Comparing IGBT vs. SiC MOSFETs in High-Power Applications

A practical comparison for engineers, power-industry professionals, and decision makers.

Why Compare IGBT and SiC MOSFETs?

In the world of high-power electronics, two device families dominate most discussions: insulated gate bipolar transistors (IGBTs) and silicon carbide (SiC) MOSFETs. Both technologies are widely used in converters, inverters, and motor drives. Each has strengths and weaknesses, and the right choice depends on performance, cost, and reliability needs. For engineers and decision makers, understanding these differences helps in selecting the right path for new projects.

Understanding the Basics

IGBTs combine the easy gate drive of MOSFETs with the high-current handling of bipolar transistors. They have been the standard in many high-voltage and high-current systems for years. SiC MOSFETs, on the other hand, are built on wide-bandgap material. This gives them the ability to switch faster, operate at higher temperatures, and reduce energy loss.

On paper, SiC MOSFETs look like the natural successor. In practice, the choice is not that simple. Factors such as cost, supply chain, and long-term reliability all come into play.

Efficiency in Real Systems

Efficiency is one of the strongest selling points for SiC MOSFETs. They switch faster and waste less energy during operation. This means smaller heat sinks, lighter systems, and improved overall system efficiency. In high-frequency applications, the difference becomes even more visible.

IGBTs are efficient in certain operating ranges but tend to lose ground in fast-switching applications. They handle conduction well, but their switching losses increase with frequency. This is why IGBTs remain strong contenders in slower-switching, high-current environments.

Cost Considerations

Cost is often the first question raised in boardrooms. IGBTs are generally less expensive and benefit from decades of manufacturing maturity. Their supply chain is stable, and volumes are high, keeping unit prices lower.

SiC MOSFETs are more expensive, partly because of the complexity of producing wide-bandgap materials. However, system-level costs may tell a different story. With SiC devices, smaller cooling systems, lighter passive components, and compact designs can offset higher device prices. In some cases, the total cost of ownership favors SiC even if the devices themselves are more costly.

Reliability Factors

Reliability is a core concern for both device families. IGBTs have proven themselves over decades in industrial, automotive, and power transmission applications. Their failure modes are well understood, and engineers trust them in mission-critical systems.

SiC MOSFETs are newer and continue to prove themselves in real-world environments. They tolerate higher operating temperatures and voltage stresses, which gives them a natural advantage in harsh conditions. However, because they are newer, long-term field data is still being gathered. For applications where proven reliability is non-negotiable, IGBTs may remain the safer bet. For projects pushing efficiency and performance limits, SiC is increasingly attractive.

Thermal Performance

Thermal management is always a concern in power electronics. SiC MOSFETs operate efficiently at higher temperatures, reducing the size of cooling solutions. This simplifies packaging and lowers weight, which is especially valuable in mobile and aerospace systems.

IGBTs typically require larger heat sinks or cooling solutions to maintain safe operating limits. This adds cost and size to the system. For stationary or large-scale equipment where space is less of a concern, this may not be a major drawback. But in compact, weight-sensitive systems, the difference can be critical.

Design Complexity and Learning Curve

Designing with IGBTs is familiar territory for most engineering teams. Gate drive requirements, protection schemes, and thermal behavior are well known. Tools, reference designs, and expertise are abundant.

SiC MOSFETs require careful handling of gate drive design, switching transients, and electromagnetic interference. Engineers must adapt to faster edge rates and different packaging constraints. This learning curve can add development time, but the results often justify the effort.

Application Fit: Where Each Device Wins

In industrial drives, renewable energy converters, and traction inverters, both technologies compete. IGBTs remain strong in cost-sensitive, lower-frequency applications such as motor drives or uninterruptible power supplies. Their proven reliability and lower cost make them an easy choice.

SiC MOSFETs shine in fast-switching converters, high-density chargers, and aerospace systems where efficiency and size matter. They enable higher power density and faster response times, making them ideal for advanced energy storage systems and cutting-edge transportation technologies.

Strategic Decision Making

For decision makers, the comparison between IGBT and SiC MOSFETs should not focus only on device cost. It is about the entire system. Efficiency gains, reduced cooling, and improved performance can justify the premium of SiC. But if reliability and predictable supply are top priorities, IGBTs continue to deliver dependable results.

