WO2016004896A1

WO2016004896A1 - Photovoltaic inverter and air conditioner

Info

Publication number: WO2016004896A1
Application number: PCT/CN2015/083782
Authority: WO
Inventors: 马鑫; 卓森庆; 游剑波; 张嘉鑫; 李发顺
Original assignee: 珠海格力电器股份有限公司
Priority date: 2014-07-11
Filing date: 2015-07-10
Publication date: 2016-01-14
Also published as: CN104135225A

Abstract

Provided is a photovoltaic inverter, comprising a basic photovoltaic inverter unit. The basic photovoltaic inverter unit comprises a photovoltaic battery assembly, a DC-DC voltage booster, a first switching switch, a grid-connected inverter, and a grid-connected filter; the photovoltaic battery assembly, the DC-DC voltage booster, the grid-connected inverter, the grid-connected filter, and an alternating current grid are electrically connected in sequence; the first switching switch comprises one first input terminal and two output terminals; the two output terminals are the first output terminal and the second output terminal; the input terminal of the first switching switch is connected to the output terminal of the DC-DC voltage booster; the first output terminal of the first switching switch is connected to the input terminal of the grid-connected inverter for outputting the alternating current into the grid; the second output of the first switching switch serves as a direct current bus terminal for outputting the direct current. The present invention also relates to an air conditioner. The photovoltaic inverter and the air conditioner of the present invention enhance the utilization rate of the electricity generated by the photovoltaic battery assembly.

Description

Photovoltaic inverters and air conditioners

Related application

This patent application claims priority to the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the disclosure.

Technical field

The present invention relates to the field of photovoltaic technology, and in particular to a photovoltaic inverter and an air conditioner.

Background technique

The general household photovoltaic inverters are connected to the grid to output alternating current, and for household appliances such as air conditioners, refrigerators, washing machines, etc., which need to use AC-DC-AC conversion to drive the motor, the DC power generated by the photovoltaic cells is inverted and rectified. After that, it becomes DC power, and the utilization efficiency of the electric energy generated by the photovoltaic photovoltaic cell module is low.

Summary of the invention

In view of the current state of the art, the object of the present invention is to provide a photovoltaic inverter and an air conditioner, so that the electric energy generated by the photovoltaic cell assembly can be used as a direct current output or an alternating current into an alternating current grid, thereby improving the photovoltaic module. The efficiency of utilization of the generated electrical energy.

To achieve the above object, the present invention adopts the following technical solutions:

A photovoltaic inverter comprising a basic photovoltaic inverter unit;

The basic photovoltaic inverter unit includes a photovoltaic cell assembly, a DC-DC booster, a first switch, a grid-tied inverter, and a grid-connected filter; the photovoltaic cell assembly, the DC-DC booster The grid-connected inverter, the grid-connected filter and the alternating current grid are electrically connected in sequence;

The first switch includes an input end and two output ends, and the two output ends are respectively a first output end and a second output end, and an input end of the first switch switch is connected to the DC-DC liter The first output end of the first switch is connected to the input end of the grid-connected inverter for outputting alternating current; the second output of the first switch is used as a DC bus Port for outputting DC power.

In one embodiment, the basic photovoltaic inverter unit further includes a capacitor connected between an output of the DC-DC booster and an input of the first changeover switch, Capacitors are used for voltage regulation.

In one embodiment, the grid-connected filter is an EMC filter for filtering harmonics of the output current of the grid-connected inverter.

In one embodiment, the number of the basic photovoltaic inverter units is N, and the N basic photovoltaic inverters are connected in parallel through the second output end of the first switching switch; the basic photovoltaic inverter The number of units is N ≥ 2.

In one of the embodiments, the basic photovoltaic inverter unit further includes a communication module for data communication between the N basic photovoltaic inverter units.

In one of the embodiments, the communication modules of the N said substantially photovoltaic inverter units are connected by a communication cable.

In one of the embodiments, the number of the communication cables is N-1.

In one embodiment, the photovoltaic inverter further includes a controller for controlling an input end of the first switch and a first output and/or a second of the first switch The output is connected.

The present invention also relates to an air conditioner comprising the photovoltaic inverter of any of the above;

a second switch, a compressor inverter, a power factor corrector, a rectifier, an EMC filter, and a third switch; the AC power grid sequentially passes through the third switch, the EMC filter, the rectifier, The power factor corrector and the compressor inverter are connected to a compressor, and a DC bus port is sequentially connected to the compressor through the second changeover switch and a compressor inverter.

In one of the embodiments, the air conditioner further includes an air conditioning communication module for data communication between the air conditioner and the photovoltaic inverter.

