CN202535293U - Output device of three-phase photovoltaic inverter - Google Patents

Abstract

The utility model relates to an output device of a three-phase photovoltaic inverter, comprising at least two capacitors connected in parallel, at least two three-phase full-bridge inverter modules, at least two reactors and filter capacitors; the at least two capacitors Connected in parallel between the two poles of the external DC power supply, the at least two parallel capacitors are respectively connected to at least two three-phase full-bridge inverter modules; the at least two three-phase full-bridge inverter modules are connected in parallel with each other, and the The output terminals of the at least two three-phase full-bridge inverter modules are respectively connected to at least two reactors; the at least two reactors are connected in parallel, filtered by a filter capacitor, and then connected to the output terminals. The utility model has the advantages of simple structure, low cost and easy realization; the technology is reliable and can run stably for a long time; the problem of unbalanced current of IGBTs connected in parallel of each phase in the direct parallel application process of IGBTs is solved, so that the photovoltaic power generation system can be kept in a safe and stable state for a long time Grid-connected power generation.

Description

An output device of a three-phase photovoltaic inverter

technical field

The utility model relates to an output device, in particular to an output device of a three-phase photovoltaic inverter, which belongs to the field of photovoltaic power generation.

Background technique

Photovoltaic grid-connected power generation system is a development trend in the field of new energy applications at present. Its biggest advantage is that it does not need battery energy storage. Photovoltaic grid-connected inverter is the core part of the whole system. At present, photovoltaic grid-connected inverters from several KW to hundreds of KW have been widely used in photovoltaic grid-connected power generation systems. In recent years, the photovoltaic power generation industry has developed rapidly, and it is urgent for manufacturers in the photovoltaic industry to design and produce larger inverters. Photovoltaic grid-connected inverter of power level. Due to the limitation of the manufacturing process of IGBT power electronic devices, the current design of high-power grid-connected inverters mostly adopts the method of direct parallel connection of IGBTs to increase the current level of the inverter, and then increase the power level of the inverter.

At present, in the three-phase full-bridge inverter process of the photovoltaic inverter, the direct parallel connection of IGBTs is mainly used to meet the requirements of increasing the output power of the inverter: the advantage is that the circuit structure is simple; the disadvantage is that due to the characteristics of the drive circuit, The influence of device characteristics and circuit layout will cause the unbalanced current flowing through the parallel IGBTs in each phase, and the devices will be easily damaged due to overcurrent and overheating.

Utility model content

The utility model provides a simple, practical, stable, reliable and low-cost output device of a three-phase photovoltaic inverter aiming at the disadvantages of the prior art that devices are easily damaged. 

The technical scheme of the utility model for solving the above-mentioned technical problems is as follows: an output device of a three-phase photovoltaic inverter, including at least two capacitors connected in parallel, at least two three-phase full-bridge inverter modules, at least two reactors and filter capacitance;

The at least two capacitors are connected in parallel between the poles of the external DC power supply, the at least two parallel capacitors are respectively connected to at least two three-phase full-bridge inverter modules, and the parallel capacitors filter the input DC power;

The at least two three-phase full-bridge inverter modules are connected in parallel, and the output terminals of the at least two three-phase full-bridge inverter modules are respectively connected to at least two reactors, and the at least two three-phase full-bridge inverter modules The inverter module converts the input direct current into alternating current;

The at least two reactors are connected in parallel and connected to the output terminal after being filtered by a filter capacitor, and the reactors convert the input alternating current into sinusoidal voltage and sinusoidal current.

The beneficial effects of the utility model are: the utility model is simple in structure, low in cost, easy to implement; reliable in technology, and can run stably for a long time; solves the current imbalance problem of parallel IGBTs in each phase of the IGBT direct parallel application process, making the photovoltaic power generation system Maintain grid-connected power generation in a safe and stable state for a long time.

On the basis of the above technical solutions, the utility model can also be improved as follows.

Further, the two output terminals of the at least two capacitors connected in parallel are respectively connected to the two input terminals of each three-phase full-bridge inverter module in the at least two three-phase full-bridge inverter modules.

Further, the reactor is a three-phase reactor, and the three input terminals of the three-phase reactor are respectively connected with the three output terminals of the three-phase full-bridge inverter module, and the at least two three-phase reactors The three input terminals are respectively connected in parallel and then connected with three filter capacitors.

Further, the three-phase full-bridge inverter module includes six absorbing capacitors and three double-tube IGBT modules connected in parallel, each of the double-tube IGBT modules is connected to two absorbing capacitors, and each of the double-tube IGBT modules The module has one output terminal, and the three output terminals of the three double-tube IGBT modules form the three output terminals of the three-phase full-bridge inverter module.

Further, the dual-tube IGBT module includes two interconnected IGBT modules, and each IGBT module is connected in parallel with a snubber capacitor.

Further, the output device of the three-phase photovoltaic inverter also includes at least two positive copper bus bars and at least two negative copper bus bars, and the parallel capacitor and the dual-tube IGBT module are connected in parallel between the positive copper bus bars and the negative electrodes. Between the copper busbars.

Further, the at least two capacitors connected in parallel are all large-capacity capacitors.

Description of drawings

Fig. 1 is a circuit diagram of the output device of the three-phase photovoltaic inverter described in the present invention.

