CN112596442A

CN112596442A - Gas wall-mounted boiler control system and control method thereof

Info

Publication number: CN112596442A
Application number: CN202011513793.9A
Authority: CN
Inventors: 武永华; 羊富贵; 张�浩; 张禹; 颜峰坡
Original assignee: Fujian Jiangxia University
Current assignee: Fujian Jiangxia University
Priority date: 2020-12-18
Filing date: 2020-12-18
Publication date: 2021-04-02

Abstract

The invention relates to a control system and a control method for a gas wall-mounted boiler. The device comprises a main control board and a sensor interface circuit connected with the main control board and used for transmitting a sensor acquisition signal, a relay driving circuit used for controlling a fan, a water pump and a three-way reversing valve, a flame detection circuit used for detecting ignition flame of the gas wall-mounted boiler, a pulse ignition circuit used for realizing ignition of the gas wall-mounted boiler, a display setting board used for realizing key input and display output, a proportional valve driving circuit used for realizing automatic constant water outlet temperature of the gas wall-mounted boiler, and a switching power supply circuit used for supplying power to the whole system. The invention can realize the automatic control of the gas wall-mounted boiler, and the whole system works stably.

Description

Gas wall-mounted boiler control system and control method thereof

Technical Field

The invention relates to a control system and a control method for a gas wall-mounted boiler.

Background

The wall-mounted gas stove is a household appliance for collecting heat and supplying domestic hot water, and is an essential facility for a future well-being type house. The wall-mounted gas stove adopts clean energy, can meet the requirement of environmental protection to the maximum extent, and is superior to other fuels such as coal or petroleum. In recent years, natural gas pipe networks in various cities, particularly large and medium cities, in China have been popularized basically, so that the gas wall-mounted boiler is widely applied to heating and hot water supply, and the gas wall-mounted boiler is rapidly exploded due to the characteristics of energy conservation, environmental protection and capability of meeting individual requirements of users, and becomes one of popular household electric products at present. The wall-mounted gas boiler will enter the development and growth stage along with the push of national policy of changing coal into gas.

Disclosure of Invention

The invention aims to provide a control system and a control method of a wall-mounted gas boiler, which can realize automatic control of the wall-mounted gas boiler and ensure that the whole system works stably.

In order to achieve the purpose, the technical scheme of the invention is as follows: the utility model provides a gas hanging stove control system, the sensor interface circuit who is used for transmitting sensor acquisition signal who is connected including the main control board and with this main control board, a relay drive circuit for controlling the fan, a water pump, the tee bend switching-over valve, a flame detection circuitry for detecting gas hanging stove ignition flame, a pulse ignition circuit for realizing gas hanging stove ignition, a display setting board for realizing key input, show output, a proportional valve drive circuit for realizing gas hanging stove goes out the automatic invariable of water temperature, and be used for the switching power supply circuit for whole device power supply.

In an embodiment of the present invention, the sensor interface circuit includes a wind pressure switch detection interface circuit, a water pressure switch detection interface circuit, an overheat protection interface circuit, a water flow sensor interface circuit, a bathroom/heating temperature detection interface circuit, and a room temperature detection interface circuit.

In an embodiment of the invention, the relay driving circuit comprises a fan output control circuit, a water pump output control circuit, a three-way reversing valve output control circuit and an electromagnetic valve output control circuit.

In an embodiment of the present invention, the relay driving circuit employs ULN 2003.

In one embodiment of the present invention, the flame detection circuit is implemented by a comparator LM 393.

In one embodiment of the invention, the pulse ignition circuit is driven by an AC220V alternating current electric connection, generates an ignition high voltage of about 12-16 kV through a high-voltage pack secondary winding and applies the ignition high voltage to an ignition electrode of the gas wall-mounted furnace, so that the ignition function is completed.

In an embodiment of the present invention, the main control board adopts rassa R5F100 DA.

