Many solar inverters destined to connected installations to the network are specified in a manner comparatively brief by their manufacturer.  They dispose often manage a range of tension of comparatively wide entry.

It also is frequently indicated a nominal tension DC, to which these yield indications then can correspond.  Occasionally a bend of yield (generally printed in very small) is indicated (usually to this nominal tension).   These indications are often insufficient for the planning of installations PV sized in a manner optimum.  It is perfectly clear that the conversion yield depends on tension DC used (and it is true also in a least measure equally of tension AC).  It lacks in general rule of the indications on the dependence of the yield according to tension.  A manufacturer indicates only rarely the European yield for two or several different tensions.

Examples of yields measured according to tension are reproduced, but equally in various publications of the laboratory photovoltaic of the HTI.

The solar generator of an installation photovoltaic possesses a characteristic determined according to the temperature of unit and momentary solar radiance, which present in a determined point (Maximum Power Not at all MPP) a maximum power PMPP to a tension UMPP.  The among others stretched PV inverter to remain as much as possible on the MPP with values of period of sunshine and of variable temperatures.  (Maximum-Power-Point-Tracking).

Being given that the measure of the quality of this Maximum-Power-Point-Tracking is comparatively difficult, it generally is admitted that the inverter works exactly on this MPP.  But, according to the procedures MPPT implemented, gaps more or less important, all at least for certain powers and tensions, appear, which can reduce the production of energy of the body of the installation (in certain circumstances until some percent).  A tendency exists in solar units to improve the specifications, of manner that the power specifications are indicated for different periods of sunshine and the production of energy measured in real meteorological conditions.  One can therefore to obtain an improvement of the calculation of the production DC of the PV installations.  But, if the consecutive losses of energy to the errors in the mpp-tracking of the onduleurs also correctly are not taken in consideration, an important insecurity continues to exist for the determination of the production of energy of the coupled installations to the network.

The goal of this item is in first place to define the yield mpp-tracking MPPT next to define from and MPPT a global yield and to illustrate these magnitudes on the basis of some measures practice.  If, on the basis of carried out measures on a solar inverter,i this global yield tot is known for different tensions, the designer of an installation photovoltaic not only can adapt the solar generator and the inverter between them in a manner optimum on the basis of the power, but equally on the one of tension.  The values measured can equally be used in the existing programs of simulation, so well that a calculation of improved production is possible.