Predictive Current Control for Voltage Source Inverters Considering Dead-Time Effect

This paper proposes a new concept of synthesized voltage vector to address dead-time effect issue for Finite Control Set Model Predictive Control(FCS-MPC)technique.For a voltage source inverter(VSI),dead-time is inevitably inserted between the turn off and turn on instants of power devices to avoid short circuit phenomenon.The influence of dead-time leads to output voltage vector error of three-phase inverters.Furthermore,it will result in computing deviation in cost function,and will deteriorate the performance of the system if not properly dealt with.In this paper,the problem is clearly analyzed,and the solution to this issue is proposed by introducing a synthesized voltage vector.The proposed solution is verified by Hardware-in-the-loop(HiL)test in real time,and results validate the effectiveness of the proposed solution.

Flexible Power Regulation and Limitation of Voltage Source Inverters under Unbalanced Grid Faults

This paper develops a flexible power regulation and limitation strategy of voltage source inverters(VSIs)under unbalanced grid faults.When the classical power theory is used under unbalanced grid faults,the power oscillations and current distortions are inevitable.In the proposed strategy,the extended power theory is introduced to compute the power feedbacks together with the classical power theory.Based on the combination of the classical and extended power theory,the proposed strategy can achieve the sinusoidal current provision and the flexible regulation between three common targets,i.e.,constant active power,balanced current,and constant reactive power.Meanwhile,the proposed strategy is associated with a power limiter,which is capable to keep the currents under the pre-defined threshold and to compute the maximum apparent power for better utilization of the inverter capacity.With this power limiter,the rated inverter capacity is fully used for both the active and reactive power provisions under unbalanced grid faults.Using the proposed power regulation and limitation,the VSI can avoid overcurrent tripping and flexibly regulate its power under unbalanced grid faults.All the conclusions are verified by the real-time hardware-in-loop tests.

Design and Implementation of ANFIS Controller Based Grid Connected Voltage Source Inverters in RTOS Environment

In this manuscript it is proposed and demonstrated that how an ANFIS (Adaptive Neuro Fuzzy Inference System) can be used in the control of a Voltage Source Inverter (VSI) connected to the grid. Volatile changes in the gird parameters rising by its variable demands and other related issues may humiliate the efficiency with which power can be injected into the grid. The system becomes a higher order one with the filters used at the terminal of the Voltage Source Inverter (VSI) along with the parameters of the grid which change from time to time. Single time tuned mathematical controllers like the PID variants are not suitable for such applications. Considering the increased order of the system and the associated non-linearity we have to look out for intelligent controllers. An ANFIS based control is found to be promising;the development and implementation of one such are demonstrated in this paper using the MATLAB SIMULINK platform and through experimental verification using the Reduced Instruction Set Computer (RISC) Microcontroller Advanced RISC Machine (ARM) processor as the central controller for the VSI.

Online Learning Control for Harmonics Reduction Based on Current Controlled Voltage Source Power Inverters

Nonlinear loads in the power distribution system cause non-sinusoidal currents and voltages with harmonic components.Shunt active filters(SAF) with current controlled voltage source inverters(CCVSI) are usually used to obtain balanced and sinusoidal source currents by injecting compensation currents.However,CCVSI with traditional controllers have a limited transient and steady state performance.In this paper,we propose an adaptive dynamic programming(ADP) controller with online learning capability to improve transient response and harmonics.The proposed controller works alongside existing proportional integral(PI) controllers to efficiently track the reference currents in the d-q domain.It can generate adaptive control actions to compensate the PI controller.The proposed system was simulated under different nonlinear(three-phase full wave rectifier) load conditions.The performance of the proposed approach was compared with the traditional approach.We have also included the simulation results without connecting the traditional PI control based power inverter for reference comparison.The online learning based ADP controller not only reduced average total harmonic distortion by 18.41%,but also outperformed traditional PI controllers during transients.

Optimized damping for LCL filters in three-phase voltage source inverters coupled by power grid

The application of LCL filters has become popular for inverters connected to the power grid due to their advantages in harmonic current reductions. However,the power grid in a distribution system is non-ideal, presenting itself as a voltage source with significant impedance. This means that an inverter using an LCL filter may interact with other grid-connected inverters via the nonideal grid. In this paper, damping optimization of LCLfilters to reduce this interaction is studied for a three-phase voltage source inverter(VSI). Simulation results show that resonant oscillation occurs in a distributed power grid, even if the VSI with an LCL filter is well designed for standalone applications. A small-signal analysis is performed to predict this stability problem and to locate the boundary of the instability using an impedance approach. Based on these analytical results, optimized damping of the LCLfilter can be designed. The oscillation phenomena and optimized damping design are verified by simulations and experimental measurements.

