Sinusoidal Output Research Articles

Low-Power Multichannel Wireless Transmitter

In this paper, a nonisolated dc−ac inverter topology, which enables a true single-stage direct conversion from a single dc input supply to multiple ac output power sources by using only one inductor in the power stage, is proposed. Compared with the conventional multiple-output parallel half-bridge or full-bridge inverters, the proposed single-stage single-inductor multiple-output (SIMO) inverter topology achieves a smaller number of inductors and power switches, high power density, scalability to multiple ac outputs, and independent power controllability for each ac output. A useful application of the proposed SIMO inverter is to drive an array of transmitting coils simultaneously for wireless power transfer applications. An experimental prototype has been developed to demonstrate the effectiveness of a single-inductor three-output boost-derived inverter without cross regulation. Experimental results show that precise and independent peak voltage regulation of each individual sinusoidal ac output is attainable with the proposed SIMO inverter.

A Three-Phase Grid-Connected Inverter Equipped With a Shunt Instantaneous Reactive Power Compensator

This paper introduces a three-phase grid-connected inverter for commercial-scale photovoltaic systems. The circuit topology combines an ac-inductor-less active bridge with a parallel-connected pulsewidth modulation inverter acting as an instantaneous reactive power compensator. The active bridge, called a 120° conduction inverter, operates at a switching frequency equal to the grid frequency and outputs a 120° rectangular current, while the compensator eliminates the harmonic currents included in the rectangular current. The main advantage of this strategy is the reduction in size of the required ac inductor by a factor of 4, as well as the reduction of power losses in the switching devices. The theoretical analysis clearly shows that the compensator can synthesize a sinusoidal output current by controlling only instantaneous reactive power, thus eliminating the need for electrolytic capacitors. A 5-kW experimental setup validates the operating principle and the control method of the proposed inverter and exhibits an inverter efficiency as high as 99.2% with Si superjunction mosfet s.

Simplified Space Vector Pulse Width Modulation Based on Switching Schemes with Reduced Switching Frequency and Harmonics for Five Level Cascaded H-Bridge Inverter

This paper presents a simplified control strategy of SVPWM with a three segment switching sequence and 7 segment switch frequency for high power multilevel inverter. In the proposed method, the inverter switching sequences are optimized for minimization of device switching sequence frequency and improvement of harmonic spectrum by using the three most derived switching states and one suitable redundant state for each space vector. The proposed 3-segment sequence is compared with conventional 7-segment sequence similar for five level Cascaded H-Bridge inverter with various values of switching frequencies including very low frequency. The output spectrum of the proposed sequence design shows the reduction of device switching frequency and states current and line voltage. THD this minimizing the filter size requirement of the inverter, employed in industrial applications. Where sinusoidal output voltage is required<em>.</em>

Finite-Control-Set Predictive Current Control Based Real and Reactive Power Control of Grid-Connected Hybrid Modular Multilevel Converter

<p>This paper proposes the grid application of modified three-phase topology of Modular Multilevel Converter (MMC) using finite-control-set predictive control. This topology has reduced number of switch counts compared to the conventional MMC, eliminates the problem of circulating current and having higher efficiency. A single dc source is required to produce sinusoidal outputs. The number of sub-modules (SMs) in this topology is half of the SMs required in case of MMC, in addition to a single H-bride circuit per phase. The finite-control-set predictive current control scheme for the grid connected dc source through the Hybrid Modular Multilevel Converter (HMMC). This controller controls the desired real and reactive power demand of the grid instantaneously. The simulation study of a three phase grid connected system has been done in Matlab/Simulink and the results are provided for the different real and reactive power demands, to validate the concepts.</p>

Modified modulation scheme for three‐level diode‐clamped matrix converter under unbalanced input conditions

The three-level diode-clamped matrix converter (TLDCMC) topology has outstanding performance under ideal operating conditions. However, input disturbance can influence the waveforms at the output side of the converter due to the direct coupling between the input and output. This study proposes a modified modulation scheme for TLDCMC during operation with unbalanced input voltages and when different transformer turns ratios are used for an isolation transformer at the input. With this modulation technique, sinusoidal and balanced output voltages are guaranteed and the input current harmonics are minimised. Experimental results are presented to demonstrate the feasibility and effectiveness of the proposed modulation scheme.

Direct Space Vector Modulated Matrix Converter

Matrix converter has emerged as a best substitution of the conventional converters due to the capability of power regeneration, the sinusoidal input and output waveforms, and no need for energy storage. MC is a single - stage converter having sinusoidal input as well as output voltage and current. It has an array of m X n bidirectional power switches to connect m - phase voltage source to an n - phase load. The main objective of the project is to generate and compare sinusoidal voltage using indirect space vector modulated more over direct modulated matrix converter for different power electronic applications. By this approach, we can reduce the complexity of Space vector modulated multilevel inverters. In order to explain about the proposed SVM technique, the switching configurations of matrix converter used in SVM techniques is assumed that the current and the voltage of MC are entirely constant within one sampling period.

