The inverter is the power conversion device which interfaces the module’s DC output to the grid’s AC voltage. In order to maximize the HCPV generator’s energy throughput a key factor is the modules mismatching. This problem is emphasized with high concentration modules compared with the conventional photovoltaic systems: the HCPV module’s performance is the product of the cell’s conversion factor and the optics transmission factor.
This latter parameter adds a second spreading factor to the repeatability of the module’s performance. It is certainly possible to select the modules at the end of the manufacturing process and couple them correctly to avoid system mismatching, but it is still unknown the exact aging behaviour of each different module. Having more aging elements it is not unlikely to get different aging of different modules with some probability of an increasing mismatching over time.
Therefore the important objective is to design and develop a simple low cost module-inverter (a DC-AC power conversion device to be connected to the single module) with a high efficiency conversion (greater than 96%) that enables the independence of each module and guarantees the absence of mismatching over time. The HCPV generator will be made of one new inverter for each module; the inverter’s outputs will all be connected in parallel to the electric grid. The new inverter will also have a newly designed fast MPPT algorithm that will overcome some of the limits that affect CPV technology: the rapid variation of the module’s power output in non-clear sky conditions.
The new inverter will also be unique in that another objective of the project is to develop a very low cost spread spectrum radio frequency communication technology to enable the wireless control of all the HCPV generator’s inverters. This will allow important savings in the cables and connections and will raise the overall system’s reliability.
There will be also developed an automatic testing equipment able to test, calibrate and qualify the assembled inverters with very high throughput.