UPS DC bus overvoltage short circuit protection device

Abstract

The utility model relates to the technical field of UPS power supply protection, and discloses a UPS DC bus overvoltage short circuit protection device comprising a digital signal processor; a control circuit; a rectification filter circuit; an overvoltage protection circuit; a short circuit protection circuit; through the design of the rectification filter circuit, input alternating current is converted into direct current, stable direct current input is provided for the UPS, high-frequency harmonic waves and noise in the alternating current input can be filtered out, it is ensured that voltage waveforms on a direct current bus are pure and stable, and interference to the UPS and other equipment is reduced; through the design of the overvoltage protection circuit, when the voltage on the direct current bus exceeds a set threshold value, the power supply is cut off or the voltage is reduced rapidly, and the UPS power supply and load equipment are protected. Through the design of the short-circuit protection circuit, when a DC bus short-circuit fault is detected, an IGBT driving signal of the PWM controller is blocked, bypass output or closed output is switched in time, and load equipment is protected from being impacted and damaged by short-circuit current.

Description

Technical Field

[0001] This utility model relates to the field of UPS power supply protection technology, specifically a UPS DC bus overvoltage and short circuit protection device. Background Technology

[0002] A UPS (Uninterruptible Power Supply) is a power protection system for electrical equipment, containing an energy storage device and primarily composed of an inverter. It features voltage stabilization, frequency stabilization, filtering, electromagnetic and radio frequency interference suppression, and voltage surge protection. Its purpose is to provide safe, reliable, and stable uninterrupted AC power to critical equipment and systems under normal, abnormal, and power outage conditions. The DC bus is a crucial component of the UPS, connecting the rectifier, inverter, and battery pack. It is responsible for transmitting the DC power converted by the rectifier to the inverter and also serves as a channel for the battery pack to supply power to the inverter.

[0003] In existing technologies, high-frequency harmonics and noise exist on the DC bus of a UPS, which can interfere with the UPS power supply and other equipment. When the voltage on the DC bus exceeds a set threshold, the UPS power supply and load equipment will be damaged due to overvoltage. Therefore, we need to propose a UPS DC bus overvoltage and short-circuit protection device to enable the UPS power system to maintain stable output voltage and current under various complex and harsh operating conditions, and provide reliable power protection for the load equipment. Utility Model Content

[0004] The purpose of this invention is to provide a UPS DC bus overvoltage and short-circuit protection device. Through the design of a rectifier and filter circuit, the input AC power is converted to DC power, providing a stable DC input to the UPS and filtering out high-frequency harmonics and noise from the AC input. This ensures a clean and stable voltage waveform on the DC bus, reducing interference to the UPS power supply and other equipment. The overvoltage protection circuit design can quickly cut off the power supply or reduce the voltage when the DC bus voltage exceeds a set threshold, protecting the UPS power supply and load equipment. The short-circuit protection circuit design, upon detecting a DC bus short-circuit fault, blocks the IGBT drive signal of the PWM controller and outputs a circuit signal to the digital signal processor, promptly switching to bypass output or shutting down the output to protect the load equipment from the impact and damage of short-circuit current, thus solving the problems mentioned in the background art.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a UPS DC bus overvoltage short circuit protection device, comprising:

[0006] Digital signal processor;

[0007] Control circuits responsible for monitoring and adjusting the operating status of the UPS power supply;

[0008] A rectifier and filter circuit used to convert input AC power to DC power and filter out high-frequency interference and fluctuations in AC power;

[0009] An overvoltage protection circuit used to automatically disconnect the power supply circuit when there is an overvoltage on the DC bus;

[0010] A short-circuit protection circuit used to block the IGBT drive signal from the PWM controller and output a DC bus short-circuit signal to the digital signal processor when the DC bus is short-circuited.

[0011] The rectifier filter circuit, overvoltage protection circuit, and short-circuit protection circuit are all connected to the digital signal processor and control circuit. The overvoltage protection circuit and short-circuit protection circuit are all connected to the rectifier filter circuit, and the digital signal processor and control circuit are connected.

[0012] Preferably, the rectifier filter circuit includes terminal block X1, terminal block X2, terminal block X3, amplifier IC1, and amplifier IC2. An adjustable resistor RP1 is connected between pin 1 and pin 2 of terminal block X1, an adjustable resistor RP2 is connected between pin 2 and pin 3 of terminal block X1, a capacitor C1 is connected between pin 1 of amplifier IC1 and the adjustment terminal of adjustable resistor RP2, and a capacitor C4 is connected between pin 4 of amplifier IC1 and pin 1 of terminal block X2.

