Sinusoidal Output Research Articles

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.

Design and digital implementation of power control strategy for grid connected photovoltaic inverter

<p class="Abstract">This paper presents the optimization design and a detailed implementation in FPGA (Field-Programmable Gate Array) of a power control strategy. This strategy is based on the phase shift angle of the inverter output voltage with respect to the grid voltage and DSPWM (Digital Sinusoidal Pulse Width Modulation) patterns “Phase shift angle-DSPWM” for an inverter for photovoltaic system connected to the grid. The proposed control can synchronize a sinusoidal inverter output current with a grid voltage and control the power injected into the grid. Detailed development of a digital controller with lower hardware and computation requirement is proposed. Description on the digital implementation of the A/D converter, the PI compensator, the phase shift and the DPWM, is provided. This digital control exhibit simplicity, reduction of the memory requirements and power calculation for the control. The functional structure of this system with digital control has been validated with simulations and experimental results.</p>

Study of the operation optical power in modified uni-traveling carrier photodetector for low amplitude to phase conversion

The phase noise known as the amplitude to phase conversion (AM–PM) in modified uni-traveling carrier photodetector (MUTC-PD) is severely power-dependent. To achieve low AM–PM operation, applying proper injection optical power will be of crucial importance. For this purpose, the characterization of the phase change between the 60-GHz sinusoidal input and RF output of a MUTC-PD is analyzed under different incident optical power. Moreover, the equation of the phase change is deduced by applying an equivalent circuit model. The results demonstrate that the power-dependent nonlinear transit time plays a key role in the phase change. Besides, the absolute phase change is observed smallest when the differential capacitance equals to zero in a typical optical power. To the best of our knowledge, this is the first demonstration of the relationship between the differential capacitance and the phase change. When the differential capacitance equals to zero, the total capacitance of the MUTC exhibits a valley which could be a measurable feature of the optimum optical power for low phase noise operation.

Parallel Operation of Current-Source Inverter for Low-Voltage High-Current Grid-Connected Photovoltaic System

Solar energy is very potential to be developed in a tropical country such as in Indonesia. This energy source is eco-friendly because it can eliminate air pollution such as caused by conventional fossil fuels. This research article presents analysis results of a novel grid-connected photovoltaic system using low-voltage high-current system. The electrical energy produced by the photovoltaic system was sent into the electrical power grid using two or more H-bridge current source inverters operated in parallel. The proposed system is very suitable for large size photovoltaic system because of its some merits. The inverter circuits work generating sinusoidal output currents and controlling the power delivered into the grid. The test results of the new system showed that the system worked properly as interface between photovoltaic system and the electrical grid delivering high ac current with low harmonic distortion.

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 proposed single-stage single-phase full bridge boost inverter

ABSTRACTA proposed topology for a high-efficiency single-stage single-Phase boost inverter with a simple circuit configuration and a low component count is proposed in this paper. The proposed inverter produces instantaneous output voltages higher than the input dc voltage without an intermediate power conversion stage. A new control scheme is designed that enables the proposed inverter topology to produce a low distortion sinusoidal output waveforms and provide good load voltage regulation. The inverter circuit topology and modes of operations are fully described and simulated using Matlab/Simulink. The simulation results are presented illustrating the claimed boosting characteristics, sinusoidal output wave forms and good load regulation capability of the proposed inverter. The validity and effectiveness of the proposed inverter are verified experimentally by building a laboratory model using the digital signal processor (Model DS1104). The experimental results are presented confirming the claimed features of the inverter.

Space vector PWM algorithm for a three‐level asymmetrical six‐phase motor drive

A space vector pulse-width modulation (SVPWM) algorithm for a three-level asymmetrical six-phase drive based on vector space decomposition (VSD) approach is presented in this paper. A modification in zero plane of the transformation matrix is proposed in order to meet the requirement that the realisation of sinusoidal output phase voltages can be obtained through the chosen output leg voltage space vectors. Furthermore, a method of choosing the switching sequences based on all possible one-level transitions of the leg voltages, i.e. a permutation method, is introduced. The algorithm is then validated experimentally and obtained results show that the developed method successfully achieves the desired fundamental phase voltage, although low order harmonics are present due to uncompensated inverter dead time. Last but not least, the performance of the proposed SVPWM algorithm is compared to several carrier-based PWM algorithms including in-phase disposition with ‘double min-max injection’ (PD-DI). This is a little known type of injection, which is verified to obtain identical performance as the presented multilevel algorithm.

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.

Carrier‐based PWM control strategy for three‐level indirect matrix converter

This article proposes a new carrier-based pulse width modulation (CBPWM) strategy for the control of TLIMC. The duty ratios of the rectifier stage and inverter stage are calculated by the SVPWM method. A carrier is constructed and combined with duty ratios to obtain modulation waves, which are regular and determined by the input voltage and output reference voltage. Then, the modulation waves are compared with the same carrier to obtain pulse signals. The pulse signals are used to produce driving signals of power switches through logic operation. The rectifier stage and inverter stage are controlled by the driving signals to obtain three-phase symmetrical sinusoidal input and output waveforms. The proposed method is identical in output to the original SVPWM method. Finally, simulation and experimental results are provided to verify the feasibility and validity of the proposed method.

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.

Characteristics of magnetic sensor with assembly errors in a rotary recording system

A magnetic position sensing system consists of a magnetic rotary ring with polarities magnetized on its radial surface and a position sensor made of magnetoresistance. Two quadrature sinusoidal output signals from sensor are processed into position information for motion control application. Magnetoresistance varies with the angle between magnetization (M) of external field and flow current (I) inside the sensor patterns. Therefore, the assembly error either in sensor or rotary ring would cause distorted signal. The assembly error between sensor and the medium such as offset, pitch, roll, yaw error and eccentricity between scale and stage of motion centre of read head would be discussed in this paper. Experimental and analytical parameter studies were conducted in this paper to discuss the accuracy error and variation of output quadrature signal caused by assembly error. Through the parameter studies, the data under various conditions can then be used to serve as a baseline.

Signal Error Detection and Correction of Quadrature Detectors of Laser Interferometers

Errors of laser interferometers using quadrature detectors depend not only on the interferometers themselves, but also on the electronic systems for processing quadrature signals. There are three sources of errors of quadrature detector signals that affect the displacement measurement error: the inequality of the amplitudes of quadrature signals, the phase shift of these signals (not equal to 90°), and the zero offset in each signal. A simple method for identifying and correcting these errors based on experimental data on signals obtained using analog-to-digital converters is considered. The proposed method is applicable to any interferometer with sinusoidal quadrature outputs.

Photovoltaic AC Module Based on a Cuk Converter With a Switched-Inductor Structure

The development of a photovoltaic ac module composed of a high static gain nonisolated dc–dc converter with current source output characteristic followed by an unfolding low-frequency inverter is presented in this paper. The operation of the dc–dc converter with high static gain and with reduced switch voltage is obtained using the Cuk converter integrated with the switched-inductor technique. The nonisolated structure allows the elimination of the volume and losses of the power transformer and leakage inductance, and an output filter configuration is proposed to reduce the high-frequency ground leakage current. The grid-tied inverter operating in a discontinuous conduction mode (DCM) allows a sinusoidal output current with low harmonic distortion (THD = 3.72%) to be obtained without current control loop and without the use of a current sensor at the output. The maximum power point tracking operation is obtained without the use of the current sensor. The DCM operation increases the current stress, but the proposed converter presents two switches and two input inductors sharing the input current in these components. The theoretical analysis, design procedure, and experimental results are presented for a prototype with a dc input voltage Vi = 30 V, an ac output voltage Vo = 127 V, and output power Po = 180 W.

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.

