This air conditioner has variable capacity that uses DC motors for the internal fan motors and for the external fan. It also uses a compressor with proportional capacity control that can modify the engine speed within the range of 15 to 90 rps. The DC motor drive circuit is mounted on the indoor unit. The compressor and converter of the fan control motor are mounted on the outdoor unit. The air conditioner is entirely controlled by the indoor unit control.
The control of the indoor unit starts the motor of the indoor fan controlled by the remote control and transfers the operating command to the control of the outdoor unit.
The control of the external unit receives the operating command of the internal unit and controls the external fan and the pulse modulating valve. In addition, when detecting the rotation position of the compressor motor, the control of the external unit controls the speed of the compressor motor, monitoring the output voltage of the inverter and the switching time of the power supply (current transfer time). so that the motors operate according to the operating command. So, unit control
indoor transfers inversely information about the operating conditions of the outdoor unit and monitors the control of the indoor unit.
As the compressor has a brushless four-pole DC motor, the frequency of the electrical supply from the inverter to the compressor has twice the number of revolutions cycles.
