Stability analysis of switched dc-dc boost converters for integrated circuits

Boost converters are very important circuits for modern devices, especially battery- operated integrated circuits. This type of converter allows for small voltages, such as those provided by a battery, to be converted into larger voltage more suitable for driving integrated circuits. Two regions of operation are explored known as Continuous Conduction Mode and Discontinuous Conduction Mode. Each region is analyzed in terms of DC and small-signal performance. Control issues with each are compared and various error amplifier architectures explored. A method to optimize these amplifier architectures is also explored by means of Genetic Algorithms and Particle Swarm Optimization. Finally, stability measurement techniques for boost converters are explored and compared in order to gauge the viability of each method. The Middlebrook Method for measuring stability and cross-correlation are explored here

One-Quadrant Switched-Mode Power Converters

This article presents the main topics related to one-quadrant power converters. The basic topologies are analysed and a simple methodology to obtain the steady-state output-input voltage ratio is set out. A short discussion of different methods to control one-quadrant power converters is presented. Some of the reported derived topologies of one-quadrant power converters are also considered. Some topics related to one-quadrant power converters such as synchronous rectification, hard and soft commutation, and interleaved converters are discussed. Finally, a brief introduction to resonant converters is given.Comment: 25 pages, contribution to the 2014 CAS - CERN Accelerator School: Power Converters, Baden, Switzerland, 7-14 May 201

Dynamic modeling of pwm and single-switch single-stage power factor correction converters

The concept of averaging has been used extensively in the modeling of power electronic circuits to overcome their inherent time-variant nature. Among various methods, the PWM switch modeling approach is most widely accepted in the study of closed-loop stability and transient response because of its accuracy and simplicity. However, a non-ideal PWM switch model considering conduction losses is not available except for converters operating in continuous conduction mode (CCM) and under small ripple conditions. Modeling of conductor losses under large ripple conditions has not been reported in the open literature, especially when the converter operates in discontinuous conduction mode (DCM). In this dissertation, new models are developed to include conduction losses in the non-ideal PWM switch model under CCM and DCM conditions. The developed model is verified through two converter examples and the effect of conduction losses on the steady state and dynamic responses of the converter is also studied. Another major constraint of the PWM switch modeling approach is that it heavily relies on finding the three-terminal PWM switch. This requirement severely limits its application in modeling single-switch single-stage power factor correction (PFC) converters, where more complex topological structures and switching actions are often encountered. In this work, we developed a new modeling approach which extends the PWM switch concept by identifying the charging and discharging voltages applied to the inductors. The new method can be easily applied to derive large-signal models for a large group of PFC converters and the procedure is elaborated through a specific example. Finally, analytical results regarding harmonic contents and power factors of various PWM converters in PFC applications are also presented here

Bi-directional Dcm Dc-to-dc Converter For Hybrid Electric Vehicles

With the recent revival of the hybrid vehicle much advancement in power management has been made. The most popular hybrid vehicle, the hybrid electric vehicle, has many topologies developed to realize this hybrid vehicle. From these topologies, as sub set was created to define a particular group of vehicles where the converter discussed in this thesis has the most advantage. This sub set is defined by two electric sources of power coupled together at a common bus. This set up presents many unique operating conditions which can be handled seamlessly by the DC-to-DC converter when designed properly. The DC-to-DC converter discussed in this thesis is operated in Discontinuous Conduction Mode (DCM) of operation because of its unique advantages over the Continuous Conduction Mode (CCM) operated converter. The most relevant being the reduction of size of the magnetic components such as inductor, capacitor and transformers. However, the DC-to-DC converter operated in DCM does not have the inherent capability of bi-directional power flow. This problem can be overcome with a unique digital control technique developed here. The control is developed in a hierarchical fashion to separate the functions required for this sub set of hybrid electric vehicle topologies. This layered approach for the controller allows for the seamless integration of this converter into the vehicle. The first and lowest level of control includes a group of voltage and controller regulators. The average and small signal model of these controllers were developed here to be stable and have a relatively fast recovery time to handle the transient dynamics of the vehicle system. The second level of control commands and organizes the regulators from the first level of control to perform high level task that is more specific to the operation of the vehicle. This level of control is divided into three modes called hybrid boost, hybrid buck and electric vehicle mode. These modes are developed to handle the specific operating conditions found when the vehicle is operated in the specific mode. The third level of control is used to command the second level of control and is left opened via a communication area network (CAN) bus controller. This level of control is intended to come from the vehicle s system controller. Because the DC-to-DC converter is operated in DCM, this introduces added voltage ripple on the output voltage as well as higher current ripple demand from the input voltage. Since this is generally undesirable, the converter is split into three phases and properly interleaved. The interleaving operation is used to counteract the effects of the added voltage and current ripple. Finally, a level of protection is added to protect the converter and surrounding components from harm. All protection is designed and implemented digitally in DSP

