Brushless-motor driver in PWM mode
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsToshiaki Seima, Yoshiaki Iwayama
Life of this patent
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Abstract
In a driver of a brushless motor performing synchronous rectification PWM operation, switching is performed at an arbitrary timing between a synchronous rectification PWM operation and one-way PWM operation to prevent a negative current for the power supply, and thus preventing increase of a power supply voltagedue to the negative current, thereby implementing high performance and high reliability.
Claims8
A motor driver for driving a brushless motor having a plurality of driving coils, comprising:
- a pair of an upper drive section and a lower drive section operatively connected to said driving coils for operating the brushless motor in a plurality of operation modes including a synchronous rectification PWM mode and a one-way PWM mode;
- and
- a switching controller for controllably switching the PWM modes between the synchronous rectification PWM mode and the one-way PWM mode in a phase-switching timing period;
- wherein the PWM operation mode is switched to perform the one-way PWM operation mode during a deceleration period in operating the brushless motor, and the synchronous rectification PWM mode is performed in a non-deceleration period thereof, to thereby switch a regeneration current flowing path.
A motor driver for driving a brushless motor which includes a rotor magnet and driving coils disposed to oppose said rotor magnet, comprising:
- upper drive means constituted of a plurality of drive elements which are connected to said driving coils and are provided on one power supply line;
- lower drive means constituted of a plurality of drive elements which are connected to said driving coils and are provided on another power supply line;
- position detector means for detecting a positional relationship between said rotor magnet and said driving coils;
- commutation switching means for generating a commutation switching signal to be supplied to said driving coils based on output signals of said position detector means;
- pulse-width modulator means which receives a torque command signal for controlling a generated torque of the brushless motor and generating an arbitrary frequency signal having a pulse width corresponding to the torque command signal;
- and
- PWM control means for controlling on/off operation of said upper drive means and said lower drive means based on output signals of said commutation switching means and an output signal of said pulse-width modulator means,
- wherein said PWM control means enables a synchronous rectification PWM operation to drive both said upper drive means and said lower drive means to perform a PWM operation, and said PWM control means does not perform the synchronous rectification PWM operation in a deceleration period in which a brake-wise current flows through said driving coils.
Dependencies are inferred from the claim text.