JP2013040695A - Apparatus and device for controlling vapor temperature - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for controlling vapor temperature and a method for controlling vapor temperature that achieve a control system resistant to disturbance while compensating dead time.SOLUTION: According to an embodiment, the apparatus for controlling a vapor temperature includes: a dead time compensation unit for outputting a signal for compensating the dead time generated at least in an heat exchanger based on a signal indicating an actual measurement value of an inlet temperature of the heat generator; a first control unit for outputting a first control signal to equalize an outlet temperature of the heat generator with a target value based on a value after correcting an actual measurement value of the outlet temperature of the heat exchanger according to a signal output from a dead time compensation circuit, and the target value of the outlet temperature of the heat exchanger; and a second control unit for supplying a second control signal to a control valve so that the inlet temperature of the heat exchanger is equalized to a target value after the correction based on the target value after correcting the target value of the inlet temperature of the heat generator according to the first control signal.

Description

  Embodiments described herein relate generally to a steam temperature control device and a steam temperature control method.

  A boiler facility in a thermal power plant or the like is provided with a steam temperature control device for controlling the steam temperature at the outlet or inlet of a heat exchanger such as a superheater.

  For example, when controlling the main steam in a thermal power plant or the like with a steam temperature control device, the heat exchange is performed by adjusting the amount of water injected into the desuperheater in the previous stage of the target heat exchanger with a control valve. The temperature of the steam after passing through the vessel is kept constant.

  In such a control system, a dead time (time required for the output value to start responding when the input value changes) or a time delay (after the output value starts to respond) as shown in FIG. 9 in the heat exchanger. Since it takes time until the change is completed, control becomes difficult. In order to remove such time delay elements such as dead time, a Smith method is generally adopted in which the output of the controller is fed back to the input side of the controller through a Smith Predictor.

JP-A-7-110108 JP-A-5-87307

  The existing Smith method is effective as a method for removing the dead time element, but is weak against disturbance generated in the plant, for example, between the control valve and the heat exchanger inlet. That is, when a disturbance occurs in the plant, there is a problem that it is difficult to reflect the influence of the disturbance in the control.

  The problem to be solved by the present invention is to provide a steam temperature control device and a steam temperature control method that realize a control system that is resistant to disturbance while compensating for dead time.

  The steam temperature control device of the embodiment includes a heat exchanger that superheats the supplied steam, a temperature reducer that reduces the temperature of the steam supplied to the heat exchanger with a refrigerant, and a refrigerant that is supplied to the temperature reducer. In a steam temperature control device applied to a plant having a boiler facility having a control valve for adjusting the amount of the heat generated at least in the heat exchanger based on a signal indicating an actual measured value of the inlet temperature of the heat exchanger A dead time compensation means for outputting a signal for compensating the dead time, a value obtained by correcting an actual measured value of the outlet temperature of the heat exchanger according to a signal outputted from the dead time compensation circuit, and the heat First control means for outputting a first control signal for causing the outlet temperature of the heat exchanger to be equal to the target value based on a target value of the outlet temperature of the exchanger, and an inlet of the heat exchanger Measured value of temperature and the heat exchanger Second control for making the inlet temperature of the heat exchanger equal to the corrected target value based on the target value after correcting the target value of the inlet temperature according to the first control signal And second control means for supplying a signal to the control valve.

  ADVANTAGE OF THE INVENTION According to this invention, the steam temperature control apparatus and steam temperature control method which implement | achieve a control system strong against disturbance, compensating for dead time can be provided.

The block diagram which shows schematic structure of the boiler equipment common to each embodiment. The block diagram which shows an example of the structure of the steam temperature control apparatus which concerns on 1st Embodiment, and its control object periphery. The conceptual diagram which shows the function structure of the dead time compensation circuit shown in FIG. The block diagram which shows an example of the structure of the steam temperature control apparatus which concerns on 2nd Embodiment, and its control object periphery. FIG. 5 is a conceptual diagram showing a functional configuration of a dead time / delay time compensation circuit shown in FIG. 4. The block diagram which shows an example of the structure of the steam temperature control apparatus which concerns on 3rd Embodiment, and its control object periphery. The block diagram which shows an example of the structure of the steam temperature control apparatus which concerns on 4th Embodiment, and its control object periphery. The block diagram which shows an example of the structure of the steam temperature control apparatus which concerns on 5th Embodiment, and its control object periphery. The conceptual diagram for demonstrating a dead time and delay time.

