Heating device and low-power continuous heating method

Abstract

A heating device and a low power continuous heating method are disclosed. The heating device includes a resonance module, a power switch module, a voltage rate of change control module, a power supply module, a microcontroller module, a voltage detection module, and a power switch voltage detection and counting module. The resonance module is used to perform electromagnetic induction to generate energy. The power switch module is used to cause the resonance module to perform electromagnetic induction to generate energy. The voltage rate of change control module is used to adjust an input voltage of the power switch module according to a voltage rate of change. The microcontroller module is used to output a control signal to control the voltage rate of change control module to adjust the voltage rate of change. The voltage detection module is used to detect the input voltage of the power switch module to trigger the microcontroller module to adjust the control signal.

Description

Technical Field

[0001] This invention relates to a heating device and a low-power continuous heating method, particularly an IH type heating device. Background Technology

[0002] Traditional single-tube induction cookers typically operate at power levels above 1000 watts (W). Their advantages include low-cost circuitry and the ability to perform continuous high-power heating. However, they cannot achieve continuous low-power heating. Generally, when a traditional single-tube induction cooker is set to "low power" output mode, it is still operating in a high-power mode using a single drive voltage. The power is reduced by intermittently switching the heating on and off within a fixed cycle, thus lowering the average power of the cooker to a low level. However, this intermittent heating method is not only inefficient but also fails to achieve the gentle, even heating effect of traditional cooktops. Furthermore, the intermittent heating method causes the resonant circuit of the traditional single-tube induction cooker to experience a momentary electromagnetic force at the beginning of each heating cycle. This force causes the cookware to generate low-frequency heating noise when the cooker is heating a pot at low power.

[0003] While traditional single-tube induction cookers can reduce power consumption by shortening the output pulse width, this shortened pulse results in excessively short conduction times for the power switching components, leading to hard switching. Hard switching causes a sudden increase in power consumption in the power switching components, generating significant heat and impacting the performance and lifespan of the cooker. Furthermore, the current spikes generated by hard switching amplify the existing electromagnetic interference (EMI) issues of traditional single-tube induction cookers, causing some to fail EMI safety tests. Summary of the Invention

[0004] In view of this, this case discloses a low-power continuous heating method, comprising detecting a heating power; determining whether the heating power is less than a power level, and if so, performing the following steps: controlling an input voltage of a power switching module to rise to a first reference voltage according to a first voltage change rate during a first boost period, wherein the first reference voltage is greater than or equal to a turn-on voltage of the power switching module; controlling the input voltage of the power switching module to rise to a second reference voltage according to a second voltage change rate during a second boost period; and controlling the input voltage of the power switching module to rise to a maximum voltage according to a third voltage change rate during a third boost period and maintaining it for a first constant voltage period.

[0005] In some embodiments, the mathematical relationship between the input voltage of the power switching module in the above-described low-power continuous heating method and time during the first boost period, the second boost period, and the third boost period is a strictly increasing function, wherein the average value of the first voltage change rate during the first boost period is greater than the average value of the third voltage change rate during the third boost period, and the average value of the third voltage change rate during the third boost period is greater than the average value of the second voltage change rate during the second boost period.

[0006] In some embodiments, the second boost period of the above-described low-power continuous heating method is greater than the first boost period and the third boost period.

[0007] In some embodiments, the low-power continuous heating method further includes detecting the output voltage of one of the power switching modules and calculating the number of times the power switching module is in a hard-switching state; and calculating the number of times the power switching module is in the hard-switching state.

[0008] This case also discloses a heating device comprising a resonant module, a power switch module, a voltage change rate control module, a power supply module, a microcontroller module, a voltage detection module, and a voltage sensing module. The resonant module is used to generate energy through electromagnetic induction. The power switch module has an input terminal, an output terminal, and a ground terminal. The output terminal is electrically connected to the resonant module to drive it to generate energy through electromagnetic induction. The voltage change rate control module is electrically connected to the input terminal of the power switch module to adjust the input voltage according to a voltage change rate. The power supply module is electrically connected to the voltage change rate control module to provide power to it. The microcontroller module is electrically connected to the voltage change rate control module to output a control signal to control the module to adjust the voltage change rate. The voltage detection module is electrically connected to both the input terminal of the power switch module and the microcontroller module to detect the input voltage of the power switch module to trigger the microcontroller module to adjust the control signal.

