Table of Contents
Advertisement
4-12 Electronic Expansion Valve
The circulation volume of the refrigerant is controlled by a pulse type electronic control valve.
When the power is switched ON, the opening degree of the electronic control valve is controlled between 90
and 480 steps after setting the initial step at the time when the thermostat is ON.
Contents and Order of control
Discharge gas temperature control
Outdoor unit coil temperature control
Freeze prevention control
Refrigerant flow distribution control
Discharge gas target temperature
control (Fuzzy control)
*
Even though the operation is performed every 30 seconds, the control of discharge gas temperature, high
load prevention, outdoor unit coil temperature and freeze prevention activates when it occurs.
(1) Refrigerant flow distribution control
At the control of flexible combination (a plural number of indoor units are set), the opening degree of the
electronic control valve is controlled by the indoor unit coil temperature.
Cooling: indoor unit coil E2 temperature (located at the middle of coil)
Heating: indoor unit coil E1 temperature (located at the outlet of coil)
(2) Fuzzy control (optimal refrigerant flow rate control)
By outputting the fuzzy estimation result corresponding to the fuzzy input variables (the indoor unit coil
temp., the deviation between the actual discharge gas temp. and the target discharge gas temperature
calculated from the outdoor unit coil temperature and the change thereof), the electronic refrigerant valve is
controlled so that the unit can perform its maximum ability in accordance with the indoor and outdoor
temperature conditions at the operation.
4-13 Voltage Detection Control
When the power voltage falls below 160 V (voltage between N phase and each phase) or rises above 260 V,
the "P2" alarm is issued to protect the compressor and electrical components.
Cooling
Start
Heating
Start
Discharge gas temperature control
High load prevention control
Heating start up control
Refrigerant flow distribution control
Discharge gas target temperature
control (Fuzzy control)
*
23
*
Advertisement
Table of Contents
