Voltage sag resistant circuit and motor

Abstract

The utility model provides a voltage sag resistant circuit and a motor, the circuit comprises an energy storage module, the energy storage module comprises a first capacitor, a second capacitor, a first diode, a second diode and a third diode, the second end of the first capacitor is connected to the cathode of a first diode, and the anode of the first diode is grounded; the cathode of the second diode is connected to the energy exchange end of the circuit, the anode of the second diode is connected to the first end of the second capacitor, and the second end of the second capacitor is grounded; the anode of the third diode is connected between the first capacitor and the first diode, and the cathode of the third diode is connected between the second diode and the second capacitor. According to the anti-voltage sag circuit and the motor, the motor can be kept running continuously when voltage sag occurs. In addition, the circuit and the motor are small in size and low in cost, and the power factor of the system can be improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to electronic circuit, and especially relates to a kind of voltage sag resistance circuit and motor. BACKGROUND

[0002] With the continuous development of modern industry, the load of the back end of power system is more and more, and the load type is also various. Such a large number and variety of loads can cause voltage sag to the voltage of the power system. Voltage sag is one of the common voltage abnormal phenomena in power system, also known as flicker. Voltage sag usually refers to the voltage of the power system suddenly drops in a short time, and then returns to normal level. Voltage sag can be caused by many factors, such as the sudden start of high-power load, power system failure, motor start-up, etc. Voltage sag can cause equipment to run unstable, and even make the equipment stop working.

[0003] Under the application of motor load, in order to ensure that no significant economic loss is caused to the user when voltage sag occurs for a short time, the user generally requires the motor load to continue to run without being affected by voltage sag, and cannot appear the phenomenon of stuttering and stopping. In order to deal with this challenge, voltage sag resistance or flicker resistance solution becomes crucial.

[0004] Therefore, a solution is expected that can maintain the motor to continue running when voltage sag occurs in the power system. SUMMARY

[0005] According to an aspect of the embodiment of the utility model, a kind of circuit for voltage sag resistance is provided, it is characterized in that, including energy storage module, the energy storage module includes first capacitor, second capacitor, first diode, second diode and third diode, and wherein: the first end of the first capacitor is connected to the energy exchange end of the energy storage module, the second end of the first capacitor is connected to the cathode of the first diode, and the anode of the first diode is grounded;The cathode of the second diode is connected to the energy exchange end of the energy storage module, the anode of the second diode is connected to the first end of the second capacitor, and the second end of the second capacitor is grounded;The anode of the third diode is connected between the first capacitor and the first diode, and the cathode of the third diode is connected between the second diode and the second capacitor, and wherein, the energy storage module is configured to: in response to the energy storage module is in charging mode, the charging current input from the energy exchange end charges the first capacitor and the second capacitor by including first capacitor, third diode and second capacitor, in response to the energy storage module is in discharging mode, the first capacitor outputs first discharge current to the energy exchange end by including the first capacitor and the first diode, and the second capacitor outputs second discharge current to the energy exchange end by including the second capacitor and the second diode.

[0006] For example, the circuit according to the embodiment of the utility model, it is characterized in that, still include the boost conversion module being connected to the energy exchange end and alternating current power supply, the boost conversion module is configured to: alternating current power from alternating current power supply is converted into direct current power, the voltage of the direct current power is boosted, and direct current power with boosted voltage is output.

[0007] For example, the circuit according to the embodiment of the utility model, it is characterized in that, the boost conversion module is configured to: in response to the voltage of the alternating current power greater than first threshold voltage, direct current power with boosted voltage is output, in response to the voltage of the alternating current power not greater than the first threshold voltage, stop outputting direct current power with boosted voltage.

[0008] For example, the circuit according to the embodiment of the utility model, it is characterized in that, the energy storage module is configured to: in response to the voltage of the alternating current power greater than first threshold voltage, the energy storage module is in charging mode, in response to the voltage of the alternating current power not greater than the first threshold voltage, the energy storage module is in discharging mode.

[0009] For example, the circuit according to the embodiment of the present application, characterized in that, further comprising a chopping module connected to the boost conversion module and the energy storage module, the chopping module is configured to receive direct current power from the boost conversion module or the energy storage module, reduce the voltage of the received direct current power, and output direct current power with reduced voltage.

[0010] For example, the circuit according to the embodiment of the present application, characterized in that, further comprising a control module connected to the chopping module, the control module is configured to receive direct current power from the chopping module to control the turn-on and turn-off of the switching element of the motor through the driver.

[0011] For example, the circuit according to the embodiment of the present application, characterized in that, the control module is configured to receive direct current power from the energy storage module through the chopping module to control the turn-on of the switching element of the motor during the energy storage module is in the discharging mode.

[0012] For example, the circuit according to the embodiment of the present application, characterized in that, further comprising a voltage acquisition module connected to the alternating current power supply and the control module, the voltage acquisition module is configured to acquire the voltage of the alternating current power supply and output the voltage of the alternating current power supply to the control module.

[0013] For example, the circuit according to the embodiment of the present application, characterized in that, the control module is further configured to: in response to the voltage of the alternating current power supply being not greater than a second threshold voltage, turn off one or more of the group including the indicator component, the digital input component, the digital output component, the backlight component included in the human-computer interaction component, which are powered by the control module.

[0014] According to an aspect of the present application, a motor is provided, characterized in that, comprising the above-mentioned circuit for resisting voltage sag.

[0015] The circuit for resisting voltage sag and the motor according to the embodiment of the present application can reduce the voltage and capacity requirements of the energy storage capacitor, thereby reducing the volume and cost. Since the circuit for resisting voltage sag has a small volume, it can be integrated into the motor, making full use of the available space in the motor. In addition, the circuit for resisting voltage sag can be accurately configured according to the motor it is integrated into, without the need for users to separately calculate and configure parameters and separately configure external voltage sag resisting components, reducing the complexity of use for users. BRIEF DESCRIPTION OF DRAWINGS

[0016] The above and other aspects, features, and advantages of certain embodiments of the present application will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:

[0017] FIG. 1AA schematic diagram of a charging process of the energy storage module according to an embodiment of the present application is shown.

[0018] FIG. 1B A schematic diagram of a charging process of the energy storage module according to an embodiment of the present application is shown

[0019] FIG. 1C A schematic diagram of a discharging process of the energy storage module according to an embodiment of the present application is shown.

[0020] FIG. 2 An application scenario of the circuit for voltage sag resistance according to an embodiment of the present application is shown.

[0021] FIG. 3 A motor according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0022] Before undertaking the detailed description below, it can be advantageous to set forth definitions of certain words and phrases that have been used throughout the present application. The terms "include" and "comprise," as well as derivatives thereof, mean that something is contained, but does not mean the list is limited to only the items specifically listed. The phrase "at least one of," when used with a list of two or more items, means that at least one of the listed items is present in the item, but not only one and not necessarily all of the items specifically listed must be present in the item. For example, "at least one of A, B, and C" includes A, B, C, A and B, A and C, B and C, A and B and C, and so forth.

[0023] Definitions for other certain words and phrases are provided throughout this application. Those of ordinary skill in the art will understand that in many, if not most instances, such definitions apply to prior and future uses of such defined words and phrases.

[0024] Various embodiments of the principles of the application in the patent application document are described below in conjunction with the accompanying drawings. They are intended to be illustrative of the principles of the application and not limiting. Those of ordinary skill in the art will understand that the principles of the application can be implemented in any suitably arranged system or device. In some cases, the actions described by the application can be performed in a different order and still achieve the desired results. In addition, the processes depicted in the figures do not necessarily require the particular order or sequential order shown to achieve the desired results. In certain implementations, multi-tasking and parallel processing can be advantageous.

[0025] The text and drawings are provided as examples only to aid in the understanding of the present application. They should not be construed as limiting the scope of the claims of the present application in any way. Throughout the drawings, like reference numerals generally refer to like elements. Although certain embodiments and examples have been provided, it will be clear to those skilled in the art that changes in form and detail can be made to the embodiments and examples shown without departing from the spirit of the present application.

[0026] As described above, in the application of motor load, the user generally requires the motor load to continue to maintain operation without being affected by the voltage sag when the voltage sag occurs. However, the control module of the motor load can not be able to continue to control the motor due to the voltage sag, for example, the control module can not be able to control the power switch of the motor to be continuously turned on through the driver due to the voltage sag. Therefore, the motor can be stalled and stopped due to the power switch being turned off when the voltage sag occurs.

[0027] FIG. 1A A schematic diagram of an energy storage module of a circuit for voltage sag resistance according to an embodiment of the present application is shown.

[0028] As FIG. 1A shown, the circuit for voltage sag resistance can include an energy storage module 1000. The energy storage module 1000 can include a first capacitor 1100, a second capacitor 1400, a first diode 1200, a second diode 1300, and a third diode 1500. The first capacitor 1100 and the second capacitor 1400 can be configured to store and release electrical energy. The first diode 1200, the second diode 1300, and the third diode 1500 can be configured as unidirectional conduction circuits.

[0029] The energy storage module 1000 can be connected to an energy interaction end and a ground. The energy storage module 1000 can be connected to a direct current power supply and a direct current load (for example, a control module of a motor). According to an embodiment of the present disclosure, the energy storage module 1000 can receive direct current power from the direct current power supply through the energy interaction end and output direct current power to the direct current load through the energy interaction end.

[0030] The first capacitor 1100 of the energy storage module 1000 can be connected in series with the first diode 1200. For example, a first end of the first capacitor 1100 can be connected to the energy exchange end of the energy storage module 1000, a second end of the first capacitor 1100 can be connected to the cathode of the first diode 1200, and the anode of the first diode 1200 can be grounded.

[0031] The cathode of the second diode 1300 of the energy storage module 1000 can be connected to the energy exchange end of the energy storage module 1000, and the anode of the second diode 1300 can be connected to the first end of the second capacitor 1400, and the second end of the second capacitor 1400 can be grounded.

[0032] The anode of the third diode 1500 of the energy storage module 1000 can be connected between the first capacitor 1100 and the first diode 1200. For example, the anode of the third diode 1500 can be connected to the second end of the first capacitor 1100 and the cathode of the first diode 1200. The cathode of the third diode 1500 can be connected between the second diode 1300 and the second capacitor 1400. For example, the cathode of the third diode 1500 can be connected to the first end of the second capacitor 1400 and the anode of the first diode 1200.

[0033] FIG. 1B A schematic diagram of a discharging process of the energy storage module according to an embodiment of the present application is shown.

[0034] FIG. 1B The energy storage module 1000 shown in FIG. 1 can be in a charging mode. In response to the energy storage module 1000 being in the charging mode, the energy storage module 1000 can receive direct current power from a direct current power source through the energy interaction end. Specifically, the energy storage module 1000 can receive a charging current from the energy exchange end. The charging current can be a direct current. The charging current input from the energy exchange end can charge the first capacitor 1100 and the second capacitor 1400 through a charging path including the first capacitor 1100, the third diode 1500, and the second capacitor 1400. That is, the first capacitor 1100 and the second capacitor 1400 can store electrical energy in the charging mode. The capacitance values and voltage withstands of the first capacitor 1100 and the second capacitor 1200 can be set according to the configuration of the motor.

[0035] FIG. 1C A schematic diagram of a discharging process of the energy storage module according to an embodiment of the present application is shown.

[0036] FIG. 1CThe energy storage module 1000 shown in the figure can be in a discharging mode. In response to the energy storage module 1000 being in the discharging mode, the energy storage module 1000 can output direct current power to the direct current load through the energy interaction end. Specifically, in response to the energy storage module 1000 being in the discharging mode, the first capacitor 1100 can output a first discharging current to the energy exchange end through a first discharging path including the first capacitor 1100 and the first diode 1200, and the second capacitor 1400 can output a second discharging current to the energy exchange end through a second discharging path including the second capacitor 1400 and the second diode 1300. The first charging current and the second charging current can be direct current. That is, the first capacitor 1100 and the second capacitor 1400 can release the electrical energy stored therein in the discharging mode.

[0037] According to the energy storage module 1000 of the utility model, during charging, the first capacitor 1100 and the second capacitor 1200 can be connected in series. In this way, during the charging process, the voltage division of each capacitor can be reduced, thereby reducing the withstand voltage requirement of the capacitor. In addition, the capacitor connected in series can improve the ripple filtering and play a smoothing effect on the direct current, and can also improve the surge absorption capacity. According to the energy storage module 1000 of the utility model, during discharging, the first capacitor 1100 and the second capacitor 1200 can be connected in parallel. Since the capacitor connected in parallel increases the total capacitance, the capacity requirement of the capacitor is reduced. Since the withstand voltage and capacity requirements of the capacitor can be reduced at the same time, the size of the capacitor is reduced and the service life of the capacitor is increased, and the related cost is reduced. In addition, the energy storage module 1000 can play a similar function to the valley filling circuit, thereby improving the power factor of the power system and avoiding harmonic pollution to the power system.

