Zero-interruption dual-power-supply rapid switching device

Abstract

The utility model discloses a zero interruption dual power supply fast switching device, comprising a dual power supply switch, a power electronic assembly, an output switch QF and a load which are connected in sequence, the power electronic assembly comprises an electronic bypass unit VT, a mechanical bypass contactor KM, an isolation transformer TM, a bidirectional converter CU and a super capacitor energy storage unit CAP, a contact S1 in the dual-power switch is connected with a main power supply, a contact S2 is connected with a standby power supply, a mechanical bypass contactor KM is connected with an electronic bypass unit VT in parallel, an isolation transformer TM is connected to the output end of the electronic bypass unit VT, and the two ends of a bidirectional converter CU are connected with the isolation transformer TM and a super capacitor energy storage unit CAP respectively. According to the device, the dual-power-supply change-over switch is matched with the power electronic component, so that rapid switching of the dual-power-supply switch is realized, the problem of power supply interruption in the switching process is solved, and the reliability of power supply is improved; and meanwhile, few energy storage elements are used, and the cost is low.

Description

Technical Field

[0001] The utility model relates to the technical field of power quality, in particular to a zero-interruption dual-power supply fast switching device. Background Art

[0002] With economic development and social progress, the automation degree and production continuity of modern advanced manufacturing factories are getting higher and higher, and people's requirements for the safety and reliability of power equipment are also getting higher and higher. In this context, two or more truly completely independent power supplies are usually introduced in system design. In order to prevent the impact of power outages and improve power supply reliability, dual power supply switches have begun to be widely used in various power equipment for conversion between two power supplies. When there is a problem with the main power supply, it can be quickly switched to another backup power supply to ensure the continuous power supply of the power equipment. According to different switching principles, dual power supply switches can be divided into two types: PC level and CB level. Whether it is PC level or CB level, it is mainly a mechanical structure, and it takes a certain amount of time in the switching process of the entire mechanism. This time generally includes two sections. One is the delay time specially introduced in the controller, which is mainly introduced to avoid the delay caused by the interference from the high-voltage side of the power grid. It is set by the controller and is adjustable, generally in the range of 100ms-5s. The other section is the switching action time, which is the inherent action time of the mechanical switch (main body). It is related to the structure of the switch, generally in the range of 50ms-3s. This time cannot be adjusted. Therefore, the total action time of a dual power switching switch is generally not less than 150ms, or even longer, which means that the power grid will be interrupted for 7 cycles, and seamless switching without interruption cannot be achieved. How to quickly complete the switching without interruption is the direction that technicians in this field are committed to studying. Utility Model Content

[0003] The utility model aims to overcome the deficiencies of the prior art and provide a zero-interruption dual power supply fast switching device, which solves the problem of short-term power supply interruption during the conversion process of conventional PC-level or CB-level dual power supply automatic switching switches.

[0004] To achieve the above-mentioned purpose, the technical solution adopted by the utility model is: a zero-interruption dual power fast switching device, including a dual power switch, a power electronic component, an output switch QF and a load connected in sequence, the power electronic component includes an electronic bypass unit VT, a mechanical bypass contactor KM, an isolation transformer TM, a bidirectional converter CU, and a supercapacitor energy storage unit CAP, the contact S1 in the dual power switch is connected to the main power supply, the contact S2 is connected to the backup power supply, the mechanical bypass contactor KM is connected in parallel with the electronic bypass unit VT, the isolation transformer TM is connected to the output end of the electronic bypass unit VT, and the two ends of the bidirectional converter CU are respectively connected to the isolation transformer TM and the supercapacitor energy storage unit CAP.

[0005] As a specific implementation, the dual power switch is integrated with the power electronic component and the output switch QF, and the dual power switch serves as an incoming line switch of the device.

