Texas Instruments Three Phase BLDC & PMSM Motor Kit with DRV8301 and InstaSPIN-enabled Piccolo TMS320F28069M MCU DRV8301 DRV8301-69M-KIT 데이터 시트
제품 코드
DRV8301-69M-KIT
(
)
RMS
PEAK
LRA
V
V
1
800
s f
=
-
m
PEAK
5.44V
V
ODClamp[7 : 0]
255
=
AVG
PEAK
(DriveTime - 300 s)
V
V
DriveTime
IDissTime
BlankingTime
m
=
+
+
PEAK
5.44 V
V
ODClamp[7 : 0]
255
=
OD
5.6 V
V
ODClamp[7 : 0]
255
=
SLOS825B – DECEMBER 2012 – REVISED JANUARY 2014
PROGRAMMING THE OVERDRIVE CLAMP VOLTAGE
During closed loop operation, the actuator feedback lets the output voltage go above the rated voltage during the
automatic overdrive and automatic braking periods. The ODClamp[7:0] value (Register 0x17) sets a clamp so
that the automatic overdrive is bounded. This also serves as the full scale reference voltage for open loop
operation. The ODClamp[7:0] value always represents the peak voltage that is allowed, regardless of the mode.
Note that if the supply voltage (VDD) is less than the overdrive clamp voltage, the output driver will not be able to
reach the clamp voltage value because the output voltage cannot exceed the supply voltage. Also note that if the
rated voltage exceeds the overdrive clamp voltage, the overdrive clamp voltage will supercede.
automatic overdrive and automatic braking periods. The ODClamp[7:0] value (Register 0x17) sets a clamp so
that the automatic overdrive is bounded. This also serves as the full scale reference voltage for open loop
operation. The ODClamp[7:0] value always represents the peak voltage that is allowed, regardless of the mode.
Note that if the supply voltage (VDD) is less than the overdrive clamp voltage, the output driver will not be able to
reach the clamp voltage value because the output voltage cannot exceed the supply voltage. Also note that if the
rated voltage exceeds the overdrive clamp voltage, the overdrive clamp voltage will supercede.
LRA Mode (Closed Loop) and ERM Mode (Open Loop)
is the peak voltage allowed during all modes of operation.
(4)
ERM Mode (Closed Loop)
Although
Although
gives the peak voltage for the overdrive clamp, it is desirable in ERM mode to know the
average voltage obtained when clamped. The closed loop mode periodically samples the actuator back EMF.
During this time, the driver is not applying voltage to the actuator. To achieve equivalent performance between
the open loop and closed loop modes, it is useful to relate the peak clamp voltage to the average voltage. This
relationship is given by
During this time, the driver is not applying voltage to the actuator. To achieve equivalent performance between
the open loop and closed loop modes, it is useful to relate the peak clamp voltage to the average voltage. This
relationship is given by
(5)
(6)
Default Values:
DriveTime = 4.8 ms
IDissTime = BlankingTime = 75 µs
V
DriveTime = 4.8 ms
IDissTime = BlankingTime = 75 µs
V
AVG
= 0.91 V
PEAK
(with default values)
LRA Mode (Open Loop)
The ODClamp[7:0] value sets the peak value when open loop LRA mode is used. Please note that LRA Open
Loop Mode can only be used with PWM inputs.
The ODClamp[7:0] value sets the peak value when open loop LRA mode is used. Please note that LRA Open
Loop Mode can only be used with PWM inputs.
(7)
The V
RMS
value can be calculated from the peak value using the following equation:
(8)
38
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