As countries worldwide accelerate their push toward “dual-carbon” goals, photovoltaics (PV) are taking center stage in the global energy transition. In 2024 alone, around 530 GW of new PV capacity was added worldwide, with China contributing 277.6 GW — a 28.3% year-on-year increase.

At the heart of every PV system lies the inverter, the device that converts solar power into usable electricity. Inverters are generally divided into two categories: centralized and string. Over the past decade, string inverters have emerged as the mainstream choice, offering flexibility, adaptability, and strong potential to reduce both upfront investment and the levelized cost of energy (LCOE). By 2024, string inverters accounted for roughly 80% of global shipments, far ahead of centralized units at just 20%.

As deployment expands across residential rooftops, commercial and industrial systems, and large-scale ground plants, string inverters are evolving at an unprecedented pace. This article reviews the key technology trends and application developments shaping the market as we move into 2025.

The Core Driver: Lower Costs, Higher Efficiency

The demand for cheaper, more efficient PV systems continues to push string inverter technology forward. Three trends stand out:

1. High Voltage and High Power

Mainstream string inverters have transitioned from 1,100 V to 1,500 V DC input platforms, cutting current, raising conversion efficiency, and reducing costs. The next step is 2,000 V and beyond. Some manufacturers are already rolling out solutions in the 2,000 V / 400 kW+ range, driving down balance-of-system (BOS) costs even further.

Alongside voltage gains, power density is rising. By 2030, large-scale string inverters are expected to reach 365 kW per unit, with power density climbing from around 2.76 kW/kg in 2024 to over 3.5 kW/kg. That means more power output at lower manufacturing cost.

2. High DC/AC Overload Ratios

Pushing DC input power higher than the inverter’s rated AC power — the “overload ratio” — allows systems to maximize annual output and cut LCOE. Mainstream models now exceed 130%, while leading solutions hit 160% or more, thanks to wide MPPT voltage ranges and intelligent dynamic derating that adjusts output in real time.

3. Topology Innovation

To handle higher voltages and boost efficiency, three-level topologies (such as NPC and ANPC) have become standard in high-power inverters. At 2,000 V and beyond, research is moving into five-level and multi-level designs, further improving waveform quality, reducing stress on devices, and lowering losses.

Reliability as the Lifeline

PV plants operate in tough, variable conditions — which means inverter reliability is non-negotiable. Advances are focusing on safety, protection, and predictive maintenance.

1. DC Arc Fault Detection and Interruption (AFCI)

Arc faults are a major fire risk. The latest string inverters use advanced sensors and AI-driven algorithms to achieve near-perfect detection rates and extinguish arcs in under 500 ms. Challenges remain in long-cable and high-current scenarios, but detection accuracy is improving rapidly.

2. Structural Safety and Explosion-Proof Design

Outdoor inverters typically achieve IP65 or higher protection. To address risks from internal faults, new designs combine reinforced enclosures with intelligent pressure relief — such as predefined rupture paths and venting channels — to safely release pressure without sacrificing sealing.

3. Intelligent Monitoring and Predictive Maintenance

Instead of reacting after faults, inverters are shifting to predictive models. Using precise insulation monitoring, temperature sensing, and capacitor health checks, combined with edge/cloud AI algorithms, operators can identify risks early and carry out preventive maintenance.

Value Expansion: Control and Smart O&M

As renewable penetration rises, inverters are becoming active participants in grid stability and plant operation.

1. Grid-Forming Capability

Advanced control strategies — such as Virtual Synchronous Generator (VSG), droop control, and Virtual Oscillator Control (VOC) — allow string inverters to provide inertia and damping in weak grids. Some 320 kW+ units can now operate stably at SCR ≥ 1.1 and even deliver black-start capability. The next frontier is fault ride-through and interoperability across different strategies.

2. Power Quality and Harmonic Suppression

Using fast DSPs, optimized modulation, and active filtering, modern string inverters can keep total harmonic distortion (THDi) below 3%, even under complex grid conditions.

3. AI-Driven O&M

AI is transforming operations: minute-level forecasting, second-level IV curve scans, and AI-based fault recognition all help operators run plants more efficiently. The challenge now is integrating diverse data sources — from weather and grid data to module imagery — into actionable insights.

Industry Foundations: Semiconductors and Localization

Performance gains depend on breakthroughs in core components — and in supply chain security.

1. Silicon Carbide (SiC)

SiC MOSFETs boost efficiency above 99%, increase power density, and reduce cooling needs. High costs limit use to premium models today, but rapid capacity growth and cost reductions will drive broader adoption.

