CN203056672U - Photovoltaic DC off-grid system - Google Patents

Abstract

The utility model relates to a photovoltaic direct-current off-grid system, comprising a photovoltaic cell array, a photovoltaic controller connected with the photovoltaic cell array, a storage cell connected with the photovoltaic controller, a low-voltage converting circuit connected with the photovoltaic controller and used for outputting a low-voltage direct-current voltage, and a high-voltage boost circuit connected with the photovoltaic controller and used for outputting a high-voltage direct-current voltage. According to the photovoltaic direct-current off-grid system of the utility model, the low-voltage converting circuit and the high-voltage boost circuit which are respectively used for outputting the low-voltage direct-current voltage and the high-voltage direct-current voltage are directly connected to the photovoltaic controller, thus high and low voltage separated and direct power supply can be realized, and the program of electric power conversion is simplified, thereby contributing to raising a utilization rate of photovoltaic power generation and reducing cost.

Description

Photovoltaic DC off-grid system

technical field

The utility model relates to a photovoltaic DC off-grid system.

Background technique

Renewable clean energy is one of the most decisive technical fields in the development of the world economy in the 21st century. It has the advantages of ubiquity, inexhaustibility, and no environmental pollution. It plays an increasingly important role in the sustainable development of energy in the world and in my country. big effect. A photovoltaic system is a system that converts solar energy into electrical energy using solar cell modules and other auxiliary equipment.

At present, the common photovoltaic off-grid systems are nothing more than DC power supply system and AC power supply system. Generally, the DC power supply system is used off-grid in the small and medium power range, and the AC power supply system is used off-grid in the slightly larger power range (see Figure 1. ).

The commonly used household load power supply is AC, but most of the input circuits are powered by a rectifier circuit to convert AC into DC (see Figure 2), but in fact many loads used can be passed DC power supply is realized. Therefore, it can be considered to realize power supply through DC power distribution alone.

At present, Light Emitting Diode (LED) and Compact Fluorescent Lamp (CFL) for lighting can realize low-voltage DC power supply, and small DC motors such as DC fans and DC pumps are also widely used. The power is relatively small, so the advantage of low-voltage power supply is obviously higher than that of high-voltage power supply.

Now home TVs, computers, mobile phone chargers, and more and more home appliances use switching power supply technology to rectify AC power into DC and then supply power (see Figure 3), so it is completely possible to pass through in off-grid photovoltaic systems. DC power supply to realize the normal operation of household appliances.

Inverter-type home appliances use inverter-related technologies to control the frequency of DC motors, and the input power supply also uses one-way or three-phase rectifier bridge technology to rectify AC into DC, and then work (see Figure 4 shown), therefore, household electrical power supply can also be realized through DC power supply.

Since high-frequency off-grid inverters generally adopt a voltage-type control mode, a large capacitor is required on the main DC bus to provide energy, and the loss of the high-voltage bridge inverter switching tubes on the DC bus has always limited the efficiency of the inverter. major factor. If the power consumption of the inverter itself is considered, this will be a large loss.

Therefore, it is necessary to provide an improved photovoltaic DC off-grid system to solve the above problems.

Utility model content

The purpose of the utility model is to provide a photovoltaic DC off-grid system that can realize high and low voltage separate and direct power supply, and can improve the utilization rate of photovoltaic power generation and reduce costs.

In order to achieve the aforementioned purpose, the utility model adopts the following technical solution: a photovoltaic DC off-grid system, including a photovoltaic cell array, a photovoltaic controller connected to the photovoltaic cell array, a storage battery connected to the photovoltaic controller, and A low-voltage conversion circuit connected with the photovoltaic controller for outputting a low-voltage DC voltage and a high-voltage booster circuit for outputting a high-voltage DC voltage.

As a further improvement of the present invention, the high-voltage boost circuit includes a push-pull boost circuit connected to the photovoltaic controller, and a full-bridge rectifier circuit connected to the push-pull boost circuit.

As a further improvement of the present utility model, the high-voltage boost circuit includes a full-bridge boost circuit connected to the photovoltaic controller, and a full-bridge rectifier circuit connected to the full-bridge boost circuit.

As a further improvement of the utility model, the photovoltaic controller is an MPPT controller.

The beneficial effects of the utility model are: the photovoltaic DC off-grid system of the utility model is directly connected behind the photovoltaic controller to respectively realize the low-voltage conversion circuit and the high-voltage boost circuit that output the low-voltage DC voltage and the high-voltage DC voltage, thereby realizing high and low voltage Separate and direct power supply simplifies the procedure of power conversion, thereby helping to improve the utilization rate of photovoltaic power generation and reduce costs.

Description of drawings

Fig. 1 is a structural block diagram of a photovoltaic AC off-grid system in the prior art.

Fig. 2 is a structural block diagram of a photovoltaic DC off-grid system in the prior art.

Fig. 3 is a diagram of a switching power supply in the prior art.

