Electronic digitized proportional-integral controller
AssigneeOce-Nederland B.V.
InventorWilhelmus T. L. Bisseling
Life of this patent
Estimating the term…
Abstract
A digital proportional-integral controller for controlling the speed of a d.c. electric motor in a copying machine and synchronizing it with the speed of another motor in the copying machine. The proportional stage and the integral stage of the controller are each formed by an up/down counter which counts up or down depending upon the pulses of the actual speed signal and the reference signal. Logic circuits are provided for processing the speed signal pulses and the reference signal pulses before they are fed to the up/down counters. The controller also has an interface for a two-wire bus system over which data and commands for adjusting and varying the control parameters can be input.
Claims16
An electronic proportional-integral controller for controlling the speed of an electric motor in accordance with a reference signal whose frequency represents the desired output speed of the controlled electric motor and a speed signal whose frequency represents the actual output speed of the controlled electric motor, comprising:
- (a) a proportional circuit for generating a P-control signal corresponding to the difference between the frequencies of the reference signal and the speed signal and wherein the proportional circuit comprises a logic circuit connected to an up/down counter such that the logic circuit:
- (1) converts the speed signal into a standardized speed signal which changes its state on each rising flank of the speed signal;
- (2) converts the reference signal into a standardized reference signal which changes its state on each rising flank of the reference signal;
- (3) delivers a sequence of upward counting pulses to the counter in synchronism with a first clock signal when there is present a pulse of the standardized speed signal and no pulse of the standardized reference signal;
- (4) delivers a sequence of downward counting pulses to the counter in synchronism with the first clock signal when there is present a pulse of the standardized reference signal and no pulse of the standardized speed signal;
- (5) generates a read signal to output the value of the counter which is the P-control signal;
- and
- (6) generates a reset signal to reset the counter if a pulse has occurred in both the standardized speed signal and in the standardized reference signal and both standardized signals simultaneously have a pulse break;
- (b) an integrator circuit which uses the speed signal and the reference signal for generating an I-control signal corresponding to the time integral of the difference between the frequencies of the reference signal and the speed signal;
- (c) an addition circuit connected to both the proportional circuit and the integrator circuit for generating a sum signal corresponding to the sum or the weighted sum of the P-control and I-control signals;
- and
- (d) an output stage for controlling the motor in accordance with the sum signal of the addition circuit.
An electronic proportional controller for controlling the speed of an electric motor in accordance with a reference signal whose frequency represents the desired output speed of the controlled electric motor and a speed signal whose frequency represents the actual output speed of the controlled electric motor, comprising:
- (a) a proportional circuit for generating a P-control signal corresponding to the difference between the frequencies of the reference signal and the speed signal and wherein the proportional circuit comprises a logic circuit connected to an up/down counter such that the logic circuit:
- (1) converts the speed signal into a standardized speed signal which changes its state on each rising flank of the speed signal;
- (2) converts the reference signal into a standardized reference signal which changes its state on each rising flank of the reference signal;
- (3) delivers a sequence of upward counting pulses to the counter in synchronism with a first clock signal when there is present a pulse of the standardized speed signal and no pulse of the standardized reference signal;
- (4) delivers a sequence of downward counting pulses to the counter in synchronism with the first clock signal when there is present a pulse of the standardized reference signal and no pulse of the standardized speed signal;
- (5) generates a read signal to output the value of the counter which is the P-control signal;
- and
- (6) generates a reset signal to reset the counter if a pulse has occurred in both the standardized speed signal and in the standardized reference signal and both standardized signals simultaneously have a pulse break;
- (b) an addition circuit connected to the proportional circuit for generating a sum signal corresponding to a predetermined weighting of the P-control signal;
- and
- (c) an output stage for controlling the motor in accordance with the sum signal of the addition circuit.
an electronic integral controller for controlling the speed of an electric motor in accordance with a reference signal whose frequency represents the desired output speed of the controlled electric motor and a speed signal whose frequency represents the actual output speed of the controlled electric motor, comprising:
- (a) an integrator circuit for generating an I-control signal corresponding to the time integral of the difference between the frequencies of the reference signal and the speed signal and wherein the integrator circuit comprises a logic circuit connected to an up/down counter such that the logic circuit:
- (1) delivers an upward counting pulse to the counter on each rising flank of the speed signal;
- (2) delivers a downward counting pulse to the counter on each rising flank of the reference signal;
- (3) generates a read signal after one cycle of the speed signal and the reference signal to output the value of the counter which is the I-control signal;
- (b) an addition circuit connected to the integrator circuit for generating a sum signal corresponding to a predetermined weighting of the I-control signal;
- and
- (c) an output stage for controlling the motor in accordance with the sum signal of the addition circuit.
Dependencies are inferred from the claim text.