KR100962013B1 - Apparatus for controlling temperature induction heating roll and method there of - Google Patents

Abstract

PURPOSE: A temperature controller of an induction heating roll and a method thereof are provided to minimize surface temperature differences of an induction heating roll by controlling output frequency and pulse width according to the surface temperature of the induction heating roll. CONSTITUTION: A heating roll(10) comprises an induction coil(140), a temperature sensor(150), and a slip ring(11). The induction coil is wound in the outer peripheral surface of an inner pipe. The temperature sensor is arranged in the outer peripheral surface of the outer pipe in order to sense the surface temperature of the heating roll. The slip ring is arranged in both sides of the heating roll. The slip ring supplies the pulse length of the output frequency or the output frequency. A controller controls the surface temperature of the heating roll by controlling a driving signal applied to the heating roll.

Description

Temperature control device and temperature control method of induction heating roll {APPARATUS FOR CONTROLLING TEMPERATURE INDUCTION HEATING ROLL AND METHOD THERE OF}

The present invention relates to a temperature control apparatus and a method of an induction heating roll, and in particular, during the stretching process of film, the polishing process of fabric or paper, the surface temperature of the induction heating roll that transfers heat to the workpiece to be maintained uniformly A temperature control device and method for induction heating rolls.

In general, a heating roll is a kind of heater that transfers heat heated in a film stretching process, a fabric or paper polishing process, etc., to a workpiece to perform stretching and polishing while pressing and compressing it with a crimping roll. For this purpose, it is very important to keep the surface temperature of the heating roll uniform.

That is, in the stretching process of the film, the smaller the surface temperature variation of the heating roll, the more uniform film width and thickness quality can be obtained. In the case of the fabric or paper gloss process, the smaller the surface temperature variation of the heating roll, the more flexibility and quality of the texture. And gloss can be obtained.

Thus, in order to maintain the surface temperature of the heating roll uniformly, the surface temperature is controlled by using oil or water as a heat medium in the heating roll, or by varying the output power according to a feedback temperature sensor signal using a commercial frequency. Ceramic heater method or induction heating method is used.

The heat medium method using the oil or water has the disadvantages of leakage and leakage due to high temperature and pressure, and the disadvantage of requiring a separate circulation device, the disadvantage of the performance degradation due to scale, According to the flow state, the temperature deviation of the output side with respect to the surface input side of the heating roll becomes large, which makes it difficult to maintain the surface temperature of the heating roll uniformly.

Since the ceramic heater method requires high power, there is a disadvantage of short circuit, and there is a problem that it is difficult to reduce the temperature deviation due to the imbalance of the output voltage due to the difference of the input voltage of each phase. In particular, the ceramic heater method has a problem that should be replaced by the fire and periodic heater due to cracking and short life.

In addition, the intermediate heat medium method and the internal heater method is that the heat reaching the surface of the heating roll is transferred to the surface only after a predetermined time, so that the heat is deprived to the outside when the output is zero (zero) Since there is no supplemental heat with respect to the deprived heat, there is a problem in that a temperature deviation occurs more greatly.

In addition, the induction heating method has a different temperature distribution depending on the number and length of windings of the induction coil and the spacing between the induction coil and the surface of the heating roll and the output frequency.

In addition, the heating roll has a temperature variation with respect to the setpoint temperature because the temperature rise distribution is different from the frequency characteristic depending on the material (SUS, AL, STEEL) and thickness.

In addition, the induction heating method outputs the output voltage according to the change of the input voltage as it is, and the heating part is locally changed due to the imbalance of the phase voltage of the output voltage according to the change of the input voltage, so that the surface temperature of the heating roll is kept constant. There is a problem that can not be.

An object of the present invention is to detect the surface temperature of the induction heating roll, and output the frequency and the pulse width in accordance with the detected temperature to reduce the surface temperature deviation of the heating roll to maintain the entire surface temperature of the induction heating roll uniformly. .

