Feedforward control system and method for thermal power unit

Abstract

The present invention belongs to the field of thermal power control and provides a feedforward control system and method for a thermal power unit. The system includes: a data acquisition unit for acquiring the operating parameters and load setting parameters of the thermal power unit; a correction calculation unit for determining the key calorific value of the thermal power unit and the boiler design efficiency based on the operating parameters, and calculating the boiler efficiency correction factor; a state detection unit for generating a load control instruction based on the load setting parameters, judging the operating state of the thermal power unit, and obtaining a state judgment result; a parameter generation unit for determining correction values for various parameters of the thermal power unit; and a feedforward control unit for generating and correcting a feedforward control variable based on the load control instruction, the state judgment result, and the various parameter correction values, and performing feedforward control of the thermal power unit based on the corrected feedforward control variable. The solution provided by the present invention utilizes a multi-parameter comprehensive correction mechanism to improve the control efficiency and control stability of the feedforward control link.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal power control, and in particular to a feedforward control system and method for a thermal power unit. Background Art

[0002] As a vital component of my country's power system, the stable and efficient operation of thermal power units is crucial for ensuring power supply. However, the operational control of thermal power units presents numerous challenges. Firstly, the operating conditions of thermal power units are complex and variable, and frequent fluctuations in load demand can significantly impact their operational stability. For example, when loads fluctuate rapidly, key parameters such as boiler combustion and turbine speed are difficult to adjust promptly and accurately, leading to fluctuations in the controlled variables and impacting the safety and economic efficiency of the thermal power units. Secondly, due to the influence of coal prices, coal blending is common in thermal power units, resulting in frequent changes in coal quality. Existing control architectures and parameters are difficult to adapt to, resulting in frequent fluctuations in key operating parameters and making it difficult to meet the requirements for safe and stable operation of thermal power units.

[0003] The introduction of feedforward control can, to a certain extent, overcome these control difficulties. However, traditional feedforward control schemes still have certain limitations when dealing with these complex operating conditions. For example, while differential feedforward control schemes can quickly respond to load changes, they can easily cause excessive fluctuations in the controlled variable, leading to large overshoots and thus affecting the stable operation of thermal power units. Furthermore, due to imperfect control processes, operating parameters of thermal power units struggle to quickly return to target values after variable load conditions. Furthermore, traditional feedforward control schemes suffer from low control efficiency and poor control stability.

[0004] It is not difficult to find that the traditional feedforward control scheme has technical problems such as low control accuracy, low control efficiency and poor control stability. Summary of the Invention

[0005] The present invention provides a feedforward control system and method for a thermal power unit, which are used to solve the defects of a traditional feedforward control scheme, such as low control precision, low control efficiency and poor control stability.

[0006] In one aspect, the present invention provides a feedforward control system for a thermal power plant, comprising:

[0007] Data acquisition unit, used to obtain the operating parameters and load setting parameters of the thermal power unit;

[0008] a correction calculation unit, configured to determine a key calorific value and a boiler design efficiency of the thermal power unit according to the operating parameters, and calculate a boiler efficiency correction coefficient according to the key calorific value and the boiler design efficiency;

[0009] A state detection unit is used to generate a load control instruction according to the load setting parameter, and to judge the operating state of the thermal power unit to obtain a state judgment result;

[0010] a parameter generating unit, configured to determine correction values of various parameters of the thermal power unit according to the boiler efficiency correction coefficient and the state judgment result;

[0011] A feedforward control unit is used to generate and correct a feedforward control quantity according to the load control instruction, the state judgment result and the multiple parameter correction values, and perform feedforward control on the thermal power unit according to the corrected feedforward control quantity.

[0012] According to the feedforward control system of the thermal power unit provided by the present invention, the operating parameters include: main steam temperature, main steam pressure, main steam flow, feed water temperature, feed water pressure, feed water flow, active power and actual coal quantity;

[0013] The key calorific values include: main steam heat, feed water heat and coal calorific value.

[0014] According to the feedforward control system of the thermal power unit provided by the present invention, the correction calculation unit includes:

[0015] a first calculation module, configured to determine a main steam enthalpy value according to the main steam temperature and the main steam pressure, and multiply the main steam flow rate by the main steam enthalpy value to obtain a main steam heat;

[0016] a second calculation module, configured to determine a feedwater enthalpy value based on the feedwater temperature and the feedwater pressure, and multiply the feedwater flow rate by the feedwater enthalpy value to obtain a feedwater heat value;

[0017] a third calculation module, configured to generate a design coal quantity based on the active power and a preset boiler design coal quantity curve, calculate the quotient of the design coal quantity and the actual coal quantity to obtain a coal quantity ratio, and multiply the coal ratio by the design coal calorific value to obtain the coal calorific value;

[0018] a third calculation module, configured to generate a boiler design efficiency based on the active power and a preset boiler design efficiency curve;

[0019] The fourth calculation module is used to calculate the boiler efficiency correction coefficient based on the main steam heat, feed water heat, coal calorific value and boiler design efficiency.

