A power grid uninterruptible power supply automatic switching system, method and driving circuit

Abstract

This invention discloses an automatic switching system, method, and drive circuit for an uninterruptible power supply (UPS) in the field of power electronics. It includes a power module for providing electrical energy to the system; a relay switch unit for controlling the switching of mains power input; an accelerated turn-off unit for accelerating the turn-off of the relay switch unit; a circuit switching unit for switching a high-current drive circuit to a low-current drive circuit after a predetermined delay; and a control module for outputting a high-level signal to control the circuit switching unit to switch the high-current drive circuit to accelerate the closing of the relay switch unit, and outputting a low-level signal to control the accelerated turn-off unit to accelerate the turn-off of the relay switch unit. This invention employs a delayed switching drive design and an accelerated turn-off unit, which significantly simplifies the power supply hardware design, reduces the power requirements of the auxiliary power module, and significantly shortens the relay turn-off time, ensuring the stability and reliability of the UPS during the switching process.

Description

Technical Field

[0001] This invention relates to the field of power electronics technology, and in particular to an automatic switching system, method and driving circuit for uninterruptible power supplies in power grids. Background Technology

[0002] When the mains power fails, the energy storage inverter or uninterruptible power supply (UPS) needs to quickly switch to inverter mode to ensure uninterrupted power supply to the load. The most common challenge in this process is that the relay turn-off time at the mains input generally exceeds 10 milliseconds, severely impacting the stability of the load's power supply. To address this issue, existing technologies typically employ two methods: one is to use an additional SCR (silicon controlled rectifier) ​​circuit connected in parallel with the relay. While this method accelerates the switching transition, it results in complex drive circuitry, numerous components, higher costs, and an increased risk of failure. The other method is to use a dual-power supply strategy, switching to a low-voltage power supply after the relay closes. Although this reduces relay heat generation and the power supply burden on the auxiliary power source, it also incurs additional costs.

[0003] When a relay is driven by its rated voltage, the heat generated by the internal coil accelerates the aging of the insulation material, eventually leading to relay failure. Increased load on the auxiliary power supply is also common, which not only increases system design and cost but also affects system reliability. Therefore, existing technologies typically employ a dual-power supply design, using high voltage during the initial relay closure to ensure reliable opening and closing, and then switching to a low-voltage power supply to mitigate the damage caused by high voltage. However, this strategy remains a costly and complex design. Summary of the Invention

[0004] To address the aforementioned issues, this invention provides an automatic switching system, method, and drive circuit for uninterruptible power supplies (UPS) in power grids. By employing a delayed switching drive design and an accelerated shutdown unit, the system significantly simplifies power supply hardware design, reduces the power requirements of auxiliary power modules, and substantially shortens the relay shutdown time, thereby ensuring the stability and reliability of the UPS during the switching process.

[0005] The above objectives can be achieved through the following approach:

[0006] An automatic switching system for an uninterruptible power supply (UPS) includes a power supply module, a switching module, and a control module. The switching module includes a relay switch unit, an accelerated shutdown unit, and a circuit switching unit. The power supply module is electrically connected to both the accelerated shutdown unit and the circuit switching unit to provide power to the system. The relay switch unit is connected to both the accelerated shutdown unit and the circuit switching unit to control the on / off state of the mains power input. The accelerated shutdown unit is electrically connected to both the relay switch unit and the power supply module to accelerate the shutdown of the relay switch unit. The circuit switching unit is electrically connected to the power supply module, the accelerated shutdown unit, and the relay switch unit to switch a high-current drive circuit to a low-current drive circuit after a predetermined delay. The control module is electrically connected to the circuit switching unit and outputs a high-level signal to control the circuit switching unit to switch the high-current drive circuit, accelerating the closing of the relay switch unit. The control module is also electrically connected to the accelerated shutdown unit and outputs a low-level signal to control the accelerated shutdown unit to accelerate the shutdown of the relay switch unit.

[0007] Optionally, the circuit switching unit includes a loop control subunit and a loop switching subunit. The loop control subunit includes a resistor R1, a resistor R2, and a transistor Q1. One end of the resistor R1 is electrically connected to the control module, and the other end of the resistor R1 is electrically connected to the base of the transistor Q1 and one end of the resistor R2. The other end of the resistor R2 is electrically connected to the collector and ground terminal of the transistor Q1, and the emitter of the transistor Q1 is electrically connected to the loop switching subunit.

