Motors are widely used across various applications, including small household appliances, industrial manufacturing, and heavy-duty applications. Their versatility makes them applicable for nearly any purpose. However, as motors account for approximately half of the world’s electricity consumption—a trend that continues to rise—the need to reduce carbon emissions is increasingly pressing. Therefore, improving efficiency through innovative control algorithms, adopting new, more efficient motor architectures, and leveraging modern semiconductor technology has become more critical than ever. This article will introduce the applications and market for motors, as well as related solutions provided by onsemi.
Variable frequency drives offer higher motor drive efficiency
The application range of motors spans from small-scale uses to heavy-duty applications, particularly in industrial contexts. Industrial motor drives are essential pillars of today’s global industry, with motors consuming nearly two-thirds of the energy used in all industrial applications. Industrial drives can be applied across numerous sectors, including process automation, fan control, liquid and gas pumps, robotics, material handling, machine tools, and the oil and gas industry. As regulations become increasingly stringent, the need for significant energy savings in industrial drives has become more critical. Although AC motors can typically be directly powered by an AC power source, implementing variable frequency drives (VFDs) is essential for enhanced efficiency and superior control.
Industrial drive systems utilizing VFDs are more efficient than those using conventional throttle control systems. Furthermore, other components and technologies are required in the subsystems, including gate drivers, operational amplifiers, position sensors, temperature sensors, and other control and sensing components. Modern semiconductors and innovative motor architectures are used to improve motor drive efficiency and extend the service life of motors.
The three most popular types of motors on the market today are AC induction motors (ACIM), permanent magnet synchronous motors (PMSM), and brushless DC (BLDC) motors. Additionally, stepper motors and servo systems can be used for precise positioning and controlled movement, making them widely applicable in applications requiring the holding and positioning. These motors are commonly used to power robotic arms, assembly lines, lift-assist devices, and similar applications, with high precision and high repeatability being key features of these control systems.
High-efficiency single-phase and three-phase AC motor solutions
Using onsemi's recommended single-phase and three-phase AC motor solutions as an example, the overall architecture of the motor drive structure in grid-powered motor control circuits consists of a rectifier, power supply, sensing, control hardware, and a power stage. The rectifier stage converts AC (alternating current) to DC (direct current), which can be achieved with a simple diode bridge. However, to improve system efficiency and power factor (thus reducing reactive power), a power factor correction stage can be used. An optional DC-DC stage is used to convert the DC voltage to the voltage required by the motor. Auxiliary power supply converts the AC input or DC bus to various low voltages to supply the control hardware (MCU, memory, interface, etc.) as well as gate drivers.
The brake circuit dissipates energy during deceleration, where the motor begins acting as a generator when disconnected from the power supply. Dynamic braking consumes the motor's power using a braking resistor in series with a power switch, typically an IGBT. The inverter consists of power switches that transmit power to the motor. Depending on the power level, these can be Si MOSFETs, IGBTs, or silicon carbide (SiC) MOSFETs, and may come as discrete components, power modules, or modules with integrated gate drivers.
To achieve accurate electronic commutation, it is necessary to ascertain the rotor's position. Traditionally, this is done using Hall sensors. Newer solutions use optical or inductive sensors, while some skip sensors altogether and measure back electromotive force (EMF). When precise rotor positioning is needed, inductive position sensors like the NCS32100 are especially useful during startup. The position may change while the motor is stationary, so the system cannot rely on the last known state.
onsemi's NCS32100 inductive sensor can be used to calculate position and velocity. It uses an absolute encoder to determine its position without needing to move, supporting full accuracy up to 6,000 RPM (and a maximum of 45,000 RPM) with a higher precision of ±50 arc-seconds (0.0138 degrees) on a 38 mm sensor. It can also differentiate and reject the vibrations caused by rotational movement. With an integrated Cortex-M0+ MCU and high configurability, it offers a more affordable alternative for various optical encoders.
Comprehensive product line for improved power conversion efficiency
The Power Factor Correction (PFC) stage is an AC/DC converter designed to match the input current with the shape of the input voltage, reducing harmonics and improving efficiency. onsemi’s power factor controller, the NCP1681, is a bridgeless Totem multi-mode PFC controller with features like constant on-time CrM and fixed-frequency CCM (Constant Conduction Mode) with valley switching frequency foldback, proprietary current sense scheme, and valley sense scheme technologies. This makes it an ideal choice for high-power applications, supporting up to 1 kW for multi-mode applications and over 2.5 kW in CCM. It comes in a compact SOIC-20 package.
onsemi also provides a range of inverter switches and solutions for motor control systems. These systems can be designed using discrete components (IGBTs, Si MOSFETs, SiC MOSFETs, diodes, gate drivers) or power modules that integrate multiple parts. These modules can incorporate three-phase half-bridges, one half-bridges, or even include a brake function, PFC, or gate driver in one package. Power modules are classified as Power Integrated Modules (PIM) and Intelligent Power Modules (IPM). Compared to discrete solutions, modules offer multiple benefits, as they integrate power components and protective features (like UVLO, short-circuit protection, thermal sensing) to save space and increase reliability through rigorous testing.
IGBTs are optimal for high-voltage applications because they offer higher blocking voltage than Si MOSFETs with similar material thickness. onsemi’s latest 1200 V Trench Field Stop VII IGBT series is tailored for motor control applications, with low VCE(SAT) type for enhanced power handling and reduced thermal power losses, which aids in cooling. These IGBTs feature low parasitic capacitance for improved high-frequency operation. The 1200V Gen7 diodes deliver low VF and softness recovery, minimizing noise and EMI issues.
