Wide Bandgap Semiconductor Power Research Articles

A Computational Multiscale Modeling Method for Nanosilver-Sintered Joints with Stochastically Distributed Voids

A high power density is required in wide band gap power semiconductor packaging, which has led to the popularity of sintered nanosilver as an interconnecting material. However, affected by stochastically distributed voids in its microstructure, this material in practice exhibits instability leading to reduced reliability. In this paper, a computational multiscale modeling method is proposed to simulate the influence of micro-voids on macro-properties, providing an efficient tool to analyze the aforementioned problem. At the micro-scale, the three-parameter Weibull distribution of the equivalent Young’s modulus and the normal distribution of the equivalent Poisson’s ratio are captured by Monte Carlo-based finite element simulation on the reconstructed stochastic representative elements, where the density and distribution morphology of micro-voids are taken into consideration. At the macro-scale, the effect of the microscopic voids is transferred through a random sampling process to construct the multiscale model. The effectiveness and validity of the proposed method are verified through experimental case studies involving the modeling of nanosilver-sintered joints sintered at temperatures of 275°C and 300°C. In addition, the effects of the sintering temperature on the dispersion of the micro-voids, the distribution fluctuation of the constitutive parameters, and the mechanical properties are also discussed based on numerical and experimental results.Graphical

Ultrasonic-enhanced silver‑indium transient liquid phase bonding in advancing rapid and low-temperature packaging

Transient liquid phase (TLP) bonding technique is one of the promising solutions to third-generation wide-bandgap semiconductor power packaging. However, its prolonged heating process of the components restricts its application to some extent. To address this issue, the singular impact of acoustic cavitation induced by ultrasound emerges as a promising solution. For the first time, this study proposes the incorporation of ultrasound into the silver‑indium (Ag-In) TLP bonding process, enabling rapid and efficient bonding with 50 μm interlayers within seconds, while achieving a maximum shear strength of 60 MPa. A comprehensive comparative and analytical investigation of the interfacial microstructure, mechanical properties, and grain distribution has been carried out, in comparison to that of the conventional Ag-In TLP joint. The overall temperature profile was monitored utilizing a non-contact infrared camera and subsequently corroborated with finite element simulation outcomes. The phase analysis unveiled a predominant composition of the solid solution phase (Ag)-In within the bonding region, which contributes to a pronounced enhancement of the mechanical properties of the joints. Transmission electron microscopy (TEM) confirmed the complete degradation of the initial bonding interface, resulting in a bond with a bulk-like appearance. Finally, this work has elucidated the underlying mechanisms for the ultrasonic-enhanced transient liquid phase bonding (U-TLP) joint formation, where the influence of acoustic cavitation on element diffusion and the metallurgical bonding process has been discussed.

A Comprehensive Review on the Power Supply System of Hydrogen Production Electrolyzers for Future Integrated Energy Systems

Hydrogen energy is regarded as an ideal solution for addressing climate change issues and an indispensable part of future integrated energy systems. The most environmentally friendly hydrogen production method remains water electrolysis, where the electrolyzer constructs the physical interface between electrical energy and hydrogen energy. However, few articles have reviewed the electrolyzer from the perspective of power supply topology and control. This review is the first to discuss the positioning of the electrolyzer power supply in the future integrated energy system. The electrolyzer is reviewed from the perspective of the electrolysis method, the market, and the electrical interface modelling, reflecting the requirement of the electrolyzer for power supply. Various electrolyzer power supply topologies are studied and reviewed. Although the most widely used topology in the current hydrogen production industry is still single-stage AC/DC, the interleaved parallel LLC topology constructed by wideband gap power semiconductors and controlled by the zero-voltage switching algorithm has broad application prospects because of its advantages of high power density, high efficiency, fault tolerance, and low current ripple. Taking into account the development trend of the EL power supply, a hierarchical control framework is proposed as it can manage the operation performance of the power supply itself, the electrolyzer, the hydrogen energy domain, and the entire integrated energy system.

