A Dandelion-Type Distribution Network Communication and Control Method

Abstract

This invention proposes a communication and control method for a dandelion-type power distribution network. The power distribution network includes one or more power supply units. Each power supply unit includes a low-voltage DC power network and multiple seed power supply units. Each seed power supply unit includes a low-voltage AC / DC converter, the power transmission end of which is connected to the power receiving end of a low-voltage distribution area. The low-voltage DC power network of the power supply unit is connected to a medium-voltage DC power network. The medium-voltage DC power network is connected to a medium-voltage AC power network. The power supply units communicate using power line carrier, micro-power, or multi-mode communication. Their DC side employs DC droop control to achieve self-organizing networks among the seed power supply units. The medium-voltage AC power network communicates using DC power line carrier, fiber optic, 4G, or 5G communication methods to achieve power balance control, coordinated operation, and flexible self-organizing networks in the power distribution network. This invention enables power balance control, coordinated operation, and flexible self-organizing networks in a dandelion-type power distribution network, improving the practicality of this type of power distribution network.

Description

Technical Field

[0001] This invention relates to the field of intelligent power distribution technology, and in particular to a dandelion-type power distribution network communication and control method. Background Technology

[0002] The rapid development of distributed renewable energy sources poses challenges to the power supply capacity, power quality, and resource carrying capacity of traditional AC distribution networks. Distributed renewable energy sources exhibit significant DC characteristics, making the construction of DC power supply and distribution systems a future trend. Compared to traditional AC distribution systems, DC distribution systems offer a range of advantages, including no phase requirements, large power supply capacity, low line losses, high energy transmission efficiency, good power quality, high power supply reliability, and suitability for renewable energy integration. Currently, hybrid AC / DC distribution systems are an effective solution for addressing traditional AC issues and constructing DC power supply and distribution systems, while significantly improving the power supply capacity and reliability of distribution areas.

[0003] Current AC / DC hybrid distribution systems mainly include flexible DC interconnection between distribution areas, flexible DC interconnection between feeders, and hybrid DC interconnection between distribution areas and feeders. These AC / DC hybrid distribution systems are limited to local AC / DC distribution network construction and have not formed large-scale AC / DC hybrid distribution systems. Therefore, this paper proposes a dandelion-type distribution network based on AC / DC hybrid distribution systems, providing a reference for the construction of large-scale AC / DC hybrid distribution systems and distributed smart microgrids. The dandelion-type distribution network features high power supply reliability, strong resource carrying capacity, flexible self-organizing network, and AC / DC hybrid power supply. To achieve power balance control, collaborative operation, and flexible self-organizing network in the dandelion-type distribution network, communication and control methods for the dandelion-type distribution network are urgently needed. Summary of the Invention

[0004] This invention proposes a communication and control method for dandelion-type distribution networks, which can realize power balance control, collaborative operation, and flexible self-organizing network of dandelion-type topology distribution networks, thereby improving the practicality of this type of distribution network.

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

[0006] A dandelion-type power distribution network communication and control method is disclosed, wherein the power distribution network includes one or more power supply units; each power supply unit includes a low-voltage DC power network and multiple seed power supply units connected to the low-voltage DC power network via a receiving end; each seed power supply unit includes a low-voltage AC / DC converter that converts DC power received at the receiving end into AC power, and the transmitting end of the low-voltage AC / DC converter is connected to the receiving ends of two or more low-voltage distribution areas; the receiving end of the low-voltage DC power network of the power supply unit is connected to the transmitting end of a medium-voltage DC power network via a DC transformer; the receiving end of the medium-voltage DC power network is connected to the transmitting end of one or more medium-voltage AC power networks via a medium-voltage AC / DC converter.

[0007] The power supply units of the dandelion-type distribution network communicate with the outside world using power line carrier, micro-power or multi-mode communication, and its DC side adopts DC droop control to realize self-organizing network between seed power supply units;

[0008] Medium-voltage AC power networks are connected through medium-voltage DC power networks. The medium-voltage AC power networks use DC power line carrier, optical fiber, 4G or 5G communication methods to communicate with the outside world, so as to realize the power balance control, coordinated operation and flexible self-organizing of the distribution network.

