Regulation: Direct Coupling with Cascading

If the system is equipped with several pumps, the regulation should switch them ON according to the available PV power, in order that each pump runs near its optimal efficiency.

This opportunity improves drastically the performances of the direct coupling configuration, lowering the irradiance threshold and improving the operating at high irradiances.

But be careful: the determination of the irradiance threshold for starting the second pump is of great importance for the final performances (see the Results analysis for details) !

For pumps with MPPT power conditioning units, the cascading cannot be used unless the MPPT algorithms are suited for "Master/slave" operation. Indeed, the operating point of the characteristics of the PV array cannot of course be driven simultaneously by two independent MPPT devices.

Such an operation mode is not yet implemented in the present version of PVsyst.