Detection circuit, cooking utensil and detection device

Abstract

The utility model discloses a detection circuit, a cooking utensil and a detection device. The detection circuit is used for detecting an electric component driven by direct current and comprises a detection interface, a current transformer, at least one shunt branch and a current acquisition circuit. The detection interface is used for being connected in series with a direct current bus of an electric component driven by direct current; a primary coil of the current transformer is connected in series with the detection interface; the shunt branch is connected with the detection interface in series and is connected with a primary coil of the current transformer in parallel, the shunt branch comprises a voltage stabilizing diode, an anode of the voltage stabilizing diode is connected to a cathode of the direct current bus, and a cathode of the voltage stabilizing diode is connected to an anode of the direct current bus; the current acquisition circuit is connected to a secondary coil of the current transformer and is used for acquiring current signals in the secondary coil.

Description

Technical Field

[0001] The present application relates to the technical field of detection equipment, and in particular to a detection circuit for detecting electrical components driven by direct current, as well as a cooking appliance and a detection device having the detection circuit. Background Art

[0002] Existing household appliances need to detect current signals to determine whether they can work normally, that is, whether there is power output. To detect the current signal, sampling is required, which is generally done by directly sampling with a resistor or sampling using the electromagnetic induction principle of an inductor. When sampling with a resistor, the temperature will be very high when the current is large. Inductor sampling can only sample alternating current, and alternating current can only be in the main current loop, which will make installation inconvenient and the volume larger.

[0003] Therefore, a detection circuit for detecting a DC-driven electrical component is needed to at least partially solve the above problems. Utility Model Content

[0004] A series of simplified concepts are introduced in the utility model content section, which will be further described in detail in the detailed implementation section. The utility model content section of this application does not mean to attempt to define the key features and essential technical features of the technical solution claimed for protection, nor does it mean to attempt to determine the scope of protection of the technical solution claimed for protection.

[0005] In order to at least partially solve the above problems, the first aspect of the present application provides a detection circuit for detecting a DC-driven electrical component, characterized in that the detection circuit comprises:

[0006] A detection interface, used to be connected in series with a DC bus of the DC-driven electrical component;

[0007] A current transformer, wherein the primary coil of the current transformer is connected in series with the detection interface;

[0008] at least one shunt branch, the shunt branch being connected in series with the detection interface and in parallel with the primary coil of the current transformer, the shunt branch comprising a switch module, the switch module being configured to conduct current; and

[0009] A current acquisition circuit is connected to the secondary coil of the current transformer and is used to acquire a current signal in the secondary coil.

[0010] According to the present application, after the electrical components are powered on, the current in the DC bus gradually increases. The shunt branch and the primary coil of the current transformer shunt the current in the DC bus. Since the primary coil flows with direct current, the current in the secondary coil changes very little. When the current in the DC bus increases to a certain extent, the current in the shunt branch also increases, so that the switch module is turned on. After the switch module is turned on, the current in the shunt branch will increase rapidly, causing the current in the primary coil to decrease rapidly. Corresponding to the primary coil, when the current suddenly changes, under the action of electromagnetic induction, the current in the secondary coil will produce a pulse (mutation). Thus, it is possible to determine whether the electrical components can work normally by detecting whether there is a pulse current in the secondary coil. The present application adopts a voltage-stabilizing diode breakdown shunt, so that the detection circuit design is simple and low in cost. By selecting a current transformer with a suitable input-output ratio, the current output by the secondary coil can be made smaller, so that the detection resistor generates less heat. In addition, the detection circuit is not directly connected to the AC power supply, which is more convenient to install.

[0011] Optionally, the switch module is configured as a Zener diode, an anode of the Zener diode is connected to the negative electrode of the DC bus, and a cathode of the Zener diode is connected to the positive electrode of the DC bus.

[0012] According to the present application, the switch module has low cost and stable performance. When the current in the DC bus increases to a certain extent, the current in the shunt branch also increases, causing the voltage regulator diode to be reversely broken down by the current. After the breakdown, the current in the shunt branch will increase rapidly, causing the current in the primary coil to decrease rapidly.

[0013] Optionally, the shunt branch further includes a current limiting resistor, and the current limiting resistor is connected in series with the voltage stabilizing diode.

