A hybrid transfer switch for source switching in a light storage microgrid and a control method thereof

Abstract

The application discloses a hybrid transfer switch for switching between light storage micro-grid sources and a control method, and belongs to the technical field of switching between light storage micro-grid sources. The hybrid transfer switch comprises a first source input end, a second source input end, a first source side switch assembly, a second source side switch assembly and a control module. The first source side switch assembly and the second source side switch assembly are both provided with a mechanical through-flow branch, a power electronic transient branch and an absorption branch. The mechanical through-flow branch is used for steady-state through-flow and breaking of fault current in case of failure. The power electronic transient branch is used for short-time conduction and current transfer during switching between sources. The absorption branch is used for inhibiting transient overvoltage. The control module is used for judging operating conditions, and controls the power electronic transient branch and the mechanical through-flow branch to act in cooperation in case of normal switching, and blocks the power electronic transient branch and breaks the fault current by the mechanical through-flow branch in case of failure. The application can reduce switching impact and contact ablation, and improve the reliability of switching between sources.

Description

Technical Field

[0001] This invention relates to the field of power source switching technology in photovoltaic-storage microgrids, and more specifically to a hybrid switching switch and control method for power source switching in photovoltaic-storage microgrids. Background Technology

[0002] With the rapid development of distributed photovoltaic (PV), commercial and industrial energy storage, charging facilities, and microgrid systems, the trend of shifting from single-source power supply to multi-source collaborative power supply in low-voltage power distribution systems is becoming increasingly apparent. In PV-storage microgrids, grid-connected, off-grid, and source-to-source switching operations are frequently required between energy storage inverter units, the low-voltage AC grid, and sensitive loads. When a power source experiences voltage dips, short-term interruptions, phase loss, frequency anomalies, or fault disturbances, it is necessary to quickly transfer sensitive loads to another power source to reduce the impact of short-term power outages, voltage surges, and load loss on production equipment and the power system. Therefore, fast-transfer switches between sources not only need high current-carrying capacity and fault-breaking capacity, but also require low-impact, low-loss, controllable operating phase, and monitorable operating status. Existing fast-transfer switches between sources mainly fall into three categories:

[0003] First, low-voltage dual-power transfer switches: These typically use mechanical switches, contactors, or ordinary circuit breakers for power switching. While their structure is mature and their current loss is low, their mechanical action time is relatively long. The opening and closing process is significantly affected by the contact movement speed, the consistency of the spring mechanism, and arc burning, making it difficult to meet the millisecond-level switching and phase-controllable closing requirements of sensitive loads in photovoltaic-storage microgrids. When there are differences in the phase, frequency, or voltage amplitude of the two power sources, relying solely on low-voltage dual-power transfer switches can easily generate large closing inrush currents and voltage disturbances, leading to inverter unit protection activation or abnormal operation of sensitive loads.

[0004] Second, solid-state power electronic switches, such as solid-state transfer switches and solid-state grid-connected switches, while capable of rapid turn-on and turn-off, suffer from problems such as high conduction losses, high heat dissipation requirements, high cost, and limited short-circuit withstand capability due to the long-term flow of main current through power semiconductor devices during steady-state operation. For switching scenarios between photovoltaic and energy storage microgrids, relying entirely on IGBTs, thyristors, or other power electronic devices in solid-state power electronic switches for long-term current carrying and fault clearing would increase the difficulty of system thermal design and device series-parallel design, and could lead to risks of device overheating, overvoltage, or turn-off failure under high-current short-circuit faults.

[0005] Third, hybrid switches: These switches typically connect mechanical switches in parallel with power electronic branches. The power electronic branches enable commutation or auxiliary shutdown, while the mechanical switches reduce steady-state losses. This type of solution can balance speed and low loss to some extent, but it primarily targets DC circuit breakers, high-voltage hybrid switches, or general power switching devices. Its focus is on fault current commutation, solid-state branch shutdown, or energy absorption. It does not fully consider the three-phase phase relationship between the first and second sources in a low-voltage photovoltaic-storage microgrid, the zero-crossing moment of the load current, the instantaneous voltage difference between the source to be connected and the residual voltage of the bus, and the impact of the mechanical operating mechanism's action delay on the target opening and closing phases. While some microgrid grid connection point fast switching schemes using hybrid switches can achieve rapid establishment or isolation between the distribution network and the microgrid, they mainly address the problem of rapid switching of grid connection points. They do not form a phase-controllable residual magnetism hybrid fast switching structure for switching between two sources, nor do they clearly divide the steady-state current carrying and fault independent interruption functions of mechanical current-carrying branches with the short-time commutation functions of power electronic transient branches.

[0006] Furthermore, existing mechanical operating mechanisms mostly employ spring mechanisms, electromagnetic mechanisms, or repulsion mechanisms. Spring mechanisms have numerous mechanical parts, limiting the consistency of action and long-term maintainability; traditional electromagnetic mechanisms have high energy consumption; and while repulsion mechanisms offer fast operating speeds, they suffer from large drive currents, strong impacts, and significant challenges in buffering and reliability design. Residual magnetism-based magnetic control mechanisms offer advantages such as compact structure, low energy consumption, and fast response; however, existing residual magnetism mechanisms are primarily used as single circuit breaker operating mechanisms and have not yet been fully integrated with target opening and closing phases, short-term conduction of power electronic transient branches, steady-state current carrying capacity of mechanical current-carrying branches, and fault interruption strategies during switching between photovoltaic and energy storage microgrid sources.

[0007] Therefore, existing technologies still have the following shortcomings: First, mechanical transfer switches have insufficient operating speed and phase controllability, making them prone to closing impacts and switching arcs; second, solid-state transfer switches have high long-term current losses and heat loads, limiting their ability to withstand short-circuit faults; third, existing hybrid switches focus more on the converter topology itself, with insufficient consideration for phase controllable switching between the two power sources of the photovoltaic-storage microgrid, mechanical action delay correction, and source-side interlocking control; fourth, there is insufficient comprehensive detection of operating information such as contact pressure, IGBT temperature, vacuum status of the vacuum arc extinguishing component, and opening and closing coil drive status, making it difficult to promptly identify abnormal mechanical contact, branch overheating, vacuum deterioration, or abnormal mechanism operation. Summary of the Invention

[0008] In view of the above problems, the present invention is proposed to provide a hybrid switching switch and control method for switching between photovoltaic and energy storage microgrid sources to overcome or at least partially solve the above problems.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, embodiments of the present invention provide a hybrid transfer switch for switching between sources in a photovoltaic-storage microgrid, comprising a first source input terminal, a first source-side switch assembly, a second source input terminal, a second source-side switch assembly, and a control module; The first source-side switch assembly is connected between the first source input terminal and the three-phase AC bus, and is used to connect or disconnect the path between the first source input terminal in the low-voltage AC power supply and the grid load; The second source-side switch assembly is connected between the second source input terminal and the three-phase AC bus, and is used to connect or disconnect the path between the second source input terminal in the low-voltage AC power supply and the grid load; The first source-side switching assembly and the second source-side switching assembly are each provided with a mechanical current-carrying branch, a power electronic transient branch and an absorption branch connected in parallel; The control module, connected to the first source-side switch assembly, the second source-side switch assembly, and the three-phase AC bus, is configured to: Determine whether the photovoltaic-storage microgrid is in fault operation condition based on the three-phase voltage signal and the three-phase current signal; If the system is in a fault operation condition, the power electronic transient branch of the first source-side switch assembly and the second source-side switch assembly is blocked, and the mechanical current-carrying branch is controlled to interrupt the fault current. If not in fault operation condition, determine whether in source switching condition, and generate interlock signal when in source switching condition, and control the mechanical current-carrying branch of the first source-side switch assembly or the second source-side switch assembly to perform opening and closing actions, short-term conduction of power electronic transient branch, and control the absorption branch to suppress transient overvoltage; the interlock signal is used to control the interlock between the first source-side switch assembly and the second source-side switch assembly. When the source-to-source switching is completed and the system enters a steady-state operating condition, the mechanical current-passing branch of the first source-side switching assembly or the second source-side switching assembly on the control operating side is turned on.

