High-energy-efficiency induction cooker

Abstract

The invention belongs to the technical field of household appliances, and discloses a high-energy-efficiency induction cooker which is characterized in that a silicon carbide MOS (Metal Oxide Semiconductor) tube is introduced as a switching device of a main circuit, and the distance between a heating coil and the upper surface of the induction cooker is optimized; and meanwhile, a zero-voltage switching control strategy that the mains supply voltage and the resonant capacitor voltage are subjected to zero-cross detection and the silicon carbide MOS tube is started at the moment when the mains supply voltage and the resonant capacitor voltage return to zero is adopted, so that the switching loss and the transmission loss of the induction cooker in the energy conversion process are reduced, and the effects of improving the overall energy efficiency and reducing the energy consumption are achieved.

Description

Technical Field

[0001] The present application relates to the technical field of household appliances, and in particular to a high-efficiency induction cooker. Background Art

[0002] As a modern kitchen appliance, the induction cooker operates on the principle of electromagnetic induction. By generating an alternating magnetic field, eddy currents form in the cookware, generating heat and thereby heating water or food. Specifically, the induction cooker's operation involves multiple energy conversion processes: first, mains electricity is converted into high-frequency electromagnetic energy, which is then converted into the internal energy of eddy currents at the bottom of the cookware. Finally, this eddy current energy is converted into the internal energy of the water or food, completing the heating process.

[0003] However, energy loss is inevitable during these multiple energy conversion processes. Existing induction cookers generally suffer from low energy efficiency, resulting in high energy losses. This makes it difficult for most existing induction cookers to achieve ideal energy efficiency levels (most currently achieve only Level 3 efficiency), and even fail to meet basic energy efficiency standards. Consequently, existing induction cookers exhibit significant shortcomings in energy utilization, inconsistent with society's growing demand for energy conservation and environmental protection.

[0004] In view of the above problems, the existing technology is in urgent need of improvement. Summary of the Invention

[0005] The purpose of this application is to provide a high-efficiency induction cooker with the advantages of improving energy efficiency and reducing energy loss.

[0006] The present application provides a high-efficiency induction cooker, comprising a single-chip microcomputer, a main circuit, a driving circuit, a voltage detection module, and a synchronization detection module; The main circuit includes a rectifier circuit, a filter circuit, an LC resonant circuit, and a silicon carbide MOS transistor connected in sequence to form a loop. The rectifier circuit is used to convert AC power into DC power. The LC resonant circuit includes a heating coil and a resonant capacitor. The distance between the heating coil and the upper surface of the induction cooker is 11.5 mm to 12.5 mm. The driving circuit is connected to the single-chip microcomputer and the gate of the silicon carbide MOS transistor, and the single-chip microcomputer is used to control the switch of the silicon carbide MOS transistor through the driving circuit, thereby forming a high-frequency alternating current in the main circuit; The voltage detection module is used to detect the mains voltage, the synchronization detection module is used to detect the voltage of the resonant capacitor, the single-chip microcomputer is used to perform zero-crossing detection on the mains voltage and the voltage of the resonant capacitor, and turn on the silicon carbide MOS tube when the mains voltage and the voltage of the resonant capacitor both return to zero.

[0007] Preferably, the distance between the heating coil and the upper surface of the induction cooker is 11.8 mm to 12.2 mm.

[0008] Preferably, the frequency of the high-frequency alternating current is 20KHz-50KHz.

[0009] Preferably, the driving circuit can output a positive voltage of 18V-22V and a negative voltage of -5V~-3V, and is used to drive the silicon carbide MOS tube to turn on by the positive voltage, and to drive the silicon carbide MOS tube to turn off by the negative voltage.

[0010] Preferably, the single chip microcomputer is also used to first drive the silicon carbide MOS tube with a first preset voltage through the driving circuit within a preset time when the induction cooker is started, and then drive the silicon carbide MOS tube with a preset working voltage; the first preset voltage is lower than the working voltage.

[0011] Preferably, the operating voltage is 18V, the first preset voltage is 9.1V, and the preset time is 2ms.

[0012] Preferably, the high-efficiency induction cooker further includes a cooling fan, a display panel and a voltage conversion circuit. The cooling fan and the display panel are both connected to the single-chip microcomputer. The voltage conversion circuit is used to convert the AC power into direct current of the voltage required for the operation of the single-chip microcomputer, the cooling fan and the display panel, and supply it to the single-chip microcomputer, the cooling fan and the display panel.

[0013] Preferably, the high-efficiency induction cooker further includes a current detection module arranged on the main circuit, which is connected to the single-chip microcomputer and is used to detect the current of the main circuit; the single-chip microcomputer is also used to feedback adjust the power of the induction cooker according to the current, and to perform overcurrent protection when the current is abnormal.

[0014] Preferably, the high-efficiency induction cooker further includes a MOS temperature detection module connected to the single-chip microcomputer, wherein the MOS temperature detection module is used to detect the temperature of the silicon carbide MOS tube. The single-chip microcomputer is also used to reduce the power output of the induction cooker when it is detected that the temperature of the silicon carbide MOS tube is too high, and to perform over-temperature protection when the temperature of the silicon carbide MOS tube is out of control.

[0015] Preferably, the high-efficiency induction cooker further includes a stove surface temperature detection module connected to the single-chip microcomputer, and the stove surface temperature detection module is used to detect the stove surface temperature of the induction cooker; the single-chip microcomputer is also used to perform overheating protection when the stove surface temperature is too high.

[0016] Beneficial effect: The high-efficiency induction cooker provided by the present application introduces a silicon carbide MOS tube as a switching device of the main circuit, and combines it with optimizing the distance between the heating coil and the upper surface of the induction cooker. At the same time, it adopts a zero-voltage switching control strategy of performing zero-crossing detection on the mains voltage and the resonant capacitor voltage and turning on the silicon carbide MOS tube when both are zero, thereby reducing the switching loss and transmission loss of the induction cooker during the energy conversion process, thereby achieving the effect of improving overall energy efficiency and reducing energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the structure of the high-efficiency induction cooker provided in an embodiment of the present application.