A balanced approach is often best. Some systems even combine both technologies in hybrid designs, using IGBTs for bulk power and SiC MOSFETs for fast-switching stages.

Choosing the Right Device

Both IGBTs and SiC MOSFETs have a place in high-power applications. The right choice depends on priorities. If cost and proven reliability dominate, IGBTs remain the technology of choice. If efficiency, size reduction, and future-ready performance are more important, SiC MOSFETs are a compelling option.

The global shift toward electrification and renewable energy will only increase demand for both technologies. Engineers who understand their trade-offs and decision makers who evaluate total system value will be best positioned to navigate this changing landscape.

Global EV Market Growth and Its Impact on Power Electronics Demand

A practical guide for electrical engineers, power-industry professionals, and decision makers.

Introduction: EV Market Growth and Power Electronics

Electric vehicles (EVs) are reshaping the automotive and power sectors. In 2025, global EV sales are projected to exceed 20 million units — a dramatic jump from only a few years earlier. For electrical engineers and decision makers, this rapid EV market growth translates directly into rising power electronics demand.

Why EV Adoption Drives Power Electronics Demand

EVs depend on power electronics at every level: traction inverters, onboard chargers, DC–DC converters, and battery-management circuits. As adoption accelerates, the market size for these components is expected to reach tens of billions of dollars. Each EV sold means additional units of high-value power electronics shipped, tested, and serviced.

Key Power Electronics Components in EVs

• Traction Inverters: Convert DC from the battery to AC for the motor, central to EV performance.
• Onboard Chargers (OBCs): Manage AC charging, now expanding to bidirectional vehicle-to-grid functions.
• DC–DC Converters: Step down high battery voltage to power auxiliaries and infotainment systems.
• High-Voltage Contactors and Power Modules: Ensure safety and reliability under demanding thermal and vibration stress.

Wide-Bandgap Devices: SiC and GaN

The EV boom has accelerated the shift from traditional silicon devices to wide-bandgap semiconductors such as silicon carbide (SiC) and gallium nitride (GaN). These materials enable:

• Higher efficiency and lower energy loss
• Smaller, lighter, and more compact designs
• Higher operating temperatures and simpler cooling

For engineers, mastering SiC and GaN design (gate drivers, EMI control, thermal management) is now a competitive advantage.

Impact on Power Grids and Infrastructure

The rise of EVs affects more than vehicles — it transforms the power grid. Key challenges include:

• Charging load: Fast-charging stations place heavy demand on local distribution networks.
• Vehicle-to-grid (V2G): Bidirectional chargers create opportunities for grid support and renewable integration.
• Power quality: Large-scale EV charging can increase harmonics, requiring advanced converters and filters.

Supply Chain and Manufacturing Considerations

With global EV market growth, supply chains are under pressure. SiC wafers, capacitors, and packaging capacity are critical bottlenecks. OEMs and suppliers need to:

1. Diversify sourcing for key semiconductors
2. Invest in high-voltage testing and assembly
3. Focus on reliability engineering to avoid costly field failures

Strategic Actions for Engineers and Decision Makers

• Upskill teams in SiC/GaN design and simulation
• Perform total cost of ownership analysis for device choices
• Coordinate early with utilities for fleet or depot charging
• Design modular and serviceable power units
• Monitor supply-chain trends and secure long-term agreements

Risks and Forecast Uncertainty

While EV adoption is growing fast, forecasts differ by region and technology readiness. Policy changes, raw material costs, and manufacturing scale for SiC and GaN will shape outcomes. Flexible strategies and scenario planning are essential.

Conclusion: A Growing Market, A Rising Challenge

The global EV market is creating one of the largest growth opportunities for power electronics. Engineers, manufacturers, and decision makers who act now — mastering wide-bandgap devices, planning for grid integration, and building resilient supply chains — will be positioned to lead.

Takeaway: Power electronics is no longer just a subsystem — it is the heart of EV performance, safety, and energy efficiency.

