CN201918409U - Novel photovoltaic confluence box - Google Patents

Abstract

A new type of photovoltaic combiner box, lightning protector, battery array, DC bus, DC circuit breaker, output terminal, and a DC converter connected with the lightning protector and DC bus. The lightning protector and DC converter are connected in parallel . The beneficial effect of the utility model lies in that it can solve the matching failure problem of the photovoltaic battery, and at the same time increase the current and voltage detection function and provide the leakage current protection function.

Description

A new photovoltaic combiner box

technical field

The utility model belongs to the field of solar photovoltaic power generation systems and relates to a novel photovoltaic combiner box.

technical background

In large-scale photovoltaic power plants, due to the small capacity of a single set of photovoltaic cell components, it is difficult to meet the requirements of megawatt-level photovoltaic power plants. The user connects a certain number of photovoltaic cells with the same specifications in series to form a photovoltaic series, and then connects several photovoltaic series in parallel to the photovoltaic combiner box. The inverter is used together to form a complete photovoltaic power generation system and realize grid connection with the mains. Therefore, the photovoltaic combiner box plays a key role in gathering the number of multi-channel photovoltaic branches. The exterior of the photovoltaic combiner box is made of a metal box, with input and output terminal interfaces, the internal connection is connected by copper wires or copper bars, and the output has a DC circuit breaker.

Due to the incomplete occlusion of the cloud cover in the sky, the photovoltaic cell modules in the shaded part cannot generate electricity, resulting in multiple local maximum power points in the output power curve of the group of photovoltaic cell arrays. This phenomenon is called the partial shadow phenomenon. In this state, the maximum output power of the photovoltaic cell array is far less than the sum of the output power of all single photovoltaic cell components, resulting in the loss of power generation efficiency of the photovoltaic power station. This situation is called matching failure.

At the same time, countries around the world have formulated relevant standards (such as DIN V VDE0126-1-1) for photovoltaic power generation systems, which make strict regulations on leakage current.

Contents of the invention

The purpose of this utility model is to provide a new type of photovoltaic combiner box, which adds a DC converter inside and has the function of maximum output power tracking (MPPT) of photovoltaic cells, which can solve the problem of photovoltaic cell matching failure, and also increase current and voltage detection functions, providing The leakage current protection function meets the requirements of network access regulations and standards.

In order to achieve the above-mentioned purpose of the invention, the utility model adopts the following technical solutions:

A new type of photovoltaic combiner box, including a lightning arrester, battery array, DC bus, DC circuit breaker, output terminal, and a DC converter connected to the lightning arrester and DC bus, and the lightning arrester and DC converter are connected in parallel relation.

The utility model can also include a controller for controlling DC voltage sampling.

The beneficial effect of the utility model lies in that it can solve the matching failure problem of the photovoltaic battery, and at the same time increase the current and voltage detection function and provide the leakage current protection function.

Description of drawings

Fig. 1 is a structural representation of the utility model.

Detailed ways

The specific functions, features and working methods of the utility model will be described in detail in conjunction with the accompanying drawings through examples. The following example is only an embodiment of the utility model, and is not a limitation of the utility model.

In Figure 1, it includes DC photovoltaic fuse, input current sampling, output voltage sampling, output circuit breaker, DC converter, and controller.

1 in Figure 1 includes the input of most photovoltaic branches, and the positive and negative ends of each branch contain fuses. The controller can sample the current of each branch and the parallel voltage at the output.

In Fig. 1, the faulty branch can be accurately judged, and the faulty branch can be effectively disconnected.

In Figure 1, the positive and negative terminal current of the branch can be sampled to judge and calculate the leakage current to the ground, and it can alarm and protect.

In Figure 1, corresponding lightning protection devices and external communication interfaces are also equipped.

Device description: The device mainly includes input terminals, input anti-reverse diodes, input overcurrent fuses, DC busbars, DC converters, input and output circuit breakers, input lightning protection units and control modules, etc.

The external photovoltaic cell is first connected to the input terminal, and the current starts from the terminal, and then passes through the input anti-reverse diode, input fuse, DC busbar (+), DC converter, and output terminal (+) to the external load. After the current flows through the external load, it passes through the output terminal (-), the DC converter, the DC busbar (-), enters the fuse, and then reaches the input terminal. The anti-reverse diodes are connected in series in the circuit to prevent the current from flowing in the opposite direction and destroying the photovoltaic cell components. The input fuse cuts off the entire circuit when the current exceeds a certain limit value.

The surge protector is connected between the input DC bus and the ground. There is current and voltage sampling at the input end, and voltage sampling at the output end, and the sampled signals are sent to the control module, and the control module controls the opening and closing of the DC converter and the output circuit breaker.

Claims (2)

1. a novel photovoltaic header box comprises lightning protection device, array, dc bus, dc circuit breaker, lead-out terminal, it is characterized in that, also comprise the DC converter that is connected with dc bus, lightning protection device is serially connected between dc bus and the ground wire.

2. a kind of novel photovoltaic header box according to claim 1 is characterized in that, comprises a converter that is used to control input direct voltage.

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