FPGA-based biomass unit power quality and unit efficiency measurement and control system

Abstract

The present invention relates to a biomass unit power quality and unit efficiency measurement and control system based on FPGA, comprising a sampling module, a main control module and a host computer connected in sequence, wherein the sampling module is connected to the steam turbine to be measured, and is used to collect the steam turbine signal; the main control module obtains the exhaust enthalpy value and the economic index value according to the iterative solution of the steam turbine signal, and generates a control instruction for regulating the working state of the steam turbine to be measured based on the exhaust enthalpy value and the economic index value, so as to realize the optimization control of the steam turbine to be measured, and the main control module includes an FPGA development board; the host computer and the main control module realize information exchange. Compared with the prior art, the present invention has the advantages of being more accurate and efficient.

Description

Technical Field

[0001] The invention belongs to the field of renewable energy power generation, and relates to a biomass unit monitoring and debugging system, and in particular to a biomass unit power quality and unit efficiency measurement and control system based on FPGA. Background Art

[0002] As a renewable energy, biomass energy has better stability than other energy sources such as wind energy and tidal energy. However, due to the different combustion values ​​of the fuels it uses, it still has certain defects in stability compared to traditional thermal power. Nowadays, there are more and more biomass power plants, and the primary problem has become how to effectively monitor the power quality of biomass units and adjust the units when the power is unstable, so as to quickly adjust the power generation stability of biomass power plants.

[0003] The existing use of 51 single-chip microcomputers to measure, control and improve the power quality of biomass units still has great limitations, such as slow computing speed, unprotected chips and easy damage. Nowadays, the power grid has higher and higher requirements for system stability. Under the framework of smart grid, many new energy sources have been integrated into the power grid, which requires the adaptability and controllability of the units to be higher. Traditional data processors are increasingly unable to meet the requirements, and their effect on improving system performance has slowed down, affecting system stability. Summary of the invention

[0004] The purpose of the present invention is to overcome the problems of hardware instability and low computing power in the above-mentioned prior art and to provide a more accurate and efficient FPGA-based biomass unit power quality and unit efficiency measurement and control system.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A biomass unit power quality and unit efficiency measurement and control system based on FPGA includes a sampling module, a main control module and a host computer connected in sequence, wherein:

[0007] The sampling module is connected to the steam turbine to be tested and is used to collect steam turbine signals;

[0008] The main control module obtains the exhaust enthalpy value and the economic index value according to the iterative solution of the steam turbine signal, generates a control instruction for controlling the working state of the steam turbine to be tested based on the exhaust enthalpy value and the economic index value, and realizes the optimized control of the steam turbine to be tested, and the main control module includes an FPGA development board;

[0009] The host computer realizes information exchange with the main control module.

[0010] Furthermore, the sampling module includes a voltage and current sampling circuit, a power sampling circuit and a frequency sampling circuit.

[0011] Furthermore, the main control module also includes an Ethernet PHY chip connected to the FPGA development board.

[0012] Furthermore, the FPGA development board is also connected to an RJ45 interface with an isolator.

[0013] Furthermore, the main control module also includes a FLASH chip connected to the FPGA development board.

[0014] Furthermore, the host computer and the main control module communicate using the ARP protocol.

[0015] Furthermore, the exhaust enthalpy value is obtained by thermal power balance calculation.

[0016] Furthermore, the control instruction is generated based on the exhaust enthalpy value as follows:

[0017] 101) determining in sequence whether each section of steam is in the wet steam zone, and performing the next step for each section in the wet steam zone;

[0018] 102) obtaining the enthalpy value of each segment based on the curve fitting of each segment;

[0019] 103) Perform heat power balance calculation based on the enthalpy value of each point to obtain the exhaust enthalpy value of the time;

[0020] 104) Determine whether |h is satisfied c1 -h c2 |≤ε,h c1 is the solution value of the last iteration, h c2 is the solution value of this iteration, ε is the set threshold, if yes, execute step 105), if no, add the known enthalpy value to the curve fitting enthalpy value to obtain a new enthalpy value, and return to step 103);

[0021] 105) Generate control instructions based on the latest exhaust enthalpy value.

[0022] Furthermore, the economic indicators include the cylinder efficiency and thermal efficiency of the steam turbine, which are calculated using the counter-balance method.

