JP2000133414A - Heater control apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heater control apparatus which can realize equal temperature control characteristic without adjustment for dual system input voltages which are different by a factor of about two. SOLUTION: A a heater control apparatus is constituted by a energization control circuit 9 having a bridge diode 10, a current controlling resistor 11, a Zener diode 12, photocoupler 13 and a energizing signal generating circuit 14. The control circuit 9 discriminates line of input voltage. When the line of input voltage is low, the control circuit 9 makes full-wave energization to a heater 3. On the other hand, when the line of input voltage is high, the control circuit 9 makes a quarter wave energization to the full-wave energization to the heater 3. Thus the control circuit 9 generates an energizing signal g2 so that temperature control characteristics in the two lines are equal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heater control device used for a laminator or the like.

[0002]

2. Description of the Related Art FIG. 8 shows a prior art heater control apparatus, wherein 1 is a temperature control circuit, 2 is a power element comprising a bidirectional conducting element such as a triac, 2A is an AC power supply, 3 is a power element 2 and an AC power supply 2A. Heater powered by
Is a temperature detecting element such as a thermistor for detecting the temperature of the heater 3 or the object to be heated by the heater 3.

In such a conventional heater control device, a temperature control circuit 1 receives a detected temperature signal a output from a temperature detecting element 4 and outputs an energization control signal b for controlling a power element 2. The power element 2 is controlled by an energization control signal b, and energizes the heater 3.

The temperature control circuit 1 receives a detected temperature signal a from the temperature detecting element 4 and outputs a detected temperature processing signal c of a predetermined level, and is heated by the heater 3 or the heater 3. A temperature setter 6 composed of a regulator or the like for setting the control temperature of the object to be heated, and a comparator 7 for comparing a set temperature signal d output from the temperature setter 6 and a detected temperature processing signal c from the detected temperature processing circuit 5. And the comparator 7
And a power element driver 8 that receives a control signal e output from the controller 3 and generates an energization control signal b. The temperature of the heater 3 or the object to be heated by the heater 3 is set by the temperature setter 6.
Is controlled to be constant around the temperature set in.
The power element driver 8 may be composed of, for example, a phototriac coupler, a resistor, and the like as shown in the figure.

FIG. 9 shows the control characteristics of the prior art.
In FIG. 3A, the hatched waveform indicates the heater current, and the solid and broken waveforms indicate the input voltage. Also, in FIG. 2B, c is a detected temperature processing signal, d is a set temperature signal, e in FIG. 3C is a control signal, and FIG.
B is an energization control signal. Next, the operation of the conventional heater control device will be described with reference to FIG. When the input voltage from the AC power supply 2A is applied to the heater 3 via the power element 2 as shown in FIG. 2A, the detected temperature processing signal c is changed to the set temperature signal d as shown in FIG. When lower,
The control signal e output from the comparator 7 becomes a low-level signal (L) as shown in FIG. 4C, and the power element driver 8 receives the input voltage from the AC power supply 2A as shown in FIG. The (+) or (-) pulse conduction control signal b is output at the timing when the (sine wave) becomes 0V. Power element 2
The conduction is controlled in response to the (+) or (-) pulse conduction control signal b, and the heater current indicated by hatching in FIG.
For example, the power is supplied to the heater 3 in a section from time t1 to t2 and time t3 to t4. On the other hand, as shown in FIG. 2B, in a section where the detected temperature processing signal c is higher than the set temperature signal d, for example, in a section from time t2 to t3, the control signal e output from the comparator 7 is As shown in (c), the level becomes high (H), and the power element driver 8 holds the energization control signal b at 0V. The power element 2 receives the energization control signal b held at 0 V and, as shown in FIG.
→ In the section of t3, the power supply to the heater 3 is stopped. Hereinafter, by repeating this operation, the temperature of the heater 3 or the object to be heated by the heater 3 is controlled so as to be constant around the set temperature corresponding to the set temperature signal d set by the temperature setter 6. .

