Continuous low-power device for induction cooker
By designing a device including EMC, rectifying filtering, resonance, IGBT driving and relay driving circuit in the induction cooker, the problem of uneven heating when the induction cooker is low-power output is solved, low-power continuous heating is achieved, and the loss and temperature rise of the IGBT are reduced.
Patent Information
- Application Number
- CN202422076693.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-27
- Publication Date
- 2025-06-17
- Estimated Expiration
- 2034-08-27
AI Technical Summary
The existing induction cooker is too slow to switch during low power output, resulting in uneven heating, which cannot achieve true low power continuous heating, and the IGBT loss is large and the lifespan is shortened.
By designing devices including EMC circuits, rectifying filter circuits, resonant circuits, IGBT driving circuits and relay driving circuits in the induction cooker, the "hard switching" condition of the IGBT is reduced and the low-power continuous heating is achieved.
The low-power continuous heating of the induction cooker is realized, which reduces the loss and temperature rise of the IGBT and extends the life of the IGBT.
Smart Images
Figure CN222996700U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of electromagnetic cookers, and particularly relates to a continuous low-power device for an electromagnetic cooker. Background Art
[0002] The prior art uses an intermittent heating method to achieve such a low-power output. Although the average power output can reach the predetermined low-power target, this method has a problem that the heating cycle of the electromagnetic cooker switches too slowly (in seconds), and the firepower suddenly turns on and off, resulting in uneven heating. This discontinuous heating method cannot truly achieve a low-power working state, and it takes longer time and consumes more electricity to cook food than the continuous boiling state.
[0003] The prior art electromagnetic cooker cannot truly achieve continuous low-power heating mainly because the magnitude of the heating power is directly proportional to the conduction time of the IGBT. The longer the conduction time, the greater the reverse voltage generated after LC resonance, and the greater the heating power. When the electromagnetic cooker needs to output low power, the conduction time of the IGBT will be reduced, and the pulse width of the driving signal will be shortened. However, when the pulse width is reduced to a certain extent (that is, when the power is reduced to about 1000 W), the reverse voltage generated by LC resonance will have a small swing amplitude of the resonance voltage due to the small energy provided, so that the voltage cannot drop to zero potential when swinging downward, resulting in the next IGBT turning on before the collector-emitter voltage (VCE) drops to zero voltage, forming a so-called "hard switching" state, causing large losses and high temperature rise of the IGBT, and shortening the service life of the IGBT. Summary of the Utility Model
[0004] To solve the problems mentioned in the above background art, the purpose of the utility model is to provide a continuous low-power device for an electromagnetic cooker.
[0005] A continuous low-power device for an electromagnetic cooker of the utility model includes an EMC circuit, a rectifying and filtering circuit, a resonant circuit, an IGBT driving circuit, and a relay driving circuit; the EMC circuit is electrically connected to the rectifying and filtering circuit, the rectifying and filtering circuit is respectively connected to the resonant circuit and the IGBT driving circuit, the resonant circuit and the IGBT driving circuit are connected to the relay driving circuit, the resonant circuit is used for the continuous low-power mode, and the relay driving circuit is used for the switching of the resonant circuit.
[0006] Preferably, the EMC circuit includes a varistor and a line filter capacitor; one end of the live wire of the mains is connected to one end of the fuse, and the other end of the fuse and the neutral wire of the mains are respectively connected to both ends of the varistor and the line filter capacitor.
[0007] Preferably, the rectifying and filtering circuit includes a rectifier bridge, an inductor, and a smoothing filter capacitor; one end of the 1 terminal of the rectifier bridge is connected to one end of the inductor, the other end of the inductor is connected to one end of the smoothing filter capacitor, the other end of the smoothing filter capacitor is connected to one end of the third resistor, and the other end of the third resistor is connected to the V- terminal of the rectifier bridge and grounded.
[0008] Preferably, the resonant circuit includes a first resonant capacitor, a second resonant capacitor, and a coil disk; one ends of the first resonant capacitor, the second resonant capacitor, and the coil disk are connected together, the other ends of the first resonant capacitor and the coil disk COIL1 are connected together and connected to the relay drive circuit, and the other end of the second resonant capacitor is connected to the relay drive circuit.
[0009] Preferably, the relay drive circuit includes a diode, a relay, a triode, and a second resistor; the positive and negative electrodes of the diode are respectively connected to the 3 and 4 terminals of the relay coil, the 4 terminal of the relay coil is connected to the C electrode of the triode, the E electrode of the triode is grounded, and the B electrode of the triode is connected to the second resistor.
[0010] Preferably, the IGBT drive circuit includes an IGBT module, a first resistor, and a main control chip; the 6th pin of the main control chip is connected to one end of the first resistor, and the other end of the first resistor is connected to the G electrode of the IGBT module.
