Sinusoidal Output Research Articles

Improvement of output current waveforms using SVM technique and fuzzy logic controller for matrix converter

Purpose – The use of power electronic equipment such as conventional AC-DC-AC converters cause several problems in electrical networks and its components. They generate harmonic currents and disturb the electrical power sources; so, it is necessary to research alternative topologies of power electronic converters based on advanced intelligent controllers, which reduce or even eliminate harmonics to achieve energy-saving and environmental protection. The use of matrix converter (MC) is, considered as an attractive solution to maintain pure sinusoidal input and output current waveforms. The paper aims to discuss this issue. Design/methodology/approach – The studied system is composed of a three phase matrix converter (TMC) feeding a linear R, L load and a trees phase rectifier considered as a non-linear load; the proposed control strategy is based on a fuzzy logic controller (FLC) associated to the (space vector modulation) SVM modulation technique, this choice is motivated by the advantages that represent the combination of FLC and SVM in term of power quality enhancement in both input and output sides of MC. Findings – The model is validated based on simulation results that illustrate the effectiveness of the proposed system in term of power quality amelioration. The high performance of the proposed FLC is illustrated in all study cases especially in the case of perturbed input voltage, it is not only able to keep the whole system stable, but also it reduces harmonic distortion THD to respect international standards recommendation. Originality/value – In this paper, an associated linear (RL), non-linear loads and TMC is studied. From the mathematical point of view, the MC is modeled and analyzed. From the technique point of view, the MC allows sinusoidal current absorbance from the network with good qualities in term of harmonic distortion compensation, and high reliability under various loads and disturbed input voltage.

A High Speed MOSFET for Switching Application

This work introduces a new super junction MOSFET. High switching speed is an essential parameter in this device. Negative resistance in gas electron between GaAs and AlGaAs is used to design this structure. The new designed device stores much less charges in its channel, because its junction and parasitic capacitance are small. As well, in on-state it has lower resistance relative to the traditional device. Therefore, the amount of RDS × QC which is Figure of Merit (FOM) will decrease, enormously. The designed MOSFET has been applied in a 3–phase inverter and its performance for giving a sinusoidal output has been showed. All the simulations have been done in SILVACO software.

A Low-Speed, High-Torque Motor Drive Using a Modular Multilevel Cascade Converter Based on Triple-Star Bridge Cells (MMCC-TSBC)

This paper provides experimental verification of a modular multilevel cascade converter based on triple-star bridge cells (MMCC-TSBC) for a low-speed, high-torque motor drive. The TSBC is one of direct ac-to-ac power converters capable of achieving bidirectional power flow and drawing/feeding three-phase sinusoidal input (supply-side) and output (motor-side) currents with any power factor at both sides. This paper designs, constructs, and tests a downscaled drive system combining a 400-V, 15-kW, phase-shifted-carrier PWM TSBC equipped with four bridge cells per cluster and a 320-V, 38-Hz, 6-pole, 15-kW induction motor loaded at the rated torque. Experimental waveforms obtained from the downscaled drive system verify stable operation across a broad range from a standstill to the rated speed, showing satisfactory start-up performance.

A Four-Switch Three-Phase SEPIC-Based Inverter

The four-switch three-phase (FSTP) inverter has been proposed as an innovative inverter design to reduce the cost, complexity, size, and switching losses of the dc–ac conversion system. Traditional FSTP inverter usually operates at half the dc input voltage; hence, the output line voltage cannot exceed this value. This paper proposes a novel design for the FSTP inverter based on the topology of the single-ended primary-inductance converter (SEPIC). The proposed topology provides pure sinusoidal output voltages with no need for output filter. Compared to traditional FSTP inverter, the proposed FSTP SEPIC inverter improves the voltage utilization factor of the input dc supply, where the proposed topology provides higher output line voltage which can be extended up to the full value of the dc input voltage. The integral sliding-mode control is used with the proposed topology to optimize its dynamics and to ensure robustness of the system during different operating conditions. Derivation of the equations describing the parameters design, components ratings, and the operation of the proposed SEPIC inverter is presented in this paper. Simulation model and experimental setup are used to validate the proposed concept. Simulations and experimental results show the effectiveness of the proposed inverter.

