Patent ID: 12212131

DETAILED DESCRIPTION

Hereinafter, the disclosure will be described in detail with reference to exemplary embodiments thereof. However, the disclosure is not limited to the embodiments described herein, but may be implemented in many different forms. The described embodiments are only used to make this disclosure thorough and complete, and to fully convey the concepts of this disclosure to those skilled in the art. The features of the described various embodiments may be combined or replaced with each other unless explicitly excluded or should be excluded according to the context.

A self-powered motor protector receives the power via the power supplying coil, so as to supply power for each circuit or device within the motor protector. Specifically, a three-phase alternating current in a power supply line of a motor is induced by a three-phase current transformer (i.e., the power supplying coil) of a motor protector, then the induced alternating current is converted into direct current by a rectifier device of the motor protector, and each circuit or device in the motor protector is powered by the direct current. Accordingly, the power 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, in a case that the load current is the minimum rated current, the output power of the power supplying coil is only 100 mW, and the driving power required by the tripping device within the motor protector is about 600 mW, thus it may not be ensured that tripping can be completed in the event of a ground fault.

An embodiment of the disclosure provides a power supply device for a motor protector, the power supply device is provided with the first power supplying unit, the second power supplying unit and the third power supplying unit to supply power to the tripping device, the calculation and control device, and the reclosing device of the motor protector respectively. The first power supplying unit is associated with the tripping device that implements a ground fault protection function, and can pre-store power for tripping. By controlling the order in which the first, the second and third power supplying units receive power, the first power supplying unit can be given the highest priority for energy storage, so that the ground fault protection function can be started and implemented more quickly (for example, within 1 second) even in a case of small rated current. In addition, according to the embodiment of the disclosure, the third power supplying unit is associated with the reclosing device which implements the automatic reclosing function of the motor protector in a case of the thermal overload, and can pre-store the power for automatic reclosing, so that the automatic reclosing function can also be taken into account while implementing the ground fault protection function.

FIG.1is a schematic circuit module diagram of a self-powered motor protector100according to an embodiment of the disclosure. As shown inFIG.1, the motor protector100includes a power supplying coil110, a rectifier device120, a power supply device130, a tripping device140, a calculation and control device150, and a reclosing device160. The power supplying coil110induces three-phase alternating current in the power supply line of the motor, and then the rectifier device120converts the induced alternating current into direct current. The power supply device130receives the direct current and supplies power to the tripping device140, the calculation and control device150, and the reclosing device160in the motor protector100respectively. The tripping device140is configured to implement the tripping function in a case of fault or overload. The calculation and control device150which may be, for example, a micro-control unit (MCU), and is configured for calculation and control logic processes such as calculating the ground fault current, judging whether a fault occurs, and controlling whether to drive the tripping device140, etc. The reclosing device160is configured to implement the automatic reclosing function after a predetermined time elapses from tripping due to thermal overload.

FIG.2is a schematic circuit module diagram of a power supply device200for a motor protector according to an embodiment of the disclosure. The power supply device200may include a first power supplying unit210configured to receive and store the power and supply power to the tripping device140of the motor protector. As mentioned above, in a case that the load current is the minimum rated current, the output power of the power supplying coil may not meet the driving power required by the tripping device in the motor protector, so that it can't be ensured that tripping is completed in the event of a ground fault. Accordingly, it is required to pre-store power for tripping. In an embodiment, as shown inFIG.2, the first power supplying unit210may include a first energy storing subunit2101configured to receive the power to store the power, and supply power to the tripping device140of the motor protector by utilizing the stored power, so that to ensure that there is enough driving power to drive the tripping device140when a ground fault occurs.

The power supply device200may further include a second power supplying unit220configured to receive power and supply power to the calculation and control device150of the motor protector. As mentioned above, the calculation and control device150may be a micro control unit (MCU), and the power supply voltage for MCU is generally 3.3V. Accordingly, it is required to decrease the input voltage to about 3.3V for providing to MCU. In an embodiment, as shown inFIG.2, the second power supplying unit220may include a first power supply subunit2201configured to receive the power and supply power to the calculation and control device150at a first output voltage (for example, 3.3V) required by the calculation and control device150. The first output voltage may be set according to the practical configuration of the circuit.

