Solar inverter would do the important task of converting your solar power into usable alternating current. Here’s how to choose the right solar inverter for your home.
Solar inverters are a crucial part of your photovoltaic system. They convert the direct current from your photovoltaic panels into the alternating current that your home uses. They’re tucked away and less prominent than solar panels. However, they’re just as important to the operation of your system. It’s worth taking the time to understand the different types and tradeoffs. This knowledge will help you make the right choice.
What does a solar inverter do, exactly?
Direct current is electricity that flows in one direction. It’s the type of electricity used by batteries and portable electronics, like your phone and laptop. This is what your solar modules produce, but your home can’t use DC power directly. The North American electric grid uses alternating current (AC) at 60 hertz. This means that it switches direction 60 times a second.
It’s the job of the solar inverter to perform this DC-to-AC conversion.
Why Do We Need a Solar Inverter?
Solar panels generate direct current (DC) electricity. In DC, electrons flow steadily in one direction. However, nearly all household appliances, lighting, air conditioners, refrigerators, and TVs operate on alternating current (AC). This means the current periodically reverses direction, typically 50 or 60 times per second depending on the country. The utility grid itself also operates on alternating current.
The solar inverter’s primary job is to bridge this gap. It converts the variable DC power from the solar panels into clean, grid-compatible AC power.
The Basic Working Principle
Prostar solar inverters perform the DC-to-AC conversion using high-speed electronic switching rather than old mechanical methods. Here’s how it happens step by step:
DC Input from Solar Panels
Sunlight hits the photovoltaic cells → electrons are excited → a DC voltage is produced. (usually 250–600 V or more in strings of panels, depending on the system design).
DC Conditioning & MPPT
The incoming DC is not constant — it varies with sunlight intensity, temperature, shading, and panel angle.
Almost all good solar inverters use MPPT. This is an intelligent algorithm that continuously adjusts the electrical load. It extracts the absolute maximum power from the panels under any conditions.
This step can improve energy harvest by 15–30% compared to a system without MPPT.
High-Frequency Switching (The Core Conversion)
The inverter uses powerful semiconductor switches — typically IGBTs or MOSFETs — arranged in an H-bridge configuration.
These switches turn on and off extremely rapidly (thousands to tens of thousands of times per second).
The inverter precisely controls the timing and pattern of switching. By doing so, it creates a pulsating waveform that alternates direction. This process effectively turns steady DC into AC.
Waveform Shaping → Pure Sine Wave
The raw switched output is not yet perfect.
Filters such as inductors and capacitors smooth the waveform. Advanced modulation techniques, most commonly PWM, refine it into a clean pure sine wave.
This wave matches the grid’s voltage and frequency.
Synchronization & Grid Interaction
Grid-tied inverters constantly monitor the utility grid’s voltage, frequency, and phase. They synchronize their output to be perfectly in step with the grid (this is called “grid-following” behavior).
If the grid goes down, most standard inverters shut off automatically for safety (anti-islanding protection). Hybrid inverters can disconnect and form a microgrid with batteries.
Output & Additional Functions
The AC power can now:
- Power your home appliances directly
- Feed excess energy back to the utility grid (net metering)
- Charge batteries (in hybrid/off-grid systems)
Types of solar inverters
In addition to doing DC-to-AC conversion, inverters for PV systems must manage electricity flow. They are interconnected to the electric grid like most home systems. They regulate the flow to and from the grid. These are called grid-tie inverters. As the name suggests, grid-tie inverters allow your photovoltaic system to seamlessly connect with the grid. They provide clean, uninterrupted power regardless of how much or little power your panels generate.
Think of the different situations that can occur. Your panels may be producing more electricity than your house is using. In that case, you have to send power into the grid. You might be producing only some of your power needs. Your house is partly powered by solar and partly by the grid. Or it might be nighttime, and all of your power is coming from the utility. It’s the job of a grid-tie inverter to handle all of these scenarios without so much as a light flickering.
There are also off-grid inverters that are used with battery systems and do not connect with the grid at all. These are outside the scope of this article.
There are a few major types of grid-tie inverters available. Choosing an inverter is one of the important product decisions you’ll make, so it’s important to get familiar with these.
String inverters
Solar panels on your roof are wired together in one or more “strings.” These strings can be connected to a type of inverter. This inverter handles the power output from all of them. This type is called a string inverter, and is the least expensive option.
Lower cost does come with some drawbacks, however.
String inverters suffer from a problem. A power drop in one panel causes power to drop across the entire string. Shadows from numerous things could cause a power drop. These include a chimney, nearby buildings, trees, and leaves. Soiling from dirt or birds could also be responsible. Or, it could also be caused by a faulty panel.
These are the most common type, connecting multiple solar panels in series (a string). They are cost-effective but can be less efficient if one panel is shaded or malfunctioning.
Power Optimizers
A power optimizer-based inverter system is like a string inverter. It has an MPPT unit, or power optimizer, attached to the back of each solar panel. With this setup, each panel has its own power optimizer. A power drop at one panel affects only that panel. It does not impact the rest of the system. This mitigates the major flaw of string inverters.
Power optimizers also give you panel-level monitoring. You can see the power output of each panel. This allows you to know if there are problems with any of them.
The cost of this type of system is higher than a regular string inverter. However, it is generally not as high as microinverters.
Hybrid Inverters
A hybrid inverter is a type of string inverter that incorporates a charge controller for managing a battery system. You can purchase a charge controller as a separate unit. A hybrid inverter, however, offers the convenience of an all-in-one device. Apart from that, it has the same characteristics as a standard string inverter.
Solar inverter efficiency
When inverters perform the DC-to-AC conversion, there’s always a little bit of energy that is lost as heat. Cheap DC-to-AC inverters, like the type that plug into your car’s 12v socket, can have very poor efficiency. However, solar inverters from popular manufacturers are highly efficient.
Related Solar Inverter
Main Types of Solar Inverters
| Type | Where Conversion Happens | Pros | Cons | Best For |
|---|---|---|---|---|
| String Inverter | One central unit for many panels | Lower cost, simple, mature technology | Single point of failure, shading affects whole string | Simple roof systems, no shading |
| Microinverter | One tiny inverter per panel | Panel-level MPPT, excellent shading tolerance, module monitoring | Higher upfront cost, more components | Shaded/complex roofs, small systems |
| Power Optimizer + Central Inverter | Optimizer per panel + central inverter | Panel-level optimization, good price/performance balance | Still requires central inverter | Moderate shading, larger systems |
| Hybrid Inverter | Supports batteries + grid | Battery backup, future-proof, time-of-use optimization | More expensive | Systems with storage or blackout protection |
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