Rotor eccentricity and local demagnetization in permanent magnet synchronous motors (PMSMs) increases unbalanced magnetic pull and motor vibration resulting in accelerated aging of motor components. If the asymmetry in the rotor remains undetected, it can increase in severity, and increase the risk of stator-rotor contact, which causes forced outage of the motor and driven process. Detection of PMSM rotor asymmetry currently relies on off-line testing and on-line vibration/current spectrum analysis. However, they are inconvenient or cannot provide reliable detection as they are influenced by other mechanical non-idealities in the motor or load. In this paper, the feasibility of using the signals from analog Hall-effect field sensors for detecting eccentricity and local demagnetization is investigated. It is shown that Hall sensors present in machines for motion control can be used for measuring the variation in the flux inside the motor due to rotor magnetic asymmetry with minimal or no hardware modifications. 3-dimensional (3D) finite element analysis (FEA) and experimental results performed on an interior PMSM (IPMSM) show that the proposed method can provide sensitive and reliable detection of dynamic/mixed eccentricity and local PM demagnetization.

The aim of this work is to analyze and stabilize the power system when connecting an energy storage system (ESS) to replace the traditional power reserve of a power plant. Thus, it is necessary to validate and simulate the power facility protection system using a relay coordination approach. The input feasibility of the generator for the frequency regulation (FR) of the operational ESS is also validated through detailed analysis studies including power flow, short circuit and relay coordination analysis. The case scenarios for ESS installation are categorized based on its operation mode and location in the power system. These studies are carried out on the power system at the peak load condition specified for both grids. With the electrical transient analyzer program (ETAP), an analysis is performed to study the implementation of the ESS in a large, integrated power system to determine which location best fits the installation of ESS considering the load flow, short circuit and relay coordination results in each case scenario. Cost evaluation was performed for the choice of locations under study.