Power system and communication module for solid state transformer structure with communication function

Abstract

Disclosed is a power system and a communication module for a solid-state transformer structure. The power system for the solid-state transformer structure includes a plurality of conversion units, a bus path, a communication module and a control module. The conversion units are coupled to the bus path and the communication module, and the communication module is coupled to the control module. The communication module includes a plurality of coupling units. The coupling units are coupled in series in a manner that one coupling unit is coupled to another coupling unit, and each coupling unit is correspondingly coupled to a control unit of each conversion unit. A starting coupling unit of a series joint end of the coupling units is coupled to the control module.

Description

[0001] This application is a divisional application of the invention patent application filed by Delta Electronics Industrial Co., Ltd., on September 20, 2019, with application number 201910894744.5, entitled "Power System and Communication Module with Solid-State Transformer Structure and Communication Function". Technical Field

[0002] This invention relates to a power system with communication function applied to a solid-state transformer structure (architecture), and particularly to a power system that reduces the difficulty of wiring communication lines. Background Technology

[0003] Traditional power conversion in power grids uses bulky, oil-immersed transformers. In recent years, many organizations have focused on researching and developing solid-state transformers (SSTs). SSTs combine power electronic conversion technology with high-frequency power converter technology based on electromagnetic induction principles, enabling power conversion modules to operate at medium to high frequencies, thus significantly reducing their size. Because SSTs replace traditional transformers in the power grid, their input terminals must withstand high voltages. For example, but not limited to, in a three-phase AC four-wire grid with a Y-connected connection, the line voltage of the three-phase AC is 13.2kV, and the voltage of each phase is 7.62kV. Therefore, the input terminal of each phase of the SST needs to withstand 7.62kV AC voltage, which is then received by multiple power modules connected in series at their input terminals. Each power module has its own control unit, and a system control module communicates with the control units in each power module. Electrical isolation is maintained between the control module and the control units.

[0004] Existing solid-state transformer applications primarily use fiber optic lines to couple system control modules with controllers in various power modules for electrically isolated signal transmission. However, fiber optics have drawbacks such as poor physical strength, susceptibility to breakage, and high installation costs. Integrating fiber optics into the cabinet of a solid-state transformer can lead to difficulties in fiber optic connections and a high risk of breakage, especially given limited cabinet space and a large number of cabling connections.

[0005] Therefore, how to design a power system with communication function that can be applied to solid-state transformer structures, and how to use optocouplers with unique wiring methods to achieve electrical isolation between control modules in solid-state transformers, is an important research topic that the inventors of this disclosure intend to conduct. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a power system with communication functionality applied to a solid-state transformer structure, overcoming the limitations of existing technologies. Therefore, the power system of this invention includes: a conversion module comprising multiple conversion units, each conversion unit including an input terminal, an output terminal, and a control unit, wherein the input terminal of each conversion unit is series-coupled to an AC power supply; a bus path coupled to the output terminal of each conversion unit; a communication module comprising: multiple coupling units, each coupling unit including a signal input terminal and a signal output terminal, the coupling units being series-coupled such that the signal output terminal of one coupling unit is coupled to the signal input terminal of another coupling unit, and the signal output terminal of each coupling unit being correspondingly coupled to the control unit of each conversion unit; and a control module coupled to the signal input terminal of the initial coupling unit at the series-coupled terminal of the coupling units.

[0007] To address the aforementioned problems, this invention provides a communication module applied to a solid-state transformer structure, overcoming the limitations of existing technologies. Therefore, the communication module of this invention couples multiple conversion units and a control module within a conversion module, with each conversion unit including a control unit. The communication module includes multiple coupling units, each including a signal input terminal and a signal output terminal. The coupling units are connected in series such that the signal output terminal of one coupling unit is coupled to the signal input terminal of another coupling unit, and the signal output terminal of each coupling unit is correspondingly coupled to the control unit of each conversion unit. Specifically, the signal input terminal of the initial coupling unit at the series connection end is coupled to the control module.

[0008] To gain a deeper understanding of the techniques, means, and effects employed by this invention to achieve its intended purpose, please refer to the following detailed description and accompanying drawings. It is believed that the purpose, features, and characteristics of this invention can be understood in a thorough and specific manner from these drawings. However, the accompanying drawings are provided for reference and illustration only and are not intended to limit the scope of this invention. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of the circuit block of the three-phase power system of the present invention;

[0010] Figure 2 This is a circuit block diagram of the present invention applied to a power system with a solid-state transformer structure and communication function.

