Method and Arrangement for Reducing the Torque Ripple of a DC Motor
First Claim
1. A method for reducing the torque ripple of a brushless DC motor with a stator, a rotor and a motor control unit by which the motor is controlled in a polyphase manner, with a data memory for storing correction data of the control current of the motor, which data is a function of the angle of rotation, in which correction data is impressed on the instantaneous values for controlling the motor, whereinin a first step for each position of the rotor phase, currents holding the rotor in this position are determined from which reference current data is derived which is stored in a table of the data memory together with the particular position data of the rotor which is determined by a position sensor, andin a second step during the running operation of the motor the position-dependent reference current data filed in the data memory is linked with the control current of the motor in such a manner that the original torque ripple of the motor is canceled or reduced.
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Accused Products
Abstract
The invention relates to a method and to an arrangement for reducing the torque ripple of a brushless DC motor (6) having a stator, a rotor, and a motor control unit, via which motor control unit the motor is controlled in a polyphase manner, having a data memory (1) for storing rotational angle-dependent correction data of the control current of the motor (6), which are impressed on the instantaneous values for controlling the motor. According to the invention, in a first step, for each position of the rotor, the phase currents holding the rotor in this position are determined and are used to derive reference current data, which is stored in a table of the data memory (19) together with the respective position data of the rotor, determined by the position sensor, and, in a second step, during continuous operation of the motor, the position-dependent reference current data stored in the data memory is combined with the control current of the motor. In a preferred refinement of the invention, the reference current data is conditioned in such a way that both outliers and noise are removed.
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Citations
11 Claims
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1. A method for reducing the torque ripple of a brushless DC motor with a stator, a rotor and a motor control unit by which the motor is controlled in a polyphase manner, with a data memory for storing correction data of the control current of the motor, which data is a function of the angle of rotation, in which correction data is impressed on the instantaneous values for controlling the motor, wherein
in a first step for each position of the rotor phase, currents holding the rotor in this position are determined from which reference current data is derived which is stored in a table of the data memory together with the particular position data of the rotor which is determined by a position sensor, and in a second step during the running operation of the motor the position-dependent reference current data filed in the data memory is linked with the control current of the motor in such a manner that the original torque ripple of the motor is canceled or reduced.
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7. An arrangement for controlling a brushless DC motor for detecting and compensating a torque ripple of the motor with a stator and a rotor by a motor control unit with which the motor can be controlled in a polyphase manner, with a position sensor on the motor rotor for detecting the instantaneous relative or absolute position of the rotor, and with a data memory for storing rotational angle-dependent correction data of the control current of the motor which can be impressed on the instantaneous values for controlling the motor, wherein
at least two current sensors are provided for detecting the phase currents of the rotor, the phase currents for controlling the motor can be determined in rotational angle-dependent positions of the rotor and can be stored as position-related reference current values in the data memory, and the reference current values can be read out from the data memory in the running operation of the motor and can be impressed on the control current for controlling the motor.
Specification