[0038] FIG. 2 The application scenario of the circuit for resisting voltage sag according to the embodiment of the utility model is shown.

[0039] As FIG. 2 shown, the circuit for resisting voltage sag can include one or more of the group including a switching element 2100, a boost conversion module 2200, an energy storage module 1000, a chopping module 2300, a control module 2400, a voltage acquisition module 2500, and a driver 2600.

[0040] The boost conversion module 2200 can be connected to the energy exchange end of the energy storage module 1000 and an alternating current power source (e.g., a power input port of the motor 2700). The boost conversion module 2200 can receive alternating current power from the alternating current power source. For example, the boost conversion module 2200 can receive alternating current power as a line voltage or a phase voltage of a three-phase alternating current power source. The conversion function performed by the boost conversion module 2200 can include a rectification function and a boost function. Specifically, the boost conversion module 2200 can convert alternating current power from the alternating current power source into direct current power. The boost conversion module 2200 can boost the voltage of the direct current power and output the direct current power having the boosted voltage. For example, the boost conversion module 2200 can output the direct current power having the boosted voltage to the energy storage module 1000 and the chopper module 2300.

[0041] The boost conversion module 2200 can perform the conversion function in response to the voltage of the alternating current power being greater than a first threshold voltage. For example, the boost conversion module 2200 can output the direct current power having the boosted voltage in response to the voltage of the alternating current power being greater than the first threshold voltage. The first threshold voltage can be lower than a normal operating voltage of the alternating current power source, and can be 80 V (or greater or smaller), without being limited thereto.

[0042] The boost conversion module 2200 can stop performing the conversion function in response to the voltage of the alternating current power not being greater than the first threshold voltage. For example, the boost conversion module 2200 can stop outputting the direct current power having the boosted voltage in response to the voltage of the alternating current power not being greater than the first threshold voltage.

[0043] The energy storage module 1000 can be in a charging mode or a discharging mode depending on whether the boost conversion module 2200 performs the conversion function. According to an embodiment of the disclosure, the energy storage module 1000 can be in the charging mode in response to the voltage of the alternating current power being greater than the first threshold voltage. The energy storage module 1000 can be in the discharging mode in response to the voltage of the alternating current power not being greater than the first threshold voltage. In this way, the direct current power can be continuously output to the chopper module 2300 when a voltage sag occurs, thereby maintaining normal operation of the control module 2400.

[0044] The chopper module 2300 can be connected to the energy exchange end of the boost conversion module 2200 and the energy storage module 1000. The chopper module 2300 can be configured to receive direct current power from the boost conversion module 2200 or the energy storage module 1000. The chopper module 2300 can reduce the voltage of the received direct current power to a voltage (e.g., 24 V, 12 V, 5 V, 3.3 V, etc., without being limited thereto) adapted to the control module 2400, and output the direct current power having the reduced voltage to the control module 2400.

[0045] The control module 2400 can be connected to the chopper module 2300. The control module 2400 can include a micro control unit (MCU), a central processing unit (CPU), a digital signal processor (DSP), a single chip microcomputer, or other forms of processing units having data processing capabilities and / or program execution capabilities, such as a field programmable gate array (FPGA), etc. The control module 2400 can include a general purpose processor or a special purpose processor, and can perform desired functions. Although not shown, the control module 2400 can include a memory. The memory can include any combination of one or more computer program products, which can include various forms of computer readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may, for example, include random access memory (RAM), cache, etc. The non-volatile memory may, for example, include read only memory (ROM), hard disk, erasable programmable read only memory (EPROM), compact disc read only memory (CD-ROM), USB memory, flash memory, etc. One or more computer program modules can be stored on the computer readable storage media, and can be run to implement the anti-voltage sag function. Various application programs and various data used and / or generated by the application programs, etc. can also be stored in the computer readable storage media.

[0046] When the control module 2400 is powered, the control module 2400 can control the switch element 2100 to be turned on or off through the driver 2600, thereby controlling the motor 2700 to start or stop. When the control module 2400 is powered off, the control module 2400 can not be able to turn on the switch element 2100 through the driver 2600, so the switch element 2100 is turned off and the motor 2700 stops operating. The control module 2400 can be configured to receive direct current power from the chopper module 2300 to control the turn-on and turn-off of the switch element 2100 of the motor through the driver 2600. The switch element 2100 can include one or more of a group including MOSFET, IGBT, SiC, GaN devices.

[0047] As described above, the chopper module 2300 can receive direct current power from the boost conversion module 2200 when the alternating current power source outputs normal alternating current power. The chopper module 2300 can receive direct current power from the energy storage module 1000 when the alternating current power source outputs alternating current power having a voltage sag or during the discharge mode of the energy storage module 1000. In this way, the control function of the control module 2400 on the switch element 2100 can still be guaranteed when a voltage sag occurs, thereby controlling the switch element 2100 to be continuously turned on during the voltage sag to guarantee the continuous operation of the motor 2700.

[0048] Further, the control module 2400 can include one or more of a group comprising a communication component 2410, an indicator component 2420, a digital input component 2430, a digital output component 2440, a human-machine interaction component 2450. Although FIG. 2 Although the communication component 2410, the indicator component 2420, the digital input component 2430, the digital output component 2440, the human-machine interaction component 2450 are described as included in the control module 2400, one skilled in the art can understand that the communication component 2410, the indicator component 2420, the digital input component 2430, the digital output component 2440, the human-machine interaction component 2450 can be independent of the control module 2400. The communication component 2410, the indicator component 2420, the digital input component 2430, the digital output component 2440, the human-machine interaction component 2450 can be powered by the control module 2400.

[0049] The communication component 2410 can be configured to perform communication functions between the control module 2400 and a host at a higher layer. The indicator component 2420 can include indicator lights or other indication components to indicate to the user whether the relevant functions are performed normally. The digital input component 2430 can include dry contacts and the like, and is configured to receive digital inputs to perform various test functions, for example. The digital output component 2440 can be configured to output control signals to relays to perform control functions. The human-machine interaction component 2450 can display graphical interfaces and the like to the user to achieve device automation and the like. Backlight components 2451 such as LCDs can be included in the human-machine interaction component 2450 to display graphical interfaces and the like to the user at a higher brightness.

[0050] The control module 2400 can collect the voltage of the alternating power supply through the voltage collection module 2500. The voltage collection module 2500 can include one or more of a group comprising resistance voltage division, voltage transformer and operational amplifier sampling circuit. The voltage collection module 2500 can be connected to the alternating power supply and the control module 2400. The voltage collection module 2500 can output the voltage of the alternating power supply to the control module 2400.

[0051] The control module 2400 can turn off one or more non-essential components powered by the control module 2400 when the voltage sag occurs. The non-essential components can refer to components that have less or no impact on the control function of the control module 2400 to control the switching elements 2100 of the motor 2700. For example, in response to the voltage of the AC power source being no more than a second threshold voltage, the control module 2400 can turn off one or more of the group of components including the indicator component 2420, the digital input component 2430, the digital output component 2440, the backlight part 2451 included in the human-machine interaction component 2450. The second threshold voltage can be lower than the normal operating voltage of the AC power source, and can or can not be equal to the first threshold voltage. By turning off the unnecessary components, the power consumption of the control module 2400 can be further reduced, thereby maintaining the control function of the switching elements 2100. When the voltage sag is very serious (for example, the voltage sag duration is longer and the voltage drop value is larger), the communication component 2410 can also be turned off.

[0052] Although the voltage sag resistant circuit according to the present application is described in the implementation of the motor, it is understood by those skilled in the art that the voltage sag resistant circuit according to the present application can be integrated into or used in combination with any product that needs to resist voltage sag.

[0053] FIG. 3 A motor according to an embodiment of the present application is shown.

[0054] As shown in FIG. 3 The motor 3000 can include a voltage sag resistant circuit 3100. The voltage sag resistant circuit 3100 can be the voltage sag resistant circuit described with reference to FIGS. 1A-2 The description is not repeated here.

[0055] The voltage sag resistant circuit and the motor according to the embodiments of the present application can reduce the voltage and capacity requirements of the energy storage capacitor, thereby reducing the volume and cost. Since the voltage sag resistant circuit has a small volume, it can be integrated into the motor, making full use of the available space in the motor. In addition, the voltage sag resistant circuit can be accurately configured according to the motor it is integrated into, without the user having to calculate and configure the parameters of the external voltage sag resistant components separately, reducing the user's complexity.

