CN115395571A

CN115395571A - Method, device and system for controlling power generation efficiency of photovoltaic power generation system and medium

Info

Publication number: CN115395571A
Application number: CN202211155493.7A
Authority: CN
Inventors: 蔡昊; 陈鹏; 王凯杰; 孟鹏飞
Original assignee: Sungrow Power Supply Co Ltd
Current assignee: Sungrow Power Supply Co Ltd
Priority date: 2022-09-21
Filing date: 2022-09-21
Publication date: 2022-11-25

Abstract

The invention discloses a method, a device, a system and a medium for controlling the generating efficiency of a photovoltaic power generation system. According to the invention, the operation state of the transformer bank is controlled through the switching control device, so that the efficiency of the transformer bank can be kept at the optimal efficiency, and the generation efficiency of the photovoltaic power generation system is improved.

Description

Control method, device, system and medium for generating efficiency of photovoltaic power generation system

Technical Field

The invention relates to the technical field of photovoltaic power generation, in particular to a control method, a control device system and a computer readable storage medium for the power generation efficiency of a photovoltaic power generation system.

Background

The photovoltaic power generation system is composed of photovoltaic array groups, header box groups, inverter groups, transformer groups and other equipment, and is typical periodic and intermittent energy power generation equipment. The power generation efficiency of the photovoltaic power generation system is determined by solar energy resource characteristics and equipment characteristics of the photovoltaic power generation system, and the transformer bank is used as a key component in the photovoltaic power generation system and has a crucial influence on the power generation efficiency of the whole photovoltaic power generation system.

However, in the topology structure of the existing photovoltaic power generation system, the connection mode between the transformer bank and the inverter bank is that the transformer in the transformer bank and the inverter in the inverter bank are connected one-to-one, and in the operation process, when the load of the transformer bank exceeds a certain load value, the operation efficiency of the transformer bank starts to decrease, so that the power generation efficiency of the whole photovoltaic power generation system shows a decreasing trend, which is very unfavorable for the improvement of the power generation efficiency of the photovoltaic power generation system.

Disclosure of Invention

The invention mainly aims to provide a control method, a control device system and a computer readable storage medium for the power generation efficiency of a photovoltaic power generation system, and aims to improve the power generation efficiency of the photovoltaic power generation system by controlling the operation efficiency of a transformer bank.

In order to achieve the above object, the present invention provides a method for controlling the generating efficiency of a photovoltaic power generation system, which comprises the following steps:

acquiring cut-off power loss of the transformer bank in a cut-off state and acquiring input power loss of the transformer bank in an input state, wherein the input state is a state that an inverter in the inverter bank is correspondingly connected with a transformer in the transformer bank, the cut-off state is a state that at least one multi-connection transformer exists in the transformer bank, and the multi-connection transformer is a transformer which is simultaneously connected with at least two inverters in the inverter bank;

when the cut-off power loss is smaller than the input power loss, the switching control device controls the transformer bank to enter the cut-off state;

and when the cut-off power loss is detected to be larger than the input power loss, controlling the transformer bank to enter the input state through the switching control device.

Optionally, before the step of obtaining the cut-off power loss of the transformer bank in the cut-off state and obtaining the input power loss of the transformer bank in the input state, the method further includes:

acquiring a first predicted power curve of each inverter in the inverter group in a predicted time period;

superposing the first predicted power curves of the inverters connected to the same multi-connection transformer in the cut-off state to obtain a second predicted power curve of the inverter group;

detecting whether a target prediction curve with the power value of the second prediction power curve smaller than the rated capacity of the transformer bank exists or not;

and when detecting that the target prediction curve with the power value of the second prediction power curve smaller than the rated capacity of the transformer bank exists, executing the steps of acquiring the cut-off power loss of the transformer bank in the cut-off state and acquiring the input power loss of the transformer bank in the input state within a first target time period corresponding to the target prediction curve or at a first target moment.

Optionally, after the step of detecting whether there exists the target prediction curve of which the power value of the second prediction power curve is smaller than the rated capacity of the transformer bank, the method further includes:

and when detecting that the power value of the second predicted power curve in a second target time period or at a second target moment is greater than the rated capacity of the transformer bank, controlling the transformer bank to enter the switching state in the second target time period or at the second target moment through the switching control device.

Optionally, the step of acquiring a cut-off power loss of the transformer bank in a cut-off state includes:

calculating a predicted cut-off load rate of a first multi-connection transformer of the multi-connection transformers in the cut-off state according to the target prediction curve and rated parameters of the transformer bank, and calculating cut-off efficiency of the transformer bank based on the predicted cut-off load rate, wherein the first multi-connection transformer is a multi-connection transformer corresponding to the target prediction curve;

and calculating the cut-off power loss according to the second predicted power curve and the cut-off efficiency.

Optionally, when it is detected that the cut-off power loss is smaller than the input power loss, the step of controlling the transformer bank to enter the cut-off state by the switching control device includes:

when the cut-off power loss is detected to be smaller than the input power loss in a first power prediction time period or at a first power prediction time, the first multi-connection transformer in the transformer bank is controlled to enter the cut-off state in the first power prediction time period or at the first power prediction time through the switching control device.

Optionally, the step of obtaining the input power loss of the transformer bank in the input state includes:

obtaining the respective efficiency of each transformer in the transformer bank;

and calculating the input power loss according to the first predicted power curve and the efficiency.

Optionally, the step of obtaining the respective efficiency of each transformer in the transformer bank includes:

calculating a respective predicted load factor of each transformer based on the first predicted power curve and a rated parameter of the transformer corresponding to the inverter of the first predicted power curve;

and calculating the efficiency of each transformer based on the predicted load rate and the rated parameters of the transformer corresponding to the predicted load rate.

Optionally, when it is detected that the cut-off power loss is greater than the input power loss, the step of controlling, by the switching control device, the transformer bank to enter the input state includes:

and when the condition that the cut-off power loss is larger than the input power loss is detected in a second power prediction time period or at a second power prediction time, controlling the transformer bank to enter the input state in the second power prediction time period or at the second power prediction time through the switching control device.

