Power-on / off circuit, control method of the circuit, and brushless direct current motor

Abstract

The embodiment of the application discloses a power-on and power-off circuit, a control method of the circuit and a brushless direct current motor. The power-on and power-off circuit comprises an alternating current input unit, a rectifier circuit, a bus voltage filter capacitor, a charging circuit, a voltage dividing circuit, a control circuit and a to-be-detected unit. The control circuit comprises a plurality of control switches, and the plurality of control switches are used for controlling the voltage of the to-be-detected unit. Through the application, the problem that the power-on and power-off circuit in the related art needs to discharge the bus voltage filter capacitor after detecting the target each time, needs to charge the bus voltage filter capacitor before detecting the next target, and thus the time consumption is relatively long, resulting in low production efficiency is solved, and the technical effect of reducing the production time consumption and improving the production efficiency is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of drive control system, and particularly relates to a power-on and power-off circuit, a control method of the circuit and a brushless direct current motor. BACKGROUND

[0002] In the prior art, as shown in Fig. 1, a power-on and power-off circuit includes an alternating current input unit 11, a rectifier circuit 12, a charging circuit 13 composed of an operating switch and a resistor, a bus voltage filter capacitor 14, a discharging circuit 15 composed of a resistor and a control switch, and a to-be-detected unit 16, wherein the to-be-detected unit 16 includes a predetermined capacitor 17 and a to-be-detected subunit 18 composed of an inverter circuit and a motor. The to-be-detected unit is a detected target, and the bus voltage filter capacitor voltage Vdc is connected to the detected target. After detecting the detected target each time, the bus voltage filter capacitor 14 is discharged first, and the bus voltage filter capacitor 14 needs to be charged when detecting the next target. The charging and discharging time is about 4 seconds, and the time interval of each motor and controller in the production line is 8 seconds, which reduces the labor production efficiency.

[0003] In the related art, after detecting the detected target each time, the bus voltage filter capacitor needs to be discharged first, and the bus voltage filter capacitor needs to be charged when detecting the next detected target, which consumes a long time and leads to low production efficiency. However, no effective solution has been proposed. SUMMARY

[0004] Embodiments of the present application provide a power-on and power-off circuit, a control method of the circuit and a brushless direct current motor, which at least solve the technical problem that, in the related art, after detecting the detected target each time, the bus voltage filter capacitor needs to be discharged first, and the bus voltage filter capacitor needs to be charged when detecting the next detected target, which consumes a long time and leads to low production efficiency.

[0005] According to one aspect of the present invention, a power-on / power-off circuit is provided, comprising: an AC input unit; a unit to be tested; a rectifier circuit, wherein a first terminal of the rectifier circuit is connected to a first terminal of the AC input unit, and a second terminal of the rectifier circuit is connected to a second terminal of the AC input unit; a charging circuit, wherein a first terminal of the charging circuit is connected to a third terminal of the rectifier circuit, and a second terminal of the charging circuit is connected to a first terminal of the unit to be tested; a voltage divider circuit, wherein a first terminal of the voltage divider circuit is connected to a first terminal of the unit to be tested, and a second terminal of the voltage divider circuit is connected to a fourth terminal of the rectifier circuit; a control circuit, wherein a first terminal of the control circuit is connected to a first terminal of the voltage divider circuit, and a second terminal of the control circuit is connected to a second terminal of the unit to be tested; and a bus voltage filter capacitor, wherein a first terminal of the bus voltage filter capacitor is connected to a line between the charging circuit and the voltage divider circuit, and a second terminal of the bus voltage filter capacitor is connected to a line between the rectifier circuit and the voltage divider circuit; wherein the control circuit includes a plurality of control switches, the plurality of control switches being used to control the voltage of the unit to be tested.

[0006] Optionally, the voltage divider circuit includes multiple capacitors, wherein the multiple capacitors are connected in series to form the voltage divider circuit.

[0007] Optionally, the voltage divider circuit includes multiple resistors, wherein the multiple resistors are connected in series to form the voltage divider circuit.

[0008] Optionally, the plurality of resistors includes at least a first resistor, a second resistor, and a third resistor, wherein a first end of the first resistor is connected to a second end of the charging circuit, a second end of the first resistor is connected to a first end of the second resistor, a second end of the second resistor is connected to a first end of the third resistor, and a second end of the third resistor is connected to a fourth end of the rectifier circuit.

