CN108278134B - A coordinated control method for a bus-controlled once-through boiler generator set - Google Patents

Abstract

The invention discloses a coordinated control method for a main pipe direct-current boiler generator set. The method comprises a multi-steam-turbine coordination control method and a once-through boiler coordination control method. The multi-turbine coordinated control method is used for solving the opening instruction mu of the main steam control valve by establishing a multivariable decoupling control law matrix based on error feedback_THiAnd calculating the opening command mu of the intermediate pressure regulating valve according to the flow characteristic curve of the intermediate pressure regulating valve and the flow distribution target value of the low pressure cylinder in the steam turbine_TLiThe flow of the low-pressure cylinder and the high-pressure cylinder of the steam turbine is coordinately controlled, and the coordination control of multiple steam turbines is realized. The coordinated control method of the once-through boiler obtains the combustion rate instruction mu by establishing a single-loop control law based on error feedback_BWater supply flow rate instruction mu_WAnd desuperheating Water flow instruction mu_AWAnd the coordinated control operation of the once-through boiler based on the load of the generator set is realized. The method has simple structure, hierarchical coordination control and rapid and stable adjustment.

Description

A coordinated control method for a bus-controlled once-through boiler generator set

technical field

The invention relates to a coordinated control method for a main control direct current boiler generator set, belonging to the technical field of generator set control.

Background technique

According to the goals set by the National Energy Administration's "Coal Power Energy Saving, Emission Reduction, Upgrading and Renovation Action Plan (2014-2020)", the existing coal-fired generating units must be upgraded and upgraded, and the average coal consumption for power supply by 2020 should be less than 310 g/kWh . It is a cost-effective technical choice to realize energy saving and emission reduction of coal-fired units by transforming the old subcritical units in service into super (super) critical DC units, and greatly improving their thermal cycle efficiency by increasing steam parameters.

For a typical 2×300MW subcritical unit unit, two subcritical boilers are transformed into one supercritical boiler of equivalent capacity, and two steam turbines are transformed at the same time and the original generator set is retained to realize the parent pipe of one boiler and two turbines. The supercritical DC coal-fired power generation system has better economy than the new supercritical unit, so the technology has a good application and promotion prospect. However, compared with the subcritical unit power generation and the supercritical unit power generation of the supercritical DC system of the bus tube after the transformation, the system structure is significantly different. While improving the operation flexibility, the coupling between the boiler and the steam turbine and each steam turbine is more efficient. Therefore, the coordinated control of the parent-controlled DC coal-fired power generation system has become a difficult point in the application of this technology.

In the past, the main tube power generation systems were mostly small-capacity units. The boilers were drum boilers with natural circulation. Multiple boilers and steam turbines were connected through the main steam main tube. There was no steam reheating system, and they were mainly used in self-provided power plants and central heating. In other fields, the control requirements are relatively low, and the main problem of its operation control is the stability of the main pipe pressure.

The existing control scheme of the main control drum boiler power generation system is mainly used for the control of self-provided power plants and small-capacity units for heating. Keep the pressure of the main pipe stable. Since each steam turbine does not participate in grid dispatching, there is no need to perform automatic power generation control on the load of each steam turbine according to the needs of grid dispatching. In addition, there is no reheat steam main pipe in the system, so it does not involve the adjustment of the medium pressure regulating valve. However, when the subcritical unit is transformed into a supercritical parent control unit, because the system is more complicated, and each turbine needs to participate in the grid dispatching, higher requirements are put forward for its coordinated control system.

The control of the existing DC coal-fired power generation system is mainly for units configured in a unit system, that is, one boiler is equipped with one steam turbine. Since the unit-based unit does not contain the main steam main pipe and the reheat steam main pipe, its control scheme cannot adapt to the mutual coupling and mutual interference caused by the parallel operation of the two steam turbines, and the medium pressure regulating valve of the steam turbine is not adjusted. Can not meet the needs of precise adjustment of the load.

SUMMARY OF THE INVENTION

The invention aims at a coordinated control method for a bus-tube direct-current boiler generator set. The bus-tube direct-current boiler-generator set has a steam reheating system, the coupling between the steam turbine and the boiler is tighter, and the coordinated control method can change the load in a wide range. It can still ensure the small fluctuation of the main steam pressure and the power of each steam turbine to track its load command quickly and smoothly.