[0006]

Since there is a time delay in heat transfer between the heat generating portion of the heater 3 and the temperature detecting element 4, the detected temperature signal a detected by the temperature detecting element 4
Is controlled with a certain displacement width. The displacement width differs depending on the input voltage. As the input voltage increases, the displacement width increases, and the average temperature also increases. Therefore, in the conventional heater control device that allows two input voltages different from each other by about twice, the average value of the detected temperature signals a when the low system input voltage is applied and when the high system input voltage is applied is made equal. It is necessary to adjust the set temperature signal d by the temperature setter 6. It should be noted that the displacement width of the detected temperature signal a cannot be adjusted in the prior art.

The present invention has been made in order to solve the above-mentioned problems (problems) of the conventional device, and has the same temperature control characteristics with respect to two input voltages (for example, AC100V and AC200V) which are different by about twice. It is an object of the present invention to provide a heater control device realized without adjustment.

[0008]

According to the present invention, there is provided a heater control device comprising: a power element for energizing a heater; and a temperature detecting element for detecting a temperature of the heater or a body to be heated heated by the heater. A temperature control circuit for receiving a signal and generating an energization control signal for the power element, wherein the heater control device accepts input voltages of two systems that differ by about two times. The system of the input voltage is determined, and if the input voltage is low, the heater is energized in full-wave. If the input voltage is high, the heater is automatically energized to 1/4 of the full-wave energized. It is configured to generate the energization signal in such a way that the energization signal is generated. In this case, the heater is energized by a full-wave rectifier that full-wave rectifies the input voltage from the AC power supply, a current limiting resistor that limits the current from the AC power supply, and an input voltage that determines the input voltage from the AC power supply. A Zener diode for setting a judgment reference value,
A photocoupler that outputs an input voltage determination signal, an energization signal generation circuit that receives the input voltage determination signal and generates a first energization signal, and a transistor that receives the first energization signal and outputs a second energization signal This can be performed by an energization control circuit composed of The energization signal generation circuit uses an inverter gate and three D-flip-flops to generate a control signal to energize the heater during a half cycle of two AC cycles, and to apply full-wave energization to the heater. , 1/4 wave. Alternatively, instead of this, an energization signal generation circuit uses an inverter gate and five D-flip-flops to generate a control signal for energizing the heater for one cycle of four AC cycles, thereby energizing the heater with full wave. However, a configuration may be adopted in which energization of 1/4 wave is performed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In FIG. 1, the same components as those in the related art are denoted by the same reference numerals as those in FIG.

In the present invention, as shown in FIG. 1, the conventional heater control device shown in FIG. 8 includes a bridge diode 10 as a full-wave rectifier for full-wave rectifying an input voltage from the AC power supply 2A and a AC power supply 2A. Current limiting resistor 11 for limiting the current, a Zener diode 12 for setting an input voltage determination reference value for determining an input voltage from the AC power supply 2A, and a photocoupler 1 for outputting an input voltage determination signal f.
An energization control circuit 9 comprising an energization signal generation circuit 14 for receiving an input voltage discrimination signal f and generating an energization signal g1 and a transistor 15 serving as an inverting switching element for receiving the energization signal g1 and outputting an energization signal g2. There is a structural feature of the present invention in that the configuration is provided. The specific configuration of the energization signal generation circuit 14 has a function of receiving the input voltage discrimination signal f from the photocoupler 13 and forming it as a quarter energization first energization signal g1, as described later. It may be configured by a logic circuit element as described above.

FIG. 2 shows a first embodiment of the heater control device according to the present invention.
The waveforms indicated by hatching in FIG. 3A indicate the heater current, the waveforms indicated by the solid and broken lines indicate the input voltage, and Vz indicates the input voltage determination reference value. It shows the voltage that becomes In FIG. 2B, c is a detected temperature processing signal, d is a set temperature signal, f in FIG. 3C is an input voltage discrimination signal, and g2 in FIG. 2D is a second energizing signal. . The first energization signal g1 is the second energization signal g2 of (d).
Are not shown in FIG. Also, e in FIG. 6E is a control signal, and b in FIG. Next, the operation of the heater control device of the present invention will be described with reference to FIG. As shown in FIG. 2A, when an input voltage is applied from the AC power supply 2A to the heater 3 via the power element 2, the absolute value of the input voltage is determined by an input voltage determination criterion set by the Zener diode 12. When the value is smaller than the value (for example, in the section from time t1 to t2), the input voltage discrimination signal f becomes high level (H) as shown in FIG.
On the other hand, when the absolute value of the input voltage is larger than the input voltage determination reference value (for example, in the section from time t2 to t3), the input voltage determination signal f becomes low level (L) as shown in FIG. ). Therefore, when the maximum value (absolute value) of the input voltage is greater than the input voltage determination reference value, the input voltage determination signal f repeats high level (H) and low level (L) as shown in (c). It becomes a pulse signal. Also,
The energization signal generation circuit 14 receives the input voltage determination signal f,
An energization signal g1 having a quarter frequency is output. The transistor 15 receives the energization signal g1 and outputs an energization signal g2 as shown in FIG. The power element driver 8
In response to the energizing signal g2 shown in (c) and the control signal e from the comparator 7 shown in (e), the energizing signal g2 becomes high level (H).
Only when the control signal e is at the low level (L), the (+) or (-) pulse conduction control signal b is changed to (f) at the timing when the input voltage (sine wave) from the AC power supply 2A becomes 0V. Output as shown. The power element 2 energizes the heater 3 according to the energization signal b. Therefore, the heater 3 is controlled by the heater control device of the present invention by energizing 1/4 wave of the waveform shown by the solid line in FIG.

An energization signal generation circuit which is a first example of a specific configuration diagram of the energization signal generation circuit 14 shown in FIG. 1 is indicated by reference numeral 14A in FIG. As shown in the drawing, the energization signal generation circuit 14A includes one inverter gate 16 and three D-flip-flops 17a, 17b, 17c and a resistor 18,
It is constituted by a capacitor 19. The D-flip-flop 17b receives the input voltage discrimination signal f from the photocoupler 13, and receives the input voltage discrimination signal f from low level (L) to high level (H) as shown in (c) of the timing chart of FIG. Input determination signal f at the rising timing of
In contrast, a divide-by-2 signal i2, which is a divide-by-2 signal, is generated. D-
The flip-flop 17c receives the divided-by-2 signal i2, and receives the input voltage discrimination signal f at the rising timing from the low level (L) to the high level (H) of the divided-by-2 signal i2 as shown in FIG. , To generate a divide-by-four signal j. The inverter gate 16 receives the input voltage determination signal f, and receives the input voltage determination signal f as shown in FIG.
To generate an inverted signal h. The D flip-flop 17a receives the inverted signal h and the divide-by-4 signal j, and only when the divide-by-4 signal j is at the high level (H) as shown in FIG. → High level (H)
At the rising timing of the inversion signal h, the energization signal g1 is generated by dividing the inversion signal h by two. Since the energization signal g1 is held at the high level (H) when the divide-by-4 signal j is at the low level (L), the low level (L) of one cycle of the inverted signal h is output once every four cycles of the inverted signal h. ) Is output. Although not shown, the waveform of g2 is a waveform obtained by inverting the waveform of g1.

The second example of the energization signal generation circuit 14 shown in FIG. 1 is distinguished from the energization signal generation circuit 14A of FIG.
FIG. 5 shows a specific configuration diagram indicated by. As shown in the drawing, the energization signal generation circuit 14B includes one inverter gate 16 and five D-flip-flops 17a, 17
b, 17c, 17d and 17e, a resistor 18, and a capacitor 19 are connected. The D-flip-flop 17c receives the input voltage determination signal f from the photocoupler 13.
Then, as shown in (c) of the timing chart of FIG. 6, the input voltage determination signal f is divided by 2 at the rising timing from the low level (L) to the high level (H) of the input voltage determination signal f. A two-frequency-divided signal i2 is generated. The D-flip-flop 17d receives the divide-by-2 signal i2, and as shown in FIG.
→ Generate a divide-by-4 signal j, which is a divide-by-4 signal, with respect to the input voltage discrimination signal f at the rising timing of the high level (H). The D-flip-flop 17e receives the divide-by-4 signal j and receives the input voltage discrimination signal f at the rising timing of the divide-by-4 signal j from low level (L) to high level (H) as shown in FIG. , A divide-by-8 signal k which is a divide-by-8 signal is generated. The inverter gate 16 receives the input voltage discrimination signal f and generates an inverted signal h obtained by inverting the input voltage discrimination signal f as shown in FIG. The D-flip-flop 17a receives the inverted signal h, and as shown in (f) of the figure, the inverted signal h is changed from low level (L) to high level (H).
At the rising timing of the inverted signal h, the divide-by-2 signal i1 is generated. The D-flip-flop 17b receives the divide-by-2 signal i1 and the divide-by-8 signal k, and the divide-by-8 signal k becomes high level (H) as shown in FIG.
Only when the inverted signal h rises from the low level (L) to the high level (H) of the divide-by-2 signal i1 by 4
An energization signal g1 for frequency division is generated. This energization signal g1
Outputs a low level (L) for two periods of the inverted signal h at the timing of once every eight periods of the inverted signal h, since the high frequency (H) is held when the divide-by-8 signal k is low (L). I do. Therefore, when the second energization signal generation circuit 14B is applied, the heater control device shown in FIG.
Control characteristics. The hatched waveform portion shown in FIG. 3A indicates the heater current. Although this current waveform is different from the first control characteristic shown in FIG. 2, the heater is controlled by 1/4 wave energization. That is, when the control signal e shown in FIG. 7E is at a low level (L) (when the detected temperature processing signal c is lower than the set temperature signal d), the AC power supply shown by the solid line and the broken line in FIG. The heater current indicated by hatching is applied once every four cycles of the input voltage from 2 A (one cycle). In this example, since the 1/4 wave energization in which bidirectional input voltage is applied is different from the above-described example of 1/4 wave energization in which only one half wave of the input voltage is applied, harmonics for the AC power supply 2A are used. The current can be reduced.

When the maximum value (absolute value) of the input voltage is smaller than the input voltage determination reference value as described above, the input voltage determination signal f is maintained at a high level (H). The energization signal generation circuit 14 outputs a low level signal when the input voltage determination signal f maintains a high level (H) for a period of one cycle or more of the AC power supply 2A.
In order to output the energization signal g1 of (L), the transistor 15
Is turned off, and the heater is controlled by full-wave energization. Therefore, the input voltage determination reference value may be set to be larger than the maximum value of the input voltage of the low system and smaller than the maximum value of the input voltage of the high system.

As described above, the voltage applied to the heater 3 can be effectively made equal by changing the method of supplying power to the heater 3 for the two systems of high and low input voltages. That is, assuming that the effective value of the AC voltage is Erms1 and the maximum value is Em1, it is expressed by the following equation (1). Erms1 = Em1 / √2 (1)

The effective value of the quarter-wave voltage (the solid line portion of the input voltage) shown in FIG. 2 is expressed by the following equation (2), where the effective value is Erms2 and the maximum value is Em2.

Here, the effective value Erms2 when a quarter-wave of the AC voltage effective value Erms1 is applied is represented by the following equation (3). Erms2 = √2 · Erms1 / √8 = Erms1 / 2 (3)

Therefore, the effective value when the full-wave AC voltage is applied and the effective value when the double AC voltage is applied to the quarter wave are equal. Also in the case of the heater energizing method shown in FIG. 5, although the proof is omitted, the effective value when the AC voltage is energized by full-wave and when the doubled AC voltage is energized by 1/4 wave are equal.

In the heater control device of the present invention, the input voltage system is discriminated by an energization control circuit in order to allow input voltages of two systems that differ by about two times. If the input voltage is high and the input voltage is high, an energization signal is generated so that the energization that becomes 1/4 wave to the full-wave energization is automatically performed to the heater. Since the heater is energized with a substantially equal voltage, it is not necessary to adjust the temperature setting for the system of the input voltage unlike the conventional method.

[0020]

Since the heater control device of the present invention is configured as described above, it has the following excellent effects. (1) In the heater control device according to the present invention, an energization signal for switching to full-wave energization and quarter-wave energization can be automatically generated by an energization control circuit in accordance with input voltages of two systems that differ by about twice. . (2) Therefore, the same temperature control characteristics can be realized without adjustment for two input voltages of about two times different from each other.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a heater control device according to the present invention.

2 is a first control characteristic diagram in a case where the energization signal generation circuit 14A shown in FIG. 3 is applied to the energization signal generation circuit 14 of FIG. 1 and a heater control device is operated.

FIG. 3 is a block diagram illustrating a first configuration example of an energization signal generation circuit used in the heater control device of the present invention.

FIG. 4 is a timing chart showing input / output signal waveforms of various parts of the energization signal generation circuit of FIG. 3;

FIG. 5 is a block diagram showing a second configuration example of the energization signal generation circuit used in the heater control device of the present invention.

6 is a timing chart showing input / output waveforms of each part of the energization signal generation circuit of FIG.

FIG. 7 is a second control characteristic diagram when the energization signal generation circuit 14B shown in FIG. 5 is applied to the energization signal generation circuit 14 of FIG. 1 and the heater control device of the present invention is operated.

FIG. 8 is a block diagram illustrating a configuration of a conventional heater control device.

FIG. 9 is a control characteristic diagram of a conventional heater control device.

[Explanation of symbols]

 1: Temperature control circuit 2: Power element 2A: AC power supply 3: Heater 4: Temperature detection element 5: Detected temperature processing circuit 6: Temperature setter 7: Comparator 8: Power element driver 9: Power supply control circuit 10: Bridge diode 11: Current limiting resistor 12: Zener diode 13: Photocoupler 14, 14A, 14B: Energizing signal generating circuit 15: Transistor 16: Inverter gate 17a to 17e: D-flip-flop a: Detected temperature signal b: Energizing control signal c: Detected temperature processing signal d: Set temperature signal e: Control signal f: Input voltage discrimination signal g1, g2: Energization signal h: Inversion signal i1, i2: Divide-by-2 signal j: Divide-by-4 signal k: Divide-by-8 signal

Claims (4)

[Claims] An electric power control signal for a power element for energizing a heater, and a power control signal for the power element in response to a detected temperature signal from a temperature detecting element for detecting a temperature of the heater or a body to be heated heated by the heater. And a temperature control circuit having a temperature control circuit that generates two different input voltages. The heater control device receives input voltage from an AC power supply and determines a system of the input voltage. In the case of a system, the heater is energized by full-wave, and in the case of a system having a high input voltage, energization to become 1/4 wave with respect to energization of the full-wave is automatically performed to the heater. Control device. 2. The power supply of the heater determines a full-wave rectifier for full-wave rectifying an input voltage from an AC power supply, a current limiting resistor for limiting a current from the AC power supply, and an input voltage from the AC power supply. A zener diode for setting an input voltage determination reference value, a photocoupler for outputting an input voltage determination signal, an energization signal generation circuit for receiving the input voltage determination signal and generating a first energization signal, and a first energization signal 2. The heater control device according to claim 1, wherein the current is controlled by an energization control circuit including a transistor that outputs a second energization signal. 3. The energization signal generation circuit uses an inverter gate and three D-flip-flops to generate a control signal for energizing a heater in a half cycle of two AC cycles, and to generate a full-wave control signal to the heater. The heater control device according to claim 2, wherein the energization is performed such that a quarter wave is applied to the energization. 4. The energization signal generation circuit uses an inverter gate and five D-flip-flops to generate a control signal for energizing a heater in one cycle of four AC cycles, and energize a full-wave heater. 3. The heater control device according to claim 2, wherein a current is applied so that the current becomes 1/4 wave.