Modulation Inverter Research Articles

A Power Boosting Method for Wireless Power Transfer Systems Based on a Multilevel Inverter and Dual-Resonant Network

With the deepening of research on wireless power transfer (WPT) technology, there is an urgent need to improve the output power of WPT systems. Therefore, this paper proposes a power boosting method based on a multilevel inverter and dual-resonant network. The system adopts a five-level inverter whose output voltage contains rich fundamental and harmonic components. The transmitting side adopts a dual-resonant compensation network, and, through its parameter configuration, the system can be in a resonant state at both the fundamental and third harmonic frequencies. The receiving side adopts two receiving channels which can simultaneously receive power at both frequencies, thus boosting the output power. Firstly, the overall structure and operating principle of the system are introduced. Then, the relationship between the system output power and efficiency with the inverter modulation parameters is obtained and the strategy for selecting the optimal operating points of the inverter is designed by comprehensively considering the THD of the inverter output voltage and the efficiency of the system. Furthermore, the proposed system is simulated in a Matlab/Simulink platform. Finally, an experimental setup is created to verify the proposed method. The results show that, compared with the single-channel WPT system, the proposed method can enhance the output power from 160 W to 310 W with a boosting coefficient of nearly double and with the highest efficiency exceeding 92%.

Polymer Coating Enabled Carrier Modulation for Single-Walled Carbon Nanotube Network Inverters and Antiambipolar Transistors.

The control of the performance of single-walled carbon nanotube (SWCNT) random network-based transistors is of critical importance for their applications in electronic devices, such as complementary metal oxide semiconducting (CMOS)-based logics. In ambient conditions, SWCNTs are heavily p-doped by the H2O/O2 redox couple, and most doping processes have to counteract this effect, which usually leads to broadened hysteresis and poor stability. In this work, we coated an SWCNT network with various common polymers and compared their thin-film transistors' (TFTs') performance in a nitrogen-filled glove box. It was found that all polymer coatings will decrease the hysteresis of these transistors due to the partial removal of charge trapping sites and also provide the stable control of the doping level of the SWCNT network. Counter-intuitively, polymers with electron-withdrawing functional groups lead to a dramatically enhanced n-branch in their transfer curve. Specifically, SWCNT TFTs with poly (vinylidene fluoride) coating show an n-type mobility up to 61 cm2/Vs, with a decent on/off ratio and small hysteresis. The inverters constructed by connecting two ambipolar TFTs demonstrate high gain but with certain voltage loss. P-type or n-type doping from polymer coating layers could suppress unnecessary n- or p-branches, shift the threshold voltage and optimize the performance of these inverters to realize rail-to-rail switching. Similar devices also demonstrate interesting antiambipolar performance with tunable on and off voltage when tested in a different configuration.

A new gate driver employing linearly sweep signal generated module for high‐resolution micro‐LED display with line‐by‐line pulse width modulation driving method

AbstractA new gate driver with metal oxide thin‐film transistors (MO‐TFTs) has been presented for micro‐light‐emitting diode (Micro‐LED) display. The proposed gate driver employing linearly decreasing sweep signal generated module could realize the line‐by‐line pulse width modulation (PWM) driving method, which is valuable for application in high‐resolution Micro‐LED display compared with the conventional driving method employing global sweep signal. A simple Micro‐LED pixel circuit including an inverter module driven by the analog PWM method is employed to demonstrate the feasibility of the proposed gate driver. A 10 × 10 green Micro‐LED display array has been fabricated with MO‐TFTs backplane technology. It is shown that a 10‐μs width pulse and linearly scanning sweep signal can be successfully output. Consequently, the pixel circuit array can be driven properly under analog line‐by‐line PWM driving method.

Design of small independent photovoltaic power generation system

Abstract This article designs a small independent photovoltaic power generation system, which includes solar panels, controllers, batteries, and inverter modules. The design requirements and principles of boost converters and inverters were elaborated, and the inverters were simulated in Matlab; The fuzzy control method was selected to track the maximum power point, and its effectiveness was verified through MATLAB simulation; Corresponding methods have been proposed to prevent or reduce factors that affect the output power of photovoltaic arrays, such as power attenuation, shielding loss, and temperature rise loss. It has extremely important significance for promoting the development of photovoltaic power generation, achieving zero carbon goals, and sustainable development of human society.

