An Optimization Control Strategy for an Energy Storage Inverter in Grid-connected Zinc-Bromine Flow Battery System Based on Trust-Tech Method

In order to increase the response speed and the power quality of an energy storage inverter in grid-connected wind power system, an optimization control strategy has been proposed based on the transformation under stability-retraining equilibrium characterization (Trust-Tech). The core work is to derive a Trust-Tech framework for rapid optimizing the proportion coefficient and integral coefficient of the inverter based on modelling the zinc-bromine flow battery system which is used in energy storage of wind energy. Due to the output voltage is controllable, the zinc-bromine flow battery system is used to stabilize the bus voltage of the inverter. It can promote the dynamic index and stable index of the energy storage inverter and corresponding optimization rule has been given. Simulation and experiment results show that the total harmonic distortion of the voltage and current (THD
u
and THD
i
) and of the energy storage inverter can be controlled within 4% and 6% which are the permitted upper limit of the standard GB/T-14549-93. Moreover, the response period of the inverter is less than 10ms which can reach the control requirement of the grid-connected wind power.