RU2810876C1 - Microcontroller for adjusting coolant flow of solar power plant - Google Patents

Abstract

FIELD: solar power plant.

SUBSTANCE: used to regulate the flow of coolant in the hydraulic system of a solar power plant depending on the temperature of the coolant at the outlet of solar modules at the points where the temperature sensor is located. The microcontroller consists of a single-chip microcontroller, a control and performance monitoring circuit, an indication and alarm circuit, a USB interface, an AC/DC power supply, an RS-485 interface and a GSM/GPRS wireless interface for transmitting short messages about the status and errors in the operation of the solar cooling system power plant, a power supply to ensure the operation of the RS-485 interface and the GSM/GPRS wireless interface, an analog part of the measuring circuits containing a reference voltage source, an analog multiplexer, a temperature signal amplifier and a flow rate measurement circuit, a coolant level measurement circuit for processing the signal from a low coolant level sensor and an inverter consisting of several DC/DC converters, a control circuit for generating PWM signals and galvanic isolation, power switch drivers, power switches and a low-pass filter to obtain a standard supply voltage for hydraulic pumps from the voltage generated by the solar power plant.

EFFECT: providing expanded operational capabilities of a solar power plant by improving the parameters of the microcontroller.

1 cl, 2 dwg

Description

The present invention relates to circuitry and can be used to regulate the flow of coolant in the hydraulic system of a solar power plant (SPP) depending on the temperature of the coolant at the output of solar modules at the locations of temperature sensors in order to expand the operational capabilities of the SPP by improving the parameters of the microcontroller.

An intelligent control system for a heat exchange unit is known (patent CN No. 204345797 dated December 19, 2014), containing a network of primary water supply pipelines, a network of secondary heat supply pipelines, a circulation pump, a water make-up pump and a controller. The pressure sensor and temperature sensor on the main water supply network are connected to the signal input of the controller, and the pressure sensor and temperature sensor on the main heating network are connected to the feedback signal input of the controller. The output end of the controller is connected to the electric control valve, the circulation pump frequency converter and the water supply pump frequency converter.

The disadvantage of this device is:

- not optimized for use in solar energy systems (used in the field of heating and hot water supply of multi-apartment residential buildings)

An automated individual heating point with a dependent connection of the heating system and a closed hot water supply system is known (RF patent No. 2673758 dated 05/05/2017), containing forward and return pipelines of the heating network, supply and return pipelines of the heating system, temperature sensors for the supply and return water of the system heating, outdoor air temperature sensors, water temperature sensor for hot water supply, temperature sensors for forward and return water of the heating network, internal air temperature sensors in the room, circulating water temperature sensor for hot water supply, between the forward and return pipelines of the heating network, a two-stage hot water water heater, connected in a mixed circuit, between the direct pipeline of the heating network and the first stage of the hot water supply water heater, a block for regulating the water temperature for hot water supply, on the pipeline of the circulating water supply, a block for regulating the temperature of the circulating water supply for hot water, an electronic regulator for the temperature of the room air and hot water supply, the inputs of which connected to temperature sensors for supply and return water of the heating system, direct and return water of the heating network, water temperature for hot water supply and circulating water temperature for hot water supply, indoor air temperature in the room, outdoor air temperature, and the outputs are connected to the system return water temperature control unit heating, a heating system supply water temperature control unit, a hot water supply temperature control unit and a hot water supply temperature control unit, characterized in that the heating system return water temperature control unit is installed between the supply and return pipelines of the heating system, and the temperature control unit heating system supply water - on a direct pipeline of the heating network.

The disadvantage of this device is:

- not optimized for use in solar energy installations (used in the field of heating and hot water supply of multi-apartment residential buildings) - does not provide the transmission of short messages (SMS) via GSM cellular communications about the status of the water supply system and errors in its operation to the mobile phones of personnel serving the heating station .

