Stator electromagnet
The armature winding itself, the excitation source every synchronous machine already carries.
Technology
Excitation is a design variable, not a material constraint.
Two layers matter here. The Universal Synchronous Machine is the machine family: a generalized formulation with three design knobs — excitation sources, geometry and saliency, and flux direction. The Universal Synchronous Motor Drive is the product: machine, power converter, energy source and control designed as one system. The drive is what we sell. The machine is what makes the drive possible.
01 — Excitation as a design variable
Every conventional motor is a special case of one formulation.
Conventional practice fixes the excitation source — a permanent magnet — and designs everything else around it. The generalized formulation admits four independent flux sources and treats the allocation between them as an optimization variable. Surface mount PMSM, interior PMSM, wound field synchronous and synchronous reluctance machines all fall out of the same formulation as special cases: points in a design space, not separate product categories. The design question stops being which motor type to buy and becomes which allocation of excitation meets the requirement with materials you are willing to depend on.
Stator permanent magnet
Fixed flux contributed from the stationary side, available where geometry favors it.
Rotor permanent magnet
The conventional choice. In this architecture it is ferrite, not a rare earth compound, and it is one contributor among several rather than the whole design.
Rotor wound field
A controllable field source. Field strength becomes a dynamic quantity the drive commands, not a property frozen into a material at magnetization.
02 — Saliency as recovered torque
The torque a surface mount design throws away, engineered back in.
The average torque of a synchronous machine decomposes into two parts: an excitation term, from the interaction of rotor flux with stator current, and a reluctance term, from the rotor’s preference to align its easy magnetic axis with the stator field. A surface mount permanent magnet design has little saliency, so it produces almost no reluctance torque — that term is left on the table. Engineering the rotor geometry to raise the saliency ratio brings the reluctance term into play, and in our modelling that recovery is what closes most of the gap left when a rare earth magnet is replaced with ferrite.
85–95%
of the torque density of an equivalent NdFeB permanent magnet machine, using exclusively non rare earth materials. This is a modelled design target, not a measured result.
03 — One system, not three
Machine, converter and control, designed together.
Multiple excitation sources need coordinated current allocation, and that is a control problem, not a machine problem. The drive carries the estimation, allocation and fault handling that make the machine practical: continuously allocating the controllable stator and field currents to meet torque demand, given the fixed magnet flux and the coupling between sources, and reconfiguring that allocation when conditions change. A wound field can be strengthened or weakened on command, which a magnet cannot, and it cannot be permanently demagnetized by a fault current or a thermal excursion, which a magnet can. Because the coordination lives in control rather than in geometry, the same structure instantiates across power levels — the architecture scales from small aerial platforms to traction without being redesigned from scratch.
Why this matters now
High performance motion control is built on a concentrated supply chain.
The compact, high performance end of motion control converged on permanent magnet synchronous machines, and the high torque density designs assume rare earth magnets — primarily neodymium iron boron. Rare earth elements are not geologically rare; the constraint is industrial. The chain that turns ore into finished magnets is dominated by a single country, most heavily in chemical processing and magnet manufacturing. An architecture that reaches permanent magnet class performance without rare earth magnets removes that exposure at the design level, rather than hedging it at the procurement level. Ferrite, copper and iron are available everywhere, from many suppliers, at stable prices.