UA114663C2 - A system for management of electric energy produced by photovoltaic cells - Google Patents

Abstract

A system for management of electric energy which is produced by photovoltaic cells which contains mutually interconnected an energy consumption control unit (2), a control unit (8) and a heating unit (9), which is equipped with a temperature measuring unit (91) and with at least one heating element (92) which is modified for liquid heating, where the essence of the invention is the fact that the energy consumption control unit (2) contains a DC control unit (21) and an AC control unit (22) and is partly connected to an AC power supply (10) either directly and/or through a secondary source of AC voltage (12) and partly is interconnected with a photovoltaic unit (1) which emits direct voltage, namely through a primary source of DC voltage (6) and/or through in series connected an output measuring unit of current and voltage (5), a DC/DC converter (4) and an input measuring unit of current and voltage (3), whereas also the control unit (8) is connected not only through a galvanic way separated secondary source of DC voltage (7) to the photovoltaic unit (1) but also through the galvanic way separated primary source of AC voltage (11) to the AC power supply (10).

Description

Technical level

The invention relates to the field of efficient use of renewable energy sources, when solar radiation is converted into electrical or thermal energy by means of photovoltaic devices, and relates to schemes of systems for controlling electrical energy produced by photovoltaic cells, which contain interconnected electronic components designed to control, use and store the received energy.

Known state of the art

A number of systems are known that use the energy produced by photovoltaic cells.

For example, documents 54873480 A, EK2485827 A1, О54649334A describe various systems that, with the help of interconnected electronic components, have the ability to control electrical energy and transfer the generated energy from photovoltaic panels to the electrical distribution system to equipment or devices designed for energy conservation. Autonomous energy systems are also known, in which only the energy obtained from photovoltaic panels is fully used, in the end, the excess energy is stored in batteries or in another energy storage device. One of the most widely used solutions for managing electrical energy is the installation of a converter in the system. The converter converts direct current into alternating current and provides a series connection of the system to the electrical system, ultimately, the energy is consumed in the equipment, similarly to if it were connected to the distribution system. There are known converters that use MPRT maximum load point monitoring (monitoring of the maximum power point) to increase efficiency.

Systems equipped with such converters have the ability to operate in the operating mode without connection to the electrical system, when either all the energy produced is consumed and no load is supplied to the external distribution system, or the resulting load is supplied to the electrical system and combined with its own consumption.

The disadvantage of this system is that there are losses on the converter as a result of energy conversion.

From document C220110582 AZ, a method of effective switching of the load of a photovoltaic generator to an active load and a device for performing this is known

From a method in which the output load of the photovoltaic generator is stored in a capacitor, and this load is then switched to an active load by means of a DC converter switch. The commutation of the DC converter is carried out by pulse width modulation, PWM, which is regulated by an algorithm depending on the height of the alternating current voltage at the output of the photovoltaic generator, while the instantaneous value of the load is determined continuously. The disadvantage of this solution is the structure of this system, when the capacitor is basically permanently connected to the source, and then the DC converter is connected to the active load using a PWM controller. From the point of view of interference, it is very disadvantageous when the load has an almost rectangular shape of the voltage and current curve, which is set by the PWM frequency and the value of the capacitor voltage with respect to the load. The PWM parameters depend on the input voltage on the panels and the active load. If there is a change in the resistance value, the algorithm used is quite imprecise. In addition, the energy converted in this way is practically unsuitable for any purpose, except for conversion into heat in an active load. Last, but not least, there is a high voltage load on the capacitor, which negatively affects its service life. Another disadvantage of this system is the lack of any regulation schemes that make it possible to use the energy obtained in this way.

Water is quite a suitable medium for saving the received energy. In households, for example, electric heaters are used to prepare hot water, which are based on the principle of a water tank and a heating unit that heats water. Documents C225157 01, 0222505 01, 0222504 01, 0057429719 B1, EN2604322A1 describe a device that uses electrical energy obtained from photovoltaic panels to heat water. The disadvantage of these solutions is that there is no monitoring of the point of maximum load of MPRT, which leads to significant losses due to the fact that the resistance of the device is not regulated in relation to the resistance of the source, and the power system cannot effectively use the received load. Document 055293447 describes a system with maximum load monitoring, which is performed by switching the active load with two values, but this equipment does not allow operation in the so-called autonomous mode, when only the energy obtained from the photovoltaic panels is used.