In addition, the present invention, on the other hand, this induction heating method is to control the surface temperature of the heating roll to obtain a uniform temperature distribution on the surface of the heating roll, by controlling the energy-efficient frequency, energy efficiency compared to conventional commercial frequency control At the same time, it is possible to control the output of the heating roll in response to the change of the surface temperature of the heating roll, and to have a very small setpoint temperature deviation.

In addition, the present invention is to heat from the surface of the heating roll so that the preheating time and the time to reach the temperature to be applied quickly.

In addition, the present invention is intended to extend the life of the induction coil, to remove the surface overheating phenomenon of the heating roll due to the residual heat after the output cut off, occupy less installation space and to prevent environmental pollution.

In order to achieve the above object, the present invention provides a roll main body including an inner pipe having an induction coil wound on an outer circumferential surface thereof, an inner pipe having an inner pipe built therein, and a temperature sensor configured to sense a surface temperature of a heating roll on the outer circumferential surface thereof; And a heating roll formed on both sides of the roll body part, the rotating body including a rotating shaft configured to rotate the roll body part at a constant rotational speed and to supply an output frequency or a pulse width of the output frequency. Blocking unit for blocking the over voltage, over current input from the external power supply terminal for applying power to the induction coil; A noise filter to remove noise of power input from the blocking unit; An electronic switching unit which cuts off the power supply from which the noise is removed from the noise filter unit and the power supply at the time of overload; An AC-DC converter for smoothing the power supply voltage supplied from the electronic switching unit to convert the DC constant current into a constant voltage; A frequency / pulse width converter converting the frequency / pulse width corresponding to the DC constant voltage / constant current converted from the AC-DC converter and outputting the converted frequency to the heating roll; A temperature detector detecting a surface temperature of the heating roll; And a control unit for comparing and controlling the surface temperature and the set temperature of the heating roll detected by the temperature detection unit, and variably controlling the frequency of the frequency / pulse width converter according to the controlled signal. to provide.

The controller increases the output frequency when the surface temperature of the heating roll detected by the temperature detector is higher than the set temperature, and decreases the output frequency when the surface temperature is lower than the set temperature. Characterized in that to maintain.

The control unit compares and determines the surface temperature and the set temperature of the heating roll detected by the temperature detector, and variably controls the pulse width of the frequency / pulse width converter based on the determined temperature.

The control unit decreases the pulse width of the output frequency when the surface temperature detected by the temperature detector is higher than the set temperature, increases the pulse width of the output frequency when the surface temperature is lower than the set temperature, and when the surface temperature and the set temperature are the same. The pulse width of the current output frequency is maintained.

The control unit may detect an overcurrent and an overvoltage from an AC-DC converter to control the constant current and the constant voltage of the AC-DC converter.

In addition, the present invention for realizing the above object,

In the initialization state where constant voltage, constant current, and surface temperature are required to drive the heating roll. Driving a heating roll to a surface temperature while determining whether the constant voltage and the constant current are abnormal;

Detecting a surface temperature of a heating roll driven in the step;

Comparing the surface temperature detected in the step with the set temperature;

In this step, if the surface temperature is higher than the set temperature, the output frequency is increased, if the surface temperature is lower than the set temperature, the output frequency is decreased, and if the surface temperature and the set temperature are the same, maintaining the current output frequency. It is done.

Another invention for realizing the above object is,

In the initialization state where constant voltage, constant current, and surface temperature are required to drive the heating roll. Driving the heating roll to a surface temperature while determining whether the set constant voltage and constant current are abnormal;

Detecting a surface temperature of a heating roll driven in the step;

Comparing the surface temperature detected in the step with the set temperature;

In this step, if the surface temperature is higher than the set temperature, the pulse width of the output frequency is decreased. If the surface temperature is lower than the set temperature, the pulse width of the output frequency is increased. If the surface temperature and the set temperature are the same, the pulse of the current output frequency is equal. Characterized in that the step consists of maintaining the width.

