Showing papers in "IEEE Transactions on Industrial Electronics in 2023"
TL;DR: In this paper , a time-series reconstruction method based on spectral features was proposed to detect arc faults in multiload ac series arc fault (SAF) detection, and the results show that the presented approach has good generalization performance and identification precision under arbitrary circuits.
Abstract: This article investigates into signal regularity in ac series arc fault (SAF) detection. The regularity can solve the vital problem that SAF current characteristics change or disappear in unknown multiload circuits. A coupling method is adopted to capture high-frequency differential signals. The coupling signals show that the waveform in single-load circuits closely resembles the waveform in multiload ones. However, the coupling method confuses normal signals with arcing ones in dimmer loads. To address the issue, this article presents a time-series reconstruction method based on spectral features. First, the spectral features are analyzed between fault-like signals and fault signals. According to the spectral features and the desirable margin, the time series is self-adaptively decomposed and reconstructed. Then, the pulse-recognition algorithm is used to extract arcing features of the reconstructed signals. Finally, the detection method determined by single-load circuits is used to identify SAFs in unknown multiload ones. The results show the presented approach has good generalization performance and identification precision under arbitrary circuits.
5 citations
TL;DR: In this article , a multicharacteristics arc model is established based on the volt-ampere, current sag, and power spectral characteristics of arc faults, and a noninvasive arc fault detector based on magnetic-field sensing and autocorrelation algorithm is developed.
Abstract: DC microgrids contribute to the increasing penetration of renewable energies. However, a dc arc fault will lead to malfunctions and even fire hazards in a dc microgrid. To ensure the safe and efficient operation of a dc microgrid, the characteristics of dc arc faults should be determined, and a reliable arc-fault detection technique is required. Nevertheless, it is difficult to investigate the dc arc faults in a practical system. Thus, an accurate and reliable arc model for simulation research of arc faults is significant. Since a dc microgrid has numerous branches, the existing arc models cannot express the complex and random characteristics of potential arc faults. Besides, the detection points need to be determined for the appropriate installation of arc fault detectors. Furthermore, the arc features may be ambiguous and affected by the environmental noise and power electronics noise leading to nuisance tripping to arc detectors. In this article, a multicharacteristics arc model is established based on the volt-ampere, current sag, and power spectral characteristics of arc faults. According to the frequency domain features of arc faults and interaction effects between different branches, the arc-detection-point selection principle is formed. A noninvasive arc fault detector based on magnetic-field sensing and autocorrelation algorithm is developed. It can avoid the effects of periodic environmental noise and power electronics noise by comparing the correlation between arc features in periods. The experimental results verify that the arc faults can be detected with high accuracy by installing the autocorrelation-algorithm-based arc detector at detection points selected by the arc-detection-point selection principle in a dc microgrid.
5 citations
TL;DR: Experimental results show that the proposed novel data association method for cuboid landmarks based on Dirichlet process mixture model not only associates cuboids robustly but also achieves SOTA pose estimation accuracy in monocular SLAMs.
Abstract: Semantic simultaneous localization and mapping (SLAM) with a monocular camera is particularly attractive because of the deployment simplicity and economic availability. Data association problem which assigns unique identities for objects shown in multiple frames plays a fundamental role in semantic SLAM. Previous prevalent methods which mainly focused on associating geometric KeyPoints are no longer suitable. Some naive methods that rely on object distance or 2-D/3-D Intersection over Union are also vulnerable when occlusions happen. In this article, we propose a novel data association method for cuboid landmarks based on Dirichlet process mixture model. By jointly considering object class, position, and size, our method can perform data association robustly. We evaluated our method in simulated datasets, public benchmark KITTI, and on a real robot in an office environment. Experimental results show that our method not only associates cuboids robustly but also achieves SOTA pose estimation accuracy in monocular SLAMs.
4 citations
TL;DR: In this paper , the authors proposed an interleaved boost-integrated LC series resonant converter, in which the IC is located on the secondary side and the input and output of the IC are in series directly, which can reduce the voltage stress of the output filter capacitor of boost unit.
