A 3KVA standby UPS main power circuit

Abstract

This utility model relates to the field of power supply technology and provides a 3KVA standby UPS main power circuit, including an AC filter / bypass input circuit, an AC voltage regulator / conversion circuit, a DC-DC converter circuit, an inverter circuit, an AC bypass / inverter conversion circuit, and an output protection circuit. The AC filter / bypass input circuit is electrically connected to the AC voltage regulator / conversion circuit; the DC-DC converter circuit is electrically connected to the inverter circuit; both the AC voltage regulator / conversion circuit and the inverter circuit are electrically connected to the AC bypass / inverter conversion circuit; and the AC bypass / inverter conversion circuit is electrically connected to the output protection circuit. This utility model achieves rapid and seamless switching between mains and inverter power supply modes, continuously and stably outputs standard AC voltage, and has comprehensive overvoltage, overcurrent, and lightning protection, thereby significantly improving power supply reliability and output AC power quality.

Description

Technical Field

[0001] This utility model relates to the field of power supply technology, and in particular to a 3KVA standby UPS main power circuit. Background Technology

[0002] In modern information society, uninterruptible power supplies (UPS) are widely used in critical fields such as data centers, communication base stations, financial institutions, and medical equipment. They have become core equipment for ensuring the continuity and stability of power supply, and technological iterations have significantly improved the reliability of power supply. When a UPS is operating, it mainly provides stable power output to the load under normal power supply conditions through bypass power supply and inverter power supply modes. It switches to backup power mode when the power grid is abnormal. However, in actual application scenarios, the environment is often particularly complex. Due to the inherent technical limitations of traditional UPS power supplies in voltage stability control, the UPS's voltage regulation capability drops sharply when encountering power grid voltage fluctuations or sudden load changes. This often leads to a decline in the UPS's output voltage quality and power supply performance, preventing it from fully realizing its functions.

[0003] Chinese patent CN118713277A discloses a UPS power management module and method, which implements basic power management and backup power supply functions through a constant power supply electronic module, an AC output unit, a main control unit, and a backup battery sub-module. However, this device lacks an effective AC voltage regulation control circuit, and its single power management method cannot cope with complex power grid environment changes, exhibiting weak resistance to voltage fluctuations. Because this device primarily focuses on power management and switching control, lacking a dedicated AC voltage regulation and conversion circuit design, it cannot provide a stable 220V standard voltage output when the mains voltage is unstable, resulting in a technical defect of low output voltage quality and failing to meet the power supply needs of precision equipment with high voltage stability requirements. Utility Model Content

[0004] In view of this, this utility model proposes a 3KVA standby UPS main power circuit to solve the problem that the existing technology mainly focuses on power management and switching control, lacks a dedicated AC voltage regulation and conversion circuit design, which leads to the inability to provide a stable 220V standard voltage output when the mains voltage is unstable, resulting in poor output voltage quality and failing to meet the power supply needs of precision equipment with high voltage stability requirements.

[0005] The technical solution of this utility model is implemented as follows: A 3KVA standby UPS main power circuit is provided, comprising an AC filter / bypass input circuit, an AC voltage regulator / conversion circuit, a DC-DC converter circuit, an inverter circuit, an AC bypass / inverter conversion circuit, and an output protection circuit, wherein:

[0006] The AC filter / bypass access circuit is electrically connected to the AC voltage regulator / conversion circuit, the DC-DC converter circuit is electrically connected to the inverter circuit, both the AC voltage regulator / conversion circuit and the inverter circuit are electrically connected to the AC bypass / inverter conversion circuit, and the AC bypass / inverter conversion circuit is electrically connected to the output protection circuit.

[0007] Based on the above technical solutions, preferably, the AC filtering / bypass access circuit includes capacitors C1-C6, inductor L1, fuse F1, varistor MOV1, varistor MOV2, and relay RY1.

[0008] Based on the above technical solution, preferably, pin 1 of inductor L1 is electrically connected to one end of capacitor C3, one end of capacitor C1, one end of varistor MOV1, and one end of fuse F1, respectively; pin 2 of inductor L1 is electrically connected to one end of varistor MOV2, one end of capacitor C4, one end of capacitor C6, and pin 3 of relay RY1, respectively; pin 3 of inductor L1 is electrically connected to the other end of capacitor C1, one end of capacitor C2, and the other end of varistor MOV1, respectively; pin 4 of inductor L1 is electrically connected to the other end of varistor MOV2, one end of capacitor C5, the other end of capacitor C4, and pin 1 of relay RY1, respectively; and the other ends of capacitors C2, C3, C5, and C6 are all grounded.