Another invention for realizing the above object is,

In the initialization state where constant voltage, constant current, and surface temperature are required to drive the heating roll. Selecting any one of a pulse width control of a frequency or an output frequency of driving the heating roll;

Driving a heating roll while determining whether there is an abnormality of the constant voltage and the constant current set according to the control selected in the step;

In the step of selecting frequency control, detecting the surface temperature of the driving heating roll and comparing the detected surface temperature with a set temperature;

Controlling the output frequency to increase if the surface temperature is higher than the set temperature, decrease the output frequency if the surface temperature is lower than the set temperature, and maintain the current output frequency if the surface temperature is equal to the set temperature;

In the step of selecting pulse width control, detecting a surface temperature of a driving heating roll and comparing the detected surface temperature with a set temperature;

In this step, if the surface temperature is higher than the set temperature, the pulse width of the output frequency is decreased. If the surface temperature is lower than the set temperature, the pulse width of the output frequency is increased. If the surface temperature and the set temperature are the same, the pulse of the current output frequency is equal. Characterized in that the step consisting of maintaining the width.

Therefore, according to the present invention, when driving the heating roll in an induction heating method, by supplying the pulse width of the output frequency or output frequency to the heating roll to drive the heating, the surface temperature and the set temperature and detected by detecting the surface temperature of the heating roll In comparison, if the detected surface temperature is higher than the set temperature, the output frequency increases and the pulse width of the output frequency decreases. If the detected surface temperature is lower than the set temperature, the output frequency decreases and the output frequency decreases. By controlling the pulse width to increase, the entire surface temperature of the heating roll is evenly heated to reduce the overall surface temperature deviation, thereby providing the effect of maintaining the surface temperature of the heating roll uniformly.

Moreover, according to this invention, since it heats from the surface of a heating roll, there exists an effect that preheating time and temperature arrival time can be applied quickly.

In addition, according to the present invention, it is possible to extend the life of the induction coil, to remove the surface overheating phenomenon of the heating roll due to the residual heat after the output cut off, occupy a small installation space and can prevent the environmental pollution.

Figure 1a and 1b is a schematic block diagram of a temperature control device of the induction heating roll of the present invention
Figure 2 is a detailed block diagram of the temperature control device of the present invention induction heating roll
Figure 3 is a frequency control flowchart for the temperature control method of the induction heating roll of the present invention
Figure 4 is a pulse width modulation control flow chart for the temperature control method of the induction heating roll of the present invention
Figure 5 is a frequency and pulse width modulation control flowchart for the temperature control method of the induction heating roll of the present invention

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIGS. 1A and 1B, the present invention comprises a heating roll 10 and a controller 20.

The heating roll 10 is configured to rotate on a rotating shaft in a cylindrical shape and transmits heat to a workpiece while driving heat at a frequency or pulse width supplied thereto, and an induction coil as a heating medium in the heating roll 10. 140, a temperature sensor 150 for detecting the surface temperature is provided, both sides of the heating roll 10, the slip ring 11 for smoothly inducing rotation and supplying the pulse width of the output frequency or the output frequency (11) ) Is configured.

The induction coil 140 is wound on the outer circumferential surface of the heating roll 10, and the inner pipe 120 and the inner pipe 120 configured with a power line for applying power to the induction coil 140 and a temperature detection line are provided. It is built-in, formed on both sides of the roll body portion 102 and the roll body portion 102 including an outer pipe 110 is configured with a temperature sensor 150 for sensing the surface temperature of the heating roll 10 on the outer peripheral surface The rotation of the roll body 102 at a constant rotational speed, the bearing 132 for supporting the rotation of the heating roll 10 on the outer peripheral surface, and the pulse width of the output frequency or output frequency on the surface of the heating roll 10 Slip ring 11 for supplying is configured to include a rotating shaft 130 is configured.

The controller 20 controls the driving signal applied to the heating roll 10 to control the surface temperature of the heating roll 10.

