Uninterruptible power supply, and power supply system

Abstract

Provided in the present application are an uninterruptible power supply, and a power supply system, which are used for reducing the cost of the uninterruptible power supply and improving the utilization rate of a circuit. The uninterruptible power supply comprises a mains supply input end, a switching circuit, a rectification circuit, an inverter circuit and a charging / discharging circuit, wherein the switching circuit comprises a first switch, a second switch and a third switch; and when an alternating current input from the mains supply input end has a fault, a controller controls the charging / discharging circuit to discharge, to a bus, electric energy that is stored in an energy storage apparatus, after the charging / discharging circuit supplies power to the bus, the controller controls the first switch to disconnect the mains supply input end from the rectification circuit, controls the second switch to connect the energy storage apparatus to the rectification circuit, and controls the third switch to disconnect the energy storage apparatus from the charging / discharging circuit, and thus the electric energy, which is output from the energy storage apparatus, is input to the rectification circuit, the rectification circuit performs power conversion on the electric energy, which is input from the energy storage apparatus, and then outputs the electric energy to the bus, and the inverter circuit converts a direct current on the bus into an alternating current and outputs the alternating current to a load.

Description

Uninterruptible power supply and power supply system

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on June 27, 2023, with application number 202310770674.9 and application name “An Uninterruptible Power Supply and Power Supply System”, the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of power electronics technology, and in particular to an uninterruptible power supply and a power supply system. Background Art

[0004] An uninterruptible power supply (UPS) is a power supply that includes an energy storage device. It is primarily used to provide uninterruptible power to electronic devices that require high power stability. A UPS primarily consists of a rectifier circuit (AC / DC), an inverter circuit (DC / AC), and a charge-discharge circuit (DC / DC). The rectifier circuit and the charge-discharge circuit are completely independent, providing energy to the DC bus in both the mains power supply mode and the energy storage device power supply mode, respectively. The inverter circuit then converts the DC power into AC power and supplies it to the load. Specifically, when the mains power input is normal, the UPS converts the mains power into stable DC power through the rectifier circuit, and then converts it into AC power through the inverter circuit to supply the load. At this point, the UPS is an AC mains voltage stabilizer, and it can also reversely charge the energy storage device through the charge-discharge circuit. When the mains power is interrupted or there is a power outage due to an accident, the UPS immediately switches to the energy storage device power supply mode. It first converts the energy of the energy storage device into stable DC power through the charging and discharging circuit, and then converts it into three-phase 380V or single-phase 220V AC power to the load through the inverter circuit, so that the load can maintain normal operation and protect the load power supply from interruption.

[0005] As can be seen from the UPS operating principle described above, the charge-discharge circuit is always active when powered by an energy storage device. The power of the charge-discharge circuit must meet the rated power of the UPS, which requires a relatively large circuit size. Furthermore, the rectifier circuit is only active when powered by mains electricity and is idle when powered by an energy storage device. This reduces circuit utilization, resulting in cost and space disadvantages.

[0006] Summary of the Invention

[0007] The embodiments of the present application provide an uninterruptible power supply and a power supply system to reduce the cost of the uninterruptible power supply and improve the circuit utilization of the uninterruptible power supply.

[0008] To achieve the above objectives, this application adopts the following technical solutions:

[0009] According to a first aspect of an embodiment of the present application, an uninterruptible power supply (UPS) is provided, which may specifically include: a mains input terminal, a switching circuit, a rectifier circuit, an inverter circuit, and a charge-discharge circuit. The switching circuit may specifically include: a first switch, a second switch, and a third switch. The first end of the first switch is connected to the mains input terminal, and the second end of the first switch is connected to the input terminal of the rectifier circuit. The first switch can control the on / off state between the mains input terminal and the rectifier circuit. The first end of the second switch is connected to an energy storage device, and the second end of the second switch is connected to the input terminal of the rectifier circuit. The second switch can control the on / off state between the energy storage device and the rectifier circuit. The first end of the third switch is connected to the energy storage device, and the second end of the third switch is connected to the first end of the charge-discharge circuit. The third switch can control the on / off state between the charge-discharge circuit and the energy storage device. In a small UPS, the energy storage device may be internal to the UPS or external to the UPS. In a medium- to large-sized UPS, the energy storage device is large and is generally placed external to the UPS. The energy storage device may specifically be a device with charge-discharge functions, such as a battery pack. The output of the rectifier circuit is connected to the busbar. It converts the incoming AC power or energy from the energy storage device into DC power to power the busbar. The second end of the charge-discharge circuit is connected to the busbar. It supplies power to the busbar or charges the energy storage device from the busbar. The input of the inverter circuit is connected to the busbar. The output of the inverter circuit is connected to the load. The inverter circuit converts the DC power on the busbar into AC power to power the load.

[0010] In the embodiment of the present application, the switching circuit, the rectifier circuit, the inverter circuit and the charge-discharge circuit can be composed of devices such as switches, switching tubes, diodes, inductors and capacitors. The operating states of the switching circuit, the rectifier circuit, the inverter circuit and the charge-discharge circuit can be achieved by adjusting the operating states of these devices. Specifically, the operating state adjustment of the above-mentioned devices can be achieved by a controller, that is, the uninterruptible power supply can also include a controller, which can control the on-off state of the switching circuit, control the rectifier circuit to convert the received electrical energy into direct current to supply power to the bus, control the inverter circuit to convert the direct current on the bus into alternating current, and control the charge-discharge state of the charge-discharge circuit. In specific implementation, the controller can be any one of a microcontroller unit (MCU), a central processing unit (CPU), and a digital signal processor (DSP). Of course, the specific form of the controller is not limited to the above examples.

[0011] When the AC power input at the mains input terminal is normal, for example, by determining that the voltage amplitude of the AC power received at the mains input terminal is within a set threshold range, the above-mentioned uninterruptible power supply provided in the embodiment of the present application is in the mains power supply mode. The controller can control the first switch to connect the AC power to the rectifier circuit, control the second switch to connect the energy storage device to the charge-discharge circuit, and control the third switch to disconnect the energy storage device from the rectifier circuit. In addition, the controller controls the rectifier circuit to convert the received AC power into DC power, controls the inverter circuit to convert the DC power on the bus into AC power and supply power to the load, and controls the charge-discharge circuit to charge the energy storage device.

[0012] When the AC power input at the mains input terminal fails, for example, it can be determined that the AC power has failed by determining that the voltage amplitude of the AC power received at the mains input terminal is outside the set threshold range. The failure may be caused by reasons such as AC power interruption or power outage. The above-mentioned uninterruptible power supply provided in the embodiment of the present application will switch from the mains power supply mode to the energy storage device power supply mode. The controller can control the charge and discharge circuit to quickly switch from the charging state to the discharging state, discharge the electric energy stored in the energy storage device to the bus, and quickly reverse the power supply to the bus. Since it only involves the control switching of the internal switch tube of the charge and discharge circuit, this process is extremely fast and can be completed within tens of us, thereby ensuring that the DC power of the bus is not cut off. After the controller controls the charge and discharge circuit to supply power to the bus, the controller can control the first switch to disconnect the AC power supply and the rectifier circuit, and then control the second switch to connect the energy storage device and the rectifier circuit, so that the electric energy output by the energy storage device is input to the rectifier circuit, so that the uninterruptible power supply starts to work in the energy storage device power supply mode. Furthermore, after the uninterruptible power supply begins operating in the energy storage device power supply mode, the controller can control the third switch to disconnect the energy storage device from the charge-discharge circuit, causing the charge-discharge circuit to stop reverse operation and supply power to the bus. The rectifier circuit converts the power received from the energy storage device and outputs it to the bus. The inverter circuit converts the DC power on the bus into AC power and outputs it to the load.

[0013] Specifically, the switches that make up the switching circuit can be implemented using relays. Due to the characteristics of the relays, the on-off switching process takes anywhere from a few milliseconds to tens of milliseconds. In other words, the charge-discharge circuit only takes a few to tens of milliseconds to reversely power the busbar. Because this short reverse operation time allows the charge-discharge circuit to operate at excess capacity, for example, enabling the actual discharge power of the charge-discharge circuit to exceed twice its rated discharge power. This reduces the current specifications of the circuit components, saving cost and size.

