CN116800195A - Photovoltaic power generation and water heating control system and control method - Google Patents

Abstract

The invention relates to the technical field of photovoltaic power generation, and discloses a photovoltaic power generation heating water control system and a control method, wherein the photovoltaic power generation heating water control system comprises a main control module, a photovoltaic power generation plate cooling device, a thermoelectric power generation device and at least one thermocouple sensor; the photovoltaic power generation plate cooling device is connected with the photovoltaic power generation plate; the temperature difference power generation device is connected with the main control module; the thermocouple sensor is arranged on the photovoltaic power generation plate and connected with the main control module; the photovoltaic power generation plate cooling device comprises a photovoltaic cooling water temperature monitoring device and a photovoltaic cooling water control device; the thermoelectric generation device comprises a thermoelectric generation control device module, a thermoelectric generation sheet and a thermoelectric cooling water monitoring and controlling device; the invention solves the problem of low power generation efficiency caused by overhigh local temperature of the photovoltaic power generation plate in the prior art, and has the characteristic of ensuring the state of maximum power generation efficiency.

Description

Photovoltaic power generation and water heating control system and control method

Technical Field

The invention relates to the technical field of photovoltaic power generation, in particular to a photovoltaic power generation heating water control system and a control method.

Background

The device mainly aims at the maximum power generation efficiency and the heating water efficiency of the solar photovoltaic power generation panel, and the maximum power generation efficiency of the thermoelectric power generation, monitors the temperature of the solar photovoltaic power generation panel and the temperature difference power generation control device for controlling the temperature difference power generation device in real time, and simultaneously provides the generated hot water for a user as heating and living hot water so as to achieve the effects of energy conservation and emission reduction.

The efficiency of the solar photovoltaic power generation plate is reduced by 12.7% at 55 ℃ compared with the efficiency at 30 ℃, the efficiency of the solar photovoltaic power generation plate is reduced by 21.6% at 75 ℃ compared with the efficiency at 30 ℃, and the efficiency of the monocrystalline silicon solar photovoltaic power generation plate is about 14% at 30 ℃. The efficiency will drop by 3.0% when the temperature reaches 75 ℃. When the solar photovoltaic power generation plate is irradiated by sunlight, the photovoltaic power generation plate can generate heat, and when the local temperature of the photovoltaic power generation plate is too high, hot spots can be generated, so that the power generation efficiency is influenced, and the service life of the photovoltaic module is also influenced.

The prior art has a system for acquiring hot water by combining solar heat collection with photovoltaic power generation auxiliary air source heat pump, which comprises a solar heat collection device, a solar power generation device, a first controller, a water tank, a heat exchange tube and a first temperature sensor; the solar power generation device comprises a solar photovoltaic power generation plate, a power supply control mechanism and a main control module; the solar heat collection device heats water in the water tank by the collected heat energy converted from the first light energy; the solar photovoltaic power generation plate converts the collected 2 nd light energy into electric energy and sends the electric energy to the storage battery; the first controller sends a heating instruction generated according to the temperature value acquired by the first temperature sensor to the power supply control mechanism, and sends a first starting instruction to the main control module; the power supply control mechanism converts the storage battery into a power supply of the main control module, so that the main control module heats the heat exchange tube.

However, the problem of low power generation efficiency caused by overhigh local temperature of the photovoltaic power generation plate still exists in the prior art, so how to invent a novel photovoltaic power generation and water heating system and a control system thereof is a technical problem which needs to be solved in the technical field.

Disclosure of Invention

The invention provides a photovoltaic power generation and water heating control system, which aims to solve the problem of low power generation efficiency caused by overhigh local temperature of a photovoltaic power generation plate in the prior art and has the characteristic of ensuring the state of maximum power generation efficiency.

In order to achieve the above purpose of the present invention, the following technical scheme is adopted:

a photovoltaic power generation and heating water control system comprises a main control module, a photovoltaic power generation plate cooling device, a thermoelectric power generation device and at least one thermocouple sensor for monitoring the local temperature of the photovoltaic power generation plate;

the photovoltaic power generation plate cooling device is connected with the photovoltaic power generation plate; the temperature difference power generation device is connected with the main control module and supplies power to the main control module; the thermocouple sensor is arranged on the photovoltaic power generation plate and connected with the main control module;

the photovoltaic power generation plate cooling device comprises a photovoltaic cooling water temperature monitoring device for monitoring the temperature of the cooling water of the photovoltaic power generation plate and a photovoltaic cooling water control device for controlling the water inlet and outlet circulation of the cooling water of the photovoltaic power generation plate; the main control module is contacted with the output of the photovoltaic cooling water temperature monitoring device; the main control module is contacted with the input of the photovoltaic cooling water control device;

The thermoelectric generation device comprises a thermoelectric generation sheet for realizing thermoelectric generation through the temperature difference between cooling water and the environment, a thermoelectric generation sheet temperature monitoring device for monitoring the temperature difference of the thermoelectric generation sheet, and a thermoelectric cooling water control device for controlling the circulation of thermoelectric cooling water; the heat absorption surface of the thermoelectric generation sheet is connected with the photovoltaic power generation plate, and the heat dissipation surface of the thermoelectric generation sheet is cooled by temperature difference cooling water; the main control module is contacted with the output of the temperature monitoring device of the thermoelectric generation sheet; the main control module is contacted with the input of the temperature difference cooling water control device.

Preferably, the system further comprises a storage battery, a photovoltaic controller for inputting electricity output by the photovoltaic power generation plate into the storage battery and converting the electricity output by the storage battery into a power supply of the main control module, and a power supply control module for converting the electricity output by the thermoelectric power generation device into the power supply of the main control module and the storage battery;

the photovoltaic controller, the power supply control module and the storage battery are all connected with the main control module; the thermoelectric generation device is also connected with a storage battery to supply power to the storage battery; the photovoltaic power generation plate is connected with the storage battery; the storage battery is connected with the main control module; the photovoltaic power generation panel supplies power to the main control module through the storage battery.

Further, a cloud platform management system and an Internet of things communication module are also arranged; the communication module of the Internet of things is respectively connected with the cloud platform control system and the master control module through communication signals; the main control module uploads the received temperature information to the cloud platform management system in real time; the user can send a control instruction to the main control module through the cloud platform.

Furthermore, the photovoltaic cooling water temperature monitoring device is a photovoltaic panel circulating water temperature detection sensor; the photovoltaic cooling water control device comprises a photovoltaic power generation plate cooling water pump, a photovoltaic power generation plate cooling water inlet valve and a photovoltaic power generation plate cooling water outlet valve; the temperature of the cooling water of the photovoltaic power generation plate is monitored by a temperature detection sensor of the circulating water of the photovoltaic power generation plate and is input into a main control module; the photovoltaic power generation plate cooling water pump, the photovoltaic power generation plate cooling water inlet valve and the photovoltaic power generation plate cooling water outlet valve receive control signals from the main control module and control the inlet and outlet of the photovoltaic power generation plate cooling water.

