In this paper, a new decentralized gradient-based cooperative control method is proposed to achieve current sharing for parallel chargers in energy storage-type light rail vehicle systems. By employing a generalized artificial potential function to characterize the interaction rule for subchargers, the current-sharing control problem is converted into an optimization problem. Based on the gradient of the potential function, a decentralized gradient cooperative control law is derived. A general saturation function is introduced in the proposed control to guarantee the boundedness of the control output. The stability of the closed-loop system under the proposed decentralized gradient control is proven with the aid of a Lyapunov function. Simulation results are provided to verify the feasibility and validity of the proposed distributed current-sharing control method.