Amid the exponential growth of AI computing power demand, the power density of single cabinets in intelligent computing centers continues to soar. High-end chips such as H100/H200 have a power consumption of 700W, while the GB200 exceeds 2700W. The accompanying heat dissipation pressure and transmission losses have made traditional power supply architectures unsustainable. Against this backdrop, the Solid State Transformer (SST), based on fully controlled power electronic devices and high-frequency magnetic coupling technology, has emerged as a core equipment to support high-density computing clusters and build a new-type power system, ushering in a new era of power transformation characterized by “silicon advancing and copper retreating”.
Technical Core: Innovative Breakthroughs in Architecture and Principles
The core innovation of the solid state transformer lies in subverting the electromagnetic induction principle of traditional power frequency transformers, realizing efficient power conversion and intelligent regulation through power electronic conversion technology and high-frequency magnetic coupling. Its topological structure adopts a modular three-stage design, divided into medium-voltage stage, isolation stage and low-voltage stage from top to bottom. The physical structure corresponds to a complete link of medium-voltage side input filter cabinet, central power electronic cabinet, high-frequency transformer, low-voltage side power unit and output cabinet, forming a closed-loop system from input to output.
As the latest evolutionary form of data center power supply systems, SST uses wide-bandgap semiconductor devices such as silicon carbide (SiC) as the core to directly achieve efficient conversion from 10kV AC to 800V DC, completely replacing traditional power frequency transformers and multi-stage power distribution links. This “silicon advancing and copper retreating” technical path not only simplifies the power supply link, but also endows it with bidirectional intelligent and controllable energy flow capacity, making it a key supporting equipment for the “source-grid-load-storage” integrated architecture. It is compatible with 750-800V DC bus voltage and can seamlessly connect existing UPS/HVDC equipment with new energy systems.
Compared with traditional schemes, the most prominent technical feature of SST is the “three-in-one” integration mode, integrating the functions of three traditional devices: transformer, power distribution cabinet and UPS. Its power conversion efficiency is as high as 98.3%, 2-3 percentage points higher than the traditional scheme. In terms of physical size, the length is reduced by about 60% compared with Eaton’s own traditional product scheme, greatly saving room space. At the same time, through air natural cooling design, it reduces the difficulty of system heat dissipation design, eliminates the oil filling step, and reduces pollution.
Core Characteristics: Dual Dimensions of Advantages and Challenges
(I) Overwhelming Technical Advantages
The advantages of solid state transformers are reflected in multiple dimensions such as efficiency, functionality and flexibility. In terms of power quality control, it can real-time regulate current, voltage and power, achieve constant frequency and constant voltage output, and the primary power factor is always close to 1.0. The 0.1ms-level response speed can quickly compensate for the power balance of the power system, effectively resist interference such as photovoltaic fluctuations, and greatly reduce harmonic pollution.
In terms of reliability and safety, SST does not require conventional relay protection devices and has the function of circuit breakers, which can turn off fault large current in microseconds. Cooperating with the remote online monitoring system, it can realize highly automated control of the power distribution network. Its modular design adopts mature semiconductor switching components and ZVS/ZCS soft switching technology, which not only improves power density, but also facilitates flexible expansion. The application of magnetic integration technology further compresses the module volume and makes system operation and maintenance more convenient.
In terms of energy compatibility, SST reserves interfaces for new energy access. In the future, it can seamlessly integrate photovoltaic, energy storage, charging piles and other equipment. Although it is mainly adapted to lithium batteries at present, it has laid the foundation for green power direct supply and distributed energy consumption. At the same time, its high-voltage DC output characteristics reduce the consumption of cables and busbar materials in the back-end transmission lines. If combined with DC-powered servers, it can further reduce the conversion link and improve the overall energy utilization efficiency.
(II) Current Development Bottlenecks
Despite its significant advantages, the solid state transformer is still in the semi-mature stage of technological iteration and market cultivation. The failure to achieve large-scale mass production leads to the lack of long-term verification of its reliability. The internal power electronic devices, capacitors and cooling fans are all potential fault points, and the fault frequency is higher than that of traditional transformers with simple structures.
