Advanced Control Design for Grid-Connected Photovoltaic System and Electric Drives by Kamran Zeb-Department of Electrical and Computer Engineering The Graduate School Pusan National University

 Advanced Control Design for Grid-Connected Photovoltaic System and Electric Drives

 By Kamran Zeb August 2020 Department of Electrical and Computer Engineering The Graduate School Pusan National University 

 Abstract 

The application of Photovoltaic (PV) in the distributed generation system is acquiring more consideration with the developments in power electronics technology and global environmental concerns. Solar PV is playing a key role in consuming the solar energy for the generation of electric power. The use of solar PV is growing exponentially due to its clean, pollution-free, abundant, and inexhaustible nature. In grid-connected PV systems, significant attention is required in the design and operation of the inverter to achieve high efficiency for diverse power structures. The requirements for the grid-connected inverter include; low total harmonic distortion of the currents injected into the grid, maximum power point tracking, high efficiency, and controlled power injected into the grid. The performance of the inverters connected to the grid depends mainly on the control scheme applied. In this thesis, the global status of the PV market, classification of the PV system, configurations of the grid-connected PV inverter, classification of various inverter types, and topologies are discussed, described and presented in a schematic manner. A concise summary of the control methods for single- and three-phase inverters has also been presented. Finally, the criteria for the selection of inverters and the future trends are comprehensively presented. In addition, Grid-Connected PVS required advance DC-link controllers to overcome second harmonic ripple and current controllers to feed-in high-quality current to the grid. This thesis successfully presents the design of a Fuzzy-Logic Based PI (F-PI) and Fuzzy-Logic based Sliding Mode Controller (F-SMC) for the DC-link voltage controller and Proportional Resonant (PR) with Resonant Harmonic Compensator (RHC) as a current controller for a Single-Phase Two-Stages Grid-connected Transformerless (STGT) PV Inverter. The current controller is designed with and without a feedforward PV power loop to improve dynamics and control. A Second Order General Integral (SOGI)-based Phase Lock Loop (PLL) is also designed that has a fast-dynamic response, fast-tracking accuracy, and harmonic immunity. A 3 kW STGT-PV system is used for simulation in Matlab/Simulink. A comparative assessment of designed controllers is carried out with a conventionally well-tuned PI controller. The designed controllers improve the steady-state and dynamic performance of the grid-connected PV system. In addition, the results, performance measure analysis, and harmonics contents authenticate the robustness, fastness, and effectiveness of the designed controllers, related to former works. In this thesis, Smart Grid Initiative of the U.S department of energy based Single Phase Voltage-Source Smart Inverter (SPV-SSI) 5 kVA is designed and analyzed in detail that has the combined capability of supplying power to local load, injecting power into grid, supplying power to the utility load up to rated capacity of the inverter, store energy in lead acid battery bank, the ability to control voltage at the Point of Common Coupling (PCC) during voltage sags/faults, and decision making capability on real time pricing information obtained from the utility grid through advance metering. This thesis also includes complete design of Smart Inverter in dq synchronous reference frame, bidirectional DC-DC Buck-Boost converter, IEEE standard 1547 based islanding and recloser, and STATCOM functionalities. Moreover, optimal and advance controllers i.e. F-PI and F-SMC are designed. The performance of F-PI and Fxvi SMC is superior, stable, and robust in comparison to that of conventionally tuned PI controllers both for voltage control loop (islanded mode) and current control loop (grid connected mode). The simulation results effectively validate the efficacy of the proposed controllers. This thesis also presents modeling and design of a digital PR with RHC to feed-in high quality current. The novelty is on designing the control in a different approach than the conventional methods. As a result, practical engineers find an easy, fast and accurate way to design the control strategy. The proposed system has the capability to inject both active and reactive power in an effective manner. Synchronous reference frame-based phase lock loop that works well under nonideal and distorted grids, is used for synchronization. The platform used for simulation and auto code generation is PSIM 9.1 while code composer studio 6.2.0 is used for debugging. The feasibility and effectiveness of the design controller is also validated using Typhoon (Hardware in Loop) HIL 402 device for real time testing on the DSP board TMS32F28335 from Texas Instruments. The designed controller is tested under various distortion, disturbance, and non-ideal condition. The simulation and HIL results authenticate the robustness, fastness, and efficacy of the designed controller. Recently, the Indirect Field Oriented Control (IFOC) scheme for Induction Motors (IM) has gained wide acceptance in high performance applications. The IFOC has remarkable characteristics of decoupling torque and flux along with an easy hardware implementation. However, the detuning limits the performance of drives due to uncertainties of parameters. Conventionally, the use of a PID controller has been very frequent in variable speed drive applications. However, it does not allow for the operation of an IM in a wide range of speeds. In order to tackle these problems, optimal, robust, and adaptive control algorithms are mostly in use. The work presented in this thesis is based on new optimal, robust, and adaptive control strategies, including an Adaptive PI controller, sliding mode control, Fuzzy Logic (FL) control based on Steepest Descent (SD), Levenberg-Marquardt (LM) algorithms, FL based on Newton Algorithm (NA), FL based on Gauss Newton Algorithm (GNA) and Hybrid Control (HC) or adaptive sliding mode controller to overcome the deficiency of conventional control strategies. In addition, The main theme is to design a robust control scheme having faster dynamic response, reliable operation for parameter uncertainties and speed variation, and maximized torque and efficiency of the IM. The test bench of the IM control has three main parts: IM model, Inverter Model, and control structure. The IM is modelled in synchronous frame using 𝑑𝑞 modelling while the Space Vector Pulse Width Modulation (SVPWM) technique is used for modulation of the inverter. Our proposed controllers are critically analyzed and compared with the PI controller considering different conditions: parameter uncertainties, speed variation, load disturbances, and under electrical faults. In addition, the results validate the effectiveness of the designed controllers and are then related to former works.

