Digital Commons Network^™

Chaotic Behavior In High-Gain Interleaved Dc-Dc Converters, Ahmad Alzahrani, Pourya Shamsi, Mehdi Ferdowsi, Cihan H. Dagli

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, chaotic behavior in high gain dc-dc converters with current mode control is explored. The dc-dc converters exhibit some chaotic behavior because they contain switches. Moreover, in power electronics (circuits with more passive elements), the dynamics become rich in nonlinearity and become difficult to capture with linear analytical models. Therefore, studying modeling approaches and analysis methods is required. Most of the high-gain dc-dc boost converters cannot be controlled with only voltage mode control due to the presence of right half plane zero that narrows down the stability region. Therefore, the need of current mode control is necessary to …

Advanced Control Of Grid-Connected Multilevel Power Electronic Rectifiers, Sangin Lee

Doctoral Dissertations

"Multilevel power electronic converters have been gaining attention due to their ability to supply high amounts of power and to handle high voltage levels. In this dissertation, grid connected AC-DC rectifier application is investigated with different topologies and control scheme.

At first, neutral point clamped (NPC) rectifier is employed to transfer power from the grid to the load. The NPC rectifier has two capacitors in order to build multilevel output voltage. However, it causes voltage unbalancing problem. Therefore, the new method has been proposed to regulate each capacitor voltage at the same voltage level. Experimental results show that it is …

Comparative Study Of Three Types Of Inverters Based On The Output Total Harmonic Distortion, Paterrson Thomas

Masters Theses

"In this thesis, three cases of power electronic inverters are taken into consideration to analyze their performance in terms of total harmonic distortion in their output voltage and output current. Firstly, a single H-bridge inverter is simulated. Staircase switching technique is used to generate the gating pulses for the switches. Only one switch is made to toggle for every half cycle. The fundamental harmonic component of the desired output voltage is considered to be 120 V. Secondly, the same topology is used with a Bipolar PWM gating technique. The switching frequency of the carrier wave is 33*60 Hz. Thirdly, a …

Addressing Control And Capacitor Voltage Regulation Challenges In Multilevel Power Electronic Converters, Hossein Sepahvand

Doctoral Dissertations

Multilevel power electronic converters are the current industry solutions for applications that demand medium voltage, reasonable efficiency, and high power quality. The proper operation of these types of power converters requires special control, modulation methods, and capacitor voltage regulation techniques. Both developing capacitor voltage regulation methods and addressing their associated issues with such fall within the primary focus of this dissertation. In this dissertation an investigation was conducted on the capacitor voltage regulation constraints in cascaded H-bridge multilevel converters with a staircase output voltage waveform. In the proposed method, the harmonic elimination technique is used to determine the switching angles. …

Reducing Common-Mode Voltage In Three-Phase Sine-Triangle Pwm With Interleaved Carriers, Jonathan W. Kimball, Maciej Jan Zawodniok

Electrical and Computer Engineering Faculty Research & Creative Works

Interleaving PWM waveforms is a proven method to reduce ripple in dc-dc converters. The present work explores interleaving for three-phase motor drives. Fourier analysis shows that interleaving the carriers in conventional uniform PWM significantly reduces the common-mode voltage. New DSP hardware supports interleaving directly with changes to just two registers at setup time, so no additional computation time is needed during operation. The common-mode voltage reduction ranges from 36% at full modulation to 67% when idling with zero modulation. Third harmonic injection slightly reduces the advantage (to 26% at full modulation). However, the maximum RMS common-mode voltage is still less …

Current Sensing For Automotive Electronics -- A Survey, Asha Patel, Mehdi Ferdowsi

Electrical and Computer Engineering Faculty Research & Creative Works

Current sensing is widely used in power electronic applications such as dc-dc power converters and adjustable-speed motor drives. Such power converters are the basic building blocks of drivetrains in electric, hybrid, and plug-in hybrid electric vehicles. The performance and control of such vehicles depend on the accuracy, bandwidth, and efficiency of its sensors. Various current-sensing techniques based on different physical effects such as Faraday's induction law, Ohm's law, Lorentz force law, the magnetoresistance effect, and the magnetic saturation effect are described in this paper. Each technique is reviewed and examined. The current measurement methods are compared and analyzed based on …

Reliability Analysis For The Advanced Electric Power Grid: From Cyber Control And Communication To Physical Manifestations Of Failure, Ayman Z. Faza, Sahra Sedigh, Bruce M. Mcmillin

Electrical and Computer Engineering Faculty Research & Creative Works

The advanced electric power grid is a cyber-physical system comprised of physical components, such as transmission lines and generators, and a network of embedded systems deployed for their cyber control. The objective of this paper is to qualitatively and quantitatively analyze the reliability of this cyber-physical system. The original contribution of the approach lies in the scope of failures analyzed, which crosses the cyber-physical boundary by investigating physical manifestations of failures in cyber control. As an example of power electronics deployed to enhance and control the operation of the grid, we study Flexible AC Transmission System (FACTS) devices, which are …

Power Sharing In A Double-Input Buckboost Converter Using Offset Time Control, Deepak Somayajula, Mehdi Ferdowsi

Electrical and Computer Engineering Faculty Research & Creative Works

Multi-input power electronic converters have been gaining popularity in applications such as renewable energy sources and hybrid electric vehicles due to their reduced component count. In this paper, a new control method is introduced and successfully applied to a double-input buckboost converter to adjust the power supplied by each one of the sources. The control scheme is based on controlling the offset time between the switching commands while switching frequency is kept constant. Theoretically, it is proved that the offset time between the switch commands has a direct impact on the amount of current drawn from each source. The proposed …

Small-Signal Impedance Measurement Of Power-Electronics-Based Ac Power Systems Using Line-To-Line Current Injection, Jing Huang, Keith Corzine, M. Belkhayat

Electrical and Computer Engineering Faculty Research & Creative Works

Naval ships as well as aerospace power systems are incorporating a greater degree of power electronic switching sources and loads. Although these components provide exceptional performance, they are prone to instability due to their high efficiency and constant power characteristics that can exhibit negative impedance nature at certain frequencies. When designing these systems, integrators must consider the impedance versus frequency at an interface (which designates source and load). Stability criteria have been developed in terms of source and load impedances for both dc and ac systems, and it is often helpful to have techniques for impedance measurement. For dc systems, …

Online Optimal Neuro-Fuzzy Flux Controller For Dtc Based Induction Motor Drives, N. Sadati, S. Kaboli, H. Adeli, E. Hajipour, Mehdi Ferdowsi

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper a fast flux search controller based on the Neuro-fuzzy systems is proposed to achieve the best efficiency of a direct torque controlled induction motor at light load. In this method the reference flux value is determined through a minimization algorithm with stator current as objective function. This paper discusses and demonstrates the application of Neurofuzzy filtering to stator current estimation. Simulation and experimental results are presented to show the fast response of proposed controller.

Cavities' Identification Algorithm For Power Integrity Analysis Of Complex Boards, S. Cicerone, Antonio Orlandi, Bruce Archambeault, Samuel R. Connor, Jun Fan, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

The analysis and the design of the Power Delivery Network (PDN) is crucial in the real world of high-speed and high-performance on-board systems. In this context, the Cavity Model (where facing portions of power bus are considered electromagnetic resonant cavities) can be used to study the generation and propagation of noise. Given a real-world board's layout, one of the primary requirements for the application of this technique is the geometrical identification of all the cavities and their connectivity. This paper is focused on the fully automatic generation of this geometrical dataset as part of an integrated tool for the analysis …

Seven-Level Shunt Active Power Filter For High-Power Drive Systems, Peng Xiao, Ganesh K. Venayagamoorthy, Keith Corzine

Electrical and Computer Engineering Faculty Research & Creative Works

In high-power adjustable-speed motor drives, such as those used in electric ship propulsion systems, active filters provide a viable solution to mitigating harmonic related issues caused by diode or thyristor rectifier front-ends. To handle the large compensation currents and provide better thermal management, two or more paralleled semiconductor switching devices can be used. In this paper, a novel topology is proposed where two active filter inverters are connected with tapped reactors to share the compensation currents. The proposed active filter topology can also produce seven voltage levels, which significantly reduces the switching current ripple and the size of passive components. …

Self-Tuned Projected Cross Point -- An Improved Current-Mode Control Technique, Kai-Tak Wan, Mehdi Ferdowsi

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Self-tuned projected cross point control for power electronic converters is introduced. Projected cross point control (PCPC) combines the advantages of both analog and digital current-mode control techniques. Despite several advantages, accuracy of the PCPC method depends on the power stage inductor value. However, ferromagnetic characteristics of the inductor core material make the inductor measurement inaccurate. Furthermore, the inductor value is subject to change due to temperature variations or other environmental effects. To overcome the dependence of the PCPC method on the inductor value, self- tuned PCPC approach is introduced in this paper. Unlike the conventional PCPC scheme, self-tuned PCPC method …

Plug-In Electric Drive Vehicles: Experiences In Research And Education, Mehdi Ferdowsi

Electrical and Computer Engineering Faculty Research & Creative Works

This paper briefly describes the research and educational activities related to a current NSF CAREER grant titled "Vehicle Fleet as a Distributed Energy Storage System for the Power Grid". The PI, Dr. Ferdowsi, is an assistant professor at the Electrical and Computer Engineering Department of the Missouri University of Science and Technology (MST).

Synthesis Of Double-Input Dc-Dc Converters Using A Single-Pole Triple-Throw Switch As A Building Block, Karteek Gummi, Mehdi Ferdowsi

Electrical and Computer Engineering Faculty Research & Creative Works

Hybridizing power electronic systems using an energy storage unit has gained popularity in transportation and power system applications. This task has traditionally been performed by using several independent power electronic converters. Multi-input converters, due to their reduced part count and improved efficiency, seem to be an advantageous option to replace the conventional converters. A few multi-input converter topologies have been reported in the literature; however, there is not a systematic approach to derive them. Furthermore, all possible topologies are not completely explored and it is difficult to derive new converters from the existing topologies. Hence, in this paper, a systematic …

A New Control Method For Single-Dc-Source Cascaded H-Bridge Multilevel Converters Using Phase-Shift Modulation, Jingsheng Liao, Keith Corzine, Mehdi Ferdowsi

Electrical and Computer Engineering Faculty Research & Creative Works

Multilevel converters have gained popularity in high-power applications due to their low switch voltage stress and modularity. Cascaded H-bridge converters are a promising breed of multilevel converters, which generally require several independent dc sources. Using phase-shift modulation, a new control method for cascaded H-bridge multilevel converters with only one independent dc source per phase is presented in this paper. Unlike the conventional approaches, the proposed method has a wide voltage regulation range over the capacitors replacing the dc sources in the H-bridge converter cells.

A Current-Sensorless Digital Controller For Active Power Factor Correction Control Based On Kalman Filters, Jonathan W. Kimball, Philip T. Krein

Electrical and Computer Engineering Faculty Research & Creative Works

For low-power AC-DC converters, power factor correction (PFC) can be accomplished simply with certain converters operating in discontinuous conduction mode (DCM). At higher power levels, DCM results in higher losses, so most PFC converters use current feedback to actively track the correct current waveshape. This work presents a way to provide PFC control without the current sensor, by replacing the sensor with a Kalman filter, which is essentially a stochastic observer. Experimental results verify its high power factor and low total harmonic distortion (THD).

Plug-In Hybrid Vehicles -- A Vision For The Future, Mehdi Ferdowsi

Electrical and Computer Engineering Faculty Research & Creative Works

One of the unique advantages of plug-in hybrid vehicles is their capability to integrate the transportation and electric power generation sectors in order to improve the efficiency, fuel economy, and reliability of both systems. This goal is performed via integration of the onboard energy storage units of plug-in vehicles with the power grid by power electronic converters and communication systems. Employing energy storage systems improves the efficiency and reliability of the electric power generation, transmission, and distribution. Similarly, combining an energy storage system with the power train of a conventional vehicle results in a hybrid vehicle with higher fuel efficiency. …

Early Time Charge Replenishment Of The Power Delivery Network In Multi-Layer Pcbs, Giuseppe Selli, Matteo Cocchini, James L. Knighten, Bruce Archambeault, Jun Fan, Samuel R. Connor, Antonio Orlandi, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

The investigation of decoupling issues has been extensively treated in the literature in both the frequency and the time domain [1-9]. The two domains describe from different perspectives the same physical phenomenon, being related by a Fourier transform. In this article, well known decoupling issues usually addressed in the frequency domain [1,2] are discussed in the time domain. Moreover, some modeling issues related to the cavity model approach are discussed and, in particular, the circuit extraction feature associated with this methodology is utilized throughout the article to carry out the time domain simulations within a SPICE based-tool. The depletion of …

Digital Ripple Correlation Control For Photovoltaic Applications, Jonathan W. Kimball, Philip T. Krein

Electrical and Computer Engineering Faculty Research & Creative Works

Ripple correlation control (RCC) is a fast, robust online optimization technique. RCC is particularly suited for switching power converters, where the inherent ripple provides information about the system operating point. The present work examines a digital formulation that has reduced power consumption and greater robustness. A maximum power point tracker for a photovoltaic panel demonstrates greater than 99% tracking accuracy and fast convergence.

A Novel Impedance Measurement Technique For Power Electronic Systems, Peng Xiao, Ganesh K. Venayagamoorthy, Keith Corzine

Electrical and Computer Engineering Faculty Research & Creative Works

When designing and building power systems that contain power electronic switching sources and loads, system integrators must consider the frequency-dependent impedance characteristics at an interface to ensure system stability. Stability criteria have been developed in terms of source and load impedance for both dc and ac systems and it is often necessary to measure system impedance through experiments. Traditional injection-based impedance measurement techniques require multiple online tests which lead to many disadvantages. The impedance identification method proposed in this paper greatly reduces online test time by modeling the system with recurrent neural networks. The recurrent networks are trained with measured …

Singular Perturbation Theory For Dc-Dc Converters And Application To Pfc Converters, Jonathan W. Kimball, Philip T. Krein

Electrical and Computer Engineering Faculty Research & Creative Works

Many control schemes for dc-dc converters begin with the assertion that inductor currents are "fast" states and capacitor voltages are "slow" states. This assertion must be true for power factor correction (PFC) converters to allow independent control of current and voltage. In the present work, singular perturbation theory is applied to boost converters to provide rigorous justification of the time scale separation. Krylov-Bogoliubov-Mitropolsky (KBM) averaging is used to include switching ripple effects. A relationship between inductance, capacitance, load resistance, and loss resistances derives from an analysis of an approximate model. Similar results hold for buck and buck-boost converters. An experimental …

Impedance Identification Of Integrated Power System Components Using Recurrent Neural Networks., Peng Xiao, Ganesh K. Venayagamoorthy, Keith Corzine

Electrical and Computer Engineering Faculty Research & Creative Works

Impedance characteristics of shipboard power systems provide important information for studies on system stability and integration. Existing injection based impedance measurement techniques require multiple tests on the system to obtain characteristics over wide frequency ranges. In this paper, recurrent neural networks (RNNs) are used to model the small signal dynamics of power electronic systems based on a single test in which randomized signals are injected into the system. The trained RNN is then used to extract the small-signal impedances/admittances of the system. A number of tests have been carried out in simulation to verify the effectiveness of the proposed method.

Combined Training Of Recurrent Neural Networks With Particle Swarm Optimization And Backpropagation Algorithms For Impedance Identification, Peng Xiao, Ganesh K. Venayagamoorthy, Keith Corzine

Electrical and Computer Engineering Faculty Research & Creative Works

A recurrent neural network (RNN) trained with a combination of particle swarm optimization (PSO) and backpropagation (BP) algorithms is proposed in this paper. The network is used as a dynamic system modeling tool to identify the frequency-dependent impedances of power electronic systems such as rectifiers, inverters, and DC-DC converters. As a category of supervised learning methods, the various backpropagation training algorithms developed for recurrent neural networks use gradient descent information to guide their search for optimal weights solutions that minimize the output errors. While they prove to be very robust and effective in training many types of network structures, they …

