SiUS04-924
1. Main Functions
1.1
Frequency Principle
Main Control
The compressor is frequency-controlled during normal operation. The target frequency is set by the
following 2 parameters coming from the operating indoor unit:
Parameters
The load condition of the operating indoor unit
The difference between the room temperature and the set temperature
Additional
The target frequency is adapted by additional parameters in the following cases:
Frequency restrictions
Control
Initial settings
Parameters
Forced cooling operation
Inverter Principle
To regulate the capacity, a frequency control is needed. The inverter makes it possible to vary the
rotation speed of the compressor. The following table explains the conversion principle:
Drawing of
The following drawing shows a schematic view of the inverter principle:
Inverter
Inverter Features
The inverter provides the following features:
The regulating capacity can be changed according to the changes in the outdoor air
Quick heating and quick cooling.
12
Phase
1
The supplied AC power source is converted into a DC power source.
2
The DC power source is reconverted into a three-phase AC power source with variable
frequency.
When the frequency increases, the rotation speed of the compressor increases resulting in
increased refrigerant circulation. This leads to a higher amount of heat exchange per unit.
When the frequency decreases, the rotation speed of the compressor decreases resulting
in decreased refrigerant circulation. This leads to a lower amount of heat exchange per unit.
Amount of heat
exchanged air (large)
Amount of heat
exchanged air (small)
temperature and cooling / heating load.
Description
Refrigerant circulation rate (high)
high f
low f
50 Hz
freq=
freq=variable
constant
60 Hz
Refrigerant circulation rate (low)
high speed
Amount of heat
exchanged air (large)
Amount of heat
exchanged air (small)
low speed
capacity=
variable
Function and Control
Main Functions
(R2812)