LINK:

http://www.riss.kr/search/detail/DetailView.do?p_mat_type=be54d9b8bc7cdb09&control_no=0b81d8311912ba79ffe0bdc3ef48d419

DOWNLOAD: https://www.mediafire.com/file/bi9u9l53mma4kqm/Advanced+Control+Design+for+Grid-Connected.pdf/file

Control Design of a Single-Phase DC/AC Inverter for PV Applications--By Haoyan Liu University of Arkansas, Fayetteville

 Control Design of a Single-Phase DC/AC Inverter for PV Applications 

 A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Electrical Engineering by Haoyan Liu 

Harbin University of Science and Technology Bachelor of Engineering in Automation, 2012 

 University of Arkansas, Fayetteville 

 Abstract

 This thesis presents controller designs of a 2 kVA single-phase inverter for photovoltaic (PV) applications. The demand for better controller designs is constantly rising as the renewable energy market continues to rapidly grow. Some background research has been done on solar energy, PV inverter configurations, inverter control design, and hardware component selection. Controllers are designed both for stand-alone and grid-connected modes of operation. For standalone inverter control, the outer control loop regulates the filter capacitor voltage. Combining the synchronous frame outer control loop with the capacitor current feedback inner control loop, the system can achieve both zero steady-state error and better step load performance. For grid-tied inverter control, proportional capacitor current feedback is used. This achieves the active damping needed to suppress the LCL filter resonance problem. The outer loop regulates the inverter output current flowing into the grid with a proportional resonant controller and harmonic compensators. With a revised grid synchronization unit, the active power and reactive power can be decoupled and controlled separately through a serial communication based user interface. To validate the designed controllers, a scaled down prototype is constructed and tested with a digital signal processor (DSP) TMS320F28335. 

 LINK DOWNLOAD: 

https://www.mediafire.com/file/enicagmrbm111g7/Control+Design+of+a+Single-Phase+DCAC+Inverter.pdf/file

Topologia de transformador de estado sólido baseado no conversor LLC com célula auxiliar para controle do valor eficaz da tensão de saída-Nascimento, Kaio Cesar Maciel---Dissertação submetida ao Programa de Pós-Graduação em Engenharia Elétrica da Universidade Federal de Santa Catarina

Título: Topologia de transformador de estado sólido baseado no conversor LLC com célula auxiliar para controle do valor eficaz da tensão de saída 

Autor: Nascimento, Kaio Cesar Maciel

 Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Elétrica, Florianópolis, 2020-BRASIL.

 Resumo:

 O presente trabalho propõe uma topologia de Transformador de Estado Sólido CA-CA com regulação do valor eficaz da tensão de saída. A entrada do conversor é composta por um estágio Folder, responsável por prover em sua saída o módulo do valor de tensão aplicada à sua entrada. À saída desse estágio são conectados dois módulos na configuração IPOS (Input-Series Output-Parallel). O primeiro é composto por um conversor ressonante LLC. O segundo é composto por um conversor Buck síncrono em série com outro conversor LLC. Os LLC?s operam em frequência fixa e com comutação suave em todos os interruptores, o quais são responsáveis por proporcionar a isolação galvânica em um link de alta frequência. A proposta é que o valor eficaz da tensão de saída seja controlado pela razão cíclica do conversor Buck. É apresentado um estudo das características estáticas da topologia, metodologia de projeto, e resultados experimentais. Para tal foi projetado um protótipo de 2kW, 220V/220V e um ajuste ±10% do valor nominal da tensão de saída e medido um valor máximo de eficiência de 96,67%.

 Abstract: 

The present work proposes a topology of a Solid State Transformer CA-CA capable of regulating the effective value of the output voltage. The front-end of the converter is composed by a stage that rectifies the voltage without producing a DC level, responsible for providing on its output the module of the voltage value applied at the input. Two modules are connected in the IPOS (Input-Series Output-Parallel) configuration on the output of this stage. The first one consists in a resonant LLC converter and the second one consists in a synchronous Buck converter, in series with another LLC converter. The LLC operates at fixed frequency and with soft commutation on all switches, these are responsible for the galvanic isolation on a high frequency link. The proposal regards control the RMS value of the output voltage by modifying the duty cycle of the Buck converter. A study of the static characteristics of the topology, design methodology, and experimental results are presented. For this purpose, it was designed a 2kW 220V/220V prototype, with ±10% adjustment of its output voltage and a maximum efficiency value of 96.67% was measured. 

