KR100246426B1 - Switching drive circuit of induction heating cooker for magnetic and non-magnetic loads - Google Patents

Abstract

The present invention relates to a switching drive circuit of a magnetic and nonmagnetic induction cooker, which is conventionally expensive due to the high cost of a resonant capacitor, and also has a problem in that excessive voltage of thousands of volts is applied to a capacitor, which may cause noise in the operation of a peripheral circuit. there was. Accordingly, the present invention provides a timer for generating a pulse having a predetermined width; A dead time adjusting unit which receives the pulse signal of the timer and prevents simultaneous switching on and off of the switching element; An oscillator for receiving a signal of the dead time controller and oscillating a driving waveform accordingly; A signal selector which receives a signal of the oscillator and selects it by a control signal; It is composed of a switching driver for supplying the drive signal selected by the signal selector, and the magnetic and non-magnetic devices are designed to obtain a large output by using a high-pressure load selection capacitor used according to a magnetic load or a nonmagnetic load as a general-purpose filter capacitor. There is an effect that can implement a sex induction heating cooker.

Description

Switching drive circuit of magnetic and nonmagnetic induction cooker

The present invention relates to a switch driving circuit of a combined magnetic and nonmagnetic induction cooker, and in particular, a switch of a magnetic and nonmagnetic combined induction cooker to obtain a large output by using a high-pressure load selection capacitor as a general-purpose filter capacitor. It relates to a driving circuit.

Figure 1 is a circuit diagram showing the configuration of a conventional magnetic and nonmagnetic induction heating cooker, as shown in the rectifier 10 for rectifying the AC input power source; A filter unit 11 for receiving a signal from the rectifier 10 and filtering the filtered signal to improve the power factor; First and second switching elements S1 and S2 for switching a predetermined operation of the circuit; The resonant tank part 12 performs a predetermined resonant operation by the switching operation of the first and second switching elements S1 and S2.

The resonant tank part 12 connects the first and second capacitors Cr21 and Cr22 in series, and sequentially connects the working coil Lr and the third capacitor Cr1 to the connection points in series. The relay Ry is connected between the intermediate tap of the working coil Lr and the connection points of the first and second capacitors Cr21 and Cr22, and the operation of the conventional apparatus thus constructed will be described.

First, in the case of non-magnetic load, when the second switching device S2 is turned off and the first switching device S1 is turned on, the AC power AC is rectified by the rectifier 10 and filtered by the filter 11. It is applied to the resonant tank part 12 to start resonance and the current of the working coil Lr rises.

Here, the relay Ry of the resonant tank part 12 is turned on to form a resonant tank with the first coil Lr1 and the first and second capacitors Cr21 and Cr22 to operate as a half bridge.

At this time, when the first switching device S1 is turned off before the resonant half cycle of the resonance tank 12 passes, the capacitor Ca1 of the first switching device S1 and the capacitor of the second switching device S2 are turned off. (Ca2) is a secondary resonance with the resonant tank 12, the voltage charged in the capacitor (Ca2) of the second switching device (S2) drops to zero, while the capacitor (Ca1) of the first switching device (S1) The voltage applied to) increases from zero to the input voltage level.

Thereafter, the diode D connected in anti-parallel to the second switching element S2 is conducted, and a zero voltage is applied to the resonance tank 12.

Then, resonance continues by the voltage charged in the resonant capacitor Cr1 of the resonant tank part 12, and at this time, the second switching element S2 is turned on under the condition of zero voltage.

The resonant current drops to zero due to the continuous resonance and this time resonates in the opposite direction, thereby increasing the resonant current.

Here, when the second switching element S2 is turned off before the resonant half period passes, the capacitors Ca1 and Ca2 of the first and second switching elements S1 and S2 are assisted with the resonance tank 12. Resonance causes the voltage applied to the capacitor Ca1 of the first switching element S1 to fall to zero at the input voltage level and the voltage applied to the capacitor Ca2 of the second switching element S2 is zero to the input voltage. Rise to the level.

Thereafter, a diode D connected in parallel with the first switching element S1 is conducted, and an input voltage is applied to the resonance tank 12.

Accordingly, the resonance tank unit 12 continues to generate resonance. At this time, when the first switching device S1 is turned on under the condition of zero voltage, if the resonance current drops to zero by the continuous resonance, one cycle of operation is completed. The same operation is repeated over and over.

That is, the load is heated by the eddy current generated in the load by the current induced in the above manner.

In addition, the magnetic load operation is the same as the above, except that the resonant tank part is made to operate as a half bridge by the working coil Lr1 and the first and second capacitors Cr21 and Cr22 when the relay Ry is turned off. Is different.

