Tổng quan về các bộ biến đổi1.1 Giới thiệu chung1.2 Bộ biến đổi AC/DC1.3 Bộ biến đổi DC/AC1.4 Bộ biến đổi DC/DC1.5 Bộ biến đổi AC/AC Trang 4 IntroductionPower electronics converters use
ĐIỀU KHIỂN CÁC BỘ BIẾN ĐỔI TS Nguyễn Văn Vinh BM Kỹ thuật điện, điện tử (ĐHTL) P.409-A1 ⋄ E: vinhnv@tlu.edu.vn / 131 Nội dung môn học Tổng quan biến đổi Nguyên lý điều khiển cho biến đổi Mơ hình hóa điều khiển biến đổi DC/DC Mơ hình hóa điều khiển biến đổi AC/DC Mơ hình hóa điều khiển biến đổi DC/AC Mơ hình hóa điều khiển hệ thống PV WT / 131 Nội dung môn học Tổng quan biến đổi 1.1 1.2 1.3 1.4 1.5 Giới thiệu chung Bộ biến đổi AC/DC Bộ biến đổi DC/AC Bộ biến đổi DC/DC Bộ biến đổi AC/AC / 131 Introduction Power electronics converters use electronic components based on semiconductor switches operated at different frequency levels from 50 to 60Hz mains frequencies to 100MHz radio frequency In order to optimally support different features of diverse applications, power electronics converters should benefit from different characteristics such as nonisolated/ isolated, voltage-fed/current-fed and hard-switched/soft-switched There are various types of power conversion (AC-DC, DC-AC, DC-DC and AC-AC) applicable to different applications / 131 Introduction Most home appliances (e.g., television and personal computer) connected to the electric grid need an AC-DC converter in their power processing system The vast fields of renewable energy grid-integration and motor drives need DC-AC converters to provide constant/variable AC voltage at the output Many battery-powered devices utilize DC-DC converters to provide the required DC voltage for different loads In addition, DC-DC converters are suitable for maximization of energy harvesting of renewable energy sources like photovoltaics and wind turbines In order to change the voltage or frequency of an alternating current source, AC-AC converters are needed (e.g., light dimmer and mains frequency changer) / 131 Nonisolated / Isolated Nonisolated converters are often preferred in applications that electrical isolation is not a necessity, because they are less bulky and costly, and more efficient and reliable Isolated power converters often use either transformer or coupled inductor for multiple purposes such as voltage level shifting, obtaining multiple outputs, providing galvanic isolation and ground loop avoidance [2ex] / 131 Voltage-Fed / Current-Fed Depending on their input circuitry, power electronics converters can be classified as either voltage- or current-fed converters In voltage-fed converters, a capacitor is connected in parallel with the source so the input voltage cannot change instantly In current-fed converters, an inductor is connected in series with the source so the input current cannot change instantly / 131 Hard-Switched / Soft-Switched Hard-switched converters can produce electro-magnetic interference (EMI) emission as a result of high dv/ dt and di/dt at switch turn ON and turn OFF, which can spread throughout the circuit from the input to the output In addition, a large part of power loss is due to switching power loss in hard-switched converter that can significantly reduce the efficiency of the power converter / 131 Hard-Switched / Soft-Switched Soft-switched converters can reduce the switching stress and hence not produce significant EMI in switching transitions, also the power loss occurred due to highfrequency switching is negligible with zero voltage switching (ZVS) and zero current switching (ZCS) In addition, a large part of power loss is due to switching power loss in hard-switched converter that can significantly reduce the efficiency of the power converter Due to the significant improvement in the development and commercialization of the new wide band gap (WPG) semiconductor switches with fast switching capability and low conduction loss (i.e., SiC and GaN), hard-switched converters are sometimes preferred in order to reduce system complexity and cost / 131 Conversion: Types of Power Converters The main goal of power converters is able to reliably change one form of electrical energy to another form by supplying voltage and current of different magnitude and frequency 10 / 131 The power generation from a PV cell is achieved by exploiting the photovoltaic effect that converts solar energy into electrical energy Photovoltaic effect: (A) structure of a photovoltaic cell creating a depletion region and (B) a photon generating an electron-hole pair in a photovoltaic cell 117 / 131 PV Cell Modeling Figure: Electricals model of a photovoltaic cell, where ℎ𝛾 represents photons 118 / 131 PV Cell Modeling Figure: Model of PV modules built up in MATLAB® using the user-definable block (i.e., S-Function) according to the mathematical model of (9.7): (A) Simulink® model and (B) parameter dialog box for the model A resistor (Load) is connected 119 / 131 PV Cell Modeling Figure: Characteristics of PV modules (MPP: maximum power point, 𝐼 𝑠𝑐 : short circuit current, 𝑉𝑜𝑐 : open circuit voltage, 𝑃𝑚 𝑝 𝑝 : power at the MPP, 𝐼 𝑚 𝑝 𝑝 : current at the MPP, and 𝑉𝑚 𝑝 𝑝 : voltage at the MPP) 120 / 131 Configuration of PV Cells Figure: Physical structure of a PV module consisting of 60 solar PV cells (6 x 10) and its electrical symbols 121 / 131 Control of PV Systems Figure: Photovoltaic power conversion systems DC-DC, DC-AC, and AC-AC converters are widely used in the conversion of solar PV energy 122 / 131 Nội dung mơn học Mơ hình hóa điều khiển hệ thống PV WT 6.1 Mơ hình hóa điều khiển hệ thống PV 6.2 Mơ hình hóa điều khiển hệ thống Wind Turbine 123 / 131 Overview of Wind Turbine Systems Configuration: 124 / 131 Overview of Wind Turbine Systems Control Strategy: 125 / 131 Control of DFIG-Based Wind Turbine System Modeling of DFIG: 126 / 131 Control of DFIG-Based Wind Turbine System Control of Rotor-Side Converter: 127 / 131 Control of DFIG-Based Wind Turbine System Control of Grid-Side Converter: 128 / 131 Control of DFIG-Based Wind Turbine System Simulation Conditions: 129 / 131 Control of DFIG-Based Wind Turbine System Simulation Waveforms: 130 / 131 Thank You For Your Attention! 131 / 131