Furthermore, the temperature monitoring device of the thermoelectric generation sheet is a temperature sensor of a radiating surface and a heat absorbing surface of the thermoelectric generation sheet; the temperature difference cooling water control device comprises temperature difference cooling water, a temperature difference cooling water pump, a temperature difference cooling water inlet valve and a temperature difference cooling water outlet valve; the temperature sensors of the radiating surface and the heat absorbing surface of the thermoelectric generation sheet monitor the temperature difference of the thermoelectric generation sheet and input the temperature difference into the main control module; the control temperature difference cooling water pump, the temperature difference cooling water inlet valve and the temperature difference cooling water outlet valve receive control signals from the main control module and control the inlet and outlet of the temperature difference cooling water.

Further, the main control module further comprises a 6-way water valve and a power output interface; the 6-way electromagnetic valve and the power output interface are respectively connected with the photovoltaic power generation plate cooling water pump, the photovoltaic power generation plate cooling water inlet valve, the photovoltaic power generation plate cooling water outlet valve, the temperature difference cooling water pump, the temperature difference cooling water inlet valve and the temperature difference cooling water outlet valve in a one-to-one correspondence manner; the main control module can directly control the photovoltaic power generation plate cooling water pump, the photovoltaic power generation plate cooling water inlet valve, the photovoltaic power generation plate cooling water outlet valve, the temperature difference cooling water pump, the temperature difference cooling water inlet valve and the temperature difference cooling water outlet valve through the 6-way electromagnetic valve and the power output interface.

Further, the device also comprises a photovoltaic power generation plate cooling control device and a thermoelectric power generation control device; the photovoltaic power generation plate cooling control device is used for receiving the temperature signal from the photovoltaic cooling water temperature monitoring device, sending the temperature signal to the main control module, receiving the control signal from the main control module and controlling the photovoltaic cooling water control device to execute; the photovoltaic power generation plate cooling control device is used for receiving the temperature signal from the temperature monitoring device of the thermoelectric power generation sheet, sending the temperature signal to the main control module, receiving the control signal from the main control module and controlling the thermoelectric cooling water control device to execute; the master control module comprises an RS485 communication interface; the main control module is connected with the cooling water control device and the thermoelectric generation control device of the photovoltaic power generation panel through the RS485 communication interface respectively.

Further, the main control module comprises an asynchronous serial communication data output port and an asynchronous serial communication data input port; the communication circuit of the RS485 communication interface comprises a MAX485 master control chip, a triode Q1, resistors R1, R4 and R7 and an optical coupler; the pins b, c and e of the triode Q1 are respectively and sequentially electrically connected with an asynchronous serial communication data output port, RE# and DE pins DI; the asynchronous serial communication data input port is electrically connected with an R0 pin of the MAX485 master control chip; one end of the resistor R1 is grounded, and the other end of the resistor R1 is respectively and electrically connected with the pin B of the MAX485 master control chip, one end of the resistor R4 and the pin 1 of the optocoupler; the other end of the resistor R4 is respectively and electrically connected with the pin A of the MAX485 master control chip, one end of the resistor R7 and the pin 2 of the optocoupler; the other end of the resistor R7 is electrically connected with a +5V power supply;

during the data transmission process:

when the asynchronous serial communication data output port is 0, the triode Q1 is not conducted, the MAX485 communication chip RE# and DE are high level, the MAX485 communication chip enters a transmission mode, and at the moment, the MAX485 communication chip transmits the low level of the DI pin of the MAX485 communication chip outwards through the A, B pin of the MAX485 communication chip;

when the asynchronous serial communication data output port is 1, the triode Q1 is conducted, RE# and DE of the MAX485 communication chip are high level, a pin A, B of the MAX485 communication chip enters a high-resistance state, at the moment, the level of the pin A is pulled up by the resistor R7, the level of the pin B is pulled down by the resistor R1, and at the moment, the MAX485 communication chip sends data 1 to the outside through the pin A, B;

In the course of the data reception process,

the asynchronous serial communication data output port always keeps a high level '1', the asynchronous serial communication data input port is in a data input state, the triode Q1 is conducted, pins RE# and DE of the MAX485 communication chip are in a high-level MAX485 communication chip A, B and enter a data high-resistance state, and at the moment, when the level of an A pin is more than the level of a B pin and the level of a phase difference is 0.2V, the RO pin outputs a high level; when the level of the pin A is less than the level of the pin B by 0.2V, the pin RO outputs a high level; the RO pin outputs high level change, and the data 1 and 0 are transmitted to the main control module through the asynchronous serial communication data input port.

A control method based on the photovoltaic power generation and water heating control system of claim 1, comprising the following specific steps:

s1, supplying power to a main control module through a photovoltaic power generation plate and a thermoelectric power generation device; monitoring the cooling water temperature of the photovoltaic power generation plate through a photovoltaic cooling water temperature monitoring device; monitoring the temperature difference of the thermoelectric generation sheet through a temperature monitoring device of the thermoelectric generation sheet; monitoring the local temperature of the photovoltaic power generation plate through a thermocouple sensor; the temperature of the thermoelectric generation sheet, the temperature information of cooling water of the photovoltaic generation plate and the local temperature information of the photovoltaic generation plate are received in real time through the main control module;

S2, if the local temperature of the cooling water or the photovoltaic power generation plate is judged to be too high, a signal is sent to a photovoltaic power generation plate cooling device through a main control module, water inlet and outlet circulation of the photovoltaic power generation plate cooling water is controlled through a photovoltaic cooling water control device, the temperature of the photovoltaic power generation plate cooling water is reduced, and the photovoltaic power generation plate is cooled; if the temperature difference of the temperature difference power generation piece is insufficient, a signal is sent to the temperature difference power generation device through the main control module, and the water inlet and outlet circulation of the temperature difference cooling water is controlled through the temperature difference cooling water control device.

Preferably, the main control module further comprises a 6-way water valve and a power output interface; the main control module further comprises a plurality of electromagnetic valves and a power output interface; the electromagnetic valves and the power output interfaces are respectively and correspondingly connected with the photovoltaic cooling water temperature and monitoring control device and the photovoltaic cooling water control device and the temperature difference cooling water control device;

in the step S2, the photovoltaic cooling water control device and the temperature difference cooling water control device can be directly controlled through a plurality of paths of electromagnetic valves and power output interfaces directly through the main control module.

