Power quality control system
By integrating a switch module to short-circuit the power inverter during shutdown and using a transformer module for three-phase voltage balancing, the system addresses the issue of converter damage from high grid voltage, improving stability and reliability.
Patent Information
- Application Number
- CN202422264863.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-14
- Publication Date
- 2025-07-15
- Estimated Expiration
- 2034-09-14
AI Technical Summary
In UPQC systems, when the series voltage compensator is in a shutdown state or not working state, the grid high voltage will directly damage the power converter, resulting in damage to the power converter module in the power quality management system.
By introducing transformer modules, power conversion modules and switch modules into the power quality control system, the AC port of the off-grid inverter is connected to the transformer modules and switch modules to form a bypass circuit. When the off-grid inverter is in a shutdown state, the switch module is controlled to be turned on and off, so that it is short-circuited to prevent the power grid from entering the off-grid inverter, thereby protecting the power conversion module.
It improves the stability and reliability of the power quality control system, prevents damage to the power converter by the high voltage of the power grid, and ensures the safe operation of the system.
Smart Images
Figure CN223109667U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of power electronics technology, and more particularly, to a power quality control system. Background Art
[0002] In the field of power quality management, common power quality management devices include shunt compensators or filters, series compensators or filters, etc. Among them, shunt compensators mainly compensate for harmonic and reactive currents on the load side, and can also manage three-phase active power imbalance in specific scenarios to achieve three-phase energy transfer and ensure approximate balance of three-phase loads; series compensators mainly compensate for voltage, including fundamental voltage and harmonic voltage. However, both of the above two compensators or filters have their own advantages and disadvantages. Therefore, the combined use of the two compensators has become a unified power quality controller (UPQC), such as the currently common series-parallel active power compensator or filter. This unified power quality controller can compensate both current and voltage, with rich functions.
[0003] In related technologies, the UPQC system structure usually consists of two back-to-back power converters. One end of the power converter is connected to the power grid, and the other end is connected in series to the power grid through a transformer, forming a DC bus inside the UPQC system. Among them, the power converter directly connected to the power grid constitutes a shunt current compensator, and the power converter connected in series to the power grid through a transformer constitutes a series voltage compensator. The DC bus in the UPQC system is controlled by the shunt current compensator, which can not only achieve current compensation but also maintain the stability of the DC bus through active current.
[0004] However, when performing power quality management based on related technologies, when the series voltage compensator is in a shutdown state or not working, the high voltage of the power grid will directly damage the power converter, causing damage to the power converter module in the power quality management system. Summary of the Utility Model
[0005] The purpose of this application is to provide a power quality control system, which can achieve the effect of improving the stability and reliability of the power quality control system.
[0006] The embodiments of this application are implemented as follows:
[0007] In the first aspect of the embodiments of this application, a power quality control system is provided. The power quality control system includes: a transformer module, a power conversion module, and a switch module. The power conversion module includes: an off-grid inverter;
[0008] One end of the transformer module is used to connect to a three-phase power grid, and the other end of the transformer module is connected to the AC port and the neutral line of the off-grid inverter in the power conversion module;
[0009] The AC port of the off-grid inverter is also connected to the input end of the switch module, the output end of the switch module is connected to the neutral line of the off-grid inverter, and the control end of the switch module is respectively connected to the signal control end of the off-grid inverter and an external drive circuit.
[0010] As a possible implementation, the switch module includes: a first switch unit, a second switch unit, and a third switch unit, and the AC port of the off-grid inverter includes: a first AC terminal, a second AC terminal, and a third AC terminal;
[0011] The input end of the first switch unit is connected to the first AC terminal of the off-grid inverter, the input end of the second switch unit is connected to the second AC terminal of the off-grid inverter, and the input end of the third switch unit is connected to the third AC terminal of the off-grid inverter;
[0012] The output ends of the first switch unit, the second switch unit, and the third switch unit are all connected to the neutral line of the off-grid inverter, and the control ends of the first switch unit, the second switch unit, and the third switch unit are all connected to the signal control end of the off-grid inverter and an external drive circuit.
[0013] As a possible implementation, the first switch unit includes: a first electronic switch and a first mechanical switch;
[0014] The input end of the first electronic switch and the input end of the first mechanical switch are both connected to the first AC terminal of the off-grid inverter, and the output end of the first electronic switch and the output end of the first mechanical switch are both connected to the neutral line of the off-grid inverter;
[0015] The control end of the first electronic switch is connected to the signal control end of the off-grid inverter, and the control end of the first mechanical switch is used to connect to an external drive circuit.
[0016] As a possible implementation, the second switch unit includes: a second electronic switch and a second mechanical switch;
[0017] The input end of the second electronic switch and the input end of the second mechanical switch are both connected to the second AC terminal of the off-grid inverter, and the output end of the second electronic switch and the output end of the second mechanical switch are both connected to the neutral line of the off-grid inverter;
[0018] The control end of the second electronic switch is connected to the signal control end of the off-grid inverter, and the control end of the second mechanical switch is used to connect to an external drive circuit.
