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A gallium nitride (GaN)-based resonant step-up converter is proposed for the application in the satellite electric propulsion (EP) system. This converter consists of a full-bridge inverter, a resonant tank and a multi-stage Cockcroft-Walton (CW) voltage multiplier to provide a high gain. Additionally, the air-core transformer is introduced due to the megahertz switching frequency allowed by the GaN device. Thus, the limited magnetizing inductance of transformer and the remarkable junction capacitance of diode have to be carefully considered in the resonant tank design, especially after considering that this converter normally operates at the light load in the EP system. In this work, the 4-order LCLC resonant converter is investigated. The recommended parameter selection for the 4-order resonant tank is also provided. A 1.2-MHz, 23-V/2.5-kV, and 6-W prototype is demonstrated. It achieves a low harmonics distortion and a low power loss with the zero voltage switching (ZVS).

Ultra-fast switching speed and low switching loss of the gallium nitride high electron mobility transistors enable the realisation of high power density converter with excellent conversion efficiency. However, the rapid switching transition leads to significant overshoot and crosstalk issues that can degrade the performance of the devices. To facilitate the evaluation of these effects on low-voltage gallium nitride devices, this paper develops an analytical model to predict overshoot and crosstalk during switching transitions accurately and efficiently. The model is constructed based on the detailed circuit deduction of various stages of the device's switching process. It also considers the voltage-dependent junction capacitances as well as the forward and the reverse transconductances. The simulated results obtained from the model are validated experimentally. With the model, the impacts of parasitic elements, especially the power loop inductance, on voltage/current overshoots and spurious voltage due to crosstalk can be easily evaluated, which provides valuable design guidelines for power conversion applications using low-voltage gallium nitride high electron mobility transistor. Published version This work was supported in part by the Project for Transformation of Scientific and Technological Achievements in Sichuan Province under Grant M112021ZHCG0011, and in part by the Aircraft Swarm Intelligent Sensing and Cooperative Control Key Laboratory of Sichuan Province.

Gallium nitride (GaN) high electron mobility transistor (HEMT) is a promising candidate for the high-density power converter applications. Due to the low switching loss, the GaN HEMT may lead to a new horizon in the applications, such as fast charger, wireless charging, and 5G power amplifier. However, the fast switching speed of GaN HEMT makes it extremely sensitive to parasitic parameters, especially for the low-voltage GaN devices with small packages. Conventional switching loss estimation methods, which are normally based on the calibration fixture or modification of test circuit, cannot be effectively utilized for GaN HEMT. This article presents an accurate switching loss estimation method using the postprocessing technique. The proposed switching loss technique consists of three parts of signal processing, which are the wavelet denoising process to minimize the influence of background noise, the voltage–current ( $ V-I$ ) alignment process to reduce errors from probe propagation delay, and the linear interpolation process for further improvement of alignment accuracy. In addition, a modified SPICE model is proposed to investigate the influence of parasitic parameters on switching losses by the circuit simulation. Based on the theoretical switching characteristics, the switching loss estimation method is finally validated experimentally on a commercial 40-V/10-A GaN HEMT in a double-pulse test.

In-circuit impedance measurement provides useful information for many EMC applications. The inductive coupling approach is a promising in-circuit impedance measurement method due to its non-contact characteristics and simple on-site implementation. Many measurement setups of this approach were reported. However, a comprehensive survey and comparison of these setups have not been found in the literature. This paper reviews these setups in terms of their characteristics, limitations, and applications. In addition, recommendations for future research are also presented., The paper has been accepted to be presented at the 2022 Asia-Pacific International Symposium on Electromagnetic Compatibility (APEMC) in July 2022

The step-up resonant converter serves as an essential part of the ion propulsion power suppy (IPPS), which has been widely used in micro- and nano-satellites. However, the common-mode (CM) noise could deteriorate the converter performance, and hence it needs to be evaluated and mitigated. This work studies the CM noise of a 2 W, 500 kHz, 15-V/1.2-kV Gallium Nitride (GaN) based LCLC resonant converter. Based on the working principle of this converter, the CM noise current path is analyzed. In addition, an LCL filter is applied to evaluate its performance for CM noise suppression. The experimental and simulation results show that significant CM noise exists in the GaN-based step-up LCLC resonant converter from the frequency range of 150 kHz to 30 MHz, and the LCL filter realizes a good suppression for the CM noise.

