This paper presents the investigation of analytical models for the approximation of conduction and switching losses of the power-switch network in a three-phase AC-DC matrix rectifier. Analytical models of conduction and switching losses can provide circuit designers with a measurable way to approximate the total losses of the given power converter at different operating points so as to estimate the trend of the loss versus the change of the operating points.
1. Input Power Factor Correction (PFC): The PFC rectifier shall be power factor corrected so as to maintain an input power factor of 0.99 @ loads > 40% to unity to ensure generator compatibility and avoid reflected harmonics from disturbing loads sharing the utility power. The rectifier output shall be filtered with a ripple current not exceeding 1% rms over the allowable continuous input voltage range.
The power inverter needs to operate in a special manner for neutral current mitigation. Besides the power inverter, a feasible three-phase ES system includes a PLL (Phase Locked Loop) block, single-phase d-q transformation block and a Particle Swarm Optimization (PSO) based controller.In order to acquire accurate feedback, all variables in three- phase ES system should be synchronized under a fixed fundamental frequency. This is realized by the installation of a PLL block which generates the fundamental system frequency and provides a reference vector with 0° phase angle. The line voltage V sA is used as the reference vector. The single phase d-q transformation block decouples each current and
ABSTRACT: The electric field strength near a high voltage power transmission line can be greater than maximum permissible values. Therefore it is important to know the limits of these areas. It is presented in the paper that the expressions and calculations of the electric field strength at any observation point near the three-phase line dependently both on geometrical parameters of the line and coordinates of the observation point. The 2D approach is used for obtaining expressions which we can calculate electric field strength in any point near the line. The analytically calculated values are compared with the numerically calculated ones.
line conditioners. The term "power conditioning" used in this book has much broader meaning than the term harmonic filtering." In other words, the power conditioning is not confined to harmonic filtering, but contains harmonic damping, harmonic isolation, harmonic termination, reactive-power control for power factor correction, power flow control, and voltage regulation, load balancing, voltage-flicker Suction, and/or their combinations. Active power line conditioners are based on leading-edge power electronics technology that includes power conversion circuits, power semiconductor devices, analog/digital signal processing, voltage/current sensors, and control theory. Concepts and evolution of electricpower theory are briefly described below. Then, the need for a consistent set of power definitions is emphasized to deal with electric systems under non-sinusoidal conditions. Problems with harmonic pollution in alternating current systems (ac systems) are classified, including a list of the principal harmonic-producing loads. Basic principles of harmonic compensation are introduced. Finally, this chapter describes the fundaments of power flow control. All these topics are the subjects of scope, and will be discussed deeply in the following chapters of the book. The instantaneous power theory, or ―the p-q theory,‖ makes clear the physical meaning of what instantaneous real and imaginary power is in a three-phase circuit. Moreover, it provides insight into how energy flows from a source to a load, or circulates between phases, in a three- phase circuit. This theory can be used in the design and understanding of FACTS (Flexible AC Transmission System) compensators. The book introduces many concepts in the field of active filtering that are unique to this edition. It provides a study tool for final year undergraduate students, graduate students and engineers dealing i-th harmonic pollution problems, reactive power compensation or power quality in general. 2 EXISTING SYSTEM
Embedded power grids are recently becoming popular in different fields, for example more electric aircraft (MEA) . The MEA concept has introduced different advantages for the aircraft industry, such as reduced maintenance requirements, weight decrease, passenger comfort, and increased reliability. However, maintaining the advantages of the MEA highly relies on optimized on-board electrical network and power electronic conversion systems. Embedded power grids are composed by different power electronic converters usually connected together by passive filters. Due to the reduced grid size, the interaction between the converters is often not negligible, leading to undesirable and often unstable behavior. The easier and more common technique used to reduce this effect is to increase the size of passive filters that interface the converters to the grid. This approach permits to moderate the interactions and consequently allows designing the controllers independently. A filter size increment however, implicates a growth in the overall system dimension, weight and cost. The
In many important applications for power electronics such as renewable energy generation, motor drives, power quality, and micro grid, etc., the three-phase dc–ac converters are critical components as the power flow interface of dc and ac electrical systems . As shown in Fig1, a dc–ac voltage source converter with a corresponding filter is typically used to convert the energy between the dc bus and the three-phase ac sources, which could be the power grid, generation units, or the electric machines depending on the applications and controls Since the power electronics are getting so widely used and becoming essential in the energy conversion technology, the failures or shutting down of these backbone dc–ac converters may result in serious problems and cost. It is becoming a need in many applications that the power converters should be reliable to withstand some faults or disturbances in order to ensure certain availability of the energy supply . A good example can be seen in the wind power application, where both the total installed capacity and individual capacity of the power conversion system are relatively high. The sudden disconnection of the power converter may cause significant impacts on the grid stability and also on the high cost for maintenance/repair. As a result, transmission system operators (TSOs) in different countries have been issuing strict requirements for the wind turbine behavior under grid faults. As shown in Fig. 2, the wind power converter should be connected (or even keep generating power) under various grid voltage dips for certain time according to the dip severity, and in someuncritical
Abstract— An electric supply system should invariably show ideal sinusoidal voltage and current signals at every consumer end. But in fact electric utilities hardly find such desirable conditions due to several factors. Use of wide variety of domestic and industrial equipments is one of the reasons. In order to improve the performance to cope up with technological advancements, modern semiconductor based converters are often used. These equipments are often referred to as Power Electronics loads. Solid state control of ac power using thyristors and other semiconductor switches is widely employed to feed controlled electricpower to electric loads, such as adjustable speed drives, furnaces, computer power supplies, electrical transportation systems, electro domestic appliances etc. The objective of the paper is to study, simulate and design a shunt active power filter capable of compensating current harmonics generated at the supply side due to presence of such non-linear loads. The basic topology of the shunt active filter is a PWM controlled three-phase voltage source inverter bridge. A SCR or diode based rectifier is connected to the utility and the PWM controlled inverter generates specific current harmonics. These generated harmonics are injected into the source in phase opposition to the harmonics generated by the load. Thus harmonic cancellation takes place, so that these harmonics are not drawn from the source. In this paper, harmonic waveforms are generated in MATLAB software based on Fourier series of the ideal wave shapes created at the supply lines due to non-linear loads. A selection criterion for different components of the active filter has been made.
