JP2001249726A - Control system and temperature controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To highly precisely and stably control the temperature or heating state of a heater even at the time of using a power source whose power source output is unstable. SOLUTION: This control system is provided with a switcher 6 arranged between a power source 2 and a heater 4 to be driven by this power source, a temperature controller 10 for outputting a temperature control output, and a switcher control part 14 for controlling the opening and closing of the switcher from the state of the output of the power source and the state of the temperature control output. At the time of controlling the output of the power source, and supplying it to the heater, and controlling the temperature or heating state of the heater, the heater is controlled from the state of the output of the power source and the state of the temperature control output related with the temperature or heating state of the heater obtained from the temperature controller.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control system for controlling the temperature or heat generation of a control target such as a heater for heating an object to be heated, and a temperature controller used for the control system.

[0002]

2. Description of the Related Art A conventional control system of this type includes a thyristor or an MO between an AC power supply and a heater to be controlled.
A switch such as an SFET is connected, and the current heat generation temperature of the heater is detected by a temperature sensor, and a signal related to the detection is input to the temperature controller.
In some cases, the on-duty of the switch is controlled so that the difference between the current heating temperature of the heater and the target heating temperature obtained from the signal is eliminated, thereby controlling the heating temperature of the heater to the target heating temperature. In other words, when the current heat generation temperature of the heater is lower than the target heat generation temperature, the on-duty of the switch is extended to increase the heat generation temperature of the heater so as to approach the target heat generation temperature. The duty is shortened so that the heat generation temperature of the heater is controlled so as to approach the target heat generation temperature.

There are various applications or applications of such a control system. For example, the control system is used for controlling the heat generation temperature of a heater when the wafer is heated by a heater in a semiconductor wafer manufacturing process. There is a system to be.

[0004]

In such a control system, the entire system is configured and controlled for highly accurate control of the heat generation temperature on the assumption that the power supply voltage is stable. Therefore, even if the power supply is in an area where power supply conditions are poor or where power supply conditions are good, and a power supply with an unstable power supply itself is used, the heating temperature of the heater reaches the target heating temperature quickly and with high accuracy. Alternatively, there is a problem that high stability cannot be maintained.

Accordingly, the present invention provides a method for controlling the temperature and heat generation of a control target such as a heater even in an area where power supply conditions are poor or where a power supply output is unstable even in an area where power supply conditions are good. It is a common problem to be solved that the state can be controlled with high accuracy and high stability.

[0006]

(1) A control system according to the present invention is provided between a power supply and a control target driven by the power supply, and controls an output of the power supply to supply the output to the control target. And controlling the temperature or the state of heat generation, wherein the control is performed based on the output state of the power supply and the temperature control output state related to the temperature or heat generation state of the control target obtained from the temperature controller. It controls the object.

The object to be controlled is not limited to the heater, but may be anything as long as its temperature and the state of heat generation are controlled.

The power supply is not limited to an AC or DC power supply, and any power supply is applicable.

According to the present invention, not only the output state of the temperature control but also the output state of the power supply are included in the control loop. Therefore, even in an area where the power supply situation is unstable, the power supply itself is unstable. Can be used to control the temperature state and the heat generation state of a control target such as a heater with high accuracy and high stability.

[0010] The preferred first of the present invention in the above (1)
As embodiments of the present invention, a switch provided between a power supply and a control target driven by the power supply, a temperature controller that outputs the temperature control output, an output state of the power supply, and a temperature control output And a switch control unit for controlling switching of the switch from the state.

The switch is a thyristor, a MOSFET
, Such as electronic switches, mechanical switches such as ordinary relay contacts, and other switches.

According to the first embodiment, the number of components of the system can be reduced, and the cost can be reduced.

The second preferred embodiment of the present invention in the above (1)
As an embodiment of the present invention, a switch provided between a power supply and a control target driven by the power supply, a temperature controlling the opening and closing of the switch based on an output state of the power supply and a state of the temperature control output. And a controller.

The switch comprises a thyristor, a MOSFET
, Such as electronic switches, mechanical switches such as ordinary relay contacts, and other switches.

According to the second embodiment, the number of components of the system can be reduced, and the cost can be reduced.