However, the conventional apparatus operating as described above has a problem in that the resonant capacitor is expensive and inexpensive, and excessive voltage of several thousand volts is applied to the capacitor, thereby causing noise in peripheral circuit operation.

Accordingly, the present invention devised in view of the above problems provides a switch driving circuit of a magnetic and nonmagnetic induction heating cooker which can obtain a large output by using a high-pressure load selection capacitor as a general-purpose filter capacitor. There is this.

1 is a circuit diagram showing the configuration of a conventional magnetic and nonmagnetic induction heating cooker.

Figure 2 is a circuit diagram showing the configuration of the switching drive circuit of the present invention magnetic and nonmagnetic induction cooker.

Figure 3 is a circuit diagram showing the configuration of the magnetic and non-magnetic induction cooker to which the present invention is applied.

FIG. 4 is a mode division diagram in FIG. 3. FIG.

Fig. 5 is a waveform diagram of each part in Fig. 2.

***** Description of the symbols for the main parts of the drawings *****

20: timer 21: dead time control unit

22: oscillation output section 23: control section

24: Signal selector 25: Switching selector

The above object is a timer for generating a pulse having a predetermined width; A dead time adjusting unit which receives the pulse signal of the timer and prevents simultaneous switching on and off of the switching element; An oscillator for receiving a signal of the dead time controller and oscillating a driving waveform accordingly; A signal selector which receives a signal of the oscillator and selects it by a control signal; This is achieved by configuring a switching driver for supplying a drive signal selected by the signal selector, which will be described with reference to the accompanying drawings.

Figure 2 is a circuit diagram showing an embodiment of the magnetic and nonmagnetic induction heating cooker switch driving circuit of the present invention, and a timer 20 for generating a pulse having a predetermined width as shown therein; A dead time adjusting unit 21 which receives the pulse signal of the timer 20 and prevents simultaneous switching on / off during the switching operation of the switching element; An oscillation output unit 22 for receiving a signal from the dead time adjusting unit 21 and oscillating a driving waveform accordingly; A signal selector 24 which receives the signal of the oscillation output unit 22 and selects it by a control signal of the controller 23; The switching driver 25 supplies a drive signal selected by the signal selector 24.

)으로부터 신호를 입력받아 이를 데드타임조절부(21)의 신호와 노아 연산하는 제2 노아게이트(NOR2)로 구성한다.The oscillation output unit 22 includes a flip-flop (T-ff) for receiving a signal from the dead time control unit 21 and toggling it; A first NOR gate NOR1 that receives a signal from the positive output terminal Q of the tip flip-flop T-ff and performs a NOR operation on the signal of the dead time controller 21; Negative output terminal of the flip-flop (T-ff)

A second NOR gate NOR2 configured to receive a signal from the signal and output the signal from the dead time controller 21 and NOR it.

The signal selector 24 receives a signal from the first NOR gate NOR1 of the oscillation output unit 22 and transmits the signal by the control signal inverted by the inverter IN1. ; The second transmission gate G2 receives a signal from the second NOR gate NOR2 of the oscillation output unit 22 and transmits the signal by the control signal inverted by the inverter IN2.

Figure 3 is a circuit diagram showing the configuration of an embodiment of a magnetic and nonmagnetic induction heating cooker to which the present invention is applied, as shown in the rectifier 10 for rectifying the AC input power (AC); A filter unit 30 for receiving a signal from the rectifier 10 and filtering the filtered signal to improve power factor; First to fourth switching elements S1 to S4 that receive the switching signals and switch accordingly; A resonant tank part 31 which resonates by the switching operation of the first to fourth switching elements S1 to S4, and the filter part 30 includes a capacitor Cf1 connected in series to the coil Lf, The resonant tank part 31 connects the second coil Lr2 and the capacitor Cr1 connected in series with the first coil Lr1, and connects the relay Ry to the connection point thereof. Connect to configure.

Referring to the operation of the embodiment of the present invention configured as described above are as follows.

First, the operation of the magnetic and nonmagnetic induction cooker to which the present invention is applied is the same as in the related art, except that the magnetic load relay Ry is turned on and the third and fourth switching are turned on as shown in the mode classification diagram of the induction cooker of FIG. The first and second switching elements S1 and S2 are alternately driven so that the elements S3 and S4 are turned off to form a resonant tank with the first coil Lr1 and the capacitor Cr1. The relay Ry is turned off and the first and fourth switching elements S1, S4, and the second and the second coils Lr1, Lr2 and the capacitor Cr1 form a resonant tank. The alternating operation of the third switching elements S2 and S3 in pairs is different.

