CN-122002655-A - Electromagnetic cooking utensil and heating method thereof

CN122002655ACN 122002655 ACN122002655 ACN 122002655ACN-122002655-A

Abstract

The application discloses an electromagnetic cooking appliance and a heating method thereof, and belongs to the technical field of electromagnetic heating, wherein a heating control circuit is arranged in the electromagnetic cooking appliance, the heating control circuit comprises an alternating current power supply, a zero crossing detection unit, a driving unit and a transistor which are electrically connected, the zero crossing detection unit is used for detecting a voltage zero point of the alternating current power supply, the driving unit is used for sending a driving signal to the transistor, when the electromagnetic cooking appliance is switched from a non-power interval to a power interval, a certain time is waited after the voltage zero point is detected, the driving unit is enabled to send a first driving signal to the transistor in a T1 time period after the waiting is finished, the first driving signal is enabled to continuously act on a T2 time period after the next voltage zero point, and a second driving signal is sent to the transistor in a T3 time period after the next voltage zero point, wherein the pulse width of the first driving signal is smaller than the pulse width of the second driving signal, and the pulse width of the second driving signal is gradually increased to be kept unchanged.

Inventors

WANG XUNING
LI XINXIANG
CUI WEIMIN
ZHANG LONG

Assignees

杭州九阳小家电有限公司

Dates

Publication Date: 20260508
Application Date: 20241029

Claims (10)

1. The heating method of the electromagnetic cooking appliance is characterized in that the heating control circuit comprises an alternating current power supply, a zero crossing detection unit, a driving unit and a transistor which are electrically connected, wherein the zero crossing detection unit is used for detecting the voltage zero point of the alternating current power supply, the driving unit is used for sending a driving signal to the transistor, When the electromagnetic cooking utensil is switched from a non-power interval to a power interval, waiting for a certain time after detecting a voltage zero point, enabling the driving unit to send a first driving signal to the transistor in a T1 time period after finishing waiting, enabling the first driving signal to continuously act on a T2 time period after the next voltage zero point, and sending a second driving signal to the transistor in a T3 time period after the next voltage zero point; the pulse width of the first driving signal is smaller than that of the second driving signal, and the pulse width of the second driving signal is gradually increased to be kept unchanged.
2. The heating method of an electromagnetic cooking device according to claim 1, wherein the T1 period is at least 4 times the T2 period.
3. The heating method of an electromagnetic cooking device according to claim 1, wherein the T2 period is less than 1/8 times the corresponding voltage period of the ac power source.
4. The heating method of an electromagnetic cooking device according to claim 1, wherein the pulse width of the first driving signal is equal and remains constant during both the T1 period and the T2 period.
5. The heating method of an electromagnetic cooking device according to claim 1, wherein a pulse width of the first driving signal is kept constant in both the T1 period and the T2 period, and the pulse width in the T2 period is smaller than the pulse width in the T1 period.
6. The heating method of an electromagnetic cooking device according to claim 1, wherein the pulse width of the first driving signal is maintained constant during the T1 period and gradually decreases during the T2 period.
7. The heating method of an electromagnetic cooking device according to claim 1, wherein the driving unit pauses transmission of the driving signal to the transistor before a T1 period when the electromagnetic cooking device is in a non-power section.
8. The heating method of an electromagnetic cooking device according to claim 1, wherein the pulse width of the second driving signal is finely adjusted according to the target heating power of the electromagnetic cooking device after the pulse width of the second driving signal is kept unchanged.
9. The heating method of an electromagnetic cooking device according to claim 1, wherein the transistor is an IGBT, the first driving signal and the second driving signal are pulse signals, and rising edges of the pulse signals are from 9V to 18V.
10. An electromagnetic cooking appliance, characterized by comprising a housing, a coil disk, and a heating control circuit applying a heating method of an electromagnetic cooking appliance according to any one of claims 1-9.

Description

Electromagnetic cooking utensil and heating method thereof Technical Field The application belongs to the technical field of electromagnetic heating, and particularly relates to an electromagnetic cooking utensil and a heating method thereof. Background Currently, most cooking appliances such as induction cookers and the like adopting electromagnetic heating work by adopting a resonance circuit of a single transistor, and a parallel resonance mode is generally adopted. At the start-up of the transistor, there are the following problems: 1) When a transistor is started by heating, a certain cooking appliance is directly started with certain power, at the moment, the instantaneous current is high at the moment of switching on the transistor due to the fact that the bus energy of the transistor is high, the current peak value limit of the transistor is easily exceeded, the transistor is damaged, meanwhile, the cooking appliance is at risk of a frying machine, and the starting noise of the cooking appliance is too large due to the instantaneous abrupt change of the current, so that the product experience of a user is affected; 2) Part of the cooking appliances adopts a soft start mode, the pulse width of a driving signal is gradually increased before the zero crossing point of the voltage until the pulse width is increased to the width corresponding to the target heating power after the zero crossing point, in the mode, the transistor is turned on for a short time before the zero crossing point of the voltage, and the transistor is turned on for a short time, but the problem of high current at the moment of conduction still exists due to higher accumulating capacity on a bus of the transistor; 3) Some cooking appliances start the transistor in a continuous high-frequency micro-conduction mode before a non-power stage, namely a zero crossing point, and adjust the pulse width to the width corresponding to the target heating power when the cooking appliance enters the power stage, namely the zero crossing point. The method can release bus voltage of the transistor to a certain extent, bus energy is consumed, so that the transistor is prevented from being started up in an instantaneous current, on one hand, the transistor is in a high-loss state of being turned on-off for a long time, the service life of the transistor is affected, meanwhile, the transistor is seriously heated and has higher temperature rise, on the other hand, the zero crossing detection can cause left-right offset between a detected zero point and an actual zero point when different mains voltages are detected, the offset zero point can cause the bus to still have high voltage when the transistor is actually conducted, the bus voltage is affected, the consumption result of bus energy is not ideal, in this way, the instantaneous current is still high when the transistor is started up, the transistor is started up with target heating power after the detected zero point, namely, the transistor is started up before the actual zero point, even if high-frequency micro-conduction is performed before the detected zero point, the actual zero point is shifted to the right, the high-frequency micro-conduction cannot be continued to the actual zero point, the bus energy consumption is not ideal, and the transistor is not started up in an instantaneous cooking current is also caused, and the transistor is in an instantaneous cooking apparatus is in danger of being caused. Disclosure of Invention The application provides an electromagnetic cooking appliance and a heating method thereof, which aim to solve at least one of the technical problems. The technical scheme adopted by the application is as follows: A heating method of an electromagnetic cooking appliance comprises the steps that when the electromagnetic cooking appliance is switched from a powerless interval to a power-on interval, a certain time is waited after the voltage zero is detected, the driving unit sends a first driving signal to the transistor in a T1 time period after the waiting is finished, the first driving signal is enabled to continuously act on a T2 time period after the next voltage zero, and a second driving signal is sent to the transistor in a T3 time period after the next voltage zero, wherein the pulse width of the first driving signal is smaller than that of the second driving signal, and the pulse width of the second driving signal is gradually increased to be unchanged. In one possible implementation of the present application, the T1 period is at least 4 times the T2 period. In one possible implementation of the present application, the T2 period is less than 1/8 times the corresponding voltage period of the ac power source. In one possible implementation of the present application, the pulse width of the first driving signal is equal and remains unchanged in the T1 period and the T2 period. In one possible implementation of the present application, the pulse width of the fi