In an embodiment of the present invention, the display setting board includes a R7F0C907B single chip microcomputer circuit, and a nixie tube driving circuit and a key circuit connected to the R7F0C907B single chip microcomputer circuit.

The invention also provides a control method based on the gas wall-mounted boiler control system, which is realized as follows:

(1) standby mode:

the main control board controls the relay driving circuit and the pulse ignition circuit to stop working;

(2) normal operation in heating mode:

firstly, when the temperature T of circulating water is less than or equal to a set temperature TS-a set start/stop temperature difference Delta T, a gas wall-mounted boiler control system works in a heating state; the main control board starts the water pump to run for 10 seconds through the relay drive circuit, then starts the fan through the relay drive circuit, if the water detection state is detected, the fan is started through the relay drive circuit after a water flow signal is detected, ignition is started through the pulse ignition circuit after a normal wind pressure signal is detected, and ignition is stopped after a flame signal is detected through the flame detection circuit after 0.5 second of ignition is detected;

after ignition, gradually adding small fire to large fire for combustion in a gas wall-mounted boiler control system within 2 minutes, and gradually adjusting the gas wall-mounted boiler control system to be switched to small fire for heating when the circulating water temperature T is TS-5 ℃ until the circulating water temperature T reaches a set temperature, stopping combustion and entering a heat preservation state; if the temperature is gradually reduced to T < TS-5 ℃ in the process of gradually changing to small fire heating, the temperature is gradually changed to large fire heating again, combustion is stopped after the temperature is heated to the set temperature through circulation, a water pump and a fan are continuously controlled through a relay driving circuit to clean for 30 seconds, the water pump enters a heat preservation state, and the water pump enters a circulation working state of stopping for 8 minutes and rotating for 3 minutes or a long-rotating working state in the heat preservation state;

if the temperature T of circulating water can not reach Ts within 30 minutes after the small fire is heated, the control system of the gas wall-mounted boiler stops burning, keeps the water pump delaying for 3 minutes through a relay drive circuit, cleans the fan for 30 seconds, and rotates for 3 minutes to circularly work according to the fact that the water pump stops working for 8 minutes;

(3) bathroom water mode:

detecting the water flow of the bathroom water: the main control board receives a water flow signal through the sensor interface circuit, and when the water flow is more than or equal to 3.5L/min, the bathroom function is started, and when the water flow is less than or equal to 3L/min, the bathroom function is closed;

setting the bathroom water temperature on the display setting board by a user, setting the actual temperature to be lower than the target temperature and the wind pressure signal to be normal under the condition that a bathroom water flow switch is turned on, starting ignition combustion by the main control board through the pulse ignition circuit, then entering PID (proportion integration differentiation) regulation, and keeping current output unchanged after heat load is balanced; and extinguishing the engine when the temperature T of the circulating water is more than or equal to 70 ℃ until the temperature T of the circulating water is less than or equal to Ts, and restarting the engine.

In an embodiment of the present invention, the heating mode and the bathroom water mode are switched:

1) the switching between the heating mode and the bathroom water mode can be realized by the corresponding key function of the display setting plate at any time;

2) the bathroom water mode priority function is that if a hot water valve is opened during combustion in a heating mode, a gas wall-mounted boiler control system immediately stops a water pump to be converted into a shower heating state, the firepower is adjusted according to the load, and after the temperature of bathroom water circulating water reaches a set temperature, the gas wall-mounted boiler constantly works according to the set temperature;

3) and after the bathroom water mode is finished, the fan is controlled to clean for 30S, the water pump rotates for 30S, and the gas wall-mounted boiler control system automatically enters the heating mode.

Compared with the prior art, the invention has the following beneficial effects: the automatic control of the wall-mounted gas boiler can be realized, and the stability, the anti-interference performance and the product quality of the system are improved through software control.

Drawings

Fig. 1 is a control schematic block diagram of a gas wall-hanging stove control device according to the present invention.

Fig. 2 is a schematic diagram of a switching power supply circuit of the present invention.

