What is the role of capacitor in boost converter It provides the charge and for

What is the role of capacitor in boost converter it

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26) What is the role of capacitor in boost converter? 27) Mention about SOC and its methods. (Nov/Dec 2014) State of charge ( SOC ) is the equivalent of a fuel gauge for the battery pack in a battery electric vehicle (BEV), hybrid vehicle (HV), or plug-in hybrid electric vehicle (PHEV). The units of SOC are percentage points (0% = empty; 100% = full). SOC is normally used when discussing the current state of a battery in use. In general there are five methods to determine SOC indirectly . 1) chemical 2) voltage 3) current integration 4) Kalman filtering 5) pressure. 28) Specify about power conversion ratio. (Nov/Dec 2014) Power conversion ratio or Energy conversion efficiency (η) is the ratio between the useful output of an energy conversion machine and the input, in energy terms. The useful output may be electric power , mechanical work , or heat. Power conversion ratio = P out /P in
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29) Why Loop Compensation used in Buck Converter (May/June 2016) The modulator and the output filter (including the load resistance) create the forward plant of the buck converter. These are the two stages that generate a dc output voltage from the dc input voltage. In order to close the loop, the output voltage is compared to a voltage reference, the error is amplified, and that error is applied to the modulator as its control voltage input. As the output voltage approaches the reference voltage, the error produced becomes small, and the system reaches a point of equilibrium: a temporary increase in Vout creates a corresponding decrease in control voltage, which in turn drives the duty cycle of the modulator down, bringing the system back to a new point of equilibrium. In order for this linear system to be stable, the loop phase delay must be less than 360° while the loop gain is above unity [ |ALoop (s)|≥ 1, or 20log|ALoop (s) | ≥ 0 dB]. While the loop is stable for any phase shift less than 360°, a critically damped system (a reasonably fast loop response with minimal overshoot) will have a phase margin (defined as the difference between the actual loop phase delay and 360°) of about 60°. Any phase margin above zero degrees is technically stable, but lower values of phase margin are accompanied by more ringing in the loop after the loop is perturbed (by a change in Vin or Iout, for example). In power circuit design, 45° is often taken as a minimum goal for the phase margin. PART B
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