[0014] According to the present application, the current limiting resistor is used to protect the voltage zener diode so that the current flowing through the voltage zener diode does not exceed the limit value, so that the voltage zener diode can recover.

[0015] Optionally, there are multiple shunt branches, and the reverse breakdown currents of the Zener diodes in different shunt branches are different.

[0016] According to the present application, when the current of the electrical component gradually increases, multiple voltage regulator diodes are reversely broken down in sequence, indicating that the current is gradually increasing. Thus, the detection circuit can be used to detect electrical components with different working currents.

[0017] Optionally, the reverse breakdown voltages of the Zener diodes in different shunt branches are different, the reverse breakdown voltage of the Zener diode with a larger reverse breakdown current is larger, and the reverse breakdown voltage of the Zener diode with a smaller reverse breakdown current is smaller.

[0018] According to the present application, the reverse breakdown voltages of the zener diodes are different, which can further ensure that the zener diodes are broken down in sequence to adapt to the gradual increase of the current in the DC bus. Thus, the detection circuit can be applied to detect electrical components with different working currents.

[0019] Optionally, the resistance values ​​of the current limiting resistors in different shunt branches are different, the resistance value of the current limiting resistor connected in series with the voltage zener diode with a larger reverse breakdown current is smaller, and the resistance value of the current limiting resistor connected in series with the voltage zener diode with a smaller reverse breakdown current is larger.

[0020] According to the present application, the resistance of the current limiting resistor matches the performance of the voltage-stabilizing diode, so that the voltage-stabilizing diode can recover after breakdown.

[0021] Optionally, there are multiple shunt branches, and the conduction currents of the switch modules in different shunt branches are different.

[0022] According to the present application, when the current of the electrical component gradually increases, multiple switch modules are turned on in sequence, indicating that the current is gradually increasing. Thus, the detection circuit can be used to detect electrical components with different working currents.

[0023] Optionally, the current acquisition circuit is connected in series with the secondary coil of the current transformer, and the current acquisition circuit includes a plurality of detection resistors connected in series.

[0024] According to the present application, the current acquisition circuit adopts a resistor voltage division design, and detects the current by detecting the voltage, which has obvious effect and stable performance.

[0025] Optionally, the current acquisition circuit further includes a filter capacitor, and the filter capacitor is connected in parallel with the detection resistor among the multiple detection resistors connected to the negative electrode of the secondary coil.

[0026] According to the present application, the filter capacitor can filter out high-frequency interference and clutter in the current acquisition circuit, making the detection result more accurate.

[0027] A second aspect of the present application provides a cooking utensil, characterized in that it comprises:

[0028] Electrical components driven by direct current;

[0029] The detection circuit according to any one of the first aspects, wherein the detection interface is used to be connected in series with a DC bus of the electrical component; and

[0030] A selective connection element is provided, wherein the selective connection element has a first connection state and a second connection state, and is used to electrically decouple the electrical component from the detection circuit in the first connection state, and to connect the electrical component and the detection circuit in series in the second connection state.

[0031] According to the present application, the cooking appliance has a built-in detection circuit, so that detection is more convenient. The state of the selected connection element determines whether the electrical component is working normally or under inspection.

[0032] Optionally, the selection connection element is configured as a short-circuit terminal or a single-pole double-throw switch.

[0033] Depending on the application, the connection elements can be flexibly configured.

[0034] Optionally, the electrical component is configured as a motor, a relay, or an electromagnetic oscillation coil.

[0035] According to the present application, the detection circuit can detect various DC power-consuming components of the cooking appliance.

[0036] A third aspect of the present application provides a detection device for detecting electrical components driven by direct current, wherein the detection device comprises a detection circuit according to any one of the first aspects.