[0008] Optionally, the circuit switching subunit includes: a capacitor C1, a resistor R3, and a transistor Q2; wherein, one end of the capacitor C1 is electrically connected to the power module, the other end of the capacitor C1 is electrically connected to one end of the resistor R3, the other end of the resistor R3 is electrically connected to the collector of the transistor Q2, and the emitter of the transistor Q2 is electrically connected to the relay switch unit; the end of the resistor R3 that is not electrically connected to the capacitor C1 is electrically connected to the emitter of the transistor Q2, and the end of the resistor R3 that is electrically connected to the capacitor C1 is electrically connected to the base of the transistor Q2.

[0009] Optionally, the circuit switching subunit further includes a resistor R4; wherein one end of the resistor R4 is electrically connected to the collector of the transistor Q2, and the other end of the resistor R4 is electrically connected to the emitter of the transistor Q2.

[0010] Optionally, the accelerated shutdown unit includes a diode D1, a capacitor C2, a resistor R5, and a transistor Q3; wherein, the input terminal of the diode D1 is electrically connected to the power supply module, the output terminal of the diode D1 is electrically connected to one end of the capacitor C2, the other end of the capacitor C2 is electrically connected to one end of the resistor R5, and the other end of the resistor R5 is electrically connected to the ground terminal; the end of the capacitor C2 that is electrically connected to the diode D1 is electrically connected to the relay switch unit, the collector of the transistor Q3 is electrically connected to the power supply module, and the emitter of the transistor Q3 is electrically connected to the end of the capacitor C2 and the resistor R5 that are electrically connected.

[0011] Optionally, the accelerated shutdown unit further includes a resistor R6; wherein one end of the resistor R6 is electrically connected to the base of the transistor Q3, and the other end of the resistor R6 is electrically connected to the emitter of the transistor Q1.

[0012] Optionally, the relay switch unit includes: a relay switch K1; wherein one end of the relay switch K1 is electrically connected to the emitter of the transistor Q2, and the other end of the relay switch K1 is electrically connected to the capacitor C2.

[0013] Optionally, the relay switch unit further includes a diode D2; wherein the input terminal of the diode D2 is electrically connected to the emitter of the transistor Q2, and the output terminal of the diode D2 is electrically connected to the capacitor C2.

[0014] Based on the same inventive concept, the present invention also provides an automatic switching method for an uninterruptible power supply (UPS) in a power grid, applicable to any of the aforementioned UPS automatic switching systems. The method includes: controlling a switching unit via a high-level signal to switch to a high-current drive circuit, causing the relay switch K1 to close rapidly; after a predetermined delay, automatically switching the high-current drive circuit to a low-current drive circuit, keeping the relay switch K1 in a closed state; when it is necessary to turn off the relay switch K1, controlling an accelerated turn-off unit via a low-level signal to instantaneously pull the drive level of the relay switch K1 down to zero, thereby accelerating the turn-off time of the relay switch K1.

[0015] Based on the same inventive concept, the present invention also provides an automatic switching drive circuit for uninterruptible power supply in the power grid, the drive circuit including an automatic switching system for uninterruptible power supply as described in any of the foregoing descriptions.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] 1. This invention significantly shortens the relay turn-off time by integrating an accelerated turn-off circuit. When power switching is required, the control module outputs a high-level signal, which quickly switches to a high-current drive circuit through the circuit switching unit, causing the relay switch K1 to close rapidly. When the relay switch K1 needs to be turned off, the control module outputs a low-level signal, and the accelerated turn-off unit instantly pulls the drive level of the relay switch K1 down to zero, thereby achieving rapid turn-off. This design ensures stability and reliability in uninterruptible power supply applications.

[0018] 2. The circuit switching unit can use a large current to ensure reliable opening and closing in the initial stage of relay closure, and then automatically switch to a small current drive circuit. This not only keeps the relay switch K1 in the closed state, but also reduces current consumption, prevents the internal coil of the relay switch unit from overheating, extends the service life of the equipment, and reduces the power supply burden of the auxiliary power supply.

[0019] 3. The circuit structure used in this invention is simpler. By integrating an accelerated shutdown circuit design, the design of the power supply hardware is greatly simplified, reducing the power requirements of the auxiliary power module. This not only reduces the system cost but also improves the system reliability.

