Which inverter type fits your solar project?
Equipment
The inverter drives conversion efficiency, monitoring capability and much of the maintenance cost of a PV system. This guide compares the four families in common use and suggests how to choose by project size, roof geometry and storage plans.
In this guide
01
Four inverter families
- String inverter: each unit takes several PV strings; the most common choice for industrial roofs thanks to its balance of cost, efficiency and replaceability.
- Central inverter: large centralised units for ground-mount plants or very large uniform roofs; lowest cost per kW but a fault affects a wide area.
- Hybrid inverter: integrates battery management, enabling load shifting or backup during grid outages.
- Micro-inverter: mounted per module (or per few modules), ideal for small roofs, multiple orientations or localised shading.
02
Datasheet parameters that matter
- Maximum and weighted (European) efficiency, not just the peak figure.
- Allowed DC/AC ratio, number of MPPTs and MPPT voltage window – they directly shape string layout on multi-orientation roofs.
- IP rating, operating temperature range and derating behaviour under Vietnamese conditions.
- Active and reactive power control, zero-export support and monitoring protocols (Modbus, API).
- Certification against international standards (IEC) and availability of warranty and local technical service.
03
Choosing by size and roof geometry
- Small roofs, multiple orientations, partial shading: micro-inverters or multi-MPPT string inverters.
- Factory roofs from 100 kWp to a few MWp on one orientation: mid-power string inverters grouped by roof area.
- Large uniform ground-mount or roof areas: consider central inverters to reduce capex.
- Storage, backup or evening load shifting required: hybrid inverters or a separate bidirectional converter with BESS.
This is a general technical selection framework, not a brand ranking; the final configuration depends on simulation results and grid connection conditions for each project.
04
Frequent selection mistakes
- Sizing inverter power too close to module power (losing yield) or far too high (wasting capex).
- Combining strings with different module counts or orientations on the same MPPT.
- Ignoring ventilation and ambient temperature at the inverter location, causing midday derating.
- Not verifying monitoring integration before handover, leaving the system unable to report PR.
Frequently asked questions
Are micro-inverters better than string inverters?
Neither is universally better: micro-inverters handle shading and multi-orientation roofs better, while string inverters usually cost less per kWp and are easier to maintain centrally on large industrial roofs.
What DC/AC ratio should we use?
It is chosen from local irradiation, roof orientation and the level of midday clipping you accept; the right approach is to simulate a few ratios and weigh the extra yield against the extra equipment cost.
Should we buy a hybrid inverter even without batteries yet?
If a BESS addition is firmly planned within the next few years, a hybrid inverter lowers the upgrade cost later; without such a plan, compare the price premium against expanding later with a separate bidirectional converter.
Related guides
Equipment selection
Which solar brand should you choose?
How to select solar equipment brands on verifiable criteria: IEC certification, efficiency, warranty terms, degradation and local service. Why Orca Energy favours JA Solar modules and Sungrow inverters on commercial rooftop projects in Vietnam.
Energy storage
BESS for industrial users: applications and sizing
What BESS does in a factory: peak shaving, shifting solar generation, backup during outages and supporting power purchase contracts. How to size power and energy, choose cell technology and meet safety requirements.
Operations & maintenance
Solar O&M: what to do and how often
A practical guide to operating and maintaining rooftop solar: monthly, quarterly and annual task lists, tracking performance ratio, finding faulty modules with thermography, and the KPIs worth putting in an O&M contract.
Working principle
How does solar power work?
Animated explanation of how solar power is generated: the photovoltaic effect inside the cell, DC current from the modules, the inverter converting DC to grid-synchronous AC, how energy reaches on-site loads and the grid, and what drives real yield.
Sources
This guide compiles reference information from legal documents and official sources; it is not legal advice. Technical and financial ranges are industry reference values — project decisions require a site-specific survey.
Need a solar plan for your plant?
Orca Energy surveys the roof, analyses the load profile, simulates yield and builds the financial case for all three routes: self-investment, ESCO and renewable purchase through DPPA.
0867 831 368•solar@orcaenergy.vn
Request a consultation