Zero Voltage Switching Case Study

Amazing Essays
CHAPTER1
INTRODUCTION TO ZVT
1.1 What is ZVT?
Zero voltage switching can best be defined as conventional square wave power conversion during the switch’s on-time with “resonant” switching transitions. For the most part, it can be considered as square wave power utilizing a constant off-time control which varies the conversion frequency, or on-time to maintain regulation of the output voltage. For a given unit of time, this method is similar to fixed frequency conversion which uses an adjustable duty cycle, as shown in Fig. 1. Fig1.1 Zero voltage switching
Regulation of the output voltage is accomplished by adjusting the effective duty cycle, performed by varying the
…show more content…
This snubber cell provides perfectly ZVT turn on and ZCT turn off together for the mainswitch of a converter by using only one quasi resonant circuitwithout an important increase in the cost and complexity of theconverter. New ZVT–ZCT–PWM converter equipped with the proposed snubber cell implements most the desirable featuresof both the ZVT and ZCT converters presented previously, and overcomes most the drawbacks of these converters. The steadystate operation of the new converter is analyzed in detail, and this theoretical analysis is verified exactly by a prototype of a1-kW and 100-kHz boost converter. In this thesis, a boost converter operating all the switching devices under Zero Voltage Transition is studied and a model converter which can supply a load of 250W is designed and is used in a PV energy system. In this converter topology, a part of the circuit resonates for a small portion of the switching cycle of the converter, known as the auxiliary circuit that enhances the soft transition from ON state to OFF state and vice versa, thus improving the converter efficiency by reducing the dominating portion of in losses i.e. the losses that occur due to hard transition of the switches. Due to reduced losses during switching transitions heating effect of MOSFETs is reduced and they have a longer life. The comparative study between the new topology and conventional hard switching converter is analyzed in terms of improvement of efficiency and reduction of switching

Related Documents

  • Decent Essays

    Power, as we know, consists of two components, active and reactive power. The total sum of active and reactive power is called as apparent power. Finally, we also specify what we might intuitively think of as the difference between apparent and real power, namely, reactive power. Reactive power is the component of power that oscillates back and forth through the lines, being exchanged between electric and magnetic fields and not getting dissipated. It is denoted by the symbol Q, and its magnitude is given by: Again, note how the equation converges for the resistive case where ø = 0 and sinø = 0, as there will be no reactive power at all.…

    • 1382 Words
    • 6 Pages
    Decent Essays
  • Decent Essays

    Ex. Consider a transmission line connected between load centre and generating station. We assume line is loss less and ignore line charging, then the power flow (P) is, P=V1V2 sin⁡(θ1-θ2)/X Where, X= transmission line reactance V1= sending end voltage V2= receiving end voltage Assume V1 and V2 are remain constant Power flow in the transmission line is obtained by the power injected throw power station. If…

    • 1664 Words
    • 7 Pages
    Decent Essays
  • Decent Essays

    Figure 4.9 Circuit diagram of boost converter employed in PV system The analysis is performed under the ideal condition. It is assumed that the load is pure resistive and impedance of the boost converter is neglected. The time period and duty cycle of the boost converter are denoted as D and T respectively. When the IGBT switch is in ON state, the output voltage is: Vpv. D.T; When the IGBT switch is in OFF state, the output voltage is: —(Vo- V p v).…

    • 1370 Words
    • 6 Pages
    Decent Essays
  • Decent Essays

    With the intention to simplify the analysis, it was assumed the current, independent of the direction, always will be conducted by the MOSFET channel, instead of the body diode. The MOSFET on-resistance is the only parasitic resistance considered in this analysis. However, all resistances in the loop (e.g. equivalent series resistance (ESR) of the capacitors and trace resistance) will assist the capacitor switching. In order to obtain a steady-state model, it is necessary to extract the equations of each conduction state.…

    • 1224 Words
    • 5 Pages
    Decent Essays
  • Decent Essays

    The thermal efficiency is defined by the relation For analyzing the Rankine cycle, it is helpful to think of efficiency as depending on the average temperature at which heat is supplied and the average temperature at which heat is rejected. Any changes that increase the average temperature at which heat is supplied or decrease the average temperature heat is rejected will increase the Rankine-cycle efficiency. In analyzing the ideal cycles in this chapter, the changes in kinetic and potential energies from one point in the cycle to another are neglected. In general, this is a reasonable assumption for the actual…

    • 766 Words
    • 4 Pages
    Decent Essays
  • Decent Essays

    But in Norton’s Theorem the equivalent circuit has a current source and a resistance in parallel with the load resistance (R_X). Continued on next page: HOW IS IT USED When using Norton’s Theorem the load resistance is removed and replaced with a short (wire) and points labeled A and B. The reason to label the points A and B is to show where the meter would measure the unknown voltage and current associated with the load resistance. Next the load resistor is placed into the Norton’s equivalent circuit. In addition to that, the equivalent circuit is where to solve for the Norton resistance (R_N) and the Norton current (I_N).…

    • 807 Words
    • 4 Pages
    Decent Essays
  • Decent Essays

    In the conventional IBC, the active switches are connected in parallel but in this converter two active switches are connected in series and a coupling capacitor is employed in the power path. The two active switches are driven with phase shift angle of 180° and the output voltage is regulated by adjusting the duty cycle at a fixed switching frequency. The proposed IBC operates at CCM, the current stress is low. The voltage stress across all active switches before turn-on or after turn-off, during the steady state is half of the input…

    • 1542 Words
    • 7 Pages
    Decent Essays
  • Decent Essays

    For the assigned study, cylindrical coordinates are used since the material used is a pipe. Assuming that the temperature is only a function of radius and that the system operates at steady state, Fourier’s law of heat conduction is re-expressed…

    • 1335 Words
    • 6 Pages
    Decent Essays
  • Decent Essays

    A unknown smoothing function is represented by the g(A_i ), and it is assumed to be constant across the pre- and posttest time periods (for further discussion of a smoothing parameter see Peng, 1999). The relationship between the assignment variable and the outcome variable during the pretest period are the foundation of this design, it allows for extrapolation beyond the assignment cut-off criterion in the posttest period (Wing and Cook,…

    • 1016 Words
    • 4 Pages
    Decent Essays
  • Decent Essays

    Which is reached by making r = 0. Therefore P_(L_MAX )= E^2/R_L with an ideal source. Thus for a completely resistive circuit the internal resistance of a DC source should be equal to zero for maximum power transfer to the load resistance. The derivation of the maximum power transfer theorem for resistive and non-linear impedance AC circuits. I – Phasor current (ωL or-1/ωC)_L and (ωL or-1/ωC)_r= X_L and X_r respectively I = (E_rms∠0°)/(Z+Z_r ) = (E_rms∠0°)/(r+R_L+j(X_r+X_L)) P_L= |I|^2 R_L =R_L/(〖(r+R_L)〗^2+〖(X+X_L)〗^2 ) 〖E_rms〗^2 2.1) The maximum power transfer when we have the choice to decide both the load resistance and reactance.…

    • 771 Words
    • 4 Pages
    Decent Essays