Sinusoidal Output Research Articles

Study, analysis, and development of a small‐scale AC‐AC modular multilevel converter for solid‐state transformer applications

SummaryThe modular multilevel converter presents itself as a promising topology in medium voltage and high power applications due to its modular characteristic and flexibility in applications where DC‐AC and AC‐DC power conversion are required. Despite this, applications with electric traction present this topology in the AC‐AC conversion due to the converter at the input of a solid‐state transformer and the power system's single‐phase characteristic at the converter's input. One of the main problems characteristic of this topology is the harmonic content present in the medium frequency converter output voltage due to its square waveform. Thus, the harmonic content in this voltage is high, increasing the losses and volume in the core of the medium frequency transformer. This paper presents a multilevel modulation scheme using two frequency components in the modulating wave to reduce the harmonic content in the medium frequency converter output voltage. With the converter branch inductors, it is possible to verify the filtering of the output voltage and thus reduce the harmonic content of this voltage. A low power and voltage (1 kW/500 V) of the AC‐AC modular multilevel converter is implemented, and simulation results show some operating characteristics of the modulation scheme. Experimental results at low power and voltage (0.6 kW/208 V–125 V/1.2 kHz) present the operation of the converter and the characteristics proposed by the modulation scheme, where it is possible to verify the waveform of the sinusoidal output voltage with lower harmonic content.

Design and torque calculation of permanent magnet eddy current coupling with sinusoidal torque output

Design and torque calculation of permanent magnet eddy current coupling with sinusoidal torque output

Mixed-mode Multiphase Sinusoidal Oscillators using Differential Voltage Current Conveyor Transconductance Amplifiers and Only Grounded Passives Components

This article is about mixed-mode multiphase sinusoidal oscillators that are made up of differential voltage current conveyor transconductance amplifier (DVCCTA) and use all the grounded passive components. The proposed multiphase sinusoidal oscillators provide a single DVCCTA, a single grounded resistor and a capacitor for each phase which is suitable for integrated circuit implementation. In addition, the sinusoidal outputs generate currents and voltages simultaneously. The current signals from the outputs have high impedances, which make it easier to connect them directly to the next circuit or stage. The proposed circuits can generate multiphase sinusoidal signals that are both equally phased and in amplitude. The oscillation can be adjusted simultaneously of the frequency of oscillation by the electronic method. A simulation with the PSPICE program and an experiment with commercially available ICs (AD830, AD844, and LM13700N) demonstrated. The results show the efficiency of the circuit is completely consistent with the theory.

Comparative Study of Conducted Common-Mode EMI in WBG-Enabled DC-Fed Three-Phase Current-Source Inverter

In pulsewidth-modulated (PWM) inverters, common-mode (CM) voltage and associated conducted CM electromagnetic interference (EMI) can cause motor bearing failures, ground leakage current, and audio susceptibility issues. When wide bandgap (WBG) devices are used to construct a voltage-source inverter (VSI), the CM EMI issues become more challenging. The current-source inverter (CSI) is an alternative, which produces more sinusoidal output voltage waveforms, making it a promising topology for reducing CM EMI in power converters. However, there is little systematic and comprehensive analysis of CSI’s CM EMI, especially when using WBG devices. The conducted CM EMI generation mechanisms of dc-fed two-level VSIs and CSIs are compared in this article. The analytical derivation and the circuit analysis are performed to identify the CM EMI generation mechanisms in both inverters, including CM voltage sources and the resulting CM current flowing paths. The effects of WBG devices on the CM EMI of both inverters are discussed. New CM EMI equivalent circuits (EQCs) of both inverters are analytically derived to reduce the computational time of full-circuit CM EMI simulation. Different filtering schemes and inverter topology variations’ impacts on CSI’s CM EMI are evaluated using the derived EQC. An effective CM EMI filter is designed to suppress the CSI’s CM EMI to be lower than EMI standards.

