# US 7,969,757 B2 · Apparatus providing bias to solar cells > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,969,757 B2 - Document ID: US7969757B2 - Status: Granted - Kind: B2 - Application number: 12/334,234 - Filed: 2008-12-12 - Published: 2010-06-17 - Granted: 2011-06-28 - Earliest claimed: 2008-12-12 - Assignees: Array Converter, Inc. - Inventors: Kent Kernahan - Web page: https://patentgrep.com/patent/US7969757B2 ## CPC - H10F 77/955: {for photovoltaic devices} - H02J 3/381: {Dispersed generators} - H02J 3/46: Controlling the sharing of generated power between the generators, sources or networks - H10F 77/123: comprising only Group II-VI materials, e.g. CdS, ZnS or HgCdTe - H02J 2101/24: Photovoltaics - Y02E 10/56: Power conversion systems, e.g. maximum power point trackers - Y10S 136/293: Circuits - Y10S 323/906: Solar cell systems - H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS ## Abstract Solar panels of certain technologies may experience a degradation of their efficiency as a result of exposure to sunlight, either prior to installation or during normal operation. A direct current to pulse amplitude modulated (“PAM”) current converter, denominated a “PAMCC”, is connected to the solar panel and to a source of alternating current. The PAMCC receives direct current from the solar panel and provides pulse amplitude modulated current at its output terminals at such times that the solar panel is capable to provide current, denominated “normal operation”. The PAMCC may be reconfigured to form a buck converter and a rectifier wherein the rectifier converts power received at the output (during normal operation) terminals to provide rectified, direct current to the buck converter. The buck converter provides direct current in the forward biased direction to the solar panel, thereby reconditioning the solar panel. Alternating current received at the output terminals of the PAMCC may be provided by an electric grid or by other means, such as other solar power converters. ## Claims ### Claim 1 A system for reconditioning solar cells, the system comprising: an array converter comprising: a first coil, including an input terminal and an output terminal, wherein the input terminal is connected to a positive terminal of a photovoltaic panel; a second coil, including an input terminal and an output terminal, wherein the input terminal of the second coil is connected to a negative terminal of the photovoltaic panel; a first switch connecting the output terminals of the first coil and the second coil; a first reconstruction filter coil having an input terminal and an output terminal, the output terminal connected to the power source; a second switch connected between the output terminal of the first coil and the input terminal of the first reconstruction filter coil; a second reconstruction filter coil having an input terminal and an output terminal, the output terminal connected to the power source; a third switch connected between the output terminal of the second coil and the input terminal of the second reconstruction filter coil, wherein the power source is connected across the output terminal of the first reconstruction coil and the output terminal of the second reconstruction coil; a fourth switch connected between the output terminal of the first coil and the input terminal of the second reconstruction filter coil; a fifth switch connected between the output terminal of the second coil and the input terminal of the first reconstruction filter coil; and a controller operatively connected to control gates of each of the first switch, the second switch, the third switch, the fourth switch, and the fifth switch. ### Claim 2 (depends on 1) The system for reconditioning solar cells of claim 1, wherein the external power source provides alternating current to the array converter, and the controller is configured to send signals to the control gates of the first switch, the second switch, the third switch, the fourth switch, and the fifth switch in such a manner that the array converter operates as an inverter and a buck converter to apply a bias current to the photovoltaic panel. ### Claim 3 (depends on 2) The system for reconditioning solar cells of claim 2, wherein the power source is alternating current provided by an electrical grid. ### Claim 4 (depends on 2) The system for reconditioning solar cells of claim 2, wherein the controller is configured to send signals to the control gates of the first switch, the second switch, the third switch, the fourth switch, and the fifth switch in such a manner that the bias current applied to the photovoltaic panel is forward biased with respect to the photovoltaic panel. ### Claim 5 A method for providing bias current to a photovoltaic panel for reconditioning solar cells in the photovoltaic panel, the method comprising: connecting an array converter system to a power source for receiving power and to the photovoltaic panel, wherein the array converter is configured to provide a version of the power received from the power source to the photovoltaic panel; configuring the array converter system as a rectifier and connecting an output of the rectifier to a buck type power converter; controlling the buck type power converter to provide direct current to the photovoltaic panel as a bias current configured to recondition the solar cells in the photovoltaic panel. ### Claim 6 (depends on 5) The method according to claim 5, wherein the power source is alternating current provided by an electrical grid. ### Claim 7 (depends on 5) The method according to claim 5, wherein the power source is provided by other array converter systems operatively connected to the array converter. ### Claim 8 (depends on 5) The method according to claim 5, wherein the power source is direct current. ### Claim 9 (depends on 5) The method according to claim 5, wherein the bias current is forward biased with respect to the photovoltaic panel. ### Claim 10 (depends on 5) The method according to claim 5, wherein the bias current is reverse biased with respect to