Power supply system for magnetic bearing and control method therefor

A power supply system for a magnetic bearing, comprising:

• a rectifying and filtering circuit, a power obtaining circuit, and a DC-DC power supply, wherein:
• the rectifying and filtering circuit is configured to rectify and filter an alternating current from an AC input power supply to obtain a first direct current with a first DC bus voltage, wherein the first direct current is configured to supply power to an electric motor controller of an electric motor to which the magnetic bearing belongs;
• the power obtaining circuit is configured to obtain a second direct current with a second DC bus voltage from the first direct current, wherein the second DC bus voltage is within an input voltage range allowed by the DC-DC power supply;
• and
• the DC-DC power supply is configured to convert the second direct current to a third direct current with a third DC bus voltage, wherein the third direct current is configured to supply power to a bearing controller of the magnetic bearing.