Universitat Politècnica de Catalunya - UPC

Low-power FOCV MPPT controller with automatic adjustment of the sampling time and period

Posted by Universitat Politècnica de Catalunya - UPCResponsive · Patents for licensing · Spain

Summary of the technology

A new simple control scheme for dynamically adjusting the sampling time and period of a Fractional Open Circuit Voltage (FOCV) MPPT controller has been developed and patented. Partners to further develop the system and/or to establish commercial agreements along with technical cooperation are sought.

Universitat Politècnica de Catalunya - UPC

The Challenge

Maximum Power Point Trackers (MPPTs) have been widely used in high power applications to achieve maximum power from photovoltaic (PV) panels. In low power applications, such as autonomous sensor nodes and traffic lights and signals, simple MPPT controllers are required to be economically feasible. Fractional Open Circuit Voltage (FOCV) controllers are an alternative. These type of controllers periodically disconnect the PV panel and sample its open circuit voltage (VOC). Then, the voltage at the maximum power point (VMPP) is determined from an empirical linear relationship with VOC. Unfortunately, the momentary disconnection of the PV panel implies a power loss that must be minimized to achieve maximum power efficiency. The required sampling time of VOC inversely depends on the irradiance over the PV panel and so, it is not optimized by commercial FOCV controllers in which a fixed sampling time and period are used.

The Technology

The novel controller solution determines the sampling time and period by using a digital counter, an Op-amp integrator circuit and a comparator. A commercial Pulse Frequency Modulation (PFM) switching regulator IC is used as power conditioner to bias the PV panel.
The counter counts the PFM cycles and initiates a sampling state when a limit number is reached. A proportional sampling time is achieved using the integrator and the comparator.
As the time length of the PFM cycles are inversely proportional to the PV current (and thus to the irradiance), the resulting sampling time and period are properly adjusted according to the irradiance conditions.

Current stage of development

The controller was successfully tested in a laboratory prototype with 20 mW PV panels.

Applications and Target Market

The technology was developed for low-power PV systems in which FOCV is the best choice to implement an MPPT controller. This technology could be of interest for companies that develop low-power energy PV devices.

Innovative advantages

Minimum time disconnection of the PV panel.
Variable tracking speed of the MPTT. The sampling frequency is decreased in low irradiance conditions to reduce the power consumption.
Low-cost control circuit.
Low-power consumption.

Intellectual property status

Granted Patent
Technology available for licensing with technical cooperation Patent Status Priority application

Technology Owner

Universitat Politècnica de Catalunya - UPC

Technology Transfer Office

Related keywords

  • Electronics, IT and Telecomms
  • Energy Technology
  • Energy production, transmission and conversion
  • Energy efficiency
  • Electronics, Microelectronics
  • Energy Market
  • Power Supplies
  • low-power energy
  • pv systems
  • focv

About Universitat Politècnica de Catalunya - UPC

Technology Transfer Office from Spain

The Universitat Politècnica de Catalunya - BarcelonaTech is a public institution dedicated to higher education and research in the fields of engineering, architecture and science, which contributes its knowledge and expertise in order to increase scientific output, transfer its results to society and provide a network of scientific and technical state-of-the-art facilities and technology valorization services that place us at the leading edge of innovation and economic development.

The UPC has established itself as a driver of innovation and is the technology partner of choice for companies and organizations with which it develops projects and builds partnerships. A role borne out by the numerous agreements and research projects that have been set in motion by groups, organizations and laboratories; the creation of new technology-based companies; the generation and exploitation of patents, and the scientific and technical services UPC makes available to its environment in order to generate progress and employment.

The Technology Transfer Office (SGI) is responsible of Designing, coordinating and implementing research valorisation strategies, carrying out the protection policy of the research results, marketing these results through license contracts and designing and setting up the University's enterprise creation model in order to transfer the results of the research to the market, protect and commercialize these results, promote the culture of entrepreneurship and innovation, and create technology-based companies within the UPC environment.

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