Analytical circuit oriented modelling and performance assessment of modular multilevel converter

This study presents a detailed time domain model of a modular multilevel converter (MMC) to provide an alternative form of evaluation of the converter dynamic performance, for example, during AC or DC fault conditions. The purpose of the model is to accurately reflect the converter behaviour to be used in control systems design. It can also be beneficial to predict the steady state or transient state of the converter with fixed or variable inputs. In an MMC, the capacitor voltages are modulated using pulse-width modulation (PWM) to fabricate a sinusoidal output voltage. With time, and because of the PWM action, the capacitors get charged or discharged. Therefore the circuit behaves as a time-variant circuit. The analysis is based on the equivalent circuit derived from the converter differential expressions at any time instant in a piecewise fashion. The usefulness and accuracy of the theoretical study is validated for the three-phase MMC topology by simulation results with respect to normal operation, start-up process, cell short-circuit fault, line-to-ground and DC-side fault conditions. Experimental tests are carried out through a scaled-down laboratory prototype.

Performance of an optical encoder based on a nondiffractive beam implemented with a specific photodetection integrated circuit and a diffractive optical element.

In this paper, we study the incremental signal produced by an optical encoder based on a nondiffractive beam (NDB). The NDB is generated by means of a diffractive optical element (DOE). The detection system is composed by an application specific integrated circuit (ASIC) sensor. The sensor consists of an array of eight concentric annular photodiodes, each one provided with a programmable gain amplifier. In this way, the system is able to synthesize a nonuniform detectivity. The contrast, amplitude, and harmonic content of the sinusoidal output signal are analyzed. The influence of the cross talk among the annular photodiodes is placed in evidence through the dependence of the signal contrast on the wavelength.

Analysis of frequency and amplitude in CMOS differential ring oscillators

In this paper, a new method for computing the amplitude and frequency of differential ring oscillators (ROs) is proposed. The analysis is performed in two separate parts. In the first of these, equations are derived with the assumption of a sinusoidal waveform of outputs, while in the other, the outputs are assumed to be exponential. It is shown that the derived equations for frequency and amplitude are sufficiently exact. In addition, conditions in which sinusoidal and exponential output occur are thoroughly discussed. In the instances in which the results did not satisfy the necessary conditions for sinusoidal output, the output is assumed to be exponential. Moreover, the related analytical equations are written, and the new expressions for frequency and amplitude of ROs are derived. Analytical results are confirmed by simulation results, using the Taiwan Semiconductor Manufacturing Company 0.18µm technology model. The simulation results indicate the high level of accuracy of the proposed model.

The Three-Level Sine-Wave Inverter with Power Factor Correction (PFC)

Nowadays, the uninterruptible power supply (UPS) is important in reliability for electric device. The UPS need high quality electricity. Therefore, the simulation of the three-level sine-wave inverter with power factor correction (PFC) is proposed in this paper. Moreover, the circuit’s guidelines of the active PFC controller in the active PFC and the sinusoidal output voltage are also presented. Validity of the proposed the three-level sine-wave inverter with the active PFC is confirmed by simulation. The simulation results show the very small current harmonics, the input power factor most nearly unity and constant output voltage when the suddenly step-load changed.

Development of Simultaneous Measurement Method of Potentiodynamic Polarization Curve and Impedance Spectra Determined By Wavelet Transformation

