GE DMC490 Software Configuration Manual page 14

DMC490 Microgrid Controller Software Configuration Guide
Figure 10 Data flow for a system with dispatchables, renewables, and storage
Loads
Power consumed
Online status
Power generated
Renewable
Online status
generators
Availability
Power generated
Power generated
Power consumed
Online status
State of charge
Availability
Online status
Availability
Model Predictive Control
Model predictive control (MPC) is used for optimal dispatch in the microgrid. In this method, a model of the
process to be controlled is used to evaluate the behavior of process outputs in response to control inputs. The
model response is evaluated for a finite period extending into the future, known as a prediction horizon. The
outputs are optimized over this period in order to arrive at the ideal values of outputs to be applied at the
current time.
Figure 11 Model predictive control
Applied to the dispatch challenge, inputs represent internal physical states of the process such as
offline/online, availability, isochronous operation, storage state of charge, and metered power of the devices.
Generators and storage devices are modeled by their power ratings and efficiency curves. Forecasts model the
loading of the power system, the contribution of renewable sources, and the price of grid power (if one exists).
Finally, outputs take the form of start/stop commands and power reference commands applied to generators
and storage devices.
Generation must match load in a stable power system. Dispatchable generation including the storage equals
the total load minus the total power supplied by renewable sources. These resources are assumed to have
local controllers that are designed to maximize the use of available renewable energy.
The problem to be solved by the MGC is a multi-interval optimization problem. As shown in Figure 12, an
assumed prediction horizon of 24 hours is divided into multiple time steps/intervals, such as 120 twelve-minute
or 240 six-minute time intervals.
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Setup tool
Operational
parameters (settings)
DMC490
Microgrid Controller
System
Isochronous/droop
Output preferences
Dispatchable
generators
Storage
devices
Start/stop
Start/stop
Input preferences
Output preferences