[0009] Based on the above technical solutions, preferably, the AC voltage regulator / conversion circuit includes resistors R1-R3, capacitor C7, Zener diodes ZD1, ZD2, and ZD3, transistors Q1-Q3, relays RY2, RY3, and RY4, and transformer T2.

[0010] Based on the above technical solution, preferably, the base of transistor Q1 is electrically connected to one end of resistor R1, the collector of transistor Q1 is electrically connected to the negative terminal of Zener diode ZD1 and pin 1 of relay RY2, and the emitter of transistor Q1 and the positive terminal of Zener diode ZD1 are both grounded. The base of transistor Q2 is electrically connected to one end of resistor R2, and the collector of transistor Q2 is electrically connected to the negative terminal of Zener diode ZD2 and pin 8 of relay RY3, respectively. The emitter of transistor Q2 and the positive terminal of Zener diode ZD2 are both grounded. The base of transistor Q3 is electrically connected to one end of resistor R3, and the collector of transistor Q3 is electrically connected to the negative terminal of Zener diode ZD3 and pin 8 of relay RY3, respectively. Pin 5 of electrical appliance RY4 is electrically connected. The emitter of transistor Q3 and the positive terminal of Zener diode ZD3 are both grounded. Pins 3 and 6 of relay RY2, pins 3 and 6 of relay RY3, and one end of capacitor C7 are all electrically connected to pin 1 of transformer T2. The other end of capacitor C7 is electrically connected to pin 3 of relay RY4. Pins 4 and 5 of relay RY2 are electrically connected to pin 5 of transformer T2. Pins 4 and 5 of relay RY3 are electrically connected to pin 3 of transformer T2. Pin 4 of relay RY4 is electrically connected to pin 2 of transformer T2. Pins 1 of relays RY2, RY3, and RY4 are all connected to a +12V power supply.

[0011] Based on the above technical solutions, preferably, the DC-DC conversion circuit includes resistors R11-R35, capacitors C10-C17, fuses F2-F3, diodes D1-D5, MOSFETs Q6-Q17, inductor L2, and transformer T1.

[0012] Based on the above technical solutions, preferably, the inverter circuit includes resistors R36-R59, capacitor C18, and MOSFETs Q18-Q29.

[0013] Based on the above technical solutions, preferably, the AC bypass / inverter conversion circuit includes resistors R4-R6, capacitors C8-C9, Zener diode ZD4, transistor Q4, thermistor NTC1, thermistor NTC2, relay RY5, and relay RY6.

[0014] Based on the above technical solution, preferably, pin 8 of relay RY5 is electrically connected to the positive terminal of capacitor C8 and one end of resistor R4, the other end of resistor R4 is electrically connected to the +24VP power supply, the negative terminal of capacitor C8 is grounded, pins 3 and 6 of relay RY5 are both electrically connected to one end of thermistor NTC1, pin 1 of relay RY5 is electrically connected to the negative terminal of Zener diode ZD4, the collector of transistor Q4, and pin 1 of relay RY6, the emitter of transistor Q4 and the positive terminal of Zener diode ZD4 are both grounded, the base of transistor Q4 is electrically connected to one end of resistor R6, pin 8 of relay RY6 is electrically connected to the positive terminal of capacitor C9 and one end of resistor R5, the other end of resistor R5 is electrically connected to the +24VP power supply, the negative terminal of capacitor C9 is grounded, and pins 3 and 6 of relay RY6 are both electrically connected to one end of thermistor NTC2.

[0015] Based on the above technical solutions, preferably, the output protection circuit includes resistors R7-R10, Zener diodes ZD5, ZD6, and ZD7, transistor Q5, current transformer CT1, surge protection module FL, and relay RY7.

[0016] The 3KVA standby UPS main power circuit provided by this utility model has the following advantages compared with the prior art:

[0017] (1) By organically integrating and electrically connecting circuits such as AC filtering / bypass access, AC voltage regulation / conversion, DC-DC conversion, inverter, AC bypass / inverter conversion and output protection, it realizes fast and seamless switching between the two power supply modes of mains power and inverter, continuously and stably outputs standard AC voltage and has complete overvoltage, overcurrent and lightning protection, thereby significantly improving power supply reliability and output AC power quality.

