JPS6044992A - Electromagnetic induction heater - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] +Effect j is about A can (, Hide J4 me heating '1♂ and 1 city', and furthermore Wl' IO small 1-Ji- is not jF'+1 sex day 1ii
The protection against i is set to 1 and the exposure resistance r′lf is odd or η・
An electromagnetic heating device that can suppress abnormal noises when the drive is stopped when the drive is stopped.
This is a proposal.

Electromagnetic rT)? '! There are known cooking appliances that completely heat up an iron pot using the ``l'' phenomenon. If a low 4-dimensional load is applied to the induction heating coil, use the Makoto coil:!-i1
Heavy-wave current If an excessive load is applied to the switching element YC of the inverter circuit due to the full-wave current, this element may be destroyed. For this reason, 41+1 protection circuits have been proposed. This element protects the inverter circuit when all unsuitable loads are detected by human gravity.
Although it is detected by stopping the drive, the detection of unsuitable load is performed at the maximum timing,
At this timing, the Kakeru 111IJ was launched.
, ffK, and F were large, which caused the inverter circuit's oscillation stop sound to startle the user. Then, in one station where an unsuitable load was detected, the input current was gradually reduced, and then the oscillation was stopped in such a way that the current occurred by 1J (stopped! 1 - Q) - 1υJ + 1 - 1 The overall purpose is to provide an electromagnetic heating device.

The following is a misrepresentation of the misfire j based on the diagram ifn vc showing its embodiment.0 Figure 1 is an electromagnetic heating device 1'□〕 for misfire 1.
It shows the impark circuit part of. The direct current obtained by the full-wave rectifier 2 connected to the four-phase frequency alternating current source 1 is to be supplied to the single-ended bush-pull type inverter circuit 5 via the choke coil 3 and smoothing capacitor 4. There is. The inverter circuit 5 includes a self-column resonant circuit including an induction heating coil 5a and a resonant capacitor 5b, and is connected in parallel with the white column mutual circuit switching transistor 5c and in antiparallel with the flywheel diode 5d. . The collector of the switching transistor 5c is connected to the connection point between the choke coil 4 and the induction heating coil 5a, and the emitter is connected to the collector of another switching transistor 5e. The emitter of the transistor 5e is connected to the negative electrode side of the Nitwave rectifier 2, and a diode 5f is connected in parallel to the transistor 5e. and transistor 5c.

Drive circuits 6 and 7 are connected to the base emitters 5e, respectively.

This inverter circuit receives a Hals signal to turn on the transistor 5e from a control circuit (to be described later) via the drive circuit 7, and this causes a current to flow in the coil 5a in the direction of the arrow, and the capacitor 5b is charged by this current. . Next, after turning off the transistor 5e, a pulse signal to turn on the transistor 5c is not given from a control circuit (not shown) via the drive circuit 6, thereby discharging the photoelectric charge of the capacitor 5b, and causing the coil 5a and the transistor A current is passed through 5c in the opposite direction to the arrow mark. In this way, the transistor 5e.

Coil 5 by alternately turning on 5c at high frequency.
A has a four-frequency torrent current flowing through the pot 8 placed on the coil 5a.
Furthermore, it becomes possible to heat the food inside the candy 8. The induction heating coil 5a and the capacitor 5b are connected in series to each other, and a current flow detector 9 detects the current, and a diode 5f is connected between the cathode of the diode 5f and the connection point between the cathode and the capacitor 5b. A friend current device 10 is installed to detect the flowing current.

The second diagonal diagram shows a control circuit for the transistor 5e, which is a main part of the inventive device. The basic pulse signal A shown in FIG.
By applying the voltage to the base of the transistor 11 to turn it on and off, and charging and discharging the capacitor 12 connected in parallel to it, the voltage is applied to the collector of the transistor 11 as shown in FIG. 3 (b).
The sawtooth reference signal B shown in FIG.
It is applied to the + input terminal of 3. The basic pulse signal A is also given to the - manual sieve of the comparator 14, which has the potential of the + input terminal fixed, and is inverted and amplified thereby, and the outputs of both comparator are combined into the manual sieve of the 3-input AND gate 15 (Fig. 3). (c)] Toshishita.

The basic pulse 1 signal A turns on the transistor 5c while it is at a high level, and the comparator 1 which inverts this turns on the transistor 5c.
4 while the output A can be high level, the transistor 5e
is turned on to prevent both from being turned on at the same time.

The terminal voltage E of the smoothing converter 4 shown in FIG. 4 (a) is detected in the input power setting signal D shown in FIG. This is a signal that is created, and the human power is determined according to the tutee ratio of this setting signal D.

In other words, when the setting signal is always at a high level, the input force is 100% of the rated value, and for example, when the setting signal D has a tute ratio of 1/10 (100 milliseconds high, 900 milliseconds low), the input power is It becomes 10% of the rating.

This input power setting signal D is input to the AND gate 15 and is applied to the flip-flop 16 via a delay circuit, an inverter, and a differentiating circuit. There is no way to send this by applying a low trigger to the set terminal S of 16. Similarly, there is no need to apply this to the set terminal S of the flip flop 17 to set it.

