A DC-Link Voltage Fast Control Strategy for High-Speed PMSM/G in Flywheel Energy Storage System

This paper presents a dc-link voltage fast control strategy for high-speed permanent magnet synchronous motor/generator of flywheel energy storage system (FESS) to ensure fast dynamic performance within its wide operation range. Instead of the conventional strategy with cascaded outer dc-link voltage loop and inner current loop, the proposed strategy is a direct voltage control strategy without an intermediate current loop. The nonlinear dc-link voltage loop model is globally linearized by treating the square of dc-link voltage as the state variable, and lumping the nonlinear and uncertain terms in the power balance equation as the total disturbance. An extended state observer (ESO) is designed to observe the total disturbance, and a control law that compensates the speed variation and the total disturbance is proposed. The inner dynamic of the proposed ESO is analyzed, and the tracking performance and antidisturbance capability of the proposed strategy is hereby derived. Finally, the proposed strategy is validated on a high-speed FESS test bench.