Robust control can maintain robust stability and robust performance for an inductive power transfer (IPT) system in a comparatively larger perturbation range of parameters. However, it ignores the transient performance… Click to show full abstract
Robust control can maintain robust stability and robust performance for an inductive power transfer (IPT) system in a comparatively larger perturbation range of parameters. However, it ignores the transient performance requirements and influence of open-loop properties on a resulting controller. So a method of improving two-degree-of-freedom (2DOF) H$\infty$ robust control for the IPT system is proposed. Based on the generalized state-space averaged model, the distribution of poles and zeroes under mutual-inductance and load perturbations with a bounded range is investigated in detail. An expected closed-loop transfer function is added in a 2DOF control structure with a prefilter and feedback controller, to introduce the transient performance requirements. Then, a generalized plant including the model of the IPT system is defined and its state-space realization for standard robust control configuration is also derived. Finally, controllers with different performances are designed referring to the mutual-inductance and load features. Simulation and experiment results show that the 2DOF H$\infty$ robust controller designed with parameters that maximize the modulus value of a dominant pole can reach the prescribed performances for the IPT system, with settling time and overshoot of no more than 5 ms and 2% in startup and reference tracking processes, and restoring time of no more than 5 ms when parameter perturbation occurs.
               
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