Introduction
1.1.2 Outline of Control Methods
1 - 4
1.1.2 Outline of Control Methods
The VS-616G5 uses four control methods.
D
Open-loop vector control (factory setting)
D
Flux vector control
D
V/f control without PG
D
V/f control with PG feedback
PG stands for pulse generator (encoder).
Vector control is a method for removing interference with magnetic flux and torque, and controlling torque
according to references.
Current vector control independently controls magnetic flux current and torque current by simultaneously
controlling the motor primary current and phases. This ensures smooth rotation, high torque, and accurate
speed/torque control at low speeds.
Vector control can be replaced by the conventional V/f control system. If the motor constants required for
vector control are not known, the motor constants can be automatically set with autotuning.
The control methods are effective for the following applications:
D
Open-loop vector control:
General variable-speed drive.
D
Flux vector control:
Simple servodrive, high-precision speed control/torque control.
D
V/f control without PG:
Conventional Inverter control mode. Used for multi-drive operation
(connecting multiple motors to one Inverter).
D
V/f control with PG feedback: Simple speed feedback control. (For applications with the PG
connected to the machine shaft rather than the motor shaft.)
The control characteristics for each mode are shown in
Table 1.2
.
Table
1.2
Control Method Characteristics
Characteristic
Vector Control
V/f Control
Open-loop
Flux Vector
Without PG
With PG feedback
Speed Control
Range
1
:
100
1
:
1000
1
:
40
1
:
40
Speed Control
Precision
±
0.2
%
±
0.02
%
±
2 to 3
%
±
0.03
%
Initial Drive
150% at 1 Hz
150% at 0 r/min
150% at 3 Hz
1.1.3
Functions
J
Autotuning
Autotuning is effective for vector control. It solves problems in applicable motor restrictions and difficult
constant settings. The motor constants are automatically set by entering a value from the motor’s rating
nameplate.
Autotuning allows flux vector control to operate accurately with virtually any normal AC induction motor,
regardless of the supplier.
Always autotune the motor separately before operating using vector control. Refer to
5.2.5 Autotuning
and
6.4.3 Autotuning
for details.
J
Torque Control
Torque control is effective for flux vector control with PG. Torque is controlled by taking multi-function
analog input signals as torque references. Torque control accuracy is
±
5%. Switching is possible between
torque control and speed control.
J
V/f Pattern Settings
V/f pattern settings are effective for V/f control. Select a V/f pattern according to the application from
among the 15 preset V/f patterns. Custom V/f patterns can also be set.
J
Frequency References
The following five types of frequency references can be used to control the output frequency of the Invert-
er.
D
Numeric input from the Digital Operator
D
Voltage input within a range from 0 to 10 V
D
Voltage input within a range from 0 to
±
10 V (with negative voltages, rotation is in the opposite direc-
tion from the run command.)
1
Summary of Contents for VARISPEED-616G5
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