High cost is the core factor restricting its industrialization. The cost in the trial production stage is about 4-7 yuan per watt, mainly due to the high price and limited production capacity of wide-bandgap semiconductor devices and high-frequency magnetic materials. In addition, the medium-voltage scenario has higher requirements for the voltage resistance level of components, and the circuit needs to be redesigned. The procurement cost of these special-specification components is high in the small-batch production stage.
The immature industry ecology also needs to be solved urgently: there is a shortage of load equipment adapted to 800V DC. Even Nvidia’s scheme needs to supply power to the load through 800V to 48V conversion; the maturity of DC protection components such as switches is insufficient, mainly relying on fuses and isolating switches; the shortage of professional operation and maintenance teams and the lack of mature operation and maintenance experience make the daily monitoring and fault handling of SST much more difficult than traditional transformers. In addition, its application and deployment need to obtain the cooperation of power grid companies and cannot be decided unilaterally, which also prolongs the landing cycle.
Application Scenarios: Value Implementation in Diverse Fields
At present, solid state transformers have been deployed and applied on a large scale in three core scenarios, all centered on the core goal of “improving energy efficiency and adapting to diverse power needs”, showing broad application prospects.
In the AC-DC hybrid distribution network, SST, as an “energy router”, realizes AC and DC power sharing the same distribution network and reduces the loss of multi-level conversion. Its functions such as bidirectional energy flow and flexible power flow regulation can increase the distributed energy consumption rate by more than 18%, improve the electric vehicle access capacity by 20%, and reduce the distribution network and microgrid network loss by up to 5%, which is crucial to improving the power grid reliability and renewable energy utilization rate.
In the green power direct connection scenario, SST undertakes the core role of “full DC step-up access” and builds a closed green power channel through dedicated lines. Photovoltaic and energy storage equipment can be directly stepped up through SST to provide direct supply services for large DC loads such as data centers, hydrogen production and electrolysis, getting rid of dependence on the AC power grid, minimizing power loss in intermediate links, and promoting the efficient utilization of green power.
In the field of electric vehicle charging stations, SST replaces traditional transformers and converter equipment to realize “chain power electronics”, providing a “four-pole” charging experience: extremely comprehensive (full functions of optical storage, charging and conversion, and full adaptation to vehicle models), extremely simple (15% space saving and 20% municipal power capacity saving), extremely fast (supporting MW-level charging, 100 kilometers of driving range in 1 minute), and extremely efficient (maximum efficiency ≥97.5%, 5% higher than traditional schemes), perfectly meeting the future upgrade of ultra-fast charging needs.
In addition, the application of SST in data centers is the most critical, becoming the core direction promoted by technology giants such as Nvidia, which can effectively support the stable operation of high-power density GPU clusters; in the field of rail transit, although there are limited cases at present, it has shown clear application potential with its efficient conversion and intelligent regulation capabilities.
Market Pattern and Industry Progress
(I) Market Scale and Competitive Landscape
The solid state transformer market is entering a period of rapid growth. The global sales volume reached 442 million US dollars in 2024, and is expected to soar to 1.747 billion US dollars by 2031, with a compound annual growth rate (CAGR) of 22.0% from 2025 to 2031. The global market is mainly concentrated in North America, Asia Pacific and Europe. The product types are mainly two-phase and three-phase solid state transformers, accounting for about 90% of the market share together.
The current market competition presents a pattern of “differentiated breakthrough”, and a stable competitive echelon has not yet been formed. Major participants include international giants such as ABB, Siemens and General Electric, as well as domestic and foreign enterprises such as Eaton, Vertiv, Delta, XD Electric and Sifang Electric. Due to the high price and limited production capacity of upstream components, and the high technical barriers in high-frequency topology and control system design, SST has not yet achieved large-scale industrialization, making it difficult to clarify the competitive pattern through market share.
(II) Domestic and Foreign Technical Progress
The overseas market started earlier and made faster progress in the field of SST. The US market is led by technology giants such as Meta, Nvidia and Google. As a leading enterprise, Eaton has achieved small-scale pilot trials, delivered three sets of equipment to 21Vianet in December 2024, and provided customized products for overseas customers such as Nvidia and Google to adapt to the US 13.8kV medium-voltage power grid standard. Prototypes of Vertiv, Delta and Schneider have been commissioned. Among them, Vertiv’s ±400V scheme is expected to supply Meta in the first quarter of 2026, and Delta has built a complete product line covering SST, Sidecar and 800V to 48V PSU.
