CN101718427B - Control system of main steam pressure of large boiler - Google Patents

Abstract

The invention discloses a control system for the main steam pressure of a large boiler, which belongs to the automatic control system of a power station boiler circuit, and solves the technical problem of dynamic tracking and stable control of the main steam pressure of a large boiler. Including PID module, boiler unit, A/D changer, D/A converter and main steam pressure sensor of the boiler, using the function module, differential module, multiplication module, high value monitoring module and low plant monitoring in the distributed control system Module and analog switching module tower built a three-dimensional real-time online optimizer, intervening in the existing PID closed-loop control system of the boiler, forming an independent closed-loop control system of dynamic tracking and stable control, which solves the dynamic problem of the main steam pressure of large boilers The technical problem of tracking and stable control can improve the thermal economic index of the boiler and achieve the purpose of energy saving and emission reduction.

Description

A Control System of Main Steam Pressure of Large Boiler

technical field

The invention relates to an automatic control system, in particular to a PID automatic control system of a large-scale utility boiler.

Background technique

The control of the main steam pressure of the existing large-scale power plant boiler is basically completed by the PID automatic control system with fixed parameters. With the change of boiler load and the influence of other disturbance factors, the dynamic characteristics of the main steam pressure of large boilers are very different. Since the PID automatic control system with fixed parameters cannot adapt to the large-scale changes in the dynamic characteristics of the controlled object, resulting in large boiler main The control performance of the steam pressure decreases, and even fails to meet the requirements of the control index, which directly affects the stable and economical operation of the boiler.

Contents of the invention

The control system of the main steam pressure of a large boiler provided by the invention can adjust the PID parameters in time according to the change of the dynamic characteristics of the main steam pressure, and solves the technical problem of dynamic follow-up and stable control of the main steam pressure of the large boiler.

The present invention solves the above problems through the following solutions:

A control system for the main steam pressure of a large-scale boiler, including a PID module, a boiler unit, an A/D converter, a D/A converter, and a main steam pressure sensor of the boiler. The power generation command P ₀ of the boiler unit is connected to the A/ The input terminal i ₁ of the D converter, the output terminal of the main steam pressure sensor of the boiler is connected with the input terminal i ₂ of the A/D converter, and the output terminal o ₂ of the A/D converter is connected with The negative input terminals of the subtraction module are connected together, the output terminal _o1 of the A/D converter is connected together with the input terminal of the first function module f ₀ (x), and the first function module f ₀ (x) The output end is connected with the positive input end of the subtraction module, and the deviation E between the main steam pressure p _T and its set value p ₀ is obtained at the output end of the subtraction module, and the deviation E is respectively related to the high The input end of the value monitor 8 and the input end of the low value monitor 9 are connected together, and the output end of the high value monitor 8 is respectively connected with the control terminal s of the first analog switch module 1 and the third analog switch module 3 The control terminals s are connected together, and the output terminals of the low value monitor 9 are respectively connected with the control terminal s of the second analog switch module 2 and the control terminal s of the fourth analog switch module 4; the main steam pressure p _T is connected with The deviation E between the set values _{p 0} also passes through a differential module to obtain the change speed E _c of the deviation E, which is respectively input to the input terminal of the tenth function module f ₂₂ (x), the first The input end of the ninth function module f ₂₃ (x), the input end of the eighth function module f ₂₄ (x), the input end of the seventh function module f ₁₂ (x), the input end of the sixth function module f ₁₃ (x) , the input terminal of the fifth function module f ₁₄ (x), the output terminal of the sixth function module f ₁₃ (x) is connected to the input terminal i ₁ of the first analog switch module 1, and the seventh function module f ₁₂ (x ) is connected to the input terminal _i2 of the first analog switch module 1, the output terminal o of the first analog switch module 1 is connected to the input terminal i2 of the second analog switch module ₂ , and the fifth function The output terminal of the module f ₁₄ (x) is connected to the input terminal i ₁ of the second analog switch module 2, and the boiler load command P ₀ after analog-to-digital conversion is respectively connected to the input of the second function module f ₁₁ (x) terminal, the input terminal of the third function module f ₂₁ (x), the input terminal of the fourth function module f ₃₁ (x), the output terminal of the second function module f ₁₁ (x) is connected to an input terminal of the first multiplication module Together, the output end of the second analog switch module 2 is connected with the other input end of the first multiplication module 5, and the output end of the first multiplication module 5 is connected with the proportional band adjustment parameter of the PID module in the boiler automatic control system The input terminals of δ are connected together; the output terminal of the ninth function module f ₂₃ (x) is connected with the input terminal i ₁ of the third analog switch module 3, and the input terminal of the tenth function module f ₂₂ (x) is connected with the input terminal of the third analog switch module 3 Three analog switches The input terminal _i2 of module 3 is connected, the output terminal o of the third analog quantity switch module 3 is connected with the input terminal _i2 of the fourth analog quantity switch module 4, and the output terminal of the eighth function module _f24 (x) is connected with The input terminal _i1 of the fourth analog switch module 4 is connected together, the output terminal of the fourth analog switch module 4 is connected with an input terminal of the second multiplication module 6, and the other input terminal of the second multiplication module 6 is connected with the first input terminal of the second multiplication module 6. The output terminals of the three function modules f ₂₁ (x) are connected together, and the output terminals of the second multiplication module 6 are connected together with the input terminals of the integral time adjustment parameter T _i of the PID module in the boiler automatic control system; the fourth analog quantity The output terminal of the switch module 4 is connected together with the input terminal of the eleventh function module f ₃₂ (x), and the output terminal of the eleventh function module f ₃₂ (x) is connected together with the input terminal of the third multiplication module 7, The other input end of the third multiplication module 7 is connected with the output end of the fourth function module f ₃₁ (x), and the output end of the third multiplication module 7 is connected with the differential time adjustment parameter T of the PID module in the boiler automatic control system The inputs of _d are connected together.