[0014] In some embodiments of the present application, the busbars in the uninterruptible power supply may specifically include a positive busbar, a negative busbar, a first busbar capacitor, and a second busbar capacitor. The first busbar capacitor and the second busbar capacitor are connected in series between the positive busbar and the negative busbar, and the midpoint of the first busbar capacitor and the second busbar capacitor is connected to the neutral line. The positive busbar is used to transmit positive direct current, the negative busbar is used to transmit negative direct current, the first busbar capacitor is used to store the electrical energy of the positive busbar, and the second busbar capacitor is used to store the electrical energy of the negative busbar. In actual use, the inverter circuit converts the electrical energy stored in the first busbar capacitor into a positive half-cycle signal of the second alternating current, and the inverter circuit converts the electrical energy stored in the second busbar capacitor into a negative half-cycle signal of the alternating current. The electrical energy values ​​stored in the first busbar capacitor and the second busbar capacitor are equal. When the electrical equipment, i.e., the load, has different requirements for the electrical energy in the positive and negative half-cycles of the alternating current, the electrical energy stored in the first busbar capacitor and the second busbar capacitor cannot meet the electrical energy requirements of the electrical equipment. In order to ensure that the electric energy stored in the first bus capacitor and the second bus capacitor can meet the needs of the electrical equipment, a balancing circuit needs to be set in the uninterruptible power supply. The balancing circuit can realize the electric energy regulation between the positive bus and the negative bus. The adjusted positive bus electric energy and negative bus electric energy can meet the electric energy requirements of the electrical equipment.

[0015] Based on this, in some embodiments of the present application, the switching circuit may further include a fourth switch, wherein the first end of the fourth switch is used to connect to the neutral line, and the second end of the fourth switch is connected to the first end of the charge and discharge circuit. In some embodiments of the present application, the third switch and the fourth switch may form a single-pole double-throw switch. Alternatively, in other embodiments of the present application, the third switch and the fourth switch may also be two independent single-pole single-throw switches, which are not limited here. After the uninterruptible power supply starts to operate in the energy storage device power supply mode, the controller controls the third switch to disconnect while controlling the fourth switch to conduct the charge and discharge circuit and the neutral line, so that the charge and discharge circuit is used as a balancing circuit, that is, the controller controls the conduction of the switch tube in the charge and discharge circuit so that the voltage on the bus with a higher voltage between the positive bus and the negative bus is released to the neutral line to balance the voltage difference between the positive and negative buses, so that the uninterruptible power supply can work more stably when supplying power to loads with unbalanced positive and negative power demands.

[0016] When the AC power input at the mains input terminal returns to normal, the above-mentioned uninterruptible power supply provided in the embodiment of the present application will switch from the energy storage device power supply mode back to the mains power supply mode. The controller can control the fourth switch to disconnect the charge and discharge circuit from the neutral line, and control the third switch to turn on the energy storage device and the charge and discharge circuit, control the charge and discharge circuit to discharge the electric energy stored in the energy storage device to the bus, and use the charge and discharge circuit to replenish energy for the bus, thereby ensuring that the DC power of the bus is not cut off during the process of switching to the mains power supply mode. After controlling the charge and discharge circuit to supply power to the bus, the controller can control the second switch to disconnect the energy storage device and the rectifier circuit, and control the first switch to turn on the AC input terminal and the rectifier circuit, so that the AC power input at the mains input terminal is converted into DC power by the rectifier circuit and then supplies power to the bus, so that the uninterruptible power supply starts to work in the mains power supply mode. In addition, the controller can also control the charge and discharge circuit to charge the energy storage device.

[0017] In an embodiment of the present application, in both the mains power supply mode and the energy storage device power supply mode, the rectifier circuit is in working state, that is, in both the mains power supply mode and the energy storage device power supply mode, the topology of the rectifier circuit is shared, which can reduce the circuit volume and cost. The charge and discharge circuit can be used as a charging circuit, a discharging circuit and a bus balancing circuit, making full use of the topology of the charge and discharge circuit, which can reduce the circuit volume and cost. Moreover, by the short-term power supply to the bus by the charge and discharge circuit, the bus energy supply during the switching process of the switching circuit between the mains power supply mode and the energy storage device power supply mode can be supported, and the reverse power supply of the charge and discharge circuit can be applied in excess, for example, the actual discharge power of the charge and discharge circuit is greater than twice the rated discharge power of the charge and discharge circuit, which can reduce the current specification of the circuit device to save cost and volume. In addition, in the energy storage device power supply mode, by switching the switching circuit, the charge and discharge circuit can be reused as a bus balancing circuit, and the reused circuit can reduce the circuit volume and cost.

[0018] In some embodiments of the present application, the first end of the second switch can be connected to the positive electrode of the energy storage device, and correspondingly, the negative electrode of the energy storage device is connected to the negative busbar of the busbars. The second switch can control the on-off state between the positive electrode of the energy storage device and the rectifier circuit. The first end of the third switch can be connected to the positive electrode of the energy storage device, and the third switch can control the on-off state between the charge-discharge circuit and the positive electrode of the energy storage device.

[0019] In other embodiments of the present application, the first end of the second switch can be connected to the negative electrode of the energy storage device, and accordingly, the positive electrode of the energy storage device is connected to the positive busbar of the busbars, and the second switch can control the on-off state between the negative electrode of the energy storage device and the rectifier circuit. The first end of the third switch can be connected to the negative electrode of the energy storage device, and the third switch can control the on-off state between the charge-discharge circuit and the negative electrode of the energy storage device.

[0020] In some embodiments of the present application, the rectifier circuit may specifically include: a first inductor, a first switching transistor, a second switching transistor, a third switching transistor, and a diode. The first end of the first inductor is connected to the first output terminal of the switching circuit, the second end of the first inductor is connected to the first electrode of the second switching transistor, the second electrode of the second switching transistor is connected to the second electrode of the third switching transistor, and the first electrode of the third switching transistor is connected to the neutral line.

[0021] When the first end of the second switch and the first end of the third switch are both connected to the positive electrode of the energy storage device, the first electrode of the first switching tube is connected to the negative bus, and the second electrode of the first switching tube is connected to the second end of the first inductor; the positive electrode of the diode is connected to the second end of the first inductor, and the negative electrode of the diode is connected to the positive bus.

[0022] When the first end of the second switch and the first end of the third switch are both connected to the negative electrode of the energy storage device, the first electrode of the first switching tube is connected to the second end of the first inductor, and the second electrode of the first switching tube is connected to the positive bus; the positive electrode of the diode is connected to the negative bus, and the negative electrode of the diode is connected to the second end of the first inductor.

[0023] In some embodiments of the present application, the charge and discharge circuit may include: a second inductor, a fourth switching tube, a fifth switching tube, a first capacitor, and a second capacitor. The first end of the second inductor is connected to the second output terminal of the switching circuit, and the second end of the second inductor is connected to the first end of the fourth switching tube and the second end of the fifth switching tube, respectively. The fourth switching tube, the fifth switching tube, the first capacitor, and the second capacitor can form a low-power charge and discharge circuit in a half-bridge topology. Its power is approximately only 30% of the power of a full-power charge and discharge circuit, but by overworking for a short period of time, it can achieve the effect of a full-power charge and discharge circuit, which can save cost and circuit volume compared to a full-power charge and discharge circuit. Specifically, the second end of the fourth switching tube is connected to the positive bus, and the first end of the fifth switching tube is connected to the negative bus. The first capacitor is connected between the positive bus and the neutral line, that is, the first capacitor is arranged in parallel with the first bus capacitor, and the second capacitor is connected between the negative bus and the neutral line, that is, the second capacitor is arranged in parallel with the second bus capacitor. When the charge and discharge circuit is used as a balancing circuit, when the controller determines that the voltage of the positive bus is higher than the voltage of the negative bus, it can control the fourth switch tube to turn on and the fifth switch tube to turn off, so that the voltage of the positive bus is released to the neutral line; when the controller determines that the voltage of the negative bus is higher than the voltage of the positive bus, it can control the fifth switch tube to turn on and the fourth switch tube to turn off, so that the voltage of the negative bus is released to the neutral line.

[0024] In an embodiment of the present application, the inverter circuit may adopt a two-level half-bridge topology, a T-type or I-type three-level half-bridge topology, or other topologies. Taking the inverter circuit adopting a T-type three-level topology as an example, the inverter circuit may include: a third inductor, a sixth switch tube, a seventh switch tube, an eighth switch tube, and a ninth switch tube. The first end of the sixth switch tube is connected to the neutral line, and the second end of the sixth switch tube is connected to the second end of the seventh switch tube. The first end of the third inductor is connected to the first end of the seventh switch tube, and the second end of the third inductor is connected to the output end for supplying power to the load. The first end of the eighth switch tube is connected to the first end of the third inductor, and the second end of the eighth switch tube is connected to the positive bus. The first end of the ninth switch tube is connected to the negative bus, and the second end of the ninth switch tube is connected to the first end of the third inductor.

