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In this paper, the generic analysis and design of Zero-Voltage-Switching (ZVS) multi-phase AC/DC converters are proposed. With the Edge Aligned PWM (EA-PWM) scheme, all switches of ZVS multi-phase AC/DC converters can realize ZVS operation. Besides, the switching frequency is fixed and the auxiliary switch only operates once in each switching period. Its operation stages in a switching cycle are analyzed and a generic ZVS condition is derived. Based on the proposed theory, a ZVS two-stage three-phase photovoltaic (PV) inverter is investigated, which is regarded as a 5-phase converter. Its ZVS condition under different working conditions is discussed. Finally, a 10kW prototype with 150kHz switching frequency of the ZVS two-stage three-phase PV inverter is built and the experiment results are given to verify the analysis. In addition, the extension of the ZVS multi-phase converter in different applications is introduced.

Spatial architecture is a high-performance architecture that uses control flow graphs and data flow graphs as the computational model and producer/consumer models as the execution models. However, existing spatial architectures suffer from control flow handling challenges. Upon categorizing their PE execution models, we find that they lack autonomous, peer-to-peer, and temporally loosely-coupled control flow handling capability. This leads to limited performance in intensive control programs. A spatial architecture, Marionette, is proposed, with an explicit-designed control flow plane. The Control Flow Plane enables autonomous, peer-to-peer and temporally loosely-coupled control flow handling. The Proactive PE Configuration ensures timely and computation-overlapped configuration to improve handling Branch Divergence. The Agile PE Assignment enhance the pipeline performance of Imperfect Loops. We develop full stack of Marionette (ISA, compiler, simulator, RTL) and demonstrate that in a variety of challenging intensive control programs, compared to state-of-the-art spatial architectures, Marionette outperforms Softbrain, TIA, REVEL, and RipTide by geomean 2.88x, 3.38x, 1.55x, and 2.66x.

This paper proposes a novel zero-voltage-switching (ZVS) three-phase four-wire back-to-back (BTB) converter topology and its ZVS sinusoidal pulsewidth modulation (ZVS-SPWM) scheme. With the proposed ZVS-SPWM scheme, all the main switches in both the rectifier side and inverter side and the auxiliary switch can realize ZVS turn on with only one auxiliary circuit. In addition, the auxiliary switch only needs to operate once in each switching period, which can cut down an extra loss of the auxiliary circuit. The operation stage analysis is introduced, and the ZVS condition for the switches is derived. The ZVS BTB converter is investigated with respect to both balanced and unbalanced load conditions. In additon, the soft-switching parameter design guideline is discussed. Finally, the proposed ZVS BTB converter and its ZVS-SPWM scheme are verified on a 9-kW prototype with the SiC-MOSFET device.

A novel zero-voltage-switching (ZVS) three-phase T-type inverter and its control scheme are proposed, which can realize ZVS operation of all switches. The operation principle of the proposed ZVS T-type inverter is analyzed. Furthermore, the ZVS condition is derived and the voltage stress is analyzed. Finally, the proposed ZVS three-phase T-type inverter is verified by the simulation.

Fundamental of Edge Aligned PWM (EA-PWM) for soft-switching three-phase power converters is presented. It aligns all the high loss commutation instants of the converter bridges in a switching cycle at the same instant so that all the switches of the three-phase converter can realize zero-voltage-switching (ZVS) with the help of the resonant auxiliary circuit which operates once each switching cycle. EA-PWM scheme for ZVS active-clamping three-phase converter is introduced. ZVS condition and voltage stress of the converters is derived. EA-PWM can adapt to various modulation methods such as SPWM, Harmonic Injected SPWM, Continuous Pulse Width Modulation (CPWM), Discontinuous Pulse Width Modulation (DPWM), etc. The ZVS condition of three-phase CAC converter are discussed.

In recent years, modern tramcar has developed rapidly. The grooved rail is used widely in its main line track. However, at present, the main detection method of its geometric parameters of grooved rail is manual detection, with low working efficiency. Therefore, this paper proposes a set of dynamic detection system of grooved rail irregularity based on inertial reference method, which can realize the detection of grooved rail irregularity such as longitudinal irregularity, alignment irregularity, etc. On the basis of previous work, improvement & application of measuring longitudinal irregularity and alignment irregularity has been proposed. The key points of this improved algorithm are to put forward synthesized filtering algorithm based upon grooved rail's geometric features, which enhances the stability of the detect system; and use the frequency domain integration algorithm, which improves the accuracy of the detect system. Experiment verification shows that the dynamic detection system has the characteristics of high detection accuracy and splendid stability, which provides a new tool for dynamic detection of geometric parameters of grooved rail of modern tramcars.

In recent years, the construction of China’s rail transportation has grown rapidly. Whether it is an I-shaped track or a grooved-shaped track, the detection of track irregularities is mostly based on the inertial reference method or the string measurement method, but both methods are limited by the speed factor to varying degrees. This paper studies a comprehensive detection method based on fuzzy neural network that combines the inertial reference method with the four-point chord method. It can realize high-precision detection of speed fuzzy speed section (transition speed section), so as to achieve detection of full speed section, and overcome system errors caused by algorithm factors.

