Switching Power Losses Research Articles

Performance comparison of switching losses of SiC DMOS vs Si IGBT

Silicon Carbide Double Diffused Metal Oxide Semiconductor (SiC-DMOS), having a more comprehensive bandgap, fast switching and low power losses, has been rapidly developed and applied. This paper elaborates a detailed analysis of switching losses by comparing Si IGBT and SiC DMOS under the same voltage parameters and identical conditions. The switch’s characteristics are evaluated and contrasted in various gate resistances. In addition, a gate driver is designed to calculate the switching losses of IGBT and SiC DMOS at different frequencies. Then they are respectively used in the buck converter. The experimental platform is built to test and validate that the SiC DMOS buck converter achieves faster dynamic performance and higher efficiency than Si IGBT.

Power Loss and Thermal Impedance Modeling of Multilevel Power Converter With Discontinuous Modulation

The hard switching operation of the insulated gate bipolar transistor (IGBT)-based multilevel converters (MLCs) in the transformer less direct integration of renewable power plants produces a considerable amount of switching and conduction power loss. This eventually causes higher junction temperature and lower thermal stability. The symmetrically designed MLC using third harmonic sixty-degree bus-clamped pulse width modulation (BCPWM) technique demonstrates reduced switching losses and better harmonic spectra. However, the development of analytical power loss model is a complex and challenging issue due to the discontinuous switching mode of IGBTs for the BCPWM in MLC. In this regard, an analytical model for calculating the average and the rms currents for the hard switching operation of IGBTs and antiparallel diodes (APDs) with BCPWM is proposed. Furthermore, to calculate the device turn-on and turn-off losses, a discrete form of equation is presented to evaluate the transition times of switching more precisely. The numerical power loss values of IGBTs and APDs found from the derived analytical equations for MLC are compared with the simulation and experimental results. The numerical results agree well with the simulated and the experimental outcomes, which validate the proposed analytical loss model. Moreover, an advanced three dimensional thermal impedance model with chip-wise interdependent multilayer thermal coupling effect is also considered in this paper to realize the critical thermal loading condition of the switching devices.

Аналіз процесів у перетворювачі з дванадцятизонним регулюванням напруги і електромеханічним навантаженням

The article focuses on electromagnetic processes in the electric circuits withsemiconductor switches. The mathematical model of the converter with twelve-zone regulation of output voltage has been developed to analyse electromagnetic processes in semiconductor converters with pulse-width regulation. The graphs representing electromagnetic processes in electric circuits are given. The mathematical model of the semiconductor converter is also used to research transients in semiconductor converters with active inductive load. The method of multiparameter functions, which are the parts of algorithmic equations of the analysis of steady-state and transient processes inbranchy electric circuits with semiconductor switches and reactive elements, has been developed in terms of considering the features of using phase and linear voltages of the power supply network. The authors have created a new mathematical model of steadystate and transient processes in electric circuits of modulating semiconductor converters with multichannel zonal usage of phase voltages in three-phase power supply without taking into account electric power losses in switches to evaluate rapidly the influence of load parameters on the characteristics of regulated sinusoidal and DC voltages. The results of this work can be used to improve the method of multiparameter modulatingfunctions to simplify the analysis of transient processes in electric circuits without taking into account the losses in key elements. Ref. 4, pic. 3

Understanding Turn-On Transients of SiC High-Power Modules: Drain-Source Voltage Plateau Characteristics

The SiC (silicon carbide) high-power module has great potential to replace the IGBT (insulated gate bipolar transistor) power module in high-frequency and high-power applications, due to the superior properties of fast switching and low power loss, however, when the SiC high-power module operates under inappropriate conditions, the advantages of the SiC high-power module will be probably eliminated. In this paper, four kinds of SiC high-power modules are fabricated to investigate fast switching performance. The variations in characteristics of drain-source voltage at turn-on transient under the combined conditions of multiple factors are studied. A characteristic of voltage plateau is observed from the drain-source voltage waveform at turn-on transient in the experiments, and the characteristic is reproduced by simulation. The mechanism behind the voltage plateau is studied, and it is revealed that the characteristic of drain-source voltage plateau is a reflection of the miller plateau effect of gate-source voltage on drain-source voltage under the combined conditions of fast turn-on speed and low DC bus voltage, while the different values of drain-source voltage plateau are attributed to the discrepancy of structure between upper-side and lower-side in the corresponding partial path of the drain circuit loop inside the module, with the standard 62 mm package outline.

