Voltage regulation (Total 349465 Papers Found)

After the synchronous interconnection of Turkish Power System to ENTSO-E CESA (former UCTE) System, inter-area oscillations in the range of 0.15 Hz are prone to occur, according to simulation studies. Therefore, some preventive measures should be considered in order to ensure stable operation of the network after the interconnection. This study summarizes the effects of following measures based on computer simulations: 1) Retuning of power system stabilizers (PSS) of the important power plants i ...
In the operation of distribution system, if the tap of transformer and capacitors regulators was frequently changed, these devices would be easily damaged. So it is necessary to lower the tap-changing and capacitors regulators times. The solution algorithm developed for this problem is based on a phase1-phase2 feasible directions approach. A new optimization algorithm, that can obtain the optimal solution of the multi-objective programming problem with consideration of lowering losses and tap ch ...
This paper presents a new design methodology of the transient voltage clamp (TVC), which operates by controlling inductor current slew rate in 4 Switch Buck Boost Converter (4SBB). When 4SBB operates in boost mode, the TVC circuit changes inductor current slew rate during load current step-down to achieve a faster voltage regulation. Due to the slow inductor current slew rate, traditional 4SBB could not respond rapidly to the load current transient. As a result, a large output voltage spike can ...
The single-stage forward and flyback derived converter topologies are widely preferred at low power applications. For high dc link voltage applications, research efforts focus on multi-level topologies. This paper proposes a new single-stage three-level (SSTL) isolated ac/dc PFC converter for high dc link voltage low-power applications achieved through an effective integration of ac/dc and dc/dc stages, where all of the switches are effectively shared between two operations. With the proposed co ...
This paper presents a new design strategy for an S-<italic>LCC</italic>-type compensation network in inductive power transfer (IPT) systems to achieve constant voltage output. It was found that four resonant elements (three capacitors and one inductor) can compose two symmetric T-type resonant tanks, which is well-known for its impedance transformation characteristic and reciprocity between voltage source and current source. A simplified analytical technique is used to calculate the ...
Since intermediate mechanical conversion mechanisms for speed, torque and motion conversion can be entirely eliminated, the direct-drive wave power generation attracts more and more attention. Among various proposed generators, the permanent-magnet (PM) vernier generator is considered as a viable solution for the wave energy harvesting. This generator can efficiently harness this low-speed and high-power energy source via a so-called vernier effect by utilizing the effective harmonic magnetic fi ...
We present a framework for the design and simulation of electrical distribution systems and short term electricity markets specific to the UK. The modelling comprises packages relating to the technical and economic features of the electrical grid. The first package models the medium/low distribution networks with elements such as transformers, voltage regulators, distributed generators, composite loads, distribution lines and cables. This model forms the basis for elementary analysis such as l ...
This paper proposes a robust adaptive voltage control of three-phase voltage source inverter for a distributed generation system in a standalone operation. First, the state-space model of the load-side inverter, which considers the uncertainties of system parameters, is established. The proposed adaptive voltage control technique combines an adaption control term and a state feedback control term. The former compensates for system uncertainties, while the latter forces the error dynamics to conv ...
Intentional islanding operation has recently been considered by some utilities to effectively use the available renewable energy generation. In this paper, an intentional islanding operation of hydro Distributed Generation (DG) is proposed. Governor and Automatic Voltage Regulation (AVR) are properly developed such that the DG exhibits a good dynamic response once a part of the network is islanded. A new adaptive load shedding scheme is also proposed to address the issue of overload or insuffici ...
PWM techniques allow the converter output voltage and current controls. If a high dynamic is required, then a local hardware feedback loop needs to be implemented. Therefore, a resonant current controller had been recently studied. Its specifications arc fast response, very low sensitivity to the load's electrical parameters, extremely low DHT, and a maximum inverter switching frequency firmly controlled. This novel modulator combines two structures: the first acts at lower frequencies for curre ...
A power supply on chip (SoC) has been attracted attentions of many researchers because it can realize ultimate minimization of the power supply. It is quite promising for ICT applications because its features, such as smaller volume, high frequency response, and so on, fit for requirement of POL used in ICT equipment. In this paper, we propose the novel concept of digitally controlled multiple output POLs suitable for power SoC. We also report the simulation and experimental results of the propo ...
Distributed Generation source are widely used because of their remarkable advantages. Photovoltaic (PV) cells which produce DC voltage in their output belong to these sources and should be connected to the network through a power electronic interface. At the other hand, considering PV characteristics show that maximum power can be extracted at the optimal operating point which depends on the solar radiation as well as ambient temperature. So, a DC-DC converter is usually used between PV module a ...
