阅读说明：本技术 一种组串级集热系统及其控制方法 (Cascade heat collection system and control method thereof ) 是由 胡华友 于 2019-09-11 设计创作，主要内容包括：本发明公开了一种组串级集热系统,包括集热器、直流汇流箱、逆变器和控制终端；集热器包括用于连接光伏组件的输入接头,输入接头与集热器的加热元件连接；集热器与直流汇流箱连接,直流汇流箱与逆变器连接,控制终端分别与集热器和逆变器通讯连接；控制终端用于获取逆变器的功率；当逆变器的功率不小于第一额定功率时,控制终端控制集热器将光伏组件输出电流中超过第一额定电流的多余电流传输至加热元件。在超配状态下,控制终端可以在直流侧将多余电流传输至加热元件加热水流进行储存,从而避免电能的浪费以及可以避免逆变器过热出现降额运行情况的发生,从而保证逆变器传输的电量。本发明还提供了一种控制方法,同样具有上述有益效果。(the invention discloses a cascade heat collection system, which comprises a heat collector, a direct current combiner box, an inverter and a control terminal, wherein the direct current combiner box is arranged on the heat collector; the heat collector comprises an input connector used for connecting the photovoltaic module, and the input connector is connected with a heating element of the heat collector; the heat collector is connected with the direct current combiner box, the direct current combiner box is connected with the inverter, and the control terminal is respectively in communication connection with the heat collector and the inverter; the control terminal is used for obtaining the power of the inverter; when the power of the inverter is not less than the first rated power, the control terminal controls the heat collector to transmit surplus current exceeding the first rated current in the output current of the photovoltaic module to the heating element. Under the super-distribution state, the control terminal can transmit redundant current to the heating element at the direct current side to heat the water flow for storage, so that the waste of electric energy is avoided, the occurrence of derating operation condition caused by overheating of the inverter can be avoided, and the electric quantity transmitted by the inverter is ensured. The invention also provides a control method, which also has the beneficial effects.)

1. A cascade heat collection system is characterized by comprising a heat collector, a direct current combiner box, an inverter and a control terminal;

The heat collector comprises an input connector used for connecting a photovoltaic module, and the input connector is connected with a heating element of the heat collector; the heat collector is connected with the direct current combiner box, the direct current combiner box is connected with the inverter, and the control terminal is respectively in communication connection with the heat collector and the inverter;

the control terminal is used for acquiring the power of the inverter; when the power of the inverter is not less than the first rated power, the control terminal controls the heat collector to transmit surplus current exceeding the first rated current in the output current of the photovoltaic module to the heating element.

2. the cluster-grade heat collecting system of claim 1, wherein the control terminal is specifically configured to:

When the current running power of the inverter is detected to reach a maximum power inflection point, controlling the heat collector to transmit surplus current exceeding standard current in the output current of the photovoltaic module to the heating element; the standard current is the current corresponding to the maximum power of the inverter in the current output by the photovoltaic assembly.

3. The cluster-grade heat collecting system of claim 1, wherein a temperature sensor is arranged in the heat collector, and the control terminal is in communication connection with the temperature sensor;

The control terminal is specifically configured to:

Acquiring the temperature of water flow in the heat collector through the temperature sensor;

when the temperature of water flow in the heat collector is smaller than a first temperature threshold value and the power of the inverter is not smaller than a first rated power, the heat collector is controlled to transmit surplus current exceeding the first rated current in the output current of the photovoltaic module to the heating element.

4. the cluster cascade heat collection system of claim 3, wherein the control terminal is further configured to:

And when the temperature of the water flow in the heat collector is greater than a second temperature threshold value, disconnecting the heating element from the photovoltaic module.

5. The cluster-cascade heat collecting system of claim 4, wherein a low liquid level sensor and a high liquid level sensor are arranged in the heat collector, and both the low liquid level sensor and the high liquid level sensor are in communication connection with the control terminal;

the control terminal is specifically configured to:

acquiring the liquid level height of water flow in the heat collector through the low liquid level sensor and the high liquid level sensor;

when the liquid level of the water flow in the heat collector is lower than a first preset height, controlling a water inlet of the heat collector to be opened so as to inject the water flow;

And when the liquid level height of the water flow in the heat collector is higher than a second preset height, controlling the water inlet of the heat collector to be closed to stop the water flow injection.

6. The cluster-level heat collecting system of claim 1, wherein the control terminal comprises a measurement and control module of the dc combiner box.

