CN204634074U - Electromagnetic heating system and its switching tube opening control device - Google Patents

Abstract

What the utility model discloses a kind of electromagnetic heating system and switching tube thereof opens control device, electromagnetic heating system comprises the drive circuit of resonant circuit and the driving switch pipe be made up of heater coil, resonant capacitance and switching tube, open control device to comprise: current transformer, the armature winding of current transformer is connected between the emitter of switching tube and ground, and current transformer generates current detection signal according to the electric current flowing through switching tube; Voltage detecting circuit, voltage detecting circuit is according to current detection signal formation voltage detection signal; Main control unit, main control unit is connected with voltage detecting circuit respectively with drive circuit, main control unit obtains the immediate current flowing through switching tube according to voltage detection signal, and the heating power of electromagnetic heating system is adjusted according to the immediate current flowing through switching tube, meet to make switching tube and default open requirement, thus, can by switching tube adjustment to preset open require lower open-minded, adapt to different pans better, meet consumers' demand.

Description

Electromagnetic heating system and its switching tube opening control device

technical field

The utility model relates to the technical field of living appliances, in particular to an opening control device for a switch tube in an electromagnetic heating system, an electromagnetic heating system and an opening control device for a switch tube in the electromagnetic heating system.

Background technique

The most ideal state when the IGBT tube is turned on is that Uce' (the voltage between the collector and emitter of the IGBT tube) is zero and the reverse freewheeling current is also zero, but due to the limitations of actual conditions, Uce' is in many cases Neither can oscillate to zero. The smaller the heating power, the harder it is for Uce' to oscillate to zero. At this time, the IGBT is turned on in advance; the reverse freewheeling current is also difficult to be zero in many cases. The larger the heating power, the reverse freewheeling current The larger the current may be, the opening at this time is hysteresis opening.

In the related art, the minimum value and the maximum value of the heating power are generally determined through experiments, so that Uce' is smaller than the preset voltage and the reverse freewheeling current is smaller than the preset current. However, its disadvantage is that Uce' and reverse freewheeling current can only be adjusted to the preset range when using known cookware, and for some unknown cookers, it is impossible to guarantee that Uce' and reverse freewheeling current are both In the preset range, this may cause the IGBT tube to overheat and even cause damage. Therefore, there is a need for improvement in the related art.

Utility model content

The utility model aims to solve one of the technical problems in the related art at least to a certain extent. Therefore, an object of the present utility model is to provide an opening control device for the switching tube in the electromagnetic heating system, which can intelligently adjust the switching tube to open according to the preset opening requirement.

Another purpose of the utility model is to provide an electromagnetic heating system.

In order to achieve the above-mentioned purpose, the utility model proposes an opening control device for a switching tube in an electromagnetic heating system. The driving circuit, the opening control device includes: a current transformer, the primary winding of the current transformer is connected between the emitter of the switching tube and the ground, and the current transformer is based on the current flowing through the switching tube The current generates a current detection signal; a voltage detection circuit, the voltage detection circuit generates a voltage detection signal according to the current detection signal; a main control unit, the main control unit is connected to the drive circuit and the voltage detection circuit respectively, the The main control unit obtains the instantaneous current flowing through the switch tube according to the voltage detection signal, and adjusts the heating power of the electromagnetic heating system according to the instantaneous current flowing through the switch tube, so that the switch tube meets the preset requirements. set activation requirements.

According to the opening control device of the switch tube in the electromagnetic heating system proposed by the utility model, the current flowing through the switch tube is detected by the current transformer, and the current detection signal is converted into a voltage detection signal by the voltage detection circuit. The signal acquires the instantaneous current flowing through the switching tube, and adjusts the heating power of the electromagnetic heating system according to the instantaneous current flowing through the switching tube, so that the switching tube meets the preset opening requirements, so that the switching tube can be intelligently adjusted to the preset opening It can be turned on according to the requirements, better adapt to different pots and pans, meet the needs of users, and can avoid the heat or even damage of the switch tube due to advanced or delayed turn-on.