[0018] Explanation of reference numbers: 1. Single-chip microcomputer; 2. Main circuit; 3. Drive circuit; 4. Voltage detection module; 5. Synchronous detection module; 201. Rectification circuit; 202. Filter circuit; 203. LC resonant circuit; 204. Silicon carbide MOS tube; 205. Current detection module; 6. Cooling fan; 7. Display panel; 8. Voltage conversion circuit; 801. AC / DC power supply; 802. DC / DC power supply; 9. MOS temperature detection module; 10. Oven surface temperature detection module; 11. Buzzer. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work fall within the scope of protection of the present application.

[0020] It should be noted that similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings. At the same time, in the description of this application, the terms "first", "second", etc. are only used to distinguish the description and should not be understood as indicating or implying relative importance.

[0021] refer to Figure 1 , the present application provides a high energy efficiency induction cooker, comprising a single chip microcomputer 1, a main circuit 2, a driving circuit 3, a voltage detection module 4 and a synchronization detection module 5; The main circuit 2 includes a rectifier circuit 201, a filter circuit 202, an LC resonant circuit 203, and a silicon carbide MOS transistor 204, which are connected in sequence to form a loop. The rectifier circuit 201 is used to convert AC power into DC power. The LC resonant circuit 203 includes a heating coil and a resonant capacitor. The distance between the heating coil and the upper surface of the induction cooker is 11.5 mm to 12.5 mm. The drive circuit 3 is connected to the single-chip microcomputer 1 and the gate of the silicon carbide MOS transistor 204. The single-chip microcomputer 1 is used to control the switching of the silicon carbide MOS transistor 204 through the drive circuit 3, thereby forming a high-frequency alternating current in the main circuit 2; The voltage detection module 4 is used to detect the mains voltage, the synchronization detection module 5 is used to detect the voltage of the resonant capacitor, and the microcontroller 1 is used to perform zero-crossing detection on the mains voltage and the voltage of the resonant capacitor, and turn on the silicon carbide MOS tube 204 when the mains voltage and the voltage of the resonant capacitor are both zero.

[0022] Among them, the single-chip microcomputer 1 is an integrated circuit chip, which integrates a central processing unit, memory, timer / counter and various input / output interfaces. It can be implemented using a microcontroller, embedded processor or dedicated control chip. Its main purpose is to achieve coordinated control and operation management of various functional modules of the induction cooker.

[0023] Among them, the main circuit 2 is the core circuit in the induction cooker responsible for power conversion and high-frequency oscillation. Its main purpose is to convert the input electrical energy into high-frequency electromagnetic energy for the heating coil to generate a magnetic field.

[0024] Among them, the silicon carbide MOS tube 204 is a metal oxide semiconductor field effect transistor made based on silicon carbide material, which is mainly used as a high-frequency switching device to control the current on and off in the main circuit 2 with low loss and high speed, thereby forming high-frequency alternating current.

[0025] Among them, the distance between the heating coil and the upper surface of the induction cooker refers to the vertical spacing between the top plane of the heating coil and the top surface of the induction cooker cooking area (generally the upper surface of the induction cooker panel, which is usually a glass panel or a microcrystalline panel) (this distance is actually the distance between the bottom surface of the pot and the top plane of the heating coil when working). It can be achieved by a mechanical fixed structure or an adjustable support structure, such as fixing it through a bracket or adjusting it through a gasket. Its main purpose is to optimize the magnetic coupling efficiency between the heating coil and the pot and ensure effective energy transfer.

[0026] The drive circuit 3 is a circuit for converting control signals into voltage and current signals sufficient to drive the power switch device (silicon carbide MOS transistor 204) to turn on and off. It can be implemented using a gate drive chip or a discrete component drive circuit, such as the IR2110 driver chip or the TLP250 optocoupler drive circuit. Its main purpose is to provide sufficient drive capability and fast switching speed to ensure reliable operation of the silicon carbide MOS transistor 204.

[0027] Among them, the voltage detection module 4 is a module used to monitor the voltage signal in the circuit in real time. It can be implemented by a resistor voltage divider circuit or a voltage sensor, such as a voltage follower based on an operational amplifier or a Hall effect voltage sensor. Its main purpose is to obtain the real-time value of the mains voltage.

[0028] Among them, the synchronous detection module 5 refers to a module used to detect the voltage of the resonant capacitor, which can be implemented by a resistor voltage divider circuit or a voltage sensor, such as a voltage follower based on an operational amplifier or a Hall effect voltage sensor, which is mainly used to obtain the real-time value of the mains voltage.

[0029] Among them, zero-crossing detection is to judge the AC voltage to determine whether it changes from a positive value to a negative value or from a negative value to a positive value and passes through the zero point. It can be implemented by using a hardware comparator circuit, a software algorithm and ADC sampling. For example, the comparator outputs a square wave signal, and the sign change is judged after sampling by the microcontroller ADC. Its main purpose is to capture the zero point of the voltage signal and provide a timing basis for zero voltage switching.

[0030] For example, the single-chip microcomputer 1 collects the mains voltage and the voltage of the resonant capacitor through the ADC acquisition port in combination with the internal clock signal of the single-chip microcomputer 1 to obtain a digital signal with a precise time stamp, and then performs a zero-crossing test on the digital signal based on a software program (for example, determining the zero-crossing time by linear interpolation) to obtain the time signal when its voltage and current are zero.

[0031] Among them, turning on the silicon carbide MOS tube 204 at the moment when the mains voltage and the voltage of the resonant capacitor both return to zero means triggering the silicon carbide MOS tube 204 to turn on at the moment when the mains voltage and the voltage of the resonant capacitor simultaneously reach zero or close to zero. This can be achieved by adopting a zero voltage switching (ZVS) control strategy or a zero current switching (ZCS) control strategy, etc., which is mainly to reduce switching losses and improve the overall energy efficiency of the induction cooker.