[0019] As a possible implementation manner, the third switch unit includes: a third electronic switch and a third mechanical switch;
[0020] The input end of the third electronic switch and the input end of the third mechanical switch are both connected to the third AC terminal of the off-grid inverter, and the output end of the third electronic switch and the output end of the third mechanical switch are both connected to the neutral line of the off-grid inverter;
[0021] The control end of the third electronic switch is connected to the signal control end of the off-grid inverter, and the control end of the third mechanical switch is used to access an external drive circuit.
[0022] As a possible implementation manner, the transformer module includes: at least one transformer;
[0023] The first ends of the transformers are used to access three-phase voltages;
[0024] The second ends of the transformers are respectively connected to the first AC terminal, the second AC terminal, and the third AC terminal of the off-grid inverter, and the third ends of the transformers are all connected to the neutral line of the off-grid inverter.
[0025] As a possible implementation manner, the transformer module includes: a first transformer, a second transformer, and a third transformer;
[0026] The first ends of the first transformer, the second transformer, and the third transformer are respectively connected to the voltages of the respective phases of the three-phase power grid;
[0027] The second end of the first transformer is connected to the first AC terminal of the off-grid inverter, the second end of the second transformer is connected to the second AC terminal of the off-grid inverter, and the second end of the third transformer is connected to the third AC terminal of the off-grid inverter;
[0028] The third ends of the first transformer, the second transformer, and the third transformer are all connected to the neutral line of the off-grid inverter.
[0029] As a possible implementation manner, the power conversion module further includes: a first power conversion unit and a second power conversion unit;
[0030] The AC ports of the first power conversion unit and the second power conversion unit are both used to access the three-phase power grid, and the DC port of the first power conversion unit is respectively connected to the DC port of the second power conversion unit and the DC port of the off-grid inverter;
[0031] The signal end of the first power conversion unit is connected to the signal input end of the off-grid inverter.
[0032] As a possible implementation manner, the above power quality control system further includes: an energy storage module;
[0033] The energy storage module is connected to the DC port of the second power conversion unit.
[0034] As a possible implementation, the above power quality control system further includes: a detection and monitoring module;
[0035] The detection and monitoring module is communicatively connected to the switch module, the transformer module, the power conversion module, and the energy storage module respectively.
[0036] The beneficial effects of the embodiments of the present application include:
[0037] A power quality control system provided by an embodiment of the present application forms a power quality control system through a transformer module, a power conversion module, and a switch module. The power conversion module includes an off-grid inverter. The power quality control system realizes the governance of the unbalance of the three-phase voltages of the three-phase power grid through the off-grid inverter in the power conversion module, and realizes the governance of the unbalance of the three-phase powers of the three-phase power grid through the power conversion module. Among them, one end of the transformer module is used to access the three-phase power grid, and the other end of the transformer module is connected to the AC port and the neutral line of the off-grid inverter in the power conversion module. The off-grid inverter sends three-phase compensation voltages to the transformer module through the AC port, and the transformer module adjusts the voltages of the respective phases of the three-phase power grid based on the three-phase compensation voltages so that the voltages of the respective phases of the three-phase power grid are balanced; the AC port of the off-grid inverter is also connected to the input end of the switch module, and the output end of the switch module is connected to the neutral line of the off-grid inverter. The switch module serves as a bypass circuit between the transformer module and the off-grid inverter. The control end of the switch module is connected to the signal control end of the off-grid inverter, and the off-grid inverter controls the on / off of the switch module so that the off-grid inverter is short-circuited when it is in the shutdown state or the stop state, and the high voltage of the power grid of the transformer module cannot enter the off-grid inverter, thereby achieving the purpose of protecting the power conversion module. In this way, the stability and reliability of the power quality control system can be improved. Description of the Drawings
[0038] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.
[0039] Figure 1 It is a schematic structural diagram of the first power quality control system provided by an embodiment of the present application;
[0040] Figure 2 It is a schematic structural diagram of the first switch module provided by an embodiment of the present application;
[0041] Figure 3Schematic diagram of the second switch module provided by the embodiment of the present application;
[0042] Figure 4 Schematic diagram of a transformer module provided by the embodiment of the present application;
[0043] Figure 5 Schematic diagram of a power conversion module provided by the embodiment of the present application;
[0044] Figure 6 Schematic diagram of the second power quality control system provided by the embodiment of the present application;
[0045] Figure 7 Schematic diagram of the third power quality control system provided by the embodiment of the present application.
[0046] Description of the drawings: 10: Power quality control system; 101: Transformer module; 1011: First transformer; 1012: Second transformer; 1013: Third transformer; 102: Power conversion module; 1021: First power conversion unit; 1022: Second power conversion unit; 1023: Off-grid inverter; 103: Switch module; 1031: First switch unit; 311: First electronic switch; 312: First mechanical switch; 1032: Second switch unit; 321: Second electronic switch; 322: Second mechanical switch; 1033: Third switch unit; 331: Third electronic switch; 332: Third mechanical switch; 104: Energy storage module; 105: Detection and monitoring module. Detailed implementation manners
[0047] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Apparently, the described embodiments are some but not all of the embodiments of the present application. Usually, the components of the embodiments of the present application described and illustrated herein can be arranged and designed in various different configurations.