Highly sensitive protection scheme considering the PV operation control models

The integration of distributed generation (DG) based on inverters into power systems has increased significantly, necessitating a thorough understanding of its impact on fault analysis and the performance of distribution networks' protection mechanisms. This study addresses this issue by examining how various inverter management modes influence protective relay systems within IEEE 9-bus redial and mesh networks, CIGRE and IEEE 33-bus networks featuring Photovoltaic (PV) farms and Battery Energy Storage Systems (BESS), by IEEE1547–2018 and German grid code standards. By analyzing grid-connected scenarios with five distinct PV control modes, the research introduces a novel protection methodology termed the Photovoltaic Overcurrent Relay (PVOCR). This method introduces a current-voltage characteristic to optimally coordinate Overcurrent Relays (OCRs), aiming to reduce their operational time and eliminate mis-coordination events. The proposed PVOCR is evaluated against standard inverse time, SOCR, and modern adaptive voltage, VOCR, relay schemes across various fault scenarios differing in type and location. Furthermore, the PVOCR scheme effectively operates across all PV inverter modes without experiencing miscoordination events, whereas the SOCR and VOCR schemes encountered such issues during the operation of Control 4. These results underscore the potential utility of the PVOCR methodology in enhancing the reliability and efficiency of protection systems in inverter-based DG networks.

Digital Functional Blocks Implementation of PWM and Control for a High-Frequency Interleaved Y-Inverter Motor Drive

This paper is about the development and demonstration of a motor drive for e-transport applications based on an innovative hybrid Si-SiC dual switching frequency interleaved buck–boost Y-inverter and a single-rotor Halbach machine. In particular, the focus is the implementation of the required discontinuous inverter modulation scheme, input voltage feed-forward and motor currents feedback control loops, as well as over-voltage, over-current, and over-temperature protections, using an off-the-shelf commercial hardware platform enabling straightforward Simulink-environment programming of all parts, while ensuring the high switching frequency capability required by wide-band-gap semiconductors. Experimental results showed good inverter efficiency, transient dynamic response to load changes, input voltage regulation, and fully functional protection capability, validating the proposed approach as a powerful option for reducing system development time and cost.

Harmonic Self-Compensation Control for Bidirectional Grid Tied Inverter Based on Crown Porcupine Optimization Algorithm

A self-compensating control strategy for harmonic parameters based on the crown porcupine optimization algorithm is proposed for the single-phase rectifier and two-phase inverter operation mode of the bidirectional converter. In order to improve the response speed of the inverter voltage, the instantaneous expressions of the phase angle coefficient and amplitude coefficient of the dc-side voltage doubling fluctuation are derived, and the third harmonic is calculated based on the crown porcupine optimization algorithm according to the Proportional Integral (PI) + Quasi-Proportional Resonance (QPR) double closed-loop control method and injected into the input voltage of the inverter side to offset the influence of the bus-doubling fluctuation on the output voltage of the two-phase inverters of B and C so that the total harmonic content of the two-phase output voltages of the two-phase inverters of B and C can be reduced. The total harmonic content of the B and C inverter output voltages is reduced. The effective control of the control method for single-phase rectifier two-phase inverter mode is verified through simulation. Finally, the effectiveness of the control strategy is verified by experimenting with a 15 kW LCL-type bi-directional converter prototype.

Wireless charging system design based on ICPT topology

Abstract Aiming at the situation that the wired charger for inspection equipment has electrodes that are prone to rust and corrosion, poor contact, and inspection equipment cannot enter and exit the charging dock normally, this paper designs a set of non-contact charging systems. The system consists of two parts, the transmitter board, and the receiver board, mainly including power factor correction, high-frequency inverter, resonant circuit, charging control, circuit protection, and other modules. The transmitter board first converts the utility power into 60 kHz AC power and then transmits it to the receiver board through the resonant network. The receiving board charges the battery through the charging control circuit. The test results show that the wireless charger works stably and reliably, has perfect protection functions, and has a maximum output power of 150 W, which can meet the charging needs of most inspection equipment.

