Continuous low-power frequency modulation control circuit and induction cooker

Abstract

The utility model discloses a continuous low power frequency modulation control circuit and induction cooker, including power supply modulation module, electromagnetic coil, switch drive module, zero crossing detection module, switch tube temperature detection module and control module, switch drive module only includes one switch tube I GBT1, switch tube I GBT1 is connected with the electromagnetic coil, zero crossing detection module is connected with the electromagnetic coil, switch tube temperature detection module is connected with the control module, and the control module is connected with the switch tube I GBT1. The zero-cross detection module is connected with the power supply modulation module to detect a zero-cross signal, the switch tube temperature detection module is used for detecting a first temperature signal of the switch tube I GBT1, and the control module is connected with the zero-cross detection module, the switch tube temperature detection module and a controlled end of the switch tube I GBT1. The control module at least can control the switching tube I GBT1 to operate in a first switching mode or a second switching mode, the first switching frequency is greater than the second switching frequency, and the design realizes high-switching-frequency continuous low-power operation and improves the heating effect under the condition of ensuring stable operation of the switching tubes.

Description

Technical Field

[0001] The utility model relates to the technical field of electronic circuits, in particular to a continuous low-power frequency modulation control circuit and an induction cooker. Background Art

[0002] There are many circuit structures for driving the electromagnetic coil of an induction cooker, such as the combination of a rectifier bridge and a switch drive component. The switch drive component is usually composed of multiple switch tubes to apply alternating current to the electromagnetic coil, but the structure is relatively complex and the cost is high.

[0003] Some manufacturers use a switch tube to form a switch drive component. A single tube can significantly reduce the cost of driving the electromagnetic coil. However, when the electromagnetic coil needs to operate at low power, the duty cycle of the switch tube is relatively low. If the control module controls the on and off of the switch tube at a higher switching frequency, the switch tube loss is relatively large. Therefore, the current switch tube can only be turned on and off by continuously turning it on for a period of time and then continuously turning it off for a long period of time. However, this method gives users a poor experience. Users can clearly feel that the induction cooker is in the off state for a long time, and it is also not conducive to heating food. Utility Model Content

[0004] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, the utility model proposes a continuous low-power frequency modulation control circuit and an induction cooker, which can achieve continuous low-power operation with a high switching frequency while ensuring the stable operation of the switch tube, thereby improving the heating effect.

[0005] According to a first aspect of the present invention, a continuous low-power frequency modulation control circuit includes: a power modulation module, an input end of the power modulation module is used to connect to a power supply; an electromagnetic coil; a switch driving module, including only one switch tube IGBT1, the switch tube IGBT1 is connected to the electromagnetic coil to form at least part of a driving power supply branch, and the output end of the power modulation module is connected to the driving power supply branch; a zero-crossing detection module, connected to the power modulation module to detect a zero-crossing signal; a switch tube temperature detection module, used to detect a first temperature signal of the switch tube IGBT1; a control module, respectively connected to the zero-crossing detection module, the switch tube temperature detection module and the controlled end of the switch tube IGBT1, the control module can at least control the switch tube IGBT1 to operate in a first switching mode or in a second switching mode, the control module switches between the first switching mode and the second switching mode according to the first temperature signal, and in the first switching mode, the control module modulates a first switching frequency according to the zero-crossing signal and controls the switch tube IGBT1 to operate in a first switching mode or in a second switching mode. GBT1 operates at a first switching frequency. In a second switching mode, the control module controls the switch tube IGBT1 to operate at a second switching frequency, wherein the first switching frequency is greater than the second switching frequency.

[0006] A continuous low-power frequency modulation control circuit according to an embodiment of the utility model has at least the following beneficial effects:

[0007] In the utility model, when the electromagnetic coil is driven to operate at low power, the zero-crossing detection module can perform zero-crossing detection on the input voltage connected to the input end of the power modulation module, the control module can accurately know the zero point of the input voltage, and can relatively accurately formulate a first switching frequency with a higher switching frequency by frequency hopping in certain bands to control the switch tube IGBT1. The first switching frequency is relatively high, so that the switch tube IGBT1 can achieve continuous low-power operation, and the heating effect of the electromagnetic coil on the heating load is improved. The switch tube temperature detection module will also monitor the first temperature signal of the switch tube IGBT1 at all times. The control module can switch from the first switching mode to the second switching mode. In the second switching mode, the second switching frequency is reduced, and a driving mode of continuously opening for a period of time and then continuously closing for a long period of time is adopted to control the on-off operation of the switch tube IGBT1, so that the temperature of the switch tube IGBT1 decreases. Under the condition of ensuring the stable operation of the switch tube, the design realizes continuous low-power operation with a higher switching frequency and improves the heating effect.