[0025] The switching tubes in the above-mentioned rectifier circuit, inverter circuit, and charge-discharge circuit provided in the embodiments of the present application may include parallel diodes and transistors. Specifically, the switching tube may be a metal oxide semiconductor field effect transistor (MOSFET), which naturally has a reverse diode function. The switching tube may also be an insulated gate bipolar transistor (IGBT) or a bipolar junction transistor (BJT) with a built-in diode. The switching tube may also be an independent diode-parallel gallium nitride field effect transistor (GaN), a silicon carbide (SiC) power tube, or one or more of various types of transistor devices, which are not listed one by one in the embodiments of the present application.

[0026] Specifically, each switch tube may include a first electrode, a second electrode, and a control electrode, wherein the control electrode is used to control the on / off state of the switch tube. When the switch tube is on, current can be transmitted between the first electrode and the second electrode of the switch tube. When the switch tube is off, current cannot be transmitted between the first electrode and the second electrode of the switch tube. Taking MOSFET as an example, the control electrode of the switch tube is the gate electrode, the first electrode of the switch tube can be the source electrode of the switch tube, and the second electrode can be the drain electrode of the switch tube. Alternatively, the first electrode can be the drain electrode of the switch tube, and the second electrode can be the source electrode of the switch tube.

[0027] In other embodiments of the present application, the AC power received by the uninterruptible power supply can also output three-phase AC power, such as phase A, phase B, and phase C. Correspondingly, the uninterruptible power supply may include three rectifier circuits and three inverter circuits corresponding to each phase of the three-phase AC power (i.e., phase A, phase B, and phase C). Each rectifier circuit is used to convert the received electrical energy of the energy storage device or the corresponding single-phase AC power (i.e., phase A, phase B, and phase C) into DC power and output it to the bus, and each inverter circuit is used to convert the DC power on the bus into AC power and supply power to the load. The rectifier circuit corresponding to each phase of AC power may include a first inductor, a first switch tube, a second switch tube, a third switch tube, and a diode. The inverter circuit corresponding to each phase of AC power may include a third inductor, a sixth switch tube, a seventh switch tube, an eighth switch tube, and a ninth switch tube. The topological structure in each rectifier circuit and each inverter circuit can refer to the topological structure of single-phase AC power and will not be described in detail here.

[0028] Correspondingly, the switching circuit may include three first switches and three second switches corresponding to each phase of the three-phase AC power (i.e., phase A, phase B, and phase C). The first end of each first switch is used to receive the corresponding phase of AC power, the second end of each first switch is connected to the input end of the rectifier circuit corresponding to the phase of AC power, and the second end of each second switch is connected to the input end of the rectifier circuit corresponding to the phase of AC power.

[0029] The second aspect of the embodiment of the present application provides a power supply system, including an energy storage device and an uninterruptible power supply, and the uninterruptible power supply provides an uninterruptible power supply of any possible design for the first aspect, and the repetitions are not repeated. The energy storage device can be connected to the first end of the second switch of the switching circuit in the uninterruptible power supply. Specifically, the power supply system is connected between the AC power supply and the electrical equipment, and the power supply system is used to power the electrical equipment through the AC power output by the AC power supply. When applied to a small power supply system, the energy storage device can be built into the UPS or externally placed outside the UPS. When applied to medium and large power supply systems, the energy storage device is large in size and is generally placed outside the UPS.

[0030] The technical effects that can be achieved in the second aspect mentioned above can be described with reference to the technical effects that can be achieved by any possible design in the first aspect mentioned above, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] FIG1 is a schematic diagram of the structure of an uninterruptible power supply provided in an embodiment of the present application;

[0032] FIG2 is another schematic diagram of the structure of an uninterruptible power supply provided in an embodiment of the present application;

[0033] FIG3 is another structural diagram of an uninterruptible power supply provided in an embodiment of the present application;

[0034] FIG4 is a schematic diagram of a specific circuit structure of an uninterruptible power supply provided in an embodiment of the present application;

[0035] FIG5 is a schematic diagram of another specific circuit structure of an uninterruptible power supply provided in an embodiment of the present application;

[0036] FIG6 is a schematic diagram of another specific circuit structure of an uninterruptible power supply provided in an embodiment of the present application;

[0037] FIG7 is a schematic diagram of another specific circuit structure of an uninterruptible power supply provided in an embodiment of the present application;

[0038] FIG8 a is a schematic diagram showing the working principle of the rectifier circuit of the uninterruptible power supply provided by an embodiment of the present application in the positive half cycle in the mains power supply mode;

[0039] FIG8 b is a schematic diagram showing the working principle of the rectifier circuit of the uninterruptible power supply provided by an embodiment of the present application in the negative half cycle in the mains power supply mode;

[0040] FIG8 c is a schematic diagram showing the working principle of the charging and discharging circuit of the uninterruptible power supply provided by an embodiment of the present application in the mains power supply mode;

[0041] FIG9a is a schematic diagram showing the working principle of the uninterruptible power supply provided by an embodiment of the present application, in which the charging and discharging circuit supplies power to the busbar when an AC power supply fails;

[0042] FIG9 b is a schematic diagram of a working principle of an uninterruptible power supply provided in an embodiment of the present application in an energy storage device power supply mode;

[0043] FIG9 c is a schematic diagram of another working principle of the uninterruptible power supply provided in an embodiment of the present application in an energy storage device power supply mode;

[0044] 9d is a schematic diagram showing the working principle of the charging and discharging circuit of the uninterruptible power supply provided in an embodiment of the present application as a bus balancing circuit in the energy storage device power supply mode.

[0045] Figure 1: 100-uninterruptible power supply, 200-AC power supply, 300-energy storage device, 400-load, 11-switching circuit, 12-rectifier circuit, 13-inverter circuit, 14-charge and discharge circuit, 15-bus, T1-first switch, T2-second switch, T3-third switch, T4-fourth switch, Bat+-positive electrode, Bat--negative electrode, N-neutral line, +BUS-positive bus, -BUS-negative bus, D-diode, Q1, Q1a, Q1b, Q1c-first switch tube, Q2, Q2a, Q2b, Q2c-second switch tube, Q3, Q3a, Q 3b, Q3c - third switching tube, L1, L1a, L1b, L1c - first inductor, L2 - second inductor, L3, L3a, L3b, L3c - third inductor, C1 - first bus capacitor, C2 - second bus capacitor, C11 - first capacitor, C12 - second capacitor, Q4 - fourth switching tube, Q5 - fifth switching tube, Q6, Q6a, Q6b, Q6c - sixth switching tube, Q7, Q7a, Q7b, Q7c - seventh switching tube, Q8, Q8a, Q8b, Q8c - eighth switching tube, Q9, Q9a, Q9b, Q9c - ninth switching tube. DETAILED DESCRIPTION

[0046] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0047] Hereinafter, the terms "second," "first," etc., are used for descriptive convenience only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature qualified as "second," "first," etc., may explicitly or implicitly include one or more of such features. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0048] In addition, in the embodiments of the present application, directional terms such as "up", "down", "left", and "right" may be defined including but not limited to the orientation relative to the schematic placement of the components in the drawings. It should be understood that these directional terms may be relative concepts, which are used for relative descriptions and clarifications, and may change accordingly according to changes in the orientation of the components in the drawings.

[0049] In the embodiments of this application, unless otherwise specified or limited, the term "connection" should be understood in a broad sense. For example, "connection" can mean fixed connection, detachable connection, or integration; it can mean direct connection or indirect connection through an intermediate medium. In addition, the term "coupling" can mean direct electrical connection or indirect electrical connection through an intermediate medium. The term "contact" can mean direct contact or indirect contact through an intermediate medium.

[0050] In the embodiments of the present application, "and / or" describes the relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, and B exists alone. A and B can be singular or plural. The character " / " generally indicates that the associated objects are in an "or" relationship.

[0051] FIG1 schematically shows a structural diagram of an uninterruptible power supply provided in an embodiment of the present application, and FIG2 schematically shows another structural diagram of an uninterruptible power supply provided in an embodiment of the present application.

