A new large-diameter, permanent magnet motor line is currently under design for very low speed (2 rad/sec), high-precision (10 urad) applications. For a
3-phase motor, torque ripple is ~7%, with ripple inversely proportional to the number of phases.
An attractive alternative to the standard 3-phase controller is an FPGA multi-phase controller where each stator coil is individually controlled. For the preliminary design, somewhere in the range of 30 stator coils will be utilized.
Has anyone had any experience in using an FPGA for this type of application? Commercial drivers are primarily based on either trapezoidal or sinusoidal commutation schemes, and it would seem that since each coil could be individually controlled, either scheme could be readily implemented. Commercial and open cores all seem to be based on the standard 3-phase windings.
If any individuals with experience in this area would be interested in working on a project such as this on a consultant basis, kindly send a brief description of relevant experience and a contact number or email address to jjacob @ acm-nevada . com (without spaces).
Jon Jacob ACM Nevada