Micro Grid
A.M. Dejamkhooy; M. Hamedi; H. Shayeghi; S.J. SeyedShenava
Abstract
A stand-alone microgrid usually contains a set of distributed generation resources, energy storage system and loads that can be used to supply electricity of remote areas. These areas are small in terms of population and industry. Connection of these areas to the national distribution network due to ...
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A stand-alone microgrid usually contains a set of distributed generation resources, energy storage system and loads that can be used to supply electricity of remote areas. These areas are small in terms of population and industry. Connection of these areas to the national distribution network due to the high costs of constructing transmission lines is not economical. Optimal utilization and economic management of production units and storage devices are important issues in isolated microgrids. During optimum utilization, of renewable energy harvesting is maximized and fuel cost of diesel units reduces as much as possible. In this paper, the optimization problem is designed and solved as Linear Programming (LP). The cost of diesel generator unit depends on its production. Also, the fact is considered that the efficiency of diesel generator units is not constant for all amount of production. As a solution for this challenge demand side management plans have been proposed. On the other hand, load uncertainty is considered in this paper. Several scenarios are simulated by GAMS software for different conditions of a typical microgrid. The simulation results show the success of the proposed method in reducing costs and fossil fuel consumption and increasing the consumption of renewable energy.
S.K. Gupta; S.K. Mallik
Abstract
The voltage stability margin (VSM) is an important indicator to access the voltage stability of the power system. In this paper, Flexible AC transmission systems (FACTS) devices like static synchronous compensator (STATCOM), static synchronous series compensator (SSSC), and unified power flow controller ...
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The voltage stability margin (VSM) is an important indicator to access the voltage stability of the power system. In this paper, Flexible AC transmission systems (FACTS) devices like static synchronous compensator (STATCOM), static synchronous series compensator (SSSC), and unified power flow controller (UPFC) have been deployed to enhance the VSM of the power system. The placement of the FACTS devices is decided based on contingency raking. For the top five critical contingencies, the most severe bus is selected based on bus voltage stability criticality index and degree centrality methods. The critical line is decided based on the values of the line stability index, fast voltage stability index, and line stability factor. The STATCOM and shunt part of the UPFC are placed at the critical bus, whereas the SSSC and series part of the UPFC are placed at the critical line for enhancing voltage stability. The proposed method for voltage stability enhancement using FACTS devices is tested and validated on the IEEE-14 bus system and the NRPG-246 bus system at different system loading scenarios. The impact of the placement of FACTS devices is validated in terms of VSM improvement.
Non-Linear Control Systems
N. Bagheri; H. Alipour
Abstract
In this paper, a new actuator fault detection and isolation method for a four wheel independent drive electric vehicle is proposed. Also, a controller based on sliding mode control method is proposed for lateral stability of the vehicle. The proposed control method is designed in three high, medium and ...
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In this paper, a new actuator fault detection and isolation method for a four wheel independent drive electric vehicle is proposed. Also, a controller based on sliding mode control method is proposed for lateral stability of the vehicle. The proposed control method is designed in three high, medium and low levels. At the high-level, the vehicle desired dynamics such as longitudinal speed reference and yaw rate reference are determined. The medium-level is designed to achieve desired traction force and yaw moment based on the sliding mode control. At the low-level, by defining and optimally minimizing a cost function, proper force or torque signals are determined to apply to the wheels. Moreover, this paper also presents a new method for actuator fault detection and isolation in electric vehicles. The proposed fault detection method uses comparison of sliding ratio of different wheels. Using the proposed method, value of the actuator fault and its position are accurately estimated and diagnosed. Then, the proposed controller is modified and adapted to new conditions using the fault identification results. Finally, the validity of proposed controller is confirmed by the conducted simulations in MATLAB and CARSIM environments.
Planing & Reliability
S. Abbasi; H. Abdi
Abstract
Although significant private investment is absorbed in different sectors of power systems, transmission sector is still suffering from appropriate private investment. This is because of the pricing policies of transmission services, tariffs, and especially for investment risks. Investment risks are due ...