[0052] 1 , an uninterruptible power supply 100 provided in an embodiment of the present disclosure may specifically include: a mains input terminal, a switching circuit 11, a rectifier circuit 12, an inverter circuit 13, and a charge-discharge circuit 14. The mains input terminal is used to connect to an AC power source 200, the first input terminal of the switching circuit 11 is used to connect to the mains input terminal, and the second input terminal of the switching circuit 11 is used to connect to an energy storage device 300. When applied to a small UPS, the energy storage device 300 may be built into the UPS or externally located outside the UPS. Referring to FIG2 , when applied to a medium or large UPS, the energy storage device 300 is large in size and is generally placed outside the UPS. The energy storage device 300 may specifically be a device with charge-discharge functions, such as a battery pack. The first output terminal of the switching circuit 11 is connected to the input terminal of the rectifier circuit 12, and the second output terminal of the switching circuit 11 is connected to the first terminal of the charge-discharge circuit 14. The switching circuit 11 is used to control the on / off state between the AC power source 200 and the rectifier circuit 12, the on / off state between the energy storage device 300 and the charge / discharge circuit 14, and the on / off state between the energy storage device 300 and the rectifier circuit 12. The output end of the rectifier circuit 12 is connected to the bus 15. The rectifier circuit 12 is used to convert the received AC power or the power energy of the energy storage device 300 into DC power to power the bus 15. The second end of the charge / discharge circuit 14 is connected to the bus 15. The charge / discharge circuit 14 is used to power the bus 15 or charge the energy storage device 300 from the bus 15. The input end of the inverter circuit 13 is connected to the bus 15. The output end of the inverter circuit 13 is used to connect to the load 400. The inverter circuit 13 is used to convert the DC power on the bus 15 into AC power and power the load 400.

[0053] In the embodiment of the present application, the switching circuit 11, the rectifier circuit 12, the inverter circuit 13, and the charge-discharge circuit 14 can be composed of components such as a switch T, a switch tube Q, a diode D, an inductor L, and a capacitor C. The operating states of the switching circuit 11, the rectifier circuit 12, the inverter circuit 13, and the charge-discharge circuit 14 can be achieved by adjusting the operating states of these components. Specifically, the operating state adjustment of the above components can be achieved by a controller, that is, the uninterruptible power supply 100 can also include a controller, which can control the on-off state of the switching circuit 11, control the rectifier circuit 12 to convert the received electrical energy into direct current to supply the bus 15, control the inverter circuit 13 to convert the direct current on the bus 15 into alternating current, and control the charge and discharge state of the charge-discharge circuit 14. In specific implementation, the controller can be any one of a microcontroller unit (MCU), a central processing unit (CPU), and a digital signal processor (DSP). Of course, the specific form of the controller is not limited to the above example.

[0054] When the AC power input at the mains input terminal is normal, for example, the AC power can be determined to be normal by determining whether the voltage amplitude of the AC power received at the mains input terminal is within a set threshold range. The uninterruptible power supply 100 provided in the embodiment of the present application can be in a mains power supply mode, and the controller can control the switching circuit 11 to connect the AC power source 200 and the rectifier circuit 12, connect the energy storage device 300 and the charge-discharge circuit 14, and disconnect the energy storage device 300 from the rectifier circuit 12. The controller can control the rectifier circuit 12 to convert the received AC power into DC power to power the bus 15, control the inverter circuit 13 to convert the DC power on the bus 15 into AC power and power the load 400, and control the charge-discharge circuit 14 to be in a charging state to charge the bus 15 to the energy storage device 300.

[0055] When the AC power input to the mains input terminal fails, for example, it can be determined that the AC power fails by determining that the voltage amplitude of the AC power received at the mains input terminal is outside a set threshold range. The failure may be caused by an AC power interruption or an accidental power outage. The above-mentioned uninterruptible power supply 100 provided in the embodiment of the present application will switch from the mains power supply mode to the energy storage device 300 power supply mode. The controller can control the charge and discharge circuit 14 to quickly switch from the charging state to the discharging state, that is, control the charge and discharge circuit 14 to discharge the electric energy stored in the energy storage device 300 to the bus 15, and quickly reverse power to the bus 15. Since it only involves the control switching of the internal switch tube of the charge and discharge circuit 14, this process is extremely fast and can be completed within tens of us, thereby ensuring that the DC power of the bus 15 is not powered off. After the controller controls the charge-discharge circuit 14 to supply power to the bus 15, the controller can control the switching circuit 11 to switch the conductive state between the AC power source 200 and the rectifier circuit 12 to the disconnected state, and then switch the disconnected state between the energy storage device 300 and the rectifier circuit 12 to the conductive state, so that the power output by the energy storage device 300 is input into the rectifier circuit 12, causing the uninterruptible power supply 100 to begin operating in the energy storage device 300 power supply mode. Furthermore, after the uninterruptible power supply 100 begins operating in the energy storage device 300 power supply mode, the controller can also control the switching circuit 11 to switch the conductive state between the energy storage device 300 and the charge-discharge circuit 14 to the disconnected state, causing the charge-discharge circuit 14 to stop reverse operation and supply power to the bus 15. The rectifier circuit 12 can convert the power received from the energy storage device 300 and output it to the bus 15. The inverter circuit 13 converts the power on the bus 15 into AC power and outputs it to the load 400. The switching circuit 11 is generally composed of multiple switches, which can be implemented using relays. Depending on the characteristics of the switches, the switching process can take anywhere from a few milliseconds to tens of milliseconds. In other words, the charge-discharge circuit 14 only takes a few to tens of milliseconds to reversely power the bus 15. Because the reverse operation time of the charge-discharge circuit 14 is short, the charge-discharge circuit 14 can operate in excess of its rated power during reverse operation, for example, making the actual discharge power of the charge-discharge circuit 14 greater than twice its rated discharge power. This reduces the current specifications of the circuit components, saving cost and size.

[0056] FIG3 schematically shows another structural diagram of an uninterruptible power supply provided in an embodiment of the present application.

[0057] Referring to Figure 3, in some embodiments of the present application, the bus 15 in the uninterruptible power supply 100 may specifically include a positive bus +BUS, a negative bus -BUS, a first bus capacitor C1, and a second bus capacitor C2. The first bus capacitor C1 and the second bus capacitor C2 are connected in series between the positive bus +BUS and the negative bus -BUS, with the midpoint of the first bus capacitor C1 and the second bus capacitor C2 connected to the neutral line N. The positive bus +BUS is used to transmit positive direct current, and the negative bus -BUS is used to transmit negative direct current. The first bus capacitor C1 is used to store electrical energy from the positive bus +BUS, and the second bus capacitor C2 is used to store electrical energy from the negative bus -BUS. In actual use, the inverter circuit 13 converts the electrical energy stored in the first bus capacitor C1 into a positive half-cycle signal of the second alternating current, and the inverter circuit 13 converts the electrical energy stored in the second bus capacitor C2 into a negative half-cycle signal of the alternating current. The electrical energy stored in the first bus capacitor C1 and the second bus capacitor C2 is equal. When the electrical equipment, i.e., the load 400, has different energy requirements for the positive and negative half-cycles of the AC power, the electrical energy stored in the first bus capacitor C1 and the second bus capacitor C2 cannot meet the electrical energy requirements of the electrical equipment. To ensure that the electrical energy stored in the first bus capacitor C1 and the second bus capacitor C2 can meet the electrical equipment's requirements, a balancing circuit is required in the uninterruptible power supply 100. The balancing circuit can adjust the electrical energy between the positive bus +BUS and the negative bus -BUS. The adjusted positive bus +BUS energy and negative bus -BUS energy can meet the electrical energy requirements of the electrical equipment.

[0058] 3 , in some embodiments of the present application, the third output terminal of the switching circuit 11 can be connected to the neutral line N. After the uninterruptible power supply 100 begins operating in the energy storage device 300 power supply mode, the switching circuit 11 disconnects the energy storage device 300 from the charge-discharge circuit 14 while also connecting the charge-discharge circuit 14 to the neutral line N, allowing the charge-discharge circuit 14 to function as a balancing circuit. That is, the controller controls the conduction of the switches in the charge-discharge circuit 14 so that the voltage on the higher-voltage bus, the positive bus +BUS or the negative bus -BUS, is released to the neutral line N, thereby balancing the voltage difference between the positive and negative buses. This allows the uninterruptible power supply 100 to operate more stably when supplying power to a load 400 with an unbalanced positive and negative power demand.

