Frequency Control; How To Determine Frequency; For Heat Pump Model - Daikin Altherma EKHBH Series Service Manual

Outdoor Unit Functional Concept
3.3

Frequency Control

1
Outline
2
3
4
5
How to determine
frequency
For heat pump
model
2–14
Frequency will be determined according to the difference between water and set temperature.
The function is explained as follows.

How to determine frequency.

Frequency command from a hydro-box (the difference between the water temperature and the
temperature set by the remote controller).
Frequency command from a hydro-box.
Frequency initial setting.
PI control.
Frequency changes by PI control < repeats when frequency becomes lower
Command frequency X repeats when frequency becomes lower
Command frequency
Initial frequency
PI control
Defrost control
The compressor's frequency will finally be determined by taking the following steps.
Determine command frequency
Command frequency will be determined in the following order of priority.
Limiting frequency by drooping function
Input current, discharge pipes, low Hz high pressure limit, peak cutting, freeze prevention, fin
thermistor temperature.
Limiting defrost control time
Forced cooling
Indoor frequency command
Determine upper limit frequency
Set a minimum value as an upper limit frequency among the frequency upper limits of the following
functions:
Compressor protection, input current, discharge pipes, Low Hz high pressure, peak cutting, freeze
prevention, defrost.
Determine lower limit frequency
Set a maximum value as an lower limit frequency among the frequency lower limits of the following
functions:
Four way valve operating compensation, pressure difference upkeep.
Determine prohibited frequency
There is a certain prohibited frequency such as a power supply frequency.
Drooping function
Input current control, etc.
Upper limit frequency
FMAX
Compressor protection function
Limit frequency Skip control
Lower limit Lower limit function
frequency Four-way valve operating compensation, etc.
ESIE06-03
Upper limit function
Target frequency
Part 2 – Functional Description