[0009] Optionally, the plurality of control switches include at least a first control switch, a second control switch, and a third control switch, wherein a first terminal of the first control switch is connected to a second terminal of the third resistor, a second terminal of the first control switch is connected to a second terminal of the unit to be tested, a first terminal of the second control switch is connected to the line between the first control switch and the unit to be tested, a second terminal of the second control switch is connected to the line between the second resistor and the third resistor, a first terminal of the third control switch is connected to the line between the first control switch and the unit to be tested, and a second terminal of the third control switch is connected to the line between the first resistor and the second resistor.

[0010] Optionally, when the first control switch and the second control switch are disconnected and the third control switch is closed, the voltage of the unit to be detected is a first voltage; after waiting for a first preset time, and when the second control switch is closed and the third control switch is disconnected, the voltage of the unit to be detected is a second voltage; after waiting for a second preset time, and when the first control switch is closed and the second control switch is disconnected, the voltage of the unit to be detected is a third voltage.

[0011] Optionally, the charging circuit includes at least a fourth operating switch and a fourth resistor, wherein the fourth operating switch and the fourth resistor are connected in parallel to form the charging circuit.

[0012] According to another aspect of the present invention, a circuit control method is also provided, applied to the power-on / power-off circuit described in any one of the above embodiments, wherein the plurality of control switches include at least a first control switch, a second control switch, and a third control switch, the method comprising: controlling the first control switch and the second control switch to be disconnected, closing the third control switch, detecting the voltage of a unit to be detected, and recording the detected voltage of the unit to be detected as a first voltage; waiting for a first preset time, controlling the second control switch to be closed and the third control switch to be disconnected, detecting the voltage of the unit to be detected, and recording the detected voltage of the unit to be detected as a second voltage; waiting for a second preset time, controlling the first control switch to be closed and the second control switch to be disconnected, detecting the voltage of the unit to be detected, and recording the detected voltage of the unit to be detected as a third voltage.

[0013] According to another aspect of the present invention, a brushless DC motor is also provided, the brushless DC motor including the power-on and power-off circuit described in any one of the above embodiments.

[0014] In this embodiment of the invention, the power-on / power-off circuit includes an AC input unit; a unit to be tested; a rectifier circuit, with a first terminal connected to the first terminal of the AC input unit and a second terminal connected to the second terminal of the AC input unit; a charging circuit, with a first terminal connected to the third terminal of the rectifier circuit and a second terminal connected to the first terminal of the unit to be tested; a voltage divider circuit, with a first terminal connected to the first terminal of the unit to be tested and a second terminal connected to the fourth terminal of the rectifier circuit; a control circuit, with a first terminal connected to the first terminal of the voltage divider circuit and a second terminal connected to the second terminal of the unit to be tested; and a bus voltage filter capacitor, with a first terminal connected to the line between the charging circuit and the voltage divider circuit and a second terminal connected to the line between the rectifier circuit and the voltage divider circuit; wherein the control circuit includes multiple control switches, which are used to control the voltage of the unit to be tested. In other words, the power-on / power-off circuit of this invention can gradually increase the voltage of the detected target in segments. After detecting one detected target, it is not necessary to discharge the bus voltage filter capacitor. When detecting the next detected target, it is not necessary to charge the bus voltage filter capacitor. In actual tests, the production cycle time can be reduced from 8 seconds to 5 seconds, saving 3 seconds of time. This solves the problem in related technologies where the power-on / power-off circuit requires discharging the bus voltage filter capacitor after each detected target and charging it before detecting the next detected target, resulting in long processing time and low production efficiency. This achieves the technical effect of reducing production time and improving production efficiency. Attached Figure Description

[0015] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0016] Figure 1 A schematic diagram of a power-on / power-off circuit provided in the prior art;

[0017] Figure 2 A schematic diagram of a power-on / power-off circuit provided in an embodiment of the present invention;

[0018] Figure 3 A flowchart of a circuit control method provided in an embodiment of the present invention.

[0019] The above figures include the following reference numerals:

[0020] 11. AC input unit; 12. Rectifier circuit; 13. Charging circuit; 14. Bus voltage filter capacitor; 15. Discharge circuit; 16. Unit to be tested; 17. Preset capacitor; 18. Sub-unit to be tested; 21. Voltage divider circuit; 22. Control circuit. Detailed Implementation

[0021] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0022] It should be noted that the terms "first," "second," etc., in the specification, claims, and drawings of this invention are used to distinguish different objects, rather than to limit a specific order.