Research on Sliding Mode Observer of MMC Capacitor Voltage

In the practical application of modular multilevel converters (MMC), with the improvement of voltage level and power, more submodules (SMs) need to be cascaded in order to obtain more levels with different amplitudes to approximate the sinusoidal output voltage. The acquisition of submodule capacitor voltage is the premise of MMC capacitor voltage control, which makes the MMC system need many sensors to monitor sub-module capacitor voltage. In order to reduce the number of sensors and weaken the system jitter, this paper collects the current signal of the MMC bridge arm combined with the switching signal of the submodule and uses the saturation function set as the switching function of the sliding mode observer (SMO) to estimate the capacitor voltage. The simulation results show that the sliding mode observer has good robustness and accuracy.

Development of an Enhanced Selective Harmonic Elimination for a Single-Phase Multilevel Inverter with Staircase Modulation

A low device switching frequency is recommended for the operation of multilevel inverters (MLIs) to achieve reduced switching losses. Selective harmonic elimination (SHE) and total harmonic distortion (THD) minimization are the two primary switching angle estimation methodologies for low-frequency modulation control. In this regard, a new generalized condition has been developed in this paper for the SHE technique. This original condition will give an output voltage with improved THD in comparison to the conventional SHE technique, while achieving its primary objective of eliminating the specific harmonic content from the output voltage. The proposed condition has been formulated by estimating the error associated with the staircase waveform and the desired sinusoidal output at the fundamental frequency. An infinite harmonic count has been considered for the evaluation of the quality of output, to obtain an accurate THD value without any underestimation. The proposed technique is analyzed, and its critical features are studied in Simulink. The effectiveness of the present work has been also validated by the experimental results.

Design Voltage Controller of Bipolar SPWM Voltage Source Inverter

This paper presents single phased VSI (Voltage Source Inverter) type bipolar SPWM. The main purpose of this system is generating a constant sinusoidal output waveform without affected by load (resistive) demand. Its concept is to get reference voltage from PI control and compare it with modulated triangular carrier for controlling inverter’s switches. The system is also represented by a LCL output filter. The LCL filter is employed to reduce the high frequency harmonic components in current waveform due to PWM switching and to reduce the output current THD. Simulation result and analysis are bravely presented to verify the effectiveness of proposed approach.

The LLCLC resonant converter based pseudo DC link inverter

Technological advancements in solar power systems necessitate highly reliable power inverters with high efficiency and small size. An LLC resonant converter-based pseudo-Direct Current (DC) link inverters offer these qualities to some extent. The resonant circuits of conventional pseudo-DC link inverters cannot attain a zero gain and cannot handle variable frequency control which in turn requires very large filters to produce pure sinusoidal output voltages for the grid. The usage of these filters consequences in the enhanced price and size of inverters; moreover, the reliability of inverters is also reduced. We propose a novel topology for a pseudo-DC link inverter based on an LLCLC resonant converter. The proposed inverter does not require large filters, because it generates rectified sinusoidal output voltages. An additional parallel LC component is added in series to the resonant circuit, which makes it able to attain a zero gain through an infinite circuit impedance. The 400 W pseudo-DC link inverter with a 40 V input and a 400 V output is designed and simulated on OrCAD PSpice software. The results showed that there is a significant improvement in achieving a zero gain. The possible lowest gain achieved is approximately 0.125. The proposed technique claimed to be more efficient than those formerly used, subsequently contributing to satisfying outcomes.

