CN115542786A

CN115542786A - Heating fault detection circuit, heating fault detection method and household appliance

Info

Publication number: CN115542786A
Application number: CN202110737426.5A
Authority: CN
Inventors: 刘小勇; 肖磊; 雷俊; 梁显堂; 陈连城; 徐少承; 刘锦泉; 刘万; 余水秀
Original assignee: Guangdong Midea Consumer Electric Manufacturing Co Ltd
Current assignee: Guangdong Midea Consumer Electric Manufacturing Co Ltd
Priority date: 2021-06-30
Filing date: 2021-06-30
Publication date: 2022-12-30

Abstract

The application discloses heating fault detection circuit, heating fault detection method and tame electric installation, the heating fault detection circuit that this application provided includes: and a first end of the controllable switch is connected with the power supply end, and a second end of the controllable switch is connected with the heating end to form a heating loop. And the first end of the first resistor is connected with the second end of the controllable switch. And the control circuit is connected with the second end of the first resistor, the control end of the controllable switch and the heating control signal input end and is used for controlling the conduction of the controllable switch according to the heating control signal input by the heating control signal input end. And the detection circuit is connected with the first end of the first resistor, the second end of the first resistor and the heating detection signal output end and is used for outputting a heating detection signal from the heating detection signal output end according to the current flow direction of the first resistor. The fault condition of the heating circuit can be detected at low cost.

Description

Heating fault detection circuit, heating fault detection method and household appliance

Technical Field

The present disclosure relates to heating detection technologies, and particularly to a heating fault detection circuit, a heating fault detection method, and a household appliance.

Background

The commonly used heating current detection method is to collect the loop current by a current transformer or a small resistance sampling method (such as a constantan wire or an alloy resistor), and simultaneously judge whether the heating loop has abnormity or faults according to the magnitude of the current. In the heating process of the silicon controlled rectifier, the specific heating current value is not actually required to be detected in the heating fault detection, and the current transformer or the operational amplifier is required to be added in the detection circuit, so that the cost is higher.

Disclosure of Invention

The heating fault detection circuit, the heating fault detection method and the household appliance mainly solve the technical problem that the cost of the heating fault detection circuit can be reduced.

A technical scheme that this application adopted provides a heating fault detection circuit, and heating fault detection circuit includes: and a first end of the controllable switch is connected with the power supply end, and a second end of the controllable switch is connected with the heating end to form a heating loop. And the first end of the first resistor is connected with the second end of the controllable switch. And the control circuit is connected with the second end of the first resistor, the control end of the controllable switch and the heating control signal input end and is used for controlling the conduction of the controllable switch according to the heating control signal input by the heating control signal input end. And the detection circuit is connected with the first end of the first resistor, the second end of the first resistor and the heating detection signal output end and is used for outputting a heating detection signal from the heating detection signal output end according to the current flow direction of the first resistor.

Further, the control circuit includes: and the first switch circuit is connected with the second end of the first resistor and the control end of the controllable switch. And the second switch circuit is connected with the first switch circuit and the heating control signal input end. The second switch circuit is conducted in response to the heating control signal being at a preset level, and further controls the first switch circuit to be conducted so as to further control the controllable switch to be conducted.

Further, the first switching circuit includes: and a first end of the bidirectional optical coupling switch is connected with a second end of the first resistor, and a second end of the bidirectional optical coupling switch is connected with a control end of the controllable switch. And the anode of the first light-emitting diode is connected with the reference voltage end, and the cathode of the first light-emitting diode is grounded through the second switch circuit.

Further, the second switching circuit includes: and the control end of the switch tube is connected with the heating control signal input end, the collector of the switch tube is connected with the cathode of the first light-emitting diode, and the emitter of the switch tube is grounded.

Further, the first switching circuit further includes: and the first end of the second resistor is connected with the reference voltage end, and the second end of the second resistor is connected with the anode of the first light-emitting diode. And/or the second switching circuit further comprises: and the first end of the third resistor is connected with the control end of the switching tube, and the second end of the third resistor is connected with the heating control signal input end. And the first end of the fourth resistor is connected with the control end of the switching tube, and the second end of the fourth resistor is grounded.

Further, the detection circuit includes: and the anode of the diode is connected with the second end of the first resistor. And the third switching circuit is connected with the cathode of the diode, the first end of the first resistor and the heating detection signal output end. The third switch circuit is used for being switched on or off according to the current flow direction of the first resistor so as to output the heating detection signal from the heating detection signal output end.

Further, the third switch circuit includes: and the anode of the second light-emitting diode is connected with the cathode of the diode, and the cathode of the second light-emitting diode is connected with the first end of the first resistor. And the collector of the phototriode is connected with the reference voltage end and the heating detection signal output end, and the emitter of the phototriode is grounded.

Further, the third switch circuit includes: and a first end of the fifth resistor is connected with the cathode of the diode, and a second end of the fifth resistor is connected with the anode of the second light-emitting diode. And the first end of the sixth resistor is connected with the collector of the phototriode, and the second end of the sixth resistor is connected with the reference voltage end. And the first end of the seventh resistor is connected with the collector of the phototriode, and the second end of the seventh resistor is connected with the heating detection signal output end. And the first end of the capacitor is connected with the collector of the phototriode, and the second end of the capacitor is grounded.

In order to solve the above technical problem, another technical solution adopted in the present application is to provide a heating fault detection method, where the heating fault detection method is applied to the heating fault detection circuit, and the heating fault detection method includes: an alternating current signal is supplied to the power supply terminal. And inputting a heating control signal to the heating control signal input end. And acquiring a heating detection signal output by the heating detection signal output end. And determining the fault condition of the heating circuit according to the heating detection signal.

