Heating failure detection circuit, heating failure detection method, and home appliance

Abstract

The application discloses a heating fault detection circuit, a heating fault detection method and a household appliance. The heating fault detection circuit comprises a controllable switch, a first end of the controllable switch being connected with a power supply end, a second end of the controllable switch being connected with a heating end to form a heating loop. A first resistor, a first end of the first resistor being connected with the second end of the controllable switch. A control circuit, the control circuit being connected with a second end of the first resistor, a control end of the controllable switch and a heating control signal input end, and being used for controlling the conduction of the controllable switch according to a heating control signal inputted by the heating control signal input end. A detection circuit, the detection circuit being connected with the first end of the first resistor, the second end of the first resistor and a heating detection signal output end, and being used for outputting a heating detection signal from the heating detection signal output end according to the current flowing direction of the first resistor. The fault condition of the heating loop can be detected at low cost.

Description

Technical Field

[0001] The present application relates to the technical field of heating detection, and in particular to a heating fault detection circuit, a heating fault detection method, and a household appliance. Background Art

[0002] A common method for detecting heating current is to collect the circuit current using a current transformer or a small resistor (such as constantan wire or alloy resistor). The magnitude of the current can be used to determine if the heating circuit is abnormal or faulty. In the case of thyristor heating, detecting heating faults does not require measuring the specific heating current value. Using such a detection circuit would require the addition of a current transformer or operational amplifier, which is costly. Summary of the Invention

[0003] The main technical problem solved by the present application is a heating fault detection circuit, a heating fault detection method and a household appliance, which can reduce the cost of the heating fault detection circuit.

[0004] A technical solution adopted in the present application is to provide a heating fault detection circuit, which includes: a controllable switch, wherein the first end of the controllable switch is connected to the power supply end, and the second end of the controllable switch is connected to the heating end to form a heating circuit. A first resistor, wherein the first end of the first resistor is connected to the second end of the controllable switch. A control circuit, wherein the control circuit is connected to the second end of the first resistor, the control end of the controllable switch, and the heating control signal input end, and is used to control the conduction of the controllable switch according to the heating control signal input end. A detection circuit, wherein the detection circuit is connected to the first end of the first resistor, the second end of the first resistor, and the heating detection signal output end, and is used to output a heating detection signal from the heating detection signal output end according to the current flow direction of the first resistor.

[0005] Furthermore, the control circuit includes a first switching circuit connected to the second end of the first resistor and the control end of the controllable switch. A second switching circuit connected to the first switching circuit and the heating control signal input end. The second switching circuit is turned on in response to the heating control signal reaching a preset level, and further controls the first switching circuit to turn on, thereby further controlling the controllable switch to turn on.

[0006] Furthermore, the first switch circuit includes: a bidirectional optocoupler switch, wherein a first end of the bidirectional optocoupler switch is connected to the second end of the first resistor, and a second end of the bidirectional optocoupler switch is connected to the control end of the controllable switch; and a first light-emitting diode, wherein an anode of the first light-emitting diode is connected to a reference voltage end, and a cathode of the first light-emitting diode is grounded via the second switch circuit.

[0007] Furthermore, the second switch circuit includes: a switch tube, a control end of the switch tube is connected to the heating control signal input end, a collector of the switch tube is connected to the cathode of the first light-emitting diode, and an emitter of the switch tube is grounded.

[0008] Furthermore, the first switching circuit further includes: a second resistor, a first end of the second resistor being connected to the reference voltage terminal, and a second end of the second resistor being connected to the anode of the first light-emitting diode. And / or the second switching circuit further includes: a third resistor, a first end of the third resistor being connected to the control terminal of the switching tube, and a second end of the third resistor being connected to the heating control signal input terminal. A fourth resistor, a first end of the fourth resistor being connected to the control terminal of the switching tube, and a second end of the fourth resistor being grounded.

[0009] The detection circuit further includes a diode, the anode of the diode being connected to the second end of the first resistor. A third switch circuit is connected to the cathode of the diode, the first end of the first resistor, and the heating detection signal output terminal. The third switch circuit is configured to be turned on or off based on the current flowing through the first resistor, thereby outputting a heating detection signal from the heating detection signal output terminal.

[0010] Furthermore, the third switch circuit includes: a second light-emitting diode, the anode of the second light-emitting diode being connected to the cathode of the diode, the cathode of the second light-emitting diode being connected to the first end of the first resistor; a phototransistor, the collector of the phototransistor being connected to the reference voltage terminal and the heating detection signal output terminal, and the emitter of the phototransistor being grounded.

[0011] Furthermore, the third switching circuit includes: a fifth resistor, a first end of the fifth resistor being connected to the cathode of the diode, and a second end of the fifth resistor being connected to the anode of the second light-emitting diode; a sixth resistor, a first end of the sixth resistor being connected to the collector of the phototransistor, and a second end of the sixth resistor being connected to the reference voltage terminal; a seventh resistor, a first end of the seventh resistor being connected to the collector of the phototransistor, and a second end of the seventh resistor being connected to the heating detection signal output terminal; and a capacitor, a first end of the capacitor being connected to the collector of the phototransistor, and a second end of the capacitor being grounded.

[0012] To solve the above technical problems, another technical solution adopted in this application is to provide a heating fault detection method. The heating fault detection method is applied to the above heating fault detection circuit. The heating fault detection method includes: providing an AC signal to a power supply terminal; inputting a heating control signal to a heating control signal input terminal; obtaining a heating detection signal output from a heating detection signal output terminal; and determining a heating circuit fault condition based on the heating detection signal.