(2) The temperature controller of the present invention is provided between a power supply and a control target driven by the power supply, and controls an output of the power supply to supply the output to the control target to generate the temperature or heat. A temperature controller for controlling the state of the power supply, and controlling the control target based on an output state of the power supply and a temperature control output state related to a temperature or a heat generation state of the control target.

The object to be controlled is not limited to the heater, but may be anything as long as its temperature and the state of heat generation are controlled.

The power supply is not limited to an AC or DC power supply, and any power supply is applicable.

According to the present invention, not only the output state of the temperature control but also the output state of the power supply are included in the control loop. Therefore, even in an area where the power supply situation is unstable, the power supply itself is unstable. Can be used to control the temperature state and the heat generation state of a control target such as a heater with high accuracy and high stability.

The output of the power supply described above includes any of voltage, current, and power, and also includes the concept of the amount of heat converted into power by including a time element.

[0021]

Embodiments of the present invention will be described below in detail with reference to the drawings.

A control system according to an embodiment of the present invention will be described with reference to FIGS. 1 is a circuit block diagram of the entire system, FIG. 2 is a circuit diagram of the switch control unit in FIG. 1, and FIG. 3 is a timing chart for explaining the operation.

Referring to FIG. 1, a control system 1 is provided between an AC power supply 2 and a heater 4 to be controlled by the AC power supply 2 and controls a power supply output. The heater 4 is supplied to the heater 4 to control its temperature or the state of heat generation.

Here, the AC power supply 2 differs depending on the country or region, but in this embodiment, it outputs a power supply output having a commercial frequency of 50 Hz or 60 Hz. Further, the heater 4 as an example of the control target is formed of a resistor having various forms such as a plate shape and a coil shape.

The control system 1 has a switch 6, a temperature sensor 8, a temperature controller 10, a voltage sensor 12, and a switch controller 14.

The switch 6 is an electronic switch such as a thyristor or a MOSFET, or a mechanical switch such as a relay contact. The switch 6 is provided between the AC power supply 2 and the heater 4. The power supply output from the AC power supply 2 is supplied to the heater 4 as a heater output by being turned on / off by the switch control signal.

The temperature sensor 8 is disposed in the vicinity of the heater 4 and detects the heat generation temperature of the heater 4, and sends a signal (current heat generation temperature signal) corresponding to the detected heat generation temperature to the temperature controller 10. To be entered.

The temperature controller 10 obtains the data of the current heat generation temperature of the heater 4 and the heater power for the heat generation from the current heat generation temperature signal from the temperature sensor 8, and sets the data of the current heat generation temperature by an external operation. Compared with the data of the set heating temperature, a temperature control output corresponding to the difference between the two heating temperatures, that is, a signal of the target heater power p ₂ ′ is output. The target heater power p ₂ ′ is a shortage or excess power ± △ p corresponding to a deviation from the set heat generation temperature with respect to the current target heater power p ₂ when the current heat generation temperature is obtained.
To correct the _2, a power represented by p ₂ ± △ p _2.

The voltage sensor 12 detects the voltage of the AC power supply 2 and inputs the voltage v to the switch control unit 14 as a power supply output.

The switch control unit 14 determines the power from the reference power to the current power of the AC power supply 2 based on the reference current and power data set internally based on the voltage from the voltage sensor 12. The change is calculated, the difference between the power change and the target heater power from the temperature controller 10 is calculated, and a switch control signal for controlling the opening and closing of the switch 6 is generated based on the difference. Is input to the switch 6, and the switch 6 is turned on. For this reason, the switch control unit 14 may be constituted by a microcomputer. For example, the microcomputer stores the data of the reference voltage, the reference current, and the reference power, and multiplies the actual power obtained by multiplying the voltage v given from the voltage sensor 12 by the reference current to the power supply state of the AC power supply 2 Is determined, the actual power and the reference power are compared, and the difference is defined as a power fluctuation. Of course, there are various methods other than how to obtain the power fluctuation, but in the present embodiment, an example is shown for easy understanding of the description. For example, as another method of obtaining the power fluctuation, not only the voltage but also the current is input from the AC power supply 2 to the microcomputer by the sensor, and the power obtained by multiplying the voltage and the current is compared with the reference power. And instead of multiplying voltage and current,
Power may be obtained from voltage and heater resistance or from current and heater resistance.