[0010] In one embodiment, the mechanical flow path includes: Arc extinguishing components are used to extinguish or cut off electric arcs; The residual magnet type magnetic control mechanism is connected to the arc extinguishing component and includes an insulating pull rod, a contact spring, a tripping spring, a bracket, a static magnetic core, a pressure strain gauge, two tripping coils, a moving magnetic core, and a limit block. One end of the insulating pull rod is connected to the arc extinguishing component in a transmission manner; The contact spring is sleeved on the tie rod and is used to generate contact pressure when the first source-side switch assembly or the second source-side switch assembly is in the closing process. The opening spring is sleeved outside the contact spring and is used to provide opening driving force when the first source-side switch assembly or the second source-side switch assembly is in the process of opening; The bracket has a stationary magnetic core and a moving magnetic core arranged opposite to each other, and the stationary magnetic core and the moving magnetic core are provided with two side grooves and a central groove for placing the contact spring and the opening spring. The bracket is slidably connected to the insulating pull rod through the contact spring and the opening spring. The pressure strain gauge is disposed at the bottom of the moving magnetic core and is used to detect the contact pressure generated when the spring assembly is pressed downward. The two opening and closing coils are respectively disposed in the two side grooves to receive opening and closing pulses and drive the moving magnetic core to move; The limiting block is located at the bottom of the moving magnetic core. The insulating pull rod passes through the contact spring and the opening spring and is fixedly connected to the moving magnetic core and the limiting block to limit the movement stroke of the moving magnetic core.

[0011] In one embodiment, both the stationary magnetic core and the moving magnetic core are semi-hard magnetic materials.

[0012] In one embodiment, when the arc-extinguishing assembly is a vacuum arc-extinguishing assembly, the vacuum arc-extinguishing assembly includes: Vacuum arc extinguishing assembly housing; A vacuum static conductive rod is fixedly connected to the housing of the vacuum arc extinguishing assembly. A vacuum stationary contact is disposed within the housing of the vacuum arc-extinguishing assembly; A vacuum moving contact is disposed inside the housing of the vacuum arc extinguishing assembly and is positioned opposite to the vacuum stationary contact. The vacuum moving conductive rod is connected to the vacuum moving contact, and forms a movable sealed connection with the vacuum arc extinguishing component housing through the metal bellows inside the vacuum arc extinguishing component housing, and is also connected to the insulating pull rod for transmission.

[0013] In one embodiment, when the arc-extinguishing component is an air arc-extinguishing component, the air arc-extinguishing component includes: The air arc extinguishing assembly housing includes an arc extinguishing grid support assembly, a rotatable moving contact arm, and an exhaust channel; An air-operated contact is disposed at the rotating end of the movable contact arm; The air-powered conductive rod has one end connected to the fixed end of the moving contact arm, and the other end passes through the housing of the air arc extinguishing assembly and is connected to the insulating pull rod. An air stationary contact is fixedly installed on one side inside the housing of the air arc extinguishing assembly and is positioned opposite to the air moving contact. Multiple metal arc-extinguishing grid plates are mounted on the arc-extinguishing grid plate support assembly, and form an arc-extinguishing grid inlet with an opening facing the contact area above the air stationary contact and the air moving contact; the exhaust channel is connected to the upper part of the metal arc-extinguishing grid plates and is used to discharge the high-temperature gas generated during the breaking process.

[0014] In one embodiment, the power electronic transient branch includes a bidirectional controllable power switching unit composed of at least two IGBT power devices, wherein the IGBT power devices include: A surface-mount temperature sensor is electrically connected to the control module.

[0015] In one embodiment, the control module includes: The IGBT temperature detection unit is connected to the power electronic transient branch and is used to collect the temperature signal in the power electronic transient branch; The IGBT drive unit is connected to the power electronic transient branch and is used to drive or block the IGBT power device. A coil driving unit, connected to the opening and closing coil, is used to output opening and closing driving pulses to drive the opening and closing coil; A holding force detection unit, connected to the pressure strain gauge, is used to collect contact pressure or residual magnetism holding force status signals; The current detection unit is connected to the first source input terminal, the second source input terminal and the three-phase AC bus, and is used to collect the current signals corresponding to the first source input terminal, the second source input terminal and the three-phase AC bus. The voltage detection unit is connected to the first source input terminal, the second source input terminal and the three-phase AC bus, and is used to collect the three-phase voltage signals of the first source input terminal, the second source input terminal and the three-phase AC bus. A vacuum detection unit, electrically connected to the arc-extinguishing assembly, is used to determine the vacuum state of the arc-extinguishing assembly when the arc-extinguishing assembly is a vacuum arc-extinguishing assembly. The control unit is electrically connected to the IGBT temperature detection unit, IGBT drive unit, coil drive unit, holding force detection unit, current detection unit, voltage detection unit and vacuum detection unit, and receives the acquired signals; The power supply unit is connected to the three-phase AC bus of the control unit, the first source input terminal and / or the second source input terminal, and is used to supply power to the control unit, the IGBT temperature detection unit, the IGBT drive unit, the coil drive unit, the holding force detection unit, the current detection unit, the voltage detection unit and the vacuum detection unit.

[0016] In a second aspect, embodiments of the present invention provide a control method for a hybrid transfer switch for switching between power sources in a photovoltaic-storage microgrid, applied to a hybrid transfer switch for switching between power sources in a photovoltaic-storage microgrid as described in the first aspect, comprising the following steps: S1: The control module acquires the three-phase voltage signal and three-phase current signal corresponding to the first source input terminal, the second source input terminal, and the three-phase AC bus, respectively; S2: The control module determines whether the photovoltaic-storage microgrid is in a fault operation condition based on the three-phase voltage signal and the three-phase current signal. S3: If the photovoltaic-storage microgrid is in a fault operation condition, the control module blocks the power electronic transient branch and controls the mechanical current-carrying branch on the operating side to interrupt the fault current. S4: If the photovoltaic-storage microgrid is not in a fault operation condition, the control module determines whether it is in an inter-source switching condition, and generates an interlock signal when it is in an inter-source switching condition, and controls the mechanical current-carrying branch of the first source-side switching component or the second source-side switching component to perform opening and closing actions, short-term conduction of the power electronic transient branch, control the absorption branch to suppress transient overvoltage, and control the mechanical current-carrying branch to conduct. S5: When the source-to-source switching is completed and the system enters steady-state operation, the mechanical current-passing branch of the first source-side switching component or the second source-side switching component on the control operation side is turned on.

