Indirect Vector Control of Linear Induction Motors Using Space Vector Pulse Width Modulation

Vector control schemes have recently been used to drive linear induction motors(LIM)in high-performance applications.This trend promotes the development of precise and efficient control schemes for individual motors.This research aims to present a novel framework for speed and thrust force control of LIM using space vector pulse width modulation(SVPWM)inverters.The framework under consideration is developed in four stages.To begin,MATLAB Simulink was used to develop a detailed mathematical and electromechanical dynamicmodel.The research presents a modified SVPWM inverter control scheme.By tuning the proportional-integral(PI)controller with a transfer function,optimized values for the PI controller are derived.All the subsystems mentioned above are integrated to create a robust simulation of the LIM’s precise speed and thrust force control scheme.The reference speed values were chosen to evaluate the performance of the respective system,and the developed system’s response was verified using various data sets.For the low-speed range,a reference value of 10m/s is used,while a reference value of 100 m/s is used for the high-speed range.The speed output response indicates that themotor reached reference speed in amatter of seconds,as the delay time is between 8 and 10 s.The maximum amplitude of thrust achieved is less than 400N,demonstrating the controller’s capability to control a high-speed LIM with minimal thrust ripple.Due to the controlled speed range,the developed system is highly recommended for low-speed and high-speed and heavy-duty traction applications.

The 266-nm ultraviolet-beam generation of all-fiberized super-large-mode-area narrow-linewidth nanosecond amplifier with tunable pulse width and repetition rate

We report on a compact, stable, all-fiberized narrow-linewidth(0.045 nm) pulsed laser source emitting laser beam with a wavelength of 266 nm, and tunable pulse width and repetition rate. The system is based on all-fiberized nanosecond amplifier architecture, which consists of Yb-doped fiber preamplifiers and a super-large-mode-area Yb-doped fiber power amplifier. The fiber amplifier with a core of 50 μm is used to raise the threshold of the stimulated Brillouin scattering(SBS) effect and to obtain high output power and single pulse energy. Using lithium triborate(LBO) crystal and betabarium borate(BBO) crystal for realizing the second-harmonic generation(SHG) and fourth-harmonic generation(FHG),we achieve 17 μJ(1.73 W) and 0.66 μJ(66 mW), respectively, at wavelengths of 532 nm and 266 nm and a repetition rate of 100 kHz with pulse width of 4 ns. This source has great potential applications in fluorescence research and solar-blind ultraviolet optical communication.

Effect of Peak Power and Pulse Width on Coherent Doppler Wind Lidar’s SNR

The laser device is the core component of coherent Doppler wind lidar.The peak power and pulse width of laser transmitting pulse have important effects on SNR.Based on coherent Doppler wind pulse lidar,the peak power and pulse width influence on SNR is studied on the theoretical derivation and analysis,and the results show that the higher the peak power can realize the greater the signal-to-noise ratio of coherent Doppler wind lidar.But when the peak power is too large,the laser pulse may appear nonlinear phenomenon,which cause the damage of the laser.So,the peak power must be less than the stimulated brillouin scattering power threshold.Increasing the pulse width can make the laser device to output more energy,but it will also make the spatial resolution lower,and the influence of turbulence on SNR will be greater.After a series of simulation analyses,it can be concluded that when the peak power is 650W and the pulse width is 340ns,the SNR of the system can be maximized.In addition,the coherent Doppler wind lidar system is set up to carry out corresponding experimental verification.The experimental results are consistent with the theoretical analysis and simulation,which verifies the correctness of the theoretical analysis and simulation results.It provides theoretical basis and practical ex-perience for the design of laser transmitting pulse in coherent Doppler wind lidar system.