[0048] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the present application claimed, but merely represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.
[0049] It should be noted that: Similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.
[0050] In the description of this application, it should be noted that the terms "first", "second", "third", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance. It should also be noted that unless otherwise clearly specified and defined, the terms "set", "installed", "connected", and "linked" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the connection of two components inside. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.
[0051] Currently, the UPQC system structure is usually composed of two back-to-back power converters. One end of the power converter is connected to the power grid, and the other end is connected in series to the power grid through a transformer, so that a DC bus is formed inside the UPQC system. However, when the UPQC system is used to manage the power quality of a three-phase power grid, when the series voltage compensator is in a shutdown state or not working, the high voltage of the power grid will directly damage the power converter, causing the power converter module in the power quality management system to be damaged.
[0052] Therefore, the embodiment of this application provides a power quality control system. One end of the transformer module is connected to the three-phase power grid, the AC ports of the off-grid inverter are respectively connected to the other end of the transformer module and the input end of the switch module, the other end of the transformer module and the output end of the switch module are both connected to the neutral line of the off-grid inverter, and the control end of the switch module is connected to the signal control end of the off-grid inverter. Among them, if the off-grid inverter is in a shutdown state or a power-off state, the on / off of the switch module can be controlled to short-circuit the off-grid inverter, which can avoid the damage of the high voltage of the power grid to the off-grid inverter. In this way, the stability and reliability of the power quality control system can be improved.
[0053] The following will explain in detail the power quality control system provided by the embodiment of this application with reference to the accompanying drawings.
[0054] Figure 1 For the structural schematic diagram of a power quality control system provided by this application, see Figure 1 , the embodiment of this application provides a power quality control system 10 including: a transformer module 101, a power conversion module 102, and a switch module 103, where the power conversion module 102 includes: an off-grid inverter 1023.
[0055] One end of the transformer module 101 is used to connect to the three-phase power grid, and the other end of the transformer module 101 is connected to the AC port and the neutral line of the off-grid inverter 1023 in the power conversion module 102.
[0056] Optionally, the electric energy output by the three-phase power grid includes three-phase voltage, three-phase current, and three-phase power. The three-phase currents output by the three-phase power grid are all alternating currents. One end of the transformer module 101 is used to connect to the three-phase power grid, and the transformer module 101 introduces the output electric energy of the three-phase power grid into the power quality control system 10.
[0057] Optionally, the other end of the transformer module 101 is connected to the AC port of the off-grid inverter 1023. The off-grid inverter 1023 sends three-phase compensation voltage to the transformer module 101 through the AC port, and the transformer module 101 remedies the problem of unbalanced voltages of each phase of the three-phase power grid based on the three-phase compensation voltage sent by the off-grid inverter 1023.
[0058] Optionally, the other end of the transformer module 101 is also connected to the neutral line N1 of the off-grid inverter 1023. The neutral line N1 of the off-grid inverter 1023 can provide a current loop for the transformer module 101, ensuring the safety and reliability of the operation of the transformer module 101 and providing circuit support for the off-grid inverter 1023.
[0059] Optionally, the power conversion module 102 can be implemented by multiple power converters, such as AC-DC converters, and this application does not make specific limitations in this regard. The power conversion module 102 is mainly used to remedy the problems of unbalanced three-phase voltages and unbalanced three-phase powers of the three-phase power grid. The off-grid inverter 1023 can be regarded as an implementation unit for the power conversion module 102 to remedy unbalanced three-phase voltages. The off-grid inverter 1023 is also a type of power converter, and this application does not make specific limitations in this regard.
[0060] The AC port of the off-grid inverter 1023 is also connected to the input end of the switch module 103. The output end of the switch module 103 is connected to the neutral line of the off-grid inverter 1023. The control end of the switch module 103 is respectively connected to the signal control end of the off-grid inverter 1023 and an external drive circuit.
[0061] Optionally, the AC port of the off-grid inverter 1023 is also connected to the input end of the switch module 103. The output end of the switch module 103 is connected to the neutral line of the off-grid inverter 1023. A complete loop is formed between the switch module 103 and the off-grid inverter 1023.
[0062] Optionally, the signal control terminal of the off-grid inverter 1023 is connected to the control terminal of the switch module 103. The off-grid inverter 1023 sends a switch control signal to the switch module 103 via the signal control terminal, and the switch module 103 enters a closed state or an open state in response to the switch control signal. Among them, the switch control signal sent by the off-grid inverter 1023 can either be automatically generated by the off-grid inverter 1023 based on its own operating state; or it can receive a switch control instruction issued by the upper computer and generate a corresponding switch control signal based on the received switch control instruction. This application does not make specific limitations on this.
