CN214069551U - Electric heating equipment for kitchen and control device thereof - Google Patents

Abstract

The application relates to an electric heating equipment for kitchen and controlling means thereof includes: the first switch circuit and the main control circuit; the first switch circuit is connected in series in a filter capacitor branch of the LC filter circuit; the control of the main control circuit is connected with the control end of the first switch circuit, when the kitchen electric heating equipment is in a low-power working mode and is in an intermittent working process, the main control circuit outputs a control signal to control the first switch circuit to be switched off after detecting that the input voltage of the alternating current power grid reaches a valley point, so that the filter capacitor of the LC filter circuit does not store energy in the intermittent working process. This application can avoid switching on in the twinkling of an eye at IGBT, because the electric capacity route produces peak current, leads to unnecessary electric energy loss, protects IGBT not damaged simultaneously, improves the fail safe nature of electromagnetism stove work.

Description

Electric heating equipment for kitchen and control device thereof

Technical Field

The application relates to kitchen electric heating equipment and a control device thereof, and belongs to the technical field of automatic control.

Background

At present, heating equipment for kitchens mainly comprises two modes of natural gas heating and electric heating, wherein an induction cooker is used as a mainstream, the induction cooker is also called an induction cooker, in the use occasion of the induction cooker, the phenomenon that the heating power is adjusted at any time is very common is also the most basic requirement, and a control circuit can adjust the heating power of the induction cooker by changing the switching frequency of an IGBT (insulated gate bipolar translator) in a power-on loop or changing the peak current of a heating wire coil of the induction cooker. Under the condition of high-power heating, the induction cooker is in a continuous uninterrupted working state, but the low-power output of the induction cooker can be met only by an intermittent working state.

Because the power grid voltage input end of the induction cooker is provided with the LC filter circuit for filtering, the induction cooker can pause for a plurality of periods and does not work in the intermittent working process, the filter capacitor in the LC filter circuit is fully charged and is released everywhere during the period, the voltage reaches the peak value of the power grid voltage input, and when the induction cooker works in the next electrifying mode, the filter capacitor can form a rapid discharging path through the IGBT.

The discharge path of the filter capacitor generates a spike voltage and produces a spiking sound. And because the current in the discharging path does not output external power, a large impact current can be generated inside the IGBT of the discharging path, so that the instantaneous loss of the IGBT is extremely large, the IGBT generates heat, and the IGBT can be burnt in a short time in a serious condition.

SUMMERY OF THE UTILITY MODEL

The application provides a controlling means of electric heating equipment is used in kitchen can solve among the prior art kitchen and use electric heating equipment under intermittent type mode, and filter capacitor among the controlling means leads to producing the instantaneous current sudden change because of the nowhere release of energy storage to produce the harsh sound, and burn out the problem of IGBT because of great impulse current.

In order to solve the technical problem, the application provides the following technical scheme:

in a first aspect of the embodiments of the present application, there is provided a control device for an electric cooking heating apparatus, including:

the first switch circuit and the main control circuit;

the first switch circuit is connected in series in a filter capacitor branch of an LC filter circuit, and the LC filter circuit is arranged at the voltage input end of an alternating current power grid of the kitchen electric heating equipment;

the first control output end of the main control circuit is connected with the control end of the first switch circuit, and when the kitchen electric heating equipment is in an intermittent working process, the main control circuit outputs a control signal to control the first switch circuit to be switched off after detecting that the input voltage of an alternating current power grid reaches a valley point, so that the filter capacitor of the LC filter circuit does not store energy in the intermittent working process;

and an AC voltage detection port of the main control circuit is connected with an AC power grid voltage input end and is used for detecting the AC power grid input voltage.

A second aspect of the embodiments of the present application provides an electric cooking appliance including the control device according to the first aspect of the embodiments of the present application.

The beneficial effect of this application lies in: this application is through the first switch circuit of series connection in LC filter circuit's filter capacitor branch road, can control filter capacitor's discharge circuit disconnection when the intermittent type work mode of electromagnetism stove to make filter capacitor not accumulate under the intermittent type work mode, when preventing that the intermittent type work mode from ending, IGBT switches on in the twinkling of an eye, produces peak current because the electric capacity route, leads to unnecessary electric energy loss, protects IGBT not damaged simultaneously, improves the fail safe nature of electromagnetism stove work.

