CN113156333A - Alternating current load detection circuit and detection method thereof, and household appliance - Google Patents
Alternating current load detection circuit and detection method thereof, and household appliance Download PDFInfo
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- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/52—Testing for short-circuits, leakage current or ground faults
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
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Abstract
When the alternating current load does not break down, so that the alternating current load detection circuit normally operates, when an external alternating current power supply is in a positive half period, the alternating current power supply flows into the alternating current load through a live wire, then flows into a first end of a switching device through the alternating current load, and flows back to a zero line through a second end of the switching device, so that the switching device outputs a first level signal to a controller. When the external alternating current power supply works in a negative half cycle, the alternating current power supply flows into the freewheeling diode through the zero line, then flows into the alternating current load through the freewheeling diode and flows back to the live wire, and at the moment, the switching device has no power supply input and outputs another level signal to the controller. The controller finally judges according to the level signal received in real time, namely the information whether the alternating current load has a fault can be directly obtained, and the fault detection of the alternating current load is realized.
Description
Technical Field
The present disclosure relates to the field of fault diagnosis technologies, and in particular, to an ac load detection circuit, a detection method thereof, and a home appliance.
Background
The ac load is a device that converts ac power into other forms of energy in an ac circuit to operate. With the rapid development of science and technology, alternating current loads are more and more widely used in daily life of people, for example, a heating tube in an electric water heater commonly used in daily life, a shaded pole motor commonly used in some household appliances and the like bring great convenience to the daily life of people.
However, during the use of these ac loads, short-circuit or open-circuit faults may occur due to improper use or aging of the devices, so that the household electrical appliance may not operate normally. In the using process, a user cannot know the working state of the alternating current load, so that the fault judgment of the alternating current load is difficult to realize.
Disclosure of Invention
In view of the above, it is necessary to provide an ac load detection circuit, a detection method thereof, and a home appliance, in order to solve the problem that it is difficult to determine a failure of an ac load during use.
An alternating current load detection circuit comprising: an alternating current load; the first end of the alternating current load is connected with the cathode of the freewheeling diode, the second end of the alternating current load is connected with the live wire of an external alternating current power supply, and the anode of the freewheeling diode is connected with the zero line of the external alternating current power supply; a first end of the switch device is connected with a cathode of the freewheeling diode, a second end of the switch device is connected with an anode of the freewheeling diode, a third end of the switch device is connected with a power supply, and a grounding end of the switch device is grounded; a first end of the controller is connected with a second end of the alternating current load, a second end of the controller is connected with a zero line of the external alternating current power supply, a third end of the controller is connected with the power supply, a fourth end of the controller is connected with a fourth end of the switching device, and a grounding end of the controller is grounded; the switching device is used for outputting a corresponding level signal to the controller according to the power supply half cycle where the external alternating current power supply is located, and the controller is used for judging whether the alternating current load has a fault according to the level signal.
In one embodiment, the ac load detection circuit further comprises a fuse, and the second terminal of the ac load is connected to the line of the external ac power source through the fuse.
In one embodiment, the switching device includes an optical coupler and a switching device, a first end of a light emitter of the optical coupler serves as a first end of the switching device, a second end of the light emitter of the optical coupler serves as a second end of the switching device, a first end of a light receiver of the optical coupler is connected to the first end of the switching device, a common end of the first end of the light receiver of the optical coupler serves as a third end of the switching device, a second end of the light receiver of the optical coupler is connected to the second end of the switching device and the third end of the switching device, the third end of the switching device serves as a ground terminal of the switching device, and a first end of the switching device serves as a fourth end of the switching device.
In one embodiment, the switching device further includes a first dc current limiting resistor and a second dc current limiting resistor, a second end of the light receiver of the optical coupler is connected to a first end of the first dc current limiting resistor and a third end of the switching device, a second end of the first dc current limiting resistor is connected to a second end of the switching device, a first end of the switching device is connected to a first end of the second dc current limiting resistor and the power supply, and a second end of the second dc current limiting resistor is connected to a fourth end of the controller.
In one embodiment, the switch apparatus further includes a bias resistor and a pull-up resistor, a first end of the bias resistor is connected to the second end of the light receiver of the optical coupler device and the first end of the first dc current limiting resistor, a second end of the bias resistor is connected to the third end of the switch device, a first end of the pull-up resistor is connected to the first end of the second dc current limiting resistor and the first end of the switch device, a second end of the pull-up resistor is connected to the first end of the light receiver of the optical coupler device, and a common end of the pull-up resistor is connected to the power supply.
