Monitoring of distributed power harvesting systems using DC power sources

• US 8,473,250 B2
• Filed: 12/06/2007
• Issued: 06/25/2013
• Est. Priority Date: 12/06/2006
• Status: Active Grant

• Current Assignee: Solaredge Limited, Solaredge Technologies Incorporated
• Original Assignee: Solaredge Limited
• Inventors: Adest, Meir, Handelsman, Lior, Galin, Yoav, Fishelov, Amir, Sella, Guy
• Primary Examiner(s): Teixeira Moffat, Jonathan C
• Assistant Examiner(s): VO, HIEN XUAN
• Application Number:
  US11/951,419
• Publication Number:
  US 20080147335A1
• Time in Patent Office: 2,028 Days
• Field of Search: 702/60, 702/61, 307/56, 307/77, 307 80- 82
• US Class Current: 702/182
• CPC Class Codes: G01D 2204/125 Utility meter reading systems specially adapted for determining the environmental impact of user behaviour
• CPC Class Codes: G01D 2204/14 Displaying of utility usage with respect to time, e.g. for monitoring evolution of usage or with respect to weather conditions
• CPC Class Codes: G01D 2204/30 Remote utility meter reading systems specially adapted for metering the generated energy or power
• CPC Class Codes: G01D 2204/35 Monitoring the performance of renewable electricity generating systems, e.g. of solar panels
• CPC Class Codes: G01D 4/004 Remote reading of utility meters to a fixed location
• CPC Class Codes: G01R 21/133 by using digital technique
• CPC Class Codes: G01R 22/063 related to remote communication
• CPC Class Codes: H02J 13/00 Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
• CPC Class Codes: H02J 13/00002 characterised by monitoring
• CPC Class Codes: H02J 13/00009 using pulsed signals
• CPC Class Codes: H02J 13/00016 using a wired telecommunication network or a data transmission bus
• CPC Class Codes: H02J 13/00022 using wireless data transmission
• CPC Class Codes: H02J 13/00026 involving a local wireless network, e.g. Wi-Fi, ZigBee or Bluetooth
• 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 3/38 Arrangements for parallely feeding a single network by two or more generators, converters or transformers
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: Y02B 10/10 Photovoltaic [PV]
• CPC Class Codes: Y02B 70/30 Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level
• CPC Class Codes: Y02B 70/34 Smart metering supporting the carbon neutral operation of end-user applications in buildings
• CPC Class Codes: Y02B 90/20 Smart grids as enabling technology in buildings sector smart grids supporting the management or operation of end-user stationary applications in general, or like technologies with no associated climate change mitigation effect Y04S20/00
• CPC Class Codes: Y02E 10/50 : Photovoltaic [PV] energy
• CPC Class Codes: Y02E 10/56 : Power conversion systems, e.g. maximum power point trackers
• CPC Class Codes: Y02E 40/70 : Smart grids as climate change mitigation technology in the energy generation sector
• CPC Class Codes: Y02E 60/00 : Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
• CPC Class Codes: Y04S 10/123 : the energy generation units being or involving renewable energy sources
• CPC Class Codes: Y04S 10/30 : State monitoring, e.g. fault, temperature monitoring, insulator monitoring, corona discharge
• CPC Class Codes: Y04S 20/30 : Smart metering, e.g. specially adapted for remote reading
• CPC Class Codes: Y04S 40/121 : using the power network as support for the transmission
• CPC Class Codes: Y04S 40/124 : using wired telecommunication networks or data transmission busses
• CPC Class Codes: Y04S 40/126 : using wireless data transmission

Abstract

A monitoring system and method for monitoring performance of individual powers sources in a distributed power source system. A monitoring module is coupled to each of the power sources, or to each string of serially connected power sources, to monitor and collect data regarding current, voltage, temperature and other environmental factors at the power source. The collected data is transmitted over a power line to a central analysis station for analysis. Data collected from each source indicates malfunction or degradation at the source. Comparison of data collected from adjacent sources filters for environmental factors impacting neighboring sources such as cloudy days for a solar panel. Comparison of data collected from the same source at different times indicates soiling or degradation of the source with time or periodic events such as a moving shade from an adjacent building.

