Axial Flux Motor Helps Generator Manufacturer Improve Off-Grid Charging

A manufacturer of generators—medium-sized, fixed gensets primarily designed for independent or grid-supplement electric vehicle (EV) charging—needed help. These generators are grid-independent and scalable. They generate efficient power, ensuring seamless operation in critical infrastructure and sustainable mobility applications The manufacturing team required an electric motor to operate as permanent magnet generator (PMG) in the generators/chargers.

Technical Challenge

The space in the compact charger was limited, and its weight needed to be less than 500 kilograms. The generator had to be power dense to support the device’s operation.

Solution

A component manufacturer partnering with the generator team suggested an axial flux motor with a double stack layout. This motor, because of its design, provided excellent torque and power at low revolutions, which made it ideal for this generator application. The selected motor’s specifications were:

• Maximum speed – 3,700 rpm
• Continuous maximum torque –  375 Newton meters (Nm)
• Maximum torque, at 20 seconds (s) – 875 Nm
• Continuous maximum power 120 kilowatts (kW)
• Maximum power, at 20 s, – 310 kW
• Maximum continuous current –  220 A_rms

The axial flux motor was the ideal solution for the limited space because of its short axial length and high power density.

Results

During rigorous testing and validation, the axial flux motor’s performance exceeded the generator manufacturer’s expectations. As a result, the team can demonstrate the power of their next-generation device with the axial flux motor (acting as a PMG) to major electric-vehicle fleets globally.