View 4 excerpts, cites background. Input impedance of grid-connected converters with programmable harmonic resistance. Power factor correction converters with a programmable harmonic input impedance can be used to reduce the harmonic distortion in the utility grid. Whereas previously proposed controllers tried to … Expand. Power Conversion System PCS is the critical interface connecting energy storage devices and the utility grid. View 1 excerpt, cites methods.
Traditional design of the current loop controller in a single-phase power factor correction boost converter is not suitable for applications with higher line frequencies up to Hz because of the … Expand. View 3 excerpts, cites methods, background and results.
This paper presents a comparative evaluation of five topologies of single-phase AC-DC boost converters having power factor correction PFC.
These converter topologies are evaluated on the basis of … Expand. View 1 excerpt, cites background. Input impedance and current feedforward control for leading-lagging phase admittance cancellation in the AC-DC boost converter. This paper introduces an input impedance and current IIC feedforward control with leading-lagging phase admittance cancellation LLPAC for ac-dc boost converter applications requiring higher … Expand.
This paper presents a d-q-0 frame average model for multiple single-phase power-factor-correction PFC converters. The model is based on a three-phase four-wire load of equivalent per-phase PFC … Expand. Common mode impedance of modern embedded networks with power electronics converters.
This paper studies the common mode impedance of DC-DC converter in an embedded network. The frequency range of interest starts from few Hz up to tens of MHz. The low frequencies may be helpful for … Expand. Demystifying zero-crossing distortion in single-phase PFC converters. Proceedings Cat. Input current distortion in the vicinity of input voltage zero crossing in single-phase power factor corrected PFC AC-DC converters is analyzed in this paper.
The key result includes a new model … Expand. Highly Influential. View 6 excerpts, references methods and background. On the zero-crossing distortion in single-phase PFC converters. Input current distortion in the vicinity of input voltage zero crossings of boost single-phase power factor corrected PFC ac-dc converters is studied in this paper. Here, V s is the typical input voltage, AI, is the estimated inductor ripple current, and f s is the switching frequency.
Inductor ripple current can be found by Equation 8. In Equation 8. AV d is the desired output voltage ripple, which can be found as given in Equation 8. The gain is selected considering root locus, settling time, phase margin, and gain margin.
A time-domain simulation is conducted to verify the controller performance, and the results are presented in Figure 8. A DC-link capacitance for a small system with two units can be expressed by Equation 8. Consequently, the DC-link capacitance for n number of parallel units of systems can be found by Equation 8.
In addition, an industrial scale of DC grids, loads and sources are connected via long DC cable with higher inductance values. The characteristic impedance of the DC line can be obtained as Equation 8. This cable inductance induces resonance with DC link capacitance, and the resonance could propagate towards the power electronic devices or network or in both [13]. Three methods, namely, impedance analysis, time-domain simulation, and FFT analysis can be used for DC grid stability assessment; each of them has its own merits and demerits [7].
This section will briefly discuss the pros and cons of these three methodologies. Middlebrook et al. This theory has been extensively used to assess the small-signal stability SSS of an interconnected system since the mid 90s [15].
This method is also useful to check the SSS of power electronic PE -based power systems, and it could examine the whole system in accordance with the input and output features of its each and every subsystem [7].
In impedance analysis, a system splits into two sides first. Then, the output and input impedances are extracted, respectively, from the source and load subsystem of the particular system. Finally, the ratio of these two impedances is applied to find out the system stability. If the curve is far away from -1,0 point, then it is considered as a stable system. The system is deemed unstable when the curve cross or touch -1,0 point. In a nutshell, there are some specific advantages of impedance analysis over the other methods.
Studied analytical expression of the large and multi-converter DCMG could be obtained by impedance analysis. Moreover, it is possible to detect harmonic oscillation which is potentially originated from PE devices by impedance analysis. In this chapter, three different topologies have been considered, and under all topologies, the boost converter has been placed in the source side, whereas buck converter has been placed in the load side. Hence, the output impedances from the boost converter and the input impedances from the buck converter have been estimated.
The output impedance of the investigated boost converter can be expressed as Equation 8. For example, the motors used in driving electric automobiles require much higher voltages, in the region of V, than could be supplied by a battery alone. Even if banks of batteries were used, the extra weight and space taken up would be too great to be practical.
The answer to this problem is to use fewer batteries and to boost the available DC voltage to the required level by using a boost converter. Another problem with batteries, large or small, is that their output voltage varies as the available charge is used up, and at some point the battery voltage becomes too low to power the circuit being supplied.
However, if this low output level can be boosted back up to a useful level again, by using a boost converter, the life of the battery can be extended. The DC input to a boost converter can be from many sources as well as batteries, such as rectified AC from the mains supply, or DC from solar panels, fuel cells, dynamos and DC generators. However, in this example the switching transistor is a power MOSFET , both Bipolar power transistors and MOSFETs are used in power switching, the choice being determined by the current, voltage, switching speed and cost considerations.
The rest of the components are the same as those used in the buck converter illustrated in Fig. Fig 3. Therefore a current flows between the positive and negative supply terminals through L1, which stores energy in its magnetic field.
There is virtually no current flowing in the remainder of the circuit as the combination of D1, C1 and the load represent a much higher impedance than the path directly through the heavily conducting MOSFET. This results in two voltages, the supply voltage V IN and the back e.
V L across L1 in series with each other. Although the charge C1 drains away through the load during this period, C1 is recharged each time the MOSFET switches off, so maintaining an almost steady output voltage across the load.
Because the output voltage is dependent on the duty cycle, it is important that this is accurately controlled.
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