Abstract: In this article, we propose a novel interleaved boost-integrated LC series resonant converter, in which the series resonant tank is located on the secondary side. Moreover, the input and output of the interleaved boost unit are in series directly, which is helpful to reduce the voltage stress of the output filter capacitor of boost unit. With the proposed pulse frequency modulation, except for that the output voltage can be controlled as constant under different input voltages, another feature is that the high-frequency transformer design is related to the series resonant frequency instead of the switching frequency. Hence, the proposed converter can operate under a very wide switching frequency range with a constant maximum magnetic flux density. The zero voltage switching and zero current switching can be achieved for all switches diodes. Finally, a 500-W prototype with a switching frequency range from 60 to 200 kHz is built to verify the operation principles of the proposed converter and modulation.
4 citations
TL;DR: In this paper , an event-triggered consensus control for a group of mobile robots based on cooperative localization (CL) is investigated. But the authors focus on the problem of minimizing the frequency of control updates and unnecessary transmission of information between system components.
Abstract: In multirobot systems, the accurate localization of each mobile robot in the team is a prerequisite to reach consensus. This article investigates the problem of event-triggered consensus control for a group of mobile robots based on cooperative localization (CL). In our framework, each robot employs the position estimates from CL to jointly achieve consensus. An event-triggered mechanism based on a mixed-type condition is adopted in order to reduce the frequency of control updates and unnecessary transmission of information between system components. Our goal is to design an event-triggered consensus controller based on CL such that the closed-loop system achieves the prescribed consensus in spite of inaccurate sensor measurements. We provide sufficient conditions that guarantee the desired consensus using eigenvalues and eigenvectors of the Laplacian matrix. We design the controller and filter gains as well as the parameters of the event-triggering mechanism simultaneously in terms of the solution for a linear matrix inequality. Finally, simulation and experimental results are used to demonstrate the effectiveness of proposed approach.
4 citations
TL;DR: In this paper , the authors proposed a new time-domain pilot protection based on two-dimensional (2D) space projection of dual differential currents for lines connecting converter stations, which exhibits exceptional performance in operating speed, sensitivity, complexity, tolerance to fault resistance, current transformer saturation and abnormal data.
Abstract: As an important topic of power system protection, protection algorithm for transmission lines connecting modular multilevel converter (MMC)-based converter stations has attracted extensive attention. This article proposes a new time-domain pilot protection based on two-dimensional (2-D) space projection of dual differential currents for lines connecting converter stations. The dual differential currents, i.e., original and virtual differential currents, are projected into 2-D space. Subsequently, the dynamic trajectories of dual differential currents under various circumstances are elaborated. On this basis, the nonoperating zone and internal fault index are defined, whereby the criterion of pilot protection is developed. Afterwards, the operating characteristic of the proposed pilot protection is analyzed under various circumstances. The performance of proposed pilot protection is widely assessed using power systems computer aided design (PSCAD) and real time digital simulator (RTDS). The contribution of this article lies in a new time-domain pilot protection based current trajectory of dual differential currents, which exhibits exceptional performance in operating speed, sensitivity, complexity, tolerance to fault resistance, current transformer saturation and abnormal data, and adaptability to operation mode of MMC.
4 citations
TL;DR: In this article , an online CRA monitoring method based on Ileak for IGBTs is proposed, which can be used in slight aging situation with high sensitivity because leakage is linear to the CRA levels.
Abstract: Online aging monitoring is the basis for high reliability operation of Insulated gate bipolar transistors (IGBTs). Most monitoring methods focus on the package-related aging. Leakage current (Ileak) has been proposed as a potential chip-related aging (CRA) indicator for IGBTs. However, this method has not been implemented online due to the difficulty in accurate online leakage current measurement. An effective online CRA monitoring method is still required for IGBTs. A novel online CRA monitoring method based on Ileak for IGBTs is proposed in this article. First, an online Ileak measurement circuit is proposed. Second, based on this circuit, an aging monitoring strategy is presented. Finally, accelerating aging tests validate the effectiveness of the proposed method. The on-state voltage drop is selected as an aging indicator for comparison. The proposed method has three advantages. The online CRA monitoring is achieved. It can be used in slight aging situation with high sensitivity because Ileak is linear to the CRA levels. The measurement circuit required by this method is simple and low-cost.
4 citations
TL;DR: In this paper , an isolation forest (IF) based submodule (SM) switch open-circuit fault localization method for MMCs is proposed, which uses sparsity and difference properties of outlier data to localize fault, and accordingly it simplifies calculation complexity.
Abstract: Fault localization is one of the most important issues for modular multilevel converters (MMCs) consisting of numerous switches. This article proposes an isolation forest (IF) based submodule (SM) switch open-circuit fault localization method for MMCs. Based on the continuous sampling SM capacitor voltages, a number of isolation trees (ITs) are produced to construct the IFs for MMCs. Through the comparison of continuous IFs’ outputs, the faulty SM can be effectively localized. The proposed IF-based fault localization method only requires SM capacitor voltages in the MMC to construct concise low-data-volume tree models, and uses sparsity and difference properties of outlier data to localize fault, and accordingly it simplifies calculation complexity. In addition, it does not require the MMC's mathematical models and manual setting of empirical thresholds. Simulation and experiment are conducted, and the results confirm the effectiveness of proposed method.
4 citations
TL;DR: In this article , a hybrid five-level converter (H5LC) with cascaded full-bridge submodules (FBSMs) for high voltage direct current (HVdc) transmission is presented.
Abstract: This article presents a hybrid five-level converter (H5LC) with cascaded full-bridge submodules (FBSMs) for high voltage direct current (HVdc) transmission. A five-level converter operates at a fundamental switching frequency to generate symmetric five-level square wave output voltages which are shaped into smooth sinusoidal voltages by the ac-side FBSMs. Using a proposed third-order harmonic voltage injection scheme, the FBSMs’ total blocking voltage is limited to one-eighth of the dc-side voltage, reducing the H5LC's losses, footprint, and capital costs. dc pole-to-pole fault blocking is enabled using a bypass branch consisting of bidirectional thyristor valves and fast mechanical switches to suppress the ac-side fault contribution within half a fundamental cycle. Full-scale HVdc simulation studies show the H5LC's ability to control real and reactive powers and additionally, its dc fault resilience. A lab-scale hardware implementation of an H5LC with 30 FBSMs is presented to verify its operating principle. In contrast to the half-bridge submodule based modular multilevel converter, the H5LC has improved efficiency, fewer semiconductor devices, and significantly reduced energy storage requirements.
4 citations
TL;DR: In this paper , a 2.5m five-stage inductive power transfer (IPT) system based on domino cylindrical solenoid coupler (CSC) compensated, respectively, in layers is proposed.
Abstract: In this article, a 2.5m five-stage inductive power transfer (IPT) system based on domino cylindrical solenoid coupler (CSC) compensated, respectively, in layers is proposed. The system is considered to be used as 220 kV post insulators application, transferring power for sensors and measuring instruments of smart grids. The distributed series compensation method is applied to double-layer CSC. Compared with the two types of parallel schemes, this method can significantly reduce the current of the main circuit. Compared with the concentrated series compensation method, this method can effectively reduce the resistance caused by the stray capacitance. The interaction between the post insulator and the magnetic coupling structure is analyzed. The circuit model of the system with constant voltage output characteristics is analyzed. A prototype with a maximum efficiency of 66.7% is built. When the power is transferred to a larger value of 77.8W, the efficiency can still reach 62%. Comparing with previous works, the wireless distance is extended while the efficiency is improved.
3 citations
TL;DR: In this article , a self-attention mechanism is introduced in the policy network to improve the ability of the network to extract collaborative information between agents from the observation data, and the learned policy achieved good performance without communication between agents.
Abstract: Multiagent path finding (MAPF) is employed to find collision-free paths to guide agents traveling from an initial to a target position. The advanced decentralized approach utilizes communication between agents to improve their performance in environments with high-density obstacles. However, it dramatically reduces the robustness of multiagent systems. To overcome this difficulty, we propose a novel method for solving MAPF problems. In this method, expert data are transformed into supervised signals by proposing a hot supervised contrastive loss, which is combined with reinforcement learning to teach fully-decentralized policies. Agents reactively plan paths online in a partially observable world while exhibiting implicit coordination without communication with others. We introduce the self-attention mechanism in the policy network, which improves the ability of the policy network to extract collaborative information between agents from the observation data. By designing simulation experiments, we demonstrate that the learned policy achieved good performance without communication between agents. Furthermore, real-world application experiments demonstrate the effectiveness of our method in practical applications.
TL;DR: In this paper , an intensive comparison of interior permanent magnet motors with three design approaches to reduce cogging torque, torque ripple, and electromagnetic vibration is presented, and intensive experimental tests are done to verify the analysis and comparison.
