# Review on Optimization Techniques of PV/Inverter Ratio for Grid-Tie PV Systems
## 2 Literature Review
### PV Array to Inverter Sizing Strategies
#### 2.2.2 DC/AC Sizing Ratio According to Third-Party Publications  
Currently, there is disagreement among PV specialists over whether it is economically feasible to create an optimization system. The \"rule-of-thumb\" approach has been cited by several academics as an effective way to determine the ideal inverter power ratings and PV array arrangement. Achieving the ideal size in their systems was explained in detail by other researchers as well. System design issues are becoming more crucial as optimization approaches ensure that the operating system functions optimally, reliably and with excellent conditions. As a result, system integrators must give careful consideration to balance-of-system (BOS) component selection inthe original design phase. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Ref.** & **PV/Inverter Ratio** & **Company/Country** & **Recommendations** \\ \hline
[56] & 0.88–1.1 & KACO New Energy & Power Ratio = PV\({}_{\text{GEN}}\)/P\({}_{\text{AC,INV}}\) \\ \hline
[57] & 0.7–1.0 & Power-One Inc. & PV Power @ STC/AC Power Nom. Max. of Inverter \\ \hline
[58] & 1.0 & Leonic Co., Ltd. & N/A \\ \hline
[54] & 0.8–1.2 & Danfoss Solar Inverters & Si PV = 0.94; Thin-Film = 0.94–0.90 and Thin-Film = 1.0 if Free-standing \\ \hline
[59] & 0.75–0.85 & AE PV-powered Inc & N/A \\ \hline
[60] & 0.8–1.2 & SMA Solar AG & PV/inverter power ratio (Vp) = input power inverter/peak power PV (0.9–1.0); Accepted Vp = 0.8–1.2 = (under extreme climate) \\ \hline
[61] & 0.8–1.1 & Energy, Staffelstein \& Engineering & DF (Dimensioning factor) = P\({}_{\text{solar}}\)/P\({}_{\text{WR,ACmax}}\) \textless{} 0.8: for DF = 0.8–1.15 = inverter too high; recommended for 35\({}^{\circ}\) inclination and south orientation; DF = (1.2–1.3): recommended facades (90\({}^{\circ}\) inclination), west or facing east; DF over 1.3: inverter too small; DF = (1.15 to 1.2): recommended to orient well to a very flat module under 15\({}^{\circ}\) inclinations or/and south (SW, SE). \\ \hline
[62] & 1.3–0.8 & Solar Photovoltaic Power: Designing Grid-Connected Systems, Malaysia & PR\({}_{\text{k}}=\frac{\text{P}_{\text{x,in}}}{\text{P}_{\text{rev,out}}}\) For Si PV = 0.80–0.75; for Thin–Film = 1.30–1.00 \\ \hline
[63] & 0.7–1.5 & UD, Delaware, US, Syllabus Book & Cost-effective and limited choice of inverter sizes to choose SF, even if overloaded occasionally. \\ \hline
[64] & 0.7–1.0 & Europe & Southern Europe (35–45\({}^{\circ}\) N) = 1.0–0.85; Central Europe (45–55\({}^{\circ}\) N) = 0.9–0.75; Northern Europe (55–70\({}^{\circ}\) N) = 0.8–0.7; \\ \hline
[65] & 0.8–1.2 & India & N/A \\ \hline
[66] & 0.7–0.65 & United States & N/A \\ \hline
[45] & 1–0.8 & United Kingdom & PV array-to-inverter ratio must be sized between 10.8 to 1:1 \\ \hline
[67] & 0.75 & Guideline/Standard Australia & The nominal AC output power of the inverter cannot be under 75\% of the peak power of the PV array. \\ \hline \end{tabular}
\end{table} 
Table 2: Summary of PV-to-inverter sizing ratio based on the country and the recommendation. Figure 3: Chronological summary of the main PV/inverter ratio sizing related approaches. In order to maximize the amount of energy injected into the grid, it is vital to combine inverter and PV array components for a grid-tied PV system in order to obtain the ideal size ratio. The optimal sizing ratio, according to [PERSON] et al. (2015), relies on the geographic location characteristics, the PV inverter, and the module material composition. To reduce the influence of the chosen inverter size on calculations and to prevent errors in power distribution, the study recommended that the precision of the measured time interval must not be five minutes or less. In contrast, the recommended size ratio took into consideration all power losses that would affect the inverter's power generation and conversion efficiency when it was in use. There are benefits and drawbacks to both undersized and large inverters according to size in relation to the rated power of the PV array.