[0009] In some embodiments, the power switching module of the heating device is selected from the group consisting of an insulated gate bipolar transistor (IGBT), a power bipolar junction transistor (Power BJT), a metal-oxide-semiconductor field-effect transistor (MOSFET), and combinations thereof.

[0010] In some embodiments, the microcontroller module of the heating device is further configured to control the voltage change rate control module to adjust the input voltage of the power switch module according to a first voltage change rate, so that the input voltage of the power switch module rises to a first reference voltage according to the first voltage change rate during a first boost period, wherein the first reference voltage is greater than or equal to the on-state voltage of the power switch module; the microcontroller module is further configured to control the voltage change rate control module to adjust the input voltage of the power switch module according to a second voltage change rate, so that the input voltage of the power switch module rises from the first reference voltage to a second reference voltage according to the second voltage change rate during a second boost period; and the microcontroller module is further configured to control the voltage change rate control module to adjust the input voltage of the power switch module according to a third voltage change rate, so that the input voltage of the power switch module rises from the second reference voltage to a maximum voltage according to the third voltage change rate during a third boost period.

[0011] In some embodiments, the mathematical relationship between the input voltage of the power switching module of the heating device and time during the first boost period, the second boost period, and the third boost period is a strictly increasing function, wherein the average value of the first voltage change rate during the first boost period is greater than the average value of the third voltage change rate during the third boost period, and the average value of the third voltage change rate during the third boost period is greater than the average value of the second voltage change rate during the second boost period.

[0012] In some embodiments, the second pressurization period of the heating device is greater than the first pressurization period and the third pressurization period.

[0013] In some embodiments, the heating device further includes a power switch voltage detection and counting module, which is used to detect the output voltage of the power switch module and count the number of times the power switch module is in a hard-switching state. Attached Figure Description

[0014] Figure 1 This is a functional block diagram of a heating device according to an embodiment of the present invention.

[0015] Figure 2 This is a circuit characteristic diagram of the power switch module of a heating device according to an embodiment of the present invention.

[0016] Figure 3 This is a voltage waveform diagram of the input terminal of the power switch module of a heating device according to an embodiment of the present invention.

[0017] Figure 4This is a flowchart (a) of a control method for a heating device according to an embodiment of the present invention.

[0018] Figure 5 This is a flowchart (II) of a control method for a heating device according to an embodiment of the present invention.

[0019] Figure 6 This is a waveform diagram (a) showing the hard switching phenomenon generated by the power switching module of a heating device according to an embodiment of the present invention.

[0020] Figure 7 This is a waveform diagram (II) of a heating device according to an embodiment of the present invention, showing the hard switching phenomenon generated by the power switching module.

[0021] The reference numerals in the attached figures are explained as follows:

[0022] 100: Heating device

[0023] 110: Resonant Module

[0024] 120: Power Switch Module

[0025] 130: Voltage Change Rate Control Module

[0026] 140: Power Module

[0027] 150: Microcontroller Module

[0028] 160: Voltage detection module

[0029] 170: Power switch voltage detection and counting module

[0030] I C Output current of the power switching module

[0031] IN: (Input terminal of the power switch module)

[0032] OUT: (Output terminal of the power switch module)

[0033] R1: Dashed box

[0034] S10-S70: Steps

[0035] S701-S702: Steps

[0036] Slew-Rate1: First voltage change rate

[0037] Slew-Rate2: Second voltage change rate

[0038] Slew-Rate3: Third voltage change rate

[0039] t1: First boost period

[0040] t2: Second boost period

[0041] t3: Third boost period

[0042] t4: During the first constant voltage period

[0043] Vcc: Maximum voltage

[0044] V CE The voltage difference between the output terminal and the ground terminal of the power switching module

[0045] V G Input voltage of the power switch module

[0046] V GE The voltage difference between the input terminal and the ground terminal of the power switch module.