Fig. 3 is a schematic diagram of a relay drive circuit of the present invention.

FIG. 4 is a schematic diagram of the flame detection circuit of the present invention.

Fig. 5 is a schematic diagram of the pulse ignition circuit of the present invention.

Fig. 6 is a schematic diagram of the proportional valve drive circuit of the present invention.

Fig. 7 is a schematic diagram of a sensor interface circuit of the present invention.

Fig. 8 is a schematic diagram of the master board circuitry of the present invention.

Fig. 9 is a schematic diagram of a nixie tube driving circuit according to the present invention.

FIG. 10 is a schematic diagram of the key circuit of the present invention.

FIG. 11 is a schematic diagram of the single-chip microcomputer and EEPROM circuit of the present invention.

Fig. 12 is a main program flow chart of the main control board.

Fig. 13 is a flowchart of the antifreeze operation water pump routine.

Fig. 14 is a flowchart of a combustion control routine.

Fig. 15 is a flowchart showing the setup board main routine.

Fig. 16 is a communication mode between the main control board and the display setting board.

FIG. 17 is a block diagram of a PID parameter adaptive control system based on a genetic algorithm.

FIG. 18 is a PID parameter tuning optimization design flow of a genetic algorithm.

Detailed Description

The technical scheme of the invention is specifically explained below with reference to the accompanying drawings.

As shown in fig. 1, the invention provides a control system for a wall-mounted gas boiler, which comprises a main control board, a sensor interface circuit connected with the main control board and used for transmitting signals acquired by a sensor, a relay drive circuit used for controlling a fan, a water pump and a three-way reversing valve, a flame detection circuit used for detecting ignition flame of the wall-mounted gas boiler, a pulse ignition circuit used for realizing ignition of the wall-mounted gas boiler, a display setting board used for realizing key input and display output, a proportional valve drive circuit used for realizing automatic constant water outlet temperature of the wall-mounted gas boiler, and a switching power supply circuit used for supplying power to the whole system.

(1) standby mode:

(2) normal operation in heating mode:

(3) bathroom water mode:

The following is a specific implementation of the present invention.

The invention relates to a wall-mounted gas boiler control system, which comprises the following hardware:

1. switching power supply circuit

The main chips of the switching power supply circuit are high performance current mode PWM power switches OB233F, 7805 and MC34063 and a main transformer ef20. the control board mainly uses voltages of 24V and 5V, where the main switching power supply outputs 24V (VCC24V) and 8V,8V are converted to 5V output through the chip 7805. The 24V is mainly used for supplying power for the relay and the proportional valve. 8V is converted into 5V through the chip 7805 to be used by an ion thermal detection circuit, and the interference of a single chip microcomputer MCU is avoided. The 5V of the MCU is converted by a BUCK circuit controlled by the MC 34063. The circuit is shown in figure 2.

2. Relay drive circuit

The main control board needs low voltage to control high voltage, a relay is used for controlling 220V voltage to switch on and off to control the fan, the water pump, the three-way reversing valve and other peripherals, and because the relay is an inductive load, in order to simplify the design, the ULN2003 is a high-voltage large-current Darlington transistor array series product, has the characteristics of high current gain, high working voltage, wide temperature range, strong load carrying capacity and the like, and is suitable for various systems requiring high-speed and high-power driving. And a diode for eliminating coil back electromotive force is integrated inside, and the device is particularly suitable for relay driving. As shown in fig. 3.

The relay driving circuit connection method can ensure from hardware that S8050 is conducted only when GV-PWM pulse signals exist, meanwhile, when TSK has 24V voltage, K6 and K7 relays are closed, 220V live wire enters a system, then is input to a FAN FAN-L, and simultaneously is input to an igniter FIRE-L and an alternating current electromagnetic Valve GL-L, then is input to GV-L2 of the alternating current electromagnetic Valve, and outputs Valve + and Valve-through an alternating current shaping circuit, and a direct current switch electromagnetic Valve is controlled through a K5 relay. Through two relays of K6, K7 series connection, effectively avoided the relay inefficacy alternating current solenoid valve can't turn off the danger.

