Ac-ac converter and power supply system

A power supply system, comprising:

• an AC power source providing an input power and comprising two first wires;
• a load receiving a main output power and comprising three second wires;
• and
• an AC-AC converter connected between the AC power source and the load, converting the input power of the AC power source to the main output power of the load, and comprising:
• a first AC terminal configured to receive the input power and comprising a first sub terminal and a second sub terminal, wherein the first sub terminal and the second terminal are connected with the two first wires of the AC power source, respectively;
• a second AC terminal comprising a third sub terminal, a fourth sub terminal and a fifth sub terminal, wherein the third sub terminal is connected with the first sub terminal, the fifth sub terminal is connected with the second sub terminal, the third sub terminal, the fourth sub terminal and the fifth sub terminal are connected with the three second wires of the load, respectively, a first output power is formed between the third sub terminal and the fourth sub terminal, a second output power is formed between the fourth sub terminal and the fifth sub terminal, and the main output power is formed by the first output power and the second output power collaboratively;
• a first bridge arm connected between the first sub terminal and the second sub terminal and comprising a first switch assembly and a second switch assembly, wherein a connection node is formed between the first switch assembly and the second switch assembly, and the connection node is connected with the fourth sub terminal;
• a second bridge arm comprising at least one capacitor connected with the fourth sub terminal;
• and
• at least one inductor, wherein one end of the at least one inductor is connected with at least one of the first switch assembly and the second switch assembly, and the other end of the at least one inductor is connected with at least one of the third sub terminal, the fourth sub terminal and the fifth sub terminal.