[0013] A capacitor C6 is connected between pin 1 of amplifier IC2 and the adjustment terminal of adjustable resistor RP1, and a capacitor C9 is connected between pin 4 of amplifier IC2 and pin 4 of terminal block X2.

[0014] Preferably, a series-connected rectifier diode D1 and rectifier diode D2, and a series-connected rectifier diode D3 and rectifier diode D4 are connected in parallel between pins 1 and 2 of the terminal block X3. A capacitor C11 and a capacitor C12 are also connected in parallel between the terminals of rectifier diodes D1 and D2 and the terminals of rectifier diodes D3 and D4. The terminals of capacitors C11 and C12 are respectively connected to pin 1 of amplifier IC1 and pin 1 of amplifier IC2.

[0015] Preferably, the overvoltage protection circuit includes a chip U810, a transistor Q850, and a transformer T800. A resistor R811 is connected to pin 2 of the chip U810. A capacitor C811 is connected between pins 3 and 6 of the chip U810. Resistors R813 and R814 are connected in parallel between pins 4 and 6 of the chip U810. A resistor R812 is connected between pin 4 of the chip U810 and the collector of the transistor Q850.

[0016] A diode D850 and a capacitor C850 and a resistor R850 are connected in parallel at pin 1 of the transformer T800. A resistor R851 and a capacitor C851 are connected between the diode D850 and pin 2 of the transformer T800. A resistor R852 is connected between the collector and emitter of the transistor Q850. A resistor R853 is connected between the base and collector of the transistor Q850.

[0017] Preferably, a MOSFET Q820 is connected to pin 6 of the transformer T800, the gate (G) of the MOSFET Q820 is connected to pin 1 of the chip U810, a resistor R805 is connected to the source (S) of the MOSFET Q820, a diode D830 is connected to pins 7 and 8 of the transformer T800, and capacitors C831 and C832 are connected in parallel between pin 2 of the diode D830 and pins 9 and 10 of the transformer T800.

[0018] Preferably, the short-circuit protection circuit includes a chip U10 and a transistor Q5. A resistor R28 is connected between pin 1 and pin 4 of the chip U10. A resistor R36 is connected between the collector of the transistor Q5 and pin 4 of the chip U10. A resistor R33 is connected between the terminals of pins 1, 2, and 3 of the chip U10 and the terminals of pins 5, 6, 7, and 8. An inductor L1 and a diode D11 are connected between pins 5 and 8 of the chip U10.

[0019] Preferably, the base of the transistor Q5 is connected to a resistor R34, a diode D10, and a resistor R35, one end of the diode D10 is connected to a resistor R29 and a resistor R30, and a capacitor C21 is connected between the emitter of the transistor Q5 and pin 1 of the chip U10.

[0020] Compared with the prior art, the beneficial effects of this utility model are:

[0021] 1. This utility model converts the input AC power into DC power through the design of a rectifier and filter circuit, providing a stable DC input for the UPS, and can filter out high-frequency harmonics and noise in the AC input, ensuring that the voltage waveform on the DC bus is pure and stable, and reducing interference to the UPS power supply and other equipment.

[0022] 2. This utility model, through the design of an overvoltage protection circuit, can quickly cut off the power supply or reduce the voltage when the voltage on the DC bus exceeds a set threshold, thereby protecting the UPS power supply and load equipment.

[0023] 3. This utility model, through the design of a short-circuit protection circuit, blocks the IGBT drive signal of the PWM controller when a DC bus short-circuit fault is detected, and outputs a circuit signal to the digital signal processor, and promptly switches to bypass output or shuts down output to protect the load equipment from the impact and damage of short-circuit current. Attached Figure Description

[0024] Figure 1 This is a circuit block diagram of the present invention;

[0025] Figure 2 This is a circuit diagram of the rectifier and filter circuit of this utility model;

[0026] Figure 3 This is a circuit diagram of the overvoltage protection circuit of this utility model;

[0027] Figure 4 This is a circuit diagram of the short-circuit protection circuit of this utility model. Detailed Implementation

[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0029] Please see Figure 1-4 This utility model provides a technical solution: a UPS DC bus overvoltage short circuit protection device, comprising:

[0030] Digital signal processor;

[0031] Control circuits responsible for monitoring and adjusting the operating status of the UPS power supply;

[0032] A rectifier and filter circuit used to convert input AC power to DC power and filter out high-frequency interference and fluctuations in AC power;

[0033] The rectifier and filter circuit includes terminal block X1, terminal block X2, terminal block X3, amplifier IC1, and amplifier IC2. An adjustable resistor RP1 is connected between pin 1 and pin 2 of terminal block X1, an adjustable resistor RP2 is connected between pin 2 and pin 3 of terminal block X1, a capacitor C1 is connected between pin 1 of amplifier IC1 and the adjustment terminal of adjustable resistor RP2, and a capacitor C4 is connected between pin 4 of amplifier IC1 and pin 1 of terminal block X2.

