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ECE631/EE631Q Lecture 16: Average Value Model. S.D.Sudhoff Purdue University. IM Overview. Objectives For Today. Develop an Average Value Model for the 3-Phase Bridge Inverter Features Include conduction losses Ignore switching losses. Semiconductor Model. Transistor Diode.
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ECE631/EE631QLecture 16: Average Value Model S.D.Sudhoff Purdue University EE631 – Spring 2005
IM Overview EE631 – Spring 2005
Objectives For Today • Develop an Average Value Model for the 3-Phase Bridge Inverter • Features • Include conduction losses • Ignore switching losses EE631 – Spring 2005
Semiconductor Model • Transistor • Diode EE631 – Spring 2005
AVM – DC Currrent • Consider the current reference frame EE631 – Spring 2005
AVM – DC Current • Sine-Triangle Modulation with 3rd Harmonic EE631 – Spring 2005
AVM – DC Current • We have EE631 – Spring 2005
AVM – DC Current • We have EE631 – Spring 2005
AVM – DC Current EE631 – Spring 2005
AVM – DC Current • Thus we have for the a-phase • The total dc current must be given by EE631 – Spring 2005
AVM - Voltage • The fast average voltages may be expressed EE631 – Spring 2005
AVM - Voltage • The fundamental component of the line-to-ground voltage may be expressed EE631 – Spring 2005
AVM - Voltage • After substantial manipulation EE631 – Spring 2005
AVM - Voltage • After a little more work, we have • To show this EE631 – Spring 2005
AVM - Voltage EE631 – Spring 2005
AVM – Modulation Signal • Problem: we need to know d, d3, f • Starting point: modulation indices EE631 – Spring 2005
AVM – Modulation Signal • We will need the modulation signal in the current reference frame EE631 – Spring 2005
AVM – Modulation Signal • It can be shown that • To show this EE631 – Spring 2005
AVM – Modulation Signal EE631 – Spring 2005
AVM – Modulation Signal EE631 – Spring 2005
AVM – Modulation Signal • Lets also define a voltage reference frame • In this frame EE631 – Spring 2005
AVM – Modulation Signal • To show this EE631 – Spring 2005
AVM – Modulation Signal • Since we have • We therefore have EE631 – Spring 2005
AVM Modulation Signal • Desired magnitudes • For unsaturated operation EE631 – Spring 2005
AVM - Modulation • Analysis plan for saturated operation EE631 – Spring 2005
AVM Modulation • Results EE631 – Spring 2005
AVM Modulation • A subtle point • This occurs when EE631 – Spring 2005
AVM – Hysteresis Modulator EE631 – Spring 2005