What is PV array Reconfiguration?

Before digging deep into PV array reconfiguration, we must first understand partial shading in PV arrays.

1. What is partial shading?

Partial shading refers to the shadowing of solar cells' closed surface caused by sun exposure. As a result, the amount of electricity generated by solar cells will be reduced. Partial shading reduces the power output of solar panels by half. If even one of the 36 cells on a solar panel is partially shaded, the entire panel will produce less power. Because all cells are interconnected in a series string, the weakest cell will reduce the strength of the others to match it.

What happens during partial shading conditions?

In a partial shading operation, the unshaded PV array modules receive a certain amount of solar energy while the shaded modules receive less. The shading factor and the number of shaded modules define the partial shading working condition. A variety of connections are used to connect the PV modules in an array. The primary factor reducing PV array efficiency is partial shading (PS).

What causes partial shading?

It happens as a result of buildings, passing clouds, and pole shade. The PS effect is reduced by connecting bypass diodes across each panel. The PV modules are shielded from the hot spot effect and thermal stress by these bypass diodes. A bypass diode, however, produces several peaks in the P-V and I-V curves. Therefore, the worldwide peak power may occasionally be missed by traditional maximum power point tracking (MPPT) systems.

2. What is PV array reconfiguration?

Array reconfiguration is a technique for physically or electronically repositioning the panels in a PV array in order to disperse the concentrated shade over the array. Furthermore, all reconfiguration techniques contribute to the overall goal of reducing row current disparity.

The primary factor causing power loss is row current differences. This panel relocation method, which is used to reduce the row current difference, involves physically or electrically moving the panel so that the shadow that was concentrated in one region is dispersed.

Benefits of PV array reconfiguration

The advantages of PV array reconfiguration techniques are listed below:

1. The array reconfiguration disperses the shade to achieve the unique maximum power; 

2. The array reconfiguration reduces the number of bypasses required to achieve full array voltage  

3. Rearranging the array reduces mismatch power loss.

3. Need for PV array reconfiguration

Partially shading reduces PV array output power by causing mismatch power losses. Reconfiguring PV array topologies has become a substitute for increasing power.

4. Different PV configurations

• Series
•  Parallel 
• Series-parallel (SP)
• Total-Cross-Tied (TCT)
•  Bridge-Link (BL)
•  Honey-Comb (HC)

5. Different techniques for PV array reconfiguration

• Physical Reconfiguration:

The physical reconfiguration relies on shade dispersion systems to increase power (SDS). SDS's shade distribution employs a number of puzzle patterns. The modules and electrical wiring change depending on the problem. Unlike dynamic reconfiguration, these techniques are more efficient than traditional PV array topologies and do not require sophisticated controllers or sensors.

• Dynamic Reconfiguration

Dynamic reconfiguration modifies the electrical connections whilst still maintaining the module's position. The distribution of the shade throughout an array is made possible by a change in the electrical connections.