[0037] According to the present application, after the electrical components are powered on, the current in the DC bus gradually increases. The shunt branch and the primary coil of the current transformer shunt the current in the DC bus. Since the primary coil flows with direct current, the current in the secondary coil changes very little. When the current in the DC bus increases to a certain extent, the current in the shunt branch also increases, so that the switch module is turned on. After the switch module is turned on, the current in the shunt branch will increase rapidly, causing the current in the primary coil to decrease rapidly. Corresponding to the primary coil, when the current suddenly changes, under the action of electromagnetic induction, the current in the secondary coil will produce a pulse (mutation). Thus, it is possible to determine whether the electrical components can work normally by detecting whether there is a pulse current in the secondary coil. The present application adopts a voltage-stabilizing diode breakdown shunt, so that the detection circuit design is simple and low in cost. By selecting a current transformer with a suitable input-output ratio, the current output by the secondary coil can be made smaller, so that the detection resistor generates less heat. In addition, the detection circuit is not directly connected to the AC power supply, which is more convenient to install. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The following drawings of the present application are used as a part of the present application for understanding the present application. The drawings show representative embodiments of the present application and are used to explain the principle of the present application, rather than to limit the present application.

[0039] In the attached figure:

[0040] Figure 1 A schematic diagram of a circuit principle for detecting a DC-driven electrical component according to a detection circuit of a preferred embodiment of the present application;

[0041] Figure 2 for Figure 1 A timing diagram of a detection signal of the detection circuit shown;

[0042] Figure 3 A partial circuit diagram of a cooking appliance according to the first embodiment of the present application;

[0043] Figure 4 It is a partial circuit diagram of a cooking appliance according to the second embodiment of the present application.

[0044] Description of reference numerals:

[0045] 10: Diversion branch

[0046] 11: Switching module / Zener diode

[0047] 12: Current limiting resistor

[0048] 20: Current acquisition circuit

[0049] 21: Public terminal

[0050] 30: Analysis module

[0051] 40: Detection interface

[0052] 100: Cooking Utensils

[0053] 110: Electrical components

[0054] 101: DC Power Supply

[0055] 102: DC bus

[0056] 120: Select connection element

[0057] 121: Immobile end

[0058] 122: First free end

[0059] 123: Second free end DETAILED DESCRIPTION

[0060] In the following description, a large number of specific details are provided to provide a more thorough understanding of the present application. However, it is apparent to those skilled in the art that the present application can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present application, some technical features well known in the art are not described.

[0061] In order to thoroughly understand the present application, a detailed description will be provided in the following description. It should be understood that these embodiments are provided to make the disclosure of the present application thorough and complete, and to fully convey the concepts of these exemplary embodiments to those of ordinary skill in the art. Obviously, the implementation of the embodiments of the present application is not limited to the specific details familiar to those skilled in the art. The preferred embodiments of the present application are described in detail below, but in addition to these detailed descriptions, the present application may also have other embodiments.

[0062] Ordinal numbers such as "first" and "second" cited in this application are merely identifiers and do not have any other meaning, such as a specific order, etc. Moreover, for example, the term "first component" itself does not imply the existence of a "second component", and the term "second component" itself does not imply the existence of a "first component". The use of the words "first", "second", and "third" does not indicate any order, and these words can be interpreted as names.

[0063] It should be noted that the terms "upper", "lower", "front", "back", "left", "right", "inside", "outside" and similar expressions used in this application are for illustrative purposes only and are not limiting.

[0064] In this document, “equal”, “same”, etc. are not strictly limited in a mathematical and / or geometric sense, but also include errors that can be understood by those skilled in the art and are allowed in manufacturing or use.

[0065] Unless otherwise stated, the numerical ranges herein include not only the entire range within its two endpoints but also include several sub-ranges contained therein.

[0066] The present application provides a detection circuit for detecting an electrical component driven by direct current, as well as a cooking appliance and a detection device having the detection circuit.

[0067] Now, exemplary embodiments according to the present application will be described in more detail with reference to the accompanying drawings.

[0068] like Figure 1 As shown, in a specific embodiment, the detection circuit 200 for detecting the DC-driven electrical component according to the present application is used to detect the performance (whether it can work normally) of the electrical component 110. It can be understood that the electrical component 110 is driven by DC power, for example, driven by a DC power supply 101. During detection, the detection circuit 200 is connected in series with the electrical component 110, that is, the two have the same current.

[0069] Specifically, the detection circuit 200 includes a detection interface 40 , a current transformer CTM, at least one shunt branch 10 and a current acquisition circuit 20 .