[0020] According to the feedforward control system of the thermal power unit provided by the present invention, the fourth calculation module calculates the boiler efficiency correction coefficient based on the main steam heat, feed water heat, coal calorific value and boiler design efficiency, including:

[0021] Subtract the main steam heat from the feed water heat to calculate the working medium absorption heat;

[0022] The actual efficiency of the boiler is calculated by dividing the heat absorbed by the working medium by the calorific value of the coal;

[0023] The boiler efficiency correction coefficient is calculated by dividing the boiler design efficiency by the boiler actual efficiency.

[0024] According to the feedforward control system of the thermal power unit provided by the present invention, the parameter generating unit includes:

[0025] A first generating module is configured to use the boiler efficiency correction coefficient at the current moment as the efficiency correction holding value when the state judgment result is a variable load state;

[0026] The second generating module is used to generate parameter correction values corresponding to each parameter setting value according to the efficiency correction maintaining value and a plurality of preset parameter setting values.

[0027] According to the feedforward control system of the thermal power unit provided by the present invention, the multiple parameter setting values include: a starting rate standard value, a starting amplitude standard value, a starting callback time standard value, a load change rate setting value, and a callback time setting value;

[0028] The second generation module includes:

[0029] The first submodule is configured to multiply the efficiency correction hold value by the startup rate standard value, the startup amplitude standard value, and the startup callback time standard value, respectively, to obtain a startup rate correction value, a startup amplitude correction value, and a startup amount callback time correction value;

[0030] A second submodule is configured to determine a load increase reference rate correction coefficient based on the efficiency correction hold value and a preset load increase reference rate correction curve, and multiply the load reference rate correction coefficient by a load change rate setting value to obtain a load increase reference rate correction value;

[0031] A third submodule is configured to determine a load reduction reference rate correction coefficient based on the efficiency correction hold value and a preset load reduction reference rate correction curve, and multiply the load reduction reference rate correction coefficient by a load change rate setting value to obtain a load reduction reference rate correction value;

[0032] a fourth submodule, configured to determine a load-increase callback time correction coefficient based on the efficiency correction hold value and a preset load-increase callback time correction curve, and multiply the load-increase callback time correction coefficient by a callback time setting value to obtain a load-increase callback time correction value;

[0033] The fifth submodule is used to determine the load reduction callback time correction coefficient based on the efficiency correction holding value and the preset load reduction callback time correction curve, and multiply the load reduction callback time correction coefficient by the callback time setting value to obtain the load reduction callback time correction value.

[0034] According to the feedforward control system of the thermal power unit provided by the present invention, the feedforward control unit includes:

[0035] a starting module, configured to generate a feedforward starting amount according to the starting rate correction value, the starting amplitude correction value, and the starting amount callback time correction value upon receiving the load control instruction;

[0036] a reference quantity generating module, configured to generate a feedforward reference quantity according to the load increase reference rate correction value and the load decrease reference rate correction value upon receiving the load control instruction;

[0037] a callback module, configured to sum the feedforward starting amount and the feedforward reference amount to obtain a feedforward superposition amount, and, after determining that a callback phase has begun according to the state judgment result, to move the feedforward superposition amount closer to the feedforward set amount corresponding to the load control instruction according to the load increase callback time correction value or the load decrease callback time correction value;

[0038] A switching module, configured to switch the feedforward callback amount in the callback phase with the feedforward set amount corresponding to the load control instruction to obtain a feedforward control amount;

[0039] an auxiliary control quantity correction module, configured to correct the feedforward control quantity according to a preset auxiliary control quantity correction coefficient to obtain a corrected feedforward control quantity;

[0040] The control module is used to perform feedforward control on the thermal power unit according to the corrected feedforward control quantity.

[0041] According to the feedforward control system of the thermal power unit provided by the present invention, the callback module determines to enter the callback stage according to the state judgment result, including:

[0042] When the state judgment result is a variable load state, determining a first duration for the thermal power unit to be in the variable load state and a second duration for the feedforward reference amount to act;

[0043] If the first duration is greater than or equal to the second duration, it is determined that the callback phase has begun.

[0044] According to the feedforward control system of the thermal power unit provided by the present invention, when the auxiliary control variable is mainly steam pressure, the auxiliary control variable correction coefficient is dynamically valued according to the load state;

[0045] When the load state is in a steady state, the auxiliary control amount correction coefficient is 1;

[0046] When the load state is in a variable load state, the auxiliary control amount correction coefficient is set to a value of 0.8 to 1.2;

[0047] When the variable load state ends, the auxiliary control value correction coefficient is adjusted from the current value to 1 according to the preset adjustment time.