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Although significant private investment is absorbed in different sectors of power systems, transmission sector is still suffering from appropriate private investment. This is because of the pricing policies of transmission services, tariffs, and especially for investment risks. Investment risks are due to the uncertain behaviour of power systems that discourage investors to invest in the transmission sectors. In uncertain environment of power systems, a proper method is needed to find investment attractive transmission lines with high investment return and low risk. Nowadays, wind power generation has a significant portion in total generation of most power systems. However, its uncontrollable and variable nature has turned it as a main source of uncertainty in power systems. Accordingly, the wind power generation can play a fundamental role in increasing investment risk in the transmission networks. In this paper, impact of this type of generation on investment risk and returned investment cost in transmission network is investigated. With different levels of wind power penetration, the recovered values of investment cost and risk cost in transmission network are calculated and compared. This is a simple method to find investment attractive lines in presence of uncertainties. Wherein, transmission network expansion planning (TNEP) is formulated as a multi-objective optimization problem with objectives of minimizing the investment cost, maximizing the recovered investment cost and network reliability. The point estimation method (PEM) is used to address wind speed variations at wind farms sites in the optimization problem, and the NSGA II algorithm is applied to determine the trade-off regions between the TNEP objective functions. The fuzzy satisfying method is used to decide about the final optimal plan. The proposed methodology is applied on the IEEE 24-bus RTS and simplified Iran 400 kV network.
Power Electronic
M. Eskandarpour Azizkandi; F. Sedaghati; H. Shayeghi
Abstract
In this paper, a new high efficiency, high step-up, non-isolated, interleaved DC-DC converter for renewable energy applications is presented. In the suggested topology, two modified step-up KY converters are interleaved to obtain a high conversion ratio without the use of coupled inductors. In comparison ...
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In this paper, a new high efficiency, high step-up, non-isolated, interleaved DC-DC converter for renewable energy applications is presented. In the suggested topology, two modified step-up KY converters are interleaved to obtain a high conversion ratio without the use of coupled inductors. In comparison with the conventional interleaved DC-DC converters such as boost, buck-boost, SEPIC, ZETA and CUK, the presented converter has higher voltage gain that is obtained with a suitable duty cycle. Despite the high voltage gain of the proposed converter, the voltage stress of the power switches and diodes is low. Therefore, switches with low conduction losses can be applied to improve the converter efficiency. Moreover, due to utilization of interleaving techniques, the input current ripple is low which makes the suggested converter a good candidate for renewable energy applications such as PV power system. Operation principle and steady-state analysis of the proposed converter in continuous conduction mode (CCM) and discontinuous conduction mode (DCM) are discussed in detail. Also, theoretical efficiency of the proposed converter is calculated. Finally, in order to evaluate the proposed converter operation by a renewable energy source such as a PV, the simulation results are presented. Moreover, a 220W prototype of the presented DC-DC converter is designed and implemented in the laboratory to verify its performance.
Flexible AC TransmissionSystems (FACTs) Devices
A. Mohammadpour Shotorbani; S. Ghassem Zadeh; B. Mohammadi-ivatloo; S. H. Hosseini; L. Wang
Abstract
This paper investigates the robust decentralized nonlinear control of power flow in a power system using a new configuration of UPFC. This structure comprises two shunt converters and one series capacitor called as hybrid power flow controller (HPFC). A controller is designed via control Lyapunov function ...
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This paper investigates the robust decentralized nonlinear control of power flow in a power system using a new configuration of UPFC. This structure comprises two shunt converters and one series capacitor called as hybrid power flow controller (HPFC). A controller is designed via control Lyapunov function (CLF) and adaptive observer to surmount the problems of stability such as tracking desired references, robustness against uncertainties, rejecting the disturbances, and remote data estimation. The suggested control scheme is decentralized using adaptive observer to estimate the non-local varying parameters of the system. Stability of the closed loop system is proved mathematically using Lyapunov stability theorem. Performance of the proposed finite-time controller (FT-C) is compared to another suggested exponentially convergent nonlinear controller (ECN-C) and a conventional PI controller (PI-C). Settling time of the state variables are diminished to a known little time by FT-C in comparison with ECN-C and PI-C. Simulation results are given to validate the proposed controllers. Effects of model uncertainties such as parameter variation in the transmission line and the converters are studied and properly compensated by the proposed controllers. The impact of the control gain and the communication time-delay is shown using the Bode diagram analysis.