[0070] Among them, the detection interface 40 is used to be connected in series with the DC bus 102 of the electrical component 110. The primary coil of the current transformer CYM (the coil between pins 2 and 3 in the figure) is connected in series with the detection interface 40. The shunt branch 10 is also connected in series with the detection interface and in parallel with the primary coil of the current transformer CTM. Thus, the shunt branch 10 and the primary coil of the current transformer CTM shunt the current in the DC bus 102, that is, the working current of the electrical component 110 is shunt. Each shunt branch 10 includes a switch module 11, and the switch module 11 is constructed to be current-conductive. The current acquisition circuit 20 is connected to the secondary coil of the current transformer CTM (the coil between pins 1 and 4 in the figure) for collecting the current signal in the secondary coil. The negative terminal (e.g., pin 4) of the secondary coil is grounded.

[0071] In the present application, the switch module 11 is configured to conduct current, which means that when the current flowing through the switch module 11 exceeds a certain threshold, the current flowing through the switch module 11 will increase rapidly, which is called the switch module 11 being conducted. The current after conduction is much greater than the current before conduction.

[0072] Thus, the current in the primary coil of the current transformer CTM is related to the working current of the electrical component 110, so that the current in the secondary coil of the current transformer CTM is also related to the working current of the electrical component 110. Therefore, by detecting the current signal collected by the current collection circuit 20, it is possible to analyze whether the working current of the electrical component 110 is normal, that is, to analyze whether the electrical component 110 can work normally.

[0073] Preferably, the switch module 11 is configured as a Zener diode 11, the anode of the Zener diode 11 is connected to the negative electrode of the DC bus 102 (that is, the negative electrode of the DC power supply 101), and the cathode of the Zener diode 11 is connected to the positive electrode of the DC bus 102 (that is, the positive electrode of the DC power supply 101). The switch module 11 can also be configured as other electronic components or composed of multiple electronic components.

[0074] Further, the detection circuit 200 further includes an analysis module 30. The analysis module 30 is connected to the current acquisition circuit 20 to receive the signal acquired by the current acquisition circuit 20. The analysis module 30 is configured as an MCU chip, for example, and analyzes whether the signal is normal through built-in analysis software.

[0075] Specifically, the current acquisition circuit 20 is connected in series with the secondary coil of the current transformer CTM, so that the current in the secondary coil flows through the current acquisition circuit 20. The current acquisition circuit 20, for example, includes a plurality of detection resistors RM connected in series, and the current of the secondary coil flows through the plurality of detection resistors RM in sequence, and a voltage drop is formed on each detection resistor RM. Among them, the common end 21 of two adjacent detection resistors RM is connected to the A / D pin of the analysis module 30, and the analysis module 30 can analyze the current of the secondary coil by detecting the voltage of the common end 21, and further analyze the working current of the electrical component 110. The A / D pin of the analysis module 30 has a very high internal resistance, and will not shunt the current in the current acquisition circuit 20, so as to ensure the accuracy of the detection data.

[0076] In the illustrated embodiment, the current acquisition circuit 20 includes two detection resistors RM1 and RM2, and the voltage value of the common terminal 21 is the product of the current value of the current of the secondary coil and the resistance value of the detection resistor RM1. Of course, the current acquisition circuit 20 may include more detection resistors RM, and the voltage value of the common terminal 21 is the product of the current value of the current of the secondary coil and the sum of the resistance values ​​of all the detection resistors RM between the common terminal 21 and the ground. Usually, there is only one detection resistor RM between the common terminal 21 and the ground.

[0077] Preferably, the current acquisition circuit 20 further includes a filter capacitor CM, which is connected in parallel with a detection resistor (e.g., RM1) among the multiple detection resistors RM connected to the negative electrode of the secondary coil. In other words, the filter capacitor CM is connected between the common terminal 21 and the ground wire. The filter capacitor CM is used to filter high-frequency interference and clutter in the current acquisition circuit 20, for example, it can filter out interference pulses to make the detection more accurate.

[0078] The detection process is to first connect the detection circuit 200 and the electrical component 110 as follows: Figure 1 The electrical components 110 are connected in the manner shown, and then powered on. It can be understood that during the power-on process, the current in the DC bus 102 gradually increases from zero to the normal operating current. The detection circuit 200 analyzes whether the electrical component 110 can work normally by detecting the current of the secondary coil during the power-on process. In other words, the detection circuit 200 analyzes whether the current in the DC bus 102 can gradually increase from zero during the power-on process, thereby determining whether the electrical component 110 can work normally.