- electronic units and heat station regulators do not have the ability to exchange data with a PC and be controlled by it.

An automatic regulator of the hydraulic mode of a heating network is known (RF patent No. 2678225 dated 05/05/2017), including an automatic regulator of the hydraulic mode of a heating network, including forward and return pipelines of a heating network, a return water temperature sensor of a heating network, an outside air temperature sensor, characterized in that that a coolant flow control unit is installed on the supply pipeline of the heating network, an electronic regulator of the hydraulic mode of the heating networks has been introduced, the inputs of which are connected to return water and outside air temperature sensors, and the outputs are connected to the coolant flow control unit.

The disadvantage of this device is:

- not optimized for use in solar energy systems (used in the field of heating and hot water supply to populated areas).

- does not provide the transmission of short messages (SMS) via GSM cellular communication about the state of the water supply system and errors in its operation to the mobile phones of personnel serving the heating station.

A block heat consumption control module is known (RF patent No. 187444 dated November 2, 2018), which includes a heat consumption control block module containing an electronic programmable block controller connected to a circulation pump, a pressure switch sensor to protect the pump from dry running and a control valve with an electric drive. , coolant temperature sensors in the supply and return pipelines, characterized in that it additionally contains a safety valve against excess pressure in the heating system installed in the return pipeline, and a coolant leak detection sensor connected through a coolant leakage control unit with an electronic programmable controller unit made with the ability to receive a signal from the ambient air temperature sensor and the air temperature sensor in the control room of the building, while the leakage control unit is equipped with a GSM modem to transmit an alert to the dispatcher console. The disadvantage of this device is:

- not optimized for use in solar energy systems (used in the field of heating and hot water supply of multi-apartment residential buildings).

- implemented in the form of several blocks that perform their functions. Closest in technical essence to the proposed

The device is a microcontroller for adjusting the coolant flow of a solar power plant (SPP) (RF patent No. 184637, 2018).

Microcontroller for adjusting the coolant flow of a solar power plant, consisting of an analog part of the measuring circuits containing a reference voltage source, an analog multiplexer, a temperature signal amplifier, flow and temperature measurement circuits, a single-chip microcontroller, a control circuit and monitoring the performance of the microcontroller, an indication and alarm circuit, USB -interface and AC/DC power supply, characterized in that the electronic circuit is made on a printed circuit board installed in a sealed aluminum case, with two thermal leads located on the case, through which the microcontroller connection wires are routed, ending with terminals, a waterproof power switch and a USB socket .

The disadvantage of this device is:

- to power hydraulic pumps with standard voltage (~~220 V 50 Hz), external power is required (not received from the SEU itself)

- there is no possibility of sending short SMS messages about the state of the hydraulic cooling system of the SEU and errors in its operation to the mobile phones of personnel servicing the installation.

- there is no possibility to receive a signal from the low coolant level sensor.

- there is no possibility to exchange data with a PC via the RS-485 interface.

- there is no ability to exchange data via the GSM/GPRS wireless interface with mobile devices (laptop, tablet, smartphone).

The purpose of the proposed utility model is to expand operational capabilities by improving the parameters of the microcontroller, namely:

- obtaining a standard voltage for powering hydraulic pumps from the voltage generated by the control unit itself;

- transmission of short messages (SMS) about the state of the hydraulic cooling system of the power plant and errors in its operation to the mobile phones of personnel servicing the installation;

- expansion of interfaces for data exchange (the RS-485 interface and the GSM/GPRS wireless interface are added to USB);

- processing the signal from the low coolant level sensor.

The technical result is that by regulating the hydraulic pumps included in the system, smooth control of the flow of coolant (coolant) in the hydraulic cooling system of the SPP is ensured, depending on its temperature at the outlet of the solar modules.

