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In response to climate change, governments around the world have committed to reducing greenhouse gas emissions, which contribute to global warming, through the energy transition from fossil fuels to renewable energy sources and electrification of transportation. This article outlines the design procedure for the electrification of a railway vehicle used for maintenance services on the rail network. The proposed methodology consists of the design of both an all-electric propulsion system and storage system with the aim of zero emissions when the vehicle is operating in tunnels and to minimise noise during maintenance services in cities. After highlighting the characteristics of the railway vehicle under consideration, a simulation model of the propulsion and generation system was developed in order to calculate the energy consumption of the entire railway system. Finally, experimental tests carried out on the prototype proved the effectiveness of the design procedure adopted and the proposed mathematical model, showing a good matching with the simulated results. [ABSTRACT FROM AUTHOR]

The H-bridge-based multilevel active rectifier is an attractive topology that allows feeding of multiple dc loads. The main control problem is to manage n + 1 state variables (one current plus n dc voltages) with only n switching functions. In this paper, three PI-based solutions are discussed, and the tuning of the best solution is addressed in case resonant controllers are used instead of classical integrators. Moreover, practical problems such as the implementation and the influence of phase-locked-loop systems and of analog filters (first order and Butterworth) on the measurements are discussed. Index Terms--Active rectifier, digital control, multilevel converter.

In this paper, a new low-frequency predictive current control is proposed for a single-phase cascaded H-bridge multilevel rectifier. The control method has been fully investigated with theoretical analysis, simulation, and experiments on a laboratory prototype with five series-connected H-bridges. However, the analysis and technique are valid for any general N-level structure. The simulations and experimental results presented demonstrate the excellent performance of the predictive control in terms of ac current waveform quality, power factor, and reduced switching frequency of each bridge, in comparison to traditional control schemes. Index Terms--Active rectifiers, multilevel converters, predictive control, pulsewidth modulation (PWM).

This paper deals with the control of a multilevel n-H-bridges front-end rectifier. This topology allows n distinct dc buses to be fed by the same ac source offering a high loading flexibility suitable for traction applications as well as for industrial automation plants. However, this flexibility can lead the system to instability if the dc buses operate at different voltage levels and with unbalanced loads. Thus, linear controllers, designed on the basis of the small-signal linearization, are not effective any longer and stability can not be ensured as large-signal disturbances occur. The use of a passivity-based control (PBC) designed via energy considerations and without small-signal linearization properly fits stability problems related to this type of converter. The system has been split into n subsystems via energy considerations in order to achieve the separate control of each dc bus and its stability in case of load changes or disturbances generated by other buses. Then, a set of n passivity-based controllers (one for each subsystem) is adopted: the controllers are linked using dynamical parameters computed through energy balance equations. Hence, the system dc buses are independent and stable as experimental results demonstrate. Index Terms--Digital control, multilevel systems, rectifiers.

Power-quality monitoring is a very complex task and recently it is assuming a growing importance because of the large diffusion of nonlinear and time-varying single-phase and three-phase loads and their interactions with the power supply system. A set of two indexes capable of evaluating the power quality at the point of common coupling (PCC) in terms of harmonic distortion and unbalance is proposed in this paper. By means of these new performance parameters, which are based on voltage and current waveform measurements at the PCC, it is possible not only to evaluate separately unbalance and distortion, but also to localize polluting loads and separate the responsibilities of distributors and customers. Numerical simulations and experimental tests prove the effectiveness of the presented indexes and their low sensitivity to the network voltage conditions compared with the traditional ones. Index Terms--Power quality, power system harmonics.

This paper focuses on the design of a controller for a high-voltage high-power single-phase active rectifier, designed for, but not limited to, traction field applications. The rectifier should absorb current with low harmonic content to reduce the environmental electromagnetic pollution and to eliminate the disturbances to the on-board communication equipment. In addition, it should allow the elimination of the heavy and bulky transformer, reducing encumbrance and cost. A multilevel H-bridge single-phase configuration has been chosen and the design has been fully investigated with the help of theoretical analysis, simulations, and experiments. Index Terms--Active rectifier, digital control, multilevel converter.

The control of a single-phase multilevel H-bridge rectifier suitable for traction applications is considered. Such a converter often presents instability problems making difficult its design and uncertain its behavior. In this paper the use of a passivity-based controller is experimentally investigated. Such a controller achieves stability, unity power factor, good balancing between the two dc links, and satisfactory behavior even in the presence of load changes. A right choice of the damping parameters allows the fulfilling of system requirements in terms of dc-link voltage error and grid current distortion. Index Terms--Adaptive control, digital control, multilevel system, nonlinear control, power factor, pulsewidth modulation (PWM), rectifiers.

The cascaded H-bridge converter (CHB) is a very suitable solution with inherent modularity for many applications such as flexible ac transmission systems and motor drives. In this article, the discontinuous pulsewidth modulation (DPWM) by clamping some power cells is used in the CHB because it permits to reduce the switching losses in the power devices. However, this provokes a high harmonic distortion (basebands and sidebands harmonics) in the CHB output voltage compared with the quality obtained avoiding to clamp cells, just applying the conventional phase-shifted PWM (PS-PWM) technique. This has been studied for the three-cell CHB topology but the extension for an N-cell CHB with several clamped cells is a challenge that is addressed in this article. A generalized CHB harmonic voltage analysis applying the DPWM method is presented considering multiple clamped cells. The harmonic distortion mitigation target can be decoupled into two objectives. The proposed method cleverly groups the cells (one clamped + one or two nonclamped cells) to mitigate the basebands harmonic distortion. Simultaneously, a variable-angle PS-PWM technique is applied to the CHB in order to mitigate the sidebands harmonics content. Experimental results demonstrate the good performance of the proposed method. [ABSTRACT FROM AUTHOR]