[0048] On the other hand, the present invention further provides a feedforward control method for a thermal power plant, which is based on any of the above-mentioned feedforward control systems for a thermal power plant, and comprises:

[0049] Obtaining the operating parameters and load setting parameters of the thermal power unit through the data acquisition unit;

[0050] Determining the critical calorific value and boiler design efficiency of the thermal power unit based on the operating parameters through a correction calculation unit, and calculating a boiler efficiency correction coefficient based on the critical calorific value and the boiler design efficiency;

[0051] Generate a load control instruction according to the load setting parameter through the state detection unit, and judge the operating state of the thermal power unit to obtain a state judgment result;

[0052] Determining, by a parameter generating unit, various parameter correction values of the thermal power unit according to the boiler efficiency correction coefficient and the state judgment result;

[0053] The feedforward control unit generates and corrects the feedforward control quantity according to the load control instruction, the state judgment result and the multiple parameter correction values, and performs feedforward control on the thermal power unit according to the corrected feedforward control quantity.

[0054] The present invention provides a feedforward control system and method for a thermal power unit. A data acquisition unit acquires operating parameters and load setting parameters of the thermal power unit. A correction calculation unit determines the critical calorific value and boiler design efficiency of the thermal power unit based on the operating parameters, and calculates a boiler efficiency correction coefficient based on the critical calorific value and boiler design efficiency. A state detection unit generates a load control instruction based on the load setting parameters, judges the operating state of the thermal power unit, and obtains a state judgment result. A parameter generation unit determines correction values for various parameters of the thermal power unit based on the boiler efficiency correction coefficient and the state judgment result. Finally, a feedforward control unit generates and corrects a feedforward control quantity based on the load control instruction, the state judgment result, and the various parameter correction values. Feedforward control of the thermal power unit is performed based on the corrected feedforward control quantity. By utilizing a multi-parameter comprehensive correction mechanism, the accuracy of the feedforward control can be effectively improved, overshoot can be effectively suppressed, and load variation requirements under different operating conditions can be adapted, thereby improving the control efficiency and stability of the feedforward control link. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0056] Figure 1 Schematic diagram of the structure of a feedforward control system for a thermal power plant provided by an embodiment of the present invention;

[0057] Figure 2 It is a schematic diagram of the principle of data acquisition unit acquiring data;

[0058] Figure 3 This is a schematic diagram of the implementation principle of the first computing module;

[0059] Figure 4 Schematic diagram of the implementation principle of the second computing module;

[0060] Figure 5 This is a schematic diagram of the implementation principle of the third computing module;

[0061] Figure 6 Schematic diagram of the implementation principle of the fourth computing module;

[0062] Figure 7 This is a schematic diagram of the implementation principle of the state detection unit;

[0063] Figure 8 This is a schematic diagram of the implementation principle of the first generation module;

[0064] Figure 9 This is a schematic diagram of the implementation principle of the first submodule;

[0065] Figure 10 is a schematic diagram of the implementation principles of the submodules other than the first submodule in the second generation module;

[0066] Figure 11 This is a schematic diagram of the principle of determining the variable load time;

[0067] Figure 12 This is a schematic diagram of the principle of determining the action time of the feed reference quantity;

[0068] Figure 13 This is a schematic diagram of the implementation principle of the feedforward control unit;

[0069] Figure 14 It is the curve diagram generated by the feedforward control quantity;

[0070] Figure 15The figure is a flow chart of a feedforward control method for a thermal power plant provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0071] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0072] The following combination Figures 1 to 15 The detailed scheme of the feedforward control system and method of a thermal power unit provided by an embodiment of the present invention is described.

[0073] Figure 1 It is a structural diagram of a feedforward control system of a thermal power unit provided by an embodiment of the present invention.

[0074] like Figure 1 As shown, the feedforward control system of a thermal power plant provided by the embodiment of the present invention specifically includes:

[0075] The data acquisition unit 110 is used to obtain the operating parameters and load setting parameters of the thermal power unit.

[0076] The correction calculation unit 120 is used to determine the key calorific value and boiler design efficiency of the thermal power unit according to the operating parameters of the thermal power unit, and calculate the boiler efficiency correction coefficient based on the key calorific value and boiler design efficiency.

[0077] The state detection unit 130 is used to generate a load control instruction according to the load setting parameters of the thermal power unit, and to judge the operating state of the thermal power unit to obtain a state judgment result.

[0078] The parameter generating unit 140 is used to determine the correction values of various parameters of the thermal power unit according to the boiler efficiency correction coefficient and the state judgment result.

[0079] The feedforward control unit 150 is used to generate and correct the feedforward control quantity according to the load control instruction, the state judgment result and the correction values of various parameters, and perform feedforward control on the thermal power unit according to the corrected feedforward control quantity.

[0080] In one embodiment, if Figure 2 As shown, the operating parameters of the thermal power unit acquired by the data acquisition unit 110 mainly include: main steam temperature, main steam pressure, main steam flow, feed water temperature, feed water pressure, feed water flow, active power and actual coal quantity and other information related to the operation of the thermal power unit.

[0081] See also Figure 2 The load setting parameters acquired by the data acquisition unit 110 mainly include: load setting value, load change rate setting value and other user setting data related to the load.

[0082] In one embodiment, the key calorific value specifically includes: main steam heat, feed water heat, and coal heat.

[0083] The correction calculation unit specifically includes:

[0084] The first calculation module is used to determine the main steam enthalpy value according to the main steam temperature and the main steam pressure, and multiply the main steam flow rate by the main steam enthalpy value to obtain the main steam heat.

