Noise reduction method for single-tube multi-head induction cooker

Abstract

The noise reduction method for the single-tube multi-head induction cooker comprises the following steps: acquiring target power and oscillation frequency of each furnace end, and acquiring a current signal through current detection; according to the obtained current signal, adjusting a programmable pulse generator (PPG) mode so as to control the operation of the main furnace end and the slave furnace end, so that the oscillation frequency of the main furnace end and the oscillation frequency of the slave furnace end are kept synchronous; and the oscillation frequency of current operation of the main furnace end is obtained, and the PPG signal of the main furnace end is adjusted according to the target power and the frequency range of the main furnace end until the oscillation frequency and the power of the main furnace end reach the target range. The method has the beneficial effects that by adjusting the on-off of the commercial power period, the power of the slave furnace end in current operation and the target power are maintained in the set range, so that the working noise is reduced, and the user experience is improved; the problem that in the prior art, obvious noise is generated when at least two groups of resonance circuits of a multi-burner single-tube and half-bridge structure induction cooker work at the same time is solved, and noise generated by mutual coupling between burner coils is prevented.

Description

Technical Field

[0001] The invention relates to the technical field of induction cookers, in particular to a noise reduction method for a single-tube multi-head induction cooker. Background Art

[0002] In modern household and commercial kitchens, induction cookers are increasingly favored by consumers due to their high efficiency, energy saving, and easy operation. With the diversification of consumers' cooking needs, multi-burner induction cookers, as a kitchen appliance that can support independent control of multiple burners at the same time, have gradually become the mainstream product in the market. Compared with traditional single-burner induction cookers, multi-burner induction cookers show significant advantages during use, especially in terms of saving space and improving cooking efficiency. At the same time, single-tube induction cookers have been widely used in the design of multi-burner induction cookers due to their simple structure and low cost, further reducing the production cost of the product and making it more competitive in the market.

[0003] However, in actual use, multi-burner induction cookers often produce obvious abnormal noise, especially when multiple burners are working at the same time. This noise not only affects the user experience, but may also have an adverse effect on the kitchen environment. The main reason for the noise is that although the oscillation frequency of the main resonant circuit of the induction cooker operates outside the audio range above 20kHz, when multiple burners are working at the same time, the coils between the burners will be coupled with each other, resulting in a beat phenomenon, thereby generating annoying noise. This noise problem is particularly prominent in the application of multi-burner induction cookers, so it is necessary to make further improvements to it. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a noise reduction method for a single-tube multi-head induction cooker which has a simple structure, is easy to use and can effectively prevent noise generated by mutual coupling between burner coils.

[0005] The object of the invention is achieved in the following manner: A noise reduction method for a single-tube multi-burner induction cooker comprises the following steps: S1: Obtain the target power and oscillation frequency of each burner; S2: Based on the target oscillation frequency of each burner, determine the main burner and the slave burner, wherein the burner with the lowest target oscillation frequency is used as the main burner, and its corresponding resonant circuit is the main resonant circuit, and the remaining burners are used as slave burners, and their corresponding resonant circuits are slave resonant circuits; S3: Acquire current signal through current detection; S4: According to the acquired current signal, a programmable pulse generator (PPG) mode is adjusted to control the operation of the master burner and the slave burner, so that the oscillation frequency of the master burner is synchronized with the oscillation frequency of the slave burner; S5: obtaining the current oscillation frequency of the main burner, and adjusting the PPG signal of the main burner according to the target power and frequency range of the main burner until the oscillation frequency and power thereof reach the target range; S6: setting the oscillation frequency of the master burner to the operating oscillation frequency of the slave burner, and adjusting the PPG signal of the slave burner based on the frequency deviation so that the frequency deviation is maintained within a set range; S7: Adjust the on / off state of the mains cycle to maintain the power from the burner within the set target power range.

[0006] Further: after adjusting the PPG signal of the main furnace, it also includes: Detecting the highest voltage parameter of the high-frequency switch device and determining whether the voltage parameter is greater than a preset voltage threshold; If the voltage parameter is greater than the set voltage threshold, the peak voltage of the main furnace head PPG signal is reduced by frequency jittering technology, or the maximum voltage peak is limited according to the maximum voltage parameter of the switching tube to adjust the oscillation frequency of the main furnace head resonant circuit.

[0007] Further: after adjusting the PPG signal from the furnace head, the method further includes: Detecting the highest voltage parameter of the high-frequency switch device and determining whether the voltage parameter is greater than a preset voltage threshold; If the voltage parameter is greater than the set voltage threshold, the peak voltage of the slave burner PPG signal is reduced by frequency jittering technology, or the maximum voltage peak is limited according to the maximum voltage parameter of the switch tube to adjust the oscillation frequency of the slave burner resonant circuit.