A Single Phase AC/DC/AC Converter With Unified Ripple Power Decoupling

In single phase ac/dc/ac converters, the low frequency ripple powers exist both at the source and load sides. Usually, large dc-link filter components are used to buffer the ripple powers, which increases volume and weight. To overcome the drawback, this paper presents a single phase ac/dc/ac current source converter with unified ripple power decoupling. The converter only consists of three bridge arms and a decoupling circuit. The three bridge arms play the role of rectification and inversion with sharing a bridge arm. And the decoupling circuit is in series with the dc-link energy storage unit to buffer the ripple powers. The circuit configuration and operation principles are introduced first. Then, a modulation strategy based on Cartesian space is developed to achieve sinusoidal input and output currents. The control idea that the dc-link current is regulated by the decoupling circuit and the averaged decoupling capacitor voltage is maintained by the rectifier is adopted. The ripple power buffer is automatically achieved. Finally, the theoretical analysis is favorably verified by the simulations and experimental results.

Soft-Switching Solid-State Transformer (S4T)

This paper presents a new topology for a fully bidirectional soft-switching solid-state transformer (S4T). The minimal topology, featuring 12 main devices and a high-frequency transformer, does not use an intermediate dc voltage link, and provides sinusoidal input and output voltages. The S4T can be configured to interface with two- or multiterminal dc, single- or multiphase ac systems. An auxiliary resonant circuit creates zero-voltage-switching conditions for main devices from no-load to full-load, and helps manage interactions with circuit parasitic elements. The modularized structure allows series and/or parallel stacking of converter cells for high-voltage and high-power applications.

A Novel Approach of Controlling the Solar PV Integrated Hybrid Multilevel Inverter

The part of renewable energy systems like solar photovoltaic (PV) and wind power generation (WPG) is playing an energetic role in energy production. The power electronics technology growths have directed to the progresses in the solar power generation and solar PV sources have the potential to progress one of the key providers to the upcoming electricity. Lower voltage rating of solar PV systems requires a high voltage progress converter for parts grid associating with a DC-AC inverter. The solar energy acquired from the solar panel varies with times and solar irradiation. The boost DC/DC converter is used to sustain the constant output voltage achieved from the solar panel using MPPT algorithm and is operated according to the requirement. A 1-Ф cascade 13-level inverter is used to produce 13-level output voltage from the DC supply voltage achieved from PV panels. It offers better-quality sinusoidal output voltage and current waveforms and lower total harmonic distortion. In this paper, the proposed model is designed and the results are verified through simulation using MATLAB/SIMULINK tools

SVPWM for 3-phase 3-level Neutral Point Clamped Inverter Fed Induction Motor Control

<p>This paper gives Space Vector Pulse Width Modulation (SVPWM) for 3-phase 3-level Neutral Point Clamped (NPC) inverter fed induction motor control. A conventional two level inverter with 3-phase system has been developed for induction motor control. When it is applied for high voltage and power applications, which increases the voltage stress across the switch and harmonic content in the output. So multilevel inverter is much suitable for induction motor control, which provides nearly sinusoidal output voltage and diminished harmonic content in the output. Also the stator current of induction motor is minimsed, speed and torque of induction motor controlled with appropriate switching NPC inverter using SVPWM method. The proposed system simulation are verified using matlab simulink. </p>

A Novel Approach of Controlling the Solar PV Integrated Hybrid Multilevel Inverter

The part of renewable energy systems like solar photovoltaic (PV) and wind power generation (WPG) is playing an energetic role in energy production. The power electronics technology growths have directed to the progresses in the solar power generation and solar PV sources have the potential to progress one of the key providers to the upcoming electricity. Lower voltage rating of solar PV systems requires a high voltage progress converter for parts grid associating with a DC-AC inverter. The solar energy acquired from the solar panel varies with times and solar irradiation. The boost DC/DC converter is used to sustain the constant output voltage achieved from the solar panel using MPPT algorithm and is operated according to the requirement. A 1-Ф cascade 13-level inverter is used to produce 13-level output voltage from the DC supply voltage achieved from PV panels. It offers better-quality sinusoidal output voltage and current waveforms and lower total harmonic distortion. In this paper, the proposed model is designed and the results are verified through simulation using MATLAB/SIMULINK tools