[0017] In one embodiment, step S4 includes: When in the inter-source switching condition, the control module controls the power electronic transient branch of the source to be cut off to be turned on for a short time, controls the mechanical current-carrying branch to perform the opening action at the target opening phase, and controls the absorption branch to suppress transient overvoltage, and determines whether the first safety turn-off constraint condition is met. Determine whether the current has been transferred to the power electronic transient branch and whether the contact movement distance of the arc extinguishing component of the mechanical current-carrying branch is not less than the effective distance; If the current is transferred to the power electronic transient branch and the contact movement distance is not less than the effective distance, then determine whether the current has crossed zero, or whether the first safety turn-off condition is met. If the current crosses zero, or if the first safety shutdown condition is met, the control module controls the power electronic transient branch of the first source-side component or the second source-side switching component of the source to be connected to conduct for a short time, controls the mechanical current-carrying branch to perform a closing action at the target closing phase, and controls the absorption branch to suppress transient overvoltage. Determine that the contact pressure of the arc-extinguishing component in the mechanical current-passing branch is greater than the pressure threshold and that the current is transferred to the mechanical current-passing branch of the first source-side component or the second source-side switching component of the source to be connected. If the contact pressure is greater than the pressure threshold, and the current is transferred to the mechanical current-carrying branch of the first source-side component or the second source-side switching component of the source to be connected, then the power electronic transient branch of the source to be connected is turned off, and the system enters the steady-state operating condition.

[0018] In one embodiment, the target closing phase determination step and the target opening phase determination step include: The zero-crossing time of the current of the source to be cut off and the preset opening delay of the mechanical current-carrying branch are obtained, and the target opening phase is determined according to the zero-crossing time of the current and the preset opening delay. The voltage difference between the voltage of the source to be connected and the voltage on the receiving side is calculated in real time, and the target closing phase is determined based on the voltage difference, the voltage difference threshold and the preset closing delay.

[0019] The beneficial effects of the above-described technical solutions provided in the embodiments of the present invention include at least the following: 1. This invention adopts a hybrid structure in which mechanical current-carrying branches and power electronic transient branches are connected in parallel. During steady-state operation, the mechanical current-carrying branch bears the main circuit current, which reduces the long-term current loss and heat dissipation pressure of power devices. During normal inter-source switching, the power electronic transient branch is briefly turned on and assists in current transfer, which improves the opening and closing speed and reduces the switching impact.

[0020] 2. This invention combines a residual magnetism control mechanism with an arc-extinguishing component to form a mechanical current-carrying branch. This allows the residual magnetism control mechanism to achieve low-energy maintenance and rapid operation, while the arc-extinguishing component can undertake long-term current carrying and fault interruption functions, thus avoiding the problem of relying entirely on IGBT power devices to interrupt fault current during overload or short-circuit faults.

[0021] 3. Based on the voltage amplitude, frequency, phase sequence, zero-crossing time and phase angle of the first source, the second source and the three-phase AC bus, as well as the zero-crossing time of the load current and the predicted action delay of the residual magnetism control mechanism, the present invention determines the target opening phase and the target closing phase, which can reduce the instantaneous voltage difference and closing impact during the switching process of the two power sources and realize phase-controllable fast inter-source switching.

[0022] 4. This invention blocks the transient branch of the power electronics and prohibits the activation of the backup power source under short-circuit fault conditions. The fault current is interrupted by the mechanical current-carrying branch corresponding to the current source, which improves the safety of fault handling and reduces the risk of thermal damage and failure of IGBT power devices under high current faults.

[0023] 5. This invention achieves comprehensive monitoring of the mechanical branch, power electronic branch, and arc extinguishing component status through IGBT temperature detection, contact pressure or residual magnetism holding force detection, vacuum status detection, opening and closing coil drive current detection, and voltage and current detection. It can promptly identify abnormal contact, branch overheating, vacuum deterioration, and abnormal mechanism operation, thereby improving the operational reliability and maintenance convenience of the fast transfer switch. Attached Figure Description

[0024] 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 embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of a hybrid switching circuit topology for switching between power sources in a photovoltaic-storage microgrid, provided in an embodiment of the present invention. 10-First source input terminal; 20-First source side switch assembly; 21-Mechanical current-carrying branch; 211-Arc extinguishing assembly; 2110-Vacuum arc extinguishing assembly housing; 2111-Vacuum stationary conductive rod; 2112-Vacuum stationary contact; 2113-Vacuum moving contact; 2114-Vacuum moving conductive rod; 2115-Metal bellows; 2116-Air moving contact; 2117-Air moving conductive rod; 2118-Air stationary contact; 2119-Metal arc extinguishing grid; 212-Residual magnetization type magnetic control mechanism; 2121-Insulating pull rod; 2122-Contact spring; 2123-Breaking spring; 2124-Bracket; 2125-Stationary magnetic core; 2126-Pressure... Force strain gauge; 2127-Two opening and closing coils; 2128-Moving magnetic core; 2129-Limit block; 22-Power electronic transient branch; 221-IGBT power device; 222-Surface mount temperature sensor; 23-Absorption branch; 30-Control module; 301-IGBT temperature detection unit; 302-IGBT drive unit; 303-Coil drive unit; 304-Holding force detection unit; 305-Current detection unit; 306-Voltage detection unit; 307-Vacuum detection unit; 308-Power supply unit; 309-Rogowski coil; 40-Second source input terminal; 50-Second source side switching assembly; 60-Sensitive load; Figure 2 This is a schematic diagram of a single-phase structure of a phase-controllable residual magnetism hybrid fast transfer switch provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the vacuum arc-extinguishing assembly provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of the air arc extinguishing assembly provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of the phase-controllable residual magnetism hybrid fast switching switch control module provided in an embodiment of the present invention; Figure 6 This is an illustration of an application scenario for the phase-controllable residual magnetism hybrid fast transfer switch provided in an embodiment of the present invention; Figure 7 This is a flowchart of the phase-controllable residual magnetism hybrid fast switching switch control method provided in an embodiment of the present invention. Detailed Implementation

[0026] 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.

[0027] Example 1: like Figure 1 As shown in the figure, an embodiment of the present invention discloses a hybrid transfer switch for switching between sources in a photovoltaic-storage microgrid, including a first source input terminal 10, a second source input terminal 40, a first source-side switch assembly 20, a second source-side switch assembly 50, a control module 30, and a sensitive load 60.

[0028] (1) First source input terminal 10 and second source input terminal 40 Specifically, the first source input terminal 10 is connected to the first source-side switch assembly 20, and the second source input terminal 40 is connected to the second source-side switch assembly 50.

[0029] Both the first source input terminal 10 and the second source input terminal 40 can be connected to a low-voltage AC power grid, the output terminal of an energy storage inverter, the output terminal of a photovoltaic energy storage charging system, or other low-voltage AC power sources.

[0030] (2) First source-side switching assembly 20 and second source-side switching assembly 50 Specifically, the first source-side switch assembly 20 is connected between the first source input terminal 10 and the three-phase AC bus; the second source-side switch assembly 50 is connected between the second source input terminal 40 and the three-phase AC bus.

[0031] In this embodiment of the invention, both the first source-side switching assembly 20 and the second source-side switching assembly 50 are provided with three single-phase fast switching units, that is, the three single-phase fast switching units together constitute the first source-side switching assembly 20; the three single-phase fast switching units of the first source-side switching assembly 20 correspond to phase A, phase B and phase C of the three-phase AC circuit, respectively, and in this embodiment of the invention, the structures of the three single-phase fast units can be the same.

