LC Compensator Research Articles

Design and Analysis LCCL–LC Compensation for Electric Vehicle Systems

Design and Analysis LCCL–LC Compensation for Electric Vehicle Systems

A Constant Output Capacitive Wireless Power Transfer System Based on Parity-Time Symmetric

In existing capacitive wireless power transfer (CPT) systems, the coupling capacitance of the traditional couplers is usually small, which will lead to a significant decrease in the power transfer capability when the transfer distance increases. Thus, it is a big challenge to achieve stable output power and constant transfer efficiency under different coupling capacitance. In this work, the circuit model of the CPT system with double-side LC compensation network is established firstly. Then, based on the parity-time (PT) symmetric theory, a primary-side control strategy is presented to achieve stable output power and constant high transfer efficiency when the coupling capacitance changes. Finally, the experimental results show that when the insertion depth of the stack array coupler changes from 60 to 180 mm, the output power of the proposed CPT prototype is almost stable at 25W, and the transfer efficiency is kept at around 88%, which verifies the feasibility and effectiveness of the proposed design.

Optimal switching scheme of thyristor-controlled LC compensator to enhance the power quality in unbalance distribution system

Optimal switching scheme of thyristor-controlled LC compensator to enhance the power quality in unbalance distribution system

AN OPTIMIZED DESIGN MODELLING OF A NEURAL NETWORK BASED GREEN HOUSE MANAGEMENT SYSTEM USING SOLAR AND RECTIFYING ANTENNA

The renewable energy resources are widely used in various real time applications, which utilized the solar, wind, fuel cell, etc. From this, the energy management and controlling strategy improves the results. The conventional approach uses Quantum Tunneling PSO for optimization and it is managed with various utility on power grid system. The work utilized the solar and EM waves for energy management scheme and it utilized the controlling parameter by optimization algorithm. The drawback of conventional method is that, the hybrid system utilization and switching is performed with random selection and it not capable for hybrid resources of multiple array functioning. The proposed research work performed with the solar with MPPT tracking and EM with rectenna are utilized and with the help of neural network model, the PV and RF signal generations are stored as array and based on the switching duty cycle from the function of proposed particle swarm optimization, the boost converter act to provide the supply to grid. Through the inverter control, the model fed with the grid, which uses PI controlling with PWM signal generation. Based on the demand and grid utility the LC compensation improves the boost converter performance. The PV and RF signal generation utilized on the continuous utility and obtains the demand free grid circuit. By comparing with the proposed and existing approach, the proposed greenhouse management model obtains the better result. Overall simulink model is done with MATLAB 2018a. Keywords- PV module; EM waves; Rectenna; Proposed PSO; Feed Forward neural network; PI controller and grid utility;

Cascaded Boost‐Class‐E for rotary capacitive power transfer system

This paper presents a capacitive power transfer (CPT) system design for low-power rotary applications. The aim of a rotary CPT system is to be free of power cables so it can achieve 360 degrees of free rotation, while remaining simple and easy to clean. In this work, a class-E high-frequency inverter with second-order LC compensation is proposed to drive the rotary CPT system. An LC compensation circuit is applied on both stationary and rotating sides in order to maximise the power transfer by increasing the voltage across the coupling plates. By implementing the proposed technique, the Class-E LCCL rotary CPT system that is efficient and less sensitive to load variations can be achieved. A Boost converter is also proposed here to provide input impedance matching and tune the input power of the Class-E LCCL rotary CPT system. A 10 W multiple plate rotary CPT prototype based on cascaded Boost- Class E LCCL is designed and implemented to demonstrate efficient wireless power transfer (WPT) across the rotating load. The results reveal >76% power transfer efficiency is successfully achieved at 1 MHz operating frequency and with 7.67 W output power.

Wide Design Range of Constant Output Current Using Double-Sided LC Compensation Circuits for Inductive-Power-Transfer Applications

Inductive-power-transfer (IPT) converters should desirably achieve nearly zero reactive circulating power, soft switching of power devices and load-independent constant output voltage or current with optimized transfer efficiency, and lowest component ratings. However, the load-independent output characteristic is dependent on IPT transformer parameters and their compensation. The space-constrained IPT transformer restricts the design of the low-order resonant circuit compensated IPT converter, making the IPT converter hard to optimize. This paper will analyze conditions under which any extra design freedom can be allowed for a double-sided LC compensation circuit in order to achieve load-independent output and zero reactive power input. A detailed analysis is given for the double-sided LC compensation achieving zero reactive power input and constant current output, without being constrained by the transformer parameters. Design conditions of the compensation circuit parameters for achieving these two properties are derived. A complementary LC - CC compensated IPT converter is further proposed to extend the output current amplitude limitation of the double-sided LC compensated IPT converter. Finally, the prototypes of the IPT converters are constructed to verify the design flexibility of the proposed double-sided LC compensation circuit for achieving the multiple objectives.

