TW202121795A - Uninterruptible power supply system - Google Patents

Abstract

An uninterruptible power supply system is connected to a load, and supplies power to the load through a power unit or a battery unit. The uninterruptible power supply system includes an output end, a first switch, a second switch, a third switch, a controller, and a protection circuit. In a first period that the load is supplied power through the power unit, the controller controls turning on the first switch and the third switch and turning off the second switch. In a second period that the load is supplied power through the battery unit, the controller controls turning off the first switch and turning on the second switch and the third switch. In the first period, if at least one of the power unit and the output end is abnormal, or in the second period, if at least one of the battery unit and the output end is abnormal, the third switch is turned off through one of the protection circuit and the controller.

Description

Uninterruptible power supply system

The present invention relates to an uninterrupted power supply system, especially an uninterrupted power supply system with software and hardware protection.

Compared with commercial or industrial use, medical institutions require higher standards for power protection systems. Healthcare facilities must be equipped with a stable power supply to allow countless important healthcare devices to operate. For example, nuclear magnetic resonance (MRI), computer tomography (CT) scanners, X-rays, gas analyzers, ultrasound and imaging devices all need to be installed with uninterrupted power systems to ensure their operational efficiency. Since the operation of some medical facilities is related to the lives of patients, when an abnormality in the power supply causes the medical facility to fail to operate, it needs to be immediately known for follow-up processing, so how can we immediately and surely know that the power supply of the uninterruptible power system is abnormal Is very important.

The purpose of the present invention is to provide an uninterrupted power supply system to solve the problems of the prior art.

In order to achieve the aforementioned purpose, the uninterrupted power supply system proposed by the present invention is connected to a load, and supplies power to the load through a power supply unit or a battery unit. The uninterruptible power supply system includes an output terminal, a first switch, a second switch, a third switch, a controller, and a protection circuit. The output terminal is coupled to the load. The first switch has a first end and a second end coupled to the power supply unit. The second switch has a first terminal and a second terminal coupled to the battery unit. The third switch has a first terminal coupled to the first terminal of the first switch and the first terminal of the second switch, and a second terminal coupled to the output terminal. Among them, in the first period when the load is supplied through the power supply unit, the controller controls the first switch and the third switch to be turned on and the second switch is turned off, and in the second period when the load is supplied through the battery unit, the controller controls the first A switch is turned off and the second switch and the third switch are turned on, wherein in the first period, if at least one of the power supply unit and the output terminal is abnormal, or in the second period, if at least one of the battery unit and the output terminal is abnormal If it is abnormal, the third switch is turned off through at least one of the protection circuit and the controller.

With the proposed uninterrupted power supply system, the reliability and safety of power supply can be improved.

In order to have a better understanding of the technology, means and effects adopted by the present invention to achieve the intended purpose, please refer to the following detailed description and drawings of the present invention. I believe that the purpose, features and characteristics of the present invention can be obtained from this in depth and For specific understanding, however, the accompanying drawings are only provided for reference and illustration, and are not intended to limit the present invention.

The technical content and detailed description of the present invention are described below in conjunction with the drawings.

Please refer to FIG. 1, which is a system block diagram of the first embodiment of the uninterruptible power supply system of the present invention. The uninterrupted power supply system of the present invention provides uninterrupted power supply to the output terminal 30 through a power unit (PU) 10 or a battery unit 20. The power supply unit 10 may be an AC/DC converter for converting received AC power (for example, commercial power) into DC power. The output terminal 30 can be coupled to a load receiving DC power. Generally speaking, when the input power (for example, city power) received by the power supply unit 10 is normal, the uninterrupted power supply system is powered by the power supply unit 10. When the input power is abnormal, the uninterrupted power supply system switches to the battery unit 20 for power supply. The uninterruptible power supply system includes a first power supply path Ps1, a second power supply path Ps2, a first switch 11, a second switch 12, a third switch 13, a controller 40, and a protection circuit 70.

The first power supply path Ps1 is coupled between the power supply unit 10 and the output terminal 30, that is, the first power supply path Ps1 is a power supply path for transmitting the output power V _PU of the power supply unit 10. The second power supply path Ps2 is coupled between the battery unit 20 and the output terminal 30, that is, the second power supply path Ps2 is a power supply path for transmitting the output power V _BAT of the battery unit 20.

