Cascaded variable bias feedforward and feedback flow and level control system
OwnerGuy Kevin Spicerinventor
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Abstract
A control system for maintaining the liquid levels in a plurality of reservoirs connected in series includes one or more nested control modules. The nested control module, one for each reservoir, includes a proportional only level controller in electrical communication with the respective level sensor of each respective reservoir and is adapted to produce an output that becomes a set point for one or more respective PID flow controllers adapted to control the respective outflows of said respective reservoirs. The control system results in maintaining liquid levels in the reservoirs while substantially eliminating flow and level oscillations.
Claims8
In a liquid flow system comprising a plurality of reservoirs connected in series by pipelines or open channels including at least one first reservoir (V1) and a level sensor, at least one inflow (F0) and at least one outflow (F1), each said inflow and outflow including flow measuring devices and said outflow including a flow manipulation device, the improvement comprising a cascaded variable bias feedforward and feedback flow and level control system for maintaining liquid levels in said reservoirs while substantially eliminating flow and level oscillations, said control system comprising the following:
- (a) a nested control module comprising:
- (i) a proportional only level controller for maintaining a desired liquid level in the at least one first reservoir (V1), said proportional only level controller in electrical communication with the level sensor of said at least one first reservoir (V1), and
- (ii) a PID flow controller adapted to control the flow manipulation device of the at least one first reservoir outflow (F1),
- wherein said nested control module proportional only level controller is adapted to respond to the level sensor of said at least one first reservoir (V1) and a calculated bias value resulting from the total inflow (F0) to said at least one first reservoir (V1) to produce an output signal that is cascaded to the nested control module PID flow controller to become a set point thereof.
Dependencies are inferred from the claim text.