In order to solve the above technical problem, another technical scheme adopted by the present application is to provide a household electrical appliance, which includes: and a heating failure detection circuit, which is the heating failure detection circuit. And the controller is connected with the heating fault detection circuit and is used for executing the heating fault detection method.

The beneficial effect of this application is: different from prior art, the heating fault detection circuit that this application provided includes: and a first end of the controllable switch is connected with the power supply end, and a second end of the controllable switch is connected with the heating end to form a heating loop. And the first end of the first resistor is connected with the second end of the controllable switch. And the control circuit is connected with the second end of the first resistor, the control end of the controllable switch and the heating control signal input end and is used for controlling the conduction of the controllable switch according to the heating control signal input by the heating control signal input end. And the detection circuit is connected with the first end of the first resistor, the second end of the first resistor and the heating detection signal output end and is used for outputting a heating detection signal from the heating detection signal output end according to the current flow direction of the first resistor. The heating fault detection circuit provided by the embodiment does not need to add a current transformer or an operational amplifier, so that the fault condition of the heating loop can be detected at low cost.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts. Wherein:

FIG. 1 is a schematic diagram of an embodiment of a heating fault detection circuit provided in the present application;

FIG. 2 is a schematic block diagram of another embodiment of a heating fault detection circuit provided herein;

FIG. 3 is a schematic block diagram of another embodiment of a heating fault detection circuit provided herein;

FIG. 4 is a schematic flow chart diagram illustrating one embodiment of a heating fault detection method provided herein;

fig. 5 is a signal diagram of an embodiment of an ac signal, a heating control signal, and a heating detection signal when N = 1;

fig. 6 is a signal diagram of an embodiment of the ac signal, the heating control signal, and the heating detection signal when N = 3;

fig. 7 (a) is a signal diagram of an embodiment of an ac signal, a heating control signal, and a heating detection signal when N = 2;

fig. 7 (b) is a signal diagram of another embodiment of the alternating current signal, the heating control signal, and the heating detection signal when N = 2;

fig. 8 is a signal diagram of an embodiment of an ac signal, a heating control signal, and a heating detection signal when N =4,m = 2;

FIG. 9 is a schematic flow chart diagram illustrating another embodiment of a heating fault detection method provided herein;

fig. 10 is a schematic structural diagram of an embodiment of a home appliance provided in the present application;

FIG. 11 is a schematic structural diagram of an embodiment of a computer-readable storage medium provided in the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. It is to be understood that the specific embodiments described herein are merely illustrative of and not restrictive on the broad application. It should be further noted that, for the convenience of description, only some of the structures related to the present application are shown in the drawings, not all of the structures. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The terms "first", "second" and "first" in this application are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or as implying any indication of the number of technical features shown. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. Furthermore, the terms "include" and "have," as well as any variations thereof, are intended to cover a non-exclusive inclusion. A process, method, system, article, or apparatus that optionally comprises a list of steps or elements is not limited to only those steps or elements recited, but may optionally include additional steps or elements not recited, or may optionally include additional steps or elements inherent to such process, method, article, or apparatus.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein may be combined with other embodiments.

The electromagnetic oven, electric pressure cooker, electric rice cooker and other household appliances utilize the magnetic force lines generated by the coil panel to cut the pot to generate vortex current, and the joule heat effect of the vortex current heats the pot, thereby realizing heating. The induction cooker has become a cooking utensil with high use frequency in people's life due to the advantages of convenient and fast heating, no open fire and the like.

A Heating circuit for Heating in an Induction cooker generally includes a resonant circuit and an Insulated Gate Bipolar Transistor (IGBT), and the Induction cooker controls the IGBT to oscillate the resonant circuit, so that a current with high frequency change is formed on a coil panel in the resonant circuit, and a magnetic field is generated, and electromagnetic Heating (IH) is realized by cutting a pot by magnetic lines of force of the magnetic field. In the conventional IH system, the power tube IGBT is easily damaged under overcurrent conditions, so that induction cookers on the market generally have a current sampling circuit to monitor the current change during the operation of the IH device. At present, a common current sampling circuit mainly comprises a mutual inductor current sampling circuit and a metal film resistance voltage division sampling circuit. However, the transformer current sampling circuit needs to adopt a transformer for sampling, so that the cost is high. The metal film resistor voltage division sampling circuit needs to adopt a plurality of resistors for sampling, so that the occupied space is large, and the power consumption and the heat productivity of the circuit are also large.

Accordingly, the present embodiment provides a heating fault detection circuit that can detect whether a heating circuit is abnormal at low cost without installing a current transformer or an operational amplifier.

Specifically, referring to fig. 1, fig. 1 is a schematic structural diagram of an embodiment of a heating fault detection circuit provided in the present application, and as shown in fig. 1, a heating fault detection circuit 100 provided in the present application includes a controllable switch 10, a first resistor 20, a control circuit 30, and a detection circuit 40.

Wherein, a first terminal of the controllable switch 10 is connected to the power source terminal AC, and a second terminal of the controllable switch 10 is connected to the heating terminal HEAT, so as to form a heating loop.

In the present embodiment, the heating terminal HEAT is one terminal connected to a load, and the heating fault detection circuit 100 provided in the present embodiment is used to connect to the load and HEAT the load, and optionally, the load may be a pot such as an induction cooker, an electric pressure cooker, or an electric cooker.

In this embodiment, if the heating circuit is normal, the heating operation on the load can be performed, whereas if the heating circuit is abnormal, the heating operation on the load cannot be performed, so the heating failure detection circuit 100 provided in this embodiment detects a failure condition of the heating circuit.