The first switch 11 is disposed on the first power supply path Ps1, and one end is coupled to the power supply unit 10. The second switch 12 is disposed on the second power supply path Ps2, and one end is coupled to the battery unit 20. The third switch 13 is disposed on the first power supply path Ps1 and the second power supply path Ps2, and one end is coupled to the first switch 11 and the second switch 12, and the other end is coupled to the output terminal 30. That is, the third switch 13 is arranged on the common path of the first power supply path Ps1 and the second power supply path Ps2. Among them, the first switch 11, the second switch 12, and the third switch 13 can be semiconductor power switches, such as MOSFET, BJT, IGBT, SCR... etc., and can also be mechanical switches, such as relay... etc. However, the present invention is not limited to the above-mentioned switch types.

In this embodiment, when power is supplied to the load through the power supply unit 10, the controller 40 controls the first switch 11 to be turned on through the first switch signal SW1 and controls the third switch 13 to be turned on through the third switch signal SW3 and through the second switch signal SW3. The switch signal SW2 controls the second switch 12 to be turned off. When power is supplied to the load through the battery unit 20, the controller 40 controls the first switch 11 to turn off through the first switch signal SW1, controls the second switch 12 to turn on through the second switch signal SW2, and controls the third switch through the third switch signal SW3. The switch 13 is turned on. During the period when the load is supplied through the power supply unit 10, if the first abnormal condition occurs in the power supply unit 10 or the third abnormal condition occurs at the output terminal 30, or when the load is supplied through the battery unit 20, if the battery unit 20 occurs When the second abnormal condition or the third abnormal condition occurs at the output terminal 30, the third switch 13 can be turned off through at least one of the protection circuit 70 and the controller 40.

The first abnormal condition may include an under voltage abnormality or an over voltage abnormality of the power supply unit 10; the second abnormal condition may include an under voltage abnormality of the battery unit 20; the third The abnormal condition may include an undervoltage abnormality or an over current abnormality at the output terminal 30.

In some embodiments, the controller 40 is, for example, a central processing unit (Central Processing Unit, CPU), or other programmable microprocessor (Microprocessor), digital signal processor (Digital Signal Processor, DSP), programmable Controllers, Application Specific Integrated Circuits (ASIC), Programmable Logic Device (PLD) or other similar devices. The protection circuit 70 is, for example, an analog circuit including a plurality of operational amplifiers, but it is not intended to limit the present invention.

The uninterrupted power supply system of the present invention is an uninterrupted power supply system protected by both software (ie, the controller 40) and hardware (ie, the protection circuit 70), so it has a double protection effect. In other words, if an abnormality occurs in the uninterruptible power supply system, even if one of the controller 40 and the protection circuit 70 is abnormal, there is still the other one who can determine the abnormality and take immediate action to avoid the back-end load. Unable to operate normally due to abnormal power supply but not judged, leading to accidents. The uninterruptible power supply system further includes an abnormality indicating unit 50 which is coupled to the controller 40 and the protection circuit 70. The abnormal indication unit 50 is used to indicate the occurrence of abnormal conditions when an abnormal condition occurs in the power supply unit 10, the battery unit 20 or the output terminal 30. The abnormality indicating unit 50 can be used as an indication through sound, light or other forms. In one embodiment, the abnormality indicating unit 50 can be a buzzer. When an abnormal situation occurs, the buzzer can be controlled to sound. Make the operator or user aware.

In an uninterrupted power supply system, the controller 40 and the abnormal indication unit 50 are powered by the output power V _{PU provided by the power supply unit 10 or the output power V BAT} provided by the battery unit 20. Specifically, when the power supply unit 10 supplies power, the output power V _{PU provided by the power supply unit 10 converts the output power V PU into a voltage V MCU} that can be used by the controller 40 through the first power converter 61, for example, but not limited to In addition, the output power V _{PU provided by the power supply unit 10 converts the output power V PU into a voltage V BAZ} that can be used by the abnormality indicating unit 50 through the second power converter 62, for example, but not limited to 16 volts. Similarly, when the battery unit 20 supplies power, the output power V _{BAT provided by the battery unit 20 converts the output power V BAT into a voltage V MCU} that can be used by the controller 40 through the first power converter 61, for example, but not limited to In addition, the output power V _{BAT provided by the battery unit 20 converts the output power V BAT into a voltage V BAZ} that can be used by the abnormality indicating unit 50 through the second power converter 62, for example, but not limited to 16 volts. In this way, the power supply through the power supply unit 10 or the battery unit 20 enables the controller 40 and the abnormality indicating unit 50 to maintain normal operation.