The present invention is achieved through the following technical solutions:

A method for coordinated control of a bus-controlled direct current boiler generator set is used for the coordinated control of a bus-controlled direct current boiler generator set. Evaporator and superheater, the generator set includes a steam turbine high pressure cylinder, a steam turbine medium and low pressure cylinder and a generator; the feed water pump is connected with a water supply valve; a main steam pipeline is connected between the superheater and the steam turbine high pressure cylinder There are several high-pressure cylinders of the steam turbine, medium and low pressure cylinders of the steam turbine and generators, and the generators are arranged in a one-to-one correspondence with the high-pressure cylinders of the steam turbine and the medium and low pressure cylinders of the steam engine; The cylinders and the plurality of steam turbine medium and low pressure cylinders are respectively connected in parallel; a reheater is arranged between the plurality of steam turbine high pressure cylinders and the plurality of steam turbine middle and low pressure cylinders; the connection between the steam turbine high pressure cylinder and the superheater A main steam regulating valve is arranged between the two, and the main steam regulating valve and the high-pressure cylinder of the steam turbine are arranged in a one-to-one correspondence; It is set in one-to-one correspondence with the medium and low pressure cylinders of the steam turbine; it is characterized in that the coordinated control method includes a multi-turbine coordinated control method, and the multi-turbine coordinated control method includes:

Obtain the flow characteristic curve Q _TLi =fcn1(μ _TLi ) of each medium pressure regulating door, wherein Q _TLi and μ _TLi are the flow rate and door opening degree passing through each medium pressure regulating door, respectively, and i is the ith group of medium pressure regulating doors;

Based on the flow characteristic curve Q _TLi =fcn1(μ _TLi ) of the medium pressure regulating valve, carry out the calculation of the flow distribution of the corresponding medium and low pressure cylinders of the steam turbine, and obtain the flow distribution target value Q _RE,r,i of the medium and low pressure cylinders of the steam turbine; The flow distribution target value of the low-pressure cylinder is calculated by using the functional relationship Q _TLi =fcn1(μ _TLi ) to calculate the corresponding medium-pressure door opening command μ _TLi =fcn2(Q _RE,r,i ) of the medium-pressure door, the function fcn2( ) is the inverse of the function fcn1( );

Obtain the set value E _r,i and the measured value E _i of the several generator loads, and obtain the set value P _T,r and the measured value P _T of the main steam pressure, and establish a multivariable decoupling control based on error feedback law matrix, according to the multivariable decoupling control law matrix, the main steam control valve opening command μ _THi is obtained;

Multi-turbine coordinated control is achieved through coordinated control of the flow through several of the steam turbine middle and low pressure cylinders and steam turbine high pressure cylinders through each medium pressure valve opening command μ _TLi and each main steam regulating valve opening command μ _THi .

In the above technical solution, the coordinated control method further includes a once-through boiler coordinated control method, and the once-through boiler coordinated control method and the multi-turbine coordinated control method simultaneously coordinate and control the multi-turbine operation and the once-through boiler operation; the once-through boiler Coordinated control methods include:

Obtain the set value E _r of the total load of the generator set, and obtain the burning rate feedforward command μ _B0 according to the combustion rate feedforward command function μ _B0 =fcn3(E _r ) and the feedwater flow feedforward command function μ _W0 =fcn4(E _r ) respectively and feedforward command μ _W0 of water flow;

Obtain the main steam pressure setting value P _T,r , the main steam temperature setting value T _S,r and the intermediate point temperature setting value T _M,r , and obtain the main steam pressure measured value P _T , the main steam temperature measured value T _S and the measured value _TM of the midpoint temperature, establish a single-loop control law based on error feedback, and according to the functional relationship between the combustion rate feedforward command μ _B0 and feedwater flow feedforward command μ _W0 and the single-loop control law based on μ _B = μ _B0 +ctrl1(P _T,r -P _T ) and μ _W =μ _W0 +ctrl3(T _M,r -T _M ), respectively obtain the firing rate command μ _B and the feedwater flow command μ _W , which are used for the once-through boiler. The combustion condition and the water supply valve of the feed pump are coordinated and controlled; at the same time, through the difference between the main steam temperature set value T _S,r and the measured value T _S , the functional relationship based on the single-loop control law μ _AW =ctrl2(T _S,r - T _S ) obtains the desuperheating water flow command μ _AW to adjust the desuperheating water flow of the once-through boiler, wherein ctrl1(·), ctrl2(·) and ctrl3(·) are single-loop control laws based on error feedback.

In the above technical solution, when two high-pressure cylinders of the steam turbine, medium and low pressure cylinders of the steam turbine and generators are provided, the multi-variable decoupling control law matrix in the coordinated control method of the generator set is selected.