Dynamic modeling of DC-DC converters with peak current control in double-stage photovoltaic grid-connected inverters

In photovoltaic (PV) double-stage grid-connected inverters a high-frequency DC-DC isolation and voltage step-up stage is commonly used between the panel and the grid-connected inverter. This paper is focused on the modeling and control design of DC-DC converters with Peak Current mode Control (PCC) and an external control loop of the PV panel voltage, which works following a voltage reference provided by a maximum power point tracking (MPPT) algorithm. In the proposed overall control structure the output voltage of the DC-DC converter is regulated by the grid-connected inverter. Therefore, the inverter may be considered as a constant voltage load for the development of the small-signal model of the DC-DC converter, whereas the PV panel is considered as a negative resistance. The sensitivity of the control loops to variations of the power extracted from the PV panel and of its voltage is studied. The theoretical analysis is corroborated by frequency response measurements on a 230 W experimental inverter working from a single PV panel. The inverter is based on a Flyback DC-DC converter operating in discontinuous conduction mode (DCM) followed by a PWM full-bridge single-phase inverter. The time response of the whole system (DC-DC + inverter) is also shown to validate the concept. Copyright © 2011 John Wiley & Sons, Ltd. In photovoltaic (PV) double-stage gridconnected inverters a high-frequency DC-DC isolation and voltage step-up stage is commonly used between the panel and the grid-connected inverter. This paper is focused on the modeling and control design of DC-DC converters with Peak Current mode Control (PCC) and an external control loop of the PV panel voltage, which works following a voltage reference provided by a maximum power point tracking (MPPT) algorithm. The sensitivity of the control loops to variations of the power extracted from the PV panel and of its voltage is studied. Copyright © 2011 John Wiley & Sons, Ltd. Copyright © 2011 John Wiley & Sons, Ltd.This work was supported by the Spanish Ministry of Science and Innovation (MICINN) under grant ENE2009-13998-C02-02. The company AUSTRIAMICROSYSTEMS co-financed this project.Garcerá Sanfeliú, G.; González Medina, R.; Figueres Amorós, E.; Sandía Paredes, J. (2012). Dynamic modeling of DC-DC converters with peak current control in double-stage photovoltaic grid-connected inverters. International Journal of Circuit Theory and Applications. 40(8):793-813. https://doi.org/10.1002/cta.756S793813408Carrasco, J. M., Franquelo, L. G., Bialasiewicz, J. T., Galvan, E., PortilloGuisado, R. C., Prats, M. A. M., … Moreno-Alfonso, N. (2006). Power-Electronic Systems for the Grid Integration of Renewable Energy Sources: A Survey. 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IEEE Transactions on Energy Conversion, 19(4), 748-755. doi:10.1109/tec.2004.827707Femia, N., Petrone, G., Spagnuolo, G., & Vitelli, M. (2009). A Technique for Improving P&O MPPT Performances of Double-Stage Grid-Connected Photovoltaic Systems. IEEE Transactions on Industrial Electronics, 56(11), 4473-4482. doi:10.1109/tie.2009.2029589Chiu, H.-J., Huang, H.-M., Yang, H.-T., & Cheng, S.-J. (2008). An improved single-stage Flyback PFC converter for high-luminance lighting LED lamps. International Journal of Circuit Theory and Applications, 36(2), 205-210. doi:10.1002/cta.404Chiu, H.-J., Yao, C.-J., & Lo, Y.-K. (2009). A DC/DC converter topology for renewable energy systems. International Journal of Circuit Theory and Applications, 37(3), 485-495. doi:10.1002/cta.475Martins DC Demonti R Photovoltaic Energy Processing for Utility Connected System 1292 1296 10.1109/IECON.2001.975968www.focus.ti.com/lit/ml/slup127/slup127.pdf2003 http://www.fairchildsemi.comEsram, T., & Chapman, P. L. (2007). Comparison of Photovoltaic Array Maximum Power Point Tracking Techniques. IEEE Transactions on Energy Conversion, 22(2), 439-449. doi:10.1109/tec.2006.874230Liserre, M., Blaabjerg, F., & Hansen, S. (2005). Design and Control of an LCL-Filter-Based Three-Phase Active Rectifier. IEEE Transactions on Industry Applications, 41(5), 1281-1291. doi:10.1109/tia.2005.853373Liserre, M., Teodorescu, R., & Blaabjerg, F. (2006). Stability of photovoltaic and wind turbine grid-connected inverters for a large set of grid impedance values. IEEE Transactions on Power Electronics, 21(1), 263-272. doi:10.1109/tpel.2005.861185Figueres, E., Garcera, G., Sandia, J., Gonzalez-Espin, F., & Rubio, J. C. (2009). Sensitivity Study of the Dynamics of Three-Phase Photovoltaic Inverters With an LCL Grid Filter. 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High Performance Power Management Integrated Circuits for Portable Devices