The beneficial effects of the invention are as follows:

the invention discloses a photovoltaic power generation and water heating control system which comprises a main control module, a photovoltaic power generation plate cooling device, a thermoelectric power generation device and at least one thermocouple sensor for monitoring the local temperature of the photovoltaic power generation plate. Aiming at the problems that the local temperature of the photovoltaic power generation plate is too high, hot spots are generated, the power generation efficiency is affected, and the service life of a photovoltaic module is prolonged, the invention monitors the temperature of cooling water of the photovoltaic power generation plate, and controls the cooling water of the photovoltaic power generation plate to circulate in and out of water. The invention also monitors the temperature difference of the temperature difference power generation piece and controls the circulation of temperature difference cooling water, thereby realizing efficient temperature difference power generation; therefore, the method solves the problem of low power generation efficiency caused by overhigh local temperature of the photovoltaic power generation plate in the prior art, and has the characteristic of ensuring the state of maximum power generation efficiency.

Drawings

FIG. 1 is a schematic diagram of a photovoltaic power generation and water heating system according to the present invention

Fig. 2 is a functional block diagram of a photovoltaic power generation and water heating control system according to the present invention.

FIG. 3 is a schematic diagram of a specific hardware design of a photovoltaic power generation and water heating control system according to the present invention.

Fig. 4 is a schematic diagram of a +5v voltage stabilizing circuit of a power module of a main control module of a photovoltaic power generation and water heating control system.

Fig. 5 is a schematic diagram of a +12v voltage stabilizing circuit of a power module of a main control module of a photovoltaic power generation and water heating control system.

Fig. 6 is a schematic diagram of an RS485 communication circuit of a master control module of a photovoltaic power generation and water heating control system according to the present invention.

Fig. 7 is a schematic diagram of a control circuit of a water pump and a solenoid valve of a main control module of a photovoltaic power generation and water heating control system.

Fig. 8 is a schematic diagram of a thermocouple interface circuit of a main control module of a photovoltaic power generation and water heating control system according to the present invention.

Fig. 9 is a schematic diagram of a control flow of a photovoltaic power generation and water heating control system according to the present invention.

Fig. 10 is a schematic diagram of a flow chart of a MODBUS protocol query response data of RS485 communication of a photovoltaic power generation and water heating control system.

FIG. 11 is a schematic diagram of a thermocouple voltage acquisition and conversion process of a photovoltaic power generation and water heating control system according to the present invention.

FIG. 12 is a schematic diagram of the installation positions of a single solar photovoltaic panel temperature measuring point and a water valve of the photovoltaic power generation and water heating control system.

Fig. 13 is a schematic flow chart of a control method for generating hot water by photovoltaic power generation according to the invention.

Detailed Description

The invention is described in detail below with reference to the drawings and the detailed description.

Example 1

As shown in fig. 1, the photovoltaic power generation and water heating control system comprises a main control module, a photovoltaic power generation plate cooling device, a thermoelectric power generation device and at least one thermocouple sensor for monitoring the local temperature of the photovoltaic power generation plate;

the photovoltaic power generation plate cooling device is connected with the photovoltaic power generation plate; the temperature difference power generation device is connected with the main control module and supplies power to the main control module; the thermocouple sensor is arranged on the photovoltaic power generation plate and connected with the main control module;

the photovoltaic power generation plate cooling device comprises a photovoltaic cooling water temperature monitoring device for monitoring the temperature of the cooling water of the photovoltaic power generation plate and a photovoltaic cooling water control device for controlling the water inlet and outlet circulation of the cooling water of the photovoltaic power generation plate; the main control module is contacted with the output of the photovoltaic cooling water temperature monitoring device; the main control module is contacted with the input of the photovoltaic cooling water control device;

The thermoelectric generation device comprises a thermoelectric generation sheet for realizing thermoelectric generation through the temperature difference between cooling water and the environment, a thermoelectric generation sheet temperature monitoring device for monitoring the temperature difference of the thermoelectric generation sheet, and a thermoelectric cooling water control device for controlling the circulation of thermoelectric cooling water; the heat absorption surface of the thermoelectric generation sheet is connected with the photovoltaic power generation plate, and the heat dissipation surface of the thermoelectric generation sheet is cooled by temperature difference cooling water; the main control module is contacted with the output of the temperature monitoring device of the thermoelectric generation sheet; the main control module is contacted with the input of the temperature difference cooling water control device.

In a specific embodiment, the system further comprises a storage battery, a photovoltaic controller for inputting electricity output by the photovoltaic power generation plate into the storage battery and converting the electricity output by the storage battery into a power supply of the main control module, and a power supply control module for converting the electricity output by the thermoelectric power generation device into the power supply of the main control module and the storage battery;

the photovoltaic controller, the power supply control module and the storage battery are all connected with the main control module; the thermoelectric generation device is also connected with a storage battery to supply power to the storage battery; the photovoltaic power generation plate is connected with the storage battery; the storage battery is connected with the main control module; the photovoltaic power generation panel supplies power to the main control module through the storage battery.

In this embodiment, the cooling water is heated and heated during the cooling process of the solar photovoltaic power generation panel, and the heated cooling water can be used for providing shower, cleaning and other purposes for other users.

In the embodiment, the thermoelectric generation sheet generates electricity through the temperature difference between the heat radiating surface and the heat absorbing surface of the semiconductor generation sheet, and when the temperature difference is 20 ℃, the open circuit voltage is 0.97V, and the current is 225mA; when the temperature difference is 40 ℃, the open circuit voltage is 1.8V, and the current is 368mA; the open circuit voltage was 3.6V and the current was 469mA when the temperature difference was 60 ℃; when the temperature difference is 80 ℃, the open-circuit voltage is 3.6V, and the current is 558mA; the heat-conducting paste is added to the heat-absorbing surface of the semiconductor power generation sheet to be attached to the back surface of the solar photovoltaic power generation sheet, so that the heat dissipation of the solar photovoltaic power generation sheet is realized, the heat-absorbing surface of the semiconductor power generation sheet is heated to be heated, tap water or air-conditioning cooling water enters the heat-absorbing surface of the semiconductor power generation sheet as temperature difference cooling water to dissipate heat, the temperature difference between the heat-absorbing surface and the heat-absorbing surface of the semiconductor power generation sheet is increased, and the power generation capacity of the semiconductor power generation sheet is improved.

