CN110811312B - Cooking appliance and control device and control method thereof - Google Patents
Cooking appliance and control device and control method thereof Download PDFInfo
- Publication number
- CN110811312B CN110811312B CN201810892151.0A CN201810892151A CN110811312B CN 110811312 B CN110811312 B CN 110811312B CN 201810892151 A CN201810892151 A CN 201810892151A CN 110811312 B CN110811312 B CN 110811312B
- Authority
- CN
- China
- Prior art keywords
- voltage
- circuit
- ultrasonic transducer
- value
- pwm
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- A—HUMAN NECESSITIES
- A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
- A47J—KITCHEN EQUIPMENT; COFFEE MILLS; SPICE MILLS; APPARATUS FOR MAKING BEVERAGES
- A47J27/00—Cooking-vessels
- A47J27/08—Pressure-cookers; Lids or locking devices specially adapted therefor
- A47J27/0802—Control mechanisms for pressure-cookers
Abstract
The invention provides a cooking appliance and a control device and method thereof, wherein the control device of the cooking appliance comprises the following components: the rectifying circuit is used for rectifying alternating current output by the alternating current power supply to output pulsating direct current; the resonant circuit comprises an ultrasonic transducer and a resonant inductor which are connected in series; the input end of the excitation circuit is connected with the output end of the rectifying circuit, and the output end of the excitation circuit is connected with the resonant circuit; the voltage detection circuit is used for detecting the voltage at two ends of the ultrasonic transducer; the control circuit is respectively connected with the control end of the excitation circuit and the voltage detection circuit, and is used for outputting a driving signal to the excitation circuit according to the voltage at the two ends of the ultrasonic transducer and providing an excitation power supply for the resonance circuit through the excitation circuit, so that the frequency of the driving signal can be consistent with the current resonance frequency of the resonance circuit, and the ultrasonic transducer can work in the optimal state.
Description
Technical Field
The invention relates to the technical field of household appliances, in particular to a control device of a cooking appliance, the cooking appliance and a control method of the cooking appliance.
Background
When the existing cooking utensil (such as a pressure cooker) is used for cooking, because the pressure in the cooker is high, food cannot roll, nutrient substances are difficult to separate out, and the prepared porridge soup is light and has poor taste. For this reason, the related art well solves this problem using the ultrasonic vibration technique. By providing an alternating current signal with a certain frequency for the ultrasonic transducer, the ultrasonic transducer converts the electric energy into kinetic energy so as to enable water molecules in the pot to vibrate mechanically at a high frequency and transmit the water molecules to food, so that the food nutrient substances are decomposed. The ultrasonic transducer is an important core component of a cooking utensil, is made of piezoelectric materials, has capacitive impedance in electrical characteristics, generates reactive power by capacitive load, and has low output power factor, so that an inductive component is required to be matched with the capacitive load, and the ultrasonic driving system is in a resistive state when in work, namely the ultrasonic transducer and a resonant inductor form a resonant circuit.
At present, when an ultrasonic transducer is driven, an alternating-current point signal with fixed frequency is input into a resonant circuit, but in the vibration working process of the ultrasonic transducer, factors such as temperature, environment, vibration time, aging of vibration system elements and the like all affect electrical parameters of the ultrasonic transducer, the resonant frequency of the resonant circuit can drift, and the drift can increase reactance components in the circuit, increase reactive power and further deteriorate the working state, so that the risk of damaging the transducer elements exists.
Disclosure of Invention
The present invention is directed to solving, at least to some extent, one of the technical problems in the related art.
Therefore, a first object of the present invention is to provide a control device for a cooking appliance, which enables a frequency of a driving signal to be consistent with a resonant frequency of a resonant circuit, thereby realizing frequency tracking.
A second object of the present invention is to provide a cooking appliance.
A third object of the present invention is to provide a control method of a cooking appliance.
To achieve the above object, a first embodiment of the present invention provides a control device for a cooking appliance, including: the input end of the rectifying circuit is connected with an alternating current power supply, and the rectifying circuit is used for receiving alternating current output by the alternating current power supply and rectifying the alternating current to output pulsating direct current; a resonant circuit comprising an ultrasonic transducer and a resonant inductor connected in series; the input end of the excitation circuit is connected with the output end of the rectification circuit, and the output end of the excitation circuit is connected with the resonance circuit; the voltage detection circuit is used for detecting the voltage at two ends of the ultrasonic transducer; the control circuit is respectively connected with the control end of the excitation circuit and the voltage detection circuit, and the control circuit is used for outputting a driving signal to the excitation circuit according to the voltage at the two ends of the ultrasonic transducer so that the excitation circuit converts the pulsating direct current into alternating current to provide an excitation power supply for the resonance circuit.
According to the control device of the cooking utensil provided by the embodiment of the invention, the output frequency of the driving signal is adjusted by detecting the voltage change at two ends of the ultrasonic transducer, so that the output frequency is consistent with the resonant frequency of the resonant circuit under the current voltage, and the ultrasonic transducer is enabled to work in the optimal state.
In addition, the control device of the cooking appliance according to the embodiment of the invention may further have the following additional technical features:
according to an embodiment of the present invention, the control apparatus of a cooking appliance further includes: an impedance transformer having a primary side connected to an output of the excitation circuit and a secondary side connected in series with the resonant circuit.