[0032] The core innovation of this application lies in the introduction of a silicon carbide MOS tube 204 as a switching device in the main circuit 2, combined with the optimization of the distance between the heating coil and the upper surface of the induction cooker, and the adoption of a zero-voltage switching control strategy that performs zero-crossing detection on the mains voltage and the resonant capacitor voltage and turns on the silicon carbide MOS tube 204 when both return to zero, thereby reducing the switching loss and transmission loss of the induction cooker during the energy conversion process, thereby achieving the effect of improving the overall energy efficiency (which can reach level 1 energy efficiency) and reducing energy consumption.

[0033] Specifically, the operation of the induction cooker is controlled by the single-chip microcomputer 1. When the induction cooker is started, the mains electricity is first converted to direct current (DC) by the rectifier circuit 201. It is then smoothed by the filter circuit 202, providing a stable DC power source for subsequent energy conversion. This DC power enters the main circuit 2, which includes an LC resonant circuit 203 and a silicon carbide MOS transistor 204. The single-chip microcomputer 1 sends a control signal to the gate of the silicon carbide MOS transistor 204 via the driver circuit 3, controlling its high-speed switching. The switching of the silicon carbide MOS transistor 204 causes the DC power to be chopped in the LC resonant circuit 203, thereby generating high-frequency alternating current (AC). This high-frequency AC power drives the heating coil in the LC resonant circuit 203, generating a high-frequency alternating magnetic field. This magnetic field penetrates the upper surface of the induction cooker, inducing eddy currents at the bottom of any pot placed on it. The heat generated by the eddy currents is used to heat the pot.

[0034] In order to optimize energy efficiency, the induction cooker introduces a control mechanism. The voltage detection module 4 monitors the mains voltage in real time, and the synchronous detection module 5 monitors the voltage of the resonant capacitor in the LC resonant circuit 203 in real time. The single-chip microcomputer 1 receives this voltage information and performs zero-crossing detection on the mains voltage and the resonant capacitor voltage. When it detects that the mains voltage and the resonant capacitor voltage are both zero, the single-chip microcomputer 1 immediately turns on the silicon carbide MOS tube 204 through the driving circuit 3. This zero-voltage switching technology reduces the loss of the silicon carbide MOS tube 204 during the switching process, because the device is turned on when the voltage is zero, avoiding transient losses caused by the simultaneous existence of high voltage and high current. In addition, the heating coil and the upper surface of the induction cooker are maintained within a specific distance range, ensuring the magnetic coupling efficiency between the heating coil and the pot, and reducing energy loss during transmission. Through these synergistic effects, the induction cooker achieves improved energy conversion efficiency and reduced operating losses.

[0035] Through the above solution, the induction cooker of this application reduces switching losses during energy conversion due to the low switching loss characteristics of silicon carbide MOS transistor 204 and the implementation of a zero-voltage switching control strategy. At the same time, optimizing the distance between the heating coil and the upper surface of the induction cooker improves magnetic coupling efficiency and reduces energy loss during transmission. These measures work together to improve the overall energy conversion efficiency of the induction cooker, thereby resolving the problems of low energy efficiency and high energy loss in existing induction cookers and achieving energy-saving operation.

[0036] In addition, by monitoring the mains voltage in real time through the voltage detection module 4, the surge phenomenon of the power grid can be detected in time. The microcontroller 1 can cut off the power output when a surge occurs in the power grid to prevent the silicon carbide MOS tube 204 from being broken down due to excessive voltage, thereby protecting the induction cooker.

[0037] In fact, the above-mentioned distance between the heating coil and the upper surface of the induction cooker is 11.5mm-12.5mm, which is a range set based on the deviation of the coil flatness consistency. When the coil flatness consistency is high enough, the range can be narrowed to 11.8mm-12.2mm.

[0038] By precisely limiting the distance between the heating coil and the top surface of the induction cooker to an optimized range of 11.8mm to 12.2mm, this application significantly improves the energy conversion efficiency of the induction cooker. This precise distance control ensures that the magnetic field is more effectively coupled to the bottom of the cookware, minimizing energy loss during transmission. Therefore, this application effectively addresses the poor energy efficiency of induction cookers in the prior art, enabling the induction cooker to more efficiently utilize electrical energy during the heating process, thereby improving its overall energy efficiency.

[0039] In actual use, high-frequency electromagnetic energy creates a significant skin effect on eddy currents. If the cookware is too thin or too thick, significant electromagnetic energy is wasted, leading to increased losses. Experiments have shown that optimal energy savings are achieved when the cookware bottom thickness is between 0.5mm and 1.5mm. Therefore, in some optional embodiments, the high-efficiency induction cooker may further include a matching cookware with a bottom thickness of 0.5mm to 1.5mm.

[0040] In some of the aforementioned embodiments of the present application, it is proposed that a single-chip microcomputer 1 controls a drive circuit 3 and a silicon carbide MOS transistor 204 to generate a high-frequency alternating current in a main circuit 2 to achieve the heating function of an induction cooker. However, during this implementation, if the frequency of the high-frequency alternating current is improperly selected, the energy efficiency of the induction cooker may fail to achieve the desired high energy efficiency target. At the same time, audible noise may be generated, component losses may increase, and electromagnetic compatibility issues may arise, thereby affecting the overall performance of the induction cooker and the user experience.

[0041] In order to solve the above problems, the present application further optimizes and limits the frequency of the high-frequency alternating current generated in the main circuit 2. Specifically, the frequency of the high-frequency alternating current can be set to 20KHz to 50KHz.

[0042] This frequency range is designed to optimize the induction cooker's performance, improve energy efficiency, reduce noise, and ensure stable component operation. Setting the frequency above 20 kHz effectively avoids the human ear's audible range, significantly reducing noise generated during operation and improving the user experience. Setting the frequency below 50 kHz helps balance switching losses and heating efficiency. Excessively high frequencies increase switching losses in SiC MOS transistor 204, impacting overall energy efficiency. Within this range, SiC MOS transistor 204 operates in its high-efficiency range while maintaining a sufficient heating frequency for fast and efficient energy conversion. This frequency selection is based on a comprehensive consideration of the induction cooker's operating principle, component characteristics, energy efficiency requirements, and user experience, aiming to achieve an optimal balance between high energy efficiency, low noise, and high reliability. Microcontroller 1 precisely controls the switching frequency of SiC MOS transistor 204 via driver circuit 3, ensuring stable operation within a preset range of 20 kHz to 50 kHz. This precise frequency control, combined with LC resonant circuit 203 in main circuit 2, ensures efficient resonant heating while avoiding unnecessary energy loss and negative effects. It is through this refined management of the high-frequency AC power frequency that the induction cooker solution of this application can achieve an optimized balance of high energy efficiency, low noise and high reliability.

[0043] In some preferred embodiments, the driving circuit 3 can output a positive voltage of 18V-22V and a negative voltage of -5V~-3V, and is used to drive the silicon carbide MOS tube 204 to turn on by the positive voltage and to drive the silicon carbide MOS tube 204 to turn off by the negative voltage.

[0044] Here, a positive voltage refers to a positive voltage output to the gate of the silicon carbide MOS transistor 204, which can be achieved by, but not limited to, a boost converter, a charge pump, or an independent DC power supply. A negative voltage refers to a negative voltage output to the gate of the silicon carbide MOS transistor 204, which can be achieved by, but not limited to, a buck converter, an inverter, or an independent negative voltage power supply.

[0045] Based on the configuration of the aforementioned drive circuit 3, this solution aims to optimize the switching characteristics of the SiC MOS transistor 204 by precisely limiting the output voltage of the drive circuit 3, thereby improving the energy efficiency and operational stability of the induction cooker. Specifically, the drive circuit 3 can output a positive voltage of 18V-22V to ensure that the SiC MOS transistor 204 receives a sufficiently high gate voltage when turned on. Compared to traditional silicon-based MOS transistors, the SiC MOS transistor 204 typically requires a higher gate drive voltage to fully turn on and achieve the lowest on-resistance. Providing a positive voltage range of 18V-22V enables the SiC MOS transistor 204 to fully saturate and conduct, significantly reducing its conduction losses, thereby improving the overall efficiency of the induction cooker. Simultaneously, the drive circuit 3 can output a negative voltage of -5V to -3V, which is used to drive the SiC MOS transistor 204 to turn off. During the shutdown process of the SiC MOS transistor 204, particularly in high-frequency applications, the Miller effect may cause the gate voltage to plateau, slowing the shutdown speed. By providing a negative voltage, the driver circuit 3 can quickly and forcefully lower the gate voltage of the silicon carbide MOS transistor 204 to below its threshold voltage, or even to a negative value, thereby accelerating the shutdown process, effectively suppressing the Miller effect, and reducing shutdown losses. The negative voltage range of -5V to -3V ensures fast and reliable shutdown while avoiding potential damage to the gate insulation layer caused by excessive negative voltage, thus balancing performance and reliability. This precise positive and negative voltage drive strategy enables the silicon carbide MOS transistor 204 to quickly and completely transition from the off state to the on state, and quickly and reliably transition from the on state to the off state. This provides a stable foundation for the microcontroller 1 to control the switching of the silicon carbide MOS transistor 204 through the driver circuit 3, thereby forming a high-frequency alternating current in the main circuit 2. By optimizing the switching speed and efficiency of the silicon carbide MOS transistor 204, the conduction delay and loss during the switching process can be effectively reduced, avoiding the risk of cross conduction and switching losses caused by incomplete shutdown or slow shutdown speed. This not only fully utilizes the advantages of the silicon carbide MOS tube 204 in high-frequency applications, but also directly improves the generation quality and overall energy efficiency of high-frequency alternating current in the induction cooker main circuit 2, and is a key technical means to achieve high-efficiency induction cookers.

[0046] In some embodiments, the single chip computer 1 is also used to first drive the silicon carbide MOS tube 204 with a first preset voltage through the driving circuit 3 within a preset time when the induction cooker is started, and then drive the silicon carbide MOS tube 204 with a preset working voltage; wherein the first preset voltage is lower than the working voltage.

[0047] The preset time refers to the duration during which the silicon carbide MOS tube 204 is driven at a lower voltage at the initial start-up of the induction cooker. The preset time can be determined based on the characteristics of the silicon carbide MOS tube 204, the power level of the induction cooker, and the desired startup smoothness. For example, it can be set to several milliseconds to tens of milliseconds, or a suitable time window can be obtained through experimental optimization.

[0048] The first preset voltage refers to the initial voltage used to drive the silicon carbide MOS transistor 204 within a preset time. The first preset voltage can be selected based on the turn-on threshold voltage and safe operating area of ​​the silicon carbide MOS transistor 204. For example, the first preset voltage can be set to 1.5 to 2 times the turn-on threshold voltage of the silicon carbide MOS transistor 204, or to a fixed value lower than the normal operating voltage.

[0049] Among them, the preset operating voltage refers to the voltage used to continuously drive the silicon carbide MOS tube 204 after the induction cooker enters the normal working state. It can be determined based on the saturation conduction characteristics of the silicon carbide MOS tube 204 and the rated power requirement of the induction cooker. For example, it can be set to a value in the range of 18V to 22V, or set to a specific voltage value according to system design requirements.