[0023] Furthermore, the control instructions generated based on the economic index value are specifically:

[0024] 201) Obtaining the main steam flow rate D0 based on the turbine signal calculation;

[0025] 202) Determine whether |D0-D′0|≤ε is satisfied, where D′0 is the main steam flow obtained in the last iteration and ε is the set threshold value. If yes, execute step 203), if not, set D0=D′0 and return to step 201);

[0026] 203) Calculate various economic indicators;

[0027] 204) Calculate the turbine power P c ;

[0028] 205) Determine the turbine power P c Is it equal to the rated power P0? If not, a control command is generated until the turbine power P c Equal to the rated power P0.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. The present invention can complete the adjustment of the unit in a very short time, realize timely adjustment of the unit fluctuations that occur during the operation and grid connection of the biomass power plant, and improve the economy of the unit. In the long run, the annual biomass power plant is relatively long, and the improvement of the economy can save a lot of expenses for the power plant. At the same time, it solves the biggest hidden danger, that is, the unstable operation of the unit when the unit is connected to the grid, so that it can resume normal operation in the shortest time and reduce economic losses. The present invention solves the problems of voltage, current, active and reactive power adjustment of the generator set when the biomass power plant generates electricity and is connected to the grid and when the power fluctuates during daily work, enhances the quality of electric energy, and reduces the impact on the power grid.

[0031] 2. Compared with traditional technologies, the monitoring reliability of the present invention is higher, the iterative simulation operation speed is faster, and the accuracy is higher. It plays an extremely important role in the stability of the new energy power grid. It overcomes the shortcomings of traditional technologies such as low monitoring reliability, untimely data transmission, and low system operation safety, and realizes reliable, safe, and real-time monitoring and improvement of the power quality of biomass generators.

[0032] 3. For biomass power generation, the FPGA used in the present invention achieves the advantage of efficient and stable improvement of its electric energy. FPGA has powerful parallel capability and strong reliability for multi-task processing, which reduces the impact on the power grid, greatly improves the accuracy, reliability and real-time performance of the power quality monitoring system, and regulates and improves the power quality. The embedded controller constructed by the FPGA chip of the present invention can take advantage of the advantages of the FPGA chip itself, such as parallel computing, greatly improving the control efficiency and accuracy of the control system, so as to achieve the purpose of reducing unit losses and controlling the output power quality of the unit.

[0033] 4. The present invention has an Ethernet PHY chip and uses Ethernet communication to transmit data, and transmits the collected data to the embedded system in real time and reliably, so that the power quality monitoring of the biomass generator is visualized.

[0034] 5. The present invention adopts an iterative method to perform real-time optimization in the control process, which takes the solution of unit stability to a further step. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the framework structure of the present invention;

[0036] Figure 2 It is the overall flow chart of the working process of the present invention;

[0037] Figure 3 This is the flow chart of unit power control based on exhaust enthalpy monitoring;

[0038] Figure 4 Calculate flow chart for economic indicators;

[0039] Figure 5 Adjust the flow chart for economy. DETAILED DESCRIPTION

[0040] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0041] like Figure 1 As shown, this embodiment provides a FPGA-based biomass unit power quality and unit efficiency measurement and control system, including a sampling module 1, a main control module 2 and a host computer 3 connected in sequence, the sampling module 1 is connected to the steam turbine to be tested, and is used to collect turbine signals, including voltage, current, power and frequency signals of the steam turbine to be tested; the main control module 2 obtains the exhaust enthalpy value and the economic index value according to the steam turbine signal, and generates a control instruction for controlling the working state of the steam turbine to be tested based on the exhaust enthalpy value and the economic index value, and uploads it to the host computer 3; the host computer 3 and the main control module 2 realize information exchange.

[0042] In this embodiment, the sampling module 1 includes a voltage and current sampling circuit 101 , a power sampling circuit 102 , and a frequency sampling circuit 103 .

[0043] The main control module 2 includes an FPGA development board. In this embodiment, the FPGA development board uses the FPGA development board of Altera Arria 10Gx660 of Intel Corporation, which works in AS mode (active serial configuration mode), sends a data read signal to the configurator EPCS, reads the data of EPCS into the FPGA, and realizes the control of the FPGA. The configuration data is sent to the FPGA through the DATA0 pin, and the configuration data is synchronized with the DCLK input, and 1 bit of data is transmitted in 1 clock cycle.

[0044] The main control module 2 also includes an Ethernet PHY chip connected to the FPGA development board. In this embodiment, the Ethernet PHY chip uses Marvell's Gigabit Ethernet PHY chip 88E1111-RCJ to achieve Ethernet transmission of the FPGA development board. The FPGA development board uses the ARP (Address Resolution Protocol) address resolution protocol to resolve the control request sent by the FPGA to the host computer and the signal transmitted by the host computer.

[0045] In a preferred embodiment, the FPGA development board is also connected to an RJ45 interface with an isolator.

[0046] The main control module 2 also includes a FLASH chip connected to the FPGA development board for storing system files to avoid data loss during power failure.

[0047] This embodiment can perform sampling, calculation, logic comparison and control operations on the unit based on the above-mentioned biomass unit power quality and unit efficiency measurement and control system. The following is mainly divided into four parts: communication and sampling, exhaust enthalpy detection, economic index calculation and economic adjustment.

