Inverters without transformer attain high yields of conversion very until some percent above those of comparable devices to separation galvanic.
Measure yield MPP-Tracking static MPPT of the fakers of solar inverter generators of high stability are necessary for precise measures and reproducible of the static yield mpp-tracking [3, 5]; the fakers to linear diodes used by many test laboratories suit less to this effect owing to the problems of thermal stability that are them inherent. On the other hand, with fakers of solar generators profitable by PC, one can measure simultaneously many magnitudes on a power level (for example, MPPT, harmonic) and automatic measures are rendered possible by a spread out variation of the current following a determined
A certain period of stabilization (for example 60 seconds in the case of the inverters to regulation MPP slow and equally more) is necessary before the measure of the static yield MPPT after the adjustability of a new level of power. The current DC and tension DC are then, during the measure period that follows MT, if possible measured simultaneously to a frequency of high exploration (for example 1000 to 10 000 points of measure/s). The formation of an average on 50 mms or 100 mms is useful to eliminate the composing from 100 typical Hz of the inverters monophasic on the side DC.
The static yield mpp-tracking is then the report of the energy DC effectively absorbed by the inverter during the period of measure and energy DC PMPP • MT offered by the faker during this time.
The classical watt meters of precision are generally too slow to determine with sufficiently of precision the values MPP. This is the reason why the method of sweeping and of constitution of the described average above suits a lot better. The values of thus obtained measure can be indicated in the said diagrams of nebulosity. It is useful, to indicate the behavior mpp-tracking precise to different powers, to represent MPPT according to the power MPP and in the same diagram, to indicate on a second axis on one hand the real value measured of UMPP and other, the average of the tension of entry DC effective regulated by the inverter on the characteristic. Being given that the magnitude of entry of the mpp-tracking is the power MPP put to disposal by the solar generator PMPP, MPPT profitably is represented according to PMPP. It is on the other hand advantageous, to compare the behavior of the inverters of different magnitudes, to normalize this power MPP on the nominal power DC of the inverter, therefore to represent MPPT according to PMPP. Many inverters work with of small powers on a tension set up, being given that due disruptions to their frequency of internal commutation PWM make the identification difficult small signal of current to the low powers and consequently the correct
Consequently, for small powers, a wise functioning always is again possible thanks to this strategy. Nevertheless, for small powers, according to the position of tension MPP effective UMPP, more or less than energy is delivered, for the energy offered by the PV system completely is not used, in particular when this tension sets up is situated of tension UMPP effective. It would be probably preferable, for small powers, to work for example to 0.8 times the tension to previously measured emptiness UOC. The represented inverter on the other hand a behavior MPPT static superior noticeably, his tension of work UDC is only little underneath UMPP, even to small powers, which has for consequence of least losses of power and consequently a yield MPPT superior. To small powers, the behavior MPPT of the IG 30 is clearly superior.
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