Next, a method of obtaining the power fluctuation will be described with reference to FIG.
This will be described in more detail with reference to FIG.

That is, as shown in FIG. 2, the switch controller 14 includes a power fluctuation calculator 14a, a subtractor 14b, and a switch control signal generator 14c. All of these can be implemented by a microcomputer instead of hardware, and can be implemented by software.

The power fluctuation calculator 14a calculates the power fluctuation ±
△ to calculate the p _1. In this calculation, the reference power is p ₁ (= reference voltage v × reference current i), the fluctuating power is p ₁ ′ (= variation voltage v ′ × reference current i), and p ₁ ′ −p ₁ = ± △ p
₁ (+ sign when p ₁ ′ −p ₁ > 0, p ₁ ′ −p ₁ <0
In the case of, the sign of-) is calculated.

Here, the target heater power p ₂ ′ is output from the temperature controller 10. This target heater power p ₂ ′
Is the power currently consumed for driving the heater 4 at p
_{2 If} the current heating temperature of the heater 4 deviates from the set heating temperature, the heater power required to eliminate the deviation, that is, the target difference is set to Δp ₂ . Then,
The target heater power p ₂ ′ is given by p ₂ ± △ p ₂ . Here, the sign “+” indicates that the current heat generation temperature is lower than the set heat generation temperature, and the sign “−” indicates that the current heat generation temperature is higher than the set heat generation temperature.

Then, the subtraction unit 14b performs an operation of p = (p ₂ ± △ p ₂ ) − (± △ p ₁ ) (1). The difference p is used to eliminate the deviation of the current heating temperature of the heater 4 from the set heating temperature by the temperature controller 10 and to eliminate the deviation of the current heating temperature of the heater 4 due to the fluctuation of the power supply. is there.

That is, in the conventional control system, when controlling the heat generation temperature of the heater 4 by the temperature controller 10 to the set heat generation temperature, the power fluctuation ± △ in the equation (1).
p ₁ is assumed to be zero, and therefore, the above equation (1)
Is controlled only by (p ₂ ± △ p ₂ ).

However, in the case of an area where power supply conditions are bad or an unstable power supply, since ± △ p ₁ exists, (p ₂ ±
With the control using only Δp ₂ ), the heater 4 cannot be controlled to the required heating temperature with high accuracy.

On the other hand, in this embodiment, the whole control is performed in consideration of the existence of ± Δp _{1 in} an area where power supply conditions are poor or an unstable power supply.

Then, the switch control signal generator 14c
The switch control signal Ton corresponding to the difference p in the above equation (1)
Is output.

This will be specifically described with reference to FIG.

FIG. 3A is a waveform diagram showing the power supply output input to the switch 6 as a voltage v, FIG. 3B is a diagram showing a switch control signal, and FIG. FIG. 6 is a waveform diagram of a heater output output from the heater 6.

The voltage v shown in FIG.
When it is ₁ , ± △ p ₁ = 0, and the switch 6 is turned on with an on-duty Ton corresponding to (p ₂ ± △ p ₂ ) and turned off with an off-duty Toff within a certain period T. Such a switch control signal is input to the switch 6. Correspondingly, the heater output corresponds to the on-duty Ton as shown by hatching in FIG.
In this state, it is assumed that the current heating temperature of the heater 4 is maintained at the set heating temperature.

Then, when the power supply voltage fluctuates from the reference voltage v ₁ to v ₂ in an area where power supply conditions are bad or disturbance, ±
Δp ₁ exists, and the on-duty is (p ₂ ± △
the on-duty corresponding to p _2), further with on-duty Ton 'to the on-duty that includes power fluctuation ± △ p ₁ comprising in addition to the positive and negative due to the variation of the voltage, closing the switch control signal corresponding to the Input to the container 6.

Thus, even if the power fluctuates, the heater 4
The deviation of the heating temperature from the set value is corrected with high accuracy, and the heating temperature of the heater is maintained at the set heating temperature.

Note that the present invention is not limited to the above-described embodiment, and various modifications and applications can be considered.