Examining the Optimal Use of WBG Devices in Induction Cookers

Modern induction cookers have started to demand challenging features such as slim design, high power ratings, high performance, and silence. All those requirements are directly related to the power semiconductors used in power converters. Si (silicon)-based power semiconductors are not capable of answering those demands because of strict operating conditions, such as high ambient temperatures. Therefore, WBG (Wide Band Gap) power semiconductors have been getting attention. In this study, WBG power semiconductors will be compared with Si-based IGBT (Insulated Gate Bipolar Transistor) under different operating conditions. The best option to use WBG power semiconductors in modern induction cookers will be analyzed. The performance of a series-resonant half-bridge converter was evaluated under various operating conditions. Measurements were obtained from the real operating conditions of induction hobs. The switching frequency is changed from 20 kHz to 100 kHz, while the power rating is increased to 3.7 kW. In addition to traditional 4-zone induction cooktops, this discussion also provides a comprehensive analysis of high-segment, fully flexible induction cooktops. While the IGBT-based design exhibits 25.79 W power loss per device, the WBG device exhibits 6.87 W in the maximum power condition of conventional induction cooker operation. When it comes to high-frequency operation, the WBG power device exhibits 10.05 W at 95 kHz. Total power loss is still well below that of the IGBT-based conventional design. Appropriate usage of WBG power semiconductors in modern induction cookers can exploit many more benefits than Si-based designs.

Power Electronics Revolutionized: A Comprehensive Analysis of Emerging Wide and Ultrawide Bandgap Devices.

This article provides a comprehensive review of wide and ultrawide bandgap power electronic semiconductor devices, comparing silicon (Si), silicon carbide (SiC), gallium nitride (GaN), and the emerging device diamond technology. Key parameters examined include bandgap, critical electric field, electron mobility, voltage/current ratings, switching frequency, and device packaging. The historical evolution of each material is traced from early research devices to current commercial offerings. Significant focus is given to SiC and GaN as they are now actively competing with Si devices in the market, enabled by their higher bandgaps. The paper details advancements in material growth, device architectures, reliability, and manufacturing that have allowed SiC and GaN adoption in electric vehicles, renewable energy, aerospace, and other applications requiring high power density, efficiency, and frequency operation. Performance enhancements over Si are quantified. However, the challenges associated with the advancements of these devices are also elaborately described: material availability, thermal management, gate drive design, electrical insulation, and electromagnetic interference. Alongside the cost reduction through improved manufacturing, material availability, thermal management, gate drive design, electrical insulation, and electromagnetic interference are critical hurdles of this technology. The review analyzes these issues and emerging solutions using advanced packaging, circuit integration, novel cooling techniques, and modeling. Overall, the manuscript provides a timely, rigorous examination of the state of the art in wide bandgap power semiconductors. It balances theoretical potential and practical limitations while assessing commercial readiness and mapping trajectories for further innovation. This article will benefit researchers and professionals advancing power electronic systems.

Experimental Study of Radiated Emission Due to Secondary Common-Mode Current in Buck Converters

High switching frequency and fast switching speed of wide bandgap power semiconductor device-based power converters may increase radiated emissions more than conventional silicon-power device-based power converters. Based on the background, this article experimentally investigates radiated emission sources in buck converters. The experimental system constructed in this article has two common-mode noise paths, the primary common-mode and the secondary common-mode. First, this article outlines that a secondary common-mode voltage source is caused by a primary common-mode current and an imbalance of power supply side impedances, and the secondary common-mode current path acts as a monopole antenna. The common-mode currents and the radiated emissions are measured in an anechoic chamber when the common-mode inductor for each mode is connected. The measurement results show that the primary common-mode current generates the secondary common-mode noise, and the secondary common-mode noise is the dominant source of radiated emission in the experimental system.

Technology and Applications of Wide Bandgap Semiconductor Materials: Current State and Future Trends