Further, when the instantaneous current flowing through the switch tube is greater than the first current threshold, the main control unit judges that the switch tube is turned on in advance, and increases the heating power of the electromagnetic heating system, wherein the first The current threshold is greater than zero; when the instantaneous current flowing through the switch tube is less than the second current threshold, the main control unit judges that the switch tube is turned on with a delay, and reduces the heating power of the electromagnetic heating system, wherein the The second current threshold is less than zero.

Specifically, the switch tube may be an IGBT tube, the C pole of the IGBT tube is connected to the heating coil and the resonant capacitor connected in parallel, and the E pole of the IGBT tube is grounded through the primary winding of the current transformer, so The G pole of the IGBT tube is connected with the drive circuit.

In order to achieve the above purpose, another aspect of the utility model proposes an electromagnetic heating system, including the above-mentioned switching tube opening control device.

According to the electromagnetic heating system proposed in the utility model, the switching tube can be intelligently adjusted to the preset opening requirements, so as to better adapt to different pots and utensils and meet the needs of users.

Specifically, the electromagnetic heating system may include an electromagnetic cooker, an electromagnetic rice cooker, and an electromagnetic pressure cooker.

Description of drawings

Fig. 1 is a schematic diagram of an opening control device for a switching tube in an electromagnetic heating system according to an embodiment of the present invention;

Figure 2 is a schematic diagram of voltage and current waveforms when the switch tube is turned on in advance;

Fig. 3 is a schematic diagram of voltage and current waveforms when the switching tube is turned on with hysteresis; and

Fig. 4 is a schematic diagram of an on-off control device for a switch tube in an electromagnetic heating system according to a specific embodiment of the present invention.

Reference signs:

Heating coil L2, resonant capacitor C2, switch tube Q1, resonant circuit 20, drive circuit 30, opening control device 10, current transformer T1, voltage detection circuit 101, main control unit 102, filter inductor L1, filter capacitor C1 and rectifier 40 .

Detailed ways

Embodiments of the present invention are described in detail below, examples of which are shown in the drawings, wherein the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the figures are exemplary and are intended to explain the present invention, but should not be construed as limiting the present invention.

The opening control device of the switch tube in the electromagnetic heating system and the electromagnetic heating system proposed by the embodiments of the present invention will be described below with reference to the accompanying drawings, wherein the electromagnetic heating system is used to heat the pan.

Fig. 1 is a schematic diagram of an on-off control device for a switching tube in an electromagnetic heating system according to an embodiment of the present invention. As shown in FIG. 1 , the electromagnetic heating system includes a resonant circuit 20 composed of a heating coil L2 , a resonant capacitor C2 and a switch tube Q1 , and a drive circuit 30 for driving the switch tube Q1 . Wherein, the resonant circuit 20 is used for resonantly heating the pot, specifically, when the switch tube Q1 is turned on under the drive of the drive circuit 30, the heating coil L2 is charged, in order to maintain the connection between the heating coil L2 and the resonant capacitor C2 To prepare for oscillation, when the switch tube Q1 is turned off under the drive of the drive circuit 30, the heating coil L2 and the resonant capacitor C2 oscillate. As a result, an alternating magnetic field is generated around the heating coil L2, and most of the magnetic field lines of the alternating magnetic field pass through the pot and generate a large amount of eddy currents in the bottom of the pot, thereby generating heat required for cooking.

In the embodiment of the present invention, as shown in FIG. 1 , the opening control device 10 includes: a current transformer T1 , a voltage detection circuit 101 and a main control unit 102 . The primary winding of the current transformer T1 is connected between the emitter of the switch tube Q1 and the ground, the current transformer T1 generates a current detection signal according to the current flowing through the switch tube Q1; the voltage detection circuit 101 generates a voltage detection signal according to the current detection signal, The voltage detection circuit 101 is connected to both ends of the secondary winding of the current transformer T1. That is to say, the current transformer T1 is used to detect the current flowing through the switch tube Q1 and generate a current detection signal, and the voltage detection circuit 101 is used to convert the current detection signal into a corresponding voltage detection signal. It should be noted that, as shown in FIG. 1 , the current flowing through the switch tube Q1 may be the current flowing from the collector to the emitter of the switch tube Q1 , and the reverse freewheeling current flowing through the body diode of the switch tube Q1 .

