Texas Instruments Corporation

Seil Oh

John Kevin Rote

Zachery Scott Buckley

Juergen Luebbe

David R Street

Tuan Van Tran

Quang Dieu An

Brian Lee Schmidt

Jasraj R Dalvi

A system includes a timer to determine a time interval between successive commutation state changes of a brushless direct current (BLDC) motor. A speed calculator computes a speed of the BLDC motor based on the time interval. A threshold calculator determines a threshold based on the computed speed, the threshold specifying a calculation of back electromotive force (BEMF) and mutual inductance of the BLDC motor at a next state change of the BLDC motor. A state change trigger commands the next state change based on a measured voltage associated with a floating phase of the BLDC motor relative to the threshold.

Converged motor drive control for brushless dc motor

A method includes: outputting high side driver gate signals to a plurality of high side driver devices and outputting low side driver gate signals to a plurality of low side driver devices configured to control current supplied to a motor having coils coupled to receive the current at a plurality of phase nodes; at a time approximately prior to an expected zero crossing of a voltage at a selected one of the plurality of phase nodes, disabling the high side driver gate signal and the low side driver gate signal; measuring a back electromotive force (BEMF) voltage and observing a zero crossing time; estimating a next zero crossing time; prior to the next zero crossing time, disabling the high side driver gate signal and the low side driver gate signal and observing the selected one of the phase nodes to form a first sample; and following the next zero crossing time, observing a second voltage at the selected one of the phase nodes to form a second sample.

Methods and apparatus for automatic lead angle adjustment using fly-back voltage for brushless DC control

A circuit includes a driver circuit having a high side switch device and a low side switch device coupled to a load voltage node and a motor winding output. A controller operates the high side switch device and the low side switch device. The controller operates in a normal mode to supply current to the motor winding output for driving a motor winding when an external power supply is available to supply the load voltage node. In response to detecting a loss of the external power supply, the controller operates the high side switch device and the low side switch device in a boost mode to utilize a back electromotive force (BEMF) voltage from the motor winding to supply current to the load voltage node.

Configuration, frequency registers generating power from motor in supply-loss event

Systems and methods for increasing Pulse Width Modulation (PWM) resolution for digitally controlled motor control applications are described. For example, in some embodiments, a method may include receiving a clock signal having a given period; identifying a target duty cycle; calculating a comparison point based upon the given period and the target duty cycle; generating a PWM signal based upon the clock signal using the comparison point; and varying the comparison point to increase a resolution of an effective duty cycle of the PWM signal.

Increasing PWM resolution for digitally controlled motor control applications

To achieve peak acoustic and power performance, the coil or applied current should be in phase or substantially aligned with the back electromotive force (back-EMF) voltage. However, there are generally phase differences between the applied current and back-EMF voltage that are induced by the impedance of the brushless DC motor (which can vary based on conditions, such as temperature and motor speed). Traditionally, compensation for these phase differences was provided manually and on an as-needed basis. Here, however, a system and method are provided that automatically perform a commutation advance by incrementally adjusting a drive signal over successive commutation cycles when the applied current and back-EMF voltage are misaligned.

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Plano, TX, United States of America

Seil Oh