What is the difference between IGBT and SiC inverters?

IGBT inverters use standard Silicon semiconductors and are the current industry standard. SiC (Silicon Carbide) inverters use a new wide-bandgap material that allows for faster switching, higher temperatures, and significantly reduced energy losses compared to IGBTs.

Why are SiC inverters better for trains?

SiC inverters are better because they are up to 30% smaller and lighter, reduce energy consumption by minimizing switching losses, and operate silently by pushing switching frequencies above the range of human hearing.

Is SiC more expensive than IGBT?

Yes, the initial cost of SiC modules is higher than Silicon IGBTs. However, the total lifecycle cost is often lower due to energy savings, reduced maintenance of cooling systems, and smaller physical infrastructure requirements.

The Semiconductor Revolution: IGBT vs. SiC Traction Inverters

Revolutionize railway efficiency. Compare the industry-standard IGBT with the game-changing Silicon Carbide (SiC) technology for lighter, quieter, and greener trains.

December 10, 2025 11:35 am

The Traction Inverter is the heart of a modern electric train, responsible for converting DC power (from the catenary or rectified AC) into variable frequency AC power to drive the motors. For decades, this process relied on IGBT (Insulated-Gate Bipolar Transistor) technology. However, a new challenger, SiC (Silicon Carbide), is rapidly reshaping the industry by offering superior efficiency and performance.

The Standard: IGBT (Silicon)

Since the 1990s, the Silicon-based IGBT has been the gold standard for high-voltage railway propulsion. It replaced the bulky GTO (Gate Turn-Off) thyristors, offering better control and reliability. While IGBTs are robust and cost-effective, they have physical limits regarding switching speed and thermal endurance. Much of the energy in an IGBT inverter is lost as heat during the switching process, requiring heavy cooling systems (fans, pumps, and radiators).

The Future: SiC (Silicon Carbide)

Silicon Carbide (SiC) is a “Wide Bandgap” semiconductor material. Unlike standard silicon, SiC can withstand higher voltages and temperatures while switching on and off much faster with significantly lower energy loss. This allows for inverters that are not only more efficient but also drastically smaller and lighter.

Comparison: IGBT vs. SiC Technology

The transition from Silicon to Silicon Carbide is akin to the upgrade from HDD to SSD in computing: faster, lighter, and more efficient.

Feature	Standard IGBT (Silicon)	SiC MOSFET (Silicon Carbide)
Switching Losses	Moderate (Generates Heat)	Very Low (Approx. 50-70% less)
Size & Weight	Heavy, Large Footprint	Compact (-30% volume), Lightweight
Cooling Requirements	Complex (Often Liquid Cooled)	Simple (Often Natural Air Cooled)
Audible Noise	Distinct “Whining” Sound	Silent (Ultrasonic switching frequency)
Cost	Lower Initial Cost	Higher Initial Cost (Lower Lifecycle Cost)

Why SiC Matters for Passengers and Operators

The adoption of SiC brings tangible benefits beyond just engineering stats:

Silence: SiC inverters switch at frequencies above the human hearing range (e.g., >20kHz), eliminating the characteristic “whining” noise of accelerating subway trains.
Space: Smaller inverters free up space for more passenger seats or luggage.
Energy Savings: Reduced losses mean less electricity is wasted as heat, and more braking energy is recovered, lowering the railway’s total carbon footprint.