Indian researchers have proposed a new concept to improve the yield of rooftop solar PV systems under partial shading. This concept combines conventional cross-coupled (TCT) techniques with partial power processing converters (PPPC) using a resonant switched capacitor converter (RSC) and a switched coil converter (SLC).
The new design, which the researchers describe as cost-effective and easy to manage, combines conventional TCT techniques for photovoltaic systems with PPPCs.
“We are currently designing the hardware for the proposed concept,” researcher Subhash Vitthalrao Murkute said. pv magazine. “TCT is the most popular and widely used connection for PV modules in the PV array because it offers better performance in all types of partial shade.”
However, bypass diodes and blocking diodes limit the power boost capacity during partial shading. Advanced array reconfiguration techniques can increase this power limit, but they also increase the cost and complexity of the system.
The research team referred to the use of PPPCs by stating that their application only allows for handling the power mismatch between series PV modules during partial shading. The proposed system is based on the interconnection of photovoltaic arrays using TCT techniques and includes the use of a coupled capacitor converter for partial power processing.
“This topology requires two switches for each PV module connected in parallel in a row,” the researchers said. “The main disadvantage of this system is that it requires more hardware and also complex closed-loop control to track the maximum power point (MPPT) control to maximize power.”
The system uses a resonant switched capacitor converter (RSC) together with a switched inductor converter (SLC). The researchers said this particular combination reduces the number of switches to just one per row instead of two.
They tested a 5 kW rooftop solar PV system with 20 solar panels under different partial shading conditions. They also compared its performance with that of conventional TCT and series-parallel (SP) approaches.
“The results show that the power conversion efficiency of the proposed system was 95-99 percent under all shading conditions, which is higher than SP and TCT,” the Indian team said. “It shows that the proposed system under all partial shading conditions gives a higher output power.”
The team said the power yield improvement compared to SP and TCT was 4-30 percent and 0.5-19 percent higher, respectively.
“The results show that the proposed hybrid system improves the performance of the PV system under all kinds of shading conditions,” they concluded.
The researchers described the proposed system design as “A Novel High-Performance Photovoltaic System Architecture for Mitigation of Partial Shading Effects,” published recently e-Prime – Advances in electrical engineering, electronics and energy.