LINK: https://repositorio.ufsc.br/handle/123456789/219556

Conversor série ressonante bidirecional operando como transformador de estado sólido-Autor:Pacheco, Leonardo Freire-Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Elétrica, Florianópolis, 2019.

 Pacheco, Leonardo Freire Conversor série ressonante bidirecional operando como transformador de estado sólido / Leonardo Freire Pacheco ; orientador, Ivo Barbi, 2019. 310 p. D

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós Graduação em Engenharia Elétrica, Florianópolis, 2019.

RESUMO 

É apresentado nessa dissertação o estudo e implementação de uma topologia de Transformador de Estado Sólido baseado num derivado do Conversor Série Ressonante: o LLC Ressonante. Este conversor tem em sua entrada tensão alternada e fornece em sua saída tensão alternada em fase, assim como um transformador convencional. Possui isolação galvânica e nível de tensão ajustável através do número de espiras do transformador, porém possui peso e volume reduzido em relação aos transformadores convencionais, por ser um transformador de média frequência. Inicialmente, apresenta-se uma contextualização sobre Transformadores de Estado Sólido, seguido de fundamentação teórica sobre Conversores Série Ressonantes e LLC Ressonantes. Em seguida, o projeto e dimensionamento dos elementos presentes na topologia é feito com base na potência nominal determinada. Devido ao efeito da ressonância, os elementos semicondutores da estrutura comutam de forma não-dissipativa, e para garantir a comutação suave, devem ser empregados sensores de tensão e corrente, além da implementação de tempo morto entre acionamento de interruptores complementares. A estratégia de comutação adotada é capaz de processar energia para cargas resistivas, bem como para cargas com propriedades indutivas, tais como motores, entretanto não foram obtidos resultados experimentais para tal caso. Por ser um Conversor LLC Ressonante, suas propriedades o tornam passivo de ganho em sua tensão de saída modificando apenas a frequência de comutação dos seus interruptores. Após o estudo e simulação de toda a topologia, é apresentado o desenvolvimento de um protótipo com potência nominal de 2 kW, com valor eficaz de tensão de entrada de 220 V e frequência de 60 Hz. Finalmente, a análise teórica e as simulações são validadas através de resultados experimentais, mostrando a eficácia do conversor e sua operação como um Transformador de Estado Sólido. Observa-se que a topologia possui vantagens, tais como relativamente poucos interruptores, ajuste amplo de tensão de saída através do número de espiras do transformador, ajuste fino de tensão de saída através da frequência de comutação, e peso e volume reduzidos. 

ABSTRACT 

This paper presents the study and implementation of a Solid State Transformer topology based on a Resonant Series Converter derivative: Resonant LLC. This converter has sinusoidal voltage in its input and provides in its output sinusoidal voltage in phase, just like a conventional transformer. It has galvanic isolation and adjustable voltage level through the number of turns of the transformer, but it has a reduced weight and volume compared to conventional transformers, because it is a medium frequency transformer. Initially, a theoretical basis is presented on Resonant Series Converters and Resonant LLCs, followed by contextualization on Solid State Transformers. Then, the design and dimensioning of the elements present in the topology is done based on the determined rated power. Due to the resonance effect, the semiconductor elements of the structure switch non-dissipative, and to ensure soft switching, voltage and current sensors must be employed, in addition to the implementation of dead time between the activation of complementary switches. The adopted switching strategy is able to process energy for resistive loads, as well as for loads with inductive properties, such as motors, however no experimental results were obtained for this case. Because it is a Resonant LLC Converter, its properties make it possible to gain its output voltage by modifying only the switching frequency of its switches. After the study and simulation of the entire topology, the development of a prototype with a nominal power of 2 kW, with an input voltage effective value of 220 V and a frequency of 60 Hz is presented. Finally, the theoretical analysis and the simulations are validated through experimental results, showing the efficiency of the converter and its operation as a Solid State Transformer. It is observed that the topology has advantages such as relatively few switches, wide adjustment of output voltage through the number of turns of the transformer, fine adjustment of output voltage through the switching frequency, and reduced weight and volume.

LINK: https://repositorio.ufsc.br/bitstream/handle/123456789/214315/PEEL1874-D.pdf?sequence=-1&isAllowed=y

The Forrest Mims Engineers Notebook

The book features: carefully hand-drawn circuit illustrations hundreds of fully tested circuits tutorial on electronics basics tips on part substitutions, design modifications, and circuit operation All covering the following areas: Review of the Basics Digital Integrated Circuits MOS/CMOS Integrated Circuits TTL/LS Integrated Circuits Linear Integrated Circuits Index of Integrated Circuits Index of Circuit Applications

LINK: https://www.zpag.net/Electroniques/Kit/TheForrestMimsEngineersNotebook.pdf

LINK: https://archive.org/details/Forrest_Mims-engineers_mini-notebook_555_timer_circuits_radio_shack_electronics/mode/2up