The beneficial effects of the invention are:

The photovoltaic inverter and the air conditioner of the present invention, by providing a first switch between the DC-DC booster and the grid-connected inverter, so that the photovoltaic inverter can pass through the second output of the first switch The output DC power can also be connected to the first output end of the first switch to output AC power. By controlling the working state of the first switch, the AC-DC-AC switch can be realized, and the household appliances such as the air conditioner and the washing machine are satisfied. The driving requirements increase the utilization efficiency of the electric energy generated by the photovoltaic cell module.

DRAWINGS

1 is a schematic diagram of an embodiment of a basic photovoltaic inverter unit of a photovoltaic inverter of the present invention;

2 is a schematic diagram of a plurality of basic photovoltaic inverter units of a photovoltaic inverter of the present invention in parallel;

Fig. 3 is a schematic view showing an embodiment of an air conditioner of the present invention.

detailed description

In order to make the technical solution of the present invention clearer, the photovoltaic inverter and the air conditioner of the present invention will be further described in detail below with reference to the accompanying drawings. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Referring to FIG. 1 and FIG. 3, as shown in FIG. 1, the photovoltaic inverter of the present invention comprises a basic photovoltaic inverter unit, and the basic photovoltaic inverter unit comprises a photovoltaic cell component 1, a DC-DC booster 2, and a capacitor 3. The communication module 4, the first changeover switch 5, the grid-connected inverter 6, and the grid-connected filter 7. The photovoltaic cell component 1, the DC-DC booster 2, the grid-connected inverter 6, the grid-connected filter 7, and the AC grid 8 are electrically connected in sequence. The photovoltaic cell module 1 is used to convert solar energy into electrical energy and output low voltage direct current. The DC-DC booster 2 is used to convert the low-voltage direct current generated by the photovoltaic cell module 1 into high-voltage direct current, so that the low-voltage direct current generated by the photovoltaic cell assembly is raised to a high voltage required by the grid-connected inverter.

The first switch 5 is disposed between the DC-DC booster 2 and the grid-connected inverter 6. The first switch 5 includes an input terminal and two output terminals, and the two output terminals are respectively a first output terminal and Second output. The input end of the first changeover switch 5 is connected to the output end of the DC-DC booster 2. The first output end of the first changeover switch 5 is connected to the input end of the grid-connected inverter 6, and is used for grid-connecting output of alternating current. In this way, the high-voltage direct current outputted by the DC-DC booster 2 enters the grid-connected inverter 6 through the first switch 5, and the grid-connected inverter 6 is used to convert the high-voltage direct current into alternating current, and then passes through the grid-connected filter 7. After filtering, it is connected to the AC grid 8, and the DC power generated by the PV module 1 is integrated into the AC grid.

The second output end of the first changeover switch 5 serves as a DC bus port for outputting direct current, so that the high voltage direct current output from the DC-DC booster 2 directly outputs direct current through the first changeover switch 5. In actual use, the second output end of the first switch 5 can be directly connected to the DC-AC converter of the household appliance or the DC primary of the DC-DC converter, so that the conversion of the electric energy is reduced and the number of the electric energy is reduced. The efficiency of utilization of electrical energy generated by photovoltaic cells.

The general photovoltaic inverter directly outputs the alternating current through the grid-connected inverter, and then the alternating current output from the alternating current grid is inverted, rectified and filtered, and then output the direct current and then connected to the DC-AC converter of the household appliance or DC-DC converter. The DC primary of the device leads to more transformation of the electric energy, and the utilization efficiency of the electric energy generated by the photovoltaic cell is low. The photovoltaic inverter of the invention directly outputs direct current only after passing through the first-stage DC-DC booster, thereby improving the utilization efficiency of the electric energy generated by the photovoltaic cell assembly.

The first switching switch is arranged between the DC-DC booster and the grid-connected inverter, so that the photovoltaic inverter can output direct current through the second output end of the first switching switch, or can pass the first switching switch. The first output is connected to the grid AC power, by controlling the working state of the first switch, realizes the switching between AC-DC-AC, satisfies the driving requirements of household appliances such as air conditioners and washing machines, and improves the utilization efficiency of the electric energy generated by the photovoltaic cells.

As an implementation, the capacitor 3 is connected between the output of the DC-DC booster 2 and the input of the first changeover switch 5, and the capacitor 3 is used for voltage regulation. The high-voltage direct current outputted by the DC-DC booster 2 is regulated by the capacitor 3 and sent to the input end of the first changeover switch 5, thereby preventing voltage fluctuations from causing damage to the household appliances and the grid-connected inverter, and ensuring the household appliances. And the normal operation of electrical equipment such as grid-connected inverters.