Power System Stability
M. Kazeminejad; M. Banejad; U. Annakkage; N. Hosseinzadeh
Abstract
Static voltage stability is considered as one of the main issues for primary identification before voltage collapsing in distribution systems. Although, the optimum siting of distributed generation resources in distribution electricity network can play a significant role in voltage stability improving ...
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Static voltage stability is considered as one of the main issues for primary identification before voltage collapsing in distribution systems. Although, the optimum siting of distributed generation resources in distribution electricity network can play a significant role in voltage stability improving and losses reduction, the high penetration level of them can lead to reduction in the improvement of load-ability. Moreover, the rapid variation and types of loads in distribution networks will have a significant impact on the maximum load-ability across the whole system. In this paper, a modified voltage stability index is presented with regard to distributed generation units (DG) along with two-tier load model. By applying the Imperialist Competition Algorithm (ICA), the best size of DG with corresponding of DG placement is used to improve the voltage stability and reducing the losses. It is shown in the paper that the DG penetration level can have influence on load-ability of the system and also the voltage regulators performance. The simulation results on the standard IEEE-13 Bus test feeder illustrate the precision of studies method and the load-ability limits in the system, taking into account the high penetration level of distributed generation units.
Micro Grid
K. Mazlumi; A. Shabani
Abstract
In recent years, most of the loads and distributed generations are connected to the AC grid through the power electronic converters. Using the DC grid beside the AC grid can reduce the conversion stages and power losses. Protection of the DC grids is a challenging issue because of the new structures ...
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In recent years, most of the loads and distributed generations are connected to the AC grid through the power electronic converters. Using the DC grid beside the AC grid can reduce the conversion stages and power losses. Protection of the DC grids is a challenging issue because of the new structures of DC grids and fast transients of the DC faults. This paper studies the protection of the low voltage DC (LVDC) system in the presence of the photovoltaic (PV) and energy storage systems (ESS). An LVDC system consisting of a DC microgrid is considered and Different operating modes are analyzed. DC faults behavior and protection challenges are discussed for each mode through simulations employing MATLAB software. Finally, some methods are presented to solve the protection challenges. The results show that changing the protection arrangement of the system and choosing suitable control logics for the ESS and the PV prevent the unwanted outage of the loads and provide the possibility of the microgrid operation in islanded mode.
A.T. Alahmad; A. Saffarian; S.G. Seifossadat; S.S. Mortazavi
Abstract
The widespread adoption of microgrids in electric power systems has brought numerous advantages such as decentralized control, reliability, cost-effectiveness, and environmental benefits. However, one of the most critical challenges faced by islanded microgrids is ensuring frequency and voltage stability. ...
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The widespread adoption of microgrids in electric power systems has brought numerous advantages such as decentralized control, reliability, cost-effectiveness, and environmental benefits. However, one of the most critical challenges faced by islanded microgrids is ensuring frequency and voltage stability. This paper addresses these stability issues that arise when microgrids operate independently, disconnected from the main network through the point of common coupling (PCC). These microgrids rely on renewable resources like photovoltaic (PV) systems, wind turbines, and energy storage systems, which often require DC to AC conversion through inverters to simulate synchronous generators. To overcome the frequency and voltage stability challenges, this research utilizes the droop control technique to regulate the active and reactive power of distribution generators (DGs). The droop control technique is implemented and simulated using MATLAB software, specifically employing a multi-DC bus-based inverter. The simulation results demonstrate that the DGs successfully supply the required total power to meet load demands while maintaining frequency and voltage stability. Through the droop control technique, active and reactive power sharing is achieved, ensuring stability at nominal values. The DGs can effectively maintain a constant power profile at desired values, even in the presence of static and dynamic loads.