Optionally, after the step of controlling the transformer bank to enter the cut-off state by the switching control device when it is detected that the cut-off power loss is smaller than the input power loss, the method further includes:

and calculating the non-loss electric quantity of the photovoltaic power generation system in the cut-off state according to the power loss difference between the input power loss and the cut-off power loss.

The invention also provides a control device of the generating efficiency of the photovoltaic power generation system, which comprises the following components:

the acquisition module is used for acquiring the cut-off power loss of the transformer bank in a cut-off state and acquiring the input power loss of the transformer bank in an input state, wherein the input state is a state that an inverter in the inverter bank is correspondingly connected with a transformer in the transformer bank, the cut-off state is a state that at least one multi-connection transformer exists in the transformer bank, and the multi-connection transformer is a transformer which is simultaneously connected with at least two inverters in the inverter bank;

the control module is used for controlling the transformer bank to enter the cut-off state through the switching control device when the cut-off power loss is detected to be smaller than the input power loss;

and the control module is also used for controlling the transformer bank to enter the input state through the switching control device when the switching-off power loss is detected to be larger than the input power loss.

In addition, in order to achieve the above object, the present invention provides a control device system for generating efficiency of a photovoltaic power generation system, the control device system for generating efficiency of a photovoltaic power generation system includes a controller and a photovoltaic power generation system, the photovoltaic power generation system includes an inverter group, a switching control device and a transformer group, and the controller is configured to implement the steps of the control method for generating efficiency of the photovoltaic power generation system when executing.

In addition, to achieve the above object, the present invention further provides a computer-readable storage medium having a control program stored thereon, where the control program, when executed by a processor, implements the steps of the method for controlling the power generation efficiency of the photovoltaic power generation system.

The invention provides a method, a device, a system and a medium for controlling the generating efficiency of a photovoltaic power generation system, wherein the method comprises the steps of obtaining the cut-off power loss of a transformer bank in a cut-off state and obtaining the input power loss of the transformer bank in an input state, and controlling the transformer bank to enter the cut-off state through a switching control device when the cut-off power loss is detected to be smaller than the input power loss; and when the cut-off power loss is detected to be larger than the input power loss, controlling the transformer bank to enter an input state through the switching control device. The invention detects the cut-off power loss of the transformer bank and the input power loss of the transformer bank, and controls the transformer bank to enter different running states through the switching control device according to the detection result, thereby controlling the running efficiency of the transformer bank and improving the generating efficiency of the photovoltaic generating system.

Drawings

Fig. 1 is a schematic terminal structure diagram of a hardware operating environment according to an embodiment of the present invention;

FIG. 2 is a schematic flow chart of a first embodiment of a method for controlling the generating efficiency of a photovoltaic power generation system according to the present invention;

fig. 3 is a schematic view of a topology of a photovoltaic power generation system according to an embodiment of the present invention;

FIG. 4 is a detailed flowchart of step S10 in the first embodiment of the present invention;

FIG. 5 is a detailed flowchart of step S10 in the first embodiment of the present invention;

FIG. 6 is a detailed flowchart of step S20 in the first embodiment of the present invention;

fig. 7 is a schematic view of the rated parameters of a transformer bank according to a first embodiment of the present invention;

fig. 8 is a schematic diagram of an efficiency-load ratio curve of a transformer bank according to a first embodiment of the present invention;

fig. 9 is a diagram illustrating a second predicted power curve of the inverter group after the first predicted power curves of N1 and N2 are superimposed according to the first embodiment of the present invention;

fig. 10 is a schematic control timing diagram of the switching control device according to the first embodiment of the present invention;

FIG. 11 is a schematic flowchart of a second embodiment of the method for controlling the generating efficiency of a photovoltaic power generation system according to the present invention;

fig. 12 is a block diagram schematically illustrating a control apparatus for controlling the power generation efficiency of the photovoltaic power generation system according to the present invention.

The reference numbers indicate:

reference numerals	Name (R)
		N1-N2	Inverter with a voltage regulator
B1-B2	Transformer device
		KA	Switching control device
S1-	Switch with a switch body
		Ska1-Ska2	Switching switch
10	Acquisition module
		20	Control module

The objects, features and advantages of the present invention will be further explained with reference to the accompanying drawings.

Detailed Description

It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not limit the invention.

The existing transformer bank runs in parallel with the inverter bank in the topological structure of the existing photovoltaic power generation system, and in the running process, when the load of the existing transformer bank exceeds a certain load value, the running efficiency of the transformer bank begins to decline, so that the power generation efficiency of the whole photovoltaic power generation system shows a decline trend, the improvement of the power generation efficiency of the photovoltaic power generation system is not facilitated, and the decline of the power generation efficiency of the photovoltaic power generation system can cause the decline of the safety, stability and economic operation of the photovoltaic power generation system.

As shown in fig. 1, fig. 1 is a schematic terminal structure diagram of a hardware operating environment according to an embodiment of the present invention.

The implementation terminal of the present invention is a control device system for the power generation efficiency of a photovoltaic power generation system, as shown in fig. 1, the control device system for the power generation efficiency of the photovoltaic power generation system may include: a processor 1001, e.g. a CPU, a network interface 1004, a user interface 1003, a memory 1005, a communication bus 1002. Wherein a communication bus 1002 is used to enable connective communication between these components. The user interface 1003 may include a Display screen (Display), an input unit such as a Keyboard (Keyboard), and the optional user interface 1003 may also include a standard wired interface, a wireless interface. The network interface 1004 may optionally include a standard wired interface, a wireless interface (e.g., WI-FI interface). The memory 1005 may be a high-speed RAM memory or a non-volatile memory (e.g., a magnetic disk memory). The memory 1005 may alternatively be a storage device separate from the processor 1001.

Optionally, the control device system for the power generation efficiency of the photovoltaic power generation system may further include an RF (Radio Frequency) circuit, a sensor, a WiFi module, and the like. Such as light sensors, motion sensors, and other sensors, will not be described in detail herein.

Those skilled in the art will appreciate that the control device system architecture for the power generation efficiency of a photovoltaic power generation system illustrated in fig. 1 does not constitute a limitation of the control device system for the power generation efficiency of a photovoltaic power generation system, and may include more or fewer components than those illustrated, or some components in combination, or a different arrangement of components.