[0059] When the AC power input at the mains input returns to normal, the uninterruptible power supply 100 provided in the embodiment of the present application will switch from the energy storage device 300 power supply mode back to the mains power supply mode. The controller can control the switching circuit 11 to disconnect the charge and discharge circuit 14 from the neutral line N, and control the switching circuit 11 to connect the energy storage device 300 and the charge and discharge circuit 14, control the charge and discharge circuit 14 to discharge the electric energy stored in the energy storage device 300 to the bus 15, and use the energy storage device 300 to replenish energy for the bus 15 through the charge and discharge circuit 14, thereby ensuring that the DC power of the bus 15 is not lost during the process of switching to the mains power supply mode. After the charge and discharge circuit 14 supplies the electric energy stored in the energy storage device 300 to the bus 15, the controller can control the switching circuit 11 to switch the conductive state of the energy storage device 300 and the rectifier circuit 12 to the disconnected state, and then switch the disconnected state of the AC power supply 200 and the rectifier circuit 12 to the conductive state, so that the uninterruptible power supply 100 starts to operate in the mains power supply mode. After the uninterruptible power supply 100 starts operating in the mains power supply mode, the controller can control the rectifier circuit 12 to convert AC power into DC power and output it to the bus 15, control the inverter circuit 13 to convert DC power on the bus 15 into AC power and output it to the load 400, and control the charge and discharge circuit 14 to charge the electric energy on the bus 15 to the energy storage device 300.

[0060] In an embodiment of the present application, in both the mains power supply mode and the energy storage device 300 power supply mode, the rectifier circuit 12 is in working state, that is, in both the mains power supply mode and the energy storage device 300 power supply mode, the topology of the rectifier circuit 12 is shared, which can reduce the circuit volume and cost. The charge and discharge circuit 14 can be used as a charging circuit, a discharging circuit and a bus balancing circuit, making full use of the topology of the charge and discharge circuit 14, which can reduce the circuit volume and cost. In addition, by the short-term power supply of the charge and discharge circuit 14 to the bus 15, the switching circuit 11 supports the energy supply of the bus 15 during the switching process between the mains power supply mode and the energy storage device 300 power supply mode, and the reverse power supply of the charge and discharge circuit 14 can be applied in excess, for example, the actual discharge power of the charge and discharge circuit 14 is greater than twice the rated discharge power of the charge and discharge circuit 14, which can reduce the current specification of the circuit device to save cost and volume. In addition, in the energy storage device 300 power supply mode, the charge and discharge circuit 14 can be reused as a bus balancing circuit by switching the switching circuit 11, and the reused circuit can reduce the circuit volume and cost.

[0061] Next, the specific structures of the switching circuit 11, the rectifier circuit 12, the charge-discharge circuit 14, and the inverter circuit 13 in the uninterruptible power supply 100 are described.

[0062] FIG4 schematically shows a specific circuit structure diagram of the uninterruptible power supply provided in an embodiment of the present application, and FIG5 schematically shows another specific circuit structure diagram of the uninterruptible power supply provided in an embodiment of the present application.

[0063] 4 and 5 , in some embodiments of the present application, the AC power supply 200 connected to the uninterruptible power supply 100 can output single-phase AC power. The switching circuit 11 can specifically include: a first switch T1, a second switch T2, and a third switch T3. The first end of the first switch T1 is connected to the mains input terminal Input of the single-phase AC power, and the second end of the first switch T1 is connected to the input terminal of the rectifier circuit 12. The first switch T1 can control the on-off state between the mains input terminal Input and the rectifier circuit 12. Optionally, a fuse can also be provided between the mains input terminal Input and the first end of the first switch T1. The first end of the second switch T2 is used to connect the energy storage device 300, and the second end of the second switch T2 is connected to the input terminal of the rectifier circuit 12. The second switch T2 can control the on-off state between the energy storage device 300 and the rectifier circuit 12. The first end of the third switch T3 is used to connect to the energy storage device 300 , and the second end of the third switch T3 is connected to the first end of the charge and discharge circuit 14 . The third switch T3 can control the on / off state between the charge and discharge circuit 14 and the energy storage device 300 .

[0064] Specifically, referring to FIG4 , in some embodiments of the present application, a first end of the second switch T2 can be connected to the positive electrode Bat+ of the energy storage device 300. Correspondingly, the negative electrode Bat- of the energy storage device 300 is connected to the negative bus -BUS in the bus 15. The second switch T2 can control the on / off state between the positive electrode Bat+ of the energy storage device 300 and the rectifier circuit 12. A first end of the third switch T3 can be connected to the positive electrode Bat+ of the energy storage device 300. The third switch T3 can control the on / off state between the charge-discharge circuit 14 and the positive electrode Bat+ of the energy storage device 300.

[0065] Alternatively, referring to FIG. 5 , in some other embodiments of the present application, the first end of the second switch T2 can be connected to the negative electrode Bat- of the energy storage device 300. Accordingly, the positive electrode Bat+ of the energy storage device 300 is connected to the positive bus +BUS in the bus 15. The second switch T2 can control the on / off state between the negative electrode Bat- of the energy storage device 300 and the rectifier circuit 12. The first end of the third switch T3 can be connected to the negative electrode Bat- of the energy storage device 300. The third switch T3 can control the on / off state between the charge-discharge circuit 14 and the negative electrode Bat- of the energy storage device 300.

[0066] 4 and 5 , in some embodiments of the present application, the switching circuit 11 may further include a fourth switch T4. A first end of the fourth switch T4 is used to connect to the neutral line N, and a second end of the fourth switch T4 is connected to a first end of the charge-discharge circuit 14. The fourth switch T4 may control the on / off state between the charge-discharge circuit 14 and the neutral line N. When the AC power inputted from the mains input terminal Input fails, the controller may control the third switch T3 to be disconnected and the fourth switch T4 to be turned on, so that the charge-discharge circuit 14 functions as a balancing circuit. That is, the controller controls the charge-discharge circuit 14 to balance the voltage difference between the positive bus +BUS and the negative bus -BUS, so that the uninterruptible power supply 100 operates more stably when supplying power to a load 400 having an unbalanced positive and negative power demand.

[0067] 4 , in some embodiments of the present application, the third switch T3 and the fourth switch T4 may form a single-pole double-throw switch. Alternatively, in some other embodiments of the present application, the third switch T3 and the fourth switch T4 may be two independent single-pole single-throw switches, as shown in FIG5 .

[0068] Referring to Figures 4 and 5 , in some embodiments of the present application, the rectifier circuit 12 may specifically include: a first inductor L1, a first switch Q1, a second switch Q2, a third switch Q3, and a diode D. The first end of the first inductor L1 is connected to the first output end of the switching circuit 11, that is, the first end of the first inductor L1 is connected to the second end of the first switch T1 and the second end of the second switch T2, respectively. The second end of the first inductor L1 is connected to the first electrode of the second switch Q2. The second electrode of the second switch Q2 is connected to the second electrode of the third switch Q3, and the first electrode of the third switch Q3 is connected to the neutral line N. Referring to Figure 4 , when the first end of the second switch T2 and the first end of the third switch T3 in the switching circuit 11 are both connected to the positive electrode Bat+ of the energy storage device 300, the first electrode of the first switch Q1 is connected to the negative bus -BUS, and the second electrode of the first switch Q1 is connected to the second end of the first inductor L1. The anode of the diode D is connected to the second end of the first inductor L1, and the cathode of the diode D is connected to the positive bus +BUS. 5 , when the first end of the second switch T2 and the first end of the third switch T3 in the switching circuit 11 are both connected to the negative electrode Bat- of the energy storage device 300, the first electrode of the first switch tube Q1 is connected to the second end of the first inductor L1, and the second electrode of the first switch tube Q1 is connected to the positive bus +BUS; the positive electrode of the diode D is connected to the negative bus -BUS, and the negative electrode of the diode D is connected to the second end of the first inductor L1. Specifically, when the positive electrode potential of the diode D is higher than the negative electrode potential, the diode D is turned on and can transmit current; when the positive electrode potential of the diode D is lower than the negative electrode potential, the diode D is turned off and cannot transmit current. The above-mentioned rectifier circuit 12 can operate in half-bridge mode.