The technical result is achieved by the fact that the microcontroller for adjusting the coolant flow (MCROZH), consisting of a single-chip microcontroller, a control and performance monitoring circuit, an indication and alarm circuit, a USB interface, an AC/DC power supply and an analog part of the measuring circuits containing a reference source voltage, an analog multiplexer, a temperature signal amplifier, a flow rate measurement circuit, an RS-485 interface, a GSM/GPRS wireless interface, an additional power supply and an inverter consisting of several DC/DC converters, a control circuit for generating PWM signals and galvanic isolation were additionally introduced, drivers of power switches, power switches and a low-pass filter, and a circuit for measuring the coolant level was additionally introduced into the analog part of the measuring circuits.

The GSM/GPRS wireless interface is designed for transmitting short messages to the mobile phones of SEU maintenance personnel about the status and errors in the operation of the cooling system of a solar power plant using a specialized module Ml O from Quectel with output to an external GSM antenna;

When connected to a PC via a USB interface, RS-485 interface or wireless GSM/GPRS interface, it is possible to configure the parameters of the MRR and monitor the readings of all sensors and operating modes using specialized software;

The coolant level measurement circuit is designed to process the signal from the low coolant level sensor;

An additional power supply is introduced to ensure the operation of the RS-485 interface and the GSM/GPRS wireless interface;

To use the GSM/GPRS wireless interface, the SIM card is installed in a special slot.

The electronic circuit of the main unit is made on two printed circuit boards installed in a polycarbonate case, which has a connector for connecting the device, indicators of operating modes and faults, a waterproof power switch, a connector for connecting a GSM antenna and a lockable hole for connecting a USB cable and for installing a SIM -cards.

The inverter converts DC voltage=310±5%V generated by the SEU into alternating sinusoidal voltage -220+10%-15%V with a frequency of 50 Hz to obtain a standard supply voltage for hydraulic pumps;

DC/DC converters from the voltage generated by the solar power plant receive several DC voltages to power all the nodes of the MRR.

The control circuit, generation of PWM signals and galvanic isolation performs the following functions:

- turns on/off the power part of the inverter using an external signal “Signal On”;

- generates PWM signals with a duty cycle that varies according to a sinusoidal law, and outputs them to power switches through drivers;

- galvanically isolates functional units with power supply from units with low-current power supply = 3.3 V.

Power switch drivers set the necessary operating modes of the “Upper” and “Lower” transistor switches.

The power switches are a bridge circuit of four MOSFET transistors with an N-channel for switching the power input voltage via PWM control signals to the load through a low-pass filter.

A low-pass filter (LPF) is a sinusoidal filter that allows you to obtain a 50 Hz sinusoidal signal at the output from a power PWM signal and attenuate its harmonic components.

The electronic circuit of the inverter is made on two printed circuit boards installed in an aluminum housing, which has connectors for connecting the device and a waterproof backlit power switch.

The essence of the proposed invention is shown in Figures 1, 2.

Figure 1 shows the functional diagram of the main block of the MRRZH SEU, where:

1 - Analog multiplexer

2 - Temperature signal amplifier

3 - Reference voltage source

4 - Scheme for measuring flow speed

5 - Scheme for measuring the coolant level

6 - Indication and sound signaling diagram

7 - AC/DC power supply

8 - Additional power supply

9 - USB interface

10 - RS-485 interface

11 - GSM/GPRS wireless interface

12- Single-chip microcontroller

13 - Control and performance monitoring diagram

Figure 2 shows the functional diagram of the inverter MRROZH SEU, where:

14 - Converter = 310 V / = 12 V

15 - Converter = 12 V / = 5 V

16 - Converter = 12 V / = 3.3 V

17 - Control circuit, generation of PWM signals and galvanic isolation

18 - Power key drivers

19 - Power keys

20 - Low pass filter (LPF)

