Sinusoidal Output Voltage Research Articles

Sinusoidal inverter using pulse width amplitude modulation

In this paper, a technique of single-phase inverter pulse width-amplitude modulation is introduced. This technique is based on tap changer transformer that controls the amplitude of the output voltage. The DC voltage is applied on the primary side of the tap changer transformer with the help of a microcontroller through several semiconductor switches in sequential modality. The tap changer inverter has been analyzed, designed and simulated for four tap inverter using Proteus software. The LCL (low pass filter) is connected on the primary side of the transformer to generate sinusoidal output voltage. In hardware a tap changer inverter has been designed and implemented for four taps inverter. The microcontroller used is minipro, which produces command signal to the switches. The introduced topology has produced large number of levels with decreased total harmonics distortion (THD) in addition to a low cost with isolated multilevel inverter.

Voltage Modulation and Current Control of Boost Inverters for Stand-Alone or Grid-Tied Operation

Boost inverters can step up dc voltage and carry out dc-to-ac conversion by means of a differential output across two boost converters. Although the differential output is beneficial to reject the common-mode noise, the inconsistency in circuit parameters between the two converters may cause an inevitable dc component in ac current. In addition, since the voltage gain of the boost converter is in nonlinear correlation with the duty ratio, the control bandwidth required for input state and output state would disparate and make the control design difficult. To overcome the nonlinearity of the boost inverter, a passivity-based voltage modulator was presented to take the place of the modulator derived from the ideal voltage gain. While the input state (inductor current) is stabilized by the proposed modulator according to the desired output voltage and ac current, the remaining problem is the control of the dc-biased sinusoidal output voltage to meet the required ac current. The integration of a dc-component compensator, a proportional-resonant controller, and a voltage drop compensator were presented for achieving ac current regulation with a satisfactory response. To further refine the power efficiency of the boost inverter, the lower limit of the dc bias of the converter output voltage was considered. Experimental results show the effectiveness of the proposed approaches.

Robust Extended H∞ Control Strategy Using Linear Matrix Inequality Approach for Islanded Microgrid

This paper presents the design of an extended parameterisations of H ∞ controller for off grid operation of a microgrid. The microgrid consists of distributed generation units, filters and local loads. The filters are used to achieve accurate sinusoidal output voltage. However, loads which are connected to the microgrid are parametrically uncertain. Hence, it undergoes with unknown loads uncertainties. These unknown loads may create unknown loads harmonics, non-linearities which may reduce the voltage and current profile of the microgrid. As a result, the sudden rise and fall of voltage current profile damages the domestic and commercial loads. The proposed controller provides robust stability against various unknown loads and uncertainties. The design of the controller is presented using linear matrix inequality approach and satisfies the Lyapunov stability criterion. Moreover, it provides lower closed-loop H ∞ norm and has better tracking accuracy than other. For justification, several load conditions have been tested in MATLAB/SimPowerSystem Toolbox to ensure the robust stability of the proposed controller. All the results presented in the paper indicate high performance of the controller.

Аналіз енергетичних процесів у семирівневому автономному інверторі напруги при різних алгоритмах модуляції

The most commonly used in autonomous voltage inverter (AVI) is pulse-width modulation (PWM) and single modulation. The advantage of PWM prior to single modulation is the ability to control the amplitude of the first harmonic of the output voltage and, accordingly, the current required both for scalar and vector control of an asynchronous electric drive.Multilevel autonomous voltage inverters (MAVI) are finding increasing application in industry, namely: in wind and solar power engineering, high-voltage substations, in industrial and traction electric drives. In comparison with the classical two-level inverters, MAVI have several advantages: providing greater output power MAVI, the reduced value of the emission of higher harmonics in the load and the supply network, reduction of switching losses in semiconductor switches, which directly increases the efficiency, increased sinusoidal output voltage and current.Currently, there are several topologies of multilevel AVI, among which the most common are MAVI with fixing diodes, MAVI with convertible capacitors, MAVI with cascade half-bridge. Due to the fact that the MAVI with fixing diodes found the greatest use among the listed topologies, this article is dedicated to this type.The article examines the realizable quality parameters of the output voltage and output current in a seven-level AVI with fixing diodes during the implementation of various modulation algorithms. Methods for the implementation of PWM are considered. In Matlab / Simulink / SymPowerSystems, a seven-level AVI model has been developed with considered control systems. The results of simulation in the form of energy indicators, namely the harmonic distortion of the output current and voltage, are obtained.Results of studies of a multi-bridge active voltage-source rectifier in the interleaving mode are presented. Based on the energy balance equation were obtained relation that determine the adjusting characteristic of the output voltage in the rectification and recovery modes. Were developed Matlab models of active multi-bridge rectifiers with different number of parallel bridges and different PWM frequencies. It is established that interleaving in the active rectifier allows to significantly reduce the switching frequency of the input current. At the same time, it’s significantly reduces power losses in power switches and increases the efficiency of the active rectifier. Interleaving provides compensation of the higher harmonics of the input current. It is established that the coefficient of harmonic distortions of the output current in the mode of spatial - vector modulation is 3,71 %, and has a better index, in comparison with other modes of PWM. At the same time, lower power losses in AVI have a mode of inverted sinusoidal PWM and is 3849 W. As a result, with an increase in the number of AVI level, IGBT-transistors will also decrease losses.

