Half-bridge Shunt Active Power Research Articles

Hybrid automaton-fuzzy control of single phase dual buck half bridge shunt active power filter for shoot through elimination and power quality improvement

This paper addresses the problem of controlling a single phase shunt active power filter (SAPF) in presence of nonlinear loads. The considered SAPF is based on a Dual Buck Half Bridge converter (DBHB), which has the ability to eliminate the shoot-through problem arising in the conventional inverter circuit. The aim is to design a controller that is able to achieve the following three control objectives: (i) simple and indirect estimation of harmonic components, (ii) compensating for the harmonic and reactive currents generated by the nonlinear load for assuring a satisfactory power factor correction (PFC) in the grid side, (iii) regulating the DC capacitor voltage of the DBHB converter. In order to meet these control objectives, a new controller based on multi-loop structure is proposed. In the inner loop, a hybrid automaton representation of the DBHB-SAPF is used for the purpose of designing an appropriate control law so that to ensure a unity power factor. In the outer loop, a fuzzy logic controller is developed to guarantee a tight regulation of the converter DC voltage to a desired value. The effectiveness of the proposed controller is verified and validated by numerical simulation using MATLAB/Simulink environment. From the obtained results, the designed controller shows significant performance in terms of robustness and tracking compared to the standard strategy based on PI regulator.

Nonlinear adaptive control design with average performance analysis for photovoltaic system based on half bridge shunt active power filter

This paper investigates the problem of controlling a single phase shunt active power filter (SAPF) connected to two photovoltaic arrays through a half bridge inverter involving two DC link capacitors. The control aims are threefold: ensuring a satisfactory power factor correction (PFC) at the grid-power filter connection point by compensating the harmonic and reactive currents produced by the nonlinear loads; extracting a maximum active power in the output photovoltaic arrays by applying the maximum power point tracking (MPPT) block and balancing the power exchange between the photovoltaic source and the AC power grid by regulating the DC link capacitors voltages. The problem is dealt with using a cascade nonlinear adaptive controller. The inner loop is designed using sliding mode and Lyapunov stability techniques so that to ensure a unity power factor. It also includes an adaptive observer that performs online estimation of the grid state variables which are not accessible to measurements. The outer loop is mainly constituted of filtered proportional-integral (PI) regulator, that ensures a tight regulation of the photovoltaic voltage, and the incremental conductance (IC) algorithm to meet MPPT. The resulting controller performances are formally analyzed making use of averaging theory. The theoritical analysis results are confirmed by numerical simulation within MATLAB/SimPowerSystems environment.

Grid Voltage Sensorless Single-Phase Half-Bridge Active Filter and DC Bus Voltage Regulation

In this paper, a method is presented for the control of grid voltage sensorless single-phase half-bridge shunt active power filter to reduce the grid current harmonics of low-power single-phase non-linear loads. The proposed system forces the grid current to be sinusoidal without sensing and processing the grid voltage on the line. For this reason, instead of grid voltage the load current is processed by using self-tuning filter to generate reference grid current to eliminate current harmonic distortions. In order to design a low-cost system, a half-bridge voltage source converter is used to reduce driver circuits. In addition, the switching losses are also reduced by employing half-bridge voltage source converter, where only two switches are used. The imbalance voltages are also successfully eliminated on the DC-side capacitors. The performance of the proposed system is verified by using a real-time platform, and experimental results are presented to verify the effectiveness of the proposed system in this study.