The types of abnormal protection provided by the present invention include the first abnormal condition of undervoltage abnormality or overvoltage abnormality of the power supply unit 10; the second abnormal condition of undervoltage abnormality of the battery unit 20; and the undervoltage abnormality or overcurrent abnormality of the output terminal 30. The third abnormal situation. Please refer to FIG. 3, which is a circuit block diagram of the protection circuit of the present invention. For the hardware protection method, the control signal corresponding to the above abnormal condition is directly generated through the hardware circuit, and the third switch 13 is controlled to turn off, so that the power supply unit 10 or the battery unit 20 and the output terminal 30 are disconnected. Isolate the damage to the system when an abnormal situation occurs. As shown in FIG. 3, the control signals are respectively the second output signal Spu_uvp and the first output signal Spu_ovp corresponding to the abnormal undervoltage and the abnormal overvoltage of the power supply unit 10, and those corresponding to the abnormal undervoltage of the battery unit 20. The third output signal Sbat_uvp and the fourth output signal Sout_uvp and the fifth output signal Sout_ocp corresponding to the abnormal undervoltage and overcurrent occurrence of the output terminal 30 have the corresponding relationship as listed in the following table. Source of anomaly Type of abnormality Corresponding control signal Power supply unit Overvoltage abnormality occurred The first output signal Spu_ovp Power supply unit Undervoltage abnormal The second output signal Spu_uvp Battery unit Undervoltage abnormal The third output signal Sbat_uvp Output Undervoltage abnormal The fourth output signal Sout_uvp Output Overcurrent abnormality occurred The fifth output signal Sout_ocp

As shown in FIG. 3, the control signal corresponding to the above-mentioned abnormal type is generated through the protection circuit 70. Specifically, the detection of the abnormal undervoltage of the power supply unit 10 is through a voltage divider circuit (as shown in FIG. 1) provided on the side of the power supply unit 10, and the first voltage signal obtained by _{dividing the output power supply V PU} pu_vs1, using one of the comparison units (for example, operational amplifier) of the protection circuit 70 to compare with the second reference voltage pu_REF. If the divided first voltage signal pu_vs1 is less than the second reference voltage pu_REF (or the voltage obtained by dividing the second reference voltage pu_REF), it is detected that the power supply unit 10 has an abnormal undervoltage, and the output of the comparison unit is high at this time. And activate the corresponding latch circuit in the protection circuit 70, so that the protection circuit 70 outputs the second output signal Spu_uvp with a high level.

Refer to FIG. 4 again, which is a block diagram of the circuit for controlling the third switch in a hardware and software manner according to the present invention. The high-level second output signal Spu_uvp controls the first control switch Qsw31 to turn on, so that the second control switch Qsw32 is turned off accordingly. Therefore, the third switch 13 is controlled to turn off, so that when the power supply unit 10 has an under-voltage abnormality, through The third switch 13 is turned off to prevent the abnormally under-voltage power supply unit 10 from supplying power to the system. In addition, please refer to FIG. 5, which is a block diagram of the circuit for controlling the abnormal indication unit in a hardware manner according to the present invention. When an undervoltage abnormality occurs in the power supply unit 10, the high-level second output signal Spu_uvp simultaneously controls the third control switch Q _{BAZ to be} turned on, so that the abnormality indication unit 50 (take a buzzer as an example) emits a sound to inform the operator of the power supply The unit 10 has an undervoltage abnormality.

