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This paper presents comprehensive ripple analyses for generalised multiphase switch-tapped-inductor boost converters. Input and output currents and voltage ripple expressions are derived for converters with any number, N, of phases. It is shown that due to interleaving, highest possible total input- and output-side ripple changes very little as the number of phases and hence total power increases...
The three-phase quasi-Z-source AC–DC converter possesses many attractive attributes for applications with wide AC input variations, such as variable speed wind generator applications. This is due to its buck–boost capability, high input power factor, low output ripple and low rating of components. Detailed steady-state and small-signal models of the converter are derived using circuit averaging and...
When planning HVDC connection into an area, many possible receiving end point could be available. To analyze all of them can be laborious and time-consuming. On the other hand, questions may arise as to why some were not considered, thus threatening the validity of the studies. In this paper, preliminary work on comparing loadflow studies to assess receiving end points is presented. Loadflow studies...
High density high switching frequency power converter conducted EMC had been analysed, modelling the noise source and noise path, while providing accurate conducted EMC noise levels comparable to accredited noise measurements up to 100 MHz. The military specified DC-DC converters are generally applicable, spanning from 100 W handheld power managers up to 2 kW DC-DC battery chargers. A Buck topology...
High density high switching frequency power converter conducted EMC had been analysed, modelling the noise source and noise path, while providing accurate conducted EMC noise limits comparable to accredited noise measurements up to 100 MHz. The military specified DC-DC converters are applicable, spanning from 100 W handheld power managers up to 2 kW DC-DC battery chargers. The Step-Down converter,...
An extended pre-compliance measurement setup has been created in the development laboratory to measure and diagnose conducted EMI up to 100 MHz without the use of a spectrum analyser. A dual compact Line Impedance Stabilisation Network (LISN) had been designed, assembled and validated in an accredited EMC laboratory. It was designed for high density military DC-DC power converters with input voltages...
Switched-capacitor multilevel DC-DC converters for interfacing DC-buses with separate grounds have been proposed recently. Including a very small inductor in series with the low-voltage DC-bus or source, significantly reduces semiconductor switching losses. However, past investigations have not tried to establish how converter performance depends on the sizes of both clamping and voltage-divider capacitors...
Multilevel switched-capacitor DC-DC converters have been proposed for applications that require interfacing two DC-buses or sources. High-voltage DC-bus in general is specified to be an integer multiple that of the low-voltage side. Low efficiency, bulky capacitor banks and unequal voltage sharing have been identified as some of the shortcomings of these converter topologies. This paper will show...
Underground mining activities in South Africa depend on battery fed underground locomotives to haul ore. The batteries are predominantly lead-acid and have to be charged periodically. At the moment, most of the battery chargers in use in South African mines are based on ferroresonant or transductor charger technology. At the same time, the charging algorithms in use are time based and in general without...
Capacitor-switching operations found in magnetic-less DC-DC converters lead to significant capacitor power loss while capacitor voltage unbalance leads to high peak currents in the capacitors and switches. Power loss leads to premature failure of capacitors and is inversely proportional to both capacitance and switching frequency. A given reduction in losses then requires a corresponding increase...
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