Types of Solar Inverters: Choosing the Right for Your PV System

Solar inverters play a key role in converting the direct current (DC) electricity generated by photovoltaic (PV) solar panels into alternating current (AC) that can power homes and businesses. With different technologies available, it’s important to understand the various types of inverters on the market to select the best match for your specific solar system needs.

String Inverters

String inverters are the most common and straightforward inverter option. As the name suggests, string inverters connect to an entire string, or series, of solar panels that are wired in sequence. All panels in the string will produce the same current level, and the inverter calculates the maximum power point for the whole string.

String inverters are typically installed centrally at the home or business and then connected to multiple solar panel “strings” through DC cabling. Their cost efficiency makes them well-suited for medium to large residential and commercial PV systems ranging from 5-10 kW up to 50kW or more in size depending on the inverter model. Maintenance needs are generally lower as well.

Microinverters

Rather than dealing with entire solar panel strings, microinverters work at much smaller individual panel-level granularity. Each microinverter is attached directly beneath its corresponding PV module, converting the unique DC output of that single solar panel only.

Not needing to match panel voltages, microinverters allow for panel-level flexibility in roofspace utilization. They also maximize energy harvest by independently optimizing the performance of each panel. However, their higher per-watt costs mean micros are usually only practical for smaller 0-10 kW residential systems or when module-level monitoring/control is crucial. Maintenance needs are also higher with more distributed components.

Power Optimizers

A newer type of module-level technology similar to microinverters are power optimizers. Unlike micros, power optimizers don’t actually convert DC-to-AC themselves. Instead, they condition each panel’s unique output to deliver maximum possible power by maintaining a consistent voltage level along an entire solar string which still utilizes a centralized string inverter.

This allows for many of the same panel-level benefits as microinverters like rooftop optimization and module-level monitoring, but at a lower upfront cost than micros since string inverters can still be used. The downside is optimizers alone don’t provide full DC-to-AC conversion, relying on a central inverter which requires more cabling and components.

Hybrid Inverters

Sometimes called “AC modules,” hybrid inverters pair traditional roof-mounted solar panels directly with integrated microinverters in a single weatherproof housing. This cuts down on hardware costs versus separate micros while retaining module-level maximum power point tracking (MPPT).

Like microinverters, hybrids provide flexibility and granular data but in a streamlined package ideally suited for smaller residential systems. Installation and setup are simplified compared to either micros or string inverters. Downsides include lack of aftermarket replacement options and optimization challenges for portioned shading conditions.

Choosing the Right Inverter Type

String inverters remain the most cost-efficient choice for medium and large commercial applications as well as residential installations with optimal sun exposure over 5 kW thanks to their full string-level optimization. Microinverters and power optimizers offer panel-level flexibility well-suited to shaded roofs or when module-level data is needed for smaller homes.

Hybrid inverters provide an elegantly simple package for rooftops under 10 kW with limited shading concerns. Consider breaker box capacity, roof layout uniformity, future expandability, and system monitoring/control priorities when comparing inverter types. Reputable brands like Enphase, SolarEdge, and SMA leverage the latest in microprocessor and power electronics engineering across all categories. With dynamic technology progress, the optimal inverter choice sometimes comes down to individual site factors and installation preferences. Consulting with a trusted solar pro is always advised before making final decisions impacting a system’s performance and lifespan for decades.

Enphase IQ Microinverters

Enphase is considered the earliest pioneer and market leader in microinverter technology. Their IQ series features IQ7+, IQ7X and IQ8 micros suited for residential and small commercial solar installations up to 60 kW. Enphase micros pair high reliability, safety, ease of installation and service with module-level monitoring/production visibility through the Enlighten monitoring portal. Warranties range from 25-30 years standard.

SolarEdge Power Optimizers and Inverters

SolarEdge takes the power optimizer approach to maximize panels independently while still using centralized string inverters. Their Power Optimizers connect each PV module to optimize performance, and their HD-Wave or HD-Wave inverters take DC inputs from multiple optimizer-enhanced strings to generate utility-grade AC power. The SolarEdge monitoring platform provides fine-tuned production insights. They offer a 25 year warranty across products.

SMA Solar Technology String and Hybrid Inverters

As a global inverter market leader, SMA produces many popular string and transformerless string inverters suitable for residential and larger commercial systems. Their TC1 microinverters pair directly with solar panels for easy hybrid installations as well. All SMA inverters emphasize high yields, ease of use, monitoring capabilities and compatibility with the Sunny Portal monitoring platform. Backed by a 25 year standard warranty.

Choosing an Installer

With the various solar technology options available today, consulting experienced installers is key for evaluating which system components like inverters make the most financial and practical sense per home. Relying on engineers with battery storage expertise can yield especially helpful insights regarding the evolving role energy storage will play as the solar-plus-battery market accelerates. Going solar is a major investment worthwhile researching thoroughly to ensure finding the best system value and performance through reliable local installers. Getting multiple quotes is also advisable to compare equipment and labor costs.

In conclusion, whether considering common string inverters, cutting-edge micros, optimizers or hybrid designs, understanding solar inverter technologies helps inform equipment selection appropriate for individual site needs now and in the future given solar’s evolving landscape. Consulting knowledgeable local installers remains critical to receive guidance on optimal inverter matches specific to property characteristics, budget and energy objectives for years of solar service.