Among them, ctrl11, ctrl12, ctrl21, ctrl22 are the unit control laws in the multivariable decoupling control law matrix, respectively, μ _TH1 and μ _TH2 are the two main steam control valve opening commands, E _r,1 and E _r,2 respectively E1 and E2 are the measured load values _of the _two generators, respectively.

In the above technical solution, the function fcn1(·) can be obtained through design data or measured through field experiments.

In the above technical solution, the functions fcn3(·) and fcn4(·) can be obtained through design data or measured through field experiments.

The invention has the following advantages and beneficial effects: based on the idea of layered coordination control, the flexible adjustment of the power generation of each steam turbine connected in parallel by the main control is fully realized, and the load command of each steam turbine generator set can be tracked quickly and stably, and the main steam turbine can be ensured. The fluctuations of pressure and boiler parameters are within the allowable range; the coordinated control method is simple in structure and easy to implement in engineering, and is of great significance to the safe and stable operation of the parent tube direct current coal-fired power generation system.

Description of drawings

FIG. 1 is a schematic diagram of a control point of a bus-tube once-through boiler generator set according to one of the embodiments of the present invention.

FIG. 2 is a schematic diagram of the coupling relationship of the controlled objects of the coordinated control system of the bus-controlled once-through boiler generator set according to one of the embodiments of the present invention.

FIG. 3 is a schematic diagram of a logical structure of a coordinated control system for a bus-controlled once-through boiler generator set according to one of the embodiments of the present invention.

In the figure: 1-water supply valve; 2-evaporator; 3-superheater; 4-main steam valve; 5-turbine high-pressure cylinder; 6-reheater; 7-medium pressure regulating valve; 8-turbine low-pressure cylinder; 9 -dynamo.

Detailed ways

The specific embodiments and working process of the present invention will be further described below with reference to the accompanying drawings.

Orientation terms such as upper, lower, left, right, front and rear in this application document are established based on the positional relationship shown in the accompanying drawings. If the drawings are different, the corresponding positional relationship may also change accordingly, so this should not be construed as a limitation on the protection scope.

The present invention relates to a method for coordinated control of a bus-tube direct-current boiler-generator set, which is used for the coordinated control of a bus-tube direct-current boiler-generator set as shown in FIG. 1 . The bus-tube once-through boiler generator set includes a once-through boiler and a generator set, usually a once-through boiler is connected to two or more sets of generator sets. The once-through boiler is equipped with a feed pump, an evaporator 2 and a superheater 3. The incoming water is lifted by the feed pump and enters the heating surface of the once-through boiler, and then passes through the evaporator 2 and the superheater 3 to become high-temperature and high-pressure steam, which is distributed through the main steam pipe and enters into multiple power plants. The unit is connected to the high-pressure cylinder 5 of the steam turbine. The generator set includes a steam turbine high pressure cylinder 5, a steam turbine medium and low pressure cylinder 8 and a generator 9, wherein the steam turbine high pressure cylinder 5 and the steam turbine medium and low pressure cylinder 8 are steam turbines. A reheater 6 is arranged between the high pressure cylinder of the steam turbine and the middle and low pressure cylinders of the steam turbine. The water supply pump is connected with a water supply regulating door 1, which is the abbreviation of regulating valve and is used to regulate the water supply flow. There are several turbine high pressure cylinders 5 , turbine medium and low pressure cylinders 8 and generators 9 , and the generators 9 are provided in a one-to-one correspondence with the turbine high pressure cylinder 5 and the turbine medium and low pressure cylinders 8 . That is, the steam turbine and the generator are set in one-to-one correspondence. The plurality of steam turbine high-pressure cylinders and the plurality of steam turbine medium and low pressure cylinders are respectively connected in parallel, and the parallel steam turbine high-pressure cylinders are connected to the main pipe of the reheater. A main steam regulating valve 4 is arranged between the steam turbine high pressure cylinder 5 and the superheater 3 , and the main steam regulating valve 4 is arranged in a one-to-one correspondence with the steam turbine high pressure cylinder 5 . A medium pressure regulating valve 7 is arranged between the medium and low pressure cylinders 8 of the steam turbine and the reheater 6 , and the medium pressure regulating valves 7 are arranged in a one-to-one correspondence with the medium and low pressure cylinders 8 of the steam turbine.

A coordinated control method for a bus-controlled once-through boiler generator set includes a multi-turbine coordinated control method and/or a once-through boiler coordinated control method, respectively or simultaneously controlling the multi-turbine operation and the once-through boiler operation.

