Mahmoud Alahmad

Modeling Discharge Behavior of Multicell Battery

Multicell battery has been widely used in various electrical and electronics devices. To achieve the optimal multicell battery design, accurately modeling battery discharge behavior of multicell battery is crucial. However, modeling discharge behavior of multicell battery is very challenging due to the nonlinear battery effects, nonuniform cell quality, and various cell connections. In this paper, we develop a circuit-based multicell battery model to accurately model the multicell battery discharge behavior in terms of available capacity, output voltage, and internal resistance with consideration of nonlinear battery effect and nonuniform cell quality. It also characterizes the cell discharge current distribution of cell strings in parallel connection. The proposed multicell battery model has been validated by extensive simulation and experimental results under various load conditions.

A Comparative Study of Three Feedback Devices for Residential Real-Time Energy Monitoring

Residential energy consumption accounts for 21% of the total electricity use in the United States. Unfortunately, research indicates that almost 41% of this power is wasted. Changing the way that consumers use energy may be important in reducing home energy consumption. This paper looks at whether the implementation of certain real-time energy monitors has an impact on the residential rate of energy consumption in a metropolitan area with relatively low electricity rates. In the following case study, 151 Omaha residences were equipped with two variants of the Aztech In-Home Display (Aztech) as well as the Blue Line Power Cost Monitor (PCM) real-time energy monitors for a period of 16 months. The results of the data, 30 days after installation, revealed a statistically insignificant reduction of 12% in mean electrical consumption in houses equipped with a PCM and no reduction in mean consumption in homes using either variants of the Aztech device when compared to a randomly selected control sample. However, they proved effective in the short term if utilized by utilities for mass distribution to foster awareness among participating residents of their own patterns of residential electricity consumption and on the environmental impacts of energy saving.

An enhanced circuit-based model for single-cell battery

Battery performance prediction is crucial for battery-aware power management, battery maintenance, and multi-cell battery design. However, the existing battery models cannot capture the circuit characteristics and nonlinear battery effects, especially recovery effect. This paper aims to fill this gap by developing an enhanced circuit-based model for single-cell battery. The proposed model is validated by comparing simulation results with experimental data collected through battery testbed. The comparison shows that the proposed model can accurately characterize and predict the single-cell battery performance with considerations of various nonlinear battery effects under both constant and variable loads.

A Novel Design of Adaptive Reconfigurable Multicell Battery for Power-Aware Embedded Networked Sensing Systems

Battery-powered embedded networked sensing systems become more and more pervasive with the fast-paced deployment of various remote sensing applications. How to prolong the battery operating time is one of the most challenging areas in the design and development of these sensing systems due to the fact that the battery operation is much more dynamic and complex than considered, which is derived from its application and its internal structure (multiple hardwired series/parallel cells) to produce a specific voltage and capacity. Current research on prolonging the battery operating time is mainly focusing on the low-power hardware and energy-efficient network protocol designs, and simply treats the battery as a passive two-terminal energy source. In this paper, we will propose a novel adaptive, proactive, and reconfigurable multicell battery design for supporting power-aware hardware and energy-efficient network protocols for embedded networked systems, which provides a whole new perspective to look at the energy problems of battery- powered embedded networked sensing systems. A theoretical modeling of the proposed design is provided, and simulation results show that the proposed design can significantly enhance the energy performance, especially for low voltage and low discharge current scenarios.

Evaluation and Analysis of a New Solid-State Rechargeable Microscale Lithium Battery

Battery characteristics and behavior under a wide range of tests are an integral part in the development of specific properties and performance for a newly developed battery. The results are used to classify the battery working conditions and to set the parameters of its power management system and control algorithm to incorporate innovative features to manage and improve the batterys life cycle and operation. This paper will present experimental evaluation and analysis of results conducted on a new solid-state rechargeable microscale lithium batteries (microbatteries) developed by Jet Propulsion Laboratory for aerospace applications. Analysis includes overcharge, undercharge, faulty conditions, and application of several charge and discharge methods during normal mode of operation. To take advantage of the voltage and capacity yield, the microbatteries are analyzed individually while connected in parallel, series, or parallel-series configurations. The results are used to develop a dynamic battery power management system. A description of the system and the results obtained from a prototype circuit, designed to validate its operation, will also be discussed.