7. A control method of a group cascade heat collection system is applied to a control terminal and is characterized by comprising the following steps:

acquiring the power of an inverter; the group of cascade heat collecting systems comprise a heat collector, a direct current combiner box, the inverter and a control terminal; the heat collector comprises an input connector used for connecting a photovoltaic module, and the input connector is connected with a heating element of the heat collector; the heat collector is connected with the direct current combiner box, the direct current combiner box is connected with the inverter, and the control terminal is respectively in communication connection with the heat collector and the inverter;

when the power of the inverter is not less than the first rated power, the heat collector is controlled to transmit the surplus current exceeding the first rated current in the output current of the photovoltaic module to the heating element.

8. the method of claim 7, wherein controlling the heat collector to deliver excess current in the photovoltaic module output current exceeding the first rated current to the heating element when the power of the inverter is not less than the first rated power comprises:

When the current running power of the inverter is detected to reach a maximum power inflection point, controlling the heat collector to transmit surplus current exceeding standard current in the output current of the photovoltaic module to the heating element; the standard current is the current corresponding to the maximum power of the inverter in the current output by the photovoltaic assembly.

9. The method of claim 7, further comprising:

acquiring the temperature of water flow in the heat collector through a temperature sensor; the temperature sensor is positioned in the heat collector;

The controlling the heat collector to transfer the surplus current exceeding the first rated current in the output current of the photovoltaic module to the heating element when the power of the inverter is not less than the first rated power comprises:

When the temperature of water flow in the heat collector is smaller than a first temperature threshold value and the power of the inverter is not smaller than a first rated power, the heat collector is controlled to transmit surplus current exceeding the first rated current in the output current of the photovoltaic module to the heating element.

10. The method of claim 9, wherein after said obtaining the temperature of the water flow within said collector via a temperature sensor, said method further comprises:

And when the temperature of the water flow in the heat collector is greater than a second temperature threshold value, disconnecting the heating element from the photovoltaic module.

Technical Field

The invention relates to the technical field of photovoltaics, in particular to a cascade heat collection system and a control method of the cascade heat collection system.

Background

at present, with subsidization of policies of a photovoltaic power generation system, the photovoltaic power generation system is required to be optimally designed from various angles, and the system cost is reduced. The direct current side over-distribution is a commonly adopted mode, but the over-distribution can cause partial loss of electric quantity generated by the photovoltaic module, and can cause the occurrence of peak clipping and even high-power derating operation of the inverter under the condition of ideal radiation value, and the loss of the generated energy is equivalent.

Therefore, how to ensure the electric quantity transmitted by the inverter in the over-distribution state and reduce the light abandonment is an urgent problem to be solved by the technical personnel in the field.

Disclosure of Invention

The invention aims to provide a cascade heat collecting system which can ensure the electric quantity transmitted by an inverter in an over-distribution state; the invention also provides a control method of the cascade heat collection system, which can ensure the electric quantity transmitted by the inverter in an over-distribution state.

In order to solve the technical problem, the invention provides a cascade heat collection system, which comprises a heat collector, a direct current combiner box, an inverter and a control terminal;

The heat collector comprises an input connector used for connecting a photovoltaic module, and the input connector is connected with a heating element of the heat collector; the heat collector is connected with the direct current combiner box, the direct current combiner box is connected with the inverter, and the control terminal is respectively in communication connection with the heat collector and the inverter;

the control terminal is used for acquiring the power of the inverter; when the power of the inverter is not less than the first rated power, the control terminal controls the heat collector to transmit surplus current exceeding the first rated current in the output current of the photovoltaic module to the heating element.

Optionally, the control terminal is specifically configured to:

When the current running power of the inverter is detected to reach a maximum power inflection point, controlling the heat collector to transmit surplus current exceeding standard current in the output current of the photovoltaic module to the heating element; the standard current is the current corresponding to the maximum power of the inverter in the current output by the photovoltaic assembly.

optionally, a temperature sensor is arranged in the heat collector, and the control terminal is in communication connection with the temperature sensor;

The control terminal is specifically configured to:

Acquiring the temperature of water flow in the heat collector through the temperature sensor;

when the temperature of water flow in the heat collector is smaller than a first temperature threshold value and the power of the inverter is not smaller than a first rated power, the heat collector is controlled to transmit surplus current exceeding the first rated current in the output current of the photovoltaic module to the heating element.

