Topological structure with zero-ground voltage of UPS (Uninterrupted Power Supply)

Abstract

The utility model discloses a topological structure with zero-ground voltage of a UPS (Uninterrupted Power Supply). Comprising a storage battery pack, an inverter connected with the storage battery pack, a rectifier used for converting input alternating current into direct current, an isolation transformer used for electrical isolation, a filter circuit used for reducing interference signals generated by a power grid side and the isolation transformer, and a control circuit. According to the utility model, interference signals generated by a power grid side and the isolation transformer are reduced by using the filter circuit, the quality of electric energy is improved, the input filter unit filters input current from a power grid, and interference components such as higher harmonics in the input current are removed; the output filtering unit filters the alternating current converted by the inverter to further purify the electric energy, an electrical system of the input end and an electrical system of the output end are isolated through the isolation transformer, electrical interference is prevented from being transmitted to load equipment through a power grid, and the output circuit with reverse voltage transmission prevention protection is utilized to effectively prevent reverse voltage transmission. And the stability of electric energy output of load equipment is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of uninterruptible power supply, in particular to a topological structure of a UPS with zero neutral-ground voltage. Background Art

[0002] The neutral-ground voltage of an uninterruptible power supply (UPS) refers to the voltage difference between the neutral line and the ground line. Ideally, the neutral-ground voltage should be zero, but in practice, due to various factors, the neutral-ground voltage cannot be completely eliminated.

[0003] At present, in order to make the neutral-ground voltage of UPS approach zero, an isolation transformer is usually added to the load end of UPS, and the isolated neutral line is grounded. The isolated neutral line grounding can ensure that the neutral-ground voltage of the load approaches zero.

[0004] However, although the isolation transformer can block direct electrical connection, it cannot completely eliminate electromagnetic interference. In some cases, the isolation transformer may become a propagation path for electromagnetic interference, causing interference at the load end, thereby affecting the stability of the power output to the load equipment. Therefore, we need to propose a UPS topology with zero neutral-ground voltage to solve the above-mentioned problems. This can not only make the neutral-ground voltage of the UPS zero, but also improve the stability of the power output to the load equipment. Utility Model Content

[0005] The purpose of the present utility model is to provide a topological structure in which the neutral-to-ground voltage of a UPS is zero. By cooperating with a filter circuit, an isolation transformer, an output circuit, and a static switch, the neutral-to-ground voltage of the UPS can be made zero while also improving the stability of the power output to the load equipment, thereby solving the problems raised in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solutions: a UPS topology with a zero neutral-ground voltage, comprising a battery pack, an inverter connected to the battery pack, a rectifier for converting input AC power into DC power, an isolation transformer for electrical isolation, a filter circuit for reducing interference signals generated by the grid side and the isolation transformer itself, and a control circuit;

[0007] The filtering circuit includes an input filtering unit and an output filtering unit, wherein the input filtering unit is connected to the input end of the isolation transformer, and the output filtering unit is connected to the output end of the isolation transformer;

[0008] One end of the battery pack is connected to an inverter, the output end of the inverter is connected to a static switch capable of automatically switching circuits, one end of the static switch is connected to a filter circuit, one end of the filter circuit is connected to an isolation transformer, and the other end of the isolation transformer is connected to an output circuit with anti-reverse voltage transmission protection;

[0009] The output end of the rectifier is connected to the battery pack and the static switch respectively, and the control circuit is connected to the inverter, the rectifier, the isolation transformer and the static switch respectively.

[0010] Preferably, the isolation transformer includes a transformer T1 and a driver chip for driving the transformer T1 to start. The input side of the transformer T1 is connected in parallel with a diode D1 and a diode D3 arranged in series, a diode D2 and a diode D4 arranged in series, and a capacitor C5 and a capacitor C6 arranged in series. The input side of the transformer T1 is connected to the driver chip through a transistor Q1, and the emitter end of the transistor Q1 is connected to a resistor R2, one end of the resistor R2 is connected to the connection end of the capacitor C6 and the diode D4, and the output end of the transformer T1 is provided with an output coil S1, an output coil S2, and an output coil S3.

[0011] Preferably, the input filter unit includes a capacitor C1, a capacitor C2, an inductor L1, an inductor L2, and a capacitor C3 and a capacitor C4 arranged in parallel, the connection ends of the diode D2 and the diode D4 are connected to a resistor R1, one end of the resistor R1 is connected to one end of the inductor L1, the capacitor C1 and the capacitor C2 are respectively connected to the two ends of the inductor L1, the inductor L2 is connected between the capacitor C1 and the capacitor C2, and the inductor L2 and the inductor L1 are respectively located at the two ends of the capacitor C1, the connection end of the capacitor C3 and the capacitor C4 is grounded, the other end of the capacitor C3 is connected to the connection end of the resistor R1 and the capacitor C2, and the other end of the capacitor C4 is connected to the connection end of the capacitor C2 and the inductor L2.

[0012] Preferably, the output filter unit includes a first filter component connected to the output coil S1, a second filter component connected to the output coil S2, and a third filter component connected to the output coil S3. The first filter component is mainly composed of a capacitor C7, an inductor L3, and a capacitor C12. The capacitor C7 and the capacitor C12 are connected in parallel to the output coil S1. The inductor L3 is connected between the capacitor C7 and the capacitor C12. The connecting end of the inductor L3 and the capacitor C7 is connected to a diode D7. The diode D7 is connected to one end of the output coil S1.

[0013] The second filter component is mainly composed of a capacitor C8, an inductor L4 and a capacitor C11. The capacitor C8 and the capacitor C11 are connected in parallel to the output coil S2. The inductor L4 is connected between the capacitor C8 and the capacitor C11. The connecting end of the inductor L4 and the capacitor C8 is connected to a diode D6. The diode D6 is connected to one end of the output coil S2.

[0014] The third filter component is mainly composed of a capacitor C9, an inductor L5 and a capacitor C10. The capacitor C9 and the capacitor C10 are connected in parallel to the output coil S3. The inductor L5 is connected between the capacitor C9 and the capacitor C10. The connecting end of the inductor L5 and the capacitor C9 is connected to a diode D5, and the diode D5 is connected to one end of the output coil S3.

[0015] Preferably, the static switch includes a coupling chip U3, a transmitting end of the coupling chip U3 is connected to a resistor R5 for receiving a control signal, one control end of the coupling chip U3 is connected to a thyristor Q11, one end of the thyristor Q11 is connected to the other control end of the coupling chip U3 through a resistor R6, a connection end between the thyristor Q11 and the coupling chip U3 is connected to a resistor R7, a capacitor C33 and a resistor R8 arranged in series are connected between the two control ends of the coupling chip U3, and the non-connected ends of the capacitor C33 and the resistor R8 are respectively connected to two ends of the thyristor Q11.

[0016] Preferably, the output circuit includes a voltage stabilizing chip U5, the input end of the voltage stabilizing chip U5 is connected to a ground capacitor C13, the output end of the voltage stabilizing chip U5 is connected to a ground capacitor C14, and a voltage stabilizing diode D8 is connected between the output and input ends of the voltage stabilizing chip U5.

[0017] Preferably, the control circuit includes a DSP processor for accurately monitoring the mains status, battery power and inverter working status, one end of the DSP processor is connected to a single-chip microcomputer, and the single-chip microcomputer and the DSP processor are both connected to the inverter, rectifier, isolation transformer and static switch.

[0018] Compared with the prior art, the beneficial effects of the present invention are:

[0019] 1. The utility model cooperates with the filter circuit, isolation transformer, output circuit and static switch to reduce the interference signals generated by the grid side and the isolation transformer itself by using the filter circuit, thereby improving the quality of electric energy. The input filter unit filters the input current from the grid to remove interference components such as high-order harmonics; the output filter unit filters the AC power converted by the inverter to further purify the electric energy. The electrical systems of the input and output ends are isolated by the isolation transformer to prevent electrical interference from being transmitted to the load equipment through the grid. At the same time, the output circuit with anti-reverse voltage transmission protection is used to further improve the stability of the electric energy output to the load equipment.

[0020] 2. This utility model uses a control circuit in conjunction with the inverter, rectifier, isolation transformer, and static switch to monitor parameters such as the mains power status, battery charge, and inverter operating status, and controls the operation of each component based on these parameters. For example, when the mains power fails, the control circuit activates the inverter, converting the battery pack's DC power into AC power to power the load. When the mains power returns, the control circuit controls the static switch to switch the load back to the mains power supply. The control circuit also monitors and adjusts the operating status of each component in real time to ensure stable system operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a system block diagram of the utility model;

[0022] Figure 2 This is the circuit diagram of the isolation transformer of the utility model;

[0023] Figure 3 This is a circuit diagram of the static switch of the utility model;

[0024] Figure 4 This is a circuit diagram of the output circuit of the utility model. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0026] See also Figure 1-4 The utility model provides a technical solution: a topological structure of a UPS with a zero neutral-ground voltage, comprising a battery pack, an inverter connected to the battery pack, a rectifier for converting input AC power into DC power, an isolation transformer for electrical isolation, a filter circuit for reducing interference signals generated by the grid side and the isolation transformer itself, and a control circuit; the filter circuit comprises an input filter unit and an output filter unit, the input filter unit being connected to the input end of the isolation transformer, and the output filter unit being connected to the output end of the isolation transformer;

[0027] One end of the battery pack is connected to an inverter, the output end of the inverter is connected to a static switch capable of automatically switching circuits, one end of the static switch is connected to a filter circuit, one end of the filter circuit is connected to an isolation transformer, and the other end of the isolation transformer is connected to an output circuit with anti-reverse voltage transmission protection; the output end of the rectifier is respectively connected to the battery pack and the static switch, and the control circuit is respectively connected to the inverter, rectifier, isolation transformer and static switch.

[0028] The filter circuit is used to reduce the interference signals generated by the grid side and the isolation transformer itself, thereby improving the quality of electric energy. The input filter unit filters the input current from the grid to remove interference components such as high-order harmonics; the output filter unit filters the AC power converted by the inverter to further purify the electric energy. The electrical systems at the input and output ends are isolated by the isolation transformer to prevent electrical interference from propagating to the load equipment through the grid. At the same time, the output circuit with anti-reverse voltage transmission protection is used to further improve the stability of the electric energy output to the load equipment.

[0029] The isolation transformer includes a transformer T1 and a driver chip for driving the transformer T1 to start. The input side of the transformer T1 is connected in parallel with a diode D1 and a diode D3 arranged in series, a diode D2 and a diode D4 arranged in series, and a capacitor C5 and a capacitor C6 arranged in series. The input side of the transformer T1 is connected to the driver chip through a transistor Q1. The emitter end of the transistor Q1 is connected to a resistor R2, and one end of the resistor R2 is connected to the connection end of the capacitor C6 and the diode D4. The output end of the transformer T1 is provided with an output coil S1, an output coil S2, and an output coil S3. The transformer T1 isolates the electrical systems of the input and output ends to prevent electrical interference from being transmitted to the load equipment through the power grid. At the same time, the transformer T1 can also adjust the amplitude and phase of the output voltage as needed to meet the requirements of different load devices.

[0030] The input filter unit includes a capacitor C1, a capacitor C2, an inductor L1, an inductor L2, and a capacitor C3 and a capacitor C4 arranged in parallel. The connection ends of the diode D2 and the diode D4 are connected to a resistor R1, one end of the resistor R1 is connected to one end of the inductor L1, the capacitor C1 and the capacitor C2 are respectively connected to the two ends of the inductor L1, the inductor L2 is connected between the capacitor C1 and the capacitor C2, and the inductor L2 and the inductor L1 are respectively located at the two ends of the capacitor C1, the connection end of the capacitor C3 and the capacitor C4 is grounded, the other end of the capacitor C3 is connected to the connection end of the resistor R1 and the capacitor C2, and the other end of the capacitor C4 is connected to the connection end of the capacitor C2 and the inductor L2.

[0031] The output filter unit includes a first filter component connected to the output coil S1, a second filter component connected to the output coil S2, and a third filter component connected to the output coil S3. The first filter component is mainly composed of a capacitor C7, an inductor L3, and a capacitor C12. The capacitor C7 and the capacitor C12 are connected in parallel to the output coil S1. The inductor L3 is connected between the capacitor C7 and the capacitor C12. The connecting end of the inductor L3 and the capacitor C7 is connected to a diode D7. The diode D7 is connected to one end of the output coil S1.

[0032] The second filter component is mainly composed of a capacitor C8, an inductor L4 and a capacitor C11. The capacitor C8 and the capacitor C11 are connected in parallel to the output coil S2. The inductor L4 is connected between the capacitor C8 and the capacitor C11. The connecting end of the inductor L4 and the capacitor C8 is connected to a diode D6. The diode D6 is connected to one end of the output coil S2.

[0033] The third filter component is mainly composed of a capacitor C9, an inductor L5 and a capacitor C10. The capacitor C9 and the capacitor C10 are connected in parallel to the output coil S3. The inductor L5 is connected between the capacitor C9 and the capacitor C10. The connection end of the inductor L5 and the capacitor C9 is connected to a diode D5. The diode D5 is connected to one end of the output coil S3. The first filter component, the second filter component and the third filter component are used to filter the output side of the isolation transformer to prevent external interference signals from affecting the output of the isolation transformer.

[0034] The static switch includes a coupling chip U3. A transmitting end of the coupling chip U3 is connected to a resistor R5 for receiving a control signal. One control end of the coupling chip U3 is connected to a thyristor Q11. One end of the thyristor Q11 is connected to the other control end of the coupling chip U3 via a resistor R6. A resistor R7 is connected to the connection end of the thyristor Q11 and the coupling chip U3. A capacitor C33 and a resistor R8 are connected in series between the two control ends of the coupling chip U3. The non-connected ends of the capacitor C33 and the resistor R8 are respectively connected to two ends of the thyristor Q11. The cooperation between the coupling chip U3 and the thyristor Q11 provides a fast response characteristic, enabling circuit switching to be completed in a very short time, ensuring a smooth transition of the load between the mains power supply and the inverter power supply. When the mains power returns to normal, the static switch automatically switches the load back to the mains power supply. When the mains power is abnormal or interrupted, the static switch quickly switches the load to the inverter power supply.

[0035] The output circuit includes a voltage regulator chip U5, the input of which is connected to a ground capacitor C13, the output of which is connected to a ground capacitor C14, and a voltage regulator diode D8 connected between the output and input of the voltage regulator chip U5. The voltage regulator diode D8 is connected between the output and input of the voltage regulator chip U5 and provides overvoltage protection. When the output voltage rises abnormally, the voltage regulator diode D8 will turn on and discharge the excess voltage to ground, thereby protecting the voltage regulator chip and other circuit components from damage. The ground capacitor C13 is mainly used to filter high-frequency noise at the input, stabilize the input voltage, and prevent transient voltage interference from affecting the normal operation of the voltage regulator chip U5. The ground capacitor C14 is used for further filtering and smoothing the stabilized output voltage, reducing ripple and noise, and improving the stability of the output voltage.

[0036] The control circuit includes a DSP processor for accurately monitoring the mains power status, battery charge, and inverter operating status. One end of the DSP processor is connected to a single-chip microcomputer. Both the single-chip microcomputer and the DSP processor are connected to the inverter, rectifier, isolation transformer, and static switch. The DSP processor is responsible for monitoring parameters such as the mains power status, battery charge, and inverter operating status. The single-chip microcomputer controls the operation of each component based on these parameters. For example, when the mains power goes out, the control circuit controls the inverter to start, converting the direct current (DC) power of the battery pack into alternating current (AC) to power the load. When the mains power is restored, the control circuit controls the static switch to switch the load back to the mains power supply. The control circuit also monitors and adjusts the operating status of each component in real time to ensure stable system operation.

[0037] It should be noted that the battery pack, inverter, and rectifier all use the existing structure in the UPS system and have not been improved, so they will not be described in detail here.

[0038] Although the 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 variations may be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A topology structure of a UPS with a zero neutral-ground voltage, characterized by: It includes a battery pack, an inverter connected to the battery pack, a rectifier for converting input AC power into DC power, an isolation transformer for electrical isolation, a filter circuit and a control circuit for reducing interference signals generated by the grid side and the isolation transformer itself; The filtering circuit includes an input filtering unit and an output filtering unit, wherein the input filtering unit is connected to the input end of the isolation transformer, and the output filtering unit is connected to the output end of the isolation transformer; One end of the battery pack is connected to an inverter, the output end of the inverter is connected to a static switch capable of automatically switching circuits, one end of the static switch is connected to a filter circuit, one end of the filter circuit is connected to an isolation transformer, and the other end of the isolation transformer is connected to an output circuit with anti-reverse voltage transmission protection; The output end of the rectifier is connected to the battery pack and the static switch respectively, and the control circuit is connected to the inverter, the rectifier, the isolation transformer and the static switch respectively.

2. The topological structure of a UPS with zero neutral-ground voltage according to claim 1, characterized in that: The isolation transformer includes a transformer T1 and a driver chip for driving the transformer T1 to start. The input side of the transformer T1 is connected in parallel with a diode D1 and a diode D3 arranged in series, a diode D2 and a diode D4 arranged in series, and a capacitor C5 and a capacitor C6 arranged in series. The input side of the transformer T1 is connected to the driver chip through a transistor Q1. The emitter end of the transistor Q1 is connected to a resistor R2, and one end of the resistor R2 is connected to the connection end of the capacitor C6 and the diode D4. The output end of the transformer T1 is provided with an output coil S1, an output coil S2, and an output coil S3.

3. The topological structure of a UPS with zero neutral-ground voltage according to claim 2, characterized in that: The input filter unit includes a capacitor C1, a capacitor C2, an inductor L1, an inductor L2, and a capacitor C3 and a capacitor C4 arranged in parallel. The connection ends of the diode D2 and the diode D4 are connected to a resistor R1, one end of the resistor R1 is connected to one end of the inductor L1, the capacitor C1 and the capacitor C2 are respectively connected to the two ends of the inductor L1, the inductor L2 is connected between the capacitor C1 and the capacitor C2, and the inductor L2 and the inductor L1 are respectively located at the two ends of the capacitor C1, the connection end of the capacitor C3 and the capacitor C4 is grounded, the other end of the capacitor C3 is connected to the connection end of the resistor R1 and the capacitor C2, and the other end of the capacitor C4 is connected to the connection end of the capacitor C2 and the inductor L2.

4. The topological structure of a UPS with zero neutral-ground voltage according to claim 3, characterized in that: The output filter unit includes a first filter component connected to the output coil S1, a second filter component connected to the output coil S2, and a third filter component connected to the output coil S3. The first filter component is mainly composed of a capacitor C7, an inductor L3, and a capacitor C12. The capacitor C7 and the capacitor C12 are connected in parallel to the output coil S1. The inductor L3 is connected between the capacitor C7 and the capacitor C12. The connecting end of the inductor L3 and the capacitor C7 is connected to a diode D7. The diode D7 is connected to one end of the output coil S1. The second filter component is mainly composed of a capacitor C8, an inductor L4 and a capacitor C11. The capacitor C8 and the capacitor C11 are connected in parallel to the output coil S2. The inductor L4 is connected between the capacitor C8 and the capacitor C11. The connecting end of the inductor L4 and the capacitor C8 is connected to a diode D6. The diode D6 is connected to one end of the output coil S2. The third filter component is mainly composed of a capacitor C9, an inductor L5 and a capacitor C10. The capacitor C9 and the capacitor C10 are connected in parallel to the output coil S3. The inductor L5 is connected between the capacitor C9 and the capacitor C10. The connecting end of the inductor L5 and the capacitor C9 is connected to a diode D5, and the diode D5 is connected to one end of the output coil S3.

5. The topological structure of a UPS with zero neutral-ground voltage according to claim 4, characterized in that: The static switch includes a coupling chip U3, a transmitting end of the coupling chip U3 is connected to a resistor R5 for receiving a control signal, one control end of the coupling chip U3 is connected to a thyristor Q11, one end of the thyristor Q11 is connected to the other control end of the coupling chip U3 via a resistor R6, a connection end between the thyristor Q11 and the coupling chip U3 is connected to a resistor R7, a capacitor C33 and a resistor R8 arranged in series are connected between the two control ends of the coupling chip U3, and the non-connected ends of the capacitor C33 and the resistor R8 are respectively connected to two ends of the thyristor Q11.

6. The topological structure of a UPS with zero neutral-ground voltage according to claim 5, characterized in that: The output circuit includes a voltage stabilizing chip U5, the input end of the voltage stabilizing chip U5 is connected to a ground capacitor C13, the output end of the voltage stabilizing chip U5 is connected to a ground capacitor C14, and a voltage stabilizing diode D8 is connected between the output and input ends of the voltage stabilizing chip U5.

7. The topology structure of a UPS with zero neutral-ground voltage according to claim 1, characterized in that: The control circuit includes a DSP processor for accurately monitoring the mains status, battery power and inverter working status. One end of the DSP processor is connected to a single-chip microcomputer. The single-chip microcomputer and the DSP processor are both connected to the inverter, rectifier, isolation transformer and static switch.

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