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The Evolution of Electric Motor Technology

by  Nick Goodnight, PhD     Feb 27, 2026
Electric Motor Technology

As the automotive world continues to transition to a version of an electric propulsion, electric drive unit (EDU) or motor generator unit (MGU) operation must increase its efficiency to keep up with the demand of the consumer. The electric motor present in the vehicle does more than just propels the vehicle. From providing power generation in deceleration mode or converting ICE mechanical power to electrical power, the motor generator unit/electric drive unit is a vital component to the transition of the industry towards sustainable propulsion. The efficient conversion of electrical potential into physical motion has been something the industry has been working on for decades. The development of automotive grade highly efficient motors is an area that is constantly being explored to increase conversion efficiency. This report will go over a couple of different configurations that are present in new vehicles and explains how they operate, while this is not an exhaustive list, these are the currently top of the line designs.  

Electric Motor Types

Axial Flux Motors

Axial flux drive motors (AFD) have a standard set gap between the stator and rotor which provides high torque at lower RPMs and decreased torque as speed increases (Yazdi et al., 2020). The gap is the amount of space between the rotor and the stator where the flux field intersects with the opposing fields to generate motion. Standard electric machines have larger rotors and stators to convert the electricity using a radial flux into mechanical motion. Axial motors have it packaged in a better way. These machines have permanent magnets situated in such a way as the flux runs parallel with the mechanical shaft in the motor which is part of the reason for their operation in a compacted state. In some applications a dual rotor machine with each rotor opposite each other allows for current coming into one rotor, travel to the opposing rotor and then back to the power supply (Yazdi et al., 2020). This setup allows for a very compact motor with a high torque output which permits the motor to be designed into a compact drivetrain efficiently.

Variable Flux Drive Motors

Variable flux drive motors (VFD) can adjust the power of the inductance based on how close the rotor to stator air gap becomes is directly related to the efficiency of the motor. In permanent magnet applications the inherent flux of the magnetic material provides for a strong low RPM operation that is highly efficient. As the rotor speeds increase the ability of the magnetic forces dwindle thus causing top end speed variations. The use of an AC VFD motor allows for adjustment of the field strength based on the speed/load of the motor. As the gap gets larger the efficiency of the motor increases on the high-speed operation and the alternate is true as the gap needs to be smaller to increase efficiency of the motor on low-speed operation (Arribas et al., 2024). Utilizing this technology to adjust the output of the motor depending on how exciting it allows the designers to create a compact motor that meets the varying needs of an automotive application going through the various operational speeds and demands (Tsunata et al., 2019). 

Ferrari’s first electric vehicle utilizes a quad-motor powertrain where the motors achieve staggering rotational speeds. Boasting a 210kW front axle motor with a 93% efficiency, the Elettrica has the ability to operate at performance level specifications on one single axle (Ferrari, 2026). The front and rear axles can be completely disconnected from each other which allows for higher efficiency and the ability to fit the needs of the situation and allows the driver to maintain total control. The front axle motor spins up to 30,000 rpm to produce 105 kW, while the rear motor reaches 25,500 rpm (Ferrari, 2026). Integrating the power electronics with each axle drive unit allows for a more compact package and less wiring needs. To minimize the size of these power electronics, the use of Silicon Carbide (SiC) provides for increased control and operational efficiency. To combat these high RPMs Ferrari employs a Halbach Array rotor configuration which uses segmented, surface mounted permanent magnets to boost torque density while keeping the assemblies’ weight lower than that of a conventionally designed motor. To sustain these speeds, Ferrari employs a Halbach array rotor configuration using segmented, surface-mounted permanent magnets to boost torque density while reducing weight. Furthermore, they utilize Litz wire windings in the stator to mitigate "skin and proximity effects," which typically cause energy loss at such high frequencies. Litz wiring uses individually wrapped conductors that are braided in a particular pattern to equalize current distribution throughout the circuit (Rubadue Wire, 2025). Making every component of the motor highly efficient allows more power to be transferred from the battery source to the pavement.

Variable Flux Technology: BYD’s "Adjusting" Rotors

BYD is addressing motor efficiency by altering the magnetic field itself, preventing the energy loss that typically occurs in permanent magnet motors at high speeds. Conventional permanent magnet synchronous motors have a fixed rotor flux that is highly efficient at low speeds but not as efficient at higher speeds (Leung, 2025). Similar to Variable Valve Timing (VVT), this motor has the ability to change the flux field dynamically to increase power conversion in a more manageable way. With managing the electric motor operation through a flux control mechanism, the ability of the power management system to lower power usage increases the mileage of the battery pack and increases the longevity of the high voltage drive components.  