Optionally, the control terminal is further configured to:

And when the temperature of the water flow in the heat collector is greater than a second temperature threshold value, disconnecting the heating element from the photovoltaic module.

Optionally, a low liquid level sensor and a high liquid level sensor are arranged in the heat collector, and both the low liquid level sensor and the high liquid level sensor are in communication connection with the control terminal;

The control terminal is specifically configured to:

Acquiring the liquid level height of water flow in the heat collector through the low liquid level sensor and the high liquid level sensor;

when the liquid level of the water flow in the heat collector is lower than a first preset height, controlling a water inlet of the heat collector to be opened so as to inject the water flow;

And when the liquid level height of the water flow in the heat collector is higher than a second preset height, controlling the water inlet of the heat collector to be closed to stop the water flow injection.

Optionally, the control terminal includes a measurement and control module of the dc combiner box.

the invention also provides a control method of the cascade heat collection system, which is applied to a control terminal and comprises the following steps:

Acquiring the power of an inverter; the group of cascade heat collecting systems comprise a heat collector, a direct current combiner box, the inverter and a control terminal; the heat collector comprises an input connector used for connecting a photovoltaic module, and the input connector is connected with a heating element of the heat collector; the heat collector is connected with the direct current combiner box, the direct current combiner box is connected with the inverter, and the control terminal is respectively in communication connection with the heat collector and the inverter;

When the power of the inverter is not less than the first rated power, the heat collector is controlled to transmit the surplus current exceeding the first rated current in the output current of the photovoltaic module to the heating element.

Optionally, the controlling the heat collector to transfer the excess current exceeding the first rated current in the output current of the photovoltaic module to the heating element when the power of the inverter is not less than the first rated power includes:

when the current running power of the inverter is detected to reach a maximum power inflection point, controlling the heat collector to transmit surplus current exceeding standard current in the output current of the photovoltaic module to the heating element; the standard current is the current corresponding to the maximum power of the inverter in the current output by the photovoltaic assembly.

Optionally, the method further includes:

Acquiring the temperature of water flow in the heat collector through a temperature sensor; the temperature sensor is positioned in the heat collector;

the controlling the heat collector to transfer the surplus current exceeding the first rated current in the output current of the photovoltaic module to the heating element when the power of the inverter is not less than the first rated power comprises:

when the temperature of water flow in the heat collector is smaller than a first temperature threshold value and the power of the inverter is not smaller than a first rated power, the heat collector is controlled to transmit surplus current exceeding the first rated current in the output current of the photovoltaic module to the heating element.

Optionally, after the temperature of the water flow in the heat collector is obtained through the temperature sensor, the method further comprises the following steps:

And when the temperature of the water flow in the heat collector is greater than a second temperature threshold value, disconnecting the heating element from the photovoltaic module.

The invention provides a cascade heat collection system, which comprises a heat collector, a direct current combiner box, an inverter and a control terminal, wherein the direct current combiner box is arranged on the heat collector; the heat collector comprises an input connector used for connecting the photovoltaic module, and the input connector is connected with a heating element of the heat collector; the heat collector is connected with the direct current combiner box, the direct current combiner box is connected with the inverter, and the control terminal is respectively in communication connection with the heat collector and the inverter; the control terminal is used for obtaining the power of the inverter; when the power of the inverter is not less than the first rated power, the control terminal controls the heat collector to transmit surplus current exceeding the first rated current in the output current of the photovoltaic module to the heating element. Under the super-distribution state, the control terminal can transmit redundant current to the heating element at the direct current side to heat the water flow for storage, thereby avoiding the waste of electric energy and avoiding the occurrence of derating operation condition caused by the overheating of the inverter, ensuring the electric quantity transmitted by the inverter and simultaneously reducing the occurrence of light abandoning condition.

the invention also provides a control method of the cascade heat collection system, which has the beneficial effects and is not repeated herein.

drawings

In order to more clearly illustrate the embodiments or technical solutions of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained based on these drawings without creative efforts.

Fig. 1 is a block diagram of a cascade heat collecting system according to an embodiment of the present invention;

FIG. 2 is a schematic view of the construction of the collector during use;

FIG. 3 is a schematic structural diagram of a heat collector in a specific cluster-level heat collecting system according to an embodiment of the present invention;

Fig. 4 is a flowchart of a control method for a cascade heat collecting system according to an embodiment of the present invention;

Fig. 5 is a flowchart of a specific method for controlling a cluster-level heat collecting system according to an embodiment of the present invention.

