Current regulators for multi-phase permanent magnet spherical machines

Robot manipulators usually have several series connected drives to achieve several degrees of freedom. In the following, a power converter for a novel spherical machine is presented which offers three degrees of freedom. This spherical motor requires a power converter that controls each stator coil individually because the rotor pole pitch can vary during operation. It is shown how the converter legs influence each other and which design aspects have to be considered. To evaluate the spherical motor converter, a planar motor with three degrees of freedom was developed and tested using the multiphase power converter