BYD had 4 patents detailing variable-flux permanent-magnet synchronous motor expertise, revealed by the China Nationwide Mental Property Administration (CNIPA) lately, following their submitting in Might 2024. The filings, CN121055622A, CN121055630A, CN121055623A, and CN121055631A, describe mechanisms for adjusting rotor magnetic flux to enhance effectivity throughout a variety of working speeds. These patents construct on BYD’s prior work in variable flux motor expertise and signify a technical evolution of the idea.
A Variable Flux Everlasting Magnet Synchronous Motor (VF‑PMSM) is a kind of motor during which the inner rotor magnetic flux will be adjusted in keeping with operational situations. Typical everlasting magnet synchronous motors have a set rotor flux, which gives sturdy torque at low speeds however reduces effectivity at greater speeds attributable to counter-electromotive forces. A VF‑PMSM dynamically regulates flux to take care of effectivity throughout low- and high-speed operation, enabling extra constant torque output and lowered vitality loss.
Flux adjustment is achieved by movable or controllable elements inside the rotor or magnetic circuit. At low speeds, magnetic flux is maximised to ship sturdy torque. At greater speeds, flux is lowered to minimise opposing forces and keep effectivity with out extreme vitality consumption. This strategy can enhance general vitality effectivity, lengthen high-speed vary, and optimise torque efficiency with out rising battery capability.
The 2025 BYD patents present sensible implementations of VF‑PMSM expertise. CN121055622A describes a magnetic-flux-adjustment element built-in with an electrical motor and drive system. CN121055630A describes a magnetic regulation element movable relative to the rotor to increase high-efficiency working areas. CN121055623A introduces an axial adjustment meeting that modifies rotor magnetic flux alongside its axis. CN121055631A presents a configuration during which the radial space of a magnetic conductive half will be adjusted, permitting fine-tuning of inner flux. All technical descriptions correspond to CNIPA abstracts, making certain verifiable accuracy relating to magnetic flux regulation mechanisms and rotor designs.
Along with these three VF‑PMSM patents, BYD filed and revealed different 2025 patents associated to electrical motor buildings and drive techniques. These filings embody rotor and stator {hardware} designs, magnetic flux administration elements, and different motor-related improvements. The general public patent report signifies that BYD’s analysis and growth in motors and powertrain techniques is ongoing. Nonetheless, no further public experiences affirm industrial deployment or experimental outcomes particularly for VF‑PMSM expertise.
For electrical automobiles and different new vitality automobiles (NEVs), VF‑PMSM expertise can enhance effectivity throughout a variety of driving situations. By adjusting rotor magnetic flux, these motors cut back vitality loss at excessive speeds, lengthen driving vary, and keep constant torque at low speeds. This enables extra predictable vitality consumption throughout lengthy journeys, reduces thermal stress on motor elements, and optimises battery utilization for each totally electrical and hybrid powertrains.
Collectively, the patents illustrate BYD’s ongoing growth of high-efficiency motors able to variable-flux management, addressing a limitation of fixed-flux permanent-magnet motors.
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