Danfoss iC2-Micro Series - Power Losses and Efficiency; Frequency Converter

3.3.2 Power Losses and Efficiency
Elements causing power loss in the system are shown in Figure 3.
Mains and
cabling
Feeding
section
Auxiliaries
Basic Drive
Module
(BDM)
Transmission
Load
machine
e30bi586.11
Driven Equipment
Complete Drive Module (CDM)
Extended Product
Motor System
Power Drive System (PDS)
Often named as VSD (Variable Speed Drive)
Motor Starter
(Contactor, Softstarter,....)
Figure 3: Drive System Design
The following components can cause losses in the system:
l Mains supply cable.
l External input filter (if installed).
l Frequency converter, including built-in filters.
l External output filter (if installed).
l Motor cable.
l Motor.
The frequency converter itself only provides a part of the total losses of the system.
Mains supply cable
Losses in the mains supply cable are mainly caused by the ohmic resistance of the cable. To keep the losses at a minimum, the cable
length should be kept short and sized properly to the rated current.
External input filter
Externally added input filters add to the losses in the system. Line reactors used to balance the load between multiple drives in a load
sharing setup typically have a voltage drop of approximately 1%, causing up to 1% losses at full load.
Dedicated harmonic filters typically have losses of 2–5%.
Frequency converter
The loss of the frequency converter is load-dependent. Specific classifications and power loss data are shown on the product label, and
details can be seen in MyDrive® ecoSmart™.
External output filter
Externally connected output filters add losses to the system:
l Sine-wave filters suppress the PWM pattern of the output frequency, resulting in a sine wave output. The resulting loss is load
dependent and can be up to 1–1.5% of maximum power. Using a sine-wave filter in installations with long motor cables can result in
a better overall efficiency.
l dU/dt filters limit the voltage rise time of the PWM pattern. As a result, the filters introduce loss in the system – Loss is load
dependent and can be up to 0.5-1% of maximum power.
18 | Danfoss A/S © 2024.08 AJ402315027937en-000401 / 130R1239
Design Guide | iC2-Micro Frequency Converters iC2-Micro Frequency Converters