As described above, the motor protector according to the disclosure can also take the automatic reclosing function into account while implementing the ground fault protection function. Accordingly, the power supply device200may further include a third power supplying unit230configured to receive and store the power, and supply power to the reclosing device160of the motor protector. After the tripping device140is tripped, the motor stops running, the power supplying coil110can't induce current, so that there is no power supplying current for the motor protector. Accordingly, it is required to pre-store power for automatic reclosing. In an embodiment, as shown inFIG.2, the third power supplying unit230may include a second energy storing subunit2302configured to store the power and supply power to the reclosing device160utilizing the stored power. In addition, a relatively high input voltage is required by the second energy storing subunit2302because a relatively high driving power is required by the reclosing device160. In this case, the third power supplying unit230may further include a second power supply subunit2301configured to receive the power and supply power to the second energy storing subunit2302at a second output voltage (for example, 30V or higher) required by the second energy storing subunit2302, the second output voltage may be set according to the practical configuration of the circuit. In another embodiment, in order to avoid excessive instantaneous current flowing into the second power supply subunit2301, as shown inFIG.2, the third power supplying unit230may further include a current limiting circuit2303. The current limiting circuit2303is connected between the second power supply subunit2301and the rectifier device120(for example, connected to the rectifier device120via the control unit240) to make the current flowing from the rectifier device120into the second power supply subunit2301be less than or equal to the first current threshold Cth1. The first current threshold Cth1may be set according to the practical configuration of the circuit.

According to the embodiment of the disclosure, the first power supplying unit210, the second power supplying unit220and the third power supplying unit230are provided in the power supply device200to supply power to the tripping device140, the calculation and control device150, and the reclosing device160of the motor protector respectively. However, as described above, a trip time is also required (for example, within 1 second), for example, in the standard IEC 60947-1. If the time for supplying power to the tripping device140, the calculation and control device150, and the reclosing device160is not limited, for example, if they are supplied with power at the same time, the time for the first energy storing subunit2101to store the power will be affected, so that the time for starting and implementing the ground fault protection will also be affected.

In order to implement the ground fault protection function more quickly, the power supply device according to the embodiment of the disclosure also controls the timing of receiving power by the first power supplying unit210, the second power supplying unit220, and the third power supplying unit230.

As mentioned above, the ground fault protection function requires short trip time, accordingly, from the perspective of power supplying, the first power supplying unit210should be given the highest priority so that it can receive and store full power as soon as possible. Storing full power means that even if the power supplying coil does not provide current at all, the stored power is enough to drive the tripping device.

Secondly, only when the calculation and control device150is in operation, operations such as calculating the ground fault current, judging whether a fault occurs and controlling whether to drive the tripping device140can be implemented, accordingly, from the perspective of power supplying, the second power supplying unit220should be given a priority second only to the first power supplying unit210.

Finally, the automatic reclosing function is allowed to be performed only in a case that tripping is caused by thermal overload, while the automatic reclosing function is not required to be performed in a case that only a ground fault occurs. For overload protection, in a case that the overload current is small (for example, 1.2 times of the rated current), the cold trip time approximately ranges from 30 minutes to 2 hours, and the hot trip time is also greater than 1 minute, accordingly the delay in supplying power to the third power supplying unit230is allowed. However, in a case that the overload current is large (for example, 7.2 times of the rated current), the power supplying capability of the power supplying coil is strong to enable the first power supplying unit210to quickly complete power storage and supply power to the second power supplying unit220, and to enable the third power supplying unit230to begin to receive the power. In addition, before performing the automatic reclosing function, for example, the MCU needs to judge various conditions such as the magnitude of real-time current, current heat capacity value and the time for power-on, etc., and the automatic reclosing can be performed only when all the conditions are met. Accordingly, from the perspective of power supplying, the priority of the third power supplying unit230is lowest.

Accordingly, as shown inFIG.2, the power supply device200may further include the control unit240configured to control the order in which the first power supplying unit210, the second power supplying unit220and the third power supplying unit230receive the power, so that the power is firstly received by the first power supplying unit, and then received by the second power supplying unit and finally received by the third power supplying unit, thus the ground fault protection function can be started and implemented more quickly even when the rated current is small, and in the meanwhile, the automatic reclosing function is also taken into account.