According to an embodiment of the present invention, the control apparatus of the cooking appliance further includes: one end of the first capacitor is connected with a first pole of the output end of the rectifying circuit, the other end of the first capacitor is connected with a second pole of the output end of the rectifying circuit, and the first capacitor is used for smoothing the pulsating direct current.
According to one embodiment of the invention, the control circuit comprises: the output end of the half-bridge driver is connected with the control end of the excitation circuit; the controller is provided with a first PWM pin, a second PWM pin and an AD pin, the first PWM pin is connected with a first input end of the half-bridge driver, the second PWM pin is connected with a second input end of the half-bridge driver, the AD pin is connected with the voltage detection circuit, the controller outputs a first control signal through the first PWM pin and outputs a second control signal through the second PWM pin according to the voltage at two ends of the ultrasonic transducer, and the first control signal and the second control signal are complementary; wherein the half-bridge driver converts the first control signal into a first driving signal and converts the second control signal into a second driving signal, wherein the driving signals include the first driving signal and the second driving signal.
According to one embodiment of the invention, the excitation circuit comprises: a gate of the first switching tube is connected to a first output terminal of the half-bridge driver, a drain of the first switching tube is connected to a first pole of an output terminal of the rectifying circuit and forms a first node, and a source of the first switching tube is connected to one end of a primary side of the impedance converter and forms a second node, wherein the half-bridge driver outputs the first driving signal through the first output terminal; a second capacitor, a first end of which is connected to the first node, and the other end of which is connected to the other end of the primary side of the impedance transformer, and forms a third node; a gate of the second switching tube is connected to a second output end of the half-bridge driver, a drain of the second switching tube is connected to the second node, a source of the second switching tube is connected to a second pole of the output end of the rectifying circuit, and a fourth node is formed, wherein the half-bridge driver outputs the second driving signal through the second output end; and one end of the third capacitor is connected with the third node, and the other end of the third capacitor is connected with the fourth node.
According to an embodiment of the present invention, the voltage detection circuit includes: the first inductor and the resonance inductor form a mutual inductor, and one end of the first inductor is grounded; the anode of the first diode is connected with the other end of the first inductor, and the cathode of the first diode is connected with the AD pin of the controller; one end of the first resistor is connected with the cathode of the first diode, and the other end of the first resistor is grounded; a fourth capacitor connected in parallel with the first resistor.
According to an embodiment of the invention, the controller comprises a PWM generator comprising a register, the controller being particularly adapted to: adjusting the PWM value in the register according to the voltage at two ends of the ultrasonic transducer; and outputting the first control signal and the second control signal according to the adjusted PWM value.
According to an embodiment of the present invention, when the controller adjusts the PWM value in the register according to the voltage across the ultrasonic transducer, the controller is specifically configured to: judging whether the voltage at two ends of the ultrasonic transducer is greater than a preset voltage or not; if the voltage at the two ends of the ultrasonic transducer is equal to the preset voltage, keeping the PWM value in the register unchanged; if the voltage at two ends of the ultrasonic transducer is greater than the preset voltage, performing difference operation on the PWM value and a first preset value when the PWM value is greater than a preset minimum value, and keeping the PWM value unchanged when the PWM value is less than or equal to the preset minimum value; and if the voltage at the two ends of the ultrasonic transducer is smaller than the preset voltage, performing summation operation on the PWM value and a second preset value when the PWM value is smaller than a preset maximum value, and keeping the PWM value unchanged when the PWM value is larger than or equal to the preset maximum value.
In order to achieve the above object, a second aspect of the present invention provides a cooking appliance, including the control device of the cooking appliance according to the above embodiment.
According to the cooking device provided by the embodiment of the invention, by adopting the control device of the cooking appliance provided by the embodiment, the output frequency of the driving signal is adjusted by detecting the voltage change at the two ends of the ultrasonic transducer, so that the output frequency of the driving signal is consistent with the resonant frequency of the resonant circuit under the current voltage, and the ultrasonic transducer is enabled to work in the optimal state.
In order to achieve the above object, a third aspect of the present invention provides a control method for a cooking appliance, the cooking appliance including an excitation circuit and a resonant circuit, wherein the resonant circuit includes an ultrasonic transducer and a resonant inductor connected in series, the control method including: when the cooking appliance performs cooking work, detecting the voltage at two ends of the ultrasonic transducer in real time; and outputting a driving signal to the excitation circuit according to the voltage at two ends of the ultrasonic transducer so that the excitation circuit provides an excitation power supply for the resonant circuit.
According to the control method of the cooking utensil provided by the embodiment of the invention, the output frequency of the driving signal is adjusted by detecting the voltage change at two ends of the ultrasonic transducer, so that the output frequency is consistent with the resonant frequency of the resonant circuit under the current voltage, and the ultrasonic transducer is enabled to work in the optimal state.
In addition, the control method of the cooking appliance according to the embodiment of the invention may further have the following additional technical features:
according to an embodiment of the present invention, outputting the driving signal according to the voltage across the ultrasonic transducer using a PWM generator includes: adjusting a PWM value in a register of the PWM generator according to the voltage at two ends of the ultrasonic transducer; and outputting the driving signal according to the adjusted PWM value.