[0008] Furthermore: the adjustment process of the main furnace head PPG signal specifically includes: When the main burner frequency is not within the set main burner target frequency range, adjust the pulse width of the main burner PPG signal until the main burner frequency reaches the target frequency range; Determine whether the main furnace head PPG signal has reached the target frequency, and whether the main furnace head power is still less than the target power of the main furnace head; If the above conditions are met, it is considered that the pot placement position at the main burner is offset, and the working state of the slave burner is further detected; The frequency of the slave burner is set within the target power frequency range of the slave burner, and the slave burner is operated in the on-off state of the mains cycle; When the oscillation frequency of the slave burner is not equal to the oscillation frequency of the master burner and the frequency deviation exceeds the set range, the pulse width of the slave burner PPG signal is adjusted until the frequency deviation is maintained within the set range.

[0009] Further: the adjusting the mains power cycle on and off to maintain the secondary burner power within a set target power range specifically includes: When the oscillation frequency of the slave burner is not within the oscillation frequency range of the master burner and the frequency deviation exceeds the maximum value of the set frequency range, adjusting the oscillation frequency of the slave burner until it is within the oscillation frequency range of the master burner; If the above conditions are met, the slave burner is operated in the on-off state of the AC power cycle, the zero crossing point of the input AC power cycle is obtained to determine the power wave cycle, and the power is adjusted by changing the on-off state of the AC power cycle to maintain the slave burner power within the set target power range.

[0010] Further: after adjusting the PPG signal from the furnace head, it also includes: Adjust the on / off state of the mains cycle. When the secondary furnace head works in the on / off state of the mains cycle, the mains cycle and the zero-crossing point are detected by the mains power supply cycle detection circuit; Before the start time of the cycle, the zero point of the mains cycle is determined first, so that the slave burner is driven at a specific frequency before the zero point to reduce the noise during startup; Among them, the drive signal from the furnace head is a 9V drive signal, and the drive signal is an 18V drive signal after the mains power cycle passes through zero.

[0011] Furthermore: the adjustment process of the slave burner PPG signal specifically includes: When the oscillation frequency of the slave burner is within the oscillation frequency range of the master burner, determining whether the power of the master burner is within the target power range of the slave burner; If the power of the main burner is not within the target power range of the slave burner, the power of the slave burner is maintained within the set target power range by increasing or decreasing the on / off cycle of the commercial power supply.

[0012] Further: the process of determining the main burner and the slave burner specifically includes: Selecting the lowest target oscillation frequency from the target oscillation frequencies of the burners, taking the burner corresponding to the lowest target oscillation frequency as the main burner, and taking the lowest target oscillation frequency as the target frequency of the main burner; The remaining burners are regarded as slave burners, and the target frequency of the master burner is regarded as the target frequency of its corresponding slave burner.

[0013] The beneficial effects of the present invention are: 1. Simple structure, low production cost and improved market competitiveness.

[0014] 2. By adjusting the mains power cycle on and off, the currently running slave burner power and the target power are maintained within the set range, thereby reducing the working noise and improving the user experience. The problem of obvious noise generated when at least two groups of resonant circuits of multi-burner single-tube and half-bridge structure induction cookers in the prior art work at the same time can be solved, and the noise generated by mutual coupling between burner coils can be prevented. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is the control principle diagram of the present invention.

[0016] Figure 2 This is the main control circuit diagram of the present invention.

[0017] Figure 3 This is a collector voltage waveform diagram of the high frequency switching device of the present invention.

[0018] Figure 4 , 5 This is a collector voltage waveform diagram of the high-frequency switch device when the main furnace head is running in the present invention. DETAILED DESCRIPTION

[0019] The present invention is further described in detail below with reference to the accompanying drawings. A noise reduction method for a single-tube multi-head induction cooker comprises the following steps: S1: Obtain the target power and oscillation frequency of each burner; S2: Based on the target oscillation frequency of each burner, determine the main burner and the slave burner, wherein the burner with the lowest target oscillation frequency is used as the main burner, and its corresponding resonant circuit is the main resonant circuit, and the remaining burners are used as slave burners, and their corresponding resonant circuits are slave resonant circuits; S3: Acquire current signal through current detection; S4: According to the acquired current signal, a programmable pulse generator (PPG) mode is adjusted to control the operation of the master burner and the slave burner, so that the oscillation frequency of the master burner is synchronized with the oscillation frequency of the slave burner; S5: obtaining the current oscillation frequency of the main burner, and adjusting the PPG signal of the main burner according to the target power and frequency range of the main burner until the oscillation frequency and power thereof reach the target range; S6: setting the oscillation frequency of the master burner to the operating oscillation frequency of the slave burner, and adjusting the PPG signal of the slave burner based on the frequency deviation so that the frequency deviation is maintained within a set range; S7: Adjust the on / off state of the mains cycle to maintain the power from the burner within the set target power range.

[0020] In one embodiment, after adjusting the main furnace head PPG signal, the method further includes: Detecting the highest voltage parameter of the high-frequency switch device and determining whether the voltage parameter is greater than a preset voltage threshold; If the voltage parameter is greater than the set voltage threshold, the peak voltage of the main furnace head PPG signal is reduced by frequency jittering technology, or the maximum voltage peak is limited according to the maximum voltage parameter of the switching tube to adjust the oscillation frequency of the main furnace head resonant circuit.

