Power supply device of motor protector and power supply method thereof

Abstract

The present disclosure relates to a power supply device of a motor protector and a power supply method thereof. The motor protector receives electric energy by inducing the alternating current in the power supply line of the motor through a power supply coil and converting the induced alternating current into direct current using a rectifier, and the power supply device includes: a first power supply unit, receiving and storing the electric energy, and supplying power to a tripping device of the motor protector; a second power supply unit, receiving the electric energy, and supplying power to a calculation and control device of the motor protector; a third power supply unit, receiving and storing the electric energy, and supplying power to a reclosing device of the motor protector; and a control unit, controlling the order in which the first power supply unit, the second power supply unit, and the third power supply unit receive the electric energy, so that the first power supply unit first receives the electric energy, then the second power supply unit receives the electric energy, and finally the third power supply unit receives the electric energy.

Description

Technical Field

[0001] The present disclosure relates to a power supply device for a motor protector and a power supply method thereof, and in particular to a power supply device for a motor protector which can more quickly realize a ground fault protection function while taking into account an automatic reclosing function and a power supply method thereof. Background Art

[0002] Motor protectors are usually used to start and protect motors. The protection functions of motor protectors may include thermal overload protection, ground fault protection, phase loss protection, etc. When the insulation of the motor fails and a current to the ground is generated, ground fault protection needs to be performed. The purpose of ground fault protection is to prevent further insulation failure and eventually cause a short circuit fault, so the protection requires a short response time. For example, in the IEC 60947-1 standard for low-voltage switchgear and controlgear developed by the International Electrotechnical Commission (IEC), it is required that Class A equipment be tripped within 1 second at 1.1 times the ground fault protection threshold.

[0003] Motor protectors that provide ground fault protection can be powered by an auxiliary power supply or self-powered. Motor protectors powered by an auxiliary power supply require the customer to provide additional power on site and add additional wiring. Self-powered motor protectors are usually powered by current, and the amount of power they can receive and the time it takes to start and complete the protection function are affected by the load current of the motor. Summary of the invention

[0004] The present disclosure relates to a power supply device of a motor protector and a power supply method thereof, which can start more quickly and realize a ground fault protection function while taking into account the automatic reclosing function of the motor protector under a thermal overload condition.

[0005] According to one aspect of the present disclosure, a power supply device of a motor protector is provided, wherein the motor protector receives electric energy by inducing the alternating current in the power supply line of the motor via a power supply coil and converting the induced alternating current into direct current using a rectifier, and the power supply device comprises: a first power supply unit, receiving and storing the electric energy, and supplying power to a tripping device of the motor protector; a second power supply unit, receiving the electric energy, and supplying power to a calculation and control device of the motor protector; a third power supply unit, receiving and storing the electric energy, and supplying power to a reclosing device of the motor protector; and a control unit, controlling the order in which the first power supply unit, the second power supply unit, and the third power supply unit receive the electric energy, so that the electric energy is first received by the first power supply unit, then by the second power supply unit, and finally by the third power supply unit.

[0006] According to another aspect of the present disclosure, a power supply method for a power supply device of a motor protector is provided, wherein the motor protector receives electric energy by inducing alternating current in a power supply line of a motor via a power supply coil and converting the induced alternating current into direct current using a rectifier, wherein the power supply device comprises a first power supply unit, a second power supply unit, a third power supply unit and a control unit, and the power supply method comprises: receiving and storing the electric energy by the first power supply unit, and supplying power to a tripping device of the motor protector; receiving the electric energy by the second power supply unit, and supplying power to a calculation and control device of the motor protector; receiving and storing the electric energy by the third power supply unit, and supplying power to a reclosing device of the motor protector, wherein the control unit controls the order in which the first power supply unit, the second power supply unit and the third power supply unit receive the electric energy, so that the first power supply unit first receives the electric energy, then the second power supply unit receives the electric energy, and finally the third power supply unit receives the electric energy.

[0007] According to the embodiment of the present disclosure, the first, second and third power supply units are provided to supply power to the tripping device, the calculation and control device and the reclosing device of the motor protector respectively. By controlling the order in which the first, second and third power supply units receive electric energy, the first power supply unit associated with the tripping device realizing the ground fault protection function can be given the highest energy storage priority, so that even in the case of a small rated current, the ground fault protection function can be started more quickly and realized; at the same time, according to the embodiment of the present disclosure, the energy storage of the reclosing device associated with the automatic reclosing function of the motor protector under thermal overload conditions is taken into account, so that the automatic reclosing function can be taken into account while realizing the ground fault protection function. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The aspects, features and advantages of the present disclosure will become clearer and easier to understand through the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0009] Figure 1 is a schematic circuit module diagram of a self-powered motor protector according to an embodiment of the present disclosure;

[0010] Figure 2 is a schematic circuit module diagram of a power supply device according to an embodiment of the present disclosure;

[0011] Figure 3 is a schematic circuit module diagram of a power supply device according to another embodiment of the present disclosure;

[0012] Figure 4 A schematic circuit diagram showing a power supply device according to an embodiment of the present disclosure;

[0013] Figure 5A flowchart showing the working process of the power supply device according to an embodiment of the present disclosure; and

[0014] Figure 6 A flow chart of a power supply method of a power supply device of a motor protector according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0015] The present disclosure will be described in detail below with reference to exemplary embodiments of the present disclosure. However, the present disclosure is not limited to the embodiments described herein, and it can be implemented in many different forms. The described embodiments are only used to make the present disclosure thorough and complete, and to fully convey the concept of the present disclosure to those skilled in the art. The features of the various embodiments described can be combined or replaced with each other, unless explicitly excluded or should be excluded according to the context.

