CN220291718U - Uninterruptible power supply and power supply system - Google Patents

Abstract

An uninterruptible power supply and a power supply system are used for realizing normal starting of the uninterruptible power supply and safety of a switching device. The uninterrupted power supply comprises a first rectifying circuit, a charging and discharging circuit, a bus capacitor, a first switching circuit and a second rectifying circuit; the first rectifying circuit is connected with the charge-discharge circuit and is used for rectifying the voltage output by the alternating current power supply; the charging and discharging circuit is connected with the bus capacitor, and the voltage output by the first rectifying circuit is boosted and then charges the bus capacitor until the voltages at two ends of the bus capacitor are charged to a first voltage; the first switch circuit is connected with the second rectifying circuit and is used for controlling the connection of the alternating current power supply and the second rectifying circuit. The uninterrupted power supply can perform boosting operation through the charging and discharging circuit to reduce the pressure difference between the alternating current power supply and the bus capacitor, and at the moment, the first switching circuit is controlled to be conducted, so that the normal starting of the uninterrupted power supply can be realized, and the safety of the first switching circuit is protected.

Description

Uninterruptible power supply and power supply system

Technical Field

The present application relates to the field of power, and in particular, to an uninterruptible power supply and a power supply system.

Background

An uninterruptible power supply (uninterruptible power system, UPS) is a device that can replace the grid to uninterruptedly supply power to a load and maintain the load in normal operation in the event of a grid fault. Specifically, the uninterruptible power supply is respectively connected with the power grid and the load, so that the working state of the power grid can be monitored, and when the power grid works normally, the uninterruptible power supply can supply power to the load by utilizing the electric energy provided by the power grid; when the power grid fails, the uninterruptible power supply can control the internal configured battery pack to discharge, and the electric energy output by the battery pack is used for continuously supplying power to the load.

And a bus capacitor is arranged in the uninterruptible power supply, when the uninterruptible power supply is connected with the power grid for the first time or the power grid fault removal is connected with the uninterruptible power supply in a recovery way, the voltage at two ends of the bus capacitor is approximately equal to zero, and the voltage difference value between the bus capacitor and the power grid voltage is overlarge.

In order to improve the power supply safety, before the uninterruptible power supply supplies power to a load, a rectifying circuit in the uninterruptible power supply or a special rectifying circuit is configured to precharge a bus capacitor, so that the starting of the uninterruptible power supply is generally realized. When in actual use, the electric energy transmitted on the power grid is generally converted into direct-current electric energy through the uncontrollable switching device and charges the bus capacitor, so that the pre-charging voltage of the bus capacitor is limited by the voltage amplitude of the power grid, when the power grid is formally connected into the uninterruptible power supply after the charging is finished, the fluctuation of the output voltage of the power grid and the power supply of the load inside the uninterruptible power supply can cause overlarge voltage difference between the voltage of the bus capacitor and the voltage of the power grid, the starting failure is caused, the contact of the switching device between the uninterruptible power supply and the power grid is adhered, the connection between the uninterruptible power supply and the power grid cannot be disconnected, and the uninterruptible power supply is damaged.

Disclosure of Invention

The utility model provides an uninterrupted power source and power supply system for guarantee uninterrupted power source can normally realize starting, and guarantee switching element's safety.

The specific technical scheme provided by the embodiment of the application is as follows:

in a first aspect, the present application provides an uninterruptible power supply, where the uninterruptible power supply at least includes: the device comprises a first rectifying circuit, a bus capacitor, a second rectifying circuit, a first switch circuit, a charging and discharging circuit and the like. The first rectifying circuit is connected with the charge-discharge circuit and is used for being connected with an alternating current power supply; the charging and discharging circuit is connected with the bus capacitor, and the first switching circuit is connected with the second rectifying circuit and is used for being connected with an alternating current power supply.

In practical application, the battery pack is generally configured in the uninterruptible power supply or connected with the battery pack, and the charging and discharging circuit is connected between the battery pack and the bus capacitor and is used for charging or discharging the battery pack, so that the load is continuously supplied with power after the AC power supply fails, and the continuous power supply function of the uninterruptible power supply is realized. The charging and discharging circuit has a voltage regulating function, when the alternating current power supply is connected, in order to reduce the pressure difference between the bus capacitor and the alternating current power supply and realize safe starting of the uninterrupted power supply, the alternating current power supply can utilize the voltage regulating function of the charging and discharging circuit and the rectifying function of the first rectifying circuit to rectify and regulate the electric energy output by the alternating current power supply and charge the bus capacitor until the bus capacitor is charged to the first voltage. The charging voltage of the bus capacitor is obtained by boosting the charging and discharging circuit, so that the charging voltage of the bus capacitor is not limited by the voltage amplitude of the alternating current power supply, voltage drop caused by the operation of an internal load of the uninterrupted power supply and voltage fluctuation of the alternating current power supply can be compensated, the first switching circuit is controlled to be conducted, the second rectifying circuit is controlled to be operated, the uninterrupted power supply can be normally started and supply power for the load connected with the bus capacitor, and the safety of the first switching circuit is ensured.

In one possible design, a battery pack may be disposed inside the ups, and the battery pack is connected to the charge-discharge circuit, and is configured to output the stored voltage to the charge-discharge circuit; the charge-discharge circuit is also used for: and carrying out boosting treatment on the voltage output by the battery pack, and then charging the bus capacitor until the voltages at two ends of the bus capacitor are charged to the first voltage.

By adopting the uninterruptible power supply, when the electric energy is stored in the battery pack, the charging and discharging circuit can boost the electric energy stored in the battery pack and precharge the bus capacitor, so that the flexibility selection of the precharge mode of the bus capacitor is realized.

In one possible implementation, the uninterruptible power supply further includes a second switching circuit connected between the battery pack and the charge-discharge circuit, and a third switching circuit connected between the first rectifying circuit and the charge-discharge circuit. The second switch circuit can control connection of the battery pack and the charging and discharging circuit, and the third switch circuit can control connection of the first rectifying circuit and the charging and discharging circuit.

