Motor variable frequency driving system and multi-split central air conditioner

A motor variable frequency driving system, comprising:

• a three-phase alternating-current input;
• a rectification module connected to the three-phase alternating-current input and used for converting the three-phase alternating-current input into a direct current output;
• a thin-film capacitor arranged between output ends of the direct current output;
• an inverter, with an input end of the inverter connected to the output end of the direct current output and an output end of the inverter connected to a three-phase alternating current motor;
• a vector control module connected to the inverter and used for generating a control instruction for controlling the inverter;
• an A/D sampling module used for collecting direct current bus voltages of two ends of the thin-film capacitor;
• and
• a steady state processing module connected to the A/D sampling module and used for carrying out steady state processing on the direct current bus voltage and outputting a compensation parameter to the vector control module, wherein
• the vector control module further comprises:
• an SVPWM unit used for outputting a control instruction to the inverter;
• and
• the steady state processing module further comprises:
• a high-frequency component processing unit, with one end of the high-frequency component processing unit connected to the A/D sampling module and the other end of the high-frequency component processing unit connected to the SVPWM unit, used for correcting the control instruction output by the SVPWM unit, and wherein the high-frequency component processing unit is configured to extract and reprocess a high-frequency component of the direct current bus voltage.