[0008] According to some embodiments of the present utility model, the zero-crossing detection module includes a voltage division detection unit, which includes a resistor R31, a resistor R7 and a capacitor C8, one end of the resistor R31 is connected to the input end of the power modulation module, the other end of the resistor R31 is respectively connected to one end of R7, one end of the capacitor C8 and the control module, and the other end of the resistor R7 and the other end of the capacitor C8 are both grounded.

[0009] According to some embodiments of the present invention, the continuous low-power frequency modulation control circuit further includes a voltage detection module, which is connected to the input end of the power modulation module to detect the input voltage, and the control module is connected to the voltage detection module.

[0010] According to some embodiments of the present invention, the zero-crossing detection module can also detect the input voltage of the input end of the power modulation module.

[0011] According to some embodiments of the present invention, the continuous low-power frequency modulation control circuit includes a synchronous detection module, which is respectively connected to both ends of the electromagnetic coil to detect a load signal, and the control module is connected to the synchronous detection module.

[0012] According to some embodiments of the utility model, the synchronous detection module includes a capacitor C14, a resistor R24, a resistor R36, a resistor R18 and a resistor R35, one end of the capacitor C14 is respectively connected to one end of the electromagnetic coil and one end of the resistor R24, the other end of the capacitor C14 is respectively connected to the other end of the electromagnetic coil and one end of the resistor R18, the other end of R24 is respectively connected to one end of the resistor R36 and the control module, the other end of the resistor R18 is respectively connected to one end of the resistor R35 and the control module, and the other end of the resistor R36 and the other end of the resistor R35 are both grounded.

[0013] According to some embodiments of the present utility model, the switching tube temperature detection module includes a thermistor RT1, a resistor R6 and a resistor R8, one end of the resistor R6 is connected to a power supply, the other end of the resistor R6 is respectively connected to one end of the resistor R8, one end of the thermistor RT1 and a control module, and the other end of the resistor R8 and the other end of the thermistor RT1 are grounded.

[0014] According to some embodiments of the present invention, the continuous low-power frequency modulation control circuit further includes a furnace surface temperature detection module, which is used to detect a second temperature signal driven by the electromagnetic coil to generate heat, and the control module is connected to the furnace surface temperature detection module.

[0015] According to some embodiments of the utility model, the furnace surface temperature detection module includes a resistor R16, a resistor R17, a temperature sensor and a capacitor C4, one end of the resistor R17 is connected to the power supply, the other end of the resistor R17 is respectively connected to one end of the resistor R16, one end of the capacitor C4, the temperature sensor and the control module, and the other end of the resistor R16 and the other end of the capacitor C4 are both grounded.

[0016] The induction cooker according to the embodiment of the second aspect of the utility model comprises the continuous low-power frequency modulation control circuit disclosed in any one of the above embodiments.

[0017] The induction cooker according to the embodiment of the utility model has at least the following beneficial effects:

[0018] The induction cooker of the utility model applies the continuous low-power frequency modulation control circuit disclosed in any of the above embodiments to achieve continuous low-power operation with a higher switching frequency while ensuring stable operation of the switch tube, thereby improving the heating effect.

[0019] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0021] Figure 1 This is a principle structure block diagram of one embodiment of the continuous low-power frequency modulation control circuit of the utility model;

[0022] Figure 2 This is a circuit diagram of a control module of one embodiment of the continuous low-power frequency modulation control circuit of the utility model;

[0023] Figure 3 This is a circuit diagram of a power modulation module and a switch driving module of a control module of one embodiment of the continuous low-power frequency modulation control circuit of the utility model;

[0024] Figure 4 This is a circuit diagram of a voltage regulating module and a zero-crossing detection module in one embodiment of the continuous low-power frequency modulation control circuit of the utility model;

[0025] Figure 5 This is a circuit diagram of a furnace surface temperature detection module in one embodiment of the continuous low-power frequency modulation control circuit of the utility model;

[0026] Figure 6This is a circuit diagram of a switch tube temperature detection module in one embodiment of the continuous low-power frequency modulation control circuit of the utility model.

