Electric power system with line drop compensation

• US 5,117,174 A
• Filed: 10/03/1989
• Issued: 05/26/1992
• Est. Priority Date: 10/03/1989
• Status: Expired due to Fees

• Current Assignee: Sundstrand Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: Westinghouse Electric Company LLC (Brookfield Asset Management Incorporated)
• Inventors: Kessler, Leland L.
• Primary Examiner(s): Stephan, Steven L.
• Assistant Examiner(s): KINCAID, KRISTINE LYNN
• Application Number:
  US07/416,565
• Time in Patent Office: 966 Days
• Field of Search: 322/21, 322/23, 322/24, 322/25, 322/28, 322/59, 322/73, 322/99
• US Class Current: 322/21
• CPC Class Codes: H02P 2101/30 for aircraft
• CPC Class Codes: H02P 9/30 using semiconductor devices

Abstract

An electric power system having line drop compensation includes a controllable electric power source having an output for supplying voltage to a power bus, a local voltage regulator for monitoring the output voltage of the power source and for producing a control signal representative of a desired nominal output voltage of the power source, and a remote voltage regulator for sensing voltage on the power bus at a point of regulation located away from the power source. The remote voltage regulator produces a pulse width modulated signal having a duty cycle representative of the voltage at the point of regulation. A pulse width to trim bias converter receives the pulse width modulated signal and produces the trim signal having a magnitude representative of the duty cycle of the pulse width modulated signal. This trim signal is combined with the control signal of the local voltage regulator to produce a modified control signal for controlling the output voltage of the power source to produce a predetermined voltage at the point of regulation.

Claims

1. An electric power system having line drop compensation, said system comprising:

a controllable electric power source having an output for supplying voltage to a power bus;

a local voltage regulator for monitoring the output voltage of said power source and for producing a control signal representative of a desired nominal output voltage of said power source;

a remote voltage regulator for sensing voltage on said power bus at a point of regulation located away from said power source, and for producing a pulse width modulated signal having a duty cycle representative of the voltage at said point of regulation;

a pulse width to trim bias converter for receiving said pulse width modulated signal and for producing a trim signal having a magnitude representative of the duty cycle of said pulse width modulated signal; and

means for combining said control signal with said trim signal to produce a modified control signal for controlling the output voltage of said power source to produce a predetermined voltage at said point of regulation.

2. An electric power system as recited in claim 1, wherein:

the response time of said trim bias converter is greater than the response time of said local voltage regulator.

3. An electric power system as recited in claim 1, wherein:

said trim signal is independent of the magnitude of said pulse width modulated signal.

4. An electric power system as recited in claim 1, wherein:

the duty cycle of said pulse width modulated signal is about 30% when said power bus is not loaded.

5. An electric power system as recited in claim 1, wherein said pulse width to trim bias converter comprises:

a differential amplifier for receiving said pulse width modulated signal, and for producing an amplified pulse width modulated signal;

means for comparing said amplified pulsed width signal with a reference signal;

means for charging a capacitor when said amplified pulse width signal exceeds said reference signal; and

means for producing said trim bias signal in response to the voltage on said capacitor.

6. A method of line drop compensation in an electric power system, said method comprising the steps of:

providing a controllable electric power source;

connecting said controllable power source to a power bus;

producing a control signal representative of a desired nominal output voltage of said power source;

sensing voltage on said power bus at a point of regulation located away from said power source;

producing a pulse width modulated signal having a duty cycle representative of the voltage at said point of regulation;

producing a trim signal having a magnitude representative of the duty cycle of said pulse width modulated signal; and

combining said control signal with said trim signal to produce a modified control signal for controlling the output voltage of said power source to produce a predetermined voltage at said point of regulation.

7. A method of line drop compensation, as recited in claim 6, wherein:

said trim signal is independent of the magnitude of said pulse width modulated signal.

8. A method of line drop compensation, as recited in claim 6, wherein:

the duty cycle of said pulse width modulated signal is about 30% when said power bus is not loaded.