Due to the advantages of high efficiency, low mass, modularization and high power density, the step-up resonant converter is widely adopted in providing kV-level high voltage for the ion propulsion power supply. As a key part of the resonant converter, the resonant tank topology is evaluated in this paper. Based on the characteristics of the high-voltage resonant converter, a selecting criteria for the resonant tank is proposed. Applying the criteria to the 2-element, 3-element, and 4-element resonant tank topologies, the candidate for high-voltage application can be recommended. Then, the selected topologies are compared based on the relationship between voltage gain and frequency. The analytical results show that the gain valley could be more easily founded in the 4-element resonant tank compared with others, thus it is more suitable for the high-voltage application.

GaN HEMT is a promising alternative of Si MOS-FET for the high-density power converter applications. Due to their lower switching losses, GaN HEMT may lead to new horizons in the application area of power electronics such as faster charger, wireless charging, and 5G power amplifier. However, evaluation of power loss and EMI of GaN HEMT versus Si MOSFET for the application in a synchronous low-voltage buck converter have not been comprehensively investigated. In this paper, the application boundary of 40-V, 10-A GaN HEMT is analyzed by comparing with Si counterpart has been assessed in terms of power loss, oscillation and EMI though the double pulse test. Based on the DPT results, it can be found that the switching energy of GaN HEMT is nearly 1/10 of Si MOSFET and also exhibits zero reverse recovery loss. Additionally, the impact of different switches on the converter performances is analyzed by the PLECS thermal simulation. It can be found that GaN-based converter shows lower efficiency at low frequency, and its efficiency is more seriously influenced by the dead time which is its application boundary.

This paper proposes a nonlinear speed controller in order to avoid the tracking speed problem of the finite-set model predictive current control (FS-MPCC) for linear induction machine (LIM). The speed of the LIM is regulated using the terminal sliding mode controller (TSMC) instead of the conventional PI controller aiming to achieve faster dynamic response with less steady-state error. The output of the TSMC serves as the q-axis primary current reference of the FS-MPCC. The mathematic model of the proposed TSMC based on FS-MPCC is implemented in the αβ frame instead of the dq frame to decrease the computation time and avoid the complex frame transformation. Finally, the control performance of the proposed strategy is verified by simulation and experiments which are based on the platform of two 3 kW arc induction machines (demonstration on the LIM performance in practice).

Gallium nitride (GaN) high electron mobility transistor (HEMT) is a promising candidate for the high-efficiency and high-frequency motor drive applications when compared with the silicon (Si) counterpart. In this work, the GaN-based and Si-based devices based full bridge converters for DC motor drive are investigated and compared. Firstly, three different driving schemes including bipolar, unipolar and synchronous rectification are analyzed. Then, performance comparison between 40-V/l0-A GaN HEMT and Si MOSFET are conducted based on the datasheet and double pulse test experiment results. Finally, the model of DC motor drive is proposed based on PLECS thermal simulation. Based on the model, the impact of three schemes and two different switches on the efficiency is investigated. Results show the GaN-based full-bridge converter has higher efficiency and lower power loss.

The aim of this paper is to design a sensorless voltage control strategy with the aid of model reference adaptive system (MRAS) for rotor-position detection procedure of the promising brushless doubly-fed induction generators (BDFIGs) in the ship shaft stand-alone applications. The detected new methodology of MRAS is based on the power winding (PW) field-oriented control technique and the functional quantity of control winding (CW) active power. The proposed sensorless control system has ensured the efficacy and simplicity due to the absence of the flux computation process. Comprehensive simulation and experiments based on a wound-rotor BDFIG prototype has demonstrated that the presented MRAS method has strong dynamics during various operations for the promising BDFIGs in the stand-alone systems.