Performance investigation of modular multilevel inverter topologies for photovoltaic applications with minimal switches

Introduction. In recent years, a growing variety of technical applications have necessitated the employment of more powerful equipment. Power electronics and megawatt power levels are required in far too many medium voltage motor drives and utility applications. It is challenging to incorporate a medium voltage grid with only one power semiconductor that has been extensively modified. As a result, in high power and medium voltage settings, multiple power converter structure has been offered as a solution. A multilevel converter has high power ratings while also allowing for the utilization of renewable energy sources. Renewable energy sources such as photovoltaic, wind, and fuel cells may be readily connected to a multilevel inverter topology for enhanced outcomes. The novelty of the proposed work consists of a novel modular inverter structure for solar applications that uses fewer switches. Purpose. The proposed architecture is to decrease the number of switches and Total Harmonic Distortions. There is no need for passive filters, and the proposed design enhances power quality by creating distortion-free sinusoidal output voltage as the level count grows while also lowering power losses. Methods. The proposed topology is implemented with MATLAB / Simulink, using gating pulses and various pulse width modulation methodologies. Moreover, the proposed model also has been validated and compared to the hardware system. Results. Total harmonic distortion, number of power switches, output voltage and number of DC sources are compared with conventional topologies. Practical value. The proposed topology has been very supportive for implementing photovoltaic based multilevel inverter, which is connected to large demand in grid.

Electronically Adjustable Multiphase Sinusoidal Oscillator with High-Output Impedance at Output Current Nodes Using VDCCs

This paper presents the high-output-impedance current-mode multiphase sinusoidal oscillators (MSO) using voltage differencing current conveyor (VDCC)-based lossy integrators, which consist of one VDCC, one grounded capacitor, and two grounded resistors. The proposed oscillator can provide an odd-phase and even-phase system without the use of an additional amplifier. The frequency of oscillation (FO) is electronically tuned via the bias current without affecting the condition of oscillation (CO). The proposed oscillator is designed to obtain three-phase sinusoidal waveforms (n = 3). The effect of non-idealities of VDCC on the lossy integrator section is also investigated. The validity of the proposed circuit is demonstrated by PSPICE simulation using 0.18 µm TSMC CMOS process parameters with ±0.9V power supply. The frequency of oscillation obtained from the simulation is 1.43 MHz. The total harmonic distortions of the sinusoidal output currents IO1, IO2, and IO2 are 1.22%, 1.18%, and 0.57%. The IO1–IO2 and IO2–IO3 phase differences are approximately 121 and 119 degrees, respectively. The feasibility of the proposed MSO is also verified with experimental results using the VDCC constructed from the commercially available ICs (LT1288 and AD844) with ±5 V power supply. The results of PSPICE simulations and experiments are closely consistent with the theoretical expectation.

RANCANG BANGUN CONTROLLER BLDC BERBASIS MIKROKONTROLER STM32 BLUE PILL PADA KENDARAAN LISTRIK URBAN AGNIJAYA WEIMANA

The increase in the consumption of fuel oil causes the depletion of fossil fuel reserves. One alternative energy solution that can be utilized is electrical energy. One of the efforts to overcome the energy crisis can be realized in a creativity in the energy efficient car contest (KMHE). The Weimana Team of Udayana University participated in the urban concept category of electric motor drive under the name Agnijaya Vehicle. One important aspect in order to be able to compete and win the competition is the Motor Controller. In this paper, the results of the research are presented on a design of a Brushless DC Motor Controller based on the STM32 Blue Pill microcontroller and used to rotate the BLDC motor on the Agnijaya Weimana Urban Electric Vehicle. The specifications of the BLDC controller design are made to have a power dissipation inverter with a power of 1980 Watt connected to an 800 Watt sensored BLDC motor. The STM32 Blue Pill microcontroller-based Brushless DC Motor Controller has been successfully designed and manufactured and produces a sinusoidal output waveform containing switching noise when connected to a no-load BLDC motor. The performance to drive Agnijaya Wimana's Urban Electric Vehicle is capable of implementing a PWM duty cycle of up to 100% with an average current achievement of 24,775 Ampere, an average voltage drop of up to 48,485 VDC, an average power rating of up to 1200,5 Watt and a BLDC motor speed up to 419,5 RPM.

A High-Gain and High-Efficiency Photovoltaic Grid-Connected Inverter with Magnetic Coupling.

