Omron SYSDRIVE MX2 SERIES, User Manual

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6 Vector Control and Applied Functions
Multi-function Compact Inverter 3G3MX2-V1 User’s Manual (I585-E1)
6-8
PM Motor Mode
6
6-
8-1 PM Motor
and PM Motor
Contr
ol
6-8 PM Motor Mode
The 3G3MX2-V1 Series Inverter provides the PM motor mode.
This mode enables the Inverter to control a synchronous motor (PM motor) which is more efficient than
an induction motor (IM motor).
This section describes the PM motor mode.
A PM motor (abbreviation for “Permanent Magnet motor”) is a motor that uses permanent magnets for
the motor rotor.
Generally, it is also called a synchronous motor. Compared with induction motors that are used conven-
tionally for the inverter, PM motors allow no current flow on the rotor side, which results in highly effi-
cient operation due to reduced loss.
In terms of the internal construction, there are various types of PM motors: IPM motors (interior perma-
nent magnet type), SPM motors (surface permanent magnet type), and so on.
PM motors have the control characteristics as shown below.
When using the PM motor mode of the 3G3MX2-V1 Series Inverter, understand the following charac-
teristics before selecting the inverter type and function settings.
• The applied AC power must be synchronized with the rotor permanent magnets.
Although the motor allows a large current to flow, it cannot output a sufficient torque if the AC power
is not synchronized.
• The permanent magnets used for the rotor are subject to demagnetization if a large current flows in
the PM motor.
Once rotor is demagnetized, the motor cannot output a sufficient torque and must be replaced.
The 3G3MX2-V1 Series Inverter uses sensorless control to realize PM motor control.
This means that the inverter cannot output a large starting torque.
PM motor control is suitable for applications with reduced torque characteristics (which do not require
torque at low speeds) such as fans and pumps.
However, it cannot be used for applications with constant torque characteristics such as general trans-
fer equipment and elevating axes (which require a torque exceeding the rated torque also at low
speeds).
To keep the PM motor in a synchronized state, use the inverter with a starting torque of 50% of the
motor rated torque or lower.
Follow the steps below to use PM motor control:
(1) Switch to the PM motor mode. (P. 6-57)
(2) Perform offline auto-tuning for PM motor parameters. (P. 6-57)
(3) Set PM motor parameters. (P. 6-61)
Refer to this section if offline auto-tuning fails.
(4) Adjust the PM motor mode settings. (P. 6-63)
6-8-1 PM Motor and PM Motor Control
PM Motor
PM Motor Control