[0047] Vref1: First reference voltage

[0048] Vref2: Second reference voltage

[0049] Vss: Minimum voltage

[0050] Vth: Turn-on voltage (critical voltage) Detailed Implementation

[0051] The following will disclose some embodiments of the present invention with reference to the drawings. For clarity, many practical details will be described in the following description, but this is not intended to limit the claims of the present invention.

[0052] Please refer to Figure 1 , Figure 1 This is a modular functional block diagram of a heating device 100 according to an embodiment of the present invention. Figure 1As shown, the heating device 100 includes a resonant module 110, a power switch module 120, a power switch voltage detection and counting module 170, a voltage change rate control module 130, a power supply module 140, a microcontroller module 150, and a voltage detection module 160. The power switch module 120 has an input terminal IN, an output terminal OUT, and a ground terminal (shared with the heating device 100). The output terminal OUT of the power switch module 120 is electrically connected to the resonant module 110. The voltage change rate control module 130 is electrically connected to the input terminal IN of the power switch module 120. The power supply module 140 is electrically connected to the voltage change rate control module 130. The microcontroller module 150 is electrically connected to the voltage change rate control module 130. The voltage detection module 160 is electrically connected to the input terminal IN of the power switch module 120, the voltage change rate control module 130, and the microcontroller module 150. The power switch voltage detection and counting module 170 is electrically connected to the output terminal OUT of the power switch module 120 and the microcontroller module 150.

[0053] The resonant module 110 is used to generate energy through electromagnetic induction. In some embodiments, the resonant module 110 consists of a coil and a capacitor. When a current intermittently flows into the resonant module 110, the current oscillates between the coil and the capacitor, wherein the intermittent flow of the current into the resonant module 110 means that the current value flowing into the resonant module 110 changes over time. At this time, the resonant module 110 generates an electromagnetic induction phenomenon and produces an eddy current in an external medium. The eddy current generates energy and heats the external medium. In some embodiments, the external medium is a ferromagnetic cookware, such as a stainless steel pot or a cast iron pot.

[0054] The power switch module 120 causes the resonant module 110 to undergo electromagnetic induction to generate energy. When the power switch module 120 is turned on, a current is generated at its output terminal OUT; when the power switch module 120 is turned off, the current flows out at its ground terminal. Therefore, when the power switch module 120 is intermittently in a turned-on and turned-off state, the current intermittently flows into the resonant module 110, causing it to undergo electromagnetic induction to generate energy. In some embodiments, the power switch module 120 is selected from the group consisting of an insulated-gate bipolar transistor (IGBT), a power bipolar junction transistor (Power BJT), a power metal-oxide-semiconductor field-effect transistor (Power MOSFET), and combinations thereof.

[0055] Please refer to Figure 2 , Figure 2This is a circuit characteristic diagram of the power switching module 120 of the heating device 100 according to an embodiment of the present invention. In this embodiment, the power switching module 120 is an insulated-gate bipolar transistor (IGBT), wherein the input terminal IN of the power switching module 120 is the gate terminal of the IGBT, the output terminal OUT of the power switching module 120 is the drain terminal of the IGBT, and the ground terminal of the power switching module 120 is the source terminal of the IGBT. Figure 2 As shown, Figure 2 The vertical axis represents the current flowing through the output terminal OUT of the power switch module 120, in amperes (A). Figure 2 The horizontal axis represents the voltage difference V between the output terminal OUT of the power switch module 120 and the ground terminal. CE The unit is volts (V). In some embodiments, the ground terminal voltage of the power switch module 120 is 0 volts, therefore the voltage difference V between the output terminal OUT of the power switch module 120 and the ground terminal is... CE This can be considered as the output voltage OUT; similarly, the voltage difference V between the input terminal IN and the ground terminal of the power switch module 120 can be considered as the output voltage OUT. GE This can also be considered as the input terminal IN voltage. When the input terminal IN voltage of the power switch module 120 is greater than or equal to the turn-on voltage (Vth) of the power switch module 120, the power switch module 120 will be in the on state, and at this time, a current will be generated at the output terminal OUT of the power switch module 120. As shown in R1, assuming that the output terminal OUT voltage of the power switch module 120 is fixed at 3 volts, the larger the input terminal IN voltage of the power switch module 120, the larger the value of the current will be.

