This paper presents the development of a switched-reluctance machine (SRM) driven flywheel system, its charging/discharging controls and performance evaluations. By properly setting and tuning the winding commutation instant, the same SRM can be operated as a motor and a generator in the SRM-driven flywheel system with satisfactory performances. Moreover, the hysteresis current controlled PWM (HCCPWM) scheme with hard freewheeling and the commutation angle dynamic shift controller (DSC) are proposed to enhance the flywheel discharging generating performance. For interfacing the flywheel system to the DC microgrid, a half-bridge bidirectional DC/DC interface converter is developed. It is operated in buck mode under flywheel charging and in boost mode under flywheel discharging. The dynamic modeling and controller design are conducted to yield well-regulated DC output voltage under varying flywheel driven switched-reluctance generator (SRG) speed. Finally, the measured results are given to verify the performances of the established flywheel and its interconnected operation to a wind SRG based DC microgrid.

This paper presents the development and control of an electric vehicle (EV) synchronous reluctance motor (SynRM) drive. A bilateral DC/DC converter is used as an interface between the battery and the motor drive. The boostable and well-regulated DC-link voltage with robust regulation control can enhance the motor driving performance in the constant torque region. And the regenerative braking energy can be successfully recovered to the battery. In SynRM drive, the robust current PWM switching control considering inherent slotting effects and robust speed model reference control are made. Moreover, an adaptive commutation scheme (ACS) is developed to automatically set the commutation instant for achieving the motor total loss minimization. The dynamic and static driving characteristics of the established EV SynRM drive in various conditions are verified experimentally.

This paper presents an electric scooter with grid-to-vehicle/vehicle-to-home (V2H)/vehicle-to-grid (V2G) and energy harvesting functions. First, the bilateral dc/dc converter-fed scooter dc motor drive is established. Good driving characteristics are achieved via proper control. In an idle case, the motor drive can be arranged to perform the V2H and V2G discharging operations. A front-end dc/dc converter is developed using the motor-drive-embedded components to establish the boosted and well-regulated dc-link voltage from battery. Then, an H-bridge single-phase inverter is established to yield the ac 110-V/60-Hz source for home appliances or emergency power use. Good output sine-wave voltage waveforms are yielded by the designed robust and proportional-plus-resonant controllers. Moreover, the V2G operation is also applicable. The battery can send power to the utility grid. In addition, a synchronous rectifier-based buck dc/dc converter is designed to establish a universal serial bus with 5-V dc for charging various peripheral devices. Conversely in charging mode, an H-bridge boost switch-mode-rectifier-based charger is formed using the same schematics. Good charging characteristics and line drawn power quality are obtained. As to the photovoltaic (PV) energy harvesting scheme, the energies of roof PV or possible dc sources can be harvested to make the battery auxiliary charging.

The term “geopolymer” was introduced by Davidovits in the 1970s. The prefix “geo” was selected to symbolize the constitutive relationship of the binders to geological materials, natural stone and/or minerals. Geopolymer is mineral polymers of inorganic polymer glasses with structure resembling natural zeolitic materials. Previously, geopolymer formation used source materials such as clay (e.g. kaolin and calcined kaolin) or industrial by-product (e.g. slag and fly ash). The precursor material plays an important role in the formation of geopolymer. The source material provides silicon (Si) and aluminum (Al) for reaction by an alkali activator solution. The Si and Al contents in the source materials dissolve in the alkaline activator solution and then polymerize to form a polymeric Si-O-Al-O framework which becomes the binder. Geopolymeric materials are attractive because of their excellent mechanical properties; durability and thermal stability can also be achieved. Owing to their low calcium content, they are more resistant to acid attack than materials based on Portland cement. In addition, they are of great interest because of the reduced energy requirement for their manufacture and the higher sustainability. Recently the search for alternative low cost and easily available materials led among others to Clay. Clay generally consists of a mixture of different clay minerals and associated minerals, which are strongly affected by the nature of the parent rocks. These materials are extensively distributed over the surface of the world and may show certain reactivity after a thermal activation process shows a great potential to be utilized in geopolymer technology. This article presents the potential of different types of clay as the source materials for geopolymerization reaction in terms of morphological properties. Moreover, the mechanical and microstructural properties of geopolymer made with various kinds of clay and its potential application are also presented.

This article presents a battery/supercapacitor (SC) powered electric vehicle (EV) switched-reluctance motor (SRM) drive and its microgrid incorporated operation control. The battery and the SC are connected to the motor drive dc-link via an H-bridge converter and a one-leg boost–buck converter, respectively. The varied dc-link voltage can be set lower and higher than the battery voltage to yield the improved EV driving performance over a wide speed range. Through the proposed current sharing control approach for the battery and SC, the battery can possess smooth discharging current characteristics. The SC is arranged to be charged by the battery during constant speed driving duration to preserve sufficient energy. In the proposed EV SRM drive current control scheme, the feedback controller is augmented with an observed back electromotive force (EMF) feedforward controller and a robust current tracking error cancellation controller. More importantly, for EV, the commutation shifting and the voltage boosting are applied to reduce the effects of back EMF on the current control under higher speeds and/or heavier loads. The regenerative braking is successfully conducted. Similarly, the speed dynamic control is also enhanced by adding robust control. As to the microgrid incorporated operation, the EV SRM drive can perform the microgrid-to-vehicle (M2V) and vehicle-to-microgrid (V2M) operations to dc microgrid. The required schematics are formed using the embedded converters in the EV drive or the microgrid. Successful operations are verified experimentally.

In this paper, an improved winding current control scheme for switched-reluctance motor drive is developed and evaluated. The current feedback controller (CFBC) is augmented with an observed back electromotive force (EMF) current feedforward controller (CFFC) and a current tracking error adapted dynamic commutation shift controller (DCSC). In the proposed DCSC, the rising winding current tracking errors of all phases are extracted, synthesized, and processed to generate the suitable advanced commutation shift angle. The effects of motor back EMF and nonlinear winding inductance can be reduced to yield improved winding current tracking waveforms under a wide operation range. The gradual improvements in current responses and efficiencies by augmenting the CFBC with the CFFC and then the DCSC are verified experimentally. Then, the robust speed control scheme is properly designed to achieve good acceleration/deceleration, reversible running, and dynamic characteristics.