Preferably, the grid-connected filter 7 is an EMC filter for filtering harmonics of the output current of the grid-connected inverter 6. EMC (Electromagnetic Compatibility) refers to the ability of a device or system to operate as required in its electromagnetic environment without electromagnetic interference to any equipment in its environment. Since there is a certain requirement for the current of the grid-connected inverter input AC grid, it is necessary to reduce the harmonic of the output current of the grid-connected inverter 6 through the grid-connected filter 7, so that the current output by the grid-connected inverter Meet the requirements of grid connection.

As shown in FIG. 2, as an implementable manner, the number of basic photovoltaic inverter units is N, and the N basic photovoltaic inverters are arranged in parallel through the second output end of the first changeover switch 5, that is, N. The basic PV inverters are arranged in parallel via the DC bus ports. In the present embodiment, the number of basic photovoltaic inverter units is N ≥ 2, and N is an integer.

When the load power requiring DC power supply is increased, the DC bus ports of the basic photovoltaic inverter unit can be connected in parallel, that is, the second output terminals of the first switching switch 5 of the basic photovoltaic inverter unit are connected in parallel. At this time, the photovoltaic cell assemblies 1 in the respective basic photovoltaic inverter units may be identical, or different models may be selected according to actual needs.

Preferably, the communication modules 4 of the N basic photovoltaic inverter units are connected by a communication cable, and the communication module 4 is used for data communication between N basic photovoltaic inverter units to realize N parallel basic photovoltaic inverters. Collaborative work between units. Preferably, the number of communication cables is N-1, and the N-1 communication cables form a communication cable loop for communication between the respective basic photovoltaic inverters, where N refers to the number of basic photovoltaic inverter units. In other embodiments, data communication can be performed between the N communication modules by means of wireless communication such as Bluetooth or ZigBee.

Preferably, the photovoltaic inverter further comprises a controller for controlling the input of the first changeover switch 5 to communicate with the first output and/or the second output of the first changeover switch 5. When the controller controls the input end of the first switch 5 to communicate with the first output of the first switch 5, the photovoltaic inverter only outputs AC power in parallel, and does not output DC power. When the controller controls the input end of the first switch 5 to communicate with the second output of the first switch 5, the photovoltaic inverter outputs only direct current and does not perform grid-connected output. When the controller controls the input end of the first changeover switch 5 to simultaneously communicate with the first output end and the second output end of the first switch 5, the photovoltaic inverter is connected to the grid to output alternating current and output direct current.

Of course, in other embodiments, the control of the first switch 5 can also be performed by other methods, for example, comparing the power consumption of the input end and the output end by the comparator, and directly outputting the control signal to control the first switch 5 The input is in communication with the first output and/or the second output of the first changeover switch 5.

The following is an example of the operation of the photovoltaic inverter of the present invention:

The first switch 5 can switch the basic photovoltaic inverter unit between three working states, and realize switching between AC-DC-AC through three kinds of working states, and the three working states are respectively:

State 1: The controller controls the input end of the first changeover switch 5 to simultaneously communicate with the first output end and the second output end of the first changeover switch 5, at which time the DC sides of the N basic photovoltaic inverter units are connected in parallel, each basic The photovoltaic inverter units are all connected to the grid to output AC power. When the household appliances using direct current do not operate much, and the photovoltaic modules have a surplus of power generation capacity, or when N basic photovoltaic inverter units are connected to the grid for alternating current, state 1 can be used.

State 2: The controller controls the input end of the first changeover switch 5 to communicate with the first output end of the first changeover switch 5, and the input end of the first changeover switch 5 is not in communication with the second output end of the first changeover switch 5. At this time, the basic photovoltaic inverter unit performs independent grid-connected power generation and does not output direct current. State 1 or State 2 can be used when only grid-connected inversion is performed.

State 3: The controller controls the input end of the first changeover switch 5 to communicate with the second output end of the first changeover switch 5, and the input end of the first changeover switch 5 is not in communication with the first output end of the first changeover switch 5. At this time, the DC sides of the N basic photovoltaic inverter units are connected in parallel but the grid connection is not performed. When the power generation capacity of the photovoltaic cell module is insufficient to meet the consumption of the household appliance using the direct current, the state 3 can be used to reduce the power consumption of the grid as much as possible.

As shown in FIG. 3, the present invention also relates to an air conditioner comprising the photovoltaic inverter of any of the above embodiments, the air conditioner further comprising a second switch 9, a compressor inverter 13, and a power factor corrector (PFC, Power Factor Correction) 10. The rectifier 11, the EMC filter 16, and the third changeover switch 12. The AC grid 8 is in turn connected to the compressor 14 via a third changeover switch 12, an EMC filter 16, a rectifier 11, a power factor corrector 10 and a compressor inverter 13, the DC bus port passing through the second changeover switch 9 and the compressor in sequence The inverter 13 is connected to the compressor 14. It should be clear that the DC bus port here is matched to the DC bus port of the photovoltaic inverter, ie the DC bus port is adapted to the second output of the first changeover switch 5.