The leucine‑rich repeats and immunoglobulin‑like domains (LRIG) gene family, comprising LRIG1, 2 and 3, encodes integral membrane proteins. It has been well established that LRIG1 negatively regulates multiple growth factor signaling pathways and is considered to be a tumor suppressor; however, the biological functions of LRIG2 remain largely unexplored. It was previously demonstrated that LRIG2 positively regulates epidermal growth factor receptor (EGFR) signaling, the most common aberrant receptor tyrosine kinase (RTK) signaling in glioblastoma multiforme (GBM), which promotes GBM growth. In the present study, the effect of LRIG2 on the proliferation of GBM cells was further addressed, as well as the possible mechanisms underlying the regulatory effect of LRIG2 on platelet‑derived growth factor receptor β (PDGFRβ) signaling, another common oncogenic RTK signaling pathway in GBM. First, the expression levels of endogenous LRIG2 and PDGFRβ were found to vary notably in human GBM, and the LRIG2 expression level was positively correlated with the expression level of PDGFRβ. Furthermore, to the best of our knowledge, this is the first study to demonstrate that LRIG2 promoted the PDGF‑BB‑induced proliferation of GBM cells in vitro and in vivo through regulating the PDGFRβ signaling‑mediated cell cycle progression. Mechanistically, LRIG2 has the ability to physically interact with PDGFRβ, promoting the total expression and the activation of PDGFRβ, and enhancing its downstream signaling pathways of Akt and signal transducer and activator of transcription 3 and the effectors of key regulators of cell cycle progression, resulting in increased GBM cell proliferation. Collectively, these data indicated that LRIG2 may serve as a tumor promoter gene in gliomagenesis by positively regulating PDGFRβ signaling, another important oncogenic RTK signaling pathway, in addition to the previously reported EGFR signaling in GBM modulated by LRIG2, and validated LRIG2 as a promising therapeutic target for the treatment of GBM characterized by multiple aberrant RTK signaling.

In this paper, one improved speed control algorithm of linear induction motors (LIMs) using sliding mode control (SMC) is firstly proposed. Then, an extended sliding mode load thrust observer (ESO) has been proposed to compensate the sliding mode controller under the load thrust disturbance. Moreover, the SMC integrated with ESO is designed based on direct thrust control (DTC) technique with space-vector modulation (SVM) to regulate speed, flux, and thrust of the LIM. The output of the SMC is considered as the reference thrust for the DTC based on space-vector modulation (DTC-SVM). A comparison between the proposed method and the conventional method with PI controllers is presented to illustrate the superiority of the proposed control method. Comprehensive simulation results have demonstrated that the proposed control scheme has a better transient control performance with a fast and good speed tracking.

An improved control scheme for surface mounted permanent magnet synchronous motor (PMSM) is proposed for the high-speed range operation with a torque ripple reduction. The onset of flux weakening is adjusted naturally by the outer duty cycle regulation loop to prevent the saturation of the current regulators. Meanwhile, the predictive q-axis current ripple is utilized to vary switching frequency pulse width modulation (VSFPWM) of the inverter. Hence, the maximum value of the torque ripple can be controlled. Simulation results have demonstrated the effectiveness of the proposed control strategy.

Direct thrust control based on space-vector modulation (DTC-SVM) can achieve constant switching frequency and reduce thrust and flux ripples compared to conventional DTC. This paper presents DTC-SVM to improve the performance of linear induction motor (LIM). More enhancements can be achieved by using a sensorless method of the linear speed for LIM. The estimation method is based on model reference adaptive system (MRAS). Proportional Integral (PI) controller is used to control the speed of LIM. The output of the PI controller is considered as the reference thrust for DTC-SVM. The overall system performance and effectiveness of the proposed method are evaluated via comprehensive simulations results where lower ripples associated with both thrust and flux linkages waveforms and better speed tracking.

This paper proposes a speed control of linear induction motor (LIM) based on a finite-set model predictive flux control (FS-MPFC). The end effect is taken into consideration for both modeling of LIM and for the proposed control method. The proposed control method is used to achieve lower thrust ripple, reduce the calculation process and eliminating the weighting factor from the cost function. The cost function is based only on the primary flux linkage error in αβ-coordinates. The primary flux linkage error is calculated from the difference between the reference primary flux linkage and the predicted primary flux linkage. A comparison between the proposed method and the finite set model predictive direct thrust control (FS-MPDTC) is presented to illustrate the simplicity of the proposed method. The performance of the proposed control strategy is verified by simulation results where the parameters of a 3kW platform arc induction machine is used.