Phase-shift control strategy is adopted extensively in wireless charging system (WCS) to regulate inverter output voltage, and namely, adjusting system output power under various load conditions. However, when it comes to light load or even no-load, the lower the output power is, the larger phase angle should be — which could cause inverter output voltage waveform to be abnormal. So, how to satisfy system power conversion caused by a wide load range variation is an issue of significance f ...
The paper describes a control method for operating a variable switching frequency buck converter, designed to convert an input battery voltage of 4.5 to 8Vdc to an output voltage of 3.3Vdc with a maximum load current of 4Adc. The advantages of the control method are that the output voltage is tightly regulated and that high e ciency (over 90%) is maintained over a very wide range of load currents (40mA to 4Adc). The output voltage ripple, DC and transient voltage regulation (for 100:1 load trans ...
This paper presents the design of a highperformance sinusoidal pulse width modulation (SPWM) controller for three phase uninterruptible power supply (UPS) systems that are operating under highly nonlinear loads. The classical SPWM method is quite effective in controlling the RMS magnitude of the UPS output voltages. However, it is not good enough in compensating the harmonics and the distortion caused specifically by the nonlinear currents drawn by the rectifier loads. The distortion becomes mor ...
Owing to the development of highly efficient electric power converters, the number of studies on the construction of low-voltage dc (LVDC) systems is gradually increasing. To use LVDC distribution systems, voltage regulation methods to compensate for the voltage drop and to limit the voltage unbalance are essential. In a bipolar LVDC distribution system, a voltage drop and voltage unbalance could occur because of the load current and the variation in the amount of power supplied to the poles. Ho ...
Cascaded multilevel inverter is a power electronic device developed to synthesize a desired voltage or current waveforms from several levels of dc voltages making use of its reduced switching stress and modular structure. Such inverters have been recognized as very attractive topologies for implementing shunt active power filters in medium and high voltage applications. This paper presents a five-level cascaded multilevel inverter based Shunt Active Power Filter (SAPF) to compensate reactive pow ...
Using the principle of fold-back current limiting, circuitry which permits good chamber voltage regulation during normal operation and still provides the protection of a large series resistance to "soften" the voltage source in case of sparking and other discharges is described. Such circuitry is presently being used in several high energy physics experiments employing proportional wire chambers which require self-destruct protection. Supplementary circuitry which provides a fast crowbar at a pr ...
This paper presents a novel control scheme suitable for high-power high-performance AC power supplies. The performances of the conventional current-regulated voltage-controlled system with bipolar PWM are first analyzed in detail. The proposed control scheme incorporates dual synchronous PWM technique of single-phase full-bridge inverter and multiple feedback loop. Thanks to this scheme, the AC power supply output voltage can maintain high-quality sinewave at low switching frequency and small ou ...
The national power currently standards are not uniform, it can be used for all kinds of transport such as cars, various types of ships, and the vehicle's voltage regulator power inverter using widely. In the field of solar and wind power, the regulator power inverter plays an irreplaceable role. With the voltage regulator power inverter, we can use the direct current (batteries, switching power supply, fuel cells, etc.) into alternating current to provide a stable and reliable power for the elec ...
This paper proposed a Single-Phase 13-level inverter with voltage control method using semiconductor power devices for photovoltaic systems. The multilevel voltage source inverters unique configuration allows them to make high voltages with low harmonics without use of transformers or series associated synchronized switching devices. The general role of the multilevel inverter is to synthesize a desired voltage from several levels of dc voltages for these reason multilevel inverters can simply p ...
Cross regulation of single-inductor multiple-output (SIMO) boost dc/dc converter is usually considered as a key factor that degrades the voltage regulation of individual outputs. Analysis of the cross coupling of a single-switch single-input dual-output (SIDO) boost converter operating in continuous conduction mode (CCM) reveals that it is an automatic current feedback mechanism during converter operation, which, however, can improve steady-state voltage regulation of both outputs. It is possibl ...
DC/DC converters are widely used in power management, conditioning, and control of space power systems. Deep space applications require electronics that withstand cryogenic temperature and meet a stringent radiation tolerance. In this work, the performance of an advanced, radiation-hardened (radhard) commercial DC/DC converter module was investigated at cryogenic temperatures. The converter was investigated in terms of its steady state and dynamic operations. The output voltage regulation, effic ...
This paper deals with the electronic load controller for self exited induction generator using fuzzy logic controller. The self-excited induction generators (SEIGs) are considered to be well suited for generating electricity by means of conventional energy sources and for supplying electrical energy in remote and rural areas. Induction generators have many advantages such as cost, reduced maintenance, rugged, and simple construction, brushless rotor (squirrel cage). A three phase induction gener ...
In order to overcome the difficulties of poor voltage regulation and narrow speed range for the traditional permanent magnet synchronous machine used in the generation system, a parallel-connected open-winding topology is adopted with the inverter in series to one side of the windings and the rectifier to another side. Due to the parallel-connected dc sides of the rectifier and inverter, the zero-sequence current would flow in the windings under the conventional space vector pulse width modulati ...
