Azhar Ul-Haq

Smart charging infrastructure for electric vehicles

In view of electro-mobility, charging infrastructure for electric vehicles needs to be deployed optimally to keep them powered up. This paper aims at developing a framework with novel aspects for deployment of charging infrastructure for EVs. This paper discusses the pros and cons of various proposed techniques for EVs charging infrastructure and also compares different available technologies in the current scenario. Moreover, various charging characteristics of battery electric vehicles and different charging methodologies and standards are investigated for practical realization of the facility infrastructure framework. Then, this paper presents a novel smart bidirectional interface equipped with multilevel cascaded power converter with embedded strategies of reverse energy flow management supporting enhanced expansion of renewable energy integration in order to keep stress on the power grid to a minimum. Moreover this paper proposes appropriate wireless communication technologies for deploying effective communication bridge among all nodes of the network in order to make the infrastructure smart. MatLab simulations are performed for provision of quality of service vs. operating cost of the charging facility. The simulation results show that the proposed technique prevails over the other available technologies in terms of cost and QoS. Future research work is also mentioned in this paper for the complete development of the proposed framework of smart charging station.

On flatness-based control for series-connected VSC for voltage dip mitigation

The grid connected series converter is a custom power device that is mainly used for mitigation of voltage sags. In this paper a novel direct flatness-based control (FBC) in cascade configuration, constituted by an outer voltage and an inner current controller, is presented. It can absorb and inject active and reactive power into the grid. Simulation model includes the practical limitation of voltage source converter output voltage and computational delay. Then, the simulations results for the FBC under balanced voltage dips are presented and compared with traditional proportional integral controller. Finally, the sensitivity analysis of the FBC for grid frequency, phase angle jump and inaccurate knowledge of system parameters are presented.

FPGA based one-cycle control of multilevel cascaded H-Bridge inverter

This paper presents One-Cycle Control (OCC) of nine-level cascaded H-bridge inverter implemented in Altera FPGA Cyclone-III. The OCC, being a nonlinear technique, overcomes some problems related to nonlinear nature of switching power converters, thus allowing fast dynamic response and robustness to power source and load perturbations. An optimum power sharing strategy, among different modules of the multilevel inverter, is also presented that equalizes power sharing at the each H-bridge. After a description of the system some simulation results obtained in ModelSim are presented showing the effectiveness of the OCC which follows the reference signal, sinusoidal, in a concrete manner with the capability of regaining steady-state in just one switching cycle. There is neither dynamic error or steady-state error between the reference signal and the switched output.

Computational time quantification of the single diode PV models

A range of photovoltaic (PV) models of different accuracy and complexity are available in the literature. The proper PV model for a particular study is selected based on the desired accuracy and computational time. Although the accuracy of the single diode models is well studied, there is still no available quantification for the computational time needed to simulate a certain PV model. This paper studies the computational time of the single diode models and derives empirical formulas quantifying the computational time needed to model PV arrays. This will enable users to calculate the expected simulation time for running their simulation. The results of this paper will help PV researchers and designers select the suitable PV model for simulating a specific PV system.

Impact of electric vehicles on voltage profile and harmonics in a distribution network

This paper focuses on potential power quality impact of electric vehicles in terms of voltage profile and harmonic contamination in a low voltage CIGRE benchmark distribution system. Voltage drop and harmonic distortion have been amongst the main power quality concerns in view of likelihood of large-scale penetration of electric vehicles in transportation system. Simulations are carried out to quantify the power quality index at different electric vehicle penetration levels while considering three distinct charging strategies. The power quality indexes are found much beyond their allowed limits at only 45% EV penetration.

Energy efficient and low complex wireless communication

Network coding designs over GF(q) spans an extensive range of research directions covering a wide range of applications. Galois field used for network coding should be a function of the total number of nodes in the networks. Thus, the larger the number of sources and relays the larger the Galois field, while keeping the same diversity order in relay-aided transmission. Furthermore, the modulation order and the Galois field are the same and this solution introduces a constraint on achievable rate and decoding complexity as network code and modulation cannot be chosen independently. In order to overcome this important limitation, in this paper we propose a splitting based approach where network coding and modulation are not necessarily the same. Our results show that if the modulation order is smaller than the Galois field; we are still able to achieve the same diversity order with lower decoding complexity.

On the Achievable Diversity-Complexity Tradeoffs of Joint Network-Channel Coded Cooperative Communication

In this paper, a novel mathematical framework for the analysis and optimization of Joint-Network -- Channel Coded Diversity (JNCCD) protocol is presented. The analysis is applicable to relay -- aided protocols based on the error propagation model, which rely on appropriately designed diversity combining demodulators at the destination. Wireless networks with an arbitrary number of sources and relays are considered. Arbitrary multilevel modulation schemes and network codes constructed over Galois Field (GF) are analyzed and JNCCD protocols are investigated. Our results show that if the modulation order is smaller than the Galois field, we are still able to achieve the higher diversity order with lower decoding complexity.