Sine Wave Output Research Articles

Design, Fabrication and Implementation of A Modified 1kVA Sine Wave Solar Power Inverter

The aim of this paper is to fill a niche which seems to be lacking in the power inverters market, one for a fairly efficient, inexpensive inverter with a pure sine wave output. Utilizing PWM and analog components, the output will be a clean sinusoid, with very little switching noise, combined with the inexpensive manufacturing that comes with an analog approach.

Scaling of mode shapes from operational modal analysis using harmonic forces

This paper presents a new method for scaling mode shapes obtained by means of operational modal analysis. The method is capable of scaling mode shapes on any structure, also structures with closely coupled modes, and the method can be used in the presence of ambient vibration from traffic or wind loads, etc. Harmonic excitation can be relatively easily accomplished by using general-purpose actuators, also for force levels necessary for driving large structures such as bridges and highrise buildings. The signal processing necessary for mode shape scaling by the proposed method is simple and the method can easily be implemented in most measurement systems capable of generating a sine wave output. The tests necessary to scale the modes are short compared to typical operational modal analysis test time. The proposed method is thus easy to apply and inexpensive relative to some other methods for scaling mode shapes that are available in literature. Although it is not necessary per se, we propose to excite the structure at, or close to, the eigenfrequencies of the modes to be scaled, since this provides better signal-to-noise ratio in the response sensors, thus permitting the use of smaller actuators. An extensive experimental activity on a real structure was carried out and the results reported demonstrate the feasibility and accuracy of the proposed method. Since the method utilizes harmonic excitation for the mode shape scaling, we propose to call the method OMAH.

Cascaded Symmetric Multilevel Inverter with Reduced Number of Controlled Switches

Multilevel inverters have become popular among high power converters for the past few years due to their high quality output waveform and low total harmonic distortions (THD). In addition, the filter size also reduces significantly to achieve a pure sine wave output. Cascaded H-Bridge topology has been recognized as the most promising among various classical topologies for multi-level inverters on the basis of its modular form and ease of design, troubleshooting, packaging and high power capabilities. However, a large number of switches are required in cascaded H-Bridge multilevel inverter that leads to larger system losses and an increase in cost. In this paper the modified cascaded topology is proposed to reduce the number of controlled switches without affecting the resolution of output waveform or the number of voltage levels. We achieved this by replacing some of the high cost controlled transistor switches with diodes, in the cascaded H-Bridges. Furthermore, equal voltage source sharing is also possible by using the proposed topology. Hence the proposed inverter is a type of cascaded multilevel inverter with reduced switches, better modular structure, low cost and high efficiency. The inverter design is validated using simulations and tested on hardware prototype.

Multiphase resonant inverter with sine wave output voltage

Methods to obtain the sinusoidal output voltage in DC-AC converters are considered. Large switching losses in power switches, high frequency interference, and the relatively high cost are the major disadvantages of DC-AC converters with pulse-width modulation. The circuit of a multiphase parallel resonant inverter with a pure sine wave output voltage is proposed. The operating principle of the two-phase inverter and the method of output voltage control are described. The results of resonant inverters OrCAD simulation are shown. The advantages of the proposed inverter circuit are shown in comparison with a single-phase circuit.

Моделирование самообучающейся системы управления инвертором преобразователя частоты для подавления высших гармоник

Simulation of a three-phase frequency converter based on three single-phase full-bridge voltage inverters with a sine-wave output filter is considered. A new self-learning control system for the converter’s inverters is proposed. The previously developed inverter control system uses the discrete Fourier transform (DFT) to suppress the output voltage higher harmonic components. Individual regulators are used to control each harmonic component (including the fundamental and higher-order ones). The DFT algorithm produces signals proportional to the amplitudes of the fundamental and a number of higher-order harmonic components, which are applied to the regulators as feedbacks. The main drawback of the existing system is that it poses rather high demand to the microcontroller computation capacities. The newly proposed system is based on the self-learning principle and uses a periodic integrator (a P-integrator) as the output voltage regulator. The P-integrator is represented in discrete form by an array of discrete integrators, each of which operates only in the 1/64 part of the fundamental harmonic component cycle. The new control system's software code is much smaller in size and contains a fewer number of “slow” arithmetic operations, due to which it is easier to implement and less demanding with respect to computation resources. The control system analysis results demonstrate its good performance in terms of suppressing higher harmonic components: the output voltage total harmonic distortion factor does not exceed 5% for the cases of operation on linear and nonlinear loads. The article describes the modernized control system structure and its implementation in MATLAB Simulink software package. Advantages of the self-learning algorithm as compared with the algorithm based on the discrete Fourier transform are demonstrated. The simulation results confirm the applicability of the new control method. The algorithm is implemented in the C language in the MATLAB S-function block and is suitable for being implemented in real-time control systems based on dedicated microcontrollers without the need of significantly modifying the software code.