[0027] Reference numerals:

[0028] The power modulation module 100 , the electromagnetic coil 200 , the switch driving module 300 , the zero-crossing detection module 400 , the switch tube temperature detection module 500 , the control module 600 , the voltage regulation module 700 , the synchronization detection module 800 , and the furnace surface temperature detection module 900 . DETAILED DESCRIPTION

[0029] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0030] In the description of the present invention, it should be understood that descriptions involving orientation, such as the orientations or positional relationships indicated by terms such as "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside", etc., are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0031] In the description of the present utility model, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed" etc. are understood to exclude the number itself, and "above", "below", "within" etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0032] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] like Figure 1-6As shown, according to a first aspect of the present utility model, a continuous low-power frequency modulation control circuit includes a power modulation module 100, an electromagnetic coil 200, a switch driving module 300, a zero-crossing detection module 400, a switch tube temperature detection module 500 and a control module 600, wherein the input end of the power modulation module 100 is used to be connected to a power supply, the switch driving module 300 includes only one switch tube IGBT1, the switch tube IGBT1 is connected to the electromagnetic coil 200 to form at least part of a driving power supply branch, the output end of the power modulation module 100 is connected to the driving power supply branch, the zero-crossing detection module 400 is connected to the power modulation module 100 to detect a zero-crossing signal, the switch tube temperature detection module 500 is used to detect a first temperature signal of the switch tube IGBT1, the control module 600 is respectively connected to the zero-crossing detection module 400, the switch tube temperature detection module 500 and the controlled end of the switch tube IGBT1, and the control module 600 is capable of at least controlling the switch tube IGBT1. GBT1 operates in the first switching mode or in the second switching mode, and the control module 600 switches between the first switching mode and the second switching mode according to the first temperature signal. In the first switching mode, the control module 600 modulates the first switching frequency according to the zero-crossing signal and controls the switch tube I GBT1 to operate at the first switching frequency. In the second switching mode, the control module 600 controls the switch tube I GBT1 to operate at the second switching frequency, wherein the first switching frequency is greater than the second switching frequency.

[0034] Among them, Figure 3 As shown, the power modulation module 100 includes a rectifier unit and an inductive energy storage voltage regulation unit. The rectifier unit may be a full-bridge rectifier structure or a half-bridge rectifier structure composed of multiple diodes, or a rectifier chip may be selected.

[0035] like Figure 2 As shown, the control module 600 can be selected from a processor such as an MCU or a CPU and its associated circuits. It should be noted that the electromagnetic coil 200 can be coupled with a load such as a pot body to heat the pot body. The switch driving module 300 only includes a switch tube I GBT1, the drain of the switch tube I GBT1 is connected to the electromagnetic coil 200, the source of the switch tube I GBT1 is grounded, and the other end of the electromagnetic coil 200 is connected to the output end of the power modulation module 100.

[0036] In some embodiments of the present invention, Figure 4 As shown, it also includes a voltage regulating module 700, the input end of the voltage regulating module 700 is connected to the power supply, and the voltage regulating module 700 can step down the input voltage to modulate it into voltage levels such as 18V, 12V, 5V, 3.3V, etc., to power the control module 600, the switch tube I GBT1 and other components.

[0037] In the continuous low-power frequency modulation control circuit of the utility model, when the electromagnetic coil 200 is driven to operate at low power, the zero-crossing detection module 400 can perform zero-crossing detection on the input voltage connected to the input end of the power modulation module 100, and the control module 600 can accurately know the zero point of the input voltage, and can relatively accurately formulate a first switching frequency with a higher switching frequency by dropping waves and jumping frequencies in certain bands to control the switch tube IGBT1. The first switching frequency is relatively high, so that the switch tube IGBT1 can achieve continuous low-power operation, and the heating effect of the electromagnetic coil 200 on the heating load is improved, and the switch tube temperature detection module 500 will also monitor the first temperature signal of the switch tube IGBT1 at all times. The control module 600 can switch from the first switching mode to the second switching mode. In the second switching mode, the second switching frequency is reduced, and a driving mode of continuously opening for a period of time and then continuously closing for a long period of time is adopted to control the on-off operation of the switch tube IGBT1, so that the temperature of the switch tube IGBT1 decreases. Under the condition of ensuring the stable operation of the switch tube, the design realizes continuous low-power operation with a higher switching frequency and improves the heating effect.

[0038] In some embodiments of the present invention, Figure 4 As shown, the zero-crossing detection module 400 includes a voltage division detection unit, which includes a resistor R31, a resistor R7 and a capacitor C8. One end of the resistor R31 is connected to the input end of the power modulation module 100, and the other end of the resistor R31 is respectively connected to one end of R7, one end of the capacitor C8 and the control module 600. The other end of the resistor R7 and the other end of the capacitor C8 are both grounded.

