Commercial power and UPS power supply rapid switching interlocking circuit

Abstract

The utility model provides a mains supply and UPS power supply rapid switching interlock circuit, which solves the problem that mains supply and UPS alternating current are possibly output at the same time, and comprises a mains supply input unit and a UPS input unit which are respectively connected with an alternating current user terminal device through a solid-state relay. The solid-state relay is connected with a driving interlocking circuit, the driving interlocking circuit is provided with a microcontroller circuit, and the microcontroller circuit is connected with a mains supply input unit through an alternating current power failure detection circuit. The utility model has the advantages of stable structure, good safety and the like.

Description

Technical Field

[0001] The utility model belongs to the technical field of power supply equipment, and in particular relates to a fast switching interlocking circuit between mains power and UPS power supply. Background Art

[0002] Most of the AC power and UPS AC power switching on the market now use 220VAC AC relays as the core components to switch dual power supplies. Although the AC power and UPS AC power switching functions can be realized, many problems will be exposed in actual engineering applications, such as relay sparking and burning, which is a common fault. In addition, the primary voltage in the power grid is not a stable value. It can fluctuate within a certain range, up to 1.2 times UR (UR = 220VAC), but the maximum voltage that the AC relay coil can withstand is generally 1.1 times UR, and 0.8 times UR is a reliable action voltage threshold. Therefore, when the AC voltage is greater than 1.1 times UR, long-term work will cause the AC relay coil to burn and fail. When the AC is near 0.8 times UR, it is just stuck near the AC relay action threshold. At this time, the relay will frequently operate and reset under load. Such jitter will burn the relay. In addition, the AC relay is prone to arcing when switching with power, causing potential damage.

[0003] In order to solve the deficiencies of the prior art, people have conducted long-term exploration and proposed various solutions. For example, a Chinese patent document discloses a UPS power switching device [201310530327.5], which includes a mains power supply module, an external power supply module, a battery power supply module, a battery charging module, an MCU control module, a switching control module and a host power output module. When the mains power is supplied, the host power output module is controlled to directly reduce the mains power to a reference power output. When the MCU control module determines that the mains power is off through power-off waveform recognition and peak voltage detection, the switching instruction is output to the switching control module to realize the switching between the mains power supply module, the external power supply module and the battery power supply module.

[0004] The above solution solves the problem of switching between AC power and UPS power to a certain extent, but the solution still has many shortcomings, such as the problem that AC power and UPS AC power may be output at the same time. Summary of the invention

[0005] The utility model aims to solve the above problems and provide a reasonably designed interlocking circuit for quickly switching between AC power and UPS power supply, which can effectively prevent the AC power and UPS AC power from being output simultaneously.

[0006] To achieve the above-mentioned purpose, the utility model adopts the following technical solutions: a fast switching interlocking circuit between AC power and UPS power supply, including a AC power input unit and a UPS input unit, the AC power input unit and the UPS input unit are respectively connected to the AC user terminal equipment through solid-state relays, the solid-state relays are connected to the drive interlocking circuit, the drive interlocking circuit is equipped with a microcontroller circuit connection, and the microcontroller circuit is connected to the AC power input unit through an AC power-off detection circuit.

[0007] In the above-mentioned interlocking circuit for fast switching between AC power and UPS power supply, the AC power failure detection circuit includes an industrial frequency transformer T1 connected to the AC power input unit, the industrial frequency transformer T1 is connected to the high-speed isolation optocoupler U1 with a resistor R9 arranged therebetween, and a resistor R10 is connected between the high-speed isolation optocoupler U1 and the microcontroller circuit.

[0008] In the above-mentioned interlocking circuit for fast switching between AC power and UPS power supply, the drive interlocking circuit includes a high-speed isolation optocoupler U2 connected to the AC power input unit, a resistor R1 is connected between the AC power input unit and the high-speed isolation optocoupler U2, the high-speed isolation optocoupler U2 is connected to the solid-state relay through the transistor Q1, a grounded resistor R3 is connected between the transistor Q1 and the high-speed isolation optocoupler U2, and a resistor R2 is connected between the transistor Q1 and the solid-state relay.

[0009] In the above-mentioned interlocking circuit for fast switching between AC power and UPS power supply, the UPS input unit is connected to a high-speed isolation optocoupler U3, a resistor R6 is connected between the UPS input unit and the high-speed isolation optocoupler U3, the high-speed isolation optocoupler U3 is connected to the solid-state relay through the transistor Q2, a grounded resistor R8 is connected between the transistor Q2 and the high-speed isolation optocoupler U2, and a resistor R7 is connected between the transistor Q2 and the solid-state relay.

[0010] In the above-mentioned interlocking circuit for fast switching between AC power and UPS power supply, transistor Q1 is connected between resistor R8 and transistor Q2 through resistor R4, and transistor Q2 is connected between resistor R3 and transistor Q1 through resistor R5.

[0011] In the above-mentioned interlocking circuit for fast switching between AC power and UPS power supply, the microcontroller circuit includes an MCU module U4, and the MCU module U4 is a PIC18F43K22 model.

[0012] In the above-mentioned interlocking circuit for fast switching between AC power and UPS power supply, the MCU module U4 is connected to a resistor R11 and a resistor R12, the resistor R11 is connected in parallel with a diode D1, and the diode D1 is connected to a capacitor C3.

[0013] In the above-mentioned interlocking circuit for fast switching between AC power and UPS power supply, the MCU module U4 is connected to the transistor Y1, and the transistor Y1 is connected to the capacitor C1 and the capacitor C2; the MCU module U4 is connected to the capacitors C4 and C5 in parallel.

[0014] In the above-mentioned interlocking circuit for fast switching between AC power and UPS power supply, the MCU module U4 is equipped with a MOS tube Q1, and the MOS tube Q1 is connected to a resistor R13, a resistor R14 and a resistor R15.

[0015] In the above-mentioned interlocking circuit for fast switching between AC power and UPS power supply, a varistor is built into the solid-state relay.

[0016] Compared with the existing technology, the advantages of the utility model are: the switching between the mains power and the UPS AC power adopts a hardware-driven interlocking circuit, which can effectively solve the situation of false triggering and driving two sets of solid-state relays at the same time, thereby improving the safety of power supply use; the microcontroller circuit can quickly respond to drive the UPS solid-state relay and the mains solid-state relay, so that the mains power and UPS power can supply power to AC users; it is equipped with an AC power failure detection circuit, so as to detect in real time whether the mains power is lost. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is the structural principle diagram of the utility model;

[0018] Figure 2 It is a circuit diagram of the AC power failure detection circuit of the utility model;

[0019] Figure 3 It is a circuit diagram of the drive interlocking circuit of the utility model;

[0020] Figure 4 It is a circuit diagram of a microcontroller circuit of the utility model;

[0021] In the figure, there are a mains input unit 1, a UPS input unit 2, a solid-state relay 3, an AC user terminal device 4, a drive interlock circuit 5, a microcontroller circuit 6, and an AC power-off detection circuit 7. DETAILED DESCRIPTION

[0022] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0023] like Figure 1-4As shown, a fast switching interlock circuit between AC power and UPS power supply is mainly used to solve the problems that AC relays are easily damaged when switching between AC power and UPS AC power, and AC power of AC and UPS may be output at the same time. It specifically includes a AC input unit 1 and a UPS input unit 2. The AC input unit 1 and the UPS input unit 2 are respectively connected to the AC user terminal device 4 through a solid-state relay 3, wherein the solid-state relay 3 adopts low-voltage control and has a zero-crossing start function to reduce noise during operation. The solid-state relay 3 is connected to the drive interlock circuit 5, and the hardware method is used to solve the problem of false triggering and driving two groups of solid-state relays 3 at the same time. The drive interlock circuit 5 is equipped with a microcontroller circuit 6 connection, and the microcontroller circuit 6 is connected to the AC input unit 1 through an AC power-off detection circuit 7. The AC power-off detection circuit 7 adopts a transformer plus an isolation optocoupler, and the signal is connected to the external interrupt pin of the microcontroller circuit 6 to quickly detect the AC power off.

[0024] Specifically, the AC power failure detection circuit 7 includes an industrial frequency transformer T1 connected to the mains input unit 1 , the industrial frequency transformer T1 is connected to the high-speed isolation optocoupler U1 with a resistor R9 arranged therebetween, and a resistor R10 is connected between the high-speed isolation optocoupler U1 and the microcontroller circuit 6 .

[0025] When there is AC input, the secondary side measurement of the power frequency transformer T1 generates an AC sine wave with a peak value of 5V and a period of 20ms. The resistor R9 is used as the current limiting resistor of the high-speed isolation optocoupler U1. After the input of the high-speed isolation optocoupler U1, the secondary side measurement of the high-speed isolation optocoupler U1 generates a square wave with a period of 10ms and transmits it to the external interrupt pin of the microcontroller circuit 6. The advantage of this circuit is that the power frequency transformer T1 and the high-speed isolation optocoupler U1 separate the strong and weak grounds, and the waveform with a period of 20ms is changed into a waveform with a period of 10ms, thereby shortening the detection time.

[0026] In depth, the drive interlock circuit 5 includes a high-speed isolation optocoupler U2 connected to the AC input unit 1, a resistor R1 is connected between the AC input unit 1 and the high-speed isolation optocoupler U2, the high-speed isolation optocoupler U2 is connected to the solid-state relay 3 through the transistor Q1, a grounded resistor R3 is connected between the transistor Q1 and the high-speed isolation optocoupler U2, and a resistor R2 is connected between the transistor Q1 and the solid-state relay 3.

[0027] Furthermore, the UPS input unit 2 is connected to a high-speed isolation optocoupler U3, a resistor R6 is connected between the UPS input unit 2 and the high-speed isolation optocoupler U3, the high-speed isolation optocoupler U3 is connected to the solid-state relay 3 through the transistor Q2, a grounded resistor R8 is connected between the transistor Q2 and the high-speed isolation optocoupler U2, and a resistor R7 is connected between the transistor Q2 and the solid-state relay 3.

[0028] Furthermore, the transistor Q1 is connected between the resistor R8 and the transistor Q2 through the resistor R4, and the transistor Q2 is connected between the resistor R3 and the transistor Q1 through the resistor R5.

[0029] Resistors R1 and R6 serve as current limiting resistors for high-speed isolation optocouplers U2 and U3. When the mains drive signal is given to the isolation optocoupler U2 and there is no mains drive signal from the UPS input unit 2, the emitter terminal of the transistor Q1 becomes a high voltage, the base terminal is a low voltage, and the transistor Q1 is turned on as a switch; the base terminal of the transistor Q2 becomes a high voltage, the emitter terminal is a low voltage, and the transistor Q2 is turned off as a switch; a high voltage is generated at the resistor R2 end to drive the solid-state relay 3; when the UPS input unit 2 drive signal is given to the isolation optocoupler U3 and there is no mains drive signal, the emitter terminal of the transistor Q2 becomes a high voltage, the base terminal is a low voltage, and the transistor Q2 is turned on as a switch; the base terminal of the transistor Q1 becomes a high voltage, the emitter terminal is a low voltage, and the transistor Q1 is turned off as a switch; a high voltage is generated at the resistor R1 end to drive the solid-state relay 3; if the mains drive signal and the UPS input drive signal are present at the same time, Q1 and Q2 are both turned off at the same time.

[0030] The advantage of this circuit is that if the UPS input drive signal and the AC power drive signal are given by mistake at the same time, the solid-state relay 3 will not be turned on at the same time to allow the AC power and UPS power to be output at the same time to burn the AC user terminal equipment 4.

[0031] In addition, the microcontroller circuit 6 includes an MCU module U4, and the MCU module U4 is a PIC18F43K22 model.

[0032] Meanwhile, the MCU module U4 is connected to a resistor R11 and a resistor R12 , the resistor R11 is connected in parallel with a diode D1 , and the diode D1 is connected to a capacitor C3 .

[0033] It can be seen that the MCU module U4 is connected to the transistor Y1, and the transistor Y1 is connected to the capacitor C1 and the capacitor C2; the MCU module U4 is connected to the capacitors C4 and C5 in parallel.

[0034] Obviously, the MCU module U4 is equipped with a MOS tube Q1, and the MOS tube Q1 is connected to a resistor R13, a resistor R14 and a resistor R15.

[0035] When the AC power failure detection circuit 7 detects that the mains power is input, it transmits the signal to the external interrupt pin of the microcontroller circuit 6. When the microcontroller circuit 6 receives the external signal, it starts the timer function. Within the time of 20ms, if the square wave of the external signal always exists, the microcontroller circuit 6 determines that the mains power input exists, and the microcontroller circuit 6 outputs the mains power control signal to the drive interlock circuit 5. The drive interlock circuit 5 switches the solid-state relay 3 to the on state, so that the mains power is supplied to the AC user terminal equipment. If within the 20ms time when the timer is turned on, the AC power failure detection circuit 7 does not send a signal to the external interrupt pin of the microcontroller circuit 6, the microcontroller circuit 6 determines that there is no mains power input, and the microcontroller circuit 6 outputs the UPS control signal to the drive interlock circuit 5. The drive interlock circuit 5 switches the solid-state relay 3 to the on state, so that the UPS supplies the AC user terminal equipment 4. This solution can ensure that the switching time between the UPS input and the mains power input is controlled within 40ms.