The operation of the switching driving circuit of the magnetic and nonmagnetic induction heating cooker of the present invention for controlling the operation of the first to fourth switching elements S4 as described above will be described with reference to the timing diagram of FIG.

First, when the timer 20 generates a pulse having a predetermined pulse width as shown in (a) of FIG. 5, the dead time controller 21 prevents simultaneous switching on and off during the alternating operations of the switching elements S1 to S4. The dead time is set to output a signal as shown in FIG.

At this time, the tip flip-flop (T-ff) of the oscillation output unit 22 is applied to the tee input terminal (T) by a signal as shown in Figure 5 (b) of the dead time adjusting unit 21 to toggle the output do.

)는 도5의 (d)와 같은 신호를 출력한다.Here, the tip flip-flop T-ff outputs a signal as shown in (c) of FIG. 5 when the pulse input to the tee input terminal T has a rising edge. Negative output terminal of flip-flop (T-ff)

) Outputs a signal as shown in FIG.

)로부터 출력된 도5의 (d)와 같은 신호와 노아연산하여 도5의 (e)와 같은 신호를 출력한다.Accordingly, the first NOR gate NOR1 of the oscillation output unit 22 receives a signal as shown in FIG. 5B of the dead time adjusting unit 21 and receives the signal of the tip flip-flop T-ff. The signal output as shown in Fig. 5 (f) is output by outputting the signal as shown in Fig. 5 (c) output from the output terminal Q, and the oscillation output section 22 is similar to the second NOR gate NOR2. Is a negative output terminal of the tip-flop (T-ff) receives a signal as shown in (b) of FIG.

The signal shown in (e) of FIG. 5 is output by performing NOA operation on the signal shown in (d) of FIG.

Herein, if the container to be heated is in the magnetic mode, the controller 23 determines that the first and second transfer gates G1 and G2 of the signal selector 24 are turned off so that the first and second switching devices are turned off. The control is performed so as to alternate operation only with (S1) and (S2).

Accordingly, the relay Ry of the resonant tank part 31 is turned on, and the resonant tank is formed and driven by the capacitor Cr1 and the first coil Lr1 of the resonant tank part 31.

If the container to be heated is in the non-magnetic mode, the controller 23 determines this and controls the first and second transfer gates G1 and G2 of the signal selection unit 24 to be turned on to control the first and fourth parts. The switching elements S1 and S4 and the second and third switching elements S2 and S3 are bundled in a pair and controlled to be alternately operated.

Accordingly, the relay Ry of the resonant tank unit 31 is turned off, and the first and second coils Lr1 and Lr2 and the capacitor Cr1 form and drive the resonant tank.

As described in detail above, the present invention can implement a magnetic and nonmagnetic induction heating cooker designed to obtain a large output by using a high-pressure load selection capacitor used according to a magnetic load or a nonmagnetic load as a general-purpose filter capacitor. It works.

Claims (4)

A timer for generating a pulse having a predetermined width; A dead time adjusting unit which receives the pulse signal of the timer and prevents simultaneous switching on and off of the switching element; An oscillation output unit which receives a signal of the dead time controller and oscillates a driving waveform accordingly; A signal selector which receives a signal of the oscillation output unit and selects the signal by a control signal of a controller; And a switching driver for supplying a drive signal selected by the signal selection unit. 2. The apparatus of claim 1, further comprising: a flip-flop that receives the signal of the dead time control unit and toggles it; A first noble gate which receives a signal from the positive output terminal of the tip flip-flop and compiles it with a signal of a dead time controller; The switching drive circuit of the magnetic and non-magnetic induction cooker, characterized in that the input signal received from the output terminal of the flip-flop is composed of a second noah gate for performing a Noah operation with the signal of the dead time control unit. 2. The apparatus of claim 1, wherein the signal selector comprises: a first transmission gate configured to receive a signal from the first NOA gate of the oscillation output unit and transmit the signal by a control signal inverted by the first inverter; And a second transmission gate configured to receive a signal from the second NOA gate of the oscillation output unit and transmit the signal by the control signal inverted by the second inverter. The control unit of claim 1, wherein the control unit determines that the container to be heated is in the magnetic mode, and controls the first and second transfer gates of the signal selection unit to be turned off to control the first and second switching elements to alternately operate. If the container is in the non-magnetic mode, the controller determines this and controls to turn on the first and second transfer gates of the signal selection unit so that the first and fourth switching elements and the second and third switching elements are alternately operated. Switching drive circuit of the magnetic and non-magnetic induction cooker, characterized in that the control to make.

Images