Voltage mismatch of photovoltaic panels

What causes mismatch losses in PV modules?

Mismatch losses in PV modules occur when the I-V characteristics of the individual cells are significantly different. Mismatch losses occur due to a mismatch between output currents of the solar cells in the PV module. This is because current of a string is limited by the current of the lowest-current cell in a series interconnection.

How to determine if a current mismatch occurs in a PV module?

When there is a mismatch in the substrings of the PV module, the current at the two-thirds open circuit voltage will drop due to the conduction of the bypass diode. Therefore, by detecting the distortion of the low voltage section I-V curve, we can determine whether the current mismatch occurs in the PV module.

Why is mismatch loss important in a solar photovoltaic system?

Among various losses that occurred in the solar photovoltaic system, mismatch loss is imperative, which causes the system to perform poorly. Solar photovoltaic systems have made topical advances in the use of highly effective solar cell materials to achieve high efficiency.

How is solar array mismatch loss calculated?

The solar array mismatch loss is expressed in the percentage of the total array output. For example, if an array has a mismatch loss of 0.5% and the total array output is 1000 W, then the mismatch loss would be 0.005 kW (0.5% x 1000W). The solar array mismatch loss can be a significant contributor to overall system losses.

What causes a loss difference in a photovoltaic module?

Besides the module’s electrical characteristics, a loss difference includes string length and edge effects . When modules are connected to serial and parallel combination networks known as arrays, varying current-voltage characteristics of the photovoltaic modules result in a form of power loss called an electric mismatch.

What does a mismatch in voltage mean?

The total voltage produced is the sum of the individual cell voltages. Since the current must be the same, a mismatch in current means that the total current from the configuration is equal to the lowest current. A mismatch in the open-circuit voltage of series-connected cells is a relatively benign form of mismatch.