Design of the Current and the Voltage Observers for Active-Load-Balancer (ALB) in Model Predictive Control System

In this paper, two observers for the model predictive control system of the active load balancer (ALB), are proposed. An unbalanced single-phase load in the distributed power system causes significant difficulties. An active load balancer is an efficient approach to tackle these issues. Model predictive control is one of the centralized proper control system for a power electronic converter. The main drawback of this control system is the use of numerous voltage and current sensors. Therefore, using of observers instead of sensors makes the implementation of the model predictive control system more cost effective. These two observers, estimate the load current and PCC voltage, fast and accurate as possible. This paper presents load current observer based on furrier series and voltage observer based on nonlinear Newton-Raphson method. The experimental results obtained from a 4 kW prototype ALB validate the theoretical analysis. The experimental results reveal that the proposed observers can achieve high accuracy and low costs as well as a high-quality grid side current.