In this embodiment, the controllable switch 10 may be a thyristor switch. A Silicon Controlled Rectifier (SCR) is a high-power electrical component, also called a thyristor, and has the advantages of small volume, high efficiency, long service life, and the like. The prior silicon controlled rectifier mainly has a full plane, a single boss, a double boss and the like, and the optimization direction mainly lies in reducing high-temperature electric leakage, improving voltage change rate, adjusting dynamic current during turn-off and the like. In this embodiment, the thyristor switch may be a unidirectional thyristor switch or a bidirectional thyristor switch. The silicon controlled switch mainly has the following two modes, namely a wave-dropping control mode and a chopping control mode, and the two modes can enable the silicon controlled switch to realize the adjustment control of the load power.

The operating principle of the silicon controlled switch is that the on-off time ratio of the alternating current power supply is controlled by controlling the conduction angle of the silicon controlled switch. In fact, the larger the conduction angle of the thyristor switch is, the longer the delay time of the thyristor switch is, the smaller the on-off time ratio of the alternating current power supply is, and the smaller the preset power corresponding to the conduction angle is. Alternatively, the conduction angle of the thyristor switch may be 20 °, 30 ° or 40 °. By controlling the size of the conduction angle, a preset power corresponding to the conduction angle can be determined. Of course, the conduction angle of the thyristor switch may be any other angle, and is not limited in detail herein.

A second terminal of the controllable switch 10 is connected to a first terminal of a first resistor 20.

The second end of the first resistor 20, the control end of the controllable switch 10, and the heating control signal input end TRIAC are connected to the control circuit 30, and are configured to control the conduction of the controllable switch 10 according to the heating control signal input by the heating control signal input end TRIAC.

In the present embodiment, the control circuit 30 turns on the controllable switch 10 through the input heating control signal, so that the ac signal flows to the heating end HEAT through the controllable switch 10, so as to HEAT the load such as the induction cooker, the electric pressure cooker, and the electric rice cooker.

The first terminal of the first resistor 20, the second terminal of the first resistor 20, and the heating detection signal output terminal JNT _ HEAT are connected to the detection circuit 40.

The detection circuit 40 is configured to output a heating detection signal from the heating detection signal output terminal JNT _ HEAT according to the flowing direction of the current of the first resistor 20.

Specifically, the heating detection signal is output by controlling the detection circuit 40 according to the flowing direction of the current flowing through the first resistor 10 by connecting a resistor, i.e., the first resistor 20, in series in the driving circuit of the controllable switch 10.

The current flowing through the first resistor 10 may flow in a direction from the first terminal of the first resistor 10 to the second terminal of the first resistor 10, or from the second terminal of the first resistor 10 to the first terminal of the first resistor 10.

In summary, the heating fault detection circuit provided in this embodiment controls the controllable switch to be turned on and off through the heating control signal input from the heating control signal input terminal, so as to influence the current flow direction of the first resistor, and further determines whether the heating circuit is abnormal according to the heating detection signal detected from the heating detection signal output terminal.

Optionally, referring to fig. 1 and fig. 2 simultaneously, fig. 2 is a schematic structural diagram of another embodiment of the heating fault detection circuit provided in the present application, and as shown in the drawing, the control circuit 30 includes a first switch circuit 31 and a second switch circuit 32.

Wherein the second terminal of the first resistor 20 and the control terminal of the controllable switch 10 are connected to a first switch circuit 31.

The first switch circuit 31 and the heating control signal input terminal TRIAC are connected to the second switch circuit 32.

The second switch circuit 32 is turned on in response to the heating control signal being at a predetermined level, and further controls the first switch circuit 31 to be turned on, so as to further control the controllable switch 10 to be turned on. In this embodiment, the heating control signal may be high or low.

The detection circuit 40 includes a diode 42 and a third switch circuit 41.

The second end of the first resistor 20 is connected to the anode of the diode 42.

The anode of the diode 42, the first end of the first resistor 20, and the heating detection signal output terminal JNT _ HEAT are connected to the third switching circuit 41.

The third switch circuit 41 is configured to be turned on or off according to a flowing direction of the current flowing through the first resistor 20, so as to output the heating detection signal from the heating detection signal output terminal JNT _ HEAT.

In this embodiment, whether the heating failure detection circuit 100 outputs the heating detection signal or not may be detected by a controller such as an MCU, and if so, it indicates that the heating circuit is normal.

In an embodiment, referring to fig. 1, fig. 2, and fig. 3 are schematic structural diagrams of a further embodiment of the heating fault detection circuit provided in the present application, as shown in the figure, the first switch circuit 31 includes a bidirectional optocoupler switch 311 and a first light emitting diode 312.

The second end of the first resistor 20 is connected to the second end of the bidirectional optocoupler switch 311, and the control end of the controllable switch 10 is connected to the first end of the bidirectional optocoupler switch 311.

The anode of the first light emitting diode 312 is connected to the reference voltage terminal V1, and the cathode of the first light emitting diode 312 is grounded through the second switch circuit 32.

The second switch circuit 32 may include a switch 321, a heating control signal input terminal TRIAC connected to a control terminal of the switch 321, a cathode of the first light emitting diode 312 connected to a collector of the switch 321, and an emitter of the switch 321 connected to ground. The switch 321 is turned on or off according to a preset level of the heating control signal inputted from the control terminal thereof.

Optionally, the first switch circuit 31 further includes a second resistor 313, and the reference voltage terminal V1 is connected to a first terminal of the second resistor 313.

In this embodiment, the second resistor 313 can perform a voltage division function, and the reference voltage terminal V1 may be 5V.

The anode of the first led 312 is connected to the second end of the second resistor 313.

And/or the second switching circuit 32 may further include a third resistor 322 and a fourth resistor 323.

The control end of the switching tube 321 is connected to the first end of the third resistor 322, and the heating control signal input end TRIAC is connected to the second end of the third resistor 322.

The control terminal of the switching tube 321 is connected to the first terminal of the fourth resistor 323, and the second terminal of the fourth resistor 323 is grounded.