[0079] After the electrical component 110 is powered on, the current in the DC bus 102 gradually increases. The shunt branch 10 and the primary coil of the current transformer CTM shunt the current in the DC bus 102. Since direct current flows through the primary coil, the current in the secondary coil changes very little. When the current in the DC bus 102 increases to a certain extent, the current in the shunt branch 10 also increases, causing the Zener diode 11 to be reversely broken down by the current. After the breakdown, the current in the shunt branch 10 will increase significantly, causing the current in the primary coil to decrease significantly. Since the breakdown occurs in a very short period of time, the current in the shunt branch 10 increases suddenly before and after the breakdown, and the current in the primary coil decreases suddenly. Corresponding to the primary coil, when the current suddenly changes, the current in the secondary coil will produce a pulse (mutation) under the action of electromagnetic induction. Thus, the analysis module 30 is configured to determine that the electrical component 110 is normal when a pulse is detected in the current acquisition signal of the secondary coil (indicating that the operating current of the electrical component 110 can gradually increase from zero and the electrical component 110 has power output), and to determine that the electrical component 110 is faulty when no pulse is detected in the signal (indicating that the operating current of the electrical component 110 has not increased).

[0080] It can be understood that the power-on process of the electrical component 110 is completed within a time period, which can be a preset detection time period. The analysis module 30 is configured to determine that the electrical component 110 is normal when a pulse is detected in the current acquisition signal of the secondary coil within the detection time period from the time when the electrical component 110 is powered on, and determine that the electrical component 110 is faulty when no pulse is detected in the signal within the detection time period.

[0081] It can be understood that the parameters of the various components of the detection circuit 200 can be configured according to the normal working current of the electrical component 110, such as the size of the reverse breakdown current of the Zener diode 11, the parameters of the current transformer CTM, etc., so that during the power-on process of the electrical component 110, the Zener diode 11 will definitely be reversely broken down.

[0082] The present application adopts the breakdown and current diversion of the voltage stabilizing diode 11, so that the detection circuit 200 is simple in design and low in cost.

[0083] Preferably, the shunt branch 10 further includes a current limiting resistor 12, which is connected in series with the voltage regulator diode 11 to protect the voltage regulator diode 11. The minimum resistance of the current limiting resistor 12 needs to ensure that the current of the shunt branch 10 does not flow through a current exceeding the limiting current of the voltage regulator diode 11, that is, the voltage regulator diode 11 can be recovered after reverse breakdown (such as Zener breakdown).

[0084] Preferably, the detection circuit 200 has a plurality of shunt branches 10, and the reverse breakdown currents of the Zener diodes 11 in different shunt branches 10 are different. Thus, in the process of powering on the electrical component 110, the Zener diodes 11 of the plurality of shunt branches 10 are reversely broken down in sequence, with the one with a small reverse breakdown current being broken down first, and the one with a large reverse breakdown current being broken down later. This enables the detection circuit 200 to be used to detect DC electrical components 110 with different working currents. Preferably, the resistance values ​​of the current limiting resistors 12 in different shunt branches 10 are different, and the resistance value of the current limiting resistor 12 connected in series with the Zener diode 11 with a larger reverse breakdown current is smaller, and the resistance value of the current limiting resistor 12 connected in series with the Zener diode 11 with a smaller reverse breakdown current is larger.

[0085] In other words, the switch modules 11 in different shunt branches 10 have different conduction currents. When the power-consuming component 110 is powered on, the switch modules 11 of multiple shunt branches 10 are turned on in sequence, with the switch modules 11 of smaller conduction currents turned on first and the switch modules of larger conduction currents turned on later.

[0086] like Figure 1 As shown, the detection circuit 200 includes n shunt branches 10. The first shunt branch 10 has a voltage-stabilizing diode D1 and a current-limiting resistor R1 connected in series, the second shunt branch 10 has a voltage-stabilizing diode D2 and a current-limiting resistor R2 connected in series... The nth shunt branch 10 has a voltage-stabilizing diode Dn and a current-limiting resistor Rn connected in series. Arranged from small to large reverse breakdown current, the n voltage-stabilizing diodes 11 are arranged in the order of D1, D2...Dn. Arranged from large to small resistance values, the n current-limiting resistors 12 are arranged in the order of R1, R2...Dn.