Example 2

More specifically, as shown in fig. 2, a photovoltaic power generation and water heating control system comprises a main control module, a photovoltaic power generation plate cooling device, a thermoelectric power generation device and at least one thermocouple sensor for monitoring the local temperature of the photovoltaic power generation plate;

The photovoltaic power generation plate cooling device is connected with the photovoltaic power generation plate; the temperature difference power generation device is connected with the main control module and supplies power to the main control module; the thermocouple sensor is arranged on the photovoltaic power generation plate and connected with the main control module;

the photovoltaic power generation plate cooling device comprises a photovoltaic cooling water temperature monitoring device for monitoring the temperature of the cooling water of the photovoltaic power generation plate and a photovoltaic cooling water control device for controlling the water inlet and outlet circulation of the cooling water of the photovoltaic power generation plate; the main control module is contacted with the output of the photovoltaic cooling water temperature monitoring device; the main control module is contacted with the input of the photovoltaic cooling water control device;

the thermoelectric generation device comprises a thermoelectric generation sheet for realizing thermoelectric generation through the temperature difference between cooling water and the environment, a thermoelectric generation sheet temperature monitoring device for monitoring the temperature difference of the thermoelectric generation sheet, and a thermoelectric cooling water control device for controlling the circulation of thermoelectric cooling water; the heat absorption surface of the thermoelectric generation sheet is connected with the photovoltaic power generation plate, and the heat dissipation surface of the thermoelectric generation sheet is cooled by temperature difference cooling water; the main control module is contacted with the output of the temperature monitoring device of the thermoelectric generation sheet; the main control module is contacted with the input of the temperature difference cooling water control device.

In a specific embodiment, the system further comprises a storage battery, a photovoltaic controller for inputting electricity output by the photovoltaic power generation plate into the storage battery and converting the electricity output by the storage battery into a power supply of the main control module, and a power supply control module for converting the electricity output by the thermoelectric power generation device into the power supply of the main control module and the storage battery;

the photovoltaic controller, the power supply control module and the storage battery are all connected with the main control module; the thermoelectric generation device is also connected with a storage battery to supply power to the storage battery; the photovoltaic power generation plate is connected with the storage battery; the storage battery is connected with the main control module; the photovoltaic power generation panel supplies power to the main control module through the storage battery.

In a specific embodiment, a cloud platform management system and an internet of things communication module are further arranged; the communication module of the Internet of things is respectively connected with the cloud platform control system and the master control module through communication signals; the main control module uploads the received temperature information to the cloud platform management system in real time; the user can send a control instruction to the main control module through the cloud platform.

In a specific embodiment, the photovoltaic cooling water temperature monitoring device is a photovoltaic panel circulating water temperature detection sensor; the photovoltaic cooling water control device comprises a photovoltaic power generation plate cooling water pump, a photovoltaic power generation plate cooling water inlet valve and a photovoltaic power generation plate cooling water outlet valve; the temperature of the cooling water of the photovoltaic power generation plate is monitored by a temperature detection sensor of the circulating water of the photovoltaic power generation plate and is input into a main control module; the photovoltaic power generation plate cooling water pump, the photovoltaic power generation plate cooling water inlet valve and the photovoltaic power generation plate cooling water outlet valve receive control signals from the main control module and control the inlet and outlet of the photovoltaic power generation plate cooling water.

In a specific embodiment, the temperature monitoring device of the thermoelectric generation sheet is a temperature sensor of a radiating surface and a heat absorbing surface of the thermoelectric generation sheet; the temperature difference cooling water control device comprises temperature difference cooling water, a temperature difference cooling water pump, a temperature difference cooling water inlet valve and a temperature difference cooling water outlet valve; the temperature sensors of the radiating surface and the heat absorbing surface of the thermoelectric generation sheet monitor the temperature difference of the thermoelectric generation sheet and input the temperature difference into the main control module; the control temperature difference cooling water pump, the temperature difference cooling water inlet valve and the temperature difference cooling water outlet valve receive control signals from the main control module and control the inlet and outlet of the temperature difference cooling water.

In this embodiment, the storage battery is a 12V lithium battery.

In this embodiment, the dc-ac converter is further included; the 12V lithium battery realizes charge and discharge through the DCAC inverter.

In this embodiment, the control module is a cloud platform control system, and the cloud platform control system is connected with the main control module through a 4G or 5G communication signal.

In the embodiment, the photovoltaic power generation heating water control system detects the temperatures of the surface and the back of the solar photovoltaic power generation panel in real time, introduces tap water or air conditioner cooling water to cool the solar photovoltaic power generation panel according to the detected trend of temperature change, and realizes that the solar photovoltaic power generation panel is in the maximum power generation efficiency state for most of the time through the combined schemes of time sharing, segmentation, PID algorithm, experience method and the like.

In this embodiment, the thermoelectric generation control device for controlling the thermoelectric generation device is used to raise the voltage of the semiconductor power generation sheet within the range of 0.8V to 3.6V to a stable voltage of 5.0V, and provide electric energy to the main control module. When the output power of the thermoelectric generation sheet is more than or equal to 20W, the power supply control device is started to raise the voltage of 5.0V to 13.2V while the stable voltage of 5.0V is maintained, and the storage battery is charged.

Example 3

More specifically, in one specific embodiment, the device further comprises a photovoltaic power generation plate cooling control device and a thermoelectric power generation control device; the photovoltaic power generation plate cooling control device is used for receiving the temperature signal from the photovoltaic cooling water temperature monitoring device, sending the temperature signal to the main control module, receiving the control signal from the main control module and controlling the photovoltaic cooling water control device to execute; the photovoltaic power generation plate cooling control device is used for receiving the temperature signal from the temperature monitoring device of the thermoelectric power generation sheet, sending the temperature signal to the main control module, receiving the control signal from the main control module and controlling the thermoelectric cooling water control device to execute; the master control module comprises an RS485 communication interface; the main control module is connected with the cooling water control device and the thermoelectric generation control device of the photovoltaic power generation panel through the RS485 communication interface respectively.

In a specific embodiment, the serial asynchronous half duplex communication mode adopts a standard MODBUS-RTU protocol.

In a specific embodiment, the touch display screen is used for directly operating the main control module by a user; the touch display screen is connected with the main control module.

In this embodiment, as shown in fig. 3, the working voltage of the master control module is 12V; the main control module can communicate with a photovoltaic power generation plate cooling water control device for controlling a photovoltaic power generation plate cooling device, a thermoelectric power generation control device for controlling a thermoelectric power generation device, a 4G internet of things communication module and other RS485 communication interface equipment with Modbus communication protocols through three paths of 485 communication interfaces, and a 1-path asynchronous serial communication interface UART is communicated with a touch screen display; 8 paths of digital-to-analog conversion interfaces of the thermocouple temperature measuring sensor are reserved, and 6 paths of power on/off output ports of the 12V electromagnetic valve are reserved.

In this embodiment, the power module circuit of the main control module performs voltage stabilization on +5v and +12v voltages respectively by using direct current voltages input in a wide range of 12V to 40V, and the +5v voltage mainly provides electric energy for a core control chip, a relay control circuit, an RS485 communication circuit, a liquid crystal display screen and other external access devices of the main control module. And the +12V voltage is mainly used for controlling the on and off of a normally open switch of the relay through a relay circuit, and providing power for the electromagnetic valve and the circulating water pump with the 12V working voltage.