The detection circuit 40 includes a diode 42 and a third switch circuit 41.

Wherein, the second terminal of the first resistor 20 is connected to the anode of the diode 42.

The cathode of the diode 42, the first end of the first resistor 20, and the heating detection signal output terminal JNT _ HEAT are connected to the third switching circuit 41.

Specifically, the third switching circuit 41 includes a second light emitting diode 411 and a phototransistor 412.

The cathode of the diode 42 is connected to the anode of the second light emitting diode 411, and the first end of the first resistor 20 is connected to the cathode of the second light emitting diode 411.

The collector of the phototransistor 412 is connected to the reference voltage terminal V1 and the heating detection signal output terminal JNT _ HEAT, and the emitter of the phototransistor 412 is grounded.

Optionally, the third switch circuit 41 may further include a fifth resistor 413, a sixth resistor 414, a seventh resistor 415, and a capacitor 416.

The cathode of the diode 42 is connected to the first end of the fifth resistor 413, and the anode of the second light emitting diode 411 is connected to the second end of the fifth resistor 413.

The collector of the phototransistor 412 is coupled to a first terminal of a sixth resistor 414, and a reference voltage terminal V1 is coupled to a second terminal of the sixth resistor 414.

The collector of the phototransistor 412 is connected to a first terminal of the seventh resistor 415, and the heating detection signal output terminal JNT _ HEAT is connected to a second terminal of the seventh resistor 415.

The collector of the phototransistor 412 is coupled to a first terminal of a capacitor 416, and a second terminal of the capacitor 416 is coupled to ground.

In the present embodiment, the operation principle of the heating fault detection circuit 100 is:

when the alternating current signal crosses zero and the input heating control signal is at a low level, the bidirectional optocoupler switch 311 of the control circuit 30 is not turned on, the controllable switch 10 is not turned on, the voltages at the two ends of the first resistor 20 are equal, the phototriode 412 is not turned on, the heating detection signal output end JNT _ HEAT maintains a high level, and the heating detection signal is not output. That is, when the heating control signal is at a low level, the heating circuit is not turned on, and the heating failure detection circuit 100 cannot output the heating detection signal regardless of whether the heating circuit is normal or abnormal.

When the alternating current signal crosses zero and the input heating control signal is at a high level, the switching tube 321 is turned on, the bidirectional optocoupler switch 311 of the control circuit 30 is turned on, and the controllable switch 10 is turned on. When the negative half wave of the alternating current signal is conducted, the current sequentially passes through the bidirectional optocoupler switch 311, the second end of the first resistor 20 and the first end of the first resistor 20 from the control end of the controllable switch 10, so that the voltage of the second end of the first resistor 20 is higher than the voltage of the first end of the first resistor 20, the second light emitting diode 411 is conducted, the heating detection signal output end JNT _ HEAT is changed from high level to low level, a heating detection signal is generated, and the microprocessor detects the heating detection signal to indicate that the heating loop works normally. In summary, when the heating control signal is at a high level, if the voltage at the second end of the first resistor 20 is higher than the voltage at the first end of the first resistor 20, the heating detection signal can be output when the heating circuit is normal.

When the alternating current signal crosses zero, and the input heating control signal is at a high level, the switching tube 321 is turned on, the bidirectional optical coupling switch 311 of the control circuit 30 is turned on, and the controllable switch 10 is turned on. When the positive half wave of the alternating current signal is conducted, current flows from the first end of the first resistor 20, the second end of the first resistor 20, the bidirectional optical coupler switch 311 and the control end of the controllable switch 10. Therefore, the voltage of the second terminal of the first resistor 20 is lower than the voltage of the first terminal of the first resistor 20, and the second light emitting diode 411 is not turned on, so that the heating detection signal output terminal JNT _ HEAT will maintain a high level, and cannot generate a heating detection signal, the microprocessor cannot detect the heating detection signal, and further cannot determine whether the heating circuit is working normally. In summary, when the heating control signal is at a high level, if the voltage at the second end of the first resistor 20 is lower than the voltage at the first end of the first resistor 20, the heating detection signal cannot be output regardless of whether the heating circuit is normal or abnormal.

In summary, when the input heating control signal is at a high level, the heating fault detection circuit 100 may output the heating detection signal, specifically, when the voltage at the second end of the first resistor 20 is higher than the voltage at the first end of the first resistor 20, if the heating circuit does not fault at this time, the heating detection signal output terminal JNT _ HEAT may output the heating detection signal, and conversely, if the heating detection signal output terminal JNT _ HEAT cannot output the heating detection signal, it indicates that the heating circuit is faulty. When the voltage of the second end of the first resistor 20 is lower than the voltage of the first end of the first resistor 20, the heating fault detection circuit 100 cannot output the heating detection signal, and at this time, it cannot determine whether the heating circuit is normal.

In summary, the heating fault detection circuit provided in this embodiment controls the controllable switch to be turned on and off according to the heating control signal input from the heating control signal terminal, so as to influence the current flow direction of the first resistor, and further determines whether the heating circuit is abnormal according to the heating detection signal detected from the heating detection signal output terminal.

Referring to fig. 4, fig. 4 is a schematic flow chart of an embodiment of a heating fault detection method provided in the present application, and the heating fault detection method provided in this embodiment is applied to the heating fault detection circuit provided in any one of the above embodiments, as shown in fig. 4, the method includes the following steps.

S101: an AC signal is input to a power source terminal.

In this embodiment, the alternating current signal may be a 220V commercial power, or may also be an alternating current signal after being processed by processing operations such as filtering, and optionally, the alternating current signal may be a sinusoidal signal, and of course, may also be any other alternating current signal, which is not limited specifically herein.

S102: and inputting the heating control signal to a heating control signal end.