The main control unit 102 is connected to the driving circuit 30 and the voltage detection circuit 101 respectively. The main control unit 102 is used to obtain the instantaneous current flowing through the switch tube Q1 according to the voltage detection signal, and adjust the electromagnetic heating system according to the instantaneous current flowing through the switch tube. The heating power is used to make the switching tube Q1 meet the preset turn-on requirements. That is to say, the main control unit 102 can output a PWM control signal to the driving circuit 30 to make the driving circuit 30 drive the switch Q1 to turn on or off, and the main control unit 102 can also obtain the voltage detection signal generated by the voltage detection circuit 101 .

According to an example of the present invention, the main control unit 102 pre-stores the relational expression between the voltage and the current. After the main control unit 102 obtains the voltage detection signal, it can calculate the instantaneous current

In addition, it should be noted that the preset turn-on requirement specifically means that the voltage Uce between the collector and the emitter of the switch tube Q1 is less than a preset voltage, and the reverse freewheeling current is less than a preset current.

It should also be noted that factors such as pot and heating power will affect the opening of the switch tube Q1. If the heating power is low, the switching tube Q1 may be turned on ahead of time; if the heating power is high, the switching tube Q1 may be turned on laggingly, the heating power can be adjusted to make the switching tube Q1 meet the preset opening requirements, and then the electromagnetic The heating system adapts to different pans.

During the heating process of the electromagnetic heating system, the current flowing through the switch tube Q1 can be detected by the current transformer T1 when the switch tube Q1 is turned on, so as to determine whether the switch tube Q1 is turned on in advance or delayed. The voltage detection circuit 101 converts the current detection signal into a corresponding voltage detection signal, and sends the voltage detection signal to the main control unit 102. When the switch tube Q1 is turned on, the main control unit 102 can receive the voltage detection signal, and according to the voltage detection signal and The preset voltage-current relationship formula calculates the instantaneous current flowing through the switch tube Q1, and judges whether the switch tube Q1 meets the preset turn-on requirement according to the instantaneous current of the switch tube. If it is satisfied, the current heating power is maintained; if it is not satisfied, that is, the switch tube Q1 is turned on in advance or lags behind, then the heating power is adjusted.

Therefore, the switch tube opening control device in the electromagnetic heating system proposed by the embodiment of the utility model detects the current flowing through the switch tube through the current transformer, and converts the current detection signal into a voltage detection signal through the voltage detection circuit. The unit obtains the instantaneous current flowing through the switch tube according to the voltage detection signal, and adjusts the heating power of the electromagnetic heating system according to the instantaneous current flowing through the switch tube, so that the switch tube meets the preset opening requirements, so that the switch tube can be intelligently adjusted It can be opened under the preset opening requirements, better adapt to different pots and pans, meet the needs of users, and can prevent the switch tube from heating or even being damaged due to advanced or delayed opening.

According to a specific example of the present invention, the main control unit 102 can adjust the heating power by adjusting the duty cycle of the output PWM control signal.

Further, according to an embodiment of the present invention, when the instantaneous current flowing through the switch tube Q1 is greater than the first current threshold, the main control unit 102 judges that the switch tube Q1 is turned on in advance, and increases the heating power of the electromagnetic heating system, wherein, The first current threshold is greater than zero; when the instantaneous current flowing through the switch tube Q1 is less than the second current threshold, the main control unit 102 judges that the switch tube Q1 is turned on with a delay, and reduces the heating power of the electromagnetic heating system, wherein the second current threshold less than zero.