[0023] This invention provides a power-on power-off circuit. Figure 2 This is a schematic diagram of a power-on / power-off circuit provided in an embodiment of the present invention, as shown below. Figure 2 As shown, the power-on / power-off circuit includes: an AC input unit 11; a detection unit 16; a rectifier circuit 12, the first terminal of which is connected to the first terminal of the AC input unit 11, and the second terminal of which is connected to the second terminal of the AC input unit 11; a charging circuit 13, the first terminal of which is connected to the third terminal of the rectifier circuit 12, and the second terminal of which is connected to the first terminal of the detection unit 16; and a voltage divider circuit 21, the first terminal of which is connected to the first terminal of the detection unit 16, and the second terminal of which is connected to the rectifier circuit 12. The fourth terminal of circuit 12 is connected to: control circuit 22, the first terminal of control circuit 22 is connected to the first terminal of voltage divider circuit 21, and the second terminal of control circuit 22 is connected to the second terminal of the unit to be tested 16; bus voltage filter capacitor 14, the first terminal of bus voltage filter capacitor 14 is connected to the line between charging circuit 13 and voltage divider circuit 21, and the second terminal of bus voltage filter capacitor 14 is connected to the line between rectifier circuit 12 and voltage divider circuit 21; wherein, control circuit 22 includes multiple control switches, which are used to control the voltage of the unit to be tested 16 respectively.

[0024] It should be noted that the aforementioned unit to be detected 16 is the target being detected, which is the controlled object corresponding to the control circuit 22. The control circuit 22 in the above connection mode has three terminals; otherwise, the ground terminal of the control circuit 22 is not connected to the fourth terminal of the rectifier circuit 12.

[0025] In the above embodiment, the power-on / power-off circuit can gradually increase the voltage of the detected target in segments. After detecting one detected target, it is not necessary to discharge the bus voltage filter capacitor 14. When detecting the next detected target, it is not necessary to charge the bus voltage filter capacitor 14. In actual tests, the production cycle time can be reduced from 8 seconds to 5 seconds, saving 3 seconds of time. This solves the problem in the related technology where the power-on / power-off circuit needs to discharge the bus voltage filter capacitor 14 after each detected target and charge it before detecting the next detected target, resulting in long time consumption and low production efficiency. This achieves the technical effect of reducing production time and improving production efficiency.

[0026] Furthermore, since the voltage divider circuit 21 and the control circuit 22 are used together, the voltage control of the unit to be detected 16 can be achieved by any one or more of the multiple control switches, which means that the voltage of the target to be detected can be increased in segments and gradually.

[0027] The voltage divider circuit described above can be composed of a predetermined number of resistors or capacitors. The resistance values ​​of the resistors and capacitors are preferably the same. The specific values ​​of the predetermined numbers can be set according to the application requirements. It should be noted that the number of control switches in the control circuit 22 is related to the specific number of resistors or capacitors in the voltage divider circuit. Therefore, the number of control switches in the control circuit 22 can be adjusted according to the specific number of resistors or capacitors in the voltage divider circuit to improve the voltage control effect of the power-on and power-off circuit.

[0028] In one alternative embodiment, the voltage divider circuit 21 includes a plurality of capacitors, wherein the plurality of capacitors are connected in series in the voltage divider circuit.

[0029] It should be noted that the capacitance values ​​of the aforementioned capacitors can be the same or different. Optionally, the aforementioned capacitors can have the same capacitance value. Further, the capacitors with the same capacitance value are connected in series in a voltage divider circuit. In addition, there is no limitation on the number of capacitors included in the aforementioned voltage divider circuit 21; optionally, there are at least three capacitors.

[0030] The aforementioned capacitor is a device for storing charge and electrical energy, consisting of two electrodes made of closely spaced and insulated conductors. Optionally, the aforementioned capacitor includes, but is not limited to, capacitors with different structures such as fixed capacitors, variable capacitors, and trimmer capacitors. In specific implementations, the appropriate capacitor can be flexibly selected according to application requirements.

[0031] In one optional embodiment, the plurality of capacitors includes at least a first capacitor, a second capacitor, and a third capacitor, wherein a first terminal of the first capacitor is connected to a second terminal of the charging circuit 13, a second terminal of the first capacitor is connected to a first terminal of the second capacitor, a second terminal of the second capacitor is connected to a first terminal of the third capacitor, and a second terminal of the third capacitor is connected to a fourth terminal of the rectifier circuit 12.

[0032] It should be noted that, in the above embodiment, multiple capacitors can be connected in series to form a voltage divider circuit 21.

[0033] In one optional embodiment, the plurality of control switches include at least a first control switch, a second control switch, and a third control switch, wherein a first end of the first control switch is connected to a second end of a third capacitor, a second end of the first control switch is connected to a second end of the unit to be detected 16, a first end of the second control switch is connected to the line between the first control switch and the unit to be detected 16, a second end of the second control switch is connected to the line between the second capacitor and the third capacitor, a first end of the third control switch is connected to the line between the first control switch and the unit to be detected 16, and a second end of the third control switch is connected to the line between the first capacitor and the second capacitor.

[0034] It should be noted that, in the above embodiments, a control circuit 22 consisting of multiple control switches can be implemented.

[0035] In one alternative embodiment, the voltage divider circuit 21 includes a plurality of resistors, wherein the plurality of resistors are connected in series in the voltage divider circuit.

[0036] It should be noted that the resistance values ​​of the aforementioned resistors can be the same or different. Optionally, the aforementioned resistors can have the same resistance value. Further, the resistors with the same resistance value are connected in series to form a voltage divider circuit. In addition, there is no limitation on the number of resistors included in the aforementioned voltage divider circuit 21; optionally, there are at least three resistors.

[0037] The aforementioned resistor is a two-terminal electronic component made of resistive material, with a specific structural form, that functions to limit the flow of current in a circuit. Optionally, the aforementioned resistor includes, but is not limited to, carbon film resistors, metal resistors, wire-wound resistors, fixed resistors, variable resistors, photoresistors, varistors, and thermistors.

[0038] In one alternative embodiment, the plurality of resistors includes at least a first resistor, a second resistor, and a third resistor, wherein a first end of the first resistor is connected to a second end of the charging circuit 13, a second end of the first resistor is connected to a first end of the second resistor, a second end of the second resistor is connected to a first end of the third resistor, and a second end of the third resistor is connected to a fourth end of the rectifier circuit 12.

[0039] It should be noted that, in the above embodiment, multiple resistors connected in series can be used to form a voltage divider circuit 21.

[0040] In one optional embodiment, the plurality of control switches include at least a first control switch, a second control switch, and a third control switch, wherein a first end of the first control switch is connected to a second end of a third resistor, a second end of the first control switch is connected to a second end of the unit to be tested 16, a first end of the second control switch is connected to the line between the first control switch and the unit to be tested 16, a second end of the second control switch is connected to the line between the second resistor and the third resistor, a first end of the third control switch is connected to the line between the first control switch and the unit to be tested 16, and a second end of the third control switch is connected to the line between the first resistor and the second resistor.

[0041] It should be noted that, in the above embodiments, a control circuit 22 consisting of multiple control switches can be implemented.

[0042] In one optional embodiment, the unit to be detected 16 includes at least: a predetermined capacitor 17, an inverter circuit, and a motor, wherein the inverter circuit is connected to the motor, the second terminal of the control circuit 22, the fourth terminal of the rectifier circuit 12, and the second terminal of the charging circuit 13, respectively; the first terminal of the predetermined capacitor is connected to the line between the charging circuit 13 and the inverter circuit; and the second terminal of the predetermined capacitor is connected to the line between the rectifier circuit 12 and the inverter circuit.

[0043] It should be noted that the inverter circuit, after being connected to the motor, can be considered as a sub-unit within the aforementioned unit 16 to be tested. In specific implementation, the aforementioned power-on and power-off circuit can control one or more units 16 to be tested.

[0044] In one optional embodiment, the capacitance value corresponding to the predetermined capacitor is less than the capacitance value corresponding to the bus voltage filter capacitor 14.

[0045] In one optional embodiment, the charging circuit 13 includes at least a fourth operating switch and a fourth resistor, wherein the fourth operating switch and the fourth resistor are connected in parallel to form the charging circuit 13.

[0046] In one alternative implementation, the AC input unit 11 is used to connect to AC power of a predetermined voltage.

[0047] It should be noted that the predetermined voltage connected to the aforementioned AC input unit 11 includes, but is not limited to, 110V, 220V, and 380V, and may also be other voltages.