[0085] The second calculation module is used to determine the feed water enthalpy value according to the feed water temperature and the feed water pressure, and multiply the feed water flow rate by the feed water enthalpy value to obtain the feed water heat.

[0086] The third calculation module is used to generate the design coal quantity based on the active power and the preset boiler design coal quantity curve, divide the design coal quantity by the actual coal quantity to obtain the coal quantity ratio, and multiply the coal ratio by the design coal type calorific value to obtain the coal calorific value.

[0087] The third calculation module is used to generate the boiler design efficiency based on the active power and the preset boiler design efficiency curve;

[0088] The fourth calculation module is used to calculate the boiler efficiency correction factor based on the main steam heat, feed water heat, coal calorific value and boiler design efficiency.

[0089] In this embodiment, see Figure 3 The first calculation module is mainly implemented by the first enthalpy value calculation submodule 210 and the first multiplier 220. Specifically, the main steam temperature and the main steam pressure are input into the first enthalpy value calculation module 210, and the first enthalpy value calculation module 210 can output the main steam enthalpy value. Subsequently, the main steam flow rate and the main steam enthalpy value are input into the first multiplier 220, and the main steam flow rate and the main steam enthalpy value are multiplied by the first multiplier 220 to obtain the main steam heat.

[0090] See also Figure 4 The second calculation module is mainly implemented by the second enthalpy value calculation submodule 310 and the second multiplier 320. Specifically, the water supply temperature and water supply pressure are input into the second enthalpy value calculation submodule 310, and the second enthalpy value calculation submodule 310 can output the water supply enthalpy value. Subsequently, the water supply flow rate and the water supply enthalpy value are input into the second multiplier 320, and the water supply flow rate and the water supply enthalpy value are multiplied by the second multiplier 320 to obtain the water supply heat.

[0091] See also Figure 5The third calculation module is mainly implemented by the first divider 410 and the third multiplier 420. Specifically, the design coal quantity can be determined based on the active power and the preset boiler design coal quantity curve, and then the design coal quantity and the actual coal quantity are input into the first divider 410. The first divider 410 divides the design coal quantity and the actual coal quantity to obtain the coal quantity ratio. Subsequently, the coal burning ratio and the design coal type calorific value are input into the third multiplier 420. The third multiplier 420 multiplies the coal burning ratio and the design coal type calorific value to obtain the coal burning calorific value.

[0092] In one embodiment, the fourth calculation module calculates the boiler efficiency correction factor based on the main steam heat, feed water heat, coal calorific value, and boiler design efficiency, specifically including:

[0093] Subtract the main steam heat from the feed water heat to calculate the heat absorbed by the working fluid.

[0094] The actual efficiency of the boiler is calculated by dividing the heat absorbed by the working fluid by the calorific value of the coal.

[0095] The boiler efficiency correction factor is calculated by dividing the boiler design efficiency by the actual boiler efficiency.

[0096] See also Figure 6 The fourth calculation module can be implemented by a first subtractor 510, a second divider 520, and a third divider 530. The first subtractor 510 subtracts the main steam heat from the feed water heat to calculate the working fluid absorption heat. Then, the second divider 520 divides the working fluid absorption heat by the corrected coal calorific value to calculate the actual boiler efficiency. Finally, the third divider 530 divides the boiler design efficiency obtained based on the active power and the boiler design efficiency curve by the actual boiler efficiency to calculate the boiler efficiency correction coefficient.

[0097] In this embodiment, the calculation formula of the boiler efficiency correction coefficient is as follows:

[0098] (1)

[0099] Where, is the boiler efficiency correction factor, is the boiler design efficiency, The main steam heat, is the heat of water, is the corrected calorific value of coal.

[0100] In this embodiment, the state detection unit can generate a load control instruction based on the load setting parameters of the thermal power unit, specifically the load setting value and the load change rate setting value, and judge the operating state of the thermal power unit to obtain a state judgment result that can characterize the variable load state or the steady state, wherein the variable load state can be a load increase state or a load decrease state.

[0101] like Figure 7 As shown, the state detection unit in this embodiment is specifically implemented by a first rate limiter 610, a differential operator 620, a first comparator 630, a second comparator 640, a first NOT operator 650, a second NOT operator 660, a first AND operator 670 and a third NOT operator 680.

[0102] Specifically, the load setting value and the load change rate setting value are input into the first rate limiter 610 to obtain the load control instruction output by the first rate limiter 610. The load control instruction is input into the differential operator 620 to obtain the load instruction differential result output by the differential operator 620. Subsequently, the load instruction differential result and the preset load increase dead zone are input into the first comparator 630. When the value in the load instruction differential result exceeds the load increase dead zone, it is determined that the load increase state is entered; the load instruction differential result and the preset load reduction dead zone are input into the second comparator 640. When the value in the load instruction differential result is lower than the load reduction dead zone, the load increase state is entered. When in the dead zone, it is determined that the load reduction state has been entered, and the comparison result output by the first comparator 630 is input into the first NOT operator 650, and the comparison result input by the second comparator 640 is input into the second NOT operator 660, and the result output by the first NOT operator 650 and the result output by the second NOT operator 660 are both input into the first AND operator 670. In one case, the state judgment result can be determined to be a steady state based on the result output by the first AND operator 670. In another case, the result output by the first AND operator 670 can be input into the third NOT operator 680, and the state judgment result can be determined to be a variable load state.