It should be noted that when the switch tube Q1 is turned on in advance, the voltage Uce between the collector and the emitter of the switch tube Q1 and the waveform of the current Ice flowing through the switch tube Q1 are shown in Figure 2, and the waveforms of the current Ice flowing through the switch tube Q1 The current Ice of the current Ice will generate a relatively large short-circuit current i1 at the moment of opening, so that the short-circuit current i1 can be detected. If the short-circuit current i1 exceeds the first current threshold, it is judged that the switch tube Q1 is turned on in advance; when the switch tube Q1 lags When it is turned on, the voltage Uce between the collector and emitter of the switch tube Q1 and the waveform of the current Ice flowing through the switch tube Q1 are shown in Figure 3. The reverse freewheeling current -i2 is large, so that the reverse current -i2 can be detected, and if the reverse freewheeling current -i2 exceeds the second current threshold, it is judged that the switching tube Q1 is turned on with a delay.

As mentioned above, the main control unit 102 obtains the instantaneous current flowing through the switch tube Q1 through the current transformer T1. When the switch tube Q1 is turned on, that is, when the PWM control signal output by the main control unit 102 changes from a low level to a high level, if the instantaneous current flowing through the switch tube Q1 is greater than the first current threshold I1, the main control unit 102 increases The heating power of the electromagnetic heating system is to reduce the voltage Uce between the collector and the emitter, so that the voltage Uce drops to less than the preset voltage, which meets the preset opening requirements, so as to better adapt to the pot. If the instantaneous current flowing through the switch tube Q1 is less than the second current threshold I2, the main control unit 102 reduces the heating power of the electromagnetic heating system to reduce the reverse freewheeling current, so that the reverse freewheeling current drops to less than the preset The current meets the preset opening requirements, so as to better adapt to the pot.

Therefore, the opening control device of the embodiment of the utility model can intelligently adjust the switch tube to open under the preset opening requirements, better adapt to different pots, meet the needs of users, and can avoid the switch tube being turned on due to advance or lag. And heat or even damage.

According to a specific embodiment of the present invention, as shown in Figure 4, the heating coil L2 can be connected in parallel with the resonant capacitor C2, the switching tube Q1 can be an IGBT tube, and the C pole of the IGBT tube is connected with the parallel heating coil L2 and the resonant capacitor C2 , the E pole of the IGBT tube is grounded through the primary winding of the current transformer T1, that is, one end of the primary winding of the current transformer T1 is connected to the E pole of the IGBT tube, and the other end of the primary winding of the current transformer T1 is grounded; the IGBT tube The G pole of G is connected with the drive circuit 30.

Further, as shown in FIG. 4 , the electromagnetic heating system may further include a filter inductor L1 , a filter capacitor C1 and a rectifier 40 .

Specifically, one end of the filter inductance L1 is connected to one end of the parallel-connected heating coil L2 and the resonant capacitor C2, wherein, the other end of the parallel-connected heating coil L2 and the resonant capacitor C2 is connected to the C pole of the IGBT tube; the filter capacitor C1 One end is connected to one end of the filter inductor L1, and the other end of the filter capacitor C1 is grounded; the first input end of the rectifier 40 is connected to the live line L of the AC power supply AC, and the second input end of the rectifier 40 is connected to the neutral line N of the AC power supply AC. The first output end of the rectifier 40 is connected to the other end of the filter inductor L1, and the second output end of the rectifier 40 is grounded.

In addition, the embodiment of the present utility model also proposes an electromagnetic heating system, which includes the switch-on control device of the above-mentioned embodiment.

According to the electromagnetic heating system proposed by the embodiment of the utility model, the switching tube can be intelligently adjusted to the preset opening requirements, so as to better adapt to different pots and meet the needs of users.

According to a specific embodiment of the present invention, the electromagnetic heating system may include an electromagnetic cooker, an electromagnetic rice cooker, an electromagnetic pressure cooker, and the like.