In this embodiment, the heating control signal may be a pulse signal.

In this embodiment, the heating control signal is used to control the heating process, in particular by controlling the on or off of a controllable switch of the heating circuit.

Alternatively, the heating control signal may include a plurality of pulses arranged according to a preset timing, a starting point of a rising edge of the pulse corresponds to a zero-crossing point of the ac signal, and at least a part of the pulse corresponds to a negative half cycle of the ac signal.

It can be understood that, since the heating fault detection method provided by this embodiment is based on the heating fault detection circuit provided by the above embodiment, and the heating fault detection circuit is configured to turn on the negative half cycle of the ac signal to generate the heating detection signal when the input heating control signal is at the high level, and is not configured to generate the heating detection signal when the positive half cycle of the ac signal is turned on, at this time, even if the heating circuit is normal, it is not possible to determine whether the heating circuit is faulty. Therefore, the partial pulse of the heating control signal in this embodiment must correspond to the negative half cycle of the ac signal.

In one embodiment, the period of the ac signal is not set to T, and the heating control signal has a pulse every N × T/2, where N is an odd number. Alternatively, when N =1, referring to fig. 5, fig. 5 is a signal diagram of an embodiment of the ac signal, the heating control signal, and the heating detection signal when N =1, as shown in fig. 5, each negative half cycle of the ac signal is turned on by the heating control signal, and the heating failure detection circuit outputs one heating detection signal every T. Therefore, when N =1, if the heating detection signal can be detected within the preset time, it indicates that the heating circuit is normal, whereas if the heating detection signal is not detected within the preset time period, it indicates that the heating circuit is faulty. Since the heating monitoring signal output terminal outputs one heating detection signal every T, the preset time period may be T or greater than T.

In one embodiment, when N =3, referring to fig. 6, fig. 6 is a signal diagram of an embodiment of the ac signal, the heating control signal, and the heating detection signal when N =3, as shown in fig. 6, the heating control signal alternately turns on the positive half cycle and the negative half cycle of the ac signal, and the heating fault detection circuit outputs one heating detection signal every 3T. Therefore, when N =3, if the heating detection signal can be detected within the preset time, it indicates that the heating circuit is normal, whereas if the heating detection signal is not detected within the preset time period, it indicates that the heating circuit is faulty, and since the heating detection signal output terminal outputs one heating detection signal every 3T, the preset time period may be 3T or greater than 3T.

In another embodiment, still assuming that the period of the ac signal is T, in this embodiment, the heating control signal has a pulse every N × T/2, N is an even number, and each pulse corresponds to the negative half cycle of the ac signal.

Specifically, when N is an even number, all of the heating control signals may be turned on in the positive half cycle of the ac signal or in the negative half cycle of the ac signal, and in the present embodiment, N =2 is taken as an example. Referring to fig. 7 (a), fig. 7 (a) is a signal diagram of an embodiment of the ac signal, the heating control signal, and the heating detection signal when N =2, and as shown in fig. 7 (a), the heating detection signal is turned on for all negative half cycles of the ac signal, and the heating fault detection circuit outputs one heating detection signal every T. Referring to fig. 7 (b), fig. 7 (a) is a signal diagram of another embodiment of the ac signal, the heating control signal, and the heating detection signal when N =2, and as shown in fig. 7 (b), the heating detection signal is turned on for all positive half cycles of the ac signal, and in this case, the heating failure detection circuit does not output the heating detection signal even if the heating circuit is normal.

Therefore, in the present embodiment, each pulse of the heating control signal is set to correspond to the negative half cycle of the ac signal, so as to ensure that the heating fault detection method provided in this embodiment can detect the fault condition of the heating circuit.

Alternatively, each pulse may be made to correspond to a negative half cycle of the ac signal in order to prevent failure to detect a fault condition in the heating circuit.

Specifically, the heating control signal includes a first heating control signal and a second heating control signal.

Wherein, the first heating control signal has a pulse every NxT/2, N is an even number, and each pulse of the first heating control signal corresponds to the negative half cycle of the alternating current signal.

Wherein, the second heating control signal has a pulse every NxT/2, N is an even number, and each pulse of the second heating control signal corresponds to the positive half cycle of the alternating current signal.

Optionally, step S102 may specifically be:

the second heating control signal is input first, and then the first heating control signal is input. Specifically.

In this embodiment, if the second heating control signal is input first, it is not possible to detect whether the heating circuit is normal.

At this time, the first heating control signal may be input, and if the heating loop is normal, the heating detection signal may be generated, and if the heating detection signal is not acquired, there are two possible situations.

The first case is: the first heating control signal is input, but the heating detection signal is not output because the heating circuit is failed.

The second case is: the second heating control signal is input, if the second condition is met, in order to judge the fault condition of the heating circuit, the heating control signal different from the first input heating control signal, namely the first heating control signal is input into the heating fault detection circuit again, because each pulse of the heating control signal corresponds to the negative half cycle of the alternating current signal, whether the heating detection signal is output is judged again, if yes, the heating circuit is determined to be normal, and if not, the heating circuit is determined to be in fault.

Specifically, if the second heating control signal is input, the timing of inputting the first heating control signal may be different according to N. Optionally, when N is 2, if the first heating control signal is input, if the heating loop is normal, the heating fault detection circuit should output one heating detection signal every T, and therefore, if the heating detection signal is not acquired within the preset time period, it indicates that the second heating control signal is input.

At this time, the first heating control signal is input, and the preset time period at least needs to be greater than T. If the heating detection signal is still not detected within the preset time period after the first heating control signal is input, the heating loop is indicated to be in fault. Alternatively, the time for inputting the first heating control signal needs to be greater than 2T when N =4, greater than 3T when N =6, \8230 \ 8230;, greater than KT when N is 2K, and a positive integer K. In this embodiment, the heating fault detection circuit is determined twice to output the heating detection signal, so as to further determine whether the heating circuit is operating normally.