By adopting the uninterruptible power supply, the second switch circuit is connected between the battery pack and the charging and discharging circuit, and when the second switch circuit is conducted, a charging loop between the battery pack and the bus capacitor can be formed. The third switch circuit is connected between the first rectifying circuit and the charging and discharging circuit, and when the third switch circuit is conducted, a charging loop between the first rectifying circuit and the bus capacitor can be formed. Accordingly, the precharge path of the bus capacitor can be selected by controlling the conduction of the second switch circuit and the third switch circuit.

In one possible implementation manner, the uninterruptible power supply further includes a first controller, and the first controller is connected with the charging and discharging circuit and is used for controlling the charging and discharging circuit to boost the voltage output by the battery pack or the first rectifying circuit and then charge the bus capacitor.

In one possible implementation, the first controller is further connected to the first switch circuit, the second switch circuit, and the third switch circuit, for controlling the conduction of the first switch circuit, the second switch circuit, and the third switch circuit.

In one possible implementation, the uninterruptible power supply further includes a second controller, connected to the first switch circuit, the second switch circuit, and the third switch circuit, for controlling conduction of the first switch circuit, the second switch circuit, and the third switch circuit.

In one possible implementation, the uninterruptible power supply further includes a voltage sensor coupled to the bus capacitor for detecting a voltage across the bus capacitor.

In one possible implementation manner, if the uninterruptible power supply is connected with an ac load, in order to supply power to the ac load, the uninterruptible power supply may further include an inverter circuit connected with the bus capacitor, and configured to convert a voltage across the bus capacitor into a supply voltage of the load connected to the rear end, and supply power to the load.

In a second aspect, embodiments of the present application provide a power supply system that may include a power source, an ac power source, and an uninterruptible power supply provided in the first aspect of the embodiments of the present application.

The uninterruptible power supply is respectively connected with the load and the alternating current power supply and is used for converting the voltage output by the alternating current power supply into the power supply voltage of the load and supplying power to the load, and when the power supply fails, the electric energy stored by the battery pack is converted into the power supply voltage of the load and supplies power to the load.

In addition, the technical effects caused by any possible implementation manner of the second aspect may refer to the technical effects caused by different implementation manners in the first aspect of the embodiments of the present application, which are not described herein.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the description of the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic structural diagram of an uninterruptible power supply according to an embodiment of the present application;

Fig. 2 is a schematic structural diagram of a uninterruptible power supply according to an embodiment of the present disclosure;

fig. 3 is a schematic structural diagram of a first rectifying circuit according to an embodiment of the present disclosure;

fig. 4 is a schematic structural diagram of a second rectifying circuit according to an embodiment of the present disclosure;

fig. 5 is a schematic structural diagram of a bus capacitor according to an embodiment of the present application;

fig. 6 is a schematic structural diagram of a charge-discharge circuit according to an embodiment of the present disclosure;

fig. 7 is a schematic structural diagram of a first switching circuit according to an embodiment of the present application;

fig. 8 is a schematic structural diagram of a second switching circuit and a third switching circuit according to an embodiment of the present application.

Detailed Description

Embodiments of the present application will be described in detail below with reference to the accompanying drawings.

The terminology used in the description section of the present application is for the purpose of describing particular embodiments of the present application only and is not intended to be limiting of the present application. It will be apparent that the described embodiments are merely some, but not all embodiments of the present application. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present disclosure.

It should be noted that the terms "first," "second," and the like in the description and claims of the present application and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that embodiments of the present application described herein may be implemented in sequences other than those illustrated or otherwise described herein. The implementations described in the following exemplary examples are not representative of all implementations consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with some aspects of the present application as detailed in the accompanying claims.

In the following, some terms in the embodiments of the present application are explained for easy understanding by those skilled in the art.

(1) The term "plurality" in the embodiments of the present application means two or more, and other adjectives are similar thereto.

(2) The controllable switching device in this embodiment of the present application refers to a device in which on or off of a switch can be controlled by an electrical signal, for example, the controllable switching device may be one or more of a relay, a metal oxide semiconductor field effect transistor (metal oxide semiconductor field effect transistor, MOSFET), a bipolar junction transistor (bipolar junction transistor, BJT), an insulated gate bipolar transistor (insulated gate bipolar transistor, IGBT), a silicon carbide (SiC) transistor, a silicon controlled rectifier (silicon controlled rectifier, SCR), and other types of switching transistors, which are not further listed in this embodiment of the present application. The package form of each switch tube can be single tube package or multi-tube package, and the embodiment of the application does not limit the package form. Each switching tube can comprise a first end, a second end and a control end, wherein the control end is used for controlling the on or off of the switching tube. When the switching tube is turned on, current can be transmitted between the first end and the second end of the switching tube, and when the switching tube is turned off, current cannot be transmitted between the first end and the second end of the switching tube. Taking a MOSFET as an example, the control end of the switching tube is a gate, the first end of the switching tube may be a source, the second end may be a drain, or the first end may be a drain, and the second end may be a source.

It should be noted that, SCR can only realize unidirectional transmission of current, and unidirectional transmission of current can only be realized when no diode is configured at two ends of MOSFET, so two SCR or two MOSFET are generally adopted to realize bidirectional transmission of current.

(3) The uncontrollable switching device in the embodiment of the application refers to a device of which on or off of a switch cannot be controlled by an electrical signal, for example, one or more of various types of switching transistors such as a voltage regulator tube, a rectifier diode and the like.

(4) "connected" in embodiments of the present application may be understood as electrically connected or communicatively connected. The electrical connection of two electrical components may be a direct or indirect connection between two electrical components. For example, a may be directly connected to B, or indirectly connected to B through one or more other electrical components, for example, a may be directly connected to B, or directly connected to C, and C may be directly connected to B, where a and B are connected through C. The communication connection of the two electrical components is a wireless connection between the two electrical components, i.e. an electromagnetic connection of the two electrical components.