Conclusion

The development of more efficient electric motor drivers is vital to a wider adoption of hybrid and EVs. Axial flux equipped vehicles are changing how electricity is converted to motion. Variable flux motors seem to be the best way forward within the automotive industry. Being able to provide power to those driving the vehicle no matter what the RPM is vital to a wider acceptability of an electric power train in their daily lives. It is a shift of thinking from a conventionally equipped vehicle that everyone has been using since they received their driver’s license to one of more efficient and controlled drivetrains. The psychological change of the populous that needs to occur will happen over a period of time and the manufacturers need to be ready for it when the demand increases. Developing this technology and others to meet those needs once they arrive will propel the industry forward in a grand new direction that the technician must be ready to repair.

The MAST series of CDX provides the instructor with pointed material to exceed the requirements of any ASE training currently on the market. Utilizing the Read-See-Do model throughout the series, the student has various learning modalities present throughout the products which allow them to pick the way they learn the best. From developing simulations on cutting edge topics to providing a depth of automotive technical background, CDX has a commitment to making sure instructors and students have the relevant training material to further hone their skill sets within the mechanical, electrical and software driven repair industry. CDX Learning Systems offers a growing library of automotive content that brings highly technical content to the classroom to keep you and your students up to date on what is currently happening within the Mobility Industry. Check out our Light Duty Hybrid and Electric Vehicles, along with our complete catalog.

About the Author

Nicholas Goodnight, PhD is an Advanced Level Certified ASE Master Automotive and Truck Technician and an Instructor at Ivy Tech Community College. With over 25 years of industry experience, he brings his passion and expertise to teaching college students the workplace skills they need on the job. For the last several years, Dr. Goodnight has taught in his local community of Fort Wayne and enjoys helping others succeed in their desire to become automotive technicians. He is also the author of many CDX Learning Systems textbooks, including Light Duty Hybrid and Electric Vehicles (2023), Automotive Engine Performance (2020), Automotive Braking Systems (2019), and Automotive Engine Repair (2018).

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The Evolution of Electric Motor Technology

by  Nick Goodnight, PhD     Feb 27, 2026
Electric Motor Technology

As the automotive world continues to transition to a version of an electric propulsion, electric drive unit (EDU) or motor generator unit (MGU) operation must increase its efficiency to keep up with the demand of the consumer. The electric motor present in the vehicle does more than just propels the vehicle. From providing power generation in deceleration mode or converting ICE mechanical power to electrical power, the motor generator unit/electric drive unit is a vital component to the transition of the industry towards sustainable propulsion. The efficient conversion of electrical potential into physical motion has been something the industry has been working on for decades. The development of automotive grade highly efficient motors is an area that is constantly being explored to increase conversion efficiency. This report will go over a couple of different configurations that are present in new vehicles and explains how they operate, while this is not an exhaustive list, these are the currently top of the line designs.  

Electric Motor Types

Axial Flux Motors

Axial flux drive motors (AFD) have a standard set gap between the stator and rotor which provides high torque at lower RPMs and decreased torque as speed increases (Yazdi et al., 2020). The gap is the amount of space between the rotor and the stator where the flux field intersects with the opposing fields to generate motion. Standard electric machines have larger rotors and stators to convert the electricity using a radial flux into mechanical motion. Axial motors have it packaged in a better way. These machines have permanent magnets situated in such a way as the flux runs parallel with the mechanical shaft in the motor which is part of the reason for their operation in a compacted state. In some applications a dual rotor machine with each rotor opposite each other allows for current coming into one rotor, travel to the opposing rotor and then back to the power supply (Yazdi et al., 2020). This setup allows for a very compact motor with a high torque output which permits the motor to be designed into a compact drivetrain efficiently.

Variable Flux Drive Motors

Variable flux drive motors (VFD) can adjust the power of the inductance based on how close the rotor to stator air gap becomes is directly related to the efficiency of the motor. In permanent magnet applications the inherent flux of the magnetic material provides for a strong low RPM operation that is highly efficient. As the rotor speeds increase the ability of the magnetic forces dwindle thus causing top end speed variations. The use of an AC VFD motor allows for adjustment of the field strength based on the speed/load of the motor. As the gap gets larger the efficiency of the motor increases on the high-speed operation and the alternate is true as the gap needs to be smaller to increase efficiency of the motor on low-speed operation (Arribas et al., 2024). Utilizing this technology to adjust the output of the motor depending on how exciting it allows the designers to create a compact motor that meets the varying needs of an automotive application going through the various operational speeds and demands (Tsunata et al., 2019). 