2. Gallium Nitride (GaN)

GaN is already used in microinverters and auxiliary circuits, with engineering trials underway in higher-power applications. As costs drop and voltage handling improves, GaN will play a bigger role.

3. Localization

China is rapidly closing the gap in IGBTs, SiC modules, and control chips. By 2024, localization rates hit nearly 40% for 1,500 V string inverter power modules. Domestic MCUs are also gaining traction in mid- and low-power products. Localization strengthens supply chain resilience and cost competitiveness.

Conclusion

The string inverter industry is in a period of accelerated innovation. High-voltage platforms, advanced control strategies, predictive O&M, next-generation semiconductors, and localized supply chains are converging to deliver higher efficiency, lower costs, and greater reliability.

Looking ahead, string inverters will not only consolidate their dominance over centralized designs but also become central to new scenarios: commercial rooftops, residential PV, and PV-plus-storage systems. With their evolving intelligence and grid-support capabilities, string inverters are moving from passive power converters to active energy managers.

For Ginlong (Solis) Technologies and other Chinese manufacturers at the forefront of these developments, the opportunity is clear: lead in technology, scale globally, and make a lasting contribution to the world’s clean energy transition and the achievement of dual-carbon goals.

Solis has been working in the field of string inverters for 17 years and is committed to providing customers with the highest quality products and services.

As the core component of any solar PV system, the inverter is one of the main contributing factors of system revenue. Focusing on quality and reliability Solis is committed to providing high quality products and solutions for all application scenarios.

Quality components directly determine inverter life

Reliability and service life of an inverter is closely related to the quality of its components. The use of high quality components directly effects the performance of the inverter.

Solis maintains strong relationships with world-renowned component suppliers to ensure the stable supply of high-quality componentry and consistent product reliability.

Design and testing are the key to reliability

Investment is made in stress testing equipment which simulates extreme temperatures, humidity, wind, sand, rain, and salt spray encountered by an inverter in outdoor environments. Testing in this way ensures the reliability of the inverter can be evaluated and improved for ongoing product optimization.

Adaptable to extreme temperatures

Variation in temperature will affect the efficient working of an inverter and can be caused by regional differences, day to night, seasonal change, etc. The internal components of the inverter itself will also cause temperature variation which can all effect the long-term safe & efficient operation of the inverter.

Solis product design considers the impact of temperature changes and adopts various measures such as single-board concentration, coating protection, and internal fan cooling to protect the inverter. Solis design engineers verify the performance of the entire machine through thermal cycling, damp heat, humidity, freezing,powered Thermal Cycling, High temperature & rain tests to identify any defects in the inverter’s internal electronic components.

Excellent outdoor adaptability

Other factors brought about by external field exposure, such as UV, salt spray, humidity, sand and so on can affect inverter efficiency and life. Strong environmental adaptability is crucial to the reliable operation of the inverter. Solis-(100-125) K-5G series inverters have IP66 protection and C5 anti-corrosion, and have excellent outdoor adaptability.

All Solis new products are powered on and run for more than 180 days in our exclusive test area. The status of the inverter is monitored daily via SolisCloud, to observe the main parameters of its power generation and internal temperature.

Comprehensive product quality control

R&D – production – testing – sales – service. This is a complete vertically integrated product supply chain; another unique advantage of Solis. Comprehensive product quality control through the flow and exchange of information at each stage, effectively ensures the reliability of the inverter is guaranteed.

Solis has a world-class design team and a brand new 40GW capacity manufacturing facility with automated digitalized product lines. It has the capability to test the reliability of all its products in all environmental scenarios.

We are happy to present Central Vs String Inverters in Big Utility Scale Power Plants Webinar

When: May 31, 2021 04:00 PM IST

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Confirmed Speakers:

On Friday 6 November the Indian solar industry witnessed GoodWe’s nationwide launch of the much anticipated HT Series. The Suzhou-based multinational is widely recognized as a global leader in Commercial & Industrial projects but has recently been adding to its Utility portfolio with larger and more powerful solutions. The event, held at the Pullman resort in New Delhi, was attended by prominent figures of the Indian solar industry and offered an insight into what other projects GoodWe might set its sight on.