In another embodiment, let the period of the ac signal be T.

In this embodiment, the heating control signal has M consecutive pulses every N × T/2.

In this embodiment, N is a positive integer greater than 2, and M is a positive integer greater than 1 and less than N.

In this embodiment, since M is a positive integer of 1, it is understood that 2 or more pulses in succession can conduct at least 2 consecutive half cycles of the alternating current signal, and according to the characteristics of the alternating current signal, if the alternating current signal is otherwise a sinusoidal alternating current signal, the sinusoidal alternating current signal has a signal characteristic of alternating positive and negative half cycles, the at least 2 half cycles include at least one negative half cycle, alternatively, every two consecutive half cycles of the sinusoidal alternating current signal include one negative half cycle, and every three consecutive half cycles of the sinusoidal alternating current signal may include one negative half cycle, and may also include two negative half cycles, and the negative half cycle of the alternating current signal is conducted, and at this time, if the heating circuit is not failed, the heating detection signal can be output. That is, if the heating detection signal can be detected, it indicates that the heating circuit has no fault, otherwise, if the heating detection signal is not detected at the heating detection signal output end within the preset time period, it indicates that the heating circuit has a fault.

Referring to fig. 8, fig. 8 is a signal diagram illustrating an embodiment of the ac signal, the heating control signal, and the heating detection signal when N =4,m =2, and as shown in fig. 8, when N =4,m =2, it indicates that the heating control signal has 2 consecutive pulses per 2T, and at this time, the 2 consecutive pulses can conduct the positive half cycle and the negative half cycle of the ac signal, so that the circuit can output one heating detection signal per 2T when the heating circuit is normal. That is, if the heating detection signal can be detected within the preset time period, it indicates that the heating circuit has no fault, otherwise, if the heating detection signal is not detected at the heating detection signal output end within the preset time period, it indicates that the heating circuit has a fault. In this embodiment, the preset time period may be adaptively adjusted according to the size of N, specifically, the preset time period increases with the increase of N, and in a specific embodiment, when N =4, the preset time period may be greater than or equal to 2T.

S103: and acquiring a heating detection signal output by the heating detection signal output end.

In this embodiment, depending on the type of the heating control signal, the heating detection signal output terminal may output the heating detection signal, which necessarily indicates that the heating circuit is normal, but the heating detection signal output terminal cannot indicate that the heating circuit is abnormal if the heating detection signal is not output. At this time, it is necessary to determine whether or not an abnormality occurs in the heating circuit based on the specific type of the heating control signal. Specifically, depending on the specific type of the heating control signal, if no heating detection signal is output, either the heating circuit is abnormal, or the heating control signal is conducted in the positive half cycle of the ac signal, so that the detection circuit cannot output the heating detection signal, and therefore it cannot determine whether the heating circuit is abnormal.

S104: and determining the fault condition of the heating circuit according to the heating detection signal.

In one embodiment, the alternating current signal has a period T, and the heating control signal has a pulse every N × T/2, where N is an odd number. For example, when N =1, the heating control signal has one pulse per T/2, when N =3, the heating control signal has one pulse per 3T/2, and so on.

At this time, if the heating detection signal can be detected within the preset time, it indicates that the heating circuit is normal, otherwise, if the heating detection signal is not detected within the preset time period, it indicates that the heating circuit is faulty.

Optionally, in this embodiment, the preset time period is increased according to an increase of N, and optionally, when N is 1, the preset time period may be a value greater than or equal to T, and when N is 3, the preset time period may be a value greater than or equal to 3T.

In one embodiment, the period of the ac signal is T, in this embodiment, the heating control signal has a pulse every N × T/2, N is an even number, and each pulse corresponds to the negative half cycle of the ac signal. For example, when N =2, the heating control signal has one pulse per T, when N =4, the heating control signal has one pulse per 2T, and so on.

At this time, if the heating detection signal can be detected within the preset time, it indicates that the heating circuit is normal, otherwise, if the heating detection signal is not detected within the preset time period, it indicates that the heating circuit is faulty. The preset time period increases according to an increase in N, and alternatively, when N is 2, the preset time period may be a value greater than or equal to T, and when N is 4, the preset time period may be a value greater than or equal to 2T.

In one embodiment, the heating control signal includes a first heating control signal and a second heating control signal.

Wherein, every N × T/2 of the second heating control signal has a pulse, N is an even number, and each pulse of the second heating control signal corresponds to a positive half cycle of the ac signal, and the input of the heating control signal to the heating control signal input terminal may specifically be:

the second heating control signal is input first, and then the first heating control signal is input.

Specifically, the second heating control signal is input first, and if the heating detection signal is not detected within the preset time period, the first heating control signal is input again, and whether the heating detection signal is detected is determined again, so that whether the heating loop is abnormal is determined according to the condition of the heating detection signal detected within the preset time period.

Specifically, the size value of the preset time period is determined by the size of N.

In one embodiment, the heating control signal has M consecutive pulses per N × T/2, N being a positive integer greater than 2, M being a positive integer greater than 1 and less than N. For example, when N =3, M =2, the heating control signal has two pulses per 3T/2, when N =4,m =2, the heating control signal has two pulses per 2T, and so on.

At this time, if the heating detection signal can be detected within the preset time, it indicates that the heating circuit is normal, otherwise, if the heating detection signal is not detected within the preset time period, it indicates that the heating circuit is faulty. Specifically, the value of the preset time period is determined by the size of N, and the larger N is, the larger the preset time period needs to be set.