Silicon (Si)-based semiconductor devices have long dominated the power electronics industry and are used in almost every application involving power conversion. Examples of these include metal-oxide-semiconductor field-effect transistors (MOSFETs), insulated-gate bipolar transistors (IGBTs), gate turn-off (GTO), thyristors, and bipolar junction transistor (BJTs). However, for many applications, power device requirements such as higher blocking voltage capability, higher switching frequencies, lower switching losses, higher temperature withstand, higher power density in power converters, and enhanced efficiency and reliability have reached a stage where the present Si-based power devices cannot cope with the growing demand and would usually require large, costly cooling systems and output filters to meet the requirements of the application. Wide bandgap (WBG) power semiconductor materials such as silicon carbide (SiC), gallium nitride (GaN), and diamond (Dia) have recently emerged in the commercial market, with superior material properties that promise substantial performance improvements and are expected to gradually replace the traditional Si-based devices in various power electronics applications. WBG power devices can significantly improve the efficiency of power electronic converters by reducing losses and making power conversion devices smaller in size and weight. The aim of this paper is to highlight the technical and market potential of WBG semiconductors. A detailed short-term and long-term analysis is presented in terms of cost, energy impact, size, and efficiency improvement in various applications, including motor drives, automotive, data centers, aerospace, power systems, distributed energy systems, and consumer electronics. In addition, the paper highlights the benefits of WBG semiconductors in power conversion applications by considering the current and future market trends.

A Review on Modular Converter Topologies Based on WBG Semiconductor Devices in Wind Energy Conversion Systems

This paper presents a comprehensive review on the employment of wide bandgap (WBG) semiconductor power devices in wind energy conversion systems (WECSs). Silicon-carbide- (SiC) and gallium-nitride (GaN)-based power devices are highlighted and studied in this review, focusing on their application in the wind energy system. This is due to their premium characteristics such as the operation at high switching frequency, which can reduce the switching losses, and the capability to operate at high temperatures compared with silicon (Si)-based devices. These advantages promote the replacement of the conventional Si-based devices with the WBG semiconductor devices in the new modular converter topologies due to the persistent demand for a more-efficient power converter topology with lower losses and smaller sizes. The main objective of this paper was to provide a comprehensive overview of the WBG power devices commercially available on the market and employed in the modular converter topologies for renewable energy systems. The paper also provides a comparison between the WBG power technologies and the traditional ones based on the Si devices. The paper starts from the conventional modular power converter topology circuits, and then, it discusses the opportunities for integrating the SiC and WBG devices in the modular power converters to improve and enhance the system’s performance.

Thermal Impedance Calibration for Rapid and Noninvasive Calorimetric Soft-Switching Loss Characterization

Virtual prototyping, multi-objective optimization and design automation are increasingly being used to meet the growing demands of modern power electronic applications in terms of efficiency and power density. These concepts are based on accurate loss models of the power semiconductors used. While for hard-switching the double pulse test is an established electrical characterization method, soft-switching losses can only be determined by calorimetric measurements. Despite significant improvements in using transient approaches, calorimetric characterization of soft-switching loss energy is very time-intensive and requires complex measurement setups. This paper presents a new automated calorimetric method with thermal impedance calibration that enables rapid and non-invasive switching loss measurements. Using ultra-fast transient measurements and accelerated cooling phases in between, soft-switching loss maps can be determined based on hundreds of individual readings. The proposed measuring method is validated against hard-switching electrical double pulse test measurements. The method achieves a maximum error of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$1.9 \,\%$</tex-math></inline-formula> for the total loss measurement from <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$1-9 \,\mathrm{W}$</tex-math></inline-formula> and an average measurement error of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$16.5 \,\%$</tex-math></inline-formula> for the soft-switching energy from <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$1-4 \,\mu \mathrm{J}$</tex-math></inline-formula> of wide bandgap power semiconductors. In addition to comparing the results of different semiconductor technologies for use in a charger application, the manufacturers' simulation models are also analyzed with respect to soft-switching energy.

Improved Gate-Voltage-Driven Desaturation Short-Circuit Protection Circuit With Robust Switching Noise Immunity for WBG Power Semiconductors

Wide bandgap (WBG) power semiconductors are used in numerous power conversion applications because of their excellent switching characteristics. However, it is difficult to ensure short-circuit protection for WBG power semiconductors because of their shorter short-circuit withstand time. The fast-switching characteristics of WBG power semiconductors induces severe fluctuations in the drain-source voltage and drain current in switching transients, which results in the false triggering of the protection circuit. Therefore, the fast response speed and switching noise suppression are key requirements of the protection circuit for a WBG power semiconductor. To meet these requirements, an improved gate-voltage-driven desaturation protection circuit with a fast response speed and robust noise immunity is proposed in this study. The effect of switching noise on the proposed protection circuit is analyzed, and a detailed design procedure based on the analysis results is provided. The experimental results indicate that the protection delay of the proposed circuit is within 91 ns; additionally, the proposed circuit can survive switching noise during normal operation. Finally, the noise immunity analysis results are verified through experiments under various protection circuit parameter sets.