[0032] Each single-phase fast switching unit is equipped with a mechanical current-carrying branch 21, a power electronic transient branch 22, and an absorption branch 23, such as Figure 2 The diagram shown is a structural schematic of a one-phase fast switching unit provided in an embodiment of the present invention.

[0033] (2-1) The mechanical current-carrying branch 21 includes an arc-extinguishing component 211 and a residual magnet magnetic control mechanism 212 that is drivenly connected to the arc-extinguishing component 211. It is used to bear the main circuit current of the phase in steady-state operation and to independently interrupt the fault current in the event of overload or short-circuit fault.

[0034] Arc extinguishing component 211: The choice between a vacuum arc extinguishing component and an air arc extinguishing component depends on the application scenario of the fast transfer switch. For example, a vacuum arc extinguishing component is selected for harsh environments such as coal mines, rail transit, or chemical plants. An air arc extinguishing component is selected for environmentally friendly scenarios such as data centers, hospitals, and general enterprises.

[0035] like Figure 3 As shown, when the arc extinguishing component 211 is a vacuum arc extinguishing component, the vacuum arc extinguishing component includes: a vacuum housing, a vacuum stationary conductive rod 2111, a vacuum stationary contact 2112, a vacuum moving contact 2113, and a vacuum moving conductive rod 2114.

[0036] Specifically, the vacuum stationary contact 2112 is connected to the vacuum stationary conductive rod 2111 and is disposed within the vacuum arc extinguishing assembly housing 2110 via the vacuum stationary conductive rod 2111; the vacuum moving contact 2113 is located within the vacuum arc extinguishing assembly housing 2110 and is disposed opposite to the vacuum stationary contact 2112; one end of the vacuum moving conductive rod 2114 is connected to the vacuum moving contact 2113 and forms a movable sealed connection with the vacuum arc extinguishing assembly housing 2110 via the metal bellows 2115 within the vacuum arc extinguishing assembly housing 2110, and the other end is connected to the residual magnetism magnetic control mechanism 212 for transmission.

[0037] When the mechanical current-carrying branch 21 is opened or closed, the residual magnet type magnetic control mechanism 212 is activated, driving the vacuum moving conductive rod 2114 and the vacuum moving contact 2113 to move linearly, so that the vacuum moving contact 2113 is separated from or in contact with the vacuum stationary contact 2112.

[0038] like Figure 4 As shown, when the arc extinguishing component 211 is an air arc extinguishing component, the air arc extinguishing component includes: an air arc extinguishing component housing, an air-moving contact 2116, an air-moving conductive rod 2117, an air-stationary contact 2118, and multiple metal arc extinguishing grid plates 2119.

[0039] Specifically, the housing contains an arc-extinguishing grid support assembly, a rotatable moving contact arm, and an exhaust channel; an air-driven contact 2116 is located at the rotating end of the moving contact arm; one end of an air-driven conductive rod 2117 is connected to the fixed end of the moving contact arm, and the other end passes through the housing of the air arc-extinguishing assembly and is connected to the residual magnetism magnetic control mechanism 212; an air-driven stationary contact 2118 is fixedly installed inside the housing of the air arc-extinguishing assembly and is positioned opposite to the air-driven contact 2116; multiple metal arc-extinguishing grid plates 2119 are mounted on the arc-extinguishing grid support assembly and form arc-extinguishing grid inlets with openings facing the contact area above the air-driven stationary contact 2118 and the air-driven contact 2116.

[0040] When the mechanical current-carrying branch 21 is opened or closed, the residual magnetism control mechanism 212 drives the air-moving contact 2116 to move, so as to realize the contact or opening of the air-moving contact 2116 and the air-stationary contact 2118. An electric arc is generated at the moment the contact is opened. Under the action of electromagnetic force and airflow, the electric arc enters the area of ​​the metal arc-extinguishing grid plate 2119 through the arc-extinguishing grid inlet, is stretched, divided and cooled, and the high-temperature electric arc medium is discharged through the exhaust channel, thereby realizing air arc extinguishing.

[0041] like Figure 2 As shown, the residual magnetism type magnetic control mechanism 212 includes: an insulating pull rod 2121, a contact spring 2122, a tripping spring 2123, a bracket 2124, a static magnetic core 2125, a pressure strain gauge 2126, two tripping and closing coils 2127, a moving magnetic core 2128, and a limit block 2129.

[0042] Specifically, one end of the insulating pull rod 2121 is connected to the arc extinguishing component 211; the contact spring 2122 is sleeved on the insulating pull rod 2121 and is used to provide contact pressure during the closing process of the first source-side switch assembly 20 or the second source-side switch assembly 50; the opening spring 2123 is sleeved outside the contact spring 2122 and is used to provide opening driving force during the opening process of the first source-side switch assembly 20 or the second source-side switch assembly 50.

[0043] The bracket 2124 internally houses a stationary magnetic core 2125 and a moving magnetic core 2128, which are arranged opposite to each other to form a remanent magnetization-retaining magnetic circuit. The stationary magnetic core 2125 has three spaced-apart semi-grooves, and the moving magnetic core 2128 also has three spaced-apart semi-grooves. These three semi-grooves together form two side grooves and a central groove. In this embodiment of the invention, both the moving magnetic core 2128 and the stationary magnetic core 2125 are made of semi-hard magnetic material.

[0044] A pressure strain gauge 2126 is disposed at the bottom of the moving magnetic core 2128 to detect the contact pressure generated when the contact spring 2122 is pressed downward; two opening and closing coils 2127 are respectively disposed in the two side grooves to receive the opening pulse or closing pulse generated by the control module 30, and drive the moving magnetic core 2128 to move through the opening pulse and closing pulse; a limit block 2129 is disposed at the bottom of the moving magnetic core 2128 and is fixedly connected to the other end of the insulating pull rod 2121 to limit the movement stroke of the moving magnetic core 2128.

[0045] When the circuit breaker is opened, the opening and closing coil 2127 receives the opening drive pulse and generates electromagnetic force, breaking the residual magnetism holding effect between the moving magnetic core 2128 and the stationary magnetic core 2125. The opening spring 2123, which is in the energy storage state, releases its elastic force to drive the moving magnetic core 2128 to move in the opening direction. The moving magnetic core 2128 drives the insulating rod 2121 to move, which in turn drives the arc extinguishing component 211 to complete the opening. The contact spring 2122 releases its compression as the moving magnetic core 2128 moves, and the contact pressure collected by the pressure strain gauge 2126 decreases accordingly. The limit block 2129 moves with the moving magnetic core 2128 and restricts the moving magnetic core 2128 from moving further after reaching the limit position. The stationary magnetic core 2125 and the bracket 2124 remain fixed and stationary.

[0046] When the circuit is closed, the closing / opening coil 2127 receives the closing pulse and generates electromagnetic attraction, driving the moving magnetic core 2128 to move towards the stationary magnetic core 2125; the moving magnetic core 2128 drives the insulating pull rod 2121 to move, driving the arc extinguishing assembly 211 to complete the contact closure; the opening spring 2123 is compressed and re-stores energy; the contact spring 2122 is compressed to establish contact pressure, and the pressure strain gauge 2126 detects the contact pressure; the limit block 2129 restricts the travel in the closing direction; after the moving magnetic core 2128 and the stationary magnetic core 2125 are in contact, the closing position is maintained through the residual magnetic circuit; the stationary magnetic core 2125 is fixed to the bracket 2124.

