YASKAWA GA700 Technical Manual page 28

1.3 Features and Advantages of Control Methods
Open Loop Vector
Control
Method
Selection
Controlled
Motor
Zero Servo
No
Control
*2
Speed Search Yes
*2
Automatic
Energy-saving Yes
Control
*2
High Slip Braking
No
(HSB)
*2
Feed Forward
No
Control
*2
KEB Ride-Thru
Yes
Function
*2
Overexcitation
Yes
Deceleration
*2
Overvoltage
Suppression Yes
Function
*2 *3
*1 Select the drive capacity accordingly.
*2 Note these points when you use this function:
• When you can decouple the motor and machine for a test run, use Rotational Auto-Tuning. You must make adjustments to the
control in the range where there is no vibration in the machine after Rotational Auto-Tuning.
• For vector control, use a 1:1 drive to motor ratio. You cannot use vector control when more than one motor is connected to one
drive. Select a drive capacity so that the motor rated current is 50% to 100% of the drive rated current. If the carrier frequency is
too high, the drive rated current is derated.
• Motor loss increases during overexcitation braking and high-slip braking. Use a maximum braking frequency of 5% ED and a
maximum braking time of 90 seconds. After you start high-slip braking, you cannot restart the motor until it stops. Use
overexcitation braking to decelerate over a shorter time at a pre-determined speed.
• Acceleration and deceleration have priority over torque limits in Open Loop Vector Control during acceleration and deceleration
(soft start changes). The drive will not operate until the speed is at the minimum frequency or the reverse direction of motor
rotation when the motor speed decreases because of torque limits during constant speed control. Set L7-07 = 1 [Torque Limit
during Accel/Decel = Proportional & Integral control] to enable torque limits during acceleration/deceleration (for winding
applications).
*3 Do not use this function with hoist application.
28
Closed Loop Vector
Control Control
(OLV)
Induction Motor
Yes
-
Yes
No
Yes
Yes
Yes
Yes
YASKAWA ELECTRIC SIEP C710617 05F YASKAWA AC Drive GA700 Technical Manual
Advanced Open Loop
Vector Control
(CLV) (AOLV)
No
Yes
No
No
Yes
Yes
Yes
Yes
Notes
-
Locks servos without an external
position controller to prevent
movement caused by external
force.
Immediately estimates (or
detects) motor speed and
direction when coasting to a stop
to quickly start-up the drive
without stopping the motor.
Automatically adjusts the voltage
applied to motors to maximize
motor efficiency for all load
sizes.
Increases motor loss to let the
motor decelerate faster than usual
without a braking resistor. Motor
characteristics have an effect on
this function.
Compensates effects of the
system inertia to increase the
speed precision when the load
changes.
Quickly and safely stops the
motor during power loss and
automatically starts operation at
the previous speed when restores
power without coasting the
motor.
Sets the V/f higher than the
setting value during deceleration
to increase motor loss and
decrease deceleration time.
Adjusts speed during
regeneration to prevent
overvoltage.