[0087] like Figure 2 As shown, when the electrical component 110 is powered on, the power-on process is manifested in the following stages.

[0088] 1. Phase 1:

[0089] The DC power is output normally. As the power increases, the current I1 (see line C1) from pin 3 to pin 2 of the CTM increases. At this time, I1 is basically the current of the DC bus 102 (the current in each shunt branch 10 is very small). Since it is a continuously changing DC power, the current I2 (see line C2) from pin 4 to pin 1 of the CTM basically does not change.

[0090] 2. Phase 2:

[0091] The current of the DC bus 102 continues to increase. When the current in the DC bus 102 increases to a certain level, so that the current in the first shunt branch 10 reaches the reverse breakdown current of the Zener diode D1, the Zener diode D1 is reversely broken down (the Zener diode with a small breakdown current is broken down first), so that the current of the branch 10 where the Zener diode D1 is located suddenly increases, and a part of the bus current is divided, so that the current I1 in the primary coil suddenly decreases. At this time, due to the sudden decrease in the value of I1, according to the electromagnetic induction phenomenon, the secondary coil will generate an induced current, forming a pulsed current I2, which is input into the MCU chip after post-stage sampling and filtering, and the MCU chip detects the pulse.

[0092] 3. Phase 3:

[0093] As the power continues to increase, the current in the DC bus 102 continues to increase, and the increased current basically flows through the primary coil, and the current I1 from pin 3 to pin 2 of the CTM continues to increase on the basis of stage 2. Since it is a continuously changing DC power, the current I2 from pin 4 to pin 1 of the CTM does not change.

[0094] 4. Phase 4:

[0095] The current in the DC bus 102 continues to increase. When the current in the second shunt branch 10 reaches the reverse breakdown current of the Zener diode D2, the Zener diode D2 is reversely broken down and divides a part of the bus current, causing the value of I1 to suddenly decrease again. According to the electromagnetic induction phenomenon, an induced current will be generated in the secondary coil again, that is, I2 will show a pulse change again. After post-stage sampling and filtering, the pulse is detected by the MCU chip.

[0096] Thus, as the current in the DC bus 102 continues to increase, each Zener diode 11 is reversely broken down in turn, and the current in the secondary coil presents pulses in turn, so that the MCU chip determines whether the electrical component 110 can work normally according to whether the pulse can be detected. The MCU chip can be connected to a display device to display the detection result. Of course, the detection circuit 200 can also detect the current pulse in the secondary coil in the form of a hardware circuit. For example, the analysis module 30 constructs a hardware trigger circuit that matches the current pulse, and determines whether the electrical component 110 can work normally according to whether a trigger result is generated.

[0097] In stage 3, the voltage-stabilizing diode D1 has been reversely broken down, and current flows through its shunt branch 10. At this time, the voltage-stabilizing diode D1 is similar to a resistor, which is connected in series with the current-limiting resistor R1, and a voltage drop is formed at both ends of the voltage-dividing branch 10. It can be understood that the voltage drop is not enough to cause the voltage-stabilizing diodes 11 in other shunt branches 10 to be reversely broken down. Preferably, the reverse breakdown voltages of the voltage-stabilizing diodes 11 in different shunt branches 10 are different, and the reverse breakdown voltage of the voltage-stabilizing diodes 11 with a larger reverse breakdown current is larger, and the reverse breakdown voltage of the voltage-stabilizing diodes 11 with a smaller reverse breakdown current is smaller. Thus, the voltage at both ends of the shunt branch 10 that is broken down first will not cause other shunt branches to be broken down at the same time, so that each shunt branch 10 is broken down in turn, and current pulses can be detected in the secondary coil in turn, indicating that the current in the DC bus 102 is gradually increasing. This makes the detection circuit 200 suitable for detecting electrical components 110 with different working currents.

[0098] It can be understood that when the power-consuming component 110 is powered off, the current in the DC bus 102 gradually decreases to zero, and the multiple voltage-stabilizing diodes 11 are restored in sequence, with the first to be broken down being restored first. Similarly, during the recovery phase of the voltage-stabilizing diode 11, the current in the primary coil of the CTM will suddenly decrease, which causes a reverse pulse to be generated in the secondary coil.

