Photovoltaic module

Patent metadata

Field	Value
Publication number	US-9602048-B2
Application number	US-201414479179-A
Country	US
Kind code	B2
Filing date	Sep 5, 2014
Priority date	Jan 15, 2014
Publication date	Mar 21, 2017
Grant date	Mar 21, 2017

Abstract

A photovoltaic module is discussed. The photovoltaic module includes a solar cell module including a plurality of solar cells and a junction box attached to a rear surface of the solar cell module, the junction box including a power conversion module to convert direct current (DC) voltage supplied from the solar cell module into alternating current (AC) voltage and to output the AC voltage, wherein the power conversion module included at least one bypass diode to receive the DC voltage from the solar cell module, a converter unit to power-convert the DC voltage from the at least one bypass diode, the converter unit including at least three interleaving converters, a capacitor to store voltage output from the converter unit, and an inverter unit to output the AC voltage using the voltage stored in the capacitor. Consequently, it is possible to stably output AC voltage.

First claim

What is claimed is:

1. A photovoltaic module comprising:
a solar cell module comprising a plurality of solar cells; and
a junction box attached to a rear surface of the solar cell module, the junction box comprising a power conversion module to convert direct current (DC) voltage supplied from the solar cell module into alternating current (AC) voltage and to output the AC voltage,
wherein the power conversion module comprises:
at least one bypass diode to receive the DC voltage from the solar cell module;
a converter unit to power-convert the DC voltage from the at least one bypass diode, the converter unit comprising at least three interleaving converters;
a capacitor to store voltage output from the converter unit;
an inverter unit to output the AC voltage using the voltage stored in the capacitor; and
a controller to control operations of the converter unit and the inverter unit,
wherein the solar cell module includes a frame to fix an edge of the solar cell module and the junction box has a smaller thickness than the frame, and
wherein, when a current flowing in switching devices of the at least three interleaving converters or a voltage applied to the switching devices is zero-crossed after the switching devices of the at least three interleaving converters are turned on and off, the controller turns on the switching devices again.

2. The photovoltaic module according to claim 1 , wherein the power conversion module further comprises:
an input voltage detection unit to detect voltage input to the converter unit;
an input current detection unit to detect current input to the converter unit;
a DC end voltage detection unit to detect voltage input to the capacitor;
an output voltage detection unit to detect voltage output from the inverter unit; and
the controller to control a switching operation of the converter unit based on the detected input voltage, input current, and DC end voltage, and to control a switching operation of the inverter unit based on the detected DC end voltage and output voltage.

3. The photovoltaic module according to claim 1 , wherein the converter unit power-converts the DC voltage from the at least one bypass diode to output a pseudo DC voltage, and the inverter unit power-converts the pseudo DC voltage to output the AC voltage.

4. The photovoltaic module according to claim 1 , wherein the controller changes switching frequencies of the at least three interleaving converters.

5. The photovoltaic module according to claim 4 , wherein the controller controls the switching frequencies of the at least three interleaving converters to be increased, as a change rate of a target sine waveform for a pseudo DC voltage output from the converter unit is increased.

6. The photovoltaic module according to claim 1 , wherein the controller changes switching periods of the at least three interleaving converters and changes phase differences between the at least three interleaving converters during operation sections of the at least three interleaving converters, after change of the switching periods of the at least three interleaving converters.

7. The photovoltaic module according to claim 6 , wherein, when the switching periods of the at least three interleaving converters are increased, the controller changes the phase differences between the at least three interleaving converters during the operation sections of the at least three interleaving converters, such that the phase differences between the at least three interleaving converters during the operation sections of the at least three interleaving converters are less than the phase differences between the at least three interleaving converters during the operation sections of the at least three interleaving converters before the increase of the switching periods of the at least three interleaving converters.

8. The photovoltaic module according to claim 6 , wherein the controller changes the phase differences between the at least three interleaving converters during the operation sections of the at least three interleaving converters, such that the phase differences between the at least three interleaving converters during the operation sections of the at least three interleaving converters are sequentially approximate to a reference phase difference after the change of the switching periods of the at least three interleaving converters.

9. The photovoltaic module according to claim 6 , wherein, when the switching periods of the at least three interleaving converters are increased, the controller increases an overlapping region between the operation sections of the at least three interleaving converters.

10. The photovoltaic module according to claim 1 , wherein the controller selectively operates at least one of the at least three interleaving converters.

11. The photovoltaic module according to claim 1 , wherein each of the at least three interleaving converters comprises a tap inductor converter.

12. The photovoltaic module according to claim 1 , wherein each of the at least three interleaving converters comprises a flyback converter.

13. A photovoltaic module comprising:
a solar cell module comprising a plurality of solar cells; and
a junction box attached to a rear surface of the solar cell module, the junction box comprising a power conversion module to power-convert DC voltage supplied from the solar cell module and to output the power-converted DC voltage,
wherein the power conversion module comprises:
at least one bypass diode to receive the DC voltage from the solar cell module;
a converter unit to convert the DC voltage from the at least one bypass diode, the converter unit comprising a plurality of interleaving converters; and
a controller to control the converter unit, and wherein the controller changes switching periods of switching devices of the interleaving converters,
wherein the controller changes the switching periods of the switching devices of the interleaving converters based on whether a current flowing in the switching devices or a voltage applied to both ends of the switching devices is zero-crossed after the switching devices are turned on and off.

14. The photovoltaic module according to claim 13 , wherein
the converter unit power-converts the DC voltage to output a pseudo DC voltage, and
the controller changes the switching periods of the switching devices of the interleaving converters based on duties to drive the switching devices of the interleaving converters and sets the switching periods of the switching devices of the interleaving converters to be increased in proportion to an increase of the duties.

15. The photovoltaic module according to claim 13 , wherein
the converter unit power-converts the DC voltage to output a pseudo DC voltage, and
the controller controls the converter unit such that the output pseudo DC voltage follows a target sine waveform and sets the switching periods of the converter unit to be decreased in inverse proportion to an increase of a change rate of the target sine waveform.

16. The photovoltaic module according to claim 13 , wherein the converter unit comprises at least three interleaving converters.

Assignees

• Lg Electronics Inc

Inventors

• Kang Younjong
• Kim Myonghwan
• Ham Myungsoo
• Ham Wontae
• Park Giyob
• Yoon Byoungsu

Classifications

• H02S40/32 Primary

  comprising DC/AC inverter means associated with the PV module itself, e.g. AC modules · CPC title

• H02M7/493

  the static converters being arranged for operation in parallel · CPC title

• H02M1/14

  Arrangements for reducing ripples from DC input or output · CPC title

• H02J7/35

  with light sensitive cells · CPC title

• Y02E10/56

  Power conversion systems, e.g. maximum power point trackers · CPC title