The multi-turbine coordinated control method includes:

Obtain the flow characteristic curve Q _TLi =fcn1(μ _TLi ) of each medium pressure regulating door 7 , wherein Q _TLi and μ _TLi are the flow rate and door opening degree passing through each medium pressure regulating door 7 respectively, and i is the i-th medium pressure regulating door 7 ;

Based on the flow characteristic curve Q _TLi =fcn1(μ _TLi ) of the medium pressure regulating valve 7, carry out the calculation of the flow distribution of the corresponding medium and low pressure cylinders 8 of the steam turbine, and obtain the flow distribution target value Q _RE,r,i of the medium and low pressure cylinders 8 of the steam turbine; and According to the flow distribution target value of the medium and low pressure cylinders 8 of the steam turbine, use Q _TLi =fcn1(μ _TLi ) to calculate the corresponding medium pressure valve opening command μ _TLi =fcn2(Q _RE,r,i ) of the medium pressure valve 7, the said The function fcn2(·) is the inverse of the function fcn1(·);

Obtain the set value E _r,i and the measured value E _i of the several generator loads, and obtain the set value P _T,r and the measured value P _T of the main steam pressure, and establish a multivariable decoupling control based on error feedback law matrix, according to the multivariable decoupling control law matrix, the main steam control valve opening command μ _THi is obtained;

The multi-turbine coordinated control is realized by coordinated control of the flow through a plurality of the steam turbine medium and low pressure cylinders and the steam turbine high pressure cylinder through the medium pressure valve opening command μ _TLi and the main steam regulating valve opening command μ _THi .

The coordinated control methods of once-through boilers include:

Obtain the set value E _r of the total load of the generator set, and obtain the burning rate feedforward command μ _B0 according to the combustion rate feedforward command function μ _B0 =fcn3(E _r ) and the feedwater flow feedforward command function μ _W0 =fcn4(E _r ) respectively and feedforward command μ _W0 of water flow;

Obtain the main steam pressure setting value P _T,r , the main steam temperature setting value T _S,r and the intermediate point temperature setting value T _M,r , and obtain the main steam pressure measured value P _T , the main steam temperature measured value T _S and the measured value _TM of the midpoint temperature, establish a single-loop control law based on error feedback, and according to the functional relationship between the combustion rate feedforward command μ _B0 and feedwater flow feedforward command μ _W0 and the single-loop control law based on μ _B = μ _B0 +ctrl1(P _T,r -P _T ) and μ _W =μ _W0 +ctrl3(T _M,r -T _M ), respectively obtain the firing rate command μ _B and the feedwater flow command μ _W , which are used for the once-through boiler. The combustion conditions and the water supply valve 1 of the feed pump are coordinated and controlled; at the same time, through the difference between the main steam temperature set value T _S,r and the measured value T _S , the functional relationship based on the single-loop control law μ _AW =ctrl2(T _S,r -T _S ) to obtain the desuperheating water flow command μ _AW to adjust the desuperheating water flow of the once-through boiler, wherein ctrl1(·), ctrl2(·) and ctrl3(·) are single-loop control laws based on error feedback.

When there are two turbine high-pressure cylinders 5, turbine medium-low pressure cylinders 8 and generators 9, the multi-variable decoupling control law matrix in the generator set coordinated control method is selected

Among them, ctrl11, ctrl12, ctrl21, and ctrl22 are the unit control laws in the multivariable decoupling control law matrix, respectively.

The function fcn1(·) can be obtained through design data or measured through field experiments.

The functions fcn3(·) and fcn4(·) can be obtained through design data or measured through field experiments.

The coordinated control method of the once-through boiler of the present invention is not purely based on the control of the boiler itself, but is based on the coordinated adjustment and control of the boiler combustion state, the amount of feed water and the amount of desuperheating water based on the load change of the generator set.

One of the embodiments is that one 600MW supercritical boiler is equipped with two 300MW supercritical parameter steam turbines.

According to the design data, through curve fitting, the flow characteristic curves of the medium-pressure regulating valve 7 of the two steam turbines are obtained as:

Wherein μ _TL1 and μ _TL2 are respectively the opening degrees of the two steam turbine medium pressure regulating valves, and Q _TL1 and Q _TL1 are respectively the flow through the two steam turbine medium pressure regulating doors.

