Patent ID: 11936338
Assignee: TEIKYO UNIVERSITY
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H  G  Y | IPC G  H

Claim 9:
10. A solar battery cell operation voltage estimation system which estimates an operation voltage of each of m (m is an integer which is equal to or greater than 2) Solar battery cells which constitute a solar battery module and are connected in series, the system comprising:
a modulated light irradiation unit configured to irradiate any of the m solar battery cells with modulated light;
a light-shielded state setting unit configured to set a state in which a first solar battery cell, which is one solar battery cell of the m solar battery cells, is shielded from light;
an output current small change detection unit configured to irradiate the first solar battery cell with the modulated light and detect a small change of an output current of the solar battery module in the state in which the first solar battery cell is shielded from light, wherein
the modulated light irradiation unit irradiates each of the (m−1) solar battery cells excluding the first solar battery cell among the m solar battery cells with the modulated light and the output current small change detection unit detects the small change of the output current of the solar battery module in the state in which the first solar battery cell is shielded from light by the light-shielded state setting unit,
the system comprises:
a solar battery module operation voltage detection unit configured to detect an operation voltage of the solar battery module in the state in which the first solar battery cell is shielded from light; and
a calibration line generation unit configured to generate a first calibration line by connecting a first point and a second point which are plotted on coordinate axes in which a first axis corresponding to one axis is set as a voltage, and a second axis corresponding to the other axis is set as a relative ratio of a resistor,
the light-shielded state setting unit sets a state in which none of the m solar battery cells is shielded from light,
the modulated light irradiation unit irradiates a second solar battery cell which is a solar battery cell the operation voltage of which is to be estimated among the m solar battery cells with modulated light, the output current small change detection unit detects the small change of the output current of the solar battery module, the modulated light irradiation unit irradiates a third solar battery cell, which is a solar battery cell other than the second solar battery cell among the m solar battery cells, with the modulated light, the output current small change detection unit detects the small change of the output current of the solar battery module, and the solar battery module operation voltage detection unit detects an operation voltage of the solar battery module in the state in which none of the m solar battery cells is shielded from light,
the calibration line generation unit generates a second calibration line by connecting a third point and the second point which are plotted on the coordinate axes,
the system comprises:
a resistor relative ratio calculation unit configured to calculate a value of the relative ratio of the resistor of the second solar battery cell; and
a solar battery cell operation voltage calculation unit configured to calculate the operation voltage of the second solar battery cell, wherein
the solar battery cell operation voltage calculation unit calculates a fourth point, which is a point on the second calibration line at which a value of the second axis becomes a value of the relative ratio of the resistor of the second solar battery cell calculated by the resistor relative ratio calculation unit, and subsequently calculates a value of the first axis of the fourth point as the operation voltage of the second solar battery cell,
the first point shows a relationship between the value of the operation voltage of the first solar battery cell and the value of the relative ratio of the resistor in the state in which the first solar battery cell is shielded from light,
a value of the first axis of the first point is obtained by subtracting a total value of an open circuit voltage of each of the (m−1) solar battery cells from the operation voltage of the solar battery module in the state in which the first solar battery cell is shielded from light,
a value of the second axis of the first point is a maximum value of the relative ratio of the resistor,
the second point shows a relationship between a value of the operation voltage of any of the (m−1) solar battery cells and the value of the relative ratio of the resistor in the state in which the first solar battery cell is shielded from light,
a value of the first axis of the second point is the open circuit voltage of each of the (m−1) solar battery cells,
a value of the second axis of the second point is a minimum value of the relative ratio of the resistor,
a value of the first axis of the third point is obtained by subtracting a total value of the open circuit voltage of each of the (m−1) solar battery cells from the operation voltage of the solar battery module in the state in which none of the m solar battery cells is shielded from light, and
a value of the second axis of the third point is the maximum value of the relative ratio of the resistor.