In addition, fig. 3 simultaneously realizes the function of a stop valve, namely, the gas can be ensured to be cut off under any fault condition, and the main protection measures are as follows:

(1) once the limit temperature controller is switched off, the switch valve driving voltage 24V is immediately switched off, the relay is immediately switched off, and the stop valve is closed.

(2) Two relays are connected in series on the loop, so that no danger is caused when any relay is short-circuited and fails.

(3) MCU fail safe, GV-must be the PWM signal that accords with the regulation, Q1 can switch on, starts the stop valve. The circuit principle is as follows: when GV-is high, C15 forms a loop through R41 and D7 to charge C14, Q1 is conducted, C15 cannot provide C14 charging current after charging is completed, C14 gradually discharges through R40 and Q1, the voltage of Q1 Vbe is reduced after a period of time, and Q1 is turned off. The function of D10 is to complete the draining of C15 charge for devices that are low at GV and charge up going high at GV.

(4) One way uses drive chip ULN2003, and the other way uses triode drive, prevents that certain component from becoming invalid and producing danger.

3. Flame detection circuit

The oscillation coil generates alternating voltage on the probe, and by utilizing flame one-way conductivity, as shown in fig. 4, the capacitor C28 is charged by the ion current generated after flame rectification, the comparator is triggered after the capacitor is charged to a certain voltage, and the comparator LM393 outputs low level. In the absence of flame, the winding is open, C28 has no charging current, and comparator LM393 outputs a high level. When the probe is short-circuited to ground (or leaks), the voltage of C28 cannot be charged to the reversed level because the ac impedance of the capacitor is 0, and the comparator outputs a high level.

4. Pulse ignition circuit

As shown in fig. 5, the ignition circuit is driven by an AC220V AC electrical power connection, where D28 is a self-triggering thyristor (high voltage trigger tube) and the discharge voltage is 150V. When the voltage at the two ends of the energy storage circuit C12 reaches 150V, the D28 is automatically conducted, the electric energy in the C12 is released through the D28 and the primary winding of the high-voltage pack T2, an ignition high voltage of about 12-16 kV is generated at the secondary side of the T2, and the ignition voltage is added on an ignition electrode of a water heater of the gas wall-hanging stove to generate ignition sparks, so that the function of ignition is completed.

5. Proportional valve drive circuit

As shown in fig. 6, the driving circuit of the gas proportional valve is controlled by a single chip, and the average current of the proportional valve is controlled by outputting a PWM wave, that is, the opening of the proportional valve is controlled, so as to adjust the fire power of the gas wall-hung boiler water heater in a stepless manner, thereby achieving the automatic constancy of the outlet water temperature of the gas wall-hung boiler water heater. R79 and C39, C40 produce the integral circuit (similar to the slope generator), the circuit of U12A is formed as the first-order follower circuit, U12B controls Q4S 8050 switching state through R90 (collecting current) and slope comparison, Q4S 8050 drives the switch of the power amplifier TIP 42C. The control of the current of the proportional valve is realized (the inductance of the proportional valve is about 180mH, and the internal resistance is 80 omega).

6. Sensor interface circuit

As shown in fig. 7, because the wall-mounted furnace has a severe working environment, a diode needs to be added at an input port for protection, and a filter capacitor and a series resistor need to be added to protect an MCU IO port. The sensor interface mainly comprises an overheating protection interface, a bathroom heating temperature interface, a water pressure detection interface, a water flow sensor interface, a wind pressure switch interface and a room temperature detection interface.

7. Main control board

As shown in fig. 8, the main control board uses rassa R5F100DA (16-bit controller, 48kB flash memory), and combines the advanced functions of 78K and R8C series, which can realize low power consumption (66uA/MHz) and high performance (41DMIPS @32 MHz).

