Achieving a PhD is the culmination of relentless dedication, a testament to intellectual growth and a step towards shaping the future. Congratulations Dr. Franco Degioanni!

Franco defended his PhD thesis titled “Fast Dynamic Transient Solutions for Three-Phase PWM Converters”, at the University of British Columbia, giving a grand finale to this key stage of his career.

His achievements include:

• 3 IEEE transactions journals in IEEE Transactions on Power Electronics (TPEL) and IEEE Transactions on Industrial Electronics (TIE)

• IEEE journals in IEEE Transactions on Power Electronics (TPEL) and IEEE Journal of Emerging and Selected Topics in Power Electronics as second author (JESTPE)

• 5 conference papers in Applied Power Electronics Conference and Exposition (APEC) and IEEE Energy Conversion Congress & Expo (ECCE)

• Industrial collaborations with Alpha Technologies on control of resonant converters

• 6-month internship at Tesla as Power Electronics and Firmware Engineering intern

• Contributions to IEEE community as the Vice Chair of IEEE Power Electronics Society (PELS) of Vancouver Section

• Leading multitude of lab roles including but not limited to: 5 years leading lab recruitment efforts as a member of HR team, 3 years of firmware development and high-level planning.

His awards and fellowships include:

• Best paper presentation award APEC 2021

• Four-year doctoral fellowship (awarded for UBC’s best PhD students)

• Faculty of Applied Science Graduate Award (awarded for graduate and postdoctoral students of UBC)

Franco’s valuable contributions have greatly contributed to the success of #martinordonezlab for which we are grateful. We extend our best wished for success in all his forthcoming ventures.

We would further like to express our gratitude to PhD examination chair Antony Hodgson; Sup. Cmte.: Martin Ordonez and Emanuel Serban; Emxaminer cmte.: Alireza Nojeh and Ryozo Nagamune; and Ext. examiner: Mehdi Narimani, for their participation.

Abstract for Franco Degioanni’s PhD Thesis:
Title: Fast Dynamic Transient Solutions for Three-Phase PWM Converters

Abstract: The ever-growing global energy demand accentuates the importance of integrating renewable energy sources into the grid. Beyond fulfilling escalating energy needs, this integration holds the potential to reduce the dependency on fossil fuels. In this context, power electronics systems assume a key role in the efficient utilization of renewable energy. Particularly, the three-phase pulse-width-modulated (PWM) converter serves as the bridge that facilitates the seamless interaction between the grid, distributed re-sources, and loads. However, as power electronics systems increase in complexity, challenges emerge in terms of modeling, control design, and implementation. Overcoming these challenges necessitates ad-vancements in control design to enhance dynamic performance and optimize the efficiency of integrating renewable energy.

This thesis aims to improve the understanding of the dynamic characteristics of three-phase PWM converters, and to develop novel tools for modeling, analyzing and improving their dynamic performance in grid-connected applications. By employing concepts such as normalization, state plane representation, and geometric analysis, a comprehensive large-signal model for three-phase converter is developed. This model offers an intuitive graphical interpretation of the system’s dynamic behavior by illustrating its evolution in the state plane. Initially, the application of this framework facilitates the identification and characterization of the theoretical limits of dynamic performance. Consequently, it serves as a point of reference for control design engineers to conduct an objective assessment of the converter’s dynamic performance. Furthermore, the introduced analysis enables the development of high-performance control methods, even for challenging scenarios such as controlling active loads and bidirectional operation with wide operating range requirements. These control techniques ensure consistent large-signal behavior, fast transient responses, and low implementation requirements. In this manner, the thesis contributes to advancing power electronics modeling and control through the enhancement of the dynamic performance of three-phase converters.

A successful PhD graduation is the result of dedication, determination and a relentless pursuit of knowledge. Congratulations Dr. Jun (Jeremy) Min!

Jeremy defended his PhD thesis titled “Bidirectional Resonant Chargers for E-Mobility”, at the University of British Columbia.

Jeremy’s achievements include but are not limited to:

• 3 journal papers published in IEEE Transactions on Power Electronics, 3 conference papers published in IEEE Energy Conversion Congress and Exposition (ECCE) and 1 conference paper published in IEEE Applied Power Electronics Conference and Exposition (APEC)

• 3 years of industrial collaborations with Delta-Q technologies and Enersys as a research scholar, researching and developing new technologies

• 2 years leading lab recruitment efforts as a member of the HR team

• Contributions to IEEE community as the IEEE Vice Chair of Power Electronics Society (PELS) of Vancouver Section

His awards and fellowships include:

• Four-year doctoral fellowship (awarded for UBC’s best PhD students)

• Graduate Student Initiative Award (awarded for graduate and postdoctoral students of UBC)

We are grateful to have had Jeremy contributing to the success of #martinordonezlab all of these years and wish him the best of luck in all his future endeavors.

We would further like to express our gratitude to PhD examination chair Steve Cockcroft; Sup. cmte.: Martin Ordonez, Juri Jatskevich and Navid Shafiei; Examiner cmte.: Shahriar Mirabbasi, and Curtis Berlinguette; and Ext. examiner: Mehrdad Kazerani, for their participation.

