Load sharing techniques for electric power sources
AssigneeCaterpillar Inc.
InventorsPhilip L. Limoge, Matthew L. Andrews, Edward M. Schroeder
Life of this patent
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Abstract
Techniques are described that not only weigh frequency/voltage and real/reactive load sharing separately, but also utilize a window around a setpoint, such as a percentage of an output range, and determine whether there is oscillation. In response, a control system can adjust a time-independent component of a closed-loop controller to weaken the time-independent component to try and reduce the oscillation. The control system can continue to monitor and weaken the time-independent component until it reaches some limit or until it comes back into control.
Claims18
A control system to monitor and control a first electric power source coupled in parallel with a second electric power source, wherein the first electric power source and the second electric power source are configured to share a load, the control system comprising:
- a processor configured to:
- receive a representation of a first measurement and a representation of a second measurement, wherein the first measurement and the second measurement are measurements of different characteristics of the first electric power source;
- apply a first filter to the representation of the first measurement and a second filter to the representation of the second measurement, wherein at least one of the first filter and the second filter includes an exponential weighted moving average filter;
- generate corresponding error values for the filtered first measurement and the filtered second measurement and combine the corresponding error values as a single first error value;
- compare the single first error value to a first window, wherein the first window defines upper and lower limits about a first characteristic of the first electric power source around a setpoint, and wherein the first window is configured to generate a first output signal representing an adjustment to a time-independent component of a closed-loop controller;
- and
- generate, using the first output signal and the closed-loop controller having a time-dependent component and the time-independent component, a first control signal;
- and
- a controller coupled to the first electric power source and configured to receive the first control signal and, in response, adjust the first characteristic of the first electric power source.
A computer-implemented method of monitoring and controlling a first electric power source coupled in parallel with a second electric power source, wherein the first electric power source and the second electric power source are configured to share a load, the computer-implemented method comprising:
- receiving a representation of a first measurement and a representation of a second measurement, wherein the first measurement and the second measurement are measurements of different characteristics of the first electric power source;
- applying a first filter to the representation of the first measurement and a second filter to the representation of the second measurement, wherein at least one of the first filter and the second filter includes an exponential weighted moving average filter;
- generating corresponding error values for the filtered first measurement and the filtered second measurement and combining the corresponding error values as a single first error value;
- comparing the single first error value to a first window, wherein the first window defines upper and lower limits about a first characteristic of the first electric power source around a setpoint;
- generating a first output signal representing an adjustment to a time-independent component of a closed-loop controller;
- generating, using the first output signal and the closed-loop controller having a time-dependent component and the time-independent component, a first control signal;
- and
- adjusting, based on the first control signal, the first characteristic of the first electric power source.
A control system to monitor and control a first electric power source coupled in parallel with a second electric power source, wherein the first electric power source and the second electric power source are configured to share a load, the control system comprising:
- a processor configured to:
- receive a representation of a first measurement and a representation of a second measurement, wherein the first measurement and the second measurement are measurements of different characteristics of the first electric power source;
- apply a first filter to the representation of the first measurement and a second filter to the representation of the second measurement, wherein at least one of the first filter and the second filter includes an exponential weighted moving average filter;
- generate corresponding error values for the filtered first measurement and the filtered second measurement and combine the corresponding error values as a single first error value;
- compare the single first error value to a proportional component window, wherein the proportional component window defines upper and lower limits about a first characteristic of the first electric power source around a setpoint, and wherein the proportional component window is configured to generate a first output signal representing an adjustment to a proportional component of a closed-loop controller;
- and
- generate, using the first output signal and a controller having the proportional component and an integral component, a first control signal;
- and
- a controller coupled to the first electric power source and configured to receive the first control signal and, in response, adjust the first characteristic of the first electric power source.
Dependencies are inferred from the claim text.