Thermal-Powerloss Approximation Method for Determination of Efficiency in Semiconductor Devices

A number of the circuit and design decisions that provide a reduction in overvoltage and dynamic power losses in power switches of multilevel voltage inverters with clamping diodes is considered. It is shown that the integral or unpackaged version is the most effective method for a reduction in the stray inductance in the multilevel circuit, which is the general cause for occurrence of dynamic overvoltage. To reduce dynamic losses of power, a method for resonant commutation on fronts, which provides commutation of switches in the multilevel circuit at zero voltage (SZV) and zero current (SZC), is proposed. The resonant switching method as applied to the multilevel circuit simultaneously solves a problem of dynamic overvoltage by means of limitation for the rate of voltage rise in the SZV mode or the mode of preliminary fault of energy stored in the inductance of the switching circuit in the SZC mode.

Voltage source inverter (VSI) is one of the most common types of power converters, which is used in various industries. The energy efficiency indicators of the AVI depend not only on the IGBT or MOSFET-based transistors used in the AVI element, but also on the chosen modulation algorithm.The most commonly used in VSI is pulse width modulation (PWM) and single modulation. The advantage of PWM prior to single modulation is the ability to control the amplitude of the first harmonic of the output voltage and, accordingly, the current required both for scalar and vector control of an asynchronous electric drive.At the same time, the disadvantage of PWM is the need for a higher switching frequency of power switches, which results in higher dynamic losses. In addition, in the PWM mode, VSI at the same load parameters has a smaller amplitude of the first harmonic of the output voltage, and hence less output power.The article proposes the use the mode of overmodulation algorithm in the pulse-width modulation (PWM) mode for a three-level autonomous voltage inverter, which is relatively classical PWM with a modulation factor equal to one, justified and allows to increase the control range of the output power of the VSI, to reduce the dynamic losses in the power switches, to improve the sinusoidal output current, as well as reduce the ripple factor of the input current. Given the dependence of the energy indicators of the VSI on the modulation factor in the mode of overmodulation.In the specialized MelcoSim program from Mitsubishi, the calculation of static and dynamic losses in the power switches of an autonomous voltage inverter in the mode of overmodulation was performed. The dependences of the output power on the modulation coefficient, the dependence of the amplitude of the first harmonic of the output current on the modulation coefficient, the dependence of the coefficient of harmonic distortion of the output voltage on the modulation coefficient, the dependence of the harmonic distortion factor of the output current on the modulation coefficient, and the dependence of the losses in the power switches on the modulation coefficient.

The dynamic losses in fast ramped super ferric magnets will create the main part of the expected heat losses in the superconducting synchrotron SIS100 – the primary accelerator in the Facility for Antiproton and Ion Research (FAIR). The data measured on dipole models at the cryogenic magnet test facility at GSI allow to predict the static and dynamic losses in the superconducting magnets for different operation modes of the SIS100 synchrotron. The calculations of the expected mass flow rates in the cooling channels of the superconducting magnets together with the analysis of the cooling system for different operation modes of the synchrotron will be presented.

This paper presents the correlation of factors that determine the quality of asymmetric quasi-sinusoidal output current and dynamic losses in the switches of the current generator circuit. The operating mode of the generator was obtained, especially of its power circuit elements, where combination of acceptable output current quality with relatively small dynamic losses in switches and mass-dimensional parameters of the inductor are provided. Achieved results can be used in designing this type of generators.

This paper presents the experimental evaluation of a flux linkage-based inverter loss model embedded in a deadbeat-direct torque and flux control (DB-DTFC) that achieves desired torque and minimizes losses over each switching period. The optimal flux commands are selected from those that will achieve the desired torque by using embedded dynamic flux linkage-based loss models of the machine and inverter. The proposed inverter loss model is implemented in real-time on a flux weakening interior permanent magnet synchronous machine (FW-IPMSM) test bench and evaluated experimentally. The actual inverter losses are obtained by measuring the electrical power at three different points in the test bench. In order to evaluate the loss model, comparative evaluation of the actual inverter losses versus the estimated losses have been performed under both constant stator flux and dynamic flux trajectories. Finally, losses resulting from using different widely used loss minimizing control strategies are compared.