Abstract for Jun(Jeremy) Min’s PhD thesis

Title: “Bidirectional Resonant Chargers for E-Mobility”

Abstract: This thesis investigates the development of efficient bidirectional chargers, an integral component for advancing e-mobility. Electric vehicles (EVs), energized by renewable sources, could mitigate the power grid instability by returning stored energy when renewables are less available. Battery voltage in EVs, however, can vary widely based on the EV’s application and its battery’s State of Charge (SoC). This necessitates employing various bidirectional charger techniques that can handle a broad range of EV battery voltages when connected to the renewable energy grid.

Three innovative techniques are proposed. Firstly, this work introduces the Asymmetric Parameters Methodology (APM), a technique that enables the design of asymmetric resonant tanks in bidirectional resonant CLLC DC/DC stages. APM, optimized through a statistical Design of Experiments (DoE) approach, results in a narrower bidirectional switching frequency range, reduced component current stress, and smaller transformer size.

The second technique is a unified bidirectional resonant frequency tracking method for the CLLC DC/DC stage of battery chargers, which decreases bidirectional resonance tracking costs and complexity while enhancing efficiency under parameter deviations. It is based on the discovery of two interesting features of the CLLC converters: one, the maximum efficiency for charging and discharging modes occurs at a variable but bidirectionally identical resonant frequency. Two, the voltages at both ends of the resonant tank remain in phase at this frequency for bidirectional operations.

This thesis introduces a third technique: a cascaded half-bridge-based multi-level multi-port bridgeless PFC rectifier for the AC/DC stage of chargers. Suitable for low-voltage battery charging, this technique divides high-voltage DC bus voltage into multiple low-voltage ports for the following CLLC DC/DC converter stage. This allows the transformer ratio of the DC/DC converter stage to be designed close to 1. Compared to cascaded full-bridge multi-level PFC, this approach cuts the number of switches per cell by half, while maintaining the same output ports. It also reduces input current ripple due to the reduction in volt-seconds on the boost inductor.

A strong dedication and an unwavering determination are what it takes to become a PhD graduate.
Congratulations Dr. Jhih-Da(Daniel) Hsu!

Last week, Daniel successfully defended his PhD thesis titled “High-Performance Resonant Converters for Battery Chargers: Efficiency and Dynamics Improvement”, at The University of British Columbia.

Daniel’s achievements include:

• 3 journal papers published on IEEE transactions on power electronics and IEEE journal of emerging and selected topics in power electronics

• 5 years industrial collaborations with Delta-Q technologies developing power converters for EV chargers

• 4 years leading lab recruitment efforts as a member of the HR team

• 4 years managing undergraduate coop/capstone projects

• Contributions to NSERC collaborative research and development grant proposal writing

His awards and fellowships:

•  Four-year doctoral fellowship (awarded for UBC’s best PhD students)

• President's Academic Excellence Initiative PhD Award (awarded to PhD students with significant contributions to research)

His immeasurable contributions to #martinordonezlab during all these years are greatly appreciated and we wish him the very best in all his future endeavors. 

We would also like to extend our thanks to PhD examination chair Michael Fryzuk; Sup. cmte.: Martin Ordonez, and Wilson Eberle; Examiner cmte.: Shahriar Mirabbasi, and Ryozo Nagamune; and Ext. examiner: Peter Lehn, for their participation.

Abstract for Jhih-Da(Daniel) Hsu’s PhD thesis
Title: “High-Performance Resonant Converters for Battery Chargers: Efficiency and Dynamics Improvement”

Abstract: As the requirement for clean energy grows, the demand for high-performance power conversion for energy storage and battery charging applications has been soaring. Resonant converters, in particular, LLC or CLLC converters, have been broadly adopted for high-power battery chargers. The purpose of this work is to further improve the performance of the resonant converters from both the efficiency and dynamics aspects. In terms of improving the efficiency, this work focuses on reducing the conduction losses of the output rectifiers using Synchronous Rectification (SR). Conventional SR controllers detect the drain-source voltage during the SR turn-on phase (vds.on) as the control input. However, vds.on is low-magnitude and sensitive to the voltage noise caused by parasitic elements. The distorted vds.on causes SR mis-triggering, undermining the efficiency. With the focus on mainstream LLC resonant converters, this work first introduces a new SR driving strategy based on the resonant capacitor voltage (RCV). Next, a simplified SR method is proposed; it is based on the Volt-Second Product (VSP) of SR drain-source blocking voltage and rectifier current conduction time. Both methods employ large-magnitude voltages, which are insensitive to the noise generated by parasitic components, reducing SR on-time error. The proposed SR methods are compared with the conventional vds.on based SR to demonstrate the efficiency improvement. Regarding the dynamics aspect, this work focuses on improving the small-signal dynamic model for charge-controlled resonant converters. Charge mode control has been applied to resonant converters to improve the system dynamics, and yet the conventional small-signal model emphasizes only the low-frequency region, which is not suitable for high-bandwidth designs. This work establishes the small-signal modeling methodology based on Extended Describing Functions (EDF) and phasor analysis, which successfully predicts the system frequency response across low- to high-frequency regions, enabling high-bandwidth designs. As the proposed noise-tolerant SR methods improve the efficiency performance, the enhanced small-signal model assists to achieve wide loop bandwidth, improving the dynamic performance. This work provides solutions and insights to the design of high-performance resonant battery chargers.