[0036] Preferably, the solid-state relay 3 has a built-in varistor to effectively absorb external surges.

[0037] To sum up, the principle of this embodiment is that the solid-state relays 3 of the AC power input unit 1 and the UPS input unit 2 are switched by the drive interlock circuit 5, and the AC power failure detection circuit 7 of the microcontroller circuit 6 detects the AC power failure. If there is no AC power, the AC power failure detection circuit 7 is controlled to switch to avoid the solid-state relays 3 from being turned on synchronously.

[0038] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

[0039] Although this article uses more terms such as mains input unit 1, UPS input unit 2, solid-state relay 3, AC user terminal device 4, drive interlock circuit 5, microcontroller circuit 6, AC power failure detection circuit 7, etc., it does not exclude the possibility of using other terms. These terms are used only to more conveniently describe and explain the essence of the utility model; interpreting them as any additional restrictions is contrary to the spirit of the utility model.

Claims

1. A fast switching interlocking circuit between mains power and UPS power supply, comprising a mains power input unit (1) and a UPS input unit (2), wherein the mains power input unit (1) and the UPS input unit (2) are respectively connected to an AC user terminal device (4) via a solid-state relay (3), characterized in that: The solid-state relay (3) is connected to a drive interlock circuit (5), the drive interlock circuit (5) is connected to a microcontroller circuit (6), and the microcontroller circuit (6) is connected to a mains input unit (1) via an AC power failure detection circuit (7).

2. A fast switching interlocking circuit between AC power and UPS power supply according to claim 1, characterized in that: The AC power failure detection circuit (7) comprises an industrial frequency transformer T1 connected to the mains input unit (1); the industrial frequency transformer T1 is connected to a high-speed isolation optocoupler U1 with a resistor R9 provided therebetween; and a resistor R10 is connected between the high-speed isolation optocoupler U1 and the microcontroller circuit (6).

3. A fast switching interlocking circuit between AC power and UPS power supply according to claim 1, characterized in that: The drive interlock circuit (5) comprises a high-speed isolation optocoupler U2 connected to the mains input unit (1); a resistor R1 is connected between the mains input unit (1) and the high-speed isolation optocoupler U2; the high-speed isolation optocoupler U2 is connected to the solid-state relay (3) via a transistor Q1; a grounded resistor R3 is connected between the transistor Q1 and the high-speed isolation optocoupler U2; and a resistor R2 is connected between the transistor Q1 and the solid-state relay (3).

4. A fast switching interlocking circuit between AC power and UPS power supply according to claim 3, characterized in that: The UPS input unit (2) is connected to a high-speed isolation optocoupler U3, a resistor R6 is connected between the UPS input unit (2) and the high-speed isolation optocoupler U3, the high-speed isolation optocoupler U3 is connected to a solid-state relay (3) via a transistor Q2, a grounded resistor R8 is connected between the transistor Q2 and the high-speed isolation optocoupler U2, and a resistor R7 is connected between the transistor Q2 and the solid-state relay (3).

5. The interlocking circuit for fast switching between mains power and UPS power supply according to claim 3, characterized in that: The transistor Q1 is connected between the resistor R8 and the transistor Q2 via the resistor R4, and the transistor Q2 is connected between the resistor R3 and the transistor Q1 via the resistor R5.

6. A fast switching interlocking circuit between AC power and UPS power supply according to claim 1, characterized in that: The microcontroller circuit (6) comprises an MCU module U4, and the MCU module U4 is a PIC18F43K22 model.

7. A fast switching interlocking circuit between AC power and UPS power supply according to claim 6, characterized in that: The MCU module U4 is connected to a resistor R11 and a resistor R12, the resistor R11 is connected in parallel with a diode D1, and the diode D1 is connected to a capacitor C3.

8. The interlocking circuit for fast switching between AC power and UPS power supply according to claim 6, characterized in that: The MCU module U4 is connected to a transistor Y1, and the transistor Y1 is connected to capacitors C1 and C2; the MCU module U4 is connected to capacitors C4 and C5 in parallel.

9. A fast switching interlocking circuit between AC power and UPS power supply according to claim 6, characterized in that: The MCU module U4 is equipped with a MOS tube Q1, and the MOS tube Q1 is connected to a resistor R13, a resistor R14 and a resistor R15.

10. The interlocking circuit for fast switching between AC power and UPS power supply according to claim 1, characterized in that: The solid-state relay (3) has a built-in varistor.

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