Load peak shaver power regulating system

Claim 2

A power regulating system for a cyclically varying load comprising: a. main power supply means connected to said load, said main power supply means being capable of supplying average power to said cyclically varying load and having a predetermined range about the average power within which range power excursions of short durations may permissibly occur; b. means for measuring instantaneous power flow to said load; c. means for measuring power to said load over a predetermined interval to obtain average power flow to said load; d. means for comparing instantaneous power flow to said load with average load power to produce a difference signal representative of instantaneous power excursions from the average load; e. auxiliary power supply means connected to said main power supply means; and, f. means responsive to said difference signal for regulating said auxiliary power supply means to continuously generate or absorb power in a predetermined percentage of the excursions of instantaneous power from average power.

Claim 3

A power regulating system for a cyclically varying load according to claim 1 further including means for continuously measuring power generated or absorbed by said auxiliary power supply means, means for comparing the measured auxiliary power supply power with said difference signal representative of instantaneous power excursions from average, and means for altering the output from said auxiliary power supply means by an amount proportional to the variation between said difference signal and a signal proportional to said measured power of said auxiliary power supply means.

Claim 4

A power regulating system for a cyclically varying load according to claim 2 wherein said auxiliary power supply means is a dynamoelectric machine capable of absorbing and generating power by transformation of energy between the electrical and kinetic states and further including speed measuring means for determining the rotary speed of said dynamoelectric machine, means for comparing the measured speed of said dynamoelectric machine with the maximum operating speed of said machine and means responsive to the measured speed for slowly raising said machine to the maximum operating speed of the machine when power command signals are not present.

Claim 5

A power regulating system for a cyclically varying load produced during the digging cycle of excavator equipment comprising main power supply means having a capacity sufficient to supply average load of said excavator equipment while being incapable of sustaining cyclical variations exceeding a predetermined range about said average load, means for detecting the average load of said excavator equipment over a period of time less than the normal digging cycle of said excavator equipment, means for continuously measuring the instantaneous load of said excavator equipment and for continuously comparing said instantaneous load with the average load of said excavator equipment to provide a measured difference therebetween, auxiliary power supply means connected to said cyclically varying load, said auxiliary power supply means being capable of a mutual transformation of energy from the kinetic to the electrical state and being characterized by a rotary mass for storage of kinetic energy, means for measuring power flow between said auxiliary power supply and said cyclically varying load, means responsive to power flow between said cyclically varying load and said auxiliary power supply means and to the measured difference between instantaneous load and average load of said excavator equipment for continuously regulating the power flow of said auxiliary power supply means to generate or absorb power from said auxiliary power supply means in a predetermined percentage of the instantaneous excursions of the cyclically varying load from average load.

Claim 6

A power regulating system for a cyclically varying load produced during the digging cycle of excavator equipment comprising main power supply means having a capacity sufficient to supply average load of said excavator equipment while being incapable of sustaining cyclical variations exceeding a predetermined range about said average load, means for detecting the average load of said excavator equipment over a period of time less than the normal digging cycle of said excavator equipment, means for continuously measuring the instantaneous load of said excavator equipment and for continuously comparing said instantaneous load with the average load of said excavator equipment to provide a measured difference therebetween, auxiliary power supply means connected to said cyclically varying load, said auxiliary power supply means being capable of a mutual transformation of energy from the kinetic to the electrical state and being characterized by a rotary mass for storage of kinetic energy, means for measuring power flow between said auxiliary power supply and said cyclically varying load, means responsive to power flow between said cyclically varying load and said auxiliary power supply means and to the measured difference between instantaneous load and average load of said excavator equipment for continuously regulating the power flow of said auxiliary power supply means to generate or absorb power from said auxiliary power supply means in a predetermined percentage of the instantaneous excursions of the cyclically varying load from average load.

Claim 7

A power regulating system according to claim 4 further including means for measuring power losses within said auxiliary power supply and means for summing said power losses with measured power flow between said auxiliary power supply and said cyclically varying load to obtain a total power flow signal for comparison with the signal representative of instantaneous excursions from average load.

Claim 8

A power regulating system according to claim 4 wherein said auxiliary power supply means is a wound rotor converter having a flywheel mounted thereon and further including means for measuring the speed of said wound rotor converter, means for comparing said measured speed with a signal proportional to the maximum design speed of said wound rotor converter, and means responsive to said comparison means tending to drive said wound rotor converter slowly to said maximum design speed when power flow command signals are not present.

Claim 9

A power regulating system according to claim 6 wherein said means for continuously regulating the load flow of said auxiliary power supply means is a cycloconverter triggered by an adjustable control circuit, the input to said control circuit comprising a first signal proportional to the difference between instantaneous load and average load, a second signal proportional to the power factor of the power flowing between said auxiliary power supply means and said load, a third signal proportional to the difference between rated maximum converter speed and its instantaneous actual speed, and a fourth signal proportional to the slip frequency between the rotor frequency of said wound rotor converter and the frequency of the signal generated by the stator of said wound rotor converter, said control circuit producing an output triggering signal for said cycloconverter proportional to the magnitudes of said first, second and third signals at a frequency equal to the slip frequency of said wound rotor converter.