This paper deals with specific problems encountered when full digital control is applied for the boost-type power factor correction (PFC) converter. The robust performance, voltage regulation and sample frequency of the proposed controller are highlighted. Compared with traditional design, a novel input voltage feed-forward control algorithm is proposed to reduce the closed-loop time constant and output voltage overshoot/drop, which omits a second-order low-pass filter. By synchronizing output v ...
As a critical function in distribution automation, voltage regulation enables the reduction of peak demand and contributes to energy conservation. This paper presents a utility case study of Sioux Valley Energy's voltage regulation strategy for energy conservation. The strategy involves software modeling, voltage setting recommendation and implementation, result analysis, and cost benefit analysis. The utility applies this strategy in its distribution network. Three different substations are con ...
This paper proposes current control method for DCM to achieve same control performance as CCM. The proposed control loop is designed based on the conventional current control loop in CCM. By using only one PI controller and introduction of two correction factors, the proposed control method can control both CCM and DCM current exactly to design values. In this paper, the operation of the proposed control method is confirmed by simulation and experiment. The simulation results of the current resp ...
This paper presents a new method for achieving load voltage regulation and line loss minimization in the loop distribution systems, simultaneously. First, the line loss minimum conditions in the loop distribution systems are presented. Then, load voltage regulation is achieved by using shunt compensation. To achieve these two objectives simultaneously, the Unified Power Flow Controller (UPFC) is used. The UPFC shunt converter is used as a shunt compensator to regulate the load voltage, and the U ...
The digital PWM modulator circuit is capable of varying the duty cycle of the output (PWM) according to the digital input word. A digitally controlled current starved pulse width modulator is described. The current from the power grid to the ring oscillator is controlled by a header circuit. By changing the header current, the pulse width of the switching signal generated at the output of the ring oscillator is dynamically controlled, permitting the duty cycle to vary between 25% and 90%. A duty ...
Low voltage distribution networks have been originally designed to feed loads. However, recently, small dispersed renewable generators, mainly photovoltaics, are being connected to the low voltage grids. This new operational framework represents a challenge to the planning and operation of distribution networks, since the multidimensional stochastic dependence structure of the joint behaviour of the generation and load can be very complex to model. This paper intends to give further insight to t ...
A new internal STATCOM control based on feedback linearization is proposed. The feedback linearization controller is developed without any simplifying assumptions to the STATCOM model. The proposed control is validated on the IEEE 118-bus system with full-order generator and network models as opposed to a small test system. Furthermore, the proposed control is benchmarked against published results. Lastly controllability issues associated with a singularity in the feedback linearization control ...
Doubly fed induction generator (DFIG)-based stand-alone variable-speed constant-frequency systems reported so far cannot supply nonlinear unbalanced load current containing cophasor components. This paper presents three topologies of a stand-alone DFIG which can handle this type of load. The harmonic/imbalance component of the load current in each case is supplied by the stator-side converter. In the first option, a Δ/<i>Y</i> transformer with neutral connection supplies the l ...
This paper presents an implementation of a doubly fed induction generator (DFIG) for a variable speed wind energy conversion system for improving the voltage profile at remote locations. Normally, the wind power generation is at far ends from the load centers. Due to predominant nature of line inductance, the voltage drop is much affected by the reactive power. This voltage control problem is addressed by the coordinated control of both the voltage source converters (VSCs) of DFIG. Control algor ...
A distinctive characteristic of a Microgrid (MG) system is related to the ability of operating autonomously. However, the stability of the system relies in storage and generation availability, providing frequency and voltage regulation. Considering the deployment of distributed storage units in the Low Voltage network and of smart metering infrastructures, this paper presents an online tool for promoting an effective coordination of MG flexible resources in order ensure a secure autonomous opera ...
Because of the increasing share of renewable energies violations of the statuary voltage limits occur more and more often in the German distribution grids. Therefore, distribution system operators take advantage of reactive power support by dispersed generation units for voltage regulation. Commonly, only one standard cosφ(P)-profile is implemented as a control-method for all units to decrease voltage rises. This profile is independent of network characteristics and the point of common co ...
In this paper, the small-signal model of a boundary conduction mode (BCM) boost power factor correction (PFC) converter controlled by a peak control current control IC L6561 is derived. Based on the derived mathematical model, a Type II compensator is thus well designed to make the boost converter exhibits the performances of high power factor and output voltage regulation. Finally, a 300 W prototype of the BCM boost PFC converter with IC L6561 is implemented. The performance of high power facto ...