A multiplication module is connected between the output terminal of the first multiplication module 5 and the input terminal of the proportional band adjustment parameter δ of the PID module in the boiler automatic control system, and the output terminal of the second multiplication module 6 is connected with the PID module in the boiler automatic control system A multiplication module is connected between the input terminals of the integral time adjustment parameter T _i , and a multiplication module is connected between the output end of the third multiplication module 7 and the input end of the differential time adjustment parameter T _d of the PID module in the boiler automatic control system . These multiplication modules are respectively multiplied with the fixed value δ ₀ of the proportional band of the original fixed parameter PID adjustment module, the fixed value T _i0 of the integral time, and the fixed value T _d0 of the differential time.

The invention solves the technical problem of dynamic follow-up and stable control of the main steam pressure of a large boiler, can improve the thermal economy index of the boiler and achieve the purpose of energy saving and emission reduction.

Description of drawings:

Fig. 1 is a schematic diagram of the circuit structure of the present invention

Figure 2 is a schematic diagram of the circuit structure of a three-dimensional real-time online optimizer

Figure 3 is a list of the characteristics and parameters of the modules used in the 3D real-time online optimizer

Detailed ways

Firstly, set the function module characteristics of the first to eleventh function modules according to the list shown in FIG. 3 .

A control system for the main steam pressure of a large-scale boiler, including a PID module, a boiler unit, an A/D converter, a D/A converter, and a main steam pressure sensor of the boiler. The power generation command P ₀ of the boiler unit is connected to the A/ The input terminal i ₁ of the D converter, the analog output terminal of the main steam pressure sensor of the boiler is connected with the input terminal i ₂ of the A/D converter, and the output terminal o ₂ of the A/D converter It is connected together with the negative input terminal of the subtraction module, and the output terminal _o1 of the A/D converter is connected together with the input terminal of the first function module f ₀ (x), and the first function module f ₀ (x) The output end of the subtraction module is connected together with the positive input end of the subtraction module, and the deviation E between the main steam pressure p _T and its set value p ₀ is obtained at the output end of the subtraction module, and the deviation E is respectively related to The input end of the high-value monitor 8 and the input end of the low-value monitor 9 are connected together, and the output end of the high-value monitor 8 is respectively connected with the control terminal s of the first analog switch module 1 and the third analog switch module 3 The control terminals s of the low value monitor 9 are connected together with the control terminal s of the second analog switch module 2 and the control terminal s of the fourth analog switch module 4 respectively; the main steam pressure p _T The deviation E between its set value p ₀ also passes through a differential module to obtain the change speed _Ec of the deviation E, which is respectively input to the input terminals of the tenth function module f ₂₂ (x) _, The input terminal of the ninth function module f ₂₃ (x), the input terminal of the f ₂₄ (x) function module, the input terminal of the seventh function module f ₁₂ (x); the input terminal of the sixth function module f ₁₃ (x), The input terminal of the fifth function module f ₁₄ (x), the output terminal of the sixth function module f ₁₃ (x) is connected to the input terminal i ₁ of the first analog