Semiconductor device, motor drive system, and motor control program
AssigneeRenesas Electronics Corporation
InventorSatoshi Narumi
Life of this patent
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Abstract
The present disclosure starts up a three-phase motor in a stable manner. During a start-up operation of a brushless DC motor, a motor drive system detects the position of a particularly suitable rotor while the rotor is resting, and applies a drive current to two phases in accordance with the detected position of the rotor. A controller changes the time of drive current application in accordance with the magnitude of back electromotive force that is in a non-conducting phase and detected by a detector during drive current application.
Claims16
A semiconductor device adapted to control an inverter circuit that drives a three-phase motor, the semiconductor device comprising:
- a detector that is coupled to output nodes in various phases of the inverter circuit adapted to output a motor voltage, and detects back electromotive force generated in an output node that is in a non-conducting phase and among the output nodes of the various phases;
- and
- a controller that controls the inverter circuit,
- wherein the controller detects a position of a rotor in the three-phase motor during a start-up operation of the three-phase motor, and controls the inverter circuit so as to apply a drive current to two out of three phases of the three-phase motor in accordance with the detected position of the rotor,
- wherein the controller changes a time of application of the drive current in accordance with a rotation speed of the rotor, and
- wherein the controller changes the time of application of the drive current in accordance with a magnitude of the back electromotive force that is in a non-conducting phase and detected by the detector.
A motor drive system comprising:
- a three-phase motor;
- an inverter circuit that drives the three-phase motor;
- and
- a semiconductor device that controls the inverter circuit,
- wherein the semiconductor device includes
- a detector that is coupled to output nodes in various phases of the inverter circuit adapted to output a motor voltage, and detects back electromotive force generated in an output node that is in a non-conducting phase and among the output nodes of the various phases, and
- a controller that controls the inverter circuit,
- wherein the controller detects a position of a rotor in the three-phase motor during a start-up operation of the three-phase motor, and controls the inverter circuit so as to apply a drive current to two out of three phases of the three-phase motor in accordance with the detected position of the rotor,
- wherein the controller changes a time of application of the drive current in accordance with a rotation speed of the rotor, and
- wherein the controller changes the time of application of the drive current in accordance with a magnitude of the back electromotive force that is in a non-conducting phase and detected by the detector.
A motor control computer-readable storage medium that causes a computer to execute the steps of:
- detecting a position of a rotor in a three-phase motor by performing inductive sensing during a start-up operation of the three-phase motor;
- starting to apply a drive current to two out of three phases of the three-phase motor by an inverter circuit in accordance with the detected position of the rotor during a start-up operation of the three-phase motor;
- and
- stopping application of the drive current by the inverter circuit in accordance with a rotation speed of the rotor and a magnitude of back electromotive force that is in a non-conducting phase and detected during the application of the drive current.
Dependencies are inferred from the claim text.