[0021] In one embodiment, after adjusting the PPG signal from the burner, the method further includes: Detecting the highest voltage parameter of the high-frequency switch device and determining whether the voltage parameter is greater than a preset voltage threshold; If the voltage parameter is greater than the set voltage threshold, the peak voltage of the slave burner PPG signal is reduced by frequency jittering technology, or the maximum voltage peak is limited according to the maximum voltage parameter of the switch tube to adjust the oscillation frequency of the slave burner resonant circuit.

[0022] In one embodiment, the adjustment process of the main furnace head PPG signal specifically includes: When the main burner frequency is not within the set main burner target frequency range, adjust the pulse width of the main burner PPG signal until the main burner frequency reaches the target frequency range; Determine whether the main furnace head PPG signal has reached the target frequency, and whether the main furnace head power is still less than the target power of the main furnace head; If the above conditions are met, it is considered that the pot placement position at the main burner is offset, and the working state of the slave burner is further detected; The frequency of the slave burner is set within the target power frequency range of the slave burner, and the slave burner is operated in the on-off state of the mains cycle; When the oscillation frequency of the slave burner is not equal to the oscillation frequency of the master burner and the frequency deviation exceeds the set range, the pulse width of the slave burner PPG signal is adjusted until the frequency deviation is maintained within the set range.

[0023] In one embodiment, the adjusting the mains power cycle to maintain the secondary burner power within a set target power range specifically includes: When the oscillation frequency of the slave burner is not within the oscillation frequency range of the master burner and the frequency deviation exceeds the maximum value of the set frequency range, adjusting the oscillation frequency of the slave burner until it is within the oscillation frequency range of the master burner; If the above conditions are met, the slave burner is operated in the on-off state of the AC power cycle, the zero crossing point of the input AC power cycle is obtained to determine the power wave cycle, and the power is adjusted by changing the on-off state of the AC power cycle to maintain the slave burner power within the set target power range.

[0024] In one embodiment, after adjusting the PPG signal from the burner, the method further comprises: Adjust the on / off state of the mains cycle. When the secondary furnace head works in the on / off state of the mains cycle, the mains cycle and the zero-crossing point are detected by the mains power supply cycle detection circuit; Before the start time of the cycle, the zero point of the mains cycle is determined first, so that the slave burner is driven at a specific frequency before the zero point to reduce the noise during startup; Among them, the drive signal from the furnace head is a 9V drive signal, and the drive signal is an 18V drive signal after the mains power cycle passes through zero.

[0025] In one embodiment, the adjustment process of the slave burner PPG signal specifically includes: When the oscillation frequency of the slave burner is within the oscillation frequency range of the master burner, determining whether the power of the master burner is within the target power range of the slave burner; If the power of the main burner is not within the target power range of the slave burner, the power of the slave burner is maintained within the set target power range by increasing or decreasing the on / off cycle of the commercial power supply.

[0026] In one embodiment, the process of determining the main burner and the slave burner specifically includes: Selecting the lowest target oscillation frequency from the target oscillation frequencies of the burners, taking the burner corresponding to the lowest target oscillation frequency as the main burner, and taking the lowest target oscillation frequency as the target frequency of the main burner; The remaining burners are regarded as slave burners, and the target frequency of the master burner is regarded as the target frequency of its corresponding slave burner.

[0027] Working principle: The PPG (Programmable Pulse Generator) signal described in this case.

[0028] An induction cooker is a kitchen appliance that uses a single heating element (usually a coil tube) to provide heat for multiple burners.

[0029] Reference Figure 2 In the embodiment of the first aspect of the present invention, the electric control structure of the single-tube multi-burner induction cooker includes at least two groups of resonant circuits, each group of resonant circuits is connected to the same high-frequency switching device IGBT, and the input end of the high-frequency switching device IGBT is connected to a protection drive circuit, frequency and synchronization detection, current detection, and AC power supply cycle detection.

[0030] The protection driving circuit includes: the energy storage capacitor C1 is connected to both ends of the cable drum, the positive pole of the voltage regulator Z1 is connected to the negative pole of the G pole of the IGBT, the resistor R1 is connected in parallel with the voltage regulator Z1, and the diode D2 is connected in parallel with the resistor R1 as the input end.

[0031] The frequency and synchronization detection circuit includes: resistors 3 and 6 divide the voltage of the cable tray connected to the mains rectifier input terminal, capacitor C3 absorbs interference, resistors 4 and 5 divide the voltage of the C pole of the IGBT and the cable tray input terminal, capacitor C5 absorbs interference, and capacitor C6 absorbs cable tray interference.

[0032] The mains power cycle detection circuit and input end are connected to the mains, and the N and L of the mains are connected to D3 and D4 respectively for rectification, and are connected to the chip pins after voltage division by R11, R12 and C8.

[0033] The current detection circuit and input end are connected to the E pole of the IGBT, so that when the IGBT is turned on, the voltage of the current on the constantan wire is output to the chip pin through capacitor C6 and resistor R10 to read the voltage, and the corresponding power is measured after conversion.

