Photovoltaic power generation equipment for small buildings

Abstract

The utility model discloses photovoltaic power generation equipment for small buildings, which comprises photovoltaic assemblies, the photovoltaic assemblies form a plurality of photovoltaic strings, each photovoltaic string is connected with an input interface of a step-up and step-down circuit, the step-up and step-down circuits have the same output voltage, the output ends of the step-up and step-down circuits are connected through an MPPT (maximum power point tracking) input line, and the MPPT input line is connected with the input interface of the step-up and step-down circuit. Each photovoltaic group string is in one-way conduction with the MPPT input line, the MPPT input line is connected to the input end of the MPPT, and the output end of the MPPT is connected to an energy storage device or an inversion device. By adopting the photovoltaic power generation equipment for the small building, the photovoltaic assemblies can be installed by fully utilizing the roof or wall surface resources of the small building, and the generating capacity of each installed photovoltaic assembly can be fully output.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of photovoltaic power generation equipment, especially a kind of distributed photovoltaic power generation equipment installed on small building. BACKGROUND

[0002] The photovoltaic power generation equipment for small building is mainly applied in the occasion such as family house building, and the photovoltaic module thereof is installed on the roof or wall of house. Generally, the photovoltaic module of photovoltaic power generation equipment needs to be placed towards the sun, and the installation direction of each photovoltaic module needs to be consistent to achieve ideal power generation effect. Due to the diversification of roof structure of family house building, especially some villa type house building for the sake of beauty and other factors, the roof of house is not uniformly north-south oriented, but east-west-south-north oriented differently, and there may also exist different pitch angles, which brings great problem to the installation of photovoltaic equipment on small building. In order to ensure the power generation efficiency, photovoltaic installation support for installing photovoltaic module needs to be built on the roof, so that the photovoltaic module can have uniform orientation and pitch angle. However, this way has safety risk of the built photovoltaic support on one hand, and affects the beauty of house on the other hand, which is difficult to accept.

[0003] In order to not destroy the appearance of the building, the ideal way to install photovoltaic power generation equipment on the building is to attach each photovoltaic module to the corresponding roof or wall, but this will make the power generated by the photovoltaic modules on the roofs or walls with different orientations vary greatly, and if each photovoltaic module is connected in series to form a photovoltaic string and then connected to an inverter, the consistency of voltage and current needs to be ensured, otherwise the sum of the power generated by each photovoltaic module can only be subject to the minimum power of the photovoltaic module, which is not desirable. If the photovoltaic modules on the roofs or walls with different orientations are connected in series to form photovoltaic strings, each photovoltaic string needs to be connected to a different inverter to fully output the power generated by each photovoltaic module, but this is only limited to grid-connected photovoltaic power generation equipment, and the cost is increased, and if it is off-grid, there is a problem of AC bus connection that needs to be solved and cannot be conveniently realized. If a single inverter is used, it has multiple MPPT modules, and the MPPT modules can adjust the output voltage and current of the photovoltaic module in real time under the condition of constantly changing light and temperature, ensure that the system always works at the highest efficiency point, i.e. the maximum power point, and through complex algorithms such as perturb and observe and incremental conductance, MPPT can significantly improve the overall energy output of the photovoltaic system. Each photovoltaic string is connected to the input port of an MPPT module, which seems to be feasible, but a single inverter often cannot have enough MPPT modules. In addition, since the areas of the roofs or walls with different orientations are different, the number of photovoltaic modules that can be installed is also different, and if the photovoltaic modules on each roof or wall with different orientations are connected in series to form photovoltaic strings, the number of photovoltaic modules on some roofs is small, and the voltage of the photovoltaic string formed after being connected in series cannot reach the minimum voltage requirement of the MPPT and cannot be used, so that photovoltaic power generation equipment cannot be fully and efficiently installed on such small buildings. Content of the utility model

[0004] In view of the above-mentioned deficiencies of the prior art, the technical problem to be solved by the utility model is to provide a photovoltaic power generation equipment for small buildings, which can fully utilize the roof or wall resources of small buildings to install photovoltaic modules and fully output the power generated by each photovoltaic module.

