7,389 research outputs found
Optimal load shedding for microgrids with unlimited DGs
Recent years, increasing trends on electrical supply demand, make us to search for
the new alternative in supplying the electrical power. A study in micro grid system
with embedded Distribution Generations (DGs) to the system is rapidly increasing.
Micro grid system basically is design either operate in islanding mode or
interconnect with the main grid system. In any condition, the system must have
reliable power supply and operating at low transmission power loss. During the
emergency state such as outages of power due to electrical or mechanical faults in
the system, it is important for the system to shed any load in order to maintain the
system stability and security. In order to reduce the transmission loss, it is very
important to calculate best size of the DGs as well as to find the best positions in
locating the DG itself.. Analytical Hierarchy Process (AHP) has been applied to find
and calculate the load shedding priorities based on decision alternatives which have
been made. The main objective of this project is to optimize the load shedding in the
micro grid system with unlimited DG’s by applied optimization technique
Gravitational Search Algorithm (GSA). The technique is used to optimize the
placement and sizing of DGs, as well as to optimal the load shedding. Several load
shedding schemes have been proposed and studied in this project such as load
shedding with fixed priority index, without priority index and with dynamic priority
index. The proposed technique was tested on the IEEE 69 Test Bus Distribution
system
Switched Capacitor DC-DC Converter for Miniaturised Wearable Systems
Motivated by the demands of the integrated power system in the modern wearable electronics, this paper presents a new method of inductor-less switched-capacitor (SC) based DC-DC converter designed to produce two simultaneous boost and buck outputs by using a 4-phases logic switch mode regulation. While the existing SC converters missing their reconfigurability during needed spontaneous multi-outputs at the load ends, this work overcomes this limitation by being able to reconfigure higher gain mode at dual outputs. From an input voltage of 2.5 V, the proposed converter achieves step-up and step-down voltage conversions of 3.74 V and 1.233 V for Normal mode, and 4.872 V and 2.48 V for High mode, with the ripple variation of 20–60 mV. The proposed converter has been designed in a standard 0.35 μm CMOS technology and with conversion efficiencies up to 97–98% is in agreement with state-of-the-art SC converter designs. It produces the maximum load currents of 0.21 mA and 0.37 mA for Normal and High modes respectively. Due to the flexible gain accessibility and fast response time with only two clock cycles required for steady state outputs, this converter can be applicable for multi-function wearable devices, comprised of various integrated electronic modules
Homomorphic Data Isolation for Hardware Trojan Protection
The interest in homomorphic encryption/decryption is increasing due to its
excellent security properties and operating facilities. It allows operating on
data without revealing its content. In this work, we suggest using homomorphism
for Hardware Trojan protection. We implement two partial homomorphic designs
based on ElGamal encryption/decryption scheme. The first design is a
multiplicative homomorphic, whereas the second one is an additive homomorphic.
We implement the proposed designs on a low-cost Xilinx Spartan-6 FPGA. Area
utilization, delay, and power consumption are reported for both designs.
Furthermore, we introduce a dual-circuit design that combines the two earlier
designs using resource sharing in order to have minimum area cost. Experimental
results show that our dual-circuit design saves 35% of the logic resources
compared to a regular design without resource sharing. The saving in power
consumption is 20%, whereas the number of cycles needed remains almost the sam
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