Resistive Solid State Protective Device

Abstract: This thesis describes and explains different fault to characterize fault specifically for DC distribution systems and DC Microgrids fed by synchronous generators. This will result in a testbed for static and intermittent line-to-line faults, and in future work, various types of ground faults. Automaton allows for repeated testing at various voltage levels and precise control over intermittent fault generation. The fault generator is implemented with an IGBT H-bridge topology. Its physical implementation and benefits are described. Experimental results are shown for static line-to-line fault. This testbed will be used to help develop closed-form expressions. Once fault currents are characterized and closed-form expressions are made, adequate protection systems can be designed. finally, this paper will include the simulation and experimental results of line-to-line fault characterization with a DC smoothing capacitor, and intermittent faults of various times

POWER QUALITY CONTROL AND COMMON-MODE NOISE MITIGATION FOR INVERTERS IN ELECTRIC VEHICLES

Inverters are widely utilized in electric vehicle (EV) applications as a major voltage/current source for onboard battery chargers (OBC) and motor drive systems. The inverter performance is critical to the efficiency of EV system energy conversion and electronics system electro-magnetic interference (EMI) design. However, for AC systems, the bandwidth requirement is usually low compared with DC systems, and the control impact on the inverter differential-mode (DM) and common-mode (CM) performance are not well investigated. With the wide-band gap (WBG) device era, the switching capability of power electronics devices drastically improved. The DM/CM impact that was brought by the WBG device-based inverter becomes more serious and has not been completely understood. This thesis provides an in-depth analysis of on-board inverter control strategies and the corresponding DM/CM impact on the EV system. The OBC inverter control under vehicle-to-load (V2L) mode will be documented first. A virtual resistance damping method minimizes the nonlinear load harmonics, and a neutral balancing method regulates the unbalanced load impact through the fourth leg. In the motor drive system, a generalized CM voltage analytical model and a current ripple prediction model are built for understanding the system CM and DM stress with respect to different modulation methods, covering both 2-level and 3-level topologies. A novel CM EMI damping modulation scheme is proposed for 6-phase inverter applications. The performance comparison between the proposed methods and the conventional solution is carried out. Each topic is supported by the corresponding hardware platform and experimental validation

Resonant Behaviour of Pulse Generators for the Efficient Drive of Optical Radiation Sources Based on Dielectric Barrier Discharges

Dielectric barrier discharge (DBD) excimer lamps emit vacuum-UV optical radiation. This work presents novel methods for efficiently operating DBDs with short, high-voltage pulses. Transformer-less systems utilising SiC power semiconductor switches are presented. Pulse frequencies of up to 3.1 MHz and peak inverter efficiencies of 92 % were achieved. The work encloses both mathematical backgrounds of pulsed resonant circuits and practical implementation of low-inductive power stages

Design of LLC resonant converter with silicon carbide MOSFET switches and nonlinear adaptive sliding controller for brushless DC motor system

Introduction. The high voltage gain DC-DC converters are increasingly used in many power electronics application systems, due to their benefits of increased voltage output, reduced noise contents, uninterrupted power supply, and ensured system reliability. Most of the existing works are highly concentrated on developing the high voltage DC-DC converter and controller topologies for goal improving the steady state response of brushless DC motor driving system and also obtain the regulated voltage with increased power density and reduced harmonics, the LLC resonant DC-DC converter is implemented with the silicon carbide MOSFET switching devices Problem. Yet, it facing the major problems of increased switching loss, conduction loss, error outputs, time consumption, and reduced efficiency. Also the existing works are mainly concentrating on improving the voltage gain, regulation, and operating performance of the power system with reduced loss of factors by using the different types of converters and controlling techniques. The goal of this work is to obtain the improved voltage gain output with reduced loss factors and harmonic distortions. Method. Because, this type of converter has the ability to generate the high gain DC output voltage fed to the brushless DC motor with reduced harmonics and loss factors. Also, the nonlinear adaptive sliding controller is implemented to generate the controlling pulses for triggering the switching components properly. For this operation, the best gain parameters are selected based on the duty cycle, feedback DC voltage and current, and gain of silicon carbide MOSFET. By using this, the controlling signals are generated and given to the converter, which helps to control the brushless DC motor with steady state error. Practical value. The simulation results of the proposed LLC silicon carbide MOSFET incorporated with nonlinear adaptive sliding controller controlling scheme are validated and compared by using various evaluation indicators. Вступ. Високовольтні перетворювачі постійного струму з високим коефіцієнтом посилення напруги все частіше використовуються в багатьох прикладних системах силової електроніки через їх переваги, пов'язані з підвищеною вихідною напругою, зниженим рівнем шуму, безперебійним живленням і гарантованою надійністю системи. Більшість існуючих робіт значною мірою зосереджені на розробці топологій високовольтного перетворювача постійного струму і контролера з метою поліпшення усталеного відгуку системи приводу безщіткового двигуна постійного струму, а також отримання регульованої напруги з підвищеною щільністю потужності і зменшеними гармоніками; резонансний LLC-перетворювач постійного струму, реалізований на перемикаючих пристроях на основі польових МОП-транзисторах з карбіду кремнію. Проблема. Тим не менш, це стикається з основними проблемами, пов'язаними зі збільшенням втрат при перемиканні, втратами провідності, помилками на виході, витратами часу та зниженням ефективності. Крім того, існуючі роботи в основному зосереджені на покращенні коефіцієнта посилення напруги, регулювання та робочих характеристик енергосистеми із зменшенням факторів втрат за рахунок використання різних типів перетворювачів та методів управління. Метою роботи є отримання покращеного коефіцієнта посилення напруги зі зниженими коефіцієнтами втрат і гармонійних спотворень. Метод. Таким чином, цей тип перетворювача здатний генерувати вихідну постійну напругу з високим коефіцієнтом посилення, що подається на безщітковий двигун постійного струму, зі зменшеними коефіцієнтами гармонік та втрат. Крім того, реалізований нелінійний адаптивний ковзний регулятор для генерування керуючих імпульсів для належного спрацьовування перемикаючих компонентів. Для цієї операції вибираються найкращі параметри посилення на основі робочого циклу, постійної напруги та струму зворотного зв'язку, а також коефіцієнта посилення польового МОП-транзистора з карбіду кремнію. При цьому керуючі сигнали генеруються і передаються на перетворювач, який допомагає керувати безщітковим двигуном постійного струму з помилкою, що встановилася. Практична цінність. Результати моделювання запропонованого LLC-перетворювача на основі польових МОП-транзисторів з карбіду кремнію зі схемою управління нелінійним адаптивним ковзним регулятором перевіряються та порівнюються з використанням різних показників оцінки.&nbsp