[0039] The voltage division detection unit can reduce the voltage level of the zero-crossing signal sampled from the input voltage so that the control module 600 can accurately analyze the zero-crossing signal, and the capacitor C8 can play a filtering role to improve the accuracy of the zero-crossing signal.

[0040] In some embodiments of the present invention, the continuous low-power frequency modulation control circuit further includes a voltage detection module, which is connected to the input end of the power modulation module 100 to detect the input voltage, and the control module 600 is connected to the voltage detection module.

[0041] The voltage detection module can detect the input voltage. When the input voltage is too high, the control module 600 can turn off the switch tube IGBT1 in time to prevent the electromagnetic coil 200 from operating with excessive power and voltage, thereby preventing the electronic components from overvoltage.

[0042] Specifically, the voltage detection module and the zero-crossing detection module 400 may be two separate circuit modules with the same structure. The zero-crossing detection module 400 may also have the function of detecting the input voltage at the input end of the power modulation module 100, thereby simplifying the structure.

[0043] In some embodiments of the present invention, the continuous low-power frequency modulation control circuit includes a synchronous detection module 800, which is respectively connected to both ends of the electromagnetic coil 200 to detect a load signal, and the control module 600 is connected to the synchronous detection module 800.

[0044] The control module 600 can control the on and off of the switch tube IGBT1 to form a pot detection signal. The synchronous detection module 800 detects the voltage signal at both ends of the electromagnetic coil 200, and can analyze and calculate the load frequency as a load signal. According to the load frequency, it can be known whether the electromagnetic coil 200 is coupled with the pot body. When the electromagnetic coil 200 is coupled with the pot body, the control module 600 controls the operation of the switch tube IGBT1 according to the corresponding control strategy, driving the electromagnetic coil 200 to couple and heat the pot body.

[0045] In some embodiments of the present invention, Figure 3 As shown, the synchronous detection module 800 includes a capacitor C14, a resistor R24, a resistor R36, a resistor R18 and a resistor R35, one end of the capacitor C14 is respectively connected to one end of the electromagnetic coil 200 and one end of the resistor R24, the other end of the capacitor C14 is respectively connected to the other end of the electromagnetic coil 200 and one end of the resistor R18, the other end of R24 is respectively connected to one end of the resistor R36 and the control module 600, the other end of the resistor R18 is respectively connected to one end of the resistor R35 and the control module 600, and the other end of the resistor R36 and the other end of the resistor R35 are both grounded.

[0046] In some embodiments of the present invention, Figure 6 As shown, the switch tube temperature detection module 500 includes a thermistor RT1, a resistor R6 and a resistor R8, one end of the resistor R6 is connected to the power supply, the other end of the resistor R6 is respectively connected to one end of the resistor R8, one end of the thermistor RT1 and the control module 600, and the other end of the resistor R8 and the other end of the thermistor RT1 are grounded.

[0047] Resistor R8 and thermistor RT1 are connected in parallel, and then form a resistor voltage divider circuit with resistor R6. Thermistor RT1 is close to switch tube IGBT1. The resistance value of thermistor RT1 changes accordingly according to temperature changes, causing the terminal voltage of one end of thermistor RT1 to change. The control module 600 determines the first temperature signal according to the terminal voltage of one end of thermistor RT1. Since resistor R8 and thermistor RT1 are connected in parallel, it can prevent thermistor RT1 from being too large and causing the terminal voltage to be too high, thereby improving the accuracy of detection.

[0048] In some embodiments of the present invention, Figure 5 As shown, the continuous low-power frequency modulation control circuit further includes a furnace surface temperature detection module 900, which is used to detect a second temperature signal driven by the electromagnetic coil 200 to generate heat, and the control module 600 is connected to the furnace surface temperature detection module 900.

[0049] Generally speaking, the control circuit is used to be set on the induction cooker, and the stove surface temperature detection module 900 can detect the temperature of the panel supporting the pot body, so as to obtain the second temperature signal of the load driven by the electromagnetic coil 200 to heat. When the second temperature signal shows that the temperature is too high, the control module 600 needs to adjust the control strategy in time to reduce the working power of the electromagnetic coil 200.

[0050] Specifically, the furnace surface temperature detection module 900 includes a resistor R16, a resistor R17, a temperature sensor and a capacitor C4, one end of the resistor R17 is connected to the power supply, and the other end of the resistor R17 is respectively connected to one end of the resistor R16, one end of the capacitor C4, the temperature sensor and the control module 600, and the other end of the resistor R16 and the other end of the capacitor C4 are both grounded.

[0051] The temperature sensor can be arranged on the furnace surface to detect the furnace body temperature. The temperature sensor outputs a temperature detection signal to one end of the resistor R16 to form a second temperature signal and provide it to the control module.