In one embodiment, the ac load detection circuit further includes an ac current limiting resistor, a first end of the ac current limiting resistor is connected to the first end of the ac load and the cathode of the freewheeling diode, and a second end of the ac current limiting resistor is connected to the anode of the freewheeling diode.
In one embodiment, the ac load detection circuit further comprises an information prompting device, and the information prompting device is connected to the controller.
A detection method of an alternating current load detection circuit, the alternating current load detection circuit being as described above, the detection method comprising: acquiring a level signal output by the switching device in real time; judging whether the level signal changes within a preset time length; and outputting fault information of the AC load circuit breaking when the level signal is not changed within the preset time.
In one embodiment, after the step of determining whether the level signal changes within a preset time period, the method further includes: and when the level signal changes within a preset time length, returning to the step of acquiring the level signal output by the switching device in real time.
In one embodiment, the detection method further comprises: analyzing whether the alternating current load has a short-circuit fault or not according to the working state of the household appliance in which the alternating current load is positioned; and when the AC load has a short-circuit fault, outputting fault information of the short circuit of the AC load.
In one embodiment, the step of analyzing whether the ac load has a short-circuit fault according to the operating state of the household appliance in which the ac load is located includes: acquiring working parameters of household electrical appliance where the alternating current load is located; and analyzing whether the household appliance works normally or not according to the working parameters, wherein the normal working of the household appliance represents that the alternating current load does not have the short-circuit fault, and the abnormal working of the household appliance represents that the alternating current load has the short-circuit fault.
The household appliance comprises the alternating current load detection circuit, and the controller is used for carrying out fault detection on the alternating current load according to the detection method.
According to the alternating current load detection circuit, the detection method and the household appliance, when the alternating current load does not break down so that the alternating current load detection circuit normally operates, when an external alternating current power supply is in a positive half period, the alternating current power supply flows into the alternating current load through a live wire, then flows into the first end of the switching device through the alternating current load, and flows back to a zero line through the second end of the switching device, so that the switching device outputs a first level signal to the controller. When the external alternating current power supply works in a negative half cycle, the alternating current power supply flows into the freewheeling diode through the zero line, then flows into the alternating current load through the freewheeling diode and flows back to the live wire, and at the moment, the switching device has no power supply input and outputs another level signal to the controller. The controller finally judges according to the level signal received in real time, namely the information whether the alternating current load has a fault can be directly obtained, and the fault detection of the alternating current load is realized. Through the scheme, the fault detection can be carried out on the alternating current load in real time through the received level signal, and the fault detection can be timely known when the alternating current load breaks down.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments or the conventional technologies of the present application, the drawings used in the descriptions of the embodiments or the conventional technologies will be briefly introduced below, it is obvious that the drawings in the following descriptions are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a schematic diagram of an embodiment of an AC load detection circuit;
FIG. 2 is a schematic diagram of an alternate current load detection circuit according to another embodiment;
FIG. 3 is a schematic diagram of an AC load detection circuit according to yet another embodiment;
FIG. 4 is a schematic diagram of an AC load detection circuit according to yet another embodiment;
FIG. 5 is a schematic diagram illustrating a detection method of the AC load detection circuit according to an embodiment;
FIG. 6 is a schematic flow chart illustrating a method for detecting an AC load detecting circuit according to another embodiment;
FIG. 7 is a schematic flow chart illustrating a method for detecting an AC load detecting circuit according to another embodiment;
fig. 8 is a schematic diagram illustrating a process of detecting a working state of a home appliance according to an embodiment;
Detailed Description
To facilitate an understanding of the present application, the present application will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present application are illustrated in the accompanying drawings. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
Referring to fig. 1, an ac load detection circuit includes: an AC load 10; a freewheeling diode 20, a first end of the alternating current load 10 is connected with a cathode of the freewheeling diode 20, a second end of the alternating current load 10 is connected with a live wire L of an external alternating current power supply, and an anode of the freewheeling diode 20 is connected with a zero line N of the external alternating current power supply; a switching device 30, wherein a first end of the switching device 30 is connected with a cathode of the freewheeling diode 20, a second end of the switching device 30 is connected with an anode of the freewheeling diode 20, a third end of the switching device 30 is connected with a power supply, and a ground end of the switching device 30 is grounded; a controller 40, a first end of the controller 40 is connected to a second end of the ac load 10, a second end of the controller 40 is connected to a zero line N of an external ac power source, a third end of the controller 40 is connected to a power source, a fourth end of the controller 40 is connected to a fourth end of the switching device 30, and a ground end of the controller 40 is grounded; the switching device 30 is configured to output a corresponding level signal to the controller 40 according to a power supply half-cycle in which the external ac power supply is located, and the controller 40 is configured to determine whether the ac load 10 fails according to the level signal.