Power System Operation
H. Mousavi-Sarabi; M. Jadidbonab; B. Mohammadi ivatloo
Abstract
The impact of different energy storages on power systems has become more important due to the development of energy storage technologies. This paper optimizes the stochastic scheduling of a wind-based multiple energy system (MES) and evaluates the operation of the proposed system in combination with ...
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The impact of different energy storages on power systems has become more important due to the development of energy storage technologies. This paper optimizes the stochastic scheduling of a wind-based multiple energy system (MES) and evaluates the operation of the proposed system in combination with electrical and thermal demand-response programs and the three-mode CAES (TM-CAES) unit. The proposed wind-integrated MES consists of a TM-CAES unit, electrical boiler unit, and thermal storage system which can exchange thermal energy with the local thermal network and exchange electricity with the local grid. The electrical and thermal demands as well as wind farm generation are modeled as a scenario-based stochastic problem using the Monte Carlo simulation method. Afterwards, the computational burden is reduced by applying a proper scenario-reduction algorithm to initial scenarios. Finally, the proposed methodology is implemented to a case study to evaluate the effectiveness and appropriateness of the proposed method.
Power Electronic
R. Esmaeilzadeh; A. Ajami; M. R. Banaei
Abstract
This paper proposes a new two-stage inverter based on transformer-less high gain DC-DC converter for energy conversion of a photovoltaic system. The designed system consists of a high gain DC-DC converter cascaded with a three-phase inverter. The proposed DC-DC converter has a simple structure, and it ...
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This paper proposes a new two-stage inverter based on transformer-less high gain DC-DC converter for energy conversion of a photovoltaic system. The designed system consists of a high gain DC-DC converter cascaded with a three-phase inverter. The proposed DC-DC converter has a simple structure, and it has one switch in its structure. The output voltage of the DC-DC converter supplies DC source for the inverter part of the multi-stage inverter. The advanced two-stage inverter sample was fabricated, then the findings of the acquired simulation and hardware warranted the configuration applicability. Finally, the MATLAB/SIMULINK is employed for the simulation of PV-battery system. The obtained results revel that the proposed power conversion system effectively chases the load and generation fluctuations and also properly handles the power mismatches in PV-battery system.
Micro Grid
H. Shayeghi; A. Younesi
Micro Grid
M. Majidi; S. Nojavan
Abstract
Utilization of energy storage system (ESS) in microgrids has turned to be necessary in recent years and now with the improvement of storage technologies, system operators are looking for an exact modeling and calculation for optimal sizing of ESS. In the proposed paper, optimal size of ESS is determined ...
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Utilization of energy storage system (ESS) in microgrids has turned to be necessary in recent years and now with the improvement of storage technologies, system operators are looking for an exact modeling and calculation for optimal sizing of ESS. In the proposed paper, optimal size of ESS is determined in a microgrid considering demand response program (DRP) and reliability criterion. Both larger and small-scale ESSs have their own problems. A large-scale ESS reduces microgrid operating cost but it includes higher investment costs while a small-scale ESS has less investment cost. The main goal of the proposed paper is find optimal size of ESS in which microgrid investment cost as well as operating cost are minimized. Since the renewable units may not have stable production and also because of the outages that conventional units may have, ESS is utilized and then a reliability index called reliability criterion is obtained. Furthermore, effects of reliability criterion and DRP on optimal sizing of ESS are evaluated. A mixed-integer programing (MIP) is used to model the proposed stochastic ESS optimal sizing problem in a microgrid and GAMS optimization software is used to solve it. Five study cases are studied and the results are presented for comparison.
Electric Mechinces & Drive
M. Jafarboland; S. M. Mousavi
Abstract
The purpose of this paper is the calculation of Unbalanced Magnetic Force (UMF) in permanent magnet brushless DC (PMBLDC) machines with diametrically asymmetric winding and investigation of UMF variations in the presence of phase advance angle. This paper presents an analytical model of UMF in surface ...