Comparative Analysis of Various Z-source Based Five Level Cascaded H-bridge Multilevel Inverter

Z-source based multilevel inverters are the recent topologies as they have boosting ability and near sinusoidal output waveforms. This paper proposes different inverter topologies such as Z-source multilevel inverter and quasi Z-source multilevel inverter. This paper also deals with switched inductor and improved switched inductor topologies with quasi Z-network. The proposed switched inductor system reduces the voltage stresses caused by capacitors, power devices and diodes. In addition to multilevel inverter advantages, the proposed configuration employs Z-source inverter advantages. The Z-source inverter as compared to the traditional inverter is less costly, less complex, more efficient and more reliable. The performance of the proposed configurations is analysed by varying passive elements in impedance network and is simulated in MATLAB/SIMULINK. Phase disposition (PD) pulse width modulation (PWM) technique is applied on the proposed configurations and performance parameters are measured by the fast Fourier transform FFT analysis. The object of this paper is to develop an inverter which is used for variable speed drives with increase in output voltage by eliminating transformer and filter circuit. The performance is checked with standared parameter of the inverter.

A New Active Output Filter (AOF) for Variable Speed Constant Frequency (VSCF) Power System in Aerospace Applications

In this paper a new “active output filter” (AOF) for variable speed constant frequency (VSCF) power system in aerospace applications is proposed. The proposed AOF is envisioned as a power semiconductor filter block. In the proposed system the passive L-C output filter components are replaced by an H-bridge. The H-bridge is operated at high frequency to inject voltage harmonics to achieve a sinusoidal output voltage to the load. Advanced wide band gap devices can be employed in the design of AOF block to obtain high performance with simultaneous reduction in size. The proposed AOF concept offers a significant reduction in size/weight compared to passive L-C. Further, in the presence of AOF the main VSCF inverter can be operated in a six-step and/or at a reduced PWM frequency. An example 250 kVA, 3-phase 400-Hz system with the proposed AOF concept is evaluated via simulation with a corresponding passive L-C filter configuration. Experimental results on reduced kVA laboratory prototype are discussed.

Регулятор переменного напряжения с малым числом ключей и цифровым управлением

The paper considers a new three-phase AC voltage regulator with a few switches. The proposed converter is buck-boost with sinusoidal input and output currents. A calculating method of AC voltage regulator currents using the highest harmonics is proposed. Dependences of harmonic coefficients on the modulation depth were obtained using the ADE method, and the results were compared to the simulation results. The evaluation of the output and input currents quality relative to the switching frequency allowed choosing the optimal frequency range for the experimental layout. The digital control system of the AC voltage regulator with a small number of switches, which is based on the Atmel AVR Atmega microcontroller, was reviewed and analyzed. The paper also presents the diagrams of currents and voltages of the regulator with a digital control system obtained during the experiment.

Modelling of the Coupled Beam-Piezoelectric Material With Hysteresis Non-Linerity Effect

Hysteresis is one of the non-linearity characteristics of the piezoelectric material. This characteristic is important to be characterized since it can affect the performance of the piezoelectric material as sensor or actuator in many applications. In this study, the model of the coupled aluminium beam with single piezoelectric patch material is constructed to investigate the hysteresis effect of the piezoelectric material to the whole beam structure. A P-876 DuraActTM type piezoelectric patch material is used in modelling of the piezoelectric actuator. Firstly, the modal analysis of the coupled beam-piezoelectric actuator is determined to get the natural frequencies and mode shapes. Then, the piezoelectric patch material is investigated in terms of actuator by given a sinusoidal voltage excitation and output in terms of deflection, stress and strain of the piezoelectric actuator are investigated. From the results, it is clear that, the coupled beam-piezoelectric material is affected by the hysteresis of the piezoelectric material and the natural frequencies of the beam structure. This characteristic is important for the piezoelectric actuator manufacturer and by providing the correction algorithm, it can improve the performance of the piezoelectric actuator for many applications.

Magnetic Geared Radial Axis Vertical Wind Turbine for Low Velocity Regimes

In the 21st century, every country is seeking an alternative source of energy especially the renewable sources. There are considerable developments in the wind energy technology in recent years and in more particular on the vertical axis wind turbine (VAWT) as they are modular, less installation cost and portable in comparison with that of the horizontal axis wind turbine (HAWT) systems. The cut-in speed of a conventional wind turbine is 3.5 m/s to 5 m/s. Mechanical geared generators are commonly found in wind technology to step up power conversion to accommodate the needs of the generator. Wind turbine gearboxes suffer from overload problem and frequent maintenance in spite of the high torque density produced. However, an emerging alternative to gearing system is Magnetic Gear (MG) as it offers significant advantages such as free from maintenance and inherent overload protection. In this project, numerical analysis is done on designed magnetic gear greatly affects the performance of the generator in terms of voltage generation. Magnetic flux density is distributed evenly across the generator as seen from the uniform sinusoidal output waveform. Consequently, the interaction of the magnetic flux of the permanent magnets has shown no disturbance to the output of the generator as the voltage generated shows uniform waveform despite the rotational speed of the gears. The simulation is run at low wind speed and the results show that the generator starts generating a voltage of 240 V at a wind speed of 1.04 m/s. This shows great improvement in the operating capability of the wind turbine.