[0005] In order to solve the above technical problem, the utility model provides a photovoltaic power generation equipment for small buildings, which comprises photovoltaic modules, the photovoltaic modules form multiple photovoltaic strings, each photovoltaic string is connected to the input interface of a step-up and step-down circuit, each step-up and step-down circuit has the same output voltage, the output ends of each step-up and step-down circuit are connected through an MPPT input line, the MPPT input line is connected to the input end of an MPPT, and the output end of the MPPT is connected to an energy storage device or an inverter device.

[0006] According to the technical scheme, each photovoltaic module can be installed on the roof or wall of the small building in different orientations (including azimuth angle and elevation angle) as required, the roof or wall resource of the building is fully utilized, the photovoltaic modules with the same azimuth angle and the same elevation angle are connected in series to form a photovoltaic module string, each photovoltaic module string is connected with the input interface of the corresponding boost-buck circuit, the voltages of the photovoltaic module strings are different in the working process, but the same output voltage is obtained after the boost-buck circuit is regulated, and the output voltage value meets the input voltage range requirement of MPPT, so that the photovoltaic module string with a small number of photovoltaic modules can also effectively output the generated power; the output ends of the boost-buck circuits with the same output voltage are connected through the MPPT input line, so that the photovoltaic module strings can be combined into one output, the MPPT input line is connected to the input port of the MPPT, and the maximum power tracking control is realized through the MPPT, so that the power generation efficiency of each photovoltaic module is ensured, and all the generated power can be input to the energy storage device for energy storage or be converted into alternating current through the inverter to supply power to the load.

[0007] In an embodiment of the utility model, each photovoltaic module string and the MPPT input line are unidirectionally conducted. In this way, when the output voltage of a certain photovoltaic module string is higher or lower than the set value due to the failure of the boost-buck circuit corresponding to the photovoltaic module string, the corresponding photovoltaic module string can be prevented from being damaged.

[0008] In another embodiment of the utility model, a diode is connected in series between each photovoltaic module string and the MPPT input line. In this way, the diode connected in series can meet the unidirectional conduction requirement of the line.

[0009] In still another embodiment of the utility model, the boost-buck circuit is a conventional boost circuit, a buck circuit or a boost-buck circuit. In this way, the boost circuit is used in the case where the output voltage of a certain photovoltaic module string is lower than the MPPT input voltage range, the buck circuit is used in the case where the output voltage of a certain photovoltaic module string is higher than the MPPT input voltage range and the photovoltaic module string cannot be divided into two photovoltaic module strings, and the boost-buck circuit has the characteristics of both boosting and bucking, so that the variety of boost-buck circuits can be reduced, and the procurement and management are facilitated.

[0010] In a further embodiment of the utility model, the energy storage device is connected with an energy storage converter. In this way, the energy storage converter can control the charging and discharging process of the energy storage device, convert AC and DC, directly supply power to the AC load in the case where there is no power grid, and charge or discharge the energy storage device, so that the active power and reactive power of the power grid can be adjusted, and the photovoltaic power generation equipment has higher value.

[0011] The utility model discloses a further preferred embodiment, the MPPT is set up in the MPPT module of inverter, the inverter device is the inverter unit in inverter, the MPPT input circuit is connected with the MPPT input interface on inverter. Adopt this embodiment, MPPT is connected directly with inverter, and the electric energy of each photovoltaic module can be converted into alternating current to provide the electric energy for alternating current load. BRIEF DESCRIPTION OF DRAWINGS

[0012] The utility model discloses small building photovoltaic power generation equipment makes further detailed explanation in combination with the specific embodiment and the drawing.