Understanding IEC 60909 for Short-Circuit Calculations

Short-circuit calculations are a daily requirement for electrical engineers who design, operate, or protect power systems. Knowing the prospective short-circuit currents in a network is essential for selecting breakers, relays, busbars, cables, and ensuring overall safety. The IEC 60909 standard gives engineers a common framework for calculating these short-circuit currents.

This article explains IEC 60909 in simple language, focusing on why it matters, what it covers, how to use it, and what engineers should remember in practice.

Why short-circuit calculations matter

Whenever a fault occurs — line-to-line, line-to-earth, or three-phase — the system experiences a huge surge of current. This short-circuit current:

Creates thermal stress (heating of conductors, cables, and equipment).

Produces mechanical stress (electrodynamic forces on busbars, contacts, windings).

Must be cleared safely by circuit breakers and protection relays.

Determines the required withstand ratings of all equipment.

Without reliable calculation methods, engineers risk underestimating these currents, leading to unsafe equipment operation, fires, or blackouts.

IEC 60909 provides formulas, assumptions, and a structured method to compute these currents under realistic system conditions.

What is IEC 60909?

IEC 60909 is an international standard titled: Short-circuit currents in three-phase a.c. systems.

It provides:

Rules for calculating short-circuit currents under different fault conditions.

Simplified methods for both balanced and unbalanced faults.

Guidance on modeling equipment (generators, transformers, lines, motors).

Correction factors for real-world effects (voltage tolerances, transformer impedance, etc.).

It is widely used by utilities, consultants, and industrial plant engineers as the reference method for fault current calculations.

Types of short-circuit currents in IEC 60909

The standard distinguishes between several key values:

Initial symmetrical short-circuit current (Ik" or I"k)

The RMS value at the moment the short circuit occurs (immediately after fault initiation).

Important for calculating breaker making capacity and dynamic forces.

Peak short-circuit current (Ip)

The maximum instantaneous current peak during the first half-cycle.

Critical for mechanical design (busbar bracing, switchgear withstand strength).

Steady-state short-circuit current (Ik)

The current that remains after the transient effects decay.

Used to check equipment thermal withstand and long-duration effects.

Breaking current (Ib)

The current that circuit breakers must interrupt at the moment of arc extinction.

Fault types covered

IEC 60909 covers both balanced and unbalanced faults:

Three-phase short circuit (3Φ) → usually the highest current, used for equipment dimensioning.

Two-phase short circuit (2Φ).

Two-phase to earth fault (2Φ–E).

Single-phase to earth fault (1Φ–E) → very common in distribution networks.

The standard provides symmetrical component methods to calculate the currents for these faults.

Key assumptions in IEC 60909

To keep calculations consistent, the standard makes some simplifications:

Voltage factor (c):

Faults are calculated using a factor to account for system voltage variations.

Example:

1.05 × nominal voltage for maximum short-circuit current.

0.95 × nominal voltage for minimum short-circuit current.

Equipment modeling:

Generators, transformers, lines, and motors are modeled using equivalent impedances.

Synchronous machines contribute strongly at the start but decay over time.

Induction motors contribute transient current for a short duration after fault inception.

Neglecting arc resistance:

For worst-case calculations, arc resistance is neglected (since it would reduce fault current).

How to apply IEC 60909 in practice

A practical workflow for engineers:

Gather system data

Voltage levels, transformer ratings and impedances, line lengths and impedances, generator/motor data.

Create equivalent impedances

Convert all equipment to per-unit or Ohm impedances at a common base.

Select fault location

Choose busbars or nodes where faults will be studied.

Apply IEC 60909 formulas

Compute initial symmetrical current, peak current, and steady-state current.

Check equipment ratings

Compare calculated values with breaker making/breaking capacity, busbar withstand strength, cable thermal limits, and relay settings.

Document results

Maintain clear calculation sheets or simulation reports for compliance and safety records.

IEC 60909 vs. simulation tools

Modern engineers often use software (ETAP, DIgSILENT PowerFactory, SKM, CYME) to do these calculations automatically. These tools usually implement IEC 60909 in the background.

However, understanding the theory and equations is important:

To validate software results.

To spot unrealistic inputs or outputs.

To explain results to auditors, regulators, or clients.