As shown in FIG. 2, the controller 20 includes a cutoff unit 21, a noise filter unit 22, an electronic switch unit 23, an AC-DC converter 24, and a frequency / pulse width converter 25. ), A temperature detector 26, and a controller 27.

The cut-off unit 21 is connected to an external power source such as a power line for applying power to the induction coil 140, a temperature detection line, etc., and comprises a fuse and a switch to cut off the power when an overvoltage or overcurrent is input from the external power source. do.

The noise filter unit 22 is connected to the blocking unit 21 to remove noise contained in the power supply voltage input from the blocking unit 21, and the noise filter unit 22 is constituted by a coil and a condenser. do.

The electronic switch 23 is connected to the noise filter 22 to supply a smooth constant voltage and a constant current from the noise filter 22, and cut off a power voltage input when an overload occurs, and the electronic switch 23 ) Consists of magnetic contactor and overload relay.

The AC-DC converter 24 is connected to the electronic switch 23 to smooth the constant voltage constant current input from the electronic switch 23 to convert the DC constant current and the constant voltage, the AC-DC converter 24 It consists of a constant voltage circuit and a constant current circuit.

The frequency / pulse width converter 25 is connected to the AC-DC converter 25 to convert the DC constant voltage and the constant current input from the AC-DC converter 24 into the corresponding frequency / pulse width. The frequency / pulse width converter 25 generates and outputs a pulse width signal of an output frequency or an output frequency according to the input constant voltage and the constant current.

The frequency / pulse width converter 25 is composed of an insulated gate bipolar transistor (IGBT) or a field effect transistor (FET) which is a high speed switching element.

 The temperature detector 26 is connected to a temperature sensor of the heating roll 10 to be detected by the temperature sensor to detect the surface temperature of the heating roll 10.

The control unit 27 compares the surface temperature of the heating roll 10 detected by the temperature detection unit 26 with the set temperature, and outputs the determined signal to the frequency / pulse width conversion unit 25 to output the frequency / The pulse width is variably controlled and connected to the AC-DC converter 24 to detect and control overvoltage and overcurrent of the AC-DC converter 40.

The control unit 27 is a microprocessor for frequency / pulse width control, and an overvoltage, overcurrent, constant voltage, constant current, temperature, and frequency required for driving the heating roll 70. It consists of a memory for storing pulse width data and a self-diagnosis algorithm.

According to the present invention configured as described above, the overvoltage and overcurrent are cut off through the power supply voltage inputted from the external power supply terminal through the blocking unit 21, the noise filter unit 22, and the electronic switching unit 23, and removes the inflow noise. And input to the AC-DC converter 24 while blocking the overload.

The AC-DC converter 24 smoothes the voltage and current input from the electronic switch 23 into a DC constant voltage and a constant current through a constant voltage circuit and a constant current circuit, and inputs the same to the frequency / pulse width converter 25.

The frequency / pulse width converter 25 is configured to vary the pulse width of the corresponding output frequency / output frequency with respect to the DC constant voltage and the constant current input by switching through an insulation gate bipolar transistor (IGBT) or a field effect transistor (FET). By supplying the pulse width of the variable output frequency / output frequency to the induction coil of the heating roll 10, the induction coil is the heating roll by the vortex hand according to the pulse width of the variable output frequency / output frequency supplied ( The surface of 10) is heated.

Here, the induction coil of the heating roll 10 is the resistance (inductive reactance) X _L = 2πfL, and Joule heat Q = V ² / Rt [J] = I ² Rt. That is, since the temperature (heat) is inversely proportional to the resistance, and the current flowing on the surface of the heating roll 10 is proportional to the temperature, the higher the frequency, the more the resistance component (X _L ) applied to the induction coil increases and the heating roll 10 On the other hand, the current flowing on the surface decreases and the temperature decreases. On the other hand, as the frequency decreases, the resistance component X _{L applied} to the induction coil decreases, and the current flowing on the surface of the heating roll 10 increases to increase the temperature. .