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The purpose of this paper is the calculation of Unbalanced Magnetic Force (UMF) in permanent magnet brushless DC (PMBLDC) machines with diametrically asymmetric winding and investigation of UMF variations in the presence of phase advance angle. This paper presents an analytical model of UMF in surface mounted PMBLDC machines that have a fractional ratio of slot number to pole number. This model is according to a 2-D analytical field model. By an appropriate choice for slot number to the pole number ratio, the magnitude of UMF is zero and this is achieved only when the stator slot and coils distribution are symmetrical about the diameter of the machine. The presented model is validated by 2-D finite element analysis and a good agreement is obtained between them. Also, UMF is calculated in the presence of different phase advance angles. UMF was calculated for 33-slot/34-pole and 36-slot/34-pole external rotor machines with analytical and finite element method. A machine with 33-slot/34-pole has significantly larger UMF than the 36-slot/34-pole machine. Also, UMF is calculated for the 33-slot/34-pole machine in the presence of phase advanced angles and results show that the magnitude of UMF changes with the amount of phase advance angle periodically. The impact of phase advance angle method on the magnitude of UMF is investigated for the first time by finite element method. Due to increasing or decreasing of the magnitude of UMF in the presence of different phase advance angles, the magnitude of UMF is an important feature in the selection of appropriate phase advance angle.
Power System Operation
N. Kumar; S. Dahiya; K.P.Singh Parmar
Abstract
The microgrid (μG) is an integration of distributed generation and local loads with energy storage system. Cost minimization is one of the main objectives in modern power systems.Economic dispatch(ED) is a fundamental problem related to μG and the conventional grid. Economic dispatch(ED) provides ...
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The microgrid (μG) is an integration of distributed generation and local loads with energy storage system. Cost minimization is one of the main objectives in modern power systems.Economic dispatch(ED) is a fundamental problem related to μG and the conventional grid. Economic dispatch(ED) provides the optimal output of generators in order to reduce the total operating cost. Emission dispatch (EMD) is one of the other major problems associated with CG. The emission dispatch (EMD) solution provides the optimal generator operation to reduce harmful pollutants for a specific load demand. Multi-objective economic emission dispatch (MEED) provides a compromise between ED and EMD. In this paper, two test systems have been proposed. Test system one consists of Six CG. Static ED, EMD, and MOEED analysis has been provided for test system one. Test system two consists of four CG, One wind turbine generator (WTG), and one photovoltaic module (PVM).This paper intends to provide sensitivity analysis and uncertainty regarding the curtailment cost of RES. CPLEX solver in GAMS has been proposed to optimize the three fundamental problems. Comparative study and sensitivity analysis show optimal results, and the GAMS solver provides a more comprehensive framework. Reduction in cost due to uncertainty in ED is 9.58% as compared to 9.7% for test system two. The cost has been reduced in MEED by 9.33% as compared to 9.46%. MEED comparison shows the increment in cost of 2.66 %, but the emission is reduced by 18.98 % for test system two.
M. Hosseinpour; S. Mansoori; H. Shayeghi
Abstract
A new optimization method is proposed in this paper for finding the firing angles in multi-level voltage source inverters to eliminate low-order selective harmonics and reduce total harmonic distortion (THD) value of the output voltage. For thid end, Fourier series is used for calculating objective function ...