[0103] In one embodiment, the parameter generation unit specifically includes:

[0104] The first generating module is used to use the boiler efficiency correction coefficient at the current moment as the efficiency correction holding value when the state judgment result is a variable load state.

[0105] The second generating module is used to generate parameter correction values corresponding to each parameter setting value according to the efficiency correction holding value and a plurality of preset parameter setting values.

[0106] See also Figure 8The first generation module can be specifically implemented by the first selection operator 710. Specifically, under the variable load state, the selection enable signal is input into the first selection operator 710. At the same time, the boiler efficiency correction coefficient is also used as input data of the first selection operator 710. The first selection operator 710 can output the efficiency correction maintenance value.

[0107] In a specific implementation, the second generation module specifically includes:

[0108] The first submodule is used to multiply the efficiency correction hold value with the preset starting rate standard value, starting amplitude standard value and starting callback time standard value respectively to obtain the starting rate correction value, starting amplitude correction value and starting amount callback time correction value.

[0109] The second submodule is used to determine the load increase reference rate correction coefficient based on the efficiency correction holding value and the preset load increase reference rate correction curve, and multiply the load reference rate correction coefficient by the load change rate setting value to obtain the load increase reference rate correction value.

[0110] The third submodule is used to determine the load reduction reference rate correction coefficient based on the efficiency correction holding value and the preset load reduction reference rate correction curve, and multiply the load reduction reference rate correction coefficient by the load change rate setting value to obtain the load reduction reference rate correction value.

[0111] The fourth submodule is used to determine the load increase callback time correction coefficient based on the efficiency correction holding value and the preset load increase callback time correction curve, and multiply the load increase callback time correction coefficient by the callback time setting value to obtain the load increase callback time correction value.

[0112] The fifth submodule is used to determine the load reduction callback time correction coefficient based on the efficiency correction holding value and the preset load reduction callback time correction curve, and multiply the load reduction callback time correction coefficient by the callback time setting value to obtain the load reduction callback time correction value.

[0113] See also Figure 9 The first submodule can be specifically implemented by the fourth multiplier 720, the fifth multiplier 730 and the sixth multiplier 740. Specifically, the efficiency correction holding value and the preset startup rate standard value are input into the fourth multiplier 720, and the startup rate correction value can be obtained through multiplication operation; the efficiency correction holding value and the startup amplitude standard value are input into the fifth multiplier 730, and the startup amplitude correction value can be obtained through multiplication operation; the efficiency correction holding value and the startup callback time standard value are input into the sixth multiplier 740, and the startup amount callback time correction value can be obtained through multiplication operation.

[0114] See also Figure 10The second submodule can be implemented by the seventh multiplier 750. Specifically, the load reference rate correction coefficient can be determined based on the efficiency correction holding value and the preset load reference rate correction curve. Subsequently, the load reference rate correction coefficient and the load change rate setting value are input into the seventh multiplier 750, and the load reference rate correction value can be obtained through multiplication operation.

[0115] See also Figure 10 The third submodule can be implemented by the eighth multiplier 760. Specifically, the load reduction reference rate correction coefficient can be determined based on the efficiency correction holding value and the preset load reduction reference rate correction curve. Subsequently, the load reduction reference rate correction coefficient and the load change rate setting value are input into the eighth multiplier 760, and the load reduction reference rate correction value can be obtained through multiplication operation.

[0116] See also Figure 10 The fourth submodule can be implemented by the ninth multiplier 770. Specifically, the load-increasing callback time correction coefficient can be determined based on the efficiency correction holding value and the preset load-increasing callback time correction curve. Subsequently, the load-increasing callback time correction coefficient and the callback time setting value are input into the ninth multiplier 770, and the load-increasing callback time correction value can be obtained through multiplication operation.

[0117] See also Figure 10 The fifth submodule can be implemented by the tenth multiplier 780. Specifically, based on the efficiency correction holding value and the preset load reduction callback time correction curve, the load reduction callback time correction coefficient can be determined. Subsequently, the load reduction callback time correction coefficient and the callback time setting value are input into the tenth multiplier 780, and the load reduction callback time correction value can be obtained through multiplication operation.

[0118] In addition, if Figure 10 As shown, the load increase reference rate correction value, the load decrease reference rate correction value and the selection enable signal in the load decrease state will be input into the second selection operator 790, and the reference feedforward rate correction value will be output after the second selection operator 790. Specifically, in the load decrease state, the reference feedforward rate correction value is equal to the load decrease reference rate correction value, otherwise, the reference feedforward rate correction value is equal to the load increase reference rate correction value.