The second switch 9 is used for controlling the communication between the DC bus port and the air conditioner, that is, for controlling the communication between the PV inverter and the air conditioner, so that the air conditioner works by using the DC power generated by the PV inverter. The third switch 12 is used to control the AC grid to communicate with the air conditioner such that the air conditioner operates using the AC power of the AC grid. Preferably, the air conditioner further includes an air conditioning communication module 15 for data communication between the air conditioner and the photovoltaic inverter, and the air conditioning communication module 15 Matching with the communication module 4 in the photovoltaic inverter. In practical applications, the power of the photovoltaic cell component and the number of parallel connections of the basic photovoltaic inverter unit can be selected according to the power required for the normal operation of the air conditioner.

When the air conditioner uses the electric energy generated by the photovoltaic cell assembly 1, the controller controls the input end of the first changeover switch 5 and the second output of the first changeover switch 5 through the communication module 4 of the air conditioner communication module 15 and the photovoltaic inverter. The terminal is connected, and the direct current generated by the photovoltaic cell module 1 is sent to the DC bus port of the photovoltaic inverter, and the second switch 9 of the air conditioner controls the DC bus port of the air conditioner to communicate with the DC bus port of the photovoltaic inverter, and the air conditioner The third changeover switch 12 is turned off. At this time, the air conditioner operates using the electric energy generated by the photovoltaic cell module 1 instead of the electric energy of the AC power grid.

When the air conditioner uses the electric energy of the AC grid 8, the second switch 9 of the air conditioner controls the DC bus port of the air conditioner to be disconnected from the DC bus port of the photovoltaic inverter, and the third switch 12 of the air conditioner makes the air conditioner and the air conditioner The AC grid 8 is connected. At this time, the air conditioner operates using the power of the AC grid instead of the power generated by the photovoltaic module.

The above-mentioned embodiments are merely illustrative of several embodiments of the present invention, and the description thereof is more specific and detailed, but is not to be construed as limiting the scope of the invention. It should be noted that a number of variations and modifications may be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, the scope of the invention should be determined by the appended claims.

Claims

A photovoltaic inverter, comprising: a basic photovoltaic inverter unit;

The basic photovoltaic inverter unit includes a photovoltaic cell assembly, a DC-DC booster, a first switch, a grid-tied inverter, and a grid-connected filter; the photovoltaic cell assembly, the DC-DC booster The grid-connected inverter, the grid-connected filter and the alternating current grid are electrically connected in sequence;

The first switch includes an input end and two output ends, and the two output ends are respectively a first output end and a second output end, and an input end of the first switch switch is connected to the DC-DC liter The first output end of the first switch is connected to the input end of the grid-connected inverter for outputting alternating current; the second output of the first switch is used as a DC bus Port for outputting DC power.
The photovoltaic inverter of claim 1 wherein:

The basic photovoltaic inverter unit further includes a capacitor for voltage regulation, the capacitor being coupled between an output of the DC-DC booster and an input of the first changeover switch.
The photovoltaic inverter of claim 1 wherein:

The grid-connected filter is an EMC filter for filtering harmonics of the output current of the grid-connected inverter.
A photovoltaic inverter according to any one of claims 1 to 3, characterized in that:

The number of the basic photovoltaic inverter units is N, and the N basic photovoltaic inverters are connected in parallel through the second output end of the first switching switch; the number of the basic photovoltaic inverter units is N≥2 .
The photovoltaic inverter of claim 4 wherein:

The basic photovoltaic inverter unit also includes a communication module for data communication between the N of the basic photovoltaic inverter units.
The photovoltaic inverter of claim 5 wherein:

The communication modules of the N said basic photovoltaic inverter units are connected by a communication cable.
The photovoltaic inverter of claim 6 wherein:

The number of the communication cables is N-1.
The photovoltaic inverter of claim 1 wherein:

The photovoltaic inverter further includes a controller for controlling an input end of the first changeover switch to communicate with a first output end and/or a second output end of the first changeover switch.
An air conditioner, comprising: the photovoltaic inverter according to any one of claims 1-8;

a second switch, a compressor inverter, a power factor corrector, a rectifier, an EMC filter, and a third switch; the AC power grid sequentially passes through the third switch, the EMC filter, the rectifier, The power factor corrector and the compressor inverter are connected to a compressor, and a DC bus port is connected to the compressor through the second changeover switch and the compressor inverter in sequence.
The air conditioner according to claim 9, wherein:

The air conditioner further includes an air conditioning communication module for data communication between the air conditioner and the photovoltaic inverter.