total number of ice-melting rectifier devices. This represents the output current value of the i-th ice-melting rectifier; The expression for the duty cycle adjustment calculation formula is: ； in, This represents the duty cycle adjustment amount of the initial duty cycle D of the bidirectional Buck-Boost current sharing module corresponding to the i-th ice-melting rectifier. and These are preset fixed parameters.

10. The active flow equalization control method for the modular ice-melting device according to claim 9, characterized in that, The bidirectional Buck-Boost current sharing module includes an input-side DC support capacitor C1, a switching power device Q1, a switching power device Q2, an energy coupling inductor L1, and an output-side DC support capacitor C2, forming a bidirectional Buck-Boost circuit structure. The method of adjusting the corresponding bidirectional Buck-Boost current sharing module through compensation voltage commands to enable current sharing among multiple ice-melting rectifiers includes: When the current sharing error of the target ice-melting rectifier is less than 0, the duty cycle adjustment amount in the compensation voltage command is used. The initial duty cycle D is adjusted to control the bidirectional Buck-Boost circuit structure to switch to Boost mode, thereby increasing the equivalent output voltage of the target ice-melting rectifier and making the current sharing error of the target ice-melting rectifier zero. When the current sharing error of the target ice-melting rectifier is greater than 0, the duty cycle adjustment amount in the compensation voltage command shall apply. The initial duty cycle D is adjusted to control the bidirectional Buck-Boost circuit structure to switch to Buck mode, thereby reducing the equivalent output voltage of the target ice-melting rectifier and making the current sharing error of the target ice-melting rectifier zero.

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