[0099] The number of shunt branches 10 can be designed according to the maximum power, maximum current, etc. of the electrical component 110, and the voltage-regulating diode 11 and the current-limiting resistor 12 in each shunt branch 10 can be matched, so that each shunt branch 10 is reversely broken down in turn, and the broken-down shunt branch 10 will not form a breakdown voltage on the unbroken shunt branch 10.

[0100] By selecting a CTM with a suitable input-output ratio, the current output by the secondary coil can be reduced, so that the detection resistor RM generates less heat. In addition, the detection circuit 200 is not directly connected to an AC power source, so it is more convenient to install.

[0101] The detection circuit 200 can be used to detect a variety of DC power components 110. Preferably, the detection circuit 200 is used to detect the DC power components 110 in the cooking appliance. For the convenience of detection, the detection circuit 200 can be integrated in the cooking appliance, so that the detection can be performed anytime and anywhere. Figure 3 and Figure 4 As shown, in a specific embodiment, the cooking appliance 100 may include an electrical component 110 driven by direct current and a detection circuit 200 , wherein the detection interface 40 of the detection circuit 200 is used to be connected in series with the DC bus 102 of the electrical component 110 .

[0102] In order to enable the electrical component 110 to work normally and cooperate with the inspection, the cooking appliance 100 further includes a selective connection element 120. The selective connection element 120 has a first connection state and a second connection state. The selective connection element 120 is configured to electrically decouple the detection circuit 200 from the electrical component 110 in the first connection state, and to connect the electrical component 110 and the detection circuit 200 in series in the second connection state. That is, the state of the selective connection element 120 determines whether the electrical component 110 works normally or is under inspection.

[0103] like Figure 3 As shown, the connection element 120 is selected as a short-circuit terminal. The short-circuit terminal is connected in series in the DC bus 102. The two ends of the short-circuit terminal are respectively connected to the two ends of the detection interface 40, so that the short-circuit terminal is connected in parallel with the detection circuit 200. When the short-circuit terminal is short-circuited, the connection element 120 is selected to be in a first connection state, the short-circuit terminal short-circuits the detection circuit 200, the current in the DC bus 102 does not flow through the detection circuit 200, and the electrical component 110 works normally. When the short-circuit terminal is disconnected, the connection element 120 is selected to be in a second connection state, the electrical component 110 and the detection circuit 200 are connected in series, so that the detection circuit 200 can detect whether the electrical component 110 can work normally.

[0104] like Figure 4 As shown, the selective connection element 120 is a single-pole double-throw switch. The first free end 122 and the fixed end 121 of the single-pole double-throw switch are connected in series in the DC bus 102. The two free ends 122 and 123 of the single-pole double-throw switch are respectively connected to the two ends of the detection interface 40. When the fixed end 121 is connected to the first free end 122, the selective connection element 120 is in the first connection state, the detection circuit 200 is in the open circuit state, the current in the DC bus 102 does not flow through the detection circuit 200, and the electrical component 110 works normally. When the fixed end 121 is connected to the second free end 123, the selective connection element 120 is in the second connection state, the electrical component 110 and the detection circuit 200 are connected in series, so that the detection circuit 200 can detect whether the electrical component 110 can work normally.

[0105] Other designs of the optional connecting element 120 are also possible.

[0106] The electrical component 110 may be a motor, a relay, an electromagnetic oscillation coil, etc.

[0107] Of course, the detection circuit 200 may not be integrated into the cooking appliance, but may be packaged in a special detection device. The detection device may have multiple detection functions, for example, and the detection circuit 200 provides one of the functions.

[0108] The processes and steps described in all the above preferred embodiments are only examples. Unless adverse effects occur, various processing operations can be performed in a sequence different from the sequence of the above processes. The sequence of steps in the above processes can also be increased, merged or deleted according to actual needs.

[0109] In understanding the scope of the present application, the term "comprising" and its derivatives as used herein are intended to be open terms, which specify the existence of the recorded features, elements, components, groups, wholes and / or steps, but do not exclude the existence of other unrecorded features, elements, components, groups, wholes and / or steps. This concept also applies to words with similar meanings, such as the terms "including", "having" and their derivatives.

