JPH0115993B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a heater drive power supply device, and more particularly, to a heater drive power supply device, and more particularly, a power supply device that supplies power suitable for the power consumption of the heater even if the magnitude of the voltage supplied to the heater changes. The present invention relates to a heater drive power supply device that can be controlled to

[Prior art and its problems] If a heater is used within its rated power, it can be used for at least a specified lifespan, but if it is used at a power higher than its rated power, it becomes susceptible to disconnection. , the lifespan will be shortened. Therefore, when the heater is used within the rated power, for example, when the voltage supplied to the heater is within a predetermined range, the heater does not become easily disconnected and can be used for a predetermined life or longer, which is preferable.

By the way, if you export a heater made for domestic use at 100 volts to a foreign country and use it in a foreign country where the commercial voltage is 200 volts, approximately four times as much power will be supplied to the heater. As a result, the heater becomes easily disconnected, shortens its lifespan, and cannot be used in the foreign country in its current state.For this reason, conventionally,
A separate heater was prepared for use in foreign countries, or an intermediate tap corresponding to various voltages was provided in the power transformer, and by switching this intermediate tap, the appropriate voltage was supplied to the heater.
However, in the method of preparing another heater,
It is necessary to prepare various heaters for different countries with different voltages, which is undesirable from the standpoint of inventory management, process control, etc. This is especially true when the heater is built into a device and shipped as a product. , there is a problem in that both inventory management and process management become more complicated. In addition, in a method in which a power transformer with intermediate taps corresponding to various voltages is provided together with the heater, only one type of heater is required, but an extra power transformer is required, and the transformer is large because it has various intermediate taps. Become,
There are problems in that it is uneconomical and requires a large space.

[Objective and Summary of the Invention] In view of the above-mentioned conventional circumstances, an object of the present invention is to make it possible to keep the power supplied to the heater within the rated power of the heater even if the power supply voltage supplied to the heater changes; The object of the present invention is to provide a heater drive power supply device that can standardize a heater or a device incorporating a heater, and can be made economical and relatively compact.

In order to achieve the above object, the heater drive power supply device of the present invention detects the zero voltage point of the AC input voltage, counts this zero voltage detection signal in a counting selection circuit, and controls the heater according to the different power supply voltages used. Switching means that generates an output signal every predetermined count value set in advance according to the power supply voltage in order to limit the input power to within the rated power, and is connected in series to the heater based on this output signal. is activated, and the alternating current input voltage is supplied to the heater only during the subsequent half cycle of the alternating current input voltage.

[Embodiments of the Invention] The present invention will be described below with reference to illustrated embodiments.

In the heater drive power supply device showing one embodiment of the present invention shown in FIG. It's getting old. Furthermore, a zero voltage point detection circuit 9 is connected between the terminals 1 and 3. This zero voltage point detection circuit 9 detects the zero voltage point of the AC input voltage, generates a zero voltage detection signal at each zero voltage point, and supplies this zero voltage detection signal to the next stage counting selection circuit 11. It's getting old. The count selection circuit 11 counts the zero voltage detection signals supplied from the zero voltage point detection circuit 9, generates an output signal every time this count value reaches a predetermined count value that has been selected and set in advance, and generates an output signal. is supplied to the gate of the triac 5 via the transformer 13 to trigger the triac 5, and the counting result is reset by this output signal. put it here,
The predetermined count value is set corresponding to the AC input voltage supplied between the terminals 1 and 3, and this selection setting is made by, for example, a rotary switch,
This can be achieved by various methods such as jumper wire, number buttons, etc., whereby the set value is compared with the result of counting the zero voltage detection signal, and if both match, the said output signal is generated. This is how it has become. That is, when this output signal is supplied to the gate of the triax 5 via the transformer 13 and the triax 5 is triggered, the triax 5 becomes conductive, thereby supplying the alternating current input voltage to the heater 7. generates fever. Due to its nature, the period during which the triax 5 is conducting is the period from when it is triggered and conducts until the alternating current input voltage supplied to the triax 5 becomes out of phase. After this period, the next It remains in a cut-off state until an output signal is supplied from the counting selection circuit 11 again.

Next, the operation of the heater drive power supply device of FIG. 1 will be explained with reference to the waveform diagram of FIG. 2.

As heater 7, it is a 100 volt heater, that is, if the resistance of the heater is R, its rated power is
Use a heater with 100 ² /R watts, and connect terminal 1,
A case will be explained in which an AC voltage of 100 volts is supplied between the two terminals. In this case, it is assumed that the predetermined count value in the count selection circuit 11, which is set by the rotary switch, jumper wire, etc., is set to a value of "1" as described above. Note that this setting is made when the device incorporating this heater and heater drive power supply device is shipped from the factory.
This can be done in the factory or on-site after arriving at the site where this equipment will be used.

In the heater drive power supply device in which the predetermined count value in the count selection circuit 11 is set to "1" in this way,
When an AC voltage of 100 volts is supplied between terminals 1 and 3 as shown by a in Figure 2, this AC voltage is
The zero voltage point is detected by the zero voltage point detection circuit 9, and a zero voltage detection signal as shown in FIG. The count selection circuit 11 counts this zero voltage detection signal, and this count value is compared with the predetermined count value. Now, as mentioned above, this predetermined count value is set to "1", so every time the count value in the counting circuit 11 becomes "1", an output signal is generated from the count selection circuit 11, and the transformer 13 to the gate of the triac 5, and this output signal is supplied to the count selection circuit 1.
1, so that the count selection circuit 11 can count the zero voltage detection signal from the zero voltage point detection circuit 9 again from the beginning.
As a result, from the count selection circuit 11, b in FIG.
As shown in , an output signal is generated at all zero voltage points of the AC input voltage, and this signal is supplied to the gate of the triac 5 through the transformer 13 to make the triac 5 conductive. The same AC voltage as the alternating current voltage between the terminals 1 and 3 is supplied through the terminals 1 and 3, and the heater 7 generates heat due to this supplied voltage. In this case, the power consumed by the heater 7 is equal to or less than the rated power mentioned above.
100 ² /R Watts.

Next, we will install a device using this same heater 7 for 200
The case where it is used with an AC input voltage of volts will be explained.

In this case, if an AC voltage of 200 volts is directly supplied to the heater 7, the power of the heater 7 is 200 ² /
R Watts, which is the aforementioned rated power of heater 7.
Since it is four times 100 ² /R, the predetermined count value in the count selection circuit 11 described above is set to the value "4" as a value corresponding to 200 volts. As a result, the output signal from the count selection circuit 11 is generated every time four zero voltage detection signals are counted, as shown by c in FIG.
is triggered, and AC voltage is supplied to the heater 7 at a rate of one half cycle every four half cycles, as shown by d in FIG. 2, when calculated by the number of half cycles of the AC input voltage. Therefore, in this case, the power consumed by the heater 7 is 200 ² /(4R) Watts=100 ² /R, which is the rated power of the heater 7, as in the case where the AC input power is 100 volts. For this reason,
Even if the AC input voltage reaches 200 volts, heater 7
can be used at its rated power without requiring too much power.

[Effects of the Invention] As explained above, according to the present invention, the number of half-cycles of the AC input voltage that is repeatedly supplied to the heater can be varied in accordance with the value of the AC input voltage. Even if the voltage changes, a constant amount of power is always supplied to the heater, so even when exporting to a foreign country where the voltage is different from that in Japan, it is possible to use a heater with a different rating for each country with a different voltage. There is no need to manufacture and stock devices incorporating heaters, it is only necessary to manufacture and stock one type of heater or devices incorporating this heater, and it is possible to standardize heaters or devices incorporating this heater. It also makes inventory management and process management easier. Furthermore, since it can be configured using integrated circuits and small transformers, it can be made smaller and relatively inexpensive.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a heater drive power supply device showing one embodiment of the present invention, and FIG. 2 is a waveform diagram of each part of the heater drive power supply device of FIG. 1. 5...Triack, 7...Heater, 9...Zero voltage point detection circuit, 11...Counting selection circuit, 13
……Trance.

Claims (1)

[Claims] 1. A zero voltage point detection circuit that detects the zero voltage point of the AC input voltage and generates a zero voltage detection signal, and a zero voltage point detection circuit that counts the zero voltage detection signals from the zero voltage point detection circuit, and a count selection circuit that generates an output signal every predetermined count value set in advance according to the power supply voltage used in order to limit the power input to the heater within the rated power; and a count selection circuit connected in series to the heater; 1. A heater driving power supply device comprising switching means that is operated by an output signal of a counting selection circuit and supplies the AC input voltage to the heater only for a half cycle of the AC input voltage following the output signal.