Parallel Operation Dual-Output Inverters with PR Control for Railway Signal Power Systems

A dual-output inverter is presented to meet the demand of railway signal power systems. The PR control is adopted to achieve zero steady-state error tracking of voltage reference and to suppress the disturbance of output current. A parameter design method based on the closed-loop dominant pole configuration is given to deal with the high order of PR closed loop system. In addition, this paper proposes an improved control method for parallel-operated inverters. Synchronous control and current sharing control are used to ensure the stable parallel operation with low circulating current. A 2000 VA prototype is built to verify the superiority of the PR control and the feasibility of the parameter design method. The presented parallel-operated strategy can also realize the current sharing between inverters effectively.