Impacts of laser pulse width and target thickness on laser micro-propulsion performance

In order to optimize the laser ablation performance of a micro-thruster with 1U dimensions,which employs a micro semiconductor laser,the impacts of pulse width and glycidyl azide polymer(GAP)thickness on thrust performance were researched.The results showed that with a GAP thickness of 200μm,the single-pulse impulse(I)increased gradually with the increase in the laser pulse width from 50 to 800μs,while the specific impulse(I_(sp)),impulse coupling coefficient(Cm)and ablation efficiency(η)all reached optimal values with a 200μs pulse width.It is worth noting that the optimal pulse width is identical to the ignition delay time.Both Cmandηpeaked with a pulse width of 200μs,reaching 242.22μN W^(-1)and 35.4%,respectively.With the increase in GAP thickness,I and Cmincreased gradually.GAP of different thicknesses corresponded to different optimal laser pulse widths.Under a certain laser pulse width,the optimal GAP thickness should be the most vertical thickness of the ablation pit,and the various propulsion performance parameters at this time were also optimal.With the current laser parameters,the optimal GAP thickness was approximately 150μm,I_(sp)was approximately 322.22 s,andηwas approximately 34.94%.

Comparison of performance between bipolar and unipolar double-frequency sinusoidal pulse width modulation in a digitally controlled H-bridge inverter system

By deriving the discrete-time models of a digitally controlled H-bridge inverter system modulated by bipolar sinusoidal pulse width modulation(BSPWM) and unipolar double-frequency sinusoidal pulse width modulation(UDFSPWM) respectively,the performances of the two modulation strategies are analyzed in detail.The circuit parameters,used in this paper,are fixed.When the systems,modulated by BSPWM and UDFSPWM,have the same switching frequency,the stability boundaries of the two systems are the same.However,when the equivalent switching frequencies of the two systems are the same,the BSPWM modulated system is more stable than the UDFSPWM modulated system.In addition,a convenient method of establishing the discrete-time model of piecewise smooth system is presented.Finally,the analytical results are confirmed by circuit simulations and experimental measurements.

All-fiberized very-large-mode-area Yb-doped fiber based high-peak-power narrow-linewidth nanosecond amplifier with tunable pulse width and repetition rate

We demonstrate an all-fiberized narrow-linewidth nanosecond amplifier with high peak power,tunable pulse width,and repetition rate.A fiber-coupled narrow-linewidth laser diode operating at 1064.1 nm is employed as the seed source,which is gain-switched to generate nanosecond pulses with tunable pulse widths of 1-200 ns and tunable repetition rates of10 Hz-100 kHz.By utilizing a very-large-mode-area Yb-doped fiber with a core diameter of 50 μm in the power amplifier,thresholds of the stimulated Brillouin scattering at different pulse widths and repetition rates are increased.The maximum average power reaches 30.8 W at the pulse width of 4 ns and a repetition rate of 100 kHz,corresponding to an optical-tooptical conversion efficiency of ~55.2%.Pulse energy and peak power are calculated to be 0.2 mJ and 50 kW,respectively,which are limited by stimulated Brillouin scattering.The 3-dB spectral linewidth remains around 0.05 nm during the power scaling process.The stimulated Brillouin scattering limited output powers at different pulse widths and repetition rates are investigated.Peak power of 47.5 kW(0.19 mJ) is obtained for the 4 ns pulses at a repetition rate of 50 kHz,which is nearly the same as that of 4 ns pulses at 100 kHz.When the pulse width of the seed source is increased to 8 ns,peak powers/pulse energies are decreased to 19.6 kW/0.11 mJ and 13.3 kW/0.08 mJ at repetition rates of 50 kHz and 100 kHz,respectively.

Improved Protein Transfer Efficiency and Signal Intensity in BlotMan Using Pulse Width Modulation

BlotMan is a protein blotting device that allows generating multiple membranes from a single polyacrylamide gel. To transfer all proteins uniformly with the same efficiency regardless of protein size, BlotMan employs pulse-width-modulated (PWM) voltage that applies a higher average voltage to a larger protein species. BlotMan can be controlled not only by its custom-made interface but also by a smart phone via Bluetooth technology. In this study, we examined effects of PWM signals (50%, 60%, and 80% duty cycle) on transfer efficiency and signal intensity in comparison to a constant voltage signal (100% duty cycle). The result revealed that in response to the same average voltage of 150 V, a lower duty cycle with a higher maximum voltage increased transfer efficiency as well as sharpness of transferred proteins. We validated BlotMan’s capability using a chondrosarcoma cell line (SW1353 cells) and a breast cancer cell line (MDA-MB231 cells) in response to antitumor chemical agents. BlotMan successfully generated 5 membranes from a single gel and detected 5 protein species such as c-Src, eukaryotic translation initiation factor 2 alpha (eIF2), phosphorylated eIF2, lamin B, and actin. Collectively, we demonstrated herein that BlotMan reduces an amount of protein samples by generating multiple membranes from a single gel and improving signal intensity with PWM voltage signals.

