Research On Fiywheel Energy Storage System And Its Controlling Technique

Flywheel energy storage (FES) system depends on high-speed flywheel and stores kinetic energy. It has such merits in the field of energy storage as high efficiency, long life and no environmental pollution. Before the 80抯, the FES technology developed slowly because of many unsolvable problems such as the driving of high-speed flywheel, the high-efficient energy converting, the friction of flywheel bearing and the loss of wind- resistance. Now, with the further development of modern power electronics and high temperature superconductive magnetic bearing and the discovery of new high-intensity materials (e.g carbon fibre and fibreglass), the FES technology will make a breakthrough and come into utity. Based on new development of the research in the FES system, this paper presents a study in FES system design applying to power system. Physical Model of FES experimentation system is devised and its control methods are presented according to the optimal operation of power system. The FES experimental system is composed of four parts: the flywheel that stores energy, the bearing that supports the flywheel, the motor/generator and the AC power converter regu4ated by a microprocessor controller. The AC power converter consists of t inverters, one for the motor/generator and the other for power systems. In this paper, a numerical modal of asynchronous motor is derived from its mathematical modal in a -/1 coordinate system and it is used to simulate the dynamic procedure of motor/generator. A FES system design for distribution network is given and the PID voltage regulator of this system is analyzed. When many FES systems are installed in power system, a numerical optimal calculation about reactive power supplying is presented in this thesis. The optimal distributing rule, operating all amount of supplying reactive power at equal incrementa4 toss, is derived from a simple cause and effect. The Newton-Raphson method of solving the load-flow problem is used in calculation, so the power flow equations are always equal. This paper presents studies on experiments of the FES system storing energy and synchronous operating with power system.