Specifically, the ac load 10 is a device that operates by ac power supplied from an ac power source and converts ac power into other forms of energy. The particular type of ac load 10 is not exclusive and the type of ac load 10 may vary from household appliance to household appliance, for example, in one embodiment, the ac load 10 may be an ac heating tube, an ac shaded pole motor, an ac halogen lamp, or the like. When the ac power supply supplies power to the ac load 10, in the same cycle, the ac power supply includes both a positive half cycle in which power is supplied through the ac live line L and a negative half cycle in which power is supplied through the ac zero line N. When the ac power supply operates in the positive half cycle, due to the reverse blocking of the freewheeling diode 20, the ac power flowing from the live line L of the ac power supply flows into the second terminal of the ac load 10, flows out of the first terminal of the ac load 10, flows into the first terminal of the switching device 30, and flows back to the neutral line N of the external ac power supply from the second terminal of the switching device 30, so as to supply power to the ac load 10. In this process, the switching device 30 is powered to be in an operating state, and the third terminal of the switching device 30 is conducted to the ground terminal of the switching device 30, so that the switching device 30 outputs the first level signal to the controller 40.
When the alternating current power supply works in a negative half cycle, due to the forward conduction of the freewheeling diode 20, the alternating current energy flowing out of the zero line N of the alternating current power supply flows in from the anode of the freewheeling diode 20, flows out from the cathode of the freewheeling diode 20, flows into the first end of the alternating current load 10, and flows back to the live line L of the external alternating current power supply from the second end of the alternating current load 10, so that the power supply to the alternating current load 10 is realized. In this process, no power flows between the first terminal and the second terminal of the switching device 30, the switching device 30 is in the off state, and the third terminal is not connected to the ground terminal of the switching device 30, so that the switching device 30 outputs the second level signal to the controller 40. Finally, the control only needs to analyze whether the level signal received in the same period is converted between the first level signal and the second level signal, and the detection result of whether the alternating current load 10 has a fault can be obtained.
Referring to fig. 2, in an embodiment, the ac load detection circuit further includes a fuse 50, and the second terminal of the ac load 10 is connected to the live line L of the external ac power source through the fuse 50.
Specifically, the fuse 50(fuse) is also called a current fuse, and mainly plays a role of overload protection, and by arranging the fuse 50 on the live wire L of the ac power supply, the fuse 50 will self-blow to cut off the current when the current abnormally rises to a certain height and heat, thereby protecting the safe operation of the ac load detection circuit.
It should be noted that the specific type of switching device 30 is not exclusive as long as it is capable of outputting different types of level signals to the controller 40 during the positive and negative half cycles of the external ac power source, respectively. For example, in one embodiment, referring to fig. 3 in combination, the switching device 30 includes an optocoupler U1 and a switching device Q, a first end of the light emitter of the optocoupler U1 serves as a first end of the switching device 30, a second end of the light emitter of the optocoupler U1 serves as a second end of the switching device 30, a first end of the light receiver of the optocoupler U1 is connected to the first end of the switching device Q and the common end serves as a third end of the switching device 30, a second end of the light receiver of the optocoupler U1 is connected to the second end of the switching device Q and the third end of the switching device Q, the third end of the switching device Q serves as a ground terminal of the switching device 30, and the first end of the switching device Q serves as a fourth end of the switching device 30.