[0011] Figure 3 This is a circuit block diagram of the first embodiment of the communication module coupling conversion module of the present invention; and

[0012] Figure 4 This is a circuit block diagram of a second embodiment of the communication module coupling conversion module of the present invention.

[0013] Explanation of reference numerals in the attached figures:

[0014] 1…Three-phase power system

[0015] R, S, T... Fireline

[0016] N…neutral point

[0017] 100, 100A, 100B, 100C… power systems

[0018] 10…Conversion Module

[0019] 12-1~12-n… conversion unit

[0020] 122… Input terminal

[0021] 124… Output terminal

[0022] 126…Control Unit

[0023] 20…bus path

[0024] 30…Conversion Circuit

[0025] 40…Control Module

[0026] 50… communication module

[0027] 52-1~52-n…Coupled Units

[0028] 522… signal input terminal

[0029] 524… signal output terminal

[0030] 200…load

[0031] Vin…Three-phase AC power supply

[0032] Vac, Vac1, Vac2, Vac3… AC power supply

[0033] Vl…load power supply

[0034] Vbus…bus power supply

[0035] Sc, Sc1~Scn… control signals Detailed Implementation

[0036] The technical content and detailed description of the present invention are explained below with reference to the accompanying drawings:

[0037] Please see Figure 1This is a schematic diagram of the circuit block of the three-phase power system of the present invention. The three-phase power system 1 includes three sets of power systems (100A, 100B, 100C) with communication functions applied to a solid-state transformer structure. Each set of power systems (100A, 100B, 100C) is coupled to one phase of the three-phase AC power supply Vin (Vac1, Vac2, Vac3) to convert the AC power supply (Vac1, Vac2, Vac3) into load power supply V1 to supply power to multiple loads 200. The three-phase AC power supply Vin is a medium- or high-voltage power system. For example, in the embodiment of this specification, its line voltage is an AC voltage of 13.2kV, i.e., the voltage of each phase is 7.62kV. It is worth mentioning that in this invention, the AC power supply Vin is not limited to single-phase or three-phase, nor is it limited to a Y-connected or Δ-connected structure; and the load 200 can be one or more loads 200 connected to each group of power systems, or all power systems can be coupled to a common load 200, depending on the combination of power supply and load demand of the power system. Figure 1 This is merely a schematic example of a three-phase AC power supply with Vin connected in a Y configuration.

[0038] Please see Figure 2 This is a circuit block diagram of the present invention applied to a power system with a solid-state transformer structure and communication function, in conjunction with the following references. Figure 1 The power system 100 includes a conversion module 10, a bus path 20, a conversion circuit 30, and a control module 40. The bus path 20 is coupled to the conversion module 10 and the conversion circuit 30, and the control module 40 is coupled to the conversion module 10. The conversion module 10 receives AC power Vac, and the control module 40 controls the conversion module 10 to convert the AC power Vac to bus power Vbus or controls the power distribution of its conversion module 10. The conversion circuit 30 receives the bus power Vbus through the bus path 20 and converts the bus power Vbus to load power Vl to supply power to the load 200. It is worth noting that in one embodiment of the present invention, the power system (100A, 100B, 100C) can also be fed back to the AC power Vac from the load 200, with the path being exactly the opposite of charging; this will not be elaborated further here.

[0039] Specifically, the conversion module 10 includes multiple conversion units 12-1 to 12-n, and each conversion unit 12-1 to 12-n includes an input terminal 122, an output terminal 124, and a control unit 126. The input terminals 122 of each conversion unit 12-1 to 12-n are connected in series, with the starting conversion unit 12-1 at the end of the series connection coupled to the live wire (R, S, T, with R phase as an illustrative example), and the ending conversion unit 12-n at the end of the series connection coupled to the neutral point N. Due to this connection structure, the conversion units 12-1 to 12-n ideally distribute the AC power Vac evenly. The output terminal 124 of each conversion unit 12-1 to 12-n is coupled to the bus path 20, and the bus path 20 in the power system (100A, 100B, 100C) (e.g., ...) Figure 2 (As shown) can be coupled to the same point or be independent paths.