[0063] Optionally, the AC ports of the off-grid inverter 1023 are respectively connected to the input terminal of the switch module 103 and the other end of the transformer module 101. The neutral line of the off-grid inverter 1023 is respectively connected to the output terminal of the switch module 103 and the other end of the transformer module 101. The switch module 103 and the transformer module 101 form a parallel circuit connected to the AC port of the off-grid inverter 1023, and the switch module 103 can be regarded as a bypass circuit between the transformer module 101 and the off-grid inverter 1023.
[0064] Optionally, the off-grid inverter 1023 controls the on / off of the switch module 103 through the signal control terminal, so that when the off-grid inverter 1023 is in the shutdown state or the stop state, it is short-circuited, and the grid high voltage of the transformer module 101 cannot enter the off-grid inverter 1023, thereby improving the reliability and safety of the power quality control system 10.
[0065] Optionally, the control terminal of the switch module 103 is also connected to an external drive circuit, and the user can also control the on / off of the switch module 103 through the external drive circuit. In this way, the safety and reliability of the power quality control system can be further improved.
[0066] In the embodiment of the present application, a power quality control system is composed of a transformer module, a power conversion module, and a switch module. The power conversion module includes an off-grid inverter. The power quality control system realizes the governance of the three-phase voltage imbalance of the three-phase power grid through the off-grid inverter in the power conversion module, and realizes the governance of the three-phase power imbalance of the three-phase power grid through the power conversion module. Among them, one end of the transformer module is used to connect to the three-phase power grid, and the other end of the transformer module is connected to the AC port and the neutral line of the off-grid inverter in the power conversion module. The off-grid inverter sends three-phase compensation voltages to the transformer module through the AC port, and the transformer module adjusts the voltages of each phase of the three-phase power grid based on the three-phase compensation voltages so that the voltages of each phase of the three-phase power grid are balanced; the AC port of the off-grid inverter is also connected to the input end of the switch module, and the output end of the switch module is connected to the neutral line of the off-grid inverter. The switch module serves as a bypass circuit between the transformer module and the off-grid inverter. The control end of the switch module is connected to the signal control end of the off-grid inverter. The off-grid inverter controls the on / off of the switch module so that when the off-grid inverter is in the shutdown state or the stop state, it is short-circuited, and the high voltage of the power grid of the transformer module cannot enter the off-grid inverter, thereby achieving the purpose of protecting the power conversion module. In this way, the stability and reliability of the power quality control system can be improved.
[0067] Figure 2 FIG. is a schematic structural diagram of the first switch module provided by the present application. Refer to Figure 2 In the power quality control system 10 provided in the embodiment of the present application, the switch module 103 includes: a first switch unit 1031, a second switch unit 1032, and a third switch unit 1033. The AC port of the off-grid inverter 1023 includes: a first AC end, a second AC end, and a third AC end.
[0068] Optionally, the AC port of the off-grid inverter 1023 is divided into a first AC end, a second AC end, and a third AC end. The off-grid inverter 1023 transmits the compensation voltages corresponding to the voltages of each phase of the three-phase power grid through the first AC end, the second AC end, and the third AC end respectively. For example, the first AC end is the A-phase AC end, the second AC end is the B-phase AC end, and the third AC end is the C-phase AC end. The off-grid inverter 1023 transmits the compensation voltage Ua corresponding to the A-phase voltage in the three-phase power grid through the first AC end, the off-grid inverter 1023 transmits the compensation voltage Ub corresponding to the B-phase voltage in the three-phase power grid through the second AC end, and the off-grid inverter 1023 transmits the compensation voltage Uc corresponding to the C-phase voltage in the three-phase power grid through the third AC end.
[0069] The input terminal of the first switching unit 1031 is connected to the first AC terminal of the off-grid inverter 1023. The input terminal of the second switching unit 1032 is connected to the second AC terminal of the off-grid inverter 1023. The input terminal of the third switching unit 1033 is connected to the third AC terminal of the off-grid inverter 1023.
[0070] The output terminals of the first switching unit 1031, the second switching unit 1032, and the third switching unit 1033 are all connected to the neutral line of the off-grid inverter 1023. The control terminals of the first switching unit 1031, the second switching unit 1032, and the third switching unit 1033 are all connected to the signal control terminal of the off-grid inverter 1023 and an external drive circuit.
[0071] Optionally, the input terminal of the first switching unit 1031 is connected to the first AC terminal of the off-grid inverter 1023, and the output terminal of the first switching unit 1031 is connected to the neutral line of the off-grid inverter 1023. The first switching unit 1031 is used to short-circuit the conduction and cut-off of the first AC terminal of the off-grid inverter 1023. That is, the first switching unit 1031 can be regarded as a phase A switch group, and the first switching unit 1031 is used to block or conduct the transmission of the phase A voltage of the first AC terminal of the off-grid inverter 1023.