In addition, by controlling the current flowing through the induction coil of the heating roll 10 with a pulse width to control the loss of eddy current and hysteresis flowing on the surface of the heating roll 10, in this case also the heating roll 10 Since the current flowing on the surface of the) and the temperature is proportional to each other, as the pulse width decreases, the resistance component (X _L ) applied to the induction coil increases so that the current flowing on the surface of the heating roll 10 decreases to decrease the temperature. On the other hand, as the pulse width increases, the resistance component X _{L applied} to the induction coil decreases, so that the current flowing on the surface of the heating roll 10 increases, and the temperature increases.

After heating the heating roll 10 by varying the frequency or pulse width supplied to the heating roll 10 as described above, the workpiece to be in contact with the heating roll 10 is stretched and polished while being pressed with a pressing roll. At this time, the surface temperature of the heating roll 10 is uniformly maintained in order to improve the stretching and polishing process of the workpiece.

3 is a frequency control flowchart of the temperature control method of the induction heating roll of the present invention, in order to make the surface temperature of the heating roll 10 uniform, the control unit 27 requires a constant voltage for driving the heating roll 10. In the initialization state in which the constant current and the surface temperature are set, it is determined whether the set constant voltage and the constant current are abnormal through the AC / DC converter 24, and the frequency / pulse width converter 25 is controlled to set the constant voltage, The output frequency corresponding to the constant current is output to the induction coil of the heating roll 10 to heat the surface of the heating roll 10 (S31).

Subsequently, the control unit 27 detects the present surface temperature of the heating roll 10 from the temperature sensor provided in the heating roll 10 through the temperature detecting unit 26 (S32), and the detected surface temperature is higher than the set temperature. It is determined whether or not the high (S33).

At this time, if the detected surface temperature is higher than the set temperature, the induction reactance of the induction coil of the heating roll 10 becomes X _L = 2πfL, and the main heat train Q = V2 / Rt [J], so that the temperature for the induction coil is resistance. Inversely proportional to the current flowing on the surface of the heating roll 10 is proportional to the temperature, the control unit 27 in order to lower the surface temperature of the current heating roll 10 to the set temperature, frequency / pulse width conversion unit A control signal for increasing the output frequency is output to 25, and the frequency / pulse width converter 25 outputs the increased output frequency to the induction coil of the heating roll 10 to increase the resistance of the induction coil. And the current decreases to lower the surface temperature proportional to the current (S34).

On the other hand, the control unit 27 determines whether the detected surface temperature is lower than the set temperature (S35).

At this time, if the detected surface temperature is lower than the set temperature, the control unit 27 decreases the output frequency to the frequency / pulse width converter 25 to increase the surface temperature of the current heating roll 10 to the set temperature. The frequency / pulse width converter 25 outputs the reduced output frequency to the induction coil of the heating roll 10 so that the resistance of the induction coil decreases and the current increases to increase the surface temperature in proportion to the current. Will increase (S36).

On the other hand, the controller 27 determines whether the detected surface temperature is equal to the set temperature (S37). At this time, if the detected surface temperature is equal to the set temperature, the controller 27 determines the frequency / pulse width converter ( The control signal for maintaining the current output frequency is output to 25) to maintain the surface temperature of the heating roll 10 at the current output frequency (S38).

In this way, the output temperature is controlled at both ends of the induction coil according to the surface temperature of the heating roll 10 to control the surface temperature, so that the temperature deviation can be very small on the surface of the heating roll 10, and the set temperature is reached at the initial startup. The shorter time allows for faster and more uniform temperature response.

