ECEN 5817 Resonant and Soft-Switching Techniques in Power Electronics 1 Lecture 19 2 ECEN, Lecture notes of Power Electronics

Download ECEN 5817 Resonant and Soft-Switching Techniques in Power Electronics 1 Lecture 19 2 ECEN and more Lecture notes Power Electronics in PDF only on Docsity! Fundamentals of Power Electronics 1 Chapter 19: Resonant Conversion • For both on-campus and CAETE students: A DVD of recorded lectures from Professor Erickson’s Spring ’06 class will be mailed to you sometime next week. These will not be available on the CAETE website CUAnywhere.colorado.edu • For on-campus students: You will not have access to this semesters recorded lectures on the CAETE website • For CAETE students: By popular request, scanned and e-mailed homework will be accepted provided the submissions meet the following requirements: • Black and white (no color, no grayscale) • 200 – 300 dpi • All problems scanned into ONE PDF file for the whole assignment • PDF file is easy to read, easy to open, and easy to print ECEN 5817 Housekeeping update Fundamentals of Power Electronics 2 Chapter 19: Resonant Conversion Chapter 19 Resonant Conversion Introduction 19.1 Sinusoidal analysis of resonant converters 19.2 Examples Series resonant converter Parallel resonant converter 19.3 Soft switching Zero current switching Zero voltage switching 19.4 Load-dependent properties of resonant converters 19.5 Exact characteristics of the series and parallel resonant converters Fundamentals of Power Electronics 5 Chapter 19: Resonant Conversion Conversion ratio M So we have shown that the conversion ratio of a resonant converter, having switch and rectifier networks as in previous slides, is equal to the magnitude of the tank network transfer function. This transfer function is evaluated with the tank loaded by the effective rectifier input resistance Re. Fundamentals of Power Electronics 6 Chapter 19: Resonant Conversion 19.2.2 Subharmonic modes of the SRC Example: excitation of tank by third harmonic of switching frequency Can now approximate vs(t) by its third harmonic: Result of analysis: Fundamentals of Power Electronics 7 Chapter 19: Resonant Conversion Subharmonic modes of SRC •Not often used - reduced switch utilization and decreased voltage conversion ratio •Still need to be aware their existence Fundamentals of Power Electronics 10 Chapter 19: Resonant Conversion Construction of Zi – Resonant (high Q) case C = 0.1 μF, L = 1 mH, Re = 10 Ω Fundamentals of Power Electronics 11 Chapter 19: Resonant Conversion Construction of H = V / Vg – Resonant (high Q) case C = 0.1 μF, L = 1 mH, Re = 10 Ω Buck characteristic Fundamentals of Power Electronics 12 Chapter 19: Resonant Conversion Construction of Zi Fundamentals of Power Electronics 15 Chapter 19: Resonant Conversion Construction of Zi – Non-resonant (low Q) case C = 0.1 μF, L = 1 mH, Re = 1 kΩ Fundamentals of Power Electronics 16 Chapter 19: Resonant Conversion Construction of H – Non-resonant (low Q) case C = 0.1 μF, L = 1 mH, Re = 1 kΩ Fundamentals of Power Electronics 17 Chapter 19: Resonant Conversion 19.2.3 Parallel resonant dc-dc converter Differs from series resonant converter as follows: Different tank network Rectifier is driven by sinusoidal voltage, and is connected to inductive-input low-pass filter Need a new model for rectifier and filter networks Fundamentals of Power Electronics 20 Chapter 19: Resonant Conversion Effective resistance Re Again define In steady state, the dc output voltage V is equal to the average value of | vR |: For a resistive load, V = IR. The effective resistance Re can then be expressed Fundamentals of Power Electronics 21 Chapter 19: Resonant Conversion Equivalent circuit model of uncontrolled rectifier with inductive filter network Dependent voltage source based on rectified tank voltage. Vs. SRC, dependent current source based on rectified tank current. Fundamentals of Power Electronics 22 Chapter 19: Resonant Conversion Equivalent circuit model Parallel resonant dc-dc converter Fundamentals of Power Electronics 25 Chapter 19: Resonant Conversion Construction of H = V / Vg – Resonant (high Q) case C = 0.1 μF, L = 1 mH, Re = 1 kΩ Buck-boost characteristic Fundamentals of Power Electronics 26 Chapter 19: Resonant Conversion Construction of Zo Fundamentals of Power Electronics 27 Chapter 19: Resonant Conversion Construction of H