[0119] like Figure 10 As shown, the load-up callback time correction value, the load-down callback time correction value, and the selection enable signal in the load-down state will be input into the third selection operator 7100, and the callback time correction value will be output after the third selection operator 7100. Specifically, in the load-down state, the callback time correction value is equal to the load-down callback time correction value; otherwise, the callback time correction value is equal to the load-up callback time correction value.

[0120] In one embodiment, the feedforward control unit specifically includes:

[0121] The starting module is used to generate a feedforward starting amount according to a starting rate correction value, a starting amplitude correction value and a starting amount callback time correction value when receiving a load control instruction.

[0122] The reference quantity generating module is used to generate a feedforward reference quantity according to the load increase reference rate correction value and the load decrease reference rate correction value when receiving a load control instruction.

[0123] The callback module is used to sum the feedforward starting amount and the feedforward reference amount to obtain the feedforward superposition amount, and after entering the callback stage based on the state judgment result, the feedforward superposition amount is moved closer to the feedforward set amount corresponding to the load control instruction according to the load increase callback time correction value or the load decrease callback time correction value.

[0124] The switching module is used to switch the feedforward callback amount in the callback phase with the feedforward setting amount corresponding to the load control instruction to obtain the feedforward control amount.

[0125] The auxiliary control quantity correction module is used to correct the feedforward control quantity according to the preset auxiliary control quantity correction coefficient to obtain the corrected feedforward control quantity.

[0126] The control module is used to perform feedforward control on the thermal power unit according to the corrected feedforward control quantity.

[0127] In a specific implementation, the callback module determines to enter the callback phase based on the status judgment result, which specifically includes:

[0128] When the state judgment result is a variable load state, determining a first duration for the thermal power unit to be in the variable load state and a second duration for the feedforward reference quantity to act;

[0129] If the first duration is greater than or equal to the second duration, it is determined to enter the callback phase.

[0130] like Figure 11 As shown, the first duration of the thermal power unit in the variable load state, that is, the variable load time, can be obtained by the first delay device 801 and the timer 802. Specifically, the steady-state signal and the set time signal (for example, 2s) are used as input data of the first delay device 801, and the timing reset signal output by the first delay device 801 is input into the timer 802. At the same time, the timing enable signal in the variable load state is input into the timer 802, and the timer 802 outputs the variable load time, that is, the first duration.

[0131] like Figure 12As shown, the second duration of the feedforward reference quantity, that is, the feedforward reference quantity action time, can be obtained by the fourth divider 803. Specifically, the load change and the reference rate correction value are input into the fourth divider 803, and the load change is divided by the reference rate correction value to obtain the feedforward reference quantity action time, that is, the second duration.

[0132] like Figure 13 As shown, the feedforward control unit can be specifically implemented by a third comparator 804, a second rate limiter 805, a third delay 806, an adder 807, a fourth selection operator 808, a fifth selection operator 809, a first first-order inertia module 810, a second subtractor 811, a second AND operator 812, an RS trigger 813, a sixth selection operator 814, an auxiliary control quantity controller 815, an auxiliary control quantity hand operator 816, a seventh selection operator 817, a second first-order inertia module 818 and an eleventh multiplier 819.

[0133] In practical applications, the corrected feedforward control quantity can provide accurate feedforward quantity for control systems such as boiler master control, feedwater master control, total air volume control and primary air control.

[0134] Figure 14 The feedforward control quantity generation curve diagram in one case is shown as an example. Figure 14 As shown, t0 represents the start time of the variable load state, t1 represents the time when the feedforward superposition amount reaches the maximum amount during the variable load period, t2 represents the time when the feedforward superposition amount reaches the callback stage and is equal to the corresponding value of the load control instruction, the time interval from t0 to t1 represents the growth stage of the feedforward control amount, the time interval from t1 to t2 represents the callback stage of the feedforward amount, and the time interval from t2 to t3 represents the overlap stage of the load control instruction.

[0135] In one embodiment, when the auxiliary control variable is the main steam pressure, the auxiliary control variable correction coefficient can be dynamically determined according to the load state.

[0136] Specifically, when the load state is in a steady state, the auxiliary control amount correction coefficient takes a value of 1.

[0137] When the load state is in a variable load state, the auxiliary control quantity correction coefficient can be closed-loop adjusted according to the deviation of the auxiliary control quantity, and the auxiliary control quantity correction coefficient is within the numerical range of 0.8 to 1.2.

[0138] When the variable load state ends, the auxiliary control correction coefficient is slowly adjusted from the current value to 1 according to the preset adjustment time.

[0139] Through the above-mentioned dynamic adjustment strategy of the auxiliary control correction coefficient, the value of the auxiliary control correction coefficient can be dynamically adjusted according to the actual scenario, thereby providing a more accurate data basis for the correction of the feedforward control quantity.