When the output power of the induction cooker needs to be reduced, the condition that the resonant waveform does not cross zero due to insufficient energy is avoided by adjusting the interval time of the intermittent working mode, and the energy loss when the IGBT is switched on next time is reduced.

Because the interval time of the intermittent working mode is accurate and adjustable, the minimum time interval can reach one half of the period of a power grid (namely, the minimum time interval can reach 0.01 second under 50Hz power frequency), the electromagnetic oven can be controlled by the first driving module to realize the output of any power, and noise can not occur.

The foregoing description is only an overview of the technical solutions of the present application, and in order to make the technical solutions of the present application more clear and clear, and to implement the technical solutions according to the content of the description, the following detailed description is made with reference to the preferred embodiments of the present application and the accompanying drawings.

Drawings

Fig. 1 is a schematic circuit diagram of a control device of an electric cooking heater according to an embodiment of the present application.

FIG. 2 is a schematic circuit diagram of a control device according to an embodiment of the present application;

fig. 3 is a waveform diagram of a portion of the model of fig. 2.

Detailed Description

The following detailed description of embodiments of the present application will be described in conjunction with the accompanying drawings and examples. The following examples are intended to illustrate the present application but are not intended to limit the scope of the present application.

Fig. 1 is a schematic circuit diagram of a control device of an electric cooking appliance according to an embodiment of the present invention, which may be an induction cooker, and the control device of the present invention will be described below by taking the induction cooker as an example.

As shown in fig. 1 and 2, the control device according to the embodiment of the present application includes: the electromagnetic oven comprises a main control circuit and an IGBT switch circuit, wherein the IGBT switch circuit is connected in series in a power supply loop of the electromagnetic oven, and the main control circuit is used for controlling the on-off of the IGBT switch circuit according to the magnitude of current flowing through a heating wire coil L2 and the resonance condition of the heating wire coil L2 and a capacitor C3.

When the electromagnetic oven works, the main control circuit controls the IGBT switching circuit to be started, the heating wire coil L2 of the electromagnetic oven starts to store energy, the current flowing through the heating wire coil L2 is continuously increased along with time, and when the main control circuit detects that the current flowing through the heating wire coil L2 reaches a preset current value, the IGBT switching circuit is controlled to be switched off.

A heating wire coil L2 of the induction cooker is an inductance element with high-frequency resonance, a capacitor C3 is connected in parallel with L2 to form an LC resonance circuit, and an alternating magnetic field is generated between the heating wire coil L2 and the capacitor C3 to heat a conductor by continuous charging and discharging. Along with the reduction of the resonance energy, when the main control circuit detects the zero crossing point of the resonance voltage, the output control signal controls the IGBT switching circuit to be opened, and the L2 is charged again to store energy.

When the induction cooker is in a high-power working mode, the IGBT switching circuit is continuously started, and the working cycle is uninterrupted; and under the low-power working mode, the IGBT switching circuit can be suspended for a plurality of working cycles and does not work, and the IGBT switching circuit is intermittently started by adopting an intermittent working mode.

Fig. 2 is a schematic circuit diagram of a control device according to an embodiment of the present application, and as shown in fig. 2, the main control circuit includes a current detection module, a voltage detection module, a second driving module, and a PWM control module. Wherein,

the current detection module is used for detecting the current flowing through the heating wire coil of the induction cooker and outputting a detection result to the PWM control module.

The control output end of the PWM control module is connected with the control end of the IGBT switch circuit through the second driving module, the PWM control module sends a control signal to the second driving module to drive the IGBT switch circuit to be started when the electromagnetic oven works, and when the current flowing through the heating wire coil L2 is detected to reach a preset value, the PWM control module outputs the control signal to the second driving module to drive the IGBT switch circuit to be turned off.

The voltage detection module is used for detecting the resonant voltage of the heating wire coil L2 and sending a detection result to the PWM control module, and the PWM control module outputs a PWM signal to the second driving module when receiving the resonant voltage zero crossing and the resonant energy is too low, so as to drive the IGBT switching circuit to be conducted again.