4 is a pulse width modulation control flow chart for the temperature control method of the induction heating roll of the present invention. In the control unit 27, in order to make the surface temperature of the heater roll 10 uniform, the driving roll 10 is driven. In the initialization state in which the necessary constant voltage, constant current, and surface temperature are set, the AC / DC converter 24 is controlled to determine whether the set constant voltage and constant current are abnormal, and the frequency / pulse width converter 25 is The pulse width is converted into the pulse width for the output frequency corresponding to the set constant voltage and the constant current, and the converted pulse width is output to the induction coil of the heating roll 10 to heat the surface of the heating roll 10 (S41).

Subsequently, the control unit 27 detects the present surface temperature of the heating roll 10 from the temperature sensor provided in the heating roll 10 through the temperature detecting unit 26 (S42), and the detected surface temperature is higher than the set temperature. It is determined whether or not the high (S43).

At this time, if the detected surface temperature is higher than the set temperature, the temperature for the induction coil is inversely proportional to the resistance, and the current flowing on the surface of the heating roll 10 is proportional to the temperature, so that the control unit 27 includes a frequency / pulse width conversion unit. A control signal for reducing the pulse width of the output frequency is output to 25, and the frequency / pulse width converter 25 outputs the reduced pulse width of the output frequency to the induction coil of the heating roll 10. The resistance of the induction coil increases and the current decreases to lower the surface temperature proportional to the current (S44).

On the other hand, the control unit 27 determines whether the detected surface temperature is lower than the set temperature (step 45). At this time, if the detected surface temperature is lower than the set temperature, the control unit 27 converts the frequency / pulse width. The control unit 25 outputs a control signal that increases the pulse width of the output frequency to decrease the resistance of the induction coil of the heating roll 10 and increases the current to increase the surface temperature proportional to the current (S46). ).

On the other hand, the control unit 27 determines whether the detected surface temperature is equal to the set temperature (S47). At this time, if the detected surface temperature is equal to the set temperature, the control unit 27 uses the frequency / pulse width converting unit ( A control signal for maintaining the pulse width of the current output frequency is output to 25) to maintain the surface temperature of the heating roll 10 at the pulse width of the current output frequency from the frequency / pulse width converter 25 (S48). .

As such, by controlling the surface temperature rise and fall of the heating roll 10 to the pulse width of the output frequency, the temperature deviation caused by the distance between the induction coil and the surface of the heating roll 10 can be reduced, so that the set temperature reaching time is short. It will be able to maintain a uniform temperature quickly.

FIG. 5 is a flowchart illustrating a frequency and pulse width control of a temperature control method of an induction heating roll according to the present invention. In the control unit 27, the heating roll 10 is driven in order to make the surface temperature of the heater roll 10 uniform. In the initialization state in which the constant voltage, the constant current, and the surface temperature required are set, the control unit 27 selects whether to control the heating roll 10 by frequency or pulse width modulation control (S51).

At this time, when the frequency control is selected (S52), as described above, the frequency of the heating roll 10 to the set temperature in a series of frequency control (S31 ~ 38) step (S30) shown in FIG. Heating is variable.

On the other hand, when the pulse width modulation control is selected (S53), as described above, the heating roll 10 is set to the set temperature in a series of pulse width control steps (S41 to 48) (S40) shown in FIG. The heating is performed while the pulse width is changed to suit.

10; Heating roll 20; Controller
21; Blocking part 22; Noise filter section
23; Electronic switch 24; AC-DC converter
25; Frequency / pulse width converter 26; Temperature detector
27; Control

Claims (8)

