System for economic unit load distribution during process load transition

In a plant including a multiplicity of energy conversion units, each having an energy input and all coupled to a common junction for supplying load upon demand to a process;

• first control means for generating a first signal to govern said energy conversion units to collectively supply load to the process in accordance with the process load demand;
• and second control means, corresponding to each energy conversion unit, governed by a corresponding second signal to control the energy input of its corresponding energy conversion unit to achieve a desired unit load supply therefrom which contributes to the process load demand, a system for allocating load dynamically and economically among the multiplicity of energy conversion units to meet the process load demand during a transition from one steady-state loading condition to another, said system comprising:
• load allocating means including:
• means for calculating a cost of operating each energy conversion unit across its corresponding load supply spectrum based on corresponding efficiency characteristics of each unit determined from data measurements collected over the load supply spectrum of its corresponding unit;
• means for determining an instantaneous process load demand;
• means for deriving a set of unit load supply signals corresponding to each energy conversion unit to meet said instantaneous process load demand and virtual perturbations therefrom based on an optimal economic unit load supply distribution algorithm using said cost of operating calculations for said instantaneous and virtually perturbed values of process load demand;
• first means for generating at least one gain control signal for each energy conversion unit based on a function of said corresponding set of unit load supply signals;
• second means for generating a bias signal for each energy conversion unit based on a function of at least one signal from said corresponding set of unit load supply signals;
• and
• third means for generating a demand signal for each energy conversion unit based on a function of said first signal;
• and
• load control means for each energy conversion unit, each load control means governed by said first signal to generate said second signal which controls the corresponding energy conversion unit to render a desired unit load supply to meet the change in process load demand during said transition, each load control means including:
• fourth means for generating a third signal based on a function of said first signal and corresponding demand signal;
• means governed by said corresponding at least one gain signal to gain adjust said third signal and render a fourth signal representative of said gain adjusted third signal;
• and
• fifth means for generating said corresponding second signal based on a function of said fourth and bias signals.