[0020] 4. Protective components such as diode D2 are added to the relay switch unit; when the emitter voltage of transistor Q2 rises instantaneously, diode D2 can quickly conduct, diverting excess current to capacitor C2, thereby protecting transistor Q2 from damage. This design enhances the stability and safety of the system.

[0021] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description, claims and drawings. Attached Figure Description

[0022] 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 some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the structure of an automatic switching system for uninterruptible power supply in a power grid according to an embodiment of the present invention.

[0024] Figure 2 This is a circuit diagram of an automatic switching system for uninterruptible power supplies in a power grid, according to an embodiment of the present invention.

[0025] Figure 3 This is a flowchart illustrating an automatic switching method for uninterruptible power supplies in a power grid according to an embodiment of the present invention. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, 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] Reference Figure 1 One embodiment of the present invention proposes an automatic switching system for uninterruptible power supplies in the power grid. It adopts a delayed switching drive design and an accelerated shutdown unit, which can greatly simplify the power supply hardware design, reduce the power requirements of the auxiliary power supply module, and significantly shorten the turn-off time of the relay, thereby ensuring the stability and reliability of the uninterruptible power supply in the switching process.

[0028] The system in this embodiment specifically includes: a power supply module, a switching module, and a control module. The switching module includes a relay switch unit, an accelerated shutdown unit, and a circuit switching unit; wherein...

[0029] The power module is electrically connected to the accelerated shutdown unit and the circuit switching unit, respectively, and is used to provide power to the system.

[0030] Specifically, such as Figure 2 As shown, the power module provides stable and reliable power to the entire system. The power module can be a high-performance DC power supply that can output sufficient current to drive the relay switch K1.

[0031] The relay switch unit is connected to the accelerated shutdown unit and the circuit switching unit respectively, and is used to control the on and off of the mains power input;

[0032] Specifically, the relay switch unit, as the main switching element, controls the on / off state of the mains input circuit.

[0033] The accelerated shutdown unit is electrically connected to the relay switch unit and the power module respectively, and is used to accelerate the shutdown of the relay switch unit.

[0034] Specifically, the accelerated shutdown unit accelerates the relay disconnection process under the action of a low-level signal; the accelerated shutdown unit can be a circuit composed of a fast-discharge diode and a capacitor, which can discharge quickly to accelerate the disconnection of the relay.

[0035] The circuit switching unit is electrically connected to the power module, the accelerated shutdown unit and the relay switch unit respectively, and is used to switch the high current drive circuit to a low current drive circuit after a predetermined delay time.

[0036] Specifically, after the relay switch unit is closed, the circuit switching unit switches to the low-current drive circuit after a predetermined delay. The circuit switching unit can be a circuit composed of a MOSFET and a resistor. By controlling the conduction and cutoff of the MOSFET, the switching of different current circuits can be achieved.

[0037] The control module is electrically connected to the circuit switching unit and is used to output a high-level signal to control the circuit switching unit to switch the high-current drive circuit and accelerate the closing of the relay switch unit; the control module is also electrically connected to the acceleration turn-off unit and is used to output a low-level signal to control the acceleration turn-off unit to accelerate the turn-off of the relay switch unit.

[0038] Specifically, the control module outputs high-level and low-level signals to control the circuit switching unit and the accelerated shutdown unit in the switching module, thereby enabling the relay switch unit to close quickly and disconnect reliably. The control module can be a microcontroller (MCU). When the relay switch unit needs to be closed, it outputs a high-level signal to control the circuit switching unit to switch to a high-current drive circuit, so that the relay switch unit receives a large current and closes quickly. When the relay switch unit needs to be disconnected, the control module outputs a low-level signal, so that the accelerated shutdown unit discharges quickly, accelerating the disconnection process of the relay switch unit.

[0039] For example, the control module detects a condition requiring the relay switch unit to close (such as an external signal trigger) and outputs a high-level signal; after receiving the high-level signal, the circuit switching unit switches to a high-current drive circuit; the high-current drive circuit provides sufficient current to the relay switch unit, causing it to close quickly; after a delay (such as a few milliseconds to a few seconds), the circuit switching unit automatically switches to a low-current drive circuit; the low-current drive circuit maintains the closed state of the relay switch unit while reducing the current to prevent the internal coil of the relay switch unit from overheating.

[0040] For example, the control module detects a condition requiring the relay switch unit to be disconnected (such as an external signal trigger) and outputs a low-level signal; after receiving the low-level signal, the accelerated shutdown unit discharges rapidly, accelerating the disconnection process of the relay switch unit; after the relay switch unit is disconnected, the circuit switching unit remains in a low-current drive circuit state, waiting for the next closing operation; through the above working principle, the rapid closing and reliable disconnection of the relay switch unit are achieved, while reducing the heating of the internal coil of the relay switch unit and the power supply burden of the power module, thus improving the stability and reliability of the system.

[0041] Furthermore, such as Figure 2As shown, the circuit switching unit includes a loop control subunit and a loop switching subunit. The loop control subunit includes resistor R1, resistor R2, and transistor Q1; wherein,

[0042] One end of resistor R1 is electrically connected to the control module, and the other end of resistor R1 is electrically connected to the base of transistor Q1 and one end of resistor R2. The other end of resistor R2 is electrically connected to the collector of transistor Q1 and the ground terminal. The emitter of transistor Q1 is electrically connected to the loop switching subunit.

[0043] Specifically, the loop control subunit mainly consists of resistors R1 and R2 and transistor Q1. Resistor R1 serves as a current limiter and voltage divider. One end of it is electrically connected to the control module to receive control signals from the control module. The other end of resistor R1 is electrically connected to both the base of transistor Q1 and one end of resistor R2. The other end of resistor R2 is electrically connected to the collector of transistor Q1 and the ground terminal, forming a basic common-emitter amplifier circuit.

[0044] For example, when the control module outputs a high-level signal, current flows through resistor R1 into the base of transistor Q1, causing transistor Q1 to saturate and conduct. At this time, the resistance between the emitter and collector of transistor Q1 is very small, which is equivalent to a closed switch, allowing current to flow through the loop switching subunit and triggering the loop switching action. When the control module outputs a low-level signal, the base current of transistor Q1 is zero, and transistor Q1 is cut off. At this time, the resistance between the emitter and collector of transistor Q1 is very large, which is equivalent to an open switch, preventing current from flowing through the loop switching subunit.

[0045] Furthermore, such as Figure 2 As shown, the loop switching subunit includes: capacitor C1, resistor R3, and transistor Q2; wherein,

[0046] One end of capacitor C1 is electrically connected to the power module, the other end of capacitor C1 is electrically connected to one end of resistor R3, the other end of resistor R3 is electrically connected to the collector of transistor Q2, and the emitter of transistor Q2 is electrically connected to the relay switch unit.

[0047] The end of resistor R3 that is not electrically connected to capacitor C1 is electrically connected to the emitter of transistor Q2, and the end of resistor R3 that is electrically connected to capacitor C1 is electrically connected to the base of transistor Q2.

[0048] Specifically, capacitor C1 acts as an energy storage element, providing instantaneous current during circuit switching to maintain the relay's closed state or help the relay disconnect quickly; resistor R3 acts as a current-limiting resistor, protecting transistor Q2 from damage by excessive current and participating in the bias circuit of transistor Q2; transistor Q2 acts as a switching element, controlling the relay's closing according to the output signal of the circuit control subunit (transmitted through transistor Q1).

[0049] Specifically, one end of capacitor C1 is electrically connected to the power module to receive a stable DC voltage; the other end of capacitor C1 is electrically connected to one end of resistor R3 to form a discharge circuit for the capacitor; the other end of resistor R3 (the end not directly connected to capacitor C1) is electrically connected to the collector of transistor Q2; the emitter of transistor Q2 is connected to the other end of the coil of relay switch K1; the end of resistor R3 connected to capacitor C1 is also connected to the base of transistor Q2 through a small resistor or directly.

[0050] For example, when the loop control subunit (through transistor Q1) outputs a high-level signal, the base voltage of transistor Q2 increases, causing it to conduct; at this time, the power supply module provides a large current to the relay switch K1 through capacitor C1, resistor R3 and transistor Q2, causing it to close quickly. Here, capacitor C1 plays the role of smoothing the current and providing instantaneous energy.

[0051] Furthermore, such as Figure 2 As shown, the loop switching subunit also includes: resistor R4; wherein,

[0052] One end of resistor R4 is electrically connected to the collector of transistor Q2, and the other end of resistor R4 is electrically connected to the emitter of transistor Q2.

[0053] Specifically, resistor R4 is connected between the collector and emitter of transistor Q2, providing an additional current path for transistor Q2 to help discharge when it is off; one end of resistor R4 is electrically connected to the collector of transistor Q2, and the other end is electrically connected to the emitter of transistor Q2, forming a discharge circuit in parallel with transistor Q2.

[0054] For example, when transistor Q2 is turned on, the power module provides a large current to the relay through resistor R3, capacitor C1 (if capacitor C1 is charging or fully charged at this time), and transistor Q2, causing it to close quickly. Resistor R4 has a relatively small impact on the circuit at this time because most of the current flows through transistor Q2. After a certain delay, transistor Q2 is turned off. If capacitor C1 has been charged, it may discharge through the parallel circuit formed by resistors R3 and R4. The presence of resistor R4 provides an additional discharge path for capacitor C1, which helps to accelerate the discharge process of capacitor C1 and ensures that the voltage between the collector and emitter of transistor Q2 drops quickly to a safe level. When it is necessary to switch to a low-current drive circuit, transistor Q2 is turned off, and discharges through the parallel circuit formed by resistors R3 and R4, forming a low-current drive circuit. The low-current drive circuit maintains the closed state of the relay switch unit while reducing the current to prevent the internal coil of the relay switch unit from overheating.

[0055] Furthermore, such as Figure 2 As shown, the accelerated shutdown unit includes diode D1, capacitor C2, resistor R5, and transistor Q3; wherein,

[0056] The input terminal of diode D1 is electrically connected to the power module, the output terminal of diode D1 is electrically connected to one end of capacitor C2, the other end of capacitor C2 is electrically connected to one end of resistor R5, and the other end of resistor R5 is electrically connected to the ground terminal.

[0057] One end of capacitor C2, which is electrically connected to diode D1, is electrically connected to the relay switch unit. The collector of transistor Q3 is electrically connected to the power supply module. The emitter of transistor Q3 is electrically connected to the end of capacitor C2 and resistor R5.

[0058] Specifically, diode D1 can withstand the output voltage of the power module and has a sufficiently fast response time. Its main function is unidirectional conduction to prevent reverse current flow. Capacitor C2 can be an electrolytic capacitor with appropriate capacity to store charge and release it when needed to accelerate the turn-off process. Resistor R5 is used to limit current and protect other components in the circuit.

[0059] Furthermore, such as Figure 2 As shown, the accelerated shutdown unit also includes: resistor R6; wherein,

[0060] One end of resistor R6 is electrically connected to the base of transistor Q3, and the other end of resistor R6 is electrically connected to the emitter of transistor Q1.

[0061] Specifically,

[0062] For example, when the relay needs to be closed, transistor Q1 is turned on, and a high-level signal is sent to the base of transistor Q3 through resistor R6, causing transistor Q3 to turn on; this provides a charging path for the storage capacitor C2 (usually an electrolytic capacitor); at this time, the negative terminal of capacitor C2 (i.e., the end connected to the emitter of transistor Q3) is charged to the power module voltage; when the relay needs to be opened, the control module sends a low-level signal to turn off transistor Q1 in the loop control subunit; at the same time, transistor Q3 in the accelerated turn-off unit is also turned off due to the change in the control signal; when transistor Q3 is turned off... When the capacitor C2 stops, it loses its charging path and, due to the characteristics of a capacitor, it begins to discharge through the relay coil and other possible discharge paths (such as resistor R5). Since capacitor C2 has stored energy and is now required to discharge quickly, it will reduce its negative terminal voltage to zero (or close to zero) in a very short time. Since the positive terminal of capacitor C2 is usually connected to the power module and the negative terminal voltage has been reduced to zero, the voltage difference across the coil of relay switch K1 decreases rapidly to zero, causing the current in the relay coil to decrease rapidly to zero, thereby accelerating the rapid disconnection of relay switch K1.

[0063] Furthermore, such as Figure 2 As shown, the relay switch unit includes: relay switch K1; wherein,

[0064] One end of relay switch K1 is electrically connected to the emitter of transistor Q2, and the other end of relay switch K1 is electrically connected to capacitor C2.

[0065] Specifically, one end of relay switch K1 (assuming it is the normally open contact) is connected to the emitter of transistor Q2 via a wire. When transistor Q2 is in the conducting state, its emitter outputs a current, which flows through relay switch K1, causing the normally open contact of relay switch K1 to close. The other end of relay switch K1 (the other end opposite the normally open contact) is connected to capacitor C2 via a wire. Here, capacitor C2 plays a key role in the accelerated shutdown unit. It is used to store and release electrical energy to achieve rapid shutdown of the relay.

[0066] For example, suppose the uninterruptible power supply (UPS) needs to switch to the backup power supply. The control module outputs a high-level signal to the circuit switching unit. Upon receiving the signal, the circuit switching unit switches to a high-current drive circuit, turning on transistor Q2. After transistor Q2 turns on, the current output from its emitter flows through relay switch K1, closing its normally open contact and connecting the backup power circuit. When relay switch K1 needs to be turned off, the control module outputs a low-level signal to the accelerated turn-off unit. Upon receiving the signal, the accelerated turn-off unit controls transistor Q3 to turn off, and capacitor C2 begins to discharge. Since the negative terminal of capacitor C2 is connected to ground through transistor Q3, its voltage drops rapidly. One end of relay switch K1 is connected to capacitor C2, so the drive level of K1 also drops rapidly, thus achieving rapid relay turn-off.

[0067] Furthermore, such as Figure 2 As shown, the relay switch unit also includes: diode D2; wherein,

[0068] The input terminal of diode D2 is electrically connected to the emitter of transistor Q2, and the output terminal of diode D2 is electrically connected to capacitor C2.

[0069] Specifically, diode D2 mainly plays a protective role here. When relay switch K1 is closed, if the emitter voltage of transistor Q2 increases instantaneously due to some reason (such as power fluctuation, load change, etc.), diode D2 can quickly conduct, introducing the excess current into capacitor C2, thereby preventing transistor Q2 from being damaged due to overvoltage. At the same time, capacitor C2 can also smooth voltage fluctuations, further protecting the stable operation of the circuit.

[0070] For example, when the system receives a signal indicating a mains power failure, the control module immediately outputs a high-level signal. This high-level signal activates transistor Q2 through the high-current drive circuit of the circuit switching unit, turning on the collector-emitter path of transistor Q2 and driving relay switch K1 to close rapidly. After relay switch K1 closes, the system switches to inverter mode, providing uninterrupted power supply to the load. After a delay, transistor Q2 turns off, and current flows through resistor R4 to form a low-current drive circuit. This low-current drive circuit maintains the closed state of the relay switch unit while reducing the current to prevent the internal coil of the relay switch unit from overheating. During system operation, if the emitter voltage of transistor Q2 increases instantaneously, diode D2 quickly conducts, introducing excess current into capacitor C2 to protect transistor Q2 from damage. When it is necessary to turn off relay switch K1, the control module outputs a low-level signal, which instantly pulls the drive level of relay switch K1 to zero through the accelerated turn-off unit, achieving rapid turn-off.

[0071] Based on the same inventive concept, such as Figure 3As shown, the present invention also provides an automatic switching method for uninterruptible power supplies (UPS) in a power grid, applied to the aforementioned automatic switching system for UPS, the method comprising:

[0072] The high-level signal control circuit switches to the high-current drive circuit, causing the relay switch K1 to close quickly.

[0073] After a predetermined delay, the high-current drive circuit will automatically switch to the low-current drive circuit, keeping relay switch K1 in the closed state.

[0074] When it is necessary to turn off relay switch K1, the low-level signal controls the accelerated turn-off unit to instantly pull the drive level of relay switch K1 down to zero, thereby speeding up the turn-off time of relay switch K1.

[0075] Based on the same inventive concept, the present invention also provides an automatic switching drive circuit for uninterruptible power supply in the power grid, the drive circuit including an automatic switching system for uninterruptible power supply in the power grid as described above.

[0076] It should be noted that the electrical connections between the various units described above do not necessarily represent connections between circuits. Indirect connections are acceptable as long as they achieve the objectives of this invention. The above are merely exemplary embodiments of this invention and should not be construed as limiting the scope of the invention.

[0077] All equivalent changes and modifications made in accordance with the teachings of this invention are still within the scope of this invention. Those skilled in the art will readily conceive of other embodiments of this invention upon considering the specification and the disclosure of practical truth. This application is intended to cover any variations, uses, or adaptations of this invention that follow the general principles of this invention and include common knowledge or conventional techniques in the art not described herein.