switch module 1, and the seventh function module f ₁₂ (x) The output terminal of the first analog quantity switch module 1 is connected to the input terminal _i2 , the output terminal o of the first analog quantity switch module 1 is connected to the input terminal i2 of the second analog quantity switch module ₂ , and the fifth function module The output end of f ₁₄ (x) is connected to the input end i ₁ of the second analog switch module 2, and the power command P ₀ of the boiler unit after analog-to-digital conversion is respectively input to the second function module f ₁₁ (x) Input end, the input end of the third function module f ₂₁ (x), the input end of the fourth function module f ₃₁ (x), the output end of the second function module f ₁₁ (x) and an input of the first multiplication module 5 The terminals are connected together, the output terminal of the second analog switch module 2 is connected with the other input terminal of the first multiplication module 5, the output terminal of the first multiplication module 5 is connected with the proportional band of the PID module in the boiler automatic control system The input terminals of the adjustment parameter δ are connected together; the output terminal of the ninth function module f ₂₃ (x) is connected with the input terminal i ₁ of the third analog switch module 3, and the input terminal of the tenth function module f ₂₂ (x) with the third The input terminal _i2 of the analog switch module 3 is connected, the output terminal o of the third analog switch module 3 is connected with the input terminal _i2 of the fourth analog switch module 4, and the eighth function module _f24 (x) The output terminal is connected together with the input terminal _i1 of the fourth analog switch module 4, the output terminal of the fourth analog switch module 4 is connected together with an input terminal of the second multiplication module 6, and the other input terminal of the second multiplication module 6 terminal is connected together with the output terminal of the third function module f ₂₁ (x), and the output terminal of the second multiplication module 6 is connected together with the input terminal of the integral time adjustment parameter T _i of the PID module in the boiler automatic control system; The output terminals of the four analog switch modules 4 are simultaneously connected to the input terminals of the eleventh function module f ₃₂ (x), and the output terminals of the eleventh function module f ₃₂ (x) are connected to the input terminals of the third multiplication module 7 Together, the other input end of the third multiplication module 7 is connected with the output end of the fourth function module f ₃₁ (x), and the output end of the third multiplication module 7 is connected with the differential time of the PID module in the boiler automatic control system The inputs of the adjustment parameter T _d are connected together.

A multiplication module is connected between the output terminal of the first multiplication module 5 and the input terminal of the proportional band adjustment parameter δ of the PID module in the boiler automatic control system, and the output terminal of the second multiplication module 6 is connected with the PID module in the boiler automatic control system A multiplication module is connected between the input terminals of the integral time adjustment parameter T _i , and a multiplication module is connected between the output end of the third multiplication module 7 and the input end of the differential time adjustment parameter T _d of the PID module in the boiler automatic control system . These multiplication modules are respectively multiplied with the fixed value δ ₀ of the proportional band of the original fixed parameter PID adjustment module, the fixed value T _i0 of the integral time, and the fixed value T _d0 of the differential time.

