Flying capacitor three-level converter and flying capacitor three-level buck-boost converter

A flying capacitor three-level buck-boost converter, comprising one or more circuit units, wherein each circuit unit of the one or more circuit units comprises a first flying capacitor unit, a second flying capacitor unit, an input capacitor, an output capacitor, an inductor, a first bridge arm and a second bridge arm;

• the input capacitor is electrically connected in parallel with the first bridge arm, and the output capacitor is electrically connected in parallel with the second bridge arm;
• the first bridge arm comprises a first switch, a second switch, a third switch, and a fourth switch, wherein the first switch, the second switch, the third switch and the fourth switch are sequentially connected in series;
• the second bridge arm comprises a fifth switch, a sixth switch, a seventh switch, and an eighth switch, wherein the fifth switch, the sixth switch, the seventh switch and the eighth switch are sequentially connected in series;
• the first flying capacitor unit comprises a first capacitor and a second capacitor, wherein the first capacitor and the second capacitor are electrically connected in parallel and are electrically connected in parallel with a first series branch, and the first series branch comprises the second switch and the third switch in the first bridge arm;
• the input capacitor, the first switch, the first capacitor and the fourth switch form a first switching loop;
• the second switch, the third switch and the second capacitor form a second switching loop;
• the second flying capacitor unit comprises a third capacitor and a fourth capacitor, wherein the third capacitor and the fourth capacitor are electrically connected in parallel and are electrically connected in parallel with a second series branch, and the second series branch comprises the sixth switch and the seventh switch in the second bridge arm;
• the output capacitor, the fifth switch, the third capacitor and the eighth switch form a third switching loop;
• the sixth switch, the seventh switch and the fourth capacitor form a fourth switching loop;
• and
• the inductor is coupled between a junction node of the second switch and the third switch in the first bridge arm and a junction node of the sixth switch and the seventh switch in the second bridge arm;
• wherein the converter further comprises a first heat dissipation unit and a second heat dissipation unit;
• wherein the first switches and the fourth switches in all the first switching loops are arranged on the first heat dissipation unit;
• wherein the second switches and the third switches in all the second switching loops are arranged on the second heat dissipation unit;
• wherein the fifth switches and the eighth switches in all the third switching loops are arranged on the first heat dissipation unit;
• and
• wherein the sixth switches and the seventh switches in all the fourth switching loops are arranged on the second heat dissipation unit.

A flying capacitor multilevel converter, comprising:

• N circuit units, wherein each circuit unit of the N circuit units comprises m flying capacitor units, an input capacitor and a bridge arm, wherein Nis a positive integer greater than 1, and m is a positive integer greater than or equal to 2;
• wherein the bridge arm comprises 2×(m+1) switches, and the 2×(m+1) switches are sequentially connected in series;
• wherein each of the m flying capacitor units comprises a first capacitor and a second capacitor, and the first capacitor is electrically connected in parallel with the second capacitor;
• wherein a first flying capacitor unit of the m flying capacitor units is electrically connected in parallel at both ends of a series branch which is defined by a second switch to the (2m+1)th switch, and the input capacitor, a first switch, the first capacitor of the first flying capacitor unit and the 2×(m+1)th switch form a first switching loop;
• wherein the second capacitor of the first flying capacitor unit, the second switch, the first capacitor of a second flying capacitor unit of the m flying capacitor units and the (2m+1)th switch form a second switching loop;
• wherein a kth flying capacitor unit of the m flying capacitor units is electrically connected in parallel at both ends of a series branch which is defined by the (k+1)th switch to the (2m+2−k)th switch, wherein k is a natural number from 2 to m;
• wherein the second capacitor of the (k−1)th flying capacitor unit of the m flying capacitor units, a kth switch, the first capacitor of the kth flying capacitor unit and the (2m+3−k)th switch form a kth switching loop;
• wherein the second capacitor of a mth flying capacitor unit of the m flying capacitor units, a (m+1)th switch and a (m+2)th switch form a (m+1)th switching loop;
• wherein the converter further comprises (m+1) heat dissipation units;
• wherein the first switches and the (2×(m+1))th switches in all the first switching loops are arranged on the first heat dissipation unit;
• wherein the second switches and the (2m+1)th switches in all the second switching loops are arranged on the second heat dissipation unit;
• wherein the kth switches and the (2m+3−k)th switches in all the kth switching loops are arranged on the kth heat dissipation unit;
• wherein the (m+1)th switches and the (m+2)th switches in all the (m+1)th switching loops are arranged on the (m+1)th heat dissipation unit.