Virtual Inertia Control and Small-Signal Stability Analysis of Electric Vehicle

In electric vehicles (EVs), the small size of the dc link capacitor results in significant voltage deviations when there are changes in load or uncertain fluctuations from the power resources. This causes a decline in voltage quality. To address the issue of low inertia, this study suggests the use of a fast-responding energy storage system, such as a supercapacitor (SC), which can replicate inertial responses through a specified control algorithm. A virtual capacitor and a virtual conductance are presented in this paper, which are implemented in the inner loop control, specifically the current loop control of SC, to effectively emulate inertia and damping and improves the battery lifetime by reducing the rate of charge and discharge. To assess the stability of the EV, a comprehensive small-signal model is developed, and the acceptable range of inertia response parameters is determined through eigenvalues analysis of the system. Numerical simulations are conducted to demonstrate the performance of the proposed control structure.