Electrochemical impedance spectroscopy (EIS) is powerful method to analyze dissolution mechanisms of metals because time constants for elementary reaction steps and formation of reaction intermediate can be discriminated. Impedance spectrum is generally measured by using a frequency response analyzer (FRA) whose principle is on the basis of Fourier transformations of sinusoidal input and output signals. Ragoisha et al. (1) proposed a potentiodynamic electrochemical impedance spectroscopy (PDEIS), in which sinusoidal wavelet is superimposed on terrace of the each potential step during stepwise potential scan. Our group (2, 3) developed a simultaneous measurement method of a potential scanning impedance spectroscopy (PSIS) and impedance spectra determined by wavelet transformation (WT). In this method, it is possible to obtain the successive impedance spectra with measuring the potentiodynamic polarization curve of metal electrode simultaneously and to determine the instantaneous impedance. We used complex Morlet mother wavelet in order to obtain the complex number data in the frequency domain. This mother wavelet is obtained by combining the Gaussian function and sinusoidal term. The time-dependent impedance of the dissolving iron electrode can be determined by calculating cross spectra of the wavelet coefficients of current and potential signals. In the present paper, the potential step signal was used for the input signal. In the results, the impedance spectrum described the capacitive loop in the high frequency range and the inductive loop in the low frequency range, which was determined by WT. It was found that the impedance spectrum in the low frequency range determined by WT is related to the holding time of input potential signal. The inductive loop observed in the low frequency range and the holding time of input potential signal were discussed. Reference: 1. G. A. Ragoisha and A. S. Bondarenko, Electrochimica Acta, 50, 1553 (2005). 2. M. Itagaki, K. Isobe, Y. Hoshi, I. Shitanda, 226th ECS meeting abstract, #753 (2014). 3. M. Itagaki, A. Taya, K. Watanabe, Electrochemistry, 70, 779 (2002).

Space vector pulse‐width modulation technique for an eleven‐phase voltage source inverter with sinusoidal output voltage generation

This paper discusses the space vector pulse width modulation (SVPWM) scheme for an eleven-phase two-level voltage source inverter (VSI), aimed at producing a sinusoidal output voltage waveform. Generalised space vector theory is used to realise the SVPWM. As per the general inverter switching theory, there are 211 = 2048 switching states that yield 2046 active voltage space vectors and one zero voltage vector, which results with two switching states. Out of the total of 2046 active voltage vectors, the most suitable set comprising 110 active voltage vectors is identified and is utilised in the implementation of the SVPWM. The sinusoidal voltage is obtained by controlling the duty cycles of the applied voltage space vectors in such a way that the non-zero reference voltage in the first (d-q) plane is achieved, while simultaneously zeroing the average voltage in the other four (x-y) planes in accordance with the zero references. The theoretical results are verified by experimentation using a passive resistive-inductive load. Finally, experimentally obtained THD values of the phase voltage and current for the eleven-phase SVPWM are compared with the corresponding values obtained using SVPWM for other odd phase numbers. Keywords: Eleven-phase system, Multi-phase drives, Space vector PWM, Voltage source inverter

A Novel Quadrant Search Based Mitigation Technique for DC Voltage Fluctuations in Multilevel Inverters

The hybrid cascaded multilevel inverter (HCMLI) is a popular converter topology that is being increasingly used in high power medium voltage drives. The intricacy of the control technique for a HCMLI increases with the number of levels and due to fluctuating dc voltages. This paper presents a novel offline quadrant search based space vector modulation technique to synthesize a sinusoidal output from a dispersed pattern of voltage vectors due to different voltages in the auxiliary unit. Such an investigation has never been reported in the literature and it is being attempted for the first time. The method suggested distributes the voltage vectors for a reduced total harmonic distortion at minimal computation. In addition, the proposed algorithm determines the maximum modulation index in the linear modulation range in order to synthesize a sinusoidal output for both normal and abnormal vector patterns. It is better suited for a wide range of practical applications. It is particularly well suited for renewable source fed inverters which utilize large capacitor banks to maintain the dc link, which are prone to such slow fluctuations. The proposed quadrant search space vector modulation technique is simulated using MATLAB/SIMULINK and implemented using a Nexys-2 Spartan-3E FPGA for a developed prototype.

Indirect Matrix Converter for Hybrid Electric Vehicle Application with Three-Phase and Single-Phase Outputs

This paper presents an indirect matrix converter (IMC) topology for hybrid electric vehicle (HEV) application with three-phase and single-phase outputs. The HEV includes mechanical, electrical, control, and electrochemical systems among others. In the mechanical system, a traction motor and a compressor motor are used to drive the HEV. The traction motor and the compressor motor are usually operated as three-phase and single-phase motors, respectively. In this respect, a dual AC-drive system can operate the traction and the compressor motor simultaneously. Furthermore, compared to a conventional dual matrix converter system, the proposed topology can reduce the number of switches that the dual outputs share with a DC-link. The application of this system for HEV has advantages, like long lifetime and reduced volume due to the lack of a DC-link. The proposed control strategy and modulation schemes ensure the sinusoidal input and output waveforms and bidirectional power transmission. The proposed system for the HEV application is verified by simulation and experiments.