[0047] (2-2) like Figure 2 As shown, the power electronic transient branch 22 is connected in parallel with the mechanical current-carrying branch 21 and is used to conduct briefly during normal opening and closing or source switching to cooperate with the mechanical current-carrying branch 21 to complete the current transfer.

[0048] Specifically, the power electronic transient branch 22 includes: at least one set of bidirectional controllable power switching units, each bidirectional controllable power switching unit including two IGBT power devices 221 arranged in reverse series or a bidirectional switching bridge composed of multiple IGBT power devices 221; the IGBT power devices 221 are provided with a surface-mount temperature sensor 222, which is located at the conductive connection part of the IGBT power devices 221, the control module 30 or the power electronic transient branch 22, and is used to detect the temperature status of the power electronic transient branch 22.

[0049] (2-3) like Figure 2 As shown, the absorption branch 23 is connected in parallel with the mechanical current-carrying branch 21 and / or the power electronic transient branch 22 to suppress transient overvoltages during the opening and closing of the circuit and the current transfer process.

[0050] Specifically, the absorption branch 23 includes at least an RC absorption circuit and a varistor MOV, which are used to limit the voltage rise rate and overvoltage peak during the turn-off process of the power electronic transient branch 22, thereby improving the turn-off reliability of the power electronic transient branch 22. (3) The control module 30 is connected to the first source-side switch assembly 20, the second source-side switch assembly 50, and the three-phase AC bus, respectively. It is configured to determine the current operating condition based on the status data of the first source input terminal 10, the second source input terminal 20, and the three-phase AC bus, and to control the interlocking action of the first source-side switch assembly 20 and the second source-side switch assembly 50 according to the current operating condition, as well as to control the mechanical current-carrying branch 21, the power electronic transient branch 22, and the absorption branch 23 to open or close.

[0052] Specifically, such as Figure 5 As shown, the control module 30 includes: a control unit 300, an IGBT temperature detection unit 301, an IGBT drive unit 302, a coil drive unit 303, a holding force detection unit 304, a current detection unit 305, a voltage detection unit 306, a vacuum detection unit 307, and a power supply unit 308.

[0053] The control unit 300 is used to control the IGBT temperature detection unit, IGBT drive unit 302, coil drive unit 303, holding force detection unit 304, current detection unit 305, voltage detection unit 306, power supply unit 308 and vacuum detection unit 307 to collect corresponding data.

[0054] The IGBT temperature detection unit 301 is electrically connected to the surface-mount temperature sensor 222 in the power electronic transient branch 22, and can acquire the temperature signal of the IGBT power device in the power electronic transient branch 22. The IGBT drive unit 302 is connected to the power electronic transient branch 22 and is used to drive or block the IGBT power device 221 according to the control command of the control unit 300. The coil drive unit 303 is connected to the opening and closing coil 2127 and is used to output the closing drive pulse or opening drive pulse to the opening and closing coil 2127 according to the control command of the control unit. The holding force detection unit 304 is connected to the pressure strain gauge 2126 and is used to acquire the contact pressure or residual magnetic holding force status signal. The current detection unit 305 is connected to the Rogowski coil 309 set on the first source input terminal 10, the second source input terminal 40, the three-phase AC bus or the sensitive load side circuit, and is used to acquire the main circuit current, load current and branch current, and obtain the current amplitude, current change rate and current zero crossing time information. The voltage detection unit 306 is connected to the first source input terminal 10, the second source input terminal 40 and the three-phase AC bus respectively, and is used to collect the three-phase voltage signals of the first source, the second source and the three-phase AC bus, and obtain voltage amplitude, frequency, phase sequence, zero crossing time and phase angle information.

[0055] When the arc extinguishing component 211 is a vacuum arc extinguishing component, the vacuum degree detection unit 307 is used to determine its vacuum state based on the withstand voltage, discharge or leakage current characteristics of the vacuum arc extinguishing component.

[0056] The power supply unit 308 is connected to the three-phase AC line of the control unit, the first source input terminal 10 and / or the second source input terminal 40, and is used to supply power to the control unit, the IGBT drive unit 302, the coil drive unit 303, the IGBT temperature detection unit 301, the holding force detection unit 304, the vacuum detection unit 307, the current detection unit 305 and the voltage detection unit 306.

[0057] The following example illustrates a hybrid transfer switch for switching between power sources in a photovoltaic-storage microgrid: like Figure 6 As shown, in practical applications, the first source input terminal 10 is connected to the low-voltage AC power grid, the second source input terminal 40 is connected to the energy storage AC output terminal consisting of an energy storage battery and an inverter, and the sensitive load 60 is connected to the three-phase AC bus.

[0058] First: Faulty operating conditions.

[0059] Power supply unit 308 maintains power supply to the entire unit, and voltage detection unit 306 collects voltage signals from various circuits. Current detection unit 305, in conjunction with Rogowski coil 309, collects current signals. IGBT temperature detection unit 301 collects IGBT device temperature and outputs an over-temperature fault signal. Vacuum detection unit 307 monitors the vacuum arc-extinguishing assembly and outputs an abnormal signal when the vacuum deteriorates. Holding force detection unit 304 collects contact pressure and residual magnetic holding force signals to help determine whether there is an abnormal contact tripping fault. Control unit 300 summarizes the detection signals from each unit to confirm whether the first source input terminal 10 and / or the second source input terminal 40, the three-phase AC bus, the sensitive load 60, the first source side switch group 20, or the second source side switch assembly 50 is faulty (overload, short circuit fault, or device malfunction).

[0060] If the control unit 300 confirms a fault or abnormality, it issues a blocking command to the IGBT drive unit 302 to block the power electronic transient branch 22; at the same time, it outputs a tripping pulse to the coil drive unit 303. After receiving the tripping drive pulse, the tripping and closing coil 2127 generates electromagnetic force, which drives the moving magnetic core 2128 to move in the tripping direction. The insulating pull rod 2121 follows the moving magnetic core 2128 to perform the fault tripping protection action.

[0061] Second: Inter-source switching operation.

[0062] The voltage detection unit 306, current detection unit 305, and IGBT temperature detection unit 301 collect their respective data in real time. When the control unit 300 confirms that there is no fault, it determines whether the low-voltage AC power grid needs inter-source switching based on the data collected by the above units. That is, when the first source-side switching component 20 has a voltage dip, short-term interruption, phase loss, or frequency abnormality, inter-source switching needs to be performed.

[0063] The control unit 300 identifies the first input source 10 terminal corresponding to the low-voltage AC grid as the source to be disconnected and the second input source terminal 40 corresponding to the energy storage AC output terminal as the source to be connected. Simultaneously, it determines the target opening phase of the source to be disconnected and the target closing phase of the source to be connected. Control commands are then sent to the IGBT drive unit 302 and the coil drive unit 303. The IGBT drive unit 302, according to the commands, turns on the IGBT power devices 221 of the corresponding phases of the source to be disconnected and the source to be connected (i.e., turns on the power electronic transient branch 22), realizing current transfer, and turns off after the turn-off conditions are met.