Abstract: Interior permanentmagnet (IPM) motors have been the most promising solutions for electric vehicles (EV) drives in terms of torque/power density, compactness, and efficiency. However, IPM motors are vulnerable to large torque ripple and high-level electromagnetic vibrations due to the differences of d-&q-axis inductance and abundant spectrum of exciting forces. This article presents an intensive comparison of IPM motors with three design approaches to reduce cogging torque, torque ripple, and electromagnetic vibration. The design approaches compared cover skewing slot and segmented rotor approaches commonly used in industry, as well as a new asymmetric pole approach. A commercial 10 kW 8-pole/ 48-slots V-shaped IPM motor for EV traction is taken as the reference base. Extensive performance comparisons, including cogging torque, back-EMF, load current, load torque profiles, PM reliability, and torsional force were carried out. Besides, vibration aspects in terms of exciting force, modal property, and electromagnetic vibration response were also analyzed and compared. Finally, the prototypes with the mentioned three design approaches are produced, respectively, and intensive experimental tests were done to verify the analysis and comparison.
TL;DR: In this paper , the authors presented the dynamic modeling and analysis of an electric motor with integrated magnetic spring (EMMS) when it is coupled to a weaving loom application, and a complete experimental setup was constructed to validate the effectiveness of the proposed dynamic model and the EMMS behavior.
Abstract: This article presents the dynamic modeling and analysis of an electric motor with integrated magnetic spring (EMMS) when it is coupled to a weaving loom application. The EMMS can provide the majority part of the oscillating part of the load in a passive way by the magnetic spring. The electric motor provides the average torque and the remaining oscillating part in an active way. This reduces the energy consumption. To create an accurate dynamic model for the EMMS, lookup tables are generated from a finite-element model. Further, a 4-bar linkage mechanism is employed to emulate the behavior of the shedding mechanism of a real weaving loom application. Eventually, the whole system dynamic model was created in Matlab environment. Moreover, a complete experimental setup was constructed to validate the effectiveness of the proposed dynamic model and the EMMS behavior. It is shown that the proposed dynamic model effectively predicts the performance of the EMMS system. Besides, it is proved that the EMMS can effectively reduce the energy consumption of the weaving loom application. The amount of reduction in the energy consumption depends on the designed magnetic spring. For the considered application, it can reach 57%.
TL;DR: In this paper , a machine learning (ML) diagnosis strategy for open-circuit faults in MMC based on extreme gradient boosting (XG-Boost) was proposed, which can diagnose the fault within 20 ms with accuracy as high as 99.6% under the interference of Gaussian noise and the capacitor voltage data missing.
Abstract: The diagnosis of open-circuit faults is required for the reliability of modular multilevel converters (MMC) and the complex operating environment of MMC may cause missing data and external noise in signal detections, where some of the present open-circuit fault detection methods can be disabled. This article proposed a machine learning (ML) diagnosis strategy for open-circuit faults in MMC based on extreme gradient boosting (XG-Boost). In this method, after data processing, the data segments composed of real-time capacitance voltage and current data are input into the trained XG-Boost multiclassification model for fault diagnosis without manually setting the empirical threshold, as is required in traditional change-of-rate-of-voltage-based diagnosis methods. This method has excellent robustness against external noise and missing data while better accuracy, higher speed, and lower real-time calculation cost than existing ML-based methods are achieved. The effectiveness of the proposed method is verified by experiment results. It can diagnose the fault within 20 ms with accuracy as high as 99.6%, even under the interference of Gaussian noise and the capacitor voltage data missing.
TL;DR: In this paper , an optimal primary-side duty modulation (OPDM) is proposed to overcome the drawbacks of conventional modulations, which combines phase shift modulation and asymmetrical duty modulation on the primary side to achieve a compromise between high efficiency performance and lower control complexity.
Abstract: Dual active bridge (DAB) is a popular interface between energy sources and electric vehicle storage systems because of its galvanic separation, bidirectional power transmission, and extensive voltage adjustability. To overcome the drawbacks of conventional modulations, an optimal primary-side duty modulation (OPDM) is proposed in this article, which combines phase-shift modulation and asymmetrical duty modulation on the primary side to achieve a compromise between high efficiency performance and lower control complexity. To begin with, under traditional DAB modulations, modes attaining all devices zero voltage switching (ZVS) are frequently associated with high peak current stress or indirect power transfer, which can be avoided by OPDM. Second, under OPDM, all six typical operation modes can realize all semiconductors ZVS, where full-power-range ZVS can be realized simply to reduce switching loss. Third, under fixed transmission power, the minimum peak-to-peak current stress can be obtained through Lagrange multipler method. Peak current, rms current, and soft-switching characteristics under OPDM outperform conventional control methods. Eventually, a DAB prototype is established to verify the effectiveness of proposed OPDM method.