A Comparative Evaluation of Wide-Bandgap Semiconductors for High-Performance Domestic Induction Heating

This paper presents a comparative evaluation of wide-bandgap power semiconductor devices for domestic induction heating application, which is currently a serious alternative to traditional heating techniques. In the induction heating system, the power transferred to the output depends on the equivalent resistance of the load, and the resistance depends on the operating frequency. Due to the switching characteristics of wide-bandgap power semiconductor devices, an induction heating system can be operated at higher operating frequencies. In this study, SiC and Si semiconductor devices are used in the comparison. These devices are compared according to different evaluation issues such as the turn-off energy losses, turn-off times, current fall time, the power losses of the internal diodes, and the conduction voltage drops issues. To perform the proposed evaluation, the series-resonant half-bridge inverter, which is frequently used in state-of-the-art induction heating systems, has been selected. The device suitability in an induction heating system is analyzed with the help of a test circuit. A comparison is made in terms of criteria determined by using the selected switches in the experimental circuit, which is operated in the 200 W to 1800 W power range and 45 kHz to 125 kHz switching frequency range. System efficiency is measured as 97.3% when Si IGBT is used. In the case of using SiC cascode JFET, the efficiency of the system is increased up to 99%.

Remaining Useful Lifetime Prediction Based on Extended Kalman Particle Filter for Power SiC MOSFETs.

Nowadays, the performance of silicon-based devices is almost approaching the physical limit of their materials, which have difficulty meeting the needs of modern high-power applications. The SiC MOSFET, as one of the important third-generation wide bandgap power semiconductor devices, has received extensive attention. However, numerous specific reliability issues exist for SiC MOSFETs, such as bias temperature instability, threshold voltage drift, and reduced short-circuit robustness. The remaining useful life (RUL) prediction of SiC MOSFETs has become the focus of device reliability research. In this paper, a RUL estimation method using the Extended Kalman Particle Filter (EPF) based on an on-state voltage degradation model for SiC MOSFETs is proposed. A new power cycling test platform is designed to monitor the on-state voltage of SiC MOSFETs used as the failure precursor. The experimental results show that the RUL prediction error decreases from 20.5% of the traditional Particle Filter algorithm (PF) algorithm to 11.5% of EPF with 40% data input. The life prediction accuracy is therefore improved by about 10%.

Three-Dimensional Lattice Structure to Reduce Parasitic Inductance for WBG Power Semiconductor-Based Converters

Wide bandgap (WBG) power semiconductors can achieve high efficiency and power density due to their low on-resistance and fast switching speeds. However, the fast-switching speed induces voltage to the parasitic inductance in the circuit, causing a significant overshoot in the drain-source voltage of the devices and the ringing of the drain current due to resonance with the parasitic capacitance. Thus, minimizing parasitic inductance is necessary for driving WBG power semiconductors in a stable manner. This paper proposes a three-dimensional lattice structure that reduces parasitic inductance through horizontal and vertical magnetic flux cancellations within a printed circuit board (PCB). The relationship between the magnetic flux cancellation and the parasitic inductance is analyzed, and the magnetic flux cancellation in the proposed structure is described. In addition, a practical PCB layout design procedure based on the proposed structure is provided. Simulation results demonstrate a 55.8% reduction in parasitic inductance, and experimental results show reduced overshoot and ringing at the switching transient, resulting in a 26% reduction in switching loss. As a result, the proposed method can improve the efficiency and stability of WBG device-based power converters.

