11-1
CONTROL SYSTEM
SM HDDHED 2-A.1 GB
11 CONTROL SYSTEM
11.1 Electronic Control
11.1.1 Abbreviations
Abbreviation Definition
A/C Air Condition
BMS Building Management System
PWR System Power
CTT Compressor Top Temperature sensor
DCI DC Inverter
EEV Electronic Expansion Valve
HE Heating Element
HMI Human Machine Interface
HST Heat Sink Temperature sensor
Hz Hertz (1/sec) – electrical frequency
ICT Indoor Coil Temperature (RT2) sensor
IDU Indoor Unit
MCU Micro Controller Unit
OAT Outdoor Air Temperature sensor
OCT ODU Coil Temperature sensor
ODU Outdoor Unit
OFAN Outdoor Fan
PFC Power Factor Corrector
RAC Residential A/C
RAT Room Air Temperature sensor
RC Reverse Cycle (Heat Pump)
RCT Remote Control Temperature sensor
RGT Return Gas Temperature sensor
RPS Rounds per second (mechanical speed)
RV Reverse Valve
SB,STBY Stand By
SUCT Compressor Suction Temperature sensor
S/W Software
TBD To Be Defined
TMR Timer
11.1.2 System Operation Concept
The control function is divided between indoor and outdoor unit controllers. Outdoor unit is the system
‘Master’, requesting the indoor unit for cooling/heating capacity supply. The indoor unit is the system
‘Slave’ and it must supply the required capacity unless it enters into a protection mode avoiding it
from supplying the requested capacity.
Target frequency is transferred via indoor to outdoor communication, and the caculation is
based on room temperature and set point temperature.
11.1.3 Compressor Frequency Control
The Compressor Frequency Control is based on the PI scheme.
When starting the compressor, or when conditions are varied due to the change of the room
condition, the frequency must be initialized according to the ΔD value of the indoor unit and the Q
value of the indoor unit.
Q value: Indoor unit output determined from indoor unit capacity, air flow rate and other factors.
1. P control
Calculate ΔD value in each sampling time (20 seconds), and adjust the frequency according to its
difference from the frequency previously calculated.
2. I control
If the operating frequency is not change more than a certain fixed time, adjust the frequency up
and down according to the ΔD value.
Obtaining the fixed ΔD value
To Next Page
Loading...
Need help?
General