[0018] (2) By using capacitors and inductors to form a multi-stage LC filter network, combined with varistor MOV1 and varistor MOV2 to quickly clamp the surge voltage, and using fuse F1 for overcurrent protection, high-efficiency high-frequency filtering and transient overvoltage suppression of input AC power are achieved. At the same time, through the coordinated layout of relay RY1 and capacitor array, the impact of grid-side conducted interference on the downstream circuit is reduced, thereby ensuring that the main power circuit has stronger anti-interference capability and input protection reliability in complex grid environment. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the system structure of the main power circuit of a 3KVA standby UPS power supply according to the present invention.

[0021] Figure 2 This is a circuit wiring diagram of the main power circuit of a 3KVA standby UPS power supply according to this utility model. Detailed Implementation

[0022] The technical solutions of this utility model will be clearly and completely described below with reference to the embodiments of this utility model. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this utility model.

[0023] Please see Figure 1 This utility model provides a 3KVA standby UPS main power circuit, which includes an AC filter / bypass input circuit, an AC voltage regulator / conversion circuit, a DC-DC converter circuit, an inverter circuit, an AC bypass / inverter conversion circuit, and an output protection circuit, wherein:

[0024] The AC filter / bypass access circuit is electrically connected to the AC voltage regulator / conversion circuit, the DC-DC converter circuit is electrically connected to the inverter circuit, both the AC voltage regulator / conversion circuit and the inverter circuit are electrically connected to the AC bypass / inverter conversion circuit, and the AC bypass / inverter conversion circuit is electrically connected to the output protection circuit.

[0025] Specifically, this embodiment organically integrates and electrically connects circuits such as AC filtering and bypass access, AC voltage regulation and conversion, DC-DC conversion, inverter, AC bypass and inverter conversion, and output protection, thereby achieving rapid and seamless switching between the two power supply modes of mains power and inverter, continuously and stably outputting standard AC voltage, and having complete overvoltage, overcurrent and lightning protection, thus significantly improving power supply reliability and output AC power quality.

[0026] The main power circuit of the 3KVA standby UPS power supply in this embodiment consists of an AC filter / bypass access circuit, an AC voltage regulator / conversion circuit, a DC-DC converter circuit, an inverter circuit, an AC bypass / inverter conversion circuit, and an output protection circuit.

[0027] In one specific embodiment, the main power circuit of the 3KVA standby UPS power supply operates as follows: When the external AC power is normal, the AC bypass outputs the 220V AC power required by the user equipment, while the DC charging power supply charges the battery; when the AC input voltage is too high (240V) or too low (190V), the AC voltage regulator / conversion circuit relay switches to the AC voltage regulator transformer to transform the voltage to 220V before output. When the external AC power fails, the battery is connected to the DC-DC converter circuit for DC-DC conversion, then inverted by the inverter circuit and chopped at high frequency, then the AC bypass / inverter conversion circuit selects the output mode, and finally the output protection circuit outputs the 220V AC power required by the user equipment. The entire circuit's operation is intelligently detected and precisely controlled by a microcontroller.

[0028] Please see Figure 2 The AC filter / bypass circuit includes capacitors C1-C6, inductor L1, fuse F1, varistor MOV1, varistor MOV2, and relay RY1.

[0029] Pin 1 of inductor L1 is electrically connected to one end of capacitor C3, one end of capacitor C1, one end of varistor MOV1, and one end of fuse F1. Pin 2 of inductor L1 is electrically connected to one end of varistor MOV2, one end of capacitor C4, one end of capacitor C6, and pin 3 of relay RY1. Pin 3 of inductor L1 is electrically connected to the other end of capacitor C1, one end of capacitor C2, and the other end of varistor MOV1. Pin 4 of inductor L1 is electrically connected to the other end of varistor MOV2, one end of capacitor C5, the other end of capacitor C4, and pin 1 of relay RY1. The other ends of capacitors C2, C3, C5, and C6 are all grounded.

[0030] Specifically, in this embodiment, varistor MOV1 and varistor MOV2 form a live-to-neutral lightning protection circuit, effectively protecting the UPS power supply from high-voltage surges from external power grid lightning. Common-mode filter L1, capacitors C2, C3, C5, and C6 form a common-mode filter circuit, while capacitors C1 and C4 form a differential-mode filter circuit, which can effectively suppress external power grid EMI and high-frequency noise interference generated inside the power supply.

