Motor controller system and method for maximizing energy savings
First Claim
1. A system for controlling an AC induction motor to conserve energy, the system comprising:
- a processor that communicates with a computer-readable non-volatile memory having instructions stored thereon that, when executed by the processor, cause the processor to;
sweep a control space of said AC induction motor;
obtain operating parameters of said AC induction motor;
establish a control line from said measurements;
receive said control line at said motor controller;
perform a closed-loop control of said AC induction motor in accordance with said control line to observe an operating parameter;
drive the observed operating parameter of said AC induction motor relative to said control line, the observed operating parameter comprising a current;
detect zero-crossings of positive and negative halves of a current waveform of said AC induction motor every cycle by;
obtaining a positive voltage as a reference for a positive half cycle;
obtaining a negative voltage as a reference for a negative half cycle; and
transmitting signals through an OR gate to create composite current zero-cross digital signals.
2 Assignments
0 Petitions
Accused Products
Abstract
A motor controller (4) and method for maximizing the energy savings in an AC induction motor (3) at every load wherein the motor is calibrated at two or more load points to establish a control line (6), which is then programmed into a non-volatile memory (30) of the motor controller. A DSP-based closed-loop motor controller observes the motor parameters of the motor such as firing angle/duty cycles (23), voltage (37), current (9) and phase angles to arrive at a minimum voltage necessary to operate the motor at any load along the control line. The motor controller performs closed-loop control to keep the motor running at a computed target control point, such that maximum energy savings are realized by reducing voltage through pulse width modulation.
346 Citations
42 Claims
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1. A system for controlling an AC induction motor to conserve energy, the system comprising:
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a processor that communicates with a computer-readable non-volatile memory having instructions stored thereon that, when executed by the processor, cause the processor to; sweep a control space of said AC induction motor; obtain operating parameters of said AC induction motor; establish a control line from said measurements; receive said control line at said motor controller; perform a closed-loop control of said AC induction motor in accordance with said control line to observe an operating parameter; drive the observed operating parameter of said AC induction motor relative to said control line, the observed operating parameter comprising a current; detect zero-crossings of positive and negative halves of a current waveform of said AC induction motor every cycle by; obtaining a positive voltage as a reference for a positive half cycle; obtaining a negative voltage as a reference for a negative half cycle; and transmitting signals through an OR gate to create composite current zero-cross digital signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A system for controlling an AC induction motor to conserve energy, the system comprising:
a processor that communicates with a computer-readable non-volatile memory having instructions stored thereon that, when executed by the processor, cause the processor to; sweep a control space of said AC induction motor and measuring operating parameters of said AC induction motor; establish a control line from said measurements; receive said control line in said motor controller; perform a closed-loop control of said AC induction motor in accordance with said control line to observe an operating parameter; drive the observed operating parameter of said AC induction motor relative to said control line; protect against stalling of said AC induction motor by; actively controlling said AC induction motor while constantly monitoring said AC induction motor for increases in a motor current; turning a motor voltage to full on when an increase in said motor current is detected; and reducing said motor voltage to follow said control line after said motor current decreases.
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23. A method for controlling an AC induction motor to conserve energy, the method comprising the steps of:
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sweeping a control space of said AC induction motor and measuring operating parameters of said AC induction motor; establishing a control line for said AC induction motor from said measured operating parameters; receiving said control line at said motor controller; performing a closed-loop control of said AC induction motor in accordance with said control line to observe an operating parameter of said AC induction motor after the step of establishing said control line; driving the observed operating parameter of said AC induction motor relative to said control line; detecting zero-crossings of positive and negative halves of a current waveform in said AC induction motor every cycle; obtaining a positive voltage at a window comparator as a reference for a positive half cycle; obtaining a negative voltage at the window comparator as a reference for a negative half cycle; and transmitting signals from said window comparator through an OR gate to create composite current zero-cross digital signals. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30, 31, 32)
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33. A method for controlling an AC induction motor to conserve energy, the method comprising the steps of:
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sweeping a control space of said AC induction motor and measuring operating parameters of said AC induction motor; establishing a control line for said AC induction motor from said measured operating parameters; receiving said control line at said motor controller; performing a closed-loop control of said AC induction motor in accordance with said control line to observe an operating parameter of said AC induction motor after the step of establishing said control line; driving the observed operating parameter of said AC induction motor relative to said control line; increasing a firing angle/duty cycle of said AC induction motor from eighty degrees to one-hundred-fifty degrees; and recording a motor current and a phase angle along said control line.
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34. A method for controlling an AC induction motor to conserve energy, the method comprising the steps of:
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sweeping a control space of said AC induction motor and measuring operating parameters of said AC induction motor; establishing a control line for said AC induction motor from said measured operating parameters; receiving said control line at said motor controller; performing a closed-loop control of said AC induction motor in accordance with said control line to observe an operating parameter of said AC induction motor after the step of establishing said control line; driving the observed operating parameter of said AC induction motor relative to said control line; and protecting against stalling of said AC induction motor by; actively controlling said AC induction motor while constantly monitoring said AC induction motor for increases in a motor current; turning a motor voltage to full on when an increase in said motor current is detected; and reducing said motor voltage to follow said control line after said motor current decreases.
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35. A motor controller for controlling an AC induction motor to conserve energy, the motor controller comprising:
a processor that communicates with a computer-readable non-volatile memory having instructions stored thereon that, when executed by the processor, cause the processor to; compute a control line from measured operating parameters; perform a closed-loop control of the AC induction motor in accordance with said computed control line to observe an operating parameter of the AC induction motor; drive the observed operating parameter of the AC induction motor relative to said computed control line; detect zero-crossings of positive and negative halves of a current waveform in the AC induction motor by; obtaining a positive voltage as a reference for a positive half cycle; obtaining a negative voltage as a reference for a negative half cycle; and transmitting signals through an OR gate to create composite current zero-cross digital signals. - View Dependent Claims (36, 37, 38, 39, 40, 41, 42)
Specification