Micro inverter vs string inverter: a comprehensive comparison

Micro inverter vs string inverter, the same applies to distributed photovoltaic projects, but its product topology and circuit design has a fundamental difference. There was a previous discussion on microinverter vs optimizer if anyone is interested. In this article, we will take a look at micro inverter vs string inverter to see what the specific differences are.

1. What is a micro inverter?

Micro inverter convert the DC power generated by individual solar panels in a solar PV system into the AC power required by the grid and household appliances. Micro inverters are mounted directly behind each solar panel. This decentralised structure enhances system performance and allows panel-level tuning when shading or panel mismatch issues occur.

Microinverters consist of semiconductor devices, such as insulated-gate bipolar transistors or metal-oxide-semiconductor field-effect transistors, which facilitate the conversion process. They also include capacitors, transformers, and other passive components to regulate voltage and ensure efficient power conversion.

About photovoltaic microinverter we have previously compiled the best top 5 solar microinverter companies in the world, you can click to view.

2. What is a string inverter?

A string inverter, also known as a centralized inverter, is another type of device used in solar PV systems to convert DC power from multiple solar panels connected in series into AC power. Unlike microinverters, string inverters are connected to an entire string of solar panels and are installed in a central location, typically in an inverter box or on a wall. This configuration simplifies installation and reduces wiring complexity, as only one inverter is required for the entire array.

In order to convert the entire DC voltage of the solar panels in a string into AC voltage, string inverters use a single conversion step. Additionally, monitoring capabilities may be limited compared to microinverters, as they typically provide aggregate data for the entire array rather than individual panel-level insights.

图片

3. What is the difference between micro inverter vs string inverter?

The input of microinverter is designed as single-component independent or component parallel input structure, while the input of string inverter is designed as multi-component series input structure, so the microinverter and string system are quite different in terms of operating voltage, comprehensive system efficiency, operation and maintenance mode and installation location:

3.1 working voltage

Microinverters: The photovoltaic modules in the microinverter system are connected in parallel, and the system operates without voltage superposition between the modules, and the DC voltage does not exceed 120V.

String Inverters: When the system is in operation, the whole string line voltage accumulation can generally reach 600V~1000V.

3.2 structure

Microinverters: Each solar panel has a compact device mounted behind it.

String Inverters: String inverters are mainly used for small and medium-sized rooftop photovoltaic power generation systems, small ground power stations.

3.3 application

Microinverters: Perfect for systems with intricate roof patterns, problems with shading, or changes in panel orientation.

String Inverters: Ideal for panels oriented consistently and with little shading in systems.

3.4 power

Microinverters: Produce less power per unit on average than string inverters.

String Inverters: Able to manage the full array of solar panels, they provide a higher power output per unit.

3.5 installation

Micro inverter: with modular design, small volume and light weight, it can be directly installed on the PV racking, plug and play, basically not independently occupy the installation space. In addition, the number of inverters can be selected according to the actual demand when the system is expanded and transformed to realize flexible expansion.

String inverters: connected in series with each "string", generally installed in the vicinity of a string of components below the use of fixed brackets or hoop mounting equipment fixed to the column, or can be installed on the adjacent wall.

图片

4. Pros and cons of micro inverter vs string inverter

For your solar energy system, it's critical to carefully consider the benefits and drawbacks of both alternatives before deciding between micro inverter vs string inverter. An outline of the benefits and drawbacks of micro inverter vs string inverter is provided below:

4.1 string inverter pros and cons

Pros:

Easy to troubleshoot: Since string inverters only have one inverter per system, troubleshooting is made easier with them. Problem solving and troubleshooting are easy enough, requiring little technical knowledge.

Low cost: string inverters are often less expensive than microinverters, which makes them a desirable choice for customers on a tight budget.

Simple system design: The small size and light weight of string grid-connected inverters make them easy to handle and install. They do not require specialized tools and equipment, nor do they require a dedicated power distribution room, which simplifies construction and reduces the footprint in a variety of applications.

Efficiency in shade or single-panel issues: Although shading can impact a string inverter system's overall performance, certain models are effective at doing so.

