Rotary fluid device with multi-level phase shift control

摘要

A method for controlling a rotary fluid device includes providing a rotary fluid device having a fluid displacement assembly and a plurality of control valves. The fluid displacement assembly includes a first member and a second member. The first and second members have relative movement and define a plurality of volume chambers. The plurality of control valves is in fluid communication with the plurality of volume chambers. A desired displacement is received. A relative position of the first and second members is determined. An optimal displacement family is selected from a plurality of displacement families that is based on peak displacements of a plurality of displacement curves. A phase shift angle for the optimal displacement family is selected so that an actual displacement of the fluid displacement assembly approaches the desired displacement. The control valves of the rotary fluid device are actuated in accordance with the phase shift angle.