Switching Pulses Research Articles

Experimental validation of non-dual adaptive controller based DSTATCOM for power quality enhancement

Abstract In this manuscript, a new control approach is counselled for DSTATCOM to resolve power quality (PQ) related issues. The Non-dual Adaptive Controller (NDAC) is employed with DSTATCOM to enhance the performance in terms of stability. The DSTATCOM is the constituent of voltage source inverter shunt DC-capacitor. A hysteresis block is employed for switching pulse triggering. The counselled scheme is a new method of shunt compensation and offers superior performance, for the lower frequency band in comparision with traditional strategies. Now-a-days we are dealing with huge nonlinear loads which draws non sinusoidal currents and also they generate large amount of harmonics. There are various advantages of using this new modified adaptive controllers over the tradition controllers. We are going to compare the performance of this new counselled controllers performance with the existing one in this literature. This new controller is initially simulated over MATLAB 2016 and then the efficacy of the counselled control approach (NDAC) is investigated using Laboratory prototype. Hardware setup is then authenticated through prototype with the help of dSPACE 1104. The execution reflects wide variation in the performances of both the controllers and also shows the supremacy of Non-dual adaptive controllers in terms of various aspects like harmonic current reduction, reduction in Total harmonic distortions during load dynamics.

High spatiotemporal resolved imaging of ultrafast control of nondiffracting surface plasmon polaritons

Abstract Nondiffracting Bessel surface plasmon polariton (SPP) beams, which have unique self-healing, non-divergence, and linear transmission properties, have charming applications in plasmonic devices and on-chip interconnection circuits. Here we first realize, to the best of our knowledge, the ultrafast control and imaging of the Bessel SPP pulse on the nano-femto scale in the experiment. We demonstrate ultrafast control of Bessel SPP pulse switching by controlling the instantaneous polarization state of the excitation light. Moreover, this variation process is directly mapped on the nano-femto scale by time-resolved two-color photoemission electron microscopy. The results are well reproduced by the finite-difference time-domain (FDTD) method. The current study of ultrafast control and spatiotemporally imaging the switching process establishes an experimental paradigm for revealing the complex mechanisms in ultrafast control of nondiffracting SPP and are useful for developing high-speed, highly-integrated nanophotonic devices, and on-chip circuits.

PWM-Current Source Converter Based on IGCT-in-Series for DC Buck and Constant-Current Application: Topology, Design, and Experiment

PWM-current source converter (CSC) based on IGCT-in-series has the advantages in efficiency, reliability, cost, and controllability. It is a promising choice to replace silicon-controlled rectifier in dc buck and constant-current application, as well as to use in power transmission. This article firstly presents the series-IGCT-based CSC topology according to the IGCT device and CSC operation characteristics. On the basis of traditional CSC topology, di/dt-limitation inductor, absorption circuit and voltage sharing circuit are set. Secondly, the commutation process of series-IGCT-based CSC in each stage of one ac period is analyzed to obtain the coupling model between overvoltage on device and converter parameters. Furthermore, a prototype of 10kV, 1kA series-IGCT-based CSC for transmission line deicing is designed in both parameter and structure. Finally, pulse switching and power-cycling experiments of implemented prototype are carried out. The results verify that with designed parameters, overvoltage on devices is within a save range, and voltage unevenness among six units in series can be limited to 6.5%. Moreover, the prototype shows stability and reliability during long-term power-cycle operation, definitely verifying the feasibility of proposed series-IGCT-based CSC. Compared with IGBT, loss power of IGCT scheme is more than 10% lower, and reach the efficiency of 98.7%.

A Miniaturized Sealed-Off Double-Gap Pseudospark Switch for High Power and High Repetition Rate Pulsed Discharge Applications

Pulsed power systems can deliver high peak power in a micro/nano-second timescale to various loads in scientific and industrial applications, whose performances are significantly influenced by the pulsed discharge switch. This paper presents the development and comprehensive tests of a miniaturized sealed-off pseudospark switch. The structure of double-gap and multi-channel is adopted to achieve the high hold-off voltage and high current capacity. In single pulse tests, the influence of pressure in the switch is analyzed. As the pressure increases, values of multiple parameters decrease, like self-breakdown voltage, trigger delay, and voltage dropping time. In a wide pressure range, trigger jitter is below 3 ns, and the minimum is < 1 ns. At low pressure, the transient voltage across two gaps becomes inconsistent, and two types of current quenching are observed, which are related to processes occurring on cathode surface. In repetitive pulse tests, the direct repetitive operation is up to 3.5 kHz while higher repetition rate is limited by the trigger system. In double-pulse tests, the maximum repetition rate can be higher than 8 kHz for 40 kV pulsed voltage. Meanwhile, the insulation recovery speed is higher at lower pressure, and as the time delay between two pulses increases, the second pulse breakdown voltage increases nonlinearly. In high current tests, the switch is also used in metal wire explosion experiments and operates at the condition of 30 kV/40 kA for more than 104 shots without performance degradation. Further lifetime tests point out that the switch can work for >106 shots stably at moderate current. Experiments prove that the designed switch has superior performances including high hold-off voltage (>50 kV), low jitter (<1 ns), high repetition rate (>3.5 kHz), high peak current (>40 kA), long lifetime (>106 shots) and miniaturized size.