According to an embodiment of the present invention, the adjusting the PWM value in the register of the PWM generator according to the voltage across the ultrasonic transducer comprises: judging whether the voltage at two ends of the ultrasonic transducer is greater than a preset voltage or not; if the voltage at the two ends of the ultrasonic transducer is equal to the preset voltage, keeping the PWM value unchanged; if the voltage at two ends of the ultrasonic transducer is greater than the preset voltage, performing difference operation on the PWM value and a first preset value when the PWM value is greater than a preset minimum value, and keeping the PWM value unchanged when the PWM value is less than or equal to the preset minimum value; and if the voltage at the two ends of the ultrasonic transducer is smaller than the preset voltage, performing summation operation on the PWM value and a second preset value when the PWM value is smaller than a preset maximum value, and keeping the PWM value unchanged when the PWM value is larger than or equal to the preset maximum value.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
The foregoing and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
fig. 1 is a block diagram of a control apparatus of a cooking appliance according to an embodiment of the present invention;
FIG. 2 is a graph of the output frequency of the drive signal versus the output power of the ultrasonic transducer according to one embodiment of the present invention;
fig. 3 is a circuit topology diagram of a control apparatus of a cooking appliance according to an embodiment of the present invention;
FIG. 4 is a flow chart of the operation of a controller according to one embodiment of the present invention;
fig. 5 is a block diagram of a cooking appliance according to an embodiment of the present invention;
fig. 6 is a flowchart of a control method of a cooking appliance according to an embodiment of the present invention.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.
A cooking appliance, a control apparatus and a control method thereof according to an embodiment of the present invention will be described with reference to fig. 1 to 6.
Fig. 1 is a block diagram of a control apparatus of a cooking appliance according to an embodiment of the present invention. As shown in fig. 1, the control device 100 includes a rectifier circuit 10, a resonance circuit 20, an excitation circuit 30, a voltage detection circuit 40, and a control circuit 50.
Referring to fig. 1, an input end of a rectifier circuit 10 is connected to an alternating current power supply AC, and the rectifier circuit 10 is configured to receive an alternating current output by the alternating current power supply AC and rectify the alternating current to output a pulsating direct current. The resonant circuit 20 includes an ultrasonic transducer Z1 and a resonant inductor L1 connected in series. The input end of the excitation circuit 30 is connected to the output end of the rectification circuit 10, and the output end of the excitation circuit 30 is connected to the resonance circuit 20. The voltage detection circuit 40 is used for detecting the voltage of the ultrasonic transducer Z1. The control circuit 50 is respectively connected with the control terminal of the excitation circuit 30 and the voltage detection circuit 40, and the control circuit 50 is used for outputting a driving signal to the excitation circuit 30 according to the voltage of the ultrasonic transducer Z1, so that the excitation circuit 30 converts the pulsating direct current into an alternating current to provide an excitation power supply for the resonance circuit 20.
In this embodiment, the ultrasonic transducer Z1 is electrically characterized as a capacitive impedance, and is connected in series with the resonant inductor L1 to form the resonant circuit 20, wherein the resonant frequency is equal to
The resonant circuit 20 has a frequency-selective characteristic, and when the frequency of the driving signal is the same as the resonant frequency of the resonant circuit 20, the ultrasonic transducer Z1 operates in an optimum state with maximum output power. As shown in fig. 2, as the frequency F of the drive signal output by the control circuit 50 is closer to the resonance frequency F0 of the resonance circuit 20, the output power is larger; the further away the frequency F is from the resonant frequency F0, the smaller the output power.
In operation, in order to prevent the frequency F from falling into a frequency region lower than F0, a minimum frequency value F2 may be set in the control strategy of the PWM generator in the internal software design of the control circuit 50, as shown in fig. 3, where the frequency generated by the PWM generator is greater than or equal to F2.
However, the capacitive impedance of the ultrasonic transducer Z1 is not constant, and its equivalent capacitance value varies with temperature, environment, vibration time, and aging of vibration system components. After the equivalent capacitance value C is changed, the formula is followed
The resonance frequency of the available resonance circuit is shifted, the reactive component of the resonance circuit is increased due to the shift, the reactive power is increased, if a driving signal with fixed frequency is adopted, the frequency of the driving signal is not matched with the current resonance frequency of the resonance circuit 20, the working state of the ultrasonic transducer Z1 is deteriorated, and the service life of the ultrasonic transducer Z1 is greatly shortened.
When the resonant circuit formed by the ultrasonic transducer Z1 and the resonant inductor L1 operates, the larger the output power of the ultrasonic transducer Z1 is, the larger the current flowing through the resonant circuit is, and the larger the voltage across the ultrasonic transducer Z1 is. Therefore, the control device of the embodiment of the invention can indirectly detect the output power of the ultrasonic transducer Z1 by detecting the voltage at the two ends of the ultrasonic transducer through the voltage detection circuit, and further outputs a corresponding driving signal to the exciting circuit through the control circuit according to the voltage so as to provide an exciting power supply for the resonant circuit, and the frequency of the driving signal is consistent with the current resonant frequency of the resonant circuit, so that the ultrasonic transducer Z1 can work in the optimal state, and the cooking effect of the cooking appliance can be improved.
In one embodiment of the present invention, as shown in fig. 3, the rectifier circuit 10 is a bridge rectifier circuit, which is composed of diodes D1, D2, D3, D4, and is used to convert ac power into pulsating dc power.
Further, as shown in fig. 3, the control device 100 may further include an impedance transformer T1, a primary side of the impedance transformer T1 being connected to the output terminal of the excitation circuit 30, and a secondary side of the impedance transformer T1 being connected in series with the resonance circuit 20. The impedance converter T1 is arranged to convert the load of the ultrasonic transducer Z1 into an optimal load, so that the output power of the ultrasonic transducer Z1 reaches the preset rated power.