In summary, the heating fault detection method provided in this embodiment can solve the problem that a conventional heating fault detection circuit needs to add a current transformer or an operational amplifier, and the heating fault detection method provided in this embodiment can determine whether the heating circuit is abnormal at a low cost based on the heating fault detection circuit established in the present application.

Referring to fig. 9, fig. 9 is a schematic flow chart of another embodiment of the heating fault detection method provided in the present application, and the method provided in this embodiment is applied to the heating fault detection circuit provided in any of the above embodiments, as shown in fig. 9, the method provided in this embodiment includes the following steps.

S201: an AC signal is input to a power source terminal.

The ac signal in this embodiment may be the commercial power of 220V, or may also be an ac signal after being processed by processing operations such as filtering, and is not limited in detail herein.

S202: and inputting the first heating control signal or the second heating control signal to a heating control signal end.

Wherein, the second heating control signal has a pulse every NxT/2, N is an even number, and each pulse of the second heating control signal corresponds to the positive half cycle of the AC signal.

S203: and judging whether the heating detection signal output end outputs a heating detection signal or not.

S204: and if so, determining that the heating circuit is normal.

S205: if not, the first heating control signal is input to the heating control signal input end, and whether the heating detection signal is output by the heating detection signal output end or not is judged again.

S206: if so, determining that the heating circuit is normal, otherwise, determining that the heating circuit has a fault.

In this embodiment, the heating fault detection circuit is configured to generate the heating detection signal only when the heating control signal is at a high level, and to generate the heating detection signal only when the negative half cycle of the ac signal is turned on.

Therefore, in order to be able to determine whether an abnormality occurs in the heating circuit, the partial pulse of the heating control signal in the present embodiment must correspond to the negative half cycle of the alternating current signal.

In this embodiment, since the user cannot accurately distinguish whether the first heating control signal or the second heating control signal is input when inputting the heating detection signal, it is necessary to determine whether the first detection signal is input into the heating failure detection circuit according to the output condition of the heating detection signal.

Specifically, if the heating detection signal is detected, it is determined that the first heating control signal is input, and it is determined that the heating circuit does not have any malfunction. If no heating detection signal is detected, there are two possible situations.

The second case is: the second heating control signal is input, and since the heating fault detection method provided by the present embodiment is based on the heating fault detection circuit provided by the above embodiment, the heating fault detection circuit can generate the heating detection signal only when the negative half cycle of the ac signal is turned on when the high level of the input heating control signal is input, and cannot generate the heating detection signal when the positive half cycle of the ac signal is turned on.

If the second condition is satisfied, it is determined that the second heating control signal is input.

At this time, in order to determine whether or not an abnormality occurs in the heating circuit, a heating control signal different from the first input heating control signal, that is, the first heating control signal is input again to the heating failure detection circuit.

Each pulse of the first heating control signal corresponds to the negative half cycle of the alternating current signal, whether a heating detection signal is output or not is judged again, if yes, the heating loop is determined to be normal, and if not, the heating loop is determined to be in fault.

In summary, the heating fault detection circuit provided in this embodiment controls the on/off of the controllable switch through the heating control signal, and according to the characteristics of the heating control signal, the direction of the current flowing through the two ends of the first resistor is affected, and then according to the heating detection signal detected from the heating detection signal output end, whether the heating loop is abnormal or not is determined, so that the heating fault detection circuit provided in this embodiment does not need to add a current transformer or an operational amplifier, and thus the cost can be reduced.

Referring to fig. 10, fig. 10 is a schematic structural diagram of an embodiment of a home appliance provided in the present application. As shown in fig. 10, the household electrical appliance 1000 includes a heating failure detection circuit 100 and a controller 200.

Among them, the heating failure detection circuit 100 is the heating failure detection circuit provided in the above-described embodiment.

The heating failure detection circuit 100 is connected to the controller 200, and the controller 200 is configured to execute the heating failure detection method provided in the foregoing embodiment.

In this embodiment, the household electrical appliance may be an induction cooker, an electric pressure cooker, or the like.

Referring to fig. 11, fig. 11 is a schematic structural diagram of an embodiment of a computer-readable storage medium provided in the present application. As shown in fig. 11, the computer readable storage medium 300 has a computer program 301 stored thereon, and the computer program 301 implements the steps of the heating fault detection method provided by the present application when executed by a processor.

The computer-readable storage medium 300 may be any available media or data storage device that can be accessed by a computer, including but not limited to magnetic memory (optionally floppy disks, hard disks, magnetic tape, magneto-optical disks (MOs), etc.), optical memory (optionally CDs, DVDs, BDs, HVDs, etc.), and semiconductor memory (optionally ROMs, EPROMs, EEPROMs, non-volatile memory 110 (NANDFLASH), solid State Disks (SSDs)), etc.

In summary, the heating fault detection circuit provided in this embodiment controls the controllable switch to be turned on and off according to the heating control signal input from the heating control signal terminal, and further influences the flowing direction of the current flowing through the two ends of the first resistor according to the characteristics of the heating control signal, and further determines whether the heating loop is abnormal according to the detected heating detection signal.

In the several embodiments provided in the present application, it should be understood that the disclosed method and apparatus may be implemented in other manners. Optionally, the above-described apparatus embodiments are only illustrative, and optionally, the division of the above modules or units is only one logical function division, and there may be another division in actual implementation, and optionally, multiple units or components may be combined or may be integrated into another system, or some features may be omitted, or not executed.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the embodiment.

In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units may be integrated into one unit. The integrated unit may be implemented in the form of hardware, or may also be implemented in the form of a software functional unit.

The integrated units in the other embodiments described above may be stored in a computer-readable storage medium if they are implemented in the form of software functional units and sold or used as separate products. Based on such understanding, the technical solution of the present application may be substantially implemented or contributed to by the prior art, or all or part of the technical solution may be embodied in a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, a network device, or the like) or a processor (processor) to execute all or part of the steps of the method according to the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.