Measuring the power conversion losses in voltage source inverters

The power losses in a voltage source inverter (VSI) are the sum of the additional constant power losses of the local power supply, the inverter circuits as well as the main power conversion losses. Power conversion losses consist of the power losses on switches (e.g. static power losses on the resistances of the switches in the “on state” and the dynamic switching power losses), the power losses on the serial resistances of the filter inductor winding together with the resistances of all of the serial inverter connections and the power losses of the filter coil, which are dependent on the material of the filter coil core. All of these power conversion losses can be presented as losses on the one equivalent serial resistance that is connected serially with the filter coil. This nonlinear (depending on the load and the switching frequency) serial equivalent resistance Rse can be calculated from the parameters of the maximum point of the measured magnitude Bode plot of the control transfer function of the inverter. The paper presents the concept of measuring the Bode plots of the control transfer function in order to get the serial equivalent resistance and to calculate the power conversion losses of an experimental model and discusses the accuracy of the results.

A new three-phase multilevel DC-link inverter topology with reduced switch count for photovoltaic applications

PurposeThis paper aims to propose a new MLI topology with reduced number of switches for photovoltaic applications. Multilevel inverters (MLIs) have been found to be prospective for renewable energy applications like photovoltaic cell, as they produce output voltage from numerous separate DC sources or capacitor banks with reduced total harmonic distortion (THD) because of a staircase like waveform. However, they endure from serious setbacks including larger number of capacitors, isolated DC sources, associated gate drivers and increased control difficulty for higher number of voltage levels.Design/methodology/approachThis paper proposes a new three-phase multilevel DC-link inverter topology overpowering the previously mentioned problems. The proposed topology is designed for five and seven levels in Matlab/Simulink with gating pulse using multicarrier pulse width modulation. The hardware results are shown for a five-level MLI to witness the viability of the proposed MLI for medium voltage applications.FindingsThe comparison of the proposed topology with other conventional and other topologies in terms of switch count, DC sources and power loss has been made in this paper. The reduction of switches in proposed topology results in reduced power loss. The simulation and hardware show that the output voltage yields a very close sinusoidal voltage and lesser THD.Originality/valueThe proposed topology can be extended for any level of output voltage which is helpful for sustainable source application.

Modified DPWM Method for Vienna Rectifier Considering Current Harmonic Distortions Reduction and Neutral Point Potential Balance

A Vienna rectifier has been widely applied when power density is a design objective and usually works with a high switching frequency. Therefore, it is necessary to decrease the switching loss to reduce the temperature of the device. Discontinuous pulse width modulation (DPWM) is able to reduce the switching loss of power of the device. However, the five‐stage vector synthesis method of DPWM will increase the current harmonics. To reduce the current harmonic distortions caused by the DPWM method and reduce the switching loss of a Vienna rectifier, a modified DPWM modulation method with minimum switching loss for a Vienna rectifier is proposed in this paper, and the reduction of current harmonic is achieved by injecting the optimal zero‐sequence component into three‐phase modulation waves in the subsectors at the large‐sector transitional area. Furthermore, the three‐level topology has a problem of unbalanced neutral point potential. By changing the clamp mode in each subsector leading to different currents, leading to the neutral point, the neutral point potential is balanced. Finally, all these proposed modulation and control strategies are verified by simulation and experiment results. © 2020 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

Design, analysis and experimental verification of a high voltage gain and high‐efficiency DC–DC converter for photovoltaic applications

With the rapid development of photovoltaic systems, high step-up dc–dc converters draw significant attention, which shows the design challenges for simple topology, high efficiency, reduce voltage stress, and long lifespan. This study proposes a new high voltage gain converter that utilises the primary boost conversion cell and integrates with both switched-capacitor and coupled-inductor techniques. The proposed topology is modular and extendable for ultra-high step-up voltage gain. The leakage energy is recycled by a clamp circuit to minimise the switch voltage stress and power loss. One distinctive feature is that the voltage stress on the diodes and switch becomes low as well as constant against the variation of the duty cycle. Furthermore, the coupled inductor alleviates the diodes reverse recovery losses. The steady-state analyses, operation principles, and design guidelines are presented comprehensively. A prototype circuit is constructed to test the maximum power point tracking operation with voltage conversion from 30 to 380 V at 300 W. Experimental results substantiate the theoretical analysis and claimed advantages. The proposed converter demonstrates maximum power point tracking capability and high conversion efficiency over a wide range of power. The prototype shows the weighted efficiency of 96.3% according to the EU standard.

Reduction of Switching Power Losses for ZVS Operation in Switched-Capacitor-Based Resonant Converters

This article proposes a new method for the switched-capacitor-based resonant converter (SCRC) consisting of two-half bridge circuits and a series resonant circuit. The proposed method controls the switching frequency, phase-shift angle, and deadtime to turn the MOSFETs off with a minimum turn-off current and to turn them on with zero voltage, resulting in the reduction of the switching power losses under both light and heavy load conditions. The gate signals for the two half-bridge circuits are mathematically derived based on the electrical charge and/or energy stored in the switched capacitor and the resonant inductor. The experimental results obtained from a 3-kW, 350-kHz SCRC prototype showed that the proposed method exhibited a high maximum power conversion efficiency of 99.5%, and it maintained a proper zero-voltage switching operation at a wide output current range from 17% to 100% with a conversion efficiency higher than 98.8%.

Dodecagonal Voltage Space Vector Based PWM Techniques for Switching Loss Reduction in a Dual Inverter Fed Induction Motor Drive

The dodecagonal space vector generation scheme eliminates the most dominant lower order harmonics fifth and seventh for the entire modulation range, thereby improving the quality of the output waveform and eliminates the sixth harmonic torque pulsations. By considering this advantage, a group of dodecagonal space vector pulsewidth modulation (PWM) techniques is proposed in this article. These techniques improve the harmonic profile of the output waveform further at higher modulation indices compared to conventional dodecagonal space vector PWM. In this article, a generalized closed-form expression for harmonic distortion of various dodecagonal space vector PWM schemes is derived and the analytical results are compared. The proposed PWM techniques are simulated in MATLAB/Simulink environment and validated experimentally on a laboratory prototype. Also, a detailed switching loss analysis for various dodecagonal space vector PWM schemes are obtained and it is shown that the proposed PWM techniques yield lower inverter switching power losses than the conventional scheme throughout the power factor range.

A 20 MHz On-Chip All-NMOS 3-Level DC–DC Converter With Interception Coupling Dead-Time Control and 3-Switch Bootstrap Gate Driver

In mobile applications, power density highly affects mobility, cost, form factor, and battery time. To improve power density, high switching frequency operation is highly desirable for a power converter. However, with high switching frequency, switching power loss increases significantly, compromising efficiency and battery time. This article presents an on-chip 3-level DC-DC converter, using all NMOS devices as power switches, which reduces switching power loss and silicon cost. To facilitate the all-NMOS power stage operation and enhance the robustness to input supply variation, a 3-switch boost-strap gate driver is designed. Meanwhile, an interception coupling dead-time (ICDT) control is introduced to minimize dead-time related power loss. An integrated circuit prototype was fabricated using a 0.35 μm CMOS process. Robustly working with a variable input voltage from 3 to 6 V, it regulates a programmable power output from 0.4 to 1.6 V, with a maximum power efficiency of 85.5% over a full power range of 800 mW and a maximum power density of 1.07 W/mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . Thanks to the ICDT control, it achieves a 0.5 ns dead-time over a full-load range of 500 mA.