[0011] A method for realizing continuous low power of a continuous low-power device for an induction cooker: When an output of less than 1000W of low power is required, the second resonant capacitor is disconnected from the resonant circuit through the relay drive circuit, and the first resonant capacitor and the coil disk are changed to form a resonant circuit. When continuously heating at a power lower than 1000W, the reverse voltage generated by LC resonance can swing lower due to the reduction of the resonant capacitor in the resonant circuit, thereby reducing or weakening the "hard switching" condition of the IGBT, and naturally reducing the loss and temperature rise of the IGBT.
[0012] Compared with the prior art, the beneficial effects of the present utility model are: Low-power continuous heating is realized through the mutual cooperation of the EMC circuit, the rectifying and filtering circuit, the resonant circuit, the IGBT drive circuit, and the relay drive circuit. The specific advantages are:
[0013] 1. By switching the resonant capacitor, continuous low-power heating of the induction cooker can be realized.
[0014] 2. Reduce or weaken the "hard switching" condition of the IGBT, and naturally reduce the loss and temperature rise of the IGBT. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] For ease of explanation, the present utility model will be described in detail by the following specific embodiments and accompanying drawings.
[0016] Figure 1 It is the circuit diagram of the present utility model;
[0017] Figure 2 is the flow chart of the present utility model;
[0018] Figure 3 is another circuit diagram of the present utility model.
[0019] In the figure: FU1 - fuse; RT1 - varistor; C1 - bypass filter capacitor; DB1 - rectifier bridge; L1 - inductor; C2 - smoothing filter capacitor; C3 - resonance capacitor 1; C4 - resonance capacitor 2; COIL1 - coil; D1 - diode; REL1 - relay; Q1 - triode; IGBT1 - IGBT module; R905 - resistor 1; R906 - resistor 2; R3 - resistor 3; U1 - main control chip; Detailed implementation manners
[0020] To make the objectives, technical solutions and advantages of the present utility model clearer and more understandable, the present utility model will be described below through specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present utility model. The structures, ratios, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those skilled in the art to understand and read, and are not used to limit the implementation conditions of the present utility model. Therefore, they do not have any technical substance. Any modification of the structure, change of the ratio relationship or adjustment of the size, without affecting the effects that the present utility model can produce and the objectives that can be achieved, should still fall within the scope covered by the technical content disclosed in the present utility model. In addition, in the following description, the descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present utility model.
[0021] Here, it should also be noted that in order to avoid obscuring the present utility model due to unnecessary details, only the structures and / or processing steps closely related to the solution according to the present utility model are shown in the drawings, while other details less related to the present utility model are omitted.
[0022] Detailed implementation manner 1: As Figure 1 、 Figure 2As shown in the figure, the present specific embodiment adopts the following technical solutions: It includes an EMC circuit, a rectifier filter circuit, a resonant circuit, an IGBT drive circuit, and a relay drive circuit; the EMC circuit is electrically connected to the rectifier filter circuit, the rectifier filter circuit is respectively connected to the resonant circuit and the IGBT drive circuit, the resonant circuit and the IGBT drive circuit are connected to the relay drive circuit, the resonant circuit is used for continuous low-power mode, and the relay drive circuit is used for the switching of the resonant circuit; the EMC circuit includes a varistor RT1 and a line filter capacitor C1; the rectifier filter circuit includes a rectifier bridge DB1, an inductor L1, and a smoothing filter capacitor C2; the resonant circuit includes a first resonant capacitor C3, a second resonant capacitor C4, and a coil COIL1, and the relay drive circuit includes a diode D1, a relay REL1, a triode Q1, and a resistor R906; the IGBT drive circuit includes an IGBT module IGBT1, a resistor R905, and a main control chip U1; the live wire of the mains is connected to one end of a fuse FU1, and the other end of the fuse FU1 and the neutral wire of the mains are respectively connected to both ends of the varistor RT1, the line filter capacitor C1, the 2 terminal of the rectifier bridge DB1, and the AC terminal. The 1 terminal of the rectifier bridge DB1 is connected to one end of the inductor L1, and the other end of the inductor L1 is respectively connected to one end of the smoothing filter capacitor C2, one end of the first resonant capacitor C3, one end of the second resonant capacitor C4, and one end of the coil COIL1. The other end of the smoothing filter capacitor C2 is respectively connected to one end of a resistor R3 and the E pole of the IGBT module IGBT1. The other end of the resistor R3 is connected to the V- terminal of the rectifier bridge DB1 and grounded. The other end of the coil COIL1 is respectively connected to the C pole of the IGBT module IGBT1, the other end of the first resonant capacitor C3, and the 1 pin of the normally open contact of the relay REL1. The other end of the second resonant capacitor C4 is connected to the 2 pin of the normally open contact of the relay REL1. The positive and negative poles of the diode D1 are respectively connected to the 3 and 4 terminals of the coil of the relay REL1. The 4 terminal of the coil of the relay REL1 is connected to the C pole of the triode Q1. The E pole of the triode Q1 is grounded. The B pole of the triode Q1 is connected to one end of the resistor R906. The other end of the resistor R906 is connected to the 5 pin of the main control chip U1. The 6 pin of the main control chip U1 is connected to one end of the resistor R905. The other end of the resistor R905 is connected to the G pole of the IGBT module IGBT1.