The domestic market is currently in the stage of sporadic pilot trials, with less than 10 known cases, and the overall progress is slower than that overseas. The pilot project of 21Vianet data center participated by Eaton has been in operation for nearly a year; XD Electric’s 800V SST passed the expert appraisal in August 2025 and is waiting to enter the trial stage; Weiguang New Energy’s 1250KVA sample has been deployed in the building of its shareholder Baiyun Electric; enterprises such as Sifang Electric, Jinpan Technology and Zhongheng Electric have also launched relevant products or schemes. Among them, Zhongheng Electric is the only domestic manufacturer that has launched a complete 800V HVDC solution.
From the perspective of the industrialization timeline, it is expected that small-batch deployment of SST will be realized globally in the second half of 2026, and large-batch application will have to wait until the first half of 2027. It is worth noting that HVDC is a prerequisite for the promotion of SST. Nvidia Rubin plans to deploy HVDC in the second half of 2026. Only after the completion of high-voltage DC transformation can the large-scale application of SST be realized. Therefore, HVDC has become a key bottleneck link at the current stage.
Standards and Specifications: Exploration of Industry Standardization
At present, there is no unified industry standard for solid state transformers. While maintaining consistency in core directions, the product specifications of various manufacturers have differences in details. In terms of capacity specifications, mainstream products are in line with traditional transformers, and Eaton’s core specifications cover 1250KVA, 1600KVA, 2000KVA and 2500KVA; in terms of input voltage, the domestic standard is 10kV, while the US medium-voltage standard is 13.8kV; the output voltage forms a diversified pattern, with DC 800V and ±400V as the industry mainstream, 750V specifications adapting to IEC new energy standards, and 400V specifications meeting the needs of the North American market.
In terms of physical size, a mainstream product is 6 meters in length, 1.5 meters in depth and 2.2 meters in height, which is significantly reduced compared with the traditional scheme. Compared with another 800V HVDC scheme “Sidecar” in the industry, SST is different from the latter’s 400V AC input with 10kV AC input, and realizes “three-in-one” function integration, while “Sidecar” still needs to retain traditional transformers and power distribution cabinets, only replacing the AC UPS part, and the technical difficulty and value density are significantly lower than SST.
Future Trends: Technological Iteration And Ecological Improvement
The future development of solid state transformers will focus on three directions: technological optimization, ecological maturity and scenario expansion. At the R&D level, manufacturers will focus on improving the product line, developing product series combining standardization and customization for the power grid standards of different countries and diverse output voltage and power segment needs; at the same time, strengthen the practical application verification of new energy access functions and promote the in-depth integration of photovoltaic, energy storage and other equipment.
Cost control is a key breakthrough for industrialization. With the improvement of the production capacity of wide-bandgap semiconductor devices, the improvement of upstream and downstream supporting facilities, and the marginal effect brought by large-scale production, the cost of SST is expected to gradually decrease, promoting its transition from high-end pilot to popular application. In terms of the operation and maintenance system, the industry will gradually form mature operation and maintenance standards and professional teams, reducing the complexity of operation and maintenance through intelligent monitoring systems and improving the stability of equipment operation.
The formulation of industry standards will accelerate the process of market standardization. It is expected that unified technical specifications and test standards will be gradually formed in the next few years, guiding the market to transform from “differentiated breakthrough” to “standardized competition”. In terms of application scenarios, in addition to the existing data centers, distribution networks, charging stations and other fields, SST will achieve more breakthroughs in rail transit, industrial DC power supply and other scenarios, becoming an indispensable core hub in the new-type power system.
As an intersection of power electronic technology and the new energy revolution, the solid state transformer is not only a power supply solution to cope with the explosion of AI computing power, but also a key support for promoting energy transformation and building a green and low-carbon power system. With the continuous iteration of technology and the continuous improvement of the ecosystem, solid state transformers will surely play an increasingly important role in the global energy transformation, bringing more efficient, flexible and clean power guarantee to all walks of life.