Ac Impedance Measurement By Line-To-Line Injected Current, Keith Corzine, Jing Huang

Electrical and Computer Engineering Faculty Research & Creative Works

Naval ship as well as aerospace power systems are incorporating a greater degree of power electronic switching sources and loads. Although these components provide exceptional performance, they are prone to instability due to their high efficiency and constant power characteristics which lead to a negative impedance nature. When designing these systems, system integrators must consider the impedance versus frequency at an interface (which designates source and load). Stability criteria have been developed in terms of source and load impedance for both DC and AC systems and it is often helpful to have techniques for impedance measurement. For DC systems, the …

Dynamic Maximum Power Point Tracking Of Photovoltaic Arrays Using Ripple Correlation Control, Trishan Esram, Jonathan W. Kimball, Philip T. Krein, Patrick L. Chapman, Pallab Midya

Electrical and Computer Engineering Faculty Research & Creative Works

A dynamically rapid method used for tracking the maximum power point of photovoltaic arrays, known as ripple correlation control, is presented and verified against experiment. The technique takes advantage of the signal ripple, which is automatically present in power converters. The ripple is interpreted as a perturbation from which a gradient ascent optimization can be realized. The technique converges asymptotically at maximum speed to the maximum power point without the benefit of any array parameters or measurements. The technique has simple circuit implementations.

An Efficient Discontinuous-Mode Model Of A Switch Pole, Jonathan W. Kimball

Electrical and Computer Engineering Faculty Research & Creative Works

Simulating switching power supplies presents many challenges. A variety of switch pole models is available, from the physics-based to the behavioral. The present work develops and demonstrates a behavioral model that works well in discontinuous mode. The new model eliminates the extremely fast time constants normally associated with switches in a high impedance state. Simulation time is improved and fixed-time-step algorithms are now stable with reasonable step size.

An Estimative Current Mode Controller For Dc-Dc Converters Operating In Continuous Conduction Mode, Mehdi Ferdowsi

Electrical and Computer Engineering Faculty Research & Creative Works

A new digital average-current-mode controller for converters operating in continuous conduction mode is introduced. The principal idea of the proposed control scheme is to estimate the required value of the duty ratio based on the dynamic of the converter using the measured samples of current and voltage signals. The proposed control scheme is stable for any value of the duty ratio without employing an external ramp. Furthermore, it is robust, accurate, and has a fast dynamic response.

Circuit Models For Power Bus Structures On Printed Circuit Boards Using A Hybrid Fem-Spice Method, Todd H. Hubing, Chunlei Guo

Electrical and Computer Engineering Faculty Research & Creative Works

Power bus structures consisting of two parallel conducting planes are widely used on high-speed printed circuit boards. In this paper, a full-wave finite-element method (FEM) method is used to analyze power bus structures, and the resulting matrix equations are converted to equivalent circuits that can be analyzed using SPICE programs. Using this method of combining FEM and SPICE, power bus structures of arbitrary shape can be modeled efficiently both in the time-domain and frequency-domain, along with the circuit components connected to the bus. Dielectric loss and losses due to the finite resistance of the power planes can also be modeled. …

A Comparison Of Diode-Clamped And Cascaded Multilevel Converters For A Statcom With Energy Storage, Ying Cheng, Chang Qian, Mariesa Crow, Steven Pekarek, Stan Atcitty

Electrical and Computer Engineering Faculty Research & Creative Works

The progression of distributed generation within a bulk power system will lead to the need for greater control of transmission-line power flows. Static synchronous compensators (STATCOMs) provide a power-electronics-based means of embedded control of transmission-line voltage and power flows. The integration of energy storage with a STATCOM can extend traditional STATCOM capabilities to four-quadrant power flow control and transient stability improvement. This paper discusses energy storage systems (ESSs) integrated with conventional and multilevel bidirectional power converters for a hybrid STATCOM/ESS. Conventional, diode-clamped, and cascaded multilevel converter-based STATCOM/ESSs are developed, and their performances for a variety of power system applications are …