[0034] Reference Figure 1 , a noise reduction method for a single-tube multi-head induction cooker, comprising the following steps; S1. Obtain the target power and frequency of each burner, determine the main burner and the slave burner according to the target power and frequency of each burner, and use the resonant circuit corresponding to the main burner as the main burner resonant circuit, and the other resonant circuits corresponding to the slave burners as the slave burner resonant circuits.

[0035] In this embodiment, the master burner and the slave burner are determined according to the power and frequency settings. If the oscillation frequency is the same between the two burners, there is no distinction between the master and slave burners. If the target frequencies of the two burners are in different ranges, the master burner and the slave burner are determined, and the target power and frequency of the master burner are obtained through the frequency and synchronization detection circuit and the current detection circuit.

[0036] The resonant circuit frequency corresponding to the main burner is used as the main frequency, and the resonant frequency of the slave burner is set as the resonant frequency of the main burner. S2, using the PPG mode to control the operation of the main burner and the slave burner, obtain the oscillation frequency of the main burner resonant circuit and the oscillation frequency of the slave burner resonant circuit, and calculate the deviation frequency between the main burner oscillation frequency and the slave burner oscillation frequency.

[0037] In this embodiment, the main burner and the slave burner are regulated by the PPG module, and the PPG signals of each burner start to be output. The PPG signals of the main burner and the slave burner are adjusted according to the set frequency, and the main burner and the slave burner start to operate heating.

[0038] The oscillation frequency of the main burner resonant circuit is obtained in real time and used as the main burner oscillation frequency. The oscillation frequency of the slave burner resonant circuit is obtained in real time and used as a comparison with the main burner oscillation frequency to calculate the deviation frequency between the main burner oscillation frequency and the slave burner oscillation frequency.

[0039] S3, obtaining the power and oscillation frequency PPG signal of the current main burner operation, and adjusting the main burner PG signal according to the deviation between the main burner power and the target power of the main burner until the main burner power and frequency are equal to within the set range of the target power and frequency of the main burner.

[0040] In this embodiment, the actual power and frequency of the main burner currently in operation are obtained and used as the main burner frequency, and the PPG signal of the current operation is obtained and the main burner frequency is used as the slave burner frequency.

[0041] The PPG signal of the main burner is regulated by adjusting the power and frequency of the main burner and the target power and frequency of the main burner, that is, the PPG signal of the main burner is adjusted until the power and frequency of the main burner are within the set range of the target power and frequency of the main burner.

[0042] S4, sets the main burner frequency to the operating frequency of the slave burner, adjusts the slave burner PPG signal according to the deviation frequency, maintains the deviation frequency within the set frequency range, and adjusts the AC power cycle switch to make the slave burner power within the set range of the slave burner target power.

[0043] In this embodiment, the PPG control strategy of the slave burner is to follow the oscillation frequency of the master burner: when the oscillation frequency of the slave burner is greater than that of the master burner, the pulse width of the PPG signal of the slave burner is increased, otherwise, the pulse width of the PPG signal of the slave burner is reduced.

[0044] The actual power currently running from the furnace is obtained and used as the power of the furnace, and the PPG signal currently running is obtained and used as the PPG signal of the furnace.

[0045] The deviation power obtained through step S2 is used to regulate the PPG signal of the slave burner, that is, the PPG signal of the slave burner is adjusted to maintain the deviation frequency within the set frequency range, and the mains power cycle currently running from the slave burner is turned on and off until the slave burner power is within the set range of the target power of the slave burner.

[0046] Among them, the AC power cycle is turned on and off, and the set AC power cycle is a sine wave of the input AC power. The set AC power sine wave cycle on and off adjustment is not specifically limited in the present invention. The set sine wave cycle on and off can be set according to the furnace head control accuracy and heating accuracy. The set AC power sine wave cycle switch can be used to gradually increase or decrease the furnace head power and heating accuracy settings.

[0047] According to the scheme of the above embodiment, the main burner and the slave burner are determined by the set target frequency of each burner, and the PPG mode is used for adjustment to calculate the deviation frequency of the oscillation frequencies of the two burners. The main burner adjusts the pulse width of the main burner PPG signal so that the current running main burner power is within the set range of the target power of the main burner. The slave burner maintains the deviation frequency within the set frequency range by adjusting the pulse width of the slave burner PPG signal, and performs on-off adjustment through the AC power cycle so that the current running slave burner power is within the set range of the target power, and the main burner frequency and the slave burner deviation frequency are maintained within the set frequency range, so as to reduce working noise, enhance user experience, solve the problem in the prior art that at least two groups of resonant circuits of a multi-burner single-tube structure induction cooker will generate obvious noise when working simultaneously, and prevent noise generated by mutual coupling between burner coils.

[0048] In an embodiment of the first aspect of the present invention, in step S1, the process of determining the main burner and the slave burner specifically includes: Step S1.10, selecting the minimum target frequency from the target frequencies set for each burner, taking the burner corresponding to the minimum target frequency as the main burner, and taking the minimum target frequency as the target power of the main burner.

