advertisement

TUTORIAL/ASSIGNMENT 3 1. A full-bridge inverter has a switching sequence that produces a square wave voltage across a series RL Load. The switching frequency is 50 Hz, Vdc = 100 V, R = 10 Ω, and L = 25 mH. Determine: (a) RMS value of the output voltage, Vrms (b) RMS value of the fundamental frequency component of the output voltage, V1,rms and the output current, I1,rms ∞ (c) RMS value of the harmonics of the output voltage, ∑V n n =2 ∞ (d) RMS value of the harmonics of the output current, ∑I n n =2 (e) Total harmonic distortion of the output voltage, THDV (f) Total harmonic distortion of the output current, THDI (g) The power absorbed by the load 2. A full-bridge inverter has a switching sequence that produces a quasi-square wave voltage across a series RL Load. The switching frequency is 50 Hz, Vdc = 100 V, R = 10 Ω, L = 25 mH and α = 30°. Determine: (a) RMS value of the output voltage, Vrms (b) RMS value of the fundamental frequency component of the output voltage, V1,rms and the output current, I1,rms ∞ (c) RMS value of the harmonics of the output voltage, ∑V n n =2 ∞ (d) RMS value of the harmonics of the output current, ∑I n n =2 (e) Total harmonic distortion of the output voltage, THDV (f) Total harmonic distortion of the output current, THDI (g) The power absorbed by the load 3. Design an inverter that will supply the series RL load of the previous examples (R =10 Ω and L = 25 mH) with a fundamental-frequency current amplitude of 10 A, but with a THD of less than 10 percent. A variable dc source is available. Hint: You need to find Vdc and THDI to meet the specifications. 4. The full-bridge inverter is used to produce a 50-Hz voltage across a series RL load using bipolar PWM. Vdc = 100 V, ma = 0.8, mf = 21, R = 10 Ω, L = 25 mH. Determine: (a) RMS value of the fundamental frequency component of the output voltage, V1,rms and the output current, I1,rms (b) THDI (c) The power absorbed by the load