In the figure: 1. the system comprises a heat collector, 11 input connectors, 12 heating elements, 13 heat collecting water tanks, 14 water inlets, 15 water outlets, 16 temperature sensors, 17 low liquid level sensors, 18 high liquid level sensors, 2 direct current combiner boxes, 3 inverters and 4 control terminals.

Detailed Description

The core of the invention is to provide a cascade heat collecting system. In the prior art, when the direct current side in the photovoltaic power generation system is over-matched, although the inverter can be ensured to operate in a full-power state, partial current generated by the photovoltaic module is wasted; meanwhile, the over-matching can cause the inverter to overheat due to overlarge current, and further cause the occurrence of derating operation conditions.

The invention provides a cascade heat collecting system, which comprises a heat collector, a direct current combiner box, an inverter and a control terminal; the heat collector comprises an input connector used for connecting the photovoltaic module, and the input connector is connected with a heating element of the heat collector; the heat collector is connected with the direct current combiner box, the direct current combiner box is connected with the inverter, and the control terminal is respectively in communication connection with the heat collector and the inverter; the control terminal is used for obtaining the power of the inverter; when the power of the inverter is not less than the first rated power, the control terminal controls the heat collector to transmit surplus current exceeding the first rated current in the output current of the photovoltaic module to the heating element. Under the super-distribution state, the control terminal can transmit redundant current to the heating element at the direct current side to heat the water flow for storage, thereby avoiding the waste of electric energy and avoiding the occurrence of derating operation condition caused by the overheating of the inverter, ensuring the electric quantity transmitted by the inverter and simultaneously reducing the occurrence of light abandoning condition.

In order that those skilled in the art will better understand the disclosure, the invention will be described in further detail with reference to the accompanying drawings and specific embodiments. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1 and fig. 2, fig. 1 is a block diagram of a cascade heat collecting system according to an embodiment of the present invention; fig. 2 is a schematic structural view of the heat collector in use.

referring to fig. 1 and 2, in the embodiment of the present invention, the cluster-level heat collecting system includes a heat collector 1, a dc combiner box 2, an inverter 3, and a control terminal 4; the heat collector 1 comprises an input connector 11 for connecting a photovoltaic module, and the input connector 11 is connected with a heating element 12 of the heat collector 1; the heat collector 1 is connected with the direct current combiner box 2, the direct current combiner box 2 is connected with the inverter 3, and the control terminal 4 is respectively in communication connection with the heat collector 1 and the inverter 3; the control terminal 4 is used for obtaining the power of the inverter 3; when the power of the inverter 3 is not less than the first rated power, the control terminal 4 controls the heat collector 1 to transmit the surplus current exceeding the first rated current in the output current of the photovoltaic module to the heating element 12.

In the embodiment of the present invention, the heat collector 1 includes an input connector 11 for connecting the photovoltaic module and a heating element 12, and the input connector 11 is connected with the heating element 12. In general, the heat collector 1 further comprises a heat collecting water tank 13 for containing water, the heat collecting water tank 13 comprises a water inlet and a water outlet 15, and the heating element 12 is located in the heat collecting water tank 13 for heating water.

Since the input connector 11 for connecting the photovoltaic module is connected to the heating element 12, and the heat collector 1 is connected to the dc combiner box 2, that is, in the using process, the heat collector 1 provided in the embodiment of the present invention is connected to the photovoltaic module, the photovoltaic module is specifically connected to the dc combiner box 2 through the heat collector 1, and the circuit generated by the photovoltaic module is transmitted to the dc combiner box 2 through the heat collector 1, and is usually collected into the dc bus of the dc combiner box 2.

the dc combiner box 2 is connected to the inverter 3, the inverter 3 is usually connected to a dc bus of the dc combiner box 2, and the dc generated by the photovoltaic module enters the inverter 3 through the dc combiner box 2, so as to convert the dc into ac. Generally, the cluster-level heat collection system provided by the embodiment of the invention further includes an ac power distribution cabinet, the ac power distribution cabinet is connected to the inverter 3, and the ac power converted by the inverter 3 can be transmitted to a power grid through a current power distribution cabinet. For the specific structures of the inverter 3, the ac distribution cabinet and the dc combiner box 2, reference may be made to the prior art, and detailed descriptions thereof are omitted.

