Auxiliary power circuit, balance circuit, and power supply system

A conversion module, an input end of the conversion module comprising an even number of energy storage units coupled in series, and each energy storage unit comprising a first end and a second end,

• wherein the conversion module comprises an auxiliary power circuit, a power stage circuit and a control unit, the power stage circuit is coupled to the auxiliary power circuit, and the auxiliary power circuit comprising:
• an even number of primary-side circuits, and each primary-side circuit comprising:
• a first switch unit comprising a first end and a second end, and the first end of the first switch unit correspondingly coupled to the first end of one of the energy storage units,
• a second switch unit comprising a first end and a second end, and the first end of the second switch unit coupled to the second end of the first switch unit, and the second end of the second switch unit correspondingly coupled to the second end of one of the energy storage units, and
• a resonance tank coupled in parallel to the second switch unit, and
• a secondary-side circuit comprising:
• at least one induction unit coupled to the two resonance tanks of the two primary-side circuits, and
• a rectification circuit coupled to the at least one induction unit, and configured to rectify a power provided by the at least one induction unit into a DC power,
• wherein the conversion module further comprises:
• a second bus terminal coupled to the second end of the last series-connected energy storage unit, and
• wherein the conversion module selectively comprises a potential terminal, and the potential terminal is coupled to a node between two primary-side modules,
• wherein the control unit is configured to provide a control signal assembly to control the power stage circuit, so as to convert an input voltage received by the input end, and
• wherein the secondary-side circuit and the control unit are coupled to the potential terminal or the second bus terminal to use a potential of the potential terminal or a potential of the second bus terminal as a reference potential.