Capacitor Pattern H-Bridge Multilevel Inverter (CPHMLI) Using Phase Diposition Pulse Width Modulation for Grid Applications

This work presents an implementation of an innovative single phase multilevel inverter using capacitors with reduced switches. The proposed Capacitor pattern H-bridge Multilevel Inverter (CPHMLI) topology consists of a proper number of Capacitor connected with switches and power sources. The advanced switching control supplied by Pulse Width Modulation (PDPWM) to attain mixed staircase switching state. The charging and discharging mode are achieved by calculating the voltage error at the load. Furthermore, to accomplish the higher voltage levels at the output with less number of semiconductors switches and simple commutation designed using CPHMLI topology. To prove the performance and effectiveness of the proposed approach, a set of experiments performed under various load conditions using MATLAB tool.

Global synchronous discontinuous pulse width modulation method with fast calculation capability for distributed three-phase inverters

When multiple distributed converters are integrated, the high frequency harmonics will randomly accumulate at the point of common coupling(PCC). This paper proposes a new fast global synchronous discontinuous pulse width modulation(GSDPWM) method of threephase inverters to effectively attenuate the high frequency current harmonics at PCC. Firstly, the basic principle and the realization method of GSDPWM for three-phase inverters are explained, which can be employed for different modulation types. Then a fast calculation method,which can equally derive the minimized total harmonic distortion(THD) of total current, is proposed to release the calculation burden. Finally, MATLAB simulations and experimental results are presented to verify the performance of GSDPWM.

Wide Pulse Width Electroacupuncture Ameliorates Denervation-Induced Skeletal Muscle Atrophy in Rats via IGF-1/PI3K/Akt Pathway

Objective:To evaluate the effect of the pulse width of electroacupuncture(EA)in the treatment of denervation-induced skeletal muscle atrophy in rats and examine the role of insulin-like growth factor 1(IGF-1)/phosphatidylinositol 3-kinase(PI3 K)/Akt signaling pathway during EA.Methods:Sciatic nerve functional index(SFI),muscle wet weight and the cross-sectional area(CSA)of the gastrocnemius muscle were analyzed after treatment in model rats with EA of various pulse widths(0.5,50,100 and 200 ms).The apoptosis index(AI)and paired box(PAX)3 and PAX7 protein expression were also determined.Further,the mRNA and protein expressions of components of IGF-1/PI3 K/Akt pathway and their downstream targets were determined,along with the inhibiting effect of the pathway with a PI3-specific inhibitor.Results:EA with a pulse width of 200 ms was found to have the best effect with regard to increasing SFI,CSA and muscle weight,decreasing AI,and increasing the expression of PAX3 and PAX7.The IGF-1/PI3 K/Akt pathway was found to be activated by denervation,although the downstream forkhead box O(FoxO)pathway was not suppressed by its activation.The PI3 K/Akt pathway and its downstream molecule mammalian target of rapamycin(mTOR)were up-regulated further by EA to promote muscle protein synthesis.Meanwhile,the expressions of downstream FoxO and F-box protein 32(ATROGIN-1)were down-regulated to reduce protein degradation.Conclusions:EA with 200-ms pulse width was found to have a more significant effect than 0.5-ms EA.The positive effects of EA disappeared after inhibition of the PI3 K/Akt pathway.

Pulsed LD side-pumped MgO：LN electro-optic cavity-dumped 1123 nm Nd： YAG laser with short pulse width and high peak power

We report a cavity-dumped 1123 nm laser with narrow pulse width and high peak power by an Mg O: LN crystal electrooptic(EO) modulator. Based on the structural optimization design of a folded biconcave cavity using the 808 nm pulsed laser diode(LD) side-pumped ceramic Nd: YAG rod, output pulses with maximum pulse energy and peak power up to39.6 m J and 9.73 MW were obtained, corresponding to 100 Hz repetition rate and 4.07 ns pulse width. The instabilities of pulse width and pulse energy were ±1.55% and ±2.06%, respectively. At the highest repetition rate of 1 kHz, the pulse energy, pulse width, and peak power were 11.3 mJ, 5.05 ns, and 2.24 MW, respectively. The instabilities of pulse width and pulse energy were ±2.65% and ±3.47%, respectively.