Perseverance and dedication are secrets to success: Congratulations to Dr. Sayed Abbas Arshadi for defending his PhD thesis successfully!

Last week Abbas defended his thesis on “Three-Phase DC-DC Resonant Converters for High-Power Battery Charging Applications”, achieving this significant milestone in his career. 

Abbas’ achievements include but are not limited to the following:

• 3 IEEE transactions journal and 1 IEEE ECCE international conference publications

• A transactions publication selected as a highlighted paper in IEEE Trans. Power Electron in March 2019 issue

• Industrial collaborations with Delta-Q technologies on resonant converters for high power battery charging

Awards and Fellowships:

• Four Year Doctoral Fellowship (awarded for UBC’s best PhD students)

• Graduate Support Initiative Award (awarded for graduate and postdoctoral students of UBC)

We are grateful for all his contributions to the success of #martinordonezlab all these years and we wish him success in all of his future endeavors.

We would also like to thank Sup. Cmte.: Martin Ordonez, Wilson Eberle and Deepak Gautam; Examiner Cmte.:  Alireza Nojeh and Mauricio Ponga de la Torre; and Ext. Examiner: Olivier Trescases, for their participation.

Abstract for Sayed Abbas Arshadi’s PhD thesis
Title: “Three-Phase DC-DC Resonant Converters for High-Power Battery Charging Applications”

Abstract: Battery chargers are the power processing stage between energy sources and batteries. In order to be able to cope with newer technological requirements, higher efficiency, higher power density, and enhanced reliability are expected from this type of power converter. The purpose of this research is to increase the efficiency of power converters in high power Electric Vehicle (Electric Vehicle (EV)) battery charging applications. Compact size, high efficiency, and high reliability are specific requirements for high power battery chargers. This has been done by efficiently adopting three-phase DC-DC resonant configurations for battery charging converters. A thorough analysis on three-phase LLC resonant converters are done to better understand the current-sharing behavior of the converter. A current-sharing technique is proposed that improves the behavior of the converter effectively. A new modulation technique is also proposed that supports wide voltage regulation needed for battery charging applications. This technique also improves the efficiency of the converter at light-load operations, such as when the batteries are almost charged and not much more power is needed. In another part of this work, three-phase CLLC resonant converters are also studied for bi-directional battery charging applications. In this work, the behavior of the converter is analyzed and the effectiveness of the proposed current-sharing technique is verified.

In the recent months, Martin Ordonez Lab welcomed new team members as it strives to push the boundaries of Power Electronics and Renewable Energy.

As our newest recruits, we are thrilled to announce the addition of Navid, Howard, Gilbert, Gervasio, and Malinda to our team. The team is excited to work together as the addition of these new talent empower us in the pursuit of our goals.

With great contributions to the #powerelectronics & #rectifiers body of knowledge, Hamed Valipour has recently received his PhD degree! Congratulations Dr. Valipour! 👏

A month ago, Hamed defended his thesis on "High Efficiency Single-Phase Power Factor Correctors: Resonant Circuit and Flexible Topology" at The University of British Columbia, giving a grand finale to this key stage of his career. 


Hamed’s achievements include:
* 3 peer-rev. IEEE publications and 3 IEEE conference presentations
* Industrial collaborations with Alpha Technologies on #PFC #ResonantConverters, and #BatteryChargers
* Vice-Chair of the IEEE Power Electronics Society Chapter in Vancouver 

 Awards and Fellowships
* Four Year Fellowship Award 2016 - 2020, G+PS, UBC
* Grad. Student Initiative Award, 2018 & 2019, UBC

We are grateful to have had Hamed contributing to the success of #martinordonezlab all of these years and wish him the best with his new position at @SMPCT. We would also like to thank Chair Gary Schajer; Sup. Cmte. Martin Ordonez, Bill Dunford, Navid Shafiei; Examiner Cmte.: Shahriar Mirabbasi, and Mauricio Ponga; and Ext. Examiner Akshay Rathore, for their participation. As well as Mohammad Mahdavi for his constant contribution to Hamed’s work.

Abstract for Hamed Valipour’s PhD thesis

Title: “High Efficiency Single-Phase Power Factor Correctors: Resonant Circuit and Flexible Topology”

Abstract: Rectifiers with Alternating Current (AC) input and Direct Current (DC) output are required in many applications to regulate the output and provide a Power Factor Correction (PFC) capability. There are different applications for PFC rectifiers: wide-range and narrow-range. The purpose of this work is to propose two approaches to improve efficiency while keeping the performance high in both wide and narrow range rectifiers. Wide-range applications require PFC converters to support extended ranges of variations in the input voltage. A PFC converter capable of coping with a wide input voltage range, 90VRMS −530VRMS, would significantly decrease costs and streamline development. In this work, a reconfigurable PFC converter is proposed which provides a high and flat efficiency curve throughout the entire operating voltage range. The proposed reconfigurable converter has a flexible bridgeless structure with simple control, low current ripples, low common-mode noise, and startup inrush current handling capabilities. Narrow-range applications are also studied in this work which do not require a wide range of variations in their input. An advanced LLCC resonant structure is proposed in this work which improves the efficiency in narrow-range applications. The operation of this proposed concept is first developed in a switching-time scale and tested in a DC/DC environment, then a modified version is used with an AC input and bridgeless configuration. This converter can provide soft switching for all of the semiconductors without adding extra elements, by just using the passive components in the design as resonant tank. Therefore, the efficiency can be improved which potentially results in lower sizes for the passive elements. This converter can also provide a continuous input current despite using small inductances. This enables an inherent PFC capability with a single loop control architecture in the AC/DC version. This structure has a simple and symmetrical structure with easy control. The proposed converters in this work are theoretically and experimentally analyzed. Their performance is also compared with conventional structures. The proposed converters show efficiency improvements as well as better performance in this comparison.