In this chapter, a new hardware/software design and implementation of an Induction Motor (IM) drive control topology is presented. Power electronic applications such as three-phase inverters require an accurate switching frequency for the gating signals of the switches. This design uses a System-on-Chip (SoC) approach implemented on a Field Programmable Gate Array (FPGA). The SoC includes the FPGA fabric and an on-chip processor. The on-chip processor is used for high-level programing, while the FPGA programmable fabric is used to create precise gating signals and fast parallel calculations for a three-phase inverter. These signals are generated in the hardware side of the design. Floating-point calculations and the control flow of the whole design are managed by the SoC. This method is suitable for any power electronic application where precise gating signals are required.
Abstract: Problem statement: Now days, power quality has been given attention due to the intensive use of power electronic equipments in all types of industries such as steel, paper, textile industries and so on. These power electronic devices induce harmonic distortion into the supply lines which gives rise to many undesirable effects. Approach: This study presents a new method for harmonic and reactive power compensation with a Fuzzy logic controller and a new control algorithm for active power filter to eliminate harmonics and compensate the reactive power of threephase diode bridge rectifier with RL load. The Fuzzy logic controller was used to predict the reference current values and the firing pulses were generated using hysteresis current controller. The system was modeled and simulated using MATLAB/SIMULINK power system toolbox. Results: The total harmonic distortion for the system is reduced from 29.16-1.08% using the proposed fuzzy logic controller based shunt active filter. Conclusion: The simulation results found were quite satisfactory to eliminate harmonics and improve the power factor for non linearloads.
A micro-grid can be defined as a portion of an electricpower distribution system that is located downstream of the distribution substation and includes a variety of distributed generation and storage systems and various loads. A micro- grid is different from a main grid system, which can be considered as an unlimited power so that load variations do not affect the stability of the system. On the contrary, in a micro-grid, large and sudden changes in the load may result in voltage transient of large magnitudes in the AC bus. Moreover, the proliferation of switching power converters and nonlinear loads with large rated power can increase the contamination level in voltage and current waveforms in a micro-grid, forcing to improve the compensation
Power distribution systems have different characteristics from transmission systems. They are characterized as Radial meshed structures; Unbalanced networks/loads . A distribution system originates at a substation where the electricpower is converted from the high voltage transmission system to a lower voltage for delivery
Power-factor correction can provide many benefits, including increasing the capacity of distribution transformers and lines, reducing the power loss of distribution feeders, improving voltage drops, reducing electric bills for power consumers, etc. Hence, shunt capacitor banks are commonly installed in industrial plants to provide reactive power. When the capacitor is energized, the result is an inrush current and transient overvoltage. Such transient phenomena will shorten the lifetime of the capacitor and damage the contacts of the circuit breaker or electromagnetic switch. Moreover, the transients may lead the sensitive equipment to operate abnormally and could also bring about problems with power quality.
Fig. 8 shows the responses of the two algorithms, particularly the initial portion of the ramp. In Table III the characteristics of both responses in this case are reported. From Fig. 8 it can be noticed that on a frequency ramp response, which represents the most significant operating situation for aerospace power generators, the SSLKF-PLL presents a negligible tracking delay and a steady-state tracking error close to zero. However, for a 60 Hz bandwidth, the steady-state oscillations amplitude is quite larger than the DFT one, even though such amplitude can be still considered acceptable, as it remains lower than 0.5% of the tracked frequency. In order to avoid the introduction of wider oscillations, which can negatively affect a controller using the proposed PLL, it is advisable to select a bandwidth value lower than 60 Hz.
