Yaskawa Matrix Converter - Manual (Page 373)

MxC Control Methods
10-
3
10
* 1. The variable speed control range. For continuous operation, the motor's temperature rise must be considered.
* 2. The speed deviation in relation to the maximum speed with a rated load and when the load is stable. For Open Loop Vector Control, the motor temperature must
be 25 °C ± 10 °C.
* 3. The speed response guidelines indicating the extent of the motor's actual speed gain in proportion to the speed reference, which changes in a sinusoidal wave
form, within a range where motor torque does not become saturated.
* 4. A guideline for the motor torque that can be generated when started at a low speed and its output frequency (rotations) at that time.
* 5. This function limits the maximum motor torque to protect the machine and the load.
* 6. This function directly controls the amount of torque being generated at the motor and its rotation direction, e.g., to control force.
* 7. This function controls the amount of motor slip that occurs to prevent mechanical shock, when replacing a torque motor, etc.
* 8. This function performs simple positioning control (servo lock), without using an external positioning control device.
* 9. This function instantaneously estimates or detects the speed and rotation direction of a coasting motor, and quickly starts it without subjecting it to shock.
* 10.This function enables proportional gain in relation to changes in the speed reference, even for low rigidity (corresponds to the servo's model gain control).
„ Application Function Precautions
Observe the following precautions when using the application functions.
• Perform Rotational Auto-Tuning during a test run whenever it is possible to separate the motor and
machine. To achieve the characteristics of Open Loop Vector Control described in Table 10.1, the control
must be adjusted within a range that the machine will not vibrate after Rotational Auto-Tuning has been
performed.
• With vector control, the motor and MxC must be connected 1:1. Vector control is not possible when multi-
ple motors are connected to a single MxC. Select an MxC capacity so the rated motor current is 75% of the
rated MxC current.
• For estimated speed searching, the motor and MxC must be connected 1:1. The speed search must be per-
formed at a frequency of 120 Hz or less and with a motor with the same number of frames as or one frame
less than the MxC capacity.
• Feed Forward Control is a function that improves the proportional gain of the motor speed in relation to
the change in the speed reference. Adjust the response to interference loads using the speed controller
(ASR) parameters.
• The torque limit function will not operate during acceleration or deceleration (during soft start transition)
when using a control method such as Open Loop Vector Control. Even if the motor speed drops due to
torque limiting while set to a fixed speed, the speed will not fall below the minimum frequency and the
motor will not slip into reverse rotation. These conditions also apply to other application functions.
Appli-
cation
Func-
tions
Speed
Estimation
(Detection)
Instantaneous
Speed
Search
*9
Yes (speed and rotation direc-
tion estimation)
Yes (speed and rotation direc-
tion estimation)
Yes (speed and rotation direc-
tion detection)
Feed Forward
Control
*10
No No Yes
Table 10.1 Overview of Control Methods and Features
Control Method V/f Control Open Loop Vector Control Flux Vector Control