Assuming that the set values of the two generator loads are E _r,1 and E _r,1 respectively, then based on the flow characteristic curve of the medium pressure regulating valve, the flow distribution calculation of the medium and low pressure cylinders of the two turbines is carried out, and the flow distribution of the two turbines is obtained. The flow distribution target value of the low pressure cylinder is as follows:

According to the above-mentioned target value of flow distribution of the medium and low pressure cylinders of the steam turbine, calculate the medium pressure valve opening command μ _TL1 =fcn2(Q _RE,r,1 ), μ _TL2 =fcn2(Q _RE,r,2 ).

According to the set values E _r,1 and E _r,1 of the two steam turbine generator loads, the measured values E ₁ and E ₂ of the two steam turbine generator loads, and the set value of the main steam pressure P _T,r and the measured value P _T , establish a multi-variable PID decoupling control law matrix based on error feedback, and obtain the opening commands μ _TH1 and μ _TH2 of the main steam control valves of the two steam turbines according to the multi-variable decoupling control law matrix as follows:

Wherein, the coefficients K _p11 , K _i11 , K _d11 are the control parameters of the PID controller ctrl11, the coefficients K _p12 , K _i12 , K _d12 are the control parameters of the PID controller ctrl12, and the coefficients K _p21 , K _i21 , K _d21 are the PID control parameters The control parameters of the controller ctrl21, the coefficients K _p22 , K _i22 , and K _d22 are the control parameters of the PID controller ctrl22. The above control parameters are obtained through on-site debugging according to the actual characteristics of the unit.

Thereby, the opening command of the main steam regulating valve and the command of the opening degree of the medium voltage regulating valve of the coordinated control of the two turbo-generator sets are obtained.

According to the set value E _r of the total load of the generator set, the combustion rate feedforward command μ _B0 and the feedwater flow feedforward command μ _W0 are obtained as follows:

μ _B0 =min(1.0,max(0.3,0.0018E _r )),

_μW0 =min(1833, max(831, 3.32E _r )).

According to the main steam pressure set value P _T,r and the main steam pressure measured value P _T , a single-loop control law based on error feedback is established (taking the traditional PID control law as an example), and the combustion rate command μ _B is obtained as follows:

According to the set value T _M,r of the intermediate point temperature and the measured value T _M of the intermediate point temperature, a single-loop control law based on error feedback is established (taking the traditional PID control law as an example), and the water flow command μ _W is obtained as follows:

According to the main steam temperature set value T _S,r and the measured value T _S , a single-loop control law based on error feedback is established (taking the traditional PID control law as an example), and the desuperheating water flow command μ _AW is obtained as follows:

Among them, the coefficients K _p1 , K _i1 , K _d1 are the control parameters of the PID controller ctrl1, the coefficients K _p2 , K _i2 , K _d2 are the control parameters of the PID controller ctrl2, and the coefficients K _p3 , K _i3 , K _d3 are the PID control parameters Control parameters of the controller ctrl3.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (5)

