Speed Ripple Cancellation in a Rolling Piston Compressor via a Nonlinear Adaptive Speed Controller

摘要

The common refrigeration cycle requires a compressor unit to transition the working gas from low to high pressure. In applications where noise and vibration mitigation are desired there is motivation to achieve high fidelity speed regulation. This speed control is made difficult by the fact that as the gas is compressed it exerts a highly nonlinear force against the compressor piston. Though this effect is common to all compressors, the present work considers a rolling piston type rotary compressor. A nonlinear controller is proposed which utilizes the known geometries of a rolling piston compressor, as well as the thermodynamic properties of the working gas, to develop an adaptive load torque observer. This observer acts as a feedforward term in the control input to effectively cancel out the speed ripple induced by the load torque. This design is motivated by a Lyapunov-based stability analysis which proves that the combined controller and observer scheme reduces speed error to zero asymptotically. Simulation results provide further validation.