[0050] This application effectively addresses the impact that may be caused to the silicon carbide MOS transistor at the moment of induction cooker startup by introducing a phased driving voltage strategy. When the induction cooker starts, the single-chip microcomputer 1 first applies a first preset voltage to the silicon carbide MOS transistor 204 through the driving circuit 3. Because the first preset voltage is set to be lower than the subsequent operating voltage, the silicon carbide MOS transistor 204 will not be fully turned on immediately at the initial startup, but will start operating at a controlled, lower current level. This low-voltage drive continues for a preset time, allowing the LC resonant circuit 203 and silicon carbide MOS transistor 204 in the main circuit 2 to gradually establish a stable operating state, effectively limiting the peak value of the starting current, thereby avoiding excessive instantaneous current causing thermal stress or electrical stress damage to the silicon carbide MOS transistor 204. After the preset time expires, the single-chip microcomputer 1 smoothly switches the driving voltage from the first preset voltage to the preset operating voltage. At this time, the silicon carbide MOS transistor 204 will be fully turned on, allowing the main circuit 2 to generate high-frequency alternating current, thereby driving the heating coil to generate electromagnetic induction heating. This switching process is performed after the system has achieved initial stability and current and voltage fluctuations have been effectively suppressed, ensuring a smooth transition from startup to normal operation. This phased drive method combines the microcontroller's 1 precise control of the drive circuit 3 with the drive circuit 3's ability to output a positive voltage to turn on the silicon carbide MOS transistor 204, achieving a soft start for the induction cooker. This not only protects the silicon carbide MOS transistor 204, the core power device, and extends its service life, but also significantly improves the induction cooker's startup reliability and stability under various load conditions. By avoiding the shock of startup, the system can enter the operating state more stably, reducing the risk of startup failure or triggering protection mechanisms, and also helping to reduce noise during the startup process.

[0051] For example, in some possible implementations, the operating voltage is 18V, the first preset voltage is 9.1V, and the preset time is 2ms.

[0052] Specifically, the operating voltage driving the SiC MOS transistor 204 during normal operation of the induction cooker is set to 18V. This voltage ensures that the SiC MOS transistor 204 exhibits a low on-resistance when fully on, thereby reducing energy loss and improving the operating efficiency of the induction cooker. During the initial startup of the induction cooker, the microcontroller 1 applies a low first preset voltage of 9.1V via the driver circuit 3. This 9.1V voltage, lower than the normal operating voltage, provides an initial drive for the SiC MOS transistor 204, allowing it to gradually begin conducting and avoiding the high current surge and voltage spikes that may occur during startup. This gradual voltage application protects the SiC MOS transistor 204 and helps extend its service life. Furthermore, the duration of the first preset voltage (9.1V) is set to 2ms. This 2ms duration is a proven value that ensures sufficient time for the SiC MOS transistor 204 to complete the soft-start process, gradually transitioning from a fully off state to a partially on state, while preventing excessive delays in the induction cooker entering normal operating mode. This time control further reduces transient losses and electromagnetic interference during the startup process, thereby ensuring the smoothness and reliability of the induction cooker startup. By applying these voltage and time parameters to the startup control strategy of the induction cooker, the present application can solve the impact and loss problems that may occur during the startup process, and improve the overall energy efficiency performance and system stability of the induction cooker. This parameter limitation enables the soft start mechanism to perform its function, ensuring that the silicon carbide MOS tube 204 is in a suitable state throughout the entire operating cycle, thereby providing a basis for the efficient and stable operation of the induction cooker.

[0053] In some embodiments, see Figure 1 The high-efficiency induction cooker also includes a cooling fan 6, a display panel 7 and a voltage conversion circuit 8. The cooling fan 6 and the display panel 7 are both connected to the single-chip microcomputer 1. The voltage conversion circuit 8 is used to convert the mains power into direct current of the voltage required for the operation of the single-chip microcomputer 1, the cooling fan 6 and the display panel 7, and supply it to the single-chip microcomputer 1, the cooling fan 6 and the display panel 7.

[0054] The heat dissipation fan 6 may be an axial flow fan, a centrifugal fan, a cross flow fan or the like.

[0055] Among them, the display panel 7 is a control panel including a display screen such as a liquid crystal display (LCD), a light emitting diode display (LED) or an organic light emitting diode display (OLED), and is used to set the mode, power, timing duration, etc. of the induction cooker, and to display the working status information of the induction cooker (such as the current mode, current power, current pot temperature, remaining timing duration, etc.), and to display a specific fault code when a fault occurs.

[0056] Among them, the voltage conversion circuit 8 is a circuit used to convert one voltage form into another voltage form, usually used to convert alternating current into direct current, or convert high voltage into low voltage, which can be implemented in the form of a switching power supply (such as a flyback converter, a buck converter) or a linear regulator.

[0057] By introducing the cooling fan 6, the heat generated during operation within the induction cooker can be effectively dissipated, particularly cooling high-heat-generating components such as the silicon carbide MOS transistor 204. This prevents unstable performance, shortened lifespan, or damage to components due to overheating, thereby improving the long-term operational reliability and safety of the induction cooker. By providing a display panel 7, the user can intuitively view information such as the induction cooker's current operating status and setting parameters, greatly enhancing the convenience and intuitiveness of user operation. This allows the user to clearly understand the induction cooker's operating status and make corresponding settings, improving the human-computer interaction experience. By configuring the voltage conversion circuit 8, the mains power can be converted into the stable DC voltage required for the operation of the single-chip microcomputer 1, the cooling fan 6, and the display panel 7, and supplied to these components. This ensures that these key auxiliary components receive a stable and reliable power supply, thereby guaranteeing the precise control of the induction cooker by the single-chip microcomputer 1, the normal operation of the cooling fan 6, and the correct display on the display panel 7. This is the fundamental guarantee for the normal operation of the entire induction cooker system. In summary, the solution of the present application enables the induction cooker to not only have efficient heating capabilities, but also take into account operational stability, safety and user convenience, providing a more complete and practical induction cooker product.

[0058] For example, in some embodiments, Figure 1 As shown, the operating voltage of the cooling fan 6 is 18V, the operating voltage of the microcontroller 1 and the display panel 7 is 5V, and the voltage conversion circuit 8 includes an AC / DC power supply 801 and a DC / DC power supply 802; the AC / DC power supply 801 is used to convert the mains power into 18V DC power and supply it to the cooling fan 6 and the DC / DC power supply 802; the DC / DC power supply 802 is used to convert the 18V DC power into 5V DC power and supply it to the microcontroller 1 and the display panel 7.