[0049] Step S1.20, taking the remaining burners as slave burners, and the remaining target powers as the corresponding target powers of the slave burners.

[0050] In this embodiment, the target frequencies of several burners are obtained, and the burner with the minimum target frequency is set as the main burner, and the remaining target burners are set as slave burners. The target power corresponds to the burner.

[0051] In an embodiment of the first aspect of the present invention, in step S3, after adjusting the slave burner PPG signal, the method further comprises: Step S5, obtaining a voltage parameter of the high-frequency switch component, and confirming whether the voltage parameter is greater than a set voltage threshold.

[0052] In this embodiment, the high-frequency switching device is detected and the collector voltage on the high-frequency switching device is collected to obtain a voltage parameter, that is, the voltage parameter is the collector voltage of the high-frequency switching device, and it is determined whether the collector voltage is greater than a set voltage threshold.

[0053] Among them, the voltage threshold is set within the range of 1200V-1300V. Step S5.10: If yes, the PPG signal frequency of the main burner is limited so that the high-frequency switch device of the main burner is within the set voltage threshold range, ensuring the frequency of the main burner and making the slave burner dynamically follow the frequency of the main burner.

[0054] In this embodiment, when the collector voltage is greater than the set voltage threshold, the output first PPG signal is limited to obtain the frequency of the main burner. The main burner frequency is first used to make the slave burner dynamically follow the main burner frequency to achieve the slave burner frequency and the main burner frequency are within the range.

[0055] Step S5.20, using the frequency driving signal after limiting the main burner PPG signal, and then driving the high-frequency switching device to operate, so as to adjust the main burner resonant circuit.

[0056] In this embodiment, the frequency is limited to obtain the set drive signal, and the main burner target frequency drive signal is converted into the set frequency drive signal for driving. The high-frequency switching device is driven by the set drive signal to realize the protection operation of the high-frequency switching device, thereby regulating the main burner resonant circuit.

[0057] Step S5.30, since the slave burner works in the on-off state of the mains cycle, the zero point of the mains cycle is first determined before the on-state time of the cycle, so that the slave burner is driven at a specific frequency before starting and crossing zero, so as to reduce the startup noise when the slave burner cycle is in the on state.

[0058] Among them, the drive signal from the furnace head is a 9V drive signal, and the drive signal is an 18V drive signal after the mains power cycle passes through zero.

[0059] In this embodiment, refer to Figure 2 , the main burner driving circuit can be used to execute steps S5 to S5.20, and the slave burner can execute step S5.30.

[0060] Frequency and synchronization detection collects the collector voltage on the high-frequency switching device IGBT to obtain voltage parameters, samples the voltage to the chip through a resistor divider circuit, and determines whether the collector voltage is greater than the set voltage threshold value within the range of 500V-1300V.

[0061] When the collector voltage is greater than the set voltage threshold, the PPG signal frequency of the main burner is limited so that the high-frequency switch device of the main burner is within the set voltage threshold range, ensuring the frequency of the main burner and making the slave burner dynamically follow the main burner frequency.

[0062] The frequency driving signal after limiting the PPG signal of the main burner is used to drive the high-frequency switching device to operate, so as to adjust the main burner resonant circuit.

[0063] In order to ensure that the two burners maintain the same or similar oscillation frequency and maintain their respective output powers, the present invention needs to continuously adjust the intermittent time of the output drive signal. However, according to the usual starting method, power noise will be generated, affecting the user experience.

[0064] Therefore, through the above-mentioned embodiment, according to the adjusted main burner PPG signal, the collector voltage on the high-frequency switching device is collected as a voltage parameter. When the collector voltage is too high, the main burner PPG signal frequency is limited to reduce the main burner frequency, thereby reducing the collector voltage of the main burner resonant circuit.

[0065] In an embodiment of the first aspect of the present invention, in step S4, after adjusting the slave burner PPG signal, the method further comprises: Step S6, obtaining a voltage parameter of the high-frequency switch component, and confirming whether the voltage parameter is greater than a set voltage threshold.

[0066] In this embodiment, the high-frequency switching device is detected and the collector voltage on the high-frequency switching device is collected to obtain a voltage parameter, that is, the voltage parameter is the collector voltage of the high-frequency switching device, and it is determined whether the collector voltage is greater than a set voltage threshold.

[0067] Among them, the set voltage threshold value is in the range of 500V-1300V.

[0068] Step S6.10: If yes, the PPG signal frequency of the main burner is limited so that the high-frequency switch device of the main burner obtains the frequency of the main burner within the set voltage threshold range, and the slave burner dynamically follows the frequency of the main burner.

[0069] In this embodiment, when the collector voltage is greater than the set voltage threshold, the frequency of the output main burner PPG signal is limited to obtain the limited frequency of the main burner, and the frequency of the main burner is obtained, so that the slave burner dynamically follows the main burner frequency.