The terminal voltage E of the smoothing capacitor 4 is determined by the comparator 18.1.
There are 9 + input terminals. The output of the current transformer 9 [Fig. 5 (a), Fig. 6 (a)] and the output of the current transformer 10 are rectified and given to one input terminal of the cosciparators 18 and 19. Here, it is compared with the voltage E, and if the -power is around the + input E, the outputs of the comparators 18 and 19 fall to low level, and this guy! j, F CFigure 5 (
6(b)], the resent ☆111j R of the flip 7rj knob 16 is low-triggered to turn this force into a reset state I-. '11 (pressure iJ) which rectified the current transformer 9 output
0 fritsuf 70 tsubutu 1 given to the talented comparator 13's single-handed ☆ 111j child given by Contessa 21
6 outputs vs. 1) NP transistor based on 200! When the output of the flip-flop 16 is low, the run raster 20 is all turned on, and when the 7 rib front 16 is reset fLfc, the transistor 204 is turned on. ,
VC is 1~ so that the single power G of the comparator 13 [FIG. 6 (c)] is set to +V'c.

The timer IC (555
u) The pulse signal H [fifth
Figure (c)]. This signal becomes low trigger (ICC Figure 5) which falls to low level at the timing when the signal goes high by an inverter etc.
Reset terminal RK of lip 70 knob 17 is given 7
The Q output of the lip flop 17 (Fig. 5 tj-) is A
Nl,) is one input of the gate 15, AND (1) The output is not given to the drive circuit 7.
, without K so that the transistor 5e is turned on when this is at a high level.

As described above, structure 1j: Also the misfire 11' device 1-t
Theory about the 1101th work (J. Negative and Ij that are suitable without selection
(age 18) is applied to the dielectric 4p heating coil 8, the terminal voltage E of the smoothing capacitor 4 is changed to the current transformer 9.1.0.
11j force does not exceed comparators 18 and 19.
The output of i! is high level. ff 4 protection, 7 ribs 70
The transistor 20 is turned on, and the current is changed as shown in the left part of FIG. Pulse r of the output or input current of the device 9
1g) following 1. Showing a scissors meeting. As shown by the broken line in FIG. 3(b), this causes the reference signal B
The output is kept at low level for a period of time when the ratio is 1 (G) 13. Therefore, as shown in FIG. is large (small) culm (
Fire), so the input power is low. Therefore, while the human power 'MIL force setting Id is at the 7 level, it is applied to the drive circuit 7 and the transistor 5e to 11'Ir is
Turns on continuously. Note that one transistor 5c is turned on at the timing when the pulse 4 (4-'p3A is at the -I level).

So it's not 11.・When the negative rdi of the 4-voltage is kicked off, the output of 10 is applied to the current transformer 9V.
Also, the output of pin 19 becomes low level, and as shown in Figures 5 (b) and 6 (b) VC shows 7J-, the reset of 7 lip 70 knob 16 is reset by human power F or low level, and this force resets everything. .So, the transistor 20 turns off.
K, J:p voltage II-"Vc is applied to the capacitor 21, and its terminal voltage rises as shown in FIG. 6 (c).

This heavy pressure G is applied to the comparator 13 as a result G)
B] - Q (The interval gradually becomes longer and the output C
The duty ratio of is decreasing. The force of this binding input 1- becomes low F, and the voltage 1i also becomes low as shown in Figure 5 (A) and Figure 6 (A) on the right. The ELI timer IC 20 is triggered when the input F reaches the rl- level, and after a predetermined delay from that point, the 7-rip 70 knob 17 is reset and the output from the AND gate 15 is reset as shown in FIG. 5 (E). Forbid output.

Therefore, if the non-commercial load is applied, the oscillation of the inverter circuit or the electromagnetic perforation will occur after the human power is gradually reduced.
ilσ no color C city 11ru. O ゛6 pieces of unnoji4j sexual horns'! It goes without saying that the switching elements can be protected in the event of an accident. There is no abnormal sound when I'I' city. And multiple electric appliances (like a direct cooker, the power source can be used together to generate multiple voltages in one unit) 11
If a heating device is installed in parallel, the device I''7 will be activated immediately upon detection of an unsuitable load from 1 to 11.
If υ1 stops, the power supply voltage should be suddenly removed.
) will affect the unsuitable load detection function of other devices; Similar inappropriate load detection occurs for 1"1' as well.

The electromagnetic induction heating device according to 1.17 is equipped with a current detection circuit that detects the input to the rice cake (i), %f, and the 'rl II, 4 Kakuda times 11 each. more irreverent 1
When a load is detected, the current control circuit reduces the current by 1fc of the rickshaw, and the current 1(・II (1111 times the input current decreases from VC to 1), then the input to the load k1
';' Since it is equipped with a stop path circuit for J, J4 +lθ, there is no 71gI characteristic. If WII stops F at /7″, VC'/+1. 'iir
It is possible to realize an electric heating device fQ7 that does not overwhelm others and does not cause unnecessary surprises.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram of 815 inverter circuits for one device and one device, Figure 2 is a schematic circuit diagram of a control circuit, and Figures 3 to 6 are 110 parts of the circuit diagram. This is a time chart. 5, inverter circuit 5a...induction heating coil 5c,
5e...Switching transistor 9,10...
Father flow device 1B, 14.18.19 Comparator 16
．． 17...Flip 70 knob 20...Timer IC 4th block Jl: 1-

Claims (1)

[Claims] A current detection circuit that detects the input current to the 1° port (+II), and an nZ flow control l:iil ma 1 that reduces the input terminal when an unsuitable load is detected by the meter weight 14 detection circuit, The 'i ((, (M, input '1' by the first circuit) 1 pivot stop time 1, which stops the input to the negative 111 after the 1 current decreases 1. Features: ``City magnetic induction 4V heating''i+:'r.