The IGBT switching tube Q1 is connected in series in a power supply loop of the induction cooker.

The IGBT switch tube of this embodiment is an N-connected IGBT, and certainly, a P-connected IGBT can be selected, and the specific type of the IGBT is not limited in this embodiment. In other embodiments, other types of transistors may be selected, as long as the corresponding functions are achieved.

Taking the IGBT with an N-channel as an example in this embodiment, the emitter collector of the IGBT switch is connected to one end of the current detection resistor R1, and the other end of the current detection resistor R1 is grounded. And the series connection point of the emission set of the IGBT switch tube and the resistor R1 is also connected with the input end of the current detection module, and the current detection module determines the current flowing through the heating wire coil L2 by detecting the voltage values at the two ends of the resistor R1.

The collector electrode of the IGBT switch tube is connected with a heating wire coil L2 of the induction cooker, the collector electrode of the IGBT switch tube is further connected with the input end of the voltage detection module, and the voltage detection module detects the voltage of the collector electrode of the IGBT switch tube Q1 to determine the resonant voltage of a resonant circuit formed by the heating wire coil L2 and the resonant capacitor C3.

And the driving signal output end of the second driving module is connected with the gate electrode of the IGBT switching tube Q1, and the second driving module outputs a driving signal to the gate electrode of the IGBT switching tube Q1 to control the on-off of the IGBT switching tube.

Further, the control device further comprises an MOS switch circuit, and the MOS switch circuit is connected in series in a capacitor branch of the LC filter circuit.

The LC filter circuit is arranged at the voltage input end of the power grid and used for filtering input voltage. LC filter circuit includes parallel connection's inductance L1 and electric capacity C2, an end connection network input voltage of inductance L1, inductance L1's the other end and heating drum L2 are established ties, inductance L1 and heating drum L2's series connection point is connected to electric capacity C2's one end, another termination MOS switch circuit of electric capacity C2.

The MOS switch circuit comprises a MOS switch tube Q2, wherein the input end of the MOS switch tube Q2 is connected with a capacitor C2, and the output end is grounded. Referring to fig. 2, the MOS switch Q2 is an N-type transistor connected to the MOS transistor, and has a grounded source and a grounded drain connected to the capacitor C2. Of course, a P-channel MOS transistor or other suitable switching transistor may also be used, and the embodiment of the present application is not limited herein.

In the embodiment, the induction cooker enters an intermittent mode at the valley bottom of the voltage of an alternating-current power grid, an IGBT is closed, and meanwhile, a main control circuit controls an MOS (metal oxide semiconductor) switching tube connected in series with a filter capacitor C3 to be turned off; and after the intermittent time set by the main control circuit is over, the IGBT is restarted at the valley bottom of the alternating current power grid, and when the intermittent mode is over and before the IGBT is started, the main control circuit controls the MOS switch tube connected with the filter capacitor C2 in series to be started in advance.

This application embodiment is in electromagnetism stove intermittent type working process, turn-off through control MOS switch tube Q2, cut off electric capacity C2's route, guarantee electric capacity C2 and do not store energy in electromagnetism stove intermittent type working process, thereby can guarantee when intermittent type mode ends, IGBT switch tube Q1 opens in the twinkling of an eye, because there is not energy storage on electric capacity C2, Q1's collecting electrode can not appear peak current because electric capacity C2's route, the protection IGBT is not damaged, can avoid unnecessary power loss simultaneously, and the efficiency is improved, safety and reliability.

Optionally, the main control circuit further includes a first driving module, a power adjusting module, and an AC detecting module.

The voltage detection port of the AC detection module is connected with the voltage input end of a power grid, the signal output end of the AC detection module is connected with the power regulation module, and the AC detection module is used for detecting the input voltage of the alternating current power grid and outputting the input voltage to the power regulation module.

The output end of the power adjusting module is connected with the PWM control module, and the power adjusting module is used for outputting a power adjusting signal to the PWM control module according to the detected power grid voltage.

