Microprocessor-based control apparatus for a direct current machine drive system

Claim 1

A method of controlling a DC machine drive supplied with power from an external source during steady state operation using a microcomputer having stored machine constants, the machine drive having an armature current control loop and an air gap flux control loop, said method comprising the steps of: (1) measuring armature and field voltages and currents, and machine speed; (2) determining air gap flux from measured field current and one of said stored machine constants; (3) determining machine torque from air gap flux, armature current and another of said stored machine constants; (4) determining machine ohmic losses from measured field voltage, field current and armature current and selected ones of said machine constants; (5) determining machine efficiency from machine losses and power input to the machine; (6) processing machine efficiency as a function of air gap flux to determine whether air gap flux should be increased or decreased to increase machine efficiency; (7) varying air gap flux by a predetermined amount in accordance with the output of said air gap flux control loop; (8) varying armature current in accordance with the output of said armature current control loop so that the previously determined torque is maintained; (9) commanding the new values of armature current and air gap flux in said armature current control loop and air gap flux control loop, respectively; and (10) repeating steps 1-10.

Claim 2

A method of controlling a DC machine drive supplied with power from an external source during steady state operation using a microcomputer having stored machine constants, the machine drive having an armature current control loop and an air gap flux control loop, said method comprising the steps of: (1) measuring armature and field voltages and currents, and machine speed; (2) determining air gap flux from measured field current and one of said stored machine constants; (3) determining machine torque from air gap flux, armature current and another of said stored machine constants; (4) determining machine ohmic losses from measured field voltage, field current and armature current and selected ones of said machine constants; (5) determining machine efficiency from machine losses and power input to the machine; (6) processing machine efficiency as a function of air gap flux to determine whether air gap flux should be increased or decreased to increase machine efficiency; (7) varying air gap flux by a predetermined amount in accordance with the output of said air gap flux control loop; (8) varying armature current in accordance with the output of said armature current control loop so that the previously determined torque is maintained; (9) commanding the new values of armature current and air gap flux in said armature current control loop and air gap flux control loop, respectively; and (10) repeating steps 1-10.

Claim 4

A method of controlling a DC machine drive supplied with power from an external source during steady state operation, using a microcomputer having stored machine constants, the machine drive having an armature current control loop and an air gap flux control loop, said method comprising the steps of; (1) measuring armature and field voltages and currents, and machine speed; (2) determining air gap flux from measured field current and one of said stored machine constants; (3) determining machine torque from air gap flux, armature current and another of said stored machine constants; (4) determining machine ohmic losses from measured field voltage, field current and armature current and selected ones of said machine constants; (5) determining machine efficiency from machine losses and power input to the machine; (6) processing machine efficiency as a function of armature current to determine whether armature current should be increased or decreased to increase machine efficiency; (7) varying armature current by a predetermined amount in accordance with the output of said armature current control loop; (8) varying air gap flux in accordance with the output of said air gap flux control loop so that the previously determined torque is maintained; (9) commanding the new value of armature and air gap flux in said armature current control loop and air gap flux control loop, respectively; (10) repeating steps 1-10.

Claim 5

A method of controlling a DC machine drive supplied with power from an external source during steady state operation, using a microcomputer having stored machine constants, the machine drive having an armature current control loop and an air gap flux control loop, said method comprising the steps of; (1) measuring armature and field voltages and currents, and machine speed; (2) determining air gap flux from measured field current and one of said stored machine constants; (3) determining machine torque from air gap flux, armature current and another of said stored machine constants; (4) determining machine ohmic losses from measured field voltage, field current and armature current and selected ones of said machine constants; (5) determining machine efficiency from machine losses and power input to the machine; (6) processing machine efficiency as a function of armature current to determine whether armature current should be increased or decreased to increase machine efficiency; (7) varying armature current by a predetermined amount in accordance with the output of said armature current control loop; (8) varying air gap flux in accordance with the output of said air gap flux control loop so that the previously determined torque is maintained; (9) commanding the new value of armature and air gap flux in said armature current control loop and air gap flux control loop, respectively; (10) repeating steps 1-10.