Electrical and Computer Engineering Commons^™

Novel Night And Day Control Of Pv Solar Farm As Statcom (Pv-Statcom) For Critical Induction Motor Stabilization And Fidvr Alleviation, Sibin Mohan

Electronic Thesis and Dissertation Repository

Induction motors are globally used in several critical operations such as petrochemicals, mining, process control, etc., where their shutdown during faults causes significant financial loss. System faults can also lead to Fault Induced Delayed Voltage Recovery (FIDVR) causing service disruptions. Dynamic reactive power compensators such as SVC and STATCOM are conventionally employed to mitigate these issues, however, these are very expensive.

PV solar plants are growing at unprecedented rate globally and are likely to be installed near such critical motors. This thesis presents several novel applications of a patented technology of utilizing PV solar plants, both during night and day, …

State Space Modeling Of Smart Pv Inverter As Statcom (Pv-Statcom) For Voltage Control In A Distribution System, Sridhar Bala Subramanian

Electronic Thesis and Dissertation Repository

The grid integration of photovoltaic (PV) systems in distribution networks is facing challenges such as transient changes in voltage due to fluctuations in generated real power and tripping of PV systems. Smart PV inverters with functions such as dynamic reactive current injection and low voltage ride through are available to mitigate these challenges. This thesis shows that a better stable performance can be obtained if these functions are implemented using the novel patent-pending technology of PV system as a dynamic reactive power compensator (PV-STATCOM). A linearized state space model of PV-STATCOM is developed to show the benefits of PV-STATCOM controls …

Smart Pv Inverter Control For Distribution Systems, Ehsan M. Siavashi

Electronic Thesis and Dissertation Repository

PV solar systems employ inverters to transform dc power from solar panels into ac power for injecting into the power grids. Inverters that perform multiple functions in addition to real power production are known as “smart inverters”.

This thesis presents a novel control of PV inverter as a dynamic reactive power compensator – STATCOM. This “smart PV inverter” control enables a PV solar inverter to operate in three modes – i) Full PV, ii) Partial STATCOM, and iii) Full STATCOM, depending upon system needs. The novel control is developed and demonstrated for the objectives of a) symmetrical voltage regulation, b) …

A Static Voltage Security Region For Centralized Wind Power Integration-Part I: Concept And Method, Tao Ding, Qinglai Guo, Rui Bo, Hongbin Sun, Boming Zhang

Electrical and Computer Engineering Faculty Research & Creative Works

When large wind farms are centrally integrated in a power grid, cascading tripping faults induced by voltage issues are becoming a great challenge. This paper therefore proposes a concept of static voltage security region to guarantee that the voltage will remain within operation limits under both base conditions and N-1 contingencies. For large wind farms, significant computational effort is required to calculate the exact boundary of the proposed security region. To reduce this computational burden and facilitate the overall analysis, the characteristics of the security region are first analyzed, and its boundary components are shown to be strictly convex. Approximate …

A Sensitivity Analysis Toolkit For The Simplification Of Mv Distribution Network Voltage Management, Fabian Tamp, Philip Ciufo

Dr Philip Ciufo

As distribution networks become increasingly variable and generation becomes increasingly decentralised, voltage standards are becoming more liable to violation. Accordingly, intelligent voltage management strategies are required to enable standards compliance without unduly increasing network maintenance or infrastructure costs. The relationship between network power and voltages, however, is complex, non-linear and interdependent, and thus is difficult to conceptualise and use for decision-making and control purposes.

This paper introduces a software toolkit that simplifies the development of voltage management strategies by the applica- tion of sensitivity analysis. Sensitivity analysis reduces complex network P – Q – |V | relationships to simple linear …

Novel Controls Of Photovoltaic (Pv) Solar Farms, Shah Arifur Rahman

Electronic Thesis and Dissertation Repository

Solar Farms are absolutely idle in the night and even during daytime operate below capacity in early mornings and late afternoons. Thus, the entire expensive asset of solar farms remains highly unutilized. This thesis presents novel technologies for utilization of PV solar farm inverter in nighttime for providing multiple benefits to power systems, as well as accomplishing the same objectives during the daytime from the inverter capacity left after production of real power. The new technology transforms a solar farm inverter functionally into a dynamic reactive power compensator known as STATCOM, and termed PV-STATCOM.