[0056] The voltage change rate control module 130 is used to adjust the input voltage of the power switch module 120 according to a voltage change rate. In some embodiments, the voltage change rate control module 130 receives power from the power supply module 140 and outputs a voltage signal to the power switch module 120 according to the voltage change rate. That is, the voltage signal is not at a fixed voltage value, but changes over time according to the voltage change rate. When the voltage value received at the input terminal IN of the power switch module 120 is greater than or equal to the turn-on voltage of the power switch module 120, the power switch module 120 is in the on state. In some embodiments, the voltage change rate control module 130 can be a separate chip or integrated with the microcontroller module 150 into a system-on-a-chip (SoC).

[0057] The power module 140 provides electrical energy to the voltage change rate control module 130, enabling the voltage change rate control module 130 to output voltage to the input terminal IN of the power switch module 120 to control the conduction state of the power switch module 120. In some embodiments, the power module 140 may be a power supply, a power converter, or a power inverter connected to an external power source.

[0058] The microcontroller module 150 outputs a control signal to control the voltage change rate control module 130 to adjust the voltage change rate. In some embodiments, the microcontroller module 150 adjusts the value of the voltage change rate by outputting a control signal, thereby controlling the voltage change rate control module 130 to output an adjusted voltage to the input terminal IN of the power switch module 120 according to the adjusted voltage change rate. That is, the heating device 100 can control the input voltage of the power switch module 120 through the microcontroller module 150, thereby controlling the conduction state of the power switch module 120. In some embodiments, the microcontroller module 150 is disposed in the microcontroller chip of the heating device 100. In some embodiments, the microcontroller module 150 has a counter or a timer, wherein the counter is used to count the number of times the voltage change rate is adjusted, and the timer is used to time the adjustment time required for the voltage change rate. In some embodiments, the microcontroller module 150 receives the adjustment signal output by the power switch voltage detection and counting module 170 to adjust the control signal to adjust the value of the voltage change rate, and then controls the voltage change rate control module 130 to output an adjusted voltage signal to the input terminal IN of the power switch module 120 according to an adjusted voltage change rate.

[0059] The voltage detection module 160 is used to detect the input voltage of the power switch module 120 and trigger the microcontroller module 150 to adjust the control signal based on the input voltage of the power switch module 120. In some embodiments, when the input voltage of the power switch module 120 rises to a specific voltage value, the voltage detection module 160 detects this and triggers the microcontroller module 150 to adjust the control signal based on the voltage value. When the microcontroller module 150 outputs an adjusted control signal to the voltage change rate control module 130, the voltage change rate control module 130 adjusts the voltage change rate accordingly based on the adjusted control signal, and then outputs an adjusted voltage to the input terminal IN of the power switch module 120 based on the adjusted voltage change rate. In some embodiments, the voltage detection module 160 can be a chip (IC chip) independent of the microcontroller module 150, or it can be integrated with the microcontroller module 150 to form a system-on-a-chip suitable for IH heating devices.

[0060] The power switch voltage detection and counting module 170 is used to detect the output voltage of the power switch module 120 and determine whether the power switch module 120 is in a hard-switching state when it is turned on. If the power switch module 120 is in a hard-switching state, the counter of the power switch voltage detection and counting module 170 will increment by 1; if the power switch module 120 is not in a hard-switching state, the counter of the power switch voltage detection and counting module 170 will not move. When the count value of the power switch voltage detection and counting module 170 reaches a threshold, the power switch voltage detection and counting module 170 will output an adjustment signal to the microcontroller module 150, wherein the value of the set value can be defined by the user. Since the power switch module 120 is not damaged after a fixed number of turns, but rather due to long-term accumulation, the user can define the value of the set value according to the usage status of the power switch module 120, thereby improving the accuracy of the microcontroller module 150 in controlling the input voltage IN of the power switch module 120.

