Solid state controller
First Claim
1. A control system using a power supply for positioning a device associated with a physical variable wherein the position of the device is controlled by an alternating current electric prime mover driven by an alternating current source and the position of the device is represented by a state signal whose variable amplitude is a function of the position, comprising:
- means responsive to the physical variable for generating a reference input signal of settable magnitude representing a desired position of the device;
a first wave form generating means for generating an electrical generated signal;
difference means responsive to the state signal, said reference signal and said electrical generated signal for simultaneously generating at least one variable error signal having a magnitude and polarity only proportional to a difference relationship between the magnitudes of the state signal and said refernce signal over time and at least one generated error signal having a magnitude and polarity proportional to the relationship between said variable error signal and said electrical generated signal;
said error signals having waveforms differing from said electrical waveform, and said electrical generated signal and said error signals being coordinated in time;
comparator means responsive to said difference means and said first waveform generating means for producing first variable duration output pulses at a plurality of outputs;
said variation of duration being a function in time of the magnitude of said electrical generated signal and said variable error signal, said difference means being electrically connected between the state signal and said reference signal and said comparator means, and said first waveform generating means being electrically connected between said comparator means and the power supply; and
a solid state switching means responsive to said outputs of said comparator means for switching power to the alternating current electric prime mover to vary the position of the device, said solid state switching means being electrically connected between said comparator means and the alternating current electric prime mover and the alternating current source.
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Accused Products
Abstract
An improved alternating current prime mover control system and method for, for example, the control of a valve position or other physical variable whose state can be sensed or calculated wherein the state of the physical variable is compared with a reference variable to generate, in conjunction with a waveform generator, a fixed amplitude signal that has variable time duration which feeds a part of the control system that drives the alternating current prime mover source in more than one direction.
20 Citations
28 Claims
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1. A control system using a power supply for positioning a device associated with a physical variable wherein the position of the device is controlled by an alternating current electric prime mover driven by an alternating current source and the position of the device is represented by a state signal whose variable amplitude is a function of the position, comprising:
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means responsive to the physical variable for generating a reference input signal of settable magnitude representing a desired position of the device; a first wave form generating means for generating an electrical generated signal; difference means responsive to the state signal, said reference signal and said electrical generated signal for simultaneously generating at least one variable error signal having a magnitude and polarity only proportional to a difference relationship between the magnitudes of the state signal and said refernce signal over time and at least one generated error signal having a magnitude and polarity proportional to the relationship between said variable error signal and said electrical generated signal;
said error signals having waveforms differing from said electrical waveform, and said electrical generated signal and said error signals being coordinated in time;comparator means responsive to said difference means and said first waveform generating means for producing first variable duration output pulses at a plurality of outputs;
said variation of duration being a function in time of the magnitude of said electrical generated signal and said variable error signal, said difference means being electrically connected between the state signal and said reference signal and said comparator means, and said first waveform generating means being electrically connected between said comparator means and the power supply; anda solid state switching means responsive to said outputs of said comparator means for switching power to the alternating current electric prime mover to vary the position of the device, said solid state switching means being electrically connected between said comparator means and the alternating current electric prime mover and the alternating current source. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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28. A method of controlling the state of a physical variable, comprising the steps of:
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generating a reference signal representing the desired state of a device controlling the state of the physical variable proportional in magnitude and polarity to a relationship between the desired state of the physical variable and the current state of the physical variable; generating an error signal proportional in magnitude and polarity to a relationship between the state of the device and the reference signal; generating a first time proportional signal responsive to said error signal and a first time variable signal such that the duration of the first time proportional signal is a function of a relationship between the state of the device and the reference signal; time proportionating said first time proportional signal to produce a second time proportional signal whose presence is a function of said first time proportional signal and whose degree of time proportionation is a function of a second time variable signal for varying the rate of change of the state of the device, and controlling the device capable of altering the state of the physical variable with the second time proportional signal.
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Specification