The PWM control module is characterized in that a PWM signal output end of the PWM control module is connected with a first driving module, a signal output end of the first driving module is connected with a grid electrode of an MOS (metal oxide semiconductor) switching tube Q2, and the PWM control module outputs a PWM signal according to a power regulation signal to control the work of an MOS switching tube Q2.

Furthermore, the main control circuit further comprises a single chip microcomputer, a signal input end of the single chip microcomputer is connected with the human-computer interaction module, and a signal output end of the single chip microcomputer is connected with the power adjusting module.

The human-computer interaction module is used for inputting power demand signals (namely, signals with different power magnitudes) to the single chip microcomputer, the single chip microcomputer analyzes and processes the power demand signals and outputs a power regulation plan to the power regulation module, the power regulation module determines the switching frequency of Q1, the peak current of the heating wire coil and the output signal of the first driving module according to the power regulation plan and sends the output signal to the PWM control module, and the PWM control module outputs PWM signals to control Q1 and Q2 to work.

Under the intermittent working mode, the single chip microcomputer can give a plan at any interval of intermittent time, the minimum intermittent time can be one half of the period of an alternating current power grid (namely, under the power frequency of 50Hz, the minimum intermittent time can reach 0.01 second), and the output of any power is controlled under the condition, so that the effect of uniform heating under any power output is realized.

Furthermore, the main control circuit further comprises a protection module, a signal output end of the protection module is connected with the PWM control module, and the protection module is used for outputting a protection signal to the PWM control module to switch off the second switch circuit when detecting that the kitchen electric heating equipment is in an abnormal working state.

The method and the device can ensure that the heating wire coil can be fully charged in each rectified power grid period when the induction cooker is in a non-intermittent working mode, namely, the sufficient resonance energy is ensured, and each resonance can zero through; in the intermittent working mode, the single chip microcomputer can provide a plan at any interval of intermittent time, the minimum intermittent time can be one half of the period of an alternating current power grid (namely, the minimum intermittent time can reach 0.01 second under 50Hz power frequency), and the output of any power is controlled under the condition, so that the effect of uniform heating under any power output is realized.

The specific working process of the control device in the embodiment of the application is as follows:

a power demand signal is input to the single chip microcomputer through the man-machine interaction module, the single chip microcomputer gives a control plan to the PWM control module, and the PWM control module determines the switching frequency of the IGBT switching tube Q1, the peak current of the heating wire coil and an output signal of the first driving module.

When the electromagnetic oven needs high-power (for example, 900-2000W) output, the second driving module outputs a high-level signal to turn on the IGBT switch tube Q1, the output of the first driving module is always at a high level, and the MOS switch tube Q2 is kept continuously on, so that the capacitor C2 is ensured to normally work, and current starts to flow on the heating wire coil L2 and rises along with the increase of time. When the current detection module detects that the voltage of the collector electrode of the IGBT switching tube Q1 reaches a set value, namely the current flowing through the heating wire coil L2 reaches a preset current value, the PWM control module outputs a control signal to the second driving module to turn off the Q1. Because the current on the heating wire coil L2 can not suddenly change, the L2 and the C3 start to resonate, the resonant voltage is continuously reduced along with the reduction of the resonant energy, and when the Q1 is conducted next time, the voltage detection module needs to be ensured to detect the zero crossing of the resonant voltage at the collector terminal of the Q1.

When the system needs low-power (for example, 300-600W) output, according to the alternating current grid voltage detected by the AC detection module, the system enters an intermittent operation mode at the valley bottom of the alternating current grid voltage, the PWM control module outputs a PWM signal to the first driving module, and the driving Q2 is turned off when the voltage VIN on the capacitor C2 reaches the valley point, (wherein, the voltage VIN on the capacitor C2 is synchronous with the grid voltage AC), so as to ensure that the capacitor C2 does not store electricity in several periods when the Q1 stops operating, and the first driving module is turned on until the set delay time of the intermittent operation reaches and is at the valley bottom of the grid voltage signal, and the Q2 is turned on again; when the PWM control module receives the signal that Q2 is turned on, Q1 is controlled to be turned on. Fig. 3 is a signal waveform diagram in the intermittent operation mode according to the embodiment of the present application.