In an embodiment, as shown inFIG.2, the above mentioned timing control is implemented by providing a first control subunit2401and a second control subunit2402in the control unit. The first control subunit2401is connected between the rectifier device120and the second power supplying unit220. Specifically, the first input terminal of the first control subunit2401is connected with the output terminal of the rectifier device120, and the output terminal of the first control subunit2401is connected with the second power supplying unit220. The first control subunit2401controls the second power supplying unit220to begin to receive the power only when the voltage at the first input terminal of the first control subunit2401is higher than a first voltage threshold Vth1. When the voltage at the first input terminal of the first control subunit2401is higher than the first voltage threshold Vth1, it indicates that the first power supplying unit210has completed the storage of power, so that the second power supplying unit220may begin to receive the power, thereby ensuring that the first power supplying unit210receives the power before the second power supplying unit220.

The second control subunit2402is connected between the rectifier device120and the third power supplying unit230. Specifically, the first input terminal of the second control subunit2402is connected with the output terminal of the rectifier device120, and the output terminal of the second control subunit2402is connected with the third power supplying unit230. The second control subunit2402controls the third power supplying unit230to begin to receive the power only when the voltage of the first input terminal of the second control subunit2402is higher than a second voltage threshold Vth2. The second voltage threshold Vth2may be higher than the first voltage threshold Vth1to ensure that the second power supplying unit220receives the power before the third power supplying unit230.

In a case that the second power supplying unit220and/or the third power supplying unit230have/has begun to receive the power, the power supplying capability of the power supplying coil may decrease for some reason, so that the normal operation of the first power supplying unit may be affected. For example, when the power supplying capability of the power supplying coil decreases and it is insufficient to supply power to the second power supplying unit220and/or the third power supplying unit230, the second power supplying unit220and/or the third power supplying unit230may draw the power from the power stored in the first power supplying unit210, so that the normal operation of the first power supplying unit210may be affected. In order to avoid this situation, the control unit240may also limit the timing when the second power supplying unit220and the third power supplying unit230stop receiving the power. In an embodiment, when the voltage of the first input terminal of the first control subunit2401is lower than a third voltage threshold Vth3, the first control subunit2401controls the second power supplying unit220to stop receiving power. A third voltage threshold Vth3may be lower than or equal to the first voltage threshold Vth1, that is, the voltage thresholds for controlling the second power supplying unit220to begin to receive and to stop receiving the power may be the same or different. Compared with the case where the third voltage threshold Vth3is equal to the first voltage threshold Vth1, the time for controlling the second power supplying unit220to receive the power can be extended in a case that the third voltage threshold Vth3is lower than the first voltage threshold Vth1. In another embodiment, when the voltage of the first input terminal of the second control subunit2402is lower than a fourth voltage threshold Vth4, the second control subunit2402controls the third power supplying unit230to stop receiving power. The fourth voltage threshold Vth4may be lower than or equal to the second voltage threshold Vth2, that is, the voltage thresholds for controlling the third power supplying unit230to begin to receive and to stop receiving the power may be the same or different. Compared with the case where the fourth voltage threshold Vth4is equal to the second voltage threshold Vth2, the time for controlling the third power supplying unit230to receive power can be extended in a case that the fourth voltage threshold Vth4is lower than the second voltage threshold Vth2. The fourth voltage threshold Vth4may be higher than the third voltage threshold Vth3, so that when the power supplying capability of the power supplying coil is insufficient, the third power supplying unit230is first made to stop receiving power, and when the power supplying capability of the power supplying coil continues to deteriorate, the second power supplying unit220is made to stop receiving power.

In another embodiment, in order to ensure that the first and third power supplying units can store the power separately and reduce the mutual influence among the first to third power supplying units decrease (i.e., the anti-reverse connection function), an anti-reverse connection unit may also be added, as shown inFIG.3.FIG.3is a schematic circuit module diagram of a power supply device300according to another embodiment of the disclosure, the difference betweenFIG.3andFIG.2is that the power supply device300inFIG.3further includes a first anti-reverse connection unit350, a second anti-reverse connection unit360and a third anti-reverse connection unit370. The input terminal of the first anti-reverse connection unit350is connected with the output terminal of the rectifier device120, and the output terminal of the first anti-reverse connection unit350is connected with the input terminal of the second anti-reverse connection unit360and the input terminal of the third anti-reverse connection unit370respectively, for providing anti-reverse connection for the whole power supply device. The output terminal of the second anti-reverse connection unit360is connected with the first power supplying unit210for providing further anti-reverse connection for the first power supplying unit210. The input terminal and output terminal of the third anti-reverse connection unit370are connected with the control unit240respectively, specifically, the output terminal of the third anti-reverse connection unit370are connected with the first input terminal and the second input terminal of the first control subunit2401respectively, thus providing further anti-reverse connection for the subsequent second power supplying unit220. In addition, in an embodiment, an additional anti-reverse connection unit may be provided in the current limiting circuit2303included in the third power supplying unit230to provide further anti-reverse connection for the third power supplying unit230. In yet another embodiment, the output terminal of the third anti-reverse connection unit370may also be connected with the first input terminal and the second input terminal of the second control subunit2402respectively, so as to provide further anti-reverse connection for the subsequent third power supplying unit230. In yet another embodiment, the additional anti-reverse connection unit may be provided in each of the first to third power supplying units to provide further anti-reverse connection. In addition, as shown inFIG.3, in a case that respective anti-reverse connection units are provided, the first input terminal of the second control subunit2402can be connected with the output terminal of the third anti-reverse connection unit370, and the second input terminal of the second control subunit2402can be connected with the input terminal of the third anti-reverse connection unit370, so as to control the reception of power by the third power supplying unit230.