Detailed ways

The principles and features of the present utility model are described below in conjunction with the accompanying drawings, and the examples given are only used to explain the utility model, and are not used to limit the scope of the utility model.

As shown in Figure 1, the output device of a three-phase photovoltaic inverter described in Embodiment 1 of the present utility model includes fifty-four parallel-connected 520UF/900V capacitors 1, two three-phase full-bridge inverter modules 2 , two 550A/0.35mH three-phase reactors 3 and AC filter capacitor 4;

The fifty-four capacitors 1 are connected in parallel between the poles of the external DC power supply, and the parallel capacitors 1 are respectively connected to two three-phase full-bridge inverter modules 2, and the parallel capacitors 1 filter the input DC power;

The two three-phase full-bridge inverter modules 2 are connected in parallel, and the output terminals of the two three-phase full-bridge inverter modules 2 are respectively connected to two reactors 3, and the two three-phase full-bridge inverter modules Module 2 converts the input direct current into alternating current;

The two reactors 3 are connected in parallel and then filtered by the filter capacitor 4 and then connected to the output terminal. The reactor 3 converts the input alternating current into a sine wave voltage and a sine wave current.

The two output terminals of the fifty-four parallel capacitors 1 are respectively connected to the two input terminals of each three-phase full-bridge inverter module 2 in the two three-phase full-bridge inverter modules 2 .

The three input terminals of the three-phase reactor 3 are respectively connected with the three output terminals of the three-phase full-bridge inverter module 2, and the three input terminals of the two three-phase reactors 3 are respectively connected in parallel with three The filter capacitor is connected to 4 phases.

The three-phase full-bridge inverter module 2 includes three 1400A/1200V dual-tube IGBT modules 21 in which six absorption capacitors 22 are connected in parallel, and each double-tube IGBT module 21 is connected to two absorption capacitors 22, and has One output terminal, the three output terminals of the three dual-tube IGBT modules 21 constitute the three output terminals of the three-phase full-bridge inverter module 2 .

The dual-tube IGBT module 21 includes two interconnected IGBT modules, and each IGBT module is connected in parallel with a snubber capacitor 22 .

The output device of the three-phase photovoltaic inverter also includes two positive copper bus bars 5 and two negative copper bus bars 6, and the parallel capacitor 1 and the double-tube IGBT module 21 are connected in parallel between the positive copper bus bars 5 and the two negative copper bus bars 6. between the negative copper bus bars 6 .

When this embodiment is used specifically, the DC power supply is provided by the photovoltaic cell, and the voltage of the photovoltaic cell is sent to both ends of the DC large-capacity capacitor 1 and the positive and negative copper busbars 5 and 6 through the DC filter; the DC voltage is passed through the three-phase full-bridge inverter Transforming module 2 converts the AC voltage into the reactor 3, and the output of the reactor 3 is connected in parallel and then intervened in the AC output filter capacitor 4, finally obtaining pure sine wave AC voltage and high power level sine wave current.

The above descriptions are only preferred embodiments of the present utility model, and are not intended to limit the present utility model. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present utility model shall be included in this utility model. within the scope of protection of utility models.

Claims (7)

1. the output device of a three-phase photovoltaic DC-to-AC converter is characterized in that, comprises the electric capacity of at least two parallel connections, at least two three phase full bridge inversion modules, at least two reactors and filter capacitor;

Said at least two electric capacity are parallel between the two poles of the earth of external dc power, and said at least two shunt capacitances are connected with at least two three phase full bridge inversion modules respectively, and said shunt capacitance carries out filtering with the direct current of input;

Said at least two three phase full bridge inversion modules are parallel with one another; And the output of said at least two three phase full bridge inversion modules is connected with at least two reactors respectively, and said at least two three phase full bridge inversion modules convert the direct current of input into alternating current;

Through being connected with output after the filter capacitor filtering, said reactor converts the alternating current of input into sine voltage and sine-wave current after said at least two reactor parallel connections.

2. output device according to claim 1 is characterized in that, two outputs of the electric capacity of said at least two parallel connections respectively with at least two three phase full bridge inversion modules in two inputs of each three phase full bridge inversion module be connected.

3. output device according to claim 1; It is characterized in that; Said reactor is a three-phase reactor; Three inputs of said three-phase reactor are connected with three outputs of three phase full bridge inversion module respectively, and three inputs of said at least two three-phase reactors are connected with three filter capacitors the parallel connection back respectively.

4. output device according to claim 1; It is characterized in that; Said three phase full bridge inversion module comprises that six absorb electric capacity and three two-tube IGBT modules parallel with one another; Said each two-tube IGBT module is connected with two absorption electric capacity, and said each two-tube IGBT module has an output, and three outputs of said three two-tube IGBT modules are formed three outputs of three phase full bridge inversion modules.

5. output device according to claim 4 is characterized in that, said two-tube IGBT module comprises two interconnective IGBT modules, and said each IGBT module is parallelly connected with an absorption electric capacity.

6. according to each described output device of claim 1 to 5; It is characterized in that; The output device of said a kind of three-phase photovoltaic DC-to-AC converter also comprises at least two anodal copper bus-bars and at least two negative pole copper bus-bars, and said shunt capacitance and two-tube IGBT module are connected in parallel between anodal copper bus-bar and the negative pole copper bus-bar.

7. output device according to claim 6 is characterized in that, the electric capacity of said at least two parallel connections is large bulk capacitance entirely.

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