Design and Optimization of a Two-Degrees-of-Freedom Current Control Scheme

A control scheme having two degrees of freedom is designed so that many issues such as disturbance and set-point response, model uncertainties and measurement noise are taken into account. For optimization of the disturbance performance a pole placement approach is combined with the minimization of the integrated error (IE). A feedforward compensator based on an inverse dynamic model of the plant gives the desired set-point response. Robustness is examined using the sensitivity function and the Nyquist plot. Design parameters are introduced allowing an engineer to trade-off between the conflicting objectives. Simulation results and experimental results of a current control loop are discussed. The proposed scheme is not limited to this application area.