The control terminal 4 needs to be in communication connection with the heat collector 1 and the inverter 3 respectively so as to obtain the power of the inverter 3 and control the heat collector 1. In particular, the control terminal 4 is required for obtaining the power of the inverter 3, typically the current power of the inverter 3. When the power of the inverter 3 is not less than the first rated power, that is, when the power of the inverter 3 is larger, usually the power of the inverter 3 reaches the maximum power, that is, the inverter 3 runs at full power, the control terminal 4 needs to control the heat collector 1 to transmit the excess current exceeding the first rated current in the output current of the photovoltaic module to the heating element 12.

The first rated current, that is, the power of the inverter 3, corresponds to the magnitude of the output current of the photovoltaic module when the photovoltaic module operates at the first rated power. Normally, the first rated current corresponds to the magnitude of the current in the dc combiner box 2 when the inverter 3 is operating at full power. Specifically, the excess current exceeding the first rated current in the current generated by the photovoltaic module is usually wasted in the overload state of the inverter 3, and cannot be converted into the current of the alternating current by the inverter 3. In the embodiment of the invention, when the power of the inverter 3 is not less than the first rated power, the control terminal 4 may control the heat collector 1 to transmit the excess current exceeding the first rated current in the output current of the photovoltaic module to the heating element 12, so as to heat the water in the heat collector 1 by the excess current.

It should be noted that, in the embodiment of the present invention, the direct current generated by the photovoltaic module is not transmitted to the direct current combiner box 2 through the heating element 12 in the heat collector 1, but the heat collector 1 can introduce a part of the current output by the photovoltaic module into the heating element 12 to heat the water in the heat collector 1, that is, the heat collector 1 can control the current flowing into the heating element 12. Specifically, in the embodiment of the present invention, the control terminal 4 can control the heat collector 1 to transmit the redundant current in the output current of the photovoltaic module to the heating element 12.

specifically, in the embodiment of the present invention, the heat collector 1 generally includes a plurality of heating elements 12, and the heat collector 1 also generally includes a plurality of input connectors 11, wherein the input connectors 11 are connected to the heating elements 12 in a one-to-one correspondence. Each input connector 11 is connected to a group of photovoltaic modules during use, one heating element 12 for each group of photovoltaic modules.

In the embodiment of the present invention, in order to ensure that the control terminal 4 can accurately guide the redundant current in the output current of the photovoltaic module to the heating element 12, the control terminal 4 may be specifically configured to:

When detecting that the current operating power of the inverter 3 reaches a maximum power inflection point, controlling the heat collector 1 to transmit surplus current exceeding standard current in the output current of the photovoltaic module to the heating element 12; the standard current is a current corresponding to the maximum power of the inverter 3 in the current output by the photovoltaic module.

when the current operating power of the inverter 3 reaches the maximum power inflection point, which means that the power of the inverter 3 has reached the maximum at this time, the inverter 3 is in an over-distribution state, and there is an excess current in the current generated by the photovoltaic module. The control terminal 4 can control the heat collector 1 to transmit the excessive current exceeding the standard current to the heating element 12 to supply power to the heating element 12. Since the standard current is a current corresponding to the maximum power of the inverter 3 among the currents output by the photovoltaic module, the redundant current is a current that cannot be converted by the inverter 3.

The embodiment of the invention provides a cascade heat collection system, which comprises a heat collector 1, a direct current combiner box 2, an inverter 3 and a control terminal 4; the heat collector 1 comprises an input connector 11 for connecting a photovoltaic module, and the input connector 11 is connected with a heating element 12 of the heat collector 1; the heat collector 1 is connected with the direct current combiner box 2, the direct current combiner box 2 is connected with the inverter 3, and the control terminal 4 is respectively in communication connection with the heat collector 1 and the inverter 3; the control terminal 4 is used for obtaining the power of the inverter 3; when the power of the inverter 3 is not less than the first rated power, the control terminal 4 controls the heat collector 1 to transmit the surplus current exceeding the first rated current in the output current of the photovoltaic module to the heating element 12. Under the super-distribution state, the control terminal 4 can transmit the redundant current to the heating element 12 at the direct current side to heat the water flow for storage, thereby avoiding the waste of electric energy and avoiding the occurrence of derating operation condition caused by the overheating of the inverter 3, ensuring the electric quantity transmitted by the inverter 3 and simultaneously reducing the occurrence of light abandoning condition.

The specific structure of the cascade heat collecting system provided by the present invention will be described in detail in the following embodiments of the present invention.

referring to fig. 3, fig. 3 is a schematic structural diagram of a heat collector in a specific cluster-level heat collecting system according to an embodiment of the present invention.