[0040] The conversion module 10 can be a solid-state transformer (SST), a new type of smart transformer suitable for smart grid applications. It primarily replaces the bulky, oil-immersed traditional transformers used in high-voltage systems. Specifically, traditional transformers typically require thick wires to withstand low-frequency high-voltage currents. Therefore, traditional transformers are bulky and unsuitable for space-constrained environments. Since the conversion module 10 of this invention has multiple conversion units 12-1 to 12-n connected in series at the input terminals, and these units operate in a high-frequency switching environment, their size is smaller. Therefore, the solid-state transformer is smaller than the transformers used in traditional high-voltage systems. It can not only achieve voltage conversion (conversion between high and low voltage), electrical isolation, and fault isolation, but also frequency conversion (conversion between DC and AC) that traditional transformers cannot achieve. Furthermore, solid-state transformers possess both AC and DC links, enabling conversion between DC low-voltage, DC high-voltage, AC low-voltage, and AC high-voltage states. Therefore, in applications where the AC power supply Vac is medium to high voltage (e.g., but not limited to, 4.8kV to 35kV), solid-state transformers are particularly suitable for bidirectional conversion between high and low voltage. This overcomes the limitation of traditional transformers, which are only suitable for single-frequency, unidirectional voltage transmission and cannot perform bidirectional voltage conversion.

[0041] The control module 40 is coupled to the control unit 126 in each conversion unit 12-1 to 12-n and communicates with the control unit 126 via the control signal Sc. The control unit 126 controls the conversion units 12-1 to 12-n to convert AC power Vac to bus power Vbus, and stabilizes the voltage value of the bus power Vbus provided by the conversion units 12-1 to 12-n (or controls each conversion unit 12-1 to 12-n to convert the bus power Vbus to AC power Vac, and feeds the AC power Vac back to the power grid). The control module 40 learns the current status of the control unit 126 through the control signal Sc, and controls the control unit 126 to adjust the output current of the conversion units 12-1 to 12-n, so that the output current of each conversion unit 12-1 to 12-n is shared or adjusted as needed. The conversion circuit 30 may include one or more converters (not shown), and the converters may be DC / DC converters or DC / AC converters (depending on the needs of the load 200). The conversion circuit 30 couples the bus path 20 to the load 200, and the number of loads 200 it can couple to is determined by the number of converters. The conversion circuit 30 can convert the bus power supply Vbus to the load power supply Vl according to the power configuration of the power system (100A, 100B, 100C), and provide the load power supply Vl to the load 200 (or convert the load power supply Vl to the bus power supply Vbus, and provide the bus power supply Vbus to the conversion module 10). It is worth noting that in one embodiment of the present invention, the conversion circuit 30 can be omitted according to actual needs. That is, when the bus power supply Vbus provided by the bus path 20 can be used as the power for the load operation, the conversion circuit 30 can be omitted, allowing the load 200 to be directly coupled to the bus path 20.

[0042] The existing communication between the control unit 126 and the control module 40 in each conversion unit 12-1 to 12-n is a one-to-one connection, meaning each control unit 126 has a signal line connected to the control module 40. Since the voltage received by the power system (100A, 100B, 100C) is in the range of several kV to tens of kV, but the control module 40 is a control device that personnel may come into contact with, it needs to operate in a Safety Extra-Low Voltage (SELV) environment. Specifically, a safety voltage operating environment is an extra-low voltage operating environment that is electrically isolated from ground and other systems. This electrical isolation prevents the risk of electric shock to personnel in the event of a single fault. Safety voltage is typically set in an operating environment, for example, but not limited to, below 50V. To achieve electrical isolation, the existing practice uses fiber optic lines for signal transmission. However, since the communication module 40 and control unit 126 are connected one-to-one, assuming there are 10 conversion units, 10 fiber optic lines would be required. To simplify wiring and improve space utilization, a communication module 50 is used in this invention to provide electrical isolation between medium- and high-voltage operating environments and safe-voltage operating environments. The communication module 50 is coupled to the control module 40 and the control unit 126 in each conversion unit 12-1 to 12-n.

[0043] When the control module 40 wants to control the control unit 126, the control module 40 provides a control signal Sc to the communication module 50, and the control unit 126 obtains its own control signals Sc1 to Scn from the communication module 50. When the control unit 126 wants to send information back to the control module 40, the control unit 126 provides its own control signals Sc1 to Scn to the communication module 50. The communication module 50 integrates the control signals Sc1 to Scn into a control signal Sc and provides the control signal Sc to the control module 40. It is worth mentioning that in one embodiment of the present invention, each power system (100A, 100B, 100C) includes a control module 40, but this is not a limitation. In other words, the three power systems (100A, 100B, 100C) can also be integrated into a single control module 40, so that a single control module 40 can jointly control the three power systems (100A, 100B, 100C).