As shown in fig. 1, the memory 1005, which is a kind of computer storage medium, may include therein an operating system, a network communication module, a user interface module, and a control program.

In the control device system for controlling the power generation efficiency of the photovoltaic power generation system shown in fig. 1, the network interface 1004 is mainly used for connecting a background server and performing data communication with the background server; the user interface 1003 is mainly used for connecting a client (user side) and performing data communication with the client; and the processor 1001 may be configured to call the control program stored in the memory 1005 and perform the following operations:

Further, the processor 1001 may call the control program stored in the memory 1005, and also perform the following operations:

before the step of obtaining the cut-off power loss of the transformer bank in the cut-off state and the step of obtaining the input power loss of the transformer bank in the input state, obtaining a first prediction power curve of each inverter in the inverter bank in a prediction time period;

when it is detected that there is the target prediction curve in which the power value of the second prediction power curve is smaller than the rated capacity of the transformer bank, the step of acquiring the cut-off power loss of the transformer bank in the cut-off state and the step of acquiring the input power loss of the transformer bank in the input state are executed within a first target time period or at the first target time corresponding to the target prediction curve.

after the step of detecting whether a target prediction curve with the power value of the second prediction power curve smaller than the rated capacity of the transformer bank exists or not, when the step of detecting whether the power value of the second prediction power curve in a second target time period or at a second target moment is larger than the rated capacity of the transformer bank or not is detected, the switching control device controls the transformer bank to enter the switching state in the second target time period or at the second target moment.

the step of acquiring the cut-off power loss of the transformer bank in the cut-off state includes: calculating a predicted cut-off load rate of a first multi-connection transformer in the multi-connection transformers in the cut-off state according to the target prediction curve and rated parameters of the transformer bank, and calculating cut-off efficiency of the transformer bank based on the predicted cut-off load rate, wherein the first multi-connection transformer is a multi-connection transformer corresponding to the target prediction curve;

calculating the cut-off power loss according to the second predicted power curve and the cut-off efficiency.

when the cut-off power loss is smaller than the input power loss, the step of controlling the transformer bank to enter the cut-off state through the switching control device comprises the following steps:

the step of obtaining the input power loss of the transformer bank in the input state comprises the following steps:

the step of obtaining the respective efficiency of each transformer in the transformer bank comprises:

calculating the respective predicted load rates of the transformers based on the first predicted power curve and the rated parameters of the transformers corresponding to the inverters of the first predicted power curve;

the step of controlling the transformer bank to enter the commissioning state by the switching control device when it is detected that the cut-off power loss is greater than the commissioning power loss includes: and when the cutoff power loss is detected to be larger than the input power loss in a second power prediction time period or at a second power prediction moment, controlling the transformer bank to enter the input state in the second power prediction time period or at the second power prediction moment through the switching control device.

after the step of controlling the transformer bank to enter the cut-off state by the switching control device when it is detected that the cut-off power loss is smaller than the input power loss, the method further includes:

Referring to fig. 2, in a first embodiment of the present invention, a method for controlling the power generation efficiency of a photovoltaic power generation system includes:

step S10, acquiring the cut-off power loss of the transformer bank in a cut-off state and acquiring the input power loss of the transformer bank in an input state, wherein the input state is a state that an inverter in the inverter bank is correspondingly connected with a transformer in the transformer bank, the cut-off state is a state that at least one multi-connection transformer exists in the transformer bank, and the multi-connection transformer is a transformer which is simultaneously connected with at least two inverters in the inverter bank;

in the embodiment of the invention, the connection mode between the inverter group and the transformer group is modified, for example, as shown in fig. 3, the inverter group in the photovoltaic power generation system and the inverter equipment and the transformer equipment in the transformer group are respectively two, topology of the output end of the inverter and the input end of the transformer is modified, that is, a switching control device is connected between the output end of the inverter and the input end of the transformer, so that the control device for the power generation efficiency of the photovoltaic system can control the switching time point of the switching control device according to the output power characteristic of the power curve of the inverter and the characteristic of the transformer efficiency-transformer load rate, and the transformer can switch different operation states based on the switching time point of the switching control device, thereby changing the loss in the transformer, realizing adjustment and control of the load of the transformer, realizing more efficient operation of the transformer in the whole life cycle of the photovoltaic power generation system, and improving the power generation efficiency of the photovoltaic power generation system.

The switching of the operation state of the transformer is judged according to the power loss of the transformer in different operation states, specifically, the magnitude of the cut-off power loss of the transformer in the cut-off state and the input state loss of the transformer in the input state is compared and judged.

It should be noted that, in this embodiment, fig. 3 is taken as an example, fig. 3 is a topological structure of a photovoltaic power generation system, which is accessed with a switching control device KA and includes a photovoltaic array group, a combiner box group, an inverter group, and a transformer group, where the photovoltaic array group receives solar radiation, converts heat energy generated by the solar radiation into direct current electric energy, sends the direct current electric energy to the combiner box group for combining, sends the combined direct current electric energy to the inverter group, converts the combined direct current electric energy into alternating current electric energy through the inverter group, and sends the boosted alternating current electric energy to a power grid for supplying power after being boosted through the transformer group.

The switching control device KA is controlled through cut-off power loss and input power loss detected by a control device of the generation efficiency of the photovoltaic power generation system, so that the operation state of a transformer bank is controlled, for example, when switching power loss is detected to be smaller than input power loss, a first switching switch Ska1 is controlled to be opened, a second switching switch Ska2 is controlled to be closed, so that the transformer bank is controlled to be in the cut-off state, namely, N1 and N2 are controlled to be jointly connected into B2, at the moment, B2 is a multi-connection transformer, when switching power loss is detected to be larger than input power loss, the first switching switch Ska1 is controlled to be closed, the second switching switch Ska2 is controlled to be opened, namely, N1 is controlled to be connected into B1, and N2 is controlled to be connected into B2, so that the transformer bank is controlled to be in the input power into the transformer bank is changed, so that the load of the transformer bank is controlled, so that the operation efficiency of the transformer bank is changed, the generation efficiency of the photovoltaic power generation system is improved, so that the economic benefit of the photovoltaic power generation system is ensured, but in practical application, the inverter bank composed of a plurality of inverters and a plurality of transformers are divided into a plurality of transformer banks, N2, so that four transformer banks B1 and N2 (4) are divided into four transformer banks, so that B1 and N2, N2 are illustrated below, so that the inverter bank is divided into B3 and N2.