(5) Direct current and alternating current. Direct current in the embodiments of the present application refers to an electrical form in which electrical energy is conducted in a constant direction in a circuit. The direction of conduction of electrical energy is also referred to as the phase, and the phase of direct current may include both positive and negative directions. The power intensity of most direct current is fixed, and in some special direct current (such as pulse direct current), the power intensity also changes with time. The power strength is also referred to as the current amplitude. Common dc power sources include dry cell batteries, accumulators or dc generators, etc. Alternating current in embodiments of the present application refers to an electrical form in which electrical energy is conducted in a periodically varying direction in an electrical circuit. The power strength of most ac power also varies periodically over time. The periodic variation of the alternating current in the direction of conduction is defined by the frequency of the alternating current. The alternating current power changes the conduction direction faster as the frequency of the alternating current is larger, and the alternating current power changes the conduction direction slowly as the frequency of the alternating current is smaller. Common ac power sources include utility power, industrial and agricultural power sources, residential power sources, and the like.

(6) The "transformation ratio" of the circuit in the embodiment of the present application refers to a ratio between an input voltage and an output voltage of the circuit, and if the circuit performs a boosting process, a voltage amplitude of the input voltage is smaller than a voltage amplitude of the output voltage. If the circuit performs the step-down process, the voltage amplitude of the input voltage is greater than the voltage amplitude of the output voltage.

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. The scheme provided by the embodiment of the application is applied to equipment which needs to be maintained for a period of time to supply power when the power supply is disconnected. For example, when a data center is suddenly powered off, in order to prevent loss of important data, an uninterruptible power supply is generally configured in the data center, the uninterruptible power supply can supply power when a power grid or other power supply fails, and the data center can complete storage of the important data at the power supply time.

Wherein the above-described devices include, but are not limited to: vehicles, robots, lighting, industrial equipment, intelligent factory equipment, etc. Vehicles provided by embodiments of the present application may include one or more different types of vehicles or movable objects that operate or move on land (e.g., highways, roads, railways, etc.), on water (e.g., waterways, rivers, oceans, etc.), or spatially. For example, the vehicle may include a train, subway, aircraft, ship, aircraft, or other type of vehicle or movable object, and the like.

The embodiment of the application provides an uninterruptible power supply and a power supply system, which are used for ensuring that the uninterruptible power supply can normally realize starting and protecting the safety of the uninterruptible power supply.

The inventive concepts of the present application can be summarized as follows: the charging and discharging circuit can perform boosting treatment to precharge the bus capacitor, and the voltage fluctuation of the alternating current power supply and the voltage drop of the bus capacitor caused by internal load power supply are compensated by increasing the precharge voltage of the bus capacitor, so that the voltage drop between the alternating current power supply and the bus capacitor is reduced, successful starting of the uninterrupted power supply is ensured, and the safety of the device of the first switching circuit is protected.

Referring to fig. 1, the uninterruptible power supply according to the embodiment of the present application includes at least a first rectifying circuit, a charging/discharging circuit, a bus capacitor, a first switching circuit and a second rectifying circuit.

It should be understood that the uninterruptible power supply shown in fig. 1 is only one example, and that the uninterruptible power supply may have more or fewer components than shown in fig. 1, may combine two or more components, or may have a different configuration of components. The various components shown in the figures may be implemented in hardware, software, or a combination of hardware and software, including one or more signal processing and/or application specific integrated circuits.

The input end of the second rectifying circuit is connected with the alternating current power supply through the first switch circuit, and the output end of the second rectifying circuit is connected with the bus capacitor. The second rectifying circuit can convert alternating current output by the alternating current power supply into direct current, and the direct current is stabilized through the bus capacitor to supply power for a load connected with the rear end. Uninterruptible power supplies are typically configured with or connected to a battery pack that is connected to a bus capacitor through a charge and discharge circuit. The charging and discharging circuit can have a charging function and a discharging function, when the alternating current power supply can normally output electric energy, one end of the charging and discharging circuit, which is connected with the bus capacitor, is an input end, one end of the charging and discharging circuit, which is connected with the battery pack, is an output end, and the charging and discharging circuit performs charging treatment, converts the voltage of the bus capacitor into the charging voltage of the battery pack and charges the battery pack. When the AC power supply fails, one end of the charge-discharge circuit connected with the battery pack is an input end, one end of the charge-discharge circuit connected with the bus capacitor is an output end, the charge-discharge circuit can perform discharge treatment, the electric energy stored by the battery pack is converted and then is output to the bus capacitor, and the load is powered after being stabilized by the bus capacitor, so that the power supply requirement of the load connected with the uninterrupted power supply is met.

Wherein the ac power source may be a power grid or other power source, which may be, but is not limited to: urban grids, micro grids, household grids, industrial grids, and the like. Other power sources may be, but are not limited to: new energy power generation systems, diesel generators, and the like.

In practical application, the second rectifying circuit comprises a plurality of switching devices, the switching devices can be controllable switching devices or uncontrollable switching devices, and before the second rectifying circuit works, electric energy is stored in a bus capacitor inside the uninterruptible power supply and can be used for supplying power to a control device of the controllable switching devices.

Referring to fig. 1, the second rectifying circuit is connected to an ac power supply through a first switching circuit, which can control connection of the uninterruptible power supply to an external ac power supply. When the alternating current power supply fails, the first switch circuit can disconnect the uninterrupted power supply from the alternating current power supply in order to avoid that the normal operation of the uninterrupted power supply is affected by the failure of the alternating current power supply. When the AC power source is out of order, the first switch circuit can restore the connection between the uninterrupted power source and the AC power source, and ensure the normal operation of the uninterrupted power source.

In practical application, when the ac power source is recovered from a fault or the ups is first installed, the voltage at two ends of the bus capacitor is approximately equal to zero, if the first switch circuit is directly controlled to be turned on, the contact adhesion of the switching device inside the first switch circuit and the failure of the ups may be caused due to the overlarge voltage difference between the ac power source and the bus capacitor. In order to reduce the voltage difference between the alternating current power supply and the bus capacitor, the uninterruptible power supply provided by the embodiment of the application can precharge the bus capacitor through the first rectifying circuit and the charging and discharging circuit.