[0069] Referring to Figures 4 and 5, in some embodiments of the present application, the charge-discharge circuit 14 may include: a second inductor L2, a fourth switch Q4, a fifth switch Q5, a first capacitor C11, and a second capacitor C12. The first end of the second inductor L2 is connected to the second output end of the switching circuit 11, that is, the first end of the second inductor L2 is connected to the second end of the third switch T3, and the second end of the second inductor L2 is connected to the first end of the fourth switch Q4 and the second end of the fifth switch Q5, respectively. The fourth switch Q4, the fifth switch Q5, the first capacitor C11, and the second capacitor C12 can form a low-power charge-discharge circuit 14 in a half-bridge topology. While its power is approximately only 30% of the full-power charge-discharge circuit 14, it can achieve the same performance as a full-power charge-discharge circuit 14 by operating at excess power for a short period of time, saving cost and circuit size compared to a full-power charge-discharge circuit 14. Specifically, the second end of the fourth switch Q4 is connected to the positive bus +BUS, and the first end of the fifth switch Q5 is connected to the negative bus -BUS. The first capacitor C11 is connected between the positive bus +BUS and the neutral line N, that is, the first capacitor C11 is arranged in parallel with the capacitor of the first bus 15. The second capacitor C12 is connected between the negative bus -BUS and the neutral line N, that is, the second capacitor C12 is arranged in parallel with the capacitor of the second bus 15. When the charge and discharge circuit 14 is used as a balancing circuit, when the controller determines that the voltage of the positive bus +BUS is higher than the voltage of the negative bus -BUS, it can control the fourth switch tube Q4 to turn on and the fifth switch tube Q5 to turn off, so that the voltage of the positive bus +BUS is released to the neutral line N; when the controller determines that the voltage of the negative bus -BUS is higher than the voltage of the positive bus +BUS, it can control the fifth switch tube Q5 to turn on and the fourth switch tube Q4 to turn off, so that the voltage of the negative bus -BUS is released to the neutral line N.

[0070] In the embodiments of the present application, the inverter circuit 13 may adopt a two-level half-bridge topology, a T-type or I-type three-level half-bridge topology, or other topologies. Referring to Figures 4 and 5 , taking the T-type three-level topology as an example, the inverter circuit 13 may include: a third inductor L3, a sixth switch Q6, a seventh switch Q7, an eighth switch Q8, and a ninth switch Q9. The first end of the sixth switch Q6 is connected to the neutral line N, and the second end of the sixth switch Q6 is connected to the second end of the seventh switch Q7. The first end of the third inductor L3 is connected to the first end of the seventh switch Q7, and the second end of the third inductor L3 is connected to the output terminal "Output" for supplying power to the load 400. Optionally, devices such as a fuse and a switch may be provided between the output terminal "Output" and the second end of the third inductor L3. The first end of the eighth switch Q8 is connected to the first end of the third inductor L3, and the second end of the eighth switch Q8 is connected to the positive bus +BUS. A first end of the ninth switch tube Q9 is connected to the negative bus -BUS, and a second end of the ninth switch tube Q9 is connected to a first end of the third inductor L3.

[0071] The switching tubes in the rectifier circuit 12, the inverter circuit 13, and the charge-discharge circuit 14 provided in the embodiments of the present application may include parallel diodes and transistors. Specifically, the switching tube may be a metal oxide semiconductor field effect transistor (MOSFET), which naturally has a reverse diode function. The switching tube may also be an insulated gate bipolar transistor (IGBT) or a bipolar junction transistor (BJT) with a built-in diode. The switching tube may also be an independent diode-parallel gallium nitride field effect transistor (GaN), a silicon carbide (SiC) power transistor, or one or more of various types of transistor devices, which are not listed one by one in the embodiments of the present application.

[0072] Specifically, each switch tube may include a first electrode, a second electrode, and a control electrode, wherein the control electrode is used to control the on / off state of the switch tube. When the switch tube is on, current can be transmitted between the first electrode and the second electrode of the switch tube. When the switch tube is off, current cannot be transmitted between the first electrode and the second electrode of the switch tube. Taking MOSFET as an example, the control electrode of the switch tube is the gate electrode, the first electrode of the switch tube can be the source electrode of the switch tube, and the second electrode can be the drain electrode of the switch tube. Alternatively, the first electrode can be the drain electrode of the switch tube, and the second electrode can be the source electrode of the switch tube.

[0073] FIG6 schematically shows another specific circuit structure diagram of the uninterruptible power supply provided in an embodiment of the present application, and FIG7 schematically shows another specific circuit structure diagram of the uninterruptible power supply provided in an embodiment of the present application.

[0074] 6 and 7 , in some other embodiments of the present application, the AC power connected to the uninterruptible power supply can also output three-phase AC power, such as phase A, phase B, and phase C. Correspondingly, the uninterruptible power supply may include three rectifier circuits and three inverter circuits corresponding to each phase of the three-phase AC power (i.e., phase A, phase B, and phase C). Each rectifier circuit is used to convert the received electrical energy of the energy storage device or the corresponding single-phase AC power (i.e., phase A, phase B, and phase C) into DC power and output it to the bus, and each inverter circuit is used to convert the DC power on the bus into AC power and supply power to the load. The rectifier circuit corresponding to phase A AC power may include a first inductor L1a, a first switching tube Q1a, a second switching tube Q2a, a third switching tube Q3a, and a diode Da; the rectifier circuit corresponding to phase B AC power may include a first inductor L1b, a first switching tube Q1b, a second switching tube Q2b, a third switching tube Q3b, and a diode Db; and the rectifier circuit corresponding to phase C AC power may include a first inductor L1c, a first switching tube Q1c, a second switching tube Q2c, a third switching tube Q3c, and a diode Dc. The inverter circuit corresponding to the A-phase AC power may include a third inductor L3a, a sixth switching transistor Q6a, a seventh switching transistor Q7a, an eighth switching transistor Q8a, and a ninth switching transistor Q9a. The inverter circuit corresponding to the B-phase AC power may include a third inductor L3b, a sixth switching transistor Q6b, a seventh switching transistor Q7b, an eighth switching transistor Q8b, and a ninth switching transistor Q9b. The inverter circuit corresponding to the C-phase AC power may include a third inductor L3c, a sixth switching transistor Q6c, a seventh switching transistor Q7c, an eighth switching transistor Q8c, and a ninth switching transistor Q9c. The topology of each rectifier circuit and each inverter circuit can refer to the topology of single-phase AC power and will not be described in detail here.

[0075] Correspondingly, the switching circuit may include three first switches T1a, T1b, and T1c, and three second switches T2a, T2b, and T2c, corresponding to each phase of the three-phase AC power (i.e., phase A, phase B, and phase C). The first end of the first switch T1a is used to receive the A-phase AC power, the second end of the first switch T1a is connected to the input end of the rectifier circuit corresponding to the A-phase AC power, and the second end of the second switch T2a is connected to the input end of the rectifier circuit corresponding to the A-phase AC power. The first end of the first switch T1b is used to receive the B-phase AC power, the second end of the first switch T1b is connected to the input end of the rectifier circuit corresponding to the B-phase AC power, and the second end of the second switch T2b is connected to the input end of the rectifier circuit corresponding to the B-phase AC power. The first end of the first switch T1c is used to receive the C-phase AC power, the second end of the first switch T1c is connected to the input end of the rectifier circuit corresponding to the C-phase AC power, and the second end of the second switch T2c is connected to the input end of the rectifier circuit corresponding to the C-phase AC power.

[0076] Taking the uninterruptible power supply 100 shown in FIG. 4 as an example, the working sequence of the uninterruptible power supply 100 provided in the embodiment of the present application in different modes and the working sequence controlled by the controller during mode switching are introduced below.

[0077] Figure 8a schematically shows a schematic diagram of the working principle of the rectifier circuit of the uninterruptible power supply provided in an embodiment of the present application in the mains power supply mode in the positive half-cycle, Figure 8b schematically shows a schematic diagram of the working principle of the rectifier circuit of the uninterruptible power supply provided in an embodiment of the present application in the mains power supply mode in the negative half-cycle, and Figure 8c schematically shows a schematic diagram of the working principle of the charging and discharging circuit of the uninterruptible power supply provided in an embodiment of the present application in the mains power supply mode.

