Excitation of cycloidal electric machine

An electrical system comprising:

• a direct current (DC) voltage bus;
• an alternating current (AC) voltage bus;
• a power inverter module (PIM) connected to the DC voltage bus and to the AC voltage bus;
• a polyphase cycloidal rotary electric machine connected to the PIM via the AC voltage bus, and having a stator and a rotor with respective stator and rotor axes, wherein the rotor axis is eccentric with respect to the stator axis, an airgap is defined between the stator and the rotor that is smaller at an instantaneous center of rotation of the rotor than elsewhere around a circumference of the rotor, and the rotor moves with two degrees of freedom (2DOF), the 2DOF including rotating motion about the rotor axis and orbiting motion about the stator axis;
• a position sensor configured to measure an angular position of the rotor, and to output a rotor position signal indicative of the angular position;
• a plurality of current sensors connected to the AC voltage bus and configured to measure phase currents to the rotary electric machine, and to output a set of current signals indicative of the phase currents;
• and
• a controller configured to receive a set of input signals, including a torque command, the rotor position signal, and the set of current signals, and responsive to receipt of the input signals, to:
• identify an optimal stator pole or pole pair located proximate the instantaneous center of rotation of the rotary electric machine;
• energize the optimal stator pole or pole pair via the PIM prior to energizing another stator pole or pole pair of the stator to generate maximum torque per unit amp;
• and
• alternate, in response to the torque command being an increasing torque command in which the input signals are indicative of a transition between a partial-load operating condition and a peak-load operating condition, an energizing of at least two of the stator phases with an energizing of a multiple of the at least two stator phases.