Learn more about Hamed and his work by visiting our website.
https://open.library.ubc.ca/cIRcle/collections/ubctheses/24/items/1.0395745

Congratulations to Mehdi Mohammadi for receiving the IEEE PELS Prize PhD Thesis Talk Award! 

The contest consisted of 200sec. videos which were evaluated by three judges based on key aspects such as problem definition, design methodology, outcomes, and quality of the presentation.

Competing with people from all over the world, Mehdi, secured the prize with an outstanding presentation on Three-Layer Control Strategy for LLC Converters.

This is a great achievement for Mehdi and for MartinOrdonezLab team members who gave their support for making this research possible.

Many years of sustained research productivity and a solid thesis defense is what it takes to become a world class #powerelectronics PhD graduate. Congratulations Dr. Ali Saket!  

A month ago, Ali defended his thesis on "High-Efficiency and Low Noise Planar Transformers for Power Converters: Paired Layers Interleaving" at The University of British Columbia, giving a grand finale to this key stage of his career.  

His achievements include: 
* 18 peer-rev. IEEE publications, 3 IEEE presentations (3 under review)
* Industrial collaborations with Delta-Q technologies on #Magnetic #EMI, #ResonantConverters, and #BatteryChargers
* Mentor for 10+ undergrad co-ops 

Awards and Fellowships
* 2nd Best Paper Award of 2018: IEEE Trans. on Power Electronics
* Faculty of App. Sc. Grad. Award- 2016 to 2018 
* UBC J.K. ZEE Memorial Fellowship in Elec. Eng. 

We are grateful to have had Ali contributing to the success of #martinordonezlab all of these years and wish him the best with his new job at @SMPCT. 

We would also like to thank Chair Matthew Choptuik; Sup. Cmte. Martin Ordonez, Bill Dunford, Wilson Eberle; Examiner Cmte.: Shahriar Mirabbasi, and Bhushan Gopaluni; and Ext. Examiner Praveen Jain, for their participation.

Abstract for Mohammad Ali Saket’s PhD thesis

Title: “High-Efficiency and Low Noise Planar Transformers for Power Converters: Paired Layers Interleaving”

Abstract: Magnetic components of any switching power supply are usually the bulkiest part of the circuit and determine the overall height of the converter. The design and/or selection of magnetics can affect the selection and cost of all the other associated power components, besides determining the overall performance, size and form factor of the converter itself. Nowadays, many applications, such as consumer electronics, the automotive industry, and telecoms require high power density and low-profile power converters. The height of traditional magnetic cores often causes the form factor of power converters to be plump and bulky, so these cores cannot be used in such applications. To implement slim profile converters, the Planar Transformer (PT) has emerged, featuring low height, simple reproducibility, lower leakage inductance, and low thermal resistance. Despite all these benefits, due to the large overlapping areas and proximity of planar layers, PTs are notorious for having large parasitic capacitance, which significantly degrades the performance of the power converter. Capacitive effects in transformers are divided into two groups: inter-winding and intra-winding capacitance. The large inter-winding capacitance of PTs generates large amounts of Common-Mode (CM) noise, creating serious Electromagnetic Interference (EMI) problems. Intra-winding capacitance affects the efficiency and performance of the converter and can lead to loss of voltage regulation in the LLC resonant converter.

The inter-winding capacitance of PTs can be reduced to some extent by separating primary and secondary windings, at the cost of increased leakage inductance and AC resistance. On the other hand, interleaved structures that are used to minimize AC resistance and leakage inductance significantly increase the interwinding capacitance. Therefore, there is an unfortunate trade-off in transformer design when it comes to minimizing parasitic elements. In order to resolve this trade-off as well as problems resulting from PTs’ large parasitic capacitance, this dissertation develops new design methods that target the root cause of the parasitic capacitance problem. A detailed parasitic capacitance model is developed for PTs that relates the distributed capacitance of layers to the equivalent circuit of the transformer. This method provides a deep insight into how the arrangement of the transformer affects its equivalent capacitance circuit. Based on this model, the concept of paired layers is introduced that provides criteria to achieve zero CM noise generation ii in PTs. According to this concept, overlapping layers of primary and secondary can be selected and designed in a way that the overlapping does not generate CM noise. Layers that have this condition are called “paired layers” and they can be used to design a highly interleaved structure that not only has low AC resistance and leakage inductance but also generates almost zero amount of CM noise. Since the implementation of the method depends on the voltage distribution on the transformer’s winding, different types of power converters are divided into three groups and the method is developed for each group. Multiple examples are provided for different types of windings, different turn ratios, and different topologies to show the generality of the method and make it easy to understand. The proposed method is validated using analysis, Finite Element Method (FEM), and experiments.

