VSCF system with DC link harmonics control
AssigneeSundstrand Corporation
InventorsGregory I. Rozman, Vijay K. Maddali
Life of this patent
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Abstract
The problem of reducing harmonic content of AC bus voltage in a power system (10) is minimized using a controller (30) for a PWM inverter (38). The controller (30) develops a duty cycle command on a line (40) for controlling operation of the PWM inverter (38). The controller (30) develops the duty cycle command to maintain the PWM inverter output voltage at a desired level. This duty cycle command is modulated in accordance with the harmonic content evident on a DC bus (34) which supplies power to the PWM inverter (38).
Claims18
In a control system for an inverter powered by a DC source, the inverter being controlled to provide a select duty cycle to control inverter output voltage, the improvement comprising:
- means for developing a duty cycle command representing a duty cycle necessary to maintain inverter output voltage at a desired level;
- means for sensing harmonic content from said DC source;
- and
- means coupled with said developing means and said sensing means for modulating said duty cycle command responsive to the harmonic content from the DC source to provide an inverter output voltage having reduced harmonic content.
In a control system for an inverter powered by a DC source, the inverter being controlled to provide a select duty cycle to control inverter output voltage, the improvement comprising:
- means for developing a duty cycle command representing a select duty cycle for inverter operation;
- means for sensing harmonic content from said DC source, said sensing means including means for sensing voltage from the DC source and means for separating the DC content and harmonic content of the voltage from said DC source;
- and
- means coupled with said developing means and said sensing means for modulating said duty cycle command to provide an inverter output voltage having reduced harmonic content.
In a control system for an inverter coupled to a DC bus, the inverter being controlled in accordance with a duty cycle command to provide a select inverter output voltage, the improvement comprising:
- means for selecting an inverter output reference representing a desired inverter output voltage;
- means for sensing actual inverter output voltage;
- means coupled to said selecting means and said sensing means for determining a duty cycle reference responsive to said desired and said actual inverter output voltage;
- and
- means operatively associated with said determining means for modulating said duty cycle reference to produce said duty cycle command to provide an inverter output voltage having reduced harmonic content.
In a control system for an inverter coupled to a DC bus, the inverter being controlled in accordance with a duty cycle command to provide a select inverter output voltage, the improvement comprising:
- means for selecting an inverter output reference representing a desired inverter output voltage;
- means for sensing actual inverter output voltage;
- means coupled to said selecting means and said sensing means for determining a duty cycle reference responsive to said desired and said actual inverter output voltage;
- and
- means operatively associated with said determining means for modifying said duty cycle reference to produce said duty cycle command to provide an inverter output voltage having reduced harmonic content, said modifying means including means for sensing DC bus voltage and means for separating the DC content and harmonic content of the DC bus voltage.
A control system for an inverter coupled to a power source which provides a DC bus voltage, said DC bus voltage including undesirable harmonics, comprising:
- means for selecting an inverter output reference representing a desired inverter output voltage;
- first sensing means for sensing actual inverter output voltage;
- means coupled to said selecting means and said sensing means for determining a duty cycle reference responsive to said desired and said actual inverter output voltage;
- second sensing means for sensing harmonic content in said DC bus voltage;
- and
- means coupled with said determining means and said second sensing means for modulating said duty cycle reference to produce said duty cycle command to provide an inverter output voltage having reduced harmonic content.
A control system for an inverter coupled to a power source which provides a DC bus voltage, said DC bus voltage including undesirable harmonics, comprising:
- means for selecting an inverter output reference representing a desired inverter output voltage;
- first sensing means for sensing actual inverter output voltage;
- means coupled to said selecting means and said sensing means for determining a duty cycle reference responsive to said desired and said actual inverter output voltage;
- second sensing means for sensing harmonic content in said DC bus voltage, said second sensing means including means for sensing DC bus voltage and means for separating the DC content and harmonic content of said DC bus voltage;
- and
- means coupled with said determining means and said second sensing means for modifying said duty cycle reference to produce said duty cycle command to provide an inverter output voltage having reduced harmonic content.
Dependencies are inferred from the claim text.