RL78 is based on a 16-bit CISC architecture with rich emulation capabilities. Wide application and general purpose devices, LCD and ASSP, lighting and automotive microcontrollers. RL78 is designed specifically for ultra-low power applications, enabling customers to build compact and energy efficient systems at low cost, with high precision (+ -1%) chip oscillators facilitating 32MHz CPU operation, without external crystal oscillators, with built-in optional power-on reset and watchdog timer functions

8. Display setting board

The display setting board consists of a nixie tube driving circuit, a key circuit, a singlechip and an EEPROM;

nixie tube driving circuit

As shown in fig. 9, since the display content is small and the driving power is small, the nixie tube is directly driven through the port of the single chip microcomputer. The nixie tube scanning is realized by controlling the switches of the triode 8050Q1 and the Q2, the current of the nixie tube is limited by connecting the 1K omega resistor in series, and the MCU and the nixie tube are protected.

Key circuit

As shown in fig. 10, the key is directly driven by external interrupt, capacitance filtering and port protection resistance are added, and the passive buzzer is driven by PNP. The main keys comprise 5 keys for season selection, temperature +, temperature-, switching, resetting and the like, and control and display of the wall-hanging furnace system are completed

Singlechip and EEPROM

As shown in fig. 11, the R7F0C907B and R7F0C90X series microcontrollers of rassa selected by the single chip microcomputer adopt an RL78 kernel, and on the products, high-speed processing performance and lowest power consumption are realized at the same time, and the single chip microcomputer has a series of wide product array capacity with low pin count, and is suitable for consumer product application. The high-precision +/-1% on-chip oscillator (TA-20- +85 ℃) enables the running of a CPU to reach 24MHz, meanwhile, functions of optional power-on reset, watchdog timers and the like are built in, and the series of products have 32-pin LQFP packages (with the space of 0.8 mm) and are suitable for household appliances and common consumers. As the wall-mounted furnace requires to store the set parameters and the alarm information, the storage of the system parameters is completed by externally connecting a 2K EEPROM 24C02 chip to I2C.

Secondly, the main control board software design of the gas wall-hanging stove control system of the invention:

the main control board controller software needs to enable the heating hot water function of the gas wall-mounted boiler to normally operate, and main basic functions which need to be realized include heating of domestic water, heating of heating circulating water, freezing prevention, circulation pump blocking prevention and the like. The software design of the main control board single chip microcomputer adopts a real-time multitask system, and the main program mainly realizes the control function of the single chip microcomputer on the gas heating water heater.

1. Main program flow chart and working mode design

The main flow chart of the software system is shown in fig. 12, and the software system is divided into the following modes:

(1) standby mode

In standby mode, all outputs are stopped. Stop receiving all heating requests except for the anti-freeze function. If the fan and the water pump are running, the circulation is finished and then the operation is stopped.

(2) Normal operation mode in heating mode

The temperature of the heating water arranged on the control panel. If the temperature of the heating water is lower than the heating starting temperature of the heating water, the indoor temperature controller is closed, and the operation panel is started without timing or with timing, and the three conditions are met simultaneously, the automatic combustion control part starts the machine according to the starting step. The specific working steps are as follows:

if the system is set in the heating mode, the system works in the heating state when the circulating water temperature T is less than or equal to TS (set temperature) and delta T (set start-stop temperature difference). Starting the fan after the water pump is started to operate for 10 seconds, (if the water flow switch is in a water detection state, starting the fan after the water flow switch is detected to be closed), starting ignition after the wind pressure switch is detected to be normal, starting the electromagnetic valve after the ignition is carried out for 0.5 second, and stopping the ignition after the flame signal is detected.