Review of Topside Interconnections for Wide Bandgap Power Semiconductor Packaging

Due to their superior material properties, wide bandgap (WBG) semiconductors enable the application of power electronics at higher temperature operation, higher frequencies, and higher efficiencies compared to silicon (Si). However, the commonly-used aluminum wire bonding as topside interconnection technology prevents WBG semiconductors from reaching their full potential, due to inherent parasitic inductances, large size, heat dissipation, and reliability issues of wire bonding technology. Therefore, this article presents a comprehensive review of topside interconnection technologies of WBG semiconductor power devices and modules. First, the challenges and driving factors for the interconnection of WBG semiconductor dies are discussed. Second, for each widely commercially used WBG semiconductor, i.e., silicon carbide and gallium nitride, technical details and innovative features of state-of-the-art interconnection techniques in packages are reviewed. Then, the majority of existing topside interconnection materials for WBG semiconductors are categorized and compared, followed by a discussion of their advantages, challenges, and failure modes. Based on this elaborate discussion, potential future directions of the interconnection technology development are given. It is concluded that the superior performance of WBG semiconductors can be obtained by combining novel materials with innovative designs for the topside interconnections.

Innovative ceramic-matrix composite substrates with tunable electrical conductivity for high-power applications

ABSTRACT A wide band gap semiconductor power module can operate at higher voltages as compared with its traditional silicon counterpart. However, its insulating system undergoes stronger electric fields at the triple point between the ceramic substrate, the metallic tracks and the encapsulating polymer, which can dramatically reduce its lifespan. Here we report an original concept based on the local modification of the substrate properties to mitigate such electrical stress. Numerical simulations revealed its potential to reduce this constraint by up to 50%. This concept was realized by developing, through a practical approach, a novel substrate made of an AlN-based ceramic (material A) integrating a nanocomposite volume endowed with controlled properties and geometry. This approach implies first the spark plasma sintering of the AlN powder with additives (Y2O3, CaF2) to endow the material A with a very low electrical conductivity (σ) and high thermal conductivity (k). Graphene nanoplatelets (GNP) were incorporated within this material to fabricate a nanocomposite with a controlled σ anisotropy that otherwise reached a striking ratio of 106 at 20°C for 1.25 vol% GNP. Our approach secondly aimed at developing an effective process allowing to integrate this nanocomposite into the material A with a very high degree of reproducibility. It finally consisted in establishing the electrical contacts on the achieved substrate and encapsulating it for breakdown testing. The novel substrate enabled a mitigation of the electrical constraint by diminishing its intensity and shifting it from the triple point to a less constrained area. It already brought an improvement in breakdown voltage (VB) by 15% as compared to the traditional substrate, and revealed the potential for achieving higher VB as well. This work lays the foundation for the development of novel multifunctional ceramic-matrix composite substrates sought for power electronics as well as for other potential applications.

Survey of 99.9% Class Efficiency DC‐AC Power Conversion and Technical Issues

This study provides a survey overview of the literatures with the goal of maximizing the efficiency of DC‐AC power conversion from an engineering science perspective. With the advent of wide band gap power semiconductors, the published literature on realizing high efficiency DC‐AC converters has increased. Therefore, a literature survey of high‐efficiency DC‐AC inverters was first conducted. We demonstrated the importance of the measurement accuracy in measuring high efficiency losses, and then presented the literature on new measurement methods, as well as examples of analysis of the breakdown of these losses. Furthermore, we reviewed the literature on high‐efficiency inverters. We presented measurement data (99.83%) on an inverter with a high efficiency energy conversion system circuit topology using Silicon Carbide (SiC) and Gallium Nitride (GaN) devices to demonstrate how the procedure was used to achieve loss minimization. We summarized the challenges hindering high efficiency. © 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

(Invited) Recent Progress in Wide-Bandgap Semiconductor Devices for a More Electric Future

Wide-bandgap (WBG) semiconductors, with their excellent electrical properties, offer breakthrough performance in power electronics enabling low losses, high switching frequencies, and high temperature operation. WBG semiconductors are likely candidates to replace silicon-based semiconductors in the near future seeing as Silicon is fast approaching its performance limits for high power requirements. Wide-bandgap power semiconductor devices offer breakthrough circuit performance enabling low losses, high switching frequencies, and high temperature operation which will allow for enormous energy efficiency gains in a wide range of potential applications. In the past ten years, the U.S. Department of Energy’s Advanced Research Project Agency - Energy (ARPA-E), which was established to fund creative, out-of-the-box, transformational energy technologies that are too early for private-sector investment, has invested in WBG semiconductors including material and device-centric programs along with application specific programs targeting the barriers to widespread adoption in power electronics. Under these ARPA-E programs, medium voltage (10-20kV) WBG device development has commenced to push the voltage boundaries of the devices including the development of WBG super-junction devices. Light triggered photoconductive WBG devices are also being investigated for MV applications. The WBG MV devices will enable MVDC grid distribution applicable to markets including electrified transportation, renewable interconnections, and offshore oil, gas, and wind production. Other WBG device ideas are also being explored under ARPA-E programs including WBG integrated circuits and neutron detectors. The progress and challenges of the WBG devices being developed under ARPA-E programs will be reviewed along with thoughts on the future trends of WBG device development.

