# Review on Optimization Techniques of PV/Inverter Ratio for Grid-Tie PV Systems
## 2 Literature Review
### PV Array to Inverter Sizing Strategies
#### 2.2.1 Manufacturers' Recommendations Based on PV Guidelines  
The content of this section can be divided into three parts: the first part discusses the guidelines or inverter manufacturers' recommendations based on the PV sizing ratio; the second part, the table, briefly summarizes recommendations of some PV manufacturers and academics as concrete examples in commercial markets; and finally, in the third part, a graphical representation is presented for the chronological summary of the main PV-inverter ratio sizing studies. As per the DTI Sustainable Energy programs guideline [44; 45], the initial few weeks of operation can see increased electrical values. Nominal output power, Isc, and Voc will typically be larger during the initial phase of this operation than every rate determined using a conventional duplication feature. PV arrays can remain unplugged for the initial term to prevent the use of excessively large inverters. Based on the guidelines of the Clean Energy Council [46], the highest preliminary production of a-Si PV array is typically 25% greater than the power rating, hence the circuit breakers, switches, and inverters all need to be sized to prevent this from happening. This can often take up to six months after installation. Furthermore, the inverter size can be calculated by multiplying the values of the derating factor by the PV array peak power capacity at STC rating, which is reported to be 0.889 for thin film and 0.76 for a-Si-PV technologies, in Australia's guidelines [47]. Three different forms of derating variables, such as temperature, dirt, and manufacturing tolerance, were used to calculate such values for the two different PV panel technologies. If the inverter is designed efficiently, its nominal AC power output might be no less than 75% of the rated PV array power. The California Energy Commission (CEC) [48] stated that the field-based PTC rating of the input to the inverter output power (PV modules) is recommended as the best practice, and it must include a correction for the initial light-induced degradation. The PTC rating may imply greater performance under field operating conditions, as mandated by the CEC. Figure 2: Normalized revenue vs. DC/AC ratio at 35\({}^{\circ}\) Tilt, 0\({}^{\circ}\) Az, North Victoria/South NSW (35\({}^{\circ}\)) with fixed tilt angle on the left, while tracking tilt angle to the right. Sharp Electronics manufacturer [49] reported that for initial and stable condition values, the system design should be taken into account. Actual initial numbers for power will be greater by approximately15%; the power output is the Staebler-Wronski post-initial decay. Du Pont Apollo manufacturer [50] recommended that the power surpass the STC value as a state of the industrial qualifications during the stabilization phase, which takes place within the first month of service. Baoding Tian Wei manufacturer [51] reported that when determining component Isc, Voc, regulator sizes related to the PV power output, fuse sizes, conductor ampacities, and voltage ratings of the datasheet specification should be multiplied by a factor of 1.25. If referring to stable output, a design consideration must account for this variance as an option for the system. BP Solarex manufacturer [52] recommended that the output of the Millennium product will decline during the first several months of exposure. The rated electrical characteristics of Millennia take the attenuation into account, up to 6% more current, 12% more voltage, and 18% more initial power than specified. According to Sputnik Engineering inverter manufacturers [41], the distribution of the quantity of irradiation each year ina certain area affects the choice of the dimensioning factor. In order to help their customers design the ideal system, the manufacturer alsocreated a simulation program named Max-Design that is compatible with Solarmax's production. For a broad range of inverter sizing values from 0.80 to 1.10, the adjustment dimensioning factor (DF) may be used according to the specific location in their simulation [53].