Analysis and control optimization of positive pressure fluctuation in electromechanical oxygen regulator

The Electromechanical Oxygen Regulator(EMOR)is a new type of aviator oxygen equipment.Positive pressure refers to the pressure difference between the breath pressure and the ambient pressure during pressurized oxygen supply.The phenomenon of positive pressure fluctuation was believed to reduce the system performance.The current open-loop control method cannot solve this problem.In this paper,the mathematical model was established and main factors were analyzed.By combining experimental research and simulation calculation,it was determined that pressure fluctuation was caused by inlet pressure and diaphragm deformation together.With the increase of pulmonary ventilation volume,the influence of inlet pressure on fluctuation decreases gradually,while the proportion of diaphragm deformation increases rapidly.A closed-loop control strategy of Proportional Resonant with Feedforward Compensation(PRFC)was proposed to solve the problem and control parameters were obtained through co-simulation.The effectiveness of the control strategy was verified by experiments.The results show that the control strategy can enhance the anti-disturbance ability of the system and significantly reduce the pressure fluctuation range,which is beneficial to improving the overall system performance.

Active and Reactive Power Decoupling Control of Grid-Connected Inverters in Stationary Reference Frame

Proportion resonant(PR)controllers are able to achieve zero steady-state error for AC input signals and are widely used for simplifying control systems in the stationary reference frame.However,power decoupling in the stationary reference frame with a PR controller has not been investigated thoroughly.Based on the complex vector model of a grid-connected inverter(GCI),this paper deduces theoretically the power coupling relationship of GCI with the traditional PR current controller.A modified PR controller is provided for achieving the power decoupling,and the design method of the controller is presented.Simulation and experimental results verify that there is coupling between active and reactive power using the traditional PR controller and the proposed method can realize the power decoupling.