The Arduino Uno microcontroller was used as for the control function in this system. Arduino is a low power CMOS 8-bit microcontroller based on AVR enhanced RISC architecture. The execution of instructions in a single clock cycle leads to the achievement of 1 MIPS, allowing the designer to optimize power consumption and processing speed. The arduino has an inbuilt Analog-to-Digital Converter (ADC) which converts analog voltage on a pin to a digital number. The analog pins on the Arduino Uno Microcontroller (A0 to A5) are connected to the ADC. The ADC on the Arduino is a 10-bit ADC, meaning it has the ability to detect 1024 (210) discrete analog levels. Since the ADC can read
ABSTRACT: The increasing use of power electronics-based loads (adjustable speed drives, switch mode power supplies, etc.) to improve system efficiency and controllability is increasing the concern for harmonic distortion levels in end use facilities and overall power system. The application of passive tuned filters creates new system resonances which are dependent on specific system conditions. In addition, passive filters often need to be significantly over-rated to account for possible harmonic absorption from the power system. Passive filter ratings must be coordinated with reactive power requirements of the loads. Parallel (or shunt) active filters have been recognized as a valid solution to current harmonic and reactive power compensation of non-linear loads. The basic principle of Shunt Active Power filter is that it generates a current equal and opposite in polarity to the harmonic current drawn by the load and injects it to the point of coupling thereby forcing the source current to be pure sinusoidal. The control strategy is Synchronous Detection Algorithm. This technique relies in the fact that the threephase currents are balanced. The average power is calculated and divided equally between the three phases. The signal is then synchronized relative to the mains voltage for each phase. Then the desired reference current is evaluated.
Installation of distributed generators (DGs) to form a micro grid can be beneficial for both the consumers and power utilities with local power generation . The capacity of the feeders is increased with properly sited DG; however, it does not necessarily improve in system reliability or power quality (PQ) . It cannot be assumed that DG automatically improves system reliability, and action may be required to ensure that reliability . One of the key actions is a coordinated control of the DGs and the compensating devices. Power generation while maintaining the PQ both in grid- connected and islanded mode is the ultimate goal of such reliable micro grid. In a modern micro grid, mitigation of the PQ events can be achieved by monitoring and compensating through power electronic devices . One of the major PQ problems in a micro grid with high penetration of DGs is the voltage drop. Usually, a 10% voltage drop is acceptable in a micro grid . The problem of voltage regulation is also present in three-phase operation. Application of three-phase converter- based DGs is very common in a micro grid and with the increasing number of three-phase micro sources has raised concern about PQ . In a low- voltage distribution network with small DGs (rooftop photovoltaic’s), voltage regulation problem exists usually at the end of the feeders . However, in a micro grid, with autonomous
 F. Blaabjerg, R. Teodorescu, M. Liserre, and A. V. Timbus, “Overview of control and grid synchronization for distributed power generation systems,” IEEE Trans. Ind. Electron., vol. 53, no. 5, pp. 1398–1409,Oct. 2006.  J. M. Carrasco, L. G. Franquelo, J. T. Bialasiewicz, E. Galván, R. C.P. Guisado, M. Á. M. Prats, J. I. León, and N. M. Alfonso, “Power- electronic systems for the grid integration of renewable energy sources:A survey,” IEEE Trans. Ind. Electron., vol. 53, no. 4, pp. 1002–1016, Aug. 2006.
India is a country of 1.32 billion population with 221 million registered vehicles on the road. Of these, 933950 three wheelers entered service in the year 2015-16 (114% increase from 2005-06). With atmospheric pollution and emission norms in mind, it is essential that we bring down the emission of vehicles. Tail pipe emission reduction is one of the ways to achieve that but, it is a difficult process. This paper explores the alternative. This work describes a methodology for retrofitting the conventional drivetrain of a vehicle with an electricpower unit. This work describes the development of a real world drive cycle for three wheeler auto rickshaws in Bengaluru city. For this, the micro trip generation method is employed, which captures the driving conditions encountered by the vehicle on a regular working day. A Bajaj RE 4 stroke CNG vehicle is used as the test vehicle throughout the process. A GPS based data logging system VBOX 3i is used for data acquisition. The vehicle dynamics are simulated to determine the power rating required for the electric motor to retrofit the IC engine using one dimensional longitudinal acceleration analysis. Coast down test results determine aerodynamic drag and rolling resistance coefficients. Dyno test helps us to understand the torque requirements for the electric motor to be retrofitted. The results of the mathematical model and the dyno test are then used to find a suitable electric motor. The adopted methodology in this work can be used to find the suitable power train replacement for any vehicle.
The programmable precision test power supply adopted direct frequency synthesis (DDS) technology. The high-precision standard power source was composed of CPLD, DSP, high-speed high-precision DA and high-fidelity power amplifier which was widely used in electrical measurement, thermal engineering, etc. of power systems. Instrumentation field [1-15]. The test power could output high-precision voltage and current with adjustable