Omron SYSDRIVE 3G3FV, User Manual, Page: 19 / 400

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Selection of Modes for Vector Control and V/f Control
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The 3G3FV has the following four control modes.
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Open-loop vector control (without PG*) [Factory default]
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Flux vector control (with PG)
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V/f control (without PG)
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V/f control (with PG)
*PG stands for “pulse generator” (encoder).
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Vector control is a method for removing interferences 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’s primary current and its phases. This al-
lows smooth rotation and high torque, along with accurate speed and torque control, at very low
speeds.
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Vector control can be replaced from the conventional V/f control system. If the motor parameter re-
quired for vector control is unknown, it can be set automatically with the auto-tuning function.
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The respective control modes are effective for the following applications:
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Open-loop vector control (without PG): General variable speed drive
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Flux vector control (with PG): Simple servo-drive, high-precision speed control, torque control
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V/f control (without PG): Conventional Inverter control mode. Used for multiple drives.
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V/f control (with PG): Simple speed feedback control
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The control characteristics for each mode are shown in the following table.
Vector control V/f control
Without PG With PG Without PG With PG
Speed control range 1:100 1:1,000 1:40 1:40
Speed control precision
±
0.2%
±
0.02%
±
2 to 3%
±
0.03%
Starting torque 150% at 1 Hz 150% at 0 Hz 150% at 3 Hz
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Auto-tuning Function
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This function is valid with vector control.
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The motor parameters are set automatically just by entering the motor’s rating plate value. This fea-
ture allows flux vector control to operate accurately with virtually any normal AC induction motor
regardless of the supplier.
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Torque Control
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This function is valid with flux vector control (with PG).
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Torque is controlled by taking multi-function analog input signals as torque references.
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Switching is possible between torque control and speed control.
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V/f Pattern Settings
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This function is valid for V/f control.
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Select a V/f pattern according to the application from among the 15 preset V/f patterns.
Introduction
Chapter 1