In yet another embodiment, in order to avoid the elements in the power supply device are damaged due to the excessive current and voltage flowing into the power supply device from the power supplying coil, a protection unit380may also be added, as shown inFIG.3. The first input terminal of the protection unit380is connected with the output terminal of the first anti-reverse connection unit350, the second input terminal is connected with the output terminal of the rectifier device120, and the output of the protection unit380is connected with the reference ground. When the voltage at the first input terminal of the protection unit380is higher than a fifth voltage threshold value Vth5due to the excessive current and voltage flowing from the power supplying coil into the power supply device, the protection unit380can discharge the excessive current and voltage to the reference ground, so that the first power supplying unit210, the second power supplying unit220and the third power supplying unit230stop receiving the power. In a case that the first power supplying unit210, the second power supplying unit220and the third power supplying unit230stop receiving the power, when the voltage at the first input terminal of the protection unit380is lower than a sixth voltage threshold Vth6due to the release of power stored in the first and third power supplying units, the first power supplying unit210, the second power supplying unit220and the third power supplying unit230can resume receiving power. That is, when the voltage of the first input terminal of the protection unit380is lower than the sixth voltage threshold Vth6, the protection unit380can enable the first power supplying unit210to begin to receive power, so that the second power supplying unit220and the third power supplying unit230can also receive power subsequently based on the control of the control unit240. The sixth voltage threshold Vth6may be lower than the fifth voltage threshold Vth5to ensure that elements in the power supply device will not be damaged.

According to the above embodiments of the disclosure, the first, the second and the third power supplying units are provided in the power supply device for the self-powered motor protector 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, the second and the third power supplying units receive power, the first power supplying unit can be given the highest priority for energy storage, so that the ground fault protection function can be started and implemented more quickly (for example, within 1 second) even in a case of small rated current. In addition, the third power supplying unit can pre-store the power for automatic reclosing, so that the automatic reclosing function can be taken into account while implementing the ground fault protection function.

The respective units of the power supply device of the disclosure can be implemented by various specific circuits.FIG.4shows a schematic circuit diagram of a power supply device400according to an embodiment of the disclosure. It should be noted that the specific structures of respective units inFIG.4can be individually applied or replaced by other suitable structures.

As shown inFIG.4, the first anti-reverse connection unit450, the second anti-reverse connection unit460and the third anti-reverse connection unit470can be a first diode D1, a second diode D2and a third diode D3respectively. The anode of the first diode D1is connected with the rectifier device120, and the cathode of the first diode D1is connected with the anodes of the second diode D2and the third diode D3respectively, for providing anti-reverse connection for the whole power supply device. The cathode of the second diode D2is connected with the first power supplying unit410, for providing further anti-reverse connection for the first power supplying unit410. The cathode of the third diode D3is connected with the first and second input terminals of the first control subunit4401respectively, so as to provide further anti-reverse connection for the subsequent second power supplying unit420. The cathode of the third diode D3is also connected with the first input of the second control subunit4402, and the anode of the third diode D3is also connected with the second input of the second control subunit4402.

The first energy storing subunit included in the first power supplying unit410may be a capacitor C1, which is connected between the second anti-reverse connection unit460and the tripping device140and configured to receive and store power and utilize the stored power to supply the power to the tripping device140. The capacitance value of the capacitor C1may be set according to the practical configuration of the circuit. It should be noted that although the first energy storing subunit is shown as a capacitor C1inFIG.4, the first energy storing subunit is not limited to a capacitor, and in an embodiment, the first energy storing subunit may also be an energy storage battery.

