China's BYD files patent for motors that promise longer EV range

China’s electric vehicle manufacturer BYD has filed four new patents with the China National Intellectual Property Administration (CNIPA) for variable-flux permanent magnet synchronous motor technology. These patents describe technical methods to dynamically adjust the magnetic flux in the motor’s rotor, allowing the motor to operate more efficiently across varying speeds and load conditions. By actively managing the magnetic intensity, the motor can reduce energy losses at high speeds while maintaining strong torque at low speeds, enhancing overall drivetrain performance and efficiency. The variable-flux motor design differs from conventional permanent magnet motors by enabling the magnetic field strength inside the rotor to be altered depending on operating conditions. This adaptability helps optimize torque and efficiency: increasing magnetic flux at low speeds for higher torque, and reducing it at high speeds to limit opposing electromagnetic forces and conserve energy. BYD’s patents detail practical engineering solutions, such as adjusting magnetic flux along the rotor’s axis or modifying magnetic conductive areas, to realize these benefits. The technology promises longer EV driving ranges, improved energy use predictability