Further, as shown in fig. 3, the control device 100 may further include a first capacitor C1, one end of the first capacitor C1 is connected to a first pole of the output terminal of the rectifier circuit 10, the other end of the first capacitor C2 is connected to a second pole of the output terminal of the rectifier circuit 10, and the first capacitor C1 is used for smoothing the pulsating dc current.
In one embodiment of the present invention, the driving signals output by the control circuit 50 include a first driving signal and a second driving signal, wherein the first driving signal and the second driving signal are complementary. It should be understood that complementary means that when either one of the first drive signal and the second drive signal is high, the other signal is low.
In this embodiment, as shown in fig. 3, the control circuit 50 includes a half-bridge driver 51 and a controller 52. Wherein, the output terminal of the half-bridge driver 51 is connected to the control terminal of the excitation circuit 30; the controller 52 has a first PWM pin PWMP, a second PWM pin PWMN, and an AD pin Vad, the first PWM pin PWMP is connected to the first input terminal of the half-bridge driver 51, the second PWM pin PWMN is connected to the second input terminal of the half-bridge driver 51, the AD pin Vad is connected to the voltage detection circuit 40, the controller 40 outputs a first control signal through the first PWM pin PWMP, and outputs a second control signal through the second PWM pin PWMN, so that the half-bridge driver 51 generates the first driving signal and the second driving signal according to the first control signal and the second control signal, where the first control signal and the second control signal are complementary.
Further, as shown in fig. 3, the driving circuit 30 includes a first switch Q1, a second capacitor C2, a second switch Q2, and a third capacitor C3.
The gate of the first switching tube Q1 is connected to the first output terminal of the half-bridge driver 51, the drain of the first switching tube Q1 is connected to the first pole of the output terminal of the rectifying circuit 10 and forms a first node a, and the source of the first switching tube Q1 is connected to one end of the primary side of the impedance transformer T1 and forms a second node b. A first terminal of the second capacitor C2 is connected to the first node a, and the other terminal of the second capacitor C2 is connected to the other terminal of the primary side of the impedance transformer T1, and forms a third node C. The gate of the second switch Q2 is connected to the second output terminal of the half-bridge driver 51, the drain of the second switch Q2 is connected to the second node b, and the source of the second switch Q2 is connected to the second pole of the output terminal of the rectifier circuit 10, and forms a fourth node d. One terminal of the third capacitor C3 is connected to the third node C, and the other terminal of the third capacitor C3 is connected to the fourth node d.
In this embodiment, the gate of the first switch Q1 and the gate of the second switch Q2 are control terminals of the driving circuit 30, the half-bridge driver 51 outputs the first driving signal through a first output terminal, and the half-bridge driver 51 outputs the second driving signal through a second output terminal.
Further, as shown in fig. 2, the voltage detection circuit 40 includes a first inductor L2, a first diode D5, a first resistor R1, and a fourth capacitor C4. The first inductor L2 and the resonant inductor L1 form a mutual inductor LT1, and one end of the first inductor L2 is grounded; an anode of the first diode D5 is connected to the other end of the first inductor L2, and a cathode of the first diode D5 is connected to an AD pin Vad of the controller 52; one end of the first resistor R1 is connected to the cathode of the first diode D5, and the other end of the first resistor R1 is grounded; the fourth capacitor C4 is connected in parallel with the first resistor R1.
In particular, referring to fig. 3, when there is a voltage across resonant inductor L1, first inductor L2 acts as the secondary winding of transformer coil LT1, across which a transformer voltage is developed, which is an ac voltage. The ac voltage is rectified by the first diode D5, filtered by the fourth capacitor C4, and then outputted as a smooth dc level signal to the AD pin Vad of the controller 52.
Of course, the voltage detection circuit 40 may also adopt other circuits, such as connecting wires directly led out from two ends of the ultrasonic transducer Z1, and a voltage sensor is connected between the connecting wires.
In an embodiment of the present invention, the controller 52 includes a PWM generator including a register, and the controller 52 is specifically configured to adjust a PWM value in the register according to a voltage across the ultrasonic transducer Z1, and further output a first control signal and a second control signal according to the adjusted PWM value.
When the controller 52 adjusts the PWM value in the register according to the voltage across the ultrasonic transducer Z1, it is specifically configured to: judging whether the voltage at two ends of the ultrasonic transducer Z1 is greater than a preset voltage or not; if the voltage at the two ends of the ultrasonic transducer Z1 is equal to the preset voltage, keeping the PWM value in the register unchanged; if the voltage at the two ends of the ultrasonic transducer Z1 is greater than the preset voltage, when the PWM value is greater than the preset minimum value, performing difference operation on the PWM value and the first preset value, and when the PWM value is less than or equal to the preset minimum value, keeping the PWM value unchanged; if the voltage across the ultrasonic transducer Z1 is less than the preset voltage, the PWM value is summed with a second preset value when the PWM value is less than the preset maximum value, and the PWM value is maintained when the PWM value is greater than or equal to the preset maximum value.
In this embodiment, the preset voltage, the preset minimum value and the preset maximum value can be set according to the electrical parameters of the ultrasonic transducer Z1 and the resonance inductor L1. The first preset value and the second preset value are both greater than 0, and values of the first preset value and the second preset value can be set according to needs, and if the first preset value is equal to the second preset value, the values are both 1, and certainly, the first preset value and the second preset value can also be unequal.