Specifically, the input end of the first rectifying circuit is used for being connected with an alternating current power supply, and the output end of the first rectifying circuit is connected with a bus capacitor through a charging and discharging circuit. When the AC power source is in fault elimination or the uninterrupted power source is installed for the first time, the first rectifying circuit can take electricity from the AC power source, rectifies the voltage output by the AC power source and outputs the rectified voltage to the charging and discharging circuit, the charging and discharging circuit carries out pre-charging on the bus capacitor after boosting the voltage output by the first rectifying circuit, and when the voltage at two ends of the bus capacitor is charged to the first voltage, the charging of the bus capacitor is stopped. The first voltage can be larger than or equal to the peak value of the alternating current power supply, so that voltage drop caused by voltage fluctuation of the alternating current power supply and internal devices is compensated, the pressure difference between the alternating current power supply and the bus capacitor is reduced, at the moment, the first switching circuit is controlled to be closed, the second rectifying circuit is controlled to operate, and normal operation of the uninterrupted power supply can be realized.

In practical application, a plurality of switching devices are arranged in the charging and discharging circuit, and when the charging and discharging circuit boosts the electric energy output by the first rectifying circuit, the conversion ratio of the charging and discharging circuit can be adjusted by adjusting the on or off of the switching devices, so that the charging voltage of the bus capacitor can be adjusted. By adopting the pre-charging mode of the bus capacitor, the charging voltage of the bus capacitor is not limited by the amplitude of the alternating current power supply, so that the pressure difference between the bus capacitor and the alternating current power supply after the charging is finished is reduced, and the uninterrupted power supply is ensured to be started successfully.

In one example, a voltage drop generated by the internal load power supply may be determined based on a parameter of the internal load of the uninterruptible power supply, and a voltage magnitude of the first voltage may be determined based on the voltage drop. The load may be a load that needs to be powered during the starting process of the ups, for example: an auxiliary source of the charge-discharge circuit and a controller of the charge-discharge circuit. The parameters may be, but are not limited to, the rated power of the load and the voltage drop generated across the internal circuit.

In one example, a sensor may be provided in the ups or connected to an external sensor that is connected to the ac power source and may monitor the voltage amplitude variation of the ac power source. Therefore, the voltage amplitude of the first voltage can be determined according to the voltage amplitude change condition of the alternating current power supply and the parameters of the internal load of the uninterruptible power supply.

During practical application, the uninterrupted power source that this application embodiment provided carries out the processing of stepping up through charge-discharge circuit and is precharged for the bus-bar capacitance, because charge-discharge circuit still is connected with the group battery, and the group battery can carry out electric energy storage, consequently, can also utilize the electric energy that the group battery stored to precharge for the bus-bar capacitance in this application embodiment, and the mode of precharging for the bus-bar capacitance is explained in detail in the following with the embodiment.

In one embodiment, a battery pack pre-charges a bus capacitor through a charge-discharge circuit

The battery pack is connected with the bus capacitor through the charging and discharging circuit, and the battery pack can obtain electric energy required by pre-charging of the bus capacitor from an external power supply.

In an example, a plurality of devices in the uninterruptible power supply can be connected through a power line and an interface, so that the battery pack after the pre-charging is completed can be connected with a charging and discharging circuit through a corresponding interface, and charging electric energy is provided for the bus capacitor.

In another example, the battery pack in the uninterruptible power supply can also be connected with other external power supplies, and the other external power supplies can charge the battery pack, so that the charged battery pack can meet the pre-charging requirement of the bus capacitor.

In a second embodiment, the ac power source precharges the bus capacitor

If the electric energy stored in the battery pack in the uninterruptible power supply is insufficient or the battery pack cannot be charged in advance, the alternating current power supply can be used as a charging source of the bus capacitor, the first rectifying circuit can be connected with an external alternating current power supply through a power line and an interface, and electricity is taken from an alternating current unit, and the obtained electric energy is sequentially subjected to rectifying treatment by the first rectifying circuit and boosting treatment by the charging and discharging circuit and then is output to the bus capacitor to precharge the bus capacitor.

In an example, a plurality of switching devices are disposed in the first rectifying circuit, and if no electric energy is stored in the bus capacitor and the battery pack, the switching devices in the first rectifying circuit are uncontrollable switching devices in order to avoid that the controllable switching devices cannot work due to power failure of the control devices.

In another example, the first rectifying circuit is provided with a plurality of switching devices, and if the battery pack or the bus capacitor in the uninterruptible power supply stores electric energy, the switching devices in the first rectifying circuit may be controllable switching devices or uncontrollable switching devices.

In practical application, the first rectifying circuit obtains electric energy from an alternating current power supply and precharges the bus capacitor, and in order to prevent large impact current in the circuit, a current limiting resistor is configured in the first rectifying circuit and used for reducing the current amplitude output by the first rectifying circuit.

As can be seen from the foregoing description, the bus capacitor may be precharged in two manners, the two precharge manners correspond to the two charging power sources respectively, and are a battery pack and an ac power source respectively. When the third switch circuit is conducted, the battery pack can be connected with the bus capacitor through the charging and discharging circuit and forms a pre-charging loop of the bus capacitor. When the third switch circuit is conducted, the first rectifying circuit can be connected with the bus capacitor through the charging and discharging circuit and forms a pre-charging loop of the bus capacitor. Therefore, the precharge mode of the bus capacitor can be selected by controlling the conduction of the second switch circuit and the third switch circuit.

In practical application, in order to control the precharge time of the bus capacitor, a sensor may be configured in the uninterruptible power supply or connected with an external sensor, where the sensor may detect voltages at two ends of the bus capacitor, and control the charge-discharge circuit to be the precharge end time of the bus capacitor according to the voltages at two ends of the bus capacitor.

The following describes the precharge process and the operation process of the bus capacitor in detail by the structure of a plurality of devices in the uninterruptible power supply.