New MCPWM Strategy for a CHBMLI with Induction Motor Load

The paper attempts to develop a new pulse width modulation (PWM) strategy suitable for the cascaded H-Bridge multilevel inverter (CHBMLI) with a view to improve the performance of the Induction motor connected to it. The philosophy endeavors to arbitrate on the appropriate use of the reference sine wave in the generation of switching pulses for the power switches in the MLI. It dwells on the choice of the portions that essay an effective change of the modulation index to bring about a variation in the output voltage. The inherent poignant features of the phase disposition (PD) modulation technique intertwine with the reformulated philosophy to trace a nearly sinusoidal output voltage. The etiquette framework orchestrates to dispense with the higher frequency components and furnish an improved output voltage spectrum. The relatively lower total harmonic distortion (THD) indices for both output phase and line voltages allow the 60 degree PWM to claim an enhanced performance for the CHBMLI and in turn the induction motor. The delicacies of the field programmable gate array (FPGA) augur to realize the pulses and the experimental results from a suitable prototype adequately validate the simulated performance. The emphasis entices for opening up the portals of the traditional topology to a new dimension and ensures its use in practical applications.

Design of a rotary valve orifice for a continuous wave mud pulse generator

High-speed downhole transmission technology plays an important role in measurement while drilling (MWD) and logging while drilling (LWD) systems, where the continuous wave mud pulse transmission method is currently the most advantageous method for wireless downhole transmission. To increase the production rate, transmission distance and testing intensity and to decrease the ground detected difficulty of continuous wave mud signals, the valve orifice must be optimized to satisfy the requirements for the continuous sinusoidal pressure output. In this study, an improved arc-fillet-line triangular valve orifice is designed based on a general line triangular valve orifice according to the relationships between the fluid differential pressure of a thin-walled cutting edge and the fluid flow area and between the correlation coefficient of the theoretical pressure difference and standard sinusoidal signal. The improved orifice is designed by calculating the variation between the flow area and relative rotation angle of the rotor to the stator through the established polar coordinate equations. The optimized valve structure is simple and easy to machine, and highly similar sinusoidal pressure wave signals can be achieved during practical operation to meet the requirements of the instrument design.

Investigation of Line Current Harmonics in Cascaded Multi-level Inverter Based Induction Motor Drive and an Adaptive On-line Selective Current Harmonic Elimination Algorithm

Multilevel Inverters (MLIs) have drawn increasing attention in numerous applications, especially in drives, distributed energy resources area, utility etc. MLIs have the ability to synthesize a near sinusoidal output voltage wave with minimal Total Harmonic Distortion (THD) in low frequency switching. Even though they offer lower THD, the presence of lower order harmonics is objectionable and harmonics elimination in Multilevel Inverters (MLIs) has been receiving immense attention for the past few decades. Existing Selective Harmonic Elimination (SHE) techniques can eliminate the objectionable lower order voltage harmonics with low switching frequency by solving the Fourier non-linear transcendental equations of the output voltage. The line current harmonics has a direct role to play on the magneto-motive force and results in increase of mismatching of air-gap permeance, vibrations, acoustic noise etc. This study proposes Normalized Least Mean Squares (NLMS) algorithm based scheme to eliminate the selected dominant harmonics in load current using only the knowledge of the frequencies to be eliminated. The algorithm is simulated using MATLAB/SIMULINK tool for a three-phase VSI to eliminate the fifth and seventh harmonics. The informative simulation results verify the validity and effectiveness of the proposed algorithm. The system performance is analyzed based on the simulation results considering Total Harmonic Distortion (THD), magnitude of eliminated harmonics and frequency spectrum.