[0013] To solve the above technical problems, another technical solution adopted in this application is to provide a household appliance, comprising: a heating fault detection circuit, which is the above-mentioned heating fault detection circuit; and a controller, connected to the heating fault detection circuit, configured to execute the above-mentioned heating fault detection method.

[0014] The beneficial effects of the present application are as follows: Different from the prior art, the heating fault detection circuit provided by the present application includes: a controllable switch, wherein the first end of the controllable switch is connected to the power supply end, and the second end of the controllable switch is connected to the heating end to form a heating circuit. A first resistor, wherein the first end of the first resistor is connected to the second end of the controllable switch. A control circuit, wherein the control circuit is connected to the second end of the first resistor, the control end of the controllable switch, and the heating control signal input end, and is used to control the conduction of the controllable switch according to the heating control signal input from the heating control signal input end. A detection circuit, wherein the detection circuit is connected to the first end of the first resistor, the second end of the first resistor, and the heating detection signal output end, and is used to output 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 in this embodiment does not require the addition of a current transformer or an operational amplifier, and thus can detect fault conditions in the heating circuit at a low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without inventive efforts. Among them:

[0016] Figure 1 It is a structural diagram of an embodiment of a heating fault detection circuit provided by the present application;

[0017] Figure 2 is a structural diagram of another embodiment of the heating fault detection circuit provided by the present application;

[0018] Figure 3 This is a structural diagram of another embodiment of the heating fault detection circuit provided by the present application;

[0019] Figure 4 This is a flow chart of an embodiment of a heating fault detection method provided by the present application;

[0020] Figure 5 1 is a signal diagram of an embodiment of an AC signal, a heating control signal, and a heating detection signal when N=1;

[0021] Figure 63 is a signal diagram of an embodiment of an AC signal, a heating control signal and a heating detection signal when N=3;

[0022] FIG7( a ) is a signal diagram of an AC signal, a heating control signal, and a heating detection signal according to an embodiment when N=2;

[0023] FIG7( b ) is a signal diagram of another embodiment of an AC signal, a heating control signal, and a heating detection signal when N=2;

[0024] Figure 8 1 is a signal diagram of an embodiment of an AC signal, a heating control signal, and a heating detection signal when N=4 and M=2;

[0025] Figure 9 This is a flow chart of another embodiment of the heating fault detection method provided by the present application;

[0026] Figure 10 This is a structural diagram of an embodiment of a household appliance provided by the present application;

[0027] Figure 11 It is a structural diagram of an embodiment of a computer-readable storage medium provided by this application. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. It will be understood that the specific embodiments described herein are only used to explain the present application, rather than to limit the present application. It should also be noted that, for ease of description, only some, rather than all, structures related to the present application are shown in the drawings. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0029] The terms "first" and "second" in this application are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of technical features shown. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. A process, method, system, product or device that optionally includes a series of steps or units is not limited to the listed steps or units, but optionally also includes steps or units that are not listed, or optionally also includes other steps or units inherent to these processes, methods, products or devices.

[0030] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0031] Appliances like induction cookers, electric pressure cookers, and rice cookers heat the cookware by utilizing magnetic flux lines generated by a coil, which then cuts through the cookware, generating eddy currents. The Joule heating effect of these eddy currents heats the cookware, thereby heating it. Due to their convenient and fast heating and lack of open flames, induction cookers have become a highly used cooking appliance.

[0032] The heating circuit used to achieve heating in an induction cooker generally includes a resonant circuit and an insulated gate bipolar transistor (IGBT). The induction cooker controls the IGBT to cause the resonant circuit to oscillate, thereby forming a high-frequency, varying current on the coil disk in the resonant circuit, which in turn generates a magnetic field. The magnetic field's magnetic lines of force cut through the cookware to achieve electromagnetic heating (IH). However, in current IH systems, the power transistor IGBT is easily damaged by overcurrent. Therefore, induction cookers on the market generally have a current sampling circuit to monitor the current changes during the operation of the IH device. Currently, commonly used current sampling circuits mainly include mutual inductor current sampling circuits and metal film resistor voltage divider sampling circuits. However, the mutual inductor current sampling circuit requires the use of a mutual inductor for sampling, which is relatively expensive. The metal film resistor voltage divider sampling circuit requires the use of multiple resistors for sampling, which takes up a lot of space and also has relatively high circuit power consumption and heat generation.

[0033] Based on this, this embodiment provides a heating fault detection circuit. The heating fault detection circuit does not require installation of a current transformer or an operational amplifier, and can detect whether a heating circuit is abnormal at a low cost.

[0034] Specifically, see Figure 1 , Figure 1 : is a structural diagram of an embodiment of a heating fault detection circuit provided by the present application, such as Figure 1 As shown, the heating fault detection circuit 100 provided in this embodiment includes a controllable switch 10 , a first resistor 20 , a control circuit 30 and a detection circuit 40 .

[0035] The first end of the controllable switch 10 is connected to the power end AC, and the second end of the controllable switch 10 is connected to the heating end HEAT to form a heating loop.

[0036] In this embodiment, the heating end HEAT is one end connected to the load. The heating fault detection circuit 100 provided in this embodiment is used to connect to the load and heat the load. Optionally, the load can be an induction cooker, an electric pressure cooker, an electric rice cooker or other cookware.

[0037] In this embodiment, if the heating circuit is normal, the heating operation of the load can be realized. Conversely, if the heating circuit is abnormal, the heating operation of the load cannot be realized. Therefore, the heating fault detection circuit 100 provided in this embodiment detects the fault condition of the heating circuit.