Improved Clamped Diode Based Z-Source Network for Three Phase Induction Motor

The 3Φinduction motor is a broadly used electric machine in industrial applications,which plays a vital role in industries because of having plenty of beneficial impacts like low cost and easiness but the problems like decrease in motor speed due to load,high consumption of current and high ripple occurrence of ripples have reduced its preferences.The ultimate objective of this study is to control change in motor speed due to load variations.An improved Trans Z Source Inverter(ΓZSI)with a clamping diode is employed to maintain constant input voltage,reduce ripples and voltage overshoot.To operate induction motor at rated speed,different controllers are used.The conventional Proportional-Inte-gral(PI)controller suffers from high settling time and maximum peak overshoot.To overcome these limitations,Fractional Order Proportional Integral Derivative(FOPID)controller optimized by Gray Wolf Optimization(GWO)technique is employed to provide better performance by eliminating maximum peak overshoot pro-blems.The proposed speed controller provides good dynamic response and controls the induction motor more effectively.The complete setup is implemented in MATLAB Simulation to verify the simulation results.The proposed approach provides optimal performance with high torque and speed along with less steady state error.

Inherently Sinusoidal Single-phase Voltage Source Inverter Based on Modified Cuk Cell

Renewable energy has become important for electricity generation because of the high air pollution associated with conventional fossil-based energy systems.Conventional fossil-based power plants are gradually transitioning by incorporating renewable energy sources,such as photovoltaic(PV)cells.In a PV system,an inverter converts DC power from solar panels to AC power required to serve common electrical loads.A conventional H-bridge inverter topology has several disadvantages,such as the voltage being not sinusoidal,switching the DC voltage and high common-mode voltage.The common-mode voltage can cause a large leaked capacitive current,which can result in undesirable operation in solar power applications.A common solution to this problem is the addition of a large filter to the input or output of an inverter.An inherent sinusoidal voltage source inverter based on a modified Cuk converter as its basic cell,which simultaneously generates a sinusoidal output voltage and a lower common-mode voltage,is proposed.The proposed topology does not require additional input or output filters.Analytical expressions are derived to confirm the operation of the proposed topology.Simulation results confirm the mathematical analysis.A laboratory-scale experiment is performed to verify the proposed inverter.

Improved Interleaved Single-Ended Primary Inductor-Converter forSingle-Phase Grid-Connected System

The generation of electricity based on renewable energy sources,parti-cularly Photovoltaic(PV)system has been greatly increased and it is simply insti-gated for both domestic and commercial uses.The power generated from the PV system is erratic and hence there is a need for an efficient converter to perform the extraction of maximum power.An improved interleaved Single-ended Primary Inductor-Converter(SEPIC)converter is employed in proposed work to extricate most of power from renewable source.This proposed converter minimizes ripples,reduces electromagnetic interference due tofilter elements and the contin-uous input current improves the power output of PV panel.A Crow Search Algo-rithm(CSA)based Proportional Integral(PI)controller is utilized for controlling the converter switches effectively by optimizing the parameters of PI controller.The optimized PI controller reduces ripples present in Direct Current(DC)vol-tage,maintains constant voltage at proposed converter output and reduces over-shoots with minimum settling and rise time.This voltage is given to single phase grid via 1�Voltage Source Inverter(VSI).The command pulses of 1�VSI are produced by simple PI controller.The response of the proposed converter is thus improved with less input current.After implementing CSA based PI the efficiency of proposed converter obtained is 96%and the Total Harmonic Distor-tion(THD)is found to be 2:4%.The dynamics and closed loop operation is designed and modeled using MATLAB Simulink tool and its behavior is performed.

Research of Wavelet Modulation for Single-Phase Three-Level Inverter

The single-phase three-level voltage source inverter based on wavelet modulation(WM) is proposed.The WM technique is based on constructing a nondyadic-type multi-resolution analysis(MRA),which supports sampling continuous-time sinusoidal signals in a nonuniform recurrent manner,and then reconstructing it by using inverter switching actions. In order to further improve the output voltage waveform and reduce harmonic distortion,the wavelet modulation is used to three-level inverter. The high magnitude of fundamental component and significantly reduced harmonic contents of the inverter output voltage can be achieved by using WM in the single-phase three-level voltage source inverter. Furthermore,the WM algorithm is implemented by using only one element government(EV) in DSP. The simulated and experimental results prove the accuracy and feasibility of the WM scheme for single-phase three-level voltage source inverter.

Implementation of PSOANN Optimized PI Control Algorithm for Shunt Active Filter

This paper proposes the optimum controller for shunt active filter(SAF)to mitigate the harmonics and maintain the power quality in the distribution system.It consists of shunt active filter,Voltage Source Inverter(VSI),series inductor and DC bus and nonlinear load.The proposed hybrid approach is a combination of Particle Swarm Optimization(PSO)and Artificial Neural Network(ANN)termed as PSOANN.The PI controller gain parameters of kp and ki are optimized with the help of PSOANN.The PSOANN improves the accuracy of tuning the gain parameters under steady and dynamic load conditions;thereby it reduces the values of THD within the prescribed limits of IEEE 519.The PSO optimizes the dataset of terminal voltage and DC voltage present in shunt active filter for different load condition.The optimized dataset acts as the input for the controller to predict the optimal gain with minimal error and to generate the optimized control signal for the SAF.The proposed methodology is modelled and simulated with the help of MATLAB/Simulink platform and illustrated the few test cases considered for exhibiting the performance of proposed hybrid controller.The experimental results are measured with developed laboratory prototype and compared with the simulation results to validate the effectiveness of the proposed control methodology.