[0059] Among them, the AC / DC power supply 801 can also be used to provide 18V DC power to the drive circuit 3. For example, the AC / DC power supply 801 is directly connected to the drive circuit 3 through a wire to supply power to the drive circuit 3, or the 18V DC power is supplied to the drive circuit 3 through the internal circuit of the microcontroller 1.

[0060] Further, see Figure 1The high-efficiency induction cooker may further include a current detection module 205 arranged on the main circuit 2. The current detection module 205 is connected to the single-chip computer 1 and is used to detect the current of the main circuit 2; the single-chip computer 1 is also used to feedback adjust the power of the induction cooker according to the current of the main circuit 2, and to perform overcurrent protection when the current is abnormal.

[0061] The current detection module 205 is a device for obtaining the current in the circuit in real time, and can be implemented by using a shunt resistor, a Hall current sensor, a current transformer or a Rogowski coil.

[0062] The present application introduces a current detection module 205 into the main circuit 2 of the induction cooker, so that the current of the main circuit 2 can be detected in real time. After the single-chip microcomputer 1 receives the real-time current data provided by the current detection module 205, it can perform feedback adjustment on the power of the induction cooker based on this data. Specifically, the single-chip microcomputer 1 can compare the actual current value detected with the preset power target, and dynamically adjust the driving parameters of the silicon carbide MOS tube 204 based on this difference, such as adjusting its switching frequency or duty cycle, to ensure that the output power of the induction cooker can accurately meet the requirements set by the user and adapt to different cooking needs and load changes. This power regulation mechanism based on current feedback makes the power output of the induction cooker more stable and accurate, improving the cooking effect and energy utilization efficiency.

[0063] Furthermore, the microcontroller 1 can utilize data provided by the current detection module 205 for overcurrent protection. When an abnormality such as a short circuit, excessive load, or component failure occurs in the main circuit 2, causing a sharp increase in current, the current detection module 205 immediately detects this abnormality and feeds this information back to the microcontroller 1. Upon receiving the abnormal current signal, the microcontroller 1 quickly triggers a protection mechanism, such as immediately shutting down the silicon carbide MOS transistor 204 or significantly reducing power output. This effectively prevents excessive current from causing permanent damage to core components such as the silicon carbide MOS transistor 204 and the LC resonant circuit 203.

[0064] By combining the current detection module 205 with the single-chip microcomputer 1, the present application further realizes real-time monitoring and precise control of the main circuit current on the basis of the original high energy efficiency achieved by voltage zero-crossing detection. This enables the induction cooker to not only maintain high energy efficiency operation, but also to perform dynamic power adjustment according to the actual load and power supply fluctuations, ensuring the stability and accuracy of power output. At the same time, in the case of abnormal current, the system can respond quickly and activate the protection mechanism, effectively avoiding damage to key components, significantly enhancing the reliability and service life of the induction cooker, and ensuring the user's operational safety. This solution that combines voltage zero-crossing control with current feedback regulation and protection forms a more complete and robust induction cooker control system, enabling it to operate stably, safely and efficiently in a complex and changing usage environment.

[0065] Alternatively, see Figure 1 The high-efficiency induction cooker may further include a MOS temperature detection module 9 connected to the single-chip computer 1. The MOS temperature detection module 9 is used to detect the temperature of the silicon carbide MOS tube 204. The single-chip computer 1 is also used to reduce the power output of the induction cooker when it is detected that the temperature of the silicon carbide MOS tube 204 is too high, and to perform over-temperature protection when the temperature of the silicon carbide MOS tube 204 is out of control.

[0066] Among them, the MOS temperature detection module 9 is a device for sensing and quantifying the operating temperature of the silicon carbide MOS tube 204. It can be implemented by using a thermistor, a thermocouple or an integrated temperature sensor. These sensors are usually arranged near the heat sink or package of the silicon carbide MOS tube 204 to obtain temperature data.

[0067] By introducing a temperature monitoring and protection mechanism for the SiC MOS transistor 204, this solution effectively addresses the issue of performance degradation, shortened lifespan, or even damage to the SiC MOS transistor 204 during operation, potentially caused by overheating. This improves the reliability and safety of the induction cooker. Specifically, this solution incorporates a MOS temperature detection module 9 connected to the single-chip microcomputer 1, which accurately and in real time detects the temperature of the SiC MOS transistor 204. This real-time detection capability is fundamental to effective temperature management, ensuring that the single-chip microcomputer 1 can promptly obtain operating status information on key power components. When the MOS temperature detection module 9 detects that the temperature of the SiC MOS transistor 204 is excessively high (e.g., above a preset temperature threshold, referred to as the danger threshold below), the single-chip microcomputer 1 proactively reduces the power output of the induction cooker according to a preset strategy. This power regulation mechanism effectively controls the temperature rise of the SiC MOS transistor 204 by reducing its load and heat generation, even before the temperature reaches the danger threshold, thereby preventing continued overheating and protecting the components and maintaining stable operation of the induction cooker. If, after taking power reduction measures, the temperature of the silicon carbide MOS transistor 204 continues to rise, even reaching a dangerous level of loss of control, the single-chip microcontroller 1 can implement a higher-level over-temperature protection measure, such as immediately stopping the operation of the induction cooker. This hierarchical protection strategy, which first performs soft protection by reducing power and then performs hard protection in extreme cases, provides comprehensive and sophisticated temperature management for the silicon carbide MOS transistor 204, enhancing the long-term reliability and safety of the induction cooker. Given that the main circuit 2 of the induction cooker uses silicon carbide MOS transistor 204 to generate high-frequency alternating current to achieve high energy efficiency, this means that the silicon carbide MOS transistor 204 will withstand a higher power load and generate heat during operation. The temperature detection and protection mechanism of this solution is closely integrated with this high-efficiency main circuit to form a complete system. By real-time monitoring and graded protection of the temperature of the silicon carbide MOS transistor 204, this solution ensures that the silicon carbide MOS transistor 204 can operate within a safe temperature range even during long-term high-power operation or abnormal conditions, thereby fully leveraging its high energy efficiency advantage. At the same time, it avoids performance degradation or damage caused by overheating, ensuring the long-term stable operation and safe use of the induction cooker.