Adaptive photovoltaic system

This paper discussed a new photovoltaic (PV) system topology that uses PV energy in efficient way in order to improve system power output during different operating conditions. The proposed topology provides flexible connection between PV modules to achieve different configurations of PV array. A new switching matrix has been developed to achieve the required configurations. Preliminary simulations provide promising results for an adaptive PV array. Comparison between traditional PV system configurations and adaptive configuration is considered. A significant improvement in power curves is achieved by the proposed topology.

Dynamic reconfigurable multi-cell battery: A novel approach to improve battery performance

Many electronic systems such as robotics, battery-powered electric vehicles, and mobile computing devices are powered by multi-cell battery with limited energy capacity. Therefore, maximizing the battery performance such as operating time, available capacity, and lifetime is one of the major battery design challenges. Traditional approaches such as dynamic power management to maximize the battery discharge performance have treated multi-cell battery as a pure passive component with a fixed configuration. Thus, the multi-cell battery performance is determined by the weakest battery cell, leading to a low utilization of battery energy. In this paper, we propose a novel multi-cell battery design to dynamically reconfigure the cell topology of a multi-cell battery, which also interacts with the power management module of a battery-powered system to maximize the battery discharge performance. Then, the dynamic reconfiguration problem of the multi-cell battery is formulated as a Lagrangian Relaxation problem and solved by dynamic programming. Both simulation and experimental results show that the proposed design can significantly enhance the multi-cell battery operating time and useable capacity. Moreover, the proposed design can automatically exclude the failure or malfunction cells through reconfiguration, which can greatly improve the multi-cell battery safety.

Estimation of induction motor equivalent circuit parameters from nameplate data

The induction motor equivalent circuit parameters are required for many performance and planning studies involving induction motors. These parameters are typically calculated from standardized motor performance tests, such as the no load, full load, and locked rotor tests. However, standardized test data is not typically available to the end user. Alternatively, the equivalent circuit parameters may be estimated based on published performance data for the motor. This paper presents an iterative method for estimating the induction motor equivalent circuit parameters using only the motor nameplate data.

Lifetime Optimization for Wireless Sensor Networks Using the Nonlinear Battery Current Effect

One of the design challenges of wireless sensor networks is the tradeoff between network operation time and network coverage. Recent studies reveal that the useable battery capacity drops faster at a higher discharge current in a nonlinear fashion. To take advantage of this battery current effect, in this paper we explore a new sensor node deployment scheme to prolong the entire sensor network lifetime as well as each individual sensor node. The key idea of the proposed scheme is to assign a sensor node having higher traffic load to adopt lower transmission power level. In this way, batteries of all nodes in a given area are discharged at the same current, thus they are depleted at the same time. Extensive simulations have conducted to evaluate the performance of the proposed sensor node deployment scheme. Compared with peer work on heterogeneous deployment, the useable battery capacity by using the proposed scheme can be improved by 26.67%, and the operating time per sensor node can be enhanced by 20.95%. Furthermore, the proposed deployment scheme can reduce the number of sensor nodes required to cover the given area, leading to a significant reduction of deployment cost.

On the Discourse of Energy as Material: Future Feedback Technologies and Directions for Experiencing Energy

Engineers are increasingly considering the social dimensions of energy use in the design of energy conservation technologies. This has led to design informed by ethnographic and theoretical inquiry on everyday energy practices and user-technology interactions that will in turn shape future practices and interactions. This paper contributes to the small but growing literature on real-time residential energy feedback displays that more closely examines how users experience such technologies. Survey responses from participants involved in a large-scale residential energy feedback monitoring case study are analyzed and contextualized into a set of positive and negative user “experiences.” The qualitative data derived from these responses add new insight on the social variables of user interaction with real-time feedback monitors that are of use to both the study of energy feedback monitoring and the design of future smart communities. Finally, an example is given of how these participant “experiences” are being put to the test in the design of a new energy feedback technology with implications for future ways of conceptualizing energy.