[0072] Optionally, the input terminal of the second switching unit 1032 is connected to the second AC terminal of the off-grid inverter 1023, and the output terminal of the second switching unit 1032 is connected to the neutral line of the off-grid inverter 1023. The second switching unit 1032 is used to short-circuit the conduction and cut-off of the second AC terminal of the off-grid inverter 1023. That is, the second switching unit 1032 can be regarded as a phase B switch group, and the second switching unit 1032 is used to block or conduct the transmission of the phase B voltage of the second AC terminal of the off-grid inverter 1023.
[0073] Optionally, the input terminal of the third switching unit 1033 is connected to the third AC terminal of the off-grid inverter 1023, and the output terminal of the third switching unit 1033 is connected to the neutral line of the off-grid inverter 1023. The third switching unit 1033 is used to short-circuit the conduction and cut-off of the third AC terminal of the off-grid inverter 1023. That is, the third switching unit 1033 can be regarded as a phase C switch group, and the third switching unit 1033 is used to block or conduct the transmission of the phase C voltage of the third AC terminal of the off-grid inverter 1023.
[0074] Optionally, the control terminals of the first switch unit 1031, the second switch unit 1032, and the third switch unit 1033 are all connected to the signal control terminal of the off-grid inverter 1023. The control terminals of the first switch unit 1031, the second switch unit 1032, and the third switch unit 1033 are also used to connect to an external drive circuit. By controlling the on / off of the first switch unit 1031, the second switch unit 1032, and the third switch unit 1033 through the dual channels of the off-grid inverter 1023 and the external drive circuit, the safety and reliability of the power quality control system 10 can be further improved.
[0075] It should be noted that the switching elements of the first switch unit 1031, the second switch unit 1032, and the third switch unit 1033 are the same. The first switch unit 1031, the second switch unit 1032, and the third switch unit 1033 can share an external drive circuit, or an external drive circuit can be configured for each of the first switch unit 1031, the second switch unit 1032, and the third switch unit 1033. This application does not make specific limitations in this regard.
[0076] Figure 3 For the second structural schematic diagram of the switch module provided by this application, see Figure 3 In the switch module 103 of the power quality control system 10 provided by the embodiment of this application, the first switch unit 1031 includes: a first electronic switch 311 and a first mechanical switch 312.
[0077] Optionally, the first electronic switch 311 can be implemented by a transistor, a field effect transistor, etc., and the first mechanical switch 312 can be implemented by a contactor, a circuit breaker, a push-button switch, etc. This application does not make specific limitations in this regard.
[0078] The input terminal of the first electronic switch 311 and the input terminal of the first mechanical switch 312 are both connected to the first AC terminal of the off-grid inverter 1023, and the output terminal of the first electronic switch 311 and the output terminal of the first mechanical switch 312 are both connected to the neutral line of the off-grid inverter 1023.
[0079] The control terminal of the first electronic switch 311 is connected to the signal control terminal of the off-grid inverter 1023, and the control terminal of the first mechanical switch 312 is used to connect to an external drive circuit.
[0080] Optionally, the input ends of the first electronic switch 311 and the first mechanical switch 312 are both connected to the first AC end of the off-grid inverter 1023, and the output ends of the first electronic switch 311 and the first mechanical switch 312 are both connected to the neutral line of the off-grid inverter 1023. The first electronic switch 311 and the first mechanical switch 312 are connected in parallel to form a first switch unit 1031, and the first electronic switch 311 and the first mechanical switch 312 jointly control the conduction and cutoff of the first AC end of the off-grid inverter 1023.
[0081] Optionally, the control end of the first electronic switch 311 is connected to the signal control end of the off-grid inverter 1023. The off-grid inverter 1023 controls the closing or opening of the first electronic switch 311 through the signal control end. The control end of the first mechanical switch 312 is used to access an external drive circuit, and the user triggers the closing or opening of the first mechanical switch 312 through the external drive circuit.
[0082] In a possible implementation, refer to Figure 3 , the second switch unit 1032 in the switch module 103 of the power quality control system 10 provided by the embodiment of the present application includes: a second electronic switch 321 and a second mechanical switch 322.
[0083] Optionally, the second electronic switch 321 can be implemented by a transistor, a field effect transistor, etc., and the second mechanical switch 322 can be implemented by a contactor, a circuit breaker, a push-button switch, etc. The present application does not make specific limitations on this.
[0084] The input ends of the second electronic switch 321 and the second mechanical switch 322 are both connected to the second AC end of the off-grid inverter 1023, and the output ends of the second electronic switch 321 and the second mechanical switch 322 are both connected to the neutral line of the off-grid inverter 1023.
[0085] The control end of the second electronic switch 321 is connected to the signal control end of the off-grid inverter 1023, and the control end of the second mechanical switch 322 is used to access an external drive circuit.
