Development of a new uninterruptible power supply using flywheel energy storage techniques

Abstract

An uninterruptible power supply (UPS) with a flywheel for an energy storage unit is described. An electrical main circuit consisting of a half-bridge converter, a symmetrical half-bridge inverter, and an inverter/converter is used to drive the flywheel induction motor/generator. Charging or discharging control of the mechanical energy is achieved by controlling the slip frequency of the induction machine. The converter is controlled by a current follow-up method using a hysteresis comparator to get the sinusoidal input current and the unity power factor. The inverter is controlled to obtain the sinusoidal voltage by using a voltage follow-up method. Experimental results are given.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>