Different from the above embodiment of the invention, the embodiment of the invention is further to specifically limit the structure of the cascade-stage heat collecting system on the basis of the above embodiment of the invention. The rest of the contents are already described in detail in the above embodiments of the present invention, and are not described herein again.

Referring to fig. 3, in the embodiment of the present invention, a temperature sensor 16 is disposed in the heat collector 1, and the control terminal 4 is in communication connection with the temperature sensor 16; the control terminal 4 is specifically configured to: acquiring the temperature of water flow in the heat collector 1 through the temperature sensor 16; when the temperature of the water flow in the heat collector 1 is less than a first temperature threshold value and the power of the inverter 3 is not less than a first rated power, the heat collector 1 is controlled to transmit the redundant current exceeding the first rated current in the output current of the photovoltaic module to the heating element 12.

in the embodiment of the present invention, a temperature sensor 16 may be disposed in the heat collector 1, and the temperature sensor 16 is generally located in the heat collecting water tank 13, and is configured to acquire the temperature of the water flow in the heat collector 1 and transmit the temperature parameter to the control terminal 4, that is, in the present invention, the control terminal 4 is configured to acquire the temperature of the water flow in the heat collector 1 through the temperature sensor 16.

The control terminal 4 is specifically configured to control the heat collector 1 to transmit the excess current exceeding the first rated current in the output current of the photovoltaic module to the heating element 12 when the temperature of the water flow in the heat collector 1 is less than the first temperature threshold and the power of the inverter 3 is not less than the first rated power. The details of the first rated power and the excess current are described in detail in the above embodiments of the invention, and will not be described herein. In the embodiment of the present invention, when the condition for transmitting the excess current to the heating element 12 needs to satisfy that the power of the inverter 3 is not less than the first rated power and the temperature of the water flow in the heat collector 1 is less than the first temperature threshold, that is, the temperature of the water flow in the heat collector 1 is low, the excess current is introduced to the heating element 12 to heat the water flow in the heat collector 1, so as to prevent the waste of electric energy and the over-high temperature of the water flow in the heat collector 1.

It should be noted that, in the embodiment of the present invention, the heat collector 1 can also control the heating power of the heating element 12 to be flexibly set according to the temperature requirement of the water flow in the heat collector 1. For example, when a user needs to increase the temperature of water in the heat collector 1 by 20 ℃, the heat collector 1 can rapidly heat the water by inputting a large current to the heating element 12 to enable the heating element 12 to generate a large heating power; when a user needs to increase the temperature of water in the heat collector by 2 ℃, the heat collector 1 can accurately heat the water by inputting a small current to the heating element 12 so that the heating element 12 generates a small heating power.

Specifically, in the embodiment of the present invention, the control terminal 4 may be further configured to disconnect the heating element 12 from the photovoltaic module when the temperature of the water flow in the heat collector 1 is greater than a second temperature threshold. When the temperature of rivers is greater than the second temperature threshold value in heat collector 1, when the temperature of rivers is higher in heat collector 1 promptly, disconnection heating element 12 and photovoltaic module's connection, the production of photovoltaic module can not have this moment and the electric current supply to heating element 12 more to can avoid the rivers high temperature in heat collector 1.

Further, in the embodiment of the present invention, the heat collector 1 can also control the on/off between the heating element 12 and the photovoltaic module according to the water demand of the user. In particular, the connection of the heating element 12 to the photovoltaic module can be disconnected, for example when the user has no need for water, regardless of the temperature of the water in the collector 1.

In the embodiment of the invention, the heat collector 1 can be further provided with a low liquid level sensor 17 and a high liquid level sensor 18, and both the low liquid level sensor 17 and the high liquid level sensor 18 are in communication connection with the control terminal 4; the control terminal 4 is specifically configured to obtain a liquid level height of water flow in the heat collector 1 through the low liquid level sensor 17 and the high liquid level sensor 18; when the liquid level of the water flow in the heat collector 1 is lower than a first preset height, controlling the water inlet 14 of the heat collector 1 to be opened so as to inject the water flow; when the liquid level height of the water flow in the heat collector 1 is higher than a second preset height, controlling the water inlet 14 of the heat collector 1 to be closed to stop the water flow injection.

the low liquid level sensor 17 and the high liquid level sensor 18 are usually located in the heat collecting water tank 13 and are used for acquiring the height of water flow in the heat collector 1, wherein the low liquid level sensor 17 can send a signal when the water flow in the heat collector 1 is too low, and the high liquid level sensor 18 can send a signal when the water flow in the heat collector 1 is too high; the height of the water flow in the heat collector 1 can be detected through the low liquid level sensor 17 and the high liquid level sensor 18, the height parameters of the liquid level in the heat collector 1 can be transmitted to the control terminal 4 through the low liquid level sensor 17 and the high liquid level sensor 18, and the control terminal 4 is used for acquiring the liquid level height of the water flow in the heat collector 1 through the low liquid level sensor 17 and the high liquid level sensor 18 in real time.