Analysis and Design of an Integrated Bidirectional Three-Phase AC–DC Resonant Converter

This paper proposes a novel isolated bidirectional AC-DC converter where the front end and primary side of DC-DC isolated converter are merged giving rise to 25&#x0025; fewer devices. Owing to the integrated topology the devices of the proposed converter are naturally soft switched and the size of the filtering components in the AC-DC stage is reduced compared to a low frequency hard switched AC-DC stage. A Space Vector Modulation (SVM) and control technique is proposed for generating switching pulses for DC link voltage control and bidirectional power transfer. A design optimization technique is proposed to mathematically determine the switching frequency of the converter and subsequently, the resonant tank parameters based on the operating conditions, topology, modulation, and the Wide Band Gap (WBG) Silicon Carbide (SiC) device characteristics. The proposed converter and its design approach are validated through prototyping for a scaled-down bidirectional charger for warehouse Electric Vehicles (EVs), and experimental results from two test cases, one with the actual grid with an input ac line (<i>i.e.,</i> 208&#x00A0;V) voltage and second with an AC power supply of input line (<i>i.e.,</i> 400&#x00A0;V) voltage. The former is tested for a peak power rating of 2.5&#x00A0;kW and the later is tested for a 5&#x00A0;kW output power. The switching frequency from the proposed optimization method is determined to be around 130&#x00A0;kHz for both cases. Peak efficiency of 95.3&#x0025; is achieved. The battery voltage varies from 350-600&#x00A0;V.

An Adaptive Estimator Based Sliding Mode Control of Nonisolated Single-Input Double-Output Cuk Converter

This article presents an adaptive estimator based sliding mode control (AESMC) for a single-input dual-output (SIDO) converter used in applications requiring multiple regulated output voltages. The proposed SIDO converter is synthesized from the conventional Cuk converter by inserting an additional switch and inductor. However, the coupled capacitor present in the proposed converter topology leads to cross-coupling (CC) and cross-regulation (CR) issues, resulting in the instability of the converter. Furthermore, these issues increase the parameter design and control complexity of the converter. Therefore, this article proposes AESMC to address the CC and CR issues present in the converter. The adaptive estimator of AESMC facilitates the design of adaptive law for effectively estimating the system disturbances. Then, based on the estimated parameters, the input of the SMC is designed to generate switching pulses. Furthermore, the effectiveness of the AESMC in eliminating CC and CR effects is validated by comparing the results obtained with the decoupler+PI controller. Moreover, the system stability analysis with the proposed control technique is presented by considering the Lyapunov direct method. The effectiveness of the proposed control algorithm is evaluated in MATLAB/Simulink, and the obtained results are validated in a hardware prototype developed in the laboratory.

Modular three phase asymmetrical cascaded multilevel inverter with lower number of switches

ABSTRACT This paper introduces a modular circuit for three-phase asymmetrical multilevel inverter, which is composed of series basic unit cells. It requires fewer number of switches as compared to conventional MLI circuits. Carrier-based pulse width modulation scheme is used to generate switching pulses circuit switches. The proposed circuit is compared with conventional MLI circuit. In order to verify the superiority of proposed circuit, a single phase 4-level inverter and three phase 7-level inverter are simulated in MATLAB/Simulink environment and hardware porotype is also demonstrated using dSPACE 1104 real-time controller.