Manitoba Inverter—Single-Phase Single-Stage Buck-Boost VSI Topology

The paper presents a new transformerless single-phase single-stage buck–boost grid-connected voltage source inverter (VSI) topology. The topology can achieve efficient power conversion with a wide input voltage range, number of magnetic devices reduction and low leakage current. The proposed VSI topology consists of high frequency semiconductors for shaping inductor currents, and low frequency semiconductors to form grid CL filter structure for different conditions. This CL filter uses the same buck–boost inductor, thus no additional line frequency inductor is required. Besides, common mode voltage, a main problem of transformerless grid-connected VSI, is mitigated, since the capacitor in the CL filter clamps the voltage between the grid and the bus terminal. The performance of the proposed VSI is experimentally verified. The results show that the proposed VSI guarantees sinusoidal output current and wide input voltage range, and has a good agreement with the theoretical findings.

Improved Operation Strategy with Alternative Control Targets for Voltage Source Converter under Harmonically Distorted Grid Considering Inter-Harmonics

This paper proposed an improved control method for grid-connected voltage source converter (VSC), when the grid voltage consisted of the integer harmonics and inter-harmonics. Control object of the proposed control can be alternated to achieve the sinusoidal current or smooth output power, which enhances the operation adaption of VSC under the harmonically distorted grid. On the basis of a PI regulator in the fundamental current control loop, the novel control strategy was proposed with a supplementary controller which consisted of a prepositive high-pass filter and a modified proportional-derivative controller. In the proposed control, the inter-harmonics could be suppressed without detecting frequency, while the traditional resonator was effective in the premise of knowing the harmonics frequency. Also, the influence of control gain on the steady performance and the stability of VSC was analyzed, and the influences on the fundamental control caused by the proposed controller were also analyzed to verify the practicability of the proposed control strategy. Finally, the effectiveness of the proposed strategy was verified by the experiments.

Application of deconvolution to recover frequency-domain multiplexed detector pulses

Multiplexing of radiation detectors reduces the number of readout channels, which in turn reduces the number of digitizer input channels for data acquisition. We recently demonstrated frequency domain multiplexing (FDM) of pulse mode radiation detectors using a resonator that converts the detector signal into a damped sinusoid by convolution. The detectors were given unique "tags" by the oscillation frequency of each resonator. The charge collected and the time-of-arrival of the detector pulse were estimated from the corresponding resonator output in the frequency domain. In this paper, we demonstrate a new method to recover the detector pulse from the damped sinusoidal output by deconvolution. Deconvolution converts the frequency-encoded detector signal back to the original detector pulse. We have developed a new prototype FDM system to multiplex organic scintillators based on convolution and deconvolution. Using the new prototype, the charge collected under the anode pulse can be estimated from the recovered pulse with an uncertainty of about 4.4 keVee (keV electron equivalent). The time-of-arrival can be estimated from the recovered pulse with an uncertainty of about 102 ps. We also used a CeBr3 inorganic scintillator to measure the Cs-137 gamma spectrum using the recovered pulses and found a standard deviation of 13.8 keV at 662 keV compared to a standard deviation of 13.5 keV when the original pulses were used. Coincidence measurements with Na-22 using the deconvolved pulses resulted in a timing uncertainty of 617 ps compared to an uncertainty of 603 ps using the original pulses. Pulse shape discrimination was also performed using Cf-252 source and EJ-309 organic scintillator pulses recovered by deconvolution. A figure of merit value of 1.08 was observed when the recovered pulses were used compared to 1.2 for the original pulses.

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.

Mitigation of DC Current Injection in Transformer-Less Grid-Connected Inverters Using a Voltage Filtering DC Extraction Approach

Transformer-less grid-connected PV inverters are an attractive technology choice due to their high-efficiency performance and relatively small volume. However, in the absence of galvanic isolation, dc current can potentially flow into the grid and adversely affect the grid performance. In addition, as the sinusoidal ac output is significantly larger than the dc injection component, accurate dc current sensing at the inverter output remains a technical challenge. As a result, this paper proposes a two-stage dc voltage detection technique that employs an isolated RC attenuation circuit and a software dc-component filtering algorithm. The principle of the proposed technique can be applied in many switch-mode power converter topologies. The simple and cost-effective combination facilitates dc component extraction within the accuracy of 1 mV; moreover, this can be further used as digital dc feedback for active current control purposes. Experimental results from a laboratory prototype demonstrate the high performance of the proposed dc extraction and suppression approach.