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Single Stage Soft Switched High Frequency Transformer Isolated Ac To Dc Bridge Converter And Extension To Multiphase Converter
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Book Synopsis Single Stage Soft-switched High-frequency Transformer Isolated AC-to-DC Bridge Converter and Extension to Multiphase Converter by : M. M. Azizur Rahman
Download or read book Single Stage Soft-switched High-frequency Transformer Isolated AC-to-DC Bridge Converter and Extension to Multiphase Converter written by M. M. Azizur Rahman and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents the operation, analysis, simulation and experimental results of a single-phase single-stage soft-switched high frequency (HF) transformer isolated ac-to-dc bridge converter with low total harmonic distortion (THD) and its extension to ac-to-dc multiphase converter. A single-phase single-stage soft-switched ac-to-dc bridge converter cell has been proposed based on a new gating scheme. Due to the discontinuous current mode (DCM) operation of the boost inductor, natural power factor correction and low THD are ensured. The single-stage ac-to-dc multiphase converter is realized based on this bridge converter cell to reduce HF harmonic components in the line current. The steady-state operation of the single-stage bridge converter is explained for all operating modes. Intervals of operation in these modes are identified and analyzed. The steady-state solutions are presented. Based on these solutions, design curves are obtained. Design example of a 1.7 kW converter is presented to illustrate the design procedure. Operational characteristics are obtained for different line and load conditions. PSPICE simulation results for the designed converter are presented. An experimental prototype is built to verify the operation and performance of the converter. All four switches in the fixed frequency bridge converter undergo soft switching (common switch requires an auxiliary circuit) for a wide line and load range. A single-stage HF transformer isolated ac-to-dc multiphase converter is proposed. The analyses of the single-stage bridge converter cell are extended to the multiphase converter. It is shown that N = 3 is near the optimum number of cells to reduce the input current HF harmonic components. A design example of a 166 to 260 V (rms) input, 420 V output, 5 kW converter switching at 50 kHz is presented. PSPICE simulation results are obtained for the designed converter to study its performance for varying load and line conditions. A 3-cell 1.5 kW experimental prototype is built and experimental results are obtained. All the results show that HF harmonics in the line current are reduced and output voltage ripple frequency is increased. Each cell handles equal power and all bridge-switches are soft switched. As a result, uniform thermal distribution is obtained. Small-signal analysis of the single-stage ac-to-dc bridge converter cell is presented for all operating modes using state-space averaging technique. Based on this analysis, small signal transfer functions are obtained. Frequency response of the transfer functions are plotted using MATLAB program and verified by PSPICE simulation results. A closed loop control system is designed and frequency response of the overall loop gain is presented. Large-signal transient behavior of the converter cell is studied with open loop using PSPICE simulation program for step change in line and load conditions. The simulation results show that the closed loop system is required to improve the converter performance during step increase in line voltage.
Book Synopsis Soft-switched High-frequency Transformer Isolated Single-cell DC-to-DC and Multi-cell AC-to-DC Converters Controlled with a New Gating Scheme Implemented on FPGA by : Fei Luo
Download or read book Soft-switched High-frequency Transformer Isolated Single-cell DC-to-DC and Multi-cell AC-to-DC Converters Controlled with a New Gating Scheme Implemented on FPGA written by Fei Luo and published by . This book was released on 2005 with total page 350 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents the operational principles, and analysis, simulation. experimental results of a single-cell full-bridge high frequency (HF) transformer isolated DC-to-DC power converter with an inductive output filter controlled with a new gating scheme. A single-stage multi-cell HF transformer isolated AC-to-DC power converter with the same new gating scheme is designed and tested. The new gating scheme is implemented in a Field-programmable gate-array (FPGA) chip to generate the control gating signals for the DC-to-DC and AC-to-DC converters. The steady-state operation of the DC-to-DC converter controlled with the new gating scheme is analyzed using the equivalent circuits during different intervals of operation. Based on the operational analysis, a set of equations is derived to draw design curves. A design example of 5 kW, 580 V to 620 V input and 420 V output DC-to-DC converter is given to present the design procedure. PSPICE simulation and experimental results obtained from an experimental converter controlled with the FPGA are provided to verify the theoretical analysis, and design procedure. A systematical procedure for finding the parameters of the output RCD snubber circuit is also given. A 3 kW 3-cell 166 V to 260 V input 420 V output single-stage HF transformer isolated AC-to-DC multi-cell converter is designed and tested using a FPGA controllerThe new gating scheme is implemented on a Xilinx Spartan 11 FPGA chip using two digital pulse-width modulation (DPWM) approaches, the conventional DPWM module and the delay-line DPWM module. The simulation and experimental results are presented.
Book Synopsis Soft-switched High-frequency Transformer Isolated Single-cell DC-to-DC and Multi-cell AC-to-DC Converters Controlled with a New Gating Scheme Implemented on FPGA. by :
Download or read book Soft-switched High-frequency Transformer Isolated Single-cell DC-to-DC and Multi-cell AC-to-DC Converters Controlled with a New Gating Scheme Implemented on FPGA. written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents the operational principles, and analysis, simulation. experimental results of a single-cell full-bridge high frequency (HF) transformer isolated DC-to-DC power converter with an inductive output filter controlled with a new gating scheme. A single-stage multi-cell HF transformer isolated AC-to-DC power converter with the same new gating scheme is designed and tested. The new gating scheme is implemented in a Field-programmable gate-array (FPGA) chip to generate the control gating signals for the DC-to-DC and AC-to-DC converters. The steady-state operation of the DC-to-DC converter controlled with the new gating scheme is analyzed using the equivalent circuits during different intervals of operation. Based on the operational analysis, a set of equations is derived to draw design curves. A design example of 5 kW, 580 V to 620 V input and 420 V output DC-to-DC converter is given to present the design procedure. PSPICE simulation and experimental results obtained from an experimental converter controlled with the FPGA are provided to verify the theoretical analysis, and design procedure. A systematical procedure for finding the parameters of the output RCD snubber circuit is also given. A 3 kW 3-cell 166 V to 260 V input 420 V output single-stage HF transformer isolated AC-to-DC multi-cell converter is designed and tested using a FPGA controller The new gating scheme is implemented on a Xilinx Spartan 11 FPGA chip using two digital pulse-width modulation (DPWM) approaches, the conventional DPWM module and the delay-line DPWM module. The simulation and experimental results are presented.
Book Synopsis Soft-switched High-frequency Transformer Isolated Single-cell DC-to-DC and Multi-cell AC-to-DC Converters Controlled with a New Gating Scheme Implemented on FPGA by : Fei Luo
Download or read book Soft-switched High-frequency Transformer Isolated Single-cell DC-to-DC and Multi-cell AC-to-DC Converters Controlled with a New Gating Scheme Implemented on FPGA written by Fei Luo and published by . This book was released on 2005 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents the operational principles, and analysis, simulation. experimental results of a single-cell full-bridge high frequency (HF) transformer isolated DC-to-DC power converter with an inductive output filter controlled with a new gating scheme. A single-stage multi-cell HF transformer isolated AC-to-DC power converter with the same new gating scheme is designed and tested. The new gating scheme is implemented in a Field-programmable gate-array (FPGA) chip to generate the control gating signals for the DC-to-DC and AC-to-DC converters. The steady-state operation of the DC-to-DC converter controlled with the new gating scheme is analyzed using the equivalent circuits during different intervals of operation. Based on the operational analysis, a set of equations is derived to draw design curves. A design example of 5 kW, 580 V to 620 V input and 420 V output DC-to-DC converter is given to present the design procedure. PSPICE simulation and experimental results obtained from an experimental converter controlled with the FPGA are provided to verify the theoretical analysis, and design procedure. A systematical procedure for finding the parameters of the output RCD snubber circuit is also given. A 3 kW 3-cell 166 V to 260 V input 420 V output single-stage HF transformer isolated AC-to-DC multi-cell converter is designed and tested using a FPGA controllerThe new gating scheme is implemented on a Xilinx Spartan 11 FPGA chip using two digital pulse-width modulation (DPWM) approaches, the conventional DPWM module and the delay-line DPWM module. The simulation and experimental results are presented.
Book Synopsis High Frequency Transformer Isolated Soft-switched Hybrid Phase Modulated DC-to-DC Converters by : Sriram Jala
Download or read book High Frequency Transformer Isolated Soft-switched Hybrid Phase Modulated DC-to-DC Converters written by Sriram Jala and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis deals with hybrid phase modulated converter with inductive output filter as well as capacitive output filter. The operational principles, detailed steady-state analysis for different modes of operation, detailed design procedure with an example. simulation and experimental results are presented for HPMC with inductive output filter. HPMC with inductive output filter has reduced output filter requirements and maintains ZVS for wide line and load variations. This converter suffers from duty cycle loss and output rectifier ringing requiring secondary-side snubbers and higher voltage rated rectifier diodes. To overcome this problem, a hybrid phase modulated DC-DC converter with a capacitive output filter is proposed. Different modes of operation of the proposed converter are identified and a detailed steady-state analysis for these modes of operation is presented. A design example of 200 W, 22 V to 41 V input voltage and 350 V output voltage hybrid phase modulated converter with inductive and capacitive output filter is given to present the design procedure. Simulation and experimental results obtained from the laboratory prototype are provided to verify the performance of the converter. A comparison of performance between the HPMC with inductive and capacitive output filters with standard phase-shifted PWM full bridge converter are also presented.
Book Synopsis High Frequency Transformer Isolated Soft-switched Hybrid Phase Modulated DC-to-DC Converters by :
Download or read book High Frequency Transformer Isolated Soft-switched Hybrid Phase Modulated DC-to-DC Converters written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis deals with hybrid phase modulated converter with inductive output filter as well as capacitive output filter. The operational principles, detailed steady-state analysis for different modes of operation, detailed design procedure with an example. simulation and experimental results are presented for HPMC with inductive output filter. HPMC with inductive output filter has reduced output filter requirements and maintains ZVS for wide line and load variations. This converter suffers from duty cycle loss and output rectifier ringing requiring secondary-side snubbers and higher voltage rated rectifier diodes. To overcome this problem, a hybrid phase modulated DC-DC converter with a capacitive output filter is proposed. Different modes of operation of the proposed converter are identified and a detailed steady-state analysis for these modes of operation is presented. A design example of 200 W, 22 V to 41 V input voltage and 350 V output voltage hybrid phase modulated converter with inductive and capacitive output filter is given to present the design procedure. Simulation and experimental results obtained from the laboratory prototype are provided to verify the performance of the converter. A comparison of performance between the HPMC with inductive and capacitive output filters with standard phase-shifted PWM full bridge converter are also presented.
Book Synopsis Three-phase High-frequency Transformer Isolated Soft-switching DC-DC Resonant Converters by : Mohamed S. M. Almardy
Download or read book Three-phase High-frequency Transformer Isolated Soft-switching DC-DC Resonant Converters written by Mohamed S. M. Almardy and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: There is an increasing demand for power converters with small size, light weight, high conversion efficiency and higher power density. Also, in many applications, there is a need for dc-to-dc converters to accept dc input voltage and provide regulated and/or isolated dc output voltage at a desired voltage level including telecommunications equipment, process control systems, and in industry applications. This thesis presents the analysis, design, simulation and experimental results of three-phase high-frequency transformer isolated resonant converters. The first converter presented is a three-phase LCC-type dc-dc resonant converter with capacitor output filter including the effect of the magnetizing inductance of the three-phase HF transformer. The equivalent ac load resistance is derived and the converter is analyzed by using approximation analysis approach. Base on this analysis, design curves have been obtained and a design example is given. Intusoft simulation results for the designed converter are given for various input voltage and for different load conditions. The experimental verification of the designed converter performance was established by building a 300 W rated power converter and the experimental results have been given. It is shown that the converter works in zero-voltage switching (ZVS) at various input voltage and different load conditions. A three-phase (LC)(L)-type dc-dc series-resonant converter with capacitive output filter has been proposed. Operation of the converter has been presented using the operating waveforms and equivalent circuit diagrams during different intervals. An approximate analysis approach is used to analyze the converter operation, and design procedure is presented with a design example. Intusoft simulation results for the designed converter are given for input voltage and load variations. Experimental results obtained in a 300 W converter are presented. Major advantages of this converter are the leakage and magnetizing inductances of the high-frequency transformer are used as part of resonant circuit and the output rectifier voltage is clamped to the output voltage. The converter operates in soft-switching for the inverter switches for the wide variations in supply voltage and load and it requires narrow switching frequency variation (compared to LCC-type) to regulate the output voltage. A three-phase high-frequency transformer isolated interleaved (LC)(L)-type dc-dc series-resonant converter with capacitive output filter using fixed frequency control is proposed. The converter operation for different modes is presented using the operating waveforms and equivalent circuit diagrams during different intervals. This converter is modeled and then analyzed using the approximate complex ac circuit analysis approach. Based on the analysis, design curves were obtained and the design procedure is presented with a design example. The designed converter is simulated using PSIM software to predict the performance of the converter for variations in supply voltage and load conditions. The converter operates in ZVS for the inverter switches with minimum input voltage and loses ZVS for two switches in each bridge for higher input voltages.
Book Synopsis American Doctoral Dissertations by :
Download or read book American Doctoral Dissertations written by and published by . This book was released on 2001 with total page 776 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis A Single Stage Full Bridge Power Factor Corrected AC/DC Converter by : Nasser Ismail
Download or read book A Single Stage Full Bridge Power Factor Corrected AC/DC Converter written by Nasser Ismail and published by . This book was released on 1996 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis New Topologies and Modulation Schemes for Soft-Switching Isolated DC–DC Converters by : Zhiqiang Guo
Download or read book New Topologies and Modulation Schemes for Soft-Switching Isolated DC–DC Converters written by Zhiqiang Guo and published by Springer Nature. This book was released on 2019-09-20 with total page 243 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a series of new topologies and modulation schemes for soft-switching in isolated DC–DC converters. Providing detailed analyses and design procedures for converters used in a broad range of applications, it offers a wealth of engineering insights for researchers and students in the field of power electronics, as well as stimulating new ideas for future research.
Book Synopsis Soft Commutation Isolated DC-DC Converters by : Ivo Barbi
Download or read book Soft Commutation Isolated DC-DC Converters written by Ivo Barbi and published by Springer. This book was released on 2018-08-27 with total page 325 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes the operation and analysis of soft-commutated isolated DC–DC converters used in the design of high efficiency and high power density equipment. It explains the basic principles behind first- and second-order circuits with power switches to enable readers to understand the importance of these converters in high efficiency and high power density power supply design for residential, commercial, industrial and medical use as well as in aerospace equipment. With each chapter featuring a different power converter topology, the book covers the most important resonant converters, including series resonant converters; resonant LLC converters; soft commutation pulse width modulation converters; zero voltage switching; and zero current switching. Each topic is presented with full analysis, a showcase of the power stages of the converters, exercises and their solutions as well as simulation results, which mainly focus on the commutation analysis and output characteristic. This book is a valuable source of information for professionals working in power electronics, power conversion and design of high efficiency and high power density DC–DC converters and switch mode power supplies. The book also serves as a point of reference for engineers responsible for development projects and equipment in companies and research centers and a text for advanced students.
Book Synopsis Solid State Transformer by : Fouad Sabry
Download or read book Solid State Transformer written by Fouad Sabry and published by One Billion Knowledgeable. This book was released on 2022-08-31 with total page 758 pages. Available in PDF, EPUB and Kindle. Book excerpt: What Is Solid State Transformer In actuality, an AC-to-AC converter, also known as a solid-state transformer (SST), power electronic transformer (PET), or electronic power transformer, is a type of electric power converter that replaces a conventional transformer in AC electric power distribution. This type of electric power converter is known as an AC-to-AC converter. Because it works at a higher frequency, this kind of transformer is more complicated than a traditional transformer that uses the utility frequency, but it also has the potential to be more space-efficient and smaller than a traditional transformer. The two primary varieties are referred to as "real" AC-to-AC converters and AC-to-DC-to-DC-to-AC converters, respectively. The AC-to-AC converter or DC-to-DC converter that is often found inside of a solid-state transformer is really a transformer. This transformer is what provides the electrical isolation and carries the entire power. This transformer is more compact because the DC-DC inverting stages that occur between the transformer coils are on the smaller side. As a result, the transformer coils that are needed to step up or step down voltages are also on the smaller side. Active regulation of voltage and current may be performed via a solid-state transformer. There are several that are able to convert electricity from single-phase to three-phase and vice versa. The amount of conversions that need to take place may be decreased by having variations that can either input or output DC power. This results in increased end-to-end efficiency. A Modular Solid-state transformer is similar to a Multi-level converter in that it is made up of numerous high-frequency transformers and has the same function. Because it is an intricate electrical circuit, it has to be constructed such that it can survive surges of various kinds, such as lightning. The solid-state transformer is a relatively new kind of transformer. How You Will Benefit (I) Insights, and validations about the following topics: Chapter 1: Solid-state transformer Chapter 2: Power factor Chapter 3: Rectifier Chapter 4: Power supply Chapter 5: Power inverter Chapter 6: Switched-mode power supply Chapter 7: DC-to-DC converter Chapter 8: Voltage regulator Chapter 9: Power electronics Chapter 10: Motor?generator Chapter 11: Rotary converter Chapter 12: HVDC converter station Chapter 13: Variable-frequency drive Chapter 14: Index of electrical engineering articles Chapter 15: H-bridge Chapter 16: Phase converter Chapter 17: Voltage converter Chapter 18: Induction heater Chapter 19: Transformer types Chapter 20: Electric machine Chapter 21: Glossary of electrical and electronics engineering (II) Answering the public top questions about solid state transformer. (III) Real world examples for the usage of solid state transformer in many fields. (IV) 17 appendices to explain, briefly, 266 emerging technologies in each industry to have 360-degree full understanding of solid state transformer' technologies. Who This Book Is For Professionals, undergraduate and graduate students, enthusiasts, hobbyists, and those who want to go beyond basic knowledge or information for any kind of solid state transformer.
Book Synopsis Three-level Soft-switched DC-to-DC Converter and Single-phase, Single-stage, Three-level AC-to-DC Converter by : Vimala Dharmarajan
Download or read book Three-level Soft-switched DC-to-DC Converter and Single-phase, Single-stage, Three-level AC-to-DC Converter written by Vimala Dharmarajan and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Three-level Soft-switched DC-to-DC Converter and Single-phase, Single-stage, Three-level AC-to-DC Converter by :
Download or read book Three-level Soft-switched DC-to-DC Converter and Single-phase, Single-stage, Three-level AC-to-DC Converter written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis proposes a three-level DC-to-DC converter with capacitive output filter and its extension to single-phase, single-stage, three-level AC-to-DC converter with capacitive output filter. The AC-to-DC converter integrates a three-level boost converter operating in discontinuous conduction mode (DCM) and a three-level half-bridge DC-to-DC converter with capacitive output filter. The steady-state operation of the DC-to-DC converter and AC-to-DC converter with capacitive output filter are studied with phase-shifted gating scheme. The three-level topology reduces the voltage rating of the switches to half of the input voltage. Soft-switching is achieved for switches at different load and input voltage conditions. Boost section of the AC-to-DC converter achieves automatic power factor correction (PFC). At reduced load and higher input voltage conditions, the line current Total Harmonic Distortion (THD) increases with phase-shifted gating scheme. The THD has been reduced by using a complementary PWM gating control in the AC-to-DC converter.
Book Synopsis Three-phase AC-to-DC Soft-switching HF Transformer Isolated Converters with Power Factor Correction and Low Harmonic Distortion by :
Download or read book Three-phase AC-to-DC Soft-switching HF Transformer Isolated Converters with Power Factor Correction and Low Harmonic Distortion written by and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Dynamic Carrier Pulse-positioning for Single-stage Isolated AC-DC Converter by : Ambegoda Liyanage Vishwa Perera
Download or read book Dynamic Carrier Pulse-positioning for Single-stage Isolated AC-DC Converter written by Ambegoda Liyanage Vishwa Perera and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The transportation sector is gaining much more attention towards all-electric modes such as electric vehicles (EV), and more electric aircrafts and ships. EVs lead the transportation sector with luxurious, high performance, and intelligent vehicles. The stored battery energy is the most important factor for the operation of the whole vehicle and therefore, EV battery chargers play an important role in the electric transportation sector. High frequency isolated battery charger converters are much preferred in the industry as they provide electrical isolation and reduce magnetic component size. Phase shifted pulse width modulation is commonly used in transformer isolated converters for high frequency power transfer. Generally, the voltage waveforms are phase shifted no more than 45 degrees for grid connected converter applications. In grid connected applications, the high frequency pulse widths (180° to minimum determined by modulation index) may vary when controlling the grid current. If, for certain duration of the low frequency reference signal, the pulse widths are smaller than the externally-commanded phase shift, the pulses would be completely separated. Under these conditions, unwanted reactive content is generated in the converter increasing the high frequency rms current hence increasing conduction losses. An original concept is proposed to lower the reactive content of the high frequency current by positioning the transformer primary and secondary voltage pulses next to each other whenever the phase shift is larger than the pulse width. The voltage pulses are positioned appropriately in each carrier cycle throughout the entire low frequency reference signal. This concept which is referred to as reference-based pulse position (RPP) allows the operation of the converter beyond 45 degree limit and up to 90 degrees allowing for more power output. The concept is tested on an isolated single-stage bidirectional three-phase ac-dc converter which conducts both low frequency grid current and high frequency transformer current. The grid side or the primary of the converter generates the high frequency transformer voltage when controlling the grid current. The switches in the secondary side are then controlled in such a way in each carrier cycle as to coordinate with primary voltage waveform to minimize the reactive content of the high frequency current. The power is transferred utilizing the transformer interlimb leakage inductance. The transformer windings are connected so that the 60Hz grid current does not produce flux in the core leaving only the high frequency flux. Therefore, the size of the magnetics can be reduced which favors a compact design. Furthermore, the dc link utilization is maximized by injecting the third harmonic into the sine reference signals which lowers the dc link requirement by 15%.
Book Synopsis Dual Active Bridge Converters in Solid State Transformers by : Hengsi Qin
Download or read book Dual Active Bridge Converters in Solid State Transformers written by Hengsi Qin and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "This dissertation presents a comprehensive study of Dual Active Bridge (DAB) converters for Solid State Transformers (SSTs). The first contribution is to propose an ac-ac DAB converter as a single stage SST. The proposed converter topology consists of two active H-bridges and one high-frequency transformer. Output voltage can be regulated when input voltage changes by phase shift modulation. Power is transferred from the leading bridge to the lagging bridge. It analyzes the steady-state operation and the range of zero-voltage switching. It develops a switch commutation scheme for the ac-ac DAB converters. Simulation and experiment results of a scaled down prototype are provided to verify the theoretical analysis. The second contribution is to develop a full-order continuous-time average model for dc-dc DAB converters. The transformer current in DAB converter is purely ac, making continuous-time modeling difficult. Instead, the proposed approach uses the dc terms and 1st order terms of transformer current and capacitor voltage as state variables. Singular perturbation analysis is performed to find the sufficient conditions to separate the dynamics of transformer current and capacitor voltage. Experimental results confirm that the proposed model predicts the small-signal frequency response more accurately. The third contribution addresses the controller design of a dc-dc DAB converter when driving a single-phase dc-ac inverter. It studies the effect of 120 Hz current generated by the single-phase inverter. The limitation of PI-controller is investigated. Two methods are proposed to reduce the voltage ripple at the output voltage of DAB converter. The first method helps the feedback loop with feedforward from inverter, while the second one adds an additional resonance controller to the feedback loop. Theoretical analysis, simulation and experiment results are provided to verify the effectiveness of the proposed methods"--Abstract, leaf iii