Fuzzy sliding mode control with adaptive exponential reaching law for inverters in the photovoltaic microgrid

Photovoltaic inverters are widely utilized in microgrid systems working as the key equipment for converting solar energy into usable electricity. This paper presents a fuzzy sliding mode control (FSMC) method for the photovoltaic inverter in a microgrid. The inverter module uses voltage control to achieve stable AC output voltage. Moreover, to deal with system uncertainty and non-linearity in the photovoltaic inverter, a fuzzy controller was designed to realize real-time adaptation of the gains of the constant term and the reaching term in the sliding mode control law, which serves as a compensating controller for traditional sliding mode control. The gains of the exponential reaching law can be adjusted according to the system state instead of fixed gains, which can effectively reduce the chattering phenomenon and improve the robustness of the photovoltaic microgrid. Finally, the Lyapunov stability theory was used to ensure the stability of the entire control system, achieving a high-performance independent power supply for loads in a microgrid. Simulation results show that the designed control system is more robust to load disturbances and has superior dynamic performance.

An energy efficient control method of a photovoltaic system using a new three-phase inverter with a reduced common mode voltage

This paper presents a new energy-efficient space vector pulse width modulation (SVPWM) for controlling the switches of a New three-phase inverter (NTPI) for photovoltaic (PV) applications to reduce switching losses, the peak value, and the dv/dt of the common mode voltage (CMV) with fewer number of switches. The proposed system offers a reliable operation in PV energy system with less leakage current and increased efficiency because of the reduction of the CMV, the source of leakage current in PV inverter-based application. Moreover, this also optimizes the operation of electric vehicle application with lower bearing failure. The performance of the proposed system with the new SVPWM is evaluated to the existing PWM in the literature, as well as the active zero state pulse width modulation (AZSPWM) of the two-level inverter introduced under identical conditions. Experiments and MATLAB simulations have both been used in this study.

Investigation of bidirectional three-phase four-leg converter with LCL filter

A three-phase four-leg bidirectional power converter used as an input stage of an energy storage system using the inductance (L), capacitance (C), and inductance (L) or LCL filter on the grid side is considered. The article provides a variant of the three-phase four-leg bidirectional converter control system implementation based on 3D space vector pulse-width modulation and per-phase voltage control. A brief analysis of the applied control algorithms of the three-phase four-leg bidirectional converter in inverter and rectifier modes is given. A computer model has been built to investigate the operating modes of the converters of the designated class with both balanced and unbalanced load. Studies were carried out by computer modeling methods in order to optimize the parameters of the LCL filter on the grid side with bidirectional energy exchange. Optimal LCL filter parameters and modulation frequencies are determined for the developed converter, providing acceptable quality indicators when operating in bidirectional mode.

Loss Modeling and Testing of 800-V DC Bus IGBT and SiC Traction Inverter Modules

Loss Modeling and Testing of 800-V DC Bus IGBT and SiC Traction Inverter Modules

Comparison of three-phase inverter modulation techniques: a comprehensive analysis of SPWM and SVPWM

With the increasing utilization of renewable energy sources like solar and wind, three-phase inverters have become indispensable equipment for grid-connected energy systems, sparking significant research interest in the field of power electronics. This paper presents a comprehensive comparison of two primary modulation techniques employed in three-phase inverters: Sinusoidal Pulse Width Modulation (SPWM) control and Space Vector Pulse Width Modulation (SVPWM) control. The aim is to elucidate their respective advantages and disadvantages, particularly focusing on their performance under various control models. Through a systematic analysis of parameters such as total harmonic distortion under different control schemes including the unity power factor control model, the V/F control model, and the modulation ratio, this paper delves into the operational principles, strengths, and weaknesses of SPWM and SVPWM. Additionally, it elucidates the distinctions between these two modulation techniques and their interconnections. Lastly, the paper provides insights into the future development prospects and identifies potential technical challenges in the realm of pulse width modulation techniques.