In recent years, modern trams have developed rapidly and groove rails are mainly used for tramway tracks. Whether their geometric parameters exceed the limit is related to the safety of train operation. In addition, the health of the grooved rail also affects the service life of the rail equipment. Therefore, track maintenance activities play an important role in maintaining the health of track equipment, extending its service life, and operating safety of railways. With the previous research, we have developed a rail inspection trolley based on the inertial reference method, and it can achieve high-precision detection of geometric parameters of groove rails. On this basis, this paper proposes a set of prediction algorithms based on RBF radial basis neural network. It can accurately predict the change trend of geometric parameters such as track gauge, abrasion, track longitudinal level irregularity and track direction, so as to further analyze the detection data and explore its inherent value, providing a more scientific basis for the preventive track maintenance.

In recent years, modern trams have developed rapidly and groove rails are mainly used for tramway tracks. However, there is less research on the wear detection of groove rails, and even fewer wear detection applications. With the help of the laser triangulation method, this paper developed a set of wear detection of modern tramway groove rails. Among them, a set of data filtering algorithms with self-adaptive function and combined with the geometric characteristics of the groove track are proposed to eliminate data interference points and smooth the data. At the same time, an error correction algorithm is used to correct the detection error angle caused by snake driving, vibration and sensor installation deviation. In addition, this paper also proposes a set of groove rails profile matching algorithms and wear calculation algorithms to achieve accurate measurement of the vertical wear, side wear and total wear of the grooved rail. Experimental verification shows that the wear detection algorithm has strong anti-interference ability and comprehensive data error correction ability.

At present, with the rapid development of trams, most of the tracks adopt groove rails. However, most of the methods for dynamic detection of geometric parameters of groove rails in the market adopt inertial reference method or three-point chord measurement method, whose requirement for the installation of sensors is high, selection of points is not reasonable enough and parameter accuracy is not high enough. In the thesis, a new dynamic detection algorithm for geometric parameters of groove rails based on the four-point chord measurement method and laser triangulation principle is developed which uses the laser triangulation principle to obtain the track contour data, so as to realize real-time data collection, improve data redundancy and solve the difficulties caused by sensor installation. In order to eliminate the errors caused by serpentine motion and vibration of the vehicle body, data processing is carried out by means of adaptive limiting filtering and segmented mean filtering. In order to improve the data accuracy of geometric parameters, the track longitudinal irregularity and alignment irregularity are obtained by four-point chord measurement. Experimental verification shows that this method solves the problem of difficult installation and distribution of the sensor in four-point chord measurement, improves the accuracy and stability of the system measurement and provides new ideas and methods for the detection of groove rail irregularity parameters.

Three-phase four-wire rectifiers with a balancing leg are often used as front-end converters in uninterruptible power supplies (UPS). The integration of minimum-voltage active-clamping (MVAC) to these rectifiers is proposed. With the proposed Zero-Voltage-Switching Sinusoidal PWM (ZVS-SPWM) scheme, ZVS operation for all power semiconductor devices of the rectifier are realized. The ZVS conditions under balanced and unbalanced load are derived. Then voltage and current stress of switching devices and auxiliary circuit are compared with the compound-active-clamping (CAC) three-phase four-wire rectifier. Finally, the proposed circuit and its control scheme are verified with a 10kW experiment prototype.

Universal zero-voltage-switching (ZVS) technique for multi-phase AC/DC converter is proposed. With the proposed technique, all switches of the multi-phase AC/DC converter can realize ZVS operation by using one auxiliary circuit. A ZVS-SPWM scheme for the multi-phase converter is introduced. The operation principle and the stage analysis are presented. Generic ZVS condition is derived according to the equivalent resonant circuits. Next, the design guideline of the resonant parameters is presented. Finally, a ZVS four-phase AC/DC converter called ZVS single-phase back-to-back (BTB) converter is investigated as an example and the prototype is set up to validate the proposed universal ZVS technique for the multi-phase converter.

An audio noise-free Uninterruptible Power Supply (UPS) with Zero-Voltage-Switching (ZVS) back-to- back (BTB) converter is proposed. Firstly its ZVS sinusoidal pulse width modulation (SPWM) scheme is introduced. Using the proposed ZVS-SPWM scheme, all the switches in both the rectifier side and inverter side as well as the auxiliary switch can realize ZVS turn-on with only one commonly shared auxiliary circuit. Besides, the auxiliary switch only needs to operate once in each switching period, which can reduce the extra loss caused by the auxiliary circuit. The ZVS conditions with respect to both balanced and unbalanced load situations are given. A resonant parameter design guideline and a low stray inductance bus bar design is introduced. Finally the proposed UPS system with ZVS BTB converter is verified on a 50kVA experimental prototype.