Motor speed control system with timed speed reference clamp and speed error spill-through circuit

Claim 2

In a D.C. motor control system, the combination with means for adjustably supplying energy to a motor armature, of control means for supplying the first mentioned means with a control voltage which is variable as a function of a speed reference voltage, a speed error feed back voltage and a current error feed back voltage, and comprising: a. speed reference means including means for presetting a desired magnitude of speed reference voltage and means holding change of such voltage to a predetermined timed rate following changes in adjustment of said presettinG means, b. current limit clamp means responsive to an input signal, which is a function of said speed error feed back and said speed reference voltages, rising to or exceeding a preset value to clamp said control voltage to a value holding the motor armature current to a corresponding limited value, and c. timed reference rate of change clamp means in circuit with said current limit clamp means and with said means holding change of said speed reference voltage to predetermined timed rate following adjustment of said presetting means, and responsive to said control voltage being clamped to said value holding the armature current to a corresponding limited value to subject the last mentioned means to a voltage which causes the rate of change in the speed reference voltage to be clamped to a rate corresponding to the actual rate of change in motor speed if the latter voltage has not attained its preset magnitude.

Claim 3

The combination according to claim 1 wherein said timed reference rate clamp means includes a zener diode which is in circuit with the input of said means holding change of speed reference voltage to a predetermined timed rate and is subjected to the same resultant input voltage to which said current limit clamp means is subjected, and further including means causing said input voltage to exceed the breakdown voltage of said zener diode whenever said current limit clamp means clamps said control voltage as aforestated.

Claim 4

The combination according to claim 2 wherein said control means includes speed error detector means responsive to said speed error feed back voltage and said speed reference voltage and spill-through circuit means which is responsive to rise of the output voltage of said speed error detector means above a predetermined value to provide a step increase in the control system gain to thereby increase the damping action on the motor drive.

Claim 5

In a D.C. motor control system, the combination with means for adjustably supplying energy to a motor armature, of control means for supplying the first mentioned means with a control voltage which is variable as a function of a speed reference voltage, a speed error feed back voltage and a voltage which varies with armature current, and comprising a. speed reference meeans including means for presetting a desired magnitude of speed reference voltage and means holding change of such voltage to a predetermined rate following changes in adjustment of said presetting means, b. speed error detector and integrator means providing an output voltage varying in accordance with the output voltage of said speed reference means and said speed error feed back voltage, c. current reference error detector means responsive to the last mentioned output voltage to provide an output voltage varying in accordance therewith, d. current integrator means in circuit with the first mentioned means and normally responsive to the resulted between the output voltage of said current reference error detector means and said voltage which varies with motor armature current to control the output of said first mentioned means in accordance therewith, e. current limit clamp means in circuit between the input to said current integrator means and the output of said current reference error detector means and being responsive to the output voltage of the latter means rising to or exceeding a preset value to clamp the input voltage from the latter means to said current integrator means to a value holding the motor armature current to a corresponding limited value, and f. timed reference rate clamp means in circuit with said current reference error detector means, said current limit clamp means, and said means holding change of said speed reference to a predetermined timed rate and responsive to said current limit clamp means clamping said input voltage to said current integrator means to subject the last mentioned to a voltage which causes the rate of change in speed reference voltage to be clamped to a rate which corresponds to the rate of change in motor speed if such reference voltage has not attained its preset magnitude.

Claim 6

In a D.C. motor control system, the combination with means for adjustably supplying energy to a motor armature, of control means for supplying the first mentioned means with a control voltage which is variable as a function of a speed reference voltage, a speed error feed back voltage and a voltage which varies with armature current, and comprising a. speed reference meeans including means for presetting a desired magnitude of speed reference voltage and means holding change of such voltage to a predetermined rate following changes in adjustment of said presetting means, b. speed error detector and integrator means providing an output voltage varying in accordance with the output voltage of said speed reference means and said speed error feed back voltage, c. current reference error detector means responsive to the last mentioned output voltage to provide an output voltage varying in accordance therewith, d. current integrator means in circuit with the first mentioned means and normally responsive to the resulted between the output voltage of said current reference error detector means and said voltage which varies with motor armature current to control the output of said first mentioned means in accordance therewith, e. current limit clamp means in circuit between the input to said current integrator means and the output of said current reference error detector means and being responsive to the output voltage of the latter means rising to or exceeding a preset value to clamp the input voltage from the latter means to said current integrator means to a value holding the motor armature current to a corresponding limited value, and f. timed reference rate clamp means in circuit with said current reference error detector means, said current limit clamp means, and said means holding change of said speed reference to a predetermined timed rate and responsive to said current limit clamp means clamping said input voltage to said current integrator means to subject the last mentioned to a voltage which causes the rate of change in speed reference voltage to be clamped to a rate which corresponds to the rate of change in motor speed if such reference voltage has not attained its preset magnitude.

Claim 7

The combination according to claim 4 wherein said control means further includes a spill-through circuit connected between the output of said speed error detector means and an input to said current reference error detector means, said spill-through circuit being responsive to rise in output voltage of said speed error detector means above a predetermined value to provide a step increase in system gain.

Claim 8

The combination according to claim 4 wherein said current limit clamp means comprises a transistor connected in an emitter follower configuration and having a preset base voltage, wherein a feed back resistor is connected between the current limit clamp means and the input to said current reference error detector means, and wherein a zener diode is connected across one diagonal of a full wave rectifier bridge which has its other diagonal connected at one side to the input of said means affording change in said speed reference voltage at a predetermined rate and its other side connected to the output of said current reference error detector means.