Design of a Thyristor Controlled <italic>LC</italic> Compensator for Dynamic Reactive Power Compensation in Smart Grid

This paper presents a thyristor controlled LC (TCLC) compensator for dynamic reactive power compensation in a smart grid system. Compared with the traditional static var compensators like a fixed capacitor-thyristor controlled reactor (FC-TCR) which generates low order harmonic currents, the proposed TCLC can significantly mitigate the injection of harmonic currents. In this paper, the design of the TCLC parameters is investigated with the considerations of its reactive power compensation range and harmonic currents rejection. And a control method based on the generalized instantaneous reactive power theory is proposed. Moreover, representative simulation and experimental results of the proposed three-phase three-wire TCLC are presented to show its effectiveness in dynamic reactive power compensation in comparison with the traditional FC-TCR and parallel combination of FC-TCR and passive power filter.

Study of genetic algorithm performance through design of multi-step LC compensator for time-varying nonlinear loads

Genetic algorithm (GA) is a search mechanism simulating the natural selection and population genetics. The performance of GA is related to processing time and the number of generations required for convergence and the convergence itself. This article studies how the performance of GA is affected by choosing its parameters and implementation techniques through designing the multi-step LC based on performance criteria; maximizing the power factor (PF), minimizing the transmission loss (TL), or minimizing the voltage total harmonic distortion (VTHD). The multi-step LC compensator consists of switchable units thus assuming that a single unit is not sufficient to ensure satisfactory results. GA is used to estimate that steps while holding the performance quantities at the corresponding desired values and constraining the compensator values which would create resonance. The contribution of the proposed procedure is demonstrated in examples taken from previous publications. Finally, simulated results show the performance of GA is widely affected by choosing its parameters and implementation techniques and hence it could be improved.

Design of multi-step LC compensator for time-varying nonlinear loads based on genetic algorithm

Summary This article presents a method to consider the probabilistic nature of load impedance and harmonic currents by designing a multi-step inductive-capacitive (LC) compensator consisting of switchable units thus assuming that a single unit is not sufficient to ensure satisfactory results. The proposed algorithm divides the time period into sub-regions according to the scheduled number of switchable units over which the multi-step LC compensator is optimized through different performance criteria; maximizing the power factor (PF), minimizing the transmission loss (TL) or minimizing the voltage total harmonic distortion (VTHD); as objective function resulting in lower variance, and hence, the more accurate expectation is obtained. Genetic algorithm (GA) is used to estimate that steps while holding the performance quantities at the corresponding desired values and constraining the compensator values which would create resonance. Also, the manufacturer's standard values for power shunt capacitors with/without equal steps are considered. GA is a search mechanism based on the principle of natural selection and population genetics. The contribution of the proposed procedure is demonstrated in examples taken from previous publications. Finally, simulated results show that the multi-step LC compensator provides a considerable improvement in the performance in case of the probabilistic condition. Copyright © 2016 John Wiley & Sons, Ltd.

Economic aspects for multi‐step LC compensator with uncertain load characteristics using genetic algorithm

This study presents a method to consider the probabilistic nature of load impedance and harmonic currents by converting the conventional inductive–capacitive (LC) compensator into a multi-step type consisting of switchable units thus assuming that a single unit is not sufficient to ensure satisfactory results. The compensator steps are optimised based on economic criteria; minimising cost and maximising saving; in addition to cost-constrained performance criteria; maximising the power factor, minimising the transmission loss or minimising the voltage total harmonic distortion. The compensator values which would create resonance are constrained. Also the manufacturer's standard values for power shunt capacitors are considered. Genetic algorithm (GA) is used in the optimisation process plus numerical iterative method. GA is a search mechanism based on the principle of natural selection and population genetics. The contribution of the proposed procedure is demonstrated in examples taken from previous publications. Finally, simulated results show that the multi-step LC compensator provides a considerable improvement in the economics in case of probabilistic condition.

Voltage Harmonic Reduction for Randomly Time-Varying Source Characteristics and Voltage Harmonics

Potential applications of probabilistic modeling of current and voltage harmonics concern many aspects of power system engineering as accurate prediction of power system harmonic behavior provides important information to utility companies and equipment designers. In this paper, a method of reducing the expected value of the total voltage harmonic distortion for a specified range of source impedance values at different buses by using LC compensators, where it is desired to maintain a given power factor at a specified value, is presented. The criterion is based on mean value estimation of source and load characteristics, which are enabled by sampling measurements performed on the examined electrical plant as well as statistical analysis.