In describing the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "Back", "Left", "Right", "Vertical", "Horizontal", "Top", "Bottom", "Inner", "Outer", "Clockwise", "Counterclockwise", "Axial" The orientation or positional relationship indicated by , "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the utility model and simplifying the description, rather than indicating or implying the referred device Or elements must have a specific orientation, be constructed and operate in a specific orientation, and thus should not be construed as limiting the invention.

In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be interpreted as indicating or implying relative importance or implicitly specifying the quantity of indicated technical features. Thus, the features defined as "first" and "second" may explicitly or implicitly include at least one of these features. In the description of the present utility model, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

In this utility model, unless otherwise specified and limited, terms such as "installation", "connection", "connection" and "fixation" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection. Connected, or integrated; may be mechanically or electrically connected; may be directly connected or indirectly connected through an intermediary, and may be an internal communication between two elements or an interactive relationship between two elements, unless otherwise stated Clearly defined. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present utility model according to specific situations.

In the present invention, unless otherwise clearly specified and limited, the first feature may be in direct contact with the first feature or the first feature and the second feature through an intermediary indirect contact. Moreover, "above", "above" and "above" the first feature on the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. "Below", "beneath" and "beneath" the first feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is less horizontally than the second feature.

In the description of this specification, descriptions referring to the terms "one embodiment", "some embodiments", "example", "specific examples", or "some examples" mean that specific features described in connection with the embodiment or example , structures, materials or features are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the described specific features, structures, materials or characteristics may be combined in any suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples and features of different embodiments or examples described in this specification without conflicting with each other.

Although the embodiments of the present invention have been shown and described above, it can be understood that the above-mentioned embodiments are exemplary and should not be construed as limitations of the present invention, and those skilled in the art are within the scope of the present invention. Variations, modifications, substitutions and variations can be made to the above-described embodiments.

Claims (5)

1. A switch-on control device for a switching tube in an electromagnetic heating system, characterized in that, the electromagnetic heating system includes a resonant circuit made up of a heating coil, a resonant capacitor and a switching tube and a drive circuit for driving the switching tube, the Activation controls include: A current transformer, the primary winding of the current transformer is connected between the emitter of the switch tube and the ground, and the current transformer generates a current detection signal according to the current flowing through the switch tube; a voltage detection circuit, the voltage detection circuit generates a voltage detection signal according to the current detection signal; A main control unit, the main control unit is connected to the drive circuit and the voltage detection circuit respectively, the main control unit obtains the instantaneous current flowing through the switch tube according to the voltage detection signal, and obtains the instantaneous current flowing through the switching tube according to the The instantaneous current of the switch tube adjusts the heating power of the electromagnetic heating system, so that the switch tube meets the preset opening requirements. 2. the opening control device of switching tube in the electromagnetic heating system as claimed in claim 1, it is characterized in that, When the instantaneous current flowing through the switch tube is greater than the first current threshold, the main control unit judges that the switch tube is turned on in advance, and increases the heating power of the electromagnetic heating system, wherein the first current threshold is greater than zero; and When the instantaneous current flowing through the switch tube is less than the second current threshold, the main control unit judges that the switch tube is turned on with a delay, and reduces the heating power of the electromagnetic heating system, wherein the second current threshold less than zero. 3. The opening control device of the switch tube in the electromagnetic heating system as claimed in claim 1, wherein the switch tube is an IGBT tube, and the C pole of the IGBT tube is connected to the parallel connection of the heating coil and the resonant capacitor , the E pole of the IGBT tube is grounded through the primary winding of the current transformer, and the G pole of the IGBT tube is connected to the driving circuit. 4. An electromagnetic heating system, characterized in that it comprises the switching tube opening control device according to any one of claims 1-3. 5. The electromagnetic heating system according to claim 4, characterized in that, the electromagnetic heating system comprises an electromagnetic cooker, an electromagnetic rice cooker, and an electromagnetic pressure cooker.