A 2-15 GHz VCO With Harmonic Cancellation for Wide-Band Systems

A 2-15 GHz SiGe VCO (voltage controlled oscillator) has been developed with a very low harmonic content. The design is based on the harmonic cancellation concept and uses a multiple-phase ring oscillator together with a wide-band active-weighted summer. The VCO results in an output power of −8 to −6 dBm and $3^{rd}$ and $5^{th}$ harmonic level at 2-15 GHz. The active area of the chip is very small ( $0.67 \times 0.25$ mm2) due to the lack of inductors, and the power consumption is 88-120 mW from a 2.5 V supply. To our knowledge, this is the first demonstration of a wide-band VCO showing a near-perfect sinewave output over a wide frequency range. The application areas are in built-in-self-test sources for wide-band radios and phased arrays.

A Real-Time Harmonic Detection Method for Single-Phase Active Power Filters

Abstract: Harmonics, due to the increasing use of nonlinear loads, such as converters and solid state switching devices, has become a serious problem in power systems. Active power filters (APFs) have been used effectively to eliminate harmonic components. Precision of harmonic detection is one of the most important factors of APFs. This paper describes a novel circuit is proposed for real-time harmonic detection as an alternative to conventional approaches. This circuit is based on a switched capacitor band-pass filter and a Phase Locked Loop (PLL) which has low distortion sine wave output. This PLL follows not only phase of reference signal but also its amplitude. Harmonic components have been obtained by subtracting produced fundamental component with PLL from distorted signal. Fundamental and harmonic components of distorted line voltage and current have been successfully separated experimentally.

Electromechanical modeling and designing of capacitive MEMS DC/AC interactive power inverter for renewable energy applications

This paper presents the electromechanical modeling and designing of a new concept micro-scale DC/AC interactive power inverter for renewable energy applications. The proposed power inverter is based on micro electromechanical systems (MEMS) technology to compete with commercial power electronics inverters, in terms of size miniaturization, generating pure and smooth sine wave output, efficiently regulating the frequency of output signal, consuming ultra low power, and sufficiently low cost. The proposed MEMS power inverter occupies an active layout area of 35 × 35 mm2, with 455 µm thickness. It has a 50 Hz mechanical resonance frequency, and a 3.9 pF initial capacitance. The anticipated MEMS power inverter is capable of converting DC voltages, as low as 0.5 V from a single solar cell, or as higher voltage as 24 V from a photovoltaic module. The capacitive design concept of the proposed MEMS power inverter leads to zero power consumption. The frequency and waveform shape of the converted DC/AC signal matches with the AC signal of a power grid, with 6 % observed conversion efficiency.

Power Loss, System Efficiency, and Leakage Current Comparison Between Si IGBT VFD and SiC FET VFD With Various Filtering Options

SiC devices are gaining acceptance in the motor drive industry. This paper compares the power loss and efficiency between two options that can be used with SiC-based variablefrequency drives (VFDs). In the first option, the SiC VFD is equipped with an output sine-wave filter with carrier frequency at 50 kHz. A $dv/dt$ filter is used for the second option with the carrier frequency reduced to 8 kHz. Both options are compared with a standard Si insulated-gate bipolar transistor (IGBT) VFD operating at a carrier frequency of 8 kHz with no output filter. The focus of this paper is to present different filtering options for SiC VFDs. The $dv/dt$ filter is designed to meet the same specification as that of the standard Si IGBT VFD with no output filter, so as to present a fair comparison between a standard Si IGBT VFD and the next-generation SiC VFD. Results using a 460-V 11-kW system show that the SiC VFD with an output sine-wave filter has a lower efficiency compared with SiC VFD with a $dv/dt$ filter. Influence of the various filtering options on leakage current in the motor drive system has also been studied, and the results are presented in this paper.