Example (simplified)

Let’s say you want to calculate the three-phase fault current at a 11 kV bus fed by a transformer.

Transformer: 20 MVA, 11/66 kV, 10% impedance.

Short-circuit power base = (MVA × 100) / Z% = (20 × 100) / 10 = 200 MVA.

Equivalent short-circuit current at 11 kV = (200 MVA) / (√3 × 11 kV) ≈ 10.5 kA.

From this base value:

Initial symmetrical short-circuit current Ik" ≈ 10.5 kA.

Peak current Ip ≈ k × √2 × Ik", where k ≈ 1.8 (from IEC factors). → about 26.7 kA.

This simple calculation shows how IEC 60909 guides you to realistic numbers used for breaker sizing.

Why IEC 60909 remains important

Even with advanced simulation tools, IEC 60909 provides:

Consistency → all engineers use the same base rules, ensuring comparable results.

Safety → ensures no underestimation of fault currents.

Compliance → many regulators and utilities require IEC 60909-based studies.

Reliability → helps prevent equipment failure and system blackouts.

IEC 60909 is not just a theoretical document. It is a practical tool that every electrical engineer should understand. It helps you calculate fault currents in a structured way, check equipment ratings, and design safe power systems.

If you are an engineer working in utilities, industrial plants, data centers, or renewable energy projects, mastering IEC 60909 is essential for ensuring your designs are safe, reliable, and compliant.

Electric Trucks: Driving the Future of Freight

 Electric trucks (ETs) have rapidly emerged as a transformative force in the transportation and logistics sector. As governments, businesses, and consumers seek cleaner, more efficient, and sustainable alternatives to traditional diesel trucks, the adoption of electric trucks has accelerated. 

Benefits of Electric Trucks

Environmental Advantages

One of the primary benefits of electric trucks is their ability to reduce greenhouse gas emissions and improve air quality. Diesel-powered trucks are significant contributors to carbon dioxide (CO₂), nitrogen oxides (NOₓ), and particulate matter emissions, which contribute to climate change and urban pollution. Electric trucks, powered by batteries, eliminate tailpipe emissions entirely and can significantly lower the carbon footprint, especially when charged using renewable energy sources.

Reduced Operating Costs

Electric trucks often have lower operating costs compared to their diesel counterparts. Electricity is generally cheaper per kilometer than diesel fuel, and electric drivetrains have fewer moving parts, reducing maintenance expenses. Components such as oil filters, exhaust systems, and gearboxes, which require frequent servicing in conventional trucks, are absent or simplified in electric models.

Quieter Operations

Electric trucks produce significantly less noise than diesel trucks. This makes them ideal for urban deliveries and night-time operations, where noise pollution is a concern. Reduced noise also improves the working environment for drivers and reduces disturbances in residential areas.

Performance and Efficiency

Electric trucks provide instant torque, delivering better acceleration and smoother operation compared to diesel trucks. Regenerative braking captures energy during deceleration, improving overall efficiency and reducing brake wear.

Downsides of Electric Trucks

High Upfront Costs

One of the major challenges is the high initial purchase price. Although operating costs are lower over time, the upfront investment for electric trucks is significantly higher due to expensive battery technology.

Limited Range

Current battery technology limits the driving range of electric trucks, particularly for heavy-duty long-haul transport. While light and medium-duty trucks can efficiently handle city and regional routes, long-haul operations often require frequent recharging or large battery packs, which add weight and reduce payload capacity.

Charging Infrastructure

The lack of widespread charging infrastructure is a critical bottleneck. While passenger EV charging networks have expanded, charging stations capable of supporting high-capacity trucks (including megawatt charging) are still in early stages of deployment.

Longer Downtime for Charging

Recharging an electric truck takes longer than refueling a diesel truck, particularly when using standard chargers. This can impact fleet productivity unless fast-charging or battery swapping solutions are available.

Battery Degradation and Recycling

Over time, batteries lose capacity, reducing range. Additionally, battery disposal and recycling remain environmental and logistical challenges that need more mature solutions.

Growth of Electric Trucks in the Past Few Years

Electric trucks have moved from experimental pilots to commercial adoption in recent years, driven by advancements in battery technology, government incentives, and stricter emissions regulations.