Product unveiling ceremony followed by detailed product presentation by Mr. Vivek Bhardwaj, Head of Sales – India, and a panel discussion featuring Mr. YBK Reddy (SECI), Mr. Bimal Jindal (SB Energy), Mr. Priyatosh Pathak (O2 Power), Mr. Gaurav Wadhwa (Renew Power), Mr. Syed Naqvi (ACME) and Mr. Sudhir Pathak (Hero Future Energies), and moderated by Mr. Vinay Rustagi (MD – Bridge to India)

During the panel discussion, Mr. YBK Reddy, DGM – Solar (SECI) highlighted that demand for power is projected to reach 300GW in India and that the government has plans for hybrid tenders involving solar and other sources of renewable energy in its energy matrix. It is expected that more efficient component products and more reliable system solutions will be required to meet the demand.

GoodWe seems to have anticipated many of these demands and the success of its launch of the 1500V String Inverter was seen by many as the moment of truth. The new HT series is said to provide the lowest levelized cost of electricity (LCOE) and the industry’s most advanced safety features.

The debate at the Pullman resort touched on various trending topics including the long-standing Central vs String inverter comparison and the challenges and opportunities presented by the “600+ wafer era”.

Mr. Vivek vows that HT Series 1500V 250kW PV inverter will be the safest and most intelligent inverter of the time with added safety features, 12 MPPT design, compatibility with latest technology and high power PV Modules with DC input current of 15A, and owned advanced monitoring system for 24Hrs remote monitoring and O&M functionality.

String Inverters VS Central Inverters

Mr. Gaurav Wadhwa stressed that string inverters are the better choice and present advantages related to BoS costs. Adding to the point, Mr. Sudhir Pathak mentioned how less space is now being used with increased block sizes in the latest PV project designs. Pathak also added that this the logical pathway for string inverters to follow; to be more compact and more intelligent than ever for utility projects.

The Era of High-Power PV Modules

In terms of technological trends, the “Big” Era is now here with PV modules’ power moving from 500W to 600W+. At the HT product launch in New Delhi, Mr. Syed Naqvi agreed that increasing wafer sizes and number of wafers in PV modules represents a challenge for inverter manufacturers and increasing the current rating of PV module also requires inverter technology to go up one gear. In this aspect GoodWe also seems to have anticipated this trend, as reflected in its new product offering. The 1500V 250kW is said to be highly compatible with the latest high-power PV modules and bi-facial modules, allowing DC input currents of 15A.

GoodWe received congratulatory wishes from industry leaders and GoodWe’s vision for 2021 already presents sizeable investment opportunities and will likely play a key role in the country’s additional installed capacity targets for the 2021-2025 period.

This is the first utility scale PV plant in India uses high efficiency Mono PERC solar modules, fixed-tilted PV panels with a tilt angle of 15° due south and flat panel and Huawei FusionSolar 1500V smart string inverter. Especially this year, Huawei updates the traditional astronomical algorithm and adopt intelligent trackers based on AI algorithms to achieve the integration of tracker control and power supply, maximizing energy yields.

It’s worth mentioning that the SUN2000-95KTL-INH0 (“95KTL”) 1500Vdc smart interactive string inverters are used in this project. It’s a ground-breaking design in inverter technology, offering 12 strings intelligent monitoring and fast trouble-shooting, 6 MPPT per unit, effectively reducing string mismatch, maximum efficiency 99.0%, European efficiency 98.8%, PLCC (Power Line Carrier Communication) and Smart I-V Curve Diagnosis supported, no vulnerable parts like fuses and LCD, protection degree of IP65, high availability, high uptime and low O&M (“operation and maintenance”) cost. With the PLCC technology, no RS485 cables is required, which delivers a simpler system with safer and more reliable data transmission.

Pavagada Solar Park is located on the flat terrain with high radiation and very little rainfall. It’s part of Karnataka’s Solar Policy 2014-2021, which aims to shift the dependency from conventional power resources to eco-friendly energy resources. Huawei is very grateful to announce that string inverters have been installed on 3.5 GW of PV plants in India till this April. It’s honored to get together with ReNew Power passing the benefits of clean energy to everyone.

About ReNew Power:

ReNew Power Limited is India’s largest renewable energy IPP (Independent Power Producer) in terms of total energy generation capacity. As of February 2019, ReNew had a total capacity of over 7 GW of wind and solar power assets across the country, including commissioned and under development projects. It develops, builds, owns and operates utility scale wind and solar energy projects as well as distributed solar energy projects that generate energy for commercial and industrial customers. ReNew has a strong track record of organic and inorganic growth having nearly doubled its operational capacity in each of the last three Fiscal Years. ReNew’s broad base of equity investors include Goldman Sachs, JERA, ADIA, CPPIB, and GEF SACEF India.

Source: huawei