1. First rectifying circuit

The first rectifying circuit may have an ac end and a dc end, and the ac end of the first rectifying circuit may be a single-phase ac end or a three-phase ac end, and is configured to receive a three-phase ac or a single-phase ac output from an ac power supply. The direct current end of the first rectifying circuit is connected with the third switching circuit and is used for outputting direct current obtained through rectification processing. The alternating current end of the first rectifying circuit is provided with at least two interfaces, and the specific number of the interfaces can be set according to the type of alternating current transmitted by the alternating current power supply. For example, when the ac power source uses a three-phase four-wire system to transmit three-phase ac power, four interfaces may be disposed in the ac end of the first rectifying circuit, and the four interfaces are respectively connected to three phase lines and one neutral line.

The first rectifying circuit may include at least two bridge arms, each bridge arm is connected in series with two switching devices, a middle node of each bridge arm is connected with one interface of the alternating current end, a first end of each bridge arm is connected with an interface receiving a high level in a first end of the third switching circuit, and a second end of each bridge arm is connected with an interface receiving a low level in a first end of the third switching circuit.

The number of bridge arms in the first rectifying circuit can be configured according to the type of alternating current transmitted on the alternating current power supply. The intermediate node of each bridge arm forms an alternating current end of the first rectifying circuit, and the first end and the second end of each bridge arm form a direct current end of the first rectifying circuit.

In practical application, the two switching devices connected in series in each bridge arm can be controllable switching devices or uncontrollable switching devices, so as to prevent the control devices of the controllable switching devices from being powered off and not working due to the fact that the electric energy is not stored in the battery pack and the bus capacitor, and the switching devices in the first rectifying circuit preferably adopt the uncontrollable switching devices.

For ease of understanding, an example of the first rectifying circuit structure is given below.

Referring to fig. 3, taking an example of outputting three-phase ac from an ac power supply, the first rectifying circuit may include three bridge arms, where the first bridge arm includes diodes D1 and D2 connected in series, the second bridge arm includes diodes D3 and D4 connected in series, and the third bridge arm includes diodes D5 and D6 connected in series. The intermediate nodes of diodes D1 and D2 may be connected to an interface receiving the alternating current of a, the intermediate nodes of diodes D3 and D4 may be connected to an interface receiving the alternating current of B, the intermediate nodes of diodes D5 and D6 may be connected to an interface receiving the alternating current of C, the first ends of diodes D1, D3 and D5 are connected to an interface receiving a high level in the first end of the third switching circuit, and the second ends of diodes D2, D4 and D6 are connected to an interface receiving a low level in the first end of the third switching circuit. The alternating current A, the alternating current B and the alternating current C are single-phase alternating currents, and the three single-phase alternating currents form three-phase alternating currents.

When the first rectifying circuit is connected with the third switching circuit, the first rectifying circuit is connected with the charge-discharge circuit, the voltage amplitude at two ends of the capacitor at the input end in the charge-discharge circuit may be lower, if the first rectifying circuit rectifies the electric energy output by the alternating current power supply and directly outputs the electric energy to the charge-discharge circuit, the electric energy may generate impact current to cause damage to a plurality of devices, therefore, the first rectifying circuit is further provided with a current limiting resistor, as shown in fig. 3, resistors R1 and R2 form the current limiting resistor, the current limiting resistor R1 is connected between the first ends of a plurality of bridge arms and the third switching circuit, and the current limiting resistor R2 is connected between the second ends of the plurality of bridge arms and the third switching circuit. The resistance values of the current limiting resistor R1 and the current limiting resistor R2 can be configured according to the current limit of the connected device.

In an example, to reduce the cost of the ups or reduce the size of the ups, only one current limiting resistor may be configured in the first rectifying circuit, and the current limiting resistor may be connected to a path between the switching device of the first rectifying circuit and the first capacitor C1.

Of course, the above description of the structure of the first rectifying circuit is merely exemplary, and in practical application, other structures may be adopted for the first rectifying circuit, for example, the first rectifying circuit may be a single-phase uncontrollable bridge circuit, so as to implement single-phase rectification.

2. Second rectifying circuit

The second rectifying circuit may have an input terminal and an output terminal, and the ac terminal of the second rectifying circuit may be connected to an external ac power supply through the first switching circuit, and the dc terminal of the second rectifying circuit may be connected to the bus capacitor.

The ac end of the second rectifying circuit may be a single-phase ac end or a three-phase ac end, and is configured to receive a three-phase ac or a single-phase ac output by the ac power supply. The alternating current end of the second rectifying circuit comprises at least two interfaces, and the specific number of the interfaces can be configured according to the type of alternating current transmitted by the alternating current power supply.

In practical application, the second rectifying circuit may be, but is not limited to, a fully-controlled rectifying circuit, a semi-controlled rectifying circuit and an uncontrollable rectifying circuit, where all the three types of rectifying circuits have one or more circuit topologies, and the circuit topologies can refer to the existing circuit structure with the rectifying function.

For ease of understanding, a schematic diagram of the structure of the second rectifying circuit is given below.

Taking the example of the ac power source outputting three-phase ac power, the second rectifying circuit may employ a conventional vienna circuit topology, as shown in fig. 4, and the first rectifying circuit may include energy storage inductors L1 to L3, diodes D7 to D12, and controllable switches Q1 to Q6. Wherein, diode D7 and D8 intermediate node can be connected with energy storage inductance L1, and diode D9 and D10 intermediate node can be connected with energy storage inductance L2, and diode D11 and D12 intermediate node can be connected with energy storage inductance L3, and diode D7, D9 and D11's first end all is connected with bus capacitor's first end, and diode D8, D10 and D12's second end all is connected with bus capacitor's second end. And after being connected in series, one end of the switching tube Q1 and Q2 is connected with the middle node of the diodes D7 and D8, and the other end of the switching tube Q1 and Q2 is connected with the middle node of the bus capacitor. And after being connected in series, one end of the switching tube Q3 and Q4 is connected with the middle node of the diodes D9 and D10, and the other end of the switching tube Q is connected with the middle node of the bus capacitor. And after being connected in series, one end of the switching tube Q5 and Q6 is connected with the middle node of the diodes D11 and D12, and the other end of the switching tube Q5 and Q6 is connected with the middle node of the bus capacitor. The energy storage inductor L1 is connected with a port which is intersected with the alternating current power supply output A through a first switch circuit, the energy storage inductor L2 is connected with a port which is intersected with the alternating current power supply output B through a first switch circuit, and the energy storage inductor L3 is connected with a port which is intersected with the alternating current power supply output C through a first switch circuit.

