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

Claim 0:
1. A method for estimating 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 method comprising:
a first step of setting a state in which a first solar battery cell, which is one solar battery cell among the m solar battery cells, is shielded from light;
a second step of irradiating the first solar battery cell with modulated light and detecting 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;
a third step of irradiating 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 detecting 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;
a fourth step of detecting an operation voltage of the solar battery module in the state in which the first solar battery cell is shielded from light;
a fifth step of generating 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;
a sixth step of setting a state in which none of the m solar battery cells is shielded from light;
a seventh step of irradiating 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 the modulated light and detecting the small change of the output current of the solar battery module in the state in which none of the m solar battery cells is shielded from light;
an eighth step of irradiating 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 and detecting the small change of the output current of the solar battery module in the state in which none of the m solar battery cells is shielded from light;
a ninth step of detecting an operation voltage of the solar battery module in the state in which none of the m solar battery cells is shielded from light;
a tenth step of generating a second calibration line by connecting a third point and the second point which are plotted on the coordinate axes;
an eleventh step of calculating a value of the relative ratio of the resistor of the second solar battery cell;
a twelfth step of calculating 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 in the tenth step; and
a thirteenth step of calculating a value of the first axis of the fourth point as the operation voltage of the second solar battery cell, wherein
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.