Besides the paired layers interleaving method, this dissertation studies the detrimental effects of PT’s large intra-winding capacitance on light-load voltage regulation of LLC resonant converter. It is shown that large intra-winding capacitance of PTs distorts the transformer’s voltage under the light-loading condition which results in loss of voltage regulation. To resolve this issue, six different winding layouts with very low intra-winding capacitance are presented. Using the proposed winding layouts, it is shown that the converter can regulate the output voltage even under no-load condition. These winding layouts also can be used to design wide-range planar inductors with very high self-resonant frequency, which is very desirable in high frequency operation.

We highly recommend this for people in the power electronics community, especially those interested in rsonant converters and electric vehicles. The talk is based on the paper "Unbalanced Three-Phase LLC Resonant Converters: Analysis and Trigonometric Current Balancing" authored by Sayed Abbas Arshadi, Mohammad Ali Saket, and Martin Ordonez from MartinOrdonezLab in collaboration with Wilson Eberle form UBC and Marian Craciun and Chris Botting from Delta-Q Technologies.

The webinar will be presented by Sayed Abbas Arshadi and Martin Ordonez on Wed, Apr 15, 8:30 AM - 10:00 AM PDT.

Link for registration:
https://register.gotowebinar.com/register/2585816459057799694

Link to paper:
https://ieeexplore.ieee.org/document/8379448

Mr. Ignacio Galiano Zurbriggen has recently become Dr. Galiano! Congratulations Nacho!

Last month, Nacho defended his Ph.D. thesis at The University of British Columbia concluding an extremely fruitful stage in his career. We are thrilled with his attainment and are honoured to have him continue working with us at MartinOrdonezLab.

His achievements include:
* Over 20 peer-rev. IEEE publications, 9 IEEE presentations, and an IEEE seminar
* Industrial collaborations with Alpha Technologies on Solar, Wind, Telecom and multilevel converters
* Research exchange: GREP - Universitat Politècnica de Catalunya
* Instructor of Appl. Electronics and Electromechanics at UBC, and renewable energy and digital tech. courses for UBC's VSP
* Mentor for UBC Sustaingineering and 20+ undergrad co-ops

And awards:
* Go Global - 2017 * Killam GTA - 2016/17
* APSC Research Excellence - 2013 to 2016
* IEEE APEC Outstanding Presentation - 2013/14

We thank Chair Madjid Mohseni; Sup. Cmte. Martin Ordonez, Jose Marti, Bill Dunford; Univ. Examiners: John Madden, Ryozo Nagamune; and Ext. Examiner Yan-Fei Liu, for their participation.

Abstract for Ignacio Galiano Zurbriggen’s PhD thesis

Title: “Large-signal Transient Control in Power Electronics: an Average-Geometric Framework”

Abstract: Switch-mode power converters are a fundamental component of modern power systems; they are ubiquitous in renewable energy applications, electric vehicles, battery chargers, and power supplies. Controllers are an essential component in power converters as they improve the converter's dynamic behavior during transients and in steady-state. For decades, the power electronics industry has preferred to utilize controllers based on converter small-signal analysis due to their low implementation requirements and in spite of their dynamic performance limitations and global stability issues. On the other hand, excellent dynamic response and global stability are achieved by non-linear boundary controllers based on state-plane analysis, which usually have much higher implementation requirements. This thesis focuses on the dynamic performance improvement of power converters by incorporating state-plane concepts while maintaining low implementation requirements to facilitate the large-scale adoption of the technology. By combining traditional averaging modelling tools with state-plane analysis, the unified Average Natural Trajectories (ANTs) are obtained to accurately model the large-signal dynamic behavior of the fundamental topologies (buck, boost, and buck-boost). As a result, the proposed framework establishes the foundation for several dynamic performance improvement efforts introduced in this thesis. Employing the ANTs as a large-signal model, the theoretical limits of dynamic performance are defined and used to develop a powerful benchmarking tool, providing great value for design engineers. Furthermore, a unified controller based on the ANTs model is developed for the fundamental topologies in this work. This controller features a predictable large-signal response and outstanding dynamic performance while maintaining low implementation requirements. The ANTs modelling approach is also extended to photovoltaic applications to develop an extremely fast maximum power point tracking method for scenarios that include rapidly changing environmental conditions. Finally, the concept of dual-loop geometric control is introduced by combining state-plane analysis with an industry-standard dual-loop control structure, thereby bridging the gap between industrial applications and state-plane controllers. The concepts introduced in this thesis are supported by thorough mathematical analysis and validated by extensive simulation and experimental results. This thesis significantly contributes to the advancement of the field of modelling and control for power electronics. 

