Motor control system with linear acceleration circuit

Claim 2

An energizing system for an electrical motor in which electrical energy is passed to the motor through a power circuit including at least one semiconductor power switch, comprising: a control amplifier having an input connection, and having an output connection connected to regulate operation of the semiconductor power switch and thus regulate energization of said motor, adjustable reference means, connected to provide a speed reference signal which varies as said reference means is adjusted, and a linear acceleration stage, coupled between said adjustable reference means and the control amplifier input connection, including an operational amplifier connected to provide a switching signal as the adjustable reference means is varied to signal a speed increase, a charging circuit including a capacitor coupled to the operational amplifier to charge and provide a smooth speed change signal for application to the control amplifier input connection, and a first semiconductor switch, connected to disable the charging circuit until the switching signal is provided by the operational amplifier, and to rapidly discharge the capacitor as the adjustable reference means is varied to signal a speed decrease.

Claim 3

A motor energizing system as claimed in claim 1 in which a supply voltage is applied to said charging circuit, which supply voltage is larger by at least an order of magnitude than the voltage developed across said capacitor to represent the smooth speed change signal, to insure that only the initial portion of the capacitor-charging waveform is applied to the control amplifier and provide a linear ramp output signal in response to a step function input signal received by the linear acceleration stage.

Claim 4

A motor energizing system as claimed in claim 1 in which said operational amplifier includes a pair of input terminals and an output terminal, circuit means completing a negative feedback between the output terminal and one of the input terminals, and means for applying the speed reference signal to the other input terminal, such that the ramp increase in the smooTh speed change signal is terminated by comparing the smooth speed change signal with the speed reference signal over the negative feedback path.

Claim 5

A motor energizing system as claimed in claim 1 in which said linear acceleration stage includes a second semiconductor switch, coupled between said capacitor and the output conductor for applying the output signal from the linear acceleration stage to the control amplifier.

Claim 6

A motor energizing system as claimed in claim 4, in which both said first and second transistors have base, emitter and collector elements, the base of the first transistor being coupled to the output side of the operational amplifier, the emitter of the first transistor being coupled to a reference conductor, the collector of said first transistor being coupled to the common connection between said capacitor and at least one resistance component in the charging circuit, such that the emitter-collector path of the first transistor is coupled directly in parallel with said capacitor, the base of said second transistor being coupled to the collector of said first transistor and to one plate of said capacitor, the collector of said second transistor being connected to receive an energizing potential, and the emitter of the second transistor being coupled over the output conductor to the control amplifier.

Claim 7

A motor energizing system as claimed in claim 5 and further comprising a series circuit, including a first resistor and a diode, coupled between said output conductor and said reference conductor, means including a second resistor coupled to the common connection between said first resistor and diode in the series circuit, for applying a potential to said series circuit to complete the energizing path for said second transistor.

Claim 8

An energizing system for a DC electrical motor in which electrical energy is passed to the motor through a power circuit including a plurality of SCR''s regulated by a corresponding plurality of firing circuits, comprising: a control amplifier stage having an input circuit, and having an output circuit connected to regulate operation of the firing circuits and thus regulate energization of the motor, a potentiometer, connected to provide a speed reference signal which varies as the setting of said potentiometer is adjusted, and a linear acceleration stage, including an operational amplifier having a first input terminal, a second input terminal coupled to said potentiometer, and an output terminal for providing a switching signal as the potentiometer is adjusted to signal a speed increase, a charging circuit including a resistor and a capacitor coupled in series between an energizing connection and a reference conductor such that charging of the capacitor provides a smooth speed change signal for application over an output conductor to the control amplifier stage, and a transistor, having a base coupled to the control amplifier output terminal, and having its collector and emitter coupled to opposite plates of said capacitor, said transistor being normally biased for conduction to disable the charging circuit until the switching signal is provided by the operational amplifier to turn off the transistor and allow the capacitor to charge, and which transistor is rapidly gated on when the motor speed reaches the desired speed, to rapidly discharge the capacitor.

Claim 9

An energizing system for a DC electrical motor in which electrical energy is passed to the motor through a power circuit including a plurality of SCR''s regulated by a corresponding plurality of firing circuits, comprising: a control amplifier stage having an input circuit, and having an output circuit connected to regulate operation of the firing circuits and thus regulate energization of the motor, a potentiometer, connected to provide a speed reference signal which varies as the setting of said potentiometer is adjusted, and a linear acceleration stage, including an operational amplifier having a first input terminal, a second input terminal coupled to said potentiometer, and an output terminal for providing a switching signal as the potentiometer is adjusted to signal a speed increase, a charging circuit including a resistor and a capacitor coupled in series between an energizing connection and a reference conductor such that charging of the capacitor provides a smooth speed change signal for application over an output conductor to the control amplifier stage, and a transistor, having a base coupled to the control amplifier output terminal, and having its collector and emitter coupled to opposite plates of said capacitor, said transistor being normally biased for conduction to disable the charging circuit until the switching signal is provided by the operational amplifier to turn off the transistor and allow the capacitor to charge, and which transistor is rapidly gated on when the motor speed reaches the desired speed, to rapidly discharge the capacitor.

Claim 10

A motor energizing system as claimed in claim 7 in which a resistor is coupled between the first input terminal of the operational amplifier and the capacitor to complete a negative feedback path, such that the ramp increase in the smooth speed change signal developed by charging of the capacitor is terminated by comparing the smooth speed change signal with the speed reference signal over the negative feedback path.