The operation of a push-pull converter with an input choke and an autotransformer current divider operating in the soft switching mode of all transistors, which is provided by reversing the instantaneous value of the inductor current, is considered. The implementation of the soft switching condition of all transistors, except for reducing dynamic losses on them, leads to an in-crease in dynamic losses in the inductor and static losses in the circuit due to an increase in the effective value of the inductor current. As a result of the experiment, it was shown that an increase in the variable component of the inductor current leads to an increase in the converter efficiency to a certain level of the average inductor current.

A comparison of different power electron switches for power electron converters is presented. The estimation method of steady and dynamic power loss in the switches is also described.

In this paper, a comprehensive study is conducted on AlGaN/GaN FinFETs as a potential candidate for microwave and power applications. It has been described that due to superior material properties associated with GaN and electrical properties exhibited by the tri-gate structure, FinFETs offer superior results for radio frequency applications. The tri-gate structure of FinFET allows full depletion of the channel, which results in low leakage current and dynamic power loss. FinFETs offer higher current density and integration compared to other mainstream CMOS technologies.

This study proposes an integrated eco‐driving controller, in which speed profile and power split optimisation are simultaneously treated. A speed profile controller is designed based on a multi‐phase dynamic programming (DP) algorithm, which is utilised to optimise speed trajectories with the detailed model of the traction power system, vehicle dynamics system, and signal constraints at intersections. The optimised speed and demand power profiles are designed as the reference of the power split optimal controller. A DP algorithm is presented to determine voltage trajectories of supercapacitors with power plant voltage limitations and dynamic power losses. The performance of the proposed integrated method is evaluated by numerical simulation based on an actual route of Chengdu Tramway Line 2. The energy reduction can be achieved by the speed profiles controller, compared to the eco‐cruising benchmark strategies. Energy efficiency can be further improved by the integrated eco‐driving controller. Moreover, the influences of green signal time windows and trip time on the shape of the optimised solution are investigated. For a given journey, the trip time with minimum energy consumption can be obtained. The integrated eco‐driving control method can be implemented by driver assistant systems or automatic train operation systems.

The operation of photovoltaic systems depends on the environmental conditions, which affect the current-voltage characteristics of photovoltaic modules and more complex structures. Under non-uniform environmental conditions - different illumination of cells within one module - the characteristics of the module can be increasingly complex. Safety bypass diodes, which are connected in parallel with the cells and protect them from overheating during partial shading, also contribute to this complexity. In order to evaluate the performance of the photovoltaic system, specifically the inverter and the algorithm for maximum power point tracking, it is necessary to take into account these influences on the characteristics of the photovoltaic structures. In this manuscript, the influence of illumination and temperature on individual photovoltaic cells, the topology of a photovoltaic module including bypass diodes, as well as the characteristics of modules with protective bypass diodes under non-uniform environmental conditions are discussed.