[0070] Step S6.20, using the frequency driving signal after limiting the main burner PPG signal, and then driving the high-frequency switching device to operate, so as to adjust the main burner resonant circuit.

[0071] In this embodiment, the frequency is limited to obtain the set drive signal, and the main burner target frequency drive signal is converted into the set frequency drive signal for driving. The high-frequency switching device is driven by the set drive signal to realize the protection operation of the high-frequency switching device, thereby regulating the main burner resonant circuit.

[0072] Among them, since the slave burner works in the on-off state of the AC power cycle, frequent startup will also generate noise, so the zero point of the AC power cycle is judged before the cycle is turned on, so that the slave burner is driven at a specific frequency before starting and crossing zero, so as to reduce the startup noise when the slave burner cycle is in the on state.

[0073] Among them, the drive signal from the furnace head is a 9V drive signal, and the drive signal after the mains cycle passes through zero is an 18V segmented drive signal.

[0074] In this embodiment, refer to Figure 2 , the steps from step S6 to step S6.20 can be performed using the frequency and synchronization detection circuit.

[0075] The frequency and synchronization detection circuit collects the collector voltage on the high-frequency switching device IGBT to obtain voltage parameters. Through the frequency and synchronization detection circuit, it is determined whether the collector voltage is greater than the set voltage threshold value within the range of 500V-1300V.

[0076] The device ensures the frequency of the master burner within the set voltage threshold range, and enables the slave burner to dynamically follow the frequency of the master burner.

[0077] The frequency driving signal after limiting the PPG signal of the main burner is used to drive the high-frequency switching device to operate, so as to adjust the main burner resonant circuit.

[0078] In order to ensure that the two burners maintain the same or similar oscillation frequency and maintain their respective output powers, the present invention needs to continuously adjust the intermittent time of the output drive signal. However, according to the usual starting method, power noise will be generated, affecting the user experience.

[0079] Therefore, through the above embodiment, according to the adjusted frequency PPG signal of the main burner, when the collector voltage is too high, the frequency of the main burner PPG signal is limited, so that the high-frequency switch device of the main burner is within the set voltage threshold range, the frequency of the main burner is ensured, and the slave burner dynamically follows the frequency of the main burner.

[0080] In an embodiment of the first aspect of the present invention, in step S3, adjusting the main furnace head PPG signal specifically includes: Step S3.1, when the main furnace power is less than the target power of the main furnace, the frequency of the main furnace PPG signal is increased according to the set target power until the main furnace power is within the range of the target power of the main furnace.

[0081] Step S3.20, determining whether the adjusted main burner PPG signal reaches the maximum limited pulse width frequency, and whether the main burner power is still less than the target power of the main burner.

[0082] Step S3.30: If yes, it is considered that the pots and pans placed at the main burner are offset, and the working status of the main burner is detected.

[0083] Step S3.40, when the slave burner power is consistent with the target power of the slave burner, the slave burner operates in the mains cycle on-off state, the slave burner oscillation frequency is less than the main burner oscillation frequency and the deviation frequency exceeds the maximum frequency in the set frequency range, according to the set frequency, adjust the slave burner to dynamically follow the main burner frequency.

[0084] In this embodiment, the main burner works continuously. When the first power is less than the target power of the main burner, the pulse width of the main burner PPG signal is increased or decreased according to the set frequency to ensure that the main burner power and frequency are within the set range of the target power and frequency of the main burner, or the main burner PPG signal reaches the maximum limit pulse width.

[0085] It should be noted that when the main burner power is not equal to the target power and frequency range of the main burner, the pulse width of the main burner PPG signal is increased or decreased according to the target frequency until the main burner power and frequency are within the target power and frequency range of the main burner.

[0086] In this embodiment, the target power and frequency of the main burner are regarded as the main target power and frequency, and the target power of the slave burner is regarded as the slave target power.

[0087] Confirm that the adjusted main burner PPG signal reaches the target frequency and whether the main burner power is still less than the main target power.

[0088] If so, it is considered that the pots placed at the main burner are offset. For the PPG control strategy, the target frequency of the main burner remains unchanged, so that the deviation frequency is maintained within the set frequency range, and the power of the main burner is the maximum power.

[0089] When the slave burner frequency is equal to the target frequency range of the master burner, the slave burner works on and off the mains cycle. When the slave burner oscillation frequency is not equal to the main burner oscillation frequency and the deviation frequency exceeds 1KHz, the pulse width of the slave burner PPG signal is increased or decreased according to the set frequency to make the deviation frequency within the set frequency range.

[0090] Through the above-mentioned embodiment, the placement of the pots on the current main burner is determined according to the PPG signal, power and frequency of the currently running main burner, and the power of the main burner is judged by taking the above-mentioned factors into consideration to adjust the main burner to determine whether to stop heating when the pot is moved, so as to prevent the burner coil from dry burning or generating noise.

[0091] In an embodiment of the first aspect of the present invention, in step S4, adjusting the mains power cycle on and off so that the slave burner power is within the target power range of the slave burner specifically includes: Step S4.1, when the oscillation frequency of the slave burner is not equal to the oscillation frequency of the master burner and the deviation frequency is outside the set frequency range, it is determined whether the frequency of the slave burner is consistent with the target frequency of the slave burner.