In this embodiment, as shown in fig. 4, the +5v voltage stabilizing circuit uses an XH2596-5.0 voltage stabilizing chip as a power conversion microcontroller, a fixed frequency oscillator and a frequency compensation module are built in the controller, and the controller is matched with an external 47 μh inductor, a 1000 μf/25V capacitor and a schottky diode 1N5819, so that voltage conversion is stabilized at +5v by charging/discharging the combination of the inductor and the capacitor, and the maximum working current of the controller can reach 3A. After the external input power supply is disconnected, the electric energy is released to the positive electrode of the capacitor through the inductor, the electric energy of the capacitor is released to the positive electrode of the Schottky diode through the negative electrode of the capacitor, and the negative electrode of the Schottky diode is connected with the inductor, so that a closed loop is formed, and redundant electric energy is consumed internally.

In this embodiment, as shown in fig. 5, the +12v voltage stabilizing circuit uses an XH2596-12.0 voltage stabilizing chip as a power conversion microcontroller, a fixed frequency oscillator and a frequency compensation module are built in the controller, and the controller is matched with an external 47 μh inductor, a 1000 μf/25V capacitor and a schottky diode 1N5819, so that voltage conversion is stabilized at +5v by charging/discharging the combination of the inductor and the capacitor, and the maximum working current can reach 3A. After the external input power supply is disconnected, the electric energy is released to the positive electrode of the capacitor through the inductor, the electric energy of the capacitor is released to the positive electrode of the Schottky diode through the negative electrode of the capacitor, and the negative electrode of the Schottky diode is connected with the inductor, so that a closed loop is formed, and redundant electric energy is consumed internally.

In the embodiment, the RS485 communication interface of the main control module can realize automatic switching of receiving and transmitting RS485 communication signals; as shown in FIG. 6, the master control module comprises an asynchronous serial communication data output port and an asynchronous serial communication data input port; the communication circuit of the RS485 communication interface comprises a MAX485 master control chip, a triode Q1, resistors R1, R4 and R7 and an optical coupler; the pins b, c and e of the triode Q1 are respectively and sequentially electrically connected with an asynchronous serial communication data output port, RE# and DE pins DI; the asynchronous serial communication data input port is electrically connected with an R0 pin of the MAX485 master control chip; one end of the resistor R1 is grounded, and the other end of the resistor R1 is respectively and electrically connected with the pin B of the MAX485 master control chip, one end of the resistor R4 and the pin 1 of the optocoupler; the other end of the resistor R4 is respectively and electrically connected with the pin A of the MAX485 master control chip, one end of the resistor R7 and the pin 2 of the optocoupler; the other end of the resistor R7 is electrically connected with a +5V power supply; the MAX485 master control chip has the highest communication baud rate of 2.5Mbps and has the function of automatic data receiving and transmitting;

in the data transmission process, when TXD (MCU asynchronous serial communication data output port) transmits '0', triode Q1 is not conducted, MAX485 communication chips RE# and DE are high level ('1'), MAX485 communication chip enters a transmission mode, and MAX485 communication chip transmits low level ('0') of DI pin of MAX485 communication chip outwards through A, B pin. MCU is the master control module.

When TXD (MCU asynchronous serial communication data output port) sends "1", triode Q1 switches on, MAX485 communication chip RE# and DE are high level ("0"), MAX485 communication chip A, B pin gets into high resistance state, and resistance R7 pulls the A pin level high ("1"), and resistance R1 pulls the B pin level low ("0"), and MAX485 communication chip sends data "1" to outside through A, B pin at this moment.

In the data receiving process, the RS485 communication circuit keeps a high level '1' all the time, RXD (MCU asynchronous serial communication data output port) is in a data input state, a triode Q1 is conducted, RE# and DE of a MAX485 communication chip are high level ('0'), a pin A, B of the MAX485 communication chip enters a data high resistance state, and when the level of an A pin is more than the level of a B pin and the level differs by 0.2V, an RO pin outputs the high level ('1'). When the A pin level < the B pin level differs by 0.2V, the RO pin outputs a high level ("0"). The change in the RO pin output high level will be transmitted to the MCU through RXD (MCU asynchronous serial communication data input port) at data "1" and "0".

In this embodiment, the RS485 communication interface is a serial asynchronous half duplex communication mode, and adopts a standard MODBUS-RTU protocol, and the default communication data format is "n,8,1", and the baud rate is 9600bps. Various data information can be transmitted on a communication line, and one line can be simultaneously connected with 255 RS485 communication interface devices.

The flow of the MODBUS protocol query response data flow is shown in FIG. 10;

wherein, the inquiry message of the master device: the inquiry message frame includes a device address, a function code, a data information code, and a check code. The address code indicates the slave device to be selected; the function code tells the selected slave device what function to perform, e.g. function code 03 or 04 is a request from the slave device to read the registers and return their contents; the data segment contains any additional information that the slave device is to perform, and the check code is used to verify the correctness of a frame of information, and the slave device provides a method of verifying that the message content is correct, using the calibration rules of CRC 16.

Response message from the device: if the slave device generates a normal response, there are a slave address code, a function code, a data information code, and a CRC16 check code in the response message. The data information code includes data collected from the device: like register values or states. If an error occurs, the slave does not respond.

In the embodiment, a thermodynamic diagram of the temperature change of the back plate of the solar photovoltaic power generation plate is established through temperature data acquired by the thermocouple sensor, and simulation analysis is performed. The back of the solar photovoltaic power generation plate is cooled, and the flow of cooling water is controlled in real time according to the change of the temperature, so that the temperature of the solar photovoltaic power generation plate is ensured to be in a state of maximum power generation efficiency.

In this embodiment, as shown in fig. 7, the main control module further includes a main control module water pump and an electromagnetic valve control circuit; wherein U14 is PC817C type optocoupler, K7 is relay composition, U15 is water pump/solenoid valve power output interface. When the I/O port of the Main Controller (MCU) outputs 0 (the level is 0V), the light emitting diode in the optocoupler is conducted, so that the triode in the optocoupler is conducted, namely the 3 rd pin and the 4 th pin are conducted. At this time, the 1 st level of the relay is 4.7V, the relay is closed immediately, namely the 5 th pin and the 2 nd pin of the relay are conducted, and the 1 st pin of the U15 interface is at +12V voltage.

When the I/O port of the Main Controller (MCU) outputs 1 (the level is 5V), the LED in the optocoupler is not conducted, the level of the 1 st pin of the relay is 0V, the 5 th pin of the relay is conducted with the 3 rd pin, and the 1 st pin of the U15 interface is 0V voltage.