Radiated Electromagnetic Emission from Photovoltaic Systems—Measurement Results: Inverters and Modules

Radiated electromagnetic emission of photovoltaic systems, for example, adversely impacting radiocommunication, can pose a major barrier against further increase in photovoltaic penetration. This is particularly the case near sensitive infrastructure and activities such as hospitals, airports, search and rescue, and military. To understand the impact of each component and installation detail, we performed systematic radiated electromagnetic emission measurements on comparable commercial photovoltaic systems in the frequency range 150 kHz to 30 MHz. Our measurements indicate that string inverters are unlikely to interfere with radiocommunication when installed according to recommended standards, rules, guidelines, and regulations. It was shown that module-level power optimizers are the main cause of high levels of radiated emissions. The frameless bifacial module showed higher levels of radiated emissions than the monofacial module with frame. Changes in cable management and earthing have less impact on radiated emissions than the choice of solar inverter concept and module type.

A three level NPC inverter fault detection and identification using voltage vector residual evaluation based on current path tracking method

This research describes open circuit detection and fault location for active 3-level NPC (neutral point clamped) inverter switches during normal and connected to the neutral point. This work introduces the current path tracking method to correlate the operating mode of NPC inverter and switch status in abnormal and normal conditions. Furthermore, a hierarchal diagnosis approach is introduced for open circuit faults using output Voltage Vector Residual Evaluation (VVRE). The node potential and conduction path can be derived from the model to indicate the NPC inverter circuit faults. Two steps are involved in the diagnosis. First, OC fault can be determined by analyzing the difference between the reference voltage and actual voltage vector resulting from the specified current path utilization ratio. Therefore, using a current path state reconstruction method, we can distinguish faulty transistors with similar properties. The simulated results demonstrate the robustness and efficiency of the proposed approach.

Multilevel Inverter with Enhanced THD Value used in Grid Connected Applications

In this work, the relationships among pulse width modulation (PWM), sinusoidal pulse width modulation (SPWM), and space-vector pulse width modulation (SVPWM) for three-phase inverters will be analyzed to better comprehend their differences. detailed comparison of the three modulation schemes under study’s Total Harmonic Distortion (THD). High-power applications are increasingly concentrating on converter technology. This growing importance may be attributed to its improved output waveforms over the 3- carrier-based sinusoidal pulse width modulation (SPWM). To control and modulate multi-level inverters, many techniques are employed. These methods are categorized based on how frequently they switch. The ripple current rating, capacitance value, and voltage balance in the DC bus capacitors are all impacted by the pulse width modulation techniques. It is crucial to select the modulation method based on the current control requirements, as this determines the output voltage waveform’s harmonic content. SVPWM is gradually becoming more and more popular in industries because of its improved dc bus utilization and ease of digital realization. This work examines PWM, Sinusoidal, and SVPWM feeding a load connected to RL. Three different methodologies’ performances are compared as these methods are investigated through simulation with MATLAB/SIMULINK software.

Synergetic optimization operation method for distribution network based on SOP and PV

The integration of distributed generation brings in new challenges for the operation of distribution networks, including out-of-limit voltage and power flow control. Soft open points (SOP) are new power electronic devices that can flexibly control active and reactive power flows. With the exception of active power output, photovoltaic (PV) devices can provide reactive power compensation through an inverter. Thus, a synergetic optimization operation method for SOP and PV in a distribution network is proposed. A synergetic optimization model was developed. The voltage deviation, network loss, and ratio of photovoltaic abandonment were selected as the objective functions. The PV model was improved by considering the three reactive power output modes of the PV inverter. Both the load fluctuation and loss of the SOP were considered. Three multi-objective optimization algorithms were used, and a compromise optimal solution was calculated. Case studies were conducted using an IEEE 33-node system. The simulation results indicated that the SOP and PVs complemented each other in terms of active power transmission and reactive power compensation. Synergetic optimization improves power control capability and flexibility, providing better power quality and PV consumption rate.

Gated recurrent unit-based data-driven model for predicting pot temperature in induction cooking systems

On an induction cooker, accurate pot temperature monitoring can cut down on energy use and prevent overheating. It can be challenging to create a mathematical model for predicting pot temperature, though, because of the different materials and sizes of the pots and the intricate electromagnetic coupling between the induction coil and the pot. To solve this problem, this paper offered a data-driven model that forecasts pot temperature by the inverter module's measured temperature. We used thermocouples in contact with the bottom surfaces of the pots and inverters to record time-series data on the temperatures of the devices to make accurate predictions. This information was gathered under a variety of circumstances, including various pot sizes and materials, various power and temperature settings, and various water levels. We used a gated recurrent unit-based autoencoder to reduce noise in the inverter temperature that was brought on by the cooling fan operation. The data-driven model was then trained using a variety of machine learning and deep learning techniques, including support vector machines, decision trees, linear regression, artificial neural networks, and gated recurrent units. Finally, we compared the predicted and measured pot temperatures to validate the data-driven models that had been learned. According to the statistical findings, there was a 3 °C or so median temperature difference between predicted and actual temperatures.