[0092] Step S4.11, if yes, obtain the sine wave cycle of the input AC power, operate the slave burner in the AC power cycle on / off state, maintain the deviation frequency within the set frequency range, adjust the AC power cycle on / off to maintain the slave burner rate and the slave burner within the target power range.

[0093] In this embodiment, when the slave burner frequency is equal to the target frequency range of the main burner, the slave burner operates with the AC power cycle on and off. When the slave burner oscillation frequency is not equal to the main burner oscillation frequency and the deviation frequency exceeds 1KHz, the pulse width of the slave burner PPG signal is increased or decreased according to the set frequency to make the deviation frequency within the set frequency range.

[0094] When the slave burner frequency is within the target frequency range of the slave burner, the sine wave cycle of the input mains is obtained, and the slave burner is switched to the mains cycle on / off state, with half a mains cycle as the power adjustment cycle. The pulse width of the slave burner PPG signal is maintained to make the slave burner oscillation frequency consistent with the main burner oscillation frequency to the greatest extent, maintain the deviation frequency within the set frequency range, and maintain the mains cycle on / off regulation at the same time, so that the slave burner power is within the target power range of the slave burner.

[0095] In an embodiment of the first aspect of the present invention, in step S4, adjusting the slave burner PPG signal specifically further comprises: Step S4.2, when the slave burner oscillation frequency is equal to the master burner oscillation frequency range, confirm whether the deviation frequency is close to the maximum value of the set frequency range, and whether the slave burner power is inconsistent with the target power of the slave burner.

[0096] Step S4.21, if yes, it is considered that the pots placed at the slave burner are offset, or there are characteristic differences between the pots at the main burner and the pots at the slave burner, and the oscillation frequency of the PPG signal of the slave burner remains unchanged.

[0097] In this embodiment, the oscillation frequency of the slave burner is not equal to the oscillation frequency of the main burner, the difference between the deviation frequency and the maximum frequency in the set frequency range is less than the set frequency threshold, that is, the deviation frequency is close to 1KHz, and the slave burner power is inconsistent with the target power of the slave burner.

[0098] When the above conditions are met, it is considered that the pots placed at the slave burner are offset, or that the pots on the main burner and the slave burner have greatly different characteristics. At this time, the oscillation frequency of the PPG signal of the slave burner is maintained unchanged.

[0099] In an embodiment of the first aspect of the present invention, in step S4, adjusting the slave burner PPG signal specifically further comprises: Step S4.3, when the oscillation frequency of the slave burner is equal to the oscillation frequency of the master burner, determine whether the slave burner power is less than the target power of the slave burner; Step S4.31, if so, the oscillation frequency of the slave burner PPG signal remains unchanged.

[0100] In this embodiment, when the oscillation frequency of the slave burner is not equal to the oscillation frequency of the main burner and the slave burner power is less than the target power of the slave burner, the oscillation frequency of the slave burner PPG signal is adjusted so that the oscillation frequency of the slave burner is within the range of the oscillation frequency of the main burner.

[0101] Through steps S4.1 to S4.31, the PPG control strategy of the slave burner is used to dynamically follow the oscillation frequency of the main burner, so that the deviation frequency is maintained within the set frequency range, preventing the mutual coupling between the burner coils from generating noise.

[0102] Reference Figure 3 The yellow waveform is the collector voltage waveform of the high-frequency switch device when the main burner is running, and the purple waveform is the AC cycle switch drive waveform when the slave burner is running; refer to Figure 4 , the yellow waveform is the collector voltage waveform frequency of the high-frequency switching device when the main burner is running, and the purple waveform is the collector voltage waveform frequency of the high-frequency switching device when the slave burner is running.

[0103] The noise reduction method provided by the present invention is applied to a single-tube multi-burner induction cooker with at least two resonant circuits. The main burner and the slave burner are determined according to the target frequency of each burner. The main burner adjusts the PPG width so that the target power is within the current operating power range. The slave burner adjusts the PPG width so that the same oscillation frequency or the difference frequency is maintained within the set frequency range as the main burner. The current operating power is ensured to be consistent with the target power by turning the main power cycle on and off. The collector voltage of the high-frequency switch tube is detected to automatically reduce the driving voltage of the high-frequency switch tube, so as to reduce the turn-on current of the high-frequency switch tube and reduce the starting noise. The problem that at least two induction coils of the multi-burner single-tube structure induction cooker in the prior art will generate obvious noise when working simultaneously is solved.