[0044] Please see Figure 3 This is a circuit block diagram of the first embodiment of the communication module coupling conversion module of the present invention, in conjunction with reference to... Figures 1-2The communication module 50 includes multiple coupling units 52-1 to 52-n, and each coupling unit 52-1 to 52-n includes a signal input terminal 522 and a signal output terminal 524. The coupling units 52-1 to 52-n are connected in series such that the signal output terminal 524 of one coupling unit 52-1 to 52-n is coupled to the signal input terminal 522 of another coupling unit 52-1 to 52-n (i.e., the coupling units 52-1 to 52-n are coupled in series), and the signal output terminal 524 of each coupling unit 52-1 to 52-n is correspondingly coupled to the control unit 126 of each conversion unit 12-1 to 12-n. Among the coupling units 52-1 to 52-n, the signal input terminal 522 of the initial coupling unit 52-1 at the series connector end is coupled to the control module 40.

[0045] Since the control module 40 needs to supply multiple control units 126 when transmitting a single control signal Sc, it needs to transmit control signals Sc including multiple packets to the initial coupling unit 52-1 within a unit time. The control unit 126 in the initial conversion unit 12-1 obtains its own control signal Sc1 from the initial coupling unit 52-1, and the initial coupling unit 52-1 provides control signals Sc including the remaining packets to the coupling unit 52-2, and so on. Since the number of packets in the control signal Sc is equal to the number of conversion units 12-1 to 12-n, each control unit 126 in each conversion unit 12-1 to 12-n has corresponding receivable packets. It is worth noting that when the control unit 126 returns control signals Sc1 to Scn, the transmission method is the same, but the path is exactly reversed; this will not be elaborated further here.

[0046] Furthermore, the coupling units 52-1 to 52-n are optical couplers. The characteristic of an optical coupler is that, through the optical coupling transmission characteristic, the signals at both ends of the optical coupler are electrically isolated. Since power systems (100A, 100B, 100C) are typically housed in cabinets with limited space, using fiber optic lines with the same electrical isolation function is difficult due to limited cabinet space and complex wiring, and the fiber optic lines are prone to breakage due to excessive bending. Because the wiring configuration of the communication module 50 of this invention uses the series coupling characteristic of coupling units 52-1 to 52-n, the number of lines coupled to the control module 40 and the control unit 126 is reduced, thus lowering the complexity of configuring the communication module 50 in the cabinet. That is, although the communication line from the control module 40 to the coupling unit 52-1 still uses a fiber optic line, the communication line from the coupling units 52-1 to 52-n to the conversion module 10 does not need to use a fiber optic line; ordinary wires can be used instead. Since optical couplers have a lower configuration cost than fiber optic lines, they can reduce the complexity and space required to configure the communication module 50 in the cabinet, as well as reduce configuration costs.

[0047] Please see Figure 4 This is a circuit block diagram of the second embodiment of the communication module coupling conversion module of the present invention, in conjunction with the following references. Figures 1-2 This embodiment is similar to... Figure 3 The difference in the first embodiment is that the control unit 126 of the end conversion unit 12-n is coupled to the signal output terminal 524 of the start coupling unit 52-1. Specifically, when one of the input terminals 122 of the end conversion unit 12-n is coupled to the neutral point N, the voltage difference between the live wire R and the neutral point N is as high as 7.62kV. However, since the line configuration of the communication module 50 of the present invention uses the characteristic of series coupling of coupling units 52-1 to 52-n, the total withstand voltage value can be evenly distributed like that of the conversion units 12-1 to 12-n. The total withstand voltage value corresponds to the voltage value of the AC power supply Vac, that is, if the voltage difference between the live wire R and the neutral point N is as high as 7.62kV, the total withstand voltage value must be designed to be greater than or equal to 7.62kV. Assuming there are 10 sets of conversion units 12-1 to 12-n, corresponding to 10 sets of coupling units 52-1 to 52-n, the withstand voltage value of each coupling unit 52-1 to 52-n must be designed to be greater than or equal to 762V. Since the higher the withstand voltage of coupling units 52-1 to 52-n, the higher their circuit cost, when the withstand voltage of coupling units 52-1 to 52-n is selected using an average distribution method, it is not necessary for each coupling unit 52-1 to 52-n to be designed to have a withstand voltage greater than or equal to the total withstand voltage. Therefore, the technical effect of significantly reducing the construction cost of communication module 50 can be achieved.

[0048] In summary, the embodiments of the present invention have the following advantages and technical effects:

[0049] 1. The main technical effect of the present invention is that by using the special wiring method of series coupling of the coupling unit in the communication module, the communication between the control module and the power system can greatly reduce the use of optical fiber lines, thereby reducing the complexity of the communication module in the cabinet and reducing the configuration cost.

[0050] 2. The control module, which operates in a safe voltage environment, is electrically isolated from the power system, which operates in a high voltage environment, by using the coupling unit in the communication module to avoid the risk of personnel coming into contact with high voltage electricity;

[0051] 3. Since the withstand voltage values ​​of the coupling units in the communication module can be selected in an evenly distributed manner, this method can significantly reduce the construction cost of the communication module.