It takes many years of hard work and dedication to conclude a PhD with such exceptional results: congratulations Francisco Paz!
Some of Francisco's PhD highlights:
* Over 15 IEEE Publications
* Industrial Collaboration with Alpha Technologies in PV, Wind, Multilevel Converters, and Telecom DC Systems.
* Vice-Chair of the IEEE Power Electronics Society Chapter in Vancouver (Outstanding Small Technical Chapter 2016, 2018)
* Instructor for courses on renewable energy and digital electronics in the UBC Vancouver Summer Program

Awards and Fellowships
* Killam Graduate Teaching Assistant Award
* Best Paper Award at PEDG
* Four Year Fellowships
* Faculty of Applied Science Graduate Award
* ICICS Graduate Scholarship

With these accomplishments and much more under his belt, Francisco Paz defended his PhD thesis at @The University of British Columbia concluding a key milestone in his career. We're both proud and honoured to have been part of Francisco's success and are delighted to have him continue working with us at #MartinOrdonezLab.We would like to thank the Chair, Dr. Anthony Lau; Supervisor Committee, Dr. Martin Ordonez, Dr. John Madden and Dr. William Dunford; and University Examiners, Dr. Andre Ivanov, and Dr. Elod Gyenge, for their participation.

Abstract for Francisco Paz’s PhD thesis

Title: “Advanced Monitoring and Control of Distributed DC Systems: An Embedded Impedance Detection Approach”

Abstract: Direct Current (DC) systems, made possible by power electronics technology, are becoming more prevalent due to their advantages when integrating renewable energy sources, energy storage, and DC loads. Microgrids and local area energy systems are instrumental to DC systems, and much progress has been made around them. However, DC microgrids face numerous challenges due to their decentralized nature, such as resource optimization, control, and protection. This thesis focuses on developing a core technology, an embedded impedance detection (EZD) method for DC systems, and its application to five critical challenges in DC systems. The proposed method uses a reference signal of minimal amplitude and high frequency, injected in the control loop of the power electronics converter, and a digital Lock-In Amplifier to extract the incremental behavior of the voltage and current around the DC operating point. These can be used to calculate the incremental impedance in the resistive and reactive term, which are representative of the reactive part of the system as well as the nonlinear characteristics of the system. The proposed EZD method is applied to address five critical problems in today's DC systems: 1) adaptive control in the presence of active loads - to expand stability and improve transient response; 2) islanding detection - to detect the connection and disconnection of the utility grid and change controllers for autonomous operation; 3) fault location - to detect the distance to a fault and simplify the system restoration; 4) high-impedance fault detection - to accurately distinguish a fault condition from a load increase; and 5) maximum power point tracking of photovoltaic panels - to ensure efficient energy harvesting. For all these applications, the proposed EZD-based solution offers critical benefits and advantages, such as high sensitivity and accuracy at a low system disturbance and fast detection. The work presents a detailed analysis of the proposed EZD technique as well as considerations for its implementation in commercial microcontrollers, followed by simulations to illustrate its capabilities. The thesis also presents a detailed analysis of each DC system application and its particular considerations. The outlined benefits are supported by simulations and validated through experimental results using a real power electronics platform.

In early December, Celeste successfully defended her MASc thesis to conclude her program and continue with us pursuing her PhD. 

Celeste’s great achievements include but are not limited to the following:  

• 3 IEEE International Conferences Publications (1 as the first author),

• Collaboration with other lab members in 1 IEEE Journal Publication (submitted), 

• Great contributions in collaboration with Alpha Technologies Ltd. on PFC power losses estimation, design, and optimization. 

We congratulate Celeste for achieving this significant milestone in her career and wish her success in her PhD program! 

Abstract for Celeste’s MASc thesis

Title: “Accurate Power Loss Models of Complex Converters”

Abstract:Power loss estimation is essential for the design and optimization of power converters. Traditionally, the power loss estimation is done using datasheet-level information about the switching devices. However, this information is limited to isolated operating points, compromising the accuracy of the estimation. In addition, the representation of PCB effects and gate driver, which cannot be considered by using datasheet parameters, increase the complexity of the tasks by adding more unknown magnitudes and more complex equations without guaranteeing their correct estimation.

In this work, a novel power loss estimation method, which can be applied to any topology, is presented. This proposed method utilizes Design of Experiments (DoE) and Response Surface Methodology (RSM) to model the different types of losses in all the elements in a power converter such as power switches, diodes, and inductors. With RSM simple equations explain the different types of losses as a function of variables that directly affect them allowing the losses estimation under any operating condition accurately. These models are extensively validated to show the advantage of using the proposed method and significant improvement with respect to datasheet calculations is obtained. For complex topologies such as Power Factor Corrector (PFC), accurate power loss estimation is not only necessary but also a challenge. To show the capabilities of the proposed model, it is applied to Universal PFC, which is a complicated converter in terms of loss calculation and analysis. By using the proposed models, the inductor is designed optimally and the optimal switching frequency is selected to minimize the losses in the different input voltage levels. Experimental validation of the proposed method, prediction, and design impact is presented; the proposed method yields a power loss reduction up to 40%, having the greatest improvement at an input voltage of 110 V, and an output power higher than 500 W.

Mohammad Ali Saket won the  second Place for 2018 Prize Paper Awards: IEEE Transactions on Power Electronics.  This is a great achievement for him and the #martinordonezlab.

