Back to results
US 8,760,089 B2Granted
Variable speed drive system
AssigneeFranklin Electric Co., Inc.
InventorRobert C. Smith
Life of this patent
Estimating the term…
Abstract
This disclosure relates to a control system for driving a motor. The motor may include a cut-out circuit. The control system may include a buck-boost circuit to limit the rate of change of an output voltage before the output voltage is applied to operate the motor.
Claims65
A fluid displacement system comprising:
- a pump for displacing a fluid;
- a motor drivingly connected to the pump;
- a plurality of power switches;
- and
- a controller generating a first plurality of switching signals and a second plurality of switching signals to switch the plurality of power switches, the first plurality of switching signals provided to the plurality of power switches when a commutation angle of the motor comprises at least one of a first angle and an angle proximal to the first angle, the second plurality of switching signals provided to the plurality of power switches when the commutation angle comprises at least one of a second angle and an angle proximal to the second angle, the first plurality of switching signals having a first maximum switching frequency which is higher than a second maximum switching frequency of the second plurality of switching signals.
2 more elements
A fluid displacement system comprising:
- a pump for displacing a fluid;
- a motor drivingly connected to the pump, the motor comprising a cut-out circuit including a cut-out power switch having a maximum voltage rate of change;
- a plurality of power switches to drive the motor, the power switches producing a voltage rate of change exceeding a predetermined voltage rate of change corresponding to the maximum voltage rate of change of the cut-out power switch;
- and
- a buck-boost circuit coupled between the plurality of power switches and the motor to limit the voltage rate of change produced by the power switches below the predetermined voltage rate of change to prevent false-triggering of the cut-out power switch.
2 more elements
A control system for driving a motor, the motor comprising a cut-out circuit including a cut-out power switch having a maximum voltage rate of change, the control system comprising:
- a plurality of power switches producing a voltage rate of change exceeding a predetermined voltage rate of change corresponding to the maximum voltage rate of change of the cut-out power switch;
- and
- a buck-boost circuit coupled between the plurality of power switches and the motor to limit the voltage rate of change produced by the power switches below the predetermined voltage rate of change to prevent false-triggering of the cut-out power switch.
A control system for driving a motor, the control system comprising:
- a plurality of power switches producing a motor voltage having a voltage rate of change;
- and
- a controller generating a first plurality of switching signals and a second plurality of switching signals to drive the motor, the first plurality of switching signals generated when a commutation angle of the motor comprises at least one of a first angle and an angle proximal to the first angle, the second plurality of switching signals generated when the commutation angle comprises at least one of a second angle and an angle proximal to the second angle, the first plurality of switching signals having a first maximum switching frequency which is higher than a second maximum switching frequency of the second plurality of switching signals.
A control system for driving a motor, the motor comprising a cut-out circuit including a cut-out power switch having a maximum voltage rate of change, the control system comprising:
- voltage generation means for providing a voltage having a voltage rate of change corresponding to the maximum voltage rate of change of the cut-out power switch;
- and
- circuit means coupled between the voltage generation means and the motor for reducing the voltage rate of change produced by the voltage generation means to prevent false-triggering of the cut-out power switch.
A control system for driving a motor, the control system comprising:
- voltage generation means for providing a voltage having a voltage rate of change;
- and
- control means for generating a first plurality of switching signals and a second plurality of switching signals, the first plurality of switching signals provided when a commutation angle of the motor comprises at least one of a first angle and an angle proximal to the first angle, the second plurality of switching signals provided when the commutation angle comprises at least one of a second angle and an angle proximal to the second angle, the first plurality of switching signals having a first maximum switching frequency which is higher than a second maximum switching frequency of the second plurality of switching signals.
A method of driving a motor, the motor comprising a cut-out circuit including a cut-out power switch having a maximum voltage rate of change, the method comprising:
- switching a plurality of power switches to generate an output voltage having a rate of change exceeding a predetermined rate of change, the predetermined rate of change corresponding to the maximum voltage rate of change of the cut-out power switch;
- and
- reducing the rate of change of the output voltage to produce motor voltage with a motor voltage rate of change below the predetermined rate of change to prevent false-triggering of the cut-out power switch.
A method of driving a motor, the method comprising:
- generating a first plurality of switching signals and a second plurality of switching signals, the first plurality of switching signals generated when a commutation angle of the motor comprises at least one of a first angle and an angle proximal to the first angle, the second plurality of switching signals generated when the commutation angle comprises at least one of a second angle and an angle proximal to the second angle, the first plurality of switching signals having a first maximum switching frequency which is higher than a second maximum switching frequency of the second plurality of switching signals;
- and
- switching a plurality of power switches with the first plurality of switching signals and the second plurality of switching signals to generate an output voltage.
A method of driving a motor, the method comprising:
- powering the motor according a first fundamental voltage/frequency relationship;
- detecting a current decrease of a fundamental current drawn by the motor;
- and
- upon detecting the current decrease, defining a frequency threshold based on a frequency at which the current decrease occurred;
- and
- after detecting the current decrease, powering the motor according to a second fundamental voltage/frequency relationship.
3 more elements
A control system for driving a motor, the control system comprising:
- a plurality of power switches producing a fundamental voltage;
- and
- a controller operably coupled to the plurality of power switches, the controller generating a first plurality of switching signals according to a first fundamental voltage/frequency relationship, detecting a current decrease of a fundamental current drawn by the motor, and after detecting the current decrease, generating a second plurality of switching signals according to a second fundamental voltage/frequency relationship.
Dependencies are inferred from the claim text.