Ferrari’s first electric vehicle utilizes a quad-motor powertrain where the motors achieve staggering rotational speeds. Boasting a 210kW front axle motor with a 93% efficiency, the Elettrica has the ability to operate at performance level specifications on one single axle (Ferrari, 2026). The front and rear axles can be completely disconnected from each other which allows for higher efficiency and the ability to fit the needs of the situation and allows the driver to maintain total control. The front axle motor spins up to 30,000 rpm to produce 105 kW, while the rear motor reaches 25,500 rpm (Ferrari, 2026). Integrating the power electronics with each axle drive unit allows for a more compact package and less wiring needs. To minimize the size of these power electronics, the use of Silicon Carbide (SiC) provides for increased control and operational efficiency. To combat these high RPMs Ferrari employs a Halbach Array rotor configuration which uses segmented, surface mounted permanent magnets to boost torque density while keeping the assemblies’ weight lower than that of a conventionally designed motor. To sustain these speeds, Ferrari employs a Halbach array rotor configuration using segmented, surface-mounted permanent magnets to boost torque density while reducing weight. Furthermore, they utilize Litz wire windings in the stator to mitigate "skin and proximity effects," which typically cause energy loss at such high frequencies. Litz wiring uses individually wrapped conductors that are braided in a particular pattern to equalize current distribution throughout the circuit (Rubadue Wire, 2025). Making every component of the motor highly efficient allows more power to be transferred from the battery source to the pavement.

Variable Flux Technology: BYD’s "Adjusting" Rotors

BYD is addressing motor efficiency by altering the magnetic field itself, preventing the energy loss that typically occurs in permanent magnet motors at high speeds. Conventional permanent magnet synchronous motors have a fixed rotor flux that is highly efficient at low speeds but not as efficient at higher speeds (Leung, 2025). Similar to Variable Valve Timing (VVT), this motor has the ability to change the flux field dynamically to increase power conversion in a more manageable way. With managing the electric motor operation through a flux control mechanism, the ability of the power management system to lower power usage increases the mileage of the battery pack and increases the longevity of the high voltage drive components.  

Conclusion

The development of more efficient electric motor drivers is vital to a wider adoption of hybrid and EVs. Axial flux equipped vehicles are changing how electricity is converted to motion. Variable flux motors seem to be the best way forward within the automotive industry. Being able to provide power to those driving the vehicle no matter what the RPM is vital to a wider acceptability of an electric power train in their daily lives. It is a shift of thinking from a conventionally equipped vehicle that everyone has been using since they received their driver’s license to one of more efficient and controlled drivetrains. The psychological change of the populous that needs to occur will happen over a period of time and the manufacturers need to be ready for it when the demand increases. Developing this technology and others to meet those needs once they arrive will propel the industry forward in a grand new direction that the technician must be ready to repair.

The MAST series of CDX provides the instructor with pointed material to exceed the requirements of any ASE training currently on the market. Utilizing the Read-See-Do model throughout the series, the student has various learning modalities present throughout the products which allow them to pick the way they learn the best. From developing simulations on cutting edge topics to providing a depth of automotive technical background, CDX has a commitment to making sure instructors and students have the relevant training material to further hone their skill sets within the mechanical, electrical and software driven repair industry. CDX Learning Systems offers a growing library of automotive content that brings highly technical content to the classroom to keep you and your students up to date on what is currently happening within the Mobility Industry. Check out our Light Duty Hybrid and Electric Vehicles, along with our complete catalog.

About the Author

Nicholas Goodnight, PhD is an Advanced Level Certified ASE Master Automotive and Truck Technician and an Instructor at Ivy Tech Community College. With over 25 years of industry experience, he brings his passion and expertise to teaching college students the workplace skills they need on the job. For the last several years, Dr. Goodnight has taught in his local community of Fort Wayne and enjoys helping others succeed in their desire to become automotive technicians. He is also the author of many CDX Learning Systems textbooks, including Light Duty Hybrid and Electric Vehicles (2023), Automotive Engine Performance (2020), Automotive Braking Systems (2019), and Automotive Engine Repair (2018).

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References 

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