“It took 2 years and many experiments, but winning the second prize paper of the year made it worthwhile.” says Mohammad Ali Saket. He also mentioned that this prize is the results of cooperation with Dr. Navid Shafiei, Chris Botting, Marian Craciun and #martinordonezlab.

The paper can be found here:

https://lnkd.in/dqNQuDd

M. A. Saket, M. Ordonez, and N. Shafiei, “Planar transformers with near-zero common-mode noise for flyback and forward converters,” IEEE Trans. Power Electron., vol. 33, no. 2, pp. 1554–1571, Feb. 2018.

We are very proud of the tremendous progress made by UBC Sustaingineering Team. Its story of success has been recently published at UBC Life Blog. The team, originally founded by Martin Ordonez, has this year an outstanding workforce with more than 50 students from different disciplines and is led by Abdul Moiz, Sajan Rajdev and Jorge May one of the grads at Martin Ordonez Lab.

UBC is full of passionate individuals trying to make the world a better place. Sustaingineering is a club where such individuals work to achieve sustainable solutions for the problems in our world. The team was founded by Dr. Martin as a source of motivation for encouraging students to empower change. While Sustaingineering it is still a young club, they have done some remarkable work already. In partnership with ENICALSA, they developed a remote monitoring system for solar water pumps located in remote communities in Nicaragua.  Since it foundation Sustaingineering has been sponsored by the Fred Kaiser foundation for higher education and the faculty of Applied Science at the UBC.

To learn more please visit the UBC Life Blog’s article.

Coordinated by Daniel Hsu, Divyank’s work contributed to key research, conducted in our lab by German Nahuel Bogado and Gabriel Ferreira da Silva, that is pushing the frontiers of electric vehicle battery charging systems. Divyank worked on the development of advanced tools that enable the accurate modelling of critical components in the system.

From MITACS Impact Stories:

“Timing is everything. In cleantech innovation, it’s the difference between leading and falling behind. For Professor Martin Ordonez’s team at the UBC Department of Electrical & Computer Engineering who work in power electronics and conversion, one of the ways of being ahead is developing clean energy through research in renewable electric vehicles (EV) and power storage.

“We work on power conversion. It’s a timely, much needed area of work. EV is a logical application for renewable storage. We’re part of an ecosystem. Companies who need talent are moving into this field. We want to make sure we can capture that talent,” says Ordonez.

Governments and industry think so too, having committed to over $10 million for this research area. With this project, vehicles and buildings become active participants in city-scale energy transactions.

Professor Ordonez has plenty of talent in his lab. His team works on a wide range of battery research. For Divyank Singh, a senior undergraduate Engineering student from India’s Manipal Institute of Technology visiting Canada this summer as a Mitacs Globalink Research Intern (GRI), the opportunity to work in Ordonez’s lab is a dream come true.

“I reached out to Dr. Ordonez even before I knew about Mitacs’s GRI program. I’m researching front-end EV battery power conversion at the power outlet and charger connection. A major challenge is estimating the right size of battery for parkades,” says Divyank.

He is also supporting other students who work on power conversion with a testing platform he developed using the equipment available in Ordonez’s lab. The automation platform he designed measures raw values. It’s proving invaluable for his project but also for modelling and simulation of much larger batteries.  

“With a major scarcity of fossil fuel, and clear global sustainability goals, we need to develop efficient, non-polluting solutions,” says Divyank.

While his work specifically focusses on the point of charging in a parkade, it will also inform batteries that can be scaled up to deliver renewable energy at a community level. “I’m developing a platform for testing modelling which will aid estimation of size and bring us one step forward to solving that challenge.”...”

To read more, please visit MITACS Impact Stories webpage.

The contest consists of 200 seconds videos which are evaluated by three judges based on key aspects such as problem definition, design methodology, outcomes, and quality of the presentation.

Competing with people from all over the world, Emanuel, from #MartinOrdonezLab, secured the prize with an outstanding presentation on Advanced Control Functionalities for Photovoltaic and Energy Storage Converters. His talk will be presented at the end of September at The Eleventh Annual Energy Conversion Congress and Exposition, at Baltimore, Maryland, USA. 

Congratulations Emanuel for this great achievement!

Last Monday, on the 29th of July 2019, Matthieu Amyotte successfully graduated from his MASc program in our lab. Matt’s great achievements include but are not limited to the following:

• 3 IEEE International Conference papers (one as first author) and 1 IEEE Journal publication (submitted).

• Major contributions to our UBC Sustaingineering Team.

• Key involvement in the research collaboration projects with our industry partner, Alpha Technologies Ltd., on WBG switch losses.

• A number of great contributions to our lab’s operations and logistics

Right after graduation Matt successfully transitioned to the industry by taking a position at Corvus Energy, Richmond, BC.

We congratulate Matt for achieving this significant milestone in his career and wish him success in all future endeavours!