  Hereinafter, embodiments will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a schematic configuration of boiler equipment common to the embodiments.

  A boiler facility 1 shown in FIG. 1 is provided in a thermal power plant or the like. As main components, a boiler 2, a steam drum 3, an evaporator 4, a heat exchanger (first heat exchanger) 5, A heat exchanger (second heat exchanger) 6, a temperature reducer 7, a control valve 8, a deaerator 9, a feed water pump 10, a economizer 11, and a steam temperature controller 20 are provided. The evaporator 4, the heat exchanger 5, the heat exchanger 6, and the economizer 11 are accommodated in the boiler 2.

  Water is taken into the boiler facility 1 from the outside, and this water is deaerated by the deaerator 9 and then supplied to the boiler 2 by the feed water pump 10, and the temperature is raised by the economizer 11, It enters the drum 3 and becomes vapor by the evaporator 4. The steam is superheated from the steam drum 3 through the heat exchanger 5, is reduced in temperature by the temperature reducer 7, is further superheated again through the heat exchanger 6, and the superheated steam is converted into a steam turbine (not shown). )).

  On the other hand, water as a refrigerant is supplied to the temperature reducer 7 via a regulating valve 8 that regulates the amount of water such as a spray valve. The opening degree of the control valve 8 is controlled by the steam temperature control device 20. The steam temperature control device 20 calculates the opening command value of the control valve 8 so that the temperature of the steam at the outlet of the heat exchanger 6 to be controlled is equal to the target temperature, and the command value is sent to the control valve 8. The amount of water supplied to the temperature reducer 7 is adjusted by outputting.

  Hereinafter, the detail of the said steam temperature control apparatus 20 is demonstrated through each embodiment.

(First embodiment)
The first embodiment will be described with reference to FIGS. 2 and 3.

  FIG. 2 is a block diagram showing an example of the configuration of the steam temperature control device 20 according to the first embodiment and the periphery of the control target.

  The steam temperature control apparatus 20 according to the first embodiment includes, as main components, a dead time compensation circuit 21, a correction unit 22, an outlet temperature target value setting unit 23, and an outlet temperature control unit (first control unit) 24. , An inlet temperature target value setting unit 25, a correction unit 26, and an inlet temperature control unit (second control unit) 27. The inlet A of the heat exchanger 6 is provided with a temperature detector 28 that detects the temperature of steam at the inlet of the heat exchanger 6 (hereinafter referred to as “inlet temperature”). B is provided with a temperature detector 29 for detecting the temperature of steam at the outlet of the heat exchanger 6 (hereinafter referred to as “outlet temperature”).

  The dead time compensation circuit 21 receives a signal indicating an actual measured value of the inlet temperature of the heat exchanger 6 detected by the temperature detector 28, and compensates at least a dead time generated in the heat exchanger 6 based on this signal. For this purpose, a dead time compensation signal is output. The dead time compensation circuit 21 may be realized using, for example, a Smith predictor.

  The correction unit 22 inputs a signal indicating the actual value of the outlet temperature of the heat exchanger 6 detected by the temperature detector 29 and corrects this signal according to the dead time compensation signal output from the dead time compensation circuit 21. In other words, the dead time element is removed from the signal indicating the actual measured value of the outlet temperature, and the corrected value is supplied to the outlet temperature control unit 24. The correction unit 22 may be provided in the dead time compensation circuit 21 or may be provided in the outlet temperature control unit 24.

  The outlet temperature target value setting unit 23 sets a target value for the outlet temperature of the heat exchanger 6 and outputs the set target value for the outlet temperature.

  The outlet temperature control unit 24 corrects the actual value of the outlet temperature of the heat exchanger 6 detected by the temperature detector 29 according to the value output from the dead time compensation circuit 21, and the outlet temperature target value. Based on the target value of the outlet temperature of the heat exchanger 6 output from the setting unit 23, feedback control such as PID control is performed to make the outlet temperature of the heat exchanger 6 equal to the target value. A control signal is output.

  The inlet temperature target value setting unit 25 sets a target value of the inlet temperature of the heat exchanger 6 based on a plant index such as a load command value and outputs the set inlet temperature target value.