The device operates as follows: Power sources 7 and 8 receive several DC voltages from the voltage generated by the SEU to power all nodes of the MRRZH. Converters 14, 15 and 16 from the voltage generated by the SEU receive several DC voltages to power all inverter components. The signal from the temperature sensor of the solar power plant is fed to analog multiplexer 1, where the signal from the desired sensor is selected for subsequent processing. Next, the selected signal is sent to temperature signal amplifier 2 for amplification and scaling. The signal is then fed to one of the channels of the analog-to-digital converter (ADC) built into the single-chip microcontroller 12. To operate the temperature signal amplifier 2 and the ADC, the reference voltage source 3 generates a highly stable voltage of 4.1 V. At the same time, passing through the corresponding flow rate measurement circuit 4, a coolant flow rate signal is supplied to another ADC channel, and a coolant level signal is supplied to the input of single-chip microcontroller 12 through the corresponding coolant level measuring circuit 5 to another ADC channel. Signals from temperature sensors, flow sensors and coolant level sensors of a solar power plant are digitized into the ADC of single-chip microcontroller 12. Then, in single-chip microcontroller 12, using appropriate software, the values of all temperatures, flow rates and coolant levels are calculated. After calculating the temperature value, if it is necessary to turn on the pump, the “Signal On” signal of the inverter is generated. Next, when calculating the temperature values, flow rate and coolant level according to the corresponding laws and algorithms implemented in the device software, PWM signals are generated to control the coolant pumps of the solar power plant. The control circuit, generating PWM signals and galvanic isolation 17 turns on/off the power part of the inverter using an external signal “Signal on”, generates PWM signals with a duty cycle varying according to a sinusoidal law and outputs them to the power switch drivers 18, which set the necessary modes operation of transistor switches “Upper” and “Lower” 19. Also, the control circuit, generation of PWM signals and galvanic isolation 17 galvanically isolates functional units with power supply from units with low-current power supply. Power switches 19, which are a bridge circuit of four MOSFET transistors with an N-channel, switch the power input voltage via PWM control signals to the load through a low-pass filter 20. Throughout the entire working process, signals are generated in the single-chip microcontroller for the indication circuit and the sound signaling 6. USB interface 9 and RS-485 interface 10 convert the UART interface built into the single-chip microcontroller 12 into USB and RS-485 interfaces for connecting the MRRZH to a PC. In case of malfunctions, the GSM/GPRS 11 wireless interface via the GSM mobile network transmits signals about malfunctions of the hydraulic cooling system in the form of SMS messages to mobile phones, the numbers of which can be entered using specialized software when connecting the main unit of the MRROS SEU to a PC via USB- interface 9 or RS-485 interface 10. Control and performance monitoring circuit 13 controls the operation of single-chip microcontroller 12, indication and sound signaling circuit 6 and PWM signal outputs. When the single-chip microcontroller 12 fails, the control and performance monitoring circuit 13 switches to the indication and sound signaling circuit 6 and the PWM signal outputs and brings them to the appropriate predetermined state through a certain algorithm.

Claims (1)

Microcontroller for adjusting the coolant flow of a solar power plant, consisting of a single-chip microcontroller, a control and performance monitoring circuit, an indication and alarm circuit, a USB interface, an AC/DS power supply and an analog part of the measuring circuits containing a reference voltage source, an analog multiplexer, a signal amplifier temperature and a circuit for measuring flow rate, characterized in that the analog part of the measuring circuits includes a circuit for measuring the coolant level for processing the signal from the low coolant level sensor, and an RS-interface is additionally introduced into the microcontroller for adjusting the coolant flow of the solar power plant. 485 and a GSM/GPRS wireless interface for transmitting short messages about the status and errors in the operation of the cooling system of a solar power plant, a power supply to ensure the operation of the RS-485 interface and the GSM/GPRS wireless interface and an inverter consisting of several DC/DC converters, circuits controls for generating PWM signals and galvanic isolation, power switch drivers, power switches and a low-pass filter to obtain a standard supply voltage for hydraulic pumps from the voltage generated by the solar power plant.