[0048] 1. Communication and sampling: After obtaining the voltage and current at the unit output end of the voltage and current sampling circuit 101, compare it with the rated value, and establish the configuration management software (VFExplorer) to perform hardware signal transmission, channel configuration and bit number configuration for signal communication. The control domain includes FF fieldbus I / O module AM712, serial communication module COM741 supporting MOODBUS-RTU, PROFIBUS master communication module COM722, and bus (current, voltage, power, frequency) input module.

[0049] 2. Exhaust enthalpy monitoring: The exhaust enthalpy value reflects the stability of the unit power. The exhaust enthalpy is calculated by thermal power balance, and the heat balance calculation is performed on the entire heat recovery system. When the turbine operating condition is unstable, the power fluctuates. The detected exhaust enthalpy is compared with the exhaust enthalpy value required by the rated operating condition through heat balance calculation to gradually approach it. The heat balance equation is formula (1):

[0050]

[0051]

[0052] Where W is the internal power of the steam turbine; Ng is the generator power; η m is the mechanical efficiency; η g is the motor efficiency; D0 is the main steam flow rate; h0 is the main steam enthalpy; D rh is the hot resteam flow rate; q rh is the hot resteam enthalpy; D j is the air extraction volume at each level; h j is the enthalpy value at each level; D c is the exhaust volume; h c is the exhaust enthalpy value. Calculate the exhaust enthalpy value h c Iterate to satisfy |h c1 -h c2 |≤ε, the adjustment can be completed (h c1 is the solution value of the last iteration, h c2 is the solution value of this iteration, and ε is the set threshold).

[0053] The control diagram of exhaust enthalpy monitoring power improvement is as follows Figure 3 As shown, the specific description includes the following steps:

[0054] 101) determining in sequence whether each section of steam is in the wet steam zone, and performing the next step for each section in the wet steam zone;

[0055] 102) obtaining the enthalpy value of each segment based on the curve fitting of each segment;

[0056] 103) The enthalpy value of each point is transmitted to FPGA;

[0057] 104) Perform heat balance calculations;

[0058] 105) Obtain the exhaust enthalpy value of the time and determine whether it meets the requirement of |h c1 -h c2 |≤ε, if yes, execute step 106), if no, add the known enthalpy value to the curve fitting enthalpy value to obtain a new enthalpy value, and return to step 103);

[0059] 106) FPGA transmits commands to the host computer to control the unit improvement.

[0060] 3. Calculation of economic indicators

[0061] The general form of the heat balance equation of any unit thermal system is expressed as:

[0062]

[0063] Where i = 1…m, m is the number of heater stages, [a i ] is the heat recovery extraction coefficient, [a fi ] is the auxiliary gas coefficient, [a ti ] is the minimum water flow number, Δq is the unit heat of the heater, and [A] is the time-sharing value of the thermal system.

[0064] Substituting the pumping coefficients and pumping flow rates of each level returned by the system into formulas (4) and (5), we can obtain

[0065]

[0066] P c =P0(rated power) (5)

[0067] D0=3600·Ng / H0 (6)

[0068] η i =H0 / Q0 (7)

[0069] Among them, h n Denotes the enthalpy value at each point, D fj 、h fj They represent the iterative extraction volume and iterative exhaust enthalpy respectively. The monitored extraction coefficient a i And the suction volume D i , respectively substitute into the formula to solve the steam equivalent heat drop H0, boiler heat absorption Q0, check the main steam flow D0, and calculate the thermal efficiency η i . And compared with the rated thermal efficiency, the return value is entered into the main control to adjust the turbine system after logical judgment.

[0070] 4. Economic adjustment: For the steam turbine of a biomass power plant, the cylinder efficiency and thermal efficiency of the steam turbine are the main economic indicators of the steam turbine. In this embodiment, the counter-balance method is used for calculation:

[0071] High pressure cylinder efficiency

[0072] Medium pressure cylinder efficiency

[0073] Low pressure cylinder efficiency

[0074] Unit heat rate q = (D ms hms +D rh h rhh +D ma h ma -D fw h fw -D rc h rc -D sw h sw -D rw h rw ) / P c (11)

[0075] [kJ / kWh]

[0076] Unit thermal efficiency η j =3600 / q [%] (12)

[0077] Unit steam consumption rate d = D ms P pc [kJ / kWh] (13)

[0078] D ms , D rh , D rc , D rw , D ma They are main steam flow, hot resteam flow, cold resteam flow, reheating water and chemical make-up water [kJ / h] respectively; h ms 、h rhh are main steam enthalpy and reheat steam enthalpy [kJ / kg] respectively; h rhc , are respectively the high pressure cylinder exhaust enthalpy and the high pressure cylinder ideal exhaust enthalpy; They are the intake enthalpy, exhaust enthalpy and ideal exhaust enthalpy of the intermediate pressure cylinder [kJ / kg]; h r , are respectively the low pressure cylinder intake enthalpy, exhaust enthalpy and ideal exhaust enthalpy [kJ / kg]; P c is the generator power [kW]. After solving various parameters, the circuit where the FPGA is located adjusts various parameters of the generator turbine parameters to achieve optimal control of the unit.