Topology (1): when a first switching switch of the switching control device is connected between the output end of the N1 and the input end of the B1, a second switching switch of the switching control device is connected between the output end of the N1 and the output end of the N2, and a third switching control switch of the switching control device is connected between the output end of the N2 and the output end of the N3, under the state of the topological structure, the switching state of the transformer group is that the N1 is connected to the B1, the N2 is connected to the B2, the N3 is connected to the B3, and the N4 is connected to the B4, namely, inverters in the inverter group are correspondingly connected with transformers in the transformer group one by one, and the switching state is that the N1, the N2 and the N3 are connected to the B1 together, the N2 and the N3 are disconnected from the B2 and the B3, because the switching switch of the switching control device is not connected to the N4 and the B4, the N4 and the B4 are also correspondingly connected, at this moment, the B1 is a multi-connection transformer, the B4 is a common transformer, and the B2 and the B3 are off transformers.

Topology (2): when a first fling-cut switch of a fling-cut control device a is connected between the output end of N1 and the input end of B1, a second fling-cut switch of the fling-cut control device a is connected between the output end of N1 and the output end of N2, a first fling-cut switch of a fling-cut control device B is connected between the output end of N3 and the input end of B3, and a second fling-cut switch of the fling-cut control device B is connected between the output end of N3 and the output end of N4, under the state of the topological structure, the transformer group is in a throw-in state that N1 is connected to B1, N2 is connected to B2, N3 is connected to B3, and N4 is connected to B4, namely inverters in the inverter group are connected with transformers in the transformer group in a one-to-one correspondence manner, and three conditions exist in a cut-off state, the first condition is that N1 and N2 are connected to B1 together, and N3 and N4 are also connected to B3 together, at the moment, B1 and B3 are connected to transformers which are stopped; the second is that N1 and N2 are connected into B1 together, N3 is connected into B3 and N4 is connected into B4, so that B1 is a multi-connection transformer, B2 is a shutdown transformer, and B3 and B4 are ordinary transformers at the moment; the third is that N3 and N4 are connected to B3 together, N1 is connected to B1, N2 is connected to B2, so that at this moment, B3 is a multi-connection transformer, B4 is a shutdown transformer, and B1 and B2 are ordinary transformers.

It should be noted that the topology of the photovoltaic power generation system is not limited to the topology described above, and includes other topologies that can dynamically control the operating state of the transformer bank, which is not specifically limited herein.

Alternatively, referring to fig. 4, the step of acquiring the cut-off power loss of the transformer bank in the cut-off state in step S10 includes:

step S101, calculating a predicted cut-off load rate of a first multi-connection transformer in the multi-connection transformers under the cut-off state according to the target prediction curve and rated parameters of the transformer bank, and calculating the cut-off efficiency of the transformer bank based on the predicted cut-off load rate, wherein the first multi-connection transformer is a multi-connection transformer corresponding to the target prediction curve;

step S102, calculating the cut-off power loss according to the second predicted power curve and the cut-off efficiency.

Since the estimated power curve of the inverter having the same multi-connection transformer is connected in the disconnected state when the target estimated curve is obtained by calculating the disconnection power loss, the estimated disconnection load factor of the multi-connection transformer in the disconnected state can be obtained based on the target estimated curve and the rated parameters of the transformer bank, specifically, the topology state of the topology (2) in the embodiment 1 is taken as an example:

when the situation that the power value of the second predicted power curve 1 is smaller than the rated capacity of the transformer bank is detected, extracting the power curve corresponding to the power value smaller than the rated capacity of the transformer bank to obtain a target predicted curve 1, meanwhile, when the situation that the power value smaller than the rated capacity of the transformer bank is not detected in the second predicted power curve 2, calculating according to the target predicted curve 1 and the rated parameters of the transformer bank to obtain the predicted cut-off load rate of B1 in a cut-off state, calculating according to the predicted cut-off load rate of B1 to obtain the cut-off efficiency of the transformer bank, and finally, obtaining the cut-off power loss of the transformer bank according to the second predicted power curve and the cut-off efficiency obtained by overlapping N1 and N2.

It should be noted that, because the types of the transformers connected to the transformer bank are the same, the rated capacities and rated parameters of the transformers in the transformer bank are the same, and the calculation based on the rated capacities and rated parameters of any transformer does not affect the calculation result, so the rated parameters or rated capacities of the transformer bank are equal to the rated parameters or rated capacities of any transformer in the transformer bank.

Alternatively, referring to fig. 5, the step of acquiring the input power loss of the transformer bank in the input state in step S10 includes:

step S103, acquiring the efficiency of each transformer in the transformer bank;

and step S104, calculating the input power loss according to the first predicted power curve and the efficiency.

Since the input power loss is calculated from the power loss of the transformer bank in the input state, and the input state is a state in which the inverters in the inverter bank are connected to the transformers in the transformer bank, the input power loss is the sum of the power losses of the transformers in the transformer bank, and the power loss of the transformers is calculated from the first predicted power curve of the inverter corresponding to the transformer and the efficiencies of the transformers.

Optionally, the step of obtaining the respective efficiency of each transformer in the transformer bank in step S103 includes:

step S1031, calculating the respective predicted load ratios of the transformers based on the first predicted power curve and the rated parameters of the transformers corresponding to the inverters of the first predicted power curve;

step S1032 is to calculate the efficiency of each of the transformers based on the predicted load factor and the rated parameter of the transformer corresponding to the predicted load factor.

In this embodiment, the rated parameters of the transformers in the transformer bank are obtained according to the types of the transformers and belong to known parameters, the first predicted power curve of the inverter is equivalent to the input power curve of the transformers, and the input power of the transformers is associated with the load ratios of the transformers, so that the predicted load ratios of the transformers can be calculated according to the first predicted power curve of the inverter and the rated parameters of the transformers corresponding to the inverters of the first predicted power curve, and then the predicted load ratios of the transformers and the rated parameters of the transformers corresponding to the predicted load ratios can be substituted into the transformer efficiency formula, so that the efficiency corresponding to each transformer can be obtained.

