Virtual current representation of magnetic fields for electric motor design

Simulating a magnetic field within an electromagnetic device, e.g. a motor having a stator (220 fig 2) and rotor (210, fig 2), for use in evaluation e.g. finding optimal magnetic field design. The computer-implemented method comprises obtaining a digital design of the electromagnetic device (preferably a motor with stator and rotor, or generator). The digital design representing geometric and material properties of the electromagnetic device (examples preferably may include: shape, orientation of coils, and electrical, magnetic or thermal properties). Obtaining magnetic field data which represents a magnetic field pattern that would be generated through operation of the digital design 122. The conversion of the magnetic field data into virtual current data 124, representing the magnetic field pattern as one or more virtual currents (240, fig 2) that create an estimated magnetic field pattern that would match the magnetic field pattern. Preferably, one or more performance parameters (e.g. torque, magnetic field strength) are determined based on the virtual current data 126 and an updated digital design of the electromagnetic device is output preferably for subsequent use in optimisation steps to improve performance parameters. Preferably, the updated or optimal digital design is used for manufacturing purposes.