A new switched-capacitor boost-multilevel inverter using partial charging

In this brief, a new switched-capacitor-boost-multilevel (SCBM) inverter is proposed and implemented. This inverter possesses the distinct features of both voltage boost up and near-sinusoidal staircase output voltage. The key is to utilize partial charging in such a way that multiple voltage steps per capacitor can be realized, hence significantly reducing the number of capacitors for a given number of levels. Based on using only two capacitors, a 13-level SCBM inverter is designed and analyzed, with emphasis on assessing its total harmonic distortion. Both simulation and experimental results are given to confirm the theoretical analysis. © 2007 IEEE.published_or_final_versio

A novel zero-current soft-switching converter for switched reluctance motor drives

A new zero-current-transition (ZCT) power converter for switched reluctance motor drive applications is presented. The proposed ZCT power converter possesses the definite advantages that both the main and auxiliary switches are operating with zero-current switching (ZCS), as well as minimum current and voltage stresses. It has a simple circuit topology, minimum component count and low cost. The ZCT technique can significantly reduce the switch-on or -off losses by forcing the current to zero prior to its turn-on or turn-off. The proposed power converter is especially advantageous for switched reluctance motor (SRM) drives demanding efficient regenerative braking, such as electric vehicle application.published_or_final_versio

Design and implementation of neural network based capacity indicator for lithium-ion battery

Usable remnant energy of a rechargeable battery is proportional to its state of charge, but the values of these two parameters are not exactly the same. A circuit based on neural network is developed for available capacity estimation of lithium-ion battery. To ensure the network consisting of optimal numbers of hidden layers and neurons, intensive experiments have been performed and various training algorithms have been evaluated. The experimental results reveal that the circuit is able to estimate the available capacity of a battery with arbitrary discharging profiles as well as continuous constant current discharging profiles. This paper presents the roadmap for the design and the practical constraints for hardware implementation of a neural network based lithium-ion battery capacity indicator.link_to_OA_fulltex

Effective charging method for ultracapacitors

One of the advantages of ultracapacitors is its high power capability, which is applicable for high rate of charging and discharging operation like motor starting and regenerative braking of an electric vehicle. This paper presents a new charging method for ultracapacitors. Comparing with batteries, ultracapacitor can accept a wide range of charging current and can be fully charged within a few minutes. Common chargers for ultracapacitors are usually equipped with current transducers and closed loop circuitry for current control, which are expensive and complicated. The proposed circuit consists of a minimum number of components. It does not require any current transducer or dedicated voltage/current control circuitry. A simple open-loop control system is applicable for the whole charging stage. It is free of stability problem and protects itself from being overloaded by ultracapacitor with zero initial charge. This paper presents the design and operation of the hardware circuit. Both simulation and experimental results are included.link_to_OA_fulltex

A new switched-capacitor inverter for electric vehicles

This paper presents a new switched-capacitor inverter circuit based on partial charging. A number of switched-capacitor inverter circuits have been developed, but most of them are based on switching of fully charged capacitors in specific sequence to generate staircase ac voltage. In order to reduce the output distortion, the numbers of capacitors and switches should be increased. However, complexity of the circuits will also be increased dramatically. Moreover, the number of capacitors of conventional switched-capacitor inverters should be limited, otherwise, the peak output voltage could exceed stipulated limit. The new switched-capacitor circuit operates in such a manner that the capacitors will be switched to generate an ac output while they are partially charged. Each capacitor can provide multilevel voltages because the state of charge is varied. Theoretically, ac voltage with unlimited steps can be created with a few of capacitors. Experiments and simulations of a thirteen-level inverter that consists of only two capacitors are included in this paper.link_to_OA_fulltex

Sentence types and complexity of spontaneous discourse productions by Cantonese-speakers with traumatic brain injury– a preliminary report

202203 bcfcNot applicableOthersDGRF of CBS, PolyUEarly release12 month