[0038] In this embodiment, the controllable switch 10 can be a thyristor switch. Silicon Controlled Rectifier (SCR) is a high-power electrical component, also known as a thyristor, which has the advantages of small size, high efficiency, and long life. The current thyristor structures mainly include full-plane, single-convex, double-convex, etc., and their optimization directions are mainly to reduce high-temperature leakage, improve voltage fluctuation rate, and adjust dynamic current during shutdown. In this embodiment, the thyristor switch can be either a unidirectional thyristor switch or a bidirectional thyristor switch. There are two main ways for thyristor switches to adjust power: drop-wave control and chopping control. Both methods can enable the thyristor to adjust and control the load power.

[0039] The operating principle of a thyristor switch is to control the on-off time ratio of the AC power supply by controlling its conduction angle. In practice, the larger the conduction angle of the thyristor switch, the longer the delay time of the thyristor switch, the smaller the on-off time ratio of the AC power supply, and the smaller the preset power corresponding to this conduction angle. Optionally, the conduction angle of the thyristor switch can be 20°, 30°, or 40°. By controlling the conduction angle, a corresponding preset power can be determined. Of course, the conduction angle of the thyristor switch can also be any other angle, and this is not specifically limited here.

[0040] The second end of the controllable switch 10 is connected to the first end of the first resistor 20 .

[0041] 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, which is used to control the conduction of the controllable switch 10 according to the heating control signal input from the heating control signal input end TRIAC.

[0042] In this embodiment, the control circuit 30 turns on the controllable switch 10 through the input heating control signal, thereby allowing the AC signal to flow to the heating end HEAT through the controllable switch 10 to heat the load such as the induction cooker, electric pressure cooker, and rice cooker.

[0043] The first end of the first resistor 20 , the second end of the first resistor 20 , and the heating detection signal output terminal JNT_HEAT are connected to the detection circuit 40 .

[0044] The detection circuit 40 is configured to output a heating detection signal from the heating detection signal output terminal JNT_HEAT according to the flow direction of the current of the first resistor 20 .

[0045] Specifically, a resistor, namely the first resistor 20 , is connected in series in the driving circuit of the controllable switch 10 , and then the detection circuit 40 is controlled to output a heating detection signal according to the flow direction of the current flowing through the first resistor 10 .

[0046] The current flowing through the first resistor 10 may flow from the first end of the first resistor 10 to the second end of the first resistor 10 , or from the second end of the first resistor 10 to the first end of the first resistor 10 .

[0047] In summary, the heating fault detection circuit provided in this embodiment controls the conduction and closing of the controllable switch through the heating control signal input from the heating control signal input end, thereby affecting the current flow direction of the first resistor, and then judges whether an abnormality occurs in the heating circuit based on the heating detection signal detected from the heating detection signal output end. Therefore, the heating fault detection circuit provided in this embodiment does not require the addition of a current transformer or an operational amplifier, thereby reducing costs.

[0048] Optionally, see also Figure 1 and Figure 2 , Figure 2 3 is a structural diagram of another embodiment of the heating fault detection circuit provided in the present application. As shown in the figure, the control circuit 30 includes a first switch circuit 31 and a second switch circuit 32.

[0049] The second end of the first resistor 20 and the control end of the controllable switch 10 are connected to the first switch circuit 31 .

[0050] The first switch circuit 31 and the heating control signal input terminal TRIAC are connected to the second switch circuit 32 .

[0051] The second switch circuit 32 is turned on in response to the heating control signal being at a preset level, further controlling the first switch circuit 31 to be turned on, thereby further controlling the controllable switch 10 to be turned on. In this embodiment, the heating control signal can be at a high level or a low level.

[0052] The detection circuit 40 includes a diode 42 and a third switch circuit 41 .

[0053] The second end of the first resistor 20 is connected to the anode of the diode 42 .

[0054] 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 switch circuit 41 .

[0055] The third switch circuit 41 is configured to be turned on or off according to the flow direction of the current flowing through both ends of the first resistor 20 , so as to output a heating detection signal from the heating detection signal output terminal JNT_HEAT.

[0056] In this embodiment, a controller such as an MCU can be used to detect whether the heating fault detection circuit 100 outputs a heating detection signal. If so, it indicates that the heating circuit is normal.

[0057] In one embodiment, see also Figure 1 , Figure 2 and Figure 3 , Figure 3 This is a structural diagram of another embodiment of the heating fault detection circuit provided by 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.

[0058] 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 .

[0059] 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 via the second switch circuit 32 .

[0060] The second switching circuit 32 may include a switch 321. The heating control signal input terminal TRIAC is connected to the control terminal of the switch 321. The cathode of the first light-emitting diode 312 is connected to the collector of the switch 321. The emitter of the switch 321 is grounded. The switch 321 is turned on or off according to the preset level of the heating control signal input to its control terminal.

[0061] Optionally, the first switch circuit 31 further includes a second resistor 313 , and the reference voltage terminal V1 is connected to a first end of the second resistor 313 .

[0062] In this embodiment, the second resistor 313 can play a role in voltage division, and the reference voltage end V1 can specifically be 5V.

[0063] An anode of the first light emitting diode 312 is connected to a second end of the second resistor 313 .

[0064] And / or the second switch circuit 32 may further include a third resistor 322 and a fourth resistor 323 .

[0065] The control end of the switch 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 .

[0066] The control end of the switch tube 321 is connected to the first end of the fourth resistor 323 , and the second end of the fourth resistor 323 is grounded.

[0067] The detection circuit 40 includes a diode 42 and a third switch circuit 41 .

[0068] The second end of the first resistor 20 is connected to the anode of the diode 42 .