Modified Hybrid PSO Algorithm for Efficient Control of the Matrix Converter-Fed Electrical Drive System

Advanced power converters are being developed due to the latest developments in power electronics switches. The matrix converter (MC) assessment is the product of this drastic growth. MC is a bidirectional power flow device with a single-step energy conversion mechanism that operates at variable voltage and frequency. The main drawback of MC is the presence of harmonics due to power electronic device switching. A lot of research has been done to decrease the harmonics content present in the MC, but it is restricted to a certain level only. To overcome this limit, the harmonics are minimized in the MC by incorporating soft computing controllers. This article presents particle swarm optimization (PSO), modified PSO (MPSO), and modified hybrid PSO (MHPSO) based controllers for different loads. The proposed MC with a soft computing controller reduces the harmonics by selecting suitable switching pulses for every sample. The simulations are made using the MATLAB/Simulink environment. The results of the proposed MHPSO controller reduce the THD value from 8.654 with a PSO approach to 7.536 in the presence of nonlinear loads.

A Coyote Optimization-Based Residual Attention Echo State Reactive Controller for Improving Power Quality in Grid-PV Systems

Improving the power quality and reactive injection capability of grid-PV systems represent the most demanding and crucial tasks in power systems. In the conventional works, many types of converters and regulating approaches have been designed for this goal. The multi-level inverter (MLI) is the best solution for grid-PV systems since it helps to improve power quality while reducing losses. However, the existing works face the key problems of the complex system model, increased components utilization, computational burden, presence of harmonics, and high switching frequency. Therefore, the proposed work aims to develop novel and advanced controlling techniques for improving the reactive power compensation ability and power quality of grid-PV systems. The original contribution of this paper is to implement an advanced soft-computing methodologies for developing the controlling mechanisms. At first, an ATOM search optimization (AOS) based MPPT controlling technique is used to extract the maximum electrical energy from the PV panels under changing climatic situations. Then, the output voltage of PV is effectively regulated with the help of a non-isolated high voltage gain DC-DC converter, which also supports the reduction of the switching loss and frequencies. In order to generate the switching pulses for operating the converter, a novel coyote optimized converter control (COCC) mechanism is developed in this work. Moreover, a residual attention echo state reactive controller (RaERC) is implemented for generating the controlling signals to actuate the switching components of the nine-level inverter. This kind of controlling mechanism could highly improve the power quality of grid system with less processing time. For assessment, the simulation and comparison results of the proposed controlling mechanisms are validated and tested using various parameters.

An Enhancement of Power Quality With Efficient Active Power Transfer Capability in a PV–BSS-Fed UAPF for Microgrid Realization

This article investigates the enhancement of power quality with an efficient active power transfer capability in a universal active power filter (UAPF) integrated with a photovoltaic (PV) and battery storage system (BSS). The UAPF operates as a bidirectional interface between the PV–BSS and point of interconnection for microgrid realization. A new control strategy is proposed to extract fast and accurate voltage and current reference signals to operate the system in a desired manner. Here, the extraction of load voltages and calculation of load and reference powers are used to generate the reference signals, thereby comparing with actual signals with hysteresis controller to produce switching pulses of converters. As a result, the shunt and series converters form a robust system by acting as a current-controlled voltage source and voltage-controlled current source, respectively. It eliminates the need for adaptive filters and low-pass filters to extract the fundamental component of the load current. Furthermore, it increases the conversion efficiency of converters and improves the static and dynamic performance of the system. The proposed system is developed with a 1-kVA prototype laboratory setup using a field-programmable gate array controller and extensively tested with various test conditions such as grid voltage fluctuations, nonlinear and imbalanced load, and change in irradiance.

Harmonic Mitigation in a Hybrid Power System Integrated Shunt Active Power Filter Employing FLC and an Adaptive Current Control Technique

The main objective of this study is to mitigate current harmonic issues in hybrid renewable energy systems based on solar photovoltaic (SPV) and wind energy distribution. This is achieved with the help of a suitable controller-based shunt active power filter (SAPF). The SAPF is designed using a modified synchronous reference frame (MSRF) to reference current generation, an adaptive hysteresis current controller (AHCC) for switching pulse generation, and a fuzzy logic controller (FLC) for DC-link voltage regulation. The results of the proposed SAPF model developed in MATLAB/Simulink, show that the filter performs remarkably well in suppressing harmonics under different loading conditions. It is capable of fast corrective action under dynamic conditions and outperforms previous methods in terms of harmonic mitigation and dc-link voltage stabilization. The control techniques are compared on the basis of parameters such as harmonic compensation and dc-link voltage ripple reduction capability under changing load conditions. The results obtained through simulation represent the validity of the filter performance.