The purpose of the present invention is to create a new system for controlling electricity produced by photovoltaic cells, which would allow efficient use of the received energy, especially in the direct current mode, when there are no energy losses due to the conversion of direct current to alternating current. The system is adjusted to monitor the point of maximum load of MRRT, it is equipped with devices that are designed to use excess energy, and it is equipped with electronic components that serve to convert direct current to alternating current when necessary. The system is also made with the possibility of control from the main control element, and can work in autonomous power consumption mode.

The essence of the invention

The objective is largely achieved in the present invention, which proposes a system for controlling electrical energy produced by photovoltaic cells, which includes interconnected energy consumption control units, a control unit and a heating unit equipped with a temperature measurement unit, and at least one a heating element that is modified to heat a liquid, wherein the power consumption control unit includes a DC control unit and an AC control unit, and is partially connected to an AC source, either directly and/or via an auxiliary source AC voltage is partially connected to a PV unit that produces DC, namely through the main DC voltage source and/or through a series-connected current and voltage output unit, DC converter and current and voltage input unit, at the same time, the control unit will also burn provided not only through a galvanically isolated auxiliary DC voltage source with a photovoltaic unit, but also through a galvanically isolated main AC voltage source with an AC power supply.

Advantageously, the DC control unit of the power consumption control unit, configured to operate in a DC mode, comprises a DC fuse and a DC relay connected to a DC thermostat, the DC fuse being connected via the output measurement unit with a DC converter, and the DC relay is reciprocal

It is related to the heating unit.

Similarly, it is advantageous when the DC control unit of the power consumption control unit, designed to operate in AC mode, consists of an AC fuse and an AC relay connected to an AC thermostat, wherein the AC fuse with connected to the AC power source and the AC relay is interconnected with the heater unit.

Optimally, the DC fuse and AC fuse of the power consumption control unit are interconnected through the control protection element, with the control protection element connected to the temperature measurement unit, the fuse, the DC power relay, and the AC power relay .

In a preferred arrangement, the DC-to-DC converter is partly connected to the main DC voltage source, partly to the control unit and partly comprises a main switch and an auxiliary switch connected to each other, with a parallel circuit near the auxiliary switch having an integrated inductive element connected in parallel to capacitor and load.

It is also advantageous when the energy consumption control unit is equipped with a charging unit, which is partially formed with a charging relay and a charging control device, and is partially connected to at least one energy accumulator, the energy accumulator being interconnected with a converter that is modified to supply energy to the network

In the optimal case, there is an additional module connected to the power consumption control unit, as well as to the control unit, which consists of a UPS (uninterruptible power supply) relay, and an input current measuring element and a UPS control unit are connected in parallel to it, while the input the measuring element is connected to the AC power supply, and the UPS relay is interconnected to the converter, which is preferably a double-conversion UPS type.

Finally, it is advantageous when the control unit is equipped with an intelligent remote control sensor to detect off-peak electricity and/or a communication module to ensure communication with the main system, while it is equipped with a storage medium to record the order of the system.

With the help of the present invention, compared to the existing state of the art, a higher efficiency has been achieved, which consists in the fact that the control system for the electricity received from photovoltaic cells is designed for the efficient use of the received electricity, especially when the energy is used in the direct current mode, and with the help of a direct current converter, MRRT monitoring can be carried out continuously. The system is also designed to use excess energy, when the energy is stored in batteries and/or used to heat a liquid and at the same time also to convert the direct current, which is obtained from the photovoltaic panels, into alternating current.

Description of drawings

Specific examples of the proposed solution are schematically shown in the attached drawings, in which: in fig. 1 shows a schematic diagram of the system in the configuration for heating water, in fig. 2 shows a schematic diagram of the system in full configuration, in fig. C shows a diagram of a direct current converter and in fig. 4 shows the schematic diagram of fuses.