  The correction unit 26 corrects the target value of the inlet temperature of the heat exchanger 6 output from the inlet temperature target value setting unit 25 in accordance with the first control signal output from the outlet temperature control unit 24. .

  The inlet temperature control unit 27 performs feedback control such as PID control based on the actual measured value of the inlet temperature detected by the temperature detector 28 and the target value of the inlet temperature corrected by the correction unit 26, and performs heat exchange. A second control signal for making the inlet temperature of the vessel 6 equal to the corrected target value is supplied to the control valve 8 as an opening command value signal of the control valve 8.

  As can be seen from the above description, the steam temperature control device 20 has a configuration in which the outlet temperature control unit 24 controls the outlet temperature of the heat exchanger 6 based on the actual measurement value of the temperature detector 29 as the upper control, and the lower order. In which the inlet temperature control unit 27 controls the inlet temperature of the heat exchanger 6 based on the actually measured value of the temperature detector 28. In the example of FIG. 2, only the configuration corresponding to the control of one heat exchanger (heat exchanger 6) is shown, but similar control is performed for each of a plurality of heat exchangers connected in series (not shown). May be configured in parallel. For example, a configuration in which circuits for taking out actual measured values of temperatures from the inlet / outlet of each heat exchanger are connected in cascade may be applied.

  During operation of the plant, a disturbance occurs between the control valve 8 and the heat exchanger 6 inlet, for example. The actual measured value of the inlet temperature detected by the temperature detector 28 is transmitted to the dead time compensation circuit 21 in a form affected by such disturbance. In the dead time compensation circuit 21, a dead time compensation element is calculated based on the measured value of the inlet temperature including the influence of disturbance, and the dead time compensation circuit 21 reflects a dead time compensation signal reflecting the influence of the disturbance. The signal indicating the measured value of the outlet temperature is corrected by the dead time compensation signal that is transmitted to the correcting unit 22 and the influence of the disturbance is reflected from the correcting unit 22 (that is, the signal indicating that the measured value of the outlet temperature is wasted) The signal from which the time element is removed is transmitted to the outlet temperature control unit 24. In the outlet temperature control unit 24 and the inlet temperature control unit 27, control is performed based on a feedback signal in which the influence of disturbance is reflected, so that a control system that compensates not only for dead time but also for disturbance is realized. Is done.

  FIG. 3 is a conceptual diagram showing a functional configuration of the dead time compensation circuit 21 shown in FIG.

  The control unit 30 is an element that comprehensively represents the elements 24-27 in FIG. In the heat exchanger 6 as an actual machine, there are various delay time elements including a primary delay element 32 and a secondary delay element 33 in addition to the dead time element 31. Here, illustration of a higher-order delay time element of the third order or higher is omitted.

  On the other hand, the dead time compensation circuit 21 is a dead time element 31 ′ as a calculation model for predicting a dead time element 31, a first-order lag element 32, and a second-order lag element 33 in the heat exchanger 6 as an actual machine. An element 32 ′ and a second-order lag element 33 ′ are included. Here, for simplification of description, description of the third and higher order delay time elements is omitted. The correction unit 22 may be provided in the dead time compensation circuit 21 or may be provided in the control unit 30.

  The dead time element, the first-order lag element, and the second-order lag element are, for example, transfer function Exp (−Ls), G1 (s) = G1 × 1 / (1 + T1s), G2 (s) = G2 × 1 / It can be expressed as (1 + T2s) (L: dead time, T1, T2: time constant, G1, G2: gain). Further, various control parameters (L: dead time, T1, T2: time constant, G1, G2: gain) in the waste element 31 ′, the first-order delay element 32 ′, and the second-order delay element 33 ′ are variable, and are appropriately determined. Can be adjusted by changing the settings.

  The dead time compensation circuit 21 receives from the inlet A of the heat exchanger 6 a signal indicating an actually measured value of the inlet temperature that is affected by the disturbance. Multiply the element and finally multiply the dead time element. Here, the calculation is performed in the order of the secondary delay element 33 ', the primary delay element 32', and the dead time element 31 '. Here, the dead time compensation circuit 21 temporarily stores the calculation result before multiplication of the dead time element 31 ′ in a predetermined storage area (not shown), and the calculation result after multiplication of the dead time element 31 ′. Therefore, the calculation unit 34 subtracts the calculation result before the dead time element 31 ′ is multiplied, and outputs the result as a dead time compensation signal. The dead time compensation signal reflects the influence of the above-described disturbance.