And secondly, after the fire is ignited, gradually adding the small fire to the large fire for burning within 2 minutes, gradually adjusting the system to be switched to the small fire for heating when the water outlet temperature T is TS (set temperature) -5 ℃, and stopping burning and entering a heat preservation state until the water outlet temperature reaches the set temperature. And in the process of gradually changing to small fire heating, if the temperature is gradually reduced to T less than TS-5 ℃, slowly changing to large fire heating. Thus circulating. Heating to set temperature, stopping combustion, cleaning with water pump and blower for 30S, keeping warm, and circulating for 3 min after water pump stops rotating for 8 min (or water pump rotates for a long time)

Thirdly, if the outlet water temperature T can not reach the set temperature Ts within 30 minutes after the small fire is heated, the system stops burning, keeps the water pump delaying for 3 minutes, cleans the fan for 30 seconds, and rotates for 3 minutes according to 8 minutes of stopping of the water pump for circulating work.

(3) Bathroom water mode

Bathroom water flow detection

And detecting a pulse type water flow sensor, starting the bathroom function when the water flow is more than or equal to 3.5L/min, and closing the bathroom function when the water flow is less than or equal to 3L/min.

Second, normal working mode

The user panel is provided with bathroom water temperature, under the condition that a bathroom water flow switch is turned on, the actual temperature is lower than the target temperature, a wind pressure switch is normal, PID adjustment is carried out after the ignition combustion is started, and the current output is unchanged after the heat load is balanced. When the water outlet temperature T is more than or equal to 70 ℃, the machine is flamed out, and the machine is restarted until the water outlet temperature T is less than or equal to Ts ℃. The bathroom water flow switch is turned off and the boiler is turned off.

Hot water function conversion for heating/shower

1) The heating/shower function can be switched by a panel 'winter/summer' button at any time.

2) The shower priority function is that if a hot water valve is opened during heating combustion, the system immediately stops the water pump to be switched to a shower heating state, the system adjusts the firepower according to the load, and after the shower outlet water temperature reaches the set temperature, the system works constantly according to the set temperature.

3) After the shower is finished (the shower water valve is closed), the fan is required to clean for 30S, the water pump is rotated for 30S, and the system automatically enters the original heating state.

2. Working mode design of water pump

(1) Water pump working mode in heating mode

In the heating state, the water pump is operated all the time. And when the heating is stopped to the set temperature, the water pump stops for 8 minutes according to 3 minutes of rotation and operates circularly or continuously. When a shutdown request exists when the water pump is in operation or a fault is detected, the water pump and the fan are operated for 30S and are closed.

(2) Fault operation water pump

When the overheating protection fault of the mechanical temperature controller occurs and the system is in heating priority, the water pump and the fan are operated for 30S and closed.

(3) Anti-sticking function operation water pump

If the time from the last water pump operation is more than 21 hours, the water pump will operate for 30 seconds. The heating device plays a role in heating and bathroom modes.

(4) Anti-freezing running water pump

And after the system enters the first-stage anti-freezing state, starting a water pump to operate, and when the temperature reaches the anti-freezing stop temperature, circulating the water pump for 3 minutes. And after the system enters the secondary anti-freezing state, starting a water pump to operate, and circulating the water pump for 30 minutes after the temperature reaches the anti-freezing stop temperature. The flow chart is shown in fig. 13.

3. Design of working mode of proportional valve

During each ignition, the proportional valve outputs ignition current slowly to prevent the proportional valve from being adhered or not igniting. The output is proportionally regulated during combustion. In the heating mode, after the flame is detected within the safe time, the combustion is slowly superimposed with a slope within TfS (first-stage combustion adjustment time) time 120 seconds. When the heating temperature reaches Ts-5 ℃, the proportional valve is adjusted to the minimum opening degree for combustion.

4. Combustion control program design (FIG. 14 is the main flow chart of the combustion control program)

The starting process comprises the following steps: in the starting process, the boiler detects flame, wind pressure, water pressure and overheating protection signals. If no fault exists, the igniter is opened, the gas valve is opened, and the proportional valve outputs the set ignition current.

And (3) combustion state: and after the flame is detected, the output of the proportional valve is adjusted according to the actual/set temperature. The gas valve is closed when no flame, no water flow signal or fault is detected.