The first power supply subunit included in the second power supplying unit420may be a buck circuit BUCK, which is connected between the first control subunit4401and the calculation and controlling device150and configured to receive the power and supply power to the calculation and controlling device150at the first output voltage required by the calculation and controlling device150. The first output voltage may be set according to the practical configuration of the circuit.

The current limiting circuit included in the third power supplying unit430can be a common current limiter CL, which is connected between the second control subunit4402and the second power supply subunit, so that the current flowing from the rectifier device120into the second power supply subunit is less than or equal to a first current threshold Cth1. The first current threshold Cth1may be set according to the practical configuration of the circuit. As described above, in an embodiment, the current limiting circuit included in the third power supplying unit430may also be a combination of the current limiter CL and the anti-reverse connection unit.

The second power supply subunit included in the third power supplying unit430may be a boost circuit BOOST, which is connected between the current limiting circuit and the second energy storing subunit and configured to receive the power and supply power to the second energy storing subunit at a second output voltage required by the second energy storing subunit, the second output voltage may be set according to the practical configuration of the circuit.

The second energy storing subunit included in the third power supplying unit430may be a capacitor C2, which is connected between the second power supply subunit and the reclosing device160and configured to receive and store the power and utilize the stored power to supply power to the reclosing device160. The capacitance value of the capacitor C2may be set according to the practical configuration of the circuit. It should be noted that although the second energy storing subunit is shown as a capacitor C2inFIG.4, the second energy storing subunit is not limited to a capacitor, in an embodiment, the second energy storing subunit may also be an energy storage battery.

The first control subunit4401may include a first hysteresis voltage comparing circuit VC1and a first electronic switch SW1. The first electronic switch SW1is connected between the output terminal of the third anti-reverse connection unit470and the second power supplying unit420, the input terminal of the first hysteresis voltage comparing circuit VC1is connected with the output terminal of the third anti-reverse connection unit470, and the output terminal of the first hysteresis voltage comparing circuit VC1is connected with the control terminal of the first electronic switch SW1. The input terminal of the first hysteresis voltage comparing circuit VC1corresponds to the first input terminal of the first control subunit4401, the terminal of the first electronic switch SW1which is connected with the output terminal of the third anti-reverse connection unit470corresponds to the second input terminal of the first control subunit4401, and the terminal of the first electronic switch SW1which is connected with the second power supplying unit420corresponds to the output terminal of the first control subunit4401.

The hysteresis voltage comparing circuit is a special voltage comparing circuit, and its transmission characteristics have the shape of “hysteresis” curve. The hysteresis voltage comparing circuit has two unequal thresholds. For example, when the input voltage gradually increases to the first threshold, the hysteresis voltage comparing circuit may output a high level, while when the input voltage gradually decreases to the second threshold, the hysteresis voltage comparing circuit can output a low level. In an embodiment of the disclosure, when the voltage at the input terminal of the first hysteresis voltage comparing circuit VC1is higher than the first voltage threshold Vth1, the output terminal of the first hysteresis voltage comparing circuit VC1outputs a control signal to close the first electronic switch SW1, so that the second power supplying unit420begins to receive the power; and when the voltage at the input terminal of the first hysteresis voltage comparing circuit VC1is lower than the third voltage threshold Vth3, the output terminal of the first hysteresis voltage comparing circuit outputs a control signal to open the first electronic switch SW1, so that the second power supplying unit420stops receiving the power. The first voltage threshold Vth1is higher than the third voltage threshold Vth3.

There are types of electronic switches for common usage, such as IGBT, GTO (Gate Turn-off Thyristor), transistor, MOS (metal oxide semiconductor) transistor, etc., these electronic switches can be selected by those skilled in the art according to practical application scenarios. For example, in the embodiment of the disclosure, if the first electronic switch SW1is a MOS transistor, then its gate is the control terminal and is connected with the output terminal of the first hysteresis voltage comparing circuit VC1; its source and drain are connected with the second power supplying unit420(the input terminal of the buck circuit BUCK) and the output terminal of the third anti-reverse connection unit470(the third diode D3) respectively.