On Designing of the Main Elements of a Hybrid-Electric Vehicle Driving System

The paper deals with the designing of an electric drive system used for hybrid electric vehicles. The driving system is realized with an induction motor and a voltage source inverter. Specifically, the application is for a series hybrid vehicle powered by electric storage batteries charged by solar batteries. In the first part of the paper the designing of the electric storage batteries and of the photoelectric system is presented. In the second part of the paper some aspects regarding the designing of the induction motor are presented. Then some aspects concerning the voltage source inverter designing are exposed.

Distorted Waveform Balancing Using an Artificial Bee Colony (ABC) Based Optimal Control for Mitigating Total Harmonics in Single Phase Inverter

The main objective of this paper is to reduce the total harmonics in a single phase voltage source inverter using Artificial Bee Colony (ABC) optimization technique for critical load applications. Single phase inverter is a non-linear load using power electronic components causing distortions in the load voltage and current wave patterns from the sinusoidal waveforms due to harmonics. The mapping state space model for a full bridge voltage source inverter was developed using output load resistance. An optimal ABC technique has been designed and optimized values are estimated using a full bridge voltage controlled inverter using Proportional Integral Algorithm. The MATLAB/SIMULINK tool and Experimental setup were implemented and their THD values were estimated. Also this ABC scheme is compared with the previous results such as PI Algorithm, Fuzzy logic controller and Neuro-fuzzy controllers. From the simulation and experimental results using ABC algorithm, it is observed that the total harmonics are mitigated considerably compared to previous results with respect to the power quality standards such as IEEE-519 and IEC 61000.

Continuous Mixed p-norm Control Scheme with Reweighted L_(0) norm Variable Step Size for Mitigating Power Quality Problems of Grid Coupled Solar PV Systems

In this paper,the performance of a two-stage three-phase grid coupled solar photovoltaic generating system(SPVGS)is analyzed by using a novel reweighted Lo norm variable step size continuous mixed p-norm(RLo-VSSCMPN)of a voltage source inverter(VSI)control scheme.The efficacy of the system is determined by considering unbalanced grid voltage,DC offset,voltage sag and swell,unbalanced load and variations in solar insolation.RLo-VSSCMPN is used for inverter control and it ex-tracts fundamental components of load current for generating the reference grid current with a faster convergence rate and lesser steady state oscillations.With the proposed control,harmonics in the grid current follows the IEEE-519 norm and the performance is also satisfactory under varying environmental/load conditions.The power generated from SPvGS is transferred optimally using a DC-DC boost converter utilizing the incremental conductance(INC)maximum power point technique.The proposed system is simulated using MATLAB/Simulink 2018a and test results are verified experimentally using dSPACE1202 in the laboratory to ensure the validity of a novel proposed robust RLo-VSSCMPN.Index Terms-INC maximum power point tracker,power quality,reweighted LoVSSCMPN algorithm,solar PV generating system,total harmonic distortion,voltage source inverter.

A simple digital control algorithm for three phase shunt active filter： simulation and experimentation

A novel and simple ifrea! control algorithm using digital signal processor （DSP） has been proposed and realized for a three phase shunt active filter （SAF）. The simulation and prototype construction of SAF is conducted to compensate the reactive power and harmonics in a distribution system. The major feature of the proposed ifreal algorithm is that it does not require unit vector templates and any transformations for the reference current genera- tion of SAF. This reduces the computational complexity and makes the control flexible and faster. The simulation is conducted in MATLAB/SIMULINK while DSP TMS320LF2407 is employed in the digital implementation of hysteresis current control （HCC） for experimentation. The hardware results correlate with the simulation results in reducing the total harmonic distortion （THD） of the source current and achieving unity power factor.

Derated Mode of Power Generation in PV System Using Modified Perturb and Observe MPPT Algorithm

In a grid-integrated photovoltaic system(GIPVS),there exist issues such as surplus active power and inadequate performance of maximum power point tracking(MPPT).A surplus active power causes the overvoltage problem at the point of common coupling in low-or medium-voltage grid during the peak hours of power generation.Additionally,the inadequate performance of the MPPT algorithm results in power loss due to high settling time during the sudden change of irradiance.Therefore,to solve the surplus power problem,the curtailment of active power is suggested with improved MPPT algorithm under variable irradiance conditions.In this paper,a derated power generation mode(DPGM)control strategy is presented for the curtailment of active power.Additionally,a drift-free(named as modified)perturb and observe(P&O)technique is also proposed to improve the performance of the MPPT algorithm.Consequently,the DPGM control scheme with the intermediate boost converter shaves the surplus active power during the peak hours of power generation.Furthermore,the modified MPPT algorithm deals with the fluctuation of irradiance during non-peak hours.Thus,the proposed control scheme delivers in a more efficient system during the peak hours of power generation.In addition,it reduces the power loss and settling time during the change of irradiance for non-peak hours.Based on the proposed control scheme,a 30 kW system has been simulated in MATLAB/Simulink using Simpower tools under different environmental conditions.