Claims

1. A grid uninterruptible power supply automatic transfer system, characterized by, The system includes: a power supply module, a switching module, and a control module. The switching module includes a relay switch unit, an accelerated shutdown unit, and a circuit switching unit. The power module is electrically connected to the acceleration shutdown unit and the circuit switching unit respectively, and is used to provide power to the system. The relay switch unit is connected to the accelerated shutdown unit and the circuit switching unit respectively, and is used to control the on / off of the mains power input; The accelerated shutdown unit is electrically connected to the relay switch unit and the power module respectively, and is used to accelerate the shutdown of the relay switch unit. The circuit switching unit is electrically connected to the power module, the accelerated shutdown unit and the relay switch unit respectively, and is used to switch the high current drive circuit to a low current drive circuit after a predetermined delay time. The control module is electrically connected to the circuit switching unit and is used to output a high-level signal to control the circuit switching unit to switch the high-current drive circuit and accelerate the closing of the relay switch unit; the control module is also electrically connected to the acceleration shutdown unit and is used to output a low-level signal to control the acceleration shutdown unit to accelerate the shutdown of the relay switch unit. The circuit switching unit includes a loop control subunit and a loop switching subunit. The loop control subunit includes resistors R1 and R2 and a transistor Q1. One end of the resistor R1 is electrically connected to the control module, the other end of the resistor R1 is electrically connected to the base of the transistor Q1 and one end of the resistor R2, the other end of the resistor R2 is electrically connected to the collector and ground of the transistor Q1, and the emitter of the transistor Q1 is electrically connected to the loop switching subunit. The circuit switching subunit includes: capacitor C1, resistor R3, and transistor Q2; wherein... One end of the capacitor C1 is electrically connected to the power module, the other end of the capacitor C1 is electrically connected to one end of the resistor R3, the other end of the resistor R3 is electrically connected to the collector of the transistor Q2, and the emitter of the transistor Q2 is electrically connected to the relay switch unit. The end of resistor R3 that is not electrically connected to capacitor C1 is electrically connected to the emitter of transistor Q2, and the end of resistor R3 that is electrically connected to capacitor C1 is electrically connected to the base of transistor Q2. The circuit switching subunit further includes: resistor R4; wherein... One end of the resistor R4 is electrically connected to the collector of the transistor Q2, and the other end of the resistor R4 is electrically connected to the emitter of the transistor Q2. The accelerated shutdown unit includes a diode D1, a capacitor C2, a resistor R5, and a transistor Q3; wherein, The input terminal of diode D1 is electrically connected to the power module, the output terminal of diode D1 is electrically connected to one end of capacitor C2, the other end of capacitor C2 is electrically connected to one end of resistor R5, and the other end of resistor R5 is electrically connected to the ground terminal. One end of the capacitor C2, which is electrically connected to the diode D1, is electrically connected to the relay switch unit. The collector of the transistor Q3 is electrically connected to the power module. The emitter of the transistor Q3 is electrically connected to one end of the capacitor C2 and the resistor R5. The relay switch unit further includes: diode D2; wherein... The input terminal of diode D2 is electrically connected to the emitter of transistor Q2, and the output terminal of diode D2 is electrically connected to capacitor C2.

2. The electrical grid uninterruptible power supply automatic transfer system of claim 1, wherein, The accelerated shutdown unit further includes: resistor R6; wherein... One end of the resistor R6 is electrically connected to the base of the transistor Q3, and the other end of the resistor R6 is electrically connected to the emitter of the transistor Q1.

3. The electrical grid uninterruptible power supply automatic transfer system of claim 2, wherein, The relay switch unit includes: relay switch K1; wherein... One end of the relay switch K1 is electrically connected to the emitter of the transistor Q2, and the other end of the relay switch K1 is electrically connected to the capacitor C2.

4. A method for grid UPS automatic switching, applied to the grid UPS automatic switching system of any one of claims 1-3, characterized in that, The method includes: The high-level signal control circuit switches to the high-current drive circuit, causing the relay switch K1 to close quickly. After a predetermined delay, the high-current drive circuit will automatically switch to the low-current drive circuit, keeping the relay switch K1 in the closed state. When it is necessary to turn off the relay switch K1, the low-level signal controls the accelerated turn-off unit to instantly pull the drive level of the relay switch K1 down to zero, thereby speeding up the turn-off time of the relay switch K1.

5. A grid uninterruptible power supply automatic transfer switch drive circuit, characterized by, The drive circuit includes the automatic switching system for uninterruptible power supply as described in any one of claims 1-3.

Images