[0016] The self-powered motor protector receives electric energy via the power supply coil, thereby supplying power to various circuits or devices in the motor protector. Specifically, the three-phase alternating current in the power supply line of the motor is induced by the three-phase current transformer (i.e., the power supply coil) of the motor protector, and then the rectifier of the motor protector converts the induced alternating current into direct current, which is then used to supply power to various circuits or devices in the motor protector. Therefore, the electric energy that the self-powered motor protector can receive, and the time to start and complete the protection function are related to the load current of the motor. For example, when the load current is the minimum rated current, the output power of the power supply coil is only 100mW, while the driving power required for the tripping device in the motor protector is about 600mW, so it cannot be guaranteed that the tripping is completed when a ground fault occurs.

[0017] The embodiment of the present disclosure proposes a power supply device for a motor protector, and a first, a second, and a third power supply unit are provided to supply power to a tripping device, a computing and controlling device, and a reclosing device of the motor protector, respectively. The first power supply unit is associated with a tripping device for realizing a ground fault protection function, and is capable of pre-storing electric energy for tripping. By controlling the order in which the first, the second, and the third power supply units receive electric energy, the first power supply unit can be given the highest energy storage priority, so that even when the rated current is small, it can be started more quickly (for example, within 1 second) and realize the ground fault protection function. In addition, according to the embodiment of the present disclosure, the third power supply unit is associated with a reclosing device for realizing an automatic reclosing function of the motor protector under thermal overload conditions, and is capable of pre-storing electric energy for automatic reclosing, so that the automatic reclosing function can be taken into account while realizing the ground fault protection function.

[0018] Figure 1 FIG. 1 is a schematic circuit module diagram of a self-powered motor protector 100 according to an embodiment of the present disclosure. Figure 1As shown, the motor protector 100 includes a power supply coil 110, a rectifier 120, a power supply device 130, a tripping device 140, a calculation and control device 150 and a reclosing device 160. The power supply coil 110 senses the three-phase alternating current in the power supply line of the motor, and then the rectifier 120 converts the induced alternating current into direct current. The power supply device 130 receives the direct current and then supplies power to the tripping device 140, the calculation and control device 150 and the reclosing device 160 in the motor protector 100 respectively. The tripping device 140 is used to realize the tripping function in the case of a fault or overload. The calculation and control device 150 can be, for example, a microcontroller unit (MCU), which is used for calculating the ground fault current, determining whether a fault occurs, controlling whether to drive the tripping device 140, and other calculation and control logic processing. The reclosing device 160 is used to realize the automatic reclosing function after a predetermined time in the case of tripping due to thermal overload.

[0019] Figure 2 is a schematic circuit module diagram of a power supply device 200 of a motor protector according to an embodiment of the present disclosure. The power supply device 200 may include a first power supply unit 210, which receives and stores electric energy and supplies power to a tripping device 140 of the motor protector. As described above, when the load current is the minimum rated current, the output power of the power supply coil may not be able to meet the driving power required by the tripping device in the motor protector, thereby failing to ensure that the tripping is completed when a ground fault occurs. Therefore, it is necessary to store the electric energy for tripping in advance. In one embodiment, as Figure 2 As shown, the first power supply unit 210 may include a first energy storage subunit 2101, which is used to receive electrical energy to store electrical energy, and use the stored electrical energy to power the trip device 140 of the motor protector, thereby ensuring that when a ground fault occurs, there is sufficient driving power to drive the trip device 140.

[0020] The power supply device 200 may further include a second power supply unit 220, which receives electric energy and supplies power to the calculation and control device 150 of the motor protector. As described above, the calculation and control device 150 may be a microcontroller unit (MCU). For the MCU, its power supply voltage is usually 3.3V. Therefore, it is necessary to step down the input voltage to about 3.3V to provide it to the MCU. In one embodiment, Figure 2 As shown, the second power supply unit 220 may include a first power supply subunit 2201 for receiving electric energy and supplying power to the computing and control device 150 with a first output voltage (e.g., 3.3V) required by the computing and control device 150. The first output voltage may be set according to the actual configuration of the circuit.

[0021] As described above, the motor protector according to the present disclosure can achieve the automatic reclosing function while realizing the ground fault protection function. Therefore, the power supply device 200 may further include a third power supply unit 230 that receives and stores electric energy and supplies power to the reclosing device 160 of the motor protector. After the tripping device 140 trips, the motor stops running, and the power supply coil 110 cannot sense current, so there is no power supply current for the motor protector. Therefore, it is necessary to pre-store the electric energy for automatic reclosing. In one embodiment, as Figure 2 shown, the third power supply unit 230 may include a second energy storage subunit 2302 for storing electric energy and supplying the stored electric energy to the reclosing device 160. In addition, since the driving power required by the reclosing device 160 is relatively large, the second energy storage subunit 2302 requires a relatively large input voltage. In this case, the third power supply unit 230 may further include a second power supply subunit 2301 for receiving electric energy and supplying power to the second energy storage subunit 2302 at a second output voltage (e.g., 30V or greater) required by the second energy storage subunit 2302, and the second output voltage may be set according to the actual configuration of the circuit. In yet another embodiment, to avoid excessive instantaneous current flowing into the second power supply subunit 2301, as Figure 2 shown, the third power supply unit 230 may further include a current limiting circuit 2303. The current limiting circuit 2303 is connected between the second power supply subunit 2301 and the rectifying device 120 (e.g., connected to the rectifying device 120 via the control unit 240) so that the current flowing from the rectifying device 120 into the second power supply subunit 2301 is less than or equal to a first current threshold Cth1. The first current threshold Cth1 may be set according to the actual configuration of the circuit.

[0022] According to an embodiment of the present disclosure, a first power supply unit 210, a second power supply unit 220, and a third power supply unit 230 are respectively provided in the power supply device 200 to supply power to the tripping device 140, the calculation and control device 150, and the reclosing device 160 of the motor protector. However, as described above, in, for example, the standard IEC 60947-1, requirements are also imposed on the tripping time (e.g., within 1 second). If there is no limit on the power supply time for the tripping device 140, the calculation and control device 150, and the reclosing device 160, such as powering them simultaneously, it will inevitably affect the energy storage time of the first energy storage subunit 2101, thereby affecting the time to start and implement the ground fault protection.

