Three Phase Dead-Zone Oscillator Control Under Unbalanced Load Conditions

A relatively new class of power converter controls can create self-forming AC networks without synchronous generators. These controllers have significant development and stability proofs under normal operating conditions. This paper studies one particular type, the Dead-Zone Oscillator, under unbalanced load and fault conditions. Two different implementations of this controller are used to control commercial three-phase inverters that accept either voltage or current commands. Simulations and experiment demonstrate the robustness of this controller to single phase unbalance, phase to phase faults, and open phase failures. Understanding the characteristics of this type of oscillator and applying it to unbalanced loads will help to further the process of implementing these small self-sustaining converters into larger networks with little to no adverse effects.