CN201226443Y

CN201226443Y - Self-locking protection device for heating electric appliance

Info

Publication number: CN201226443Y
Application number: CNU2008201268099U
Authority: CN
Inventors: 李荣明; 周晓明; 艾志强
Original assignee: DONGGUAN QIANFENG ELECTRONICS Co Ltd
Current assignee: DONGGUAN QIANFENG ELECTRONICS Co Ltd
Priority date: 2008-07-01
Filing date: 2008-07-01
Publication date: 2009-04-22
Anticipated expiration: 2018-07-01

Abstract

The utility model relates to the technical field of electrical equipment, in particular to a protector for such electric heating appliances as an electromagnetic oven. The protector comprises a detection signal generation unit, a base comparison unit and a self-locking drive unit. The detection signal generation unit detects the abnormal work of an electric heating appliance and generates a signal to be sent to the base comparison unit; the base comparison unit generates a drive signal to control the self-locking drive unit; and the self-locking drive unit controls the work of the IGBT of the electric heating appliance. By adopting the protector, the abnormal work of the electric heating appliance is detected through the detection signal generating unit which can cooperate with the base comparison unit and the self-locking drive unit to intermit the drive signal of the IGBT and stop the electric heating appliance from working, thus protecting the electric heating appliance by self-locking. By adopting the proposal of a temperature-sensitive resistance probe, the circuit can play a role as a fuse, which is very precise and can be recovered automatically as well as very practical.

Description

The self-locking protecting device of heating electrical appliance

Technical field:

The utility model relates to technical field of electrical equipment, refers in particular to the protective device that is used for heating electrical appliances such as electromagnetic oven.

Background technology:

For heating electrical appliances such as electromagnetic ovens, generally can be provided with protective device, take place to prevent the accident that the heating electrical appliance operation irregularity is caused.Many companies use fuse to be protected, and insert in the heater circuit with fuse, in case take place unusually then fuse disconnects, stop heating electrical appliances such as electromagnetic oven, as adopting thermal cut fuse monitoring heating-up temperature, when occurring overheatedly then fusing, reach protection.But because temperature fuse has irrecoverable property, must change after the fusing, bothersome; Moreover, may be influential under strong magnetic field circumstance to temperature fuse (because the temperature fuse body is a metal), safety factor is not high, the real protection poor effect.

Summary of the invention:

The purpose of this utility model is to provide a kind of effect that can play fuse, the self-locking protecting device of the heating electrical appliance that can recover automatically again.

For achieving the above object, the utility model adopts following scheme to realize:

The self-locking protecting device of heating electrical appliance; this device has detection signal generating unit, benchmark comparing unit and self-locking driver element; the detection signal generating unit detects the abnormal work of heating electrical appliance and produces signal conveys gives the benchmark comparing unit; produce drive signal control self-locking driver element by the benchmark comparing unit, the self-locking driver element is then controlled the IGBT work of heating electrical appliance.

The detection signal generating unit has a transducer and a comparator, the benchmark comparing unit has a comparator and ultramagnifier, and the self-locking driver element has another group comparator and ultramagnifier, wherein the in-phase end of the comparator of benchmark comparing unit inserts a reference voltage, the signal of this comparator output divides two-way to transmit, one the tunnel feeds back backward end in comparator through ultramagnifier, another road is transported to the in-phase end of the comparator of self-locking driver element, the end of oppisite phase of comparator inserts a reference voltage, when comparator is exported a high level, connect the triode Q1 conducting of comparator output terminal and the drive signal of the IGBT of heating electrical appliance is pulled down to ground, end the drive signal of IGBT; The output of the comparator of above-mentioned detection signal generating unit is connected to the ultramagnifier of benchmark comparing unit, is dragged down the end of oppisite phase voltage of comparator by ultramagnifier.

Transducer is a thermistor.

In-phase end in the comparator of benchmark comparing unit inserts a variable resistor R, to regulate reference voltage.

The utility model can be detected the abnormal work of heating electrical appliance by the detection signal generating unit, and with benchmark comparing unit and self-locking driver element cooperation, by the drive signal of IGBT, stop heating electrical appliance work, reach the self-lock protection effect.Adopt the thermistor (temperature) sensor scheme, this circuit can play the effect of fuse fully, and accuracy is higher, can recover automatically, and is practical.

Description of drawings:

Accompanying drawing 1 is a frame principle figure of the present utility model;

Accompanying drawing 2 is an embodiment winding diagram of the present utility model.

Embodiment:

Below in conjunction with accompanying drawing the utility model is further specified:

Consult shown in Figure 1; the self-locking protecting device of the heating electrical appliance that the utility model provides; its this device has detection signal generating unit 10, benchmark comparing unit 20 and self-locking driver element 30; detection signal generating unit 10 detects the abnormal work of heating electrical appliance and produces signal conveys gives benchmark comparing unit 20; produce drive signal control self-locking driver element 30, the IGBT work of 30 control of self-locking driver element heating electrical appliance by benchmark comparing unit 20.

Consult shown in Fig. 1,2, detection signal generating unit 10 has a transducer 11 and a comparator 12 (LM339), and transducer 11 is a thermistor (temperature) sensor, and in order to detect cooking bottom temperature, transducer 11 is established one or more.Benchmark comparing unit 20 has a comparator 21 (LM339) and a ultramagnifier 22, and self-locking driver element 30 has another group comparator 31 (LM339N) and ultramagnifier 32, wherein the in-phase end of the comparator 21 of benchmark comparing unit 20 inserts a reference voltage, the signal of these comparator 21 outputs divides two-way to transmit, one the tunnel feeds back in the backward end of comparator 21 through ultramagnifier 22, another road is transported to the in-phase end of the comparator 31 of self-locking driver element 30, the end of oppisite phase of comparator 31 inserts a reference voltage, when comparator 31 outputs one high level, connect the triode Q1 conducting of comparator 31 outputs and the drive signal of the IGBT of heating electrical appliance is pulled down to ground, end the drive signal of IGBT; The output of the comparator 12 of above-mentioned detection signal generating unit 10 is connected to the ultramagnifier 22 of benchmark comparing unit 20, is dragged down the end of oppisite phase voltage of comparator 21 by ultramagnifier 22.

Operation principle:

If the bottom of a pan open sensor or not slotting, comparator 21 in-phase ends (reference voltage 2) of benchmark comparing unit 20 are higher than its backward end, comparator 21 output high level, the high signal in one road drags down its end of oppisite phase by ultramagnifier 22, so that in-phase end is higher than end of oppisite phase all the time; Therefore export high level all the time; other one road signal is added to the in-phase end of the comparator 31 of self-locking driver element 30; make its in-phase end be higher than its end of oppisite phase voltage (reference voltage 1); comparator 31 output high level; the Q1 conducting is pulled down to ground with the IGBT drive signal, by its ultramagnifier 32 comparator 31 in-phase end level is raised in addition, makes comparator 31 export high level always; IGBT does not end because of there being drive signal, plays a protective role thereby machine is not worked.If the bottom of a pan transducer 11 is because short circuit or temperature are too high; its resistance diminishes; when reaching uniform temperature, the in-phase end of comparator 12 is higher than end of oppisite phase, comparator 12 output high level; this signal drags down comparator 21 end of oppisite phase voltages by ultramagnifier 22; comparator 21 output high level drag down comparator 21 end of oppisite phase by ultramagnifier 22 again simultaneously, and comparator 21 is exported high level all the time like this; comparator 31 output high level play the protection purpose thereby IGBT is not worked.

Consult shown in Figure 2ly, insert a variable resistor R (R9) in the in-phase end of the comparator 21 of benchmark comparing unit 20, adjust the resistance of resistance R, scalable reference voltage size is also just further adjusted the operating temperature of thermistor (temperature) sensor 11 thus.Ultramagnifier 22 has diode D2, resistance R 2 and triode Q2, and ultramagnifier 32 has resistance R 11, diode D5 and D6.

Claims

1, the self-locking protecting device of heating electrical appliance; it is characterized in that: this device has detection signal generating unit (10), benchmark comparing unit (20) and self-locking driver element (30); detection signal generating unit (10) detects the abnormal work of heating electrical appliance and produces signal conveys gives benchmark comparing unit (20); produce drive signal control self-locking driver element (30) by benchmark comparing unit (20), self-locking driver element (30) is then controlled the IGBT work of heating electrical appliance.

2, the self-locking protecting device of heating electrical appliance according to claim 1, it is characterized in that: detection signal generating unit (10) has a transducer (11) and a comparator (12), benchmark comparing unit (20) has a comparator (21) and ultramagnifier (22), and self-locking driver element (30) has another group comparator (31) and ultramagnifier (32), wherein the in-phase end of the comparator (21) of benchmark comparing unit (20) inserts a reference voltage, the signal of this comparator (21) output divides two-way to transmit, one the tunnel feeds back in the backward end of comparator (21) through ultramagnifier (22), another road is transported to the in-phase end of the comparator (31) of self-locking driver element (30), the end of oppisite phase of comparator (31) inserts a reference voltage, when comparator (31) output one high level, connect the triode Q1 conducting of comparator (31) output and the drive signal of the IGBT of heating electrical appliance is pulled down to ground, end the drive signal of IGBT; The output of the comparator (12) of above-mentioned detection signal generating unit (10) is connected to the ultramagnifier (22) of benchmark comparing unit (20), is dragged down the end of oppisite phase voltage of comparator (21) by ultramagnifier (22).

3, the self-locking protecting device of heating electrical appliance according to claim 2 is characterized in that: transducer (11) is a thermistor.

4, the self-locking protecting device of heating electrical appliance according to claim 2 is characterized in that: the in-phase end in the comparator (21) of benchmark comparing unit (20) inserts a variable resistor R, to regulate reference voltage.