Design and analysis of three phase inverter based Solar PV powered single switch Buck-Boost converter with reduced THD for industrial applications

The development of economical and sustainable eco-friendly renewable source powered power electronic converters have become more attractive in various areas such as automotive, household and industrial applications etc., Bucking and boosting of voltage according to the requirement is also much needed. So, this work proposes a solar PV powered single switch buck-boost converter which reduces implementation cost, minimal voltage and current stress across the capacitors and diodes and less switching power losses. The work structure comprises of solar PV source with modified P and O algorithm based MPPT, single switch buck-boost dc-dc converter, battery backup to store excess energy, three phase inverter with sinusoidal PWM to find optimal switching angles for harmonic control and 3Φ induction motor load. Here reduction of THD is applied to the line to line voltage of the inverter. Performance analysis of the proposed circuit is done using MATLAB/SIMULINK platform. A detailed steady state analysis of the dc-dc converter topology is also analyzed to system stability. The proposed single switch buck-boost converter is designed to provide an output voltage and current of 363V, 45.5A DC from 520V, 35A PV array. The designed converter is then employed to run a three phase full bridge inverter with 440V, 15A AC. From the simulation results, it is found that the solar powered single switch buck-boost with MPPT is stable, efficient with minimal losses and less THD with better quality output

INTEGRATED GREEN SUBMERSIBLE PUMPING SYSTEM FOR FUTURE GENERATION

In the system solar power has been used for cultivation. Solar photovoltaic cells convert solar energy into electricity through solar photovoltaic (SPV) effect. Generated DC voltage then converted in to AC voltage by pump controller, this AC voltage is used as the input of Variable Frequency Drive (VFD).  The VFD acts as a motor controller that controls the submersible pump motor by varying the frequency and voltage of its input power supply.  The VFD is associated with pump controller. Regulated three phase AC voltage is the output of the pump controller which is directly connected with submersible pump. The water thus drawn from bore wells by a solar water pump is pumped to supply for irrigation purpose as required. This system is full off-grid interfaced system appropriate for the village areas. The main goal of this system is to use solar energy at a minimum running cost. The solar powered project is completely eco friendly and the plant is relatively clean with small maintenance. This project helps to reduce the cost of electricity, as well as minimize the overall agricultural cost

Design of a single-switch DC/DC converter for a PV-battery-powered pump system with PFM+PWM control

© 2014 IEEE. A single-switch nonisolated dc/dc converter for a stand-alone photovoltaic (PV)-battery-powered pump system is proposed in this paper. The converter is formed by combining a buck converter with a buck-boost converter. This integration also resulted in reduced repeated power processing, hence improving the conversion efficiency. With only a single transistor, the converter is able to perform three tasks simultaneously, namely, maximum-power-point tracking (MPPT), battery charging, and driving the pump at constant flow rate. To achieve these control objectives, the two inductors operate in different modes such that variable switching frequency control and duty cycle control can be used to manage MPPT and output voltage regulation, respectively. The battery in the converter provides a more steady dc-link voltage as compared to that of a conventional single-stage converter and hence mitigates the high voltage stress problem. Experimental results of a 14-W laboratory prototype converter with a maximum efficiency of 92% confirmed the performance of the proposed converter when used in a PV-battery pump system

Design and implementation of multi-port DC-DC converters for electrical power systems

The thesis proposes developing, analysing, and verifying these DC-DC converters to improve the current state-of-the-art topology. Four new DC-DC converters for applications like light emitting diode, lighting microgrids DC, PV applications, and electric vehicles are as follows. In this study, the two-input converter is presented. The two-input converter that has been proposed serves as the interface between the two input sources and load. Using two switches and two diodes, the proposed converter minimises switching losses and contains eight components in total, making it compact and low volume. As a result, the highest average efficiency is 92.5%, and the lowest is 89.6%. In this research, the new three-port converter that has been proposed serves as the interface between the input source, a battery, and a load. In addition, the converter is suitable for use in standalone systems or satellite applications. A low-volume converter is designed with three switches and two diodes, thereby minimizing switching losses and ten components in total. Regarding efficiency, the highest average is 92.5%, and the lowest is 90.9%. Also, this study proposes a single-switch high-step-up converter for LED drivers and PV applications. A further benefit of the proposed converter over conventional classical converters is that it utilises only one active switch. These results align with simulation results, and its gain is 6.8 times greater than classical converters. Furthermore, stress across switches and diodes is smaller than the output voltage, approximately 50%. Semiconductor losses were limited with a low duty cycle of 0.7. This makes the highest average efficiency 95% and the lowest 93.9%. The new four-port converter is presented for applications such as microgrid structures and electric vehicles. As part of the integrated converter, two or three converters are combined by sharing some components, such as switches, inductors, and capacitors, to form a single integrated converter. As a result of the four-port converter proposed, battery power can be managed, and output voltage can be regulated simultaneously

Topology Derivation and Development of Non-Isolated Three-port Converters for DC Microgrids