[0069] 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 switch circuit 41 .

[0070] The third switch circuit 41 is configured to be turned on or off according to the flow direction of the current flowing through both ends of the first resistor 20 , so as to output a heating detection signal from the heating detection signal output terminal JNT_HEAT.

[0071] Specifically, the third switch circuit 41 includes a second light emitting diode 411 and a phototransistor 412 .

[0072] 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 .

[0073] 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.

[0074] 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 .

[0075] 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 .

[0076] The collector of the phototransistor 412 is connected to a first end of the sixth resistor 414 , and the reference voltage terminal V1 is connected to a second end of the sixth resistor 414 .

[0077] The collector of the phototransistor 412 is connected to the first end of the seventh resistor 415 , and the heating detection signal output terminal JNT_HEAT is connected to the second end of the seventh resistor 415 .

[0078] The collector of the phototransistor 412 is connected to a first terminal of the capacitor 416 , and a second terminal of the capacitor 416 is grounded.

[0079] In this embodiment, the working principle of the heating fault detection circuit 100 is:

[0080] When the AC 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 non-conductive, the controllable switch 10 is non-conductive, the voltages across the first resistor 20 are equal, the phototransistor 412 is non-conductive, the heating detection signal output terminal JNT_HEAT remains at a high level, and no heating detection signal is output. In other words, when the heating control signal is at a low level, the heating circuit is non-conductive, and the heating fault detection circuit 100 cannot output a heating detection signal, regardless of whether the heating circuit is operating normally or abnormally.

[0081] When the AC signal crosses zero and the input heating control signal is at a high level, the switch 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 AC signal is turned on, the current flows from the control end of the controllable switch 10 through the bidirectional optocoupler switch 311, the second end of the first resistor 20, and the first end of the first resistor 20 in sequence. Therefore, 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, and the second light-emitting diode 411 is turned on, so that the heating detection signal output terminal JNT_HEAT changes from a high level to a low level, generating a heating detection signal. The microprocessor detects the heating detection signal, indicating that the heating circuit is operating 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, then when the heating circuit is normal, a heating detection signal can be output.

[0082] When the AC signal crosses zero and the input heating control signal is at a high level, the switch 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 positive half-wave of the AC signal is turned on, the current flows from the first end of the first resistor 20, the first resistor 20, the second end of the first resistor 20, the bidirectional optocoupler switch 311, and the control end of the controllable switch 10. Therefore, 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 second light-emitting diode 411 is not turned on, and the heating detection signal output terminal JNT_HEAT will maintain a high level unchanged, and the heating detection signal cannot be generated. The microprocessor cannot detect the heating detection signal and cannot determine whether the heating circuit is working properly. 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, no matter whether the heating circuit is normal or abnormal, the heating detection signal cannot be output.

[0083] In summary, the heating fault detection circuit 100 can only output a heating detection signal when the input heating control signal is at a high level. 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 is not faulty, the heating detection signal output terminal JNT_HEAT can output a heating detection signal. Conversely, if the heating detection signal output terminal JNT_HEAT cannot output a heating detection signal, it indicates that the heating circuit has a fault. When 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 fault detection circuit 100 cannot output a heating detection signal, and at this time, it cannot be determined whether the heating circuit is normal.

[0084] In summary, the heating fault detection circuit provided in this embodiment controls the on and off of the controllable switch through the heating control signal input from the heating control signal end, thereby affecting the current flow direction of the first resistor, and then judges whether an abnormality occurs in the heating circuit based on the heating detection signal detected from the heating detection signal output end. Therefore, the heating fault detection circuit provided in this embodiment does not require the addition of a current transformer or an operational amplifier, thereby reducing costs.

[0085] See Figure 4 , Figure 4 This is a flow chart of an embodiment of a heating fault detection method provided by the present application. The heating fault detection method provided by this embodiment is applied to the heating fault detection circuit provided in any of the above embodiments, such as Figure 4 As shown, the method includes the following steps.

[0086] S101: Input AC signal to the power supply terminal.

[0087] In this embodiment, the AC signal can be 220V mains power, or it can be an AC signal processed by filtering or other processing operations. Optionally, the AC signal can be a sinusoidal signal, or any other AC signal, which is not specifically limited here.

[0088] S102: Inputting a heating control signal to a heating control signal terminal.

[0089] In this embodiment, the heating control signal may be a pulse signal.

[0090] In this embodiment, the heating control signal is used to control the heating process. Specifically, the heating process is controlled by controlling the on or off of a controllable switch of the heating circuit.

[0091] Optionally, the heating control signal may include a plurality of pulses arranged in a preset time sequence, the rising edge starting point of the pulse corresponds to the zero-crossing point of the AC signal, and at least part of the pulses corresponds to the negative half cycle of the AC signal.

[0092] It is understood that the heating fault detection method provided in this embodiment is based on the heating fault detection circuit provided in the above-described embodiment. Furthermore, when the input heating control signal is at a high level, the heating fault detection circuit must conduct the negative half-cycle of the AC signal to generate a heating detection signal. When conducting the positive half-cycle of the AC signal, no heating detection signal is generated. In this case, even if the heating circuit is functioning properly, it is impossible to determine whether the heating circuit has a fault. Therefore, in this embodiment, some pulses of the heating control signal must correspond to the negative half-cycle of the AC signal.