The drawings that illustrate this invention and sequentially describe examples of specific schemes do not in any way limit the scope of protection mentioned in the description, but only explain the essence of the invention.

Examples of implementation of the invention

The control system for electrical energy produced by photovoltaic cells mainly includes an autonomous installation according to fig. 1, the photovoltaic unit 1, which is connected in parallel with the power consumption control unit 2, and the connection is made partly through the series-connected input unit From current and voltage measurement, the converter 4 direct current to constant output unit 5 current and voltage measurement, and partly through the main source 6 DC voltage.

The DC to DC converter 4 is designed in such a way that the maximum load always remains constant, and is additionally connected to the main DC voltage source 6 and to the control unit 8. The control unit 8 is then connected to

From the energy consumption control unit 2, as well as through the galvanically decoupled auxiliary source 7 of direct current voltage - to the photovoltaic unit 1. The energy consumption control unit 2 contains two thermoregulation units 21, 22, which are connected to the heating unit 9. The heating unit 9 is made with a temperature measuring unit 91 and a heating element 92, which is designed to heat the liquid, while the heating unit 9 is at the same time connected to the control unit 8. The DC control unit 21 of the power consumption control unit 2, which operates in the DC voltage mode, is made with a DC fuse 211, a DC relay 212, and a DC thermostat 213, and is connected through the measurement output unit 5 to the transducer 4 direct current into direct current. The AC control unit 22 of the power consumption control unit 2 consists of an AC fuse 221, an AC relay 222, and an AC thermostat 223, and is connected to an AC power source 10. The control unit 8 is then connected to the AC power source 10 through the galvanically decoupled main AC voltage source 11, and the overall energy consumption control unit through the auxiliary AC voltage source 12.

As shown in fig. 2, the system, which works in autonomous mode as well as in island energy mode, is equipped with an energy consumption control unit 2 with an integrated charging unit 23, which is made of a charging relay 231 and a charging control device 232, and is connected to an energy accumulator 13, at the same time, the battery 13 is connected to the inverter 15, which serves to select the power source. An additional module 14 is also connected to the power consumption control unit 2, which consists of a UPS relay 141 (uninterruptible power supply), to which an element 142 for measuring the input current and a UPS control unit 143 are connected in parallel, while the additional module 14 is also connected to current converter 15. The control unit 8 is also equipped with both an intelligent remote control sensor 17 to detect off-peak current and a module 18 to provide communication with the main system using a selected interface, for example, a universal serial data bus (058), E (Shegpei, K5232, K5485, UMIII,

Both Wi-Fi and information carrier 19 for recording the order of system operation, for example, the amount of energy produced or consumed, current values, voltage or temperature.

DC converter 4, shown in fig. 3, contains an interconnected main switch 41 and an auxiliary switch 42, which are made of M-type MOSFETs operating in two states, either on or off. Near the auxiliary switch 42, a parallel circuit is made with an integrated inductive element 43, to which a capacitor 44 and a load 45 are connected in parallel.

In fig. 4 shows a scheme of thermal protection, which is made with a mutually integrated DC fuse 211 and an AC fuse 212 of the power consumption control unit 2. Fuses 211, 212 contain an element 100 for control protection, which receives power from the main source 6 of direct current voltage and/or from an auxiliary source 12 of alternating current voltage, while a device 101 for measuring temperature, a fuse 102 is connected to the element 100 for control protection , DC power relay 103 and AC power relay 104.