[0052] The induction cooker according to the embodiment of the second aspect of the utility model comprises the continuous low-power frequency modulation control circuit disclosed in any one of the above embodiments.

[0053] The induction cooker of the utility model applies the continuous low-power frequency modulation control circuit disclosed in any of the above embodiments to achieve continuous low-power operation with a higher switching frequency while ensuring stable operation of the switch tube, thereby improving the heating effect.

[0054] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0055] Although the embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A continuous low-power frequency modulation control circuit, characterized in that: include: A power modulation module, the input end of the power modulation module is used to connect to the power supply; Solenoid coil; The switch driving module includes only one switch tube IGBT1, the switch tube IGBT1 is connected to the electromagnetic coil to form at least part of the driving power supply branch, and the output end of the power modulation module is connected to the driving power supply branch; A zero-crossing detection module, connected to the power modulation module to detect a zero-crossing signal; A switch tube temperature detection module, used to detect a first temperature signal of the switch tube IGBT1; A control module is respectively connected to the zero-crossing detection module, the switch tube temperature detection module and the controlled end of the switch tube IGBT1. The control module can at least control the switch tube IGBT1 to operate in a first switching mode or in a second switching mode. The control module switches between the first switching mode and the second switching mode according to the first temperature signal. In the first switching mode, the control module modulates the first switching frequency according to the zero-crossing signal and controls the switch tube IGBT1 to operate at the first switching frequency. In the second switching mode, the control module controls the switch tube IGBT1 to operate at a second switching frequency, wherein the first switching frequency is greater than the second switching frequency.

2. A continuous low power frequency modulation control circuit according to claim 1, characterized in that: The zero-crossing detection module includes a voltage division detection unit, which includes a resistor R31, a resistor R7 and a capacitor C8. One end of the resistor R31 is connected to the input end of the power modulation module, and the other end of the resistor R31 is respectively connected to one end of R7, one end of the capacitor C8 and the control module. The other end of the resistor R7 and the other end of the capacitor C8 are both grounded.

3. A continuous low power frequency modulation control circuit according to claim 1, characterized in that: It also includes a voltage detection module, which is connected to the input end of the power modulation module to detect the input voltage, and the control module is connected to the voltage detection module.

4. A continuous low power frequency modulation control circuit according to claim 1, characterized in that: The zero-crossing detection module can also detect the input voltage of the input end of the power modulation module.

5. A continuous low power frequency modulation control circuit according to claim 1, characterized in that: It comprises a synchronous detection module, which is respectively connected to two ends of the electromagnetic coil to detect a load signal, and the control module is connected to the synchronous detection module.

6. A continuous low power frequency modulation control circuit according to claim 5, characterized in that: The synchronous detection module includes a capacitor C14, a resistor R24, a resistor R36, a resistor R18 and a resistor R35. One end of the capacitor C14 is respectively connected to one end of the electromagnetic coil and one end of the resistor R24, the other end of the capacitor C14 is respectively connected to the other end of the electromagnetic coil and one end of the resistor R18, the other end of R24 is respectively connected to one end of the resistor R36 and the control module, the other end of the resistor R18 is respectively connected to one end of the resistor R35 and the control module, and the other end of the resistor R36 and the other end of the resistor R35 are both grounded.

7. The continuous low power frequency modulation control circuit according to claim 1, characterized in that: The switch tube temperature detection module includes a thermistor RT1, a resistor R6 and a resistor R8, one end of the resistor R6 is connected to the power supply, the other end of the resistor R6 is respectively connected to one end of the resistor R8, one end of the thermistor RT1 and the control module, and the other end of the resistor R8 and the other end of the thermistor RT1 are grounded.

8. The continuous low power frequency modulation control circuit according to claim 1, characterized in that: It also includes a furnace surface temperature detection module, which is used to detect a second temperature signal driven by the electromagnetic coil to generate heat, and the control module is connected to the furnace surface temperature detection module.

9. A continuous low power frequency modulation control circuit according to claim 8, characterized in that: The furnace surface temperature detection module includes a temperature sensor, a resistor R16, a resistor R17 and a capacitor C4, one end of the resistor R17 is connected to the power supply, and the other end of the resistor R17 is respectively connected to one end of the resistor R16, one end of the capacitor C4, the temperature sensor and the control module, and the other end of the resistor R16 and the other end of the capacitor C4 are both grounded.

10. An induction cooker, characterized in that: It comprises a continuous low-power frequency modulation control circuit as described in any one of claims 1-9.

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