Modelling and analysis of multi-junction solar cells to improve the conversion efficiency of photovoltaic systems
- Authors: Das, Narottam , Al Ghadeer, Abdulmohsen , Islam, Syed
- Date: 2014
- Type: Text , Conference proceedings , Conference paper
- Relation: 24th Australasian Universities Power Engineering Conference, AUPEC 2014; Perth, Australia; 28th September-1st October 2014 p. 1-5
- Full Text: false
- Reviewed:
- Description: This paper presents modelling and analysis of multi-junction solar cells to improve the conversion efficiency of photovoltaic (PV) power generation systems. For this modelling, Matlab/Simulink tool is used to obtain the simulation results. The modelling of a single junction solar cell can be performed by single or double diode models. From the simulation results, it was found that the double diode model is more accurate than the single diode model. Hence, the double diode model is used to simulate dual and triple junction solar cells. The simulations were performed under varying the critical factors, such as temperature and solar irradiance. The effect of these factors was clearly demonstrated on the I-V and P-V characteristics of the solar cells. It was found that the temperature increases, short circuit current increases slightly and open circuit voltage drops significantly. Consequently, the PV power generation decreases considerably. However, when the irradiance increases, the short circuit current increases slightly and the open circuit voltage increases significantly. Consequently, the power generation increases considerably and the conversion efficiency increases of the PV systems.
Offline to online mechanical deformation diagnosis for power transformers
- Authors: Hashemnia, Naser , Masoum, Mohammad , Abu-Siada, Ahmed , Islam, Syed
- Date: 2014
- Type: Text , Conference proceedings , Conference paper
- Relation: 24th Australasian Universities Power Engineering Conference, AUPEC 2014; Perth, Australia; 28th September-1st October 2014 p. 1-5
- Full Text: false
- Reviewed:
- Description: Internal winding deformations of power transformers can be detected using the conventional offline frequency response analysis (FRA) which is a well-known and widely accepted tool for the detection of winding and core deformations. In addition of being offline technique, interpretation of FRA signature is based on graphical analysis that requires skilled personnel as there is no reliable standard code for FRA signature identification and quantification. This paper presents the possibility of using an alternative online technique based on construction a voltage-current (ΔV-I) locus of the operating transformer and considering it as a reference signature. In order to fully explore the performance and reliability of the new proposed approach particularly for real-life distribution transformers, the paper investigates and compares the performance of the proposed and the FRA approaches for disk space variation and axial displacement faults. The transformer distributed parameter model is used to simulate FRA signatures while a detailed three-dimensional finite element model is used to generate the ΔV-I louses for healthy and faulty operating conditions. Simulation results are compared to highlight the advantages and limitations of the two internal fault detection strategies.
A new control approach to improve the overall performance of DFIG-based WECS
- Authors: Khamaira, Mahmoud , Abu-Siada, Ahmed , Islam, Syed , Masoum, Mohammad
- Date: 2014
- Type: Text , Conference proceedings , Conference paper
- Relation: 24th Australasian Universities Power Engineering Conference, AUPEC 2014; Perth, Australia; 28th September-1st October 2014 p. 1-5
- Full Text: false
- Reviewed:
- Description: Doubly Fed Induction Generators (DFIGs) are currently extensively used in variable speed wind power plants due to their superior advantages that include reduced converter rating, low cost, reduced losses, easy implementation of power factor correction schemes, variable speed operation and four quadrants active and reactive power control capabilities. On the other hand, DFIG sensitivity to grid disturbances, especially for voltage sags represents the main disadvantage of the equipment. In this paper, a coil is proposed to be integrated within the DFIG converters to improve the overall performance of a DFIG-based wind energy conversion system (WECS). A proportional integral (PI) controller to control the charging and discharging of the coil is introduced. Simulation results reveal the effectiveness of the proposed topology in improving the overall performance of the WECS under study.
DFIG-based WECS fault ride through complying with Australian grid codes
- Authors: Khamaira, Mahmoud , Abu-Siada, Ahmed , Islam, Syed
- Date: 2014
- Type: Text , Conference proceedings , Conference paper
- Relation: 24th Australasian Universities Power Engineering Conference, AUPEC 2014; Perth, Australia; 28th September-1st October 2014 p. 1-5
- Full Text: false
- Reviewed:
- Description: Doubly Fed Induction Generators (DFIGs) are widely used in variable speed wind turbine owing to its superior advantages that include ability to extract more energy from turbine, capability to control active and reactive power independently and the use of reduced converter rating that reduces its overall cost. On the other side fluctuating output power, weak fault ride through capability and high sensitivity to grid disturbances are the main issues that affect DFIG performance. In this paper, superconducting magnetic energy storage (SMES) unit is proposed to improve the fault ride through (FRT) capability of DFIG-based wind energy conversion system (WECS) during voltage sag and voltage swell events in the grid side. A new control approach for SMES unit using hysteresis current controller (HCC) along with proportional integral (PI) controller is introduced. Australian grid codes are used to examine the capability of the proposed controller to improve the FRT of the DFIG and hence maintaining the wind turbine connection to the grid during studied faults. Simulations results show the effectiveness of the SMES controller in maintaining system parameters within safety margins that comply with the Australian grid codes.