In this embodiment, as shown in fig. 8, the main control module further includes a thermocouple interface circuit; r37 is a thermocouple of the model MF52A103F3435, the resistance of the thermocouple is 10KΩ at +25 ℃, 69.6931KΩ at-20 ℃, 0.5336KΩ at +125 ℃, and the resistance change of the thermocouple is nonlinear in the temperature range of 20 ℃ to +125 ℃. R39 is a common 10k omega resistor, one end of the resistor is connected with a power supply +5V, the other end of the resistor is connected with a thermocouple, the other end of the thermocouple is connected with a power supply negative electrode, a voltage dividing function is formed at the middle connecting point of the resistor and the thermocouple, and when the resistance value of the thermocouple changes, the voltage value of the point also changes. The Main Controller (MCU) collects and converts the voltage of the connection point of the thermocouple and the resistor R39 through an analog-digital converter (A/D) of the main controller, and the thermocouple temperature data is calculated through a table lookup method.

In this embodiment, as shown in fig. 11, the Main Controller (MCU) collects and converts the voltage at the connection point of the thermocouple and the resistor R39 in fig. 5 through its 12bit high-precision analog-to-digital converter (a/D), and obtains corresponding data, where the data range is 0-4096. The converted data is carried into the program of the binary search method, and the temperature data with one decimal point can be obtained.

In this embodiment, as shown in fig. 12, a Master Controller (MCU) communicates with a 4G/5G internet of things communication module through an on-board RS485 interface, and the default communication data format is "n,8,1", and the baud rate is 115200bps. The Main Controller (MCU) splits, converts and CRC16 checks the data to be uploaded to the Internet of things cloud platform control system, stores the data in a specified data packet, and sends the data packet to the on-board RS485 communication module of the 4G/5G Internet of things communication module through the asynchronous serial communication port UART, so that the data can be uploaded.

In a specific embodiment, the main control module further comprises a 6-way water valve and a power output interface; the 6-way electromagnetic valve and the power output interface are respectively connected with the photovoltaic power generation plate cooling water pump, the photovoltaic power generation plate cooling water inlet valve, the photovoltaic power generation plate cooling water outlet valve, the temperature difference cooling water pump, the temperature difference cooling water inlet valve and the temperature difference cooling water outlet valve in a one-to-one correspondence manner; the main control module can directly control the photovoltaic power generation plate cooling water pump, the photovoltaic power generation plate cooling water inlet valve, the photovoltaic power generation plate cooling water outlet valve, the temperature difference cooling water pump, the temperature difference cooling water inlet valve and the temperature difference cooling water outlet valve through the 6-way electromagnetic valve and the power output interface.

In this embodiment, the water valves are all solenoid valves.

In a specific embodiment, an internet of things communication module is further provided; the communication module of the Internet of things is respectively connected with the cloud platform control system and the master control module through communication signals; the main control module uploads the received temperature information to the cloud platform management system in real time; the user can send a control instruction to the main control module through the cloud platform. In the embodiment, relevant temperature data, a water inlet valve and a water outlet valve working state of a solar photovoltaic power generation panel and a temperature difference power generation control device for controlling the temperature difference power generation device are uploaded to the cloud platform control system in real time, and meanwhile, the cloud platform control system can remotely switch the working states of the water inlet valve and the water outlet valve.

In a specific embodiment, the thermoelectric generation sheet temperature sensor comprises a thermoelectric generation sheet three-hot-face sensor for detecting a temperature difference and a heat absorption face temperature sensor for monitoring a heat absorption face temperature of the thermoelectric generation sheet.

The invention realizes the integration of the photoelectric conversion system, the photo-thermal conversion system and the thermoelectric conversion system based on the solar photovoltaic power generation plate, and improves the solar energy utilization efficiency. The system aims at maximizing the power generation efficiency, the heating water efficiency and the thermoelectric conversion efficiency of the solar photovoltaic power generation panel, water flows through the photovoltaic back panel to carry away the heat of the photovoltaic power generation panel, and the back panel temperature is controlled by controlling the water flow. The invention discloses a photovoltaic power generation and heating water control system which comprises a main control module, a photovoltaic controller, a photovoltaic power generation plate cooling water control device, a photovoltaic power generation plate cooling device, a thermoelectric power generation control device, a thermoelectric power generation device, a power supply control module and at least one thermocouple sensor, wherein the power supply control module is used for inputting electricity output by a photovoltaic power generation plate into a storage battery and converting the electricity output by the storage battery into power supply of the main control module, the photovoltaic power generation plate cooling water control device is used for controlling cooling water of a photovoltaic power generation and heating water system to flow in and flow out, the thermoelectric power generation control device is used for monitoring thermoelectric power generation of a thermoelectric power generation sheet, the power supply control module is used for converting the electricity output by the thermoelectric power generation device into power supply of the main control module and the storage battery, and the thermocouple sensor is used for monitoring local temperature of the photovoltaic power generation plate. Aiming at the problems that the local temperature of a photovoltaic power generation plate is too high, hot spots are generated and the power generation efficiency and the service life of a photovoltaic module are affected, the invention monitors the temperature of cooling water, and controls the cooling water pump of the photovoltaic power generation plate, the cooling water inlet valve of the photovoltaic power generation plate and the 1 st cooling water outlet valve of the cooling water of the photovoltaic power generation plate. The invention also monitors the temperature difference of the temperature difference power generation piece, controls the temperature difference power generation monitoring control module of the temperature difference cooling water pump, the temperature difference cooling water inlet valve and the temperature difference cooling water outlet valve, and realizes efficient temperature difference power generation; therefore, the method solves the problem of low power generation efficiency caused by overhigh local temperature of the photovoltaic power generation plate in the prior art, and has the characteristic of ensuring the state of maximum power generation efficiency.

Example 4

More specifically, as shown in fig. 9, in the flow of controlling the photovoltaic power generation and water heating control system of the present invention, after the main control module is started, the RS485 communication interface function, the thermocouple sensor data acquisition and conversion, the touch display screen interface, the electromagnetic valve/water pump power output interface are initialized, and then whether the RS485 communication interface is connected to the photovoltaic power generation cooling water control device or the thermoelectric power generation control device for controlling the thermoelectric power generation device is judged, if the RS485 communication interface is connected to the related device, related command reading data is sent or command switching of the working states of the electromagnetic valve and the water pump is sent according to the user command. And meanwhile, after the related temperature data and the working state of the electromagnetic valve/water pump are packaged, the temperature data and the working state of the electromagnetic valve/water pump are sent to the cloud platform control system through a communication module using 4G/5G communication signals.