Real-Time Selective Harmonic Mitigation Technique for Power Converters Based on the Exchange Market Algorithm

Hand-in-hand with the smart-grid paradigm development, power converters used in high-power applications are facing important challenges related to efficiency and power quality. To overcome these issues, the pre-programmed Pulse-Width Modulation (PWM) methods have been extensively applied to reduce the harmonic distortion with very low power switching losses for high-power converters. Among the pre-programmed PWM techniques, Selective Harmonic Elimination (SHE) has been the prevailing solution, but recently, Selective Harmonic Mitigation (SHM) stands as a superior alternative to provide further control of the harmonic spectrum with similar losses. However, the large computational burden required by the SHM method to find a solution confines it as an off-line application, where the switching set valid solutions are pre-computed and stored in a memory. In this paper, for the first time, a real-time implementation of SHM using an off-the-shelf mid-range microcontroller is presented and tested. The Exchange Market Algorithm (EMA), initially focused on optimizing financial transactions, is considered and executed to achieve the SHM targets. The performance of the EMA-based SHM is presented showing experimental results considering a reduced number of switching angles applied to a specific three-level converter, but the method can be extrapolated to any other three-level converter topology.

A High Efficiency and Fast Transient Digital Low-Dropout Regulator With the Burst Mode Corresponding to the Power-Saving Modes of DC–DC Switching Converters

The proposed digital low-dropout regulator uses nonlinear switching control (NLSC) technique to suppress voltage ripple to less than 6 mV when the switching noise voltage of a switching regulator operating in a power-saving mode is greater than 50 mV. In addition, the NLSC technique improves the current efficiency by reducing the quiescent current to less than 10 μ A and reduces the switching power loss through variable switching frequency control. With a load step of 1–20 mA, the transient response time is 1.3 μ s and the peak current efficiency is 99.8% at heavy loads.

Adaptive Nonlinear Control of Three-Phase Series Active Power Filters with Magnetic Saturation

The problem of controlling three-phase series active power filters (series APF) is addressed in the presence of nonlinear loads. In previous works, the control design for series APF is generally based on standard models that assume the involved magnetic coil to be linear. In reality, the magnetic characteristics of these components are nonlinear. In this paper, a new model for series APF load system, taking into account for the nonlinearity of coil characteristics, is developed. Based on the new model, a nonlinear adaptive controller is developed, using the backstepping design. The control objectives is twofold: (i) compensating for the harmonic and disturbed voltages components at the point of common coupling, this objective is referred to network voltage quality; and (ii) regulating the inverter DC capacitor voltage. Moreover, the controller is made adaptive for compensating the uncertainty on the switching loss power. The performances of the proposed adaptive controller are formally analyzed using tools from the Lyapunov stability and average theory. The supremacy of the proposed controller with respect to standard control solution is illustrated through simulation.

The three-phase resonant DC link inverter with soft-switching function

ABSTRACT In order to realise the energy-saving operation of the three-phase inverter, a three-phase resonant DC link inverter with soft-switching function is proposed. The auxiliary resonant circuit on the DC side participates in the commutation process, so that the DC link voltage can change to zero before the main switch on the bridge arm is switched. Therefore, the main switch can complete the zero-voltage soft-switching and realise the energy-saving operation of the inverter by reducing the switching power loss. The circuit workflow and parameter design rules in each switching period are analysed. As indicated from the experimental results, the switching device is in the soft-switching state when it is switched, and when the output power reaches the rated value of 2.5 kW, the efficiency of the prototype is 98.4%, which is higher than that of the same type of soft-switching inverters. Thus, the auxiliary resonant circuit structure has reference value for the research and development of energy-saving three-phase inverters.