• Global Sales Growth: In 2020, electric truck sales were in the tens of thousands, dominated by China. By 2024, global sales of medium- and heavy-duty electric trucks surpassed 90,000 units, with growth of nearly 80% year-on-year, largely due to urban logistics, regional haulage, and last-mile delivery demands.

• China Leads the Market: China has been the dominant player, accounting for more than 80% of global sales, thanks to strong policy support, subsidies, and domestic manufacturing capacity.

• Europe and North America Catching Up: Europe has set aggressive carbon reduction targets for heavy-duty vehicles, pushing manufacturers and fleet operators toward zero-emission options. In the U.S., companies like Tesla, Freightliner, Volvo, and Nikola have launched or expanded electric truck models for freight and logistics.

• Diverse Segments: Light- and medium-duty trucks (delivery vans, refuse trucks, regional haulers) are leading the transition, while long-haul electric trucks are beginning to emerge with models like the Tesla Semi and Mercedes-Benz eActros 600.

Scope for Wider Adoption

Technological Advancements

The pace of innovation in battery technology (e.g., solid-state batteries, higher energy densities) is expected to improve range and reduce costs significantly over the next five years. Megawatt charging systems (MCS) are also being deployed, enabling faster recharging for long-haul trucks.

Government Policies and Incentives

Government initiatives worldwide, such as subsidies, tax incentives, zero-emission mandates, and carbon penalties, will accelerate adoption. The European Union has mandated a 90% CO₂ reduction for heavy-duty vehicles by 2040, and several U.S. states are adopting Advanced Clean Truck (ACT) rules.

Total Cost of Ownership (TCO) Parity

Analysts project that by 2027–2030, electric trucks will reach TCO parity with diesel trucks in most urban and regional duty cycles. High fuel prices, improved battery economics, and declining maintenance costs will strengthen the business case.

Integration with Renewable Energy and Smart Grids

Electric trucks can play a key role in grid balancing and vehicle-to-grid (V2G) services, especially for fleet depots with predictable schedules. Pairing with renewable energy sources enhances their environmental benefits.

Corporate Sustainability Commitments

Major logistics companies like DHL, UPS, FedEx, and Amazon are committing to electrify large portions of their fleets to meet corporate sustainability and net-zero targets.

The Road Ahead

Electric trucks are poised to transform freight transport, starting with urban and regional logistics and gradually expanding into long-haul segments as technology matures. Key enablers will include:

• Expansion of high-capacity charging networks (e.g., megawatt chargers).

• Standardization of charging protocols across regions and manufacturers.

• Continued investment in battery recycling and second-life use.

• Government policies that balance incentives with infrastructure funding.

• Integration of autonomous driving technologies, which could further enhance efficiency.

While challenges remain, the trajectory is clear: electric trucks are not a niche experiment anymore—they are becoming a mainstream solution for sustainable freight.

Understanding Harmonics

Harmonics are undesirable components in the sinusoidal waveform of the AC Power supply. Harmonics occur as integral multiples of the fundamental frequency. That is, the third order harmonic will have a frequency of 3 times the fundamental frequency; 150 Hz which is 3 times the fundamental 50 Hz frequency. Harmonics affect power quality and equipment life and efficiency.

It is therefore necessary that Harmonics in any power system be monitored. Should Harmonics be present, they can be rectified by using suitable methods such as filters.

Causes of Harmonics

Harmonics are caused by Non-Linear Loads. The majority of electrical loads are linear meaning that the current varies sinusoidally with the voltage, though it may have a phase displacement.

However, of late, the proliferation of electronic devices such as Variable frequency drives, chopper circuits, inverters, etc cause non-linear loading of the power system. The current does not vary sinusoidally with the voltage. This leads to harmonics in the power system. The fundamental frequency will have many other frequencies superimposed on itself. This causes distortion of the waveform.

Using a mathematical technique known as Fast Fourier Transforms, the distorted AC waveform can be resolved into its component waveforms. Of the measured harmonics, the even harmonics(harmonics whose frequency are the fundamental frequency multiplied by even numbers such as 100Hz(2 *50) or 200Hz(4*50) get cancelled out and have no effect. For the study and management of Harmonics, only the odd harmonics are considered.


Effects of Harmonics

Harmonics have a wide range of effects such as heating of conductors, motors etc which can affect equipment efficiency. Besides, they can cause transient over/under voltages and can cause equipment failure.

Harmonic Analysis

If the problem of Harmonics is suspected, a harmonic analysis needs to be conducted. Harmonic analyzers are dedicated equipment to study the harmonics in a power supply. Typical Analyzers can resolve harmonics upto the 25th order.

Harmonics can be neutralized by means of Harmonic filters. Harmonics filters are usually LC circuits tuned to the frequency of the particular order of harmonics to be neutralized.

Voltage Classification - LV, MV and EHV

AC voltages have been classified in various manners.  In earlier times, there were just two categories LV and HV.  As the level of voltages increases, there was a need for more levels.  However, there was ambiguity as to where each band ended and the other began.  For instance, 11kV can be MV in some systems and HV in another. 

The International Electrotechnical Commission has classified the voltages into the following levels(IEC 60038).  This classification system is fast gaining acceptance. 

Low Voltage           - upto 1000V

Medium Voltage     - 1000V to 35kV

High Voltage           - 35kV to 230 kV

Extra High Voltage  - above 230 kV.


In some situations, the term Ultra High Voltage is used to denote voltages above 800 kV.

In addition, the IEC defines a voltage band known as the Extra Low Voltage with a AC voltage less than 70 V.  See article here.

Braking methods in Induction motors

Braking in induction motors refers to quickly bringing the speed of the motor to zero.  Braking can be categorized into two broad categories viz. mechanical braking and electrical braking.
Mechanical braking involves stopping the shaft by means of a braking shoe.  When the braking is to be done, the supply to the motor is cut off and the brake is applied to bring the motor to a halt.
Mechanical braking used in cranes and hoists.  It is also used in elevators when the elevator has to stop at a specific floor of the building.

Electrical braking involves stopping the motor using electrical means.  Most electrical braking systems have a mechanical brake to hold the shaft in position once the machine has been stopped.
There are two main types of Electrical braking.

1. Plugging
2. Dynamic braking
3. Regenerative braking

Plugging
Plugging involves reversing the supply in two of the phases.  For instance, R and Y can be interchanged.  This leads to a torque being developed in the opposite direction to the rotation of the motor.  This causes the motor to stop at once.  Once the motor stops, the reverse supply is cut off (to prevent the motor from running in the opposite direction).  The rotor is secured by a mechanical brake.
Dynamic Braking can be classified into DC injection braking, AC dynamic Braking and Capacitor Braking.
AC dynamic Braking
In AC dynamic braking, the supply to one of the phases is cut off.  Thus the motor runs as a single phase motor.  This induces negative phase sequence components in the supply and the motor stops.  Another method is to give the remove one phase and give the same phase to two terminals.  For instance, two terminals will have 'Y' phase and one will have 'B' phase.
DC injection braking
In DC injection braking, a separate rectifier circuit produces a dc supply.  When the brake is to be applied, the ac supply to the stator is disconnected and a dc supply is given to two of the phases.  The dc voltage in the stator sets up its own magnetic field.  The conductors of the rotor which is rotating will cut the magnetic field.  As the conductors are short circuited, a high current is produced.  This causes a braking torque to be produced in the rotor.  The current produced in the rotor is dissipated as heat.  This system can be used only when the rotor can withstand the heat which will be produced when the brake is applied.
Capacitive Braking
Here the AC supply to the stator terminals is cut off and the terminals are connected to a three phase capacitor bank.  The capacitors will excite the induction generator.  This sets up a magnetic field which will cut the rotor bars.  The rotor energy is thus converted into heat and the motor is stopped.
Regenerative Braking
In Regenerative braking,  the supply frequency to the stator is reduced.  This is possible with VFDs where the frequency can be varied.  When the supply frequency is reduced, the synchronous speed of the motor is reduced. When the synchronous speed falls below the rotor speed, the induction motor works as an induction generator and power is supplied back to the terminals.  The energy in the rotor is thus recovered.  Due to the loss of energy, the rotor slows down and stops.