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This work investigates the effects of shifting the permanent magnet axis with respect to the reluctance axis on the performance of Permanent Magnet AC (PMAC) machines in applications with a wide constant power speed range (CPSR), such as traction and spindle drives. A simplified optimization design study is conducted to study the effects of shifting the magnet axis with respect to the reluctance axis...
Demand response is an important resource that can significantly increase the efficiency of the future power systems. It is a key component of smart grids that can bring a lot of benefits to power system operators and customers. This work assesses potential impacts of demand response on some major attributes of the distribution system such as the network losses, voltage profiles, and maximum power...
This paper describes the power control strategies of a fuzzy controlled grid connected hybrid photovoltaic and proton exchange membrane fuel cell distributed generation system with battery as energy storage device. The primary source of energy for the hybrid distributed generation system is from photovoltaic cell and proton exchange membrane fuel cell and the battery acts as a complementary source...
This paper proposed an enhanced real-time state estimation using Iterative Extended Kaiman Filtering (IEKF). The IEKF estimated state variables based on past state variables. Largest Normalized Residual Test (LNRT) was integrated with IEKF for bad data detection. A comparison with the conventional Weighted Least Squares (WLS) was also investigated using the IEEE 14 bus test system simulated in MATLAB...
An important challenge in the design of air-core superconducting machines is the containment of the magnetic fields within the electric machine. Current solutions result in large reductions of the high power density achievable through the use of superconducting windings. To address this challenge, an actively shielded electromagnet design, an approach commonly used in MRI magnet designs, is considered...
Nigeria has a population of over 160 million, and just over 50% have electricity access. Many initiatives promote solar energy development to mitigate Nigeria's power challenges. This work shows an economic valuation of the solar photovoltaic (PV) potential in Nigeria. Assuming a 100 megawatts (MW) capacity upgrade, this paper compares distributed residential-scale and centralized utility-scale PV...
This paper presents the parameter estimation problem for single-phase induction motors (SPIMs) using start-up transient voltage and current measurements available at the motor terminals. This non-instrusive estimation approach relies on a dynamic state-space representation for modeling the SPIM transients, which is augmented by the parameters of interest assumed to be constant quantities during start-up...
Poorly damped or unstable mode of inter-area oscillations is undesirable as they result in inefficient operation of the power systems. Without proper remedial actions, these oscillations can result in power systems separation or major blackouts. Adequate damping of these oscillations is a pre-requisite for secure operation of power systems. An available solution to damp out these inter-area oscillations...
Phasor measurement units (PMUs) installed in the power grid are currently positioned mainly on the transmission system or in substations. A PMU creating real-time synchrophasor data from the consumer voltage level, called μPMUs, could provide new insight into modern power systems. These units can be created more cheaply, an order of magnitude less, than current commercial PMUs. For this reason, many...
Discussion of the future of the Smart Grid brings with it issues regarding the current level of distribution system visibility. Phasor Measurement Units (PMU) have been proliferating throughout the electric power grid in order to support future distribution system analysis. One type of PMU is the Frequency Disturbance Recorder (FDR); it records voltage magnitude, frequency, and phase angle at the...
This paper proposes a new Maximum Power Point Tracker (MPPT) topology for a single phase, grid-connected PV system considering the sudden changes in environmental conditions. The MPPT takes into account the nonlinearity of photovoltaic (PV) array, the oscillation of PV voltage around the MPP, and the inverter filter design. The MPPT is designed so that current reference is computed directly from the...
The desire to reduce model-dependency has driven measurement-based modal identification methods, as an alternative to analyzing linearized system models. One such measurement-based method is Dynamic Mode Decomposition (DMD), which has recently appeared in literature. Using this relatively fast DMD algorithm, this paper presents an interactive modal-identification tool for spatio-temporal analysis...
This work introduces a new approach using high frequency (HF) isolation transformers with a series resonant power transfer mechanism for interfacing next-generation offshore wind turbine generators (WTGs) to medium voltage DC (MVDC) collection grids, a necessity for the continued development of offshore wind resources as farms are sited further out to sea. Analysis of the proposed approach is provided,...
This paper proposes a standalone distributed photovoltaic system which includes two independently controlled solar power sources, a battery storage and a resistive load. Each of the PV panels consist of cascaded DC-DC boost converters controlled through two independent sliding mode controllers. The design and simulation of the supervisory controller are also discussed. First, maximum power point tracking...
This paper presents a fault-tolerant technique for multilevel Cascaded H-Bridge (CHB) inverters. A faulty power switch in high power converters can lead to expensive downtime, loss of productivity, and increased costs. In the event of a fault, the defective cell is bypassed and a backup H-Bridge cell is replaced to generate balanced line-to-line voltages. Using the remaining cells, CHB inverter will...
This paper presents an optimal charging method for plug-in electric vehicles (PEVs) with single-phase on-board chargers that are connected to a large apartment buildings. The objective of the optimal charging is to minimize the total line power loss in a distribution network while taking into account the distribution line capacity and the three-phase building load imbalance. Using the inherent capability...
This paper presents an optimization based technique to design the proportional and integral coefficients of the adaptive mechanism of a Model Reference Adaptive System (MRAS) based estimator in a Permanent Magnet Synchronous Motor (PMSM) drive system. In this paper, first the MRAS based drive system is modeled linearly. Then the idea of the paper is explained based on the linear model. Finally, the...
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