[0093] In a specific embodiment, let the period of the AC signal be T, and the heating control signal has a pulse every N*T / 2, where N is an odd number. Figure 5 , Figure 5 1 is a signal diagram of an embodiment of an AC signal, a heating control signal, and a heating detection signal when N=1. Figure 5 As shown, each negative half-cycle of the AC signal is turned on by the heating control signal, and the heating fault detection circuit outputs a 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. Conversely, if the heating detection signal is not detected within the preset time period, it indicates that the heating circuit has a fault. Since the heating monitoring signal output terminal outputs a heating detection signal every T, the preset time period can be T or greater than T.

[0094] In one embodiment, when N=3, see Figure 6 , Figure 6 FIG. 1 is a signal diagram of an embodiment of an AC signal, a heating control signal, and a heating detection signal when N=3. Figure 6 As shown, the heating control signal alternately conducts the positive and negative half-cycles of the AC signal, and the heating fault detection circuit outputs a 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. Conversely, if the heating detection signal is not detected within the preset time period, it indicates that the heating circuit has a fault. Since the heating detection signal output terminal outputs a heating detection signal every 3T, the preset time period can be 3T or greater.

[0095] In another embodiment, the period of the AC signal is still assumed to be T. In this embodiment, the heating control signal has a pulse every N*T / 2, where N is an even number, and each pulse corresponds to the negative half cycle of the AC signal.

[0096] Specifically, when N is an even number, the heating control signal may be turned on during the entire positive half-cycle of the AC signal, or during the entire negative half-cycle of the AC signal. In this embodiment, N=2 is used as an example for illustrative description. Referring to FIG7(a), FIG7(a) is a signal schematic diagram of an embodiment of the AC signal, the heating control signal, and the heating detection signal when N=2. As shown in FIG7(a), the heating detection signal is turned on during the entire negative half-cycle of the AC signal. At this time, the heating fault detection circuit outputs a heating detection signal every T. Referring to FIG7(b), FIG7(a) is a signal schematic diagram of another embodiment of the AC signal, the heating control signal, and the heating detection signal when N=2. As shown in FIG7(b), the heating detection signal is turned on during the entire positive half-cycle of the AC signal. In this case, even if the heating circuit is normal, the heating fault detection circuit will not output a heating detection signal.

[0097] Therefore, in this embodiment, each pulse of the heating control signal is set to correspond to the negative half cycle of the AC signal to ensure that the heating fault detection method provided in this embodiment can detect the fault condition of the heating circuit.

[0098] Optionally, each pulse may be made to correspond to the negative half cycle of the AC signal in the following manner to prevent failure in detecting a fault condition of the heating circuit.

[0099] Specifically, the heating control signal includes a first heating control signal and a second heating control signal.

[0100] The first heating control signal has a pulse every N*T / 2, N is an even number, and each pulse of the first heating control signal corresponds to a negative half cycle of the AC signal.

[0101] The second heating control signal has a pulse every N*T / 2, N is an even number, and each pulse of the second heating control signal corresponds to a positive half cycle of the AC signal.

[0102] Optionally, step S102 may specifically be:

[0103] The second heating control signal is input first, and then the first heating control signal is input.

[0104] In this embodiment, if the second heating control signal is input first, it is impossible to detect whether the heating circuit is normal.

[0105] At this time, the first heating control signal can be input. If the heating circuit is normal, a heating detection signal can be generated. If no heating detection signal is collected, there are two possible situations.

[0106] The first situation is that the first heating control signal is input, but due to a failure in the heating circuit, no heating detection signal is output.

[0107] The second situation is: the second heating control signal is input. If it is the second situation, in order to judge the fault condition of the heating circuit, a heating control signal different from the first input heating control signal, that is, the first heating control signal, is input into the heating fault detection circuit again. Since each pulse of a heating control signal corresponds to the negative half cycle of the AC signal, it is judged again whether a heating detection signal is output. If so, it is determined that the heating circuit is normal. If not, it is determined that the heating circuit has a fault.

[0108] Specifically, if the second heating control signal is input, the time when the first heating control signal is input may vary depending on N. Optionally, when N is 2, if the first heating control signal is input and the heating circuit is normal, the heating fault detection circuit should output a heating detection signal every T. Therefore, if no heating detection signal is collected within a preset time period, it indicates that the second heating control signal is input.

[0109] At this time, the first heating control signal is input, and the preset time period must be at least 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, it indicates that the heating circuit has failed. Optionally, when N = 4, the time for inputting the first heating control signal must be greater than 2T, when N = 6, the time must be greater than 3T, ..., when N is 2K, the time must be greater than KT, where K is a positive integer. In this embodiment, the heating fault detection circuit is determined twice to determine whether to output the heating detection signal to further determine whether the heating circuit is operating normally.

[0110] In another specific implementation, the period of the AC signal is still assumed to be T.

[0111] In this embodiment, the heating control signal has M consecutive pulses every N*T / 2.

[0112] In this embodiment, N is a positive integer greater than 2, and M is a positive integer greater than 1 and smaller than N.

[0113] In this embodiment, since M is a positive integer equal to 1, it can be understood that two or more consecutive pulses can conduct at least two consecutive half-cycles of the AC signal. According to the characteristics of the AC signal, if the AC signal is a sinusoidal AC signal, the sinusoidal AC signal has a signal characteristic of alternating positive and negative half-cycles, and these at least two half-cycles include at least one negative half-cycle. Optionally, every two consecutive half-cycles of the sinusoidal AC signal include a negative half-cycle, and every three consecutive half-cycles of the sinusoidal AC signal may include one negative half-cycle or two negative half-cycles. When the negative half-cycle of the AC signal is conducted, if the heating circuit is not faulty, a heating detection signal can be output. That is, if the heating detection signal can be detected, it indicates that the heating circuit is not faulty. Conversely, if the heating detection signal output terminal does not detect the heating detection signal within a preset time period, it indicates that the heating circuit is faulty.