Specifically, in the present embodiment, the function of the switching device 30 is realized by the matching of the optocoupler device U1 and the switching device Q, when the external ac power source is in the positive half cycle, the ac power flowing out of the live line L of the external ac power source flows into the first end of the light emitter of the optocoupler device U1 through the ac load 10, flows out of the second end of the light emitter of the optocoupler device U1, and finally flows back to the neutral line N of the external ac power source. In the process, since electric energy flows between the first end and the second end of the light emitter of the optical coupler device U1, the light emitter of the optical coupler device U1 will emit a light signal, and the first end of the light receiver of the optical coupler device U1 and the second end of the light receiver will be conducted due to photoelectric conversion. At this time, the power supply flows in from the first end of the light receiver of the optical coupler device U1, flows out from the second end of the light receiver of the optical coupler device U1, and finally flows to the second end of the switching device Q, so that the switching device Q is controlled to be in a conducting state. Further, when the switching device Q is turned on, the power of the first terminal of the switching device Q will flow to the third terminal of the switching device Q, and finally flow to the ground to form a closed loop. At this time, since the third terminal of the switching device Q is grounded, the power flowing into the controller 40 from the first terminal of the switching device Q is pulled low, and the switching device Q outputs a low-level signal to the controller 40.
When the ac load 10 operates in the negative half cycle, the ac power flows into the freewheeling diode 20 from the neutral line N, and directly flows into the ac load 10 through the freewheeling diode 20 to supply power to the ac load 10, and finally flows back to the live line L of the external ac power supply. At this time, since the ac power does not flow into the light emitter of the optocoupler device U1, the entire optocoupler device U1 will be in the off state, and the second end of the corresponding switching device Q is at the low level, so that the switching device Q is also in the off state. Since the first terminal of the switching device Q is directly connected to the power supply, the high signal is received at the fourth terminal of the controller 40 under the pull-up action of the power supply.
In the scheme of this embodiment, the fault detection of the ac load 10 is realized by using the isolated optocoupler U1 and the switching device Q, and the ac part and the dc part can be safely isolated, so that the optocoupler is suitable for most products and ensures the safety of users. The specific types of the optocoupler device U1 and the switching device Q may be selected in combination with the actual ac load 10.
It can be understood that the specific type of the switching device Q is not exclusive, and any switching device may be used as long as the switching device Q can enter a conducting state when the optocoupler device U1 is turned on, that is, the switching device Q in the conducting state under the control of a high-level signal, and specifically, the switching device Q may be a transistor or a field effect transistor that is turned on at a high level.
Referring to fig. 4, in an embodiment, the ac load detection circuit further includes an ac current limiting resistor R1, a first terminal of the ac current limiting resistor R1 is connected to the first terminal of the ac load 10 and the cathode of the freewheeling diode 20, and a second terminal of the ac current limiting resistor R1 is connected to the anode of the freewheeling diode 20.
Specifically, in this embodiment, an ac current limiting resistor R1 is further connected in parallel to two ends of the freewheeling diode 20, and the current limiting function of the resistor realizes protection of the ac side of the ac load detection circuit, thereby effectively improving the operational reliability of the ac load detection circuit.
Referring to fig. 4, in an embodiment, the switch device 30 further includes a first dc current limiting resistor R2 and a second dc current limiting resistor R3, a second end of the light receiver of the optocoupler U1 is connected to a first end of the first dc current limiting resistor R2 and a third end of the switching device Q, a second end of the first dc current limiting resistor R2 is connected to a second end of the switching device Q, a first end of the switching device Q is connected to a first end of the second dc current limiting resistor R3 and a power source, and a second end of the second dc current limiting resistor R3 is connected to a fourth end of the controller 40.
Specifically, in the present embodiment, the switching device 30 is further provided with a first dc current limiting resistor R2 and a second dc current limiting resistor R3, so that the protection of the dc side of the ac load detection circuit is realized by the current limiting function of the two dc current limiting resistors, and the operational reliability of the ac load detection circuit is further improved.
Further, referring to fig. 4, in an embodiment, the switch device 30 further includes a bias resistor R4 and a pull-up resistor R5, a first end of the bias resistor R4 is connected to a second end of the light receiver of the optocoupler U1 and a first end of a first dc current-limiting resistor R2, a second end of the bias resistor R4 is connected to a third end of the switch device Q, a first end of the pull-up resistor R5 is connected to a first end of the second dc current-limiting resistor R3 and a first end of the switch device Q, a second end of the pull-up resistor R5 is connected to a first end of the light receiver of the optocoupler U1, and a common end of the pull-up resistor R5 is connected to the power supply.
