‘Virtual magnet’ claims reveal why EVs need their rare-earths, Pg2

Key Highlights:

• Vimag Labs, a Bengaluru-based startup, claims to have developed "virtual magnets" to replace rare-earth magnets in electric vehicle (EV) motors.
• This technology utilizes copper coils and software to generate and control magnetic fields, aiming to reduce reliance on critical rare-earth materials.
• The innovation addresses the challenge of high efficiency in EVs, which is currently largely dependent on Permanent Magnet Synchronous Motors (PMSM) that use rare-earth magnets.
• Vimag Labs recently secured an Indian patent for its Virtual Magnet Synchronous Motor (VMSM) architecture.

Detailed Insights:

• Electric motors convert electrical energy into mechanical motion, while generators perform the reverse, both relying on magnetic fields.
• The core components of an electric motor are the rotor (the rotating part) and the stator (the stationary part).
• Large-scale power generators, such as those in hydroelectric, thermal, and nuclear plants, have historically used electromagnets, which are copper coils supplied with Direct Current (DC).
• The brushless excitation system is a technology that allows continuous DC supply to the rotating coils in large generators by integrating a rectifier on the rotor itself.
• Vimag Labs' "virtual magnet" system does not create magnetism from software but rather uses software to precisely regulate the current flowing through electromagnets, thereby controlling the magnetic field's strength and direction.
• While permanent magnets establish a magnetic field without continuous electrical energy input, electromagnets require energy for both field generation and modulation, potentially leading to efficiency losses.
• Permanent Magnet Synchronous Motors (PMSM) are dominant in the EV market due to their high efficiency, which directly impacts vehicle range and allows for smaller, lighter battery packs.
• Other alternatives to permanent magnets, such as Switched Reluctance Motors (SRM), are being explored by companies like Honda and Hitachi Astemo to eliminate rare-earth dependency, but they face challenges with efficiency and noise.
• Even a marginal increase in motor drive efficiency (e.g., 0.1%) can significantly improve an EV's range and reduce the overall weight and cost of the vehicle by allowing for a smaller battery.

Scientific/Technical Concepts Involved:

• Electric Motor: A device that converts electrical energy into mechanical energy through the interaction of magnetic fields.
• Electromagnet: A temporary magnet created by passing an electric current through a coil of wire, typically wound around a ferromagnetic core.
• Permanent Magnet Synchronous Motor (PMSM): An AC motor where the rotor's magnetic field is produced by permanent magnets, offering high efficiency and power density, often using rare-earth materials.
• Switched Reluctance Motor (SRM): A type of electric motor that operates on the principle of reluctance torque, with no permanent magnets or windings on the rotor, making it mechanically simple.
• Rare-earth magnets: Powerful permanent magnets made from alloys of rare-earth elements, crucial for high-performance applications like EV motors and wind turbines due to their strong magnetic fields.