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A new optimization method is proposed in this paper for finding the firing angles in multi-level voltage source inverters to eliminate low-order selective harmonics and reduce total harmonic distortion (THD) value of the output voltage. For thid end, Fourier series is used for calculating objective function and selecting specific harmonics. Regarding the nature and complexity of the employed non-algebraic equations in the optimization problem for achieving the optimal angle in the multi-level inverter, a recent developed meta-heuristic method known as Salp Swarm Algorithm (SSA) is presented. In the proposed method, the optimal angles for a given multi-level inverter are obtained based on the objective function such that the magnitudes of the selective harmonics and the THD value of the output voltage are reduced. The method is applied on a cascaded H-bridge type five-level inverter. The simulation results illustrate that the magnitudes of the selective harmonics and the THD percentage of the output voltage have been reduced through selecting the optimal switching angle by the proposed optimization algorithm. The result of this method are compared with those of SPWM method. Moreover, the performance of SSA algorithm with respect to PSO algorithm is compared which shows its rapid convergence speed and less THD value.
A. Rastgou; J. Moshtagh; S. Bahramara
Abstract
In this paper, power distribution planning (PDP) considering distributed generators (DGs) is investigated as a dynamic multi-objective optimization problem. Moreover, Monte Carlo simulation (MCS) is applied to handle the uncertainty in electricity price and load demand. In the proposed model, investment ...
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In this paper, power distribution planning (PDP) considering distributed generators (DGs) is investigated as a dynamic multi-objective optimization problem. Moreover, Monte Carlo simulation (MCS) is applied to handle the uncertainty in electricity price and load demand. In the proposed model, investment and operation costs, losses and purchased power from the main grid are incorporated in the first objective function, while pollution emission due to DGs and the grid is considered in the second objective function. One of the important advantages of the proposed objective function is a feeder and substation expansion in addition to an optimal placement of DGs. The resulted model is a mixed-integer non-linear one, which is solved using a non-dominated sorting improved harmony search algorithm (NSIHSA). As multi-objective optimization problems do not have a unique solution, to obtain the final optimum solution, fuzzy decision making analysis tagged with planner criteria is applied. To show the effectiveness of the proposed model and its solution, it is applied to a 9-node distribution system.
Micro Grid
V. Amir; Sh. Jadid; M. Ehsan
Abstract
: In this paper, the operation of a future distribution network is discussed under the assumption of a multi-carrier microgrid (MCMG) concept. The new model considers a modern energy management technique in electricity and natural gas networks based on a novel demand side management (DSM) which the energy ...
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: In this paper, the operation of a future distribution network is discussed under the assumption of a multi-carrier microgrid (MCMG) concept. The new model considers a modern energy management technique in electricity and natural gas networks based on a novel demand side management (DSM) which the energy tariff for responsive loads are correlated to the energy input of the network and changes instantly. The economic operation of MCMG is formulated as an optimization problem. In conventional studies, energy consumption is optimized from the perspective of each infrastructure user without considering the interactions. Here, the interaction of energy system infrastructures is considered in the presence of energy storage systems (ESSs), small-scale energy resources (SSERs) and responsive loads. Simulations are performed using MCMG which consists of micro combined heat and power (CHP), photovoltaic (PV) arrays, energy storage systems (ESSs), and electrical and heat loads in grid-connected mode. Results show that the simultaneous operation of various energy carriers leads to a better MCMG performance. Moreover, it has been indicated that energy sales by multi sources to main grids can undoubtedly reduce the total operation cost of future networks.
Dynamics
H. Shahsavari; A. Safari; J. Salehi
Abstract
This paper studies the theory and modeling manner of solid oxide fuel cell (SOFC) into power network and its effect on small signal stability. The paper demonstrates the fundamental module, mathematical analysis and small signal modeling of the SOFC connected to single machine infinite bus (SMIB) system. ...
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This paper studies the theory and modeling manner of solid oxide fuel cell (SOFC) into power network and its effect on small signal stability. The paper demonstrates the fundamental module, mathematical analysis and small signal modeling of the SOFC connected to single machine infinite bus (SMIB) system. The basic contribution of the study is to attenuate the low frequency oscillations by optimal stabilizers in the presence of SOFC. To optimize the performance of system, fuzzy logic-based power system stabilizer (FLPSS) is exploited and designed by particle swarm optimization (PSO) technique. To ensure the effectiveness of the proposed optimal stabilizers, the simulation process takes in three scenarios of operating conditions. The effectiveness of proposed PSO based FLPSS on the oscillations in the power system, including SOFC is extensively demonstrated through time-domain simulations and by comparing FLPSS with the results of other stabilizers approaches.