And (4) ending combustion: after heating combustion is stopped, the fan keeps cleaning for 30 seconds and then stops, and the water pump operates according to a water pump working mode. After the shower combustion is stopped, the blower and the water pump are kept for cleaning for 30 seconds and then the shower combustion is stopped.

Third, the invention gas hanging stove control system display set board software design

The display setting board mainly completes the state display and the system control of the current gas wall-mounted boiler system, and the main keys and the corresponding functions comprise the following 5 keys:

on/off key: when the system is electrified, the system can be switched between a default heating mode and a power-off state by pressing a switch key. The setting parameter setting is performed by a confirmation key.

The 'winter and summer' key: when the furnace is in a normal starting state, the seasonal mode can be switched by pressing a 'winter and summer' key; "summer" represents a summer bathroom function (the green lamp in the winter/summer mode is long and bright under the condition of water flow, and the green lamp in the winter/summer mode is flashing under the condition of no water flow), and "winter" represents a winter heating function (the yellow lamp in the winter/summer mode is long and bright under the normal operation state of the machine, and the yellow lamp in the winter/summer mode is flashing under the stop operation state or the heat preservation state of the machine). Under the heating mode, shower water is turned on, and the yellow light and the green light of the indicator light flash alternately.

The "reset" key: 1. when the system is in a fault state, the reset key is pressed once, and the state before the fault can be restored and restarted. 2. In the power-on no-fault state, a long-time press of the reset key 10s enters system parameter setting.

Key "up" key: the set operating temperature or system parameters are adjusted upward.

The "down-regulation" bond: the operating temperature or system parameters are set and adjusted downward.

The temperature is adjusted by pressing the up-down key, adjusting the temperature and then pressing the confirm key. Under the condition of setting temperature or system parameters, data is not changed, data is not sent, only query is carried out, and exit is carried out by pressing a confirmation key. The main program flow of the setup board is shown in FIG. 15.

Communication protocol design between main control board and display setting board

The serial port communication mode between the wall-hanging stove setting board and the main control board is shown in fig. 16, wherein the packet data does not exceed 256 bytes, the data packet is verified and analyzed correctly after the receiving is finished, the response is carried out, and the data packet is immediately disconnected after the sending is finished. When the data transmission fails, the data is retransmitted for three times, and when the data is retransmitted for the third time, the main control board end should give a response, and wait for receiving the next group of data as automatically giving up the current group of data (the setting board is sent by key operation without a repeating mechanism, and the main control board has a repeating mechanism). The command packet format is shown in table 1 and the command encoding is shown in table 2.

TABLE 1

TABLE 2

Fifthly, temperature control algorithm design of the invention

The wall-mounted gas boiler is a household appliance for both heating and supplying domestic hot water, and under the condition of a certain structure of the whole boiler and a certain heat value of gas, the temperature of the outlet water is directly determined by the temperature of the inlet water, the gas quantity and the water flow controlled by a proportional valve. Because the gas wall-mounted boiler is a complex control object, the original PID control has no obvious advantages in overshoot, regulation time, steady-state error and anti-interference performance, and the whole system cannot establish an accurate mathematical model, the traditional PID controller design has the difficulty of parameter setting, mainly through manual experience debugging, the method has the defects of poor subjectivity, poor portability and the like, and is difficult to meet the actual control requirement, and the genetic algorithm shows the characteristic of parallelism in group evolution, so the method can search in different local ranges, 3 parameters of the PID are coded into a chromosome form of the genetic algorithm through the intelligent genetic algorithm, the online self-adaptive optimization of the PID parameters is realized through genetic operation, the PID parameters can change along with the change of the controlled object, and the optimal solution of the PID parameters is realized. The algorithm design realizes intelligent adjustment and control of the traditional gas wall-mounted boiler, so that the stability, the anti-interference performance and the product quality of the system are improved. A block diagram of the adaptive control system based on the genetic algorithm PID parameters is shown in fig. 17.