High-Quality Sine Wave Generation Using a Differential Boost Inverter at Higher Operating Frequency

Buck-converter-based topologies are used to generate high-frequency sinusoidal outputs. Buck-based inversion circuits such as voltage source inverters or class-D amplifiers have inherent control-to-output linearity in large-signal sense. However, in these topologies, the instantaneous output is always smaller than the dc-input during linear modulation. A differential boost inverter (DBI) is a boost-based topology that is used to generate a sinusoidal output. In DBI, the instantaneous output can be higher or lower than the dc-input voltage. DBI exhibits nonlinear control-to-output behavior in large-signal dynamic sense. Therefore, generating a high-frequency sinusoidal output using this topology is a challenge. The issues associated with a DBI for high-frequency sine wave generation are characterized in this paper. Conventional linear and nonlinear control techniques fail to produce a high-quality sine wave output at higher operating frequency. A nonlinear feedback linearization technique is proposed, which forces the output to be linear with respect to the reference even at higher operating frequency. This leads to a high-frequency high-quality sine wave generation using a DBI. The proposed modulator is verified using a laboratory prototype to generate a sine wave up to 2 kHz. A triangular wave of 100-Hz frequency is also generated by the proposed technique. Superior dynamic responses of a dynamic linearizing modulator controlled DBI for a step change in frequency, load current, input voltage, and reference are also experimentally verified.

Direct torque control space vector modulation of five-phase interior permanent magnet synchronous motor using matrix converter

Matrix converters (MCs) have many advantages over conventional inverters such as sinusoidal input and output waveforms, operation with close to unity input power factor and more compact sizes. Direct torque control (DTC) is known as one of the popular methods in controlling AC motor drives. This paper presents indirect space vector modulation (ISVM) approach as a new modulation method for a three-to-five-phase MC and calculates the maximum modulation index of this converter based on a mathematical solution. Then, new DTC-SVM is proposed for a five-phase interior permanent magnet synchronous motor, fed by a three-to-five-phase MC. The simulation results show that the proposed drive system has very low flux and torque ripples, sinusoidal input and output currents, constant switching frequency, operation with close to unity input power factor and regenerative braking capability.

TSBC方式モジュラー・マルチレベル・カスケード変換器（MMCC-TSBC）を用いた低速高トルクモータ駆動

SUMMARY This paper provides an experiment-based discussion on a modular multilevel cascade converter based on triple-star bridge cells (MMCC-TSBC) for a low-speed high-torque motor drive. The TSBC is a direct ac-to-ac power converter capable of achieving bidirectional power flow as well as drawing and feeding three-phase sinusoidal input (supply-side) and output (motor-side) currents with any power factor at both sides. This paper discusses active dc-capacitor-voltage control applied to the low-speed, high-torque motor drive. A specially designed downscaled system combining a 320-V, 38-Hz, 6-pole, 15-kW induction motor with a 400-V, 15-kW TSBC is constructed and tested to confirm the validity of the motor drive. Experimental waveforms obtained from the downscaled system confirm stable operation with the rated load torque across a range from a standstill to the rated speed, including satisfactory start-up performance.

Investigation of multimodule buck–boost inverter‐based HVDC transmission system

In high voltage direct current (HVDC) systems, the semiconductor devices have to be connected in series to obtain the required high-voltage ratings. This study proposes a new HVDC configuration, namely, multimodule buck–boost inverter for HVDC transmission applications which avoids series connection of large number of semiconductor switches. In addition, it provides a blocking capability against DC side faults. The proposed configuration consists of several simple buck–boost converters which are assembled together to meet the requirements of high-voltage high-power applications. This paper studies the dynamic performance of the proposed system under different operating conditions, and the results were satisfactory. The main advantages of the proposed configuration are: (i) pure sinusoidal output which minimises/eliminates the requirements for supplementary AC filters and offers an inherent suppression to the common mode voltages, (ii) very low dv/dt stresses and (iii) complete blocking capability of AC side contributions during DC side faults. This study discusses the system architecture, passive components selections, voltage and current ratings of its semiconductor devices and the required controllers. A comparison between the proposed configuration and other existing HVDC technologies is also presented in this study.

Interior PM Generator for Portable AC Generator Sets

For portable ac electric generator sets, it is desired to maintain a constant output voltage under load. With wound-field synchronous generators, this is done using field current (excitation) control. This type of control is not possible with permanent magnet (PM) machines; however, theoretical analysis is used to show that acceptable output voltage regulation can be obtained by two alternative design approaches for interior PM machines. The design of an example 4-pole 16-kW machine is described, and experimental results are provided, demonstrating its sinusoidal output waveform, high voltage regulation, and high efficiency.