Method for operating a photovoltaic system

• US 10,305,287 B2
• Filed: 08/31/2016
• Issued: 05/28/2019
• Est. Priority Date: 09/04/2015
• Status: Active Grant

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Hoerist, Gerald, Puerstl, Gerrit, Trnka, Alexander
• Primary Examiner(s): Kaplan, Hal
• Assistant Examiner(s): Vu, Toan T
• Application Number:
  US15/253,194
• Publication Number:
  US 20170070053A1
• Time in Patent Office: 1,000 Days
• Field of Search: 307 84
• CPC Class Codes: H02J 2300/24 of photovoltaic origin
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02M 1/36 Means for starting or stopping converters
• CPC Class Codes: H02M 3/1582 Buck-boost converters H02M3/1584 takes precedence
• CPC Class Codes: H02S 40/32 comprising DC/AC inverter means associated with the PV module itself, e.g. AC modules
• CPC Class Codes: H02S 40/38 Energy storage means, e.g. batteries, structurally associated with PV modules
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers
• CPC Class Codes: Y02E 70/30 Systems combining energy storage with energy generation of non-fossil origin

Abstract

A method for operating a photovoltaic system which includes solar panels, at least one DC-DC converter and an intermediate DC circuit, wherein the switching elements of the DC-DC converter are brought into a switching state which forms a permanent current path between the output of the solar panels and the intermediate circuit during a transition phase between an unloaded and loaded state of the solar panels.

Claims

1. A method for operating a photovoltaic system comprising solar panels, at least one DC-DC converter and an intermediate DC circuit, the method comprising:

closing a main contactor and a switching element of a plurality of switching elements to close a current path via the main contactor, the switching element, a coil and a first free-wheeling diode such that the solar panels are loaded and a full no-load voltage cannot develop; and

bringing the plurality of switching elements of the DC-DC converter into a switching state which forms a permanent current path between the output of the solar panels and the intermediate circuit during a transition phase between unloaded and loaded state of the solar panels.

2. The method as claimed in claim 1, wherein the at least one DC-DC converter comprises a buck-boost converter.

3. The method as claimed in claim 1, wherein the plurality of switching elements of the DC-DC converter comprise IGBT transistors.

4. The method as claimed in claim 2, wherein the plurality of switching elements of the DC-DC converter comprise IGBT transistors.

5. The method as claimed in claim 1, wherein at least one inverter for connection to an AC voltage network is connected to the intermediate DC circuit.

6. The method as claimed in claim 1, wherein a battery system for storing the electrical energy is connected to the intermediate DC circuit.

7. A photovoltaic system, comprising:

solar panels;

at least one DC-DC converter;

an intermediate DC circuit;

a switch for actuating the DC-DC converter and closing a current path via a main contactor, a coil and a first free-wheeling diode such that the solar panels are loaded and a full no-load voltage cannot develop and such that during a transition phase between an unloaded and loaded state of the solar panels, switching elements of the DC-DC converter have a switching state, which forms a permanent current path between an output of the solar panels and the intermediate circuit DC circuit.