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.

Errors Analysis in Distance Relay Readings with Presence of FACTS Devices

This  paper  presents studying the  performance of  distance impedance relay with the presence of  FACTS devices .Also  the measured  impedance  at   the  relaying  point  in  the  presence  of  series FACTS device SSSC , and  shunt FACTS device called STATCOM are obtained. A detailed  model of both SSSC and STATCOM  is  introduced  and  then  the  faulty  system is studied analytically , where  the  errors in the measured  impedance of distance impedance relay   are  introduced as a result of the presence of  series  and  shunt  FACTS  devices. The analysis results show the effect of impacting the FACTS devices location, the values of inserted SSSC and STATCOM voltages (operational conditions) and also the fault resistance values. Keywords: Distance Relay, FACTS, STATCOM, SSSC

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 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

INFLUENCE OF TCSC FACTS DEVICE ON STEADY STATE VOLTAGE STABILITY

The influence of series Flexible AC Transmission Systems (FACTS) device namely, Thyristor-Controlled Series Capacitors (TCSC) on the steady state voltage stability is the main objective of this paper. The Line stability Index LSI under excepted lines outage contingencies is used to identify the critical line which is considered as the best location for TCSC. A modal analysis is used to define the weakest bus of the studied system. The FACTS device is implemented and included into the Newton-Raphson power flow algorithm, and the control function is formulated to achieve the voltage stability enhancement goal. The analysis is preformed on standard IEEE 30 bus system. The proposed scheme are tested under different loading conditions and different nonlinear voltage dependent loads. The simulation results demonstrate the feasibility and effectiveness of the device and the proposed algorithm