[0086] Optionally, the input ends of the second electronic switch 321 and the second mechanical switch 322 are both connected to the second AC end of the off-grid inverter 1023, and the output ends of the second electronic switch 321 and the second mechanical switch 322 are both connected to the neutral line of the off-grid inverter 1023. The second electronic switch 321 and the second mechanical switch 322 are connected in parallel to form a second switch unit 1032, and the second electronic switch 321 and the second mechanical switch 322 jointly control the conduction and cutoff of the second AC end of the off-grid inverter 1023.
[0087] Optionally, the control terminal of the second electronic switch 321 is connected to the signal control terminal of the off-grid inverter 1023. The off-grid inverter 1023 controls the closing or opening of the second electronic switch 321 through the signal control terminal. The control terminal of the second mechanical switch 322 is used to connect to an external drive circuit, and the user triggers the closing or opening of the second mechanical switch 322 through the external drive circuit.
[0088] In a possible implementation, refer to Figure 3 , the third switch unit 1033 in the switch module 103 of the power quality control system 10 provided by the embodiment of the present application includes: a third electronic switch 331 and a third mechanical switch 332.
[0089] Optionally, the third electronic switch 331 can be implemented by a transistor, a field effect transistor, etc., and the third mechanical switch 332 can be implemented by a contactor, a circuit breaker, a push-button switch, etc. The present application does not make specific limitations on this.
[0090] The input terminal of the third electronic switch 331 and the input terminal of the third mechanical switch 332 are both connected to the third AC terminal of the off-grid inverter 1023, and the output terminal of the third electronic switch 331 and the output terminal of the third mechanical switch 332 are both connected to the neutral line of the off-grid inverter 1023.
[0091] The control terminal of the third electronic switch 331 is connected to the signal control terminal of the off-grid inverter 1023, and the control terminal of the third mechanical switch 332 is used to connect to an external drive circuit.
[0092] Optionally, the input terminal of the third electronic switch 331 and the input terminal of the third mechanical switch 332 are both connected to the third AC terminal of the off-grid inverter 1023, and the output terminal of the third electronic switch 331 and the output terminal of the third mechanical switch 332 are both connected to the neutral line of the off-grid inverter 1023. The third electronic switch 331 and the third mechanical switch 332 are connected in parallel to form the third switch unit 1033, and the third electronic switch 331 and the third mechanical switch 332 jointly control the conduction and cutoff of the third AC terminal of the off-grid inverter 1023.
[0093] Optionally, the control terminal of the third electronic switch 331 is connected to the signal control terminal of the off-grid inverter 1023. The off-grid inverter 1023 controls the closing or opening of the third electronic switch 331 through the signal control terminal. The control terminal of the third mechanical switch 332 is used to connect to an external drive circuit, and the user triggers the closing or opening of the third mechanical switch 332 through the external drive circuit.
[0094] In a possible implementation, the transformer module 101 in the power quality control system 10 provided by the embodiment of the present application includes: at least one transformer.
[0095] The first ends of the transformers are used to connect to three-phase voltages.
[0096] Optionally, the first ends of the transformers are used to connect to three-phase voltages. Each transformer performs voltage equalization control on each phase voltage of the three-phase power grid, and the voltage equalization controls of each transformer on each phase voltage of the three-phase power grid do not interfere with each other.
[0097] The second ends of the transformers are respectively connected to the first AC end, the second AC end, and the third AC end of the off-grid inverter 1023, and the third ends of the transformers are all connected to the neutral line of the off-grid inverter 1023.
[0098] Optionally, the second ends of the transformers are respectively connected to the first AC end, the second AC end, and the third AC end of the off-grid inverter 1023. Each transformer accesses the three-phase compensation voltage output from the AC ports of the off-grid inverter 1023 via the second ends, the third ends of the transformers are all connected to the neutral line of the off-grid inverter 1023, and a complete current loop is formed between each transformer and the off-grid inverter 1023.
[0099] Figure 4 It is a schematic structural diagram of a transformer module provided by this application. Refer to Figure 4 , the transformer module 101 in the power quality control system 10 provided by the embodiments of this application includes: a first transformer 1011, a second transformer 1012, and a third transformer 1013.
[0100] The first ends of the first transformer 1011, the second transformer 1012, and the third transformer 1013 are respectively connected to each phase voltage of the three-phase power grid.
[0101] Optionally, the first ends of the first transformer 1011, the second transformer 1012, and the third transformer 1013 are respectively connected to each phase voltage of the three-phase power grid. For example, the first end of the first transformer 1011 is connected to the A-phase voltage of the three-phase power grid, the first end of the second transformer 1012 is connected to the B-phase voltage of the three-phase power grid, and the first end of the third transformer 1013 is connected to the C-phase voltage of the three-phase power grid. This application does not make specific limitations on this.
[0102] The second end of the first transformer 1011 is connected to the first AC end of the off-grid inverter 1023, the second end of the second transformer 1012 is connected to the second AC end of the off-grid inverter 1023, and the second end of the third transformer 1013 is connected to the third AC end of the off-grid inverter 1023.
