Power supply circuits

• US 20070133241A1
• Filed: 05/06/2004
• Published: 06/14/2007
• Est. Priority Date: 05/06/2003
• Status: Active Grant

• Current Assignee: Tesla Inc.
• Original Assignee: Enecsys Limited
• Inventors: Chisenga, Lesley, Mumtaz, Asim, Amaratunga, Gehan Anil
• Granted Patent: US 8,067,855 B2
• Time in Patent Office: Days
• US Class Current: 363/131
• CPC Class Codes: H01L 27/1203 the substrate comprising an insulating body on a semiconductor body, e.g. SOI three-dimensional layout H01L27/0688
• CPC Class Codes: H02J 2300/24 of photovoltaic origin
• CPC Class Codes: H02J 2300/26 involving maximum power point tracking control for photovoltaic sources maximum power point systems in particular G05F1/67
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02J 3/388 Islanding, i.e. disconnection of local power supply from the network
• CPC Class Codes: H02M 7/4807 having a high frequency intermediate AC stage
• CPC Class Codes: H03K 17/6871 the output circuit comprising more than one controlled field-effect transistor
• CPC Class Codes: Y02B 10/10 Photovoltaic [PV]
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers

Abstract

This invention is generally concerned with power supply circuits, and more particularly, with circuits to supply power to a mains supply, such as domestic grid mains, from a photovoltaic device. A photovoltaic power conditioning circuit for providing power from a photovoltaic device to an alternating current mains power supply line, the circuit comprising: a DC input to receive DC power from said photovoltaic device; an AC output configured for direct connection to said AC mains power supply line; a DC-to-AC converter coupled to said DC input and to said AC output to convert DC power from said photovoltaic device to AC power for output onto said power supply line; and an electronic controller directly coupled to said power supply line to measure a voltage of said power supply line and a current in said supply line and to control said DC-to-AC converter responsive to said measuring.

Claims

1. A photovoltaic power conditioning circuit for providing power from a photovoltaic device to an alternating current mains power supply line, the circuit comprising:

a DC input to receive DC power from said photovoltaic device;

an AC output configured for direct connection to said AC mains power supply line;

a DC-to-AC converter coupled to said DC input and to said AC output to convert DC power from said photovoltaic device to AC power for output onto said power supply line; and

an electronic controller directly coupled to said power supply line to measure a voltage of said power supply line and a current in said supply line and to control said DC-to-AC converter responsive to said measuring.

2. A photovoltaic power conditioning circuit as claimed in claim 1 wherein said controller is configured to determine first and second frequencies of said voltage and of said current respectively, and to control said DC-to-AC converter responsive to a difference between said first and second frequencies.

3. A photovoltaic power conditioning circuit as claimed in claim 2 wherein said controller is further configured to control said DC-to-AC converter to progressively change an operating frequency of said converter, to monitor said first and second frequencies to determine whether said first frequency substantially follows said second frequency during said progressive change, and, responsive to said determination, to inhibit power output from said photovoltaic device to said mains power supply line.

4. A photovoltaic power conditioning circuit as claimed in claim 1 comprising a plurality of power semiconductor devices, a said power semiconductor device comprising a device conducing power from said photovoltaic device to said mains power supply line;

and further comprising a plurality of drivers for said driving power semiconductor devices, and wherein said power devices and said drivers are integrated on a common semiconductor substrate.

5. A photovoltaic power conditioning circuit as claimed in claim 4 wherein said power devices comprise lateral devices and employ silicon-on-insulator (SOI) technology.

6. A photovoltaic power conditioning circuit as claimed in claim 1 further comprising a DC-to-DC converter having an input coupled to said DC input and having an output coupled to an input of said DC-to-AC converter.

7. A photovoltaic power conditioning circuit as claimed in claim 1 further comprising a rechargeable battery interface.

8. A photovoltaic power conditioning circuit as claimed in claim 7 further comprising a maximum power point tracking (MPPT) unit coupled to said DC input;

and wherein said battery interface has an input coupled to an output of said MPPT circuit.

9. A photovoltaic power conditioning circuit as claimed in claim 1 wherein said controller comprises a processor coupled to non-volatile program memory storing processor control code to control said processor to measure said voltage and said current and to output a control signal to control said DC-to-AC converter as claimed.

17. A photovoltaic power conditioning circuit as claimed in claim 1, wherein said DC-to-AC converter comprises two stages, a first AC stage and a second AC stage linked by a coupling element, the second stage operating at a higher voltage than the first, the first stage comprising a plurality of MOSFETs, the second stage comprising a plurality of IGBTs

10. A method of conditioning power from a photovoltaic device for provision to an AC mains power supply line, the method comprising:

reading data for a voltage of said supply line and a current in said supply line into an electronic controller;

determining a first frequency for said voltage and a second frequency for said current using said electronic controller; and

conditioning said power using said electronic controller responsive to a difference between said first and second frequencies.

11. A method as claimed in claim 10 wherein said conditioning comprises converting DC power from said photovoltaic device to AC power for said AC supply line;

and wherein the method further comprises controlling said converting to change said second frequency, monitoring said first and second frequencies, and ceasing to supply power to said AC supply line where said controlling results in less than a threshold difference between said first and second frequencies.

12. A controller for a photovoltaic power supply system configured to perform the method of claim 10.

13. Computer program code on a carrier, to, when running, perform the method of claim 10.

14. A power conditioning circuit, in particular an integrated circuit, comprising two stages, a first AC stage and a second AC stage linked by a coupling element, the second stage operating at a higher voltage than the first, the first stage comprising a plurality of MOSFETs, the second stage comprising a plurality of IGBTs.

15. A power conditioning circuit, as claimed in claim 14 wherein both said stage and said second stage comprise a full bridge.

16. (canceled)