Material Insights · Understanding the Material World

Transformers and power electronics: Equipment and suppliers

Cores, windings and the chips that switch them

What this tab covers For each method, the main pieces of equipment, who makes them (by region) and what they are made of (bill of materials).

The core items are the transformer core and windings, the semiconductor power module, and the passive parts (capacitors, inductors, heatsinks) around it.

Transformers

Large power transformer313

Steps voltage between generation, transmission and distribution levels; typically 150-400 tons, so needs special rail cars.

Europe Hitachi Energy (Switzerland), Siemens Energy United States GE Vernova (Prolec GE), Delta Star Japan and Korea HD Hyundai Electric, Hyosung Heavy Industries China TBEA, China XD Electric, Baoding Tianwei Baobian India CG Power
Bill of materials
  • Windings: Continuously transposed copper conductor with paper insulation Roughly 25% of production cost
  • Core: Grain-oriented silicon electrical steel laminations (amorphous steel cuts loss further but is brittle) Roughly 25% of production cost
  • Tank, insulating oil, bushings, tap changer, cooling: Steel tank, mineral oil, porcelain or composite bushings Remainder, with labour about 36% of manufacturing cost

Inverters, drives and chargers

Power semiconductor module6

The switch at the heart of every converter; sets efficiency and size.

Europe Infineon, STMicroelectronics United States onsemi Japan and Korea Mitsubishi Electric, Fuji Electric
Bill of materials
  • Chips: Silicon IGBTs and diodes; silicon carbide MOSFETs; gallium nitride transistors Not published
  • Package: Ceramic substrate with copper layers, bond wires, baseplate Not published
Solar and battery inverter814

Converts DC from panels or batteries into grid-synchronised AC.

China Huawei, Sungrow, Ginlong Solis, GoodWe Europe SMA, Fronius United States Enphase Japan and Korea TMEIC Rest of world SolarEdge (Israel)
Bill of materials
  • Power stage: Semiconductor modules, inductors (copper and ferrite or iron powder), film capacitors Not published
  • Enclosure and cooling: Aluminium housing and heatsinks, fans Not published
  • Control and protection: Microcontroller boards, sensors, relays Not published
DC fast charger151718192021

Converts grid AC to controlled DC at the battery's voltage, at tens to hundreds of kW.

Europe ABB E-mobility, Kempower, Alpitronic United States Tesla (Supercharger) China TELD, Star Charge
Bill of materials
  • Power modules: Active rectifier with power-factor correction, then an isolated DC-DC converter, increasingly with silicon carbide switches Not published
  • Cooling, cable and connector: Liquid or forced-air cooling; liquid-cooled cables at the highest powers Not published
  • Controls and payment: Communication with the vehicle and back office, metering, payment terminal Not published

Sources

  1. Large Power Transformers and the U.S. Electric Grid US Department of Energy, Office of Electricity, 2012
  2. Infineon investor presentation Q4 FY2025 (citing Omdia, October 2025) Infineon Technologies, 2025
  3. Huawei, Sungrow lead Wood Mackenzie's inverter market ranking pv magazine USA, 2026
  4. Large Power Transformer Resilience: Report to Congress US Department of Energy, 2024
  5. Global PV inverter shipments grew by 10% in 2024 to 589 GWac (press release, 10 July 2025) Wood Mackenzie, 2025
  6. DC fast charger infrastructure testing (ABB Terra 53 efficiency) Idaho National Laboratory, 2016
  7. Kempower Annual Report 2025 Kempower, 2026
  8. Kempower Capital Markets Day 2026 presentation Kempower, 2026
  9. ABB sells majority of Chinese charging specialist Chargedot electrive, 2025
  10. About us Alpitronic, 2026
  11. Tesla Form 10-K for fiscal year 2025 Tesla / US SEC, 2026