Small Form Factor Hybrid CMOS/GaN Buck Converters for 10W Point of Load Applications

abstract: Point of Load (PoL) converters are important components to the power distribution system in computer power supplies as well as automotive, space, nuclear, and medical electronics. These converters often require high output current capability, low form factor, and high conversion ratios (step-down) without sacrificing converter efficiency. This work presents hybrid silicon/gallium nitride (CMOS/GaN) power converter architectures as a solution for high-current, small form-factor PoL converters. The presented topologies use discrete GaN power devices and CMOS integrated drivers and controller loop. The presented power converters operate in the tens of MHz range to reduce the form factor by reducing the size of the off-chip passive inductor and capacitor. Higher conversion ratio is achieved through a fast control loop and the use of GaN power devices that exhibit low parasitic gate capacitance and minimize pulse swallowing. This work compares three discrete buck power converter architectures: single-stage, multi-phase with 2 phases, and stacked-interleaved, using components-off-the-shelf (COTS). Each of the implemented power converters achieves over 80% peak efficiency with switching speeds up-to 10MHz for high conversion ratio from 24V input to 5V output and maximum load current of 10A. The performance of the three architectures is compared in open loop and closed loop configurations with respect to efficiency, output voltage ripple, and power stage form factor. Additionally, this work presents an integrated CMOS gate driver solution in CMOS 0.35um technology. The CMOS integrated circuit (IC) includes the gate driver and the closed loop controller for directly driving a single-stage GaN architecture. The designed IC efficiently drives the GaN devices up to 20MHz switching speeds. The presented controller technique uses voltage mode control with an innovative cascode driver architecture to allow a 3.3V CMOS devices to effectively drive GaN devices that require 5V gate signal swing. Furthermore, the designed power converter is expected to operate under 400MRad of total dose, thus enabling its use in high-radiation environments for the large hadron collider at CERN and nuclear facilities.Dissertation/ThesisMasters Thesis Electrical Engineering 201

Power Semiconductors for An Energy-Wise Society

This IEC White Paper establishes the critical role that power semiconductors play in transitioning to an energy wise society. It takes an in-depth look at expected trends and opportunities, as well as the challenges surrounding the power semiconductors industry. Among the significant challenges mentioned is the need for change in industry practices when transitioning from linear to circular economies and the shortage of skilled personnel required for power semiconductor development. The white paper also stresses the need for strategic actions at the policy-making level to address these concerns and calls for stronger government commitment, policies and funding to advance power semiconductor technologies and integration. It further highlights the pivotal role of standards in removing technical risks, increasing product quality and enabling faster market acceptance. Besides noting benefits of existing standards in accelerating market growth, the paper also identifies the current standardization gaps. The white paper emphasizes the importance of ensuring a robust supply chain for power semiconductors to prevent supply-chain disruptions like those seen during the COVID-19 pandemic, which can have widespread economic impacts.The white paper highlights the importance of inspiring young professionals to take an interest in power semiconductors and power electronics, highlighting the potential to make a positive impact on the world through these technologies.The white paper concludes with recommendations for policymakers, regulators, industry and other IEC stakeholders for collaborative structures and accelerating the development and adoption of standards