Dual-frequency Discontinuous Space Vector Pulse Width Modulation for Five-phase Voltage Source Inverters with Harmonic Injection

This paper proposes a dual-frequency discontinuous space vector pulse width modulation(DFDSVPWM)for a five-phase voltage source inverter with harmonic injection.In this modulation,for dual-frequency voltage output and reduction of switching losses,two different zero-vector-inserted modes are flexibly employed by alternatively using two types of zero vectors.Based on the comparison with continuous SVPWM,the idea and principle of the proposed DFDSVPWM are analyzed and an example of PWM signals for one bridge is also presented.For switching losses analysis,the impact factors and the calculation method are investigated and the corresponding implementation is given as well.The simulation and experimental results from a prototype verify the correctness and effectiveness of the proposed modulation and it has the advantages of outputting dual-frequency voltage and reducing switching losses.

Analysis of Transient Pulse Electroosmotic Flow of Maxwell Fluid through a Circular Micro-Channel Using Laplace Transform Method

A semi-analytical solution is presented using method of Laplace transform for the transient pulse electroosmotic flow (EOF) of Maxwell fluid in a circular micro-channel. The driving mode of pulse EOF here is considered as an ideal rectangle pulse. The solution involves solving the linearized Poisson-Boltzmann (P-B) equation, together with the Cauchy momentum equation and the general Maxwell constitutive equation. The results show that the profiles of pulse EOF velocity vary rapidly and gradually stabilize as the increase of time within a half period. The velocity profiles at the center of the micro-channel increase significantly with relaxation time , especially for the smaller pulse width a. However, as the pulse width a increases, this change will be less obvious. At the same time, the different change frequency of velocity profiles will slow down, which means a long cycle time. Additionally, the time needed to attain the steady status becomes longer with the increase of relaxation time and pulse width a.

Talk about Several Time Periodic Pulse Electroosmotic Flow of Maxwell Fluid in a Circular Microchannel

Using the method of Laplace transform, analytical expressions are derived for the time periodic pulse electroosmotic flow (EOF) velocity of the triangle and sawtooth of Maxwell fluid in circular microchannel. The solution involves analytically solving the linearized Poisson-Boltzmann (P-B) equation, together with the Cauchy momentum equation and the general Maxwell constitutive equation. By numerical computations of inverse Laplace transform, the effects of electrokinetic width K, relaxation time and pulse width a on the above several pulse EOF velocities are investigated. In addition, we focused on the comparison and analysis of the formulas and graphs between the triangle and sawtooth pulse EOF with the rectangle pulse EOF. The study found that there are obvious differences in formulas and graphs between triangle and sawtooth pulse EOF with rectangle pulse EOF, and the difference mainly depends on the different definitions of the three kinds of time periodic pulse waves. Finally, we also studied the stability of the above three kinds of pulse EOF and the influence of relaxation time on pulse EOF velocity under different pulse widths is discussed. We find that the rectangle pulse EOF is more stable than the triangle and sawtooth pulse EOF. For any pulse, as the pulse width a increases, the influence of the relaxation time on the pulse EOF velocity will be weakened.

An Improved Submodule Unified Pulse Modulation Scheme for a Hybrid Modular Multilevel Converter

This paper presents an improved submodule unified pulse width modulation(SUPWM)scheme for a hybrid modular multilevel converter(MMC)composed of half-bridge submodules(HBSMs)and full-bridge submodules(FBSMs).The proposed SUPWM scheme can achieve an output voltage of(2N+1)(where N is the number of submodules in each arm)levels,which is the same as that of the carrier-phase-shifted PWM(CPSPWM)scheme.Meanwhile,the proposed SUPWM scheme can alleviate the uneven loss distributions between the left leg and right leg in FBSMs of the hybrid MMC.Moreover,the capacitor voltages of the sub-modules can be well balanced without complicated closed-loop voltage balancing controllers.The validity of the proposed SUPWM scheme is verified by both the simulated and experimental results.