Claims

1. A distributed DC power harvesting system comprising:

a plurality of maximum power point tracking (MPPT) circuits, each configured to connect respectively to a corresponding one of a plurality of solar panels to individually perform maximum power tracking of the corresponding solar panel; and

a plurality of monitoring modules, each monitoring module connected respectively to one of the MPPT circuits to gather performance data at the maximum power point of the corresponding solar panel; and

a plurality of transmitters, each transmitter operatively connected to a corresponding one of the plurality of monitoring modules , wherein each transmitter is adapted for transmitting the performance data from the corresponding monitoring module, wherein each monitoring module includes a timer initialized whenever the corresponding solar panel starts to generate power, and wherein each monitoring module includes a controller configured to control transmission of the performance data according to an elapsed time from timer initialization.

2. The system of claim 1, further comprising the receiving station configured to receive the transmitted performance data from the plurality of transmitters, wherein the receiving station further comprises a sensor configured to measure at least one of a voltage and current on a power line configured to carry power from the plurality of solar panels.

3. The system of claim 1, wherein each transmitter comprises a wireless transmitter.

4. The system of claim 1, wherein one or more of the monitoring modules each comprise at least one of:

a current measurement module configured to collect current data from the corresponding solar panel; and

a voltage measurement module configured to collect voltage data from the corresponding solar panel.

5. The system of claim 1, wherein one or more of the monitoring modules each comprise a temperature sensor interface.

6. The system of claim 1, wherein each of the monitoring modules further comprises a randomizer configured to vary the elapsed time.

7. The system of claim 1, further comprising a memory configured to store the performance data accumulated over a time period beginning from when the corresponding solar panel starts to generate power.

8. The system of claim 1, wherein the solar panels are connected to form a plurality of serial strings of the solar panels, the system further comprising:

a connection box for parallel coupling of the serial strings of solar panels; and

,

a voltage measuring module measuring the voltage of the parallel coupling.

9. A method for monitoring performance in a distributed direct current (DC) power harvesting system, the method comprising:

perform, individually, maximum power tracking of each solar panel of a plurality of solar panels;

gathering performance data individually from each of the solar panels at a maximum power point of each solar panel; and

transmitting individually the performance data from each solar panel with a respective transmitter of a plurality of transmitters, wherein each transmission from each solar panel occurs at an individual predetermined elapsed setup time beginning from when each solar panel starts generating power in response to receiving sun light, respectively, and wherein the solar panels are spatially separated such that each solar panel starts the generating of power at a different time in response to receiving the sun light.

10. An apparatus comprising:

a maximum power point tracking (MPPT) circuit configured to control voltage or current of a corresponding solar panel to a maximum power point;

a monitoring circuit configured to gather performance data of the corresponding solar panel while being controlled by the MPPT circuit; and

a transmitter configured to transmit the performance data over a power line, wherein the transmitter is configured to transmit the performance data at a randomized time relative to transmission on the power line of other performance data from a plurality of other solar panels, wherein the corresponding solar panel and plurality of other solar panels are spatially separated such that each solar panel starts generating power at a different time in response to receiving sun light, and wherein the randomized time is based on when the corresponding solar panel starts the generating of power in response to the sun light.

11. The apparatus of claim 10, further comprising at least one of:

a current measurement circuit configured to collect current data from the corresponding solar panel;

a voltage measurement module configured to collect voltage data from the corresponding solar panel; and

a temperature sensor circuit configured to receive temperature data from a temperature sensor.

12. The apparatus of claim 10, further comprising:

a timer configured to generate an elapsed time; and

a randomizer configured to vary an elapsed time duration at which the randomized time occurs.

13. The apparatus of claim 10, further comprising a memory configured to store the performance data accumulated over a time period beginning from when the corresponding solar panel starts to generate power.

14. The apparatus of claim 10, further comprising:

a timer configured to generate the randomized time by being initialized randomly with respect to the plurality of other solar panels.

15. The apparatus of claim 10, further comprising a DC/DC converter configured to convert power from the corresponding solar panel and output the converted power to the power line.