Tutorials
A large collection of excellent tutorial sessions will be offered from 8:30 to 4:30 on Monday, June 27th at Hyatt Regency Hotel for those deciding to register for the tutorial sessions. The following tutorials will be offered:
Tutorial 1: Reliability of Power Electronics Converters for Renewable Energy Systems
Tutorial 2: Extreme Control Performance for Power Electronics
Tutorial 4: Challenges and Trends in Magnetics
Tutorial 8: Real-Time Power Electronic Plant Model Generation for PLECS RT Box
All tutorial attendees are invited for lunch and the according coffee breaks.
Tutorial 1: Reliability of Power Electronics Converters for Renewable Energy Systems
by Frede Blaabjerg and Huai Wang (Aalborg University)
In recent years, the automotive and aerospace industries have brought stringent reliability constraints on power electronic converters because of safety requirements. Today customers of many power electronic products expect up to 20 years of lifetime and they also want to have a "failure free period" and all with focus on the financials. The renewable energy sectors are also following the same trend, and more and more efforts are being devoted to improving power electronic converters to account for reliability with cost-effective and sustainable solutions.
The objective of this tutorial is to introduce the recent progress in the reliability aspect study of power electronic converters for renewable energy applications. It will cover the following contents: the motivations for highly reliable electric energy conversion in renewable energy systems; the reliability requirements of typical renewable energy systems and its implication on the power electronic converters; failure mechanisms and lifetime models of key power electronic components (e.g., power semiconductor switches, capacitors, and fans); long-term mission profiles in Photovoltaic (PV) and wind power applications and the component level stress analysis; reliability analysis methods, tools, and improvement strategies of power electronic converters for renewable energy systems. A few case studies on PV and wind power based renewable energy systems will be discussed throughout the tutorial.
The approaches presented in the tutorial are also the common interest for the companies involved in the Center of Reliable Power Electronics (CORPE) at Aalborg University. The tutorial will also present the views of the instructors on the future research opportunities in the area of reliability of power electronics.
Tutorial 2: Extreme Control Performance for Power Electronics
by Martin Ordonez, and Ignacio Galiano (University of British Columbia)
Controllers for power converters are responsible for ensuring good dynamic response, stability, power quality, and regulation. For decades, the field of power electronics has relied on small-signal modeling and frequency response analysis to control power converters, which often results in sluggish and limited performance controllers. In particular, since distributed generation converters (solar, wind, storage) switch at moderate frequencies 2 -25kHz, control bandwidths with traditional controllers are very limited resulting in poor behaviour.
This tutorial presents control strategies with extreme performance based on simple and intuitive geometrical analysis. The tutorial begins by reviewing the major hurdles/issues of traditional controllers (small-signal) and providing the fundamentals in developing advanced controllers with outstanding dynamic response. The theory aims at understanding the physical dynamic limits of power converters and developing control laws based on natural trajectories. From fundamentals to advanced applications, the tutorial will explore a number of topologies and provide comprehensive insight into their transient characteristics. Experimental design examples will be presented as part of the tutorial.
Tutorial 3: Control of Power Electronics Systems using Predictive Switching Sequences and Switching Transitions
by Sudip K. Mazumder (University of Illinois)
This tutorial provides a fundamentally different perspective to control of switching power electronic systems. It is based on controlling the time evolution of the switching states (i.e., switching sequences) as well as controlling the switching transition of the power semiconductor device of the solid state electronic system. The former - i.e., switching-sequence based control (SBC) yields rapid response under transient condition, optimal equilibrium response, and yields seamless transition between the two states of dynamics. The first part of the tutorial will primarily focus on SBC for power electronics systems. By enabling integration of modulation and control, SBC precludes the need for ad-hoc offline modulation synthesis. In other words, an optimal switching sequence for the power converter is generated dynamically without the need for prior determination of any modulation scheme (which generates a pre-determined switching sequence) in typical conventional approaches.
