Download Theorie examen GEA januari 2016 Prof Melkebeek

Theorie examen GEA januari 2016 ­ Prof Melkebeek ●
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Discuss third harmonic injection with three phase PWM. Discuss multi­stack stepping motor. Explain homopolar and heteropolar type. Discuss two and three level modulation for a single phase full­bridge PWM inverter. (differences in modulation, harmonics, …) Discuss space vector modulation.Bijvraag: meer harmonischen dan in natural sampled pwm? Voltage source inverter give and comment voltage, fundamental amplitude of wye and delta connection, space vector representation AC single phase commutation and difference with DC AC chopping of 3 phase inductance Characteristics of small DC machines. (Series excitation and permant magnet) Explain ideal sinusoidal current supply of IM, neglect main field saturation. What are the main influences when including saturation? How can it be modelled explain shortly, mathematical derivation is not necessary. AC commutator machine: EMF of motion, Transformer EMF and Torque Vector control and apply it to synchronous machine Single phase AC chopping of an inductance Give and Discuss the converter scheme for Switched Reluctance Machines Behaviour of IM with symmetric voltage deviations with voltage supply from the grid. Why are unsymmetric deviations that dangerous for our machine? Behaviour of SM at symmetric voltage variations with voltage supply from the grid. Why are asymmetric voltage deviations so dangerous for the machine? Explain direct and indirect method for field orientation of an IM. Apply the results of chopping a 3 phase inductance with an AC chopper to an IM CSI + SM with salient poles, is it possible to derive an equivalent scheme? Hold the DC voltage and the internal angle (psi) constant. What do you need to do practically to do this? Can you derive an equivalent reduced scheme to obtain the characteristics CSI current supply on IM ultrasone motor CSI with SM (smooth rotor): Derive an equivalent scheme. Draw the phasor diagram and derive the characteristics. Draw an reduced scheme using the characteristics. How is the control of the angle done practically? (gamma influences I_m). Extra: Draw the torque­speed characteristic. (linear). Discuss flux control of ‘Direct Torque Control’ (DTC). Discuss the fundamental harmonic equivalent scheme for voltage source inverter Give the energy conversion in switched reluctance motor based on flux­current characteristic (for a generator!). Explain how would you do current control. synchronous machine with permanent magnet excitation: Electromagnetic behaviour + torque. If we want to use the well­known formula’s for DC excitation, how can you transform the PM excitation in a equivalent DC excitation ●
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apply CSI fundament harmonic scheme to an induction machine (he wanted CSI+induction machine equivalent schemes..., and also the characteristics for a current­supplied induction machine) Discuss the dynamic characteristics of stepping motors Apply the formulas of AC chopper on the case of a 3­phase induction machine Discuss how we can use a variable voltage (like an AC chopper) to get ‘speed control’ in a broad range for a two­phase induction machine Explain naturally sampled and regularly sampled PWM. Discuss the harmonic content for both and the differences. Also discuss the influence of the carrier wave on the harmonic content. Extra: why is sawtooth still in use if it’s worse? (easier analog implementation)