[0013] Figure 1 It is the structural principle schematic diagram of one specific embodiment of the utility model small building photovoltaic power generation equipment;

[0014] Figure 2 It is the structural principle schematic diagram of another specific embodiment of the utility model. CONCRETE EMBODIMENT

[0015] In Figure 1 And Figure 2In the small building photovoltaic power generation device shown, a plurality of photovoltaic modules are installed on each roof or wall surface of the small building facing in different directions, according to the different installation positions, the photovoltaic modules facing in the same direction are connected in series to form a plurality of photovoltaic strings, the photovoltaic modules in each photovoltaic string have the same azimuth angle and elevation angle, the output line of each photovoltaic string is connected to the input interface of a boost-buck circuit, the boost-buck circuits have the same output voltage, the output voltage can meet the input voltage range requirement of MPPT, the output ends of the boost-buck circuits are connected through an MPPT input line, the MPPT input line has a plurality of input ends corresponding to the number of photovoltaic strings and an output end, in this way, the electric energy generated by each photovoltaic string with different azimuth angle and elevation angle can be effectively combined into one output through the MPPT input line. As a preferred embodiment, the boost-buck circuit can be a boost circuit (topology structure is Boost) or a buck circuit (topology structure is Buck) or a buck-boost circuit (topology structure is Buck-Boost) with a conventional control strategy of PWM (pulse width modulation), of course, it can also be other types of boost-buck circuits, the determined boost-buck circuit is made into a boost-buck module, the input interface and the output interface are arranged on the boost-buck module, the input interface is connected to the output line of the corresponding photovoltaic string, and the output interface is connected to an input end of the MPPT input line; each photovoltaic string to the MPPT input line is unidirectional conduction, which can be simply realized by connecting a diode between each photovoltaic string and the MPPT input line, of course, other unidirectional conduction circuits can also be used, and the diode or the unidirectional conduction circuit is also arranged in the boost-buck module.

[0016] As shown in Figure 1 The output end of the MPPT input line is connected to the input end of the MPPT, the MPPT is an independent maximum power point tracking controller, the output end of the MPPT is connected to the energy storage device, and the direct current electric energy generated by the photovoltaic modules is stored in the energy storage device, and the energy storage device is preferably a lithium battery energy storage device. As a preferred embodiment, the energy storage device is connected to the energy storage converter, so that the direct current electric energy generated by the photovoltaic modules can be converted into alternating current to supply power to the alternating current load.

[0017] Figure 2 Another embodiment of the utility model is shown, the MPPT connected to the output end of the MPPT input line is an MPPT module arranged in the inverter, the output end of the MPPT is connected to the inverter device, and the inverter device is an inverter unit in the inverter, so that the MPPT input line is connected to the MPPT input interface on the inverter, and the direct current electric energy generated by the photovoltaic modules can be converted into alternating current to provide electric energy for the alternating current load or send power to the power grid.

[0018] The above only lists some preferred embodiments of the present application, but the present application is not limited thereto, and many improvements and changes can be made. As long as the improvements and changes are made on the basis of the basic principles of the present application, they should be considered to fall within the protection scope of the present application.

Claims

1. A photovoltaic power generation device for a small building, comprising a photovoltaic module, characterized by: The photovoltaic assembly constitutes a plurality of photovoltaic strings, each of which is connected to an input interface of a boost-buck circuit, each of the boost-buck circuits has the same output voltage, and output ends of the boost-buck circuits are connected through an MPPT input line, the MPPT input line is connected to an input end of an MPPT, and an output end of the MPPT is connected to an energy storage device or an inverter device.

2. The small-sized building photovoltaic power generation device according to claim 1, characterized by: Each of the photovoltaic strings is unidirectionally connected to the MPPT input line.

3. The small building photovoltaic power generation device according to claim 2, characterized by: A diode is connected in series between each of the photovoltaic strings and the MPPT input line.

4. The small building photovoltaic power generation device according to claim 1, characterized by: The boost-buck circuit is a conventional boost circuit, a buck circuit or a boost-buck circuit.

5. The small building photovoltaic power generation device according to claim 1, characterized by: The energy storage device is connected to an energy storage converter.

6. The small building photovoltaic power generation device according to claim 1, characterized by: The MPPT is an MPPT module arranged in an inverter, the inverter device is an inverter unit in the inverter, and the MPPT input line is connected to an MPPT input interface on the inverter.

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