  Thereby, in the correction unit 22, the signal indicating the actual value of the outlet temperature obtained from the outlet B of the heat exchanger 6 is corrected by the dead time compensation signal in which the influence of the disturbance is reflected, and is fed back to the control unit 30. Is done.

  According to the first embodiment, the dead time compensation circuit 21 performs a dead time compensation by inputting a signal indicating the measured value of the inlet temperature affected by the disturbance from the inlet A of the heat exchanger 6. Because of this configuration, it is not necessary to separately install a device for disturbance compensation, and it is possible to perform not only dead time compensation but also disturbance compensation without increasing costs.

  Further, since it is possible to remove the dead time element and the disturbance time, for example, even when the control parameter value of the outlet temperature control unit 24 is set large (strongly), the stability at the time of plant stabilization is maintained. In addition, it is possible to improve responsiveness / follow-up performance to plant load fluctuations.

(Second Embodiment)
The second embodiment will be described with reference to FIGS. 4 and 5.

  FIG. 4 is a block diagram illustrating an example of the configuration of the steam temperature control device 20 according to the second embodiment and the periphery of the control target. Elements that are the same as those in FIG. 2 are given the same reference numerals, and redundant descriptions are omitted.

  The steam temperature control device 20 shown in FIG. 4 has a configuration in which a dead time / delay time compensation circuit 21A is provided instead of the dead time compensation circuit 21 in the configuration of the steam temperature control device 20 shown in FIG. .

  The dead time / delay time compensation circuit 21A is obtained by adding a function for compensating for the delay time generated in the heat exchanger 6 to the dead time compensation circuit 21 described above, and only the dead time generated in the heat exchanger 6 is provided. In addition, a dead time / delay time compensation signal for compensating for the delay time is also output.

  FIG. 5 is a conceptual diagram showing a functional configuration of the dead time / delay time compensation circuit 21A shown in FIG. In addition, the same code | symbol is attached | subjected to the element which is common in FIG. 3, and the overlapping description is abbreviate | omitted.

  The dead time / delay time compensation circuit 21A shown in FIG. 5 has a configuration in which the arrangement position of the primary delay element 32 'is changed in the configuration of the dead time compensation circuit 21 shown in FIG.

  The dead time / delay time compensation circuit 21A inputs from the inlet A of the heat exchanger 6 a signal indicating an actual measured value of the inlet temperature affected by the disturbance, and for example, from a delay element having a high order with respect to this input signal. Multiply each delay element in turn, and finally a dead time element. Here, the calculation is performed in the order of the secondary delay element 33 ', the primary delay element 32', and the dead time element 31 '. Here, the dead time / delay time compensation circuit 21A temporarily stores the calculation result before multiplication of the primary delay element 32 ′ and the dead time element 31 ′ in a predetermined storage area (not shown). From the calculation result after multiplying the delay element 32 ′ and the dead time element 31 ′, the calculation result before the multiplication by the primary delay element 32 ′ and the dead time element 31 ′ is subtracted in the calculation unit 34, and the result is used as a dead time.・ Output as delay time compensation signal. The dead time / delay time compensation signal reflects the influence of the aforementioned disturbance.

  Thereby, in the correction part 22, the signal which shows the measured value of the exit temperature obtained from the exit B of the heat exchanger 6 is corrected by the dead time / delay time compensation signal in which the influence of the disturbance is reflected, and the control part Is fed back to 30.

  In the example of FIG. 5, the case where the primary delay element 32 ′ is connected in series to the dead time element 31 ′ is illustrated, but in addition to this, the secondary delay element 33 ′ is further connected in series. You may comprise. Thereby, in addition to the primary delay element 32 ', the secondary delay element 33' can be compensated. In addition, a higher-order delay time element equal to or greater than the third-order delay may be substituted by directly connecting a plurality of first-order delay elements 32 ', for example.

  Further, when the process is identified taking into account, for example, a dead time element and a first to fourth delay element, a dead time / delay time compensation circuit is used for the dead time element and the first to second delay elements, for example. 21A may be compensated, and the remaining third-order to fourth-order lag elements may be compensated by control of the outlet temperature control unit 24 (PID control or the like). In this case, since the order handled on the dead time / delay time compensation circuit 21A side is the same as the order handled on the outlet temperature control unit 24 side, it is easy to determine the control parameter.