Specifically, in the present embodiment, a bias resistor R4 is disposed between the second terminal of the switching device Q and the third terminal of the switching device Q, and the bias resistor R4 is adjusted to provide a base current with a proper magnitude for the switching device Q, so that the switching device Q obtains a proper operating point, and the emitter junction is forward biased, thereby effectively improving the operational reliability of the switching device Q. Meanwhile, a pull-up resistor R5 is disposed between the first end of the switching device Q and the power supply, so that when the switching device Q is in a cut-off state, the first end of the switching device Q can be effectively ensured to output a high-level signal to the fourth end of the controller 40, and the operational reliability of the switching device 30 is further improved.
In one embodiment, the ac load detection circuit further comprises an information prompting device, and the information prompting device is connected to the controller 40 (not shown).
Specifically, in this embodiment, the controller 40 is further connected to an information prompting device, and when the controller 40 analyzes the level signal output by the switch device 30 to obtain that the ac load 10 has a fault, the controller 40 outputs a prompting message through the information prompting device to notify the user of the fault state of the ac load 10 in time.
It should be noted that the specific type of the information prompting device is not exclusive, and in one embodiment, the information prompting device may be an audible alarm and/or an indicator light, etc., as long as the fault information of the ac load 10 can be timely notified to the user.
In the ac load detection circuit, when the ac load 10 is not in fault and the ac load detection circuit operates normally, the ac power flows into the ac load 10 through the live line L during the positive half cycle of the external ac power, then flows into the first end of the switching device 30 through the ac load 10, and flows back to the neutral line N through the second end of the switching device 30, so that the switching device 30 outputs the first level signal to the controller 40. When the external ac power source operates in the negative half cycle, the ac power source flows into the freewheeling diode 20 through the neutral line N, then flows into the ac load 10 through the freewheeling diode 20, and flows back to the live line L, and the switching device 30 has no power input and outputs another level signal to the controller 40. The controller 40 finally determines according to the level signal received in real time, that is, information on whether the ac load 10 has a fault can be directly obtained, so as to implement fault detection of the ac load 10. Through the scheme, the fault detection can be carried out on the alternating current load 10 in real time through the received level signal, and the fault detection can be known in time when the alternating current load 10 breaks down.
Referring to fig. 5, a method for detecting an ac load detection circuit is described above, and the method includes steps S100, S200, and S300.
And step S100, acquiring a level signal output by the switching device in real time.
Step S200, judging whether the level signal changes within a preset time length.
And step S300, outputting fault information of the AC load circuit breaking when the level signal is not changed within the preset time.
Specifically, the ac load 10 is a device that operates by ac power supplied from an ac power source and converts ac power into other forms of energy. When the ac power supply supplies power to the ac load 10, in the same cycle, the ac power supply includes both a positive half cycle in which power is supplied through the ac live line L and a negative half cycle in which power is supplied through the ac zero line N. When the ac power supply operates in the positive half cycle, due to the reverse blocking of the freewheeling diode 20, the ac power flowing from the live line L of the ac power supply flows into the second terminal of the ac load 10, flows out of the first terminal of the ac load 10, flows into the first terminal of the switching device 30, and flows back to the neutral line N of the external ac power supply from the second terminal of the switching device 30, so as to supply power to the ac load 10. In this process, the switching device 30 is powered to be in an operating state, and the third terminal of the switching device 30 is conducted to the ground terminal of the switching device 30, so that the switching device 30 outputs the first level signal to the controller 40. When the alternating current power supply works in a negative half cycle, due to the forward conduction of the freewheeling diode 20, the alternating current energy flowing out of the zero line N of the alternating current power supply flows in from the anode of the freewheeling diode 20, flows out from the cathode of the freewheeling diode 20, flows into the first end of the alternating current load 10, and flows back to the live line L of the external alternating current power supply from the second end of the alternating current load 10, so that the power supply to the alternating current load 10 is realized. In this process, no power flows between the first terminal and the second terminal of the switching device 30, the switching device 30 is in the off state, and the third terminal is not connected to the ground terminal of the switching device 30, so that the switching device 30 outputs the second level signal to the controller 40.