The transformer efficiency formula is shown as the following formula 1:

wherein, η represents efficiency, P ₁ Representing the input power of the transformer, P ₂ Represents the output work of the transformer, and beta represents the load factor (of the load current and the rated current) of the transformerRatio), S _N The rated capacity of the transformer is used as the rated capacity,

is the power factor, P, of the transformer ₀ For no-load losses (i.e. iron losses), P, of transformers _KN The load loss when the transformer is rated with current.

The reason why the predicted load factor of the transformer is calculated is that the predicted load factor of the transformer is strongly correlated with the mechanical power of the transformer, and when the mechanical power of the transformer is controlled, the predicted load factor of the transformer needs to be controlled, and the predicted load factor is strongly correlated with the predicted power curve of the inverter.

Step S20, when the cut-off power loss is smaller than the input power loss, controlling the transformer bank to enter the cut-off state through the switching control device;

after the cutoff power loss of the transformer bank in the cutoff state and the input power loss of the transformer bank in the input state are obtained, the magnitude between the cutoff power loss and the input power loss is detected and judged.

When the condition that the cut-off power loss is smaller than the input power loss is detected, the condition that the power loss of the transformer bank is smaller than the power loss of the input state in the time period is shown, the cut-off state of the transformer bank is relative to the input state in the time period, therefore, the switching control device controls the transformer bank to enter the cut-off state to operate, the power loss of the transformer bank can be reduced, the load of the transformer bank in the time period is further reduced, the operating efficiency of the transformer bank in the time period is improved, the generating efficiency of the photovoltaic power generation system in the time period is further improved, the problems that the load of the transformer bank is increased and the operating efficiency is reduced when the switch control device does not control the transformer bank to be in the cut-off state are avoided, the generating efficiency of the photovoltaic power generation system is further reduced, and the economic benefit of the photovoltaic power generation system is reduced are further solved.

Optionally, with reference to fig. 6, when it is detected that the cut-off power loss is smaller than the input power loss in step S20, the step of controlling the transformer bank to enter the cut-off state by the switching control device includes:

step 201, when it is detected that the cut-off power loss is smaller than the input power loss within a first power prediction time period or at a first power prediction time, controlling, by the switching control device, the first multi-connection transformer in the transformer bank to enter the cut-off state within the first power prediction time period or at the first power prediction time.

And detecting and counting a time period or moment corresponding to the cut-off power loss being smaller than the input power loss, and recording the counted time period or moment as a first power prediction time period or a first power prediction moment, so that the first power prediction time period or the first power prediction moment corresponds to the time period/moment corresponding to the cut-off power loss being smaller than the input power loss, and simultaneously detecting whether the current time period or the current moment reaches the first power prediction time period or the first power prediction moment so as to ensure that the transformer bank is switched in a correct cut-off state within a correct time period.

When the current time period or the current moment is detected to reach the first power prediction time period or the first power prediction moment, controlling a multi-connection transformer meeting a cut-off condition in a transformer bank to enter a cut-off state, specifically, taking a topological structure of a topology (2) as an example:

when it is detected that the cut-off power loss when the N1 and the N2 are connected to the B1 is smaller than the input power loss when the N1 is connected to the B1 and the N2 is connected to the B2, the first power prediction time period 1 is used, and the cut-off power loss when the N3 and the N4 are connected to the B3 is smaller than the input power loss when the N3 is connected to the B4 and the N4 is connected to the N4, the first power prediction time period 2 is used, when it is detected that the current time period reaches the first power prediction time period 1, the N1 and the N2 are controlled to be connected to the B1 at the moment, the N3, the N4, the B1 and the B2 are kept in a one-to-one connection state, so that the B1 at the moment is a multi-connection transformer, and the cut-off condition is whether the current time period or the current moment reaches the corresponding first power prediction time period or the first power prediction time.

Optionally, with reference to fig. 6, after the step of controlling the transformer bank to enter the cut-off state by the switching control device when it is detected that the cut-off power loss is smaller than the input power loss in step S20, the method further includes:

step S202, calculating the non-loss electric quantity of the photovoltaic power generation system in the cut-off state according to the power loss difference between the input power loss and the cut-off power loss.

When the transformer enters a cut-off state, according to the power loss difference between the input power loss and the cut-off power loss, the power generation efficiency of the whole photovoltaic power generation system, namely the non-loss electric quantity is calculated, and the non-loss electric quantity obtained through calculation is displayed, so that a user can directly and clearly observe the economic benefit improved by the photovoltaic power generation system.

And S30, when the cut-off power loss is detected to be larger than the input power loss, controlling the transformer bank to enter the input state through the switching control device.

After the cut-off power loss of the transformer bank in the cut-off state and the input power loss of the transformer bank in the input state are obtained, the magnitude between the cut-off power loss and the input power loss is detected and judged.

When the condition that the cut-off power loss is larger than the input power loss is detected, the condition that the input state of the transformer bank is smaller than the cut-off state in the time period is shown, the power loss of the transformer bank is smaller than the power loss of the cut-off state in the time period, therefore, the transformer is controlled to enter the input state to operate through the switching control device, the power loss of the transformer bank can be reduced, the load of the transformer bank in the time period is further reduced, the operating efficiency of the transformer bank in the time period is improved, the generating efficiency of the photovoltaic generating system in the time period is further improved, the stability and the economic benefit of the photovoltaic generating system are further ensured, the operating state of the transformer bank is controlled and switched through the switching control device, and the problem that the operating efficiency of the transformer bank in a certain time period is low due to the fact that the load in the single operating state of the existing transformer bank cannot be adjusted in real time, and the generating efficiency of the photovoltaic generating system is further reduced inevitably is solved.

Optionally, when it is detected in step S30 that the cut-off power loss is greater than the input power loss, the step of controlling, by the switching control device, the transformer bank to enter the input state includes:

step 301, when it is detected that the cut-off power loss is greater than the input power loss within a second power prediction time period or at a second power prediction time, controlling, by the switching control device, the transformer bank to enter the input state within the second power prediction time period or at the second power prediction time.