[0061] Please refer to the following at the same time Figure 3 , Figure 4 as well as Figure 5 , Figure 3 This is a voltage waveform diagram of the input terminal IN of the power switch module 120 of the heating device 100 according to an embodiment of the present invention. Figure 4 and Figure 5 This is a flowchart of a control method for a heating device 100 according to an embodiment of the present invention. Figure 3 and Figure 4As shown, when the heating device 100 starts operating, the heating device 100 detects a heating power set by the user through the microcontroller module 150 (step S10) and determines whether the heating power is less than a power level (step S20). The value of the power level can be defined by the user according to their needs. In some embodiments, the power level is 1000 watts (W). If the heating power is less than the power level, it means that the heating device 100 will perform low-power continuous heating. At this time, the heating device 100 controls the voltage change rate control module 130 to output voltage to the input terminal IN of the power switch module 120 through the microcontroller module 150, so that the input terminal voltage of the power switch module 120 rises to the first reference voltage Vref1 according to the first voltage change rate Slew-Rate1 during the first boost period t1, wherein the first reference voltage Vref1 is greater than or equal to the on-state voltage Vth of the power switch module 120 (step S30). At this time, the output terminal OUT of the power switch module 120 will generate an on-state current.

[0062] The purpose of step S30 is to enable the power switch module 120 to quickly enter the conduction state to avoid affecting the time for providing effective heating power. Therefore, the microcontroller module 150 sets the first voltage change rate Slew-Rate1 to a large value, so that the input voltage of the power switch module 120 rises to the first reference voltage Vref1 at a faster rate, thereby shortening the time taken for the power switch module 120 to enter the conduction state. The first voltage change rate Slew-Rate1 is a strictly increasing function of voltage and time. In some embodiments, the first voltage change rate Slew-Rate1 is a value selected from the range of 0.009V / ns to 0.18V / ns, wherein the voltage change rate range ensures that the conduction current does not increase abruptly. The first reference voltage Vref1 is a value selected from the range of 7 volts to 9 volts, wherein the voltage range is related to the electrical characteristics of the power switch module 120, and the first boost period t1 is adjusted accordingly based on the first voltage change rate Slew-Rate1 and the first reference voltage Vref1.

[0063] Next, the heating device 100 controls the voltage change rate control module 130 via the microcontroller module 150 to adjust the input voltage of the power switch module 120 to rise to the second reference voltage Vref2 according to the second voltage change rate Slew-Rate2 during the second boost period t2 (step S40). The purpose of step S40 is to avoid the problem of hard switching caused by a rapid change in the value of the conduction current. Therefore, the microcontroller module 150 will adjust the voltage according to the circuit characteristics of the power switch module 120 (e.g., ...). Figure 2As shown, the second voltage change rate Slew-Rate2 is set to a small value, causing the input voltage of the power switch module 120 to rise to the second reference voltage Vref2 at a slower rate. The mathematical relationship between the voltage and time of the second voltage change rate Slew-Rate2 is a strictly increasing function. Because the IGBT conduction time is short during low-power heating, insufficient LC resonant energy can cause the IGBT to hard-turn on the next cycle. Simultaneously, a higher gate voltage results in a larger instantaneous drain current, causing the IGBT to overheat. Prolonged operation in this state can easily damage the IGBT. In some embodiments, the second voltage change rate Slew-Rate2 is selected from a value between 0.01V / ns and 1V / ns, the second reference voltage Vref2 is selected from a value between 10 volts and 12 volts, and the second boost period t2 is adjusted accordingly based on the second voltage change rate Slew-Rate2 and the second reference voltage Vref2, wherein the second boost period t2 is greater than the first boost period t1.