Renewable Energy
H. Shayeghi; Y. Hashemi
Abstract
This paper presents a model for line extension scheduled to participate in responsive loads in the power system aiming the improvement of techno-economical parameters. The model is studied with the presence of photovoltaic generators that produce variable power depending on the geographical condition. ...
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This paper presents a model for line extension scheduled to participate in responsive loads in the power system aiming the improvement of techno-economical parameters. The model is studied with the presence of photovoltaic generators that produce variable power depending on the geographical condition. The investment cost of the transmission expansion plan, demand response operation cost, generation costs and the sum of the voltage deviations are the four indices that the optimization problem is designed based on these four criteria. Objective functions are dynamic variables that change daily due to variation in generation and load. A multi-objective optimization method based on the analytic hierarchy technique is employed to solve the problem. The Pareto-optimal set is extracted with gravitational search style and the best solution is fund by AHT manner. Studies are carried out on the modified 30-bus and 24-bus IEEE test system to confirm the capability of the presented model. Two frameworks are defined to compare the suggested manner. A different amount of PV penetration is discussed in several scenarios. Also, load uncertainty is formulated and involved based on probability distribution function.
Electric Mechinces & Drive
Sh. Yadav; S.K. Mallik; A. Mishra
Abstract
Low Switching-based v/f -controlled induction motor (IM) drives are incredibly susceptible to torque harmonics and their Vibrations. These consequences lead to intensifying losses, damage drive, and can even turn out into shaft failure of high power/speed drives. In literature, numerous control ...
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Low Switching-based v/f -controlled induction motor (IM) drives are incredibly susceptible to torque harmonics and their Vibrations. These consequences lead to intensifying losses, damage drive, and can even turn out into shaft failure of high power/speed drives. In literature, numerous control algorithm based on pulse width modulation (PWM) has been reported for low switching-based IM drive. Nowadays, standard PWM techniques (Sinusoidal PWM (S-PWM), selective harmonic elimination (SHE) PWM) are being used as the solution in low-switching IM drives. In this manuscript, the proposed synchronous reference frame (SRF) based P-PWM scheme is analytically evaluated to minimise the torque harmonics and its vibration in low switching IM drive. In this paper, a specific case of four switching angles per quarter cycle (Sq=4) is considered in which the optimized switching angles are obtained while maintaining the quarter wave symmetry (QWS) and half wave symmetry (HWS) nature of the waveform. The proposed approach is validated on 1hp IM drive and compared with S-PWM and SHE-PWM with respect to torque spectrum and vibration under No Load and different loading conditions. Real-time waveforms are recorded using the SRF-based P-PWM technique and the TYPHOON-HIL hardware setup to demonstrate the superior performance of the SRF-based P-PWM in comparison to S-PWM and SHE-PWM, in terms of lower torque harmonics and their vibrations.
Power Electronic
E. Salari; M. R. Banaei; A. Ajami
Abstract
A non-isolated DC/DC converter with high transfer gain is proposed in this paper. The presented converter consists of the switched inductor and three-level converters. The DC/DC power converter is three-level boost converter to convert the output voltage of the DC source into two voltage sources. The ...
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A non-isolated DC/DC converter with high transfer gain is proposed in this paper. The presented converter consists of the switched inductor and three-level converters. The DC/DC power converter is three-level boost converter to convert the output voltage of the DC source into two voltage sources. The main advantages of DC/DC converter are using low voltage semiconductors and high gain voltage. The steady-state operation of the suggested converter is analyzed. A prototype is developed and tested to verify the performance of the proposed converter. To sum up, the MATLAB simulation results and the experimental results have transparently approved high efficiency of proposed converter as well as its feasibility.