In an example, a parasitic diode is arranged in the switching device in the second rectifying circuit or a diode is connected in parallel across the switching device.

In an example, the above-mentioned switching device in the second rectifying circuit may also be an uncontrollable switching device.

Of course, the above description of the structure of the second rectifying circuit is merely an example, and in practical application, other structures may be adopted for the first rectifying circuit, which is not limited herein.

3. Bus capacitor

The bus capacitor may have a first end and a second end, the first end may be an end of the bus capacitor receiving a high level, and the second end may be an end of the bus capacitor receiving a low level.

In practical applications, the bus capacitor may include at least one capacitor. When the bus capacitor only comprises one capacitor, the first end of the capacitor is the first end of the bus capacitor, and the second end of the capacitor is the second end of the bus capacitor. When the bus capacitor includes a plurality of capacitors, the plurality of capacitors may be connected in series or in parallel.

In an example, if a plurality of capacitors in the bus capacitor are connected in parallel, first ends of the plurality of capacitors are connected to form a first end of the bus capacitor, and second ends of the plurality of capacitors are connected to form a second end of the bus capacitor.

In an example, if the plurality of capacitors in the bus capacitor are connected in series, a first end of a first capacitor in the plurality of capacitors in the series is a first end of the bus capacitor, and a second end of a last capacitor in the plurality of capacitors in the series is a second end of the bus capacitor. For example, referring to fig. 5, the bus capacitor includes a first capacitor C1 and a second capacitor C2 connected in series, where a first end of the first capacitor C1 is a first end of the bus capacitor, and a second end of the second capacitor C2 is a second end of the bus capacitor.

Of course, the above description of the structure of the bus capacitor is merely an example, and in practical application, other structures may be used for the bus capacitor, for example, when the bus capacitor includes a plurality of capacitors, some capacitors may be connected in series and then connected in parallel, or some capacitors may be connected in parallel and then connected in series.

4. Charging and discharging circuit

The charge/discharge circuit may have a first end and a second end, and the first end of the charge/discharge circuit may be connected to the battery pack through the second switch circuit, and may be connected to the first rectifying circuit through the third switch circuit. The second end of the charge-discharge circuit is connected with the bus capacitor.

The charge and discharge circuit may perform charge and discharge processes on the battery pack. When the external alternating current power supply is connected with the uninterrupted power supply and the uninterrupted power supply is in a normal power supply state, the second end of the charging and discharging circuit is used as an input end, the first end of the charging and discharging circuit is used as an output end, the charging and discharging circuit performs charging treatment, and the voltages at the two ends of the bus capacitor are converted into charging voltages of the battery pack and charge the battery pack. When the AC power supply fails, the first end of the charge-discharge circuit is used as an input end, the second end of the charge-discharge circuit is used as an output end, the charge-discharge circuit performs discharge treatment, converts the electric energy stored by the battery pack, outputs the electric energy to the bus capacitor, and supplies power to a load connected with the rear end of the bus capacitor after the voltage of the bus capacitor is stabilized. The charging and discharging circuit can also pre-charge the bus capacitor after boosting the electric energy stored in the battery pack or the electric energy output by the first rectifying circuit when the uninterrupted power supply is installed for the first time or the alternating current power supply fails.

In practical applications, the charge-discharge circuit may be, but is not limited to, a Boost circuit with a Boost function or a Buck-Boost circuit with a Boost function and a Buck function.

For ease of understanding, an example of the charge-discharge circuit structure is given below.

As shown in fig. 6, a schematic diagram of a charge-discharge circuit is shown in fig. 6, where the charge-discharge circuit includes a third capacitor C3, a switch Q7, a switch Q8, and a switch Q9, and energy storage inductors L4 and L5. The third capacitor C3 may be regarded as an input capacitor of the charge-discharge circuit, the first end of the switch Q7 is connected to the first end of the bus capacitor, the second end of the switch Q7 is connected to the first end of the switch Q8, the second end of the switch Q8 is connected to the first end of the switch Q9, the second end of the switch Q9 is connected to the second end of the bus capacitor, the first end of the energy storage inductor L4 is connected to the first end of the third capacitor C3, the second end of the energy storage inductor L4 is connected to the second end of the switch Q7, the first end of the energy storage inductor L5 is connected to the second end of the third capacitor C3, and the second end of the energy storage inductor L5 is connected to the second end of the switch Q8. The first end of the third capacitor C3 is connected with one end of the second switching circuit and one end of the third switching circuit outputting high level, and the second end of the third capacitor C3 is connected with one end of the second switching circuit and one end of the third switching circuit outputting low level.

In an example, if the switching devices in the charge-discharge circuit are MOSFETs, the switching devices are disposed inside parasitic diodes.

In another example, if the switching devices in the charge-discharge circuit are BJTs and IGBTs, no parasitic diode is present in the switching devices.

The precharge process of the bus capacitor by the charge/discharge circuit will be described in detail with reference to the charge/discharge circuit configuration shown in fig. 6.

Referring to fig. 6, after the third switching circuit is turned on, the first rectifying circuit rectifies the ac power output by the ac power supply into dc power, and transmits the dc power to the third capacitor C3 through the current limiting resistors R1 and R2, and if the voltage across the third capacitor C3 is zero, the electric energy output by the second rectifying circuit charges the third capacitor C3 first, so that the charge-discharge circuit enters a stable state. When the voltage at two ends of the third capacitor C3 is charged to the set voltage value, the switching device in the charge-discharge circuit is controlled to be conducted, and therefore boosting processing is conducted on the voltage at two ends of the third capacitor C3. Similarly, when the second switch circuit is closed and conducted, the charging and discharging circuit can conduct through the internal switch, and the bus capacitor is charged after boosting treatment is carried out on the electric energy stored by the battery pack.