In this paper, one improved speed control algorithm of the linear induction motor (LIM) using finite-set model predictive direct thrust control (FS-MPDTC) is firstly proposed. Then speed estimation method for LIM is proposed using model reference adaptive system (MRAS) method. FS-MPDTC is used to reduce the thrust ripples instead of conventional direct thrust control. PI controller is used to regulating the speed where the output of the PI controller serves as the reference thrust of FS-MPDTC. The proposed control scheme aims at improving the performance of the LIM drive system, where low cost, low thrust and flux ripple and fast response can be achieved. A platform is developed in the laboratory with two 3 kW arc induction motors. Comprehensive simulations and experimental results have demonstrated that the proposed control scheme has a better performance in reducing the ripples associated with both thrust and flux linkages waveforms. Moreover, the obtained results confirm the effectiveness of the estimation method in tracking the measured speed.

With the superior features of lower cost and higher power density, the permanent magnet synchronous motor (PMSM) based adjustable speed drive (ASD) system has been paid much more attentions recently. A high-frequency (HF) model of PMSM is proposed to predict the conducted electromagnetic interference (EMI) emission, which brings much detrimental affection to the ASD system, in this paper. This model can depict the impedance characteristics of a three-phase surface-mounted PMSM from $0.1 \mathrm {k}\mathrm {H}\mathrm {z}$ to 10 MHz well. Then, experiment is implemented to validate the proposed HF model for EMI prediction. The experimental results manifest that the model is able to calculate CM voltage, CM current, and phase current of the PMSM in a simplified ASD system correctly. Therefore, the proposed HF model of PMSM is expected to provide much more instructions for EMI predicting in the ASD system.

The motor drive has been widely adopted in modern power applications. With the emergency of the next generation wide bandgap semiconductor device, such as silicon carbide (SiC) MOSFET, performance of the motor drive can be improved in terms of efficiency, power density, and reliability. However, the fast switching transient and serious switching ringing of the SiC MOSFET can cause unwanted high-frequency (HF) electromagnetic interference (EMI), which may significantly reduce the reliability of the motor drive in many aspects. In order to comprehensively reveal the mechanism of the EMI previously used in motor drives using SiC MOSFET, this paper plans to analyze the influences of both HF impedance of the motor and switching characteristics of the SiC MOSFET. A simulation model for motor drives has been proposed, which contains the HF circuit model of the motor as well as a semi-behavioral analytical model of the SiC MOSFET. Since the model shows a good agreement with the experimentally measured results on spectra of drain-source voltage of the SiC MOSFET (vds), phase to ground voltage of the motor (vphase), CM voltage (vcm), phase current of the motor (idm), and CM current (icm), it can be adopted to quantitatively investigate the influence of the motor impedance on EMI through frequency-domain analysis. Additionally, the impacts of switching characteristics of SiC MOSFET on EMI are also well studied according to relative experiment results in terms of switching speed, switching frequency, and switching ringing. Based on the analysis above, the relationship between motor impedance, switching characteristics of the SiC MOSFET, and HF EMI can be figured out, which is able to provide much helpful assistance for application of the motor drive.

Under the influence of high speed power switch device, electromagnetic interference (EMI) affects heavily the normal operation of the buck-boost circuit in hybrid energy storage system (HESS). In this paper, the working principle of the buck-boost converter in hybrid energy storage system is analyzed, and the relationship between common-mode (CM) voltage and the voltage of switching device is obtained. By analyzing the frequency spectrum of the voltage of switching device, the relationship between the switching characteristics and the system conducted electromagnetic interference is proposed, and the prediction model of the conducted electromagnetic interference for hybrid energy storage system is established. In addition, the mechanism of ringing and overshoot during switching time of switching devices is studied and reduced by the method of adding capacitor, and experimental results validate the analysis method.

In this paper, top joint method is proposed to solve a practical engineering problem of temperature stress and temperature crack of super-long slab-column structure bearing temperature difference. From the study, it is shown that as for super-long slab-column structure undergoing temperature difference of inside and outside, joint located in bottom stories nearly has no influence on temperature stress and deformation while joint in top stories can significantly reduce temperature stress and deformation of super-long slab-column structures. In addition, comparison of joints located in top one story, top several stories and from bottom to top stories indicates that influences of them on temperature stress and deformation are similar. As for top joint method, among which cantilever plate method, double column method and corbel method are discussed and results indicate that influence effects of these methods on structures are similar.