The direct current produced in the photovoltaic unit 1 is partially supplied to the current and voltage input device C, and then to the DC-to-DC converter 4, and is partially routed through the auxiliary DC voltage source 7 to the control unit 8, and partially routed through the main DC voltage source 6 to the power consumption control unit 2, as well as to the DC-to-DC converter 4. The function of the synchronous DC-to-DC converter 4 is that the input voltage is sent through two series-connected switches 41, 42, when in the case of the main switch 41 being on, the current does not enter the auxiliary switch 42, but is sent through a parallel circuit through an inductive element 43 into the capacitor 44 and the load 45. The inductive element 43 acts as a device, and this leads to a linear increase in the current and an increase in the voltage on the capacitor 44. In the case when the main switch 41 is turned off, this leads to the simultaneous on state of the auxiliary switch 42, and the inductive element 43 begins to act as a source, which corresponds to the voltage polarity switching, when the current flows from the inductive element 43 to the capacitor 44 and the load 45, and at the same time the voltage decreases linearly. The process is repeated periodically with a frequency of Her.

By changing the on/off period of individual switches 41, 42, it is possible to change the voltage on the load 45 from Odo Ogu to find the point of maximum efficiency

MRR. From the photovoltaic unit 1, the actual value of the current and voltage is found, and at each moment the output signal received from the photovoltaic unit 1 is calculated, while the time of the on state of the switches 41, 42 changes in the case of an output voltage corresponding to the requirement of the maximum output signal created by the photovoltaic block 1. The output current from the DC to DC converter 4 is sent through the output device 5 for current and voltage measurement to the DC control block 21 of the energy consumption control block 2. In this way, the processed energy enters the energy consumption control block 2, while the block 8 management must make a decision on the further use of energy. The main device for supplying energy either from the photovoltaic unit 1 or from the alternating current power supply unit 10 is the heating unit 9, while for the separation of direct and alternating current, galvanic isolation is performed in the auxiliary source of direct current voltage 7, as well as in the main source of voltage 11 AC control unit 2 and power consumption control unit 2, when DC control unit 21 and AC control unit 22 are equipped with DC relay 212 and AC relay 222, which provide voltage resistance of the contacts. The thermostats 213, 223 in the control units 21, 22 make it possible, in the event that the temperature in the heating unit 9 is lower than the value set by the user, to turn on the DC relay, and energy from the AC power supply unit 10 is sent to the heating element 92. DC relay 212, the energy from the photovoltaic unit 1 is sent to the heating element 92. In this case, the user uses the energy from the AC power supply unit 10 to heat water in the event that the energy from the sun is not sufficient, or in the event that the intelligent remote control sensor determines low electricity tariff. If the temperature in the heating unit 9 reaches the required value, the heating from the AC power supply unit 10 is stopped, and the energy obtained from the photovoltaic unit 1 is directed to another use.

The energy received from the photovoltaic unit 1 or from the AC power unit 10 can be directed to the energy consumption control unit in the charging unit 23 and/or directed to the additional module 14. In the charging unit 23, the energy is directed to the charging relay 231, which is controlled by charging control device 232, while the charging relay 231 charges the connected battery 13 in the form of different types of batteries, when the battery 13 serves as an intermediate circuit for supplying energy to the inverter 15 and further to the network 16. In the additional module 14, the energy is directed through the input measuring current element 142 and relay 141 of the UPS, and then continues to flow into the inverter 15, the relay being controlled by the control unit 143 of the UPS. The additional module 14 provides the possibility of charging the battery 13 when using the DC-to-DC converter 4, while taking advantage of the use of the photovoltaic unit 1 at the point of maximum power. The next function of the additional module 14 is the monitoring of the current that passes through one phase and the switching of the inverter 15 in case of exceeding the specified load for switching, and at the same time, the elimination of losses in the load in the inverter 15 is achieved. The inverter 15 in this case is implemented using a UPS type with double transformation. Thus, the system makes it possible to maintain one phase with a UPS and control the flow of energy when the power source of all system components is duplicated. All control of the system is carried out using the control unit 8, which transmits and evaluates information from the DC-to-DC converter 4, from the energy consumption control unit 2, from the additional module 14 and from the sensor 17 of the intelligent remote control.

Industrial applicability

This invention is intended to be integrated into photovoltaic systems in order to obtain an economical use of energy sources with the efficient use of energy obtained from photovoltaic cells, as well as to enable the use of cheap energy from the distribution network, while the energy supplied to the system can be used to heat water or charging batteries.

