Control Structures; Control Principle; Control Structure Open Loop; Pm/Ec+ Motor Control - Danfoss FC 101 Design Manual

Product Overview

2.7 Control Structures

2.7.1 Control Principle

1-00 Configuration Mode can be selected if open or closed loop is to be used.

2.7.2 Control Structure Open Loop

Reference
handling
Remote
reference
Auto mode
Hand mode
Local
reference
scaled to
Hz
LCP Hand on,
off and auto
on keys
Illustration 2.17 Open Loop Structure
In the configuration shown in Illustration 2.17, 1-00 Configu-
ration Mode is set to [0] Open loop. The resulting reference
from the reference handling system or the local reference
is received and fed through the ramp limitation and speed
limitation before being sent to the motor control. The
output from the motor control is then limited by the
maximum frequency limit.

2.7.3 PM/EC+ Motor Control

The Danfoss EC+ concept provides the possibitily for using
high efficient PM motors (permanent magnet motors) in
IEC standard frame size operated by Danfoss frequency
converters.
The commissioning procedure is comparable to the
existing one for asynchronous (induction) motors by
utilising the Danfoss VVC plus PM control strategy.
Customer advantages:
•
Free choice of motor technology (permanent
magnet or induction motor)
•
Installation and operation as know on induction
motors
•
Manufacturer independent when selecting system
components (e.g. motors)
•
Best system efficiency by selecting best
components
•
Possible retrofit of existing installations
®
VLT HVAC Basic Drive FC 101 Design Guide
P 4-14
Motor speed
high limit [Hz]
Remote
Reference
Local
P 4-12
Motor speed
low limit [Hz]
MG18C502 - Rev. 2013-09-06
100%
P 3-4* Ramp 1
P 3-5* Ramp 2
0%
Ramp
100%
-100%
•
Power range: 45 kW (200 V), 0.37-90 kW (400 V),
90 kW (600 V) for induction motors and 0.37-22
kW (400 V) for PM motors.
Current limitations for PM motors:
•
Currently only supported up to 22 kW
•
Currently limited to non salient type PM motors
•
LC filters not supported together with PM motors
•
Over Voltage Control algorithm is not supported
with PM motors
•
Kinetic backup algorithm is not supported with
PM motors
•
Support reduced AMA of the stator resistance Rs
in the system only
•
No stall detection
•
No ETR function
2
To motor
control
P 4-10
Motor speed
direction
25
2