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

Claim 10:
11. A control method of a three-level converter, applicable to a control unit in the three-level converter; the 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, and a fourth switch, 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, and the method comprises:
when a voltage of the flying capacitor falls outside a target voltage range, controlling the third switch and the fourth switch to be normally open in a first state, and controlling, 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
when the voltage of the flying capacitor falls outside the target voltage range, controlling the first switch and the second switch to be normally open in the first state, and controlling, 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 target voltage range, and
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.