[0114] See Figure 8 , Figure 8 : is a signal diagram of an embodiment of an AC signal, a heating control signal and a heating detection signal when N=4 and M=2. Figure 8 As shown, when N = 4 and M = 2, it means that the heating control signal has two consecutive pulses every 2T. At this time, the two consecutive pulses can conduct the positive half-cycle and negative half-cycle of the AC signal. Therefore, when the heating circuit is normal, the circuit can output a heating detection signal every 2T. In other words, if the heating detection signal can be detected within the preset time period, it indicates that the heating circuit is not faulty. Conversely, if the heating detection signal output terminal does not detect the heating detection signal within the preset time period, it indicates that the heating circuit has a fault. In this embodiment, the preset time period can be adaptively adjusted according to the size of N. Specifically, the preset time period increases as N increases. In one specific embodiment, when N = 4, the preset time period can be greater than or equal to 2T.

[0115] S103: Acquire a heating detection signal outputted from a heating detection signal output terminal.

[0116] In this embodiment, depending on the type of heating control signal, the heating detection signal output terminal may output a heating detection signal, which indicates that the heating circuit is normal. However, if the heating detection signal output terminal does not output a heating detection signal, it does not indicate that the heating circuit is abnormal. In this case, it is necessary to determine whether the heating circuit is abnormal based on the specific type of heating control signal. Specifically, depending on the specific type of heating control signal, if no heating detection signal is output, it is either because the heating circuit is abnormal or because the heating control signal conducts the positive half-cycle of the AC signal, preventing the detection circuit from outputting a heating detection signal, and therefore it is impossible to determine whether the heating circuit is abnormal.

[0117] S104: Determine the fault condition of the heating circuit according to the heating detection signal.

[0118] In one embodiment, the AC signal has a period of 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 a pulse every T / 2, when N=3, the heating control signal has a pulse every 3T / 2, and so on.

[0119] At this time, if the heating detection signal can be detected within the preset time, it indicates that the heating circuit is normal. Conversely, if the heating detection signal is not detected within the preset time period, it indicates that the heating circuit has a fault.

[0120] Optionally, in this embodiment, the preset time period increases as N increases. Optionally, when N is 1, the preset time period may be a value greater than or equal to T. When N is 3, the preset time period may be a value greater than or equal to 3T.

[0121] In one embodiment, the AC signal has a period of T. In this embodiment, the heating control signal has a pulse every N*T / 2, where 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 a pulse every T; when N=4, the heating control signal has a pulse every 2T, and so on.

[0122] At this time, if the heating detection signal can be detected within the preset time, it indicates that the heating circuit is normal. Conversely, if the heating detection signal is not detected within the preset time period, it indicates that the heating circuit has a fault. The preset time period increases as N increases. Optionally, when N is 2, the preset time period can be a value greater than or equal to T. When N is 4, the preset time period can be a value greater than or equal to 2T.

[0123] In a specific embodiment, the heating control signal includes a first heating control signal and a second heating control signal.

[0124] The first heating control signal has a pulse every N*T / 2, N is an even number, and each pulse of the first heating control signal corresponds to a negative half cycle of the AC signal.

[0125] The second heating control signal has a pulse every N*T / 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. The heating control signal input to the heating control signal input terminal can be specifically:

[0126] The second heating control signal is input first, and then the first heating control signal is input.

[0127] Specifically, the second heating control signal is input first. If no heating detection signal is detected within the preset time period, the first heating control signal is input again, and it is determined again whether the heating detection signal is detected. Then, whether the heating circuit is abnormal is determined based on the heating detection signal detected within the preset time period.

[0128] Specifically, the value of the preset time period is determined by the value of N.

[0129] In a specific embodiment, the heating control signal has M consecutive pulses every N*T / 2, where N is a positive integer greater than 2, and M is a positive integer greater than 1 and less than N. For example, when N=3 and M=2, the heating control signal has two pulses every 3T / 2, when N=4 and M=2, the heating control signal has two pulses every 2T, and so on.

[0130] At this time, if the heating detection signal can be detected within the preset time period, it indicates that the heating circuit is normal. Conversely, if the heating detection signal is not detected within the preset time period, it indicates that the heating circuit has a fault. Specifically, the value of the preset time period is determined by the value of N. The larger N is, the longer the preset time period should be set.

[0131] In summary, the heating fault detection method provided in this embodiment can solve the cost burden brought by the need to add current transformers or operational amplifiers in traditional heating fault detection circuits, and the heating fault detection method provided in this embodiment is based on the heating fault detection circuit established in this application, which can realize low-cost judgment of whether an abnormality occurs in the heating circuit.

[0132] See Figure 9 , Figure 9 This is a flow chart of another embodiment of the heating fault detection method provided by the present application. The method provided in this embodiment is applied to the heating fault detection circuit provided in any of the above embodiments, such as Figure 9 As shown, the method provided in this embodiment includes the following steps.

[0133] S201: Input an AC signal to the power supply terminal.

[0134] The AC signal in this embodiment may be 220V mains electricity, or may be an AC signal that has been processed by filtering or other processing operations, which is not specifically limited here.

[0135] S202: Inputting the first heating control signal or the second heating control signal to the heating control signal terminal.

[0136] The first heating control signal has a pulse every N*T / 2, N is an even number, and each pulse of the first heating control signal corresponds to a negative half cycle of the AC signal.

[0137] The second heating control signal has a pulse every N*T / 2, N is an even number, and each pulse of the second heating control signal corresponds to a positive half cycle of the AC signal.