3-D Space Vector Modulation Algorithm for Multilevel Inverters in Abc Coordinates for Solar PV Applications

Solar PV based Power generation is gaining importance in the present scenario of energy crisis. Precise control of Solar PV inverter is a very important factor deciding the efficiency and performance of Solar PV sources. Space Vector Modulation (SVM) technique is widely used for pulse width modulation in inverters, especially for power supplies for obtaining improved sine wave output. It is based on the representation of the three phase quantities as vectors in a two-dimensional using α and β co-ordinates. Here, a new three–dimensional (3-D) space vector algorithm in a-b-c co-ordinates for multilevel inverters is presented, which is based on the 3-Dimensional geometry of the vectors. This method calculates the on-state duration of switching vector without involving trigonometric functions, look-up tables or coordinate system transformation. Hence the computational complexity is very less compared to other algorithms. The proposed scheme is explained for a multilevel inverter and simulation results are presented with comparison of performance of a two level inverter and a three level inverter using this technique. The results shows that the algorithm can be applied for higher level inverter so that it operates at reduced Total Harmonic distortion.

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.

Prediction-based Deadbeat Control for Grid-connected Inverter with L-filter and LCL-filter

—In this article, an improved deadbeat control algorithm suitable for digital signal processor-based circuit implementation is proposed. The control algorithm allows the derivation of a nearly sine wave output current with a fixed switching frequency of a current-controlled voltage source inverter. Two low-pass output filters configurations are considered in this study: a simple inductance filter and an LCL-filter. By taking advantage of prior knowledge of the state variables’ shape, the improved deadbeat control algorithm is based on a simple prediction model to derive the expected duty cycle needed to switch on and off the power switches. The control study of the grid-connected inverter with L and LCL output filters has been considered using a co-simulation approach with (Powersim Inc., Rockville, Maryland, USA) and MATLAB software (The MathWorks, Natick, Massachusetts, USA). The obtained results show the improvement of both shape quality and tracking accuracy of the output current quantified by low ripple content and a nearly unity power factor.

Battery‐powered portable instrument system for single‐cell trapping, impedance measurements, and modeling analyses

A battery-powered portable instrument system for the single-HeLa-cell trapping and analyses is developed. A method of alternating current electrothermal (ACET) and DEP are employed for the cell trapping and the method of impedance spectroscopy is employed for cell characterizations. The proposed instrument (160mm × 170mm × 110mm, 1269g) equips with a highly efficient energy-saving design that promises approximately 120 h of use. It includes an impedance analyzer performing an excitation voltage of 0.2-2 Vpp and a frequency sweep of 11-101 kHz, function generator with the sine wave output at an operating voltage of 1-50 Vpp with a frequency of 4-12 MHz, cell-trapping biochip, microscope, and input/output interface. The biochip for the single cell trapping is designed and simulated based on a combination of ACET and DEP forces. In order to improve measurement accuracy, the curve fitting method is adopted to calibrate the proposed impedance spectroscopy. Measurement results from the proposed system are compared with results from a precision impedance analyzer. The trapped cell can be modeled for numerical analyses. Many advantages are offered in the proposed instrument such as the small volume, real-time monitoring, rapid analysis, low cost, low-power consumption, and portable application.

Colpitts Oscillator: Design and Performance Optimization

From the very fundamental oscillator, a simple pendulum wherein there is a constant energy switch between potential and kinetic energy, oscillators have seen groundbreaking changes in setup, operation and their applicability. There are harmonic oscillators which produce a continuous sine wave output of certain frequencies as per the passive components involved. Additionally, are knownRelaxation oscillator which yield triangular, square and sawtooth waves as output to name a few.The present paper deals with the details of how a fundamental Colpitts oscillatory circuit can be designed. Furthermore, we would take a look at optimizing its performance with change in several dependent characteristics in oscillation. We would conclude with an inference pertaining to the best customization with could be put to practical usage.

Efficiency Comparison Between Si-IGBT-Based Drive and GaN-Based Drive

High motor efficiency, lower torque ripple, close to ideal sinusoidal motor current waveform, smaller filter size, etc. are a few of the advantages of using high-frequency pulsewidth modulaton (PWM) (in the range of 50 to 100 kHz) in motor drive applications. However, higher frequency PWM is also associated with voltage reflection and motor insulation breakdown issues. Due to high losses, Si IGBT-based inverters cannot be operated at high switching frequency. Work on SiC and GaN-based inverter has progressed and variable-frequency drives (VFDs) can now be operated efficiently at carrier frequencies in the 50 to 200 kHz range, using these devices because of extremely low turn-on and turn-off losses. At high frequency, physical and electrical rating of output filter reduces, thereby improving efficiency. Loss in ac motors also reduces because of sinusoidal waveform. All the above features put together improves system efficiency. This paper focuses on comparing the efficiency of Si-IGBT-based drive with a 6-in-1 GaN module-based drive, which is operating at a carrier frequency of 100 kHz with an output sine wave filter. Experimental results show the GaN-based drive has a better system efficiency compared to the standard Si IGBT-based drive.