АНАЛІЗ ПРОЦЕСІВ У КОЛАХ ІЗ ПЕРЕТВОРЮВАЧАМИ ТРИФАЗНОЇ НАПРУГИ В ПОСТІЙНУ З ДВАНАДЦЯТИЗОННИМ РЕГУЛЮВАННЯМ НАПРУГИ

Urgency of the research. Due to the widespread use of semiconductor switches in the electrical circuits of modern converters of electricity parameters, the tasks of analysis of electromagnetic processes are significantly complicated. The greatest complications arise when it is necessary to model steady-state and transient processes in branched circuits of variable structure, in which links with reactive elements sinusoidal, constant and pulse voltages occur. Target setting. The mathematical model of the converter can be built using the method of multiparameter modulating functions in the direction of developing new mathematical models of electromagnetic processes in circuits with semiconductor switches and links of sinusoidal, direct and pulsed currents. Actual scientific researches and issues analysis. In the publications of M. Makarenko, V. Senko, N. Yurchenko, А. Scherba and other scientists have developed a method of multiparameter functions that simplifies the evaluation of electromagnetic processes in sinusoidal current circuits with semiconductor switches. Uninvestigated parts of general matters defining. There is a need to develop a multiparameter method for the analysis of transients in electrical circuits with links not only sinusoidal, but also direct and pulsed currents required for the implementation of electromechanical and discharge-pulse technologies. The research objective. Creation of a mathematical model for the analysis of electromagnetic processes in a semiconductor converter with multiband regulation of the output voltage when connecting the phase voltages of the power supply network. The statement of basic materials. The article analyzes the electromagnetic processes in electrical circuits with semiconductor switches. A mathematical model for the analysis of electromagnetic processes in semiconductor converters with pulsewidth regulation of the output voltage is created. Conclusions. A new mathematical model for the analysis of electromagnetic processes in electric circuits of semiconductor converters of modulation type with multichannel band use of phase voltages of three-phase power supply network without taking into account power losses in switches is developed.

Optimum pulse-width modulation strategy for a symmetric cascaded multilevel inverter

This paper investigates for the most suitable PWM strategy for a symmetric cascaded multilevel inverter. The objective is to determine a PWM switching strategy which optimises inverter performance by ensuring higher DC link utilisation and minimum total harmonic distortion (THD) at low switching frequency to minimise switching power losses. Simulations carried out in MATLAB-Simulink environment has given an insight of inverter performance when carrier-based PWM techniques are applied. In this parametric evaluation, both odd and even multiples of 50 Hz modulating signal were applied for obtaining switching frequency for various multicarrier-based PWM strategies.

Design and simulation full control strategy in single-phase five-level inverter

A five-level inverter has been used for many applications in renewable energy systems. In terms of harmonic distortion is lower compared to conventional two-level inverters. The five-level converter has several disadvantages such as the number of semiconductor power switches, pulse width modulation control methods, and the semiconductor switch power loss. This paper aims to propose a new control strategy and design on a five-level inverter. Unipolar control strategy modulation of sinusoidal pulse width modulation is used for each power semiconductor switch. This converter only requires 2 carrier signals and is simulated in real-time with a THD of 3.36%.

Design of closed-loop control for Solar PV based Multi-Level Inverter

Photovoltaic (PV) based multilevel inverters (MLI) have emerged as one of the best alternatives for grid/standalone applications. MLIs offer high range power handling capability with low current and voltage distortion and lesser switching losses as compare to the traditional two-level inverter. Major challenges with generally used multilevel inverter topologies relates to capacitor voltage variation, modulation techniques, and control. The major center of attention of research in this paper is to build up sophisticated modulation and voltage balancing methods for multilevel inverter topologies, competent to reach capacitor voltage parameter and to decrease power switching losses of the inverters. The present paper focuses on closed-loop control of multilevel flying capacitor inverter (FCI). In FCI, the phase shift (PS) based pulse width modulation method is designed and investigated. The closed-loop controller is designed with input voltage control of MLI, whose source is solar PV based Boost converter. Reported simulation results prove the superiority of the closed loop control in maintaining the desired output voltage for various reference values.

Дослідження електромагнітних процесів у перетворювачі з тризонним регулюванням напруги

The article focuses on electromagnetic processes in electric circuits with semiconductor switches. A mathematical model of a semiconductor converter with three-zone output voltage control has been created so as to analyse electromagnetic processes in semiconductor converters with pulsewidth control. The graphs showing electromagnetic processes in electric circuits are given. The mathematical model of the semiconductor converter is also used to study transients in semiconductor converters with actively-inductive load. The method of multiparameter functions, which are included in the algorithmic equations to analyse steady-state and transient processes in branchy circuits with semiconductor switches and reactive elements, has been improved by using the peculiarities of phase and linear voltages in the power supply grid. We have developed a new mathematical model of steadystate and transient processes in electric circuits of semiconductor converters of modulation type with multichannel zone usage of phase voltages of a three-phase power supply system without considering power losses in switches to quickly evaluate the influence of load parameters on the regulated sine and constant voltages. The results of this work can be used to develop the method of multiparameter modulating functions to simplify the analysis of transients in electrical circuits without taking into account the losses in key elements.Ref. 4, pic. 3