Claims

1. A noise reduction method for a single-tube multi-head induction cooker, characterized in that: The following steps are involved: S1: Obtain the target power and oscillation frequency of each burner; S2: Based on the target oscillation frequency of each burner, determine the main burner and the slave burner, wherein the burner with the lowest target oscillation frequency is used as the main burner, and its corresponding resonant circuit is the main resonant circuit, and the remaining burners are used as slave burners, and their corresponding resonant circuits are slave resonant circuits; S3: Acquire current signal through current detection; S4: According to the acquired current signal, a programmable pulse generator (PPG) mode is adjusted to control the operation of the master burner and the slave burner, so that the oscillation frequency of the master burner is synchronized with the oscillation frequency of the slave burner; S5: obtaining the current oscillation frequency of the main burner, and adjusting the PPG signal of the main burner according to the target power and frequency range of the main burner until the oscillation frequency and power thereof reach the target range; S6: setting the oscillation frequency of the master burner to the operating oscillation frequency of the slave burner, and adjusting the PPG signal of the slave burner based on the frequency deviation so that the frequency deviation is maintained within a set range; S7: Adjust the on / off state of the mains cycle to maintain the power from the burner within the set target power range.

2. The noise reduction method for a single-tube multi-burner induction cooker according to claim 1, characterized in that: After adjusting the main furnace head PPG signal, the method further includes: Detecting the highest voltage parameter of the high-frequency switch device and determining whether the voltage parameter is greater than a preset voltage threshold; If the voltage parameter is greater than the set voltage threshold, the peak voltage of the main furnace head PPG signal is reduced by frequency jittering technology, or the maximum voltage peak is limited according to the maximum voltage parameter of the switching tube to adjust the oscillation frequency of the main furnace head resonant circuit.

3. The noise reduction method for a single-tube multi-burner induction cooker according to claim 1, characterized in that: After adjusting the PPG signal from the furnace head, the method further includes: Detecting the highest voltage parameter of the high-frequency switch device and determining whether the voltage parameter is greater than a preset voltage threshold; If the voltage parameter is greater than the set voltage threshold, the peak voltage of the slave burner PPG signal is reduced by frequency jittering technology, or the maximum voltage peak is limited according to the maximum voltage parameter of the switch tube to adjust the oscillation frequency of the slave burner resonant circuit.

4. The noise reduction method for a single-tube multi-burner induction cooker according to claim 1, characterized in that: The adjustment process of the main furnace head PPG signal specifically includes: When the main burner frequency is not within the set main burner target frequency range, adjust the pulse width of the main burner PPG signal until the main burner frequency reaches the target frequency range; Determine whether the main furnace head PPG signal has reached the target frequency, and whether the main furnace head power is still less than the target power of the main furnace head; If the above conditions are met, it is considered that the pot placement position at the main burner is offset, and the working state of the slave burner is further detected; The frequency of the slave burner is set within the target power frequency range of the slave burner, and the slave burner is operated in the on-off state of the mains cycle; When the oscillation frequency of the slave burner is not equal to the oscillation frequency of the master burner and the frequency deviation exceeds the set range, the pulse width of the slave burner PPG signal is adjusted until the frequency deviation is maintained within the set range.

5. The noise reduction method for a single-tube multi-burner induction cooker according to claim 1, characterized in that: The adjusting of the mains power cycle to maintain the power from the burner within the set target power range specifically includes: When the oscillation frequency of the slave burner is not within the oscillation frequency range of the master burner and the frequency deviation exceeds the maximum value of the set frequency range, adjusting the oscillation frequency of the slave burner until it is within the oscillation frequency range of the master burner; If the above conditions are met, the slave burner is operated in the on-off state of the AC power cycle, the zero crossing point of the input AC power cycle is obtained to determine the power wave cycle, and the power is adjusted by changing the on-off state of the AC power cycle to maintain the slave burner power within the set target power range.

6. The noise reduction method for a single-tube multi-burner induction cooker according to claim 1, characterized in that: After adjusting the PPG signal from the burner, it also includes: Adjust the on / off state of the mains cycle. When the secondary furnace head works in the on / off state of the mains cycle, the mains cycle and the zero-crossing point are detected by the mains power supply cycle detection circuit; Before the start time of the cycle, the zero point of the mains cycle is determined first, so that the slave burner is driven at a specific frequency before the zero point to reduce the noise during startup; Among them, the drive signal from the furnace head is a 9V drive signal, and the drive signal is an 18V drive signal after the mains power cycle passes through zero.

7. The noise reduction method for a single-tube multi-burner induction cooker according to claim 3, characterized in that: The adjustment process of the slave burner PPG signal specifically includes: When the oscillation frequency of the slave burner is within the oscillation frequency range of the master burner, determining whether the power of the master burner is within the target power range of the slave burner; If the power of the main burner is not within the target power range of the slave burner, the power of the slave burner is maintained within the set target power range by increasing or decreasing the on / off cycle of the commercial power supply.

8. The noise reduction method for a single-tube multi-burner induction cooker according to claim 1, characterized in that: The process of determining the main burner and the slave burner specifically includes: Selecting the lowest target oscillation frequency from the target oscillation frequencies of the burners, taking the burner corresponding to the lowest target oscillation frequency as the main burner, and taking the lowest target oscillation frequency as the target frequency of the main burner; The remaining burners are regarded as slave burners, and the target frequency of the master burner is regarded as the target frequency of its corresponding slave burner.

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