BYD's Breakthrough VF-PMSM Patents Revolutionize EV Motors

BYD, China's EV powerhouse, has unveiled four key patents for Variable Flux Permanent Magnet Synchronous Motor (VF-PMSM) technology, published by China's National Intellectual Property Administration (CNIPA) in December 2025 after filing in May 2024. These innovations (CN121055622A, CN121055630A, CN121055623A, CN121055631A) enable dynamic rotor magnetic flux adjustment, boosting efficiency across low- and high-speed operations. This move signals BYD's aggressive push to outpace competitors in motor tech, potentially extending EV range without larger batteries.

What is VF-PMSM Technology?

Traditional permanent magnet synchronous motors (PMSMs) dominate EVs like Tesla's but suffer fixed flux limitations: powerhouse torque at low speeds, yet efficiency drops at highway paces due to back-EMF (counter-electromotive force). VF-PMSM solves this by dynamically tweaking rotor flux:

• Low speeds: Maximize flux for peak torque.
• High speeds: Reduce flux to cut losses and sustain efficiency.

Benefits include:

• Up to 10-20% efficiency gains (based on industry benchmarks from similar tech).
• Extended high-speed range.
• Optimized torque without battery upsizing.

BYD's patents detail practical rotors: movable magnetic regulation components (CN121055630A), axial flux adjusters (CN121055623A), and radial magnetic conductive tweaks (CN121055631A).

Patent Breakdown: BYD's Technical Edge

These build on BYD's prior variable flux work, with ongoing filings in rotors, stators, and powertrains underscoring relentless R&D.

Comparison to Western EV Motor Tech

Western giants lag in variable flux adoption:

• Tesla: Relies on high-efficiency fixed PMSMs (e.g., Plaid's carbon-wrapped magnets), hitting 95%+ peak efficiency but flux-weak at extremes. No public VF-PMSM patents.
• Lucid: Advanced axial-flux motors claim 20% range edge, yet fixed flux limits versatility.
• GM/Rivian: SiC inverters boost efficiency, but motors stick to conventional PMSMs.

BYD's approach mirrors its Blade Battery dominance—cost-effective, scalable innovation from China's supply chain.

Global Implications: Why This Matters for EVs

BYD's VF-PMSM patents intensify China's EV lead, where it commands 35%+ global BEV/PHEV share (2024 CnEVPost data). For Western readers:

• Range Anxiety Killer: Efficiency gains could add 30-50 miles real-world range, rivaling solid-state battery hype.
• Cost Pressure: Patents enable cheaper motors (rare earths optimized), undercutting Tesla's $40k+ pricing.
• Tech Race: No commercial VF-PMSM yet, but BYD's Seagull/Han models may integrate by 2026, pressuring GM/Ford to innovate.

This fits China's 2024 patent surge (60% of global EV filings), fueling exports like BYD's Brazil/Ukraine plants.

Looking Ahead: BYD's Next Powertrain Leap

Expect VF-PMSM in 2026+ models, paired with e-Platform 3.0's 800V SiC. If efficiency hits 97% system-wide, BYD could claim 600+ km WLTP ranges at sub-$20k prices—global disruption incoming. Watch for prototypes at Auto Shanghai 2025. Western OEMs: innovate or import?