Highlights

• Permanent magnet synchronous motors (PMSMs) dominate EV design with superior efficiency and power density, but their reliance on rare-earth magnets creates supply chain vulnerabilities concentrated in China.
• Wound rotor synchronous motors (WRSMs) are emerging as a strategic alternative, eliminating rare-earth dependency while delivering competitive real-world efficiency in urban and commercial applications.
• A comprehensive peer-reviewed study spanning 2006-2025 confirms that EV motor selection has evolved from pure engineering optimization to a critical supply-chain and geopolitical decision.

---

A new peer-reviewed study led by Ahmet Orhan (opens in a new tab) of Fırat University (opens in a new tab), with collaborators from the same institution, delivers a clear verdict on electric-vehicle motor design—while quietly exposing a growing supply-chain fault line. Published in Dicle University Journal of Engineering (DUJE, Vol. 16, Issue 4, 2025), the study confirms that permanent magnet synchronous motors (PMSMs) remain the dominant choice across most EV segments due to their superior efficiency and power density. But it also highlights why wound rotor synchronous motors (WRSMs) are gaining renewed attention: they eliminate reliance on rare earth elements, a market still overwhelmingly processed in China.

Put simply, EV makers prize efficiency—but geopolitics is now reshaping what “optimal” really means.

Why EV Motors Matter to the Rare Earth Supply Chain

Electric motors are the beating heart of an EV. Their design directly influences range, energy consumption, cost, acceleration, and vehicle positioning. Today’s leading PMSMs rely on rare-earth permanent magnets—especially neodymium and dysprosium—materials whose mining, processing, and chemical separation are highly concentrated in China.

The DUJE study does not set out to analyze geopolitics. Yet its technical findings underscore an unavoidable reality: motor architecture choices are inseparable from rare-earth supply risk.

Study Scope and Methods

The authors conducted a systematic comparative review spanning nearly two decades (2006–2025) of peer-reviewed research and real-world EV data. Drawing from IEEE Xplore, Scopus, ScienceDirect, and Google Scholar, they evaluated four major EV motor architectures:

• Permanent Magnet Synchronous Motors (PMSM)
• Wound Rotor Synchronous Motors (WRSM)
• Induction Motors (IM)
• Brushless DC Motors (BLDC)

Motor performance was assessed across power output, efficiency, power-to-weight ratio, energy consumption, vehicle segment (economy, mid-range, luxury, commercial), and real-world driving range.

Key Findings: Efficiency vs. Supply Security

PMSMs: Best-in-Class Performance—with a Hidden Dependency

PMSMs consistently deliver the highest power-to-weight ratios (typically ~2–3 kW/kg) and excellent efficiency, making them the default solution for mid-range and high-performance EVs. Models such as the Tesla Model 3 illustrate how PMSMs can combine strong acceleration with relatively modest energy consumption.

The trade-off is structural: PMSMs depend on rare-earth magnets, locking EV production into a supply chain where China dominates downstream processing and separation. As EV volumes scale, that dependence becomes harder to ignore.

WRSMs: Lower Peak Density, Higher Strategic Value

WRSMs replace permanent magnets with electrically excited rotor windings. While they typically exhibit lower peak power density and slightly lower maximum efficiency, they offer three decisive advantages:

• No rare earth materials required
• Excellent field-weakening capability, enabling wide speed ranges
• High thermal tolerance, especially under variable load conditions

The study highlights WRSM deployment in vehicles such as the Renault Zoe and notes broader OEM interest, including from BMW. Over full driving cycles—not just peak output—WRSMs can deliver competitive real-world efficiency, particularly in urban, fleet, and commercial use cases.

Induction Motors and BLDC: Purpose-Built Niches

Induction motors remain attractive for heavy-duty and commercial EVs due to durability and cost advantages, though they generally trail PMSMs in efficiency. BLDC motors dominate low-power and micromobility segments, but scale poorly into high-power passenger or commercial platforms.

Segment-Level Insights That Matter

• Economy and urban EVs achieve the highest km/kWh thanks to low vehicle mass and modest power requirements.
• Mid-range EVs strike the most balanced trade-off between performance and efficiency—driven largely by PMSMs.
• Luxury and high-performance EVs prioritize torque, acceleration, and comfort,

Limitations and Open Questions

The authors acknowledge important constraints:

• This is a comparative review, not a new experimental validation.
• WRSMs still face challenges in cooling, excitation losses, and control complexity.
• Maintenance concerns linked to slip rings—though mitigated by emerging brushless designs—remain relevant.

Commercial adoption of WRSMs is still limited, and scaling them into mass-market EVs will require continued innovation.

Conclusion: Motor Architecture Has Become a Strategic Choice

The DUJE study captures a shift already underway in the EV industry: motor selection is no longer just an engineering optimization—it is a supply-chain decision. PMSMs remain the efficiency benchmark, but their reliance on rare-earth magnets ties EV growth to China’s processing monopoly. WRSMs, while not a universal replacement, offer a viable alternative aligned with sustainability goals and geopolitical risk reduction.

For automakers, investors, and policymakers, the message is unmistakable: the future of EV motors will be shaped as much by materials security as by performance metrics.

Citation: Orhan, A.; Ünal, S.; Akbal, A.; Doğan, K.; Kayaoğlu, M.; Bıyık, H. Trends in Electric Vehicle Motor Power: A Comparative Study on Performance and Efficiency. DUJE – Dicle University Journal of Engineering 16(4), 2025, pp. 901–918. https://doi.org/10.24012/dumf.1755155 (opens in a new tab)

© 2025 Rare Earth Exchanges™ – Accelerating Transparency, Accuracy, and Insight Across the Rare Earth & Critical Minerals Supply Chain.