SiC MOSFET Inverter Research Articles

Influence of High-Frequency Operation on the Efficiency of a PMSM Drive with SiC-MOSFET Inverter

This paper investigates the effects of high-frequency switching and a high fundamental frequency on the parameters and efficiency of a high-speed permanent magnet synchronous machine (PMSM) drive. We discuss the design and modeling of the PMSM, taking into account these high-frequency effects. The impact of high frequencies is analyzed across three different inverters (IGBT, Fast IGBT, and SiC-MOSFET) and the motor, and we employ theoretical analysis, computer simulations, and experimental tests for validation. Our goal is to enhance our understanding of how these high-frequency factors affect the performance of the motor drive.

Radiation study on the parallel topology of SiC MOSFET and Si IGBT inverter

The electromagnetic radiation interference mechanism from multiple noise sources on the parallel topology of SiC MOSFET and Si IGBT Inverter is blurred, which will seriously affect the high reliability application of the structure. In order to solve this problem, a topological radiation EMI prediction method is proposed, the method includes the establishment of radiation equivalent models and radiation guidelines, the proposed inverter parallel topology radiation. The modeling method of electromagnetic interference can effectively analyze the influence of radiation interference of SiC and Si devices coupled with each other, and the established PCB radiation near and far field simulation can effectively realize the accurate prediction of radiation interference of inverter parallel topology, and finally the experimental platform of the parallel SiC MOSFET and Si IGBT inverter is built and tested, the test results demonstrate the accuracy of the proposed method.

Full Electromagnetic Integration of Impedance-Balanced EMI Filters for Single-Phase Power Converters

Utilizing passive electromagnetic interference (EMI) filters is the most widely used approach to restrain the conducted emissions from power converters. However, the introduction of these filters will significantly raise the weight and size of the systems. Using the emerging flexible multi-layer foil (FMLF) technique, this paper investigates a complete electromagnetically integrated design concept of single-phase EMI filters based on EE-type cores, which can be applicable to engineering application scenarios with different EMI noise attenuation requirements. Two types of integrated structures are constructed with different well-designed FMLF-windings and terminal configurations. One is a common-mode (CM) choke with controllable leakage inductances, which is able to realize the integration design of CM inductor, CM capacitors and differential-mode (DM) inductors. The other is an EMI choke with integrating the CM and DM inductances & capacitances, which achieves electromagnetic integration of all the CM and DM filtering components. Compared to the existing UU-type core based integration methods, the proposed methods can ameliorate the noise suppression performance while reducing filter's weight and volume. Theoretical analyses for modeling and design of the EMI chokes is presented. Then prototypes of different FMLFs based EMI filters have been built for a 500W 100kHz SiC-MOSFET inverter, experiments demonstrate the feasibility and validity of the proposed structures.

Generation of a Nanosecond Pulsed Gliding Arc Discharge With a Repetition Frequency of 300 kHz in an Air Flow at Atmospheric Pressure

Characteristics of a repetitive nanosecond pulsed gliding arc discharge in an air flow at atmospheric pressure driven by a SiC MOSFET inverter power supply are reported for the first time. The gliding arc discharge is produced using two diverging electrodes. The repetition frequency of the pulsed voltage is set from 10 to 300 kHz, and the pulse duration is 500 ns. The propagation distance of the gliding arc discharge almost linearly increases with increasing the repetition frequency of the applied pulsed voltage, resulting in an increase in the discharge reaction area. Dynamics of ignitions and propagation of the gliding arc discharge are revealed with a high-speed camera imaging synchronized with the applied pulsed voltage. The result shows that a shortcut discharge with a different generation mechanism appears. It is found that formation of a shortcut current path between the two legs of the stretched arc discharge occurs, resulting in a new ignited arc discharge. Thus, the pulsed gliding arc discharge can be repeatedly generated without a reignition at the shortest gap between the electrodes. The probability of the occurrence of the shortcut discharge increases as the repetition frequency of the pulsed voltage increases. Additionally, measurements of optical emission spectra of the gliding arc discharge show the presence of excited N2, OH, and NH radicals. The OH emission dominates in the gliding arc discharge with the shortcut events. It can be concluded that the repetition frequency of the applied pulsed voltage becomes the control knob for chemical reactions in future industrial applications.

Design of Main Circuit for an SiC-MOSFET Inverter Using a Thick Copper Multilayer PCB to Minimize Stray Inductance

Design of Main Circuit for an SiC-MOSFET Inverter Using a Thick Copper Multilayer PCB to Minimize Stray Inductance

Modeling and Implementation of Optimal Asymmetric Variable Dead-Time Setting for SiC MOSFET-Based Three-Phase Two-Level Inverters

Efficiency, power quality, and reliability of SiC MOSFET-based voltage-source converters are significantly affected by the dead-time settings. The conventional fixed dead-time setting can induce large output voltage loss and additional energy loss due to the output capacitance of the SiC MOSFETs and the SiC Schottky barrier diodes or the freewheeling of the diodes, which will be more serious under high switching frequencies. This paper analyzes and models the detailed switching process of the SiC MOSFET half-bridge circuit when various dead-time settings are adopted. Based on the models, an optimal asymmetric variable dead-time (OAVDT) setting is proposed, which can avoid the discharging loss of the output capacitance and redundant freewheeling loss of the diode. The OAVDT setting is realized by adjusting the optimal dead-time in real time after the active device is turned off , which does not require any additional hardware circuits. The OAVDT setting can also reduce the output voltage loss to a certain level compared to the fixed dead-time setting. A three-phase two-level SiC MOSFET inverter has been built in the lab to verify the proposed OAVDT setting. Experimental results show a decrease of power loss by 22.5% with reduced output voltage loss compared to the fixed dead-time setting of 0.28 μs when the output power is 8 kW and the switching frequency is 40 kHz. The proposed OAVDT setting shows clear advantages over that of fixed dead-time setting, especially at light load and high switching frequencies.

Thermal analysis for optimized selection of cooling techniques for SiC devices in high frequency switching applications

The inception of wide bandgap power semiconductors has paved way for the evolution of highly efficient power switches. A deep understanding about the thermal characteristics of the SiC power device is essential to utilize its advantages in terms of higher thermal and power handling capability. The primary objective of this paper is to establish an accurate thermal model by proposing and comparing different methodologies for thermal analysis of commercially available SiC device, which in turn will aid to select optimum cooling techniques for higher system efficiency. Exponential curve fitting technique was exploited to deduce the parameters for RC equivalent network model. A high frequency sinusoidal pulse width modulated SiC MOSFET inverter with a fixed load was considered for electro-thermal analysis using a unified software platform PLECS. The effect of switching frequency on heat sink volume was established through simulation studies with imbibed datasheet parameters of a commercial power device. Finally, a 3-D model of the commercially available SiC power MOSFET in SOT-227B package was built to analyse the device heat dissipation profile for an optimized cooling choice. The proposed modelling approach serves to provide a platform for the thermal optimization of power devices and can be extended to other semiconductor devices.

Improving the Overall Efficiency of Automotive Inverters Using a Multilevel Converter Composed of Low Voltage Si mosfets

In order to improve the driving range and reduce the cost of battery electric vehicles through a higher efficiency, this paper proposes to adopt multilevel converters using low-voltage Si mosfet s in the electric powertrains. A multilevel Si mosfet inverter, a conventional insulated-gate bipolar transistor (IGBT) inverter, and a SiC mosfet inverter are modeled and compared using a reference vehicle over various driving cycles. The costs of the three solutions are also compared. It is shown that the multilevel Si mosfet inverter has a rather high efficiency and realizes the lowest cost among the three solutions even when the worst case of cost is considered. Sensitivity analysis also shows that the multilevel Si mosfet inverter is suitable for a wide range of vehicle concepts in addition to the reference vehicle. Moreover, the multilevel topology also features lower electromagnetic interference and provides modularity. Therefore, Si mosfet -based multilevel inverters are proved in this paper to be an appropriate option to improve the efficiency and reduce the cost of electric powertrains.

Inverter Side RL Filter Precise Design for Motor Overvoltage Mitigation in SiC-Based Drives

This paper investigates the use of resistor–inductor (RL) filters for motor overvoltage issues caused by cables connecting inverters to electric machines. Using existing filter design formulae and fixing the desired peak motor voltage, an RL filter is designed for a 15-kW industrial drive. This filter is used with a Silicon IGBT inverter and a matching between the design targets and the experimental results are found. Using the same filter with an SiC MOSFET inverter, a detrimental effect in overvoltage mitigation task is found. From simulations, it is noticed that combination of filter resistor parasitic inductance and high $dv/dt$ causes unpredicted additional high-frequency motor overvoltages. These phenomena require higher filter inductance values with respect to the standard one, thus previous filter design formulae cannot be used. New design formulae, valid when inverters with high $dv/dt$ are used, are proposed and experimentally validated. Interestingly, using the proposed formulae, it is discovered that the best filter resistance is not equal to the characteristic impedance of the cable. A design guideline that permits to optimally design the RL filter without simulation tool, considering the resistor parasitic inductance and the inverter $dv/dt$ is finally proposed.

