The electric vehicle revolution is accelerating worldwide, and at its core lies a critical question: how do we charge these vehicles faster, more efficiently, and more affordably? At EVSELab, we believe the answer lies in Silicon Carbide (SiC) semiconductor technology — a wide bandgap material that is fundamentally reshaping the landscape of power electronics.
What Is Silicon Carbide (SiC)?
Silicon Carbide is a compound semiconductor material composed of silicon and carbon atoms arranged in a crystalline structure. Unlike traditional silicon (Si), SiC belongs to the family of wide bandgap (WBG) semiconductors, meaning it requires significantly more energy for electrons to jump from the valence band to the conduction band.
Key Material Properties
- Bandgap energy: 3.26 eV (compared to 1.12 eV for Si)
- Breakdown electric field: ~3 MV/cm (roughly 10x higher than Si)
- Thermal conductivity: ~4.9 W/cm-K (approximately 3x higher than Si)
- Electron saturation velocity: ~2.7 x 10^7 cm/s (2x higher than Si)
These intrinsic material advantages translate directly into real-world performance improvements in power electronic converters used for EV charging.
Why SiC Matters for EV Chargers
Higher Efficiency at the System Level
Traditional silicon-based IGBTs and MOSFETs in DC fast chargers typically achieve power conversion efficiencies in the range of 93–95%. By replacing these with SiC MOSFETs, system-level efficiencies of 97–98% become achievable. This 2–4 percentage point improvement may seem small, but at power levels of 60 kW to 360 kW, the energy savings are substantial.
For a 120 kW DC fast charger operating 12 hours per day, a 3% efficiency improvement saves approximately 1,300 kWh per year — equivalent to the annual energy consumption of a small household.
Superior Thermal Performance
SiC devices can operate at junction temperatures exceeding 175 degrees C, compared to the typical 150 degrees C limit for silicon IGBTs. More importantly, the lower conduction and switching losses in SiC devices generate significantly less heat in the first place.
This has two practical implications for charger design:
- Reduced cooling requirements: Smaller heatsinks, fewer fans, or simplified liquid cooling loops
- Higher power density: More power output from the same enclosure volume
Faster Switching Frequencies
SiC MOSFETs can switch at frequencies of 50–200 kHz in hard-switched topologies, compared to the typical 20–40 kHz range for silicon IGBTs. Higher switching frequencies enable:
- Smaller magnetic components (inductors and transformers)
- Improved output filtering with reduced ripple
- Better dynamic response to load transients
Reduced System Size and Weight
The combination of higher efficiency, better thermal characteristics, and faster switching frequencies results in charger systems that are 30–50% smaller and lighter than equivalent silicon-based designs. This is particularly important for wall-mounted AC chargers and compact DC fast chargers deployed in space-constrained urban environments.
SiC in Different Charger Topologies
AC Chargers (Level 1 and Level 2)
For AC chargers operating at 3.3 kW to 22 kW, SiC diodes in the Power Factor Correction (PFC) stage and SiC MOSFETs in the DC/DC conversion stage deliver measurable efficiency gains. The totem-pole bridgeless PFC topology, which is only practical with SiC or GaN devices, eliminates the need for a diode bridge rectifier and can achieve PFC efficiencies above 99%.
DC Fast Chargers (Level 3)
DC fast chargers operating at 30 kW to 360 kW benefit enormously from SiC technology. Common architectures include:
- Vienna rectifier front-end with SiC diodes
- Three-phase active front-end (AFE) with SiC MOSFETs for bidirectional power flow
- Phase-shifted full-bridge or LLC resonant DC/DC converters with SiC MOSFETs
At these power levels, the thermal and efficiency advantages of SiC compounds, making it the clear choice for next-generation charger platforms.
On-Board Chargers (OBC)
Vehicle-integrated on-board chargers, typically rated at 3.3 kW to 22 kW, face extreme constraints on size and weight. SiC enables OBC designs with power densities exceeding 4 kW/L, a significant improvement over the 1.5–2.5 kW/L typical of silicon-based designs.
Market Trends and Cost Trajectory
The primary barrier to SiC adoption has historically been cost. SiC wafers are more expensive to produce than silicon wafers, and manufacturing yields have traditionally been lower. However, the landscape is changing rapidly:
- 6-inch to 8-inch wafer transition: Major suppliers including Wolfspeed, STMicroelectronics, and Infineon are ramping 8-inch SiC wafer production, which will reduce per-die costs by an estimated 30–40%.
- Increased competition: Chinese SiC manufacturers such as SICC and TankeBlue are expanding capacity, adding competitive pressure on pricing.
- Volume scaling: As EV production scales globally, the demand for SiC devices is driving economies of scale.
Industry analysts project that SiC MOSFET prices will decrease by 40–50% between 2024 and 2028, making them cost-competitive with silicon IGBTs on a system-level basis when accounting for reduced cooling and passive component costs.
How EVSELab Leverages SiC Technology
At EVSELab, we have been designing SiC-based power converters since our founding. Our engineering team in Ho Chi Minh City brings deep expertise in wide bandgap semiconductor applications to every product we develop.
Our SiC Charger Portfolio
- Ladybug Platform (3.3 kW OBC): A compact on-board charger module utilizing SiC MOSFETs in a totem-pole PFC + LLC resonant topology, achieving 96.5% peak efficiency
- Grasshopper Platform (20 kW DC module): A scalable DC fast charger power module with full SiC implementation, designed for modular charger architectures
- Custom Design Services: We work with OEMs and charge point operators to develop SiC-based charger solutions tailored to specific requirements
Design Methodology
Our approach to SiC charger design follows the APQP (Advanced Product Quality Planning) framework, ensuring that every design decision — from semiconductor selection to thermal management to EMC compliance — is validated through rigorous testing at each development phase.
Looking Ahead
The convergence of falling SiC costs, increasing EV adoption, and tightening efficiency regulations is creating a perfect environment for SiC technology to become the default choice for EV charger power stages. At EVSELab, we are committed to staying at the forefront of this transition, delivering SiC-based charging solutions that are more efficient, more compact, and more reliable than ever before.
The future of EV charging is wide bandgap, and that future is already here.
Interested in learning more about our SiC-based charger designs? Contact our engineering team to discuss your project requirements.