Optimized Design and Analysis of Single-Phase and Three-Phase Inverters for Efficient Power Conversion: A Comparative Study

A large amount of switching loss occurs in the inverter. From this point of view, an inverter design should be optimized for which size and cost will be minimum along with increasing efficiency. The main aim of this paper is the analysis and development of single-phase and three-phase inverter to design with MOSFET and IGBT as power elements by sinusoidal pulse width modulation (SPWM) technique using MATLAB Simulink software and compare their difference with the practical inverter. This work proposes different multilevel stages for the cascaded H-Bridge inverter to enhance the output voltages. Then compare their performance, harmonic distortion, and frequency spectrum. The hardware of an inverter circuit has been developed using the SG3524 microcontroller. The main goal of this design is to generate a sine wave with fewer harmonics, while keeping the cost and complexity of the circuit low. The designed inverter has undergone testing with different AC loads and is primarily intended for low-power applications, as lamps, fans, and chargers. This design aims to provide a reliable and efficient inverter solution for these specific applications.

Genetic Algorithm Based 7-Level Step-Up Inverter with Reduced Harmonics and Switching Devices

This paper presents a unique voltage-raising topology for a single-phase seven-level inverter with triple output voltage gain using single input source and two switched capacitors.The output voltage has been boosted up to three times the value of input voltage by configuring the switched capacitors in series and parallel combinations which eliminates the use of additional step-up converters and transformers.The selective harmonic elimination(SHE)approach is used to remove the lower-order harmonics.The optimal switching angles for SHE is determined using the genetic algorithm.These switching angles are com-bined with a level-shifted pulse width modulation(PWM)technique for pulse generation,resulting in reduced total harmonic distortion(THD).A detailed com-parison has been made against other relevant seven-level inverter topologies in terms of the number of switches,drivers,diodes,capacitors,and boosting facil-ities to emphasize the benefits of the proposed model.The proposed topology is simulated using MATLAB/SIMULINK and an experimental prototype has been developed to validate the results.The Digital Signal Processing(DSP)TMS320F2812 board is used to generate the switching pulses for the proposed technique and the experimental results concur with the simulated model outputs.

A Sensor-less Surface Mounted PMSM for Electronic Speed Control in Multilevel Inverter

Recent advancements in power electronics technology evolves inverter fed electric motors.Speed signals and rotor position are essential for controlling an electric motor accurately.In this paper,the sensorless speed control of surface-mounted permanent magnet synchronous motor(SPMSM)has been attempted.SPMSM wants a digital inverter for its precise working.Hence,this study incor-poratesfifteen level inverter to the SPMSM.A sliding mode observer(SMO)based sensorless speed control scheme is projected to determine rotor spot and speed of the multilevel inverter(MLI)fed SPMSM.MLI has been operated using a multi carrier pulse width modulation(MCPWM)strategy for generation offif-teen level voltages.The simulation works are executed with MATLAB/SIMU-LINK software.The steadiness and the heftiness of the projected model have been investigated under no loaded and loaded situations of SPMSM.Furthermore,the projected method can be adapted for electric vehicles.

Design and Implementation of Smart Power Voltage and Frequency Synchroniser in Power Distribution System

Voltage and frequency are usually considered and assessed independently in the design and operation of electrical networks. However, these two are linked. Each and every malfunctioning electrical system has an impact on both voltage and frequency. This paper presents the opportunity for monitoring the distributed electrical energy by means of a system that monitors, controls, and provides a breakpoint based on high or low voltage and frequency tripping mechanism that avoids any damage to the load. The designed system comprised a switch mode power supply (SMPS), a direct digital synthesizer (DDS), and PIC16F876A microcontroller techniques for stable voltage and frequency outputs. Proteus design suite version 8.11 software and Benchcope SDS1102CN were used for modeling and simulation. The hardware prototype was implemented at a telecom cell site for data capturing and analysis. Test results showed that the implementation of the prototype provided stable and constant outputs of 222 V/50 Hz and 112 V/60 Hz which constituted 99% and 99.8% efficiency for voltage and frequency performance respectively. The paper also discusses different technologies that can be adopted by the system to mitigate voltage and frequency effects on customer appliances.