When the voltage of the bus capacitor is charged to the first voltage, the switch Q7 and the switch Q9 can be controlled to be turned off after the bus capacitor is determined to be charged. When the bus capacitor has no charging requirement, the waste of electric energy is avoided, and the second switch circuit or the third switch circuit can be controlled to be turned off. The set voltage value can be configured according to parameters such as power supply requirements of loads and inductance of energy storage inductors.

Of course, the above description of the structure of the charge-discharge circuit is merely an example, and in practical application, the charge-discharge circuit may take other structures, as long as the circuit or the chip is capable of implementing the voltage boosting function, which is not limited herein.

5. First switch circuit

The first switch circuit is provided with a first end and a second end, the first end of the first switch circuit is used for being connected with an external alternating current power supply, the second end of the first switch circuit is connected with the second rectifying circuit, and the first switch circuit can control the connection of the alternating current power supply and the second rectifying circuit.

In practice, the first switching circuit may comprise at least one switching device, the number of which may be configured according to the type of ac power transmitted by the ac power source.

In an example, to reduce the cost of the ups, the switching devices in the first switching circuit are relays, and as shown in fig. 7, the first switching circuit may include three relays K1 to K3. One end of the relay K1 is connected with a phase line which transmits the alternating current in the alternating current power supply, and the other end of the relay K1 is connected with the energy storage inductor L1. One end of the relay K2 is connected with a phase line for transmitting B phase alternating current in the alternating current power supply, and the other end of the relay K2 is connected with the energy storage inductor L2. One end of the relay K3 is connected with a phase line for transmitting C-phase alternating current in the alternating current power supply, and the other end of the relay K3 is connected with the energy storage inductor L3. Wherein, when relays K1 to K3 are turned on, the first switching circuit is turned on. When the relays K1 to K3 are turned off, the first switching circuit is turned off.

Of course, the above description of the structure of the first switching circuit is merely an example, and in practical application, the switching device of the first switching circuit may be other switching devices besides the relay described above, which is not limited herein.

6. Second and third switch circuits

The second switching circuit has a first terminal and a second terminal, and the third switching circuit has a first terminal and a second terminal. The first end of the second switch circuit is connected with the battery pack, and the second end of the first switch circuit is connected with the charge-discharge circuit. The first end of the third switching circuit is connected with the direct current end of the first rectifying circuit, and the second end of the second switching circuit is connected with the charge-discharge circuit.

When the second switch circuit is conducted, the battery pack is connected with the charge-discharge circuit. And when the second switch circuit is turned off, the connection between the battery pack and the charge-discharge circuit is disconnected. When the third switch circuit is conducted, the first rectifying circuit is connected with the charging and discharging circuit. When the third switching circuit is turned off, the first rectifying circuit is disconnected from the charging and discharging circuit.

In practice, the second switching circuit and the third switching circuit may comprise at least one switching device.

In an example, referring to fig. 8, two relays K4 and K5 may be included in the first switching circuit, and two relays K6 and K7 may be included in the second switching circuit. The relay K4 is connected between the positive electrode of the battery pack and the first end of the third capacitor C3, the relay K5 is connected between the negative electrode of the battery pack and the second end of the third capacitor C3, the relay K6 is connected between the current limiting resistor R1 and the first end of the third capacitor C3, and the relay K7 is connected between the current limiting resistor R2 and the second end of the third capacitor C3.

Referring to fig. 8, when relays K4 and K5 are turned on, the battery pack is connected to the bus capacitor through a charge/discharge circuit, constituting a charge loop between the battery pack and the bus capacitor. When the relays K6 and K7 are conducted, the first rectifying circuit is connected with the bus capacitor through the charging and discharging circuit, and a charging loop between the first rectifying circuit and the bus capacitor is formed. Wherein the second switching circuit is in an on state when the relays K4 and K5 are on, and in an off state when one or both of the relays K4 and K5 are off. Similarly, when relays K6 and K7 are on, the third switching circuit is in an on state, and when one or both of relays K6 and K7 are off, the third switching circuit is in an off state.

In another example, to reduce the cost of the uninterruptible power supply, only one relay may be included in the second and third switching circuits. The relay in the second switching circuit is connected between the positive electrode of the battery pack and the first end of the third capacitor C3, or between the negative electrode of the battery pack and the second end of the third capacitor C3. The relay in the third switching circuit may be connected between the current limiting resistor R1 and the first terminal of the third capacitor C3, or between the current limiting resistor R2 and the second terminal of the third capacitor C3.

Of course, the above description of the structures of the second switch circuit and the third switch circuit is merely an example, and in practical application, the switch devices in the second switch circuit and the third switch circuit may be other switch devices besides relays, which is not limited herein.

The structure of a plurality of devices in the uninterruptible power supply and the precharge mode of the bus capacitor are introduced, and the voltage drop generated by alternating current power supply voltage fluctuation and internal load power supply can be compensated by adopting the devices in the precharge mode of the bus capacitor, so that the pressure difference between the bus capacitor and the alternating current power supply is reduced, the normal starting of the uninterruptible power supply is realized, and the safety of a switching device in the first switching circuit is protected. In addition, because the voltage difference between the alternating current power supply and the bus capacitor is reduced by adopting the bus capacitor for precharge, the second rectifying circuit connected between the alternating current power supply and the bus capacitor can adopt devices with smaller specification and lower cost, so that the cost of the uninterrupted power supply can be further reduced.

By adopting the mode, after the pre-charging of the bus capacitor is finished, the second rectifying circuit is controlled to operate, the electric energy output by the alternating current power supply is rectified, the power is supplied to a load connected with the rear end of the bus capacitor, and the uninterruptible power supply enters a stable working state. In practical application, the direct-current electric energy is transmitted on the bus capacitor, so that the bus capacitor can directly supply power to the direct-current load when the uninterruptible power supply is connected with the direct-current load. If the uninterruptible power supply is connected with an ac load, the uninterruptible power supply provided in the embodiment of the present application may further include an inverter circuit, where the inverter circuit is connected between the bus capacitor and the ac load, and converts dc electric energy on the bus capacitor into ac electric energy, and supplies power to the ac load.