Nowadays, a large part of the world population lives without access to electricity, principally due to the location, too far from the main grid. Renewable power sources connected in an autonomous local grid are a real opportunity for these communities. These weak electrical grids composed by several microsources, energy storage systems and loads can be considered as islanded microgrids. As it is disconnected from the main grid, the frequency and the voltage of the microgrid have to be controlled ...
Multilevel power electronic converters have gained popularity in high-power applications due to their lower switch voltage stress and modularity. Cascaded H-bridge converters are a promising breed of multilevel converters which generally require several separate dc voltage sources. By utilizing the redundant switching states, it is possible to replace the separate dc voltage sources with capacitors and keep only the one with the highest voltage level. Redundancy in the charge and discharge modes ...
By equipping with the advanced smart meters and two-way communications infrastructure, smart grids, as a key component of future smart cities, are able to improve the energy efficiency and reduce the energy cost through real-time monitoring and customer load scheduling. However, the high penetration of intermittent renewable energy such as solar power may cause frequent overvoltage and undervoltage problems at certain buses, making the load scheduling face new challenges on voltage regulation. I ...
DC-DC converters with high step up gain are acquiring much significance with increase in renewable energy applications. Among them cascade boost derived converters with single active switch are of more interest. In the cascade boost family, quadratic boost converter is the best trade-off when circuit complexity and modulator saturation is considered. Hence, a robust controller design to obtain output voltage regulation in a quadratic boost converter with high dc gain is proposed in this paper. T ...
This paper presents system modeling and nonlinear control design of static compensators (STATCOMs) for fast voltage regulation in the presence of load uncertainty and voltage flicker. A simplified power distribution system is modeled using ideas similar to field oriented control of three phase ac machines. Zero dynamics of the system show that the system is nonminimum phase for certain operating conditions, thus, imposing restrictions on the achievable dynamic response. The control design involv ...
Sustained integration of distributed renewable energy sources, especially photovoltaic generation in low voltage grids, has driven the need to expand grid capacities in recent years. Solutions to find economic justifiable approaches for mains operation in an aging grid environment have become indispensable. This paper highlights the design of a probabilistic simulation environment and several methods of voltage regulation using photovoltaic inverters and a controllable distribution transformer. ...
In this paper, a nonlinearity compensation control is developed and applied for the single-phase Sheppard-Taylor power factor corrector (PFC). Compared to conventional buck, boost or buck-boost PFCs, this topology allows a better current tracking at the AC side, with a relatively reduced voltage at the DC side. Based on the exact linearization of the converter's averaged model, and on the use of a fixed-frequency carrier to generate the Pulse-Width-Modulated (PWM) gate signal, the control system ...
As demand for power increases in rural areas serviced by Single Wire Earth Return (SWER) networks, distribution issues are becoming increasingly evident. Voltage regulation and system capacity concerns are driving utilities toward using smarter compensation devices for network control in an attempt to provide longevity for aging SWER infrastructure. To date, despite increasing complexity in power delivery over SWER, no effective network monitoring solutions have been proposed. This paper examine ...
Distributed Generation has played a very vital role for the improvement of voltage profile nowadays. The application of DG is going to increase in upcoming future as it has a lot of positive impacts such as compatible size, losses reduction, and voltage support. Somehow it has some negative impact also such as voltage regulation, harmonic distortion and conflict with relaying and reclosing. In addition, recently, distributed generation has gained a lot of momentum due to market deregulation, env ...
An increasing adoption of rooftop photovoltaic (PV) generators presents a growing opportunity for the use of their grid-tie inverters to provide reactive power compensation on medium- and low-voltage distribution networks. This paper presents a generalized method based on particle swarm optimization (PSO) for determining how much reactive power is necessary to provide control over the voltage profile of the distribution line for any given operational condition and number of PV connections. The m ...
This paper introduces an impulse excited piezoelectric energy harvesting prototype. The device is aimed at large amplitude, low frequency excitation typical of human body motion. A rolling, external proof mass actuates an array of piezoelectric cantilevers that form a distributed transduction mechanism. After initial deflection, the beams vibrate at their natural frequency. This allows for improved electromechanical coupling and large operational bandwidth. Measurements are presented to include ...
This paper studies a Fuzzy Logic Control Based (FLCB) Shunt Active Filter (SAF) capable of reducing the total harmonics distortion (THD) in Power System (PS). SAF is one of the key controllers in Flexible Alternating Current Transmission System (FACTS) to control the transmission line voltage and can be used in PS to enhance the power transmission capacity and extend the transient stability. In order to improve the power factor, compensate the reactive power and suppress the total harmonic disto ...
A new flyback transformer has been developed with a secondary coil that is divided into several windings which are connected alternately in series with the same number of high-heat resistant, glass-molded diodes has been developed. This new design results in improved voltage enduring properties, facilitates transformer insulation and permits efficient high voltage regulation in dc voltage generation. Overall transformer size and weight are also reduced, which saves space in television receiver s ...