Crisscross switched multilevel inverter using cascaded semi‐half‐bridge cells

A new cascaded multilevel inverter (MLI) is presented with the aim of utilising lesser number of switches, better modularity and reduced voltage stress. The new structure configured under symmetric and asymmetric mode, produces all odd and even voltage levels. This structure comprises semi-half-bridge cells connected in series with crisscross switches to generate any target level for synthesising the sinusoidal output voltage waveform. In extension to the proposed topology, subinverters derived from the proposed MLI are cascaded with an objective to produce more voltage levels with reduced standing voltage. Compared with the cascading H-bridge topology, the proposed MLI and the extended version uses lesser number of semi-conductor switches. The MATLAB R2013b-based simulation results along with the experimental results validate the proposed topology.

A 13-Levels Module (K-Type) With Two DC Sources for Multilevel Inverters

This paper presents a new reconfiguration module for asymmetrical multilevel inverters in which the capacitors are used as the dc links to create the levels for staircase waveforms. This configuration of the multilevel converter makes a reduction in dc sources. On the other hand, it is possible to generate 13 levels with lower dc sources. The proposed module of the multilevel inverter generates 13 levels with two unequal dc sources (2 V DC and 1 V DC). It also involves two chargeable capacitors and 14 semiconductor switches. The capacitors are self-charging without any extra circuit. The lower number of components makes it desirable to be used in wide range of applications. The module is schematized as two back-to-back T-type inverters and some other switches around it. Also, it can be connected as a cascade modular which leads to a modular topology with more voltage levels at higher voltages. The proposed module makes the inherent creation of the negative voltage levels without any additional circuit (such as H-bridge circuit). Nearest level control switching modulation scheme is applied to achieve high-quality sinusoidal output voltage. Simulations are executed in MATLAB/Simulink and a prototype is implemented in the power electronics laboratory in which the simulation and experimental results show a good performance.

A Generalized and Flexible Control Scheme for Photovoltaic Grid-Tie Microinverters

In this paper, design and implementation of a flyback photovoltaic (PV) microinverter based on the direct digital synthesis (DDS) technique has been described for both the standalone and the grid-connected operation. The DDS technique adopted provides flexibility in the implementation of various control schemes of the PV microinverter on a simple low-cost digital signal processing type of microprocessor (dsPIC). As compared with the conventional look-up-table method used for generating sinusoidal output voltage waveforms by digital signal processing, a much higher resolution can be obtained in the voltage phase angle and magnitude owing to the adaptive nature of the look-up table implemented within the DDS architecture. The DDS technique is used in the implementation of all control schemes of a PV microinverter, such as maximum power point tracking (MPPT), phase-locked-loop (PLL), anti-islanding, and low-voltage ride-though (LVRT), with an integrated software run on a simple microcontroller. A dedicated computer simulation model is developed, where the PV panel model, the PLL in DQ reference frame, the MPPT algorithm, and the anti-islanding and LVRT features are all taken into account. The experimental results obtained on a 120-W PV flyback microinverter have verified the validity of the proposed technique for both the steady-state and the transient-state operation. The DDS technique is thus found to be quite convenient for application to module integrated converters.

Space vector pulse width modulation control techniques for a five‐phase quasi‐impedance source inverter

This study proposes space vector modulation (SVM) techniques for a five-phase quasi-impedance source inverter. Five different SVM methods are elaborated utilising four active neighbouring (from two different lengths group) and a zero space vector to synthesise the reference voltage with the aim of obtaining sinusoidal output voltage waveforms. The main objective of the developed SVM methods is to reduce total harmonic distortion (THD) in the output voltage waveform while simultaneously boosting the DC link voltage. Shoot-though period is computed according to the required boost in the DC voltage and spread in a switching cycle. Five different schemes are developed based on the shoot-through application in a number of inverter legs. A comprehensive comparative study of the proposed SVM techniques is carried out based on various obtained characteristics such as the shoot-through duty ratio, boost factor, voltage gain, THD and efficiency. Theoretical analysis and simulation results are validated using experimental approach.