CN212163185U

CN212163185U - Transformer-free single-phase three-wire inverter device

Info

Publication number: CN212163185U
Application number: CN202020852085.7U
Authority: CN
Inventors: 耿向真
Original assignee: Qingdao Nengfeng Electric Co ltd
Current assignee: Qingdao Nengfeng Electric Co ltd
Priority date: 2020-02-29
Filing date: 2020-05-20
Publication date: 2020-12-15
Anticipated expiration: 2030-05-20

Abstract

The utility model discloses a single-phase three-wire inverter device of no transformer, including direct current voltage stabilizing module, contravariant unit and central line transform unit, wherein, direct current voltage stabilizing module contravariant unit and central line transform unit parallel connection. Adopt the utility model discloses an inverter device need not the transformer and can realize single-phase three-wire type output, for current product, has greatly reduced weight volume and cost.

Description

Transformer-free single-phase three-wire inverter device

Technical Field

The utility model relates to an inverter power supply device field particularly, relates to a single-phase three-wire inverter device of no transformer.

Background

With the shortage of petrochemical energy, the obvious environmental and climate change problems, the use of renewable energy is increasingly gaining attention, photovoltaic power generation is an important component of renewable energy, and an inverter power supply device is an important device in a photovoltaic power generation system. With the gradual maturity of the technology, the conversion efficiency of the solar cell panel is continuously improved, the power electronic devices and the control technology are continuously updated and upgraded, and the utilization of the photovoltaic inverter power supply device is greatly improved due to the improvement of the energy storage battery technology.

The inverter power supply device commonly used in the field of photovoltaic grid connection and disconnection at present is generally single-phase double-wire output, and when the inverter power supply device is used in a disconnection mode, the inverter power supply device cannot be suitable for a scene requiring single-phase three-wire output. In contrast, in the inverter power supply apparatus having a single-phase three-wire output, the formation of the single-phase three-wire output depends on a transformer having a center tap, which causes an increase in cost and an increase in volume and weight of the apparatus.

SUMMERY OF THE UTILITY MODEL

The utility model discloses it is with high costs to aim at solving the contravariant power supply device of current single-phase three-wire type output, and is bulky, heavy problem.

In order to solve the technical problem, the utility model provides a single-phase three-wire inverter device of no transformer, including direct current voltage stabilizing module, contravariant unit and central line transform unit, wherein, direct current voltage stabilizing module contravariant unit and central line transform unit parallel connection.

According to the utility model discloses a preferred embodiment, direct current voltage stabilizing module is boost type DCDC, and its input is connected with direct current input, and output and contravariant unit and central line transform unit are connected.

According to a preferred embodiment of the present invention, the dc regulator module has an inductive winding P1 switching tube Q3 and a diode D2.

According to the utility model discloses a preferred embodiment, the contravariant unit is bridge type converting circuit, its input with direct current voltage stabilizing module connects, and the output is first output and second output.

According to a preferred embodiment of the present invention, the inverter unit is formed by bridging four switching devices Q1, Q2, Q6 and Q7.

According to the utility model discloses a preferred embodiment, the central line transform unit is switch circuit, the input with direct current voltage stabilizing module connects, and the output is the third output.

According to a preferred embodiment of the present invention, the neutral line transformation unit comprises a set of switching tubes Q31 and Q32 connected in series.

According to the present invention, the first output end and the second output end of the inversion unit and the third output end of the neutral line transformation unit constitute a single-phase three-wire output.

According to the utility model discloses a preferred embodiment, the device still includes the wave filter, the input with contravariant unit and the output of central line transform unit is connected.

According to a preferred embodiment of the present invention, the filter is formed by electrical coils L1, L2 and L3.

Adopt the utility model discloses an inverter device need not the transformer and can realize single-phase three-wire type output, for current product, has greatly reduced weight volume and cost.

Drawings

In order to make the technical problem solved by the present invention, the technical means adopted by the present invention, and the technical effects obtained by the technical means clearer, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted, however, that the drawings described below are only drawings of exemplary embodiments of the invention, from which other embodiments can be derived by those skilled in the art without inventive effort.

Fig. 1 is a block diagram of a single-phase three-wire inverter apparatus without a transformer according to an embodiment of the present invention;

fig. 2 is a specific circuit diagram of a single-phase three-wire inverter device without transformer according to an embodiment of the present invention;

fig. 3 is a timing diagram illustrating operations of the inverter unit and the neutral line transformer unit according to an embodiment of the present invention.

Detailed Description

Exemplary embodiments of the present invention will now be described more fully with reference to the accompanying drawings, in which exemplary embodiments can be implemented in a number of specific ways, which should not be construed as limiting the invention to the embodiments set forth herein. Rather, these exemplary embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art.

The structures, properties, effects or other features described in a particular embodiment can be combined in any suitable manner in one or more other embodiments, consistent with the technical idea of the invention.

In describing particular embodiments, specific details of structures, properties, effects, or other features are set forth in order to provide a thorough understanding of the embodiments by one skilled in the art. However, it is not excluded that a person skilled in the art may implement the invention in a specific case in a solution that does not contain the above-described structures, properties, effects or other features.

The same reference numerals denote the same or similar elements, components, or parts throughout the drawings, and thus, a repetitive description thereof may be omitted hereinafter. It will be further understood that, although the terms first, second, third, etc. may be used herein to describe various elements, components, or sections, these elements, components, or sections should not be limited by these terms. That is, these phrases are used only to distinguish one from another. For example, a first device may also be referred to as a second device without departing from the spirit of the present invention. Furthermore, the term "and/or", "and/or" is intended to include all combinations of any one or more of the listed items.