Practical papers, articles and application notes

With the rapid development of high-speed wide band-gap (WBG) semiconductor devices, electromagnetic interference (EMI) in power converters has become a major design issue that cannot be ignored. The first paper "EMI Filter Design of Single-Phase SiC MOSFET Inverter with Extracted Noise Source Impedance" authored by Yitao Liu, Shiqi Jiang, Huaizhi Wang, Guibin Wang, Jian Yin and Jianchun Peng from Shenzhen University, China, describes a systematic procedure to design effective common-mode (CM) and differential-mode (DM) EMI filters for a power grid connected SiC MOSFET inverter system.

EMI filter design of single-phase SiC MOSFET inverter with extracted noise source impedance

This paper presents an electromagnetic interference (EMI) filter design procedure for a single-phase SiC MOSFET inverter. To ensure the EMI filter performance is both accurate and effective, the equivalent noise source impedances of common mode (CM) and differential mode (DM) noise models are extracted. Then the CM and DM EMI filters can be designed based on the known CM and DM noise source impedances, respectively. The EMI filter design based on the proposed method is validated both through simulation and experiments. The simulation and experiment results have verified the effectiveness of the proposed method.

Diamond-like carbon film preparation using a high-repetition nanosecond pulsed glow discharge plasma at gas pressure of 1 kPa generated by a SiC-MOSFET inverter power supply

A high-repetition nanosecond pulsed glow discharge plasma at a gas pressure of 1 kPa was generated using a SiC-MOSFET inverter power supply for diamond-like carbon (DLC) film preparation. At a high repetition frequency above 50 kHz, the period of the nanosecond voltage pulse became shorter than the decay time of the afterglow plasma, and many ions and radicals remained in the gap space. The deposition rate was 0.1 µm/min, which was 5 times higher than that of a conventional plasma CVD process. An increase in hardness to 13 GPa and a decrease in hydrogen content in the DLC film were confirmed by increasing the repetition frequency to 200 kHz.

Comparitive Loss Evaluation of Si IGBT Versus Sic Mosfet (Silicon Carbide) for 3 Phase Spwm Inverter

Background/Objectives: Reducing the losses of 3 phase spwm 2 level inverter by replacing the present semi conductor switches which are si igbt (silicon) with the latest sic mosfet (silicon carbide) switches. Methods/Statistical Analysis: si igbt (silicon) and sic mosfet (silicon carbide) are modelled in pspice using the data sheet parameters and the modelled switches are used to simulate the three phase spwm inverter and the losses of the system are compared. Findings: The three phase spwm inverter simulated at switching frequency ranges of 5khz, 8khz, 10khz, 15khz and it had been observed that the losses of the 3 phase spwm sic mosfet inverter are 29% less for 5khz switching frequency, 34% less for switching frequency of 8khz, 37% less for switching frequency of 10khz, 42% less for the switching frequency of 15khz over the 3 phase spwm inverter based on si igbt. Application/Improvements: The sic mosfet can replace the si igbt in 3 phase spwm inverter system for better efficiency and the pspice simulations showed similar results showing that sic mosfet is efficient than si igbt based three phase spwm inverter.

Design and Performance of Compact Air-Cooled SiC MOSFET Inverters for Low-Power Variable Speed Drive Applications

Design and experimental results of a scalable and modular air-cooled power inverter using commercial SiC power MOSFETs are reported. Compared to the well-established silicon IGBT power inverter, the new SiC power MOSFET inverter offers 40% more output power and 4% higher efficiency for a 10kW, 20kHz air-cooled design. A detailed design and performance tradeoff is presented from a system-level perspective in terms of cost/kW for SiC inverter for vehicle electrification and power generation applications. The design is based on a simple circuit simulation model developed from measurements made on commercially available packaged discrete SiC power MOSFETs.