One of the fundamental distinctions between SBC and conventional model predictive control (MPC) is that SBC ensures optimal determination of the switching sequence of the power converter under stability bound. The tutorial will provide the mechanism to carry out SBC and MPC control syntheses and demonstrate the differences between SBC and MPC. Several device, converter, and network level implementations (e.g., microinverter, microgrid, parallel inverters, multilevel converter, aircraft power system) of the SBC will be provided encompassing author's multiple years of project experience encompassing leading advanced defense and energy industries.
Finally, the tutorial will focus on switching transition control (STC). The primary objective of STC is to demonstrate how key power electronic system parameters including dv/dt and di/dt stress, switching loss, electromagnetic noise emission can be controlled dynamically by modulating the dynamics of the power semiconductor devices. Both electrical and newly developed optical control mechanisms to achieve STC will be demonstrated. In the context of the latter, mechanisms for monolithic integration of switching sequence control as well as switching transition control will be outlined and the revolutionary impact of such a novel integration on system performance will be demonstrated with practical applications.
Tutorial 4: Design Challenges for High Frequency Magnetic Circuit Design for Power Conversion
by William Gerard Hurley (National University of Ireland)
The key to reducing the size of power supplies is high frequency operation and magnetic components can play a critical role. The seminar begins with the design rules for inductor design and examples of different types of inductors are given. A special example is the inductor in a flyback converter, since it has more than one coil. This is followed by the general design methodology for transformers and many examples from switched mode power supplies and resonant converters are given. The main focus is placed on modern circuits where non-sinusoidal waveforms are encountered. General rules are established for optimising the design of windings under various excitation and operating conditions. The skin effect and the proximity effect give rise to increased losses in conductors due to the non-uniform distribution of current in the conductors. A new approach to high frequency losses that avoids cumbersome Fourier analysis will be presented to optimise the winding design, for non-sinusoidal waveform encountered in power electronics. Core losses for both sinusoidal and non-sinusoidal flux will be covered. This seminar is of interest to graduate students and practising engineers working with power supplies and energy conversion systems.
Tutorial 5: Speeding up Grid-Link Inverter Development with Offline, Processor-In-Loop (PIL), and Hardware-In-Loop (HIL) Simulation
by Albert Dunford (Powersim)
The Design of Grid-Link inverters is a complex process involving the selection and sizing of the power stage, the development of a control algorithm, and the implementation on to a DSP or MCU. The implementation and development of the control algorithm is usually very involved as testing its response under various operating conditions is essential to ensure safe operating conditions. In order to reduce the development time and cost, a well suited simulation and design approach is required.In this tutorial, we will look at the advantages gained by using an offline simulator, PIL, and HIL simulations as a design strategy to reduce cost and development time. We will show how a grid-link inverter with a digital control algorithm can be implemented in PSIM. PSIM will then be used to automatically generate the embedded c code that will be used on the target DSP. We will then program the target DSP with the generated code and use it to perform a PSIM-PIL simulation to verify the operation of the code with a simulation of the PSIM power stage. The DSP execution will also be tested with a real-time Hardware-In-Loop simulation. In each stage of the simulation and design cycle we will look at what can be learned and tested for with each style of simulation. The design methodology will be applicable for any project that involves high powers or voltage levels with a digital control implementation.
Tutorial 6: Electric Springs - A Smart Grid Technology for Taming the Intermittent Nature of Wind and Solar Power
by Ron S.Y. HUI and Chi Kwan LEE (The University of Hong Kong)
With the CO2 concentration passing the 400 ppm mark, there is an urgent need to substantially increase wind and solar power penetration as soon as possible. The success of the 2015 Paris Climate Change Summit has resulted in many countries setting targets in reducing greenhouse gas emission. One obvious solution is to substantially increase renewable energy generation. However, the intermittent nature of wind and solar power has been identified as a de-stabilizing force to the power grid. It is envisaged that more stability issues will evolve as the amount of renewable power generation increases. With more distributed power generation, the control paradigm has to be changed so that ‘the load demand will follow the power generation', in contrast to existing control paradigm that ‘the power generation follows the load demand'.
In this tutorial, we shall introduce the concept of electric springs as a smart grid technology for demand response. Based on power electronics technology, Electric Spring is a new distributed technology that can (1) tame the intermittent nature of wind and solar power and (2) ensure ‘the load demand to follow the power generation'. Electric springs are power electronic circuits that act as ‘active suspension' systems. When distributed over the distribution networks, they provide a robust stability support system for future power grid. The Electric Spring concept can be incorporated easily either (1) into non-critical electric appliances, (2) as part of the power supply infrastructure or (3) into grid-connected wind/solar power inverters.
The tutorial will cover (i) the basic Electric Spring concept, (ii) various forms of electric springs and their functions, (iii) the application potentials in mitigating voltage/frequency fluctuationsin power grids, peak load shaving, reducing power imbalance, and reducing energy storage requirements, (iv) hardware and control designs, (v) dynamic modeling for power system simulation studies. Practical results obtained from a 100kVA hardware setup will be included for illustration. At the end of the tutorial, new industrial projects and future trend of demand response and power system infrastructure will be addressed.
Tutorial 7: HIL and RCP capabilities of real-time digital simulators for MMC and other power converter applications
by Maxim Beaudoin and Wei Li (OPAL-RT Technologies)
The Modular Multilevel Converter (MMC) is an emerging topology suitable for very high voltage applications that has been increasingly commissioned around the world as a result of its significant advantages. To guaranty the most efficient performance and mitigate risks associated of any malfunctions, it is crucial for MMC manufacturers to tests their controllers, and to validate for all possible scenarios using a hardware-in-the-loop (HIL) test bench before they are commissioned in the field. However, due to the complexity of MMC control and the level of engineering expertise required to operate these systems, it has become the norm to resort to third-party experts to provide the cutting-edge technologies dedicated to the hardware verification of new control algorithms for new and existing power electronic converter.
With nearly two decades of expertise in the development of PC/FPGA Based Real-Time Simulators, Hardware-In-the-Loop (HIL) testing equipment and Rapid Control Prototyping (RCP) systems, OPAL-RT Technologies is a world leader in engineering equipment and software used for experimental work on converter interactions and network control. This tutorial will explain the main challenges of an HIL test bench for a complicated MMC system and the solutions provided by OPAL-RT Technologies. The capabilities of the test bench for fast or real time simulation, and rapid control prototyping (RCP) study of power girds and renewable energies with power electronic devices will be covered. A live technical demo will also be executed to demonstrate how the scalable OPAL-RT's platforms can perform consecutive automated tests and protection scheme under various fault conditions for small MMC system with few cells or very large simulator for MMC system including thousands of cells.
Tutorial 8: Real-Time Power Electronic Plant Model Generation for PLECS RT Box
by Kristofer Eberle (Plexim)
Power converters are sophisticated systems composed of multiple subsystems, including hardware and software components. Their design is a complex task requiring advanced tools and processes. When such systems are developed for high power applications and include converters connected to the electric grid, as is the case with distributed generation systems, practical testing with hardware can be challenging. Replicating scenarios such as grid faults and islanding is more feasible in a model environment. Hardware-in-the-Loop (HIL) platforms allow for real time testing of the embedded control system with a virtual model of the electrical system and within the safety of the lab.
Plexim develops and markets design tools for the development of power electronic systems. The company's electrical engineering software PLECS, now widely adopted in various industries and academia worldwide, is a complete power conversion system simulation package that yields robust and fast results. Plexim recently added a HIL offering to its portfolio. The PLECS RT Box is designed for real-time testing of a hardware control system and rapid control prototyping.
In this tutorial, we will explore an example design life cycle for a grid-connected solar system application. The workflow consists of using PLECS for model development in conjunction with the RT Box for verification of a real controller. We will demonstrate the generation of discretized code for the PV inverter model and show how the fidelity of the model can first be verified by means of running the generated code within PLECS. Once the discretization step size is tuned to satisfaction, the real-time code will be deployed onto the PLECS RT Box. Waveforms demonstrating the proper operation of the control algorithms executing on a TI LaunchPad will be shown both on a real oscilloscope as well as on the new PLECS soft-scope.