[0140] It is not difficult to see that this embodiment, by introducing a callback and switching scheme, achieves a disturbance-free switching between the feedforward callback variable and the load control command. This not only avoids disturbances during the switching process, but also significantly improves system stability, significantly reduces system overshoot, and ensures the stable operation of the thermal power unit under load changes. Through the auxiliary control variable correction link, the feedforward control variable is further corrected, thereby achieving efficient coordinated control of multiple control loops. This comprehensive coordinated control capability significantly improves the overall operating efficiency of the thermal power unit. By optimizing the feedforward variable generation mechanism and parameter correction strategy, the generation of overshoot is effectively suppressed.

[0141] In summary, the feedforward control system of the thermal power unit provided in this embodiment provides accurate feedforward control quantities for control systems such as the boiler master control, feedwater master control, total air volume control, and primary air control without affecting the controllability and operability of the thermal power unit. Through the multi-parameter comprehensive correction mechanism, the accuracy of the feedforward control can be effectively improved, and the load change requirements under different working conditions can be adapted. Through the synergistic effect of the state detection unit and the parameter generation unit, the control performance is further optimized, the response speed and adjustment accuracy of the thermal power unit are improved, and the feedforward control system of the entire thermal power unit can respond quickly to load changes. It can also adapt to different load segments and coal quality changes through the optimized feedforward control strategy, significantly improving the unit's adaptability to large-scale new energy access.

[0142] Based on the same general inventive concept, the present invention also protects a feedforward control method for a thermal power unit. The feedforward control method for a thermal power unit provided by the present invention is described below. The feedforward control method for a thermal power unit described below and the feedforward control system for a thermal power unit described above can be referred to each other.

[0143] like Figure 15 As shown, the feedforward control method for a thermal power plant provided in an embodiment of the present invention can be implemented based on the feedforward control system for a thermal power plant provided in the above embodiments. The above method mainly includes the following steps:

[0144] Step 910: Obtain operating parameters of the thermal power unit through a data acquisition unit.

[0145] Step 920: Determine the critical calorific value and boiler design efficiency of the thermal power unit based on the operating parameters through the correction calculation unit, and calculate the boiler efficiency correction coefficient based on the critical calorific value and boiler design efficiency.

[0146] Step 930: Generate a load control instruction according to the load setting value and load change rate setting value of the thermal power unit through the state detection unit, and judge the operating state of the thermal power unit to obtain a state judgment result.

[0147] Step 940: Determine the correction values of various parameters of the thermal power unit according to the boiler efficiency correction coefficient and the state judgment result through the parameter generation unit.

[0148] Step 950: The feedforward control unit generates and corrects the feedforward control quantity according to the load control instruction, the state judgment result and the correction values of various parameters, and performs feedforward control on the thermal power unit according to the corrected feedforward control quantity.

[0149] Regarding the method in the above embodiment, the specific implementation principle of each step has been described in detail in the embodiment of the system, and will not be further elaborated here.

[0150] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A feedforward control system for a thermal power unit, characterized in that: include: Data acquisition unit, used to obtain the operating parameters and load setting parameters of the thermal power unit; a correction calculation unit, configured to determine a key calorific value and a boiler design efficiency of the thermal power unit according to the operating parameters, and calculate a boiler efficiency correction coefficient according to the key calorific value and the boiler design efficiency; A state detection unit is used to generate a load control instruction according to the load setting parameter, and to judge the operating state of the thermal power unit to obtain a state judgment result; a parameter generating unit, configured to determine correction values of various parameters of the thermal power unit according to the boiler efficiency correction coefficient and the state judgment result; A feedforward control unit is used to generate and correct a feedforward control quantity according to the load control instruction, the state judgment result and the multiple parameter correction values, and perform feedforward control on the thermal power unit according to the corrected feedforward control quantity.

2. The feedforward control system of a thermal power plant according to claim 1, characterized in that: The operating parameters include: main steam temperature, main steam pressure, main steam flow, feed water temperature, feed water pressure, feed water flow, active power and actual coal quantity; The key calorific values include: main steam heat, feed water heat and coal calorific value.

3. The feedforward control system of a thermal power plant according to claim 2, characterized in that: The correction calculation unit includes: a first calculation module, configured to determine a main steam enthalpy value according to the main steam temperature and the main steam pressure, and multiply the main steam flow rate by the main steam enthalpy value to obtain a main steam heat; a second calculation module, configured to determine a feedwater enthalpy value based on the feedwater temperature and the feedwater pressure, and multiply the feedwater flow rate by the feedwater enthalpy value to obtain a feedwater heat value; a third calculation module, configured to generate a design coal quantity based on the active power and a preset boiler design coal quantity curve, calculate the quotient of the design coal quantity and the actual coal quantity to obtain a coal quantity ratio, and multiply the coal quantity ratio by the design calorific value of the coal type to obtain the calorific value of the coal; and generate a boiler design efficiency based on the active power and a preset boiler design efficiency curve; The fourth calculation module is used to calculate the boiler efficiency correction coefficient based on the main steam heat, feed water heat, coal calorific value and boiler design efficiency.