A novel 49-level asymmetrical modular multilevel inverter: analysis, comparison and validation

High progresses in the field of power electronic create an appropriate bed to introduce new and upgraded multilevel inverter topologies. Such these topologies contain remarkable inherent advantages like: high quality staircase sinusoidal output voltage, low number of switches, low peak inverse voltage, et cetera. In this paper, a novel modular asymmetrical multilevel inverter is proposed to reduce the number of inverter’s components, and accordingly make a cost-effective structure with excellent voltage-step creation. In accordance with the configuration of utilized switches and magnetite of DC voltage source, the proposed structure can provide a high-step staircase sinusoidal voltage without high increase of semiconductors. Consider this; symmetrical condition of the proposed structure also takes low number of switches as compared to other symmetrical structures. Finally, both the MATLAB/SIMULINK and experimental results have confirmed the accurate operation and voltage-step creation capability of the suggested multilevel inverter.

Voltage-controlled of a three-phase current source inverter in islanded operation

This paper presents the performance of a three-phase current source inverter (CSI) in island mode voltage-controlled operation. Simple converter structure, low switching count and inherent boosting capability among the features offered by CSI. However, less investigation has been done with regards to the performance of CSI especially on its control system for island and grid-connected photovoltaic system. Thus, this study aims to investigate the suitability of proportional-integral (PI) and proportional-resonant (PR) control including their dynamic equations and state-space modeling. The results show that both controllers able to perform satisfactory in achieving zero steady-state error and balanced sinusoidal output voltage and current. PI control is superior in fast response time and excellent harmonic rejection than inverter using PR control PR control on the other hand, able to give more robust performance during imbalance occur than PI control due to individual control of the phases. This study may becomes one of the references with regard to current source inverter for early career researchers. as All results presented in this paper are verified with varying operational parameters in MATLAB/ SIMULINK platform.

Extended Range of Ultra Sparse Matrix Converter Using Integrated Switched Capacitor Network

Ultra sparse matrix converter (USMC) is known for ac-ac conversion with sinusoidal input currents, output voltages, and variable frequency operation. However, its operation is restricted for voltage gain up to 0.866 and load power factor angle up to 30° along with requirement of protection circuit for pulsating loads. This paper proposes switched capacitor USMC to overcome the restrictions of USMC with improved performance. Experimental results are provided to evaluate the converter capability and behavior under balanced and unbalanced input voltage conditions. Furthermore, the proposed converter is compared with the other counterparts.

THD minimization for Z-source-based inverters with a novel sinusoidal PWMswitching method

This paper presents a modified sinusoidal pulse width modulation (SPWM) switching method for one-phase and investigated two-phase impedance-source inverter structures. The proposed structure generates pulses for a quasi- Z-source converter and this block produces a unilateral voltage sine wave in the block's output. This signal is applied to the inverter as its input wave. For this purpose, the novel SPWM method is proposed for power switches while being switched complementarily. Two power switches are used in the structure to generate the pure sinusoidal output voltage and to minimize total harmonic distortion (THD), which is an essential parameter in inverter design. The results show that the proposed method generates the pure sinusoidal voltage and current signals for resistive and inductive loads and pure voltage and improved current waves for capacitive loads in comparison with existing techniques, since the THD of the output voltage and current signals is strongly affected by the dynamic loads. This method leads to final cost improvement and reduction of the size of the system with fewer number of components, which are essential parameters for renewable energy resource applications. A mathematical model is validated with the 2017a version of MATLAB/Simulink and 1.51% and 1.33% THD values are reported for low and high power loads, respectively, in the one-phase structure and 0.95% and 0.87% in the two-phase system. Finally, a 120 W prototype has been implemented and tested. A sine-wave with 620 Vac peak to peak amplitude and 50 Hz frequency has been gained in the inverter?s output and the quality of the voltage and current waveforms has been evaluated for different two 1.8 k$\Omega$ and 600 $\Omega$ resistive loads in the one-phase structure. Experimental results confirm all mathematical and simulation results.