Fig. 4 is a circuit diagram of a frequency converter in the prior art.

Fig. 5 is a structural block diagram of the photovoltaic DC off-grid system of the present invention.

FIG. 6 is a schematic structural diagram of a preferred embodiment of the photovoltaic DC off-grid system in FIG. 5 .

Fig. 7 is a schematic structural diagram of another preferred embodiment of the photovoltaic DC off-grid system in Fig. 5 .

Detailed ways

Please refer to FIG. 5 , the photovoltaic DC off-grid system in an embodiment of the present invention includes a photovoltaic cell array 1 , a photovoltaic controller 2 , a storage battery 3 , a low-voltage conversion circuit 4 , and a high-voltage booster circuit 5 .

Photovoltaic controller 2 is an MPPT (Maximum Power Point Tracking, MPPT for short) controller. The photovoltaic controller 2 controls the charging and discharging of the storage battery 3 , and can output two DC voltages respectively, one DC voltage is output to the low-voltage conversion circuit 4 , and the other DC voltage is output to the high-voltage boosting circuit 5 . The photovoltaic controller 2 is respectively connected with the photovoltaic cell array 1 , the storage battery 3 , the low voltage conversion circuit 4 and the high voltage boost circuit 5 . In this embodiment, since the photovoltaic controller 2 adopts an MPPT controller, the maximum energy storage of solar energy conversion can be realized.

The low-voltage conversion circuit 4 receives one of the DC voltages output by the photovoltaic controller 2 and outputs a low-voltage DC voltage, and the output low-voltage DC voltage is lower than the safe working voltage, wherein the safe working voltage is 36V. The low-voltage DC voltage output by the low-voltage conversion circuit 4 is used by low-power loads 62, such as LEDs and CFLs. The low-voltage conversion circuit 4 can adopt a Boost circuit or a Buck circuit.

The high-voltage boost circuit 5 receives another DC voltage output by the photovoltaic controller 2 and outputs a high-voltage DC voltage. The high-voltage DC voltage output by it is higher than the safe working voltage, generally around 300V, so as to ensure that it can be used by a high-power load 61, such as household TV, computer, etc.

Please refer to Fig. 6, wherein in one embodiment, the high-voltage booster circuit 5 includes a push-pull booster circuit 51 connected to the photovoltaic controller 2 and receiving the DC circuit of the photovoltaic controller 2, and a push-pull booster circuit 51 Connect and output a full-bridge rectifier circuit 52 with a voltage above 310V. The high-voltage boost circuit 5 realizes DC-DC boost conversion to raise the voltage of the storage battery 3 to DC 310V, so as to ensure a peak voltage of AC 220V greater than the demand of the high-power load 61 .

Please refer to Fig. 7, another above-mentioned high-voltage boost circuit 5 can also be realized by the following circuit: the high-voltage boost circuit 5 includes a full-bridge boost circuit 53 connected with the photovoltaic controller 2 and outputting a voltage above 310V, and a full-bridge The bridge boost circuit 53 is connected to the full bridge rectifier circuit 54 . The high-voltage boost circuit 5 realizes DC-DC boost conversion to raise the voltage of the storage battery 3 to DC 310V, so as to ensure a peak voltage of AC 220V that is much greater than the demand of the power load 61 .

To sum up, the above-mentioned photovoltaic DC off-grid system is directly connected behind the photovoltaic controller 2 to realize the low-voltage conversion circuit 4 and the high-voltage boost circuit 5 that output low-voltage DC voltage and high-voltage DC voltage respectively, so as to realize separate direct power supply for high and low voltage. , which simplifies the procedure of power conversion, thereby helping to improve the utilization rate of photovoltaic power generation and reduce the cost.

Although preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that, without departing from the scope and spirit of the present invention as disclosed by the appended claims, Various improvements, additions, and substitutions are possible.

Claims (4)

1. a photovoltaic DC is from the net system, comprise photovoltaic battery array, the photovoltaic controller that is connected with described photovoltaic battery array and the storage battery that is connected with described photovoltaic controller, it is characterized in that: described photovoltaic DC also comprises from the net system and being connected with described photovoltaic controller respectively and in order to the low voltage conversion circuit of exporting low-voltage dc voltage with in order to export the high voltage step-up circuit of high-voltage dc voltage.

2. photovoltaic DC according to claim 1 is characterized in that from the net system: described high voltage step-up circuit comprises the push-pull type booster circuit that is connected with described photovoltaic controller, the full bridge rectifier that is connected with described push-pull type booster circuit.

3. photovoltaic DC according to claim 1 is characterized in that from the net system: described high voltage step-up circuit comprises the full-bridge boost circuit that is connected with described photovoltaic controller, the full bridge rectifier that is connected with described full-bridge boost circuit.

According to claim 2 or 3 described photovoltaic DCs from the net system, it is characterized in that: described photovoltaic controller is the MPPT controller.

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