Controlling electronically commutated motor
AssigneeDeutsche Thomson-Brandt GmbH
InventorGunter Gleim
Life of this patent
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Abstract
An electronically commutated motor is controlled by controlling the winding current of the motor. During an operational mode change of the motor, the winding current is first changed to a value in excess of the value needed to maintain a measured motor parameter at a desired level. When the desired level of the parameter is reached the current is changed to the value needed to maintain the parameter at the desired level. In addition, the communication time of the motor is shifted such that the temporal maximum of the magnetic field of the motor coincides with the position of the motor poles which results in attainment of a maximum speed altering force.
Claims21
A method for controlling an electronically commutated motor by controlling the winding current of said motor, wherein during an operational mode change of said motor said winding current is first changed to a value in excess of the value needed to maintain a motor parameter at a desired level until the desired level of the parameter is reached, and then said winding current is changed to the value needed to maintain said parameter at said desired level, an improvement comprising the steps of:
- shifting the commutation time of said motor such that the temporal maximum of the magnetic field of said motor coincides with the position of the motor poles which results in attainment of a maximum parameter altering force:
- generating and storing control values in accordance with changes in said parameter during said operational mode changes;
- monitoring said parameter during normal operation of said motor and generating additional values in accordance with changes in said parameter;
- storing said additional values;
- and,
- extrapolating said stored values and providing a corrected parameter.
A method for controlling an electronically commutated motor by controlling the winding current of said motor, wherein during an operational mode change of said motor said winding current is first changed to a value in excess of the value needed to maintain a motor parameter at a desired level until the desired level of the parameter is reached, and then said winding current is changed to the value needed to maintain said parameter at said desired level, an improvement comprising the step of shifting the commutation time of said motor such that the temporal maximum of the magnetic field of said motor coincides with the position of the motor poles which results in attainment of a maximum parameter altering force, wherein said parameter is one of acceleration, deceleration, and load changes.
In a system for controlling an electronically commutated motor, said system including a generator for providing commutation signals to a commutation circuit, controllable output stages responsive to said commutation signals for varying the winding current of said motor, and a variable delay for providing a correction variable for selectively delaying said commutation signals, an improvement comprising:
- a measuring circuit for measuring a parameter of said motor and providing measured values;
- a control circuit responsive to said measured values for providing a control variable to control said correction variable in response to changes in said parameter;
- and,
- computer means responsive to said commutation signals for controlling said controllable output stages in accordance with said commutation signals.
A method for controlling commutation times in an electronically commutated motor as operating levels of motor parameters change during such motor operating modes as acceleration, deceleration and compensation for load variation, comprising the steps of:
- storing a plurality of control values for optimizing said commutation times of said motor at different operating levels of at least one of said motor parameters in at least one of said operating modes;
- successively selecting different ones of said stored control values in accordance with said changing operating levels of said at least one motor parameter during said at least one operating mode;
- and,
- successively changing said commutation times of said motor in accordance with said succession of said selected control values to optimize said commutation times of said motor during said at least one operating mode.
An apparatus for controlling commutation times in windings of an electronically commutated motor in such operating modes as acceleration, deceleration and compensation for load variation, comprising:
- a generator for picking up signals used for commutation;
- a commutation circuit;
- controllable output stages, switched by said commutation circuit, for providing a variable current to said motor windings;
- a variable delay element coupled between said generator and said commutation circuit and having a control input;
- and,
- control means for deriving a correction variable from a value of desired winding current and a value of an actual winding current and supplying said correction variable to said control input of said delay element for controllably delaying said commutation time.
Dependencies are inferred from the claim text.