A Novel Control DC-DC-AC Buck Converter for Single Phase Capacitor-Start-Run Induction Motor Drives

A novel control DC-DC-AC buck converter for single phase capacitor-start-run induction motor drives is presented in this paper. The objective is to minimize harmonic distortion in inverter output voltage supply to a Single Phase Induction Motor (SPIM). Here, the output of a variable duty cycle buck DC-DC converter is fed to an H-bridge inverter to generate a very close sinusoidal output voltage. Few power semiconductor switches are utilized to produce inverter output voltage with reduced harmonic distortion comparable with results achieved in multilevel inverters. The SPIM was analysed in the stationary d-q reference frame while the buck converter was operated in the Continuous Conduction Mode (CCM) to ensure that the output voltage vary exactly as the duty cycle. The simulation results show good starting transient characteristics for the SPIM and also stable operation under intermittent loading of 4 N-m. The average inverter output voltage of 157.4 V was achieved with Total Harmonic Distortion (THD) as low as 6.32%. This configuration is simple, cheap, and has reduced control complexity.

Elimination of Common Mode Voltage in Three-To-Six-Phase Matrix Converter

The matrix converter (MC) is the n-phase input and m-phase output power electronic system. To synthesis the controllable sinusoidal output voltage and input current with controllable input displacement angle, the pulse width modulation method (PWM) is used in the MC. During the modulation process a problem of the common mode voltage (CMV) exists. The elimination of the CMV in three-to-six-phase MC by usage of only rotating voltage space vectors is analyzed in the paper. The carrier based implementation of the space vector modulation (SVM) with Venturini modulation functions is applied to the control of the three-to-six-phase MC. Entire elimination of the CMV in three-to-six-phase MC is presented in the paper. The simulation and experiment results confirm utility of the proposed modulation method.

Design of a 100 kHz wide bandgap inverter for motor applications with active damped sine wave filter

In this study, a three-phase motor inverter with sinusoidal output voltages based on the application of gallium nitride transistors and advanced control is analysed. In comparison to standard silicon-insulated gate bipolar transistors much higher feasible switching frequencies of 100 kHz and above are possible and reduce the output sine filter component size such that the filter can be directly included into the inverter. This considerably improves the electromagnetic interference (EMI) behaviour of the drive system as well as the acoustic noise, eases the inverter-to-motor wiring and protects the motor isolation against high d u /d t rates. The study describes the dimensioning and design of the used two-stage LC filter including motor current control based on proportional-integral-type phase current controllers. The LC filter damping is performed actively by capacitor current feedback. Using this active damping scheme avoids additional losses of conventional sine filters and guarantees high system efficiency up to 98%. Finally, experimental results of a laboratory prototype verify the proper behaviour of the proposed concept.

New topology of a switched‐capacitor‐based multilevel inverter with a single DC power supply

The utilisation and importance of multilevel inverters, as one of the key component of new electrical systems, are ever-increasing. As a result, many works and evolutions have been carried out, which lead to improvements of topologies and control strategies. Newly introduced topologies can generate output voltage with maximum level number, minimum switching components and power supplies. This study introduces a multilevel inverter with minimum number of DC power supply and optimum number of semiconductors based on the switched-capacitor method. One of the best features of the proposed topology is its voltage generation with boost capability without any need for H-bridge. Moreover, the proposed topology has modular extension capability in order to increase the number of output levels. The comparison between the proposed converter and some previous topologies shows that it has better conditions with respect to the used semiconductor count, switches and capacitors losses. The operation and performance of the proposed multilevel converter have been ascertained through simulations and verified experimentally for a single-phase 17-level inverter. All results are illustrated to show the proposed converter's ability in smooth sinusoidal output voltage generation with boosting the input voltage without any transformer.

Lyapunov Energy Function Based Control Method for Three-Phase UPS Inverters With Output Voltage Feedback Loops

In this study, a Lyapunov energy function based control method with output voltage feedback loops is proposed for three-phase uninterruptible power supply (UPS) inverters. The presented paper demonstrates that the traditional Lyapunov-energy-function-based control method not only leads to considerable steady-state error in the output voltage, but also distorts the output voltage waveforms. Therefore, a modification has been performed on the traditional Lyapunov-energy-function-based control by incorporating the output voltage feedback loops in the control variables. The robustness of the proposed control method has been studied analytically through transfer functions which are expressed as the ratio of the output voltage to its reference. These analytical results are validated experimentally. In addition, the steady-state and dynamic performances of the proposed control method are also tested experimentally on a three-phase UPS inverter operating with linear (resistive) and nonlinear (diode-bridge rectifier) loads. As a consequence of incorporating output voltage feedback loops into the control variables, the proposed control method offers strong robustness against variations in LC filter parameters, high-quality sinusoidal output voltage along with acceptable total harmonic distortion (THD) values under linear and nonlinear loads, fast dynamic response under abrupt load changes, and negligibly small steady-state error in the output voltage.

