Granted Patent B2

US 7,061,134 · App. 10/632,257 · Granted Jun 13, 2006

Abstract

Claims (20)

1. A method of thermal management in a voltage source inverter, the method comprising:

sensing a low output frequency condition corresponding to zero or low voltage across phases in the voltage source inverter while the voltage source inverter is receiving a constant DC link voltage;

determining a zero vector modulation to the sensed low output frequency condition; and

applying the determined zero vector modulation to reduce thermal stress in the voltage source inverter.

2. The method of claim 1 , wherein determining the zero vector modulation responsive to the sensed low output frequency condition comprises:

mapping an output voltage requirement to a space vector structure; and

determining state switching space vectors based on the mapped output voltage requirement.

3. The method of claim 2 , wherein the magnitude of a combination of state switching space vectors is equal to the magnitude of the output voltage requirement.

4. The method of claim 2 , wherein determining the state switching space vectors comprise:

determining active state switching space vectors associated with the state switching space vectors;

determining duty cycles for the active state switching space vectors based on the active state switching space vectors and the mapped output voltage requirement; and

determining a duty cycle for at least one zero state switching space vector based on the determined duty cycles of the active state switching space vectors and a switching period.

5. The method of claim 4 , wherein the duty cycle for the at least one zero state switching space vectors is selected from the group consisting of: a first zero state duty cycle, a second zero state duty cycle, and a combination of the zero state duty cycles.

6. The method of claim 1 , wherein applying the determined zero vector modulation to reduce thermal stress in the voltage source inverter comprises:

applying a net voltage from the inverter to a load when active state switching space vectors are utilized; and

applying a shorted voltage from the inverter to the load when zero state switching space vectors are utilized.

7. A system for thermal management in a voltage source inverter, the system comprising:

means for sensing a low output frequency condition corresponding to zero or low voltage across phases in the voltage source inverter while the voltage source inverter is receiving a constant DC link voltage;

means for determining a zero vector modulation responsive to the sensed low output frequency condition; and

means for applying the determined zero vector modulation to reduce thermal stress in the voltage source inverter.

Assignments (13)