Similarly, the detection of the abnormal overvoltage of the power supply unit 10 is also performed by the voltage divider circuit (as shown in FIG. 1) provided on the power supply unit 10 side, and the obtained first voltage signal pu_vs1 is used by the protection circuit 70 One of the comparison units is compared with a first reference voltage (for example, 10 volts). If the divided first voltage signal pu_vs1 is greater than the first reference voltage of 10 volts (or the voltage obtained by dividing the first reference voltage of 10 volts), it is detected that the power supply unit 10 has an abnormal overvoltage, and the comparison unit The high-level signal is output, and the corresponding latch circuit in the protection circuit 70 is activated, so that the protection circuit 70 outputs the high-level first output signal Spu_ovp to the first control switch Qsw31. The subsequent operations can refer to the previous embodiment, and will not be repeated here.

Similarly, the detection of the under-voltage abnormality of the battery cell 20 is also through the voltage divider circuit (as shown in FIG. 1) provided on the battery cell 20 side, and the obtained second voltage signal bat_vs1 is used by the protection circuit 70 One of the comparison units is compared with a reference voltage (for example, 10 volts). If the divided second voltage signal bat_vs1 is less than the reference voltage of 10 volts (or the voltage obtained by dividing the reference voltage of 10 volts), it is detected that the battery cell 20 has an under-voltage abnormality. Therefore, hardware protection needs to be activated. At this time, the comparison unit outputs a high-level signal, and activates the corresponding latch circuit in the protection circuit 70, so that the protection circuit 70 outputs a high-level third output signal Sbat_uvp to the first control switch Qsw31. The subsequent operations can refer to the previous embodiment, and will not be repeated here.

Similarly, the detection of the under-voltage abnormality at the output terminal 30 is also through the voltage divider circuit (as shown in FIG. 1) provided on the output terminal 30 side, and the obtained third voltage signal out_vs1 is used by the protection circuit 70 One of the comparison units is compared with the third reference voltage out_REF. If the divided third voltage signal out_vs1 is less than the third reference voltage out_REF (or the voltage obtained by dividing the third reference voltage out_REF), it is detected that the output terminal 30 has an abnormal under-voltage, and the output of the comparison unit is high at this time And activate the corresponding latch circuit in the protection circuit 70, so that the protection circuit 70 outputs a high-level fourth output signal Sout_uvp to the first control switch Qsw31. The subsequent operations can refer to the previous embodiment, and will not be repeated here.

As for the detection of the abnormal over-current of the output terminal 30, the current detection circuit (as shown in FIG. 7) is provided on the output terminal 30, which is the detection of the output terminal by means of hardware and software in the present invention. The circuit block diagram for measuring the output current), the voltage Vh converted by the output current Iout flowing through the first resistor Rh is provided to the protection circuit 70 shown in FIG. 3, and the voltage Vh signal is amplified by a first-stage operational amplifier to obtain the output The first current signal Isen is compared with the reference current i_REF by one of the comparison units of the protection circuit 70. If the first current signal Isen is greater than the reference current i_REF, it is detected that the output terminal 30 has an overcurrent abnormality. Therefore, the hardware protection needs to be activated. At this time, the comparison unit outputs a high level signal and activates the corresponding one in the protection circuit 70. The circuit is latched, so that the protection circuit 70 outputs a high-level fifth output signal Sout_ocp to the first control switch Qsw31. The subsequent operations can refer to the previous embodiment, and will not be repeated here.

In summary, the description of the abnormal conditions of the power supply unit 10, the battery unit 20, and the output terminal 30 is mainly based on the control signal corresponding to the abnormal type generated by the protection circuit 70 (ie, the hardware architecture), and the third switch 13 and the abnormal indication unit 50 performs control so that when any abnormal situation occurs, the hardware protection is activated, the third switch 13 is turned off, and the abnormality indicating unit 50 is activated, so that the operator can immediately find the system abnormality and can quickly deal with it.

Hereinafter, the description will be directed to the activation of software protection (that is, control through the controller 40) when an abnormal situation occurs. Please refer to FIG. 2, which is a system block diagram of the second embodiment of the uninterruptible power supply system of the present invention. As shown in Figure 2, since the system architecture is basically the same as Figure 1, it will not be repeated.

