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The total harmonic distortion (THD) of a waveform is a standard way to quantify its deviation from a sinusoid. In three-phase systems, we are interested in minimizing 3THD: the component of THD produced by odd nontriplen harmonics. However, its definition involves an infinite sum, making it difficult to evaluate and analyze. This paper solves the problem of finding equivalent closed-form expressions for the 3THD of a staircase waveform. In particular, two expressions are rigorously derived, which reveal 3THD to be a piecewise differentiable function. One expression is shorter but describes the pieces implicitly. The other is longer but describes the pieces explicitly. We minimize 3THD using the closed-form expression and provide a comparison with previous techniques. Finally, we provide experimental results that show close agreement with the theoretical results. [ABSTRACT FROM AUTHOR]

A network of fast-charging stations is of great importance for widespread adoption of electric vehicles (EV) if the so-called range anxiety issue is to be resolved. As with petrol stations, we expect that multiple chargers will be co-located to form charging stations. This layout allows for the fast-charging station to make use of a common rectifier stage and several dc/dc stages to charge multiple EVs. This paper builds on our previous work where we proposed a novel dc-side filter for the 12-pulse rectifier and investigated the power profile for a MW fast-charging station. In this paper, we propose a novel control approach for the filter, based on the virtual resistor injection, which results in further reduction in dc ripple, ac-side harmonics, and filter VA ratings. We also demonstrate that, with the proposed topology and control, the filter stage can be used as dc-side energy storage system. [ABSTRACT FROM AUTHOR]

The 12-pulse rectifier is often used to supply high-power industrial loads. Its ability to effectively and cheaply mitigate the harmonics on the ac side has ensured its dominance in the industry even as active front ends become cheaper and more reliable. Despite its many benefits, the 12-pulse rectifier is not able to reduce the ac-side harmonics to a level acceptable by the pertinent IEEE standards without additional filtering. In this paper, we outline a novel method to profile the rectifier output current to be triangular which results in low ac-side harmonics. The novelty in the proposed approach is that we exploit the dc-side filter design to minimize the volt-amperes (VA) rating of the current source used to profile the dc-side rectifier current. Additional benefits of the proposed method include lower VA rating of the dc filter, simple integration of dc energy storage, and effective ac harmonic control even when the initial rectifier current is discontinuous. [ABSTRACT FROM PUBLISHER]

Inductive power transfer (IPT) is commonly used to transmit power from an extended loop (track) to a number of galvanically isolated movable pick-ups. To maximize the power transfer and minimize converter requirements, various compensation circuits have been proposed for both the track (primary) and the pick-up (secondary). This paper investigates the suitability of the LCC series–parallel compensation for IPT primary design. A new compensation-circuit design procedure is proposed that considers high-order current harmonics and results in inverter zero-current switching. The proposed compensation is compared with the classical compensation designed for zero phase angle between the inverter voltage and current fundamental components. Expressions for the bifurcation boundary, voltampere rating of reactive-compensation elements, and the current at the moment of switching are derived and analyzed. Analytical results are verified both via PSpice simulations and experimentally using a 1-hp MOSFET-based prototype. [ABSTRACT FROM PUBLISHER]