FPGA Based Integrated Control of Brushless DC Motor for Renewable Energy Storage System

To reduce air pollution and global warming, renewable energy technologies may generate power. Wind, solar PV, and fuel cell energy are the primary sources. Solar PV system-powered brushless direct current motor (BLDC) drives are used in the automobile industry due to their importance. In this study, Sheppard–Taylor (S-T) converter and Pulse Width Modulated (PWM) Inverter-fed BLDC provide steady voltage across the BLDC motor drive independent of solar PV system power output. When renewable energy is scarce, the proposed battery-supercapacitor hybrid energy storage system (BS-HESS) provides electricity. S-T converters may be used for load matching and power processing to create energy-efficient systems and stabilize PV panel output voltage. The variable step size open circuit voltage-Maximum Power Point Tracking (VSSOCV-MPPT) technique in S-T converter switching pulses extracts maximum power from the solar PV system. This study considers the PVSWPS control function as a Port-Controlled Hamiltonian (PCH) system to continue rural growth and reduce the greatest demand and load. MATLAB/Simulink software simulates the system’s performance, and FPGA controllers validate the controller’s real-time performance.

Torque control-based induction motor speed control using Anticipating Power Impulse Technique

In this model, the induction motor speed control is based on torque control drive analysis of the output power using Anticipating Power Impulse Technique (APIT). Induction motors are used in various applications; this is a model of a motor used in constant speed applications. Vibrations and singularities are eliminated with the sliding mode control of conventional terminals. In this method, the reference state is determined in a systematic manner so that the maximum torque per ampere and flux limiting operation and the reference torque tracking can be determined. The difficulty of a controller driver is choosing a switch with the proper control scheme to achieve dynamic and steady-state response speed requirements and the proposed method is completely varied from the conventional model. An Anticipating Power Impulse Technique (APIT) is the proposed system for the induction motor drive control; it is also applied to the speed control of the motor. The system presented here analyses motor current and rotor position, which helps to obtain a suitable switching pulse diver circuit, because of low switching loss speed control. In this system, MATLAB software is used to develop control circuit simulations. It is expected that the simulation output will reduce the torque ripple verified by experiments and Anticipating Power Impulse Technique (APIT), giving the system output excellent stability.

A Novel Control Scheme Using UAPF in an Integrated PV Grid-Tied System

This article investigates the photovoltaic fed universal active power filter (PV-UAPF) system for enhancing power quality indices. A novel comb filter together with second-order generalized integrator (CFSOGI) based instantaneous power balance theory with power angle (IPBTPA) control scheme is implemented. Under distorted or adverse grid conditions, the CFSOGI effectively extracts the phase angle, frequency, and fundamental positive and negative sequence components (FPNSC) to overcome the limitations of adaptive notch filters. Here, a comb filter constitutes a cluster/group of zeros at multiple harmonic frequencies to achieve notch peaks thereby providing superior harmonic rejection ability. Whereas, IPBTPA generates the reference signals to operate the system at dual compensation strategy with or without solar PV. The power angle is used to extract the desired load voltages under grid voltage fluctuations thereby reducing the burden on the shunt converter. Moreover, the hysteresis controller generates the switching pulses based on the calculation of reference and load powers which improves the dynamic performance by maintaining system power balance and effective DC voltage regulation. Besides, reactive power compensation, suppression of harmonic currents and mitigation of grid voltage fluctuations is also carried out to strengthen the system further. The system is also tested in grid voltage interruption for islanding mode to realize a microgrid system. The overall system performance is also validated using simulation and in a real-time experimental set-up, and results are demonstrated under various conditions.

Hybrid bat–grasshopper and bat–modified multiverse optimization for solar photovoltaics maximum power generation

A hybrid BAT with Grasshopper (GH) algorithm and BAT-MMVO (Modified Multiverse Optimization) are exhibited for harvesting maximum power from photovoltaics (PV) using the Xilinx System Generator (XSG) implanted controller. Using a hybrid BAT-GH and BAT-MMVO algorithm, the proposed implanted controller finds the best switching pulse for the boost converter. The implanted controller, switching schemes, and the Photovoltaic (PV) supported boost converter were built using the XSG domain. The hardware implementation of the best two cases were done using a microcontroller in a smaller scale. This aims to gather the maximum amount of power by a PV array for solar irradiation and cell temperature under varied environmental situations. The PV structure in the XSG domain is used to construct the system model for prediction. The major emphasis of this work is to keep the difference of actual power and reference power as minimum. Finally, the implanted controller's performance is compared to that of other existing hybrid controllers. The performance of the proposed algorithm is found to yield good results in terms of power extraction. The theoretical and experimental results are presented. The computational efforts for the implementation of the algorithm are found to be less complex when compared to other existing methods.