4. The feedforward control system of a thermal power plant according to claim 3, characterized in that: The fourth calculation module calculates the boiler efficiency correction factor based on the main steam heat, feed water heat, coal calorific value, and boiler design efficiency, including: Subtract the main steam heat from the feed water heat to calculate the working medium absorption heat; The actual efficiency of the boiler is calculated by dividing the heat absorbed by the working medium by the calorific value of the coal; The boiler efficiency correction coefficient is calculated by dividing the boiler design efficiency by the boiler actual efficiency.

5. The feedforward control system of a thermal power plant according to claim 1, characterized in that: The parameter generation unit includes: A first generating module is configured to use the boiler efficiency correction coefficient at the current moment as the efficiency correction holding value when the state judgment result is a variable load state; The second generating module is used to generate parameter correction values corresponding to each parameter setting value according to the efficiency correction maintaining value and a plurality of preset parameter setting values.

6. The feedforward control system of a thermal power plant according to claim 5, characterized in that: The multiple parameter setting values include: a starting rate standard value, a starting amplitude standard value, a starting callback time standard value, a load change rate setting value, and a callback time setting value; The second generation module includes: The first submodule is configured to multiply the efficiency correction hold value by the startup rate standard value, the startup amplitude standard value, and the startup callback time standard value, respectively, to obtain a startup rate correction value, a startup amplitude correction value, and a startup amount callback time correction value; A second submodule is configured to determine a load increase reference rate correction coefficient based on the efficiency correction hold value and a preset load increase reference rate correction curve, and multiply the load reference rate correction coefficient by a load change rate setting value to obtain a load increase reference rate correction value; A third submodule is configured to determine a load reduction reference rate correction coefficient based on the efficiency correction hold value and a preset load reduction reference rate correction curve, and multiply the load reduction reference rate correction coefficient by a load change rate setting value to obtain a load reduction reference rate correction value; a fourth submodule, configured to determine a load-increase callback time correction coefficient based on the efficiency correction hold value and a preset load-increase callback time correction curve, and multiply the load-increase callback time correction coefficient by a callback time setting value to obtain a load-increase callback time correction value; The fifth submodule is used to determine the load reduction callback time correction coefficient based on the efficiency correction holding value and the preset load reduction callback time correction curve, and multiply the load reduction callback time correction coefficient by the callback time setting value to obtain the load reduction callback time correction value.

7. The feedforward control system of a thermal power plant according to claim 6, characterized in that: The feedforward control unit comprises: a starting module, configured to generate a feedforward starting amount according to the starting rate correction value, the starting amplitude correction value, and the starting amount callback time correction value upon receiving the load control instruction; a reference quantity generating module, configured to generate a feedforward reference quantity according to the load increase reference rate correction value and the load decrease reference rate correction value upon receiving the load control instruction; a callback module, configured to sum the feedforward starting amount and the feedforward reference amount to obtain a feedforward superposition amount, and, after determining that a callback phase has begun according to the state judgment result, to move the feedforward superposition amount closer to the feedforward set amount corresponding to the load control instruction according to the load increase callback time correction value or the load decrease callback time correction value; A switching module, configured to switch the feedforward callback amount in the callback phase with the feedforward set amount corresponding to the load control instruction to obtain a feedforward control amount; an auxiliary control quantity correction module, configured to correct the feedforward control quantity according to a preset auxiliary control quantity correction coefficient to obtain a corrected feedforward control quantity; The control module is used to perform feedforward control on the thermal power unit according to the corrected feedforward control quantity.

8. The feedforward control system of a thermal power plant according to claim 7, characterized in that: The callback module determines to enter the callback phase according to the status judgment result, including: When the state judgment result is a variable load state, determining a first duration for the thermal power unit to be in the variable load state and a second duration for the feedforward reference amount to act; If the first duration is greater than or equal to the second duration, it is determined that the callback phase has begun.

9. The feedforward control system of a thermal power plant according to claim 7, characterized in that: When the auxiliary control amount is the main steam pressure, the auxiliary control amount correction coefficient is dynamically determined according to the load state; When the load state is in a steady state, the auxiliary control amount correction coefficient is 1; When the load state is in a variable load state, the auxiliary control amount correction coefficient is set to a value of 0.8 to 1.2; When the variable load state ends, the auxiliary control value correction coefficient is adjusted from the current value to 1 according to the preset adjustment time.

10. A feedforward control method for a thermal power unit, characterized in that: The method is based on the feedforward control system of a thermal power unit according to any one of claims 1 to 9, and the method comprises: Obtaining the operating parameters and load setting parameters of the thermal power unit through the data acquisition unit; Determining the critical calorific value and boiler design efficiency of the thermal power unit based on the operating parameters through a correction calculation unit, and calculating a boiler efficiency correction coefficient based on the critical calorific value and the boiler design efficiency; Generate a load control instruction according to the load setting parameter through the state detection unit, and judge the operating state of the thermal power unit to obtain a state judgment result; Determining, by a parameter generating unit, various parameter correction values of the thermal power unit according to the boiler efficiency correction coefficient and the state judgment result; The feedforward control unit generates and corrects the feedforward control quantity according to the load control instruction, the state judgment result and the multiple parameter correction values, and performs feedforward control on the thermal power unit according to the corrected feedforward control quantity.

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