[0103] Optionally, the second end of the first transformer 1011 is connected to the first AC end of the off-grid inverter 1023, the second end of the second transformer 1012 is connected to the second AC end of the off-grid inverter 1023, and the second end of the third transformer 1013 is connected to the third AC end of the off-grid inverter 1023. That is, each transformer in the transformer module 101 receives the compensation voltage corresponding to each phase voltage output by the off-grid inverter 1023 via its second end. For example, the second end of the first transformer 1011 is used to receive the compensation voltage Ua corresponding to the A-phase voltage output by the off-grid inverter 1023, the second end of the second transformer 1012 is used to receive the compensation voltage Ub corresponding to the B-phase voltage output by the off-grid inverter 1023, and the second end of the third transformer 1013 is used to receive the compensation voltage Uc corresponding to the C-phase voltage output by the off-grid inverter 1023.
[0104] The third ends of the first transformer 1011, the second transformer 1012, and the third transformer 1013 are all connected to the neutral line of the off-grid inverter 1023.
[0105] Optionally, the third ends of the first transformer 1011, the second transformer 1012, and the third transformer 1013 are all connected to the neutral line of the off-grid inverter 1023. That is, a complete loop is formed between each transformer in the transformer module 101 and the off-grid inverter 1023.
[0106] Figure 5 It is a schematic structural diagram of a power conversion module provided by this application. Refer to Figure 5 In addition, the power conversion module 102 in the power quality control system 10 provided by the embodiment of this application further includes: a first power conversion unit 1021 and a second power conversion unit 1022.
[0107] The AC ports of the first power conversion unit 1021 and the second power conversion unit 1022 are both used to access the three-phase power grid. The DC port of the first power conversion unit 1021 is respectively connected to the DC port of the second power conversion unit 1022 and the DC port of the off-grid inverter 1023.
[0108] Optionally, the power conversion module 102 obtains the electric energy of each phase of the three-phase power grid via the AC port of the first power conversion unit 1021. The electric energy of each phase includes the voltage and current of each phase. The first power conversion unit 1021 converts the received electric energy of each phase into direct current, and the first power conversion unit 1021 transmits the direct current to the second power conversion unit 1022 and the off-grid inverter 1023 via the DC port. Among them, the second power conversion unit 1022 receives the direct current provided by the first power conversion unit 1021 via the DC port, and the off-grid inverter 1023 receives the direct current provided by the first power conversion unit 1021 via the DC port.
[0109] Optionally, the AC port of the second power conversion unit 1022 is used to access the three-phase power grid. The second power conversion unit 1022 can collect the power of each phase of the three-phase power grid in real time through the AC port, and output the compensation current corresponding to the current of each phase to the three-phase power grid based on the direct current output by the first power conversion unit 1021, so as to achieve the balance of the power of each phase of the three-phase power grid.
[0110] The signal terminal of the first power conversion unit 1021 is connected to the signal input terminal of the off-grid inverter 1023.
[0111] Optionally, the signal terminal of the first power conversion unit 1021 is connected to the signal input terminal of the off-grid inverter 1023. The first power conversion unit 1021 sends a phase synchronization signal to the off-grid inverter 1023 via the signal terminal. The phase synchronization signal is used to indicate a signal synchronized with the phase of each phase voltage of the three-phase power grid. The off-grid inverter 1023 synchronously outputs three-phase compensation voltage to the transformer module 101 based on the phase synchronization signal received at the signal input terminal.
[0112] Figure 6 This is a schematic structural diagram of the second power quality control system provided by the present application. Refer to Figure 6 In addition, the power quality control system 10 provided by the embodiment of the present application further includes: an energy storage module 104.
[0113] The energy storage module 104 is connected to the DC port of the second power conversion unit 1022.
[0114] Optionally, the energy storage module 104 can be implemented by an energy storage battery, a power management chip, etc. The energy storage module 104 is connected to the DC port of the second power conversion unit 1022. The energy storage module 104 can supply power to the second power conversion unit 1022, and the energy storage module 104 serves as an auxiliary power supply for the second power conversion unit 1022.
[0115] Optionally, the energy storage module 104 in the power quality control system 10 is an optional electronic component. The power quality control system 10 can either be provided with the energy storage module 104 or not. Whether there is an energy storage module 104 does not affect the performance of the power quality control system 10.
[0116] Figure 7 This is a schematic structural diagram of the third power quality control system provided by the present application. Refer to Figure 7 In addition, the power quality control system 10 provided by the embodiment of the present application further includes: a detection and monitoring module 105.
[0117] The detection and monitoring module 105 is communicatively connected to the switch module 103, the transformer module 101, the power conversion module 102, and the energy storage module 104 respectively.
[0118] Optionally, the detection and monitoring module 105 can be implemented by a microcontroller, a chip, a sensor, etc., and the present application does not make specific limitations thereon.