It should be noted that a preset PWM value may be pre-stored in the register, so that when the voltage across the ultrasonic transducer Z1 is not detected, the PWM generator outputs the first control signal and the second control signal according to the preset PWM value.
The operation of the control device 100 according to an embodiment of the present invention will be described with reference to fig. 2 to 4.
Referring to fig. 3, the controller 52 outputs two complementary PWM square wave signals (i.e., a first control signal and a second control signal), the square wave signals have a high level amplitude of 5V and a low level amplitude of 0V, and after passing through the half-bridge driver 51, the square wave signals are converted to output a square wave signal having a high level of 15V and a low level of 0V, and are respectively sent to the gate of the first switching tube Q1 and the gate of the second switching tube Q2.
When the PWMP pin of the controller 52 outputs a high level of 5V, the PWMN pin outputs a low level of 0V, and after passing through the half-bridge driver 51, the voltage between GS of the first switching tube Q1 is 15V, the first switching tube Q1 is turned on, the second switching tube Q2 is turned off, the DS pin of the first switching tube Q1 is short-circuited, the DS pin of the first switching tube Q1, the primary side of the impedance transformer T1 and the second capacitor C2 form a loop to charge and discharge the second capacitor C2, the voltage of the primary winding (i.e., the primary side) of the impedance transformer T1 is positive left and negative right, and the voltage of the secondary winding (i.e., the secondary side) is positive left and negative right to supply power to the resonant circuit 20.
When the PWMP pin of the controller 52 outputs a low level of 0V, the PWMN pin outputs a low level of 5V, after passing through the half-bridge driver 51, the voltage between GS of the second switching tube Q2 is 15V, the second switching tube Q2 is turned on, the first switching tube Q1 is turned off, so that the DS pin of the second switching tube Q2 is short-circuited, the DS pin of the second switching tube Q2, the primary side of the impedance transformer T1 and the third capacitor C3 form a loop to charge and discharge the third capacitor C3, the primary winding voltage of the impedance transformer T1 is negative left and positive right, and the secondary winding outputs a voltage positive left and negative right to power the resonant circuit 20.
In one embodiment, when the cooking appliance is in operation, the PWM generator of the controller 52 outputs a PWM square wave signal with a certain frequency, and outputs an ac signal with the certain frequency through the half-bridge driver 51 to drive the resonant circuit 20 consisting of the ultrasonic transducer Z1 and the resonant inductor L1. The voltage across the primary winding (resonant inductor L1) is detected by the secondary winding (i.e. the first inductor L2) of the transformer LT1, rectified by the first diode D5, rectified and filtered by the fourth capacitor C4, and then a smooth dc voltage signal is output to the Vad pin of the controller 52, and the controller 52 periodically starts AD analog-to-digital conversion to read the AD value of the pin.
Further, if the AD value of the current Vad pin is equal to the preset AD value, the current PWM value in the register is kept unchanged. If the AD value of the current Vad pin is larger than the preset AD value, further judging the relation between the current PWM value and the preset minimum value, and if the current PWM value is larger than the preset minimum value, subtracting 1 from the current PWM value; otherwise, keeping the current PWM value unchanged. If the AD value of the current Vad pin is smaller than the preset AD value, the relation between the current PWM value and the preset maximum value is further judged, and if the current PWM value is smaller than the preset maximum value, the current PWM value is added by 1; otherwise, keeping the current PWM value unchanged.
As an example, the clock frequency Fosc of the controller 52 is 16MHz, and the PWM pin of the controller 52 outputs the frequency f of the first control signal and the second control signal, Fosc/2x, where x is the PWM value in the register. The predetermined AD value is 200, the predetermined minimum value 228, and the predetermined maximum value 320. For example, when the PWM value is 286, the PWM pin of the controller 52 outputs the first control signal and the second control signal with the frequency f 16000/(2 286) ═ 28KHz, and the output power of the ultrasonic transducer Z1 is 50 watts, as shown in fig. 4.
In this example, the timer program in the controller 52 will set the 10 ms flag bit every 10 ms, and the controller 52 performs the following steps:
s1, judging whether the 10 millisecond zone bit is set to be 1, if not, returning to the next period judgment, if so, executing the step E1;
e1, clearing the flag bit of 10 milliseconds;
e2, starting AD analog-to-digital conversion to read the AD value of the pin Vad;
and S2, judging whether the AD value is equal to the preset AD value.
If the AD value is 200 and is equal to the preset AD value, the fact that the frequency of the PWM square wave output by the current controller is consistent with the resonant frequency of the resonant circuit is shown, the frequency of the PWM square wave output by the controller does not need to be adjusted, the current PWM value is kept 286 unchanged, and the next period is returned to be judged.
Due to the influence of temperature or other environmental factors, the equivalent capacitance of the ultrasonic transducer Z1 changes, and thus the resonant frequency F0 of the resonant circuit 20 changes.
As shown in fig. 2, before the change, the characteristic curve of the resonant circuit 20 is an SV1 curve, the resonant frequency thereof is F0, the PWM value in the register of the PWM generator of the controller 52 is 286, according to the formula F Fosc/2x, the frequency of the output signal of the PWM pin is equal to 28KHz, that is, the frequency F2 shown in fig. 2, the power output by the ultrasonic transducer Z1 is 50W, and the AD value obtained by analog-to-digital conversion of the Vad pin of the controller 52 is 200.