Otherwise, judging and reading the temperature data of the thermocouples through the 8-path thermocouple communication interfaces reserved by the main control module, and switching the working state of the reserved 6-path 12V electromagnetic valve/water pump according to a user preset command. And meanwhile, related temperature data and the working state of the electromagnetic valve/water pump are packaged and then sent to the cloud platform control system through the 4G/5G communication module.

Example 5

As shown in fig. 13, a control method for generating hot water by photovoltaic power generation comprises the following specific steps:

S1, supplying power to a main control module through a photovoltaic power generation plate and a thermoelectric power generation device; monitoring the cooling water temperature of the photovoltaic power generation plate through a photovoltaic cooling water temperature monitoring device; monitoring the temperature difference of the thermoelectric generation sheet through a temperature monitoring device of the thermoelectric generation sheet; monitoring the local temperature of the photovoltaic power generation plate through a thermocouple sensor; the temperature of the thermoelectric generation sheet, the temperature information of cooling water of the photovoltaic generation plate and the local temperature information of the photovoltaic generation plate are received in real time through the main control module;

in this embodiment, the thermoelectric generation control device for controlling the thermoelectric generation device uses the temperature difference between the cooling water and the environment to directly convert the heat energy into the electric energy through the thermoelectric generation sheet, so as to improve the total efficiency of the system for solar energy utilization

S2, if the local temperature of the cooling water or the photovoltaic power generation plate is judged to be too high, a signal is sent to a photovoltaic power generation plate cooling device through a main control module, water inlet and outlet circulation of the photovoltaic power generation plate cooling water is controlled through a photovoltaic cooling water control device, the temperature of the photovoltaic power generation plate cooling water is reduced, and the photovoltaic power generation plate is cooled; if the temperature difference of the temperature difference power generation piece is insufficient, a signal is sent to the temperature difference power generation device through the main control module, and the water inlet and outlet circulation of the temperature difference cooling water is controlled through the temperature difference cooling water control device.

In a specific embodiment, the main control module further comprises a 6-way water valve and a power output interface; the 6-way electromagnetic valve and the power output interface are respectively connected with the photovoltaic power generation plate cooling water pump, the photovoltaic power generation plate cooling water inlet valve, the photovoltaic power generation plate cooling water outlet valve, the temperature difference cooling water pump, the temperature difference cooling water inlet valve and the temperature difference cooling water outlet valve in a one-to-one correspondence manner;

in the step S2, a photovoltaic power generation plate cooling water pump, a photovoltaic power generation plate cooling water inlet valve, a photovoltaic power generation plate cooling water outlet valve, a temperature difference cooling water pump, a temperature difference cooling water inlet valve and a temperature difference cooling water outlet valve can be directly controlled through the main control module through 6 paths of electromagnetic valves and a power output interface.

In the embodiment, the photovoltaic power generation plate is a single 670mm x 835mm solar photovoltaic power generation plate; as shown in fig. 12, each photovoltaic power generation panel is provided with 6 temperature measuring points where thermocouple sensors can be placed. The water valve adopts the solenoid valve, can directly pass through 6 way solenoid valve and power output interface direct control on or the state of closing through the master control module.

It is to be understood that the above examples of the present invention are provided by way of illustration only and not by way of limitation of the embodiments of the present invention. Any modification, equivalent replacement, improvement, etc. which come within the spirit and principles of the invention are desired to be protected by the following claims.

Claims (10)

1. A photovoltaic power generation heats water control system, its characterized in that: the device comprises a main control module, a photovoltaic power generation plate cooling device, a thermoelectric power generation device and at least one thermocouple sensor for monitoring the local temperature of the photovoltaic power generation plate;

the photovoltaic power generation plate cooling device is connected with the photovoltaic power generation plate; the temperature difference power generation device is connected with the main control module and supplies power to the main control module; the thermocouple sensor is arranged on the photovoltaic power generation plate and connected with the main control module;

the photovoltaic power generation plate cooling device comprises a photovoltaic cooling water temperature monitoring device for monitoring the temperature of the cooling water of the photovoltaic power generation plate and a photovoltaic cooling water control device for controlling the water inlet and outlet circulation of the cooling water of the photovoltaic power generation plate; the main control module is contacted with the output of the photovoltaic cooling water temperature monitoring device; the main control module is contacted with the input of the photovoltaic cooling water control device;

the thermoelectric generation device comprises a thermoelectric generation sheet for realizing thermoelectric generation through the temperature difference between cooling water and the environment, a thermoelectric generation sheet temperature monitoring device for monitoring the temperature difference of the thermoelectric generation sheet, and a thermoelectric cooling water control device for controlling the circulation of thermoelectric cooling water; the heat absorption surface of the thermoelectric generation sheet is connected with the photovoltaic power generation plate, and the heat dissipation surface of the thermoelectric generation sheet is cooled by temperature difference cooling water; the main control module is contacted with the output of the temperature monitoring device of the thermoelectric generation sheet; the main control module is contacted with the input of the temperature difference cooling water control device.

2. The photovoltaic power generation and water heating control system according to claim 1, wherein: the photovoltaic power generation system further comprises a storage battery, a photovoltaic controller and a power supply control module, wherein the photovoltaic controller is used for inputting electricity output by the photovoltaic power generation panel into the storage battery and converting the electricity output by the storage battery into power supply of the main control module, and the power supply control module is used for converting the electricity output by the thermoelectric power generation device into power supply of the main control module and the storage battery;

the photovoltaic controller, the power supply control module and the storage battery are all connected with the main control module; the thermoelectric generation device is also connected with a storage battery to supply power to the storage battery; the photovoltaic power generation plate is connected with the storage battery; the storage battery is connected with the main control module; the photovoltaic power generation panel supplies power to the main control module through the storage battery.

3. The photovoltaic power generation and water heating control system according to claim 2, wherein: the system is also provided with a cloud platform management system and an Internet of things communication module; the communication module of the Internet of things is respectively connected with the cloud platform control system and the master control module through communication signals; the main control module uploads the received temperature information to the cloud platform management system in real time; the user can send a control instruction to the main control module through the cloud platform.

4. The photovoltaic power generation and water heating control system according to claim 1, wherein: the photovoltaic cooling water temperature monitoring device is a photovoltaic panel circulating water temperature detection sensor; the photovoltaic cooling water control device comprises a photovoltaic power generation plate cooling water pump, a photovoltaic power generation plate cooling water inlet valve and a photovoltaic power generation plate cooling water outlet valve; the temperature of the cooling water of the photovoltaic power generation plate is monitored by a temperature detection sensor of the circulating water of the photovoltaic power generation plate and is input into a main control module; the photovoltaic power generation plate cooling water pump, the photovoltaic power generation plate cooling water inlet valve and the photovoltaic power generation plate cooling water outlet valve receive control signals from the main control module and control the inlet and outlet of the photovoltaic power generation plate cooling water.