[0138] S203: Determine whether the heating detection signal output terminal outputs a heating detection signal.

[0139] S204: If yes, determine that the heating circuit is normal.

[0140] S205: If not, input the first heating control signal to the heating control signal input terminal, and again determine whether the heating detection signal output terminal outputs a heating detection signal.

[0141] S206: If yes, it is determined that the heating circuit is normal; otherwise, it is determined that the heating circuit is faulty.

[0142] In this embodiment, when the input heating control signal is at a high level, the heating fault detection circuit must conduct the negative half cycle of the AC signal to generate a heating detection signal. When the positive half cycle of the AC signal is conducted, the heating detection signal cannot be generated, and at this time it is impossible to determine whether the heating circuit has a fault.

[0143] Therefore, in order to determine whether an abnormality occurs in the heating circuit, some pulses of the heating control signal in this embodiment must correspond to the negative half cycle of the AC signal.

[0144] In this embodiment, since the user cannot accurately distinguish whether the input is the first heating control signal or the second heating control signal when inputting the heating detection signal, it is necessary to determine whether the input to the heating fault detection circuit is the first detection signal based on the output of the heating detection signal.

[0145] Specifically, if the heating detection signal is detected, it is determined that the input is the first heating control signal, and it is determined that the heating circuit has no faults. If the heating detection signal is not detected, there are two possible situations.

[0146] The first situation is that the first heating control signal is input, but due to a failure in the heating circuit, no heating detection signal is output.

[0147] The second situation is: the input is the second heating control signal. Since the heating fault detection method provided in this embodiment is based on the heating fault detection circuit provided in the above embodiment, and the heating fault detection circuit must conduct the negative half cycle of the AC signal to generate a heating detection signal when the input heating control signal is high, and cannot generate a heating detection signal when the positive half cycle of the AC signal is conducted.

[0148] If it is the second case, it is determined that the input is the second heating control signal.

[0149] At this time, in order to determine whether an abnormality occurs in the heating circuit, a heating control signal different from the first heating control signal input, that is, the first heating control signal, is input again into the heating fault detection circuit.

[0150] Since each pulse of the first heating control signal corresponds to the negative half cycle of the AC signal, it is determined again whether a heating detection signal is output. If so, it is determined that the heating circuit is normal. If not, it is determined that the heating circuit is faulty.

[0151] In summary, the heating fault detection circuit provided in this embodiment controls the conduction and closing of the controllable switch through the heating control signal, and affects the direction of the current flowing through the two ends of the first resistor according to the characteristics of the heating control signal, and then judges whether an abnormality occurs in the heating circuit based on the heating detection signal detected from the heating detection signal output end. Therefore, the heating fault detection circuit provided in this embodiment does not require the addition of a current transformer or an operational amplifier, thereby reducing costs.

[0152] See Figure 10 , Figure 10 This is a schematic diagram of the structure of an embodiment of the household appliance provided by this application. Figure 10 As shown, the household appliance 1000 includes a heating fault detection circuit 100 and a controller 200 .

[0153] The heating fault detection circuit 100 is the heating fault detection circuit provided in the above embodiment.

[0154] The heating fault detection circuit 100 is connected to the controller 200 , and the controller 200 is used to execute the heating fault detection method provided in the above embodiment.

[0155] In this embodiment, the household appliance may be an induction cooker, an electric rice cooker, an electric pressure cooker, and the like.

[0156] See Figure 11 , Figure 11 This is a schematic diagram of the structure of an embodiment of a computer-readable storage medium provided by this application. Figure 11 As shown, the computer-readable storage medium 300 stores a computer program 301 , and when the computer program 301 is executed by a processor, the steps of the heating fault detection method provided in the present application are implemented.

[0157] The computer-readable storage medium 300 can be any available medium or data storage device that can be accessed by a computer, including but not limited to magnetic storage (optionally floppy disks, hard disks, magnetic tapes, magneto-optical disks (MO), etc.), optical storage (optionally CDs, DVDs, BDs, HVDs, etc.), and semiconductor storage (optionally ROMs, EPROMs, EEPROMs, non-volatile memory 110 (NANDFLASH), solid-state drives (SSDs)), etc.

[0158] In summary, the heating fault detection circuit provided in this embodiment controls the conduction and closing of the controllable switch through the heating control signal input from the heating control signal end, and then affects the flow direction of the current flowing through the two ends of the first resistor according to the characteristics of the heating control signal, and then judges whether the heating circuit has an abnormality based on the detected heating detection signal. Therefore, the heating fault detection circuit provided in this embodiment does not require the addition of a current transformer or an operational amplifier, thereby reducing costs.

[0159] In the several embodiments provided in this application, it should be understood that the disclosed methods and devices can be implemented in other ways. Optionally, the device embodiments described above are merely illustrative. Optionally, the division of the modules or units described above is merely a logical functional division. In actual implementation, there may be other division methods. Optionally, multiple units or components may be combined or integrated into another system, or some features may be ignored or not performed.

[0160] The units described above as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected according to actual needs to achieve the purpose of this embodiment.

[0161] In addition, each functional unit in each embodiment of the present application may be integrated into a processing unit, each unit may exist physically separately, or two or more units may be integrated into a single unit. The above-mentioned integrated units may be implemented in the form of hardware or software functional units.

