Toshiba RAS-13YAV-E, RAS-13YKV-E Operation Description, Outline of Air Conditioner Control

8. OPERATION DESCRIPTION

8-1. 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 13 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 modulating valve. 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.

• Temperature setting of the indoor heat ex- changer by using heat exchanger sensor (Prevent-freezing control)

• Louver motor control

• Indoor fan motor operation control

• LED display control

• Transferring of operation command signal (Serial signal) to the outdoor unit

• Reception of information of operation status (Serial signal including outside temp. data) to the outdoor unit and judgment/display of error

(2) Role of outdoor unit controller

Receiving the operation command signal (Serial signal) from the indoor controller, the outdoor unit performs its role.

•	Compressor operation		Operations followed
	control
•	Operation control of		to judgment of serial
	outdoor fan motor		signal from indoor
			side.
•	P.M.V. control

•Detection of inverter input current and current release operation

•Over-current detection and prevention opera- tion to transistor 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 to indoor unit

•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)

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