One example, the FGY100T120RWD IGBT from the FS7 series, is a 1200V, 100A IGBT integrated with a Gen7 diode, VCE(SAT) = 1.4V, and Tjmax= 175°C, designed with a positive temperature coefficient for easy parallel operation, low conduction loss, and optimized switching for motor control applications.
SiC MOSFETs, on the other hand, provide optimal performance for high-voltage and high-frequency applications, with high electron mobility, low intrinsic carrier concentration, and high thermal conductivity. onsemi’s EliteSiC MOSFETs range from 650V to 1700V, with a unique planar design that eliminates RDS(ON), VTH, or diode-forward voltage drift over the device's lifetime.
The SiC MOSFET NTH4L014N120M3P from the 1200V M3P EliteSiC series, with ID = 152 A in a TO-247-4L package, features low switching losses, a typical EON of 1308 µJ (at 74 A, 800 V), RDS(ON) of 14 mΩ at VGS = 18 V, and an ultra-low total gate charge (QG(TOT) ) of 137 nC, making it suitable for high-speed switching with low capacitance (COSS = 146 pF).
Another EliteSiC MOSFET, the NTH4L023N065M3S from the new 650V M3S family, is designed to improve switching losses and optimize performance for high-temperature operations. It features an RDS(ON) of 22.6 mΩ at VGS = 18 V, ultra-low total gate charge (QG(TOT) ) of 87 nC, and high-speed switching with low capacitance (COSS = 153 pF), housed in a TO-247-4L package.
Highly integrated intelligent power modules and power integrated modules
Intelligent Power Modules (IPMs) represent some of the highest degree of integration among power switches, typically utilizing IGBTs or Si MOSFETs. They are particularly popular for motor control applications due to their ability to contain an entire inverter and PFC stage within a single package. Other benefits include improved EMI improvements, optimized space usage, and simplified thermal management.
onsemi’s NFCS1060L3TT is an IPM that fully integrates both PFC and inverter stages into one package. This module includes a PFC SJ MOSFET, six IGBTs, and provides 600V and 10A of current. It features built-in overcurrent and cross-conduction protection, a bootstrap diode, and NTC (Negative Temperature Coefficient) thermistor, which helps reduce PFC inductor size, simplifies heat sink design, and lowers electromagnetic interference.
Another IPM, the NFAM3065L4B, is designed for high-performance output stages of ACIM, BLDC, and PMSM. This module integrates both high-side and low-side gate drivers and six IGBTs, supporting 650V and 30A. It also has built-in overcurrent and low voltage protection, thermal monitoring, and a temperature sensor, contributing to reduced EMI and power losses.
onsemi also offers Power Integrated Modules (PIMs) utilizing both SiC MOSFET and IGBT technologies. These modules improve design efficiency and are suitable for operation at up to 1200V. IGBT devices remain popular for high-voltage, high-current applications due to their cost-effectiveness, while SiC devices offer high performance and power density, which are increasingly being adopted. PIMs may contain half-bridge, full-bridge, or even an entire three-phase inverter in one package, reducing design time, cooling requirements, and overall integration.
The NXH800H120L7QDSG is a 1200V, 800A IGBT half-bridge PIM, featuring the latest Field Stop Trench 7 IGBT technology and Gen. 7 diodes. It provides lower conduction and switching losses, enabling designers to achieve high efficiency and outstanding reliability. This module includes an NTC thermistor and low-inductance layout.
Another example is the NXH006P120M3F2PTHG, a 1200V SiC half-bridge module that utilizes M3 EliteSiC technology, with a typical RDS(ON) of 6 mΩ at VGS=18V and ID=100A. It includes a thermistor and is housed in an F2 package with HPD direct-bond copper substrate.
onsemi also offers the Elite Power Simulator, supported by PLECS®, a system-level simulator optimized for device modeling and complete system simulations, providing maximum speed and accuracy. Additionally, onsemi provides a self-service PLECS model generator, allowing users to create custom models for use in the Elite Power Simulator. PLECS offers a variety of inverter topologies suitable for industrial motor control, including half-bridge, full-bridge, and three-phase inverters.
On the other hand, MOSFETs and IGBTs must be driven by gate drivers, as MCUs or controllers cannot drive them directly. A gate driver can be a single half-bridge driver that controls one high-side and one low-side switch, or it can contain three half-bridge drivers to control all three phases of a motor. Many of the gate drivers in onsemi's product lineup support external negative bias, using external circuitry to provide negative bias for the gate driver. The new NCP51752 series features an internal negative bias, which reduces system costs by eliminating the need for an external negative bias rail. onsemi has also introduced a range of EliteSiC MOSFETs and corresponding isolated gate drivers, catering to various customer requirements for high efficiency and high performance.
Conclusion
With the increasing global demand for energy conservation and carbon reduction, new efficient motor architectures and solutions have become a key part of the energy transition. These technologies not only improve energy usage efficiency and reduce operational costs but also minimize environmental impact. Moreover, through intelligent control, advanced materials, and innovative designs, these motors achieve more flexible operation and more stable performance. onsemi can provide complete motor drive and control solutions, making it your best partner for developing related applications.