[0162] If the integrated units in the above other embodiments are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) or a processor to execute all or part of the steps of the various implementation methods of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0163] The above is only an implementation method of the present application and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the description and drawings of this application, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A heating fault detection circuit, characterized in that: The heating fault detection circuit comprises: A controllable switch, wherein a first end of the controllable switch is connected to a power supply end, and a second end of the controllable switch is connected to a heating end, so as to form a heating circuit; the controllable switch is a bidirectional thyristor switch; a first resistor, wherein a first end of the first resistor is connected to the second end of the controllable switch; a control circuit connected to the second end of the first resistor, the control end of the controllable switch, and the heating control signal input end, and configured to control conduction of the controllable switch according to a heating control signal inputted from the heating control signal input end; A detection circuit is connected to the first end of the first resistor, the second end of the first resistor, and the heating detection signal output end, and is used to output 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 according to claim 1, characterized in that: The control circuit comprises: a first switch circuit, the first switch circuit connecting the second end of the first resistor and the control end of the controllable switch; a second switch circuit, connecting the first switch circuit and the heating control signal input terminal; 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 according to claim 2, characterized in that: The first switching circuit includes: a bidirectional optocoupler switch, wherein a first end of the bidirectional optocoupler switch is connected to the second end of the first resistor, and a second end of the bidirectional optocoupler switch is connected to the control end of the controllable switch; A first light emitting diode, wherein the anode of the first light emitting diode is connected to the reference voltage terminal, and the cathode of the first light emitting diode is grounded through the second switch circuit.

4. The heating fault detection circuit according to claim 3, characterized in that: The second switching circuit includes: A switch tube, wherein the control end of the switch tube is connected to the heating control signal input end, the collector of the switch tube is connected to the cathode of the first light-emitting diode, and the emitter of the switch tube is grounded.

5. The heating fault detection circuit according to claim 4, characterized in that: The first switch circuit further includes: a second resistor, wherein a first end of the second resistor is connected to the reference voltage end, and a second end of the second resistor is connected to the anode of the first light-emitting diode; and / or The second switch circuit further includes: a third resistor, wherein a first end of the third resistor is connected to the control end of the switch tube, and a second end of the third resistor is connected to the heating control signal input end; a fourth resistor, wherein a first end of the fourth resistor is connected to the control end of the switch tube, and a second end of the fourth resistor is grounded.

6. The heating fault detection circuit according to claim 1, characterized in that: The detection circuit comprises: a diode, wherein an anode of the diode is connected to the second end of the first resistor; a third switch circuit connected to the cathode of the diode, the first end of the first resistor, and the heating detection signal output end; The third switch circuit is configured to be turned on or off according to the current flowing through the first resistor, so as to output the heating detection signal from the heating detection signal output terminal.

7. The heating fault detection circuit according to claim 6, characterized in that: The third switch circuit includes: a second light-emitting diode, wherein the anode of the second light-emitting diode is connected to the cathode of the diode, and the cathode of the second light-emitting diode is connected to the first end of the first resistor; A phototransistor, wherein the collector of the phototransistor is connected to the reference voltage terminal and the heating detection signal output terminal, and the emitter of the phototransistor is grounded.

8. The heating failure detection circuit according to claim 7, characterized in that: The third switch circuit includes: a fifth resistor, wherein a first end of the fifth resistor is connected to the cathode of the diode, and a second end of the fifth resistor is connected to the anode of the second light-emitting diode; a sixth resistor, wherein a first end of the sixth resistor is connected to the collector of the phototransistor, and a second end of the sixth resistor is connected to the reference voltage terminal; a seventh resistor, wherein a first end of the seventh resistor is connected to the collector of the phototransistor, and a second end of the seventh resistor is connected to the heating detection signal output end; A capacitor, wherein a first end of the capacitor is connected to the collector of the phototransistor, and a second end of the capacitor is grounded.

9. A heating fault detection method, characterized in that: The heating fault detection method is applied to the heating fault detection circuit according to any one of claims 1 to 8, and the heating fault detection method includes: Provide AC signal to the power supply end; Inputting a heating control signal to the heating control signal input terminal; wherein at least some of the multiple pulses in the heating control signal correspond to the negative half cycle of the AC signal; Obtaining a heating detection signal outputted by a heating detection signal output terminal; A fault condition of the heating circuit is determined based on the heating detection signal.

10. The method according to claim 9, characterized in that The heating control signal is a pulse signal, including a plurality of pulses arranged in a preset time sequence, and the rising edge starting point of the pulse corresponds to the zero-crossing point of the AC signal.

11. The method according to claim 10, characterized in that The period of the AC signal is T; The heating control signal has a pulse every N*T / 2, where N is an odd number.

12. The method according to claim 10, characterized in that The period of the AC signal is T; The heating control signal has a pulse every N*T / 2, where N is an even number, and each pulse corresponds to a negative half cycle of the AC signal.

13. The method according to claim 12, characterized in that The heating control signal includes a first heating control signal and a second heating control signal; The first heating control signal has a pulse every N*T / 2, where N is an even number, and each pulse of the first heating control signal corresponds to a negative half cycle of the AC signal; The second heating control signal has one pulse every N*T / 2, where N is an even number, and each pulse of the second heating control signal corresponds to a positive half cycle of the AC signal; The step of inputting a heating control signal to the heating control signal input terminal comprises: The second heating control signal is first input into the heating control signal input terminal, and then the first heating control signal is input.

14. The method according to claim 10, characterized in that The period of the AC signal is T; The heating control signal has M consecutive pulses every N*T / 2, where N is a positive integer greater than 2, and M is a positive integer greater than 1 and smaller than N.

15. A household appliance, characterized in that: The household appliances include: A heating fault detection circuit, wherein the heating fault detection circuit is the heating fault detection circuit according to any one of claims 1 to 8; A controller is connected to the heating fault detection circuit, and the controller is used to execute the heating fault detection method according to any one of claims 9 to 14.

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