Abstract for Matt’s MASc thesis
Title: “Improved Power Loss Estimation for Device- to System-Level Analysis”
Abstract: Power converters are found nearly everywhere electric power is used and are ubiquitous in renewable energy generation and electric vehicles. Power converters transform electricity between alternating current (AC) and direct current (DC) electricity and change the voltage level (AC or DC). Modern power converters have very high efficiency, often reaching peak efficiency > 95%. However, the losses in these systems are still significant and must be considered for thermal and financial purposes. For example, a 1% efficiency improvement from 98 to 99% corresponds to a 50% reduction in losses. This would allow for a significant reduction, if not the complete elimination, of the thermal management system. To enable maximum loss reduction, a thorough understanding of the losses in power converters is necessary. In particular, accurate prediction of the losses at the design stage allows designers to create better power converters and energy systems with lower losses. Gallium Nitride (GaN) power switches are an emerging technology due to their high efficiency operation and smaller size compared to traditional Silicon (Si) devices. To date, traditional topologies, such as boost and resonant converters, have been implemented with Gallium Nitride (GaN) devices, and simplistic power loss models have been employed for loss predication and thermal management design. However, these simplistic models do not provide accurate loss prediction, resulting in over-design of the thermal management systems. Meanwhile, high accuracy power loss analysis tools for GaN devices are missing in the literature. With very small footprints and thermal capacity, accurate power loss prediction for GaN is mandatory. This work proposes a comprehensive method to predict conduction and switching losses in GaN devices. Through the use of thermal measurement, the inaccuracy of traditional electrical measurements for power losses is eliminated and a higher accuracy model is achieved. The proposed model is verified experimentally against common traditional approaches. The proposed model provides a nearly four-fold reduction in loss prediction error across a variety of operating conditions. Ultimately, the model provides confidence in loss prediction, allowing power converter designers to effectively design thermal management systems for maximum power density and efficiency. Having established accurate converter-level loss prediction, a higher level of abstraction is then considered. The rapid expansion of distributed energy resources has led to increasingly complex systems with numerous power converters. Given the pervasiveness of power converters in both large grids and microgrids, accurate converter loss prediction is essential for system-level financial and reliability evaluation. Existing system-level analysis focuses on distribution losses and oversimplifies converter losses by assuming fixed efficiency. In reality, converter losses are highly variable under different operating conditions. However, the multi-domain simulation tools employed for GaN loss prediction at the converter level are too slow to be applied to system-level analysis. In this work, the Rapid Loss Estimation equation (RLEE) is proposed to provide computationally simple loss prediction under all operating conditions. First, the real operating conditions are determined for the intended application. Then, accurate loss information is extracted from detailed converter behavior in multi-domain simulations at select operating conditions. Finally, the RLEE is obtained: a parametric equation which is fast enough for system-level simulation while capturing the converter’s complexity at different operating conditions. Three different converters are considered: one for solar generation, one for electric vehicle charging stations and one for battery storage. These converters are simulated in a DC microgrid to highlight the benefits of the proposed loss estimation tool. Ultimately, the tools developed in this work provide improved loss estimation in power converters from the component level through to the system level. The proposed techniques, while explained through specific examples, are widely applicable and can be readily implemented to other devices, topologies and systems. Improved loss estimation is valuable at all levels of abstraction, from designing thermal management systems for individual devices in a converter to optimizing the financial outcomes of a complex grid with multiple power converters.

Last Friday, on the 5th of July 2019, Mehdi Mohammadi successfully graduated from his PhD program in our lab. Mehdi’s great achievements include but are not limited to the following:

• Over 10 IEEE Publications.

• A patent.

• President of the UBC’s ECE Graduate Student Association (@ECEGSA).

Right after graduation Mehdi successfully transitioned to the industry by taking a position at Fortinet Technologies (Canada).

We congratulate Mehdi for achieving this significant milestone in his career and wish him success in all future endeavours!

Abstract for Mehdi’s PhD thesis
Title: “Three-Layer Control Strategy for LLC Converters: Large Transient, Small-Signal, and Steady-State Operation”
Abstract: Resonant converters, particularly LLC converters, feature low switching losses and electromagnetic interference (EMI), and high power density and efficiency. As a result, they have been widely used in DC/DC applications. Although LLC converters naturally provide soft switching conditions and therefore, produce relatively less switching losses, conduction losses in their rectifier have remained a barrier to achieving higher efficiencies. Moreover, the analysis of LLC converters is complicated since they process the electrical energy through a high-frequency resonant tank that causes excessive nonlinearity. The issue of this complexity becomes even worse since, in reality, the resonant frequency of such converters deviates due to variations in the temperature, operating frequency, load, and manufacturing tolerances. This complexity has caused:

• limited research on large-signal modeling and control of LLC converters to be performed (this leads to uncertain large-signal transient behavior and sluggish dynamic/recovery response).

• limited insight into small-signal modeling of LLC converters (this often leads to low accuracy).

• unregulated LLC converters not to operate in their optimum operating point (this leads to degraded efficiency and gain).

• conduction losses in the LLC rectifier to remain the main challenge to achieve higher efficiency

To address the above concerns, in this dissertation, a three-layer control strategy is introduced. Based on the need, all the three layers or just one of them can be used when implementing the LLC converter. The three-layer control strategy produces accurate and fast dynamics during start-up, sudden load or reference changes with near zero voltage overshoot in the start-up, obtains a near zero steady-state error by employing a second-order average small-signal model valid below, at, and above resonance, improves efficiency by a new synchronous rectification technique, and also tracks the series resonant frequency in unregulated DC/DC applications.