[0056] Although the present application has been described with exemplary embodiments, various changes and modifications can be suggested to one skilled in the art. The present application is intended to cover such changes and modifications that fall within the scope of the appended claims.

[0057] No description in this utility model should be understood as suggesting that any particular element, step, or function is an essential element governing the scope of the claims. The scope of the patent subject matter is defined only by the claims.

Claims

1. A circuit (3100) against voltage sag, characterized in that, The energy storage module (1000) includes a first capacitor (1100), a second capacitor (1400), a first diode (1200), a second diode (1300), and a third diode (1500), and wherein: a first end of the first capacitor (1100) is connected to an energy exchange end of the energy storage module (1000), a second end of the first capacitor (1100) is connected to a cathode of the first diode (1200), an anode of the first diode (1200) is grounded; a cathode of the second diode (1300) is connected to the energy exchange end of the energy storage module (1000), an anode of the second diode (1300) is connected to a first end of the second capacitor (1400), a second end of the second capacitor (1400) is grounded; an anode of the third diode (1500) is connected between the first capacitor (1100) and the first diode (1200), a cathode of the third diode (1500) is connected between the second diode (1300) and the second capacitor (1400), and wherein the energy storage module (1000) is configured to: in response to the energy storage module (1000) being in a charging mode, a charging current input from the energy exchange end charges the first capacitor (1100) and the second capacitor (1400) through a charging path including the first capacitor (1100), the third diode (1500), and the second capacitor (1400), in response to the energy storage module (1000) being in a discharging mode, the first capacitor (1100) outputs a first discharging current radially to the energy exchange end through a first discharging path (3100) including the first capacitor (1100) and the first diode (1200), the second capacitor (1400) outputs a second discharging current radially to the energy exchange end through a second discharging path (3100) including the second capacitor (1400) and the second diode (1300).

2. The circuit (3100) of claim 1, characterized by Further comprising a boost conversion module (2200) connected to the energy exchange end and an alternating current power source, the boost conversion module (2200) is configured to: convert alternating current power from the alternating current power source into direct current power, boost a voltage of the direct current power, output the direct current power with the boosted voltage.

3. The circuit (3100) of claim 2, characterized by The boost conversion module (2200) is configured to: in response to a voltage of the alternating current power being greater than a first threshold voltage, output the direct current power with the boosted voltage, in response to the voltage of the alternating current power not being greater than the first threshold voltage, stop outputting the direct current power with the boosted voltage.

4. The circuit (3100) of claim 3, characterized by The energy storage module (1000) is configured to: in response to the voltage of the alternating current power being greater than the first threshold voltage, the energy storage module (1000) is in the charging mode, in response to the voltage of the alternating current power not being greater than the first threshold voltage, the energy storage module (1000) is in the discharging mode.

5. The circuit (3100) of claim 2, characterized by Also included is a chopper module (2300) connected to the boost conversion module (2200) and the energy storage module (1000), the chopper module (2300) is configured to: receive direct current power from the boost conversion module (2200) or the energy storage module (1000), reduce voltage of the received direct current power, output direct current power with reduced voltage.

6. The circuit (3100) of claim 5, characterized by Also included is a control module (2400) connected to the chopper module (2300), the control module (2400) is configured to receive direct current power from the chopper module (2300) to control turn-on and turn-off of switching elements (2100) of a motor (2700, 3000) by a driver.

7. The circuit (3100) of claim 6, characterized by The control module (2400) is configured to receive direct current power from the energy storage module (1000) by the chopper module (2300) to control turn-on of switching elements (2100) of a motor (2700, 3000) during the energy storage module (1000) is in the discharging mode.

8. The circuit (3100) of claim 6, characterized by Also included is a voltage acquisition module (2500) connected to an alternating current power supply and the control module (2400), the voltage acquisition module (2500) is configured to: acquire voltage of the alternating current power supply, output the voltage of the alternating current power supply to the control module (2400).

9. The circuit (3100) of claim 6, characterized by The control module (2400) is further configured to: in response to the voltage of the alternating current power supply is not greater than a second threshold voltage, turn off one or more of a group including an indicator component (2420), a digital input component (2430), a digital output component (2440), a backlight part (2451) included in a human-computer interaction component (2450) powered by the control module (2400).

10. An electric machine (2700, 3000) characterized by The anti-voltage sag circuit (3100) as claimed in any one of claims 1-9.

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