(1) In the above embodiment, the temperature controller 1
Although 0 is separate from the switch control unit 14, as shown in FIG. 4, a temperature controller 10a in which the temperature controller 10 and the switch control unit 14 are integrated may be used. Although illustration of the internal configuration of the temperature controller 10a is omitted, the switch controller 14 of FIG. 1 and the temperature controller 10 are integrated, and the operation is described in the same manner as in the above-described embodiment. The description is omitted because it is the same.

(2) In the above embodiment, the temperature controller 1
0 is separate from the switch 6 and the switch control unit 14, but as shown in FIG. 5, the temperature controller 10 and the switch 6
And a temperature controller 10b integrating the switch controller 14
It may be.

Although the illustration of the internal structure of the temperature controller 10b is omitted, the switch 6 and the switch controller 1 shown in FIG.
4 and the temperature controller 10 are integrated, and the description of the operation thereof is the same as that of the above-described embodiment, so that the description thereof will be omitted.

(3) In the above-described embodiment, the output of the AC power supply 2 is input to the switch control unit 14, but a heater output may be input as shown in FIG.

This case will be described. A voltage sensor 18 for detecting the voltage at the heater output;
The output of the voltage sensor 18 is input to the switch control unit 14 as a power supply output signal.

In this case, the switch control unit 14 sets the heater in the variation on-duty Ton 'when the power fluctuates with respect to the average power of the heater output in the reference on-duty Ton period indicated by hatching in FIG. compared to the average power of the output, and the difference by the comparison with the power fluctuation ± △ p _1.

The other parts are the same as those of the above-described embodiment, and the description is omitted.

(4) In the above-described embodiment, the power supply is the AC power supply 2. However, the DC power supply 20 as in the fifth embodiment shown in FIG.

(5) In the above embodiment, the heater 4 is turned on and off. However, the present invention is not limited to this. The heater 4 may be driven by another method.

(6) The application or application field of the above-described embodiment includes not only the above-described semiconductor manufacturing field but also, for example, a heating control system for hot and cold water in a bathtub.

[0056]

As described above, according to the present invention, not only the output state of the temperature control but also the output state of the power supply are included in the control loop. Even if a power supply which itself is unstable is used, the temperature state and the heat generation state of the control target such as the heater can be controlled with high accuracy and high stability.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram of a control system according to an embodiment of the present invention.

FIG. 2 is a circuit diagram of the switch control unit of FIG. 1;

FIG. 3 is a timing chart for explaining the operation of the circuit of FIG. 1;

FIG. 4 is a circuit block diagram of a control system according to another embodiment of the present invention.

FIG. 5 is a circuit block diagram of a control system according to still another embodiment of the present invention.

FIG. 6 is a circuit block diagram of a control system according to still another embodiment of the present invention.

FIG. 7 is a circuit block diagram of a control system according to still another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Control system 2 AC power supply 4 Heater 6 Switch 8 Temperature sensor 10 Temperature controller 12 Voltage sensor 14 Switch control part

 ──────────────────────────────────────────────────続 き Continuing on the front page F term (reference)

Claims (4)

[Claims] A control system is provided between a power supply and a control target driven by the power supply, and controls an output of the power supply to supply the power to the control target to control the temperature or the state of heat generation. A control system for controlling the control target based on an output state of the power supply and a temperature control output state related to a temperature or a heat generation state of the control target obtained from a temperature controller. 2. The control system according to claim 1, wherein a switch provided between a power supply and a control target driven by the power supply, a temperature controller that outputs the temperature control output, and an output of the power supply. A control system, comprising: a switch control unit that controls opening and closing of the switch based on a state and the state of the temperature control output. 3. The control system according to claim 1, wherein a switch provided between a power supply and a control target driven by the power supply, an output state of the power supply, and a state of the temperature control output, A control system, comprising: a temperature controller that controls opening and closing of a switch. 4. A temperature controller provided between a power supply and a control target driven by the power supply, and controls a power supply output to supply the control target and control a temperature or a heat generation state thereof. A temperature controller that controls the control target based on an output state of the power supply and a temperature control output state related to a temperature or a heat generation state of the control target.