Rectifier control system for a DC power plant system

In a power plant system including a plurality of individual rectifiers, input means for coupling AC power to the rectifiers, output means for coupling the rectifiers to a load, apparatus responsive to load current demands for controlling an ON/OFF operational state of the individual rectifiers in order to maximize power efficiency of the power plant system comprising

• means for determining a sum of rated capacities of rectifiers presently operating,
• means for sensing a load current demand,
• means for periodically comparing the load current demand with the sum of rated current capacities of presently operating rectifiers to establish a difference value between the sum of rated current capacities and the load current demand, and
• means for periodically responding to the difference value between the load current demand and the sum of rated current capacities of presently operating rectifiers and operative for changing an operational state of at least one rectifier selected with a rated capacity so as to have a sum of rated current capacities of subsequently operating rectifiers substantially equal to the load current demand.

A method of controlling rectifiers of a power plant system to maximize power efficiency of the power plant system in supplying power to a varying load comprising the steps of

• grouping all the rectifiers into classes of rectifiers of equal current rated capacity
• periodically determining a load current demand presently required by the varying load
• periodically determining a sum of rated current capacities of all rectifiers presently operating
• comparing the load current demand with the sum of rated current capacities and calculating a difference value
• selecting a rectifier from a group of current rated capacity substantially equal to but not greater than the difference value calculated and changing its operational state
• whereby the sum of rated current capacities of rectifiers now operating substantially equals the load current demand required by the load.

A method of controlling a plurality of rectifiers in a power plant system supplying load current to a varying load comprising the steps of

• monitoring an elapsed operating time of each individual rectifier and creating a stored record thereof
• classifying each of the rectifiers into distinct groups of rectifiers, wherein each rectifier of a group has an identical rated current capacity common to that group
• sensing a present load current demand of the varying load
• periodically comparing the present load current demand with total rated current capacity of presently operating rectifiers, and
• responding if the present load current demand exceeds the total rated current capacity of presently operating rectifiers by turning on at least one additional rectifier by a process of
• selecting a presently nonoperative rectifier from a group of rectifiers with a current rated capacity that when summed with the total rated current capacity of presently operating rectifiers exceeds the present load current demand by a minimum amount, and
• examining the stored record of elapsed operating time of rectifiers in the group selected in the preceding step and turning on a presently nonoperative rectifier of that group having a minimum elapsed operating time.

A rectifier power plant including a plurality of rectifiers, input means for coupling AC power to the rectifiers, output means for coupling the rectifiers to a varying load, and control means for controlling an ON/OFF state of the rectifiers in order to maximize power efficiency, and further having the rectifiers grouped into classes of rectifiers of equal current rated capacity

• the control means including
• means for periodically determining a load current demand presently required by the varying load
• means for periodically determining a sum of rated current capacities of all rectifiers presently operating
• means for comparing the load current demand with the sum of rated current capacities and calculating a difference value
• means for selecting a rectifier from a group of rated current capacity substantially equal to but not greater than the difference value calculated and changing its operational state
• whereby the sum of rated current capacities of rectifiers now operating substantially equals the load current demand required by the load.

A power plant system comprising

• a plurality of rectifiers, input means for coupling a primary AC power source to the rectifiers, output means for coupling the rectifiers to a varying load to be energized, each of the rectifiers being classified into distinct groups of rectifiers, wherein each rectifier of a group has an identical rated current capacity common to the group, control means for controlling an ON/OFF state of the rectifiers and operative for maximizing power efficiency of the power plant system, the control means comprising
• means for monitoring an elapsed operating time of each individual rectifier and creating a stored record thereof
• means for sensing a present load current demand of the varying load
• means for periodically comparing the load current demand with total rated current capacity of presently operating rectifiers, and
• means for responding if present load current demands exceeds total rated capacity of presently operating rectifiers by turning on at least one additional rectifier including
• means for selecting a group of rectifiers with a current rated capacity that when summed with total current capacity of presently operating rectifiers exceeds present load current demand by a minimum amount, and
• means for examining the stored record of elapsed operating time of rectifiers in the group selected by the means for selecting and means for turning on a presently nonoperative rectifier of that group having a minimum elapsed operating time.

A power plant system comprising

• input means for accepting a plurality of rectifier circuits, output means for coupling each rectifier circuit to a common load, first current sensing means coupled for monitoring individual current outputs of each rectifier circuit
• second current sensing means coupled for monitoring a current supplied to the common load, control means for controlling an ON/OFF state of the individual rectifiers, the control means including
• data processing means, associated memory means and interface means for coupling the data processing means to the rectifier and the first and second current sensing means
• first instruction means in the memory for periodically determining a load current demand presently required by the common load
• second instruction means in the memory for periodically determining a sum of rated current capacity of all the rectifiers presently operating
• third instruction means in the memory, for comparing the load current demand with the sum of rated current capacity and calculating a difference value
• the memory means having all the rectifiers in register and classified into groups of rectifiers of equal current rated capacity, fourth instruction means in the memory, for selecting a rectifier from a group of rated current capacity substantially equal to but not greater than the difference value calculated and changing its operational ON/OFF state
• whereby the sum of rated current capacities of rectifiers now operating substantially equals the load current demand required by the load.

A power plant system comprising

• input means for accepting a plurality of rectifiers all powered by a primary AC power source
• output means for coupling power supplied by the rectifiers to a varying load to be energized, and control means for controlling an ON/OFF state of the individual rectifiers and operative for maximizing power efficiency of operating rectifiers connected to the power plant system, the control means comprising
• a central data processor means, memory means for storing instructions and operating data and interface means for sensing power plant conditions and translation of instructions into control signals coupled to the individual rectifiers, instruction and operating data of the memory means including
• means for classifying each of the rectifiers into distinct groups of rectifiers, whereas each rectifier of a group has an identical rated current capacity common to the group
• means for monitoring an elapsed operating time of each individual rectifier and creating a stored record thereof
• means for sensing a present load current demand of the varying load
• means for periodically comparing the load current demand with total rated current capacity of presently operating rectifiers, and
• means for responding if present load current demand exceeds total rated current capacity of presently operating rectifiers by turning on at least one additional rectifier including
• means for selecting a group of rectifiers with a current rated capacity that when summed with total current capacity of presently operating rectifiers exceeds present load current demand by a minimum amount, and
• means for examining the stored record of elapsed operating time of rectifiers in the group selected by the means for selecting and means for turning on a presently nonoperative rectifier of that group having a minimum elapsed operating time.