Electric motor drive systems form the backbone of industrial automation. From pumps, compressors, and conveyors to robotics, packaging, and precision motion control, motor drives are embedded across industrial processes worldwide. Collectively, these systems account for close to half of global electricity consumption, making them a central focus for efficiency improvements, regulatory compliance, and sustainability initiatives.
As industrial applications demand higher efficiency, greater power density, and improved dynamic performance, the limitations of conventional silicon (Si) power devices are becoming increasingly apparent. Switching losses, thermal constraints, and frequency limitations restrict the ability of conventional Si-based power conversion designs to meet modern performance expectations without increasing size, complexity, or cost.
Wide bandgap (WBG) semiconductors offer a compelling alternative. The material properties of silicon carbide (SiC) and gallium nitride (GaN) enable the manufacture of devices with higher switching frequencies, lower losses, and operation at elevated temperatures. Leading semiconductor manufacturers, such as Nexperia, are enabling this transition with expanding portfolios of SiC MOSFETs and GaN FETs designed for industrial motor drive applications.
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Segmentation of Drive Applications in Industrial Automation
Industrial motor drives span a wide range of power levels, voltages, and performance requirements. Understanding this segmentation is essential when evaluating how WBG devices can deliver the greatest benefit.
High-Power, High-Voltage General-Purpose Drives
High-power drive systems typically operate above 100 kW, with DC link voltages ranging from 690 V up to several kilovolts. These drives are widely used in heavy industrial motors for pumps, compressors, fans, traction systems, mining equipment, and large HVAC installations. Key design requirements in this segment include high efficiency across wide load ranges, robust short-circuit capability, and long-term reliability in mission-critical environments.
Si IGBTs have traditionally dominated this space, often implemented in multi-level or series-connected topologies to manage voltage stress. While effective, these solutions face inherent limitations: switching losses restrict practical switching frequencies to a few kilohertz, leading to large output filters and increased current ripple. At the same time, thermal management requirements drive larger heatsinks and forced cooling, increasing cabinet size and system complexity.
In the face of increasingly stricter efficiency regulations, drive manufacturers are striving to reduce losses while maintaining or reducing system size, making power density a key differentiator. These combined pressures are driving a transition towards SiC-based solutions. SiC devices, with high voltage capability, low conduction and switching losses, and high-temperature operation, provide a practical path to improving efficiency while simultaneously increasing power density.
Servo Drive Systems
Servo drives cover a broad mid-power range, typically from 0.5 kW to 100 kW, operating at voltages between 200 V and 700 V. Applications include CNC machines, robotics, packaging equipment, and advanced automation systems.
Unlike general-purpose drives, servo systems prioritise dynamic performance rather than raw power capability. High current control bandwidth, fast torque response, and precise position control are essential, and switching frequency has a direct impact on achievable performance.
As performance requirements continue to rise, conventional Si devices increasingly limit the capabilities of servo drives. Higher switching frequencies improve current control bandwidth and torque smoothness, but in Si-based designs, they quickly lead to rising switching losses and thermal stress. This has driven the growing adoption of WBG devices. With significantly lower switching losses and faster switching characteristics, SiC and GaN devices enable higher Pulse Width Modulation (PWM) frequencies while maintaining high efficiency, resulting in improved dynamic response and motion quality without excessive thermal complexity.
In high-performance servo drives, this capability enables PWM switching frequencies to extend well beyond 20 kHz and, in some designs, toward 50–100 kHz. Operating in this range allows current control loop bandwidths to exceed 5 kHz, supporting torque response times below 100 microseconds. These improvements directly benefit field-oriented control (FOC) performance by reducing current ripple, improving phase alignment, and enhancing disturbance rejection during rapid load or speed changes.
Low-Voltage Drive Systems
Low-voltage drives typically operate below 10 kW with DC voltages at or below 100 V. Applications include appliance motors, power tools, small industrial automation, and battery-powered e-mobility platforms such as e-bikes, scooters, and light electric vehicles.
This segment is highly cost-sensitive and has traditionally relied on Si MOSFETs; rising demands for efficiency, battery life, acoustic performance, and control quality, however, are now stretching the practical limits of these Si-based solutions. GaN devices are therefore gaining traction in this segment.
GaN FETs combine fast switching speeds, low gate charge, and near-zero reverse recovery losses, enabling much higher switching frequencies with excellent efficiency. These characteristics make GaN particularly well suited to low-voltage motor drives where power density, smooth torque production, and precise control are critical.
Silicon Carbide Advantages in Drive Applications
SiC has emerged as a key enabling technology for medium- and high-voltage motor drives. Its WBG, high critical electric field strength, and excellent thermal conductivity allow SiC devices to outperform Si across multiple dimensions.
SiC MOSFETs can block higher voltages in thinner drift regions, switch faster with significantly lower losses, and operate reliably at junction temperatures up to 175 °C. These characteristics enable meaningful improvements at the system level, particularly in high-power industrial drives.
| Parameter | Silicon Carbide (SiC) | Silicon (Si) |
|---|---|---|
| Band gap energy | 3.26 eV | 1.12 eV |
| Critical electric field | ~10× higher than silicon | Baseline |
| Thermal conductivity | ~3× higher than silicon | Baseline |
| Electron saturation velocity | ~2× higher than silicon | Baseline |
| Maximum junction temperature | Up to 175 °C | Typically up to 150 °C |
Reduced Switching Losses and Higher Efficiency
SiC MOSFETs switching losses are typically 50-80 % lower than equivalent Si IGBTs. In high-power drives, this reduction translates into efficiency improvements of one to two percentage points, which become highly significant over continuous operation.
Industrial-grade SiC MOSFETs, including those offered by Nexperia in 650 V and 1200 V classes, enable designers to achieve these gains while maintaining ruggedness and long-term reliability. Lower losses also reduce heat generation within the inverter, easing thermal management requirements and improving system lifetime.
In a typical 250 kW drive operating at 10 kHz switching frequency, the reduced losses translate to:
- Reduction in semiconductor losses from ~2 % to <1 % of rated power
- Efficiency improvements of 1-2 percentage points
- Energy savings of 2,500-5,000 kWh annually per drive
- Reduced cooling system requirements
Higher Switching Frequencies and Improved Control
The low switching losses of SiC devices allow high-power drives to operate at switching frequencies of 20-50 kHz, compared to the 2-8 kHz range typical of Si IGBT solutions. This enables substantial reductions in output filter size, often cutting inductor volume by 40-60 %. Higher switching frequencies also reduce motor current ripple, lowering torque ripple and acoustic noise.
In servo drive applications, this translates directly into faster torque response and improved disturbance rejection, with current control loop bandwidths extending into the several kilohertz range and torque response times typically below 100 microseconds in high-performance systems.
Simplified Thermal Management and System Design
SiC’s ability to operate at higher junction temperatures, combined with reduced total losses, enables smaller heatsinks and, in some cases, the elimination of forced-air cooling. In numerous instances, heatsink volume reductions of 30-50 % are achievable, supporting higher power density and more compact drive designs.
In medium- and high-voltage converters, SiC devices also enable system-level simplification; for example, their higher voltage capability and improved switching performance allow designers to move from multi-level to simpler two-level topologies, reducing component count and improving reliability. These system-level benefits often offset the higher component cost of SiC devices.
Gallium Nitride Advantages in Low-Voltage Drives
GaN, typically implemented as high-electron-mobility transistors (HEMTs), combines a WBG with extremely high electron mobility, very low gate charge, and near-zero reverse recovery losses, offering the following advantages to motor drive designers.
GaN, particularly in HEMT form, offers distinct advantages for low-voltage applications:
- Band gap energy: 3.4 eV
- Critical electric field: Similar to SiC, ~10× silicon
- Electron mobility: 5× higher than silicon
- Very low gate charge and output capacitance
- Near-zero reverse recovery charge
- Lateral device structure enabling monolithic integration
Ultra-Fast Switching and Compact Designs
GaN FETs switch extremely fast, with transition times in the nanosecond range, enabling PWM switching frequencies that routinely exceed 100 kHz and, in suitable low-voltage designs, extend into the several hundred kilohertz range. Unlike conventional Si devices, GaN maintains high efficiency under hard-switching conditions at these elevated frequencies, with switching losses showing minimal variation across the operating temperatures.
GaN devices from Nexperia, such as the GAN041-650WSB from their 650 V GaN FET portfolio, are therefore well suited to low-voltage motor drives, Figure 1, where higher switching frequencies improve current control, reduce ripple, and enhance waveform quality in BLDC and PMSM applications.
High switching frequency directly impacts passive component requirements. Inductors and output filters can be reduced by up to 70-80 % in volume, while DC-link capacitor size can also be significantly lowered. The result is a substantial increase in power density, which is particularly valuable in compact and battery-powered systems. Together, low switching losses and reduced conduction losses help limit heat generation, supporting reliable operation at elevated power density with thermal performance comparable to, or better than, Si solutions.
Figure 1: GaN devices from Nexperia’s 650 V GaN FET portfolio are well-suited to low-voltage motor drivesLow ON-Resistance
In addition to fast switching performance, GaN devices offer very low specific on-resistance, helping to minimise conduction losses even at higher current levels. For low-voltage applications, 100 V GaN devices can achieve on-resistance values below 10 milliohms in compact packages. At higher voltage ratings, such as 650 V, GaN devices typically exhibit on-resistance in the range of 20 to 50 milliohms, comparable to Si MOSFETs rated for significantly lower voltages.
This combination of low conduction loss and high switching capability supports efficient operation across a wide load range while enabling higher current density. As a result, GaN-based motor drive designs can achieve substantial improvements in power density, up to 3-5×, without incurring excessive thermal penalties.
Improved Dead Time Control and Waveform Quality
GaN devices switch extremely quickly and, as majority-carrier devices, do not suffer from reverse recovery losses that are inherent to Si MOSFETs and IGBTs. This allows motor drive designers to reduce dead time safely to the order of tens of nanoseconds, typically around 10 to 20 nanoseconds, without increasing the risk of shoot-through.
Shorter dead time reduces unwanted current flow during switching transitions, improving phase current waveform integrity and reducing harmonic distortion. The absence of reverse recovery current also lowers voltage overshoot, electromagnetic interference, and torque ripple. These timing advantages are particularly valuable in field-oriented and sensorless motor control schemes, where precise current regulation directly influences torque smoothness and low-speed performance.
Conclusion: Advancing Motor Drive Design with Wide Bandgap Technologies
WBG semiconductors represent a fundamental advancement in power electronics for industrial motor drives. SiC has established clear advantages in medium- and high-voltage applications, delivering higher efficiency, increased power density, and opportunities for system simplification, and the technology is sufficiently mature for widespread industrial deployment.
GaN, on the other hand, is emerging as the optimal solution for low-voltage motor drives, where its fast-switching capability, compact passive components, and excellent control performance unlock new levels of efficiency and integration.
SiC and GaN are complementary technologies, selected according to the specific voltage, power, and performance requirements of the motor drive. With their SiC and GaN product families addressing high, medium, and low-voltage applications, Nexperia enables designers to optimise drive solutions across the full industrial spectrum.
As a key distributor of Nexperia power semiconductor solutions, Avnet Silica supports engineers with access to qualified devices, along with technical expertise, reference designs, and supply-chain continuity to accelerate the adoption of WBG technologies in industrial automation.
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