CMSC has released a research report stating that under the trend of increasing power density in AI Data Centers (AIDC), NVIDIA has proposed an 800V DC architecture and indicated that Solid State Transformers (SST) may be the ultimate power supply solution. SST represents a highly integrated power electronics solution with advantages of small footprint and high efficiency. Its future penetration rate is expected to rise continuously, and it has broad application prospects in areas such as direct green power connection. Power shortages in North America may accelerate the industrialization of AIDC SST, and leading Chinese enterprises are positioned to achieve overtaking under this new power supply architecture.

The main viewpoints of CMSC are as follows:

**DC Power Supply Architecture for AIDC is a Trend, SST May Be the Ultimate Solution** AIDC server racks are evolving towards the megawatt level. Traditional multi-stage AC/DC conversion power supply methods suffer from issues like high losses, significant space occupation, and substantial copper losses. SST utilizes power electronics conversion and high-frequency transformers to directly convert medium-voltage AC power to 800V DC power. It offers prominent advantages in conversion efficiency and space utilization, while also enabling multi-port green power integration and modular rapid deployment, potentially making it the ultimate power supply solution for AIDC.

**SST Market Holds Vast Potential** Against the backdrop of power shortages overseas, there may be pressure to accelerate SST industrialization. Beyond the urgent demand for SST in large-scale AIDC facilities, its application prospects are also extensive in fields like direct green power connection, flexible distribution networks, electric vehicle charging, and rail transit, with many demonstration projects already underway domestically. According to calculations, the AIDC SST market could reach a scale of hundreds of billions, and when combined with other application scenarios, the potential is even greater.

**Power Electronics Companies are Accelerating SST Deployment** Following Delta and Eaton's launch of SST products targeting data centers, domestic power electronics companies have also introduced prototypes or announced increased R&D investments. Chinese enterprises possess deep expertise in power electronics and medium-voltage grid integration, positioning them to potentially achieve overtaking in the AIDC power supply iteration through forward-looking SST deployment. Currently, foreign companies are driving SST development towards higher voltage and power levels, while leading Chinese firms are also accelerating their upgrades.

**Power Devices and High-Frequency Transformers are Core SST Components** The SST topology consists of a medium-voltage rectification (AC/DC) stage and a medium-voltage isolated conversion (DC/DC) stage. The costs of power devices and high-frequency transformers account for approximately 40-50% and 15-20% of the total cost, respectively. Their cost and maturity are key factors influencing SST industrialization. Considering the voltage withstand limitations of power devices, the medium-voltage rectification stage typically employs a cascaded approach. However, cascading a large number of power electronic devices poses challenges to system reliability, requiring time for validation. As voltage levels increase for high-frequency transformers, difficulties arise in areas like insulation, partial discharge, and corona. Furthermore, downstream requirements often call for SST structures to be as compact as possible, and higher frequencies may lead to greater losses. Therefore, the design and manufacturing processes for high-frequency transformers are particularly critical.

**Solid-State Circuit Breakers are Key Protective Devices** Solid-state circuit breakers are power electronic switching devices offering advantages such as fast breaking speed, long lifespan, high reliability, and small size, aligning well with the development trends of AIDC SST power distribution architecture. Their technical barriers lie in power semiconductors, control algorithms, thermal management, and system integration. Leading overseas power equipment companies hold a technological edge, while domestic enterprises are leveraging supply chain advantages to accelerate market entry.

**Companies to Watch:** Sungrow Power Supply, Sifang Co., Ltd., China XD Electric, Jinpan International, Eaglerise Electric & Electronic, Hopewind Electric, Xinfengguang, Baiyun Electric, Jingquanhua, Xinte Electric, Liangxin Co., Ltd.

**Risk Warnings:** SST penetration may fall short of expectations, the supply chain may face bottlenecks, and AIDC demand may not meet projections.