[0064] Subsequently, the heating device 100, through the microcontroller module 150, controls the voltage change rate control module 130 to adjust the input voltage of the power switch module 120 to rise to the maximum voltage Vcc according to the third voltage change rate Slew-Rate3 during the third boost period t3 and maintain it for the first constant voltage period t4 (step S50). The mathematical relationship between the third voltage change rate Slew-Rate3 and time is a strictly increasing function. The purpose of step S50 is to rapidly boost the input voltage of the power switch module 120, causing the conduction current to rise to a larger value, thereby providing the resonant module 110 with sufficient power for electromagnetic induction. Therefore, the microcontroller module 150 sets the third voltage change rate Slew-Rate3 to a larger value, causing the input voltage of the power switch module 120 to rise to the maximum voltage Vcc at a faster rate and maintain it for the first constant voltage period t4. In this way, the resonant module 110 can receive sufficient power for electromagnetic induction. In some embodiments, the third voltage change rate Slew-Rate3 is a value selected from the range of 0.009V / ns to 0.18V / ns, and the maximum voltage Vcc is a value selected from the range of 16 volts to 20 volts, wherein the voltage range is related to the electrical characteristics of the power switching module 120, and the third boost period t3 is adjusted accordingly based on the third voltage change rate Slew-Rate3 and the maximum voltage Vcc, wherein the third boost period t3 is less than or equal to the second boost period t2. In some embodiments, the magnitude relationships between the minimum voltage Vss, the turn-on voltage Vth, the first reference voltage Vref1, the second reference voltage Vref2, and the maximum voltage Vcc are as follows:

[0065] Vss<Vth≤Vref1<Vref2<V CC .

[0066] After the first constant voltage period t4 ends, the heating device 100 controls the voltage change rate control module 130 via the microcontroller module 150 to stop outputting voltage to the input terminal IN of the power switch module 120, causing the input voltage of the power switch module 120 to drop to the minimum voltage Vss. At this time, the power switch module 120 will be in a non-conducting state (step S60). The value of the first constant voltage period t4 is related to the operating power of the heating device 100; the greater the operating power, the longer the first constant voltage period t4. Finally, when the heating device 100 is restarted or the heating power is readjusted, by repeating steps S10 to S60, the conducting current will intermittently flow into the resonant module 110 of the heating device 100, causing the resonant module 110 to perform electromagnetic induction to generate energy. In this way, the heating device 100 can achieve the function of low-power continuous heating.

[0067] like Figure 5 As shown, if the heating power is not less than the power level (i.e., the heating power is greater than or equal to the power level), it means that the heating device 100 is to perform high-power continuous heating (step S70). At this time, the heating device 100 will adjust the input IN signal of the voltage change rate control module 130 to the power switch module 120 through the microcontroller module 150, so that the input voltage V of the power switch module is... G During the period when the voltage rises to the maximum voltage Vcc and is maintained at a second constant voltage (step S701), the power switch module 120 will be in the on state and generate a conduction current at the output terminal OUT of the power switch module 120.

[0068] When the second constant voltage period ends, the heating device 100 controls the voltage change rate control module 130 to stop outputting voltage to the input terminal IN of the power switch module 120, so that the input terminal voltage V of the power switch module... G When the voltage drops to the minimum value Vss, the power switch module 120 will be in a non-conducting state (step S702). Finally, by repeating steps S701 and S702, the conducting current will intermittently flow into the resonant module 110 of the heating device 100, causing the resonant module 110 to generate energy through electromagnetic induction. In this way, the heating device 100 can achieve the function of high-power continuous heating.

[0069] In some embodiments, the user can customize the values ​​of the first voltage change rate Slew-Rate1, the second voltage change rate Slew-Rate2, and the third voltage change rate Slew-Rate3 at different times through the microcontroller module 150, so that the input voltage V of the power switch module is...G The voltage can be increased to the maximum voltage Vcc at different times based on different slope values; or all boost periods (first boost period t1, second boost period t2, and third boost period t3) can be adjusted. The number of reference voltage values ​​can also be set, but at least two are required. In some embodiments, the average value of the first voltage change rate Slew-Rate1 in the first boost period t1 is greater than the average value of the third voltage change rate Slew-Rate3 in the third boost period t3, and the average value of the third voltage change rate Slew-Rate3 in the third boost period t3 is greater than the average value of the second voltage change rate Slew-Rate2 in the second boost period t2. It should be specifically noted that the average value of the first voltage change rate Slew-Rate1 is equal to the input voltage V of the power switching module. G The derivative of the voltage change over time is integrated over the first boost period t1 and divided by the first boost period t1. Similarly, the average value of the second voltage change rate Slew-Rate2 is equal to the input voltage V of the power switch module. G The derivative with respect to time is the integral of the second boost period t2 divided by the second boost period t2; the average value of the third voltage change rate Slew-Rate3 is equal to the input voltage V of the power switch module. G The integral of the derivative with respect to time over the third boost period t3, divided by the third boost period t3, is given by the following formula:

[0070]

[0071] Please refer to the following at the same time Figure 6 as well as Figure 7 , Figure 6 and Figure 7 This is a waveform diagram illustrating the hard-switching phenomenon generated by the power switching module 120 of the heating device 100 according to an embodiment of the present invention. Figure 6 As shown, when the heating device 100 uses a conventional single-drive voltage heating method for low-power continuous heating, the input voltage V of the power switch module... G The voltage is instantly boosted to the maximum voltage Vcc, causing the conduction time of the power switch module 120 to be too short. Therefore, the output current I of the power switch module is... C The waveform fluctuates significantly, causing the power switch module 120 to experience hard switching. When the heating device 100 uses the heating method of an embodiment of the present invention to perform low-power continuous heating, such as… Figure 7 As shown, due to the input voltage V of the power switch module GThe voltage will first be pulled up to the first reference voltage Vref1 and the second reference voltage Vref2, and finally pulled up to the maximum voltage Vcc. Therefore, the conduction time of the power switch module 120 will be extended, resulting in a higher output current I. C The waveform will be more stable, thus mitigating the negative impact of hard switching issues.

[0072] Please refer to Table 1, which is a temperature comparison table of the power switch module 120 of the heating device 100 according to an embodiment of the present invention. As shown in Table 1, when the heating device 100 uses a conventional single-drive voltage heating method for low-power continuous heating, the temperature of the power switch module 120 rises to 46°C; when the heating device 100 uses the heating method of an embodiment of the present invention for low-power continuous heating, the temperature of the power switch module 120 only rises to 44°C, thereby improving the power conversion efficiency of the heating device 100 during operation.

[0073] [Table 1]

[0074] Single drive voltage 22 46 The heating method of the present invention 22 44

[0075] Please refer to Table 2, which is a noise comparison table between the heating device 100 according to an embodiment of the present invention and a conventional induction cooker. As shown in Table 2, in an environment with a noise level of 44 dB, when a conventional induction cooker performs low-power continuous heating, it will produce 60 dB of noise; in contrast, when the heating device 100 performs low-power continuous heating using the heating method of an embodiment of the present invention, it will only produce 51 dB of noise, which is significantly lower.

[0076] [Table 2]

[0077] Noise level (dB) 51 60

[0078] Please refer to Table 3, which is a comparison table of electromagnetic interference (EMI) of the heating device 100 according to an embodiment of the present invention. As shown in Table 3, at frequencies of 0.15MHz and 3.93MHz, when the heating device 100 uses a conventional single-drive voltage heating method for low-power continuous heating, the heating device 100 generates radiation values ​​of 56.12 (dBμV) and 40.77 (dBμV), respectively. In contrast, when the heating device 100 uses the heating method of an embodiment of the present invention for low-power continuous heating, the heating device 100 only generates radiation values ​​of 51.39 (dBμV) and 35.67 (dBμV), respectively, significantly reducing electromagnetic interference to other circuit components.

[0079] [Table 3]

[0080]

[0081] In summary, according to the control method of the heating device 100 disclosed in this case, the heating device 100 can control multiple voltage change rate values ​​through the microcontroller module 150 to adjust the input voltage of the power switch module 120, thereby extending the conduction time of the power switch module 120. In this way, while achieving low-power continuous heating, the heating device 100 can not only avoid the hard-switching problem caused by the power switch module 120, but also reduce the operating temperature of the power switch module 120, and further reduce the impact of electromagnetic interference (EMI) on the heating device 100. Furthermore, since the control method of the heating device 100 reduces the electromagnetic force generated by the resonant module 110 of the heating device 100 during electromagnetic induction, the low-frequency noise generated by the pot will decrease when the heating device 100 continuously heats a pot at low power. Combined with long-term monitoring by the power switch voltage detection and counting module 170, this helps prevent premature damage to the power switch module 120.

