DRV10983_15 Datasheet, PDF (20/57 Pages) Texas Instruments – DRV10983 12- to 24-V, Three-Phase, Sensorless BLDC Motor Driver

DRV10983
SLVSCP6B – JULY 2014 – REVISED FEBRUARY 2015
www.ti.com
If the UW comparator output is lagging the UV comparator by 60°, the motor is spinning forward. If the UW
comparator output is leading the UV comparator by 60°, the motor is spinning in reverse.
The motor speed is determined by measuring the time between two rising edges of either of the comparators.
If neither of the comparator outputs toggle for a given amount of time, the condition is defined as stationary. The
amount of time can be programmed by setting the register bits ISDThr[1:0].
9.4.3.2 Motor Resynchronization
The resynchronize function works when the ISD function is enabled and determines that the initial state of the
motor is spinning in the forward direction. The speed and position information measured during ISD are used to
initialize the drive state of the DRV10983, which can transition directly into the closed loop running state without
needing to stop the motor.
9.4.3.3 Reverse Drive
The ISD function measures the initial speed and the initial position; the DRV10983 reverse drive function acts to
reverse accelerate the motor through zero speed and to continue accelerating until the closed loop threshold is
reached (see Figure 12). If the reverse speed is greater than the threshold configured in RvsDrThr[1:0], then the
DRV10983 waits until the motor coasts to a speed that is less than the threshold before driving the motor to
reverse accelerate.
Speed
Open loop
Closed loop
Op2ClsThr
Time
Coasting
Reverse Drive
RevDrThr
Figure 12. Reverse Drive Function
Reverse drive is suitable for applications where the load condition is light at low speed and relatively constant
and where the reverse speed is low (that is, a fan motor with little friction). For other load conditions, the motor
brake function provides a method for helping force a motor which is spinning in the reverse direction to stop
spinning before a normal start-up sequence.
9.4.3.4 Motor Brake
The motor brake function can be used to stop the spinning motor before attempting to start the motor. The brake
is applied by turning on all three of the low-side driver FETs.
If the motor is spinning at a speed that is greater than the braking threshold (configured by BrkDoneThr[2:0]),
then dynamic braking acts to stop the spinning (whether forward or reverse). After the motor is stopped (that is,
the motor speed is less than the BrkDoneThr[2:0]), the motor position is unknown. To proceed with restarting in
the correct direction, the IPD or Align and Go algorithm needs to be implemented. The motor start sequence is
the same as it would be for a motor starting in the stationary condition.
The motor brake function can be disabled. The motor skips the brake state and attempts to spin the motor as if it
were stationary. If this happens while the motor is spinning in either direction, the start-up sequence may not be
successful.
20
Submit Documentation Feedback
Product Folder Links: DRV10983
Copyright © 2014–2015, Texas Instruments Incorporated