Patent ID: 11936294
Assignee: HUAWEI DIGITAL POWER TECHNOLOGIES CO., LTD.
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A three-level converter, comprising:
a high-voltage side unit;
a low-voltage side unit;
a flying capacitor;
a first switch;
a second switch;
a third switch;
a fourth switch; and
a control unit, wherein the first switch, the second switch, the third switch, and the fourth switch are connected in series and connected in parallel to the high-voltage side unit; a series connection point of the first switch and the second switch is connected to a series connection point of the third switch and the fourth switch by using the flying capacitor; the third switch and the fourth switch are connected in series and connected in parallel to the low-voltage side unit;
the control unit controls, when a voltage of the flying capacitor falls outside a target voltage range, the third switch and the fourth switch to be normally open in a first state, and controls, based on a voltage of the flying capacitor and a voltage of the low-voltage side unit, each of the first switch and the second switch to be turned on or off, so that the voltage of the flying capacitor falls within the target voltage range; or
the control unit further controls, when the voltage of the flying capacitor falls outside the target voltage range, the first switch and the second switch to be normally open in the first state, and controls, based on a voltage of the flying capacitor and a voltage of the low-voltage side unit, each of the third switch and the fourth switch to be turned on or off, so that the voltage of the flying capacitor falls within the target voltage range,
wherein the target voltage range is a voltage range that is greater than a difference between a half-intermediate direct current voltage and a preset deviation and is less than a sum of the half-intermediate direct current voltage and the preset deviation, and the half-intermediate direct current voltage is half of the voltage of the high-voltage side unit.