A novel coordinated control of PV-STATCOMs …

Swarm Intelligence And Evolutionary Approaches For Reactive Power And Voltage Control, Ganesh K. Venayagamoorthy, G. Krost, G. A. Bakare, Lisa L. Grant

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a comparison of swarm intelligence and evolutionary techniques based approaches for minimization of system losses and improvement of voltage profiles in a power network. Efficient distribution of reactive power in an electric network can be achieved by adjusting the excitation on generators, the on-load tap changer positions of transformers, and proper switching of discrete portions of inductors or capacitors. This is a mixed integer non-linear optimization problem where metaheuristics techniques have proven suitable for providing optimal solutions. Four algorithms explored in this paper include differential evolution (DE), particle swarm optimization (PSO), a hybrid combination of DE and …

An Improved Cascaded H-Bridge Multilevel Inverter Controlled By An Unbalanced Voltage Level Sigma-Delta Modulator, Jingsheng Liao, Mehdi Ferdowsi

Electrical and Computer Engineering Faculty Research & Creative Works

Multilevel inverters have been proven to be viable solutions for high-power automotive motor drive applications due to their high volt-ampere ratings. Cascaded H-bridge inverters are a promising breed of multilevel inverters which generally require several independent dc sources. Replacement of all but one of the dc sources with capacitors in cascaded H-bridge multilevel inverters, which leads to single-dc-source per-phase cascaded inverters, has recently gained popularity. However, very few efforts have been made to address the challenging problem of voltage regulation in the replacing capacitors. In this paper, applicability of a real-time voltage control technique named unbalanced voltage level sigma-delta modulation …

Discussion On Effective Control Of Inter-Area Oscillations By Upfcs, Mahyar Zarghami, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

The paper discusses an effective method for damping inter-area oscillations in a power network using UPFCs. This two stage method controls voltage magnitudes/angles of the two sides of the UPFC based on a linearized approach, which in turn will command modulation amplitudes and angles of the UPFC. The method is compared to a one stage linearized approach which directly commands modulation amplitudes and angles of the UPFC. Discussion on the feasibility of the method and its relation to the steady-state operation of the UPFC is also addressed.

A Unique Ultracapacitor Direct Integration Scheme In Multilevel Motor Drives For Large Vehicle Propulsion, Shuai Lu, Keith Corzine, Mehdi Ferdowsi

Electrical and Computer Engineering Faculty Research & Creative Works

This paper introduces a new set of methods to directly integrate ultracapacitor banks into cascaded multilevel inverters that are used for large vehicle propulsion. The idea is to replace the regular dc-link capacitors with ultracapacitors in order to combine the energy storage unit and motor drive. This approach eliminates the need for an interfacing dc-dc converter and considerably improves the efficiency of regenerative braking energy restoration in large vehicles using multilevel converters. Utilizing the proposed modulation control set, the two cascaded inverters can have their dc voltage levels maintained at any ratio (even a noninteger ratio) or dynamically varied over …

Swarm Intelligence For Transmission System Control, Ganesh K. Venayagamoorthy, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

Many areas related to power system transmission require solving one or more nonlinear optimization problems. While analytical methods might suffer from slow convergence and the curse of dimensionality, heuristics based swarm intelligence can be an efficient alternative. This paper highlights the application of swam intelligence techniques for solving some of the transmission system control problems.

Cancellation Predictive Control For Three-Phase Pwm Rectifiers Under Harmonic And Unbalanced Input Conditions, Peng Xiao, Keith Corzine, Ganesh K. Venayagamoorthy

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents an intuitive and simple-to-implement control scheme to improve the performance of three-phase boost-type PWM rectifiers under harmonic and unbalanced input conditions. Unlike most other control strategies, the proposed method does not need to extract either the harmonic or the negative-sequence components in the supply voltages and currents. A near-synchronous reference frame is used to determine the positive-sequence fundamental-frequency component in the input voltages. Utilizing only the extracted component, the DC-link voltage control and power factor control are implemented independently to determine the phase angle and magnitude of the PWM reference voltage. The commanded rectifier voltage adjustments are …

An Unique Ultracapacitor Direct Integration Scheme In Multilevel Motor Drives For Large Vehicle Propulsion, Shuai Lu, Keith Corzine, Mehdi Ferdowsi

Electrical and Computer Engineering Faculty Research & Creative Works

This paper introduces a new set of methods to directly integrate ultracapacitor banks into cascaded multilevel inverters used for large vehicle propulsion. The idea is to replace the regular dc-link capacitors with ultracapacitors in order to combine the energy storage unit and motor drive. This approach eliminates the need for an interfacing dc-dc converter and considerably improves the efficiency of regenerative braking energy restoration in electric and hybrid vehicles. Utilizing the proposed modulation control set, the two cascaded inverters can have their dc voltage levels maintained at any ratio (even a noninteger ratio) or dynamically varied over a wide range …

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.

Hysteresis And Delta Modulation Control Of Converters Using Sensorless Current Mode, Jonathan W. Kimball, Philip T. Krein, Yongxiang Chen

Electrical and Computer Engineering Faculty Research & Creative Works

Sensorless current mode (SCM) is a control formulation for dc-dc converters that results in voltage-source characteristics, excellent open-loop tracking, and near-ideal source rejection. Hysteresis and delta modulation are well-known, easy-to-construct large-signal methods for switched systems. Combining either large-signal method with SCM creates a controller that is simpler and more robust than a pulse-width modulation (PWM) based controller. The small-signal advantages of PWM-based SCM are retained and expanded to include converter response to large-signal disturbances. These approaches can be used with any converter topology over a broad range of operating conditions. In the present work, hysteresis and delta modulation SCM controllers …

Intelligent Optimal Control Of Excitation And Turbine Systems In Power Networks, Ganesh K. Venayagamoorthy, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

The increasing complexity of the modern power grid highlights the need for advanced modeling and control techniques for effective control of excitation and turbine systems. The crucial factors affecting the modern power systems today is voltage control and system stabilization during small and large disturbances. Simulation studies and real-time laboratory experimental studies carried out are described and the results show the successful control of the power system excitation and turbine systems with adaptive and optimal neurocontrol approaches. Performances of the neurocontrollers are compared with the conventional PI controllers for damping under different operating conditions for small and large disturbances.

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 …

Review Of Multiple Input Dc-Dc Converters For Electric And Hybrid Vehicles, Krishna P. Yalamanchili, Mehdi Ferdowsi

Electrical and Computer Engineering Faculty Research & Creative Works

Batteries, ultra capacitors, fuel cells, and solar arrays are widely used in electric and hybrid vehicles (EVs/HVs) as an electric power source or an energy storage unit. In the structure of the electric power system of modern EVs/HVs, more than one of these units may be employed to improve the performance and efficiency; hence utilization of a multi-input DC-DC converter is inevitable to obtain a regulated bus DC voltage. In this paper, a review of multiple input DC-DC power electronic converters (MI-PEC) devoted to combine the power flow from several on-board energy sources of an EV/HV is presented. Several multi-input …

Power Integrity Investigation Of Bga Footprints By Means Of The Segmentation Method, Giuseppe Selli, James L. Drewniak, Richard E. Dubroff, Jun Fan, James L. Knighten, Norman W. Smith, Dean Mccoy, Bruce Archambeault

Electrical and Computer Engineering Faculty Research & Creative Works

The engineering of the power delivery network is becoming a fundamental issue in the design of high speed digital systems on PCB's. In fact, providing the required power to the different IC's at the specified noisefree voltage levels allows a correct functioning of the overall PCB systems. More over, the ongoing trend of replacing active devices with peripherally located I/O and PWR/GND pins with areally located I/O and PWR/GND pins (BGA packaged) increases the complexity of the models, when power delivery issues need to be studied in a larger contest, such as the overall PCB's. The employment of the powerful, …

Pulse Regulation Control Technique For Flyback Converter, Mehdi Ferdowsi, Ali Emadi, Mark Telefus, Curtis Davis

Electrical and Computer Engineering Faculty Research & Creative Works

Pulse regulation, a fixed frequency control technique, is introduced and applied to flyback converter operating in discontinuous conduction mode (DCM). The control parameters are designed in a way that the converter operates as close as possible to the critical conduction mode. In contrast to the conventional pulsewidth modulation control scheme, the principal idea of pulse regulation is to achieve output voltage regulation using high and low-power pulses. Pulse regulation is simple, cost effective, and enjoys a fast dynamic response. The proposed technique is applicable to any converter operating in DCM. However, this work mainly focuses on flyback topology. In this …

Control Technique For Series Input-Parallel Output Converter Topologies, Jonathan W. Kimball, Joseph T. Mossoba, Philip T. Krein

Electrical and Computer Engineering Faculty Research & Creative Works

A series input-parallel output DC-DC converter topology inherently provides output current sharing among the phases, provided the input voltages are forced to share. With conventional output voltage feedback controls, input voltage sharing is unstable. Recent literature work proposes complicated feedback loops to provide stable voltage sharing, at the expense of dynamic performance. In the current work, a simple controller based on the sensorless current mode approach (SCM) stabilizes voltage sharing without compromising system performance. The SCM controllers reject source disturbances, and allow the output voltage to be tightly regulated by additional feedback control. With SCM control in place, a #super-matched# …

Analysis And Design Of Switched Capacitor Converters, Jonathan W. Kimball, Philip T. Krein

Electrical and Computer Engineering Faculty Research & Creative Works

Switched capacitor converters have become more common in recent years. Crucial to understanding the maximum power throughput and efficiency is a model of the converter's equivalent resistance. A new form for equivalent resistance is derived and discussed in a design context. Quasi-resonant operation is also explored and compared to non-resonant operation. Several capacitor technologies are evaluated and compared.

Pulse Regulation Control Technique For Integrated High-Quality Rectifier-Regulators, Mehdi Ferdowsi, Ali Emadi

Electrical and Computer Engineering Faculty Research & Creative Works

The pulse regulation control scheme is presented and applied to the boost integrated flyback rectifier/energy storage dc/dc (BIFRED) converter as the most popular member of the integrated high-quality rectifier-regulators (IHQRR). In contrast to the conventional control techniques, the principal idea of pulse regulation is to regulate the output voltage using a series of high- and low-power pulses generated by the current of the input inductor, which is operating in discontinuous conduction mode (DCM). Analysis of the BIFRED converter operating in DCM is presented. Fundamentals of pulse regulation as well as its stability analysis and the estimation of the output voltage …

Reactive Power And Voltage Control Of The Nigerian Grid System Using Micro-Genetic Algorithm, Ganesh K. Venayagamoorthy, G. A. Bakare, U. O. Aliyu

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a micro-genetic based approach to the optimization of reactive power and voltage profiles improvement and real power loss minimization is presented. The reactive power control devices such as generators, tap positions of on-load tap changer of transformers, shunt reactors are used to correct voltage limits violations while simultaneously reducing the system real power losses. Genetic algorithms (GAs) are well-known global search techniques anchored on the mechanisms of natural selection and genetics. Because of the time intensive nature of the conventional GA, the micro-GA is proposed as a more time efficient alternative. The feasibility and effectiveness of the …

Adaptive Critic Designs For Optimal Control Of Power Systems, Ganesh K. Venayagamoorthy, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

