The three phase inverter for Optimal load & voltage control Using THD & UPS

Abstract

This paper proposes a simple optimal voltage control method for three-phase uninterruptible-power-supply systems. The proposed voltage controller is composed of a feedback control term and a compensating control term. The former term is designed to make the system errors converge to zero, whereas the latter term is applied to compensate for the system uncertainties. Moreover, the optimal load current observer is utilized to optimize system cost and reliability. Concretely, the closed-loop stability of an observer-predicated optimal voltage control law is mathematically proven by exhibiting that the whole states of the augmented observer-predicated control system errors exponentially converge to zero. Unlike anterior algorithms, the proposed method can make a tradeoff between control input magnitude and tracking error by simply culling opportune performance indexes. The efficacy of the proposed controller is validated through simulations on MATLAB/Simu link and experiments on a prototype 600-VA testbed with a TMS320LF28335 DSP. Determinately, the comparative results for the proposed scheme and the conventional feedback linearization control scheme are presented to demonstrate that the proposed algorithm achieves an excellent performance such as expeditious transient replication, minute steady-state error, and low total harmonic distortion under load step change, unbalanced load, and nonlinear load with the parameter variations.