[0078] When the AC power supply 200 is operating normally, the uninterruptible power supply 100 is in mains power supply mode. Referring to Figures 8a to 8c, the first switch T1 connects the AC power supply 200 and the rectifier circuit 12, the third switch T3 connects the positive electrode of the energy storage device 300 and the charge-discharge circuit 14, and the second switch T2 disconnects the positive electrode of the energy storage device 300 from the rectifier circuit 12. Referring to Figure 8a, during the positive half-cycle of the AC power supply, the second switch Q2 is in the on-state. When the third switch Q3 is off, the current flows through path ①; when the third switch Q3 is on, the current flows through path ②. Referring to Figure 8b, during the negative half-cycle of the AC power supply, the third switch Q3 is in the on-state. When the second switch Q2 is on, the current flows through path ①; when the second switch Q2 is off, the current flows through path ②. 8c, the fifth switch tube Q5 is in the off state. When the fourth switch tube Q4 is turned on, the current charges the energy storage device 300 through path ①; when the fourth switch tube Q4 is turned off, the current charges the energy storage device 300 through path ②.

[0079] Figure 9a schematically shows a schematic diagram of the working principle of the uninterruptible power supply provided in an embodiment of the present application, in which the charging and discharging circuit supplies power to the bus when the AC power supply fails. Figure 9b schematically shows a schematic diagram of the working principle of the uninterruptible power supply provided in an embodiment of the present application in an energy storage device power supply mode. Figure 9c schematically shows another schematic diagram of the working principle of the uninterruptible power supply provided in an embodiment of the present application in an energy storage device power supply mode. Figure 9d schematically shows a schematic diagram of the working principle of the charging and discharging circuit of the uninterruptible power supply provided in an embodiment of the present application as a bus balancing circuit in an energy storage device power supply mode.

[0080] When the AC power supply 200 fails, the uninterruptible power supply 100 will switch from the mains power supply mode to the energy storage device 300 power supply mode. Referring to Figure 9a, the charge and discharge circuit 14 can quickly switch from the charging state to the discharging state, discharge the electric energy stored in the energy storage device 300 to the bus 15, and quickly reverse the power supply to the bus 15. Specifically, when the fourth switch tube Q4 is in the off state and the fifth switch tube Q5 is turned off, the current is discharged through the ① path; when the fifth switch tube Q5 is turned on, the current is discharged through the ② path. During the period when the charge and discharge circuit 14 supplies power to the bus 15, the first switch T1 can switch the conduction state of the AC power supply 200 and the rectifier circuit 12 to the disconnection state, and then the second switch T2 switches the disconnection state of the energy storage device 300 and the rectifier circuit 12 to the conduction state, so that the uninterruptible power supply 100 starts to operate in the energy storage device 300 power supply mode. In the energy storage device 300 power supply mode, when the first switch Q1 is on, the current follows the path indicated by the arrow in Figure 9b. When the first switch Q1 is off, the current follows the path indicated by the arrow in Figure 9c. In the energy storage device 300 power supply mode, the fourth switch T4 can connect the neutral line N to the charge-discharge circuit 14, allowing the charge-discharge circuit 14 to function as a bus balancing circuit. Referring to Figure 9d, the operating principle of the bus balancing circuit is as follows: when the fourth switch Q4 is on and the fifth switch Q5 is off, the current flows through path ①. When the fourth switch Q4 is off and the fifth switch Q5 is on, the current flows through path ②.

[0081] When the AC power supply 200 returns to normal, the above-mentioned uninterruptible power supply 100 will switch from the energy storage device 300 power supply mode to the mains power supply mode. Referring to Figure 9a, the third switch T3 and the fourth switch T4 will switch from conducting the neutral line N and the charge-discharge circuit 14 to conducting the positive pole of the energy storage device 300 and the charge-discharge circuit 14. The charge-discharge circuit 14 can quickly switch to the discharge state, discharge the electric energy stored in the energy storage device 300 to the bus 15, and quickly reverse power the bus 15. During the period when the charge-discharge circuit 14 supplies power to the bus 15, the second switch T2 switches the conduction state of the energy storage device 300 and the rectifier circuit 12 to the disconnection state. After that, the first switch T1 can switch the disconnection state of the AC power supply 200 and the rectifier circuit 12 to the conduction state, so that the uninterruptible power supply 100 starts to operate in the mains power supply mode. The working principle of AC power supplying the bus 15 through the rectifier circuit 12 is shown in Figures 8a and 8b. The working principle of the charge-discharge circuit 14 charging the energy storage device 300 is shown in FIG8 c .

[0082] Based on the same inventive concept, an embodiment of the present application also provides a power supply system, including the above-mentioned uninterruptible power supply and energy storage device provided in the embodiment of the present application. Among them, the energy storage device can be connected to the first end of the second switch in the uninterruptible power supply. Specifically, the power supply system is connected between the AC power supply and the power-consuming equipment, and the power supply system is used to power the power-consuming equipment through the AC power output by the AC power supply. When applied to a small power supply system, the energy storage device can be built into the UPS or externally placed outside the UPS. When applied to medium and large power supply systems, the energy storage device is large in size and is generally placed outside the UPS. Since the principle of solving the problem of this power supply system is similar to that of the aforementioned uninterruptible power supply, the implementation of this power supply system can refer to the implementation of the aforementioned uninterruptible power supply, and the repeated parts will not be repeated.

[0083] Obviously, those skilled in the art may make various modifications and variations to this application without departing from the scope of protection of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is intended to include these modifications and variations.

Claims

1. An uninterruptible power supply, characterized in that: include: Mains input terminal, switching circuit, rectification circuit, inverter circuit and charging and discharging circuit; The switching circuit includes: a first switch, a second switch and a third switch; the first end of the first switch is connected to the mains input end, and the second end of the first switch is connected to the input end of the rectifier circuit; the first end of the second switch is used to connect the energy storage device, and the second end of the second switch is connected to the input end of the rectifier circuit; the first end of the third switch is used to connect the energy storage device, and the second end of the third switch is connected to the first end of the charge and discharge circuit; The output end of the rectifier circuit is used to connect to the bus, the input end of the inverter circuit is used to connect to the bus, and the second end of the charge-discharge circuit is used to connect to the bus; The uninterruptible power supply further comprises a controller, wherein the controller is configured to: In response to the AC power inputted from the mains input terminal being normal, controlling the first switch to be turned on, the second switch to be turned off, and the third switch to be turned on, and controlling the rectifier circuit to convert the AC power inputted from the mains input terminal into DC power, controlling the inverter circuit to convert the DC power into AC power and provide it to a load, and controlling the charge-discharge circuit to charge the energy storage device; In response to a fault in the alternating current input to the mains input terminal, the charge-discharge circuit is controlled to discharge the electric energy stored in the energy storage device to the bus. After the charge-discharge circuit discharges the electric energy stored in the energy storage device to the bus, the first switch is controlled to be disconnected, the second switch is controlled to be turned on, and the third switch is controlled to be disconnected, so that the electric energy output by the energy storage device is input to the rectifier circuit. The rectifier circuit is also used to convert the electric energy input by the energy storage device into power and output it to the bus.

2. The uninterruptible power supply according to claim 1, characterized in that: The busbar includes a positive busbar and a negative busbar; the switching circuit also includes a fourth switch, a first end of the fourth switch is used to connect the neutral line, and a second end of the fourth switch is connected to the first end of the charging and discharging circuit; The controller is also used for: In response to a fault in the alternating current inputted into the mains input terminal, the fourth switch is controlled to be turned on while the third switch is controlled to be turned off, and the conduction of the switch tube in the charge and discharge circuit is controlled so that the voltage on the bus with a higher voltage among the positive bus and the negative bus is released to the neutral line.

3. The uninterruptible power supply according to claim 2, characterized in that: The third switch and the fourth switch constitute a single-pole double-throw switch.

4. The uninterruptible power supply according to claim 2 or 3, characterized in that: The controller is also used for: In response to the AC power inputted from the mains input terminal returning to normal, the fourth switch is controlled to be disconnected and the third switch is controlled to be turned on, and the charge-discharge circuit is controlled to discharge the electric energy stored in the energy storage device to the bus. After the charge-discharge circuit discharges the electric energy stored in the energy storage device to the bus, the second switch is controlled to be disconnected and the first switch is controlled to be turned on, so that the AC power inputted from the mains input terminal is converted into DC power by the rectifier circuit to supply power to the bus, and the charge-discharge circuit is controlled to charge the energy storage device.

5. The uninterruptible power supply according to claim 4, characterized in that: During the period when the charge-discharge circuit discharges the electric energy stored in the energy storage device to the bus, the actual discharge power of the charge-discharge circuit is greater than twice the rated discharge power of the charge-discharge circuit.