Effect of time variation of system impedance and voltage harmonics on LC compensation for nonlinear loads

The goal of this paper is to determine the values of the optimum switchable LC compensators for maximum power factor or minimum transmission loss for nonlinear loads where the source harmonic voltages, load impedance and the Thevenin impedance are time varying. All the source harmonic voltages follow the same pattern. Also, a simple time variation for the Thevenin impedance is assumed. A significant part of the load consists from induction motors. The performance of the obtained compensator is discussed by means of numerical examples.

THE IMPACT OF SHUNT COMPENSATION ON TOTAL HARMONIC DISTORTION

The objective of connecting shunt compensation at nonlinear load terminals is to reduce the displacement angle between the supply voltage vector and the fundamental supply current vector, thereby increasing the power factor. The important feature, however, is the effect on the total harmonic distortion of either voltage or current. This article considers this effect, with ideal supply, and also where the supply impedance exists. The authors also present an algorithm for optimizing LC compensator sizing with nonsinusoidal substation voltages, such that total harmonic distortion will be minimum, and the power factor lies within prescribed values.

LC Compensation for Nonlinear Loads Taking Into Account Cost Constraints

An optimization method for the proper selection of the LC compensator values taking into account cost constraints is described for nonlinear loads. The solution will be obtained with an optimization algorithm based on the reduced gradient technique, which will locate maximum power factors by searching along the constant–cost power factor ridges for the point where the gradient of the transmission loss is zero. It is assumed that both the equivalent source and load are considered to generate harmonics. Also, it is assumed that the load harmonics are not sufficiently serious to suggest tuned filters, but when combined with source harmonics, the use of a pure capacitive compensator would degrade power factor and overload equipment. Consequently, a LC compensator is selected.

The Most Economical Power Factor Correction According to Tariff Structures in Egypt

A method of applying power-factor (PF) correction capacitors is discussed based on net savings maximization according to Egyptian's Tariff. Test results from examples taken from existing publications are presented. The purpose of this application technique is to utilize existing electrical distribution equipment in the installation of very large values of PF correction capacitors. It is concluded that LC compensators can be installed, thus providing maximum benefits from penalty elimination, system losses reduction, release of system transformer capacity, and minimum switching transients. Paybacks of less than one year can be expected.

Cost-effective applications of power factor correction for nonlinear loads

The objective of this paper is to propose a new approach for designing passive LC compensators by using the penalty function method as an optimization tool. The performance of the cost-effective passive LC compensator for a constant load depends on the appropriate inductor and capacitor selection. Several design methods are reviewed and a novel design methodology is proposed in this paper. By using the proposed method, the designer can quickly find appropriate parameter values to meet the desired circuit performance. Simulated results show that an appropriate combination of the inductor and capacitor selected by the proposed method can meet the desired power-quality requirement. Different cases of design examples are shown in this paper to verify the performance of the proposed design methodology.

Harmonic adjusted power factor correction in nonsinusoidal environment

An optimisation criterion is presented which allows proper calculation of optimum fixed LC combination in a power factor installation. Optimisation maximises the harmonic-adjusted power factor. In the paper, it is assumed that the load harmonics are not sufficiently serious to suggest tuned filters, but, when combined with source harmonics, the use of a pure capacitive compensator would degrade power factor and overload equipment. Consequently, an LC compensator is selected. It appears that this approach is practical, justifiable, compatible with existing rate structures and relatively easy to implement. The contribution of the developed method is demonstrated in examples taken from previous publications.

LC Compensators Based on Transmission Loss Minimization for Nonlinear Loads

This paper presents a method employing the penalty function search algorithm to determine the LC compensator value for the optimal power factor correction in nonsinusoidal systems. The objective of the proposed method is to minimize the transmission loss while the power factor and efficiency are taken as constraints and utilized in order to solve the multiobjective optimization problem by transforming it into a single objective one. Examples show that the load nonlinearity can have a significant impact on optimal compensator sizes.

LC Compensators for Power FactorCorrection of Nonlinear Loads

A method is presented for finding the optimum fixed LC compensator for power factor correction of nonlinear loads where both source voltage and load current harmonics are present. The LC combination is selected because pure capacitive capacitors alone would not sufficiently correct the power factor. Optimization minimizes the transmission loss, maximizes the power factor, and maximizes the efficiency. The performance of the obtained compensator is discussed by means of numerical examples.

Practical Considerations Regarding Power Factor for Nonlinear Loads

The choice of LC compensator may be constrained by the availability of manufacturers units. To account for this, the capacitor values are chosen from among standard values and for each value the transmission losses is minimized, or power factor is maximized, or transmission efficiency is maximized. The global minimum or maximum is obtained by scanning all local minims or maxims. The performance of the obtained compensator is discussed by means of numerical examples.