Toshiba RAS-M14EAV-E, RAS-M18EACV-E Operation Description, Outline of Air Conditioner Control, 34

• 4-way valve control

• P.M.V. control

• Operation control of outdoor fan motor

9. OPERATION DESCRIPTION

9-1. Outline of Air Conditioner Control

This air conditioner is a capacity-variable type air conditioner, which uses DC motor for the indoor fan motor and the outdoor fan motor. And the capacity- proportional control compressor which can change the motor speed in the range from 9 to 120 rps is mounted. The DC motor drive circuit is mounted to the indoor unit. The compressor and the inverter to control fan motor are mounted to the outdoor unit. The entire air conditioner is mainly controlled by the indoor unit controller.

The indoor unit controller drives the indoor fan motor based upon command sent from the remote control- ler, and transfers the operation command to the outdoor unit controller.

The outdoor unit controller receives operation command from the indoor unit side, and controls the outdoor fan and the pulse motor valve. (P.M.V) Besides, detecting revolution position of the com- pressor motor, the outdoor unit controller controls speed of the compressor motor by controlling output voltage of the inverter and switching timing of the supply power (current transfer timing) so that motors drive according to the operation command.

And then, the outdoor unit controller transfers reversely the operating status information of the outdoor unit to control the indoor unit controller.

As the compressor adopts four-pole brushless DC motor, the frequency of the supply power from inverter to compressor is two-times cycles of the actual number of revolution.

(1)Role of indoor unit controller

The indoor unit controller judges the operation commands from the remote controller and assumes the following functions.

•Judgment of suction air temperature of the indoor heat exchanger by using the indoor temp. sensor. (TA sensor)

•Detection of inverter input current and current release operation

•Over-current detection and prevention operation to IGBT module (Compressor stop function)

•Compressor and outdoor fan stop function when serial signal is off (when the serial signal does not reach the board assembly of outdoor control by trouble of the signal system)

•Transferring of operation information (Serial signal) from outdoor unit controller to indoor unit controller

•Detection of outdoor temperature and opera- tion revolution control

•Defrost control in heating operation (Temp. measurement by outdoor heat exchanger and control for four-way valve and outdoor fan)

(3)Contents of operation command signal (Serial signal) from indoor unit controller to outdoor unit controller

The following three types of signals are sent from the indoor unit controller.

•Operation mode set on the remote control

•Compressor revolution command signal defined by indoor temperature and set temperature (Correction along with variation of room temperature and correction of indoor heat exchanger temperature are added.)

•Temperature of indoor heat exchanger

•For these signals ([Operation mode] and [Compressor revolution] indoor heat exchanger temperature), the outdoor unit controller monitors the input current to the inverter, and performs the followed operation within the range that current does not exceed the allow- able value.

(4)Contents of operation command signal (Serial signal) from outdoor unit controller to indoor unit controller

• Judgment of the indoor heat exchanger	The following signals are sent from the outdoor
temperature by using heat exchanger sensor	unit controller.
(TC sensor) (Prevent-freezing control, etc.)	• The current operation mode
• Louver motor control	• The current compressor revolution
• Indoor fan motor operation control	• Outdoor temperature
• LED (Light Emitting Diode) display control
	• Existence of protective circuit operation
• Transferring of operation command signal
	For transferring of these signals, the indoor
(Serial signal) to the outdoor unit
	unit controller monitors the contents of signals,
• Reception of information of operation status
	and judges existence of trouble occurrence.
(Serial signal including outside temp. data) to
	Contents of judgment are described below.
the outdoor unit and judgment/display of error
	• Whether distinction of the current operation
• Air purifier operation control
(2) Role of outdoor unit controller	status meets to the operation command signal
	• Whether protective circuit operates
Receiving the operation command signal (Serial
	When no signal is received from the outdoor
signal) from the indoor unit controller, the out-
door unit performs its role.	unit controller, it is assumed as a trouble.

• Compressor operation control  Operations followed to  judgment of serial signal  from indoor side.

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