[0031] The working principle of the AC filter / bypass access circuit in this embodiment is as follows: When external AC power is supplied, relay RY1 is connected, and the AC bypass is connected. When external AC power fails, relay RY1 is turned off, and the battery is connected.

[0032] Please see Figure 2 The AC voltage regulator / conversion circuit includes resistors R1-R3, capacitor C7, Zener diodes ZD1, ZD2, and ZD3, transistors Q1-Q3, relays RY2, RY3, and RY4, and transformer T2.

[0033] The base of transistor Q1 is electrically connected to one end of resistor R1. The collector of transistor Q1 is electrically connected to the cathode of Zener diode ZD1 and pin 1 of relay RY2. The emitter of transistor Q1 and the anode of Zener diode ZD1 are both grounded. The base of transistor Q2 is electrically connected to one end of resistor R2. The collector of transistor Q2 is electrically connected to the cathode of Zener diode ZD2 and pin 8 of relay RY3. The emitter of transistor Q2 and the anode of Zener diode ZD2 are both grounded. The base of transistor Q3 is electrically connected to one end of resistor R3. The collector of transistor Q3 is electrically connected to the cathode of Zener diode ZD3 and pin 5 of relay RY4. Electrical connections: The emitter of transistor Q3 and the anode of Zener diode ZD3 are both grounded. Pins 3 and 6 of relay RY2, pins 3 and 6 of relay RY3, and one end of capacitor C7 are all electrically connected to pin 1 of transformer T2. The other end of capacitor C7 is electrically connected to pin 3 of relay RY4. Pins 4 and 5 of relay RY2 are electrically connected to pin 5 of transformer T2. Pins 4 and 5 of relay RY3 are electrically connected to pin 3 of transformer T2. Pin 4 of relay RY4 is electrically connected to pin 2 of transformer T2. Pins 1 of relays RY2, RY3, and RY4 are simultaneously connected to the +12Vp power supply.

[0034] Specifically, the working principle of the AC voltage regulator / conversion circuit in this embodiment is as follows: when the external AC power is normal, the AC bypass outputs the 220V AC power required by the user equipment; when the external AC input voltage is too high to 240V or too low to 190V, the AC bypass switches to the AC voltage regulator transformer T2 through relays RY2, RY3, and RY4 to transform the voltage to 220V before outputting.

[0035] Please see Figure 2 The DC-DC converter circuit includes resistors R11-R35, capacitors C10-C17, fuses F2-F3, diodes D1-D5, MOSFETs Q6-Q17, inductor L2, and transformer T1.