As shown in FIG. 2, the controller 40 receives at least one detection signal, and directly outputs the third switch signal SW3 to control turning off the third switch 13, and directly outputs the sixth switch signal SW6 to control the third control switch Q _{BAZ to} turn on. The abnormality instruction unit 50 is activated. The detection signal includes a first voltage signal pu_vs2 corresponding to the power supply unit 10, a second voltage signal bat_vs2 corresponding to the battery unit 20, a third voltage signal out_vs2 corresponding to the output terminal 30, and a current signal corresponding to the output terminal 30 out_is, the corresponding relationship listed in the following table. Source of anomaly Type of abnormality Corresponding control signal Power supply unit Undervoltage abnormal The first voltage signal pu_vs2 Power supply unit Overvoltage abnormality occurred The first voltage signal pu_vs2 Battery unit Undervoltage abnormal The second voltage signal bat_vs2 Output Undervoltage abnormal The third voltage signal out_vs2 Output Overcurrent abnormality occurred Current signal out_is

Specifically, the detection of the abnormal under-voltage occurrence of the power supply unit 10 is through a voltage divider circuit (as shown in FIG. 2) provided on the side of the power supply unit 10 to divide the output power V _PU into a first voltage signal. pu_vs2 is provided to the controller 40, and the controller 40 compares the first voltage signal pu_vs2 with the internally designed voltage value (for example, less than a threshold voltage), determines that the power supply unit 10 is under-voltage abnormal, and outputs the third switch signal SW3 , The second control switch Qsw32 is controlled to be turned off (as shown in Figure 4). Therefore, the third switch 13 is controlled to be turned off, so that when an abnormal undervoltage occurs in the power supply unit 10, the third switch 13 is turned off to avoid abnormal undervoltage. The voltage power supply unit 10 supplies power to the system. In addition, please refer to FIG. 6, which is a block diagram of the circuit for controlling the abnormality indication unit by software in the present invention. When an under-voltage abnormality occurs in the power supply unit 10, the high-level sixth switch signal SW6 simultaneously controls the third control switch Q _{BAZ to be} turned on, so that the abnormality indication unit 50 (take a buzzer as an example) emits a sound to inform the operator of the power supply The unit 10 has an undervoltage abnormality.

Similarly, the detection of the abnormal overvoltage of the power supply unit 10 is through the voltage divider circuit (as shown in FIG. 2) provided on the power supply unit 10, and the first voltage signal obtained by _{dividing the output power supply V PU} pu_vs2 is provided to the controller 40, and the controller 40 compares the first voltage signal pu_vs2 with the internally designed voltage value (for example, greater than a threshold voltage), determines that the power supply unit 10 has an abnormal overvoltage, and outputs a third switch signal SW3 , The second control switch Qsw32 is controlled to be turned off, and then the third switch 13 is controlled to be turned off. The subsequent operations can refer to the previous embodiment, and will not be repeated here.

Similarly, the detection of the under-voltage abnormality of the battery unit 20 is through a voltage divider circuit (as shown in FIG. 2) provided on the side of the battery unit 20 to divide the output power V _BAT into a second voltage signal. bat_vs2 is provided to the controller 40, and the controller 40 compares the second voltage signal bat_vs2 with the internally designed voltage value (for example, less than a threshold voltage), determines that the power supply unit 10 has an abnormal undervoltage, and outputs a third switch signal SW3 , The second control switch Qsw32 is controlled to be turned off, and then the third switch 13 is controlled to be turned off. The subsequent operations can refer to the previous embodiment, and will not be repeated here.

Similarly, the detection of the under-voltage abnormality at the output terminal 30 is achieved through a voltage divider circuit (as shown in FIG. 2) provided on the output terminal 30, and the obtained third voltage signal out_vs2 is provided to the controller 40 , The controller 40 compares the third voltage signal out_vs2 with the internally designed voltage value (for example, less than a threshold voltage), determines that the output terminal 30 has an abnormal undervoltage, outputs the third switch signal SW3, and controls the second control switch Qsw32 is turned off to control the third switch 13 to turn off. The subsequent operations can refer to the previous embodiment, and will not be repeated here.