[0064] According to the control command, the coil drive unit 303 first outputs a tripping drive pulse to the tripping and closing coil 2127 of the source to be cut off. After receiving the tripping drive pulse, the tripping and closing coil 2127 breaks the residual magnetism holding effect between the moving magnetic core 2128 and the stationary magnetic core 2125. The tripping spring 2123 releases its elastic force to drive the moving magnetic core 2128 to move in the tripping direction. The insulating pull rod 2121 moves accordingly, thereby driving the arc extinguishing component 211 to complete the tripping. The contact spring 2122 releases its compression as the moving magnetic core 2128 moves, and the contact pressure collected by the pressure strain gauge 2126 decreases accordingly. The limit block 2129 moves with the moving magnetic core 2128.

[0065] Then, the coil drive unit 303 outputs a closing drive pulse to the source to be connected. The moving magnetic core 2128 of the source to be connected drives the insulating pull rod 2121 to move and complete the contact closure. The opening spring 2123 is compressed and re-stores energy. The contact spring 2122 generates contact pressure, and the pressure strain gauge 2126 detects the contact pressure. The limit block 2129 limits the travel in the closing direction. After the moving magnetic core 2128 and the stationary magnetic core 2125 are in contact, the closing position is maintained through the residual magnetic circuit.

[0066] The vacuum detection unit 307 maintains the vacuum status monitoring of the vacuum arc extinguishing assembly; the power supply unit 308 supplies power to all units.

[0067] When the control unit 300 confirms that it does not need to perform source switching, it continues to receive three-phase voltage signals and three-phase current signals in real time.

[0068] Third: Steady-state operating conditions.

[0069] When the control unit 300 confirms that the low-voltage AC power grid is supplying power normally, it enters the steady-state operation condition. The first source-side switch assembly 20 is in the closed and current-carrying state, the sensitive load 60 is supplied by the low-voltage AC power grid, and the second source-side switch assembly 50 is in the open or ready-to-connect state.

[0070] At this time, the power supply unit 308 continuously draws power from the first source input terminal 10 and / or the second source input terminal 40 to provide operating power to all units inside the control module 30. The voltage detection unit 306 continuously collects the three-phase voltage signals from the first source input terminal 10, the second source input terminal 40, and the three-phase AC bus, and outputs the voltage amplitude, frequency, phase sequence, zero-crossing time, and phase angle to realize real-time monitoring of the voltage status of each power supply. The current detection unit 305, in conjunction with the Rogowski coil 309, continuously collects the loop current from the first source input terminal 10, the second source input terminal 40, and the three-phase AC bus, and outputs the current amplitude, current change rate, and current zero-crossing time to monitor the main circuit, load, and branch current. The IGBT temperature detection unit 301 collects the temperature signal of the IGBT power device 221 inside the power electronic transient branch 22 in real time to complete the device temperature monitoring. The IGBT drive unit 302 maintains the blocking of the IGBT power device 221, and the power electronic transient branch 22 remains in the off state.

[0071] The coil drive unit 303 does not output drive pulses, the opening and closing coils 2127 do not operate, and the residual magnetism-type magnetic control mechanism 212 maintains the current opening or closing position by relying on residual magnetism. The holding force detection unit 304 continuously collects the signal output by the pressure strain gauge 2126 to obtain the contact pressure or residual magnetism holding force status in real time and monitor the contact closing and clamping condition. The vacuum detection unit 307 continuously monitors the vacuum status of the vacuum arc extinguishing assembly. The control unit 300 receives all status signals uploaded by the above detection units, completes the overall machine operation status monitoring, and does not perform source-to-source conversion related operations.

[0072] Example 2: Based on the same inventive concept, this embodiment of the invention also provides a control method for a hybrid transfer switch for switching between sources in a photovoltaic-storage microgrid, which is applied to a hybrid transfer switch for switching between sources in a photovoltaic-storage microgrid in Embodiment 1.

[0073] This method is as follows Figure 7 As shown, it includes: S1: Control module 30 acquires the three-phase voltage signal and three-phase current signal corresponding to the first source input terminal 10, the second source input terminal 40 and the three-phase AC bus respectively; S2: The control module 30 determines whether the photovoltaic-storage microgrid is in a fault operation condition based on the three-phase voltage signal and the three-phase current signal. S3: If the photovoltaic-storage microgrid is in a fault operation condition, the control module 30 blocks the power electronic transient branch 22 and controls the mechanical current-carrying branch 21 on the operation side to interrupt the fault current. S4: If the photovoltaic-storage microgrid is not in a fault operation condition, the control module 30 determines whether it is in an inter-source switching condition, and generates an interlock signal when it is in an inter-source switching condition, and controls the mechanical current-carrying branch 21 of the first source-side switching component 20 or the second source-side switching component 50 to perform opening and closing actions, the power electronic transient branch 22 to conduct for a short time, the control absorption branch 23 to suppress transient overvoltage, and the control to conduct the mechanical current-carrying branch 21. S5: When the source-to-source switching is completed and the system enters steady-state operation, the mechanical current-carrying branch 21 of the first source-side switching assembly 20 or the second source-side switching assembly 50 on the control operation side is turned on.

[0074] Specifically, the control module 30 first acquires the three-phase voltage signal, three-phase current signal, bus current, source-side current, IGBT temperature, contact pressure or holding force, vacuum state, and coil drive state of the first source input terminal 10, the second source input terminal 40, and the three-phase AC bus.

[0075] When the three-phase AC bus current exceeds the instantaneous protection threshold and the current change rate exceeds the preset change rate threshold, or when the three-phase AC bus current is detected to exceed the short-circuit protection threshold and the bus voltage is lower than the preset voltage threshold, the control module 30 determines that a short-circuit fault exists.

[0076] When the temperature of the IGBT power device 221 is detected to be higher than the preset temperature threshold, the contact pressure or residual magnetism holding force is lower than the preset threshold, the vacuum state of the vacuum interrupter is abnormal, the drive current of the opening and closing coil 2127 is abnormal, or the mechanical contact fails to reach the target position within a preset time, the control module 30 determines that there is a device malfunction. At this time, the control module 30 immediately blocks the power electronic transient branch 22 of the first source-side switch assembly 20 or the second source-side switch assembly 50 on the operating side and prohibits the backup source from being put into operation. At the same time, it drives the mechanical current-carrying branch 21 corresponding to the current source to open through the coil drive unit 303, and the fault current is interrupted by the arc extinguishing component 211. Then, it outputs a blocking alarm signal and waits for reset.

[0077] If there is no overload, short circuit, or device malfunction, the control module 30 further determines whether an inter-source switching needs to be performed. If no inter-source switching command is received, the current current-carrying state is maintained and monitoring continues. If an inter-source switching command is received, the control module 30 calculates the voltage amplitude, frequency, phase sequence, phase angle, and current zero-crossing time. Based on the inter-source switching command, the first source state, the second source state, the three-phase AC bus state, the voltage phase relationship, the current zero-crossing time, and the predicted action delay of the residual magnetism control mechanism 211, the control module 30 determines the source to be disconnected, the source to be connected, the target opening phase, and the target closing phase.

[0078] During the process of removing the source to be removed, the control module 30 first controls the power electronic transient branch 22 of the phase corresponding to the source to be removed to be turned on through the IGBT drive unit 302, so that the power electronic transient branch 22 has transient current carrying and commutation capabilities; then, it drives the opening and closing coil 2127 of the phase corresponding to the source to be removed through the coil drive unit 303, so that the mechanical current-carrying branch 21 of the corresponding phase is opened. When the control module 30 determines that the current of the mechanical current-carrying branch 21 has been transferred to the power electronic transient branch 22 according to the detection result of the current detection unit 305, and determines that the contact has reached the effective opening distance according to the mechanical contact state, the power electronic transient branch 22 of the phase corresponding to the source to be removed is turned off when the current crosses zero or the preset safety turn-off condition is met, thereby completing the removal of the source to be removed.