6. The uninterruptible power supply according to any one of claims 1 to 5, characterized in that: The first end of the second switch and the first end of the third switch are both used to connect the positive electrode of the energy storage device, and the negative electrode of the energy storage device is connected to the negative busbar among the busbars; The rectifier circuit includes: a first inductor, a first switch tube, a second switch tube, a third switch tube and a diode; The first end of the first inductor is connected to the second end of the first switch and the second end of the second switch respectively, and the second end of the first inductor is connected to the second electrode of the first switch tube, the anode of the diode and the first electrode of the second switch tube respectively; The first electrode of the first switch tube is connected to the negative bus, and the cathode of the diode is connected to the positive bus among the bus; The second electrode of the second switch tube is connected to the second electrode of the third switch tube, and the first electrode of the third switch tube is connected to the neutral line.

7. The uninterruptible power supply according to any one of claims 1 to 5, characterized in that: The first end of the second switch and the first end of the third switch are both used to connect the negative electrode of the energy storage device, and the positive electrode of the energy storage device is connected to the positive busbar in the busbars; The rectifier circuit includes: a first inductor, a first switch tube, a second switch tube, a third switch tube and a diode; The first end of the first inductor is connected to the second end of the first switch and the second end of the second switch respectively, and the second end of the first inductor is connected to the first electrode of the first switch tube, the cathode of the diode and the first electrode of the second switch tube respectively; The second electrode of the first switch tube is connected to the positive bus, and the positive electrode of the diode is connected to the negative bus in the bus; The second electrode of the second switch tube is connected to the second electrode of the third switch tube, and the first electrode of the third switch tube is connected to the neutral line.

8. The uninterruptible power supply according to any one of claims 1 to 7, characterized in that: The charging and discharging circuit comprises: a second inductor, a fourth switch tube, a fifth switch tube, a first capacitor and a second capacitor; The first end of the second inductor is connected to the second end of the third switch, and the second end of the second inductor is respectively connected to the first end of the fourth switch tube and the second end of the fifth switch tube; The second end of the fourth switch tube is connected to the positive bus bar among the bus bars, and the first end of the fifth switch tube is connected to the negative bus bar among the bus bars; The first capacitor is connected between the positive bus and the neutral line, and the second capacitor is connected between the negative bus and the neutral line.

9. The uninterruptible power supply according to claim 2, characterized in that: The charging and discharging circuit comprises: a second inductor, a fourth switch tube, a fifth switch tube, a first capacitor and a second capacitor; The first end of the second inductor is connected to the second end of the third switch, and the second end of the second inductor is respectively connected to the first end of the fourth switch tube and the second end of the fifth switch tube; The second end of the fourth switch tube is connected to the positive bus bar among the bus bars, and the first end of the fifth switch tube is connected to the negative bus bar among the bus bars; The first capacitor is connected between the positive bus and the neutral line, and the second capacitor is connected between the negative bus and the neutral line; In response to the voltage of the positive bus being higher than the voltage of the negative bus, the controller is used to control the fourth switch tube in the charge and discharge circuit to be turned on and the fifth switch tube to be turned off; or, In response to the voltage of the negative bus being higher than the voltage of the positive bus, the controller is used to control the fifth switch tube in the charge and discharge circuit to be turned on and the fourth switch tube to be turned off.

10. The uninterruptible power supply according to any one of claims 1 to 9, characterized in that: If three-phase AC power is input to the mains input terminal, the uninterruptible power supply includes three rectifier circuits and three inverters corresponding to each phase of the three-phase AC power; the switching circuit includes three first switches and three second switches corresponding to each phase of the three-phase AC power; The first end of each first switch is used to receive a corresponding one-phase alternating current, the second end of each first switch is connected to the input end of the rectifier circuit corresponding to the same-phase alternating current, and the second end of each second switch is connected to the input end of the rectifier circuit corresponding to the same-phase alternating current; Each of the rectifier circuits is used to convert the received electric energy of the energy storage device or the corresponding one-phase alternating current into direct current and output it to the bus.

11. A power supply system, characterized in that: The power supply system includes an energy storage device and an uninterruptible power supply; The uninterruptible power supply comprises: a mains input terminal, a switching circuit, a rectifier circuit, an inverter circuit and a charge-discharge circuit; The switching circuit includes: a first switch, a second switch and a third switch; a first end of the first switch is connected to the mains input end, and a second end of the first switch is connected to the input end of the rectifier circuit; a first end of the second switch is connected to the energy storage device, and a second end of the second switch is connected to the input end of the rectifier circuit; a first end of the third switch is connected to the energy storage device, and a second end of the third switch is connected to the first end of the charge and discharge circuit; The output end of the rectifier circuit is used to connect to the bus, the input end of the inverter circuit is used to connect to the bus, and the second end of the charge-discharge circuit is used to connect to the bus; The uninterruptible power supply further comprises a controller, wherein the controller is configured to: In response to the AC power input from the mains input terminal being normal, the first switch is controlled to be turned on, the second switch is turned off, and the third switch is controlled to be turned on, and the rectifier circuit is controlled to convert the AC power input from the mains input terminal into DC power, and the inverter circuit is controlled to convert the AC power input from the mains input terminal into DC power. The direct current is converted into alternating current and provided to a load, and the charging and discharging circuit is controlled to charge the energy storage device; In response to a fault in the alternating current input to the mains input terminal, the charge-discharge circuit is controlled to discharge the electric energy stored in the energy storage device to the bus. After the charge-discharge circuit discharges the electric energy stored in the energy storage device to the bus, the first switch is controlled to be disconnected, the second switch is controlled to be turned on, and the third switch is controlled to be disconnected, so that the electric energy output by the energy storage device is input to the rectifier circuit. The rectifier circuit is also used to convert the electric energy input by the energy storage device into power and output it to the bus.

12. The power supply system according to claim 11, characterized in that: The busbar includes a positive busbar and a negative busbar; the switching circuit also includes a fourth switch, a first end of the fourth switch is used to connect the neutral line, and a second end of the fourth switch is connected to the first end of the charging and discharging circuit; The controller is also used for: In response to a fault in the alternating current inputted into the mains input terminal, the fourth switch is controlled to be turned on while the third switch is controlled to be turned off, and the conduction of the switch tube in the charge and discharge circuit is controlled so that the voltage on the bus with a higher voltage among the positive bus and the negative bus is released to the neutral line.

13. The power supply system according to claim 11 or 12, characterized in that: The controller is also used for: In response to the AC power inputted from the mains input terminal returning to normal, the fourth switch is controlled to be disconnected and the third switch is controlled to be turned on, and the charge-discharge circuit is controlled to discharge the electric energy stored in the energy storage device to the bus. After the charge-discharge circuit discharges the electric energy stored in the energy storage device to the bus, the second switch is controlled to be disconnected and the first switch is controlled to be turned on, so that the AC power inputted from the mains input terminal is converted into DC power by the rectifier circuit to supply power to the bus, and the charge-discharge circuit is controlled to charge the energy storage device.

14. The power supply system according to any one of claims 11 to 13, characterized in that: The charging and discharging circuit comprises: a second inductor, a fourth switch tube, a fifth switch tube, a first capacitor and a second capacitor; The first end of the second inductor is connected to the second end of the third switch, and the second end of the second inductor is respectively connected to the first end of the fourth switch tube and the second end of the fifth switch tube; The second end of the fourth switch tube is connected to the positive bus bar among the bus bars, and the first end of the fifth switch tube is connected to the negative bus bar among the bus bars; The first capacitor is connected between the positive bus and the neutral line, and the second capacitor is connected between the negative bus and the neutral line.

15. The power supply system according to claim 12, characterized in that: The charging and discharging circuit comprises: a second inductor, a fourth switch tube, a fifth switch tube, a first capacitor and a second capacitor; The first end of the second inductor is connected to the second end of the third switch, and the second end of the second inductor is respectively connected to the first end of the fourth switch tube and the second end of the fifth switch tube; The second end of the fourth switch tube is connected to the positive bus bar among the bus bars, and the first end of the fifth switch tube is connected to the negative bus bar among the bus bars; The first capacitor is connected between the positive bus and the neutral line, and the second capacitor is connected between the negative bus and the neutral line; In response to the voltage of the positive bus being higher than the voltage of the negative bus, the controller is used to control the fourth switch tube in the charge and discharge circuit to be turned on and the fifth switch tube to be turned off; or, In response to the voltage of the negative bus being higher than the voltage of the positive bus, the controller is used to control the fifth switch tube in the charge and discharge circuit to be turned on and the fourth switch tube to be turned off.

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