Claims (1)

FORMULA OF THE INVENTION 25 1. A system for controlling electrical energy produced by means of photovoltaic cells, which includes an interconnected unit (2) for controlling energy consumption, a unit (8) for controlling and a heating unit (9) equipped with a unit (91) for measuring temperature, and at least one heating element (92) modified for heating a liquid, characterized in that the energy consumption control unit (2) includes a control unit (21) From DC and AC control unit (22) and partially connected to AC power source (10), either directly or through an auxiliary AC voltage source (12), and partially connected to photovoltaic unit (1) made with the ability to create a direct current essentially through the main source (b) of the direct current voltage or through a serially connected output unit (5) measuring current and voltage, a converter (4) 35 direct current into the constant and input unit (3) measuring current and voltage, while the control unit (8) is also connected through a galvanically isolated auxiliary voltage source (7) of direct current to the photoelectric unit (1), and galvanically de connected main AC voltage source (11) with AC power source (10), while DC control unit (21) of unit (2) 40 energy consumption management is made with the ability to operate in the constant voltage mode, consists of a DC fuse (211) and a DC relay (212), which is connected to a DC thermostat (213), while the DC fuse (211) of current is connected through the output unit (5) of the measurement with the converter (4) of direct current to direct current, and the unit (22) of the control of the alternating current of the unit (2) of the control 45 energy consumption, made with the ability to operate in the AC mode, consists of an AC fuse (221) and an AC relay (222) connected to an AC thermostat (223), while an AC fuse (221) is connected to the AC power source (10), and the DC relay (212) and the AC relay (222) are interconnected to the heating unit (9). 50 2. The system according to claim 1, characterized in that the DC fuse (211) and the AC fuse (212) of the power consumption control unit (2) are interconnected through a control protection element (100) with which the temperature measuring unit (101), fuse (102), DC power relay (103) and AC power relay (104) are connected. 55 3. The system according to claim 1, characterized in that the DC-to-DC converter (4) is partially connected to the main DC voltage source (6), partially to the control unit (8), and partially includes interconnected the main switch (41) and the auxiliary switch (42), and near the auxiliary switch (42) a parallel circuit with an integrated inductive element (43) is made, to which the capacitor (44) and the load (45) are connected in parallel. 4. The system according to claim 1, characterized in that the power consumption control unit (2) is equipped with a charging unit (23), which is partially made of a charging relay (231) and a charging control device (232) and is partially connected to at least one energy accumulator (13). 5. The system according to claim 4, which is characterized by the fact that the energy accumulator (13) is interconnected with the inverter (15), which is modified to supply energy to the network (16). 6. The system according to claim 1, which differs in that an additional module (14) consisting of a relay (141) of an uninterruptible power supply (UPS) is connected to the power consumption control unit (2), as well as to the control unit (8). and the current measurement input element (142) and the control unit (143) (UPS) are connected in parallel to it, while the measurement input element 142 is connected to the UPS (10) and the UPS relay (141) is interconnected with the inverter (15). 7. The system according to claim 6, which differs in that the inverter (15) is implemented as a double-conversion UPS-type unit. 8. The system according to claim 1, which is characterized by the fact that the control unit (8) is equipped with a detector (17) of intelligent remote control to detect off-peak current and/or a communication module (18) to ensure communication with the main system. 9. The system according to claim 1, which is characterized by the fact that the control unit (8) is equipped with a data carrier (19) for recording the order of operation of the system. ny SHE : і o veshi Taya p PE і cha ЧО Ні жі : p LY va : Her » Fig. 1 aty voshi she writes tires M KY -y py nn TOV o rent I I "B x: ENN E Bunt y KIEV te p sy Stevena nene vusnyn a TO Mt G zv rt Prav c) 032 c) Fig. 2 nd M i NN nn En x x NO i v i N What and with i and p x i her Shk vyni ni I Fig. Z scha Iv X x nyny s SHON u shi i ns i on - 100: - 408, V dn nok shin niny mn shchenya shi shin i s. PI NN AKA Fig. 4