  According to the second embodiment, in addition to the effects obtained in the first embodiment, the delay time in the heat exchanger 6 can also be compensated.

(Third embodiment)
The third embodiment will be described with reference to FIG.

  FIG. 6 is a block diagram illustrating an example of a configuration around the steam temperature control device 20 according to the third embodiment and its control target. In addition, the same code | symbol is attached | subjected to the element which is common in FIG. 4, and the overlapping description is abbreviate | omitted.

  The steam temperature control device 20 shown in FIG. 6 includes a dynamic characteristic prediction calculation unit 41 in addition to the configuration of the steam temperature control device 20 shown in FIG.

  The dynamic characteristic prediction calculation unit 41 has a dynamic characteristic model indicating a change in the amount of heat of the heat exchanger 6 due to a change in plant load (load command value or the like). The target value is changed. That is, the dynamic characteristic prediction calculation unit 41 uses the dynamic characteristic model to calculate a predicted value that predicts a change in the amount of heat applied to the heat exchanger 6 when the load on the plant changes, and sets the calculated result as an inlet temperature target value setting. The value is added to the target value of the inlet temperature of the heat exchanger 6 set by the unit 25.

  According to the third embodiment, in addition to the effects obtained in the first and second embodiments, the influence of the change in the amount of heat at the time of load change applied from the inlet to the outlet of the heat exchanger 6 is also achieved. It becomes possible to compensate, and it becomes possible to realize a control system that is more resistant to disturbances.

(Fourth embodiment)
A fourth embodiment will be described with reference to FIG.

  FIG. 7 is a block diagram illustrating an example of the configuration of the steam temperature control device 20 according to the fourth embodiment and the periphery of the control target. In addition, the same code | symbol is attached | subjected to the element which is common in FIG. 6, and the overlapping description is abbreviate | omitted.

  The steam temperature control device 20 shown in FIG. 7 includes a gain compensation circuit 51 in addition to the configuration of the steam temperature control device 20 shown in FIG.

  The gain compensation circuit 51 changes the gain of the output signal of the dead time / delay time compensation circuit 21A in accordance with the change in the steam energy ratio between the outlet steam and the inlet steam of the heat exchanger 6 accompanying the change in the operation state of the plant. Is. That is, the gain compensation circuit 51 uses the characteristic that the steam energy ratio such as the specific heat ratio between the inlet and the outlet of the heat exchanger 6 differs between when the plant is in a high load state and when it is in a low load state. A gain corresponding to the steam energy ratio is determined based on the command value.

  According to the fourth embodiment, in addition to the effects obtained in the first to third embodiments, when the load is high and a large amount of steam is generated, or when the load is low and the amount of steam is small, etc. Even when the operation state of the plant greatly changes, it is possible to maintain highly accurate control with dead time compensation, delay time compensation, disturbance compensation, and heat quantity change compensation.

(Fifth embodiment)
The fifth embodiment will be described with reference to FIG.

  FIG. 8 is a block diagram showing an example of the configuration of the steam temperature control device 20 according to the fifth embodiment and the periphery of the control target. In addition, the same code | symbol is attached | subjected to the element which is common in FIG. 7, and the overlapping description is abbreviate | omitted.

  The steam temperature control device 20 shown in FIG. 8 is configured to further include variable setting units 61 to 63 in the configuration of the steam temperature control device 20 shown in FIG.

  The variable setting units 61 to 63 are configured to variably set control parameters used for calculations of the dead time / delay time compensation circuit 21A, the outlet temperature control unit 24, and the inlet temperature control unit 27, respectively.

  For example, in a certain plant operating state, system identification is performed, dead time and delay time in the heat exchanger 6 are estimated, and accordingly, gains used for calculation in the dead time / delay time compensation circuit 21A, Control parameters such as dead time and time constant, control parameters such as gain used for calculation at the outlet temperature control unit 24, and control parameters such as gain used for calculation at the inlet temperature control unit 27 Calculate the optimal value. And each control parameter is set to the optimal value by the variable setting parts 61-63. Note that all or part of the series of processes can be performed using an information processing apparatus.