[0068] Alternatively, see Figure 1 The high-efficiency induction cooker may further include a stove surface temperature detection module 10 connected to the single-chip microcomputer 1. The stove surface temperature detection module 10 is used to detect the stove surface temperature of the induction cooker (i.e., the temperature of the induction cooker panel, which is approximately the temperature of the bottom of the pot); the single-chip microcomputer 1 is also used to perform overheating protection when the stove surface temperature is too high.

[0069] The stove surface temperature detection module 10 is a device for sensing the temperature of the induction cooker surface, and can be implemented by a thermistor, a thermocouple, or an infrared temperature sensor.

[0070] Among them, overheat protection refers to a series of measures taken by the system when the detected furnace surface temperature exceeds the safety threshold, which may include reducing power output, issuing sound and light alarms, or cutting off power supply.

[0071] The present application introduces a stove surface temperature detection module 10 and connects it to the single-chip microcomputer 1. After receiving the temperature data fed back by the stove surface temperature detection module 10, the single-chip microcomputer 1 can make a judgment based on the safety threshold. When it is detected that the stove surface temperature is too high (generally due to dry burning or equipment failure), the single-chip microcomputer 1 will start the overheating protection mechanism, such as reducing power output, sounding an alarm or cutting off the power supply to prevent the stove surface temperature from continuing to rise. In this way, the single-chip microcomputer 1 can not only control the silicon carbide MOS tube 204 to improve energy efficiency, but also monitor and respond to the safety status of the induction cooker based on the data provided by the stove surface temperature detection module 10. This combination allows the induction cooker to maintain high energy efficiency while improving its safety and reliability, avoiding the safety risks caused by dry burning or the risk of damage to the induction cooker components due to overheating.

[0072] In some embodiments, see Figure 1 The high-efficiency induction cooker may further include a buzzer 11 connected to the single-chip computer 1. The buzzer 11 is used to issue a sound alarm signal when an abnormality occurs in the induction cooker (such as the temperature of the silicon carbide MOS tube 204 is too high, the temperature of the silicon carbide MOS tube 204 is out of control, the temperature of the stove surface is too high, etc.).

[0073] In some possible embodiments, the heating coil is arranged in the induction cooker through a lifting mechanism, and the lifting mechanism is used to adjust the height of the heating coil (the height adjustment range corresponds to the distance variation range between the heating coil and the upper surface of the induction cooker, which includes at least 11.5mm-12.5mm); the microcontroller 1 is also used to control the lifting mechanism to adjust the height of the heating coil according to the current of the main circuit 2, so as to optimize the distance between the heating coil and the upper surface of the induction cooker.

[0074] The heating coil is positioned within the induction cooker via a lifting mechanism that adjusts its height. This technical approach introduces a lifting mechanism that allows the previously fixed heating coil to be moved vertically. This provides the physical basis for dynamically adjusting the distance between the heating coil and the cooker's top surface, breaking through the limitations of traditional induction cookers' fixed heating coil positions and creating conditions for optimizing electromagnetic coupling efficiency.

[0075] The lifting mechanism can be implemented in a variety of ways. For example, a stepper motor can be used to drive the heating coil up and down by rotating the screw. Alternatively, a DC motor can be used in conjunction with a rack and pinion mechanism to raise and lower the heating coil. Alternatively, an electromagnetic drive mechanism can be used to control the floating height of the heating coil through electromagnetic force. The heating coil can be fixed to a movable platform connected to the lifting mechanism, or the heating coil itself can be designed to be directly driven by the lifting mechanism.

[0076] The current of the main circuit 2 is detected by the current detection module 205, and the single chip microcomputer 1 drives the motor of the lifting mechanism through a control signal, such as a PWM signal or a digital signal, to move it upward or downward.

[0077] To optimize the distance between the heating coil and the upper surface of the induction cooker, the microcontroller 1 can execute an optimization algorithm. For example, while the induction cooker is operating, the microcontroller 1 can periodically fine-tune the height of the heating coil while simultaneously monitoring the current changes in the main circuit 2. The optimal distance is considered reached when the current reaches a peak or when the current fluctuation is minimized and the efficiency is highest at a specific power output. A current-height comparison table can also be preset to find the corresponding optimal height based on the detected current value. Alternatively, the microcontroller 1 can execute a search algorithm, such as a hill climbing algorithm, to gradually approach the optimal coupling point by adjusting the height in small steps and evaluating the current response after each adjustment. Furthermore, a pot recognition function can be combined. For example, by detecting the impact of the material and size of the cookware on the current, the microcontroller 1 can adjust to a preset optimal height range based on the characteristics of different cookware.

[0078] Building on existing technology, this solution utilizes the main circuit current detected by current detection module 205 as a basis for determining the operating status and energy conversion efficiency of the induction cooker. Through real-time current monitoring and analysis by microcontroller 1, it can determine whether the current coupling between the heating coil and the cookware is optimal. When current fluctuations or a drop in efficiency are detected, indicating suboptimal coupling efficiency, microcontroller 1 issues a command to drive the lifting mechanism to adjust the height of the heating coil. This dynamic adjustment based on current feedback ensures that the distance between the heating coil and the upper surface of the induction cooker (i.e., the bottom of the cookware) is always maintained at the optimal level, minimizing energy loss and improving the overall energy efficiency of the induction cooker. This resolves the issue of achieving optimal coupling efficiency at a fixed distance.