The second control subunit4402includes a second hysteresis voltage comparing circuit VC2and a second electronic switch SW2, the second electronic switch SW2is connected between the input terminal of the third anti-reverse connection unit470and the third power supplying unit430, the input terminal of the second hysteresis voltage comparing circuit VC2is connected with the output terminal of the third anti-reverse connection unit470, the output terminal of the second hysteresis voltage comparing circuit VC2is connected with the control terminal of the second electronic switch SW2. The input terminal of the second hysteresis voltage comparing circuit VC2corresponds to the first input terminal of the second control subunit4402, the terminal of the second electronic switch SW2connected with the input terminal of the third anti-reverse connection unit470corresponds to the second input terminal of the second control subunit4402, and the terminal of the second electronic switch SW2connected with the third power supplying unit430corresponds to the output terminal of the second control subunit4402. In an embodiment of the disclosure, when the voltage at the input terminal of the second hysteresis voltage comparing circuit VC2is higher than the second voltage threshold Vth2, the output terminal of the second hysteresis voltage comparing circuit VC2outputs a control signal to close the second electronic switch SW2, so that the third power supplying unit430begins to receive the power; when the voltage at the input terminal of the second hysteresis voltage comparing circuit VC2is lower than the fourth voltage threshold Vth4, the output terminal of the second hysteresis voltage comparing circuit VC2outputs a control signal to open the second electronic switch SW2, so that the third power supplying unit430stops receiving power. The second voltage threshold Vth2is higher than fourth voltage threshold Vth4.

In an embodiment of the disclosure, if the second electronic switch SW2is a MOS transistor, then its gate is the control terminal and is connected with the output terminal of the second hysteresis voltage comparing circuit VC2; its source and drain are connected with the third power supplying unit430(input terminal of the current limiter CL) and the input terminal of the third anti-reverse connection unit470(the third diode D3) respectively.

The protection unit480may include a third hysteresis voltage comparing circuit VC3and a third electronic switch SW3, the third electronic switch SW3is connected between the output terminal of the rectifier device120and the reference ground, the input terminal of the third hysteresis voltage comparing circuit VC3is connected with the output terminal of the first anti-reverse connection unit450, and the output terminal of the third hysteresis voltage comparing circuit VC3is connected with the control terminal of the third electronic switch SW3. The input terminal of the third hysteresis voltage comparing circuit VC3corresponds to the first input terminal of the protection unit480, the terminal of the third electronic switch SW3connected with the output terminal of the rectifier device120corresponds to the second input terminal of the protection unit480, and the terminal of the third electronic switch SW3connected with the reference ground corresponds to the output terminal of the protection unit480.

In an embodiment of the disclosure, when the voltage at the input terminal of the third hysteresis voltage comparing circuit VC3is higher than the fifth voltage threshold Vth5, the output terminal of the third hysteresis voltage comparing circuit VC3outputs a control signal to close the third electronic switch SW3to discharge excessive current and voltage to the reference ground and stop the first power supplying unit410, the second power supplying unit420and the third power supplying unit430from receiving the power. When the voltage at the input terminal of the third hysteresis voltage comparing circuit VC3is lower than the sixth voltage threshold Vth6, the output terminal of the third hysteresis voltage comparing circuit VC3outputs a control signal to open the third electronic switch SW3to enable the first power supplying unit410to begin to receive the power, so that the second power supplying unit420and the third power supplying unit430can also subsequently receive power based on the control of the control unit440. The fifth voltage threshold Vth5is higher than the sixth voltage threshold Vth6.

In the embodiment of the disclosure, if the third electronic switch SW3is a MOS transistor, then its gate is the control terminal and is connected with the output terminal of the third hysteresis voltage comparing circuit VC3; its source and drain are connected with the reference ground and the output of the rectifier device120respectively.

FIG.5shows an operation flowchart of the power supply device according to an embodiment of the disclosure. The flowchart ofFIG.5will be briefly explained with reference to the structure of the power supply device inFIG.4. At S5010, the motor starts and power begins to be input into the power supply device. At S5020, the protection unit380of the power supply device continuously determines whether the voltage of the output terminal of the first anti-reverse connection unit450is higher than the fifth voltage threshold Vth5. If it is determined that the voltage is not higher than the fifth voltage threshold Vth5, the first power supplying unit210begins to receive power at S5040; otherwise, if it is determined that the voltage is higher than the fifth voltage threshold Vth5, the protection unit380prevents the first power supplying unit210, the second power supplying unit220and the third power supplying unit230from receiving the power, so that the damage to the power supply device due to excessive current and voltage may be avoided. In addition, if the first power supplying unit210, the second power supplying unit220and the third power supplying unit230do not receive the power, the protection unit380continuously monitors the voltage at the output terminal of first anti-reverse connection unit450. At S5030, if the voltage of the output terminal of the first anti-reverse connection unit450is lower than the sixth voltage threshold Vth6, the protection unit380enables the first power supplying unit210to begin to receive the power at S5040. It should be noted that S5020and S5030are continuously implemented during the whole operation process of the power supply device, and they are not before or after S5040˜S5120.