[0006] Due to the application of the above technical solution, the utility model has the following advantages compared with the prior art:

[0007] 1) The zero-interruption dual power fast switching device of the utility model adopts a dual power switch and a power electronic component. Through the hybrid design technology of the dual power switch and the power electronic component, the dual power switch is fast switched, the power supply interruption problem during the switching process is solved, and the power supply reliability is improved;

[0008] 2) The energy storage unit in the zero-interruption dual-power fast switching device of the utility model only provides energy for the load during the dual-power switch switching process, so there is no need to configure a large number of energy storage elements, thereby reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is a schematic diagram of the zero-interruption dual power supply fast switching device described in the utility model;

[0010] Figure 2 The zero-interruption dual-power fast switching device of the utility model is in the mode when the main power supply is working;

[0011] Figure 3 It is the mode of the zero-interruption dual-power fast switching device of the utility model when it is in the process of switching from the main power supply to the backup power supply;

[0012] Figure 4 The zero-interruption dual-power supply fast switching device of the utility model is in the mode when the backup power supply is working;

[0013] Figure 5 It is a timing diagram of the zero-interruption dual-power fast switching device of the utility model when the main power supply is switched to the backup power supply;

[0014] Among them: 1. Dual power switch; 2. Power electronic components; 3. Output switch QF. DETAILED DESCRIPTION

[0015] The following is combined with Figure 1-5 The technical solution of the utility model is further explained with reference to the accompanying drawings and specific embodiments.

[0016] The utility model provides a zero-interruption dual power fast switching device, comprising a dual power switch 1, a power electronic component 2, an output switch QF3 and a load connected in sequence, wherein the dual power switch is integrated with the power electronic component and the output switch QF.

[0017] Here, the dual power switch serves as the incoming line for the main power supply and the backup power supply; the power electronic component serves as the power supply unit for the load during the conversion process of the dual power switch; and the output switch QF is used to connect the load and provide load short-circuit protection.

[0018] Here, the dual power switch serves as the incoming switch of the device, including contacts S1 and S2, wherein contact S1 is connected to the main power supply and contact S2 is connected to the backup power supply.

[0019] Here, the power electronic components include an electronic bypass unit VT, a mechanical bypass contactor KM, an isolation transformer TM, a bidirectional converter CU, and a supercapacitor energy storage unit CAP.

[0020] Among them, the mechanical bypass contactor KM is mainly used to automatically enter the bypass state when the electronic bypass fails, ensuring that the subsequent load is powered on and is in the disconnected state during normal operation.

[0021] The electronic bypass unit VT uses two thyristors in anti-parallel connection, which is mainly used to quickly cut off the main circuit and switch to the power electronic component part to ensure the power supply of the subsequent stage.

[0022] Isolation transformer TM is mainly used for isolating the output of the converter to ensure the safety of system operation.

[0023] The bidirectional converter CU includes two working states: rectification and inversion. When working in the rectification state, the power grid charges the supercapacitor through the isolation transformer and the bidirectional converter; when working in the inversion state, the supercapacitor provides energy, which is converted by the bidirectional converter to supply power to the subsequent load.

[0024] The supercapacitor energy storage unit CAP is mainly used to store energy and is used for bidirectional converter inversion to supply power to subsequent loads.

[0025] Specifically, the mechanical bypass contactor KM is connected in parallel with the electronic bypass unit VT, the isolation transformer TM is connected to the output end of the electronic bypass unit VT, and the two ends of the bidirectional converter CU are respectively connected to the isolation transformer TM and the supercapacitor energy storage unit CAP.

[0026] The dual power fast switching device of the utility model also includes a controller for switching the dual power switch. When the power grid is normal, the main power supplies power to the load through the dual power switching switch, and at the same time charges the supercapacitor energy storage unit CAP through the bidirectional converter CU, but the supercapacitor energy storage unit CAP does not supply power to the load; when there is a problem with the main power supply, the controller sends a conversion instruction to the dual power switch, the dual power switch contacts separate, and the power electronic component will cut off the electronic bypass unit VT within 1ms, and supply power to the load through the supercapacitor energy storage unit CAP through the bidirectional converter CU and the isolation transformer TM until the dual power switch conversion is completed. When the conversion is completed, the power electronic component stops outputting, and the load is still powered by the conversion switch. Through the above working process, the power interruption problem in the dual power switch conversion process is solved, and the dual power switch is achieved. The effect of zero interruption and fast conversion meets the uninterrupted power supply requirements of the subsequent load.