Power Electronic
A. Ghaemi; M. R. Banaei; A. Safari
Abstract
One of the most efficient lighting technology is based on light-emitting diodes (LEDs). Common LED drivers with AC-input (50-60Hz) usually require a bulk electrolytic capacitor to decrease low-frequency ripple in the output. However, the critical element that limits the lifespan of the LED driver is ...
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One of the most efficient lighting technology is based on light-emitting diodes (LEDs). Common LED drivers with AC-input (50-60Hz) usually require a bulk electrolytic capacitor to decrease low-frequency ripple in the output. However, the critical element that limits the lifespan of the LED driver is the electrolytic capacitor. An isolated off-line LED driver is proposed in this paper, in which the required output capacitance is reduced so that the electrolytic capacitor can be omitted from the driver structure. The driver’s configuration and controlling method provide a high input power factor. Just a single switch and therefore a single controlling IC have been used in the proposed structure. The input power factor correction is implemented utilizing a boost-based method, and a novel structure is introduced for dc/dc conversion section. Power factor correction and dc/dc conversion are performed employing a simplistic and single controlling system. The output current feeding the LEDs is a high frequency pulsating current. Calculations, simulations and experimental waveforms of a laboratory prototype are presented to confirm the validity of the proposed driver.
Flexible AC TransmissionSystems (FACTs) Devices
A. Shahdadi; B. Z-M-Shahrekohne; S. M. Barakati
Abstract
More than one hundred countries are using wind energy due to their easy implementation, cheap energy, and high energy efficiency. Implementation of FACTS devices in Wind Energy Conversion Systems (WECS) has been dramatically improved due to cooperative and accurate performance of FACTS devices. However, ...
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More than one hundred countries are using wind energy due to their easy implementation, cheap energy, and high energy efficiency. Implementation of FACTS devices in Wind Energy Conversion Systems (WECS) has been dramatically improved due to cooperative and accurate performance of FACTS devices. However, dealing with wind turbine faults promptly is crucial. Short-term and long-term faults may have excessive voltage changes and inconstant active and reactive power injection into transmission line. In this paper, robustness and flexibility of SSSC, STATCOM, and UPFC FACTS devices connecting to a 9 MW SCIG-based wind farm under different time-domain fault conditions is investigated. Variety of system scenarios under fault conditions are surveyed in order to find the best Fault Ride Through (FRT) scheme for the system. To carry out this study, same rating and capacity is considered for all three FACTS devices which are employed at the grid-connected point of WECS to mitigate FRT problem. Moreover, the best compromised control mode of FACTS devices is sought by a power flow analysis. Additionally, to obtain a more perceivable view over the technical issues related to the voltage sag support, performance of FACTS devices is analyzed and compared with each other through the paper and at the final stage. A complete digital simulation of the system is executed in the MATLAB/SIMULINK environment and the results are presented to authenticate the performance of devices.
Energy Management
H. Shayeghi; E. Shahryari
Abstract
Utilizing distributed generations (DGs) near load points has introduced the concept of microgrid. However, stochastic nature of wind and solar power generation as well as electricity load makes it necessary to utilize an energy management system (EMS) to manage hourly power of microgrid and optimally ...
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Utilizing distributed generations (DGs) near load points has introduced the concept of microgrid. However, stochastic nature of wind and solar power generation as well as electricity load makes it necessary to utilize an energy management system (EMS) to manage hourly power of microgrid and optimally supply the demand. As a result, this paper utilizes demand response program (DRP) and battery to tackle this difficulty. To do so, an incentive-based DRP has been utilized and the effects of applying DRP on microgrid EMS problem have been studied. The objective functions of microgrid EMS problem include the total cost and emission. These metrics are combined in a multi-objective formulation and solved by the proposed multi-objective group search optimization (MOGSO) algorithm. After obtaining Pareto fronts, the best compromise solution is determined by using fuzzy decision making (FDM) technique. Studies have been employed on a test microgrid composed of a wind turbine, photovoltaic, fuel cell, micro turbine and battery while it is connected to the upper-grid. Simulation results approve the efficiency of the proposed method in hourly operation management of microgrid components.
