Canras Batunlu

Guide to Modeling and Simulation

In this chapter, a step-by-step guide for simulation and models used in this book is explained. Finite element models using COMSOL and MATLAB/Simulink codes’ writing procedures are outlined in easy to follow points. Those include thermal model of a single switch power module, thermomechanical model of a dual power modules and a single-switch discrete switching devices. Modeling of wind and solar renewable energy systems, using MATLAB/Simulink, with thermal characterisation of the associated power electronic devices are also explained.

Real-time system for monitoring the electro-thermal behaviour of power electronic devices used in boost converters

Abstract Reliability of power electronic devices (PEDs) is a key issue to secure power supplies in modern word, especially, those generated from renewable energy sources. Thermal stress due to switching frequency and environmental conditions are commonest cause of currently unsatisfactory PEDs reliability scores. In this paper, the electro thermal performance of PEDs and related parameters are critically investigated using three types of differently manufactured insulated gate bipolar transistors (IGBTs). Namely, punch through (PT), non-punch through (NPT) and field stop (FS) silicon trench gate technologies. First, currents and voltages of the examined IGBTs were measured under different operating temperatures, switching frequencies and electrical loading conditions. Second, power losses of the examined devices were calculated, in real time, based on their measured currents and voltages using realistic mathematical model embedded in a dSPACE system. Subsequently, the power losses for each device were used as an input to a finite element model to graphically predict heat distributions for each of the monitored devices. Compared to expensive measurements taken by high-resolution thermal imaging cameras, the accuracy of the developed system achieved 97%. The obtained results demonstrate the developed model would serve as an inexpensive and powerful tool for monitoring PEDs thermal conditions.

Thermal Analysis of Power Electronics: Review

This chapter reviews recent work done on thermal characteristics of power electronic converters and their electronic components. The review process is divided into electrothermal, thermomechanical modeling, lifetime analysis of semiconductor switching elements, and materials properties effects on the reliability of power electronic converters in wind and solar energy applications. Achievements, shortfalls, and remaining tasks for future investigations are also outlined throughout the chapter.

Thermal Analysis of Wind and Solar Systems

This chapter presents case studies on lifetime and reliability analysis for power electronic devices based on the electrothermal and thermomechanical characteristics. Model outcomes are validated, in real time, using dSPACE system with a physical permanent magnet generator based wind turbine system test rig. Effects of maximum power point tracking algorithms on lifetime and thermal stresses in DC–DC converters under different operating conditions are also studied. Converter’s electrothermal characteristics were first modeled. Subsequently, experiments on photovoltaic solar system were carried out using two different MPPT algorithms, namely, perturb and observe (P&O) and incremental conductance (IC).

Thermal Characteristics of Boost Converters

The thermal behavior of DC–DC boost converters is studied in this chapter. A mathematical electrothermal model, developed in previous chapters, is embedded in dSPACE real-time system to predict temperature and power losses of four physically built DC–DC Boost converter units, designed with three topologically different insulated gate bipolar transistors (IGBTs) and one with a SiC MOSFET device. Subsequently, predicted power losses are used by finite element models (derived in COMSOL) to estimate heat distribution in the monitored devices.

Fundamental Thermal Characterization of PECs

The implementation of an electrothermal, 3D finite element model for a multichip single IGBT power module is presented in this chapter. The model was built with COMSOL finite element package. Based on the thermal profile extracted from finite element (FE) analysis, a compact electrothermal model was implemented in discrete z-domain with MATLAB/Simulink for continuous temperature estimations over each layer based on the heat interactions and coupling effect across IGBT/diode chips.

Inverters Thermal Behavior

The developed models is utilized in this chapter for investigating thermal characteristics of DC–AC inverters. The physical properties and performance of a commercially adopted inverter chip was studied and realistic model was derived to understand its behavior. Subsequently, model’s outcomes and performance was experimentally evaluated using purposely constructed test rig. The experimental validation of thermomechanical finite element model and the proposed switching control method with variable DC link operation were achieved via dSPACE RTI by using a three-phase inverter module; namely the FS10R12VT3 by Infineon Technologies. This device is a scaled-down module of the FF1000R17IE4 which is constructed with six pairs of IGBT/diode chips. It is more suitable to be tested under laboratory condition due to its low-power capacity.

Thermal Stress Effects on Reliability

In this chapter, thermomechanical modeling and effects of thermal stress on reliability of power electronic converters are presented. This was carried out taking account of variations in wind and irradiance characteristics. A mitigating technique is also described by first, developing realistic full scale (FS), and partial scale (PS) induction generator models combined with a two level back-to-back PEC. Subsequently, an algorithm was derived to mitigate temperature effects by controlling its switching pattern. Algorithm’s effectiveness was experimentally verified using a three-phase DC–AC inverter module attached to scaled wind turbine system.

3D thermal model of power electronic conversion systems for wind energy applications

Energy is vital for continual progress of human civilization. Accessing to low-cost, environmental friendly, renewable energy sources are keys to economic future for developing countries and around the globe. Wind energy systems are one of the most adequate option where power electronic converters are used for monitoring and conditioning the energy flow; however operating environmental conditions such as variable wind speed cause temperature fluctuations that derive degradation and failures in these systems. Therefore, proper thermal management and control are necessary to monitor their reliability and lifecycle. Besides, power capacity of these devices is being increased by new technological improvements such as multichip designs. Meanwhile, the heat path through the devices has also become more complex due to the heat coupling effect among several chips and it is not possible to be estimated by conventional methods found in literature. In this paper, a three dimensional finite element model (FEM) is implemented for accurate estimation of thermal profile of a power module. Based on the thermal characteristic obtained by the FEM, an electro thermal model was developed to predict the temperatures of each layer of the power module that cannot be measured during service. The work is essential as it solves massive heat transfer issues and it is important to provide health management of power electronics embedded in wind systems.