(Invited) Recent Progress in Wide-Bandgap Semiconductor Devices for a More Electric Future

Wide-bandgap (WBG) semiconductors, with their excellent electrical properties, offer breakthrough performance in power electronics enabling low losses, high switching frequencies, and high temperature operation. WBG semiconductors, such as silicon carbide and gallium nitride, are likely candidates to replace silicon in the near future for high power applications as silicon is fast approaching its performance limits. Wide-bandgap power semiconductor devices enable breakthrough circuit performance and energy efficiency gains in a wide range of potential applications. The U.S. Department of Energy’s Advanced Research Project Agency - Energy (ARPA-E) has invested in WBG semiconductors over the past ten years targeting the barriers to widespread adoption of WBGs in power electronics including material and device development. Under ARPA-E projects, medium voltage (10-20kV) WBG device development has commenced to push the voltage boundaries of WBGs. This includes super-junction devices and light triggered photoconductive devices for MV applications. The WBG MV devices will enable MVDC grid distribution applicable to markets including electrified transportation, renewable interconnections, and offshore oil, gas, and wind production. Advanced WBG device ideas are additionally being explored including 3D device structures, WBG integrated circuits, and neutron detectors The progress and challenges of the WBG devices being developed under ARPA-E programs will be reviewed along with thoughts on the future trends of WBG device development.

Benchmarking the robustness of Si and SiC MOSFETs: Unclamped inductive switching and short-circuit performance

The reliability and robustness of power devices are key areas of research for increasing the adoption of wide bandgap power semiconductors. This paper benchmarks the robustness under short-circuit (SC) and unclamped inductive switching (UIS) of 650 V SiC trench MOSFETs, SiC planar MOSFETs and silicon super-junction MOSFETs. The performance is characterised at 75 °C and 150 °C and the results show that the SiC MOSFETs have reduced temperature sensitivity under both SC and UIS conditions, which will be beneficial from the application point of view. In the case of the silicon MOSFET, increasing the temperature enhances the short-circuit withstand time as the peak short-circuit current is reduced. The opposite trend is observed for UIS, with a reduction of robustness as the temperature is increased. The absolute SC and avalanche energies are lower for the SiC MOSFETs, but if the chip areas are considered, the energy densities are higher in the SiC MOSFETs, with the SiC Trench having a superior critical SC energy and the SiC planar having a higher avalanche energy density. The higher critical SC and UIS energy densities in SiC MOSFETs, together with their higher thermal resistances result in higher peak junction temperatures and clear hotspots are identified using Finite Element simulations.

Multilevel inverter with active clamping diodes for energy efficiency improvement

Multilevel inverters can replace commonly used two-level inverters for three-phase electrical drives. In this lowvoltage range new wide-bandgap power switches (SiC MOSFET, GaN FET) are available. In the four-, five- and sevenlevel inverters, the majority of the power losses are caused by the threshold voltage of the clamping diodes. The new idea is the replacement of the clamping diodes by active switches, since they only have low on-resistance in the forward direction. In this case freewheeling paths of the clamping diodes would have to be actively switched. However, the control signals for the clamping switches can be generated by logic operations from the control signals for the main switches. The use of active clamping switches has significant potential to reduce semiconductor losses, but requires the development of wide-bandgap power semiconductors with reverse blocking capability. At nominal motor operation point of the 5.5 kW induction motor a loss reduction of 56 % between active clamping switches and clamping diodes is possible. With a higher number of inverter levels, the size of the motor filter can be reduced by about 70 % and also the losses can be reduced by 73 %.