How Freezing Temperatures Impact Power Semiconductors—and Why Winter Reliability Matters More Than You Think

Across North America, winter places enormous stress on industrial systems that depend on power semiconductors. Equipment in wind farms, pumping stations, rooftop HVAC units, and outdoor drives can experience long periods sitting in sub-zero temperatures before being asked to power up under load. It’s during these cold starts and rapid warm-up cycles that IGBTs, thyristors, and power diodes encounter conditions very different from what most engineers consider during design.

Industry data shows that nearly 20% of power-electronic field failures are linked to thermal cycling, and winter environments intensify this stress more than any other season. Another study from the ECPE (European Center for Power Electronics) found that solder fatigue and bond-wire degradation account for over 55% of module reliability issues, much of it tied to repeated cold-to-hot transitions. These statistics reinforce a key point: the real challenge in winter isn’t the cold temperature itself—it’s the mechanical and electrical stress created when electronics are suddenly energized after being frozen.

Even though semiconductors tend to operate more efficiently at lower junction temperatures, deep cold introduces electrical shifts that matter during startup. For example:

• IGBTs see lower conduction losses but require higher gate threshold voltage.

• Power diodes and rectifiers exhibit higher forward voltage, increasing initial inrush.

• Thyristors (SCRs) need higher gate trigger current for reliable firing.

These shifts are predictable but become critical when a system has been dormant in freezing weather. The device characteristics themselves rarely cause failure, but they amplify stress during cold-start events.

Where the risks truly compound is in the physical structure of the modules. Power semiconductors are built from multiple layers—silicon, solder, ceramic substrates, bond wires, baseplates, and encapsulants—each with a different thermal expansion rate. When a module has been sitting at –20°C or –30°C and then experiences a rapid rise in temperature as current begins flowing, internal stresses can increase sharply. This can lead to:

• Microcracks in solder joints
• Bond-wire lift-off
• Substrate fatigue and delamination
• Premature rise in thermal resistance

Studies show that thermal-mechanical stress contributes to more than 60% of end-of-life failures in power modules, and cold-weather cycling is one of the dominant sources of that stress.

Moisture adds another winter challenge. A cold power module inside a partially sealed cabinet can accumulate condensation the moment it warms up. That moisture can cause corrosion, tracking paths, or partial discharge. The surrounding electronics—gate drivers, capacitors, sensors—may also be more temperature-sensitive than the power devices themselves. In many cases, the system fails not because the IGBT or diode wasn’t rated for low temperature, but because supporting components or the enclosure environment weren’t prepared for it.

Fortunately, winter reliability can be dramatically improved with a few practical measures. Engineers often turn to:

• Soft-start techniques to limit initial thermal and electrical shock
• Cabinet insulation or panel heaters to prevent deep cold-soaking
• Startup delay logic until the module reaches a safe temperature
• Low-temperature-rated materials and conformal coatings to prevent moisture-related damage

These strategies extend module life and reduce service calls in the coldest months of the year.

The broader market is also recognizing the importance of winter-ready components. Demand for cold-climate-rated power electronics has been increasing, with recent reports showing 7–9% annual growth driven largely by renewable energy installations, electric transportation infrastructure, and remote industrial systems. As more industries push into northern climates and outdoor environments, the issue of cold-weather reliability is gaining prominence.

At ATI, we see these challenges firsthand. Our customers—from wind farms to industrial OEMs to maintenance teams—depend on reliable, application-ready components that won’t leave them troubleshooting failures in January. That’s why we stock a wide range of IGBTs, diodes, thyristors, and rectifier assemblies from trusted manufacturers, all backed by technical guidance grounded in real-world operating conditions. If your equipment must perform reliably through winter’s coldest days, choosing the right components is a crucial first step.

To learn more about winter-ready power semiconductors—or to request components capable of withstanding extreme cold—visit www.igbts.us or connect with the ATI team: websales@igbt.us.com | 239-734-7566