Main Functions; Frequency Principle - Daikin FTXS09HVJU Service Manual

SiUS04-904

1. Main Functions

1.1

Frequency Principle

The compressor is frequency-controlled during normal operation. The target frequency is set by the
Main Control
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
Function and Control
Phase
1 The supplied AC power source is converted into a DC power source.
The DC power source is reconverted into a three-phase AC power source with variable
2
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)
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

Main Functions

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