Majlesi Journal of Energy Management
Volume:1 Issue: 3, Sep 2012

This paper studies an output voltage regulation for Negative Output Elementary Super Lift Luo Converter (NOESLLC) operated in Continuous Conduction Mode (CCM) using Proportional-Integral (PI) controller parameters setting. The NOESLLC performs the voltage conversion from positive DC source voltage to negative DC load voltage. In order to improve dynamic performance of NOESLLC for both static and dynamic specifications, we propose a PI controller. The parameters value of the PI controller is computed based on the Ziegler-Nichols method – 1 tuning design procedure. The PI controller is designed by using state-space average modeling of NOESLLC. The simulation of NOESLLC with its control model is implemented in MatLab/Simulink. The static and dynamic performances of the system are tested at various regions. A simulation results validate the effect of the parameters value of PI controller on the static and dynamic performances of the NOESLLC, which is applicable for common DC-DC conversion purpose, computer power supplies, communication equipments and medical equipments.

Widespread applications of power electronic-based loads continue to increase concerns over harmonic distortion. The Current harmonics produced by non-linear loads result in voltage distortion and leads to various power quality problems. Moreover these non-linear loads are not fixed and change randomly. However classic filters may not have satisfactory performance in such fast varying conditions. This project presents a fuzzy and nuero controlled shunt active power filter used to compensate for harmonic distortion in three-phase four-wire systems. The shunt active filter employs a simple method for the calculation of the reference compensation current based on Fast Fourier Transform. This presented filter is able to operate in both balanced and unbalanced load and also for variable load conditions. A fuzzy and nuero based current controller strategy is used to regulate the filter current and hence ensure harmonic free supply current. The validity of the approach presented in harmonic mitigation is verified via simulation results of the proposed test system under different loading conditions.

The short circuit withstand test is the only test which is not performed in the manufacturers test laboratory. There is a need for a high test field power, especially for large units with ratings of 100MVA and above. The tests can only be performed at a few powerful test stations, such as those operated in KEMA (Netherlands), EDF (France), CESI (Italy) or IREQ (Canada). Short circuit tests are expensive. Not only is the cost of the test itself high, but also activities such as transport to and from the factory, local installation at the test laboratory and again at the factory, untanking and inspection, repetition of dielectic tests etc. For this reason the IEC standards also permits demonstration of the short circuit ability using calculation and design considerations. In this paper the different parameters for short circuit withstand capability is calculated for a 1500KVA, 22KV/415V, Dyn11 Distribution Transformer.

Permanent-magnet synchronous generators (PMSGs) are increasingly being used in non-conventional energy systems such as solar, wind, small hydro etc. The advantages of a PMSG in comparison to other variable-speed generators are well known. A few of them are reduced weight, low cost, low losses, nearly maintenance free, higher efficiency, and high reliability. An attempt is made in this paper to present an exhaustive bibliography on the PMSG and its application in wind energy.

This paper presents an investigation of the temperature characteristics of the IN4148 signal diode and its suitability for use as a PTC temperature sensor. The IN4148 signal diode with a Negative Temperature Coefficient of -2mV/OC was used in the implementation of the sensor for a temperature range of 27OC to 100OC.A 5V6 Zener diode was used to maintain a constant voltage across the sensor placed in a ¼ bridge network. The output of the sensor was amplified by a differential amplifier and the negative temperature coefficient was converted to a positive coefficient by the use of an inverter circuit. The results obtained show an increase in the temperature coefficient from-2mV/OC of the diode to -40mV/OC at the output of the differential amplifier. The temperature coefficient is converted to positive with a value of 10mV/OC at the inverter output. This sensor circuit finds application with easy calibration due to the positive temperature coefficient in control of heating systems with a temperature range of 27OC to 100OC.

This paper presents a new dual active half bridge soft-switched isolated bi-directional dc-dc converter. In addition, unified ZVS is achieved in either direction of power flow with neither a voltage-clamping circuit nor extra switching devices and resonant components.Bi-directional power flow is obtained by the same power components and provides a simple efficient and galvanically isolated converter. The proposed converter is a good alternative to the full bridge isolated bidirectional dc-dc onverters in high power application and has distinct advantages like high power density, high efficiency and low cost application. The detailed design and operating principles are analyzed and described. The simulation results are verified with the experimental results.