The control terminal 4 is specifically configured to control the water inlet 14 of the heat collector 1 to be opened to inject water into the heat collecting water tank 13 when the liquid level of the water in the heat collector 1 is lower than a first preset height, that is, when the low liquid level sensor 17 sends a signal; when the liquid level height of the water flow in the heat collector 1 is higher than a second preset height, namely a signal is sent by the high liquid level sensor 18, the water inlet 14 of the heat collector 1 is controlled to be closed to stop the water flow injection, so that the liquid level height in the heat collector 1 is kept stable.

In an embodiment of the present invention, the control terminal 4 may include a measurement and control module of the dc combiner box 2. Of course, in the embodiment of the present invention, the control terminal 4 may further include other control modules, for example, an external controller or a control background. In the embodiment of the present invention, the control terminal 4 generally detects the power of the inverter 3 through the measurement and control module of the dc combiner box 2, that is, obtains the power of the inverter 3.

According to the cascade heat collection system provided by the embodiment of the invention, the temperature of the water flow in the heat collector 1 can be obtained through the temperature sensor 16, and the temperature of the water flow in the heat collector 1 is heated when the temperature of the water flow in the heat collector 1 is lower; the liquid level in the collector 1 can be kept stable by the low liquid level sensor 17 and the high liquid level sensor 18.

In the following, a control method of a group cascade heat collecting system provided by an embodiment of the present invention is introduced, and the control method described below and the group cascade heat collecting system described above may be referred to correspondingly.

Referring to fig. 4, fig. 4 is a flowchart of a method for controlling a cascade heat collecting system according to an embodiment of the present invention.

In the embodiment of the present invention, the control method is specifically applied to the control terminal 4, and the control terminal 4 controls the magnitude of the current in the dc combiner box 2 through the heat collector 1.

referring to fig. 4, in an embodiment of the present invention, the control method may include:

S101: and acquiring the power of the inverter.

In the embodiment of the invention, the cascade heat collection system comprises a heat collector 1, a direct current combiner box 2, the inverter 3 and a control terminal 4; the heat collector 1 comprises an input connector 11 for connecting a photovoltaic module, and the input connector 11 is connected with a heating element 12 of the heat collector 1; the heat collector 1 is connected with the direct current combiner box 2, the direct current combiner box 2 is connected with the inverter 3, and the control terminal 4 is respectively in communication connection with the heat collector 1 and the inverter 3. The specific structure of the group cascade stage heat collecting system has been described in detail in the above embodiments of the present invention, and will not be described herein again.

In this step, the control terminal 4 obtains the magnitude of the power value of the inverter 3, generally the current power of the inverter 3, so as to determine the state of the inverter 3.

s102: when the power of the inverter is not less than the first rated power, the heat collector is controlled to transmit the redundant current exceeding the first rated current in the output current of the photovoltaic module to the heating element.

In this step, when the power of the inverter 3 is not less than the first rated power, that is, when the power of the inverter 3 is large, it is general that the power of the inverter 3 reaches the maximum power, that is, the inverter 3 runs at full power. The first rated current, that is, the power of the inverter 3 corresponds to the magnitude of the output current of the photovoltaic module when the inverter operates at the first rated power. Normally, the first rated current corresponds to the magnitude of the current in the dc combiner box 2 when the inverter 3 is operating at full power. Specifically, the excess current exceeding the first rated current in the current generated by the photovoltaic module is usually wasted in the overload state of the inverter 3, and cannot be converted into the current of the alternating current by the inverter 3. In this step, when the power of the inverter 3 is not less than the first rated power, the heat collector 1 is controlled to transmit the excess current exceeding the first rated current in the output current of the photovoltaic module to the heating element 12, so as to heat the water in the heat collector 1 through the excess current, and further regulate and control the magnitude of the current flowing into the dc combiner box 2 by the photovoltaic module.

