Product Features; Automated Functions - Danfoss VLT 380-500 V Design Manual

Product Features

5 Product Features

5.1 Automated Functions

These automated functions fall into 3 categories:
•
Turned on by default, but can be disabled by
programming.
•
Turned off by default, but can be enabled by
programming.
•
Always enabled.
5.1.1 Automatic Energy Optimization
Automatic energy optimization (AEO) is used in HVAC
applications. This feature directs the frequency converter to
monitor continuously the load on the motor and adjust
the output voltage to maximize efficiency. Under light
load, the voltage is reduced and the motor current is
minimized. The motor benefits from increased efficiency,
reduced heating, and quieter operation. There is no need
to select a V/Hz curve because the frequency converter
automatically adjusts motor voltage.
5.1.2 Automatic Switching Frequency
Modulation
The frequency converter generates short electrical pulses
to form an AC wave pattern. The carrier frequency is the
rate of these pulses. A low carrier frequency (slow pulsing
Power
kW (hp)
250 (350)
315 (450)
355 (500)
400 (550)
450 (600)
500 (650)
560 (750)
630 (900)
710 (1000)
800 (1200)
Table 5.1 Carrier Frequency Operational Ranges for 380–500 V
MG37N102
Design Guide
Switching frequency
Hz
3000
2000
2000
2000
2000
2000
2000
2000
2000
2000
Danfoss A/S © 6/2016 All rights reserved.
rate) causes noise in the motor, making a higher carrier
frequency preferable. A high carrier frequency, however,
generates heat in the frequency converter which can limit
the amount of current available to the motor. The use of
insulated gate bipolar transistors (IGBT) means high-speed
switching.
Automatic switching frequency modulation regulates these
conditions automatically to provide the highest carrier
frequency without overheating the frequency converter. By
providing a regulated high carrier frequency, it quiets
motor operating noise at slow speeds, when audible noise
control is critical, and produces full output power to the
motor when the demand requires.
5.1.3 Automatic Derating for High Carrier
Frequency
The frequency converter is designed for continuous and
full load operation between the carrier frequencies
between the minimum and maximum frequencies shown
in Table 5.1. If the carrier frequency is higher than the
maximum frequency, the output current of the frequency
converter is derated automatically.
Minimum Maximum
Hz Hz
2000 8000
1500 6000
1500 6000
1500 6000
1500 6000
1500 6000
1500 6000
1500 6000
1500 6000
1500 6000
5
Factory Setting
Hz
3000
2000
2000
2000
2000
2000
2000
2000
2000
2000
15
5