Photovoltaic inverter repairs

A solar inverter, also known as a photovoltaic (PV) inverter, is the central component of every PV installation. It is responsible for converting direct current (DC) generated by photovoltaic modules into alternating current (AC) that complies with the parameters of the power grid. In addition to its primary function of energy conversion, the inverter also performs a range of control and safety tasks – it monitors system parameters, synchronizes with the grid, optimizes energy efficiency, and logs operational data.

Photovoltaic inverters can be classified according to several key technical criteria: the type of PV installation, the power rating of the device, and the number of output phases. Understanding these categories is essential during both the design and maintenance of photovoltaic systems.
 

1. Based on the type of PV installation

• On-grid inverters (grid-tied): Operate exclusively in systems connected to the public power grid. They convert energy from PV panels and feed it into the grid or supply local loads. They cannot operate without grid voltage (anti-islanding function).
• Off-grid inverters (stand-alone): Designed for autonomous systems, independent of the utility grid. They work with energy storage systems and often with generators, allowing full power supply in remote or off-grid locations.
• Hybrid inverters: Combine the functionality of both on-grid and off-grid systems. They can export power to the grid, store surplus energy in batteries, and switch to island mode in case of grid failure.

2. Based on power and system architecture

• Microinverters: Convert DC to AC directly at each PV module. They allow independent operation of each panel, which minimizes energy losses due to partial shading or soiling.
• String inverters: Handle multiple PV modules connected in series (a string). This is the most commonly used type of solar inverter in commercial and industrial systems.
• Central inverters: High-power units used in large-scale solar farms. They manage hundreds of PV modules and control the entire installation from a single unit.

3. Based on the number of phases

• Single-phase inverters: Typically used in small-scale systems (up to 3–6 kW) where energy is supplied via a single-phase network.
• Three-phase inverters: Designed for higher power demand and better grid stability. They distribute the load more evenly and ensure improved performance of the PV system.

Due to continuous operation in varying environmental conditions, solar inverter components are exposed to wear, overheating, voltage fluctuations, and external factors such as moisture, dust, or lightning-induced surges. Common signs of failure include error messages, loss of grid synchronization, unexpected shutdowns, or lack of communication with the monitoring system.
 

The most frequent issues encountered during photovoltaic inverter service include:

• Power module failures (IGBTs, MOSFETs) – caused by overheating, voltage spikes, or overload
• Degradation of electrolytic capacitors – leading to reduced performance or random restarts
• Cooling system and fan failures – causing thermal shutdowns
• Communication errors – related to firmware faults or damaged communication modules
• Short circuits and surges on the AC/DC side – affecting terminals, relays, and fuses

From a service perspective, every solar inverter fault requires a dedicated diagnosis and load testing to determine the root cause and scope of repair.

Photovoltaic inverter repair should be performed by specialized companies with the appropriate technical facilities, experience in power electronics, and dedicated test equipment.
 

Key aspects of the repair process include:

• Service response time – fast diagnostics and repair are crucial to minimize energy losses and operational downtime
• Comprehensive diagnostics, including voltage measurements, component testing, and system error analysis
• Precise replacement of faulty components, such as transistors, capacitors, or communication modules
• Functional testing under realistic operating conditions on dedicated test benches
• Full-device warranty, regardless of the scope of repair performed

For companies in the PV industry, partnering with a reliable service provider for solar inverter repair helps reduce costs, shorten downtimes, and extend the overall lifespan of photovoltaic installations.

At ADEGIS, we specialize in:

1. Repair of hybrid and string inverters from Huawei
2. Repair of string, hybrid, and central inverters from Sungrow
3. Repair of photovoltaic inverters with optimizers from SolarEdge
4. Repair of string and hybrid solar inverters from Fronius
5. Repair of string and hybrid inverters from Growatt
6. Repair of string, hybrid, and off-grid PV inverters from GoodWe