specifically, the step may specifically be:

When detecting that the current operating power of the inverter 3 reaches a maximum power inflection point, controlling the heat collector 1 to transmit surplus current exceeding standard current in the output current of the photovoltaic module to the heating element 12; the standard current is a current corresponding to the maximum power of the inverter 3 in the current output by the photovoltaic module. When the current operating power of the inverter 3 reaches the maximum power inflection point, which means that the power of the inverter 3 has reached the maximum at this time, the inverter 3 is in an over-distribution state, and there is an excess current in the current generated by the photovoltaic module. At this time, the control terminal 4 may control the heat collector 1 to transmit the surplus current exceeding the standard current to the heating element 12 to supply power to the heating element 12. Since the standard current is a current corresponding to the maximum power of the inverter 3 among the currents output by the photovoltaic module, the redundant current is a current that cannot be converted by the inverter 3.

In the control method of the cascade heat collection system provided by the embodiment of the invention, in the super-distribution state, the control terminal 4 can transmit the redundant current to the heating element 12 at the direct current side to heat the water flow for storage, so that the waste of electric energy is avoided, the occurrence of derating operation condition caused by overheating of the inverter 3 can be avoided, and the electric quantity transmitted by the inverter 3 is ensured.

the detailed contents of the control method for a cascade heat collecting system provided by the present invention will be described in detail in the following embodiments of the present invention.

Referring to fig. 5, fig. 5 is a flowchart illustrating a specific method for controlling a cluster-level heat collecting system according to an embodiment of the present invention.

Referring to fig. 5, in an embodiment of the present invention, the control method may include:

S201: and acquiring the power of the inverter.

this step is substantially the same as S101 in the above embodiment of the present invention, and for details, reference is made to the above embodiment of the present invention, which is not repeated herein.

S202: the temperature of the water flow in the heat collector is obtained through the temperature sensor.

in the present embodiment, the temperature sensor 16 is located in the heat collector 1. The detailed structure of the heat collector 1 has been described in the above embodiments of the invention, and will not be described herein.

in this step, the control terminal 4 obtains the temperature of the water flow in the heat collector 1, so as to judge the state of the temperature of the water flow in the heat collector 1. It should be noted that this step is usually executed in parallel with S201, that is, there is no sequence between S201 and S202.

s203: when the temperature of water flow in the heat collector is smaller than a first temperature threshold value and the power of the inverter is not smaller than a first rated power, the heat collector is controlled to transmit redundant current exceeding the first rated current in the output current of the photovoltaic module to the heating element.

this step is substantially similar to the step S102 in the above-mentioned embodiment of the invention, and in this step, before the current is transmitted to the heating element 12, in addition to the requirement that the power of the inverter 3 is not less than the first rated power, the temperature of the water flow in the heat collector 1 is less than the first temperature threshold, that is, when the temperature of the water flow in the heat collector 1 is low, the excessive current is introduced into the heating element 12 to heat the water flow in the heat collector 1, so as to prevent the waste of electric energy and the over-high temperature of the water flow in the heat collector 1. The rest of the steps have been described in detail in the above embodiments of the present invention, and are not described herein again.

S204: and when the temperature of the water flow in the heat collector is greater than a second temperature threshold value, disconnecting the heating element from the photovoltaic module.

In this step, when the temperature of the water flow in the heat collector 1 is greater than the second temperature threshold, that is, the temperature of the water flow in the heat collector 1 is high, the connection between the heating element 12 and the photovoltaic module needs to be disconnected, and at this time, the power supply to the heating element 12 by the much current generated by the photovoltaic module is avoided, so that the overhigh temperature of the water flow in the heat collector 1 can be avoided.

The control method of the cascade-connected heat collection system provided by the embodiment of the invention can heat water by using redundant current generated by the photovoltaic module when the temperature of water flow in the heat collector 1 is low, and can be closed when the temperature is high, so that the waste of electric energy can be prevented, and the temperature of the water flow in the heat collector 1 can be prevented.

The embodiments are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same or similar parts among the embodiments are referred to each other.

those of skill would further appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that the various illustrative components and steps have been described above generally in terms of their functionality in order to clearly illustrate this interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in Random Access Memory (RAM), memory, Read Only Memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

Finally, it should also be noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The present invention provides a cascade heat collecting system and a control method thereof. The principles and embodiments of the present invention are explained herein using specific examples, which are presented only to assist in understanding the method and its core concepts. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.