JPH0317984A - Constant power supplying device for heater heat cooker - Google Patents

Abstract

PURPOSE:To keep supply power to a heating body constant by controlling a Triac phase control circuit connected with the circuit of a heating body for the ON phase of an input power source by operation by change of applied voltages to the heating body. CONSTITUTION:A heating body or a heater 4 and a Triac 3 are serially connected between both terminals of a commercial AC power source 5, and a power source voltage detecting circuit 1 is connected between both terminals of the commercial power source 5 through a transformer 6. A Triac phase control circuit 2 for operating a gate circuit of the Triac 3 is connected on the output side of the power source voltage detecting circuit 1 for controlling a voltage applied to the heater 4. If the power source voltage is fluctuated to the rated voltage, therefore, complicated compensation in a heating times is not necessary, and the input to the heater can be kept constant in a predetermined fluctuation range constantly. Cooking is thus enabled by setting only a required cooking time for each sort of cooking.

Description

[Detailed Description of the Invention] Industrial Application Fields The present invention is directed to a constant power supply device for a microwave oven or other heater cooking device that uses an AC power source for heating. Kujumai's technology〉 In general, when the power supply voltage drops below the rated value, the constant power supply means for Jumai's control qr+ extends the heating time according to the width of the voltage drop. If the temperature rises, the heating time is shortened according to the range of fluctuation, so that the upstream conditioning is completed.

Problems to be Solved by the Invention> However, with the above means, since the cooking time differs depending on the food to be cooked, perfect cooking cannot be achieved even if the cooking time is determined centrally based only on the voltage fluctuation width. I!
Cooking times had to be corrected for every four products through complicated procedures.

In addition, when preheating food, that is, when automatically starting cooking at a certain time, it is necessary to set the cooking end time in advance, taking into account the increase or decrease in heating time. Judging from the results, there was a drawback that the heating time was longer.

Therefore, the present invention achieves the desired purpose by simply determining the required heating time for each food item and controlling the voltage so that the necessary heat output is always obtained without being affected by fluctuations in the power supply voltage. It is an attempt to deviate from this. Means for resolving the problem〉 A triac phase control circuit connected to the circuit of the heating element,
By controlling the voltage applied to the heating element by changing the voltage applied to the heating element, the O
N phases are controlled.

Effect> By making the heating element produce the rated heat output in response to a voltage lower than the rated value of the power supply, the ON phase of the input voltage is delayed when the power supply voltage fluctuates higher than the rated value. In addition, when the power supply voltage fluctuates to a level lower than the rated value, the ON phase of the input voltage is advanced and the input voltage phase to the heating element is controlled to keep the power supplied to the heating element constant.

Embodiments Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings.A heating element, that is, a heater 4 and a triac 3 are connected in series between both terminals of the commercial AC power source 5, and the commercial AC power source 5 is A power supply voltage detection circuit 1 is connected between both ends via a transformer 6, and a triac phase control circuit for operating the date circuit of the triac 3 is connected to the output side of the Ml source voltage detection circuit 1, and voltage is applied to the heater 4. The voltage is controlled.

In the present invention, as described above, the output voltage of the commercial AC power supply 5 is
? ! The i-source voltage detection circuit 1 detects voltage fluctuations, such as whether the output voltage remains at the rated voltage of the power supply 5, is higher or lower than this, and sends a signal regarding the voltage fluctuation to the triac phase control circuit. Based on this, the date voltage of the triac 3 is controlled, and the ON phase of the input voltage to the heater 4 is shifted in accordance with the state of the signal from the detection circuit 1, so that the input to the heater is always maintained. is kept constant.

Regarding the relationship between voltage and power, in order to be able to always supply the rated power (power consumption) to the heater 4 even if the output voltage of the commercial AC power supply fluctuates, it is necessary to anticipate the range of voltage fluctuations in advance and respond accordingly. The set output is used as the rated power of the heater 4.

That is, when the rated voltage of the power source is e0, the effective output corresponding to when the output voltage is reduced by 10 [%1] from the rated voltage e0, for example, is the rated power of the heater 4. Then, as shown in FIG. 2(a), the rated voltage e. In order to obtain the above effective output, the effective output is 90[%1
can be obtained.

Therefore, as shown in the t52 diagram (b), the output voltage e1 of the power supply 5 detected by the voltage detection circuit 1 is 10[
%], the effective output of the power corresponding to the output voltage e1 is increased by delaying the ON phase by a phase angle of 74[''] from the zero crossing of the rise of the output voltage e1.
1.8 [%] is obtained.

Further, as shown in FIG. 2(c), if the output voltage e2 of the 7fL source 5 detected by the voltage detection circuit 1 is lower than the rated voltage e0 by 10E%, in FIG. 2(.),
Since the heater 4 is able to produce 100[%] of heat output at an output voltage that is 10E% lower than the rated voltage e0, the rated power is applied to the heater 4 at the output voltage e2 from the zero cross of the rise of the potential. can be supplied. As described above, in the present invention, the rated power of the heater 4, for example, IOOOW, is obtained by ±10%1 of the variation range with respect to the rated value of the ffi source voltage, so that the commercial AC power supply If the voltage is within ±10% of the rated voltage, change the ON phase of the trifuku from 0 to 74 [”
If the phase is controlled within the range up to ], the rated power can always be supplied to the heater.

Note that, although the above example assumes that the fluctuation range of the power supply voltage with respect to the rated value is ±10 [%] as the range that is most likely to fluctuate for convenience, it is not limited to this value.

Effects of the Invention Since the present invention is as described above, even if the power supply voltage fluctuates from the rated voltage, there is no need to perform complicated heating time correction operations as in the past, and the input to the heater can be reduced. The present invention has advantages such as being able to always maintain the cooking time constant within the scheduled variation range, and making it possible to perform cooking by simply setting the required cooking time for each type of cooking.

[Brief explanation of drawings]

Figures 1 and 2 show embodiments of the present invention, Figure fjS1 is a circuit diagram of a constant power supply device, Figure fjS2 (.) is a rated voltage waveform diagram, and Figure 2 (b) is a diagram of the rated voltage. Figure 2(c) is an output voltage waveform diagram when the voltage is lower than the rated voltage. 1...Electric voltage detection circuit 2...Triac phase control circuit 3...Triac, 4...Heater 5...
Commercial AC power supply, co... Rated voltage e1... Output voltage higher than the rated value e2... Output voltage lower than the rated value

Claims (1)

[Claims] 1. A heating element and a triac are connected to a commercial power source, and a phase control circuit is provided in the gate circuit of the triac to control the ON phase of the triac by receiving a signal from a voltage detection circuit of the commercial power source. Constant power supply device for heater heating cooker.