[0034] A capacitor C6 is connected between pin 1 of amplifier IC2 and the adjustment terminal of adjustable resistor RP1, and a capacitor C9 is connected between pin 4 of amplifier IC2 and pin 4 of terminal block X2.

[0035] A series-connected rectifier diode D1 and D2, and a series-connected rectifier diode D3 and D4 are connected in parallel between pins 1 and 2 of the terminal block X3. A capacitor C11 and a capacitor C12 are also connected in parallel between the terminals of rectifier diodes D1 and D2 and the terminals of rectifier diodes D3 and D4. The terminals of capacitors C11 and C12 are respectively connected to pin 1 of amplifier IC1 and pin 1 of amplifier IC2.

[0036] Terminal X1 is the DC bus voltage signal input terminal, adjustable resistor RP1 is used to adjust the gain of the input signal, and amplifier IC1 and amplifier IC2 are used to amplify the input signal;

[0037] Resistors R1, R2, R3, R4, R7, and R8 are feedback resistors used to set the gain of the two amplifiers; capacitors C1, C2, C3, C4, C6, and C7 are coupling capacitors used to block DC components and allow AC signals to pass through.

[0038] Terminal X3 is the AC signal input terminal. After rectification by rectifier diodes (D1-D4), it provides DC power to the circuit; capacitor C11 is a filter capacitor, smoothing the rectified DC voltage.

[0039] Terminal X2 is the output terminal for the amplified DC bus voltage signal. Capacitors C5, C9, and C10 are output coupling capacitors to ensure the quality of the output signal.

[0040] An overvoltage protection circuit used to automatically disconnect the power supply circuit when there is an overvoltage on the DC bus;

[0041] The overvoltage protection circuit includes a chip U810, a transistor Q850, and a transformer T800. A resistor R811 is connected to pin 2 of the chip U810. A capacitor C811 is connected between pins 3 and 6 of the chip U810. Resistors R813 and R814 are connected in parallel between pins 4 and 6 of the chip U810. A resistor R812 is connected between pin 4 of the chip U810 and the collector of the transistor Q850.

[0042] A diode D850 and a capacitor C850 and a resistor R850 are connected in parallel at pin 1 of the transformer T800. A resistor R851 and a capacitor C851 are connected between the diode D850 and pin 2 of the transformer T800. A resistor R852 is connected between the collector and emitter of the transistor Q850. A resistor R853 is connected between the base and collector of the transistor Q850.

[0043] A MOSFET Q820 is connected to pin 6 of the transformer T800. The gate of the MOSFET Q820 is connected to pin 1 of the chip U810. A resistor R805 is connected to the source of the MOSFET Q820. A diode D830 is connected to pins 7 and 8 of the transformer T800. Capacitors C831 and C832 are connected in parallel between pin 2 of the diode D830 and pins 9 and 10 of the transformer T800.

[0044] Chip U850 is the main control chip, responsible for regulating the output voltage and controlling the switching elements. Diodes D830 and D831 are used to prevent reverse current. Resistors R805 and R811 are used for current limiting and voltage division. Transistor Q820 is used to control the flow of current.

[0045] A short-circuit protection circuit used to block the IGBT drive signal from the PWM controller and output a DC bus short-circuit signal to the digital signal processor when the DC bus is short-circuited.

[0046] The short-circuit protection circuit includes a chip U10 and a transistor Q5. A resistor R28 is connected between pin 1 and pin 4 of the chip U10. A resistor R36 is connected between the collector of the transistor Q5 and pin 4 of the chip U10. A resistor R33 is connected between the terminals of pins 1, 2, and 3 of the chip U10 and the terminals of pins 5, 6, 7, and 8. An inductor L1 and a diode D11 are connected between pins 5 and 8 of the chip U10.

[0047] The base of transistor Q5 is connected to resistor R34, diode D10, and resistor R35. One end of diode D10 is connected to resistor R29 and resistor R30. Capacitor C21 is connected between the emitter of transistor Q5 and pin 1 of chip U10.

[0048] Capacitor C21 is a filter capacitor that smooths the input voltage and reduces power supply noise. Chip U10 is a PWM controller responsible for generating pulse width modulation signals to control the output voltage and current. Inductor L1 is used to store energy and smooth the output current.

