As global solar installed capacity expands rapidly, demand for power devices in power conditioning systems (PCS) is growing steadily. Output ranges span from a few kW for residential applications to multi-MW utility-scale installations, and the appropriate use of Si IGBT, SiC MOSFET, and GaN-on-Si is becoming clearly defined by application. As designer options multiply, understanding the logic of device selection from a procurement perspective is directly relevant to evaluating the product competitiveness of suppliers.
The Scale of the Solar PCS Market — Context for Power Device Demand
Global solar installed capacity surpassed a cumulative 2 TW in 2024, with annual new installations exceeding 400 GW. Industrial and utility-scale systems (50 kW to several hundred MW) are the core of the market, and annual demand for power devices in large PCS has grown to a scale comparable to that of the EV market. With renewable energy policies continuing across countries, some forecasts project annual installations expanding to 500–600 GW by 2030, and the long-term stability of power device demand in this segment is high.
Device Selection Map by Output Range
For residential systems (1–10 kW), Si MOSFET or low-voltage GaN-on-Si is the mainstream choice. The relatively low system voltage (400–600 V) and the market characteristics of low-volume, high-mix production make cost the dominant selection criterion. For industrial systems (50 kW–1 MW), SiC MOSFET adoption is expanding rapidly, with high conversion efficiency and the ability to reduce heatsink size and installation costs being the key factors.
Residential (1–10 kW)
Si MOSFET or IGBT is mainstream. Cost sensitivity is high, and adoption of lower-cost Chinese-made devices is increasing. GaN-on-Si is beginning to appear in high-end models but mass-production cost remains a challenge. System voltage is predominantly 400–600 V, making 600 V-rated devices suitable. Cost pressure is intense due to competition with Chinese inverter makers (Huawei, SolarEdge, SMA, etc.).
Industrial (50 kW–1 MW)
Displacement toward SiC MOSFET is accelerating. The number of models achieving above 99% conversion efficiency is increasing, and cases where SiC is superior on a TCO (Total Cost of Ownership) basis including equipment cost are growing. The 20-year cumulative benefit from increased energy yield (efficiency improvement) frequently exceeds the price premium of SiC devices, making the ROI case viable.
Utility Scale (above 1 MW)
Multi-level topologies such as 3-level and 5-level are common, and Si IGBT remains the mainstream. However, modular SiC configurations and parallel module designs are increasingly adopted, and full-scale displacement is expected between 2026 and 2028. Simplified cooling systems and improved conversion efficiency are the designer motivations for SiC adoption.
Economic Rationale for SiC Adoption — ROI Calculation for Efficiency Improvement
The primary motivation for SiC adoption in solar PCS is improved conversion efficiency. While Si IGBT-based PCS typically achieve 97–98% efficiency, SiC MOSFET-based systems can achieve above 99% in some cases. This 1–2% efficiency difference accumulates over a 20-year equipment lifetime to represent a difference worth millions of yen in annual energy yield.
Example: 100 kW system, annual energy yield 120,000 kWh, electricity price of JPY 15/kWh assumed
- Improving efficiency from 98% to 99%: 1,200 kWh/year increase = JPY 18,000/year
- 20-year cumulative: JPY 360,000
Compared to the incremental SiC device cost per kW, the ROI for SiC adoption becomes viable more easily as system size increases. Particularly in cases where power producers operate equipment for long periods, lifecycle cost rather than initial cost becomes the primary evaluation framework.
Positioning of Major Device Suppliers
The four major SiC MOSFET suppliers are Wolfspeed, STMicroelectronics, Rohm Semiconductor, and ON Semiconductor. Wolfspeed is focused on expanding 8-inch SiC wafer manufacturing capacity and positions solar PCS module products as a priority. Rohm has built a track record with domestic PCS makers in Japan using 1200 V SiC MOSFETs for industrial applications.
Wolfspeed (SiC)
Leading in 8-inch wafer manufacturing, with a comprehensive lineup of 1200 V SiC MOSFETs. Offers discrete and module products for solar applications. Strong capability for long-term supply agreements, with a track record of direct contracts with large PCS makers.
STMicroelectronics (SiC)
The Master Series 1200 V SiC MOSFETs are widely adopted for solar applications. Broad lineup from AEC-Q101-compliant automotive products to industrial grades. Extensive supply track record with European PCS makers and a strong position in the European market.
Rohm (SiC)
An early mover with an established mass-production track record in SiC SBD and SiC MOSFETs. Gen4 products in the 1200 V range are available for industrial and solar applications, with deep design support infrastructure for domestic Japanese PCS makers.
Infineon (Si IGBT and SiC)
CoolSiC and CoolMOS cover the full output range for solar PCS. A key strength is the ability to provide consistent solutions from residential to large industrial scale. Designers face lower brand-switching costs when migrating from Si IGBT to SiC during the transition period.
Power Device Selection Criteria for Solar PCS Design
Operating Temperature and Reliability Specification Confirmation
Outdoor-installed PCS require operation across -40°C to +85°C. Requesting disclosure of power cycle testing and humidity resistance (85°C/85% RH test) data is the starting point for reliability evaluation. For salt damage environments (coastal installations), corrosion resistance is an additional requirement.
Evaluation Boards and Reference Designs
Suppliers that provide reference designs for solar PCS can substantially shorten design time. Whether this capability exists directly influences device selection among small and mid-size PCS makers. Having references organized by inverter topology (H4, H5, HERIC, etc.) makes adoption evaluation easier.
Long-Term Supply Commitment
Solar equipment has a service life of 20–25 years. Long-term supply guarantees (LTB/EOL notification policies) are an important procurement criterion for equipment manufacturers, so supplier policies should be confirmed. A minimum of 15 years of supply guarantee or at least 3 years of notice from an LTB (Last Time Buy) announcement is the industry standard expectation.
The Rise of Chinese PCS Makers and Its Procurement Implications
Chinese PCS makers such as Sungrow and Huawei Digital are growing their global market share. These makers are increasing the proportion of Chinese-made devices (primarily IGBTs) in their designs, and the dynamics with traditional European and Japanese device suppliers are shifting. For European and Japanese PCS makers to maintain competitiveness, differentiation through SiC-driven high efficiency and miniaturization is essential, and technical collaboration with device suppliers is becoming critical.
The implication for procurement professionals is that a customer's (PCS maker's) competitiveness is directly linked to device selection. The technology roadmap of the device supplier affects the next-generation product competitiveness of the PCS maker. Consequently, what device suppliers can offer PCS makers is not just "components" but "design knowledge and efficiency improvement proposals" — and the quality of the technical partnership is becoming a defining factor in the commercial relationship.
Power devices for solar applications represent a segment with stable long-term demand as global renewable energy investment continues to expand. In the industrial segment above 100 kW where SiC displacement is underway, adoption ratios are expected to flip over the next 3–5 years, making whether a supplier's product lineup is SiC-capable an important axis of competitive evaluation.