Device and a method for estimating the speed of a slip ring asynchronous machine
First Claim
1. A device for estimating the rotor speed of at least one slip ring asynchronous machine, the asynchronous machine including a stator having a stator winding fed with three-phase voltage and current in order to generate a varying magnetic flux having a rotation speed, and a rotor having a rotor winding in which the magnetic flux generated by the stator winding induces a voltage in the rotor winding, thereby creating an electromagnetic torque which drives the rotor at a rotor speed such that the rotor speed has a slip in relation to the rotation speed of the varying magnetic flux, the device comprising:
- a measuring member arranged to measure the voltage in the rotor winding during at least one time period and to output a signal corresponding to the measured voltage in the rotor winding;
a signal processor having a digital signal processor unit arranged to remove noise from a digital signal corresponding to the measured voltage in the rotor winding and to generate an output signal; and
a calculating unit arranged to receive the output signal from the signal processor and to calculate a value of the rotor speed based on the output signal.
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Accused Products
Abstract
The invention relates to a device and a method for estimating the speed of a slip ring asynchronous machine. The asynchronous machine includes a stator having a stator winding, arranged to be fed with three-phase voltage and current in order to generate a varying magnetic flux, and a rotor having a rotor winding in which the magnetic flux is arranged to induce a voltage to create an electromagnetic torque. The device includes a measuring member arranged to measure the value of the voltage in the rotor winding during at least one time period and a calculating unit, which is arranged, using the above measured voltage, to calculate a value of the rotor speed.
33 Citations
17 Claims
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1. A device for estimating the rotor speed of at least one slip ring asynchronous machine, the asynchronous machine including a stator having a stator winding fed with three-phase voltage and current in order to generate a varying magnetic flux having a rotation speed, and a rotor having a rotor winding in which the magnetic flux generated by the stator winding induces a voltage in the rotor winding, thereby creating an electromagnetic torque which drives the rotor at a rotor speed such that the rotor speed has a slip in relation to the rotation speed of the varying magnetic flux, the device comprising:
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a measuring member arranged to measure the voltage in the rotor winding during at least one time period and to output a signal corresponding to the measured voltage in the rotor winding; a signal processor having a digital signal processor unit arranged to remove noise from a digital signal corresponding to the measured voltage in the rotor winding and to generate an output signal; and a calculating unit arranged to receive the output signal from the signal processor and to calculate a value of the rotor speed based on the output signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for estimating the rotor speed of a slip ring asynchronous machine, the asynchronous machine including a stator having a stator winding fed with three-phase voltage and current in order to generate a varying magnetic flux having a rotation speed and a rotor having a rotor winding in which the magnetic flux generated by the stator winding induces a voltage in the rotor winding, thereby creating an electromagnetic torque which drives the rotor at a rotor speed such that the rotor speed has a slip in relation to the rotation speed of the varying magnetic flux, the method comprising the steps of:
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measuring the voltage in the rotor winding during at least a time period and outputting a signal corresponding to the measured voltage in the rotor winding; and removing noise from a digital signal corresponding to the measured voltage in the rotor winding; and calculating a value of the rotor speed by means of the above measured voltage. - View Dependent Claims (12, 13, 14, 15)
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16. A method for controlling one or more asynchronous machines, which machines each include a stator having a stator winding arranged to be fed with three-phase voltage and current in order to generate a varying magnetic flux and a rotor having a rotor winding in which the magnetic flux is arranged to induce a voltage to create an electromagnetic torque which drives the rotor with a rotor speed with a slip in relation to a rotation speed of the varying magnetic flux, the method comprising the steps of:
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measuring a value of the voltage in the rotor winding using a measuring member, during at least one time period; outputting a signal corresponding to the value of the measured voltage; removing noise from a digital signal corresponding to the value of the measured voltage using a signal processor that includes a digital signal processor unit; and calculating a value of the rotor speed with a calculating unit that utilizes an output signal from the signal processor. - View Dependent Claims (17)
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Specification