And checking and counting the time period or moment corresponding to the fact that the cut-off power loss is larger than the input power loss, and marking the counted time period or moment as a second power prediction time period or a second power prediction moment, so that whether the current time period or the current moment reaches the second power prediction time period or the second power prediction moment is detected when the cut-off power loss is larger than the input power loss, and the transformer group is ensured to be switched in a correct cut-off state in the correct time period.

When the current time period or the current moment is detected to reach the second power prediction time period or the second power prediction moment, controlling the transformer meeting the input condition in the transformer bank to enter the input state, specifically, taking the topological structure of the topology (2) as an example:

when the fact that the input power loss of N1 connected with B1 and N2 connected with B2 is smaller than that of N1 and N2 connected with B1 is detected to be a second power prediction time period 1, and the cut-off power loss of receiving N3 and N4 connected with B3 corresponding to the second power prediction time period 1 is smaller than a first power prediction time period 3 of N3 connected with B4 and N4 connected with N4, therefore, when the fact that the current time period reaches the second power prediction time period 1 is detected, the connection of N1 with B1 and N2 with B2 is controlled, namely, B1 and B2 are controlled to enter an input state, N3 and N4 are controlled to be connected with B3 together, and therefore the input condition is whether the current time reaches the corresponding second power prediction time period or the corresponding first power prediction time.

In this embodiment, the photovoltaic power generation system shown in fig. 3 is taken as an example to perform measurement and calculation, and the power loss reduced by the switching control device is solved. The rated parameters of the transformer bank are shown in fig. 7, the efficiency-load rate curve of the transformer bank is shown in fig. 8, and the predicted power curves of the first inverter and the second inverter are shown in fig. 9, wherein, the ratio of 5.

According to the following, when the power value of the inverter group is less than 1000kVA in the 5-10 30 period and 16-19 15 period (i.e. the first target period), the following power value is calculated step by step in the control method of the power generation efficiency, according to the following.

Further calculating the relationship between the magnitude of the cut-off power loss and the magnitude of the input power loss, and assuming that the cut-off power loss is smaller than the input power loss in the following time periods of 5-9 and 17-00 and 17-19 (namely, in a first power prediction time period), so that the operation state of the transformer bank in the time periods of 5-9 and 17-00-19 is controlled by the switching control device to be a cut-off state.

Assuming that the input power loss is smaller than the cut power loss in the period of 9-10 and in the period of 16-15-17 (i.e., the second power prediction period), according to the magnitude detection judgment between the cut power loss and the input power loss, the operating state of the transformer bank in the period of 9. In the following, the reason why the input state is in the period 9-16 is that, in the period 9.

Thereby avoiding the situation shown in fig. 8, in which the efficiency of the transformer bank drops from the optimal efficiency of 99.2% when the load factor of the transformer bank reaches 52%.

By reducing the transformer power loss in the cut-off state by the reduced amount delta = input power loss-cut-off power loss, the loss electric quantity (namely, non-loss electric quantity) avoided by the transformer bank due to the switching control device is further obtained, and according to the non-loss electric quantity, the generation efficiency improvement ratio of the photovoltaic power generation system connected with the switching control device compared with the photovoltaic power generation system not connected with the switching control device can be directly and clearly observed.

In the embodiment, the cut-off power loss of the transformer bank in the cut-off state and the input power loss of the transformer bank in the input state are obtained, and when the cut-off power loss is smaller than the input power loss, the photovoltaic power generation system is controlled to enter the cut-off state through the switching control device; and when the cut-off power loss is detected to be larger than the input power loss, the photovoltaic power generation system is controlled to enter an input state through the switching control device. According to the invention, the cut-off power loss of the transformer bank and the input power loss of the transformer bank are detected, and the control device controls the transformer bank to enter different operation states according to the detection result, so that the operation efficiency of the transformer bank is controlled, the power generation efficiency of the photovoltaic power generation system can approach to the optimal power generation efficiency, the safety and stability of the photovoltaic power generation system are ensured, and the economic operation of the photovoltaic power generation system is promoted.

Further, based on the above first embodiment of the method for controlling the generating efficiency of the photovoltaic power generation system of the present invention, a second embodiment of the method for controlling the generating efficiency of the photovoltaic power generation system of the present invention is provided.

Referring to fig. 11, in the second embodiment of the method for controlling the power generation efficiency of the photovoltaic power generation system according to the present invention, before the step of obtaining the cut-off power loss of the transformer bank in the cut-off state and the step of obtaining the input power loss of the transformer bank in the input state in step S10, the method further includes:

step A, acquiring a first predicted power curve of each inverter in the inverter group in a predicted time period;

specifically, in this embodiment, a power prediction method is used to obtain respective first predicted power curves of all inverters in an inverter group of the photovoltaic power generation system.

Further, the power prediction method comprises direct prediction and indirect prediction according to predicted physical quantities, wherein the direct prediction is to directly predict the output power of the inverter, the indirect prediction is to predict the solar irradiation quantity, and then the output power of the inverter is estimated according to the predicted solar irradiation quantity; the power prediction method can be classified according to applied mathematical models and can be classified into a time series prediction method, an autoregressive moving average model method, a neural network method, a support vector machine method and the like, wherein the time series prediction method is used for predicting the output power of the inverter in a single time series, the autoregressive moving average model method is used for searching the correlation between the output power of the inverter and the influence factors through regression analysis, establishing a regression model for prediction, or researching the relationship between the output power of the inverter and the influence factors according to the given output power and influence factor data of the inverter to form a regression equation, or giving respective variable values according to the regression equation to obtain the dependent variable values, namely the output power of the inverter, and the like, which are not repeated herein.

The output power of the inverter within a certain period of time is obtained based on a power prediction method, for example, the output power of the inverter within a day is obtained, because the output power has strong correlation with weather irradiation, and the weather irradiation changes in real time, the output power of the inverter within a day obtained at this time is shown in a power curve, so the first predicted power curve is a preset power value shown according to different times in a day, a specific predicted power curve is based on an actual power curve, and the embodiment is not limited.