Fig. 1 is a block diagram of a single-phase three-wire inverter device without transformer, as shown in fig. 1, the device includes a dc voltage stabilizing module 1, an inverter unit 2 and a neutral line transformation unit 3, wherein the dc voltage stabilizing module 1, the inverter unit 2 and the neutral line transformation unit 3 are connected in parallel. The dc voltage stabilizing module 1 is a boost DCDC, and adjusts the power supply side voltage into a stable bus voltage, and provides the stable bus voltage to the inverter unit 2 and the neutral line converter unit 3. The inverter unit 2 includes a first output terminal a and a second output terminal B, and converts the dc voltage output of the dc voltage stabilizing module 1 into a desired ac power and outputs the ac power. The neutral line transformation unit 3 is formed by connecting 2 switching devices in series, and comprises a third output end O for forming a median voltage of the dc bus voltage output from the dc voltage stabilizing module 1. A single-phase three-wire output can be taken out from the first output terminal a, the second output terminal B of the inverter unit 2 and the third output terminal O of the neutral line transformation unit 3, e.g., AC110V can be taken out from between the output terminal a and the output terminal O and between the output terminal B and the output terminal O, and AC220V can be taken out from between the output terminal a and the output terminal B.

Fig. 2 is a specific circuit diagram of a single-phase three-wire inverter apparatus without a transformer, and as shown in fig. 2, the dc voltage stabilizing module 1 has a switching tube Q3 and a diode D2 with an inductive winding P1. When the switching tube Q3 is turned on, the inductive winding P stores energy, and the stored energy is discharged when the switching tube Q3 is turned off, thereby realizing the boost DCDC function. The dc bus voltage output by the dc regulator module 1 is adjusted by PWM modulation of the switching tube Q3.

The inverter unit 2 is bridged by four switching devices Q1, Q2, Q6, and Q7, and can alternately turn on and off a circuit composed of Q1 and Q6 and a circuit composed of Q2 and Q7 as in a known method.

And a neutral line transformation unit 3 for forming a midpoint of the dc voltage output from the dc voltage stabilization module 1. The neutral line transformation unit 3 is composed of a group of switching tubes Q31 and Q32 connected in series, and an output line is led out from the connection point of the two for forming a median voltage point. When Q31 and Q32 are alternately driven to be on at a duty ratio of 50%, the output median voltage is half of the output voltage of the dc regulator module 1, i.e., the midpoint of the input voltage of the inverter unit.

The filter 4 is formed by electrical coils L1, L2 and L3, and is connected to the first output terminal and the second output terminal of the inverter 2 and the third output terminal of the neutral line transforming unit 3. The filter 4 can smooth the output of the inverter 2 and the neutral-line transformation unit 3 and make the output end thereof constitute a single-phase three-line type output.

Fig. 3 is an operation timing chart of the inverter unit and the neutral line converter unit, and as shown in fig. 3 (a) and (B), when the circuit composed of Q1 and Q7 and the circuit composed of Q2 and Q6 of the inverter unit 2 are alternately turned on and off and PWM modulation is performed when the circuits are turned on, the AC voltage AC220V shown in fig. 3(E) can be output to the output terminal of the inverter unit 2. As shown in fig. 3(C) and (D), if Q31 and Q32 of the neutral line transformation unit 3 are alternately turned on and off at a duty ratio of 50%, the voltage output from the output terminal of the neutral line transformation unit 3 can be the midpoint between the input terminal and the output terminal of the inverter unit 2, the output terminal of the inverter unit 2 and the output terminal of the neutral line transformation unit 3 form a single-phase three-wire output, for example, AC110V is output between the output terminal a and the output terminal O and between the output terminal B and the output terminal O, and AC220V is output between the output terminal a and the output terminal B.

Those of skill in the art would appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention. It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.

In the embodiments disclosed herein, it should be understood that the disclosed methods, articles of manufacture (including but not limited to devices, apparatuses, etc.) may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form. The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment. In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit.

Claims

1. The single-phase three-wire inverter device without the transformer is characterized by comprising a direct-current voltage stabilizing module, an inversion unit and a neutral wire conversion unit, wherein the direct-current voltage stabilizing module, the inversion unit and the neutral wire conversion unit are connected in parallel.

2. The single-phase three-wire inverter apparatus of claim 1, wherein the dc voltage stabilization module is a boost DCDC, and an input of the dc voltage stabilization module is connected to the dc input, and an output of the dc voltage stabilization module is connected to the inverter unit and the neutral line conversion unit.

3. The single-phase three-wire inverter apparatus of claim 2, wherein the dc voltage stabilization module has an inductive winding P1, a switching tube Q3 and a diode D2.

4. The single-phase three-wire inverter apparatus of claim 1, wherein the inverter unit is a bridge inverter circuit having an input connected to the dc voltage stabilization module and an output having a first output terminal and a second output terminal.

5. The single-phase three-wire inverter apparatus of claim 4, wherein the inverter unit is bridge-connected by four switching devices Q1, Q2, Q6 and Q7.

6. The single-phase three-wire inverter apparatus of claim 4, wherein the neutral line conversion unit is a switching circuit, an input is connected to the DC voltage stabilization module, and an output is a third output terminal.

7. The single-phase three-wire inverter apparatus of claim 6, wherein the neutral line transformation unit is composed of a set of switching tubes Q31 and Q32 connected in series.

8. The single-phase three-wire inverter apparatus of claim 6, wherein the first output terminal, the second output terminal of the inverting unit and the third output terminal of the neutral line transforming unit constitute a single-phase three-wire output.

9. The single-phase three-wire inverter device according to any one of claims 1 to 8, further comprising a filter having an input connected to the output of the inverter unit and the neutral-line transformation unit.

10. The single-phase three-wire inverter apparatus of claim 9, wherein the filter is composed of electric coils L1, L2, and L3.