[0052] 4. Because the conversion module uses a solid-state transformer, the conversion unit is particularly suitable for bidirectional conversion between high voltage and low voltage. This overcomes the shortcomings of traditional transformers, which are only suitable for single-frequency, unidirectional voltage transmission and cannot be used with switching converters to convert voltage bidirectionally.

[0053] The above description is merely a detailed explanation and accompanying drawings of preferred embodiments of the present invention, and the features of the present invention are not limited thereto, nor are they intended to limit the present invention. The full scope of the present invention should be determined by the following claims. All embodiments that conform to the spirit of the claims of the present invention and similar variations thereof should be included within the scope of the present invention. Any variations or modifications that can be easily conceived by those skilled in the art within the field of the present invention are covered by the claims disclosed herein. Furthermore, the features mentioned in the claims and description can be implemented individually or in any combination.

Claims

1. A power system with communication function applied to a solid-state transformer structure, comprising: A conversion module includes multiple conversion units. Each conversion unit includes an input terminal, an output terminal, and a control unit. The input terminal of each conversion unit is connected in series with an AC power supply, wherein one end of the AC power supply is a neutral point. Among these conversion units, a starting conversion unit at the series terminal is coupled to the live wire of the AC power supply, and a ending conversion unit at the series terminal is coupled to the neutral point. A single bus path is used to couple to the output of each conversion unit; and A communication module, including: Multiple coupling units, each including a signal input terminal and a signal output terminal, are connected in series such that the signal output terminal of one coupling unit is coupled to the signal input terminal of another coupling unit, and the signal output terminal of each coupling unit is correspondingly coupled to the control unit of each conversion unit; and A control module is coupled to the signal input terminal of an initial coupling unit at the serial connector of the coupling units. The control module transmits multiple packets to the initial coupling unit per unit time, and the number of packets is equal to the number of conversion units. Each conversion unit's control unit receives one of the packets. The control unit coupled to the initial coupling unit receives its own control signal, and the initial coupling unit provides control signals including the remaining packets to the next coupling unit, and so on.

2. The power system of claim 1, wherein in the conversion units, the control unit of a starting conversion unit at the series connector terminal is coupled to the signal output terminal of the starting coupling unit, or the control unit of the ending conversion unit is coupled to the signal output terminal of the starting coupling unit.

3. The power system of claim 1, wherein the coupling units are evenly distributed with a total withstand voltage value corresponding to the voltage value of the AC power supply.

4. The power system of claim 1, wherein the coupling units are an optocoupler that electrically isolates the control module operating in a safe voltage environment from the control unit operating in a high voltage environment.

5. The power system of claim 1, wherein the control unit in each conversion unit controls each conversion unit to convert the AC power supply into a bus power supply and provides the bus power supply to the bus path.

6. A communication module applied to a solid-state transformer structure, coupled to a plurality of conversion units in a conversion module and a control module, wherein each conversion unit includes a control unit, wherein the input terminal of each conversion unit is connected in series and coupled to an AC power supply, one end of the AC power supply being a neutral point, and among the conversion units, a starting conversion unit at the series end is coupled to the live wire of the AC power supply, and a ending conversion unit at the series end is coupled to the neutral point, the communication module comprising: Multiple coupling units, each including a signal input terminal and a signal output terminal, are connected in series such that the signal output terminal of one coupling unit is coupled to the signal input terminal of another coupling unit, and the signal output terminal of each coupling unit is correspondingly coupled to the control unit of each conversion unit. Among these coupling units, the signal input terminal of an initial coupling unit at the serial connector end is coupled to the control module. The control module transmits multiple packets to the initial coupling unit per unit time, and the number of these packets is equal to the number of these conversion units. This allows the control unit of each conversion unit to receive one of these packets. The control unit coupled to the initial coupling unit will obtain its own control signal, and the initial coupling unit will provide the control signal, including the remaining packets, to the next coupling unit, and so on.

7. The communication module of claim 6, wherein in the conversion units, the control unit of a starting conversion unit at the serial connector terminal is coupled to the signal output terminal of the starting coupling unit, or the control unit of the ending conversion unit is coupled to the signal output terminal of the starting coupling unit.

8. The communication module of claim 6, wherein the coupling units are evenly distributed with a total withstand voltage value corresponding to the voltage value of the AC power supply.

9. The communication module of claim 6, wherein the coupling units are an optical coupler that electrically isolates the control module operating in a safe voltage environment from the control unit operating in a high voltage environment.

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