The introduction of next generation mobile systems and alternative applications demands significant improvement in efficiency and linearity of the power amplifier. It is essential to understand the limitations inherent to the power transistor, and improve it for emerging applications. The package containing the power transistor is built up of various components; MOS capacitors, bond wire arrays and ESD protection circuitry common in commercial power transistors in addition to the semiconductor transistor die. The objectives of this work are to develop multiphysics modelling components which are needed for CAD-based design optimisation. An electrothermal bond wire array model is proposed which combines the electrical and thermal characteristics at high-frequency, reproducing the non-uniform distribution seen in measurements. The model returns the temperature distribution over 2000-times faster, in a fraction of a second, compared to an equivalent 3D multiphysics simulation which takes at least 23 minutes, making it well suited to circuit modelling for CAD-design and optimisation. Fundamentally, the foundations of the power transistor is the semiconductor technology that the package holds. Extraction of compact transistor models is time consuming, requiring a multitude of measurement steps and specialised equipment. Behavioural modelling techniques simplify the measurement extraction procedure, while conserving the accuracy and convergence needed for circuit modelling. A primary limiting factor of the X-parameter behavioural model is that it lacks thermal memory effects that are prevalent in most applicable transistor technologies. This work extends the extraction of X-parameters to include dynamic thermal memory effects. Thermal hysteresis is demonstrated and shown to introduce spectral asymmetry during simulations using two-tone and QAM-16 modulation stimulus. Furthermore, distributed multiphysics modelling techniques co-simulate electromagnetics, thermodynamics and semiconductor device physics - the coupled solution providing enhanced insight into the performance and limitations of the transistor compared to lumped modelling approaches. A distributed electrothermal model was developed which enables significant design improvements by optimisation of the thermal and electrical layouts. This is demonstrated at 28~GHz for a GaN pHEMT transistor where a 12% increase in linear output power and 54% increase in PAE is achieved relative to the peak efficiency of the transistor (24%). The multiphysics modelling components developed in this work aim to improve power transistors for next generation mobile systems and applications requiring the efficient application of high-power microwaves.

The main theme of this paper is to propose a novel switching control method for bridgeless PFC converter to improve the efficiency by reducing both switching and conduction losses. Comparing to the conventional method, the power device is always on (no switching loss) to provide a current path via the turn-on resistor of MOSFET to reduce conduction losses under light load condition. As the load increases, the power device is always off (no switching loss) to provide a current path via the body diode of MOSFET to reduce conduction losses under heavy load condition. In this paper, both simulation and experimental results will be shown to confirm the effectiveness of the proposed switching control method. Test results derived from a digital-controlled 1.2 kW PFC show the efficiency improvement can go up to 0.73% and 0.57% under full load and light load conditions, respectively. It will also be confirmed this efficiency improvement has no impact on the power factor and just simply changing the switching control method. Both measured steady state and transient waveforms will be shown for confirmation.

Improving the energy efficiency of vehicles is an essential feature of scientific and technical progress. One means of increasing the energy efficiency of transport is the introduction of electric drive with multiphase induction motors. At the same time multiphase motors are fed by multiphase frequency converters based on voltage source inverters. The number and operating mode of power switches in multiphase frequency converters may differ from the traditionally accepted in the three-phase converter. The article presents a comparative assessment of losses in three phase and 79-phase frequency converters based on the calculation of static and dynamic losses in the switches of voltage source inverters, the output voltage of which is formed under the law of sinusoidal pulse width modulation and the basic law of switching

This paper presents the experimental characteristics of a high voltage IGBT and diode chip set designed for safe operation under hard switching conditions at the 2.8 kV DC link level. The fundamental goal of the design is a low cosmic ray induced failure rate for diodes as well as IGBTs at the DC link level. At the same time all the common requirements of low static and dynamic losses as well as wide SOA under turn-off, reverse recovery and short-circuit conditions are fulfilled. The blocking capability of these devices exceeds 4.5 kV by far.

This paper presents a practical (experimental) and theoretical (through simulation) approach of a prototype of full-bridge DC-DC power converter driven under a hard-switching control algorithm modeled in the MATLAB / Simulink software environment and compiled on a dSPACE control hardware. The experimental approach involves the use of new-generation power modules with semiconductor components made of silicon carbide (SiC). Starting from the preliminary gathered experimental data and from the acquired waveforms, which expose the operating behavior of the proposed converter design at different switching frequencies and loads, an equivalent model of the experimental assembly was built in the MATLAB / Simulink software environment. Based on parallel investigations (practical and theoretical), this paper responds whether the preliminary performance of the converter is satisfactory, so that it can be further used as a charging module in (fixed or mobile) charging systems and supply systems for (partially or fully) electric vehicles. Also, it is analyzed what further improvements may be adopted so that a future designed charging module may be suitable for the conversion of energy supplied from both, conventional and unconventional energy sources.