[0023] To be able to implement the ground fault protection function more quickly, the power supply device according to the embodiment of the present disclosure also controls the timing of receiving electric energy for the first power supply unit 210, the second power supply unit 220, and the third power supply unit 230.

[0024] As mentioned above, the ground fault protection function requires a short tripping time, so from the perspective of power supply, the first power supply unit 210 should be given the highest priority so that it can receive and store full power as soon as possible. Full power storage here means that even if the power supply coil does not provide current at all, the stored power is sufficient to drive the tripping device.

[0025] Secondly, only when the calculation and control device 150 is in operation can the ground fault current be calculated, whether a fault occurs, whether the trip device 140 is driven, etc. Therefore, from the power supply perspective, the second power supply unit 220 should be given priority after the first power supply unit 210.

[0026] Finally, the automatic reclosing function is only allowed to be executed when the tripping is caused by thermal overload, and the automatic reclosing function does not need to be executed when only a ground fault occurs. For overload protection, when the overload current is small (for example, 1.2 times the rated current), the cold tripping time is approximately 30 minutes to 2 hours, and the hot tripping time is also greater than 1 minute, so it is allowed to delay the power supply to the third power supply unit 230. When the overload current is large (for example, 7.2 times the rated current), the power supply capacity of the power supply coil is strong enough to enable the first power supply unit 210 to quickly complete energy storage and supply power to the second power supply unit 220, and enable the third power supply unit 230 to start receiving electrical energy. In addition, before executing the automatic reclosing function, it is also necessary for the MCU to judge conditions such as the real-time current size, the current thermal capacity value, the power-on time, etc., and the automatic reclosing will be executed only when all conditions are met. Therefore, from the power supply perspective, the third power supply unit 230 has the lowest priority.

[0027] Therefore, if Figure 2 As shown, the power supply device 200 may further include a control unit 240 for controlling the order in which the first power supply unit 210, the second power supply unit 220, and the third power supply unit 230 receive electric energy, so that the first power supply unit 210 receives electric energy first, then the second power supply unit 220 receives electric energy, and finally the third power supply unit 230 receives electric energy, so that even when the rated current is small, it can start more quickly and realize the ground fault protection function, while also taking into account the automatic reclosing function.

[0028] In one embodiment, if Figure 2As shown, the above-mentioned timing control is realized by setting a first control subunit 2401 and a second control subunit 2402 in the control unit. The first control subunit 2401 is connected between the rectifier 120 and the second power supply unit 220. Specifically, the first input end of the first control subunit 2401 is connected to the output end of the rectifier 120, and the output end is connected to the second power supply unit 220. Only when the voltage of the first input end of the first control subunit 2401 is greater than the first voltage threshold Vth1, the first control subunit 2401 controls the second power supply unit 220 to start receiving electric energy. When the voltage of the first input end of the first control subunit 2401 is greater than the first voltage threshold Vth1, it indicates that the first power supply unit 210 has completed energy storage, so that the second power supply unit 220 can start receiving electric energy, thereby ensuring that the first power supply unit 210 receives electric energy before the second power supply unit 220.

[0029] The second control subunit 2402 is connected between the rectifier 120 and the third power supply unit 230. Specifically, the first input terminal of the second control subunit 2402 is connected to the output terminal of the rectifier 120, and the output terminal is connected to the third power supply unit 230. Only when the voltage of the first input terminal of the second control subunit 2402 is greater than the second voltage threshold Vth2, the second control subunit 2402 controls the third power supply unit 230 to start receiving electric energy. The second voltage threshold Vth2 can be greater than the first voltage threshold Vth1, thereby ensuring that the second power supply unit 220 receives electric energy before the third power supply unit 230.

[0030] In the case where the second power supply unit 220 and / or the third power supply unit 230 have already started to receive electric energy, the power supply capacity of the power supply coil may also decrease for some reason, which may affect the normal operation of the first power supply unit. For example, when the power supply capacity of the power supply coil decreases and is insufficient to supply power to the second power supply unit 220 and / or the third power supply unit 230, the second power supply unit 220 and / or the third power supply unit 230 may draw power from the power stored in the first power supply unit 210, thereby affecting the normal operation of the first power supply unit 210. In order to avoid this situation, the control unit 240 can also limit the timing when the second power supply unit 220 and the third power supply unit 230 stop receiving electric energy. In one embodiment, when the voltage at the first input terminal of the first control subunit 2401 is less than the third voltage threshold Vth3, the first control subunit 2401 controls the second power supply unit 220 to stop receiving electric energy. The third voltage threshold Vth3 may be less than or equal to the first voltage threshold Vth1, that is, the voltage thresholds used to control the second power supply unit 220 to start and stop receiving electric energy may be the same or different. Relative to the case where the third voltage threshold Vth3 is equal to the first voltage threshold Vth1, when the third voltage threshold Vth3 is less than the first voltage threshold Vth1, the time for controlling the second power supply unit 220 to receive electric energy can be extended. In another embodiment, when the voltage at the first input terminal of the second control subunit 2402 is less than the fourth voltage threshold Vth4, the second control subunit 2402 controls the third power supply unit 230 to stop receiving electric energy. The fourth voltage threshold Vth4 may be less than or equal to the second voltage threshold Vth2, that is, the voltage thresholds for controlling the third power supply unit 230 to start and stop receiving electric energy may be the same or different. Relative to the case where the fourth voltage threshold Vth4 is equal to the second voltage threshold Vth2, when the fourth voltage threshold Vth4 is less than the second voltage threshold Vth2, the time for controlling the third power supply unit 230 to receive electric energy can be extended. The fourth voltage threshold Vth4 may be greater than the third voltage threshold Vth3, so that when the power supply capacity of the power supply coil is insufficient, the third power supply unit 230 is first stopped from receiving electric energy, and when the power supply capacity of the power supply coil continues to deteriorate, the second power supply unit 220 is stopped from receiving electric energy.