As shown in fig. 2, after the change, the resonant frequency of the resonant circuit 20 shifts to F0', the characteristic curve thereof is SV2 curve, and at this time, if the PWM pin of the controller 52 still outputs the output signal with the frequency of 28KHz, i.e. the frequency F2 shown in fig. 2, the output power of the ultrasonic transducer Z1 rises to 53W, and at this time, the AD value rises from 200 to 205.
S3, when the AD value is not equal to the preset AD value, judging whether the AD value is larger than the preset AD value;
s4, if the AD value is larger than the preset AD value, further judging whether the current PWM value is larger than the preset minimum value;
e3, if the current PWM value is larger than the preset minimum value, subtracting 1 from the current PWM value;
and if the current PWM value is smaller than or equal to the preset minimum value, returning to perform the next period judgment.
S5, if the AD value is smaller than the preset AD value, further judging whether the current PWM value is smaller than the preset maximum value;
e3, if the current PWM value is smaller than the preset maximum value, adding 1 to the current PWM value;
and if the current PWM value is larger than or equal to the preset maximum value, returning to perform the next period judgment.
The above process is repeated.
According to the above equation f — Fosc/2x, the smaller the PWM value, the greater the frequency of the output signal of the controller 52, as shown in fig. 2, when the frequency of the output signal of the controller 52 reaches f 2', the output power of the ultrasonic transducer Z1 after the change is reduced to 50W, and the ultrasonic transducer Z1 returns to the optimal operation state again, thereby implementing the automatic tracking of the frequency.
In summary, according to the control device of the cooking appliance of the embodiment of the invention, the output frequency of the control signal is adjusted to change by detecting the voltage change at the two ends of the ultrasonic transducer, so that the output frequency is consistent with the resonant frequency of the current resonant circuit, the ultrasonic transducer is enabled to work in the optimal state, thereby realizing the automatic tracking of the frequency and effectively prolonging the service life of the product. .
Fig. 5 is a block diagram of a cooking appliance according to an embodiment of the present invention.
As shown in fig. 5, the cooking appliance 1000 includes the control device 100 of the cooking appliance of the above embodiment.
According to the cooking device provided by the embodiment of the invention, the control device of the cooking appliance is adopted, and the output frequency of the control signal is adjusted to change by detecting the voltage change at the two ends of the ultrasonic transducer, so that the output frequency is consistent with the resonant frequency of the resonant circuit under the current voltage, and the ultrasonic transducer is enabled to work in the optimal state.
In addition, other configurations and functions of the cooking utensil according to the above embodiment of the present invention are known to those skilled in the art, and are not described herein in detail to reduce redundancy.
Fig. 6 is a flowchart of a control method of a cooking appliance according to an embodiment of the present invention.
In this embodiment, the cooking appliance comprises an excitation circuit and a resonant circuit, wherein the resonant circuit comprises an ultrasonic transducer and a resonant inductor connected in series.
As shown in fig. 6, the control method includes the steps of:
and S101, detecting the voltage at two ends of the ultrasonic transducer in real time when the cooking appliance performs cooking.
And S102, outputting a driving signal to an excitation circuit according to the voltage at two ends of the ultrasonic transducer so that the excitation circuit provides an excitation power supply for the resonant circuit.
Specifically, a PWM generator may be used to output a driving signal according to a voltage across the ultrasonic transducer, including: adjusting a PWM value in a register of a PWM generator according to the voltage at two ends of the ultrasonic transducer; and outputting a driving signal according to the adjusted PWM value.
The method for adjusting the PWM value in the register of the PWM generator according to the voltage at two ends of the ultrasonic transducer comprises the following steps: judging whether the voltage at two ends of the ultrasonic transducer is greater than a preset voltage or not; if the voltage at the two ends of the ultrasonic transducer is equal to the preset voltage, keeping the PWM value unchanged; if the voltage at the two ends of the ultrasonic transducer is greater than the preset voltage, when the PWM value is greater than the preset minimum value, performing difference operation on the PWM value and the first preset value, and when the PWM value is less than or equal to the preset minimum value, keeping the PWM value unchanged; and if the voltage at the two ends of the ultrasonic transducer is smaller than the preset voltage, performing AND operation on the PWM value and a second preset value when the PWM value is smaller than a preset maximum value, and keeping the PWM value unchanged when the PWM value is larger than or equal to the preset maximum value.
For other specific embodiments of the control method of the cooking appliance according to the embodiment of the present invention, reference may be made to specific embodiments of the control device of the cooking appliance according to the above-described embodiment of the present invention.
According to the control method of the cooking utensil provided by the embodiment of the invention, the change of the output frequency of the driving signal is adjusted by detecting the voltage change at two ends of the ultrasonic transducer, so that the output frequency of the driving signal is consistent with the resonant frequency of the resonant circuit under the current voltage, and the ultrasonic transducer is enabled to work in the optimal state.
In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the invention.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.