[0079] During the connection process of the source to be connected, the control module 30 outputs a closing control command in advance according to the target closing phase. First, the IGBT drive unit 302 controls the power electronic transient branch 22 of the corresponding phase of the source to be connected to conduct, forming a transient soft connection channel. Then, the coil drive unit 303 drives the opening and closing coils 2127 of the corresponding phase of the source to be connected, so that the mechanical current-carrying branch 21 of the corresponding phase closes according to the target closing phase. When the holding force detection unit 304 detects that the contact pressure or residual magnetic holding force reaches the preset threshold, and the current detection unit 305 detects that the current has been transferred from the power electronic transient branch 22 to the mechanical current-carrying branch 21, the control module 30 turns off the power electronic transient branch 22 of the source to be connected, so that the long-term current after connection is borne by the mechanical current-carrying branch 21. At this point, the rapid conversion between sources is completed, and the device enters a steady-state operation state.

[0080] During steady-state operation, the mechanical current-carrying branch 21 carries the main circuit current, while the power electronic transient branch 22 remains off, thereby reducing the long-term conduction loss and heat dissipation pressure of the IGBT power device 221. The control module 30 continuously monitors the status of the first source, the second source, the three-phase AC bus, and the sensitive load 60, and determines whether the device is operating abnormally based on information such as IGBT temperature, contact pressure or holding force, vacuum status, and coil drive status. When the temperature of the IGBT power device 221 is higher than the preset threshold, the contact pressure or residual magnetism holding force is lower than the preset threshold, the vacuum status of the vacuum arc-extinguishing component is abnormal, the drive current of the opening and closing coil 2127 is abnormal, or the mechanical contact fails to reach the target position within a preset time, the control module 30 executes a lockout alarm and prohibits re-closing or source switching.

[0081] Based on the above embodiments, through the above structure and control method, the present invention utilizes the short-term conduction of the power electronic transient branch 22 during normal switching to reduce switching impact and contact erosion. During steady-state operation, the mechanical current-carrying branch 21 undertakes long-term current carrying to reduce losses. In the event of overload or short-circuit fault, the power electronic transient branch 22 is blocked and the fault current is interrupted by the mechanical current-carrying branch 21, thereby taking into account rapid inter-source switching, low-loss operation, fault-safe interruption, and comprehensive online status monitoring.

[0082] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0083] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A hybrid transfer switch for switching between photovoltaic and energy storage microgrid sources, characterized in that, It includes a first source input terminal (10), a first source-side switch assembly (20), a second source input terminal (40), a second source-side switch assembly (50), and a control module (30); The first source-side switch assembly (20) is connected between the first source input terminal (10) and the three-phase AC bus, and is used to connect or disconnect the path between the first source input terminal (10) located in the low-voltage AC power supply and the grid load; The second source-side switch assembly (50) is connected between the second source input terminal (40) and the three-phase AC bus, and is used to connect or disconnect the path between the second source input terminal (40) in the low-voltage AC power supply and the grid load; The first source-side switch assembly (20) and the second source-side switch assembly (50) are provided with a mechanical current-carrying branch (21), a power electronic transient branch (22) and an absorption branch (23) connected in parallel. The control module (30), connected to the first source-side switch assembly (20), the second source-side switch assembly (50), and the three-phase AC bus, is configured as follows: Determine whether the photovoltaic-storage microgrid is in fault operation condition based on the three-phase voltage signal and the three-phase current signal; If the system is in a fault operation condition, the power electronic transient branch (22) of the first source-side switch assembly (20) and the second source-side switch assembly (50) is blocked, and the mechanical current-carrying branch (21) is controlled to interrupt the fault current. If not in fault operation condition, determine whether in source switching condition, and generate interlock signal when in source switching condition, and control the mechanical current-carrying branch (21) of the first source-side switch assembly (20) or the second source-side switch assembly (50) to perform opening and closing actions, short-term conduction of power electronic transient branch (22), and control the absorption branch (23) to suppress transient overvoltage; the interlock signal is used to control the first source-side switch assembly (20) and the second source-side switch assembly (50) to interlock; When the source-to-source switching is completed and the system enters a steady-state operating condition, the mechanical current-passing branch (21) of the first source-side switching assembly (20) or the second source-side switching assembly (50) on the control operating side is turned on.

2. The hybrid transfer switch for switching between photovoltaic and energy storage microgrid sources as described in claim 1, characterized in that, The mechanical flow branch (21) includes: Arc extinguishing assembly (211) is used to extinguish or cut off an electric arc; The residual magnet type magnetic control mechanism (212), which is connected to the arc extinguishing component (211) in a transmission manner, includes an insulating pull rod (2121), a contact spring (2122), a tripping spring (2123), a bracket (2124), a static magnetic core (2125), a pressure strain gauge (2126), two tripping and closing coils (2127), a moving magnetic core (2128), and a limit block (2129). The insulating pull rod (2121) is connected at one end to the arc extinguishing component (211) in a transmission manner; The contact spring (2122) is sleeved on the insulating pull rod (2121) and is used to generate contact pressure when the first source-side switch assembly (20) or the second source-side switch assembly (50) is in the closing process; The tripping spring (2123) is sleeved outside the contact spring (2122) and is used to provide tripping driving force when the first source-side switch assembly (20) or the second source-side switch assembly (50) is in the tripping process; The bracket (2124) has a stationary magnetic core (2125) and a moving magnetic core (2128) arranged opposite to each other. The stationary magnetic core (2125) and the moving magnetic core (2128) are provided with two side grooves and a central groove for placing the contact spring (2122) and the opening spring (2123). The bracket (2124) is slidably connected to the insulating pull rod (2121) through the contact spring (2122) and the opening spring (2123). The pressure strain gauge (2126) is disposed at the bottom of the moving magnetic core (2128) and is used to detect the contact pressure generated when the contact spring (2122) and the opening spring (2123) are pressed downward; The two opening and closing coils (2127) are respectively disposed in the two side grooves for receiving opening and closing pulses and driving the moving magnetic core (2128) to move; The limiting block (2129) is disposed at the bottom of the moving magnetic core (2128). The insulating pull rod (2121) passes through the contact spring (2122) and the opening spring (2123) and is fixedly connected to the moving magnetic core (2128) and the limiting block (2129) to limit the movement stroke of the moving magnetic core (2128).

3. The hybrid transfer switch for switching between photovoltaic and energy storage microgrid sources as described in claim 2, characterized in that, Both the static magnetic core (2125) and the moving magnetic core (2128) are semi-hard magnetic materials.

4. A hybrid transfer switch for switching between photovoltaic and energy storage microgrid sources as described in claim 2, characterized in that, When the arc-extinguishing assembly (211) is a vacuum arc-extinguishing assembly, the vacuum arc-extinguishing assembly includes: Vacuum arc extinguishing assembly housing (2110); The vacuum static conductive rod (2111) is fixedly connected to the housing (2110) of the vacuum arc extinguishing assembly; A vacuum stationary contact (2112) is disposed inside the housing (2110) of the vacuum arc extinguishing assembly; A vacuum moving contact (2113) is disposed inside the housing (2110) of the vacuum arc extinguishing assembly and is disposed opposite to the vacuum stationary contact (2112); The vacuum moving conductive rod (2114) is connected to the vacuum moving contact (2113), and forms a movable sealed connection with the vacuum arc extinguishing component housing (2110) through the metal bellows (2115) inside the vacuum arc extinguishing component housing, and is connected to the insulating pull rod (2121) in a transmission manner.