  According to the fifth embodiment, in addition to the effects obtained in the first to fourth embodiments, the control parameter related to the upper control and the control parameter related to the lower control according to the plant operating state, and Each of the dead time / delay time compensation can be set to an optimum value, and the control adjustment in the field can be performed efficiently.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 ... Boiler equipment, 2 ... Boiler, 3 ... Steam drum, 4 ... Evaporator, 5 ... Heat exchanger (1st heat exchanger), 6 ... Heat exchanger (2nd heat exchanger), 7 ... Reduction Heater, 8 ... control valve, 9 ... deaerator, 10 ... feed pump, 11 ... economizer, 20 ... steam temperature control device, 21 ... dead time compensation circuit, 21A ... dead time / lag time compensation circuit, 22 ... corrector, 23 ... outlet temperature target value setting part, 24 ... outlet temperature control part (first control part), 25 ... inlet temperature target value setting part, 26 ... correction part, 27 ... inlet temperature control part (second 28 ... temperature detector, 29 ... temperature detector, 30 ... control unit, 31, 31 '... dead time element, 32, 32' ... primary delay element, 33, 33 '... secondary delay element , 34... Arithmetic unit, 41... Dynamic characteristic prediction arithmetic unit, 51... Gain compensation circuit, 61 to 63.

Claims (6)

A heat exchanger that superheats the supplied steam, a temperature reducer that reduces the temperature of the steam supplied to the heat exchanger with a refrigerant, and a control valve that adjusts the amount of refrigerant supplied to the temperature reducer. In a steam temperature control device applied to a plant having a boiler facility equipped with,
Based on a signal indicating an actual measurement value of the inlet temperature of the heat exchanger, at least a dead time compensation unit that outputs a signal for compensating for a dead time generated in the heat exchanger;
Based on a value obtained by correcting an actual measured value of the outlet temperature of the heat exchanger according to a signal output from the dead time compensation circuit, and a target value of the outlet temperature of the heat exchanger, the heat exchanger First control means for outputting a first control signal for causing the outlet temperature of the gas to become equal to a target value;
Based on the measured value of the inlet temperature of the heat exchanger and the target value after correcting the target value of the inlet temperature of the heat exchanger according to the first control signal, the inlet temperature of the heat exchanger And a second control means for supplying a second control signal to the control valve so as to be equal to the corrected target value.   2. The steam temperature control device according to claim 1, wherein the dead time compensation means outputs a signal for compensating not only a dead time generated in the heat exchanger but also a delay time element. 3. Control device.   3. The steam temperature control device according to claim 1, further comprising a dynamic characteristic model indicating a change in a heat amount of the heat exchanger according to a change in a plant load, and an inlet temperature of the heat exchanger according to the dynamic characteristic model. The steam temperature control device further comprising means for changing the target value of the steam.   4. The steam temperature control device according to claim 1, wherein the dead time is determined according to a change in a steam energy ratio between an outlet steam and an inlet steam of the heat exchanger accompanying a change in an operation state of the plant. A steam temperature control device further comprising means for changing the gain of the output signal of the compensation means.   5. The steam temperature control apparatus according to claim 1, wherein at least a parameter used for each calculation of the dead time compensation unit, the first control unit, and the second control unit is provided. A steam temperature control device further comprising means for performing any variable setting. A heat exchanger that superheats the supplied steam, a temperature reducer that reduces the temperature of the steam supplied to the heat exchanger with a refrigerant, and a control valve that adjusts the amount of refrigerant supplied to the temperature reducer. In a steam temperature control method applied to a plant having a equipped boiler facility,
Based on the signal indicating the actual measured value of the inlet temperature of the heat exchanger, the dead time compensation means outputs a signal for compensating at least the dead time generated in the heat exchanger,
By the first control means, the actual value of the outlet temperature of the heat exchanger is corrected according to the signal output from the dead time compensation circuit, and the target value of the outlet temperature of the heat exchanger A first control signal that causes the outlet temperature of the heat exchanger to be equal to a target value,
Based on the measured value of the inlet temperature of the heat exchanger and the target value after correcting the target value of the inlet temperature of the heat exchanger according to the first control signal by the second control means, A steam temperature control method, comprising: supplying a second control signal to the control valve so that an inlet temperature of the heat exchanger becomes equal to the corrected target value.

Images