5. The photovoltaic power generation and water heating control system according to claim 4, wherein: the temperature monitoring device of the thermoelectric generation sheet is a temperature sensor of a radiating surface and a heat absorbing surface of the thermoelectric generation sheet; the temperature difference cooling water control device comprises temperature difference cooling water, a temperature difference cooling water pump, a temperature difference cooling water inlet valve and a temperature difference cooling water outlet valve;

the temperature sensors of the radiating surface and the heat absorbing surface of the thermoelectric generation sheet monitor the temperature difference of the thermoelectric generation sheet and input the temperature difference into the main control module; the control temperature difference cooling water pump, the temperature difference cooling water inlet valve and the temperature difference cooling water outlet valve receive control signals from the main control module and control the inlet and outlet of the temperature difference cooling water.

6. The photovoltaic power generation and water heating control system according to claim 5, wherein: the main control module further comprises a 6-way water valve and a power output interface; the 6-way electromagnetic valve and the power output interface are respectively connected with the photovoltaic power generation plate cooling water pump, the photovoltaic power generation plate cooling water inlet valve, the photovoltaic power generation plate cooling water outlet valve, the temperature difference cooling water pump, the temperature difference cooling water inlet valve and the temperature difference cooling water outlet valve in a one-to-one correspondence manner; the main control module can directly control the photovoltaic power generation plate cooling water pump, the photovoltaic power generation plate cooling water inlet valve, the photovoltaic power generation plate cooling water outlet valve, the temperature difference cooling water pump, the temperature difference cooling water inlet valve and the temperature difference cooling water outlet valve through the 6-way electromagnetic valve and the power output interface.

7. The photovoltaic power generation and water heating control system according to claim 1, wherein: the device also comprises a photovoltaic power generation plate cooling control device and a thermoelectric power generation control device; the photovoltaic power generation plate cooling control device is used for receiving the temperature signal from the photovoltaic cooling water temperature monitoring device, sending the temperature signal to the main control module, receiving the control signal from the main control module and controlling the photovoltaic cooling water control device to execute; the photovoltaic power generation plate cooling control device is used for receiving the temperature signal from the temperature monitoring device of the thermoelectric power generation sheet, sending the temperature signal to the main control module, receiving the control signal from the main control module and controlling the thermoelectric cooling water control device to execute; the master control module comprises an RS485 communication interface; the main control module is connected with the cooling water control device and the thermoelectric generation control device of the photovoltaic power generation panel through the RS485 communication interface respectively.

8. The photovoltaic power generation and water heating control system according to claim 7, wherein: the main control module comprises an asynchronous serial communication data output port and an asynchronous serial communication data input port; the communication circuit of the RS485 communication interface comprises a MAX485 master control chip, a triode Q1, resistors R1, R4 and R7 and an optical coupler; the pins b, c and e of the triode Q1 are respectively and sequentially electrically connected with an asynchronous serial communication data output port, RE# and DE pins DI; the asynchronous serial communication data input port is electrically connected with an R0 pin of the MAX485 master control chip; one end of the resistor R1 is grounded, and the other end of the resistor R1 is respectively and electrically connected with the pin B of the MAX485 master control chip, one end of the resistor R4 and the pin 1 of the optocoupler; the other end of the resistor R4 is respectively and electrically connected with the pin A of the MAX485 master control chip, one end of the resistor R7 and the pin 2 of the optocoupler; the other end of the resistor R7 is electrically connected with a +5V power supply;

During the data transmission process:

when the asynchronous serial communication data output port is 0, the triode Q1 is not conducted, the MAX485 communication chip RE# and DE are high level, the MAX485 communication chip enters a transmission mode, and at the moment, the MAX485 communication chip transmits the low level of the DI pin of the MAX485 communication chip outwards through the A, B pin of the MAX485 communication chip;

when the asynchronous serial communication data output port is 1, the triode Q1 is conducted, RE# and DE of the MAX485 communication chip are high level, a pin A, B of the MAX485 communication chip enters a high-resistance state, at the moment, the level of the pin A is pulled up by the resistor R7, the level of the pin B is pulled down by the resistor R1, and at the moment, the MAX485 communication chip sends data 1 to the outside through the pin A, B;

in the course of the data reception process,

the asynchronous serial communication data output port always keeps a high level '1', the asynchronous serial communication data input port is in a data input state, the triode Q1 is conducted, pins RE# and DE of the MAX485 communication chip are in a high-level MAX485 communication chip A, B and enter a data high-resistance state, and at the moment, when the level of an A pin is more than the level of a B pin and the level of a phase difference is 0.2V, the RO pin outputs a high level; when the level of the pin A is less than the level of the pin B by 0.2V, the pin RO outputs a high level; the RO pin outputs high level change, and the data 1 and 0 are transmitted to the main control module through the asynchronous serial communication data input port.

9. A control method for photovoltaic power generation and heating water is characterized by comprising the following steps: the method comprises the following specific steps:

s1, supplying power to a main control module through a photovoltaic power generation plate and a thermoelectric power generation device; monitoring the cooling water temperature of the photovoltaic power generation plate through a photovoltaic cooling water temperature monitoring device; monitoring the temperature difference of the thermoelectric generation sheet through a temperature monitoring device of the thermoelectric generation sheet; monitoring the local temperature of the photovoltaic power generation plate through a thermocouple sensor; the temperature of the thermoelectric generation sheet, the temperature information of cooling water of the photovoltaic generation plate and the local temperature information of the photovoltaic generation plate are received in real time through the main control module;

s2, if the local temperature of the cooling water or the photovoltaic power generation plate is judged to be too high, a signal is sent to a photovoltaic power generation plate cooling device through a main control module, water inlet and outlet circulation of the photovoltaic power generation plate cooling water is controlled through a photovoltaic cooling water control device, the temperature of the photovoltaic power generation plate cooling water is reduced, and the photovoltaic power generation plate is cooled; if the temperature difference of the temperature difference power generation piece is insufficient, a signal is sent to the temperature difference power generation device through the main control module, and the water inlet and outlet circulation of the temperature difference cooling water is controlled through the temperature difference cooling water control device.

10. The method for controlling the photovoltaic power generation and heating water according to claim 9, wherein: the main control module further comprises a plurality of electromagnetic valves and a power output interface; the electromagnetic valves and the power output interfaces are respectively and correspondingly connected with the photovoltaic cooling water temperature and monitoring control device and the photovoltaic cooling water control device and the temperature difference cooling water control device;

In the step S2, the photovoltaic cooling water control device and the temperature difference cooling water control device can be directly controlled through a plurality of paths of electromagnetic valves and power output interfaces directly through the main control module.