[0048] According to another aspect of the present invention, a circuit control method is also provided, applied to the power-on / power-off circuit of any of the above-described embodiments, wherein the plurality of control switches include at least a first control switch, a second control switch, and a third control switch. Figure 3 A flowchart of a circuit control method provided in an embodiment of the present invention is shown below. Figure 3 As shown, the specific implementation steps of this method are as follows:

[0049] Step S302: Control the first control switch and the second control switch to be disconnected, close the third control switch, detect the voltage of the unit to be detected, and record the detected voltage of the unit to be detected as the first voltage;

[0050] Step S304: After waiting for the first preset time, control the second control switch to close and the third control switch to open, detect the voltage of the unit to be detected, and record the detected voltage of the unit to be detected as the second voltage.

[0051] Step S306: After waiting for the second preset time, control the first control switch to close and the second control switch to open, detect the voltage of the unit to be detected, and record the detected voltage of the unit to be detected as the third voltage.

[0052] Through the above-described embodiments of the present invention, the control method of this circuit can realize the detection of the voltage of the unit to be detected under different states by controlling multiple control switches. It automatically realizes the detection of the target voltage in segments and gradually increases the voltage of the target to be detected. After detecting one target, it is not necessary to discharge the bus voltage filter capacitor. When detecting the next target, it is not necessary to charge the bus voltage filter capacitor. The actual measurement shows that the production cycle time can be reduced from 8 seconds to 5 seconds, saving 3 seconds of time. This solves the problem in the related technology where the power-on and power-off circuits need to discharge the bus voltage filter capacitor after detecting each target and charge the bus voltage filter capacitor before detecting the next target, which is time-consuming and leads to low production efficiency. It achieves the technical effect of reducing production time and improving production efficiency.

[0053] In one optional embodiment, the aforementioned power-on / power-off circuit is connected to a control device, which includes a memory and a processor. The memory stores a computer program, and the processor is configured to execute the following steps through the computer program: control the disconnection of a first control switch and a second control switch, close a third control switch, detect the voltage of the unit to be detected, and record the detected voltage of the unit to be detected as a first voltage; after waiting for a first preset time, control the closure of the second control switch and the disconnection of the third control switch, detect the voltage of the unit to be detected, and record the detected voltage of the unit to be detected as a second voltage; after waiting for a second preset time, control the closure of the first control switch and the disconnection of the second control switch, detect the voltage of the unit to be detected, and record the detected voltage of the unit to be detected as a third voltage.

[0054] In the specific implementation process, when the test begins, the first control switch and the second control switch are first disconnected and the third control switch is closed. The voltage of the target being tested is 1 / 3 Udc. After waiting for a certain period of time, the second control switch is closed and the third control switch is disconnected. The voltage of the target being tested is 2 / 3 Udc. After waiting for a certain period of time again, the first control switch is closed and the second control switch is disconnected. In this way, the voltage of the target being tested is Udc.

[0055] It should be noted that the first and second preset times mentioned above can be set according to the needs of specific application scenarios, and will not be elaborated on here.

[0056] According to another aspect of the present invention, a brushless DC motor is also provided, the brushless DC motor including any of the above-described power-on and power-off circuits.

[0057] Optionally, a power-on / power-off circuit of any one of the above can be set in the brushless DC motor to realize the relevant control of the brushless DC motor. The brushless DC motor can be composed of a motor body and a driver, wherein the driver includes power electronic devices and integrated circuits. The driver can control the motor's starting, stopping and braking functions based on the power-on / power-off circuit.

[0058] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention.