TL;DR: In this paper , the authors proposed a hybrid line-commutated converter by adding fully controlled devices to the conventional line-computated converter, which aims to achieve auxiliary commutation and forced commutation with the help of fully-controlled devices.
Abstract: Commutation failure is one of the most important factors threatening the safety of multi-infeed high voltage direct current systems. To mitigate commutation failure, we have proposed a novel hybrid line-commutated converter by adding fully controlled devices to the conventional line-commutated converter. It aims to achieve auxiliary commutation and forced commutation with the help of fully controlled devices. Based on the novel hybrid line-commutated converter topology, the study investigates how to select suitable fully controlled devices and how to design the appropriate parameters of the devices. First, this article studied the general characteristics of reverse-blocking devices, including reverse-blocking integrated gate-commutated thyristor (RB-IGCT) and asymmetrical IGCT with diode (including fast recovery diode and standard recovery diode). Then, the novel commutation principle is carefully proposed and analyzed. The comprehensive simulation results and comparison study of the novel commutation principle are conducted. Then, according to the proposed commutation principle, the voltage and current working stress of devices are illustrated. According to these, vital features of devices, including recovery speed, on-state voltage, current conduction ability, surge current, maximum turn-off current, robustness, and volume of devices, are carefully analyzed and compared. Related experiments are conducted to present the vital characteristics of devices in the equivalent operating conditions in converters. Finally, the advantages and disadvantages of RB-IGCT and IGCT with fast recovery diode and standard recovery diode are comprehensively presented, which offers valuable reference considered in engineering applications.
TL;DR: In this article , a coupled-inductor (CI)-based bidirectional dc-dc converter with a high voltage conversion ratio (VCR) and low voltage stress is proposed, where the topology can achieve high VCR by employing two CIs; moreover, the interleaved technique overcomes the defect of large current ripple in CI.
Abstract: In this article, a coupled-inductor (CI)-based bidirectional dc–dc converter with a high voltage conversion ratio (VCR) and low voltage stress is proposed. The topology can achieve high VCR by employing two CIs; moreover, the interleaved technique overcomes the defect of large current ripple in CI. A sensorless current balance between the two CIs is also realized without an auxiliary circuit and complex control method. The pulsewidth modulation plus phase-shift control is employed, where the duty cycle D is used to adjust the VCR, and the phase-shift angle ϕ is used to control the direction and amount of the transferred power. In addition, all switches can achieve soft-switching under a wide operation range. The steady-state analysis of the proposed converter is analyzed in detail, followed by comprehensive experimental verification under a 1-kW prototype.
TL;DR: In this paper , a cross-decoupling complex filtering-based position estimation method is investigated for the reduced capacitance interior permanent magnet synchronous motor drive system, where the film capacitor is applied to replace the large-volume electrolytic capacitor in motor drives.
Abstract: To extend the lifetime, improve the power density and reduce the system cost, the film capacitor is applied to replace the large-volume electrolytic capacitor in motor drives. As the dc-link voltage fluctuates periodically, the rotor position estimation error and operation stability are necessary to be concerned in the position sensorless control methods. A cross-decoupling complex filtering-based position estimation method is investigated for the reduced capacitance interior permanent magnet synchronous motor drive system. Harmonic components of the extended back electromotive force (EEMF) caused by the dc-link voltage fluctuation are analyzed to evaluate the additional rotor position error. A cross-decoupling complex filter realized by the multiple first-order complex filters with different center frequencies is designed to improve the position estimation precision. Harmonics of the EEMF are suppressed and the position error can be eliminated. The estimation precision and operation ability are improved. Experimental results are performed to verify the effectiveness of the proposed method.
TL;DR: In this article , a flexible third harmonic voltage modulation method was proposed to reduce the voltage ripple and capacitance of the switch-capacitor of a boost seven-level active neutral-point-clamped inverter.
Abstract: The switched-capacitor of boost seven-level active neutral-point-clamped inverter has the large voltage ripple due to its inherent long discharging interval. Aiming at reducing the switched-capacitor voltage ripple and subsequently the capacitance, this article proposes a flexible third harmonic voltage modulation method. In specific, the long discharging interval can be divided into short intervals or even avoided by flexibly regulating the amplitude and phase-angle of third harmonic voltage based on various modulation indexes and power factors. An offline particle swarm optimization algorithm is employed to find the corresponding optimal amplitude and phase-angle of third harmonic voltage, which will further be put into the online look-up table to simplify the real time implementation. Experimental results verified the performance of the proposed modulation method.