Claims (2)

1. A control system for large-scale boiler main steam pressure, comprising a main steam pressure sensor of a PID module, boiler unit, A/D converter, D/A converter and boiler, characterized in that: the generating power of said boiler unit The instruction P ₀ is connected to the input terminal i ₁ of the A/D converter, the analog output terminal of the main steam pressure sensor of the boiler is connected to the input terminal i ₂ of the A/D converter, and the A/D The output terminal _o2 of the converter is connected together with the negative input terminal of the subtraction module, the output terminal _o1 of the A/D converter is connected together with the input terminal of the first function module _f0 (x), and the first The output terminal of the function module f ₀ (x) is connected with the positive input terminal of the subtraction module, and the difference between the main steam pressure p _T and the main steam pressure set value p ₀ is obtained at the output terminal of the subtraction module. The deviation E between, this deviation E is connected together with the input terminal of the high value monitor (8) and the input terminal of the low value monitor (9) respectively, the output terminal of the high value monitor (8) is respectively connected with the first simulation The control terminal s of the quantity switch module (1) and the control terminal s of the third analog quantity switch module (3) are connected together, and the output terminal of the low value monitor (9) is respectively connected with the second analog quantity switch module (2) The control terminal s and the control terminal s of the fourth analog switch module (4) are connected together; the deviation E between the main steam pressure p _T and its set value p ₀ is also passed through a differential module to obtain the change speed E of the deviation E _c , the change speed E _c of the deviation E is respectively input to the input terminal of the tenth function module f ₂₂ (x), the input terminal of the ninth function module f ₂₃ (x), and the input terminal of the eighth function module f ₂₄ (x) terminal, the input terminal of the seventh function module f ₁₂ (x), the input terminal of the sixth function module f ₁₃ (x), the input terminal of the fifth function module f ₁₄ (x), the sixth function module f ₁₃ (x) The output terminal of the first analog quantity switch module (1) is connected to the input terminal _i1 , and the output terminal of the seventh function module _f12 (x) is connected to the input terminal _i2 of the first analog quantity switch module (1) , the output terminal o of the first analog switch module (1) is connected to the input terminal _i2 of the second analog switch module (2), and the output terminal of the fifth function module f ₁₄ (x) is connected to the second analog switch module The input terminal _i1 of the module (2) is connected to each other, and the power generation command P ₀ of the boiler unit after the analog-to-digital conversion is respectively input to the input terminal of the second function module f ₁₁ (x), and the third function module f ₂₁ (x) The input end of the fourth function module f ₃₁ (x), the output end of the second function module f ₁₁ (x) is connected with an input end of the first multiplication module (5), and the second analog switch The output end of the module (2) is connected together with the other input end of the first multiplication module (5), and the output end of the first multiplication module (5) is connected with the proportional band adjustment parameter δ of the PID module in the boiler automatic control system. The input terminals are connected together; the ninth function module f ₂₃ ( The output terminal of x) is connected to the input terminal _i1 of the third analog switch module (3), and the output terminal of the tenth function module _f22 (x) is connected to the input terminal _i2 of the third analog switch module (3). The output terminal o of the third analog switch module (3) is connected with the input terminal i ₁ of the fourth analog switch module (4), and the output terminal of the eighth function module f ₂₄ (x) is connected with the fourth analog The input terminals i to ₂ of the quantity switch module (4) are connected together, the output terminal of the fourth analog quantity switch module (4) is connected together with an input terminal of the second multiplication module (6), and the other of the second multiplication module (6) One input terminal is connected with the output terminal of the third function module f ₂₁ (x), and the output terminal of the second multiplication module (6) is connected with the input terminal of the integral time adjustment parameter T _i of the PID module in the boiler automatic control system together; the output terminal of the fourth analog switch module (4) is connected together with the input terminal of the eleventh function module f ₃₂ (x) at the same time, and the output terminal of the eleventh function module f ₃₂ (x) is connected with the third multiplication The input terminals of the module (7) are connected together, the other input terminal of the third multiplication module (7) is connected together with the output terminal of the fourth function module f ₃₁ (x), and the output terminal of the third multiplication module (7) It is connected with the input end of the differential time adjustment parameter T _d of the PID module in the boiler automatic control system. 2. the control system of large boiler main steam pressure according to claim 1 is characterized in that: the input end of the output end of the first multiplication module (5) and the proportional band adjustment parameter δ of the PID module in the boiler automatic control system A multiplication module is connected between them, and a multiplication module is connected between the output terminal of the second multiplication module (6) and the input end of the integral time adjustment parameter T _i of the PID module in the boiler automatic control system, and the third multiplication module (7) A multiplication module is connected between the output terminal of the boiler automatic control system and the input terminal of the differential time adjustment parameter T _d of the PID module in the boiler automatic control system.

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