The above embodiments are merely examples and are not intended to limit the scope of the present disclosure, and all modifications, equivalents, and flow charts using the contents of the specification and drawings of the present disclosure or those directly or indirectly applied to other related technical fields are intended to be included in the scope of the present disclosure.

Claims

1. A heating fault detection circuit, comprising:

the first end of the controllable switch is connected with a power supply end, and the second end of the controllable switch is connected with a heating end to form a heating loop;

a first end of the first resistor is connected with a second end of the controllable switch;

the control circuit is connected with the second end of the first resistor, the control end of the controllable switch and the heating control signal input end and is used for controlling the conduction of the controllable switch according to the heating control signal input by the heating control signal input end;

the detection circuit is connected with the first end of the first resistor, the second end of the first resistor and the heating detection signal output end and is used for outputting a heating detection signal from the heating detection signal output end according to the current flow direction of the first resistor.

2. The heating fault detection circuit of claim 1,

the control circuit includes:

a first switch circuit connecting the second terminal of the first resistor and the control terminal of the controllable switch;

the second switch circuit is connected with the first switch circuit and the heating control signal input end;

the second switch circuit is turned on in response to the heating control signal being at a preset level, and further controls the first switch circuit to be turned on so as to further control the controllable switch to be turned on.

3. The heating fault detection circuit of claim 2,

the first switching circuit includes:

a first end of the bidirectional optical coupling switch is connected with a second end of the first resistor, and a second end of the bidirectional optical coupling switch is connected with a control end of the controllable switch;

and the anode of the first light-emitting diode is connected with a reference voltage end, and the cathode of the first light-emitting diode is grounded through the second switch circuit.

4. The heating fault detection circuit of claim 3,

the second switching circuit includes:

and the control end of the switch tube is connected with the heating control signal input end, the collector of the switch tube is connected with the cathode of the first light-emitting diode, and the emitter of the switch tube is grounded.

5. The heating fault detection circuit of claim 4,

the first switching circuit further comprises:

a first end of the second resistor is connected with the reference voltage end, and a second end of the second resistor is connected with the anode of the first light-emitting diode; and/or

The second switching circuit further includes:

a first end of the third resistor is connected with the control end of the switching tube, and a second end of the third resistor is connected with the heating control signal input end;

and the first end of the fourth resistor is connected with the control end of the switch tube, and the second end of the fourth resistor is grounded.

6. The heating fault detection circuit of claim 1,

the detection circuit includes:

the anode of the diode is connected with the second end of the first resistor;

the third switch circuit is connected with the cathode of the diode, the first end of the first resistor and the heating detection signal output end;

the third switch circuit is used for being switched on or off according to the current flow direction of the first resistor, so that the heating detection signal is output from the heating detection signal output end.

7. The heating fault detection circuit of claim 6,

the third switching circuit includes:

the anode of the second light-emitting diode is connected with the cathode of the diode, and the cathode of the second light-emitting diode is connected with the first end of the first resistor;

and the collector of the phototriode is connected with the reference voltage end and the heating detection signal output end, and the emitter of the phototriode is grounded.

8. The heating fault detection circuit of claim 7,

the third switching circuit includes:

a fifth resistor, a first end of the fifth resistor being connected to a cathode of the diode, the first resistor and the second resistor being connected to a positive terminal of the diode

The second end of the fifth resistor is connected with the anode of the second light-emitting diode;

a first end of the sixth resistor is connected with the collector of the phototriode, and a second end of the sixth resistor is connected with the reference voltage end;

a first end of the seventh resistor is connected with the collector of the phototriode, and a second end of the seventh resistor is connected with the heating detection signal output end;

and the first end of the capacitor is connected with the collector of the phototriode, and the second end of the capacitor is grounded.

9. A heating failure detection method applied to a heating failure detection circuit according to any one of claims 1 to 8, the heating failure detection method comprising:

providing an alternating current signal to a power supply terminal;

inputting a heating control signal to a heating control signal input end;

acquiring a heating detection signal output by a heating detection signal output end;

and determining the fault condition of the heating loop according to the heating detection signal.

10. The method of claim 9,

the heating control signal is a pulse signal and comprises a plurality of pulses arranged according to a preset time sequence, the starting point of the rising edge of each pulse corresponds to the zero crossing point of the alternating current signal, and at least part of the pulses in the plurality of pulses correspond to the negative half cycle of the alternating current signal.

11. The method of claim 10,

the period of the alternating current signal is T;

the heating control signal has one pulse every NxT/2, and N is an odd number.

12. The method of claim 10,

the period of the alternating current signal is T;

the heating control signal has one pulse every NxT/2, N is an even number, and each pulse corresponds to a negative half cycle of the alternating current signal.

13. The method of claim 12,

the heating control signal comprises a first heating control signal and a second heating control signal;

the first heating control signal has one pulse every NxT/2, N is an even number, and each pulse of the first heating control signal corresponds to the negative half cycle of the alternating current signal;

said second heating control signal has one said pulse every NxT/2, N is an even number, and each said pulse of said second heating control signal corresponds to a positive half cycle of said alternating current signal;

the input of the heating control signal to the heating control signal input terminal includes:

and inputting the second heating control signal to a heating control signal input end, and then inputting the first heating control signal.

14. The method of claim 10,

the period of the alternating current signal is T;

the heating control signal has M consecutive pulses per N x T/2, N being a positive integer greater than 2, M being a positive integer greater than 1 and less than N.

15. An appliance, comprising:

a heating fault detection circuit, the heating fault detection circuit being a heating fault detection circuit as claimed in any one of claims 1-8;

a controller connected to the heating fault detection circuit, the controller being configured to perform the heating fault detection method of any of claims 9-14.