Inverter sizing equations
Continuous active power, load power factor, DC voltage, efficiency, and PV ratio are evaluated separately.
Pinv = Pload × (1+margin)Sinv = Pinv/PFIDC = 1000Pinv/(VDC × η)PPV = Pinv × DC/AC ratiowhere:
- Pinv
- Continuous inverter active-power reference[kW]
- Sinv
- Continuous apparent-power reference[kVA]
- IDC
- Nominal DC input current[A]
Recalculate DC current at minimum operating voltage.
How to use the Inverter Sizing Calculator
Estimate inverter continuous kW, kVA, surge rating, DC input current, AC output current, and PV DC array reference from load and design margins. Start by choosing the operating mode, then enter values from nameplates, measurements, or project documents in the units shown. The result updates immediately and keeps intermediate quantities visible for review.
- Confirm the system and calculation mode.
- Enter measured or manufacturer-rated values.
- Review the primary result and intermediate metrics.
- Continue with the related protection or equipment-selection checks.
Calculation method and validation
The equations and symbol definitions above show the complete calculation basis. Inputs are checked before calculation so zero, negative, incompatible, or physically impossible combinations are flagged instead of silently producing a misleading result.
How to interpret the result
Use the main result as a starting value and read every supporting metric. Single-phase AC current reference Surge kW is entered separately from continuous load Nominal DC voltage is used for preliminary current A passing or recommended result means the entered mathematical conditions are satisfied; it does not certify the complete installation or a particular product combination.
- Single-phase AC current reference
- Surge kW is entered separately from continuous load
- Nominal DC voltage is used for preliminary current
Selection limits and next checks
Preliminary engineering estimate only. Verify the final design against the current applicable standard, local rules, manufacturer data, and project conditions. Check minimum DC voltage for maximum current and conductor/protection sizing. PV string voltage and MPPT current require the exact module and inverter datasheets. Compare the output with the current applicable standard, local rules, exact VIOX product datasheet, environmental conditions, protection coordination, and the engineer's project requirements before procurement or installation.
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Assumptions
- Single-phase AC current reference
- Surge kW is entered separately from continuous load
- Nominal DC voltage is used for preliminary current
Important Warnings
- Preliminary engineering estimate only. Verify the final design against the current applicable standard, local rules, manufacturer data, and project conditions.
- Check minimum DC voltage for maximum current and conductor/protection sizing.
- PV string voltage and MPPT current require the exact module and inverter datasheets.