Wide MPPT voltage range: The MPPT voltage range of string inverter is wide, generally 250-800V, the component configuration is more flexible, and the power generation time is long in rainy days and foggy areas;

图片

Cons:

Inverter issue impacts entire system: If there's a malfunction or issue with the string inverter, the entire solar energy system may be affected, leading to a complete shutdown until repairs are made.

Power devices with small electrical gap: not suitable for high altitude areas, outdoor type installation, wind and sunlight can easily lead to shell and heat sink aging;

Panel-level impact: Issues with one panel can impact the energy production of other panels connected to the same string, affecting overall system performance.

4.2 micro inverter pros and cons

Pros:

Easy system expansion: Microinverters allow for easy system expansion, making them suitable for adding more solar panels to an existing setup.

Panel-level monitoring: Microinverters provide panel-level monitoring, enabling users to monitor the performance of each solar panel individually.

Allows for complex system design:Microinverters provide flexible installation and are ideally suited for intricate system designs that have panels on several roof faces.

Individual panel performance doesn't impact others: In a microinverter system, problems with one panel do not impact the operation of other panels, in contrast to string inverters.

Meets rapid-shutdown requirements: Microinverters meet rapid-shutdown requirements without the need for additional equipment, simplifying installation and compliance.

图片

Cons:

Difficult to repair: Identifying and repairing issues with microinverters can be challenging, requiring specialized knowledge and technical expertise.

High price of microinverters: Microinverters cost more compared to both centralized inverters and string inverters.

More points of failure: Numerous components in microinverter systems mean that there are more possible sources of failure, which raises the need for maintenance.

Few application scenarios: Microinverters are generally suitable for rooftop home use, and applications are limited.

While there are benefits and drawbacks to both micro inverter vs string inverter, the decision ultimately comes down to elements like system design, shading circumstances, financial constraints, and monitoring preferences. To find the ideal solution for your unique demands and objectives, it is imperative that you speak with an expert in solar energy.

5. Are micro inverters safer than string inverters?

Strict safety requirements are met in the design of both micro inverter vs string inverter. However, microinverters may offer an added layer of safety by limiting the voltage to that of a single solar panel, reducing the risk of high-voltage DC arcs. Additionally, microinverters' decentralized design minimizes the impact of a single-point failure on the entire system, enhancing overall safety.

6. Are micro-inverters more efficient than string inverters?

Microinverters tend to be more efficient than string inverters in systems with shading or panel-level variations. This is so that the effects of shade or mismatch problems are lessened on the system as a whole. Microinverters maximise the performance of each panel independently. Nonetheless, the difference in efficiency between the two could be negligible under perfect circumstances with consistent exposure to sunlight.

图片

7. Micro inverter vs string inverter: Which is best for your home?

The decision between a string inverter and a micro inverter is influenced by a number of variables, such as budget, shade preferences, and roof design. Microinverters could offer improved monitoring and performance for properties with complex roof designs or shading issues. Conversely, simpler installations with steady exposure to the sun can be a better fit for string inverters. To find the ideal solution for your home energy storage or place of business, it's critical to assess your unique needs and speak with a solar energy specialist.

8. Are micro inverters more expensive than string inverters?

Microinverters typically have a higher upfront cost per watt compared to string inverters due to their individual panel optimization and monitoring features. However, the total cost of ownership over the system's lifespan may vary depending on factors such as system performance, maintenance requirements, and warranty coverage. For your solar energy system, it is critical to weigh the immediate expenditures as well as the long-term advantages of microinverters against string inverters.

图片

The above two inverter products have their own suitable segmentation application scenarios and application advantages, when comparing the selection of micro inverter vs string inverter, the right type of inverter should be selected according to local conditions.

String inverters have become the main choice in the distributed PV market due to their mature and reliable technology and low-cost advantages, while microinverters are also decreasing in cost per watt with the support of technological progress. As the industry puts forward higher requirements for the safety, system efficiency and intelligent operation and maintenance of PV power plants, microinverters will be used more often.

If you are interested in inverter comparison articles you can check out Renogy inverter vs TYCORUN inverter, high frequency inverter vs low frequency inverter. Hope you get useful information from them.