As for the detection of the abnormal overcurrent at the output terminal 30, the current detection circuit (as shown in FIG. 7) is provided on the output terminal 30, and the output current Iout flows through the voltage Vs converted by the second resistor Rs. Provided to the conversion circuit shown in FIG. 8 (which is a circuit diagram for converting the output current detected by the output terminal into a detection signal) to convert the voltage Vs into the current signal out_is. The converted current signal out_is is provided to the controller 40, and the controller 40 compares this current with the internally designed current value (for example, greater than a critical current), determines that the output terminal 30 has an abnormal overcurrent, and outputs a third switch signal SW3, controls the second control switch Qsw32 to turn off and then controls the third switch 13 to turn off. The subsequent operations can refer to the previous embodiment, and will not be repeated here.

In summary, the present invention has the following features and advantages:

1. It can have both software (such as the controller 40) and hardware (such as the protection circuit 70) protection mechanism to improve the reliability and safety of the uninterrupted power supply system.

2. The abnormality indication unit (such as a buzzer) is used as a notification to the operator when an abnormal situation occurs, so that the operator can immediately find that the system is abnormal and can quickly deal with it.

The above are only detailed descriptions and drawings of the preferred embodiments of the present invention. However, the features of the present invention are not limited to these, and are not intended to limit the present invention. The full scope of the present invention should be covered by the following patent application scope As the standard, all embodiments that conform to the spirit of the patent application of the present invention and similar changes should be included in the scope of the present invention. Anyone familiar with the art in the field of the present invention can easily think of changes or Modifications can be covered in the following patent scope of this case.

10: Power supply unit

20: battery unit

30: output

11: The first switch

12: The second switch

13: The third switch

40: Controller

50: Abnormal indication unit

61: The first power converter

62: The second power converter

70: Protection circuit

Ps1: The first power supply path

Ps2: second power supply path

V _PU : output power

V _BAT : output power

V _MCU : Voltage

V _BAZ : Voltage

SW1: The first switch signal

SW2: The second switch signal

SW3: third switch signal

SW6: The sixth switch signal

Qsw31: The first control switch

Qsw32: The second control switch

Q _BAZ : The third control switch

Rh: first resistance

Rs: second resistance

pu_vs1: the first voltage signal

bat_vs1: second voltage signal

out_vs1: third voltage signal

Iout: output current

out_is: current signal

out_REF: third reference voltage

pu_REF: second reference voltage

Isen: first current signal

i_REF: Reference current

Vh: voltage

Vs: voltage

Spu_uvp: second output signal

Spu_ovp: the first output signal

Sbat_uvp: third output signal

Sout_uvp: the fourth output signal

Sout_ocp: fifth output signal

pu_vs2: the first voltage signal

bat_vs2: second voltage signal

out_vs2: third voltage signal

Figure 1 is a system block diagram of the first embodiment of the uninterruptible power supply system of the present invention.

Figure 2 is a system block diagram of the second embodiment of the uninterrupted power supply system of the present invention.

Figure 3: A circuit block diagram of the protection circuit of the present invention.

Fig. 4 is a block diagram of the circuit for controlling the third switch by means of hardware and software according to the present invention.

Fig. 5 is a block diagram of a circuit for controlling the abnormality indication unit in a hardware manner according to the present invention.

Fig. 6 is a block diagram of the circuit for controlling the abnormal indication unit in software mode according to the present invention.

Fig. 7 is a block diagram of the circuit for detecting the output current on the output terminal by means of hardware and software according to the present invention.

FIG. 8 is a circuit diagram of the present invention, which detects the output current of the output terminal and converts it into a detection signal by means of software.

