Motor drive device, brushless motor, and motor drive method
AssigneePanasonic Corporation
InventorDaisuke Sato
Life of this patent
Estimating the term…
Abstract
The disclosed device comprises a duty calculator for calculating a duty command value (Dty), a duty limiter for limiting the duty command value (Dty) to a value according to a limit value (L), a current flow monitor for determining that there is an overcurrent if a current value (Idet) flowing through a winding exceeds a predetermined threshold value (Ithr), and a limit value generator for generating the limit value (L). The limit value generator updates the limit value (L) at predetermined time intervals and for a value corresponding to a difference between the threshold value (Ithr) and the current value (Idet) at a time in order to decrease the current value (Idet) during a period in which the overcurrent is determined.
Claims15
A motor drive device for controlling rotational operation of a motor by using a pulse-width modulated PWM signal, the device comprising:
- a drive controller for generating a driving signal to drive the motor;
- a duty calculator for calculating a duty command value corresponding to the driving signal;
- a duty limiter for limiting the duty command value to a value according to a limit value;
- a PWM signal generator for generating the PWM signal of a duty factor corresponding to an output value of the duty limiter;
- a drive output unit for generating an energizing signal corresponding to the PWM signal, and energizing a winding of the motor with the energizing signal;
- a current flow monitor for monitoring a current value that flows through the winding, and determining the current value as being an overcurrent when the current value exceeds a predetermined threshold value;
- and
- a limit value generator for generating the limit value,
- wherein the limit value generator updates the limit value at predetermined time intervals and for a value corresponding to a difference between the threshold value and the current value at a time, in order to decrease the current value during a period in which the overcurrent is determined.
A motor drive method for driving and controlling rotational operation of a motor by using a pulse-width modulated PWM signal, the method comprising the steps of:
- generating a driving signal to drive the motor;
- calculating a duty command value corresponding to the driving signal;
- limiting the duty command value to a value according to a limit value;
- generating the PWM signal of a duty factor corresponding to an output value provided in the step of limiting by the limit value;
- generating an energizing signal corresponding to the PWM signal and energizing a winding of the motor with the energizing signal;
- monitoring a current value that flows through the winding and determining the current value as being an overcurrent if the current value exceeds a predetermined threshold value;
- and
- generating the limit value,
- wherein the step of generating the limit value is to update the limit value at predetermined time intervals and for a value corresponding to a difference between the threshold value and the current value at a time, in order to decrease the current value during a period in which the overcurrent is determined.
Dependencies are inferred from the claim text.