[0009] The AC power supply terminal of the low-voltage AC / DC converter is connected to the power receiving terminals of two low-voltage substations; the seed power supply unit includes a DC port, a first AC port, and a second AC port. A coordinated controller controls the power balance of the power supply unit by adjusting the operating mode and power level of the AC / DC converter, thus satisfying...

[0010] P AC_1 (t)+P AC_2 (t)+P DC (t)+P loss (t)=0 Formula 1;

[0011] In the formula, P AC_1 P represents the active power at the first AC port. AC_2 P represents the active power at the second AC port. DC Let t be the active power at the DC port, and t be the time.

[0012] The communication methods between the collaborative controller of the seed power supply unit and the intelligent terminals of the two low-voltage distribution areas include power line carrier PLC, low-power wireless RF, and multi-mode communication. The multi-mode communication includes both power line carrier and low-power wireless communication. The collaborative controller carries the above communication methods through its communication interface.

[0013] The DC side of the seed power supply unit adopts DC droop control, which satisfies...

[0014] U dcref =U0-kI Formula 2;

[0015] In the formula, U dcref U is the DC reference voltage. o I is the DC bus voltage setting value, I is the AC / DC converter output current, and k is the droop curve coefficient.

[0016] The communication between the seed power supply units adopts DC power line carrier, low-power wireless, or multi-mode communication. The multi-mode communication includes both DC power line carrier and low-power wireless communication, and supports network formation without device configuration.

[0017] The low-voltage DC power network is electrically connected to the medium-voltage DC transformer through a DC transformer. The DC transformer communicates with the outside world using DC power line carrier, low-power wireless, multi-mode communication, or fiber optic communication. The multi-mode communication method includes both DC power line carrier and low-power wireless communication, supporting network formation without device configuration.

[0018] The medium-voltage AC power network is electrically connected to the medium-voltage DC power network through a medium-voltage AC / DC converter; the communication methods of the co-controller of the medium-voltage AC / DC converter include DC power line carrier, optical fiber, 4G, and 5G.

[0019] The number of medium-voltage AC power networks is 2 to 4, with one medium-voltage AC-DC converter operating in constant DC voltage control mode and the rest operating in constant power control mode to achieve power balance in the medium-voltage AC-DC power network.

[0020] The seed power supply units communicate with each other to execute DC control based on a consensus algorithm. The droop control expression is as follows:

[0021] U dc_i =U 0_i +ΔU i -k i I i Formula 3, i∈[1,n];

[0022] In the formula, U 0_i The initial DC bus voltage setting value for seed power supply unit i, ΔU i k is the compensation value for the droop curve ordinate of seed power supply unit i. i To determine the droop coefficient Δk after correction based on the seed power supply unit compensator. i The sag coefficient k of the compensator i correction value

[0023] Compensators include voltage compensators and current compensators; a voltage compensator consists of a voltage observer and a proportional-integral regulator, expressed by the formula:

[0024]

[0025] In the formula, U i The sampled voltage value of seed power supply unit i. For the predicted voltage value of the adjacent seed power supply unit j, a ij G is the communication weight between seed power supply units. piv This is the transfer function of the average voltage regulator. The droop coefficient k is also mentioned. i It is obtained by the following calculation method:

[0026]

[0027] In the formula, k 0_i This is the initial droop curve coefficient setting value for seed power supply unit i, Gpic is the transfer function of the average voltage regulator, and ΔI is the initial droop curve coefficient setting value for seed power supply unit i. i This is a mismatched current value;

[0028] Through the adjustment and coordinated action of voltage compensators and current compensators, the DC bus voltage and power inside the dandelion-type distribution network power supply unit are adaptively adjusted, thereby enabling flexible grid connection and disconnection of the seed power supply unit and the self-organizing network of the dandelion-type distribution network.

[0029] The present invention and its preferred embodiments have the following advantages:

[0030] (1) The power supply unit of the dandelion-type distribution network adopts power line carrier or low-power wireless or multi-mode communication to realize reliable communication between adjacent seed power supply units;

[0031] (2) The medium-voltage AC / DC power network of the dandelion-type distribution network adopts power line carrier, optical fiber, 4G or 5G communication to achieve power balance of the medium-voltage AC / DC power network;

[0032] (3) The dandelion-type power supply unit adopts the DC droop control method to realize the adaptive adjustment of DC bus voltage and power inside the power supply unit, thereby realizing the flexible disconnection and connection of the seed power supply unit and the self-organizing network of the dandelion-type power supply network.

[0033] The dandelion-type distribution network communication and control method proposed in this invention can realize power balance control, collaborative operation, and flexible self-organizing network of the dandelion-type topology distribution network, thereby improving the practicality of the dandelion-type distribution network. Attached Figure Description

[0034] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0035] Appendix Figure 1 This is a schematic diagram of the primary and secondary power supply units of the dandelion-type power distribution network of the present invention;

[0036] Appendix Figure 2 This is a schematic diagram of the primary and secondary distribution networks of the dandelion-type power distribution network of the present invention;

[0037] Appendix Figure 3 This is a schematic diagram of the droop control of the dandelion-type DC power distribution network based on the consensus algorithm of the present invention. Detailed Implementation

[0038] In the following, specific embodiments of this application will be described in detail with reference to the accompanying drawings. Based on these detailed descriptions, those skilled in the art will be able to clearly understand and implement this application. Without departing from the principles of this application, features from various embodiments can be combined to obtain new implementations, or certain features from some embodiments can be substituted to obtain other preferred implementations.

[0039] To make the features and advantages of this patent more apparent and understandable, specific embodiments are provided below, along with accompanying drawings, for detailed explanation:

[0040] like Figure 1 As shown, a dandelion-type power distribution network communication and control method is disclosed. The power distribution network includes one or more power supply units. Each power supply unit includes a low-voltage DC power network and multiple seed power supply units connected to the low-voltage DC power network via a receiving end. Each seed power supply unit includes a low-voltage AC / DC converter that converts DC power received at the receiving end into AC power. The transmitting end of the low-voltage AC / DC converter is connected to the receiving end of two or more low-voltage distribution areas. The receiving end of the low-voltage DC power network of the power supply unit is connected to the transmitting end of a medium-voltage DC power network via a DC transformer. The receiving end of the medium-voltage DC power network is connected to the transmitting end of one or more medium-voltage AC power networks via a medium-voltage AC / DC converter.

[0041] The power supply units of the dandelion-type distribution network communicate with the outside world using power line carrier, micro-power or multi-mode communication, and its DC side adopts DC droop control to realize self-organizing network between seed power supply units;

[0042] Medium-voltage AC power networks are connected through medium-voltage DC power networks. The medium-voltage AC power networks use DC power line carrier, optical fiber, 4G or 5G communication methods to communicate with the outside world, so as to realize the power balance control, coordinated operation and flexible self-organizing of the distribution network.

[0043] The AC power supply terminal of the low-voltage AC / DC converter is connected to the power receiving terminals of two low-voltage substations; the seed power supply unit includes a DC port, a first AC port, and a second AC port. A coordinated controller controls the power balance of the power supply unit by adjusting the operating mode and power level of the AC / DC converter, thus satisfying...

[0044] P AC_1 (t)+P AC_2 (t)+P DC (t)+P loss (t)=0 Formula 1;

[0045] In the formula, P AC_1 P represents the active power at the first AC port. AC_2 P represents the active power at the second AC port.DC Let t be the active power at the DC port, and t be the time.

[0046] The communication methods between the collaborative controller of the seed power supply unit and the intelligent terminals of the two low-voltage distribution areas include power line carrier PLC, low-power wireless RF, and multi-mode communication. The multi-mode communication includes both power line carrier and low-power wireless communication. The collaborative controller carries the above communication methods through its communication interface.

[0047] The DC side of the seed power supply unit adopts DC droop control, which satisfies...

[0048] U dcref =U0-kI Formula 2;

[0049] In the formula, U dcref U is the DC reference voltage. o I is the DC bus voltage setting value, I is the AC / DC converter output current, and k is the droop curve coefficient.

[0050] The communication between the seed power supply units adopts DC power line carrier, low-power wireless, or multi-mode communication. The multi-mode communication includes both DC power line carrier and low-power wireless communication, and supports network formation without device configuration.

[0051] The low-voltage DC power network is electrically connected to the medium-voltage DC transformer through a DC transformer. The DC transformer communicates with the outside world using DC power line carrier, low-power wireless, multi-mode communication, or fiber optic communication. The multi-mode communication method includes both DC power line carrier and low-power wireless communication, supporting network formation without device configuration.

[0052] The medium-voltage AC power network is electrically connected to the medium-voltage DC power network through a medium-voltage AC / DC converter; the communication methods of the co-controller of the medium-voltage AC / DC converter include DC power line carrier, optical fiber, 4G, and 5G.

[0053] The number of medium-voltage AC power networks is 2 to 4, with one medium-voltage AC-DC converter operating in constant DC voltage control mode and the rest operating in constant power control mode to achieve power balance in the medium-voltage AC-DC power network.

[0054] The seed power supply units communicate with each other to execute DC control based on a consensus algorithm. The droop control expression is as follows:

[0055] U dc_i =U 0_i +ΔU i -k i I i Formula 3, i∈[1,n];

[0056] In the formula, U 0_i The initial DC bus voltage setting value for seed power supply unit i, ΔU i k is the compensation value for the droop curve ordinate of seed power supply unit i. i To determine the droop coefficient Δk after correction based on the seed power supply unit compensator. i The sag coefficient k of the compensator i correction value

[0057] Compensators include voltage compensators and current compensators; a voltage compensator consists of a voltage observer and a proportional-integral regulator, expressed by the formula:

[0058]

[0059] In the formula, U i The sampled voltage value of seed power supply unit i. For the predicted voltage value of the adjacent seed power supply unit j, a ij G is the communication weight between seed power supply units. piv This is the transfer function of the average voltage regulator. The droop coefficient k is also mentioned. i It is obtained by the following calculation method:

[0060]

[0061] In the formula, k 0_i This is the initial droop curve coefficient setting value for seed power supply unit i, Gpic is the transfer function of the average voltage regulator, and ΔI is the initial droop curve coefficient setting value for seed power supply unit i. i This is a mismatched current value;

[0062] Through the adjustment and coordinated action of voltage compensators and current compensators, the DC bus voltage and power inside the dandelion-type distribution network power supply unit are adaptively adjusted, thereby enabling flexible grid connection and disconnection of the seed power supply unit and the self-organizing network of the dandelion-type distribution network.

[0063] In this example, multiple seed power supply units of the dandelion power distribution network simultaneously obtain power from a low-voltage DC power network, forming a network topology like the pappus of a dandelion seed, while multiple low-voltage DC power networks simultaneously obtain power from a medium-voltage DC power network, forming a network topology like the receptacle of a dandelion flower.

[0064] The above description is a preferred embodiment of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

[0065] This patent is not limited to the above-described preferred embodiments. Anyone can derive other forms of dandelion-type power distribution network communication and control methods based on the inspiration of this patent. All equivalent changes and modifications made within the scope of the patent application of this invention shall fall within the scope of this patent.

Claims

1. A dandelion-type power distribution network communication and control method, characterized in that: The power distribution network includes one or more power supply units; each power supply unit includes a low-voltage DC power network and multiple seed power supply units connected to the low-voltage DC power network via a receiving end; each seed power supply unit includes a low-voltage AC / DC converter that converts DC power received at the receiving end into AC power, and the transmitting end of the low-voltage AC / DC converter is connected to the receiving end of two or more low-voltage distribution areas; the receiving end of the low-voltage DC power network of the power supply unit is connected to the transmitting end of a medium-voltage DC power network via a DC transformer; the receiving end of the medium-voltage DC power network is connected to the transmitting end of one or more medium-voltage AC power networks via a medium-voltage AC / DC converter. The power supply units of the dandelion-type distribution network communicate with the outside world using power line carrier, micro-power or multi-mode communication, and its DC side adopts DC droop control to realize self-organizing network between seed power supply units; Medium-voltage AC power networks are connected through medium-voltage DC power networks. The medium-voltage AC power networks use DC power line carrier, optical fiber, 4G or 5G communication methods to communicate with the outside world, so as to realize the power balance control, coordinated operation and flexible self-organizing of the distribution network. The AC power supply terminal of the low-voltage AC / DC converter is connected to the power receiving terminals of two low-voltage substations; the seed power supply unit includes a DC port, a first AC port, and a second AC port. A coordinated controller controls the power balance of the power supply unit by adjusting the operating mode and power level of the AC / DC converter, thus satisfying... Formula 1; In the formula, P AC_1 P represents the active power at the first AC port. AC_2 P represents the active power at the second AC port. DC Let t be the active power at the DC port, and t be the time. The DC side of the seed power supply unit adopts DC droop control, which satisfies... Formula 2; In the formula, U dcref U is the DC reference voltage. o I is the DC bus voltage setting value, I is the AC / DC converter output current, and k is the droop curve coefficient.

2. The dandelion-type power distribution network communication and control method according to claim 1, characterized in that: The communication methods between the collaborative controller of the seed power supply unit and the intelligent terminals of the two low-voltage distribution areas include power line carrier PLC, low-power wireless RF, and multi-mode communication. The multi-mode communication includes both power line carrier and low-power wireless communication. The collaborative controller carries the above communication methods through its communication interface.

3. The dandelion-type power distribution network communication and control method according to claim 2, characterized in that: The communication between the seed power supply units adopts DC power line carrier, low-power wireless, or multi-mode communication. The multi-mode communication includes both DC power line carrier and low-power wireless communication, and supports network formation without device configuration.

4. The dandelion-type power distribution network communication and control method according to claim 3, characterized in that: The low-voltage DC power network is electrically connected to the medium-voltage DC power network through a DC transformer. The DC transformer communicates externally using DC power line carrier, low-power wireless, multi-mode communication, or fiber optic communication. The multi-mode communication method includes both DC power line carrier and low-power wireless communication, supporting network formation without device configuration.

5. The dandelion-type power distribution network communication and control method according to claim 1, characterized in that: The medium-voltage AC power network is electrically connected to the medium-voltage DC power network through a medium-voltage AC / DC converter; the communication methods of the co-controller of the medium-voltage AC / DC converter include DC power line carrier, optical fiber, 4G, and 5G.

6. The dandelion-type power distribution network communication and control method according to claim 1, characterized in that: The number of medium-voltage AC power networks is 2 to 4, with one medium-voltage AC-DC converter operating in constant DC voltage control mode and the rest operating in constant power control mode to achieve power balance in the medium-voltage AC-DC power network.

7. The dandelion-type power distribution network communication and control method according to claim 2, characterized in that: The seed power supply units communicate with each other to execute DC control based on a consensus algorithm. The droop control expression is as follows: Formula 3; In the formula, U 0_i The initial DC bus voltage setting value for seed power supply unit i, ΔU i k is the compensation value for the droop curve ordinate of seed power supply unit i. i To determine the droop coefficient Δk after correction based on the seed power supply unit compensator. i The sag coefficient k of the compensator i The correction value; Compensators include voltage compensators and current compensators; a voltage compensator consists of a voltage observer and a proportional-integral regulator, expressed by the formula: Formula 4; In the formula, U i The sampled voltage value of seed power supply unit i. For the predicted voltage value of the adjacent seed power supply unit j, a ij G is the communication weight between seed power supply units. piv The transfer function of the average voltage regulator; droop coefficient k i It is obtained by the following calculation method: Formula 5; In the formula, k 0_i This is the initial droop curve coefficient setting value for seed power supply unit i, Gpic is the transfer function of the average voltage regulator, and ΔI is the initial droop curve coefficient setting value for seed power supply unit i. i This is a mismatched current value; Through the adjustment and coordinated action of voltage compensators and current compensators, the DC bus voltage and power inside the dandelion-type distribution network power supply unit are adaptively adjusted, thereby enabling flexible grid connection and disconnection of the seed power supply unit and the self-organizing network of the dandelion-type distribution network.

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