[0031] In another embodiment, in order to ensure that the first and third power supply units can store electric energy respectively and reduce the influence between the first to third power supply units (ie, anti-reverse connection function), an anti-reverse connection unit may be added, such as Figure 3 shown. Figure 3 is a schematic circuit module diagram of a power supply device 300 according to another embodiment of the present disclosure, Figure 3 and Figure 2 The difference is Figure 3The power supply device 300 in the embodiment further includes a first anti-reverse connection unit 350, a second anti-reverse connection unit 360 and a third anti-reverse connection unit 370. The input end of the first anti-reverse connection unit 350 is connected to the output end of the rectifier device 120, and the output end of the first anti-reverse connection unit 350 is respectively connected to the input end of the second anti-reverse connection unit 360 and the input end of the third anti-reverse connection unit 370, so as to provide anti-reverse connection for the entire power supply device. The output end of the second anti-reverse connection unit 360 is connected to the first power supply unit 210, so as to provide further anti-reverse connection for it. The input end and the output end of the third anti-reverse connection unit 370 are respectively connected to the control unit 240, specifically, the output end of the third anti-reverse connection unit 370 is respectively connected to the first input end and the second input end of the first control subunit 2401, so as to provide further anti-reverse connection for the subsequent second power supply unit 220. In addition, in one embodiment, an additional anti-reverse connection unit can be provided in the current limiting circuit 2303 included in the third power supply unit 230 to provide further anti-reverse connection for the third power supply unit 230. In another embodiment, the output end of the third anti-reverse connection unit 370 may also be connected to the first input end and the second input end of the second control subunit 2402, respectively, so as to provide further anti-reverse connection for the subsequent third power supply unit 230. In another embodiment, an additional anti-reverse connection unit may be provided in each of the first to third power supply units to provide further anti-reverse connection. Figure 3 As shown, when various anti-reverse polarity units are set up, the first input end of the second control subunit 2402 can be connected to the output end of the third anti-reverse polarity unit 370, and the second input end of the second control subunit 2402 can be connected to the input end of the third anti-reverse polarity unit 370, thereby controlling the reception of electrical energy by the third power supply unit 230.

[0032] In another embodiment, in order to prevent the current and voltage flowing from the power supply coil into the power supply device from being too large, thereby causing damage to the components in the power supply device, a protection unit 380 may be added, such as Figure 3As shown. The first input end of the protection unit 380 is connected to the output end of the first anti-reverse connection unit 350, the second input end is connected to the output end of the rectifier device 120, and the output end of the protection unit 380 is connected to the reference ground. When the current voltage flowing from the power supply coil into the power supply device is too large and causes the voltage of the first input end of the protection unit 380 to be greater than the fifth voltage threshold Vth5, the protection unit 380 can discharge the excessive current voltage to the reference ground, so that the first power supply unit 210, the second power supply unit 220, and the third power supply unit 230 stop receiving electric energy. In the case where the first power supply unit 210, the second power supply unit 220, and the third power supply unit 230 stop receiving electric energy, when the voltage of the first input end of the protection unit 380 is less than the sixth voltage threshold Vth6 due to the release of the electric energy stored in the first and third power supply units, the first power supply unit 210, the second power supply unit 220, and the third power supply unit 230 can resume receiving electric energy. That is, when the voltage at the first input terminal of the protection unit 380 is less than the sixth voltage threshold Vth6, the protection unit 380 can enable the first power supply unit 210 to start receiving electric energy, so that the second power supply unit 220 and the third power supply unit 230 can also subsequently receive electric energy based on the control of the control unit 240. The sixth voltage threshold Vth6 can be less than the fifth voltage threshold Vth5, thereby ensuring that the components in the power supply device are protected from damage.

[0033] According to the above-mentioned embodiment of the present disclosure, the first, second and third power supply units are provided in the power supply device of the self-powered motor protector to respectively supply power to the tripping device, the computing and control device and the reclosing device of the motor protector. By controlling the order in which the first, second and third power supply units receive electric energy, the first power supply unit can be given the highest energy storage priority, so that even when the rated current is small, it can be started more quickly (for example, within 1 second) and realize the ground fault protection function. In addition, the third power supply unit can pre-store electric energy for automatic reclosing, so that the automatic reclosing function can be taken into account while realizing the ground fault protection function.

[0034] Each unit of the power supply device disclosed in the present invention may be implemented by various specific circuits. Figure 4 FIG. 4 is a schematic circuit diagram of a power supply device 400 according to an embodiment of the present disclosure. Figure 4 The specific structures of each unit in the embodiment can be applied separately or replaced by other suitable structures.

[0035] like Figure 4As shown, the first anti-reverse connection unit 450, the second anti-reverse connection unit 460, and the third anti-reverse connection unit 470 can be a first diode D1, a second diode D2, and a third diode D3, respectively. The anode of the first diode D1 is connected to the rectifier 120, and the cathode is connected to the anodes of the second diode D2 and the third diode D3, respectively, for providing anti-reverse connection for the entire power supply device. The cathode of the second diode D2 is connected to the first power supply unit 410 to provide further anti-reverse connection for it. The cathode of the third diode D3 is respectively connected to the first and second input terminals of the first control subunit 4401, thereby providing further anti-reverse connection for the subsequent second power supply unit 420. The cathode of the third diode D3 is also connected to the first input terminal of the second control subunit 4402, and the anode of the third diode D3 is also connected to the second input terminal of the second control subunit 4402.