Since the external ac power source will switch back and forth between the positive half-cycle and the negative half-cycle during the normal power supplying process, the level signal received by the controller 40 from the switching device 30 will also switch back and forth between the first level signal and the second level signal. If the level signal received by the controller 40 within the preset time period does not change any more (the preset time period should be greater than or equal to the power cycle of the external ac power source), that is, it indicates that the ac load 10 is disconnected at this time, the controller 40 will output the fault information of the disconnection of the ac load 10, and may specifically notify the user through an information prompting device.
It should be noted that the predetermined duration is not unique in magnitude, and in one embodiment, the predetermined duration is the same as the period of the ac power source. Taking a 50Hz ac power supply as an example, the period of the ac power supply is 0.02 seconds, i.e. the positive half cycle of the ac power supply will output ac power from the live line L and the negative half cycle will output ac power from the neutral line N within 0.02 seconds.
Referring to fig. 6, in an embodiment, after the step S200, the method further includes: when the level signal changes within the preset time period, the process returns to step S100.
Specifically, when the level signal changes within the preset time period, that is, when the external ac power source switches between the positive half-cycle and the negative half-cycle, the output level of the switching device 30 received by the controller 40 also changes, and the external ac power source is in a normal operating state. The controller 40 returns to perform the operation of acquiring the level signal output by the switching device 30 in real time, so that the ac load 10 can be known in time when it is out of order.
Referring to fig. 7, in an embodiment, the detection method of the ac load detection circuit further includes step S400 and step S500.
Step S400, analyzing whether the AC load has a short-circuit fault according to the working state of the household appliance in which the AC load is positioned; and step S500, outputting fault information of the short circuit of the alternating current load when the short circuit fault of the alternating current load occurs.
Specifically, in this embodiment, the short-circuit fault detection operation of the ac load 10 can also be realized by the controller 40, and at this time, the short-circuit fault detection of the ac load 10 is performed in combination with the operating state of the household appliance in which the ac load 10 is located. In the operation process, if an alternating current section short circuit occurs, the fuse tube is fused, and the whole household appliance can be in an out-of-operation state; if a short circuit of the direct current section occurs, for example, a short circuit of +12V or +5V, the electric appliance will also be in a non-operating state. Therefore, the controller 40 only needs to obtain and analyze the working state of the household appliance after being powered on, and can obtain the detection result of whether the short-circuit fault occurs in the ac load 10. When the controller 40 analyzes that the ac load 10 has a short-circuit fault, it will output a fault message of the short-circuit of the ac load 10 to notify the user, and specifically may notify the user through an information prompting device.
Referring to fig. 8, in one embodiment, step S400 includes step S410 and step S420.
Step S410, acquiring working parameters of household electrical appliance where the alternating current load is located; step S420, whether the household appliance works normally is analyzed according to the working parameters; the normal work of the household electrical appliance indicates that the short-circuit fault does not occur in the alternating current load, and the abnormal work of the household electrical appliance indicates that the short-circuit fault occurs in the alternating current load.
Specifically, the obtaining manner of the working state of the household electrical appliance where the ac load 10 is located is not unique, and since certain differences exist in the working parameters (such as voltage, current, and the like) inside the household electrical appliance when the household electrical appliance is in the normal working state or in the abnormal working state, in this embodiment, whether the household electrical appliance is working normally is analyzed and determined by obtaining the working parameters of the household electrical appliance, and when the household electrical appliance is not working normally, the ac load 10 is considered to be in the short-circuit state, otherwise, the ac load 10 is considered to be running normally.
In the detection method of the ac load detection circuit, when the ac load 10 is not in fault and the ac load detection circuit operates normally, the ac power flows into the ac load 10 through the live line L during the positive half cycle of the external ac power, then flows into the first end of the switching device 30 through the ac load 10, and flows back to the neutral line N through the second end of the switching device 30, so that the switching device 30 outputs the first level signal to the controller 40. When the external ac power source operates in the negative half cycle, the ac power source flows into the freewheeling diode 20 through the neutral line N, then flows into the ac load 10 through the freewheeling diode 20, and flows back to the live line L, and the switching device 30 has no power input and outputs another level signal to the controller 40. The controller 40 finally determines according to the level signal received in real time, that is, information on whether the ac load 10 has a fault can be directly obtained, so as to implement fault detection of the ac load 10. Through the scheme, the fault detection can be carried out on the alternating current load 10 in real time through the received level signal, and the fault detection can be known in time when the alternating current load 10 breaks down.
A household appliance comprises the alternating current load detection circuit, and a controller 40 is used for carrying out fault detection on the alternating current load 10 according to the detection method.
Specifically, as shown in the above embodiments and the accompanying drawings, the ac load 10 is a device that operates by the ac power supplied by the ac power supply and converts the ac power into other forms of energy. When the ac power supply supplies power to the ac load 10, in the same cycle, the ac power supply includes both a positive half cycle in which power is supplied through the ac live line L and a negative half cycle in which power is supplied through the ac zero line N. When the ac power supply operates in the positive half cycle, due to the reverse blocking of the freewheeling diode 20, the ac power flowing from the live line L of the ac power supply flows into the second terminal of the ac load 10, flows out of the first terminal of the ac load 10, flows into the first terminal of the switching device 30, and flows back to the neutral line N of the external ac power supply from the second terminal of the switching device 30, so as to supply power to the ac load 10. In this process, the switching device 30 is powered to be in an operating state, and the third terminal of the switching device 30 is conducted to the ground terminal of the switching device 30, so that the switching device 30 outputs the first level signal to the controller 40. When the alternating current power supply works in a negative half cycle, due to the forward conduction of the freewheeling diode 20, the alternating current energy flowing out of the zero line N of the alternating current power supply flows in from the anode of the freewheeling diode 20, flows out from the cathode of the freewheeling diode 20, flows into the first end of the alternating current load 10, and flows back to the live line L of the external alternating current power supply from the second end of the alternating current load 10, so that the power supply to the alternating current load 10 is realized. In this process, no power flows between the first terminal and the second terminal of the switching device 30, the switching device 30 is in the off state, and the third terminal is not connected to the ground terminal of the switching device 30, so that the switching device 30 outputs the second level signal to the controller 40.
Since the external ac power source will switch back and forth between the positive half-cycle and the negative half-cycle during the normal power supplying process, the level signal received by the controller 40 from the switching device 30 will also switch back and forth between the first level signal and the second level signal. If the level signal received by the controller 40 within the preset time period does not change any more (the preset time period should be greater than or equal to the power cycle of the external ac power source), that is, it indicates that the ac load 10 is disconnected at this time, the controller 40 will output the fault information of the disconnection of the ac load 10, and may specifically notify the user through an information prompting device.
It should be noted that the specific type of the household appliance is not exclusive, and in one embodiment, the household appliance may be a household appliance using an ac heating tube, an ac shaded pole motor or an ac halogen lamp as the ac load 10, such as an electric water heater.
In the household electrical appliance, when the ac load 10 is not in fault and the ac load detection circuit operates normally, during a positive half cycle of the external ac power, the ac power flows into the ac load 10 through the live line L, then flows into the first end of the switching device 30 through the ac load 10, and flows back to the neutral line N through the second end of the switching device 30, so that the switching device 30 outputs a first level signal to the controller 40. When the external ac power source operates in the negative half cycle, the ac power source flows into the freewheeling diode 20 through the neutral line N, then flows into the ac load 10 through the freewheeling diode 20, and flows back to the live line L, and the switching device 30 has no power input and outputs another level signal to the controller 40. The controller 40 finally determines according to the level signal received in real time, that is, information on whether the ac load 10 has a fault can be directly obtained, so as to implement fault detection of the ac load 10. Through the scheme, the fault detection can be carried out on the alternating current load 10 in real time through the received level signal, and the fault detection can be known in time when the alternating current load 10 breaks down.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the claims. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (12)
1. An alternating current load detection circuit, comprising:
an alternating current load;
the first end of the alternating current load is connected with the cathode of the freewheeling diode, the second end of the alternating current load is connected with the live wire of an external alternating current power supply, and the anode of the freewheeling diode is connected with the zero line of the external alternating current power supply;
a first end of the switch device is connected with a cathode of the freewheeling diode, a second end of the switch device is connected with an anode of the freewheeling diode, a third end of the switch device is connected with a power supply, and a grounding end of the switch device is grounded;
a first end of the controller is connected with a second end of the alternating current load, a second end of the controller is connected with a zero line of the external alternating current power supply, a third end of the controller is connected with the power supply, a fourth end of the controller is connected with a fourth end of the switching device, and a grounding end of the controller is grounded;
the switching device is used for outputting a corresponding level signal to the controller according to the power supply half cycle where the external alternating current power supply is located, and the controller is used for judging whether the alternating current load has a fault according to the level signal.
2. The ac load detection circuit according to claim 1, further comprising a fuse, wherein the second terminal of the ac load is connected to the live line of the external ac power source through the fuse.
3. The ac load detection circuit according to claim 1, wherein the switching device includes an optical coupler device and a switching device, a first end of a light emitter of the optical coupler device serves as a first end of the switching device, a second end of the light emitter of the optical coupler device serves as a second end of the switching device, a first end of a light receiver of the optical coupler device is connected to the first end of the switching device, a common end of the first end of the light receiver of the optical coupler device serves as a third end of the switching device, a second end of the light receiver of the optical coupler device is connected to the second end of the switching device and the third end of the switching device, the third end of the switching device serves as a ground end of the switching device, and the first end of the switching device serves as a fourth end of the switching device.
4. The ac load detection circuit according to claim 3, wherein the switching device further includes a first dc current limiting resistor and a second dc current limiting resistor, a second end of the light receiver of the optical coupler device is connected to a first end of the first dc current limiting resistor and a third end of the switching device, a second end of the first dc current limiting resistor is connected to a second end of the switching device, a first end of the switching device is connected to a first end of the second dc current limiting resistor and the power supply, and a second end of the second dc current limiting resistor is connected to a fourth end of the controller.
5. The AC load detection circuit according to claim 4, wherein the switch device further comprises a bias resistor and a pull-up resistor, a first end of the bias resistor is connected to the second end of the light receiver of the opto-coupler device and the first end of the first DC current-limiting resistor, a second end of the bias resistor is connected to the third end of the switch device, a first end of the pull-up resistor is connected to the first end of the second DC current-limiting resistor and the first end of the switch device, a second end of the pull-up resistor is connected to the first end of the light receiver of the opto-coupler device, and a common end of the pull-up resistor is connected to the power supply.
6. The alternating current load detection circuit according to any one of claims 1 to 5, further comprising an alternating current limiting resistor, wherein a first end of the alternating current limiting resistor is connected to a first end of the alternating current load and a cathode of the freewheeling diode, and a second end of the alternating current limiting resistor is connected to an anode of the freewheeling diode.
7. The ac load detection circuit of claim 1, further comprising an information prompting device, said information prompting device being connected to said controller.
8. A method of testing an ac load sensing circuit, the ac load sensing circuit as claimed in any one of claims 1 to 7, the method comprising:
acquiring a level signal output by the switching device in real time;
judging whether the level signal changes within a preset time length;
and outputting fault information of the AC load circuit breaking when the level signal is not changed within the preset time.
9. The method according to claim 8, wherein after the step of determining whether the level signal changes within a preset time period, the method further comprises:
and when the level signal changes within a preset time length, returning to the step of acquiring the level signal output by the switching device in real time.
10. The detection method according to claim 8, further comprising:
analyzing whether the alternating current load has a short-circuit fault or not according to the working state of the household appliance in which the alternating current load is positioned;
and when the AC load has a short-circuit fault, outputting fault information of the short circuit of the AC load.
11. The method according to claim 10, wherein the step of analyzing whether the ac load has a short-circuit fault according to the operating status of the household electrical appliance in which the ac load is located comprises:
acquiring working parameters of household electrical appliance where the alternating current load is located;
and analyzing whether the household appliance works normally or not according to the working parameters, wherein the normal working of the household appliance represents that the alternating current load does not have the short-circuit fault, and the abnormal working of the household appliance represents that the alternating current load has the short-circuit fault.
12. An electrical home appliance comprising the ac load detection circuit according to any one of claims 1 to 7, wherein the controller is configured to perform fault detection on the ac load according to the detection method according to any one of claims 8 to 11.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110516025.7A CN113156333A (en) | 2021-05-12 | 2021-05-12 | Alternating current load detection circuit and detection method thereof, and household appliance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110516025.7A CN113156333A (en) | 2021-05-12 | 2021-05-12 | Alternating current load detection circuit and detection method thereof, and household appliance |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN113156333A true CN113156333A (en) | 2021-07-23 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110516025.7A Pending CN113156333A (en) | 2021-05-12 | 2021-05-12 | Alternating current load detection circuit and detection method thereof, and household appliance |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113156333A (en) |
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2021
- 2021-05-12 CN CN202110516025.7A patent/CN113156333A/en active Pending
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