The increasing complexity of the modern power grid highlights the need for advanced modeling and control techniques for effective control of excitation, turbine and flexible AC transmission systems (FACTS). The crucial factors affecting the modern power systems today is voltage and load flow control. Simulation studies in the PSCAD/EMTDC environment and realtime laboratory experimental studies carried out are described and the results show the successful control of the power system elements and the entire power system with adaptive and optimal neurocontrol schemes. Performances of the neurocontrollers are compared with the conventional PI controllers for damping under different operating conditions for …

Suitability Of Pulse Train Control Technique For Bifred Converter, Mehdi Ferdowsi, Ali Emadi, Mark Telefus, Anatoly Shteynberg

Electrical and Computer Engineering Faculty Research & Creative Works

Pulse Train^TM control scheme is presented and applied to a boost integrated flyback rectifier/energy storage dc-dc (BIFRED) converter operating in discontinuous conduction mode (DCM), which avoids the light-load high-voltage stress problem. In contrast to the conventional control techniques, the principal idea of Pulse Train technique is to regulate the output voltage using a series of high and low energy pulses generated by the current of the inductor. The applicability of the proposed technique to both the input and magnetizing inductances of BIFRED converter is investigated. Analysis of BIFRED converter operating in DCM as well as the output voltage ripple …

Low-Input-Voltage, Low-Power Boost Converter Design Issues, Jonathan W. Kimball, Theresa L. Flowers, Patrick L. Chapman

Electrical and Computer Engineering Faculty Research & Creative Works

Issues associated with boost converter design and performance are investigated when a low input voltage is used. Low-input-voltage sources include single fuel cells, single solar cells, and thermoelectric devices. The primary context is interfacing single micro fuel cells to portable electronic loads, such as mobile phones. Efficiency and circuit startup are the two most difficult issues for a low-cost design. It is shown in theory and experiment that the boost converter has a voltage collapse point. A simple startup technique is proposed that is appropriate for some applications.

A Method Of Including Switching Loss In Electro-Thermal Simulations, Jonathan W. Kimball

Electrical and Computer Engineering Faculty Research & Creative Works

Often, power electronics systems are simulated with ideal switching elements, perhaps augmented with conduction loss models. A behavioral model is proposed that also includes switching loss and is independent of switching frequency. Therefore, it is suitable for variable frequency control methods, including hysteresis, delta modulation, and random PWM. Models have been realized in Dymola using voltage-controlled voltage sources, current sources, logic, and additional ideal switches. Thermal ports are included to facilitate electro-thermal simulation. A method for parameter extraction is demonstrated using experimental data from standard PWM.

Pulse Regulation Control Technique For Bifred Converter, Mehdi Ferdowsi, Ali Emadi, Mark Telefus, Curtis Davis

Electrical and Computer Engineering Faculty Research & Creative Works

Pulse Regulation control scheme is presented and applied to BIFRED converter operating in discontinuous conduction mode (DCM). In contrast to the conventional control techniques, the principal idea of Pulse Regulation is to regulate the output voltage using a series of high and low power pulses generated by the current of the input inductor. In this paper, analysis of BIFRED converter operating in DCM is presented. The basic idea of Pulse Regulation as well as the estimation of the output voltage ripple is introduced. Experimental results on a prototype converter are also demonstrated.

Pulse Train Control Technique For Flyback Converter, Mark Telefus, Anatoly Shteynberg, Mehdi Ferdowsi, Ali Emadi

Electrical and Computer Engineering Faculty Research & Creative Works

Pulse Train^TM control technique is introduced and applied to flyback converter operating in discontinuous conduction mode (DCM). In contrast to the conventional pulse width modulation (PWM) control scheme, the principal idea of Pulse Train is to achieve output voltage regulation using high and low power pulses. The proposed technique is applicable to any converter operating in DCM. However, this work mainly focuses on flyback topology. In this paper, the main mathematical concept of the new control algorithm is introduced and simulations as well as experimental results are presented.