[0036] The first energy storage subunit included in the first power supply unit 410 may be a capacitor C1, which is connected between the second anti-reverse connection unit 460 and the trip device 140 to receive and store electrical energy, and use the stored electrical energy to supply power to the trip device 140. The capacitance value of the capacitor C1 may be set according to the actual configuration of the circuit. It should be noted that although Figure 4 The first energy storage subunit is shown as a capacitor C1 , however, the first energy storage subunit is not limited to a capacitor. In one embodiment, the first energy storage subunit may also be an energy storage battery.

[0037] The first power supply subunit included in the second power supply unit 420 may be a step-down circuit BUCK, connected between the first control subunit 4401 and the computing and control device 150, for receiving electric energy and supplying power to the computing and control device 450 at a first output voltage required by the computing and control device 450. The first output voltage may be set according to the actual configuration of the circuit.

[0038] The current limiting circuit included in the third power supply unit 430 may be a common current limiter CL, connected between the second control subunit 4402 and the second power supply subunit, so that the current flowing from the rectifier 120 into the second power supply subunit is less than or equal to the first current threshold Cth1. The first current threshold Cth1 may be set according to the actual configuration of the circuit. As described above, in one embodiment, the current limiting circuit included in the third power supply unit 430 may also be a combination of the current limiter CL and the anti-reverse connection unit.

[0039] The second power supply subunit included in the third power supply unit 430 can be a boost circuit BOOST, which is connected between the current limiting circuit and the second energy storage subunit to receive electrical energy and supply power to the second energy storage subunit with a second output voltage required by the second energy storage subunit. The second output voltage can be set according to the actual configuration of the circuit.

[0040] The second energy storage subunit included in the third power supply unit 430 may be a capacitor C2, connected between the second power supply subunit and the reclosing device 160, for receiving and storing electric energy, and using the stored electric energy to supply power to the reclosing device 160. The capacitance value of the capacitor C2 may be set according to the actual configuration of the circuit. It should be noted that although Figure 4 The second energy storage subunit is shown as a capacitor C2, but the second energy storage subunit is not limited to a capacitor. In one embodiment, the second energy storage subunit may also be an energy storage battery.

[0041] The first control subunit 4401 may include a first hysteresis voltage comparison circuit VC1 and a first electronic switch SW1. The first electronic switch SW1 is connected between the output end of the third anti-reverse connection unit 470 and the second power supply unit 420, the input end of the first hysteresis voltage comparison circuit VC1 is connected to the output end of the third anti-reverse connection unit 470, and the output end of the first hysteresis voltage comparison circuit VC1 is connected to the control end of the first electronic switch SW1. The input end of the first hysteresis voltage comparison circuit VC1 corresponds to the first input end of the first control subunit 4401, one end of the first electronic switch SW1 connected to the output end of the third anti-reverse connection unit 470 corresponds to the second input end of the first control subunit 4401, and one end of the first electronic switch SW1 connected to the second power supply unit 420 corresponds to the output end of the first control subunit 4401.

[0042] The hysteresis voltage comparison circuit is a special voltage comparison circuit whose transmission characteristic has the shape of a "hysteresis" curve. The hysteresis voltage comparison circuit has two unequal thresholds. For example, when the input voltage gradually increases to the first threshold, the hysteresis voltage comparison circuit can output a high level; and when the input voltage gradually decreases to the second threshold, the hysteresis voltage comparison circuit can output a low level. In the embodiment of the present disclosure, when the voltage at the input end of the first hysteresis voltage comparison circuit VC1 is greater than the first voltage threshold Vth1, the output end of the first hysteresis voltage comparison circuit VC1 outputs a control signal to close the first electronic switch SW1 so that the second power supply unit 420 starts to receive electrical energy; when the voltage at the input end of the first hysteresis voltage comparison circuit VC1 is less than the third voltage threshold Vth3, the output end of the first hysteresis voltage comparison circuit outputs a control signal to disconnect the first electronic switch SW1 so that the second power supply unit 420 stops receiving electrical energy. The first voltage threshold Vth1 is greater than the third voltage threshold Vth3.

[0043] There are many commonly used electronic switches, such as IGBT, GTO (gate turn-off thyristor), triode, MOS (metal oxide semiconductor) tube, etc., and technicians in this field can choose according to the actual application scenario. For example, in the embodiment of the present disclosure, when the first electronic switch SW1 is a MOS tube, its gate is the control end, which is connected to the output end of the first hysteresis voltage comparison circuit VC1; its source and drain are respectively connected to the second power supply unit 420 (the input end of the buck circuit BUCK) and the output end of the third anti-reverse connection unit 470 (the third diode D3).

[0044] The second control subunit 4402 includes a second hysteresis voltage comparison circuit VC2 and a second electronic switch SW2. The second electronic switch SW2 is connected between the input end of the third anti-reverse connection unit 470 and the third power supply unit 430. The input end of the second hysteresis voltage comparison circuit VC2 is connected to the output end of the third anti-reverse connection unit 470. The output end of the second hysteresis voltage comparison circuit VC2 is connected to the control end of the second electronic switch SW2. The input end of the second hysteresis voltage comparison circuit VC2 corresponds to the first input end of the second control subunit 4402. One end of the second electronic switch SW2 connected to the input end of the third anti-reverse connection unit 470 corresponds to the second input end of the second control subunit 4402. One end of the second electronic switch SW2 connected to the third power supply unit 430 corresponds to the output end of the second control subunit 4402. In the embodiment of the present disclosure, when the voltage at the input end of the second hysteresis voltage comparison circuit VC2 is greater than the second voltage threshold Vth2, the output end of the second hysteresis voltage comparison circuit VC2 outputs a control signal to close the second electronic switch SW2, so that the third power supply unit 430 starts to receive power; when the voltage at the input end of the second hysteresis voltage comparison circuit VC2 is less than the fourth voltage threshold Vth4, the output end of the second hysteresis voltage comparison circuit VC2 outputs a control signal to open the second electronic switch SW2, so that the third power supply unit 430 stops receiving power. The second voltage threshold Vth2 is greater than the fourth voltage threshold Vth4.