5. A hybrid transfer switch for switching between photovoltaic and energy storage microgrid sources as described in claim 2, characterized in that, When the arc-extinguishing component (211) is an air arc-extinguishing component, the air arc-extinguishing component includes: The air arc extinguishing assembly housing includes an arc extinguishing grid support assembly, a rotatable moving contact arm, and an exhaust channel; An air-operated contact (2116) is disposed at the rotating end of the movable contact arm; The air-powered conductive rod (2117) has one end connected to the fixed end of the moving contact arm, and the other end passes through the housing of the air arc extinguishing assembly and is connected to the insulating pull rod (2121); An air stationary contact (2118) is fixedly disposed on one side inside the housing of the air arc extinguishing assembly and is disposed opposite to the air moving contact (2116); Multiple metal arc-extinguishing grid plates (2119) are installed on the arc-extinguishing grid plate support assembly and form an arc-extinguishing grid inlet with an opening facing the contact area above the air stationary contact (2118) and the air moving contact (2116); the exhaust channel is connected to the upper part of the metal arc-extinguishing grid plates (2119) and is used to discharge the high-temperature gas generated during the breaking process.

6. A hybrid transfer switch for switching between photovoltaic and energy storage microgrid sources as described in claim 1, characterized in that, The power electronic transient branch (22) includes a bidirectional controllable power switching unit composed of at least two IGBT power devices (221), wherein the IGBT power devices (221) include: A surface-mount temperature sensor (222) is electrically connected to the control module (30).

7. A hybrid transfer switch for switching between photovoltaic and energy storage microgrid sources as described in claim 4, characterized in that, The control module (30) includes: The IGBT temperature detection unit (301) is connected to the power electronic transient branch (22) and is used to collect the temperature signal in the power electronic transient branch (22); IGBT drive unit (302) is connected to the power electronic transient branch (22) and is used to drive or block the IGBT power device (221). A coil driving unit (303) is connected to the opening and closing coil (2127) and is used to output opening and closing driving pulses to drive the opening and closing coil (2127); The holding force detection unit (304) is connected to the pressure strain gauge (2126) and is used to collect contact pressure or residual magnetism holding force status signals; The current detection unit (305) is connected to the first source input terminal (10), the second source input terminal (40) and the three-phase AC bus, and is used to collect the current signals corresponding to the first source input terminal (10), the second source input terminal (40) and the three-phase AC bus; The voltage detection unit (306) is connected to the first source input terminal (10), the second source input terminal (40) and the three-phase AC bus, and is used to collect the three-phase voltage signals of the first source input terminal (10), the second source input terminal (40) and the three-phase AC bus; A vacuum detection unit (307) is electrically connected to the arc extinguishing component (211) and is used to determine the vacuum state of the arc extinguishing component (211) when the arc extinguishing component (211) is a vacuum arc extinguishing component. The control unit (300) is electrically connected to the IGBT temperature detection unit (301), IGBT drive unit (302), coil drive unit (303), holding force detection unit (304), current detection unit (305), voltage detection unit (306) and vacuum detection unit (307), and receives the acquired signals; The power supply unit (308) is connected to the three-phase AC bus of the control unit (300), the first source input terminal (10) and the second source input terminal (40), and is used to supply power to the control unit (300), the IGBT temperature detection unit (301), the IGBT drive unit (302), the coil drive unit (303), the holding force detection unit (304), the current detection unit (305), the voltage detection unit (306) and the vacuum detection unit (307).

8. A control method for a hybrid transfer switch for switching between photovoltaic and energy storage microgrid sources, characterized in that, The hybrid transfer switch for switching between photovoltaic and energy storage microgrid sources as described in any one of claims 1-7 includes the following steps: S1: The control module (30) acquires the three-phase voltage signal and three-phase current signal corresponding to the first source input terminal (10), the second source input terminal (40) and the three-phase AC bus respectively; S2: The control module (30) determines whether the photovoltaic-storage microgrid is in a fault operation condition based on the three-phase voltage signal and the three-phase current signal; S3: If the photovoltaic-storage microgrid is in a fault operation condition, the control module (30) blocks the power electronic transient branch (22) and controls the mechanical current-carrying branch (21) on the operating side to interrupt the fault current; S4: If the photovoltaic-storage microgrid is not in a fault operation condition, the control module (30) determines whether it is in an inter-source switching condition, and generates an interlock signal when it is in an inter-source switching condition, and controls the mechanical current-carrying branch (21) of the first source-side switch assembly (20) or the second source-side switch assembly (50) to perform opening and closing actions, short-term conduction of the power electronic transient branch (22), control the absorption branch (23) to suppress transient overvoltage, and control the mechanical current-carrying branch (21) to conduct; S5: When the source switching is completed and the steady-state operation is entered, control the first source-side switching component (20) or the second source-side switching component (50) on the operating side.

9. The control method for a hybrid transfer switch for switching between photovoltaic and energy storage microgrid sources as described in claim 8, characterized in that, Step S4 includes: When in the inter-source switching condition, the control module (30) controls the power electronic transient branch (22) of the source to be cut off to be short-term turned on, controls the mechanical current-carrying branch (21) to perform the opening action in the target opening phase, and controls the absorption branch (23) to suppress transient overvoltage and determines whether the first safety turn-off constraint condition is met. Determine whether the current is transferred to the power electronic transient branch (22) and whether the contact movement distance of the arc extinguishing component of the mechanical current-carrying branch is not less than the effective distance; If the current is transferred to the power electronic transient branch (22) and the contact movement distance is not less than the effective distance, then determine whether the current has crossed zero or whether the first safety turn-off condition is met. If the current crosses zero or meets the first safety shutdown condition, the control module (30) controls the power electronic transient branch (22) of the first source-side switch assembly or the second source-side switch assembly (50) of the source to be connected to conduct for a short time, controls the mechanical current-carrying branch (21) to perform the closing action at the target closing phase, and controls the absorption branch (23) to suppress the transient overvoltage. Determine that the contact pressure of the arc-extinguishing component of the mechanical current-passing branch (21) is greater than the pressure threshold and that the current is transferred to the mechanical current-passing branch (21) of the first source-side component (20) or the second source-side switching component (50) of the source to be connected. If the contact pressure is greater than the pressure threshold, and the current is transferred to the mechanical current-carrying branch (21) of the first source-side component or the second source-side switching component (50) of the source to be connected, then the power electronic transient branch (22) of the source to be connected is turned off, and the steady-state operating condition is entered.

10. The control method for a hybrid transfer switch for switching between photovoltaic and energy storage microgrid sources as described in claim 9, characterized in that, The steps for determining the target closing phase and the target opening phase include: Obtain the zero-crossing time of the current of the source to be cut off and the preset opening delay of the mechanical current-carrying branch (21), and determine the target opening phase based on the zero-crossing time of the current and the preset opening delay; The voltage difference between the voltage of the source to be connected and the voltage on the receiving side is calculated in real time, and the target closing phase is determined based on the voltage difference, the voltage difference threshold and the preset closing delay.

Images