In practical application, the inverter circuit may be an existing discrete circuit or chip with an inverter function, for example, the inverter circuit may include a plurality of bridge arms, and each bridge arm is connected in series with two switching devices. The number of bridge arms in the inverter circuit can be set according to the power supply requirement of the alternating current load. For example, if the ac load requires single-phase ac power for power supply, the inverter circuit may be an H-bridge inverter circuit configured by two bridge arms.

As can be seen from the above description, the circuits in the ups are all composed of switching devices, and the working process is realized by controlling the on and off of the switching devices. Accordingly, the uninterruptible power supply provided in the embodiments of the present application may further include a control device for turning on and off the switching device.

In a possible implementation manner, the uninterruptible power supply provided by the embodiment of the application may further include a first controller, where the first controller may be connected to the charging and discharging circuit and is configured to control the charging and discharging circuit to boost the voltage output by the battery pack or the first rectifying circuit and then charge the bus capacitor.

Specifically, a plurality of switching devices are arranged in the charging and discharging circuit, the first controller can be connected with the control end of the switching device in the circuit, and the charging and discharging circuit is controlled to boost the voltage output by the battery pack or the voltage output by the first rectifying circuit and then charge the bus capacitor by sending corresponding driving signals to the control end of the switching device.

In an example, the first controller may be further connected to the first switch circuit, the second switch circuit, and the third switch circuit, for controlling conduction of the first switch circuit, the second switch circuit, and the third switch circuit, so as to select a precharge mode of the bus capacitor, and control connection of the uninterruptible power supply to the ac power supply.

During practical application, the first switch circuit, the second switch circuit and the third switch circuit relay are provided with switches on the connecting wires of the first switch circuit, the second switch circuit and the third switch circuit relay and the power supply, the first controller can be connected with the control end of the switch, and the connection of the control relay and the power supply is realized by controlling the state of the switch, so that the aim of controlling the state of the relay is fulfilled.

In practical application, the first controller can also be connected with the second rectification circuit, and is used for controlling the second rectification circuit to carry out rectification processing after the first switch circuit is closed and supplying power to the load.

In another example, the uninterruptible power supply may further include a second controller connected to the first switch circuit, the second switch circuit, and the third switch circuit, respectively, for controlling conduction of the first switch circuit and the second switch circuit, and the third switch circuit.

Based on the same inventive concept, the embodiments of the present application also provide a power supply system that may include a load, a power source, and the aforementioned uninterruptible power supply.

The uninterruptible power supply is respectively connected with the load and the power supply and is used for converting the voltage output by the power supply into the power supply voltage of the load and supplying power to the load and is also used for converting the electric energy stored by the battery pack into the power supply voltage of the load and supplying power to the load when the power supply fails.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present application without departing from the scope of the application. Thus, if such modifications and variations of the present application fall within the scope of the claims and the equivalents thereof, the present application is intended to cover such modifications and variations.

Claims (9)

1. An uninterruptible power supply, comprising: the device comprises a first rectifying circuit, a charge-discharge circuit, a bus capacitor, a first switch circuit and a second rectifying circuit;

the first rectifying circuit is connected with the charging and discharging circuit and is used for being connected with an alternating current power supply, rectifying the voltage output by the alternating current power supply and outputting the rectified voltage to the charging and discharging circuit;

the charging and discharging circuit is connected with the bus capacitor and is used for charging the bus capacitor after boosting the voltage output by the first rectifying circuit until the voltage at two ends of the bus capacitor is charged to a first voltage which is larger than or equal to the peak value of the alternating current power supply;

The first switching circuit is connected with the second rectifying circuit and is used for being connected with an alternating current power supply, and when the voltage at two ends of the bus capacitor is charged to the first voltage, the alternating current power supply is controlled to be connected with the second rectifying circuit, so that the second rectifying circuit supplies power for equipment connected with the bus capacitor by utilizing the electric energy output by the alternating current power supply.

2. The uninterruptible power supply of claim 1, further comprising a battery pack;

the battery pack is connected with the charge-discharge circuit and is used for outputting the stored voltage to the charge-discharge circuit;

the charge-discharge circuit is also used for: and carrying out boosting treatment on the voltage output by the battery pack, and then charging the bus capacitor until the voltages at two ends of the bus capacitor are charged to the first voltage.

3. The uninterruptible power supply of claim 2, further comprising a second switching circuit connected between the battery pack and the charge-discharge circuit, and a third switching circuit connected between the first rectifying circuit and the charge-discharge circuit; the second switch circuit is used for controlling connection of the battery pack and the charging and discharging circuit, and the third switch circuit is used for controlling connection of the first rectifying circuit and the charging and discharging circuit.

4. The uninterruptible power supply of claim 3, further comprising a first controller connected to the charge-discharge circuit for controlling the charge-discharge circuit to boost the voltage output by the battery pack or the first rectifying circuit and then charge the bus capacitor.

5. The uninterruptible power supply of claim 4, wherein the first controller is further coupled to the first, second and third switching circuits for controlling conduction of the first, second and third switching circuits.

6. The uninterruptible power supply of claim 3, further comprising a second controller coupled to the first, second, and third switching circuits for controlling conduction of the first, second, and third switching circuits.

7. The uninterruptible power supply of claim 1, further comprising a voltage sensor connected to the bus capacitor for detecting a voltage across the bus capacitor.

8. The uninterruptible power supply of claim 1, further comprising an inverter circuit connected to the bus capacitor for converting a voltage across the bus capacitor to a supply voltage for a back-end connected load and supplying power to the load.

9. A power supply system, comprising: load, ac power supply and uninterruptible power supply according to any one of claims 1 to 8;

the uninterruptible power supply is respectively connected with the load and the alternating current power supply, and is used for converting the voltage output by the alternating current power supply into the power supply voltage of the load and supplying power to the load, and when the power supply fails, the battery pack in the uninterruptible power supply or the electric energy stored by the battery pack connected with the uninterruptible power supply is converted into the power supply voltage of the load and supplies power to the load.