Design and Performance Analysis of Three-Phase Solar PV Integrated UPQC

Abstract—

This paper deals with the design and performance analysis of a three-phase single stage solar photovoltaic integrated unified power quality conditioner (PV-UPQC). The PV-UPQC consists of a shunt and series connected voltage compensators connected back to back with common DC-link.The shunt compensator performs the dual function of extracting power from PV array apart from compensating for load current harmonics. An improved synchronous reference frame control based on moving average filter is used for extraction of load active current component for improved performance of the PVUPQC. The series compensator compensates for the grid side power quality problems such as grid voltage sags/swells. The compensator injects voltage in-phase/out of phase with point of common coupling (PCC) voltage during sag and swell conditions respectively. The proposed system combines both the benefits of clean energy generation along with improving power quality. The steady state and dynamic performance of the system are evaluated by simulating in Matlab-Simulink under a nonlinear load. The system performance is then verified using a scaled down laboratory prototype under a number of disturbances such as load unbalancing, PCC voltage sags/swells and irradiation variation.

FAULT DETECTION OF BRUSHLESS PERMANENT MAGNET MACHINE DRIVES

Abstract--

In the last two decades, permanent magnet synchronous machines (PMSMs) have attracted much interest and have been largely investigated for modern industries and special applications. Although the use of the permanent magnet for the magnetic field creation brings a number of merits, the low fault tolerance capability is an inherent weak point for the PMSMs. A few short-circuit turns lead to significant increase in the faulting winding current and excessive heat generation. This may further propagate and eventually cause a catastrophic failure. Based on the above reason, fault detection in PMSMs has become crucially important and necessary, especially for applications demanding high security and reliability. This forms the basic motivation of this research work.

In this thesis, the modelling of PMSM with inter-turn short-circuit faults is presented first. The developed PMSM model can represent the motor operation under normal and short-circuit fault conditions. A winding fault detection technique is addressed by applying the sequence component theory. To eliminate the influence of disturbances on fault detection, a fuzzy logic based approach is considered in this work. The simulation results have shown that the proposed fault detection approach is capable of diagnosing the faulting phase accurately and quickly under both load and speed fluctuations.