Analysis and Design of a Single-Stage Bridgeless High-Frequency Resonant AC/AC Converter

A single-stage high-frequency resonant ac/ac converter converts the ac-line input voltage into the high-frequency sinusoidal output voltage, which consists of two power conversion units, i.e., a power factor correction (PFC) unit and a high-frequency resonant dc/ac unit, and it can be used to derive a modular multichannel constant current LED driver. By adopting a totem-pole bridgeless PFC boost rectifier to reduce conduction losses, a single-stage bridgeless high-frequency resonant ac/ac converter is proposed in this paper. The operating principle is described, and the performance analysis is presented in detail. Moreover, the quantitative parameter design method of the main circuit is presented, which is suitable for other single-stage ac input converters, such as a single-stage PFC rectifier. Finally, a 130-W prototype has been built and tested to verify the correction of related theoretical analysis and parameter design.

Seven‐level inverter with switched capacitors

The seven-level (7L) inverter with a nearly sinusoidal output voltage is suitable for renewable energy conversion applications. A novel 7L inverter topology with switched capacitors is proposed here. The topology is composed of an active clamping inverter and a switched-capacitor part in series connection. The switched-capacitor part, consisting of three switches and two clamped capacitors, can provide 1/3 or 2/3 level of output voltage. By connecting switched-capacitor part in forward or backward series to the inverter output, a 7L output voltage waveform can be obtained with enough redundancy switching states to balance the voltage of switching capacitors. A modified modulation method is also proposed to make the topology operating properly. The voltage of switched-capacitor part can be sustained E and 2E alternately by adjusting a modulation index according to the capacitor voltage and load current. The effectiveness of the proposed topology is validated by both simulative and experimental results. Comparing with conventional 7L inverter topology, less number of devices were adopted in the proposed topology with a simple and practicable modulation method.

Integrating multilevel converters application on renewable energy sources—A survey

Multilevel inverters emerged as the solution for overcoming the limitations of two level inverters, such as total harmonic distortion, high magnetic interference, and high dv/dt in high power voltage applications. The ability to generate sinusoidal output voltage is another speciality of multilevel inverters. The wide range of applications in fields such as power grids, motor drives, and Volt-Ampere Reactive compensation enhances the visibility of multilevel inverters. This paper identifies the conventional multilevel inverter topologies such as diode clamped multilevel inverters, flying capacitor multilevel inverters, and cascaded H bridges and presents a literature review on the topologies considering the facts of structural and functional diversities over the ages which have been adapted right from the beginning of its emergence. It also details the various optimization technologies that are used in multilevel inverters to obtain the optimal switching angle for harmonic elimination. This paper also explains the modulation techniques that are in effect for a specific purpose in different applications to get the best possible result.

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 spacevector pulse width modulation technique with a three segment switching sequence and seven segment switching sequence for high power applications of multilevel inverters. In the proposed method, the inverter switching sequences are optimized for minimization of device switching frequency and improvement of harmonic spectrum by using the three most desired switching states and one suitable redundant state for each space vector. The proposed three-segment sequence is compared with conventional seven-segment sequence 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, current and line voltage THD, thereby minimizing the filter size requirement of the inverter, employed in industrial applications, where sinusoidal output voltage is required.

Design and Simulation of Novel 11-level Inverter Scheme with Reduced Switches

This work recommends the performance of coupled inductor based novel 11-level inverter with reduced number of switches. The inverter which engender the sinusoidal output voltage by the use of split inductor with minimised total harmonic distortion (THD). The voltage stress on each controlled switching devices, capacitor balancing and switching losses can be reduced. The proposed system which gives better controlled output current and improved output voltage with moderate THD value. The switching devices of the system are controlled by using multicarrier sinusoidal pulse width modulation algorithm by comparing the carrier signals with sinusoidal signal. The simulation and experimental results of the proposed 11-level inverter system outputs are established using matlab/Simulink and dsPIC microcontroller respectively.<br /><br />

Hierarchical Distributed Balancing Control for Large-Scale Reconfigurable AC Battery Packs

This paper presents a hierarchical balancing algorithm for use in large-scale reconfigurable ac battery packs. Using a decentralized battery management system, the pack is organized in control layers with each layer controller responsible for a small number of slave controllers, thereby significantly reducing communication and centralized processing requirements. The hierarchical balancing algorithm uses all available voltage steps in the pack ensuring a high-quality sinusoidal output voltage while balancing the objects of different layers. Balancing priority can be swapped dynamically between layers according to the maximum state of charge (SoC) variation between the objects of each layer while also ensuring that the output voltage reference is always met even when a cell failure occurs, as long as there are an adequate number of cells available in the pack. An experimental demonstration of the proposed balancing algorithm is presented using an ac battery pack comprising 144 20-Ah lithium-titanate cells. Cell balancing to within 2 mV of the cell open-circuit voltage is achieved between cells with 20% initial SoC variation and 5% capacity difference.

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>