An Algorithm for a Space-Vector Pulse Width Modulation with a Hybrid Switching Sequence for a Three-Level Neutral Point Clamped Voltage Source Inverter

This paper proposes a new algorithm for a space-vector pulse width modulation (SVPWM) with a hybrid switching sequence (SS) designed to control a three-level (3L) neutral point clamped (NPC) voltage source inverter (VSI). Based on the advantages of five-stage and seven-stage SS, we designed a hybrid SS to improve four key parameters in the system: inverter output current quality, neutral point (NP) and common-mode (CM) voltage levels, and switching losses of power switches. The proposed algorithm flexibly regulates meeting the four criteria depending on the system operating conditions by changing the regulation coefficient. The paper obtained an approximate dependence to determine the optimal regulation coefficient for any values of the inverter modulation coefficient when operating jointly with an active-inductive load. The effectiveness of the proposed algorithm is confirmed by computer simulation in the MatLab+Simulink environment, as well as the results of experimental studies. The paper presents the experimental dependences of static state spaces, including the distortion coefficient of higher current harmonics at the inverter output, the maximum error of the NP voltage, the number of switching pairs of power switches, and the pulse duty factor of CM voltage, depending on the inverter modulation coefficient and the regulation coefficient of the hybrid SS. The results showed that in the algorithm for a SVPWM with a hybrid SS, the number of switchings of power switches is reduced by an average of 13.5 % while maintaining the NP voltage balance and the quality of the curve at the inverter output at an acceptable level, close to a seven-stage SS (the deviations do not exceed 0.5 % and 0.2 %, respectively). The average CM voltage coefficient decreased by no more than 4.5 %. The indicators improve the energy saving, the weight-size parameters, and the operational reliability of the 3L NPC VSI. The application area of the algorithm is much wider and includes the control of power switches of active front ends, grid converters for electricity storage systems, active power filters, and power conditioners. DOI: https://doi.org/10.52783/pst.237

Design and Implementation of a Linear Induction Launcher with a New Excitation System Utilizing Multi-Stage Inverters

Linear induction launchers (LILs) are a specific subtype of linear motors. However, LILs are air-core machines that consistently operate in a transient rather than a steady state. Moreover, their operating currents and voltages exceed those of traditional machines. The execution time of LILs often remains within a few milliseconds, and it is essential to manage extremely high-power levels quickly. The control methods for LILs differ from those used for regular machines due to the differences from conventional linear motors. In this respect, there are still challenges to be overcome in power systems designed for LILs in the literature. This study has developed a novel power energization system to address these challenges, particularly in terms of inadequate V/f control and the unnecessary energization of regions along the barrel where no projectile is present. It focuses on the system’s design using multi-stage H-bridge inverters to produce a sinusoidal current for section-by-section polyphase excitation. An FPGA-based electronics control system generates bipolar PWM fiber-optical signals for IGBT switches for scalar V/f control of the inverters. Distributed multi-inverters power each stage of the launcher’s barrel and are controlled by the FPGA to create the travelling electromagnetic wave package. Three-dimensional FEM analysis is used for observation of the trigger timing to ensure positive force along the barrel. By driving each inverter independently, the coils on the barrel are excited sequentially based on the position of the projectile. This study also explains the implementation of a laboratory-scale barrel prototype, a 40 mm aluminum projectile, its power electronics, and the control part of the multi-stage inverters. In this study, 3300 V–1200 A IGBTs and 8.8 mF–2000 V DC-Link capacitors were used in the H-bridge inverter modules. Experimental studies have been conducted on the launcher, and the results obtained, including achieving a velocity of 30 m/s, are consistent with the electromagnetic simulations. It has been observed that the launcher, powered by the proposed system, is approximately 57.14% more efficient compared to the version energized by a single inverter.