An improved robust coupled sliding mode control strategy for solar photovoltaic‐based single‐phase inverters

SummarySolar photovoltaic (SPV)‐based single‐phase inverters are universally accepted and commercially utilized renewable power converter system. Generally, the magnitude of the inverter output is perturbed on load variations, and the intermediate DC‐DC boost converter output is perturbed because of the solar availability. The main intermediary component is the DC‐Link capacitor. The regulation of DC‐Link voltage is the key factor in maintaining the stability of the system with bilateral power converters. In the existing methods, individual Sliding Mode Control (SMC) are used to maintain the stability of the converters independently. However, the individual SMC's do not have any corelated control to address the common problem of DC‐Link voltage regulation. This paper proposes an alternative solution with Coupled SMC (CSMC) to address the problem of regulating the DC‐Link voltage. Both the Boost‐SMC and Inverter‐SMC are individually developed and controlled in a unified approach by having mutual adjustments in the converter and inverter switching pulses. The CSMC strategy is developed in Matlab and experimented using dSPACE‐MicrolabBox. The validation tests are compared with conventional SMC, which shows the betterment of CSMC in robustness and waveshape tracking.

Self-trapping and switching of solitonic pulses in mismatched dual-core highly nonlinear fibers

We investigate experimentally and theoretically effects of the inter-core propagation mismatch on nonlinear switching in dual-core high-index-contrast soft-glass optical fibers. Incident femtosecond pulses of various energy are fed into a single (“straight”) core, to identify transitions between different dynamical regimes, viz., inter-core oscillations, self-trapping in the cross core, and retaining the pulse in the straight core. The transfer between channels, which has solitonic character, is controlled by the pulse’s energy. A model based on the system of coupled nonlinear Schrödinger equations reveals the effect of the mismatch parameter and pulse duration on the diagram of the various energy dependent dynamical regimes. Optimal values of the mismatch and pulse width, which ensure stable performance of the nonlinear switching, are identified. The theoretical predictions are in agreement with experimental findings.

Комбинированный твердотельный замыкающий ключ для коммутации сильноточного импульса

The results of studies of a solid-state closing switch for a high-current pulse switching are presented. The experiments were carried out on a laboratory facility with a capacitive energy storage run down a discharge circuit with electrical-explosive opening switch (EEOS) by a current pulse with an amplitude ~450 kA. The discharge circuit consists of two sections separated by a branch with a solid-state closing switch. A metal foil of the EEOS can be located in an interelectrode gap of the closing switch. The operation of the EEOS leads to a breakdown of the insulation of the closing switch, as a result of which an effective shunting of the section of the discharge circuit containing the EEOS occurs. The developed combined solid-state closing switch in the future is capable of providing multi-channel switching of a high-current pulse to the load synchronously with the EEOS operation.

A novel compact solid-state high power pulse generator based on magnetic switch and square waveform pulse transformer.

The high power pulse generators have been widely used in high power microwave generation and plasma physics research. In this paper, a novel compact solid-state high power pulse generator is studied, numerically and experimentally. The generator is mainly composed of the primary energy supply, the magnetic pulse compressor, the Blumlein type low-impedance pulse forming network, and the square waveform pulse transformer. Especially, design considerations for a solid-state high power pulse generator are proposed. Experimental results show that pulses with a peak power of 2 GW, a duration of 150ns, and a repetitive rate of 10Hz are continuously achieved on a dummy load. The dimension is Φ60 × 210cm2, and the average power density reaches ∼5 W/L. Experimental results show reasonable agreement with numerical analysis.

Maximum Resolution Based Method for Balancing Capacitor Voltages in 7-Level Single Phase Flying-Capacitor Wavelet Modulated Inverters

This paper develops and tests a method for balancing capacitor voltages in 7-level flying-capacitor (FC) inverters, which are operated by the wavelet modulation (WM) technique. This multi-level inverter has two capacitors in each pole, whose voltages deviate due to changes in its loading level. In order to ensure that all switching elements experience identical voltage stresses and no circulating currents, the voltage across each capacitor has to be maintained very close to its reference value. The proposed method to balance the capacitor voltage is based on adjusting the scales of resolution segmented wavelet basis functions, which are used as switching signals to operate a 7-level FC inverter. The adjustments of the scales can vary the widths and locations of switching pulses produced by the WM technique. The proposed capacitor voltage method is structured using a proportional-integral controller to adjust the scales, thus balancing the capacitor voltages. The accuracy, effectiveness, and response speed of the proposed method to balance capacitor voltage are demonstrated through simulation and experimental test cases.