[0036] The gate of MOSFET Q6 is electrically connected to one end of resistor R11 and one end of resistor R12, respectively. The gate of MOSFET Q7 is electrically connected to one end of resistor R13 and one end of resistor R14, respectively. The gate of MOSFET Q8 is electrically connected to one end of resistor R15 and one end of resistor R16, respectively. The gate of MOSFET Q9 is electrically connected to one end of resistor R17 and one end of resistor R18, respectively. The gate of MOSFET Q10 is electrically connected to one end of resistor R19 and one end of resistor R20, respectively. The gate of MOSFET Q11 is electrically connected to one end of resistor R21 and one end of resistor R22, respectively. The other end of resistor R12, the source of MOSFET Q6, and... The other end of resistor R14, the source of MOSFET Q7, the other end of resistor R16, the source of MOSFET Q8, the other end of resistor R18, the source of MOSFET Q9, the other end of resistor R20, the source of MOSFET Q10, the other end of resistor R22, and the source of MOSFET Q11 are all electrically connected to pin 1 of transformer T1. The other ends of resistors R11, R13, R15, R17, and R19 are all electrically connected to the other end of resistor R21. The drains of MOSFETs Q6, Q7, Q8, and Q9 are... The drains of MOSFETs Q10 and Q11, the positive terminals of capacitors C10 and C11, and one end of fuse F2 are all electrically connected to one end of fuse F3. The other end of fuse F2 is electrically connected to the other end of fuse F3. The gates of MOSFETs Q12 and Q13 are electrically connected to one end of resistors R23 and R24, respectively. The gates of MOSFETs Q13 and Q14 are electrically connected to one end of resistors R25 and R26, respectively. The gates of MOSFETs Q14 and Q15 are electrically connected to one end of resistors R27 and R28, respectively. The gates of MOSFETs Q15 and Q15 are electrically connected to one end of resistors R29 and R30, respectively. The gate of ET transistor Q16 is electrically connected to one end of resistor R31 and one end of resistor R32, respectively. The gate of MOSFET Q17 is electrically connected to one end of resistor R33 and one end of resistor R34, respectively. The other end of resistor R24, the source of MOSFET Q12, the other end of resistor R26, the source of MOSFET Q13, the other end of resistor R28, the source of MOSFET Q14, the other end of resistor R30, the source of MOSFET Q15, the other end of resistor R32, the source of MOSFET Q16, the other end of resistor R34, the source of MOSFET Q17, the negative terminals of capacitors C11 and C10 are all electrically connected to the ground terminal of GNDP.The other ends of resistors R23, R25, R27, R29, and R31 are all electrically connected to the other end of resistor R33. The drains of MOSFETs Q12, Q13, Q14, Q15, Q16, and Q17 are all electrically connected to pin 2 of transformer T1. Pin 3 of transformer T1 is electrically connected to one end of capacitor C12, the anode of diode D1, one end of capacitor C13, and the cathode of diode D2, respectively. Pin 4 of transformer T1 is electrically connected to diode D1, the cathode of diode D2, and the cathode of diode D1, respectively. The negative terminal of diode D4, one end of capacitor C15, the positive terminal of diode D3, and one end of capacitor C14 are electrically connected. The other end of capacitor C12 is electrically connected to the negative terminal of diode D1, one end of resistor R35, one end of capacitor C16, one end of inductor L2, the other end of capacitor C14, and the negative terminal of diode D3. The positive terminal of diode D4, the other end of capacitor C15, the positive terminal of diode D2, and the other end of capacitor C13 are all electrically connected to the ground terminal of GNDP. The other end of resistor R35 is electrically connected to the other end of capacitor C16, the positive terminal of diode D5, and one end of capacitor C17. The other end of capacitor C17 is electrically connected to the negative terminal of diode D5 and the other end of inductor L2.

[0037] Specifically, the DC-DC converter circuit in this embodiment includes inductor L2, diodes D1, D2, D3, D4, MOSFETs Q6, Q7, Q8, Q9, Q10, Q11, Q12, Q13, Q14, Q15, Q16, Q17, and transformer T1, which are used to convert the 48V battery voltage signal into 300V high-voltage pulsating DC power.

[0038] The MOSFETs Q6, Q7, Q8, Q9, Q10, Q11, Q12, Q13, Q14, Q15, Q16, and Q17, together with the primary winding of transformer T1, form the primary full-wave rectifier circuit. The inductor L2, diodes D1, D2, D3, and D4, together with the secondary winding of transformer T1, form the secondary full-bridge rectifier boost circuit. Resistors R35, capacitors C12, C13, C14, C15, C16, and C17, and diode D5 form a noise absorption circuit.

[0039] Please see Figure 2 The inverter circuit includes resistors R36-R59, capacitor C18, and MOSFETs Q18-Q29.

[0040] The gates of MOSFET Q18 and Q20 are electrically connected to one end of resistors R36 and R37, respectively. The gates of MOSFET Q19 and Q20 are electrically connected to one end of resistors R38 and R39, respectively. The gates of MOSFET Q20 and Q20 are electrically connected to one end of resistors R40 and R41, respectively. The gates of MOSFET Q21 and Q20 are electrically connected to one end of resistors R42 and R43, respectively. The gates of MOSFET Q22 and Q20 are electrically connected to one end of resistors R44 and R45, respectively. The gates of MOSFET Q23 and Q24 are electrically connected to one end of resistors R46 and R47, respectively. One end of resistor R49 is electrically connected to the gate of MOSFET Q25, which is electrically connected to one end of resistors R50 and R51 respectively. The gate of MOSFET Q26 is electrically connected to one end of resistors R52 and R53 respectively. The gate of MOSFET Q27 is electrically connected to one end of resistors R54 and R55 respectively. The gate of MOSFET Q28 is electrically connected to one end of resistors R56 and R57 respectively. The gate of MOSFET Q29 is electrically connected to one end of resistors R58 and R59 respectively. The other end of resistor R36 is electrically connected to the other end of resistors R38 and R40 respectively. The other end of resistor R42 is electrically connected to... The other end of resistor R44 is electrically connected to the other end of resistor R46. The other end of resistor R48 is electrically connected to the other ends of resistors R50 and R52, respectively. The other end of resistor R54 is electrically connected to the other ends of resistors R56 and R58, respectively. The other end of resistor R37, the source of MOSFET Q18, the drain of MOSFET Q24, the other end of resistor R39, the source of MOSFET Q19, the drain of MOSFET Q25, the other end of resistor R41, the source of MOSFET Q20, and the drain of MOSFET Q26 are all electrically connected. The other end of resistor R43, the source of MOSFET Q21, and the drain of MOSFET Q27 are all electrically connected. The other end of resistor R45, the source of MOSFET Q22, the drain of MOSFET Q28, the other end of resistor R47, and the source of MOSFET Q23 are all electrically connected to the drain of MOSFET Q29. The other end of resistor R49, the source of MOSFET Q24, the other end of resistor R51, the source of MOSFET Q25, the other end of resistor R53, the source of MOSFET Q26, the other end of resistor R55, the source of MOSFET Q27, the other end of resistor R57, the source of MOSFET Q28, the other end of resistor R59, the source of MOSFET Q29, and one end of capacitor C18 are all electrically connected to the ground terminal of GNDP.The drains of MOSFETs Q18, Q19, Q20, Q21, Q22, and Q23 are all electrically connected to the other end of capacitor C18.

[0041] The inverter circuit in this embodiment consists of MOSFETs Q18, Q19, Q20, Q21, Q22, Q23, Q24, Q25, Q26, Q27, Q28, and Q29. After high-frequency chopping, the 300V high-voltage pulsating DC output from the DC-DC converter circuit is transformed into high-quality AC. Capacitor C18 and inductor L2 form an LC filter circuit, which filters out high-frequency noise from the output.

[0042] Please see Figure 2 The AC bypass / inverter conversion circuit includes resistors R4-R6, capacitors C8-C9, Zener diode ZD4, transistor Q4, thermistor NTC1, thermistor NTC2, relay RY5, and relay RY6.

[0043] Pin 8 of relay RY5 is electrically connected to the positive terminal of capacitor C8 and one end of resistor R4, respectively. The other end of resistor R4 is electrically connected to the +24Vp power supply. The negative terminal of capacitor C8 is grounded. Pins 3 and 6 of relay RY5 are both electrically connected to one end of thermistor NTC1. Pin 1 of relay RY5 is electrically connected to the negative terminal of Zener diode ZD4, the collector of transistor Q4, and pin 1 of relay RY6, respectively. The emitter of transistor Q4 and the positive terminal of Zener diode ZD4 are both grounded. The base of transistor Q4 is electrically connected to one end of resistor R6. Pin 8 of relay RY6 is electrically connected to the positive terminal of capacitor C9 and one end of resistor R5, respectively. The other end of resistor R5 is electrically connected to the +24Vp power supply. The negative terminal of capacitor C9 is grounded. Pins 3 and 6 of relay RY6 are both electrically connected to one end of thermistor NTC2.

[0044] Specifically, the working principle of the AC bypass / inverter conversion circuit in this embodiment is as follows: when external AC power is supplied, relays RY5 and RY6 are connected to the AC bypass output to the user load; when external AC power fails, relays RY5 and RY6 are connected to the inverter circuit output to the user load, ensuring continuous power supply for a long time. Thermistors NTC1 and NTC2 serve as overcurrent protection for the inverter circuit output.

[0045] Please see Figure 2 The output protection circuit includes resistors R7-R10, Zener diodes ZD5, ZD6, and ZD7, transistor Q5, current transformer CT1, surge protection module FL, and relay RY7.

[0046] The negative terminal of Zener diode ZD6 is electrically connected to one end of resistor R8. The other end of resistor R8 is electrically connected to one end of resistor R9, one end of resistor R10, and pin 4 of transformer CT1. The positive terminal of Zener diode ZD6 is electrically connected to the positive terminal of Zener diode ZD7. The negative terminal of Zener diode ZD7, the other end of resistor R9, the other end of resistor R10, and pin 3 of transformer CT1 are all electrically connected to the GNDP ground terminal. Pin 1 of relay RY7 is electrically connected to the negative terminal of Zener diode ZD5 and the collector of transistor Q5. The base of transistor Q5 is electrically connected to one end of resistor R7. The emitter of transistor Q5 and the positive terminal of Zener diode ZD5 are both electrically connected to the GNDP ground terminal. Pins 2, 3, 6, and 7 of relay RY7 are all electrically connected to the live wire of surge protection module FL. Pins 4 and 5 of relay RY7 are electrically connected to pin 2 of transformer CT1. Pin 8 of relay RY7 is electrically connected to the +12VP power supply.

[0047] Specifically, in this embodiment, the output protection circuit shuts off the output relay RY7 to protect the downstream user load when the UPS power supply outputs overvoltage or overcurrent. The current transformer CT1 detects the output current. The surge protection module FL effectively protects the user load from high-voltage surges from external power grid lightning.

[0048] Specifically, in this embodiment, the main power circuit of the 3KVA standby UPS power supply automatically switches and stabilizes the input AC voltage when it is too high or too low, and then outputs the 220V high-quality AC power required by the user equipment, thereby realizing the function of automatic AC voltage stabilization of the standby UPS power supply.

[0049] The DC-DC converter circuit uses primary full-wave rectification and secondary full-bridge rectification to boost the voltage, converting the 48V battery voltage signal into 300V high-voltage pulsating DC power. The entire circuit topology is simple in design and achieves a balanced performance.

[0050] Employing a classic full-bridge inverter circuit, the 300V high-voltage pulsating DC power is converted into high-quality AC power through high-frequency inverter chopping, meeting the power supply requirements of critical equipment. This reduces circuit power consumption and improves operating efficiency.

[0051] The system achieves continuous power supply over extended periods by automatically switching between AC bypass and inverter output. The output protection circuit shuts off the downstream user load in case of overvoltage or overcurrent, ensuring safety and reliability.

[0052] The entire circuit features a classic full-bridge inverter chopper topology, automatic voltage regulation, high-quality AC output, long continuous power supply time, output overvoltage and overcurrent protection, and high reliability.

[0053] In this embodiment, the inverter circuit of the standby UPS power supply is normally inactive, while the AC bypass is engaged. The inverter circuit only operates when the input AC power fails or malfunctions. Since the external AC grid voltage can be unstable, frequently exceeding 240V or falling as low as 190V, a voltage regulator circuit is required to stabilize the output at 220V, providing a stable effective AC voltage to the downstream user loads. 3KVA uninterruptible power supplies (UPSs) are typically used in computer rooms to power critical equipment such as computers. Because these critical devices require high-quality AC power, long continuous power supply times, and overvoltage and overcurrent protection, and because these devices are numerous and widely distributed, multiple small-to-medium power supplies are needed for distributed power supply without mutual interference. Since UPSs require AC voltage regulation, independent modularity, and overvoltage and overcurrent protection, ordinary standby UPS circuits cannot solve these problems. However, the main power circuit of the 3KVA standby UPS power supply in this embodiment meets these requirements and can be widely applied in actual UPS module circuits.

[0054] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A 3KVA standby UPS main power circuit, characterized in that, The 3KVA standby UPS main power circuit includes an AC filter / bypass input circuit, an AC voltage regulator / conversion circuit, a DC-DC converter circuit, an inverter circuit, an AC bypass / inverter conversion circuit, and an output protection circuit, wherein: The AC filter / bypass access circuit is electrically connected to the AC voltage regulator / conversion circuit, the DC-DC converter circuit is electrically connected to the inverter circuit, both the AC voltage regulator / conversion circuit and the inverter circuit are electrically connected to the AC bypass / inverter conversion circuit, and the AC bypass / inverter conversion circuit is electrically connected to the output protection circuit.

2. The main power circuit of a 3KVA standby UPS power supply as described in claim 1, characterized in that, The AC filter / bypass circuit includes capacitors C1-C6, inductor L1, fuse F1, varistor MOV1, varistor MOV2, and relay RY1.

3. The main power circuit of a 3KVA standby UPS power supply as described in claim 2, characterized in that, Pin 1 of inductor L1 is electrically connected to one end of capacitor C3, one end of capacitor C1, one end of varistor MOV1, and one end of fuse F1. Pin 2 of inductor L1 is electrically connected to one end of varistor MOV2, one end of capacitor C4, one end of capacitor C6, and pin 3 of relay RY1. Pin 3 of inductor L1 is electrically connected to the other end of capacitor C1, one end of capacitor C2, and the other end of varistor MOV1. Pin 4 of inductor L1 is electrically connected to the other end of varistor MOV2, one end of capacitor C5, the other end of capacitor C4, and pin 1 of relay RY1. The other ends of capacitors C2, C3, C5, and C6 are all grounded.

