V/F control of Three Phase Induction Motor Drive with Different PWM Techniques

This paper presents a  v/f control of induction motor with different pulse width modulation ( PWM) techniques as sine triangle pulse width modulation ( SPWM), Third-harmonic  pulse width modulation (THPWM) and  Space vector pulse width modulation(SVPWM) using MATLAB SIMULINK. Induction motor modeled in the synchronous q-d reference frame. The performance of IM with full load torque is compared using these techniques for THD, harmonics spectra, utilization of dc supply voltage, fundamental peak of the output voltage and motor speed. The dynamic performance of IM using SVPWM under reference speed and load torque variations is studied also. The results show that the SVPWM is the efficient one because it’s superior performance characteristics. The operation of IM with v/f method for closed loop system is enhancement when SVPWM technique is applied. Keywords: Space vector modulation, SPWM, V/f control, Harmonic injection

MPPT Based on Power Mapping and Frequency Derivative

This article presents a method for harmonic mitigation and maximum power point tracking for a variable-speed grid-connected  wind turbine. The wind energy conversion system consists of a permanent magnet synchronous generator driven by variable-speed wind turbine. The output of the permanent magnet synchronous generator is connected to a single-switch three-phase boost rectifier to generate DC voltage, which feeds a current-controlled inverter to interface the system with the electric utility. The single-switch three-phase boost rectifier is an active power factor correction technique to maintain the power factor at the permanent magnet synchronous generator side to nearly unity and mitigate the permanent magnet synchronous generator current harmonics. To mitigate inverter output current and voltage harmonics, an LCL filter has been used. Acomplete analysis of the harmonic content has been done everywhere in the system. The results show that the proposed maximum power point tracking control strategy succeeded to track the maximum wind power irrespective of the wind speed. This strategy in presence of an LCL filter achieved harmonic mitigation at the permanent magnet synchronous generator and inverter output sides. Keywords: variable-speed wind turbine ; permanent magnet synchronous generator ; maximum power point tracking ; harmonic mitigation ; active power filter.

Analysis of Wind Turbine Driven Permanent Magnet Synchronous Generator under Different Loading Conditions

This paper proposes the configuration of a Wind Turbine generating system equipped with Permanent Magnet Synchronous Generator (PMSG). There are different types of synchronous generators, but the PMSG is chosen which has better performance due to higher efficiency and less maintenance. Since it can be used without a gearbox also implies a reduction of the weight of the nacelle and a reduction of costs. The model includes a wind turbine model, drive train model and PMSG model. The equations that explain their behavior have been introduced. The generator model is established in the d-q synchronous rotating reference frame. The proposed Wind Turbine Generator System (WTGS) has been implemented in MATLAB/SIMULINK software. The PMSG is operating in stand-alone which is loaded with different types of loads. The simulation results indicate the ability of wind driven PMSG to operate over wide range of operating conditions at different loading conditions and show effect of different load types in operation. Keywords: Permanent Magnet Synchronous Generator (PMSG), Wind Turbine, Wind Energy and WTGS MATLAB/SIMULINK

Optimal Choice and Allocation of FACTS Devices for Security-Constrained Economic Dispatch

Flexible AC transmission systems (FACTS) devices have provided new control facilities in power systems. Simultaneous optimization of type, location and parameters for FACTS devices is an important issue when a given number of FACTS devices are applied to the power system with the purpose of increasing system loadability. This paper presents the application of simulated annealing algorism (SA) to find optimal type, location and parameters of FACTS devices to achieve security-constrained economic dispatch (SCED). The overall cost function, which includes generation cost and installation cost of FACTS devices, should be minimized. The SCED constraints are generators, transmission lines and FACTS limits. Two types of FACTS devices are utilized in this study namely STATCOM as a shunt type and TCSC as a series type. In this study simulations were performed on IEEE 14-bus. Results of simulations are encouraging and could efficiently be employed for power system operations. Keywords: Allocation, Security-constrained economic dispatch (SCED), FACTS and simulated annealing (SA)

Optimal operation and battery management in a grid-connected microgrid

Recently, Smart grid is one the important concepts that improve the energy future. This paper proposes an economic optimization technique for battery management to reduce the operating cost of a grid-connected microgrid. The proposed microgrid includes photovoltaic, wind power, and battery storage system. The proposed objective concerns with determination of the optimal hourly management for the operating power system to meet the required profile of load demand. In addition to, the excess/lack amount of electricity can be sold to/purchased from the utility grid. Interior Search Algorithm (ISA), an efficient heuristic algorithm, is applied to solve the problem with an objective of total operational cost minimization. The optimization technique is applied to a typical microgrid system with different loading conditions as a case study to test its effectiveness. The proposed platform can be considered as a significant part of comprehensive energy management system (EMS). The simulation results indicate high potential savings for the total operating cost

Control and EMS of a Grid-Connected Microgrid with Economical Analysis

Recently, significant development has occurred in the field of microgrid and renewable energy systems (RESs). Integrating microgrids and renewable energy sources facilitates a sustainable energy future. This paper proposes a control algorithm and an optimal energy management system (EMS) for a grid-connected microgrid to minimize its operating cost. The microgrid includes photovoltaic (PV), wind turbine (WT), and energy storage systems (ESS). The interior search algorithm (ISA) optimization technique determines the optimal hour-by-hour scheduling for the microgrid system, while it meets the required load demand based on 24-h ahead forecast data. The control system consists of three stages: EMS, supervisory control and local control. EMS is responsible for providing the control system with the optimum day-ahead scheduling power flow between the microgrid (MG) sources, batteries, loads and the main grid based on an economic analysis. The supervisory control stage is responsible for compensating the mismatch between the scheduled power and the real microgrid power. In addition, this paper presents the local control design to regulate the local power, current and DC voltage of the microgrid. For verification, the proposed model was applied on a real case study in Oshawa (Ontario, Canada) with various load conditions