BYD Files New Patents for Variable-Flux Motor Technology to Improve EV Efficiency and Range

Chinese electric vehicle manufacturer BYD has submitted four new patent applications to the China National Intellectual Property Administration (CNIPA), focusing on advanced variable-flux permanent magnet synchronous motor (PMSM) technology. This innovation enables dynamic adjustment of the rotor’s magnetic flux to improve performance and energy efficiency across different driving conditions. Traditional permanent magnet motors rely on a constant magnetic field, which provides strong torque at low speeds but causes energy losses at higher speeds due to increased counter-electromotive forces. BYD’s variable-flux system addresses this limitation by actively modifying magnetic intensity within the rotor based on speed and load, reducing unnecessary energy consumption and improving overall efficiency.

The patents describe several technical approaches, including integrating flux-control components directly into the motor and drive system, or using movable magnetic elements that adjust their position relative to the rotor. Other methods involve controlling magnetic flux distribution along the rotor axis or modifying magnetic conductive surfaces to fine-tune performance. These strategies collectively expand the motor’s high-efficiency operational range and optimize energy use during low- and high-speed operation.

This advancement builds upon BYD’s existing research into variable-flux technology and marks another step toward more efficient, durable, and range-extending electric drivetrains. The technology promises reduced energy loss, improved torque stability, lower heat buildup, and better battery resource utilization in both fully electric and hybrid vehicles, reinforcing BYD’s position as an innovation leader in the EV sector.