[0045] In the embodiment of the present disclosure, when the second electronic switch SW2 is a MOS tube, its gate is the control end, connected to the output end of the second hysteresis voltage comparison circuit VC2; its source and drain are respectively connected to the input end of the third power supply unit 430 (the input end of the current limiter CL) and the third anti-reverse connection unit 470 (the third diode D3).

[0046] The protection unit 480 may include a third hysteresis voltage comparison circuit VC3 and a third electronic switch SW3, wherein the third electronic switch SW3 is connected between the output terminal of the rectifying device 120 and the reference ground, the input terminal of the third hysteresis voltage comparison circuit VC3 is connected to the output terminal of the first anti-reverse connection unit 450, and the output terminal of the third hysteresis voltage comparison circuit VC3 is connected to the control terminal of the third electronic switch SW3. The input terminal of the third hysteresis voltage comparison circuit VC3 corresponds to the first input terminal of the protection unit 480, one end of the third electronic switch SW3 connected to the output terminal of the rectifying device 120 corresponds to the second input terminal of the protection unit 480, and one end of the third electronic switch SW3 connected to the reference ground corresponds to the output terminal of the protection unit 480.

[0047] In the embodiment of the present disclosure, when the voltage at the input end of the third hysteresis voltage comparison circuit VC3 is greater than the fifth voltage threshold Vth5, the output end of the third hysteresis voltage comparison circuit VC3 outputs a control signal to close the third electronic switch SW3, discharges the excessive current voltage to the reference ground, and stops the first power supply unit 410, the second power supply unit 420, and the third power supply unit 430 from receiving electric energy; when the voltage at the input end of the third hysteresis voltage comparison circuit VC3 is less than the sixth voltage threshold Vth6, the output end of the third hysteresis voltage comparison circuit VC3 outputs a control signal to disconnect the third electronic switch SW3, so that the first power supply unit 410 can start receiving electric energy, and thus the second power supply unit 420 and the third power supply unit 430 can also receive electric energy based on the control of the control unit 440. The fifth voltage threshold Vth5 is greater than the sixth voltage threshold Vth6.

[0048] In the embodiment of the present disclosure, when the third electronic switch SW3 is a MOS tube, its gate is the control terminal connected to the output terminal of the third hysteresis voltage comparison circuit VC3; its source and drain are respectively connected to the reference ground and the output terminal of the rectifier 120.

[0049] Figure 5 The working flow diagram of the power supply device according to the embodiment of the present disclosure is shown. Figure 4 The structure of the power supply device Figure 5The flowchart is briefly described below. At S5010, the motor starts, and electric energy begins to be input into the power supply device. At S5020, the protection unit 380 of the power supply device continuously determines whether the voltage at the output end of the first anti-reverse connection unit 450 is greater than the fifth voltage threshold value Vth5. If it is determined that the voltage is not greater than the fifth voltage threshold value Vth5, then at S5040, the first power supply unit 210 begins to receive electric energy; otherwise, if it is determined that the voltage is greater than the fifth voltage threshold value Vth5, the protection unit 380 makes it impossible for the first power supply unit 210, the second power supply unit 220, and the third power supply unit 230 to receive electric energy, thereby preventing excessive current and voltage from causing damage to the power supply device. In addition, if the first power supply unit 210, the second power supply unit 220, and the third power supply unit 230 do not receive electric energy, the protection unit 380 continuously monitors the voltage at the output end of the first anti-reverse connection unit 450. At S5030, if the voltage at the output end of the first anti-reverse connection unit 450 is less than the sixth voltage threshold Vth6, then at S5040, the protection unit 380 enables the first power supply unit 210 to start receiving power. It should be noted that S5020 and S5030 are continuously executed during the entire working process of the power supply device, and there is no order compared with S5040 to S5120.

[0050] At S5050 , the first control subunit 2401 determines whether the voltage at its first input terminal is greater than a first voltage threshold Vth1 . If the voltage is greater than the first voltage threshold Vth1 , then at S5060 , the first control subunit 2401 enables the second power supply unit 220 to start receiving electrical energy.

[0051] At S5070, the second control subunit 2402 determines whether the voltage at its first input terminal is greater than the second voltage threshold Vth2. If the voltage is greater than the second voltage threshold Vth2, at S5080, the second control subunit 2402 enables the third power supply unit 230 to start receiving electrical energy.

[0052] In addition, when the second power supply unit 220 receives electric energy, the first control subunit 2401 continuously monitors the voltage of its first input terminal. If at S5090, the first control subunit 2401 determines that the voltage is less than the third voltage threshold Vth3, then at S5100, the first control subunit 2401 causes the second power supply unit 220 to stop receiving electric energy.

[0053] In addition, when the third power supply unit 230 receives electric energy, the second control subunit 2402 continuously monitors the voltage of its first input terminal. If at S5110, the second control subunit 2402 determines that the voltage is less than the fourth voltage threshold Vth4, then at S5120, the second control subunit 2402 causes the third power supply unit 230 to stop receiving electric energy.