Conventional photovoltaic (PV) grid-connected systems consist of a boost converter cascaded with an inverter, resulting in poor efficiency due to performing energy processing twice. Many pseudo DC-link inverters with single energy processing have been proposed to improve system efficiency and simplify circuits. However, their output voltage gain is limited by the non-ideal characteristics of the power diode, making them difficult to apply in high-output voltage applications. This paper proposes combining a boost converter with magnetic coupling and a full-bridge unfolding circuit to develop an inverter featuring high voltage-gain and high efficiency. According to the desired instantaneous output voltage, the high-gain boost converter and the full-bridge unfolding circuit are sequentially and respectively controlled by SPWM. A sinusoidal output voltage can be generated by performing energy processing only once, effectively improving the conversion efficiency. Magnetic coupling is adopted to increase the voltage gain of step-up, and the step-down function is realized by the full-bridge unfolding circuit to reduce conduction loss. Finally, a 500 W prototype was fabricated for the proposed high-gain inverter. The experimental results were used to verify the correctness of the theoretical analysis and the feasibility of the circuit structure.

Reduction of harmonics emission of a WECS in the electrical grid using multilevel inverters

<span lang="EN-US">Wind energy conversion system (WECS) is composed of many non-linear power electronic sub systems, which contribute significantly in harmonic emissions that is a threat for the quality of electrical power. Hence, for a better integration of WECS in the electrical grid and in order to satisfy IEEE 519 standards, WECS must inject a quality power with a rate of total harmonics distortion (THD) that is less than 5%. Multilevel Inverters are an emerging solution for having a perfect sinusoidal output voltage with minimum harmonic content and lower switching losses than the two-level inverter so that only a smaller filter size is required. Thus, in this paper we are presenting a significantly improved results of the reduction of the grid injected current THD using three types of inverters (two-levels, three-levels NPC, and five-levels H-bridge cascade) for a WECS and comparing the THD performances of using each of the studied inverter. All results of THD are verified by a Fast Fourier transform simulation using MATLAB/Simulink. </span>

Three Phase Grid Connected Inverter for Solar Photovoltaic Systems

Abstract: The main aim is to convert the Solar PV DC voltage into AC voltage by using 3 phase inverter and getting sinusoidal AC output voltage. To convert solar PV which is in DC needs to be converted into AC by using the devices like 3 phase inverter and boost converter. The solar PV is a variable DC that is to be converted into pure DC for which will convert variable DC to pure DC. The MPPT is designed and is applied to boost converter which increases the solar PV’s efficiency. Then the output of boost converter which is DC voltage is given to 3 phase inverter. The 3 phase inverter which is connected to output of boost converter will convert the DC voltage into AC and we get sinusoidal AC. A three-phase grid-connected inverter designed for a photovoltaic power plant that features a maximum power point tracking (MPPT) scheme based on fuzzy logic. The whole system simulate in MATLAB. This fuzzy MPPT will shows accurate and fast response, and is integrated in the inverter.

A Novel Non-Isolated Step-Up DC/AC Inverter with Less Switches

In order to solve the problem of leakage current and step-up voltage capability associated with the single-phase single-stage non-isolated inverter, a new topology is proposed in this paper. The proposal has the advantages of less switch components, high step-up voltage capability and no leakage current. The three operation modes are discussed and the modulation strategy is designed. Finally, the prototype of the proposed new single-phase single-stage non-isolated inverter is established. The TMS320F28335 DSP and Xilinx XC6SLX9 FPGA are used to provide the system with digital control. The experimental results show that the proposed inverter achieved the boosted ability as well as the sinusoidal output voltage, whose total harmonic distortion is well below 5%, which meets the IEEE Std. 519-2014.

Implementasi Inverter Berbasis Square Wave dan Sinusoidal PWM Menggunakan Arduino Uno

Inverters with square waves and sinusoidal output signal waves have different efficiency values. The difference is very visible, especially when the inverter is used to drive an electric device that uses a motor. In a sinusoidal wave type inverter, electricity consumption will be more efficient than the use of a square wave type inverter. This study aims to determine the efficiency value of the square wave and sinusoidal inverter wave output in supplying the load. Square wave and sinusoidal inverters require a controller, the controller uses an Arduino Uno which acts as an SPWM signal generator and a square wave signal is used to drive the MOSFET with push-pulls topology. Based on the results of the inverter test to determine the efficiency, it shows that the inverter with sinusoidal output is 96.40% better, while the inverter with square wave output is only 83.34%, this test is carried out using a 50W LED lamp load .