An inner pipe in which an induction coil is wound on an outer circumferential surface thereof, and an inner pipe having an inner pipe, and a roll body part including an outer pipe having a temperature sensor configured to detect a surface temperature of a heating roll on an outer circumferential surface thereof; And a heating roll formed on both sides of the roll body part, the rotating body including a rotating shaft configured to rotate the roll body part at a constant rotational speed and to supply an output frequency or a pulse width of the output frequency.
Blocking unit for blocking the over voltage, over current input from the external power supply terminal for applying power to the induction coil;
A noise filter to remove noise of power input from the blocking unit;
An electronic switching unit which cuts off the power supply from which the noise is removed from the noise filter unit and the power supply at the time of overload;
An AC-DC converter for smoothing the power supply voltage supplied from the electronic switching unit to convert the DC constant current into a constant voltage;
A frequency / pulse width converter converting the frequency / pulse width corresponding to the DC constant voltage / constant current converted from the AC-DC converter and outputting the converted frequency to the heating roll;
A temperature detector detecting a surface temperature of the heating roll; And
And a control unit for comparing and controlling the surface temperature and the set temperature of the heating roll detected by the temperature detection unit, and variably controlling the frequency of the frequency / pulse width converter according to the controlled signal. controller.
The method of claim 1,
The controller increases the output frequency when the surface temperature of the heating roll detected by the temperature detector is higher than the set temperature, and decreases the output frequency when the surface temperature is lower than the set temperature. Temperature control device of the induction heating roll, characterized in that to maintain. The method of claim 1,
The control unit is a temperature control device of the induction heating roll, characterized in that the comparison control of the surface temperature and the set temperature of the heating roll, and variably control the pulse width of the output frequency of the frequency / pulse width converter according to the controlled signal. The method of claim 1,
The control unit decreases the pulse width of the output frequency when the surface temperature detected by the temperature detector is higher than the set temperature, increases the pulse width of the output frequency when the surface temperature is lower than the set temperature, and when the surface temperature and the set temperature are the same. Temperature control device of the induction heating roll, characterized in that to maintain the pulse width of the current output frequency. The method of claim 1,
The controller controls the constant current and the constant voltage of the AC-DC converter by detecting an overcurrent and an overvoltage from the AC-DC converter. In the initialization state where constant voltage, constant current, and surface temperature are required to drive the heating roll. Driving a heating roll to a set surface temperature while determining whether the constant voltage and the constant current are abnormal;
Detecting a surface temperature of a heating roll driven in the step;
Comparing the surface temperature detected in the step with the set temperature;
In this step, if the surface temperature is higher than the set temperature, the output frequency is increased, If the surface temperature is lower than the set temperature, the output frequency is reduced, and if the surface temperature and the set temperature is the same, including the step of controlling to maintain the current output frequency Temperature control method of induction heating roll. In the initialization state where constant voltage, constant current, and surface temperature are required to drive the heating roll. Driving a heating roll to a set surface temperature while determining whether the set constant voltage and constant current are abnormal;
Detecting a surface temperature of a heating roll driven in the step;
Comparing the surface temperature detected in the step with the set temperature;
In this step, if the surface temperature is higher than the set temperature, the pulse width of the output frequency is decreased. If the surface temperature is lower than the set temperature, the pulse width of the output frequency is increased. If the surface temperature and the set temperature are the same, the pulse of the current output frequency is equal. A method of temperature control of an induction heating roll comprising controlling to maintain a width. In the initialization state where constant voltage, constant current, and surface temperature are required to drive the heating roll. Selecting one of an output frequency or a pulse width control of an output frequency for driving the heating roll;
Driving a heating roll while determining whether there is an abnormality of the constant voltage and the constant current set according to the control selected in the step;
In the step of selecting frequency control, detecting the surface temperature of the driving heating roll and comparing the detected surface temperature with a set temperature;
Controlling the output frequency to increase if the surface temperature is higher than the set temperature, decrease the output frequency if the surface temperature is lower than the set temperature, and maintain the current output frequency if the surface temperature is equal to the set temperature;
In the step of selecting pulse width control, detecting a surface temperature of a driving heating roll and comparing the detected surface temperature with a set temperature;
In this step, if the surface temperature is higher than the set temperature, the pulse width of the output frequency is decreased. If the surface temperature is lower than the set temperature, the pulse width of the output frequency is increased. If the surface temperature and the set temperature are the same, the pulse of the current output frequency is equal. A method of temperature control of an induction heating roll comprising controlling to maintain a width.

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