11-1
CONTROL SYSTEM
SM HDDHED 1-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
Δ
D
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
Δ
D
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
Δ
D
value.
Obtaining the fixed
Δ
D
value