The first driving module can ensure that no energy is stored in the capacitor C2 even if the induction cooker does not work for several cycles in the intermittent working mode, so that when the Q1 is turned on again, no peak current occurs on the collector of the Q1 due to the capacitor path, and the EMI (electro-magnetic interference) characteristic of the control device is improved.

This application can realize that electromagnetism stove output power size is adjustable in succession, through establishing ties MOS switch circuit on filter capacitor C2 to set up power adjusting module and the work of first drive module control MOS switch circuit, make Q1 in the twinkling of an eye that switches on, the electric current can not be from zero sudden change to great value, has reduced the unnecessary loss, has improved the security performance of electromagnetism stove.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the utility model. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims (9)

1. A control device for an electric cooking heating apparatus, the control device comprising: the first switch circuit and the main control circuit;

the first switch circuit is connected in series in a filter capacitor branch of an LC filter circuit, and the LC filter circuit is arranged at the voltage input end of an alternating current power grid of the kitchen electric heating equipment;

the first control output end of the main control circuit is connected with the control end of the first switch circuit; and an AC voltage detection port of the main control circuit is connected with an AC power grid voltage input end.

2. The control device for a kitchen electric heating apparatus according to claim 1, further comprising:

a second switching circuit;

the second switching circuit is connected in series in a power supply loop of the electric kitchen heating equipment;

the second control output end of the main control circuit is connected with the control end of the second switch circuit;

and a current signal detection port of the main control circuit is connected with the signal output of the second switch circuit.

3. The control device of electric kitchen heating equipment according to claim 2, wherein the main control circuit comprises a first driving module, an AC detection module, a power regulation module and a PWM control module, a signal input end of the AC detection module is connected to a grid voltage signal, a signal output end of the AC detection module is connected to an input end of the power regulation module, an output end of the power regulation module is connected to the PWM control module, a PWM signal output end of the PWM control module is connected to the first driving module, and a signal output end of the first driving module is connected to a control end of the first switch circuit.

4. The control device of electric cooking heating equipment according to claim 3, wherein the main control circuit further comprises a current detection module, a voltage detection module and a second driving module, an input terminal of the current detection module is connected to an output terminal of the second switch circuit, an output terminal of the current detection module is connected to an input terminal of the PWM control module, an input terminal of the voltage detection module is connected to an input terminal of the second switch circuit, an output terminal of the voltage detection module is connected to an input terminal of the PWM control module, a PWM signal output terminal of the PWM control module is connected to an input terminal of the second driving module, and a driving signal output terminal of the second driving module is connected to the second switch circuit.

5. The control device of electric kitchen heating equipment as claimed in claim 4, wherein the main control circuit further comprises a single chip, a signal input end of the single chip is connected with the man-machine interaction module, and a signal output end of the single chip is connected with the power regulation module.

6. The control device of electric cooking heating equipment according to claim 5, wherein the main control circuit further comprises a protection module, and a signal output terminal of the protection module is connected to the PWM control module.

7. The control device of electric cooking heating equipment according to claim 3, wherein the first switch circuit is a MOS switch circuit, and comprises a MOS switch tube, the MOS switch tube is connected in series with the capacitor branch of the LC filter circuit, and the gate of the MOS switch tube is connected to the driving signal output end of the first driving module.

8. The control device of the electric cooking heating apparatus according to claim 4, wherein the second switching circuit is an IGBT switching circuit, and comprises an IGBT switching tube, and the IGBT switching tube is connected in series in a power supply loop of the electric cooking heating apparatus;

the gate electrode of the IGBT switching tube is connected with the driving signal output end of the second driving module;

the emitting set of the IGBT switch tube is connected with a current detection resistor R1, and the serial point of the emitting set of the IGBT switch tube and the current detection resistor R1 is connected with the input end of the current detection module;

and the collector electrode of the IGBT switch tube is connected with a heating wire coil of the kitchen electric heating equipment, and the collector electrode of the IGBT switch tube is connected with the input end of the voltage detection module.

9. An electric cooking heating appliance comprising a control device according to any one of claims 1 to 8.

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