[0110] The terms "attached" or "attached" as used herein include: a configuration where an element is directly secured to another element by directly securing the element to the other element; a configuration where an element is indirectly secured to another element by securing the element to an intermediate member which in turn is secured to the other element; and a configuration where one element is integral with the other element, i.e., one element is substantially a part of the other element. This definition also applies to words with similar meanings such as "connect," "connect," "couple," "mount," "bond," "fix," and their derivatives. Finally, terms of degree such as "substantially," "approximately," and "approximately" as used herein represent the amount of deviation that modifies the term such that the end result will not be significantly changed.

[0111] Unless otherwise defined, the technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present application. The terms used herein are only for describing specific implementation purposes and are not intended to limit the present application. The features described herein in one embodiment may be applied to another embodiment individually or in combination with other features, unless the feature is not applicable or otherwise specified in the other embodiment.

[0112] The present application has been described through the above-mentioned embodiments, but it should be understood that the above-mentioned embodiments are only for the purpose of example and description, and are not intended to limit the present application to the described embodiments. In addition, it can be understood by those skilled in the art that the present application is not limited to the above-mentioned embodiments, and more variations and modifications can be made according to the teachings of the present application, and these variations and modifications all fall within the scope of protection claimed by the present application.

Claims

1. A detection circuit for detecting a DC-driven electrical component, characterized in that: The detection circuit comprises: A detection interface, used to be connected in series with a DC bus of the DC-driven electrical component; A current transformer, wherein the primary coil of the current transformer is connected in series with the detection interface; at least one shunt branch, the shunt branch being connected in series with the detection interface and in parallel with the primary coil of the current transformer, the shunt branch comprising a switch module, the switch module being configured to conduct current; and A current acquisition circuit is connected to the secondary coil of the current transformer and is used to acquire a current signal in the secondary coil.

2. The detection circuit according to claim 1, characterized in that: The switch module is configured as a voltage-stabilizing diode, an anode of the voltage-stabilizing diode is connected to a negative electrode of the DC bus, and a cathode of the voltage-stabilizing diode is connected to a positive electrode of the DC bus.

3. The detection circuit according to claim 2, characterized in that: The shunt branch further includes a current limiting resistor, which is connected in series with the voltage stabilizing diode.

4. The detection circuit according to claim 3, characterized in that: The detection circuit includes a plurality of shunt branches, and the reverse breakdown currents of the voltage regulator diodes in different shunt branches are different.

5. The detection circuit according to claim 4, characterized in that: The reverse breakdown voltages of the Zener diodes in different shunt branches are different. The reverse breakdown voltage of the Zener diode with a larger reverse breakdown current is larger, and the reverse breakdown voltage of the Zener diode with a smaller reverse breakdown current is smaller.

6. The detection circuit according to claim 4, characterized in that: The resistance values ​​of the current limiting resistors in different shunt branches are different. The resistance value of the current limiting resistor connected in series with the voltage zener diode with a larger reverse breakdown current is smaller, and the resistance value of the current limiting resistor connected in series with the voltage zener diode with a smaller reverse breakdown current is larger.

7. The detection circuit according to claim 1, characterized in that: There are a plurality of shunt branches, and the conduction currents of the switch modules in different shunt branches are different.

8. The detection circuit according to any one of claims 1 to 7, characterized in that: The current collection circuit is connected in series with the secondary coil of the current transformer, and the current collection circuit includes a plurality of detection resistors connected in series.

9. The detection circuit according to claim 8, characterized in that: The current collection circuit further includes a filter capacitor, which is connected in parallel with the detection resistor among the multiple detection resistors that is connected to the negative electrode of the secondary coil.

10. A cooking utensil, characterized in that: include: Electrical components driven by direct current; The detection circuit according to any one of claims 1 to 9, wherein the detection interface is used to be connected in series with a DC bus of the electrical component; and A selective connection element is provided, wherein the selective connection element has a first connection state and a second connection state, and is used to electrically decouple the electrical component from the detection circuit in the first connection state, and to connect the electrical component and the detection circuit in series in the second connection state.

11. The cooking device according to claim 10, characterized in that: The selection connection element is configured as a short-circuit terminal or a single-pole double-throw switch; and / or, The electrical component is configured as a motor, or a relay, or an electromagnetic oscillation coil.

12. A detection device for detecting a DC-driven electrical component, characterized in that: The detection device comprises a detection circuit according to any one of claims 1 to 9.

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