Voltage converting device and method of controlling the voltage converting device

A method of controlling a voltage converting device, wherein the voltage converting device comprises:

• a first power supply, having a first positive terminal and a first negative terminal;
• a first bridge circuit, having a first switching transistor and a second switching transistor, coupled to the first positive terminal;
• a second bridge circuit, having a third switching transistor and a fourth switching transistor, coupled between the first bridge circuit and the first negative terminal;
• a second power supply, having a second positive terminal and a second negative terminal;
• a third bridge circuit, having a fifth switching transistor and a sixth switching transistor, coupled to the second positive terminal;
• and
• a fourth bridge circuit, having a seventh switching transistor and an eight switching transistor, coupled between the third bridge circuit and the second negative terminal;
• and
• an inductive circuit, coupled between the first bridge circuit and the second bridge circuit;
• and
• the method comprises:
• receiving a request for discharging current to the second power supply from the first power supply;
• detecting a first voltage level of the first power supply and a second voltage level of the second power supply;
• when the first voltage level is smaller than the second voltage level:
• controlling the voltage converting device to operate in a first cycle having a first time interval T1 and a second time interval T2;
• during the second time interval T2, detecting if a current of the inductive circuit crosses a zero current;
• and
• when the current crosses the zero current in the second time interval T2, controlling the voltage converting device to operate in a second cycle having a third time interval T3 and a fourth time interval T4 or a third cycle having a seventh time interval T7 and an eighth interval T8 after the second time interval T2;
• when the first voltage level is higher than the second voltage level:
• controlling the voltage converting device to operate in a fourth cycle having a fifth time interval T5 and a sixth time interval T6;
• during the sixth time interval T6, detecting if the current of the inductive circuit crosses the zero current;
• and
• when the current crosses the zero current in the sixth time interval T6, controlling the voltage converting device to operate in a fifth cycle having the third time interval T3 and the fourth time interval T4 or a sixth cycle having the seventh time interval T7 and the eighth interval T8, or a seventh cycle having the third time interval T3 and the fourth time interval T4 after the sixth time interval T6.