This paper proposes a control scheme for single phase inverter based systems. The inverter controller consists of two loops; the inner current control loop which is the faster one while the outer voltage / active and reactive power control loop is the slower one. A Lyapunov based inner (current) control is presented in this work which robustly tracks the reference current independent of the system frequency. The proposed controller is used in a grid connected single phase Photo Voltaic (PV) system and is compared with a Proportional Resonant (PR) and sliding mode controller which are generally used in AC systems. While the PR controller is tuned to operate at a particular frequency, the proposed controller performs much better in terms of tracking the reference current at any frequency. The controller is derived using the system differential equation and obtaining asymptotical stability using Lyapunov's stability criteria. © 2016 IEEE.