[0049] The rectifier filter circuit, overvoltage protection circuit, and short-circuit protection circuit are all connected to the digital signal processor and control circuit. The overvoltage protection circuit and short-circuit protection circuit are all connected to the rectifier filter circuit, and the digital signal processor and control circuit are connected.

[0050] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A UPS DC bus overvoltage short circuit protection device, characterized in that, include: Digital signal processor; Control circuits responsible for monitoring and adjusting the operating status of the UPS power supply; A rectifier and filter circuit used to convert input AC power to DC power and filter out high-frequency interference and fluctuations in AC power; An overvoltage protection circuit used to automatically disconnect the power supply circuit when there is an overvoltage on the DC bus; A short-circuit protection circuit used to block the IGBT drive signal from the PWM controller and output a DC bus short-circuit signal to the digital signal processor when the DC bus is short-circuited. The rectifier filter circuit, overvoltage protection circuit, and short-circuit protection circuit are all connected to the digital signal processor and control circuit. The overvoltage protection circuit and short-circuit protection circuit are all connected to the rectifier filter circuit, and the digital signal processor and control circuit are connected.

2. The UPS DC bus overvoltage and short-circuit protection device according to claim 1, characterized in that: The rectifier and filter circuit includes terminal block X1, terminal block X2, terminal block X3, amplifier IC1, and amplifier IC2. An adjustable resistor RP1 is connected between pin 1 and pin 2 of terminal block X1, an adjustable resistor RP2 is connected between pin 2 and pin 3 of terminal block X1, a capacitor C1 is connected between pin 1 of amplifier IC1 and the adjustment terminal of adjustable resistor RP2, and a capacitor C4 is connected between pin 4 of amplifier IC1 and pin 1 of terminal block X2. A capacitor C6 is connected between pin 1 of amplifier IC2 and the adjustment terminal of adjustable resistor RP1, and a capacitor C9 is connected between pin 4 of amplifier IC2 and pin 4 of terminal block X2.

3. The UPS DC bus overvoltage and short-circuit protection device according to claim 2, characterized in that: A series-connected rectifier diode D1 and D2, and a series-connected rectifier diode D3 and D4 are connected in parallel between pins 1 and 2 of the terminal block X3. A capacitor C11 and a capacitor C12 are also connected in parallel between the terminals of rectifier diodes D1 and D2 and the terminals of rectifier diodes D3 and D4. The terminals of capacitors C11 and C12 are respectively connected to pin 1 of amplifier IC1 and pin 1 of amplifier IC2.

4. The UPS DC bus overvoltage and short-circuit protection device according to claim 1, characterized in that: The overvoltage protection circuit includes a chip U810, a transistor Q850, and a transformer T800. A resistor R811 is connected to pin 2 of the chip U810. A capacitor C811 is connected between pins 3 and 6 of the chip U810. Resistors R813 and R814 are connected in parallel between pins 4 and 6 of the chip U810. A resistor R812 is connected between pin 4 of the chip U810 and the collector of the transistor Q850. A diode D850 and a capacitor C850 and a resistor R850 are connected in parallel at pin 1 of the transformer T800. A resistor R851 and a capacitor C851 are connected between the diode D850 and pin 2 of the transformer T800. A resistor R852 is connected between the collector and emitter of the transistor Q850. A resistor R853 is connected between the base and collector of the transistor Q850.

5. A UPS DC bus overvoltage and short-circuit protection device according to claim 4, characterized in that: A MOSFET Q820 is connected to pin 6 of the transformer T800. The gate of the MOSFET Q820 is connected to pin 1 of the chip U810. A resistor R805 is connected to the source of the MOSFET Q820. A diode D830 is connected to pins 7 and 8 of the transformer T800. Capacitors C831 and C832 are connected in parallel between pin 2 of the diode D830 and pins 9 and 10 of the transformer T800.

6. A UPS DC bus overvoltage and short-circuit protection device according to claim 1, characterized in that: The short-circuit protection circuit includes a chip U10 and a transistor Q5. A resistor R28 is connected between pin 1 and pin 4 of the chip U10. A resistor R36 is connected between the collector of the transistor Q5 and pin 4 of the chip U10. A resistor R33 is connected between the terminals of pins 1, 2, and 3 of the chip U10 and the terminals of pins 5, 6, 7, and 8. An inductor L1 and a diode D11 are connected between pins 5 and 8 of the chip U10.

7. A UPS DC bus overvoltage and short-circuit protection device according to claim 6, characterized in that: The base of transistor Q5 is connected to resistor R34, diode D10, and resistor R35. One end of diode D10 is connected to resistor R29 and resistor R30. Capacitor C21 is connected between the emitter of transistor Q5 and pin 1 of chip U10.

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