10: Power supply unit

20: battery unit

30: output

11: The first switch

12: The second switch

13: The third switch

40: Controller

50: Abnormal indication unit

61: The first power converter

62: The second power converter

70: Protection circuit

Ps1: The first power supply path

Ps2: second power supply path

V _PU : output power

V _BAT : output power

V _MCU : Voltage

V _BAZ : Voltage

SW1: The first switch signal

SW2: The second switch signal

SW3: third switch signal

SW6: The sixth switch signal

pu_vs1: the first voltage signal

bat_vs1: second voltage signal

out_vs1: third voltage signal

Spu_ovp: the first output signal

Spu_uvp: second output signal

Sbat_uvp: third output signal

Sout_uvp: the fourth output signal

Sout_ocp: fifth output signal

Claims (10)

An uninterrupted power supply system that connects to a load and supplies power to the load through a power supply unit or a battery unit. The uninterrupted power supply system includes: An output terminal, coupled to the load; A first switch having a first end and a second end coupled to the power supply unit; A second switch having a first terminal and a second terminal coupled to the battery unit; A third switch having a first end coupled to the first end of the first switch and the first end of the second switch, and a second end coupled to the output end; A controller; and A protection circuit; Wherein, when the load is supplied through the power supply unit for a first period, the controller controls the first switch and the third switch to be turned on and the second switch is turned off, when the load is supplied through the battery unit In a second period, the controller controls the first switch to be turned off and the second switch and the third switch to be turned on. In the first period, if at least one of the power supply unit and the output terminal is abnormal, Or during the second period, if at least one of the battery unit and the output terminal is abnormal, the third switch is turned off through at least one of the protection circuit and the controller. For example, the uninterrupted power supply system described in item 1 of the scope of patent application includes: An abnormal indication unit, coupled to the protection circuit and the controller; Wherein, when an abnormality occurs in the power supply unit, the battery unit, or the output terminal, the abnormality indication unit acts. Such as the uninterrupted power supply system described in item 1 of the scope of patent application, in which: The abnormality of the power supply unit includes an undervoltage abnormality or an overvoltage abnormality; The abnormality of the battery unit includes an undervoltage abnormality; and The abnormality of the output terminal includes an under-voltage abnormality or an over-current abnormality. In the uninterrupted power supply system described in claim 1, wherein the controller receives a plurality of detection signals, and generates a switch signal according to the detection signals to control the turn-on or turn-off of the third switch. The uninterrupted power supply system described in item 4 of the scope of patent application, wherein the detection signals include a first voltage signal corresponding to the power supply unit, a second voltage signal corresponding to the battery unit, and the output A third voltage signal and a first current signal corresponding to the terminal. For the uninterrupted power supply system described in item 1 of the scope of patent application, the protection circuit includes: A first comparator that compares a first voltage signal corresponding to the power supply unit with a first reference voltage to generate a first output signal, thereby determining whether the power supply unit has overvoltage; A second comparator, which compares the first voltage signal with a second reference voltage to generate a second output signal, thereby determining whether the power supply unit has undervoltage; A third comparator, which compares a second voltage signal corresponding to the battery cell with the first reference voltage to generate a third output signal, thereby determining whether the battery cell has undervoltage; A fourth comparator, which compares a third voltage signal corresponding to the output terminal with a third reference voltage to generate a fourth output signal, thereby determining whether an undervoltage occurs at the output terminal; and A fifth comparator compares a first current signal corresponding to the output terminal with a reference current to generate a fifth output signal, thereby determining whether an overcurrent occurs at the output terminal. For example, the uninterrupted power supply system described in item 6 of the scope of patent application includes: A fourth switch, including: A control terminal receives the first output signal, the second output signal, the third output signal, the fourth output signal, and the fifth output signal; and A first end; and A fifth switch, including: A control terminal electrically connected to the first terminal of the fourth switch; and A first terminal is electrically connected to the third switch. The uninterrupted power supply system described in item 7 of the scope of patent application, wherein the controller receives a plurality of detection signals, and generates a switch signal according to the detection signals, wherein the control terminal of the fifth switch also receives The switch signal. Such as the uninterrupted power supply system described in item 8 of the scope of patent application, wherein when the switch signal has a high logic level, or the first output signal, the second output signal, the third output signal, the fourth At least one of the output signal and the fifth output signal has a high logic level, and the fifth switch is turned off to turn on the third switch. The uninterrupted power supply system described in item 8 of the scope of patent application further includes a voltage division generating circuit electrically connected to the output terminal. The voltage division generating circuit generates a first voltage and a second voltage according to the output current of the output terminal. The first voltage corresponds to the first current signal, and the second voltage corresponds to a second current signal, which is provided to the controller to determine whether an overcurrent occurs at the output terminal.

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