[0023] As Figure 2As shown in the figure, a method for a continuous low-power device for an induction cooker to achieve continuous low power: when an output below 1000W of low power is required, the resonance capacitor C4 is disconnected from the resonance circuit through a relay drive circuit, and instead, a resonance circuit is formed by the resonance capacitor C3 and the coil COIL1. When continuously heating at a power below 1000W, the reverse voltage generated by LC resonance can swing lower due to the reduction of the resonance capacitor in the resonance circuit, thereby reducing or weakening the "hard switching" condition of the IGBT, and reducing the loss and temperature rise of the IGBT.
[0024] Specific implementation method 2: As Figure 3 shown in the figure, the difference between this specific implementation method and the first specific implementation method is that the resonance capacitor C4 is the second coil COIL2. Using the second coil COIL2 to replace the resonance capacitor C4 and adopting the method of switching the heating coil can also achieve continuous low-power heating.
[0025] This specific implementation method realizes continuous low-power heating by switching the resonance capacitor or the coil to reduce the effective reactance in the resonance circuit.
[0026] For those skilled in the art, it is obvious that the present utility model is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of the present utility model, the present utility model can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present utility model is defined by the appended claims rather than the above description. Therefore, it is intended to include all changes falling within the meaning and scope of the equivalent elements of the claims in the present utility model.
[0027] In addition, it should be understood that although this specification is described according to the implementation methods, not every implementation method only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.
Claims
1. A continuous low-power device for an induction cooker, characterized in that: It includes an EMC circuit, a rectifier and filter circuit, a resonant circuit, an IGBT drive circuit, and a relay drive circuit; the EMC circuit is electrically connected to the rectifier and filter circuit, the rectifier and filter circuit are respectively connected to the resonant circuit and the IGBT drive circuit, the resonant circuit, the IGBT drive circuit are connected to the relay drive circuit, the resonant circuit is used for continuous low-power mode, and the relay drive circuit is used for switching the resonant circuit.
2. A continuous low-power device for an induction cooker according to claim 1, characterized in that: The EMC circuit comprises a varistor (RT1) and a cross-line filter capacitor (C1); the live wire of the mains is connected to one end of the fuse (FU1), and the other end of the fuse (FU1) and the neutral wire of the mains are respectively connected to the varistor (RT1) and the two ends of the cross-line filter capacitor (C1).
3. The continuous low-power device for an induction cooker according to claim 1, characterized in that: The rectifier and filter circuit comprises a rectifier bridge (DB1), an inductor (L1), and a smoothing filter capacitor (C2); one end of the rectifier bridge (DB1) is connected to one end of the inductor (L1), the other end of the inductor (L1) is connected to one end of the smoothing filter capacitor (C2), the other end of the smoothing filter capacitor (C2) is connected to one end of a resistor three (R3), and the other end of the resistor three (R3) is connected to a V-end of the rectifier bridge (DB1) and is grounded.
4. The continuous low-power device for an induction cooker according to claim 1, characterized in that: The resonant circuit includes a resonant capacitor 1 (C3), a resonant capacitor 2 (C4), and a wire drum (COIL1); one end of the resonant capacitor 1 (C3), the resonant capacitor 2 (C4), and the wire drum (COIL1) are connected; the other ends of the resonant capacitor 1 (C3) and the wire drum (COIL1) are connected and connected to a relay drive circuit; the other end of the resonant capacitor 2 (C4) is connected to the relay drive circuit.
5. The continuous low-power device for an induction cooker according to claim 1, characterized in that: The relay drive circuit comprises a diode (D1), a relay (REL1), a transistor (Q1), and a resistor (R906); the positive and negative electrodes of the diode (D1) are respectively connected to the 3rd and 4th ends of the relay (REL1) coil, the 4th end of the relay (REL1) coil is connected to the C pole of the transistor (Q1), the E pole of the transistor (Q1) is grounded, and the B pole of the transistor (Q1) is connected to the resistor (R906).
6. The continuous low-power device for an induction cooker according to claim 1, characterized in that: The IGBT drive circuit comprises an IGBT module (IGBT1), a resistor 1 (R905), and a main control chip (U1); pin 6 of the main control chip (U1) is connected to one end of the resistor 1 (R905), and the other end of the resistor 1 (R905) is connected to the G pole of the IGBT module (IGBT1).