TL;DR: In this paper , a novel Bluetooth odometer (BOD)-aided smartphone-based vehicular navigation system for satellite-denied environments is investigated, where a wheel-mounted BOD is designed to measure rotational speed and send data to smartphones by Bluetooth transmission.
Abstract: This article investigates a novel Bluetooth odometer (BOD)-aided smartphone-based vehicular navigation system for satellite-denied environments. First, a wheel-mounted BOD is designed to measure rotational speed and send data to smartphones by Bluetooth transmission. Second, a nonlinear smartphone-based microelectromechanical system (MEMS) inertial measurement unit (IMU)/BOD error model is derived to solve the problem of azimuth divergence. Then, a position delay time model is proposed to compensate for the delay time of Bluetooth transmission. An Android app is developed to receive the BOD data from Bluetooth transmission, and the proposed BOD smartphone-based vehicular navigation algorithm provides positioning information in real time. In field tests, positioning accuracy reaches 0.38%D by using the proposed MEMS-IMU/BOD model. The designed scheme can be used as a low-cost and convenient solution for smartphone-based civilian vehicular autonomous navigation systems without changing the habits of drivers.
TL;DR: In this paper , the authors proposed a method for monitoring the chip branch failure due to bond wires fatigue in the multichip IGBT modules, which is based on the cumulative effect of the gate charge deviation when chip branch fails.
Abstract: The reliability of the multichip insulated gate bipolar transistor (IGBT) modules has been a concern. Condition monitoring is an effective approach to enhance reliability and improve the quality of customer service. This article proposes a method for monitoring the chip branch failure due to bond wires fatigue in the multichip IGBT modules. The idea is based on the cumulative effect of the gate charge deviation when the chip branch fails. By integrating the turn-on gate current of multiple switching cycles, the health state of multichip IGBT modules is characterized by the capacitor voltage as a health-sensitive parameter that can be extracted in the proposed monitoring circuit integrated into the gate driver. The capacitor voltage decreases significantly when the chip branch occurs due to bond wires fatigue. It is stable during sampling and has a strong immunity to junction temperature, collector current, and collector–emitter voltage. Besides, the method is nonintrusive and has the potential for real-time and online monitoring. These characteristics make the method reliable, easy to implement, and convenient for health status identification. The confirmatory experiment is carried out to verify the feasibility of the method.
TL;DR: In this article , the authors proposed the architecture and a graphical-based analysis for a digital asymmetric dual edge (ADE) carrier-based pulsewidth modulator (DPWM).
Abstract: This article proposes the architecture and a graphical-based analysis for a digital asymmetric dual edge (ADE) carrier-based pulsewidth modulator. In its digital version, it retains some advantages offered by the analog implementation. Indeed, in single-sampling operation, the phase delay introduced by this modulator is always less than or equal to the one obtained with the trailing-triangle edge (TTE) carrier. Moreover, by combining the advantages given by the ADE carrier and the double sampling of the modulating signal, it is possible to realize a digital modulator with a null phase delay. Since the proposed ADE-carrier-based digital pulsewidth modulator (DPWM) operates at a variable switching frequency, synchronization strategies between the carrier and the sampling instants may be required for some applications. Reliable synchronism correction architectures are, therefore, proposed and discussed. The developed model is validated through simulation and experimentally on a 27.5-kHz 9-kW single-phase voltage-source inverter case study. The experimental tests include a comparison with the DPWM architecture based on the TTE carrier.
TL;DR: In this paper , a hybrid DC circuit breakers (HDCCBs) topology that combines two types of power electronic devices in solid-state branches was proposed to meet the requirement of a large breaking capacity in dc grids.
Abstract: Hybrid DC circuit breakers (HDCCBs) have excellent performance in terms of breaking speed and low losses and have become the mainstream technology for dc fault isolation in dc grids. However, because of the breaking limitation of the solid-state branch in HdcCBs, the existing HdcCBs are still weak in breaking high current. Although the breaking ability can be improved by series and parallel devices, the cost will increase rapidly, and it is very difficult to share current by paralleling a single type of device. This article proposes a novel HdcCB topology that combines two types of power electronic devices in solid-state branches to meet the requirement of a large breaking capacity in dc grids. The structure and breaking principles of this novel topology, which aims to break high current, are introduced. The design methods of the key parameters are presented. Then, the current breaking ability of the novel topology is verified by developing a prototype completing a 10 kV/60 kA breaking test in 3 ms. Finally, this novel topology is compared with other dc circuit breakers at the same breaking level, which shows that this novel topology has obvious advantages in cost and volume with fewer devices.
TL;DR: In this paper , an injection amplitude regulator based on terminal sliding-mode control is proposed for low-speed position-sensorless switched reluctance motor (SRM) drives with the reduced induced current.
Abstract: This article proposes a new pulse injection scheme for low-speed position-sensorless switched reluctance motor (SRM) drives with the reduced induced current. Conventional injection methods utilize a constant injection amplitude for position estimation; however, the induced current in idle phases nonlinearly varies with the rotor position and has significant magnitude. It results in large negative torque and degrades the control performance. To mitigate this problem, an injection amplitude regulator based on terminal sliding-mode control is put forward. The amplitude of pulse voltages is adjusted online through a nonlinear control law, and the induced current can be maintained at a minimal level over the whole idle-phase period. Moreover, the adverse impacts of motor parameter uncertainties are eliminated. As a result, the proposed scheme does not require SRM's magnetic characteristics and is easy to implement. The effectiveness was experimentally validated on a three-phase 12/8 SRM setup with comparisons of the conventional method.
TL;DR: In this paper , the authors proposed a nonintrusive charging safety intelligent diagnosis scheme on the inputted power grid side, where more than 150, 000 charging records were collected from the grid side and various charging current patterns were formally identified according to the working principles of different batteries, charging modes and user behaviors.
Abstract: The widespread penetration of electric bicycles (E-bicycles) raises numerous charging safety concerns. However, online diagnosis of charging safety for E-bicycles remains challenging due to the limited data and involvement of multiple factors, such as battery, charger, charging mode, and user behavior. To overcome this difficulty and promote charging safety, this article proposes a nonintrusive charging safety intelligent diagnosis scheme on the inputted power grid side. First, more than 150 000 charging records are collected from the grid side, and various charging current patterns are formally identified according to the working principles of different batteries, charging modes, and user behaviors. Then, on the basis of longest similar substring (LSS), an improved dynamic time warping (DTW) model, referred to as LSS-DTW, is established to efficiently identify the charging current profile similarities and meanwhile restrict the overregularization of DTW. By this manner, the abnormal charging processes can be accurately identified. Experimental results reveal that the built LSS-DTW model can distinguish the unsafe charging processes online, and achieve the average identification precision, recall, and F1-score of 94%. Furthermore, the proposed algorithm can be extended to similar charging safety identifications in electric vehicles and other battery-powered systems and provides early warnings to avoid catastrophic consequences.
TL;DR: In this paper , the authors present a framework for systematic, stable and passive, dynamical balancing and locomotion control of flexible-joint bipedal robots with contacts, enabling the use of full-state feedback terms to increase both link tracking and oscillation suppression performance.
Abstract: This article presents a framework for systematic, stable and passive, dynamical balancing and locomotion control of flexible-joint bipedal robots. In order to achieve stability/passivity of the full flexible-joint, floating-base model with contacts, several novel control designs are proposed, whose ability to guarantee regulation and tracking stability is mathematically and practically demonstrated. The proposed designs enable usage of full-state feedback terms, thereby increasing both link tracking and oscillation suppression performance. These constitute the only control schemes reported in the literature, which are capable of asymptotically stabilizing flexible-joint, floating-base systems with contacts, during trajectory-tracking tasks. Moreover, a novel linear quadratic regulator (LQR) tuning approach is proposed, which permits the creation of models characterized by distinct kinetic chain and impedance combinations. Stable switching between these gain sets is guaranteed, as it is demonstrated that the proposed controllers enable unconstrained and stable, variable impedance control (VIC). The proposed control methods are corroborated through practical, balancing and locomotion experiments on the COmpliant huMANoid, as well as via dynamical simulations; these results demonstrate stability maintenance during tracking and VIC tasks. The ability to stably modulate a legged robot's active impedances could enable closer replication of biologically inspired behaviors.
TL;DR: In this paper , the authors proposed a novel structure for a four-switch three-phase inverter with the ability of creating a null vector, which utilizes a symmetrical quasi-Z-source network and generates zero output voltage during shoot-through state, similar to the null vector in the conventional six-switch inverter.