[0079] In summary, the present application uses a silicon carbide MOS tube 204 to replace the IGBT device commonly used in traditional induction cookers. Compared with the IGBT device, the silicon carbide MOS tube 204 has a lower on-state internal resistance and a higher temperature resistance. The internal resistance can be maintained at a low state under high temperature conditions. It also has a fast and high-frequency switching capability, ensuring a higher high-frequency electromagnetic energy conversion efficiency and reducing energy loss. In addition, when driving the switch of the silicon carbide MOS tube 204, a positive voltage of 18V-22V is used to drive it open, and a negative voltage of -5V~-3V is used to drive it closed. The positive voltage range helps to fully open the silicon carbide MOS tube 204 and reduce the impact of the on-state internal resistance. The negative voltage range effectively turns off the silicon carbide MOS tube 204 and reduces the impact of leakage, thereby further reducing energy loss. Furthermore, the high-frequency driving mode of 20KHz to 50KHz can achieve efficient high-frequency electromagnetic energy conversion, thereby reducing the generation of losses. At the same time, by optimizing the distance between the heating coil and the top surface of the induction cooker, the efficiency of converting high-frequency electromagnetic energy into eddy current internal energy can be improved, further reducing energy loss. This energy reduction effect is even greater when used with cookware with a bottom thickness of 0.5mm-1.5mm. The synergistic effect of these key energy-saving designs significantly reduces the overall energy loss of the induction cooker. Even with the most common three-level energy-efficiency coils (which are relatively low-cost, typically 5-7 yuan), high energy efficiency (level 1 efficiency) can be achieved. Compared to the energy-efficiency improvement approach of using high-efficiency coils (which typically use higher-performance coil materials, adopt denser winding methods, and add high-permeability magnets, resulting in a higher cost of 30-50 yuan), this solution achieves high energy efficiency while significantly reducing costs.

[0080] The above description is merely an embodiment of the present application and is not intended to limit the scope of protection of the present application. For those skilled in the art, various modifications and variations of the present application are possible. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A high energy efficiency induction cooker, characterized in that: It includes a single chip microcomputer (1), a main circuit (2), a driving circuit (3), a voltage detection module (4) and a synchronization detection module (5); The main circuit (2) comprises a rectifier circuit (201), a filter circuit (202), an LC resonant circuit (203), and a silicon carbide MOS tube (204) connected in sequence to form a loop, the rectifier circuit (201) being used to convert the mains electricity into direct current, the LC resonant circuit (203) comprising a heating coil and a resonant capacitor, and the distance between the heating coil and the upper surface of the induction cooker is 11.5 mm to 12.5 mm; The drive circuit (3) is connected to the single chip microcomputer (1) and the gate of the silicon carbide MOS transistor (204), and the single chip microcomputer (1) is used to control the switch of the silicon carbide MOS transistor (204) through the drive circuit (3), thereby forming a high-frequency alternating current in the main circuit (2); The voltage detection module (4) is used to detect the mains voltage, the synchronization detection module (5) is used to detect the voltage of the resonant capacitor, and the single chip computer (1) is used to perform zero-crossing detection on the mains voltage and the voltage of the resonant capacitor, and to turn on the silicon carbide MOS tube (204) when the mains voltage and the voltage of the resonant capacitor both return to zero.

2. The high energy efficiency induction cooker according to claim 1, characterized in that: The distance between the heating coil and the upper surface of the induction cooker is 11.8 mm to 12.2 mm.

3. The high energy efficiency induction cooker according to claim 1, characterized in that: The frequency of the high-frequency alternating current is 20KHz-50KHz.

4. The high energy efficiency induction cooker according to claim 1, characterized in that: The driving circuit (3) is capable of outputting a positive voltage of 18V-22V and a negative voltage of -5V--3V, and is used to drive the silicon carbide MOS tube (204) to open by the positive voltage, and to drive the silicon carbide MOS tube (204) to close by the negative voltage.

5. The high energy efficiency induction cooker according to claim 4, characterized in that: The single chip computer (1) is further configured to, when the induction cooker is started, first drive the silicon carbide MOS tube (204) at a first preset voltage via the drive circuit (3) within a preset time, and subsequently drive the silicon carbide MOS tube (204) at a preset operating voltage; the first preset voltage being lower than the operating voltage.

6. The high energy efficiency induction cooker according to claim 5, characterized in that: The operating voltage is 18V, the first preset voltage is 9.1V, and the preset time is 2ms.

7. The high energy efficiency induction cooker according to claim 1, characterized in that: The device further comprises a cooling fan (6), a display panel (7) and a voltage conversion circuit (8), wherein the cooling fan (6) and the display panel (7) are both connected to the single-chip microcomputer (1), and the voltage conversion circuit (8) is used to convert the mains electricity into direct current of a voltage required for the operation of the single-chip microcomputer (1), the cooling fan (6) and the display panel (7), and supply the direct current to the single-chip microcomputer (1), the cooling fan (6) and the display panel (7).

8. The high energy efficiency induction cooker according to claim 1, characterized in that: The invention also includes a current detection module (205) provided on the main circuit (2), the current detection module (205) being connected to the single chip computer (1) and used for detecting the current of the main circuit (2); the single chip computer (1) is also used for performing feedback adjustment on the power of the induction cooker according to the current, and performing overcurrent protection when the current is abnormal.

9. The high energy efficiency induction cooker according to claim 1, characterized in that: The invention also includes a MOS temperature detection module (9) connected to the single-chip computer (1), wherein the MOS temperature detection module (9) is used to detect the temperature of the silicon carbide MOS tube (204). The single-chip computer (1) is also used to reduce the power output of the induction cooker when it is detected that the temperature of the silicon carbide MOS tube (204) is too high, and to perform over-temperature protection when the temperature of the silicon carbide MOS tube (204) is out of control.

10. The high energy efficiency induction cooker according to claim 1, characterized in that: It also includes a furnace surface temperature detection module (10) connected to the single chip computer (1), and the furnace surface temperature detection module (10) is used to detect the furnace surface temperature of the induction cooker; the single chip computer (1) is also used to perform overheating protection when the furnace surface temperature is too high.

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