Method for controlling the motor of a synchronous reluctance motor for a pump and pump comprising a synchronous reluctance motor
First Claim
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1. A method for controlling the motor of a synchronous reluctance motor for a pump having a variable-frequency converter, comprising the acts of:
- controlling the synchronous reluctance motor using the variable-frequency converter in a volts/hertz operation,whereinthe variable-frequency converter operates in an open control circuit manner in which the variable-frequency converter does not use motor operating parameter feedback from the motor for closed-loop adjustment of motor operation,a ratio of a voltage supplied to the synchronous reluctance motor to a frequency of the variable-frequency converter in the volts/hertz operation is predetermined based on the synchronous reluctance motor being controlled by the variable-frequency converter,the variable-frequency converter in the volts/hertz operation controls a rotational speed of the motor,the ratio of the voltage to the frequency varies with voltage in a static-quadratic relationship which includes in a fixed voltage-frequency relationship in a rotation speed range between zero speed and a predetermined low speed threshold, and a quadratic voltage-frequency relationship in a rotation speed range above the predetermined low speed threshold,further comprising the acts of;
determining whether an anomaly state exists in which the at least one of the actual rotational speed of the motor and the process variable does not correspond to an expected state commanded by the variable-frequency converter in the volts/hertz operation, andinterrupting actuation of the synchronous reluctance motor by the variable-frequency converter in the volts/hertz operation for a predetermined period to reset control of the motor if the anomaly stated is determined to exist.
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Abstract
A method and apparatus for controlling the motor of a synchronous reluctance motor for a pump, in particular a centrifugal pump, are provided. The motor includes a variable-frequency drive which controls the synchronous reluctance motor in a terminal volts/hertz operation. The pump, in particular a centrifugal pump, includes at least one synchronous reluctance motor and a variable-frequency drive for a motor control, the variable-frequency drive being a terminal volts/hertz variable-frequency drive.
12 Citations
12 Claims
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1. A method for controlling the motor of a synchronous reluctance motor for a pump having a variable-frequency converter, comprising the acts of:
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controlling the synchronous reluctance motor using the variable-frequency converter in a volts/hertz operation, wherein the variable-frequency converter operates in an open control circuit manner in which the variable-frequency converter does not use motor operating parameter feedback from the motor for closed-loop adjustment of motor operation, a ratio of a voltage supplied to the synchronous reluctance motor to a frequency of the variable-frequency converter in the volts/hertz operation is predetermined based on the synchronous reluctance motor being controlled by the variable-frequency converter, the variable-frequency converter in the volts/hertz operation controls a rotational speed of the motor, the ratio of the voltage to the frequency varies with voltage in a static-quadratic relationship which includes in a fixed voltage-frequency relationship in a rotation speed range between zero speed and a predetermined low speed threshold, and a quadratic voltage-frequency relationship in a rotation speed range above the predetermined low speed threshold, further comprising the acts of; determining whether an anomaly state exists in which the at least one of the actual rotational speed of the motor and the process variable does not correspond to an expected state commanded by the variable-frequency converter in the volts/hertz operation, and interrupting actuation of the synchronous reluctance motor by the variable-frequency converter in the volts/hertz operation for a predetermined period to reset control of the motor if the anomaly stated is determined to exist. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A pump, comprising:
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a synchronous reluctance motor; a pump unit configured to be driven by the synchronous reluctance motor; and a controller having a variable-frequency converter configured to control the motor, wherein the variable-frequency converter is a volts/hertz variable-frequency converter, the variable-frequency converter is configured to operate in an open control circuit manner in which the variable-frequency converter does not use motor operating parameter feedback from the motor for closed-loop adjustment of motor operation, a ratio of a voltage supplied to the synchronous reluctance motor to a frequency of the variable-frequency converter in the volts/hertz operation is predetermined based on the synchronous reluctance motor being controlled by the variable-frequency converter, the variable-frequency converter in the volts/hertz operation is configured to control a rotational speed of the motor, the ratio of the voltage to the frequency varies with voltage in a static-quadratic relationship which includes in a fixed voltage-frequency relationship in a rotation speed range between zero speed and a predetermined low speed threshold, and a quadratic voltage-frequency relationship in a rotation speed range above the predetermined low speed threshold, the variable-frequency converter is configured to determine whether an anomaly state exists in which the at least one of the actual rotational speed of the motor and the process variable does not correspond to an expected state commanded by the variable-frequency converter in the volts/hertz operation, and interrupt actuation of the synchronous reluctance motor for a predetermined period to reset control of the motor if the anomaly stated is determined to exist. - View Dependent Claims (9, 10)
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11. A variable-frequency converter, comprising:
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a variable-frequency converter in a volts/hertz operation, wherein the variable-frequency converter is configured to control a synchronous reluctance motor to drive a pump unit in accordance with a setpoint rotational speed, the variable-frequency converter is configured to operate in an open control circuit manner in which the variable-frequency converter does not use motor operating parameter feedback from the motor for closed-loop adjustment of motor operation, a ratio of a voltage supplied to the synchronous reluctance motor to a frequency of the variable-frequency converter in the volts/hertz operation is predetermined based on the synchronous reluctance motor being controlled by the variable-frequency converter, the variable-frequency converter in the volts/hertz operation is configured to control a rotational speed of the motor, the ratio of the voltage to the frequency varies with voltage in a static-quadratic relationship which includes in a fixed voltage-frequency relationship in a rotation speed range between zero speed and a predetermined low speed threshold, and a quadratic voltage-frequency relationship in a rotation speed range above the predetermined low speed threshold, the variable-frequency converter is configured to determine whether an anomaly state exists in which the at least one of the actual rotational speed of the motor and the process variable does not correspond to an expected state commanded by the variable-frequency converter in the volts/hertz operation, and interrupt actuation of the synchronous reluctance motor for a predetermined period to reset control of the motor if the anomaly stated is determined to exist. - View Dependent Claims (12)
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Specification