Claims (10)
1. A control device for a cooking appliance, comprising:
the input end of the rectifying circuit is connected with an alternating current power supply, and the rectifying circuit is used for receiving alternating current output by the alternating current power supply and rectifying the alternating current to output pulsating direct current;
a resonant circuit comprising an ultrasonic transducer and a resonant inductor connected in series;
the input end of the excitation circuit is connected with the output end of the rectification circuit, and the output end of the excitation circuit is connected with the resonance circuit;
the voltage detection circuit is used for detecting the voltage at two ends of the ultrasonic transducer;
the control circuit is respectively connected with the control end of the excitation circuit and the voltage detection circuit, and is used for outputting a driving signal to the excitation circuit according to the voltage at the two ends of the ultrasonic transducer so that the excitation circuit converts the pulsating direct current into alternating current to provide an excitation power supply for the resonance circuit;
the control circuit comprises a PWM generator comprising a register, and is specifically configured to:
adjusting the PWM value in the register according to the voltage at two ends of the ultrasonic transducer;
outputting the driving signal according to the adjusted PWM value;
when the controller adjusts the PWM value in the register according to the voltage at the two ends of the ultrasonic transducer, the controller is specifically configured to:
judging whether the voltage at two ends of the ultrasonic transducer is greater than a preset voltage or not;
if the voltage at the two ends of the ultrasonic transducer is equal to the preset voltage, keeping the PWM value in the register unchanged;
if the voltage at two ends of the ultrasonic transducer is greater than the preset voltage, performing difference operation on the PWM value and a first preset value when the PWM value is greater than a preset minimum value, and keeping the PWM value unchanged when the PWM value is less than or equal to the preset minimum value;
and if the voltage at the two ends of the ultrasonic transducer is smaller than the preset voltage, performing summation operation on the PWM value and a second preset value when the PWM value is smaller than a preset maximum value, and keeping the PWM value unchanged when the PWM value is larger than or equal to the preset maximum value.
2. The control device of the cooking appliance according to claim 1, further comprising:
an impedance transformer having a primary side connected to an output of the excitation circuit and a secondary side connected in series with the resonant circuit.
3. The control device of the cooking appliance according to claim 1, further comprising:
one end of the first capacitor is connected with a first pole of the output end of the rectifying circuit, the other end of the first capacitor is connected with a second pole of the output end of the rectifying circuit, and the first capacitor is used for smoothing the pulsating direct current.
4. The control device of a cooking appliance according to claim 1, wherein the control circuit comprises:
the output end of the half-bridge driver is connected with the control end of the excitation circuit;
the controller is provided with a first PWM pin, a second PWM pin and an AD pin, the first PWM pin is connected with a first input end of the half-bridge driver, the second PWM pin is connected with a second input end of the half-bridge driver, the AD pin is connected with the voltage detection circuit, the controller outputs a first control signal through the first PWM pin and outputs a second control signal through the second PWM pin according to the voltage at two ends of the ultrasonic transducer, and the first control signal and the second control signal are complementary;
wherein the half-bridge driver converts the first control signal into a first driving signal and converts the second control signal into a second driving signal, wherein the driving signals include the first driving signal and the second driving signal.
5. The control device of the cooking appliance according to claim 4, wherein the energizing circuit comprises:
a gate of the first switching tube is connected to a first output terminal of the half-bridge driver, a drain of the first switching tube is connected to a first pole of an output terminal of the rectifying circuit and forms a first node, and a source of the first switching tube is connected to one end of a primary side of the impedance converter and forms a second node, wherein the half-bridge driver outputs the first driving signal through the first output terminal;
a second capacitor, a first end of which is connected to the first node, and the other end of which is connected to the other end of the primary side of the impedance transformer, and forms a third node;
a gate of the second switching tube is connected to a second output end of the half-bridge driver, a drain of the second switching tube is connected to the second node, a source of the second switching tube is connected to a second pole of the output end of the rectifying circuit, and a fourth node is formed, wherein the half-bridge driver outputs the second driving signal through the second output end;
and one end of the third capacitor is connected with the third node, and the other end of the third capacitor is connected with the fourth node.
6. The control device of the cooking appliance according to claim 4, wherein the voltage detection circuit comprises:
the first inductor and the resonance inductor form a mutual inductor, and one end of the first inductor is grounded;
the anode of the first diode is connected with the other end of the first inductor, and the cathode of the first diode is connected with the AD pin of the controller;
one end of the first resistor is connected with the cathode of the first diode, and the other end of the first resistor is grounded;
a fourth capacitor connected in parallel with the first resistor.
7. The control device of a cooking appliance according to claim 6, wherein the controller comprises a PWM generator comprising a register, the controller being specifically configured to:
adjusting the PWM value in the register according to the voltage at two ends of the ultrasonic transducer;
and outputting the first control signal and the second control signal according to the adjusted PWM value.
8. Cooking appliance, characterized in that it comprises a control device of a cooking appliance according to any one of claims 1 to 7.
9. A control method of a cooking appliance, characterized in that the control method is used for a control device of the cooking appliance according to claim 1, the control method comprising the steps of:
when the cooking appliance performs cooking work, detecting the voltage at two ends of the ultrasonic transducer in real time;
adjusting a PWM value in a preset register according to the voltage at two ends of the ultrasonic transducer, and outputting a driving signal to the excitation circuit according to the adjusted PWM value so that the excitation circuit provides an excitation power supply for the resonance circuit;
wherein, the adjusting of the PWM value in the preset register according to the voltage at the two ends of the ultrasonic transducer comprises:
judging whether the voltage at two ends of the ultrasonic transducer is greater than a preset voltage or not;
if the voltage at the two ends of the ultrasonic transducer is equal to the preset voltage, keeping the PWM value unchanged;
if the voltage at two ends of the ultrasonic transducer is greater than the preset voltage, performing difference operation on the PWM value and a first preset value when the PWM value is greater than a preset minimum value, and keeping the PWM value unchanged when the PWM value is less than or equal to the preset minimum value;
and if the voltage at the two ends of the ultrasonic transducer is smaller than the preset voltage, performing summation operation on the PWM value and a second preset value when the PWM value is smaller than a preset maximum value, and keeping the PWM value unchanged when the PWM value is larger than or equal to the preset maximum value.