In this embodiment, the first predicted power curve obtained in the prediction time period is a power curve in the switching control cycle, that is, the operation state of the transformer bank may be switched in the prediction time period.

Step B, superposing the first predicted power curves of the inverters connected to the same multi-connection transformer in the cut-off state to obtain a second predicted power curve of the inverter group;

in the prediction time period, a first prediction power curve of the inverter connected with the same multi-connection transformer is superposed, namely the inverter connected with the same multi-connection transformer is regarded as an inverter (hereinafter referred to as a grouped inverter for distinguishing), so that first prediction power superposed as the inverter connected with the same multi-connection transformer is poured on the grouped inverter, and a second prediction power curve of the grouped inverter in the prediction time period is obtained.

The second predicted power curve is obtained by superposing the first predicted power curves of the inverters connected with the same multi-connection transformer under the condition that the transformer bank is in a cut-off state, and if the power curve obtained by superposing the first predicted power curves of all the inverters is used as the second predicted power curve, the power curve causes errors in subsequent control operation of the switching control device, and further causes that the photovoltaic power generation system cannot obtain a substantial discharge power generation efficiency improvement effect.

Step C, detecting whether a target prediction curve exists, wherein the power value of the second prediction power curve is smaller than the rated capacity of the transformer bank;

and step D, when it is detected that the target prediction curve in which the power value of the second prediction power curve is smaller than the rated capacity of the transformer bank exists, performing the steps of acquiring the cut-off power loss of the transformer bank in the cut-off state and acquiring the input power loss of the transformer bank in the input state within a first target time period or at the first target time corresponding to the target prediction curve.

When there is a topology structure like the topology (2) in the first embodiment, there are two second predicted power curves at this time, that is, when N1 and N2 are connected to B1, the second predicted power curve 1 obtained by superimposing the first predicted power curves of N1 and N2, and when N3 and N4 are connected to B3, the second predicted power curve 2 obtained by superimposing the first predicted power curves of N3 and N4, and at this time, it is necessary to determine whether or not the power values of the second predicted power curve 1 and the second predicted power curve 2 in the prediction time period are smaller than the rated capacity of the transformer group.

When the situation that the power value is smaller than the rated capacity of the transformer bank exists in the second predicted power curve 1 and/or the second predicted power curve 2 is detected, the power curve corresponding to the power value smaller than the rated capacity of the transformer bank is extracted to obtain a target predicted curve 1 and/or a target predicted curve 2, and the time period or moment corresponding to the target predicted curve 1 and/or the target predicted curve 2 is the first target time period 1 and/or the first target time period 2, or the target moment 1 and/or the target moment 2.

The target power curve is detected on the second predicted power curve, because the transformer bank has an upper limit, before the operation state of the transformer is controlled by the switching control device, whether the transformer bank can bear the output power of the current inverter bank needs to be detected to ensure the safety of the transformer bank, and the judgment of whether the transformer is controlled to enter the cut-off state (namely, the steps of obtaining the cut-off power loss of the transformer bank in the cut-off state and obtaining the input power loss of the transformer bank in the input state) can be carried out only when the power value (namely, the output power) in the first predicted power curve is smaller than the rated capacity of the transformer bank, so that the overload phenomenon of the transformer is avoided. And then guarantee photovoltaic power generation system's safety and stability.

The first target time period refers to a certain time period a in the prediction time period when a certain power value in the second prediction power curve is detected to be smaller than the rated capacity of the transformer bank, and the certain time period a is the first target time period, and the first target time is the same.

Optionally, after the step of detecting whether there is a target prediction curve in which the power value of the second prediction power curve is smaller than the rated capacity of the transformer bank in step C, the method further includes:

and step C1, when detecting that the power value of the second predicted power curve in a second target time period or at a second target moment is greater than the rated capacity of the transformer bank, controlling the transformer bank to enter the switching state in the second target time period or at the second target moment through the switching control device.

When the situation that the power value is larger than the rated capacity of the transformer bank is detected in the second predicted power curve, the situation that the transformer bank is overloaded exists when the operation state of the transformer bank is controlled to be a cut-off state through the switching control device at the moment, therefore, in order to ensure the safe operation of the transformer bank, the transformer bank is controlled to operate according to the original operation state in a time period or moment (namely a second target time period or a second target moment) corresponding to the power curve that the power value of the second predicted power curve is larger than the rated capacity of the transformer bank, namely, an inverter in the inverter bank is controlled to be correspondingly connected with the transformer in the transformer bank, and the situation that the transformer bank is overloaded is avoided.

The second target time period refers to a time period b in the prediction time period when it is detected that a certain power value in the second prediction power curve is greater than the rated capacity of the transformer bank, the certain time period b is the second target time period, because the second target time period is a prediction for the future, when the current time reaches the second target time period, it is indicated that the switching control device controls the transformer bank to enter the switching state corresponding to the current time, and the second target time is the same.

In the embodiment, a first predicted power curve of each inverter in an inverter group in a predicted time period is obtained, the first predicted power curves of each inverter connected to the same multiple-connection transformer in a cut-off state are superposed to obtain a second predicted power curve of the inverter group, whether a target predicted curve with the power value of the second predicted power curve being smaller than the rated capacity of the transformer exists or not is detected, when the target predicted curve with the power value of the second predicted power curve being smaller than the rated capacity of the transformer is detected, the steps of obtaining the cut-off power loss of the transformer group in the cut-off state and obtaining the input power loss of the transformer group in the input state are executed in a first target time period or at a first target moment corresponding to the target predicted curve, so as to ensure the safety of the transformer group, and only when the power value (namely, output power) in the second predicted power curve is smaller than the rated capacity of the transformer group, judgment on whether the transformer is controlled to enter the cut-off state or not can be carried out, so as to avoid the overload phenomenon of the transformer, and further ensure the safety and stability of the photovoltaic power generation system.

