Ali Safaei

Bio: Ali Safaei is an academic researcher from Universiti Sains Malaysia. The author has contributed to research in topics: Control theory & Nonlinear system. The author has an hindex of 8, co-authored 22 publications receiving 293 citations. Previous affiliations of Ali Safaei include University of Tehran & McGill University.

Adaptive Model-Free Control Based on an Ultra-Local Model With Model-Free Parameter Estimations for a Generic SISO System

Abstract: In this paper, a new structure to design model-free control (MFC) based on the ultra-local model is presented for an unknown nonlinear single-input single-output dynamic system. The proposed structure includes two adaptive laws corresponding to the unknown linear and nonlinear terms. Utilizing the adaptive law for linear term, the controller gain is going to be updated online using a differential Riccati equation. Subsequently, the control policy which includes an optimal term as well as a term for compensating the system unknown dynamics is generated. Here, the two proposed adaptive laws are model-free estimation algorithms, in which the need for any regressor parameter and also the persistent excitation condition is eliminated. Finally, two simulation studies are presented to show that the proposed adaptive MFC (AMFC) policy outperforms the two well-known controllers. Moreover, the AMFC is applied on a Duffing-Holmes chaotic oscillator plant and the convincing performance of the algorithm is observed through the simulation results.

Design and Simulation of Air Cooled Battery Thermal Management System Using Thermoelectric for a Hybrid Electric Bus

Abstract: Dynamic and electric parameters of HEVs and EVs such as acceleration, regenerative braking and battery charging/discharging depend on the battery system performance. Excessive or uneven temperature rise in a module or pack of battery reduces the life cycle significantly. Therefore, improving the battery thermal management system (BTMS) is very important for reliability and cost of vehicle. The objective of this paper is to design an air cooled battery thermal management system using thermoelectric to maintains the temperature of battery in appropriate range at stressful and abuse conditions. An air flow with fans, heat sinks, fins and thermoelectrics is used for battery thermal management of hybrid electric bus to improve temperature uniformity and reduce maximum cell temperature. A battery pack consists of 12 smaller packs containing 14 porch cells with series design is selected for this study. This Li-ion battery pack specifically designed for the hybrid electric bus produced by Vehicle, Fuel and Environments Research Institute (VFERI). A detailed three-dimensional thermal model of designed battery pack has been developed using the fundamental heat transfer principles and CFD (computational fluid dynamics) analysis tools to predict the temperature distributions in cells and packs. The air flow for the battery thermal management of porch Li-ion cells is numerically analyzed using a three-dimensional CFD model. The numerical results indicate that the temperature of battery maintain below 35 °C while keeping the cell temperature difference below 5 °C during high charge/discharge rates and ambient temperature more than 40 °C. In other studies though using the air as the heat transfer medium for BTMS may be simpler, cheaper and smaller than heat transfer by liquid, but it is not recommended because it is not as effective as heat transfer by liquid. In this paper, a new method is presented that improves air cooling thermal management with help of thermoelectric. It is more effective than usual air cooling thermal management. Thermal modeling of a Li-ion battery air cooling pack suitable for hybrid electric bus using thermoelectric shows that such an approach can keep the cell temperature in the pack below the upper safety limit (35 °C) in high-rate discharge rates and under ambient temperatures higher than 40 °C.

Lyapunov-based nonlinear controller for quadrotor position and attitude tracking with GA optimization

Abstract: In this paper, a nonlinear controller using the Lyapunov stability theorem is proposed for quadrotor position and attitude tracking. The quadrotor dynamics is defined for controller design and simulations. Moreover, a simple optimization based on Genetic Algorithm is presented for determining the elements of the controller gain matrices. The simulation results show the appropriate tracking of the controlled quadrotor model. The generated model and the designed nonlinear controller could be utilized as a basis for further investigations on autonomous control of whether a single or a team of quadrotors.

Hybrid energy storage system for microgrids applications: A review

Abstract: Energy storages introduce many advantages such as balancing generation and demand, power quality improvement, smoothing the renewable resource’s intermittency, and enabling ancillary services like frequency and voltage regulation in microgrid (MG) operation. Hybrid energy storage systems (HESSs) characterized by coupling of two or more energy storage technologies are emerged as a solution to achieve the desired performance by combining the appropriate features of different technologies. A single ESS technology cannot fulfill the desired operation due to its limited capability and potency in terms of lifespan, cost, energy and power density, and dynamic response. Hence, different configurations of HESSs considering storage type, interface, control method, and the provided service have been proposed in the literature. This paper comprehensively reviews the state of the art of HESSs system for MG applications and presents a general outlook of developing HESS industry. Important aspects of HESS utilization in MGs including capacity sizing methods, power converter topologies for HESS interface, architecture, controlling, and energy management of HESS in MGs are reviewed and classified. An economic analysis along with design methodology is also included to point out the HESS from investor and distribution systems engineers view. Regarding literature review and available shortcomings, future trends of HESS in MGs are proposed.

Emergence of hybrid energy storage systems in renewable energy and transport applications – A review

Abstract: The idea of Hybrid Energy Storage System (HESS) lies on the fact that heterogeneous Energy Storage System (ESS) technologies have complementary characteristics in terms of power and energy density, life cycle, response rate, and so on. In other words, high power ESS devices possess fast response rate while in the contrary, high energy ESS devices possess slow response rate. Therefore, it may be beneficial to hybridize ESS technologies in the way that synergize functional advantages of two heterogeneous existing ESS technologies As a consequence, this hybridization provides excellent characteristics not offered by a single ESS unit. This new technology has been proposed and investigated by several researchers in the literature particularly in the fields of renewable energy and electrified transport sector. In this context and according to an extensive literature survey, this paper is to review the concept of the HESS, hybridization principles and proposed topologies, power electronics interface architectures, control and energy management strategies, and application arenas.