abstract: Portable devices often require multiple power management IC (PMIC) to power different sub-modules, Li-ion batteries are well suited for portable devices because of its small size, high energy density and long life cycle. Since Li-ion battery is the major power source for portable device, fast and high-efficiency battery charging solution has become a major requirement in portable device application. In the first part of dissertation, a high performance Li-ion switching battery charger is proposed. Cascaded two loop (CTL) control architecture is used for seamless CC-CV transition, time based technique is utilized to minimize controller area and power consumption. Time domain controller is implemented by using voltage controlled oscillator (VCO) and voltage controlled delay line (VCDL). Several efficiency improvement techniques such as segmented power-FET, quasi-zero voltage switching (QZVS) and switching frequency reduction are proposed. The proposed switching battery charger is able to provide maximum 2 A charging current and has an peak efficiency of 93.3%. By configure the charger as boost converter, the charger is able to provide maximum 1.5 A charging current while achieving 96.3% peak efficiency. The second part of dissertation presents a digital low dropout regulator (DLDO) for system on a chip (SoC) in portable devices application. The proposed DLDO achieve fast transient settling time, lower undershoot/overshoot and higher PSR performance compared to state of the art. By having a good PSR performance, the proposed DLDO is able to power mixed signal load. To achieve a fast load transient response, a load transient detector (LTD) enables boost mode operation of the digital PI controller. The boost mode operation achieves sub microsecond settling time, and reduces the settling time by 50% to 250 ns, undershoot/overshoot by 35% to 250 mV and 17% to 125 mV without compromising the system stability.Dissertation/ThesisDoctoral Dissertation Electrical Engineering 201

Emerging Power Electronics Technologies for Sustainable Energy Conversion

This Special Issue summarizes, in a single reference, timely emerging topics related to power electronics for sustainable energy conversion. Furthermore, at the same time, it provides the reader with valuable information related to open research opportunity niches

Emerging Power Electronics Technologies for Sustainable Energy Conversion

This Special Issue summarizes, in a single reference, timely emerging topics related to power electronics for sustainable energy conversion. Furthermore, at the same time, it provides the reader with valuable information related to open research opportunity niches