TEST+3+++ Eapow 3B26+April+2012 PDF

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TEST 3 1.

1.1 1.2 1.3 1.4

2.

2.1 2.2 2.3 2.4

TEST 3 1.

1.1 1.2 1.3 1.4

2.

2.1 2.2 2.3 2.4

EAPOW3B

26 April 2012

A single phase inverter is to be designed to supply a 220 V, 50 Hz sine wave to a load. Fourier analysis has to be done to determine the magnitude of the supply voltage in order to deliver a 220 V rms at the fundamental frequency (50 Hz in this case). The control method proposed is 180˚ control. The higher harmonics are to be removed by means of a resonant arm filter. Sketch a basic topology of the inverter. Sketch waveforms for the control signals, load voltage and switching function. Derive an expression for the Fourier series of the output waveform. Determine the magnitude of the supply voltage to provide a 220 V rms at the fundamental frequency.

An MOSFET dissipating 20 W is mounted on a heat sink. Worst case ambient temperature where the equipment is to be installed is estimated at 50 °C. Thermal resistance from junction to case is 0,5 °C/W and between case and heat sink it is 0,5 °C/W when thermal compound is used between the case and sink. Sketch the thermal equivalent circuit. Calculate the thermal resistance of the heat sink for industrial applications. Calculate the thermal resistance of the heat sink for military applications. Calculate the thermal resistance of the heat sink for commercial applications.

EAPOW3B

(1) (4) (5) (5) [15]

(1) (3) (3) (3) [10] ___ /25/

26 April 2012

A single phase inverter is to be designed to supply a 220 V, 50 Hz sine wave to a load. Fourier analysis has to be done to determine the magnitude of the supply voltage in order to deliver a 220 V rms at the fundamental frequency (50 Hz in this case). The control method proposed is 180˚ control. The higher harmonics are to be removed by means of a resonant arm filter. Sketch a basic topology of the inverter. Sketch waveforms for the control signals, load voltage and switching function. Derive an expression for the Fourier series of the output waveform. Determine the magnitude of the supply voltage to provide a 220 V rms at the fundamental frequency.

An MOSFET dissipating 20 W is mounted on a heat sink. Worst case ambient temperature where the equipment is to be installed is estimated at 50 °C. Thermal resistance from junction to case is 0,5 °C/W and between case and heat sink it is 0,5 °C/W when thermal compound is used between the case and sink. Sketch the thermal equivalent circuit. Calculate the thermal resistance of the heat sink for industrial applications. Calculate the thermal resistance of the heat sink for military applications. Calculate the thermal resistance of the heat sink for commercial applications.

(1) (4) (5) (5) [15]

(1) (3) (3) (3) [10] ___ /25/...