<span lang="EN-GB">The paper is focused on the tram input LC traction filter stabilization by the Energy Storage System. The input LC filter is almost undamped resonant circuit which is mainly excited by the motor constant torque command. The tram during voltage drops increases the current flow from the LC filter to hold constant torque and thereby further decreases the LC filter voltage, and vice versa. This could lead to unstable traction drive behaviour. The Energy Storage System can be used to stabilize LC filter voltage.</span>