[0079] In this embodiment, the economic calculation process is as follows: Figure 4 As shown, the following steps are included:

[0080] 201) The sampling module measures various working condition parameters;

[0081] 202) transmitting to FPGA for calculation;

[0082] 203) calculate and solve the exhaust port, high cylinder exhaust, exhaust pressure and corresponding group internal sales rate;

[0083] 204) obtaining the main steam flow rate D0;

[0084] 205) Determine whether |D0-D0′|≤ε is satisfied, where D0′ is the main steam flow obtained in the last iteration and ε is the set threshold value. If yes, execute step 206), if not, set D0=D0′ and return to step 202);

[0085] 206) Calculate various economic indicators;

[0086] 207) Output data to FPGA.

[0087] In this embodiment, the economic adjustment process is as follows: Figure 5 As shown, the following steps are included:

[0088] 301) The sampling module measures various working condition parameters;

[0089] 302) Calculate the parameters in the high-pressure cylinder, the parameters in the medium-pressure cylinder, the parameters in the low-pressure cylinder, the main steam flow, the hot resteam flow and the cold resteam flow, and calculate the heat rate and steam rate;

[0090] 303) Calculate the turbine power P c ;

[0091] 304) Determine the turbine power P c Is it equal to the rated power P0? If not, the FPGA will adjust the parameters until the turbine power P c Equal to the rated power P0.

[0092] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A biomass unit power quality and unit efficiency measurement and control system based on FPGA, characterized in that: It comprises a sampling module (1), a main control module (2) and a host computer (3) which are connected in sequence, wherein: The sampling module (1) is connected to the steam turbine to be tested and is used to collect steam turbine signals; The main control module (2) obtains the exhaust enthalpy value and the economic index value according to the iterative solution of the steam turbine signal, and generates a control instruction for controlling the working state of the steam turbine to be tested based on the exhaust enthalpy value and the economic index value, so as to realize the optimized control of the steam turbine to be tested. The main control module (2) includes an FPGA development board, and the exhaust enthalpy value is obtained by thermal power balance calculation. The economic index includes the cylinder efficiency and thermal efficiency of the steam turbine, which are calculated by the counter balance method; The host computer (3) realizes information interaction with the main control module (2); The control instruction generated based on the exhaust enthalpy value is specifically: 101) determining in sequence whether each section of steam is in the wet steam zone, and performing the next step for each section in the wet steam zone; 102) obtaining the enthalpy value of each segment based on the curve fitting of each segment; 103) Perform heat power balance calculation based on the enthalpy value of each point to obtain the exhaust enthalpy value of the time; 104) Determine whether |h is satisfied c1 -h c2 |≤ε,h c1 is the solution value of the last iteration, h c2 is the solution value of this iteration, ε is the set threshold, if yes, execute step 105), if no, add the known enthalpy value to the curve fitting enthalpy value to obtain a new enthalpy value, and return to step 103); 105) generating a control instruction based on the latest exhaust enthalpy value; The control instructions generated based on the economic index value are specifically: 201) Obtaining the main steam flow rate D0 based on the turbine signal calculation; 202) Determine whether |D0-D0′|≤ε is satisfied, where D0′ is the main steam flow obtained in the last iteration and ε is the set threshold value. If yes, execute step 203), if not, set D0=D0′ and return to step 201); 203) Calculate various economic indicators; 204) Calculate the turbine power P c ; 205) Determine the turbine power P c Is it equal to the rated power P0? If not, a control command is generated until the turbine power P c Equal to the rated power P0.

2. The FPGA-based biomass unit power quality and unit efficiency measurement and control system according to claim 1 is characterized in that: The sampling module (1) comprises a voltage and current sampling circuit (101), a power sampling circuit (102) and a frequency sampling circuit (103).

3. The FPGA-based biomass unit power quality and unit efficiency measurement and control system according to claim 1 is characterized in that: The main control module (2) also includes an Ethernet PHY chip connected to the FPGA development board.

4. The FPGA-based biomass unit power quality and unit efficiency measurement and control system according to claim 1 is characterized in that: The FPGA development board is also connected to an RJ45 interface with an isolator.

5. The FPGA-based biomass unit power quality and unit efficiency measurement and control system according to claim 1 is characterized in that: The main control module (2) also includes a FLASH chip connected to the FPGA development board.

6. The FPGA-based biomass unit power quality and unit efficiency measurement and control system according to claim 1 is characterized in that: The host computer (3) and the main control module (2) communicate with each other using the ARP protocol.

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