1. a coordinated control method for a parent-controlled direct-current boiler generator set, the parent-controlled direct-current boiler generator set comprises a direct-current boiler and a generator set, and the once-through boiler is provided with a feed water pump, an evaporator (2) and a superheater (3), The generator set comprises a steam turbine high pressure cylinder (5), a steam turbine medium and low pressure cylinder (8) and a generator (9); the feed water pump is connected with a feed water regulating valve (1); the superheater (3) is connected to the steam turbine high pressure A main steam pipeline connection is provided between the cylinders (5); a number of the steam turbine high pressure cylinder (5), the steam turbine medium and low pressure cylinder (8) and the generator (9) are all provided, and the generator (9) is connected to The steam turbine high-pressure cylinders (5) and the steam turbine medium and low pressure cylinders (8) are arranged in a one-to-one correspondence; the plurality of steam turbine high-pressure cylinders and the plurality of steam turbine middle and low pressure cylinders are respectively connected in parallel; A reheater (6) is arranged between the high pressure cylinder and the plurality of steam turbine medium and low pressure cylinders; a main steam regulating valve (4) is arranged between the steam turbine high pressure cylinder (5) and the superheater (3), and The main steam regulating valve (4) is arranged in a one-to-one correspondence with the high pressure cylinder (5) of the steam turbine; a medium pressure regulating valve (7) is arranged between the middle and low pressure cylinder (5) of the steam turbine and the reheater (6). , and the medium pressure regulating valve (7) and the medium and low pressure cylinders (8) of the steam turbine are arranged in one-to-one correspondence; it is characterized in that the coordinated control method includes a multi-turbine coordinated control method, and the multi-turbine coordinated control method includes: Obtain the flow characteristic curve Q _TLi =fcn1(μ _TLi ) of each medium pressure regulating door (7), wherein Q _TLi and μ _TLi are the flow rate and door opening degree passing through the medium pressure regulating door (7), respectively, and i is the first i medium-voltage regulating doors (7); Based on the flow characteristic curve Q _TLi =fcn1(μ _TLi ) of the medium pressure regulating valve (7), calculate the flow distribution of the corresponding medium and low pressure cylinders (8) of the steam turbine, and obtain the target value Q of flow distribution of the medium and low pressure cylinders (8) of the steam turbine. _RE,r,i ; and according to the flow distribution target value Q _RE,r,i of the low-pressure cylinder (8) in the steam turbine, use the functional relationship Q _TLi =fcn1(μ _TLi ) to calculate the medium pressure of the corresponding medium pressure regulating valve (7) door opening instruction μ _TLi =fcn2(Q _RE,r,i ), the function fcn2(·) is the inverse function of the function fcn1(·); Obtain the set value E _r,i and the measured value E _i of the several generator loads, and obtain the set value P _T,r and the measured value P _T of the main steam pressure, and establish a multivariable decoupling control based on error feedback law matrix, according to the multivariable decoupling control law matrix to obtain the opening command μ _THi of each main steam control valve; The multi-turbine coordinated control is realized through coordinated control of the flow of each medium pressure valve opening degree command μ _TLi and each main steam control valve opening degree command μ _THi through a plurality of the steam turbine medium and low pressure cylinders (8) and the steam turbine high pressure cylinder (5). 2 . The method for coordinated control of a once-through boiler generator set according to claim 1 , wherein the coordinated control method further comprises a coordinated control method for a once-through boiler, the coordinated control method for a once-through boiler and the multi-turbine boiler. 3 . With the coordinated control method, the multi-turbine operation and the once-through boiler operation are simultaneously coordinated and controlled; the once-through boiler coordinated control method includes: Obtain the set value E _r of the total load of the generator set, and obtain the burning rate feedforward command μ _B0 according to the combustion rate feedforward command function μ _B0 =fcn3(E _r ) and the feedwater flow feedforward command function μ _W0 =fcn4(E _r ) respectively and feedforward command μ _W0 of water flow; Obtain the main steam pressure setting value P _T,r , the main steam temperature setting value T _S,r and the intermediate point temperature setting value T _M,r , and obtain the main steam pressure measured value P _T , the main steam temperature measured value T _S and the measured value _TM of the midpoint temperature, establish a single-loop control law based on error feedback, and according to the functional relationship between the combustion rate feedforward command μ _B0 and feedwater flow feedforward command μ _W0 and the single-loop control law based on μ _B = μ _B0 +ctrl1(P _T,r -P _T ) and μ _W =μ _W0 +ctrl3(T _M,r -T _M ), respectively obtain the firing rate command μ _B and the feedwater flow command μ _W , which are used for the once-through boiler. The combustion conditions and the water supply valve (1) of the feed pump are coordinated and controlled; at the same time, through the difference between the main steam temperature set value T _S,r and the measured value T _S , the functional relationship based on the single-loop control law μ _AW =ctrl2(T _{S ,r} -T _S ) to obtain the desuperheating water flow command μ _AW to adjust the desuperheating water flow of the once-through boiler, wherein ctrl1(·), ctrl2(·) and ctrl3(·) are single-loop control laws based on error feedback. 3. The method for coordinating control of a main control direct current boiler generator set according to claim 1, characterized in that: when the steam turbine high pressure cylinder (5), the steam turbine medium and low pressure cylinder (8) and the generator (9) are all set When there are two, the multi-variable decoupling control law matrix is selected in the coordinated control method of the generator set.

Among them, ctrl11, ctrl12, ctrl21, ctrl22 are the unit control laws in the multivariable decoupling control law matrix, respectively, μ _TH1 and μ _TH2 are the two main steam control valve opening commands, E _r,1 and E _r,2 respectively E1 and E2 are the measured load values _of the _two generators, respectively. 4 . The method for coordinated control of a bus-controlled once-through boiler generator set according to claim 1 , wherein the function fcn1(·) can be obtained through design data or measured through field experiments. 5 . 5 . The method for coordinated control of a bus-controlled once-through boiler generator set according to claim 2 , wherein the functions fcn3(·) and fcn4(·) can be obtained through design data or measured through field experiments. 6 .

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