An Improved Variable-Frequency Drive Based on Current Tracking

Variable frequency devices are widely used in many power systems. A current tracking based VFD is proposed in this paper. The output current is firstly fed back and compared with a standard sine wave, the difference of them is then used for a PI regulator to control the PWM signal, so as to change the output current accordingly to make it approach the standard sine wave. Simulation and experiments results show that the current tracking VFD not only has a fast dynamic response, high current tracking precision, current limiting ability, but also has small distortion of the output sine wave current and low loss of the motor. DOI: http://dx.doi.org/10.11591/telkomnika.v11i11.3508 Full Text: PDF

Laddered multilevel DC/AC inverters used in Solar Panel Energy systems

Multilevel DC/AC inverters have various structures. They have many advantages. Unfortunately, most existing inverters content too many components (independent/floating batteries/sources, diodes, capacitors and switches). The author introduces the ‘laddered multilevel DC/AC inverters’ in this study, that is new approach of the development in this area. These inverters use much less components. Their simple structure and clear operation are obviously different from the existing inverters. Its application in Solar Panel Energy systems is successful. The simulation and experimental results strongly support our design. The measured total harmonic distortion illustrates the good quality of output sine wave. The authors believe that these inverters will draw much attention, and be applied in other renewable energy systems.

Harmonic Mitigation Using Single Phase Shunt Active Power Filter With Fuzzy Logic Controller for the Improvement of Power Quality

Abstract Due to the proliferation of non-linear modern power electronics, currents and voltages produced by non-linear loads have lead to the deterioration and distortion of the output sine wave forms of the source currents and voltages. These distortions have resulted in the power quality problems. The non-linear load draws reactive power and harmonics from the ac source in the fundamental current. The harmonics in power system caused by non-linear loads such as, arc furnaces, switch mode power supply, fluorescent lamps rectifiers etc all are the main sources of harmonics, as a result of these non-linear loads the supply system lead to overheating of cables and conductors, electromagnetic interference to nearby communication facilities etc. Therefore, as a result of theses harmonics, a traditional passive filters are used to suppressed the integer multiple fundamental frequencies, but due to the passive filter draws back in producing series or parallel impedance with the supply impedance and heavy in sized, its limitations in service becomes an old scheme. The application of shunt active power filter in mitigating these harmonics problems supersedes the used of passive filter. This paper, presents the modeling and simulation of single-phase shunt active power filter controlled with fuzzy logic controller (FLC) to mitigate the harmonics drawn by non-linear loads. The proposed scheme is performed by using MATLAB fuzzy tool box environment. Simulation results obtained by the proposed control algorithm found to be satisfied and within the recommended imposed IEEE 519-1992 harmonic standard limit.

Studies on the operation of trap filters and oscillators systems based on ceramic resonators at the cryogenic temperatures

We investigated the temperature dependence of the applications of piezo PZT ceramic resonators down to 93K in oscillators and filters circuits inside a frequency range of 400kHz–4.0MHz. For both systems, their waveforms were plotted at different temperature values ranging from room level (293K) down to (93K). From which, it is clearly shown that, cryogenic temperature effect on the operation of the trap filter system was shown to increase the voltage value at stop-band from 1.40V, measured at 293K, up to 4.40V. The rise and fall times of the square wave oscillator were shown to increase slightly with temperature decreasing. Initial values of 92.3ns, and 85.8ns, measured at 293K, were observed to increase up to 106ns and 107ns, measured at 93K, respectively, while the signal output was kept constant. But for the sine-wave oscillator, its frequency, and output voltage were shown decrease as the temperature decreases

A Variable Frequency and Variable Phase Function Generator with Dual Outputs

A Function generator with two outputs is described. As it is common with any function generator, the two outputs can be independently configured to provide sine or square or triangular waveforms. In the case of sine wave outputs, the phase difference between two sine waves is continuously adjustable over 0–180 degree. For the square and triangular waveforms, the time delay between two successive similar zero crossings of the two outputs is adjustable over the range of 0-T/2, where T is the time period of the waveform. In either case the phase difference or the time delay set is independent of the frequency of operation of the function generator.