At S5050, the first control subunit2401determines whether the voltage at its first input terminal is higher than the first voltage threshold Vth1, and if the voltage is higher than the first voltage threshold Vth1, the first control subunit2401enables the second power supplying unit220to begin to receive the power at S5060.

At S5070, the second control subunit2402determines whether the voltage at its first input terminal is higher than the second voltage threshold Vth2, and if the voltage is higher than the second voltage threshold Vth2, the second control subunit2402enables the third power supplying unit230to begin to receive the power at S5080.

In addition, in a case that the second power supplying unit220receives the power, the first control subunit2401continuously monitors the voltage of its first input terminal, if the first control subunit2401determines that the voltage is lower than the third voltage threshold Vth3at S5090, the first control subunit2401stops the second power supplying unit220from receiving the power at S5100.

In addition, in a case that the third power supplying unit230receives the power, the second control subunit2402continuously monitors the voltage at its first input terminal, if the second control subunit2402determines that the voltage is lower than the fourth voltage threshold Vth4at S5110, the second control subunit2402stops the third power supplying unit230from receiving power at S5120.

FIG.6shows a flowchart of a power supplying method600of a power supply device for a motor protector according to an embodiment of the disclosure. The motor protector receives power by inducing alternating current in a power supply line of a motor via the power supplying coil and converting the induced alternating current into direct current utilizing the rectifier device. The power supplying method600can be applied to a power supply device for a self-powered motor protector, for example, the power supply device described inFIGS.1-4above. The power supplying method600includes steps S610-S630. At step S610, the power supply device receives the power and supplies power to the tripping device of the motor protector. At step S620, the power supply device receives the power and supplies power to the calculation and control device of the motor protector. At step S630, the power supply device receives the power and supplies power to the reclosing device of the motor protector. The above mentioned steps can be performed by any suitable hardware or hardware combined with software of the power supply device. For example, the power supply device may include the above mentioned first power supplying unit, the second power supplying unit and the third power supplying unit. Step S610may be performed by the first power supplying unit, that is, at step S610, the first power supplying unit receives and stores the power and supplies power to the tripping device of the motor protector. For example, step S620can be performed by the above mentioned second power supplying unit, that is, at step S620, the second power supplying unit receives the power and supplies power to the calculation and control device of the motor protector. For example, step S630may be performed by the above mentioned third power supplying unit, that is, at step S630, the third power supplying unit receives and stores the power 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 supplying unit, the second power supplying unit and the third power supplying unit receive the power, so that the power is firstly received by the first power supplying unit, then received by the second power supplying unit and finally received by the third power supplying unit, in this way, the power is supplied to the tripping device of the motor protector firstly, and then to the calculation and control device of the motor protector and finally to the reclosing device of the motor protector. The above mentioned timing control can also be performed by any suitable hardware or hardware combined with software of the power supply device, for example, by the above mentioned control unit included in the power supply device.

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

The whole hardware computing device or its components described in this disclosure can be implemented by various suitable hardware means, including but not limited to FPGA, ASIC, SoC, discrete gate or transistor logic, discrete hardware components, or any combination thereof.

The block diagrams of circuits, devices, apparatus, equipment and systems referred to in the disclosure are only taken as illustrative examples, and are not intended to require or imply that they must be connected, arranged and configured in the manner shown in the block diagrams. As will be recognized by those skilled in the art, these circuits, devices, apparatus, equipment and systems can be connected, arranged and configured in any manner as long as the desired purpose can be achieved.

It should be understood by those skilled in the art that the above specific embodiments are only examples and not limitations, and various modifications, combinations, partial combinations and substitutions can be made to the embodiments of this disclosure according to design requirements and other factors, as long as they are within the scope of the appended claims or their equivalents, that is, within the scope of the claims to be protected by this disclosure.