Standalone PV-based single-phase split-source inverter using model-predictive control

This paper proposes the control of single-phase split-source inverter (SSI) for a standalone PV application using model-predictive control scheme. The PV system under investigation consists of PV modules, single-phase SSI, battery bank for energy storage, and DC-DC bidirectional converter to allow for bidirectional power flow with the batteries. Maximum power is extracted from the PV array using PI-based incremental conductance method. Both the maximum power point tracking of the PV modules and the synthesis of the sinusoidal output load voltage are achieved using the SSI. The control of the bidirectional converter is carried out using PI controllers to regulate the DC-link voltage. Selection of the controllers parameters is achieved using Harris Hawks optimization technique. Simulation results show that the system has succeeded in producing a constant DC-link voltage and well-regulated AC load voltage with low THD under various operating conditions. Experimental results verify the system performance.

Design a Simulation of Multilevel Inverter for Reduction of Harmonics for Grid Connected PV System

Abstract: The existing topologies, Multilevelinverters acts as a promising solution for medium voltage, high power applications due to their modularity and reduced voltage stress across the power switches. They are becoming popular due to reduced voltage stress of the power switches and low THD. Among the different multilevel configurations, H bridge multi-level inverter (HBMLI) is found to beattractive for grid connected PV applications. H Bridge Multilevel Inverters (HB-MLI) are being considered as the best choice for grid connected Photovoltaic (PV) systems since they require several sources on the DC side. By means of high-quality output with less harmonic distortion is obtained compared to a two-level inverter. Different levels of output viz. three level is examined and conclusions are drawn mainly based on the number of switches andTotal Harmonic Distortion (THD). The main advantages of the multilevel inverter are that the regulation of the DC buses is simple. More number of levels results in reduced THD and nearly sinusoidal output. Simulation is performed using Matlab/Simulink.

Multiresonant-Frequency Filter for an Electrosurgery Inverter.

This paper presents a multi-resonant-frequency (MRF) filter for a high-frequency inverter (HFI) used in electrosurgery. The fundamental (sinusoidal) output frequency of the HFI is 390 kHz and is the same as the switching frequency of the HFI. The MRF is designed to extract the fundamental frequency of the tri-state bipolar waveform, generated by the HFI operating with phase-shift control. The structure and operation of the MRF are outlined. An experimental 300 W GaN-FET-based HFI prototype is developed to validate the feasibility of the proposed MRF under closed-loop control.

Energy Function Based Finite Control Set Predictive Control Strategy for Single-Phase Split Source Inverters

This article presents energy-function based model predictive control (EF-MPC) for single-phase split source inverters. Unlike conventional MPC methods, the proposed EF-MPC is designed by considering the stability of inverter. According to the Lyapunov's direct method, the stability of inverter can be assured if the derivative of energy-function is always negative. Motivated from this fact, the design of cost function in EF-MPC is based on the energy function which involves dc- and ac-side inductor current errors. It is shown that the coefficient used in the formulation of energy function is redundant which eliminates the weighting factor required in the multiobjective cost function. Elimination of the weighting factor not only simplifies the controller design in the practical implementation, but also removes the weighting factor tuning process needed in the conventional predictive methods. Another advantage of the proposed EF-MPC is that the amplitude of low-frequency component in the dc-side inductor current is suppressed. The steady-state and dynamic performances of the proposed EF-MPC are investigated experimentally under linear and nonlinear loads. In both cases, the dc-side variables are regulated at the desired values while the sinusoidal output voltage with low total harmonic distortion is obtained in the ac-side.