Abstract: In this article, a novel structure for a four-switch three-phase inverter with the ability of creating a null vector is proposed. This structure utilizes a symmetrical quasi-Z-source network and generates zero output voltage during the shoot-through state, which is similar to the null vector in the conventional six-switch inverter. This vector is used for the remaining time for each switching period. This means that the proposed structure has several advantages over the conventional four-switch inverter, in which two active vectors with opposite directions are necessary for synthesizing a null vector. These two vectors increase the switching losses due to the current circulation through these active states. Moreover, the number of switching states increases because of applying two opposite vectors. However, this problem does not exist in the proposed topology. To decrease the output current distortion and to minimize the number of switching events per each cycle, a new switching pattern is proposed, too. Also, fluctuations of the two split capacitors in the dc-link are considered in the closed-loop modulation method, which balances the output voltages and decreases current THD by 0.7%. To validate the proposed topology and the given pulsewidth modulation approach, its mathematical analyses are given here. Also, simulations and experimental verification have been performed on a 1-kW prototype inverter.
TL;DR: In this article , a distributed consensus filtering scheme, consisting of an optimal filter, a separated damping term, and a consensus tuning parameter, is considered through exchanging prior estimates among neighboring nodes, to achieve the cohesiveness among local estimates together with robust optimal estimation performance.
Abstract: This article presents a novel way of distributed consensus filtering with enhanced robustness over wireless sensor networks, where bounded-power disturbances related to modeling uncertainty and white Gaussian noises are included. Sensors are assumed to receive local observations and transmit them to their neighbors through lossy links. A distributed consensus filtering scheme, consisting of an optimal filter, a separated damping term, and a consensus tuning parameter, is considered through exchanging prior estimates among neighboring nodes, to achieve the cohesiveness among local estimates together with robust optimal estimation performance. A sufficient and necessary condition is conducted for determining the consensus parameter, leading to a nonconservative design way. Finally, to show the effectiveness of the presented results, an experiment of target speed tracking is included.
TL;DR: In this paper , a half-bridge module of a 650 V, 150 A enhancement-mode gallium-nitride power transistor is presented, which consists of the device chips interconnected between a printed circuit board and a direct-bonded copper substrate.
Abstract: Because of their fast-switching speed and small die size, gallium-nitride high electron mobility transistors are challenging to package for low parasitic inductance and high heat dissipation in power electronics applications. In this article, a packaging technique was developed for making half-bridge modules of a 650 V, 150 A enhancement-mode gallium-nitride power transistor. The package consists of the device chips interconnected between a printed circuit board and an aluminum-nitride direct-bonded copper substrate. The dice are bonded on the insulated ceramic substrate by silver-sintering to ensure high thermal performance and joint reliability. The source, drain, and gate pads are connected by silver-sintering gold-plated pins or silver rods, which are aligned by holes or grooves in the circuit board. For electrical insulation and mechanical robustness, the space surrounding the device is filled by injecting and curing an underfill polymer. Electrical and thermal simulations of the package show that the half-bridge module has a 1.122 nH power-loop inductance, and 0.099 °C/W junction-to-case thermal resistance. Packages of the half-bridge module were fabricated, and their static and dynamic performances were characterized.
TL;DR: In this paper , the authors investigated the internal thermal imbalance among paralleling chips and evaluated the impact on temperature distribution in field application using a new test algorithm with a purposely designed module sample, while the latter is achieved via an advanced electrothermal simulation from chip level to system level.
Abstract: In a high-power semiconductor power module where multiple chips are populated in parallel, the thermal imbalance problem arises. In this article, the next-generation standard high-voltage insulated-gate bipolar transistor module for high-speed railcar traction is investigated to characterize the internal thermal imbalance among paralleling chips and evaluate the impact on temperature distribution in field application. The former is accomplished by a new test algorithm with a purposely designed module sample, while the latter is achieved via an advanced electro-thermal simulation from chip level to system level. The experimentally verified thermal network among paralleling chips reveals the multiple reasons for the thermal imbalance. A comparison between the simulation and experimental results regarding the paralleling chips’ power-cycling scenario helps to confirm the effectiveness of the chip model, the thermal network, and the electro-thermal simulation approach. A further electro-thermal simulation shows that the module internal thermal imbalance can lead to significant junction temperature discrepancy among paralleling chips in traction inverter applications, which should be taken into consideration for the long-term reliability assessment.