Super-capacitor energy storage system to recuperate regenerative braking energy in elevator operation of high buildings

<span>In operating phases of elevators, accelerating, braking modes occur frequently, so braking energy recuperation of elevators has contributed considerably to decrease the total electric energy consumption for operating elevators in multi-floor buildings. In this paper, the supercapacitor energy storage system is used to recover regenerative braking energy of elevators when they operate down full-load and up no-load, reducing fluctuation of voltage on DC bus as well. Therefore, super-capacitor energy storage system (SCESS) will be parallel with line utility to recuperate regenerative braking energy in braking phase and support energy for acceleration phase. The surplus energy will be stored in the supercapacitors thanks to a DC-DC converter capable of exchanging energy bidirectionally in buck/boost modes, and designing control strategy including two control loops. Inner loop-current loop: controlling charge/discharge process of supercapacitors by current iL complying with operation characteristic of elevator; Outer loop-voltage loop: managing UDC-link at a fixed value. Simulation results with elevator system of the ten-floor building, Hanoi, Vietnam installed SCESS have been verified on MATLAB Simulink, SimPowerSystem with saving energy level about 30%.</span>

PV-Supercapacitor Cascaded Topology for Primary Frequency Responses and Dynamic Inertia Emulation

Owing to rapid increase in PV penetration without inherent inertia, there has been an unremitting deterioration of the effective inertia of the existing power systems. This may pose a serious threat to the stability of power systems during disturbances if not taken care of. Hence, the problem of how to emulate Synthetic Inertia (SI) in PV Systems (PVS) to retain their frequency stability demands attention. Super Capacitor (SC)-based storage become an attractive option over the other energy storage types because of its high-power density, burst power handling capability, faster response and longer life cycle. Considering this, the authors here propose a novel PV-SC Cascaded Topology (PSCT) as a cost-effective approach to emulate SI by integrating a low voltage SC to a high voltage grid-connected PVS. The proposed PSCT helps in operating the SC as a voltage source rather than a current source. Thus, it eliminates the high gain requirements of the SC interfacing converters. The aim is to target two main frequency response services, i.e., Primary Frequency Response (PFR) and Synthetic Inertial Response (SIR), using a novel common control scheme, but without affecting any other energy intensive services. The authors introduced a Droop-Inspired (DI) method with an adjustable inertia constant to emulate dynamic inertia so that a wider range of Rate of Change of Frequency (RoCoF) values can be serviced with a limited storage. A very streamlined analysis was also carried out for sizing of the SC stage based on a simple Three-Point Linearization (TPL) technique and DI technique with a limited knowledge of the disturbance parameters. The whole system was initially validated in a MATLAB Simulink environment and later confirmed with the OPAL-RT Real-Time Simulator. The investigated response was subject to variation in terms of control parameters, changes in solar irradiance, grid frequency variation, etc.

Designing & Analysis of Supercapacitor Hybrid Battery System with Regenerative Braking

This work implements the help of a super capacitor hybridized with a battery pack to power a motor to work an electric bike. The supercapacitor of specification is built in combination with the battery pack to work in pair at instances where more load in needed. For example in situations like accelerating, decelerating, and climbing a slope. The supercapacitor is recharged while in motion using two different technologies: 1. Regenerative Braking and 2. Generator incorporated into wheel hub. Regenerative braking is an energy recovery mechanism that slows down a moving vehicle or object by converting its kinetic energy into a form that can be either used immediately or stored until needed. In this mechanism, the electric traction motor uses the vehicle's momentum to recover energy that would otherwise be lost to the brake discs as heat. This contrasts with conventional braking systems, where the excess kinetic energy is converted to unwanted and wasted heat due to friction in the brakes, or with dynamic brakes, where the energy is recovered by using electric motors as generators but is immediately dissipated as heat in resistors. In addition to improving the overall efficiency of the vehicle, regeneration can significantly extend the life of the braking system as the mechanical parts will not wear out very quickly. The system uses Faradays Law of Electromagnetic Induction to induce an EMF and generate voltage by passing a current carrying conductor through a rotating magnetic field. Using this implementation, it has been noted that the battery life has been increased significantly and the total range of the bike has also increased considerably. Keywords: Batteries, Battery pack, Supercapacitor, Hybrid power system, Dynamo mechanism

Influence of ZnO nanoadditives on the structural characteristics and dielectric properties of PVA

In this study, different percentages of semiconducting zinc oxide nanoparticles (ZnONPs) are mixed with polyvinyl alcohol (PVA) to create flexible ZnO/PVA polymer nanocomposite films. The characteristics of the prepared films are investigated using differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. The XRD pattern shows that the ZnO/PVA composite films were successfully synthesized; while the SEM images show that the ZnONPs are homogeneously dispersed in the PVA polymer chain. Moreover, the DSC indicates an improvement in the thermal stability behavior with increased of ZnONPs concentration. The electrical conductivity, dielectric properties, electric modulus behavior, and the energy density efficiency of the pristine PVA and ZnO/PVA composite films are determined using an LCR meter in the frequency range 102–106 Hz. The dielectric constant of the composite film increased from 0.185 for pristine PVA to 1.389 for 9%ZnO/PVA, and the conductivity is improved from [Formula: see text] S/cm to [Formula: see text] S/cm. This work would open the road for utilizing ZnO/PVA flexible nanocomposite films for wide range of applications such as batteries, super-capacitor and energy storage devices.