[0054] Figure 6 The flowchart of the power supply method 600 of the power supply device of the motor protector according to the embodiment of the present disclosure is shown. The motor protector receives electric energy by inducing the alternating current in the power supply line of the motor through the power supply coil and converting the induced alternating current into direct current using a rectifier. The power supply method 600 can be applied to the power supply device of the self-powered motor protector, such as the above Figure 1-Figure 4 The power supply device described. The power supply method 600 includes steps S610-S630. In step S610, the power supply device receives electric energy and supplies power to the tripping device of the motor protector; in step S620, the power supply device receives electric energy and supplies power to the computing and control device of the motor protector; in step S630, the power supply device receives electric energy and supplies power to the reclosing device of the motor protector. The above steps can be performed by any suitable hardware of the power supply device or hardware combined with software. For example, the power supply device may include the above-mentioned first power supply unit, the second power supply unit, and the third power supply unit. Step S610 can be performed by the above-mentioned first power supply unit, that is, in step S610, the first power supply unit receives and stores electric energy and supplies power to the tripping device of the motor protector. For example, step S620 can be performed by the above-mentioned second power supply unit, that is, in step S620, the second power supply unit receives electric energy and supplies power to the computing and control device of the motor protector. For example, step S630 can be performed by the third power supply unit, that is, in step S630, the third power supply unit receives and stores electric energy, and supplies power to the reclosing device of the motor protector. In addition, the power supply device also controls the order in which the first power supply unit, the second power supply unit, and the third power supply unit receive electric energy, so that the first power supply unit first receives electric energy, then the second power supply unit receives electric energy, and finally the third power supply unit receives electric energy, so that the tripping device of the motor protector is first powered, then the calculation and control device of the motor protector is powered, and finally the reclosing device of the motor protector is powered. The above-mentioned timing control can also be performed by any suitable hardware of the power supply device or hardware combined with software, for example, by the above-mentioned control unit included in the power supply device.

[0055] According to the power supply method of the embodiment of the present disclosure, by controlling the order in which the first, second, and third power supply units receive electric energy, the first power supply unit can be given the highest energy storage priority, so that even when the rated current is small, it can be started more quickly (for example, within 1 second) and the ground fault protection function can be realized. In addition, the third power supply unit can receive electric energy and supply power to the reclosing device, so that the automatic reclosing function is also taken into account when the ground fault protection function is realized.

[0056] The hardware computing device described in the present disclosure may be implemented in its entirety or in parts thereof through various suitable hardware means, including but not limited to FPGA, ASIC, SoC, discrete gate or transistor logic, discrete hardware components, or any combination thereof.

[0057] The block diagrams of circuits, devices, apparatuses, equipment, and systems involved in the present disclosure are only illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As will be appreciated by those skilled in the art, these circuits, devices, apparatuses, equipment, and systems may be connected, arranged, or configured in any manner as long as the desired purpose can be achieved.

[0058] Those skilled in the art should understand that the above-mentioned specific embodiments are merely examples and not limitations, and various modifications, combinations, partial combinations and replacements may be made to the embodiments of the present disclosure according to design requirements and other factors. As long as they are within the scope of the attached claims or their equivalents, they belong to the scope of rights to be protected by the present disclosure.

Claims

1. A power supply device for a motor protector, wherein the motor protector receives electrical energy by inducing alternating current in the power supply line of the motor via a power supply coil and converting the induced alternating current into direct current using a rectifying device, and the power supply device comprises: A first power supply unit, which receives and stores the electrical energy and supplies power to the tripping device of the motor protector; A second power supply unit, which receives the electrical energy and supplies power to the calculation and control device of the motor protector; A third power supply unit, which receives and stores the electrical energy and supplies power to the reclosing device of the motor protector; and A control unit, which controls the order in which the first power supply unit, the second power supply unit, and the third power supply unit receive the electrical energy, such that the first power supply unit, the second power supply unit, and the third power supply unit do not receive the electrical energy simultaneously, but rather the first power supply unit receives the electrical energy first, then the second power supply unit receives the electrical energy, and finally the third power supply unit receives the electrical energy.

2. The power supply device according to claim 1, wherein the control unit comprises: A first control sub-unit, which is connected between the rectifying device and the second power supply unit. The first input terminal of the first control sub-unit is connected to the output terminal of the rectifying device, and the output terminal is connected to the second power supply unit. When the voltage at the first input terminal of the first control sub-unit is greater than a first voltage threshold, the first control sub-unit controls the second power supply unit to start receiving the electrical energy; and A second control sub-unit, which is connected between the rectifying device and the third power supply unit. The first input terminal of the second control sub-unit is connected to the output terminal of the rectifying device, and the output terminal is connected to the third power supply unit. When the voltage at the first input terminal of the second control sub-unit is greater than a second voltage threshold, the second control sub-unit controls the third power supply unit to start receiving the electrical energy, wherein the second voltage threshold is greater than the first voltage threshold.

3. The power supply device according to claim 2, wherein when the voltage at the first input terminal of the first control sub-unit is less than a third voltage threshold, the first control sub-unit controls the second power supply unit to stop receiving the electrical energy, and the third voltage threshold is less than or equal to the first voltage threshold; when the voltage at the first input terminal of the second control sub-unit is less than a fourth voltage threshold, the second control sub-unit controls the third power supply unit to stop receiving the electrical energy, and the fourth voltage threshold is less than or equal to the second voltage threshold, and the fourth voltage threshold is greater than the third voltage threshold.

4. The power supply device according to any one of claims 1-3, wherein the first power supply unit comprises a first energy storage sub-unit, which receives the electrical energy to store electrical energy and supplies power to the tripping device of the motor protector using the stored electrical energy.

5. The power supply device according to any one of claims 1-3, wherein The second power supply unit includes a first power supply subunit, which receives the electric energy and supplies power to the calculation and control device of the motor protector with a first output voltage required by the calculation and control device.

6. The power supply device according to any one of claims 1 to 3, wherein The third power supply unit includes a second power supply subunit and a second energy storage subunit, The second power supply subunit receives the electric energy and supplies power to the second energy storage subunit at a second output voltage required by the second energy storage subunit; The second energy storage subunit receives the electric energy provided by the second power supply subunit to store the electric energy, and uses the stored electric energy to supply power to the reclosing device.

7. The power supply device according to claim 6, wherein The third power supply unit further includes a current limiting circuit connected between the second power subunit and the rectifying device, so that a current flowing from the rectifying device into the second power subunit is less than or equal to a first current threshold.