4. The main power circuit of a 3KVA standby UPS power supply as described in claim 1, characterized in that, The AC voltage regulator / conversion circuit includes resistors R1-R3, capacitor C7, Zener diodes ZD1, ZD2, and ZD3, transistors Q1-Q3, relays RY2, RY3, and RY4, and transformer T2.

5. The main power circuit of a 3KVA standby UPS power supply as described in claim 4, characterized in that, The base of transistor Q1 is electrically connected to one end of resistor R1. The collector of transistor Q1 is electrically connected to the cathode of Zener diode ZD1 and pin 1 of relay RY2. The emitter of transistor Q1 and the anode of Zener diode ZD1 are both grounded. The base of transistor Q2 is electrically connected to one end of resistor R2. The collector of transistor Q2 is electrically connected to the cathode of Zener diode ZD2 and pin 8 of relay RY3. The emitter of transistor Q2 and the anode of Zener diode ZD2 are both grounded. The base of transistor Q3 is electrically connected to one end of resistor R3. The collector of transistor Q3 is electrically connected to the cathode of Zener diode ZD3 and pin 8 of relay RY4.

5. Electrical connections: The emitter of transistor Q3 and the anode of Zener diode ZD3 are both grounded. Pins 3 and 6 of relay RY2, pins 3 and 6 of relay RY3, and one end of capacitor C7 are all electrically connected to pin 1 of transformer T2. The other end of capacitor C7 is electrically connected to pin 3 of relay RY4. Pins 4 and 5 of relay RY2 are electrically connected to pin 5 of transformer T2. Pins 4 and 5 of relay RY3 are electrically connected to pin 3 of transformer T2. Pin 4 of relay RY4 is electrically connected to pin 2 of transformer T2. Pins 1 of relays RY2, RY3, and RY4 are all connected to a +12V power supply.

6. The main power circuit of a 3KVA standby UPS power supply as described in claim 1, characterized in that, The DC-DC converter circuit includes resistors R11-R35, capacitors C10-C17, fuses F2-F3, diodes D1-D5, MOSFETs Q6-Q17, inductor L2, and transformer T1.

7. The main power circuit of a 3KVA standby UPS power supply as described in claim 1, characterized in that, The inverter circuit includes resistors R36-R59, capacitor C18, and MOSFETs Q18-Q29.

8. The main power circuit of a 3KVA standby UPS power supply as described in claim 1, characterized in that, The AC bypass / inverter conversion circuit includes resistors R4-R6, capacitors C8-C9, Zener diode ZD4, transistor Q4, thermistor NTC1, thermistor NTC2, relay RY5, and relay RY6.

9. The main power circuit of a 3KVA standby UPS power supply as described in claim 8, characterized in that, Pin 8 of relay RY5 is electrically connected to the positive terminal of capacitor C8 and one end of resistor R4, respectively. The other end of resistor R4 is electrically connected to the +24Vp power supply. The negative terminal of capacitor C8 is grounded. Pins 3 and 6 of relay RY5 are both electrically connected to one end of thermistor NTC1. Pin 1 of relay RY5 is electrically connected to the negative terminal of Zener diode ZD4, the collector of transistor Q4, and pin 1 of relay RY6, respectively. The emitter of transistor Q4 and the positive terminal of Zener diode ZD4 are both grounded. The base of transistor Q4 is electrically connected to one end of resistor R6. Pin 8 of relay RY6 is electrically connected to the positive terminal of capacitor C9 and one end of resistor R5, respectively. The other end of resistor R5 is electrically connected to the +24Vp power supply. The negative terminal of capacitor C9 is grounded. Pins 3 and 6 of relay RY6 are both electrically connected to one end of thermistor NTC2.

10. The main power circuit of a 3KVA standby UPS power supply as described in claim 1, characterized in that, The output protection circuit includes resistors R7-R10, Zener diodes ZD5, ZD6, and ZD7, transistor Q5, current transformer CT1, surge protection module FL, and relay RY7.

Images