Plural motor electronic phasing system

Claim 1

A phase correction system for aligning at least first and second synchronously rotating devices to a predetermined angular relationship comprising: angle indicating means coupled to each rotating device for generating electrical backstroke signals indicative of the angular position of a rotating device, error generating means coupled to said angle indicating means for producing an electrical error signal in response to said backstroke signals representative of the angular displacement between said rotating devices, said error generating means including means for establishing sample periods during each of which said error signal is generated, wherein the duration of said sample period is substantially equal to the duration of the period of said backstroke signal indicating the angular position of said first rotating device, and wherein said error signal is a variable duration pulse having a duration substantially equal to the time period between common points within the cycles of said backstroke signals, correction generating means coupled to said error generating means for producing an electrical correction signal in response to said error signal capable of effecting a partial alignment of said rotating devices to said predetermined angular relationship, and speed control means coupled to said correction generating means and said first rotating device to vary the angular velocity of said rotating device in response to said correction signal causing said rotating devices to approach said predetermined angular relationship, wherein said speed control means varies the angular velocity of said first rotating device by a fixed number of revolutions per unit time, said correction generating means including a multiplying circuit coupled to receive said error signals for producing a correction signal each time an error signal is generated, the duration of said correction signal, at least when less than or equal to the duration of said sample period, being a variable duration substantially a constant multiple of the duration of said error signal, the duration of said error signal causing said speed control means to vary the velocity of said first rotating device for a length of time sufficient to reduce the error indicated by said error signal by a fractional amount.

Claim 3

A system for aligning at least first and second rotating devices substantially to a predetermined angular relationship comprising, angle indicating means coupled to each rotatinG device for generating backstroke signals indicative of the angular position and velocity of said rotating devices, the periods of said backstroke signals associated with said first and second rotating devices being Pr and Pt respectively, error generating means coupled to said angle indicating means for producing an error signal, Te, representative of the angular displacement between said rotating devices from said predetermined angular relationship, said error signal being generated during periods, Pr, of said backstroke signal associated with said first rotating device, correction generating means coupled to said error generating means for generating a correction signal, Tc, related to said error signal according substantially to the expression Tc Pr/B Delta p Te, where B is equal to or greater than one and Delta p is equal to Pr- Pt, said correction generating means including means coupled to receive said error signal for producing a first signal for the duration of said error signal, said first signal increasing in voltage amplitude, relative to a reference voltage during its generation, means for producing a second signal following the generation of said first signal, said second signal having an initial voltage amplitude substantially equal to the final amplitude of said first signal and decreasing in amplitude until its amplitude is substantially equal to said reference voltage or until the end of said period Pr and a pulse generator coupled to receive said first and second signals for producing said correction signal while the voltage amplitudes of said signals are equal to or greater than said reference voltage, said correction signal, at least when its duration is equal to or less than that of said period Pr being related to said error signal according substantially to said expression Tc Pr/B Delta p Te, and speed control means coupled to said correction generating means and said first rotating device for varying in response to said correction signal the angular velocity of said first rotating device by a fixed number of revolutions per unit time causing said rotating devices to approach said predetermined angular relationship.

Claim 4

A system for aligning at least first and second rotating devices substantially to a predetermined angular relationship comprising, angle indicating means coupled to each rotatinG device for generating backstroke signals indicative of the angular position and velocity of said rotating devices, the periods of said backstroke signals associated with said first and second rotating devices being Pr and Pt respectively, error generating means coupled to said angle indicating means for producing an error signal, Te, representative of the angular displacement between said rotating devices from said predetermined angular relationship, said error signal being generated during periods, Pr, of said backstroke signal associated with said first rotating device, correction generating means coupled to said error generating means for generating a correction signal, Tc, related to said error signal according substantially to the expression Tc Pr/B Delta p Te, where B is equal to or greater than one and Delta p is equal to Pr- Pt, said correction generating means including means coupled to receive said error signal for producing a first signal for the duration of said error signal, said first signal increasing in voltage amplitude, relative to a reference voltage during its generation, means for producing a second signal following the generation of said first signal, said second signal having an initial voltage amplitude substantially equal to the final amplitude of said first signal and decreasing in amplitude until its amplitude is substantially equal to said reference voltage or until the end of said period Pr and a pulse generator coupled to receive said first and second signals for producing said correction signal while the voltage amplitudes of said signals are equal to or greater than said reference voltage, said correction signal, at least when its duration is equal to or less than that of said period Pr being related to said error signal according substantially to said expression Tc Pr/B Delta p Te, and speed control means coupled to said correction generating means and said first rotating device for varying in response to said correction signal the angular velocity of said first rotating device by a fixed number of revolutions per unit time causing said rotating devices to approach said predetermined angular relationship.