Currently, three-port converters (TPCs) are gaining popularity in applications which integrate renewable energies, such as photovoltaics and wind, and energy storage elements, such as batteries and supercapacitors with load. This is due to the advantages of a single power conversion stage between any two ports for better conversion efficiency and a highly integrated structure for compactness. Most of the reported TPCs focus on the consuming load. However, there are applications such as hybrid-electric vehicle braking systems and DC microgrids which have power generating capability. A typical example is battery charging in a DC microgrid. When the photovoltaics has inadequate power to charge the battery, the TPCs that consider only consuming load need an extra DC/DC converter for the DC bus to charge the battery. Three-winding transformers associated with full-bridge configurations as the basis for TPCs can fulfill the purpose of bi-directional power flow between any two ports. However, bulkiness of transformers and the need for more switches and associated control mechanisms increases the converter complexity, volume and cost. Solutions for integrating a regenerative load in NITPCs are still limited. This research work focuses on the development of non-isolated three-port converters (NITPCs), as they are capable of driving a regenerative load while offering a compact solution. The study includes a systematic approach to deriving a family of NITPCs. They combine different commonly known power converters in an integrated manner while considering the voltage polarity, voltage levels among the ports and overall voltage conversion ratio. The derived converter topologies allow for all possible power flow combinations among the sources and load while preserving the single power processing feature of the TPC. A design example of a boost converter based TPC with a bi-directional buck converter is reported. In addition, a novel single-inductor NITPC is proposed. It is a further integrated topology according to the aforementioned design example where only one inductor is required instead of two, and the number of power transistors remains the same. The detailed topological derivation, operation principles, steady-state analysis, simulation results and experiment results are given to verify the proposed NITPCs

독립 신재생 전력망의 에너지 모니터링 및 부하 고려 모델 개발

학위논문 (박사)-- 서울대학교 대학원 공과대학 기계항공공학부, 2017. 8. 안성훈.Demand for renewable energy sources has increased rapidly due to global warming. Since 1990, the renewable energy consumption ratio has increased among developed countries and the OECD average reached over 10% in 2015. Even in developing countries, an off-grid renewable power system has been implemented in rural areas to provide electricity. However, the power generation characteristics of renewable energy sources are so random that power outages occur frequently. In this research, an off-grid monitoring platform was developed and applied to an off-grid renewable energy system to overcome the instability of a renewable power system in rural areas. Our monitoring platform contains a customized real-time operating system with low-cost hardware for task management. The monitoring platform was capable of bidirectionally transmitting a data set via short message service or the internet. The transmitted data set was uploaded to a cloud system so that the off-grid system could be monitored with any platform. The energy consumption of manufacturing systems and renewable energy systems were modeled, and the operating conditions were simulated. The simulation results provided 1) the design guide for an off-grid system, 2) the failure rate with various scales of off-grid systems, and 3) the calculation method of operation times. Furthermore, the modeling method could be applied to various types of electric load conditions. Finally, an off-grid test bed was installed with our developed monitoring platform and four case studies were conducted: 1) a three dimensional printer, 2) a turning machine, 3) a band saw, and 4) a vaccine carrier, to verify the stability of the off-grid energy system with manufacturing processes. Comparison with previous research was also conducted, and the proposed simulation method provided a smaller scale of off-grid systems with stable operation.1 INTRODUCTION 1 1.1 OVERVIEW 1 1.2 STABILITY ISSUES IN RENEWABLE ENERGY SYSTEMS 7 1.3 STABILITY ISSUES AND MANUFACTURING PROCESSES 9 2 RENEWABLE ENERGY PRODUCTION MODEL 12 2.1 PV ENERGY PRODUCTION 12 2.2 WIND ENERGY PRODUCTION 19 2.3 BATTERY MODEL 23 2.4 COMBINING MODELS FOR A RENEWABLE ENERGY PLANT 28 2.5 OPERATION TIME CALCULATIONS 29 2.6 CONCLUSIONS 31 3 MANUFACTURING ENERGY CONSUMPTION MODEL 32 3.1 OVERVIEW 32 3.2 THEORETICAL BACKGROUNDS ON MANUFACTURING ENERGY CONSUMPTION 35 3.3 STANDARDIZED ENERGY CONSUMPTION MEASUREMENT PROCEDURE 43 3.4 RESULTS 51 3.5 ENERGY CONSUMPTION SIMULATOR 57 3.6 MACHINE LEARNING-BASED ENERGY CONSUMPTION MODELING 68 3.7 SUMMARY 75 4 ENERGY MODEL FOR RENEWABLE ENERGY AND MANUFACTURING PROCESSES 76 4.1 OVERVIEW 77 4.2 ASSUMPTIONS OF MODELS 79 4.3 GENERALIZED LOAD CONDITION 81 4.4 TEST BED FOR MODEL 84 4.5 MODELING RESULTS 88 4.6 SUMMARY 114 5 CONCLUSIONS 116 APPENDIX 118 6 BIBLIOGRAPHY 145 7 ABSTRACT IN KOREAN 154Docto