the photovoltaic panel. ### Claim 11 (depends on 5) The method according to claim 5, wherein the solar cells in the photovoltaic panel are cadmium-telluride (Cd—Te) solar cells. ### Claim 12 (depends on 5) The method of claim 5, further comprising configuring the array converter system to receive direct current from the photovoltaic panel and output alternating current when not providing a bias current to the photovoltaic panel. ### Claim 13 (depends on 5) The method according to claim 5, wherein the array converter system comprises: a first coil, including an input terminal and an output terminal, wherein the input terminal is connected to a positive terminal of the photovoltaic panel; a second coil, including an input terminal and an output terminal, wherein the input terminal of the second coil is connected to a negative terminal of the photovoltaic panel; a first switch connecting the output terminals of the first coil and the second coil; a first reconstruction filter coil having an input terminal and an output terminal, the output terminal connected to the power source; a second reconstruction filter coil having an input terminal and an output terminal, the output termal connected to the power source; a third switch connected between the output terminal of the second coil and the input terminal of the second reconstruction filter coil, wherein the power source is connected across the output terminal of the first reconstruction coil and the output terminal of the second reconstruction coil; a fourth switch connected between the output terminal of the first coil and the input terminal of the second reconstruction filter coil; a fifth switch between the output terminal of the second coil and the input terminal of the first reconstruction filter coil; and a controller operatively connected to control gates of each of the first switch, the second switch, the third switch, the fourth switch, and the fifth switch. ### Claim 14 (depends on 13) The method of claim 13, wherein configuring the array converter system as a rectifier and connecting an output of the rectifier to a buck type power converter comprises configuring the controller to send signals to the control gates of the first switch, the second switch, the third switch, the fourth switch, and the fifth switch in such a manner that the array converter system operates as an inverter and a buck converter. ### Claim 15 (depends on 13) The method of claim 13, wherein the controller comprises memory and is configured with algorithms, the method further comprising determining when the photovoltaic panel should be reconditioned based upon one or more of time, measured parameters, and commands from an external source. ### Claim 16 A power generation system, comprising: a photovoltaic panel; and an array converter electrically coupled to the photovoltaic panel and to an external power source, the array converter comprising: a first coil, including an input terminal and an output terminal, wherein the input terminal is connected to a positive terminal of the photovoltaic panel; a second coil, including an input terminal and an output terminal, wherein the input terminal of the second coil is connected to a negative terminal of the photovoltaic panel; a first switch connecting the output terminals of the first coil and the second coil; a first reconstruction filter coil having an input terminal and an output terminal, the output terminal connected to the power source; a second reconstruction filter coil having an input terminal and an output terminal, the output termal connected to the power source; a third switch connected between the output terminal of the second coil and the input terminal of the second reconstruction filter coil, wherein the power source is connected across the output terminal of the first reconstruction coil and the output terminal of the second reconstruction coil; a fourth switch connected between the output terminal of the first coil and the input terminal of the second reconstruction filter coil; a fifth switch between the output terminal of the second coil and the input terminal of the first reconstruction filter coil; and a controller operatively connected to control gates of each of the first switch, the second switch, the third switch, the fourth switch, and the fifth switch, wherein the controller is configured to send signals to the control gates of the first switch, the second switch, the third switch, the fourth switch, and the fifth switch in such a manner that the array converter operates as an inverter and a buck converter to apply a bias current to the photovoltaic panel. ### Claim 17 (depends on 16) The power generation system of claim 16, wherein the photovoltaic panel comprises a plurality of cadmium-telluride (Cd—Te) solar cells. ### Claim 18 (depends on 16) The power generation system of claim 16, wherein the controller comprises: memory; and a processor coupled to the memory, wherein the processor is configured with algorithms to perform operations comprising determining when the photovoltaic panel should be reconditioned based upon one or more of time, measured parameters, and commands from an external source. ### Claim 19 (depends on 16) The power generation system of claim 16, wherein the controller is configured to send signals to the control gates of the first switch, the second switch, the third switch, the fourth switch, and the fifth switch in such a manner that the array converter receives direct current from the photovoltaic panel and outputs alternating current when the array converter is not providing a bias current to the photovoltaic panel. ### Claim 20 (depends on 16) The power generation system of claim 16, wherein the controller is configured to send signals to the control gates of the first switch, the second switch, the third switch, the fourth switch, and the fifth switch in such a manner that the array converter receives direct current from the photovoltaic panel and outputs direct current when the array converter is not providing a bias current to the photovoltaic panel.