Control of electrolyte flow rate for the vanadium redox flow battery by gain scheduling

In this article, a gain scheduling approach is proposed to control the electrolyte flow rate for a VRB system. The flow rate is regulated to ensure that the open circuit voltage difference before and after cell stack tracks a given reference trajectory. The nonlinear process model is linearised around three different operating points with different state of charge. A set of PI controllers have been designed based on the linearised process model for both charging and discharging. To improve the control performance, a feedforward controller is designed to compensate the effect of current fluctuations. Simulation studies have been conducted under different operating conditions to demonstrate the performance of the proposed approach.