8. The power supply device according to claim 2 or 3, further comprising a first anti-reverse connection unit, a second anti-reverse connection unit and a third anti-reverse connection unit, wherein The input end of the first anti-reverse connection unit is connected to the output end of the rectifier device, and the output end of the first anti-reverse connection unit is respectively connected to the input end of the second anti-reverse connection unit and the input end of the third anti-reverse connection unit; The output end of the second anti-reverse connection unit is connected to the first power supply unit; The output end of the third anti-reverse connection unit is respectively connected to the first input end and the second input end of the first control subunit and the first input end of the second control subunit, and the input end of the third anti-reverse connection unit is connected to the second input end of the second control subunit.

9. The power supply device according to claim 8, further comprising a protection unit, wherein The first input end of the protection unit is connected to the output end of the first anti-reverse connection unit, the second input end of the protection unit is connected to the output end of the rectifier, and the output end of the protection unit is connected to the reference ground. When the voltage of the first input end of the protection unit is greater than a fifth voltage threshold, the protection unit enables the first power supply unit, the second power supply unit, and the third power supply unit to stop receiving the electric energy; and When the voltage at the first input terminal of the protection unit is less than a sixth voltage threshold, the protection unit enables the first power supply unit to start receiving the electric energy, and the sixth voltage threshold is less than the fifth voltage threshold.

10. The power supply device according to claim 8, wherein The first control subunit includes a first hysteresis voltage comparison circuit and a first electronic switch, the first electronic switch is connected between the output end of the third anti-reverse connection unit and the second power supply unit, the input end of the first hysteresis voltage comparison circuit is connected to the output end of the third anti-reverse connection unit, and the output end of the first hysteresis voltage comparison circuit is connected to the control end of the first electronic switch; The second control subunit includes a second hysteresis voltage comparison circuit and a second electronic switch, wherein the second electronic switch is connected between the input end of the third anti-reverse connection unit and the third power supply unit, the input end of the second hysteresis voltage comparison circuit is connected to the output end of the third anti-reverse connection unit, and the output end of the second hysteresis voltage comparison circuit is connected to the control end of the second electronic switch. in, When the voltage at the input end of the first hysteresis voltage comparison circuit is greater than a first voltage threshold, the output end of the first hysteresis voltage comparison circuit outputs a control signal to close the first electronic switch, so that the second power supply unit starts to receive the electric energy; When the voltage at the input end of the first hysteresis voltage comparison circuit is less than a third voltage threshold, the output end of the first hysteresis voltage comparison circuit outputs a control signal to disconnect the first electronic switch, so that the second power supply unit stops receiving the electric energy; When the voltage at the input end of the second hysteresis voltage comparison circuit is greater than a second voltage threshold, the output end of the second hysteresis voltage comparison circuit outputs a control signal to close the second electronic switch, so that the third power supply unit starts to receive the electric energy; When the voltage at the input end of the second hysteresis voltage comparison circuit is less than a fourth voltage threshold, the output end of the second hysteresis voltage comparison circuit outputs a control signal to disconnect the second electronic switch, so that the third power supply unit stops receiving the electric energy.

11. The power supply device according to claim 4, wherein The first energy storage subunit is a capacitor.

12. The power supply device according to claim 5, wherein The first power supply subunit is a step-down circuit.

13. The power supply device according to claim 6 or 7, wherein The second power supply subunit is a boost circuit, and the second energy storage subunit is a capacitor.

14. The power supply device according to claim 8, wherein The first anti-reverse connection unit, the second anti-reverse connection unit, and the third anti-reverse connection unit are diodes respectively, the input ends of the first anti-reverse connection unit, the second anti-reverse connection unit, and the third anti-reverse connection unit are anodes of the diodes respectively, and the output ends of the first anti-reverse connection unit, the second anti-reverse connection unit, and the third anti-reverse connection unit are cathodes of the diodes respectively.

15. The power supply device according to claim 9, wherein The protection unit includes a third hysteresis voltage comparison circuit and a third electronic switch, wherein the third electronic switch is connected between the output end of the rectifier device and the reference ground, the input end of the third hysteresis voltage comparison circuit is connected to the output end of the first anti-reverse connection unit, and the output end of the third hysteresis voltage comparison circuit is connected to the control end of the third electronic switch. in, When the voltage at the input end of the third hysteresis voltage comparison circuit is greater than the fifth voltage threshold, the output end of the third hysteresis voltage comparison circuit outputs a control signal to close the third electronic switch, so that the first power supply unit, the second power supply unit, and the third power supply unit stop receiving the electric energy. Furthermore, when the voltage at the input end of the third hysteresis voltage comparison circuit is less than a sixth voltage threshold, the output end of the third hysteresis voltage comparison circuit outputs a control signal to disconnect the third electronic switch so that the first power supply unit starts to receive the electrical energy.

16. A power supply method for a power supply device of a motor protector, wherein the motor protector receives electric energy by inducing AC power in a power supply line of a motor via a power supply coil and converting the induced AC power into DC power using a rectifier, wherein the power supply device comprises a first power supply unit, a second power supply unit, a third power supply unit and a control unit, wherein the power supply method include: The first power supply unit receives and stores the electric energy and supplies power to the tripping device of the motor protector; The second power supply unit receives the electric energy and supplies power to the calculation and control device of the motor protector; The electric energy is received and stored by a third power supply unit, and is supplied to the reclosing device of the motor protector, wherein The control unit controls the order in which the first power supply unit, the second power supply unit, and the third power supply unit receive the electric energy so that the first power supply unit, the second power supply unit, and the third power supply unit do not receive the electric energy at the same time, but the first power supply unit first receives the electric energy, then the second power supply unit receives the electric energy, and finally the third power supply unit receives the electric energy.

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