Claims

1. A power-on reset circuit, comprising: The utility model relates to a kind of voltage detection circuit, including: AC input unit; To be detected unit; Rectifier circuit, the first end of the rectifier circuit is connected with the first end of the AC input unit, and the second end of the rectifier circuit is connected with the second end of the AC input unit; Charging circuit, the first end of the charging circuit is connected with the third end of the rectifier circuit, and the second end of the charging circuit is connected with the first end of the to be detected unit; Voltage dividing circuit, the first end of the voltage dividing circuit is connected with the first end of the to be detected unit, and the second end of the voltage dividing circuit is connected with the fourth end of the rectifier circuit; Control circuit, the first end of the control circuit is connected with the first end of the voltage dividing circuit, and the second end of the control circuit is connected with the second end of the to be detected unit; Bus voltage filter capacitor, the first end of the bus voltage filter capacitor is connected to the line between the charging circuit and the voltage dividing circuit, and the second end of the bus voltage filter capacitor is connected to the line between the rectifier circuit and the voltage dividing circuit; Wherein, the control circuit includes multiple control switches, and multiple control switches are used to control the voltage of the to be detected unit respectively; The voltage dividing circuit includes multiple capacitors, wherein multiple capacitors are connected in series in sequence to form the voltage dividing circuit;Multiple capacitors at least include first capacitor, second capacitor and third capacitor, wherein the first end of the first capacitor is connected with the second end of the charging circuit, the second end of the first capacitor is connected with the first end of the second capacitor, the second end of the second capacitor is connected with the first end of the third capacitor, and the second end of the third capacitor is connected with the fourth end of the rectifier circuit;Multiple control switches at least include first control switch, second control switch and third control switch, wherein the first end of the first control switch is connected with the second end of the third capacitor, the second end of the first control switch is connected with the second end of the to be detected unit, the first end of the second control switch is connected to the line between the first control switch and the to be detected unit, the second end of the second control switch is connected to the line between the second capacitor and the third capacitor, the first end of the third control switch is connected to the line between the first control switch and the to be detected unit, and the second end of the third control switch is connected to the line between the first capacitor and the second capacitor. Alternatively, the voltage dividing circuit comprises a plurality of resistors, wherein the plurality of resistors are connected in series to form the voltage dividing circuit; the plurality of resistors comprise at least a first resistor, a second resistor and a third resistor, wherein a first end of the first resistor is connected to the second end of the charging circuit, a second end of the first resistor is connected to a first end of the second resistor, a second end of the second resistor is connected to a first end of the third resistor, and a second end of the third resistor is connected to the fourth end of the rectifier circuit; the plurality of control switches comprise at least a first control switch, a second control switch and a third control switch, wherein a first end of the first control switch is connected to the second end of the third resistor, a second end of the first control switch is connected to the second end of the to-be-detected unit, a first end of the second control switch is connected to a line between the first control switch and the to-be-detected unit, a second end of the second control switch is connected to a line between the second resistor and the third resistor, a first end of the third control switch is connected to a line between the first control switch and the to-be-detected unit, and a second end of the third control switch is connected to a line between the first resistor and the second resistor. The first control switch and the second control switch are first disconnected, the third control switch is closed, the voltage of the to-be-detected unit is 1 / 3 Udc, a certain period of time is waited, the second control switch is closed and the third control switch is disconnected, the voltage of the to-be-detected unit is 2 / 3 Udc, a certain period of time is waited, the first control switch is closed and the second control switch is disconnected, and the voltage of the to-be-detected unit is Udc.

2. The power-on power-off circuit of claim 1, wherein, The to-be-detected unit comprises a predetermined capacitor, an inverter circuit and a motor, wherein the inverter circuit is connected to the motor, the second end of the control circuit, the fourth end of the rectifier circuit and the second end of the charging circuit respectively, the first end of the predetermined capacitor is connected to a line between the charging circuit and the inverter circuit, and the second end of the predetermined capacitor is connected to a line between the rectifier circuit and the inverter circuit.

3. The power-on power-off circuit of claim 2, wherein, The predetermined capacitor corresponds to a capacitance value smaller than a capacitance value corresponding to the bus voltage filtering capacitor.

4. The power-on / off circuit according to any one of claims 1 to 3, characterized by The charging circuit comprises at least a fourth operating switch and a fourth resistor, wherein the fourth operating switch and the fourth resistor are connected in parallel to form the charging circuit.

5. A control method of a power-on / off circuit according to any one of claims 1 to 4, characterized by, The plurality of control switches comprise at least a first control switch, a second control switch and a third control switch, and the method comprises: controlling the first control switch and the second control switch to be disconnected and the third control switch to be closed, detecting the voltage of the to-be-detected unit, and recording the detected voltage of the to-be-detected unit as a first voltage; after waiting for a first preset time, controlling the second control switch to be closed and the third control switch to be disconnected, detecting the voltage of the to-be-detected unit, and recording the detected voltage of the to-be-detected unit as a second voltage; After waiting for a second preset time, the first control switch is closed and the second control switch is opened, the voltage of the unit to be detected is detected, and the detected voltage of the unit to be detected is recorded as a third voltage.

6. A brushless DC motor, characterized by The brushless DC motor comprises the power-on and power-off circuit according to any one of claims 1 to 4.

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