[0082] Although the present invention has been disclosed above with reference to embodiments, it is not intended to limit the creation of the present invention. Anyone skilled in the art can make some modifications and variations without departing from the spirit and scope of the present disclosure, and such modifications and variations are still within the scope of the claims of the present invention.

Claims

1. A low-power continuous heating method, characterized in that, Include: Detect heating power; and Determine if the heating power is less than a certain power level. If so, proceed with the following steps: An input voltage of a power switching module is controlled to rise to a first reference voltage according to a first voltage change rate during a first boost period, wherein the first reference voltage is greater than or equal to a turn-on voltage of the power switching module. The input voltage of the power switch module, which is in the on state, is controlled to rise from the first reference voltage to a second reference voltage according to a second voltage change rate during a second boost period. as well as The input voltage of the power switch module, which is in the ON state, rises from the second reference voltage to a maximum voltage according to a third voltage change rate during a third boost period and is maintained at a first constant voltage period. The input voltage of the power switch module exhibits a strictly increasing relationship with time during the first, second, and third boost phases. Specifically, the average rate of change of the first voltage during the first boost phase is greater than the average rate of change of the third voltage during the third boost phase, and the average rate of change of the third voltage during the third boost phase is greater than the average rate of change of the second voltage during the second boost phase. The second boost period is longer than the first boost period and the third boost period.

2. The low-power continuous heating method as described in claim 1, characterized in that, Also includes: Detect the output voltage of the power switch module and calculate the number of times the power switch module is in a hard-switching state; and Count the number of times the power switch module is in this hard-switching state.

3. A heating device, characterized in that, Include: A resonant module is used to perform an electromagnetic induction to generate energy; A power switching module has an input terminal, an output terminal and a ground terminal. The output terminal is electrically connected to the resonant module to drive the resonant module to perform electromagnetic induction to generate the energy. A voltage change rate control module is electrically connected to the input terminal of the power switch module to adjust the input voltage of the power switch module according to a voltage change rate. A power supply module is electrically connected to the voltage change rate control module to provide a power supply to the voltage change rate control module. A microcontroller module, electrically connected to the voltage change rate control module, is used to output a control signal to control the voltage change rate control module to adjust the voltage change rate; and A voltage detection module is electrically connected to the input terminal of the power switch module and the microcontroller module to detect the voltage at the input terminal of the power switch module and trigger the microcontroller module to adjust the control signal. The microcontroller module is further configured to control the voltage change rate control module to adjust the input voltage of the power switch module according to a first voltage change rate, a second voltage change rate, and a third voltage change rate, respectively. This causes the input voltage of the power switch module to rise to a first reference voltage according to the first voltage change rate during a first boost period, wherein the first reference voltage is greater than or equal to a turn-on voltage of the power switch module. During a second boost period, the microcontroller module controls the input voltage of the power switch module in the turn-on state to rise from the first reference voltage to a second reference voltage according to the second voltage change rate. Furthermore, during a third boost period, the microcontroller module controls the input voltage of the power switch module in the turn-on state to rise from the second reference voltage to a maximum voltage according to the third voltage change rate and maintain this maximum voltage for a first constant voltage period. The input voltage of the power switch module exhibits a strictly increasing relationship with time during the first, second, and third boost periods. Furthermore, the average value of the first voltage change rate during the first boost period is greater than the average value of the third voltage change rate during the third boost period, and the average value of the third voltage change rate during the third boost period is greater than the average value of the second voltage change rate during the second boost period. The second boost period is longer than the first boost period and the third boost period.

4. The heating device as described in claim 3, characterized in that, The power switching module is selected from a group consisting of an insulated gate bipolar transistor, a power bipolar junction transistor, a power metal-oxide-semiconductor field-effect transistor, and combinations thereof.

5. The heating device as described in claim 3, characterized in that, The heating device also includes a power switch voltage detection and counting module, which is used to detect the output voltage of the power switch module and to count the number of times the power switch module is in a hard-switching state.

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