Referring to fig. 12, the present invention provides a control apparatus for generating efficiency of a photovoltaic power generation system, including:

an obtaining module 10, configured to obtain a cut-off power loss of the transformer bank in a cut-off state and obtain an input power loss of the transformer bank in an input state, where the input state is a state where an inverter in the inverter bank is correspondingly connected to a transformer in the transformer bank, the cut-off state is a state where at least one multiple transformer is present in the transformer bank, and the multiple transformer is a transformer that simultaneously connects at least two inverters in the inverter bank;

the control module 20 is configured to control the transformer bank to enter the cut-off state through the switching control device when it is detected that the cut-off power loss is smaller than the input power loss;

the control module 20 is further configured to control the transformer bank to enter the input state through the switching control device when it is detected that the cut-off power loss is greater than the input power loss.

Further, the obtaining module 10 is configured to:

Further, the control module 20 is configured to:

and when detecting that the power value of the second predicted power curve in a second target time period or at a second target moment is larger than the rated capacity of the transformer bank, controlling the transformer bank to enter the switching state in the second target time period or at the second target moment through the switching control device.

Further, the obtaining module 10 is configured to:

calculating a predicted cut-off load rate of a first multi-connection transformer in the multi-connection transformers in the cut-off state according to the target prediction curve and rated parameters of the transformer bank, and calculating cut-off efficiency of the transformer bank based on the predicted cut-off load rate, wherein the first multi-connection transformer is a multi-connection transformer corresponding to the target prediction curve;

Further, the control module 20 is configured to:

when the cut-off power loss is detected to be smaller than the input power loss within a first power prediction time period or at a first power prediction time, the first multi-connection transformer in the transformer bank is controlled to enter the cut-off state within the first power prediction time period or at the first power prediction time through the switching control device.

Further, the obtaining module 10 is configured to:

Further, the control module 20 is configured to:

when the fact that the cut-off power loss is larger than the input power loss is detected in a second power prediction time period or at a second power prediction time, the switching control device controls the transformer bank to enter the input state in the second power prediction time period or at the second power prediction time.

Further, the obtaining module 10 is configured to:

In addition, the invention also provides a control device system of the generating efficiency of the photovoltaic generating system, the control device system of the generating efficiency of the photovoltaic generating system comprises a controller and the photovoltaic generating system, the photovoltaic generating system comprises an inverter group, a switching control device and a transformer group, and the controller is used for executing the steps of the control method of the generating efficiency of the photovoltaic generating system.

In addition, the invention also provides a computer readable storage medium, wherein the computer readable storage medium stores a control program, and the control program realizes the steps of the control method for the power generation efficiency of the photovoltaic power generation system when being executed by a processor.

It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or system 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 system. Without further limitation, an element defined by the phrases "comprising a," "8230," "8230," or "comprising" does not exclude the presence of other like elements in a process, method, article, or system comprising the element.

The above-mentioned serial numbers of the embodiments of the present invention are only for description, and do not represent the advantages and disadvantages of the embodiments.

Through the description of the foregoing embodiments, it is clear to those skilled in the art that the method of the foregoing embodiments may be implemented by software plus a necessary general hardware platform, and certainly may also be implemented by hardware, but in many cases, the former is a better implementation. Based on such understanding, the technical solution of the present invention or the portions contributing to the prior art may be embodied in the form of a software product, which is stored in a storage medium (such as ROM/RAM, magnetic disk, optical disk) as described above and includes several instructions for enabling a terminal device (which may be a mobile phone, a computer, a server, an air conditioner, or a network device) to execute the method according to the embodiments of the present invention.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, and all equivalent structures or equivalent processes performed by the present invention or directly or indirectly applied to other related technical fields are also included in the scope of the present invention.

Claims

1. A control method for the generating efficiency of a photovoltaic power generation system is characterized in that the photovoltaic power generation system comprises an inverter group, a switching control device and a transformer group, and the control method for the generating efficiency of the photovoltaic power generation system comprises the following steps:

2. The method for controlling generation efficiency of a photovoltaic power generation system according to claim 1, wherein the step of obtaining a cut-off power loss of the transformer bank in a cut-off state and obtaining an input power loss of the transformer bank in an input state is preceded by the step of:

3. The method for controlling power generation efficiency of a photovoltaic power generation system according to claim 2, wherein the step of detecting whether or not there is a target prediction curve in which the power value of the second prediction power curve is smaller than the rated capacity of the transformer bank is followed by further comprising:

4. The method for controlling generation efficiency of a photovoltaic power generation system according to claim 2, wherein the step of acquiring a cut-off power loss of the transformer bank in a cut-off state includes:

5. The method for controlling generation efficiency of a photovoltaic power generation system according to claim 4, wherein the step of controlling the transformer bank to enter the cut-off state by the switching control device when it is detected that the cut-off power loss is smaller than the input power loss includes:

6. The method for controlling the generating efficiency of the photovoltaic power generating system according to claim 2, wherein the step of obtaining the input power loss of the transformer bank in the input state includes:

7. The method for controlling the generating efficiency of a photovoltaic power generating system according to claim 6, wherein the step of obtaining the respective efficiency of each of the transformers in the transformer bank comprises:

8. The method for controlling the generating efficiency of the photovoltaic power generating system according to claim 2, wherein the step of controlling the transformer bank to enter the input state by the switching control device when detecting that the cut-off power loss is larger than the input power loss comprises:

9. The method according to any one of claims 1 to 8, wherein, after the step of controlling the transformer bank to enter the cut-off state by the switching control device when the cut-off power loss is detected to be smaller than the input power loss, the method further comprises:

10. The utility model provides a photovoltaic power generation system generating efficiency's controlling means which characterized in that, photovoltaic power generation system includes inverter group, switching controlling means and transformer bank, photovoltaic power generation system generating efficiency's controlling means includes:

11. A control device system for the power generation efficiency of a photovoltaic power generation system, which is characterized by comprising a controller and the photovoltaic power generation system, wherein the photovoltaic power generation system comprises an inverter group, a switching control device and a transformer group, and the controller is used for executing the steps of the control method for the power generation efficiency of the photovoltaic power generation system according to any one of claims 1 to 9.

12. A computer-readable storage medium, characterized in that the computer-readable storage medium has stored thereon a control program which, when executed by a processor, realizes the steps of the control method of power generation efficiency of a photovoltaic power generation system according to any one of claims 1 to 9.