Applying flywheel energy storage system to integrated power system for power quality and stability enhancement

The integrated power system (IPS) is an integral electrical platform used for power generation, daily electricity demand, electric propulsion, power supply for high-energy weapons and high-power detecting devices, and represents the trend of developing modern vessel power systems. As the IPS with stiff, high-order, nonlinear, strong-coupling characteristics is vulnerable to the system transients, a flywheel energy storage (FES) system is introduced, which is composed of an induction machine, a flywheel and a bi-directional converter. The FES is connected to the DC bus of IPS in parallel. The control strategy based on the field oriented space vector pulse width modulation (SVPWM) is proposed and a simulative model of the simplified DC IPS containing FES is established in PSCAD/EMTDC in order to test the efficiency of the FES. A short-time trip to the generator and a sudden application of load are simulated, and the static stability and transient stability are studied by applying constant-power load and fault to IPS, respectively. The study shows that the FES can switch its operating modes automatically by this strategy to adjust the DC bus voltage and to compensate the power unbalance between generators and loads. Using FES, the DC bus fluctuation can be restrained and the power quality and the stability of the IPS can be improved effectively.