The flow of the PID parameter tuning optimization design of the genetic algorithm is shown in FIG. 18. And (3) encoding of parameters: in the PID controller, three parameters of proportional coefficient Kp, integral time Ki and differential time Kd need to be coded, and a binary Gray coding mode with strong searching capability is selected to carry out joint coding on PID control parameters.

Fitness function: the expression of the fitness function selected by the system is shown as follows

Wherein e (t) is the system error, u (t) is the temperature control quantity, t_uIs the rise time, w₁、w₂、w₃Is the weight value of the weight value,

selecting operation: adopting the elite retention strategy of the championship game in the earlier stage, rejecting the vulnerable individuals, adopting a non-linear selection mode based on roulette in the later stage, increasing the population diversity and accelerating the evolution speed, wherein the corresponding individual selection expression is as follows:

wherein M is population university, F_KIs the Kth chromosome fitness function value, P_KIs the probability that the Kth chromosome is selected to a new population

And (3) cross operation: compared with a single-point crossing mode, the uniform crossing mode can process each binary system, the mode enables genetic algorithm searching to be enlarged in a parameter space range, and therefore global searching capacity and algorithm optimization efficiency are improved.

Mutation operation: a uniform inversion method is to be used, i.e. a part of components of a parent vector is selected according to probability and then inverted.

Algorithm parameters: group Size 50, crossover ratio P_C0.5, initial value of mutation probability P_m0.05 and changes with the fitness function, and the maximum evolution algebra is 100.

The above are preferred embodiments of the present invention, and all changes made according to the technical scheme of the present invention that produce functional effects do not exceed the scope of the technical scheme of the present invention belong to the protection scope of the present invention.

Claims

1. The utility model provides a gas hanging stove control system, a serial communication port, including the main control board and be connected with this main control board be used for transmitting the sensor acquisition signal's sensor interface circuit, a relay drive circuit for controlling the fan, a water pump, the tee bend switching-over valve, a flame detection circuitry for detecting gas hanging stove ignition flame, a pulse ignition circuit for realizing gas hanging stove ignition, a display setting board for realizing key input, show output, a proportional valve drive circuit for realizing gas hanging stove goes out the automatic constancy of water temperature, and be used for the switching power supply circuit for entire system power supply.

2. The gas wall-hanging stove control system according to claim 1, wherein the sensor interface circuit comprises a wind pressure switch detection interface circuit, a water pressure switch detection interface circuit, an overheat protection interface circuit, a water flow sensor interface circuit, a bathroom/heating temperature detection interface circuit, and a room temperature detection interface circuit.

3. The gas wall-hanging stove control system according to claim 1, wherein the relay drive circuit comprises a fan output control circuit, a water pump output control circuit, a three-way reversing valve output control circuit, and a solenoid valve output control circuit.

4. The gas wall hanging stove control system according to claim 1, wherein the relay driving circuit employs ULN 2003.

5. The gas wall-hanging stove control system according to claim 1, characterized in that the flame detection circuit is implemented with a comparator LM 393.

6. The gas wall-hanging stove control system according to claim 1, wherein the pulse ignition circuit is driven by an AC220V alternating current electric connection, generates an ignition high voltage of about 12-16 kV through a high voltage package secondary winding and applies the ignition high voltage to an ignition electrode of the gas wall-hanging stove to achieve an ignition function.

7. The gas wall-hanging stove control system according to claim 1, characterized in that the main control board adopts pizza R5F100 DA.

8. The gas wall-hanging stove control system according to claim 1, wherein the display setting board includes an R7F0C907B single chip microcomputer circuit, a nixie tube driving circuit connected with the R7F0C907B single chip microcomputer circuit, and a key circuit.

9. A control method of a gas wall-hanging stove control system based on any one of claims 1-8 is characterized by comprising the following steps:

(1) standby mode:

(2) normal operation in heating mode:

(3) bathroom water mode:

10. The control method of the gas wall-hanging stove control system according to claim 9, characterized in that the heating mode and the bathroom water mode are switched: