Process and electronic device for the control and regulation of the supply current in an electric motor fed from a fixed voltage direct current source

Claim 1

A process for electronically controlling and regulating the supply current in an electric motor fed from a fixed voltage, direct current source by means of a chopper comprising: generating a measuring voltage, representing the current passing through the motor, and a command voltage representing the command current required to be imposed on the motor; comparing said measuring voltage and said command voltage; applying the results of said comparison to a memory condenser to produce a progressive positive or negative charge voltage in response thereto; generating a reference voltage; comparing said progressive charge voltage with said reference voltage; determining a first time delay period after said progressive charge voltage exceeds said reference voltage; generating a conduction initiation signal for the chopper upon expiration of said first time delay period to initiate application of conduction current to a motor connected to the chopper; reducing the difference between said measuring voltage and said command voltage; determining a second time delay period after said progressive charge voltage falls below said reference voltage; and generating a conduction cutoff signal for said chopper upon expiration of said second time delay period for terminating said conduction current.

Claim 4

A device for electronically controlling and regulating the supply current in an electric motor fed from a fixed voltage, direct current source by means of a chopper, comprising: a shunt coupled to the electric motor for producing a motor current representation signal; potentiometric means for producing a command signal representing the command current required to be imposed on the motor; a differential measuring amplifier for comparing said motor current representation signal and said command signal; a memory condensor for storing a signal representative of the result of the comparison by said differential amplifier; a positive charge circuit, responsive to the differential measuring amplifier output assuming a positive voltage for producing a voltage to selectively positively charge the memory condensor; a negative charge circuit, responsive to the differential measuring amplifier output assuming a negative voltage for producing a voltage to selectively negatively charge the memory condensor; a source of reference voltage; a comparator for comparing the charge level of the memory condensor with said reference voltage; means for determining a first time delay period after the charge level of said memory condensor exceeds said reference voltage; means for generating a conductive initiation signal after said first time delay period; means for adjusting said command signal to reduce the difference between said motor current representaton signal and said command signal; means for determining a second time delay period after said progressive charge voltage falls below said reference voltage; and means for generating a conduction cutoff signal after said second time delay period to terminate said motor current.

Claim 5

A device for electronically controlling and regulating the supply current in an electric motor fed from a fixed voltage, direct current source by means of a chopper, comprising: a shunt coupled to the electric motor for producing a motor current representation signal; potentiometric means for producing a command signal representing the command current required to be imposed on the motor; a differential measuring amplifier for comparing said motor current representation signal and said command signal; a memory condensor for storing a signal representative of the result of the comparison by said differential amplifier; a positive charge circuit, responsive to the differential measuring amplifier output assuming a positive voltage for producing a voltage to selectively positively charge the memory condensor; a negative charge circuit, responsive to the differential measuring amplifier output assuming a negative voltage for producing a voltage to selectively negatively charge the memory condensor; a source of reference voltage; a comparator for comparing the charge level of the memory condensor with said reference voltage; means for determining a first time delay period after the charge level of said memory condensor exceeds said reference voltage; means for generating a conductive initiation signal after said first time delay period; means for adjusting said command signal to reduce the difference between said motor current representaton signal and said command signal; means for determining a second time delay period after said progressive charge voltage falls below said reference voltage; and means for generating a conduction cutoff signal after said second time delay period to terminate said motor current.