[0119] Optionally, the detection and monitoring module 105 is communicatively connected to the switch module 103, the transformer module 101, the power conversion module 102, and the energy storage module 104 respectively. The detection and monitoring module 105 can monitor the working states of the switch module 103, the transformer module 101, the power conversion module 102, and the energy storage module 104 in real time, and issue corresponding control instructions based on the real-time working states of the switch module 103, the transformer module 101, the power conversion module 102, and the energy storage module 104, so as to enable the power quality control system 10 to operate safely and stably.
[0120] The above are only specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present application, and all of them should be covered by the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.
[0121] The above are only the preferred embodiments of the present application and are not used to limit the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims
1. A power quality control system, characterized in that, The power quality control system includes: a transformer module, a power conversion module, and a switch module. The power conversion module includes: an off-grid inverter; One end of the transformer module is used to connect to a three-phase power grid, and the other end of the transformer module is connected to the AC port and the neutral line of the off-grid inverter in the power conversion module; The AC port of the off-grid inverter is also connected to the input end of the switch module. The output end of the switch module is connected to the neutral line of the off-grid inverter, and the control end of the switch module is respectively connected to the signal control end of the off-grid inverter and an external drive circuit.
2. The power quality control system according to claim 1, characterized in that The switch module includes: a first switch unit, a second switch unit, and a third switch unit. The AC port of the off-grid inverter includes: a first AC end, a second AC end, and a third AC end; The input end of the first switch unit is connected to the first AC end of the off-grid inverter. The input end of the second switch unit is connected to the second AC end of the off-grid inverter. The input end of the third switch unit is connected to the third AC end of the off-grid inverter; The output ends of the first switch unit, the second switch unit, and the third switch unit are all connected to the neutral line of the off-grid inverter. The control ends of the first switch unit, the second switch unit, and the third switch unit are all connected to the signal control end of the off-grid inverter and an external drive circuit.
3. The power quality control system according to claim 2, characterized in that The first switch unit includes: a first electronic switch and a first mechanical switch; The input end of the first electronic switch and the input end of the first mechanical switch are both connected to the first AC end of the off-grid inverter. The output end of the first electronic switch and the output end of the first mechanical switch are both connected to the neutral line of the off-grid inverter; The control end of the first electronic switch is connected to the signal control end of the off-grid inverter. The control end of the first mechanical switch is used to connect to an external drive circuit.
4. The power quality control system according to claim 2, characterized in that The second switch unit includes: a second electronic switch and a second mechanical switch; The input end of the second electronic switch and the input end of the second mechanical switch are both connected to the second AC end of the off-grid inverter. The output end of the second electronic switch and the output end of the second mechanical switch are both connected to the neutral line of the off-grid inverter; The control end of the second electronic switch is connected to the signal control end of the off-grid inverter. The control end of the second mechanical switch is used to connect to an external drive circuit.
5. The power quality control system according to claim 2, characterized in that The third switch unit includes: a third electronic switch and a third mechanical switch; The input end of the third electronic switch and the input end of the third mechanical switch are both connected to the third AC end of the off-grid inverter. The output end of the third electronic switch and the output end of the third mechanical switch are both connected to the neutral line of the off-grid inverter; The control end of the third electronic switch is connected to the signal control end of the off-grid inverter. The control end of the third mechanical switch is used to connect to an external drive circuit.
6. The power quality control system according to claim 2, wherein The transformer module includes: at least one transformer; The first end of each transformer is used to connect to a three-phase voltage; The second ends of the respective transformers are respectively connected to the first AC terminal, the second AC terminal, and the third AC terminal of the off-grid inverter, and the third ends of the respective transformers are all connected to the neutral line of the off-grid inverter.
7. The power quality control system according to claim 6, characterized in that The transformer module includes: a first transformer, a second transformer, and a third transformer; The first ends of the first transformer, the second transformer, and the third transformer are respectively connected to the respective phase voltages of the three-phase power grid; The second end of the first transformer is connected to the first AC terminal of the off-grid inverter, the second end of the second transformer is connected to the second AC terminal of the off-grid inverter, and the second end of the third transformer is connected to the third AC terminal of the off-grid inverter; The third ends of the first transformer, the second transformer, and the third transformer are all connected to the neutral line of the off-grid inverter.
8. The power quality control system according to claim 1, wherein The power conversion module further includes: a first power conversion unit and a second power conversion unit; The AC ports of the first power conversion unit and the second power conversion unit are both used to connect to the three-phase power grid, and the DC port of the first power conversion unit is respectively connected to the DC port of the second power conversion unit and the DC port of the off-grid inverter; The signal end of the first power conversion unit is connected to the signal input end of the off-grid inverter.
9. The power quality control system according to claim 8, characterized in that, The power quality control system further includes: an energy storage module; The energy storage module is connected to the DC port of the second power conversion unit.
10. The power quality control system according to claim 9, characterized in that, The power quality control system further includes: a detection and monitoring module; The detection and monitoring module is respectively communicatively connected to the switch module, the transformer module, the power conversion module, and the energy storage module.