[0027] Specifically, the dual power supply fast switching device has three working states:

[0028] 1) The main power supply is in normal state

[0029] When the main power supply is normal, the contact S1 in the dual power switch is in a closed state, the output circuit breaker QF is in a closed state, and the electronic bypass unit VT is in a conducting state. At this time, the load is supplied by the main power supply through the dual power switch contact S1, the electronic bypass unit VT, and the output switch QF to the subsequent load. At the same time, the main power supply charges the supercapacitor energy storage unit CAP through the isolation transformer TM and the bidirectional converter CU. At this time, the bidirectional converter is in a rectifying state, such as Figure 2 shown.

[0030] 2) The main power supply switches to the standby power supply state

[0031] When the controller in the switching device detects that the main power supply is abnormal and the main power supply needs to be switched to the backup power supply, the controller sends a switching command to the dual power switch. Due to the switching time of the dual power switch contacts S1 and S2, a power interruption will occur. At this time, the controller sends a cut-off command to the electronic bypass unit, cuts off the power electronic bypass unit VT, and supplies power to the subsequent load through the inverter output of the bidirectional converter CU until the dual power switch conversion is completed. At this time, the bidirectional converter works in the inverter state, and its energy is provided by the supercapacitor energy storage element CAP, such as Figure 3 The specific switching process is as follows: Figure 5 The time axis in the diagram starts from the abnormal voltage of the main power supply (at t1), and goes through the processes of voltage abnormality detection, separation of the mechanical contacts of the dual power switch, removal of the electronic bypass unit and the power electronic component functions, etc., until the dual power switch conversion is completed (at t5).

[0032] 3) Backup power supply working status

[0033] When the controller detects that the dual power switch has successfully converted the main power supply to the backup power supply, the power electronic components will exit operation, and the load is still powered by the dual power switch. At this time, the bidirectional converter CU works in the rectification state, charging the supercapacitor energy storage element CAP to store energy for the next conversion, such as Figure 4 shown.

[0034] By adopting the dual power fast switching device of the utility model, the dual power conversion switch is matched with the power electronic component to realize the fast switching of the dual power switch, solve the problem of power supply interruption during the switching process, and improve the reliability of power supply; because the device only needs to provide energy to the load during the switching process of the dual power switch, there is no need to configure a large number of energy storage elements, so the cost is relatively low.

[0035] The above embodiments are only for illustrating the technical concept and features of the utility model, and their purpose is to enable people familiar with the technology to understand the content of the utility model and implement it accordingly, and they cannot be used to limit the protection scope of the utility model. Any equivalent changes or modifications made according to the spirit of the utility model should be included in the protection scope of the utility model.

Claims

1. A zero-interruption dual power supply fast switching device, characterized in that: It includes a dual power switch, a power electronic component, an output switch QF and a load connected in sequence. The power electronic component includes an electronic bypass unit VT, a mechanical bypass contactor KM, an isolation transformer TM, a bidirectional converter CU, and a supercapacitor energy storage unit CAP. The contact S1 in the dual power switch is connected to the main power supply, and the contact S2 is connected to the backup power supply. The mechanical bypass contactor KM is connected in parallel with the electronic bypass unit VT. The isolation transformer TM is connected to the output end of the electronic bypass unit VT. The two ends of the bidirectional converter CU are respectively connected to the isolation transformer TM and the supercapacitor energy storage unit CAP.

2. A zero-interruption dual power supply fast switching device according to claim 1, characterized in that: The dual power switch is integrated with the power electronic component and the output switch QF, and the dual power switch serves as an incoming line switch of the device.

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