Device and method for performing maximum power point tracking for photovoltaic devices in presence of hysteresis

• US 10,488,879 B2
• Filed: 03/08/2018
• Issued: 11/26/2019
• Est. Priority Date: 03/09/2017
• Status: Active Grant

• Current Assignee: Ecole polytechnique fãdãrale de lausanne epfl (Schweizerische Eidgenossenschaft)
• Original Assignee: Ecole polytechnique fãdãrale de lausanne epfl (Schweizerische Eidgenossenschaft)
• Inventors: Pellet, Norman, Giordano, Fabrizio, Zakeeruddin, Shaik Mohammed, Gratzel, Michael
• Primary Examiner(s): Mershon, Jayne L
• Application Number:
  US15/915,114
• Publication Number:
  US 20180259990A1
• Time in Patent Office: 628 Days
• CPC Class Codes: G05F 1/67 to the maximum power available from a generator, e.g. from solar cell
• CPC Class Codes: H01G 9/2022 characterized by he counter electrode
• CPC Class Codes: H01G 9/2031 comprising titanium oxide, e.g. TiO2 H01G9/2036 takes precedence
• CPC Class Codes: H01L 31/028 including, apart from doping material or other impurities, only elements of Group IV of the Periodic Table
• CPC Class Codes: H01L 31/0322 comprising only AIBIIICVI chalcopyrite compounds, e.g. Cu In Se2, Cu Ga Se2, Cu In Ga Se2
• CPC Class Codes: H01L 31/0687 Multiple junction or tandem solar cells
• CPC Class Codes: H01L 31/0725 Multiple junction or tandem solar cells
• CPC Class Codes: H02S 20/32 specially adapted for solar tracking
• CPC Class Codes: H02S 40/30 Electrical components
• CPC Class Codes: H10K 30/151 the wide bandgap semiconductor comprising titanium oxide, e.g. TiO2
• CPC Class Codes: H10K 85/50 Organic perovskites; Hybrid organic-inorganic perovskites [HOIP], e.g. CH3NH3PbI3
• CPC Class Codes: Y02E 10/541 CuInSe2 material PV cells
• CPC Class Codes: Y02E 10/542 Dye sensitized solar cells
• CPC Class Codes: Y02E 10/544 Solar cells from Group III-V materials
• CPC Class Codes: Y02E 10/547 Monocrystalline silicon PV cells
• CPC Class Codes: Y02E 10/549 Organic PV cells
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers

Abstract

A photovoltaic system including a solar cell having a hysteretic behavior; and a power device configured to extract a maximum power from the solar cell by forcing power oscillations of the power output by the solar cell.

Claims

1. A method for tracking a maximum power output of a solar cell in presence of hysteresis, comprising the steps of:

sampling a voltage and a current of the solar cell (V(k), I(k));

determining a voltage variation and a current variation by substracting respectively from the sampled voltage a value of a previously sampled voltage (V(k)−

V(k−

1)) and from the sample current a previously sampled current (I(k)−

I(k−

1));

comparing respectively the voltage variation and the current variation to a determined typical system noise value and rejecting the sampled voltage value and the sampled current as non-significant if the comparing shows that the voltage variation and the current variation are inferior to the determined typical system noise value;

computing the power for the sampled voltage and current;

comparing the computed power to the previously computed power for previously sampled voltage and current;

incrementing the voltage by sign(dV)·

Δ

V_DAC if the computed power is greater than the previously computed power;

incrementing the voltage by sign(dV)·

Δ

V_DAC if the computed power is not greater than the previously computed power and the dV is positive and the relative decrement of power is smaller of the forward power threshold efw;

incrementing the voltage by sign(dV)·

Δ

V_DAC if the computed power is not greater than the previously computed power and the dV is negative and the relative decrement of power is smaller of the backward power threshold ebw;

incrementing the voltage by −

sign(dV)·

Δ

V_DAC if the computed power is not greater than the previously computed power and the dV is positive and the relative decrement of power is bigger of the forward power threshold efw; and

incrementing the voltage by −

sign(dV)·

Δ

V_DAC if the computed power is not greater than the previously computed power and the dV is negative and the relative decrement of power is bigger of the backward power threshold ebw.

2. The method according to claim 1, wherein the determined typical noise value of the system is about 1% of the current or voltage at maximum power point.

3. The method according to claim 1, wherein the selected forward power threshold efw and the backward power threshold ebw are in the range between 0.2% and 20% for both parameters.