10. The method for controlling a cooking appliance according to claim 9, wherein outputting the driving signal using a PWM generator, the outputting the driving signal according to the voltage across the ultrasonic transducer comprises:
adjusting a PWM value in a register of the PWM generator according to the voltage at two ends of the ultrasonic transducer;
and outputting the driving signal according to the adjusted PWM value.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810892151.0A CN110811312B (en) | 2018-08-07 | 2018-08-07 | Cooking appliance and control device and control method thereof |
| PCT/CN2019/092900 WO2020029695A1 (en) | 2018-08-07 | 2019-06-26 | Cooking appliance and ultrasonic oscillator drive control method and apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810892151.0A CN110811312B (en) | 2018-08-07 | 2018-08-07 | Cooking appliance and control device and control method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110811312A CN110811312A (en) | 2020-02-21 |
| CN110811312B true CN110811312B (en) | 2021-07-20 |
Family
ID=69533842
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201810892151.0A Active CN110811312B (en) | 2018-08-07 | 2018-08-07 | Cooking appliance and control device and control method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110811312B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113867180B (en) * | 2020-06-30 | 2023-02-28 | 佛山市顺德区美的电热电器制造有限公司 | Drive control circuit, control method of drive control circuit and household electrical appliance |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106137072A (en) * | 2015-04-08 | 2016-11-23 | 夏宜智 | Commercial ultrasound ripple washes dish dish-washing machine |
| CN106961229A (en) * | 2017-04-06 | 2017-07-18 | 深圳拓邦股份有限公司 | A kind of self adaptation washing facility numerical control supersonic driver |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5443344A (en) * | 1977-09-13 | 1979-04-05 | Brother Ind Ltd | Induction heating apparatus |
| CN100462116C (en) * | 2004-07-29 | 2009-02-18 | 上海交通大学 | Power supersonic transducer exciting circuit |
| TW201318564A (en) * | 2011-06-15 | 2013-05-16 | Green Mountain Coffee Roasters Inc | Beverage formation apparatus and method using vibratory energy |
| CN103607799B (en) * | 2013-11-28 | 2016-02-03 | 美的集团股份有限公司 | Electromagnetic induction heater and electromagnetic oven |
| CN104795984B (en) * | 2014-01-21 | 2017-09-26 | 华为技术有限公司 | Power supply changeover device |
| CN106162970B (en) * | 2015-04-07 | 2022-09-06 | 佛山市顺德区美的电热电器制造有限公司 | Electromagnetic heating device and electromagnetic oven with same |
| CN206596256U (en) * | 2017-03-29 | 2017-10-27 | 佛山市顺德区美的电热电器制造有限公司 | Electromagnetic heating system and its heating control apparatus |
-
2018
- 2018-08-07 CN CN201810892151.0A patent/CN110811312B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106137072A (en) * | 2015-04-08 | 2016-11-23 | 夏宜智 | Commercial ultrasound ripple washes dish dish-washing machine |
| CN106961229A (en) * | 2017-04-06 | 2017-07-18 | 深圳拓邦股份有限公司 | A kind of self adaptation washing facility numerical control supersonic driver |
Also Published As
| Publication number | Publication date |
|---|---|
| CN110811312A (en) | 2020-02-21 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP4815499B2 (en) | Non-contact power transmission circuit | |
| EP1893002B1 (en) | Induction heating apparatus | |
| CN102186271B (en) | Method and induction heating device for determining a temperature of the base of a cooking vessel | |
| US20150250027A1 (en) | Induction heating cooker | |
| CN107155230B (en) | Electromagnetic heating cooking device, heating control circuit thereof and low-power heating control method | |
| JP6390808B1 (en) | Non-contact power feeding device | |
| EP3598850B1 (en) | Induction heating device performing container sensing function | |
| WO2020029695A1 (en) | Cooking appliance and ultrasonic oscillator drive control method and apparatus | |
| CN110811312B (en) | Cooking appliance and control device and control method thereof | |
| CN110801145A (en) | Control method and system of cooking device and cooking device | |
| CA3066024A1 (en) | Wireless power supply system for cooking appliance and cooking appliance | |
| JP2008119417A (en) | Induction heating rice cooker | |
| JP4706307B2 (en) | Induction heating device | |
| JP5979386B2 (en) | Induction heating cooker | |
| CN111227636B (en) | Cooking appliance and drive control method and device of ultrasonic vibrator | |
| CN111227635A (en) | Cooking appliance and drive control method and device of ultrasonic vibrator | |
| CN110811317B (en) | Cooking appliance and control device and control method thereof | |
| US11337279B2 (en) | Method for sensing container using resonant current | |
| JP2010182561A (en) | Induction heating cooking device | |
| CN114688952B (en) | Electromagnetic heating equipment, pot deviation detection method thereof and heating control system | |
| CN112714514B (en) | Electromagnetic heating equipment and heating control system and method thereof | |
| CN110393425B (en) | Electromagnetic cooking appliance and drive control method and device of IGBT (insulated Gate Bipolar transistor) tube thereof | |
| CN112714518B (en) | Electromagnetic heating equipment, control method and device thereof and storage medium | |
| CN112714513B (en) | Electromagnetic heating cooking utensil, temperature measuring method thereof and computer readable storage medium | |
| US20240055899A1 (en) | Wireless power transfer |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |