Three-port energy router topological structure and control method thereof
By introducing a series isolation transformer and a type-I three-level topology into the three-port energy router, the problems of high efficiency loss and low reliability of the three-port energy router are solved, and efficient and reliable energy conversion and load-balanced power supply are achieved.
Patent Information
- Application Number
- CN202610150572.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-02-03
- Publication Date
- 2026-04-28
AI Technical Summary
Existing three-port energy routers suffer from high efficiency loss and low reliability when converting energy between two distribution areas.
A three-port energy router topology is adopted, including a first AC port, a second AC port and a DC port, three power modules and an electrical isolation unit. Power regulation and electrical isolation are achieved by using a series isolation transformer and a type I three-level topology. The third power module outputs a compensation voltage to balance the load in the distribution area and is powered by an energy storage device.
It improves energy conversion efficiency and reliability, achieves load balancing and power supply reliability during power outages, and reduces overall power supply costs.
Smart Images
Figure CN121939428A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of power electronic conversion technology, specifically to a three-port energy router topology and its control method. Background Technology
[0002] Currently, there are two main solutions for three-port energy routers. One solution has no interconnection device on the AC side, and the two transformer substations are interconnected on the DC side via bidirectional AC / DC modules. While this solution can achieve energy interconnection between the two substations, it relies entirely on AC / DC module conversion, resulting in significant efficiency losses. The other solution also includes interconnection on the AC side, enabling energy conversion between the two substations. This solution uses a structure of two bidirectional AC / DC modules, with the left side in parallel and the right side in series, but its efficiency still needs further improvement. Summary of the Invention
[0003] To address the aforementioned technical shortcomings, the present invention aims to provide a three-port energy router topology, thereby resolving the issues of high efficiency loss and low reliability in current three-port energy routers when converting energy between two distribution areas.
[0004] To solve the above technical problems, the present invention adopts the following technical solution: The present invention provides a three-port energy router topology, comprising: The system consists of three ports: a first AC port, a second AC port, and a DC port; three power modules: a first power module, a second power module, and a third power module; and an electrical isolation unit. The AC side of the first power module is connected to the first AC port, and the DC side is connected to the DC port. The AC side of the second power module is connected to the second AC port, and the DC side is connected to the DC port; The DC side of the third power module is connected to the DC port; The electrical isolation unit is connected between the first AC port, the second AC port and the AC side of the third power module, and is used to achieve power regulation between the first AC port and the second AC port.
[0005] Furthermore, the electrical isolation unit includes a series isolation transformer, the primary side of which is connected between the first AC port and the second AC port, and the secondary side of which is connected to the AC side of the third power module.
[0006] Furthermore, all three power modules are bidirectional AC / DC converters.
[0007] Furthermore, the bidirectional AC / DC converter adopts a type I three-level topology.
[0008] Furthermore, the DC port can also be connected to one or more devices, including photovoltaic, energy storage, and charging piles.
[0009] A control method for a three-port energy router topology includes: When the load rates of the stations connected to the first AC port and the second AC port are unbalanced and power mutual assistance is required, the magnitude and phase of the compensation voltage ΔU that the third power module should output are calculated based on the power value to be transmitted. The third power module is controlled to output the compensation voltage ΔU, which is coupled between the two substations via an electrical isolation unit, driving power to flow from the substation with low load rate to the substation with high load rate.
[0010] Furthermore, it also includes: when the transformer substations connected to the first AC port and the second AC port lose power, the energy storage device connected to the DC port converts the DC power into AC power through the first power module and the second power module to supply power to the loads of the two transformer substations.
[0011] Furthermore, it also includes: during off-peak hours, while the power grid supplies power to the load, the transformer areas connected to the first AC port and the second AC port charge the energy storage battery through the first power module and the second power module.
[0012] The beneficial effects of this invention are as follows: 1. This invention adopts a "parallel-series-parallel" topology, which has higher efficiency compared to the ordinary "parallel-series" structure. When converting DC to AC to supply power to two transformer substations, the "parallel-series-parallel" topology directly supplies power to the corresponding two substations through two parallel power conversion modules, resulting in higher efficiency. In contrast, the "parallel-series" structure requires power to pass through the primary circuit of a series transformer, leading to lower efficiency.
[0013] 2. The "parallel-series-parallel" topology structure adopted in this invention has higher reliability in use. If one of the two parallel power conversion modules fails, it will not affect the overall function. This solution is more suitable for places with high power supply reliability requirements. Attached Figure Description
[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0015] Figure 1 This is a schematic diagram of the three-port energy router topology provided in Embodiment 1 of the present invention; Figure 2This is a schematic diagram of the topology of the three power modules provided in Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the power grid charging the battery and supplying power to the charging terminal provided in Embodiment 2 of the present invention; Figure 4 This is a schematic diagram of photovoltaic or energy storage batteries providing power to a distribution area, as provided in Embodiment 2 of the present invention. Figure 5 This is a schematic diagram of the power supply mode for the charging terminal during peak electricity consumption provided in Embodiment 2 of the present invention. Detailed Implementation
[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example
[0017] This embodiment provides a three-port energy router topology, such as... Figure 1 As shown, it includes: three ports: a first AC port, a second AC port, and a DC port; three power modules: a first power module, a second power module, and a third power module; and an electrical isolation unit. Specifically, the first AC port, the second AC port, and the DC port are the incoming line ports of transformer substation #1, transformer substation #2, and the 750V DC bus, respectively, as shown in the figure; the electrical isolation unit is the series isolation transformer shown in the figure.
[0018] Preferably, the incoming port of transformer substation #1 is connected to the AC side of the first power module and the series isolation transformer, respectively; the incoming port of transformer substation #2 is connected to the AC side of the second power module and the series isolation transformer, respectively; the secondary side of the series isolation transformer is connected to the AC side of the third power module; the DC sides of the third power module, the first power module, and the second power module are all connected to the 750V DC bus; the DC bus is also connected to photovoltaic, energy storage, and charging piles; the AC side of the first power module is connected to the incoming port of transformer substation #1, converting AC power into DC power and sending it to the 750V DC bus, and can also convert power on the 750V DC bus into AC power and send it to the AC side of the first power module; the AC side of the second power module is connected to the incoming port of transformer substation #2, converting AC power into DC power and sending it to the 750V DC bus. It can convert DC power to AC power and send it to the 750V DC bus; similarly, it can convert the power on the 750V DC bus to AC power and send it to the AC side of the second power module; the AC side of the first power module and the AC side of the second power module are connected to the primary side of a series isolation transformer, which connects the AC sides of the two modules together, thus physically realizing the interconnection path between the 1# and 2# transformer areas; the primary side of the series transformer is connected between the AC sides of the first power module and the second power module, and the secondary side is connected to the AC side of the third power module; the DC side of the third power module is connected to the 750V DC bus, and can take energy from the DC side and output the corresponding voltage on the AC side to adjust the power flow and magnitude of the system when needed.
[0019] Preferably, one end of the 750V DC bus is connected to the DC side of the first power module, the DC side of the second power module, the DC side of the third power module, and external photovoltaic, energy storage, and charging piles. In actual use, the first and second power modules can provide energy to the energy storage battery and charging piles. At the same time, the electrical energy in the photovoltaic or energy storage can be discharged to the grid for use by the load through the first and second power modules.
[0020] like Figure 2 As shown, all three power modules use a type-I three-level topology. , The capacitor is located on the DC bus side. Each bridge arm consists of four power switching transistors Tx1 to Tx4 and two clamping diodes Dx1 and Dx2. , , These are the phase voltages of the three-phase power grid, A, B, and C. , , These are the three-phase output currents of phases A, B, and C on the inverter side, respectively. The DC side midpoint current; the Type I three-level topology, with its unique stepped wave synthesis mechanism and midpoint potential balance control advantage, has shown significant technical advantages in key indicators such as device voltage stress distribution, output waveform quality and system conversion efficiency, and has become a new mainstream technical solution. This topology effectively reduces the voltage stress and switching loss of power devices while keeping the switching frequency constant through a three-level space vector modulation strategy, and significantly improves the output waveform quality. It provides key technical support for the design of power modules of intelligent on-load tap-changing distribution transformers. In terms of electrical topology, it has multiple working modes and can perform continuous smooth voltage regulation and address various quality issues of voltage and current. Example
[0021] Based on Embodiment 1, this embodiment provides a control method for a three-port energy router topology, such as... Figure 3 As shown, this is an energy sharing mode between two transformer substations. When the load rate of transformer #2 is relatively high, reaching 80%, while the load rate of transformer #1 is 30%, the load distribution between the two substations is unbalanced. In this situation, a three-port energy router is used to adjust the load distribution, transferring power from the low-load substation #1 to substation #2 for its load use.
[0022] For example, when it is necessary to transfer a certain amount of power to transformer substation #2, this embodiment controls two third power modules. The output voltage is fed back to the primary side of the series isolation transformer to generate a voltage ΔU, which overcomes the voltage drop of the line between the two transformer substations. This allows the power to be delivered from transformer substation #1 to transformer substation #2 according to the set power, reducing the load rate of the transformer in transformer substation #2 and enabling the load between the transformer substations to be evenly distributed.
[0023] like Figure 4 As shown, photovoltaic or energy storage supplies power to the loads of transformer substations #1 and #2. When transformer substations #1 and #2 experience a power outage, the photovoltaic or energy storage interface can supply power to the loads of the two substations through the first power module and the second power module.
[0024] like Figure 5 As shown, during off-peak hours, while the grid supplies power to the load, the two transformer substations charge the energy storage battery through the first and second power modules. If the photovoltaic system has excess power, it will also charge the energy storage battery, thus achieving peak shaving and valley filling.
[0025] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A three-port energy router topology, characterized in that, include: The system consists of three ports: a first AC port, a second AC port, and a DC port; three power modules: a first power module, a second power module, and a third power module; and an electrical isolation unit. The AC side of the first power module is connected to the first AC port, and the DC side is connected to the DC port. The AC side of the second power module is connected to the second AC port, and the DC side is connected to the DC port; The DC side of the third power module is connected to the DC port; The electrical isolation unit is connected between the first AC port, the second AC port and the AC side of the third power module, and is used to achieve power regulation between the first AC port and the second AC port.
2. The three-port energy router topology as described in claim 1, characterized in that, The electrical isolation unit includes a series isolation transformer, the primary side of which is connected between the first AC port and the second AC port, and the secondary side of which is connected to the AC side of the third power module.
3. The three-port energy router topology as described in claim 1, characterized in that, All three power modules are bidirectional AC / DC converters.
4. The three-port energy router topology as described in claim 3, characterized in that, The bidirectional AC / DC converter adopts a type I three-level topology.
5. The three-port energy router topology as described in claim 1, characterized in that, The DC port can also be connected to one or more devices, including photovoltaic, energy storage, and charging piles.
6. A control method based on the three-port energy router topology as described in any one of claims 1 to 5, characterized in that, When the load rates of the stations connected to the first AC port and the second AC port are unbalanced and power mutual assistance is required, the magnitude and phase of the compensation voltage ΔU that the third power module should output are calculated based on the power value to be transmitted. The third power module is controlled to output the compensation voltage ΔU, which is coupled between the two substations via an electrical isolation unit, driving power to flow from the substation with low load rate to the substation with high load rate.
7. The control method for the three-port energy router topology as described in claim 6, characterized in that, Also includes: When the transformer substations connected to the first AC port and the second AC port lose power, the energy storage device connected to the DC port converts the DC power into AC power through the first power module and the second power module to supply power to the loads of the two transformer substations.
8. The control method for the three-port energy router topology as described in claim 6, characterized in that, Also includes: During off-peak hours, while the power grid supplies power to the load, the transformer stations connected to the first and second AC ports charge the energy storage batteries through the first and second power modules.