Apparatus and method for controlling the operating frequency of compressor in air conditioning apparatus

A method for controlling the operation frequency of a compressor in an air conditioning apparatus, comprising the steps of:

• a) allowing an interrupt;
• b) receiving operation data in a predetermined period and performing a PID algorithm on the operation data to determine an operation frequency after allowing the interrupt;
• c) operating the compressor according to the determined operation frequency;
• d) receiving low order harmonic frequencies of two phases of a three phase AC applied to the compressor as a line voltage and determining whether the line voltage is below a first set value, between the first set value and a second set value or above the second set value;
• and
• e) operating the compressor in a previous operation state if the line voltage is below the first set value, operating the compressor in an operation state one step lower than the previous speed if the line voltage is between the first set value and the second set value, or operating the compressor in a lowest operation state if the line voltage is above the second set value.

An apparatus for controlling an operation frequency of a compressor comprising:

• means for detecting low order harmonic frequencies of two phases of a three phase output as a line voltage;
• means for amplifying the detected line voltage of the two phases;
• means for determining a state of the amplified line voltage of the two phases;
• and
• means for operating the compressor based on the state of the amplified line voltage.

A method for controlling an operation frequency of a compressor comprising the steps of:

• detecting low order harmonic frequencies of two phases of a three phase output as a line voltage;
• amplifying the detected line voltage of the two phases;
• determining a state of the amplified line voltage of the two phases;
• and
• operating the compressor based on the state of the amplified line voltage.