Five-level H-bridge converter and pre-charging method thereof

The invention discloses a five-level H-bridge converter, which is topologically of a five-level H-bridge single-phase output structure, adopts modular design, can form a multi-phase output system, andadopts an absorption loop to effectively reduce voltage spikes and oscillation on a specific switching device. By controlling the switching sequence of the switching devices, in the power-on processof the converter module, a load is connected to a DC bus to carry out segmented pre-charging on a capacitor bank in a circuit, and the current passing through the capacitor bank is prevented from being too large; and when the voltage of each segment of the capacitor bank is detected to reach a preset value, the pre-charging process is ended, the switching tube is controlled to cut off the connection between the load and the DC bus, and the converter enters a normal working mode. In comparison with a circuit topology used by the existing high-voltage five-level converter, the voltage spikes andthe oscillation caused by stray inductance existing in a high-voltage line on a specific switching device can be effectively reduced, capacitor banks in a circuit are effectively pre-charged in a segmented mode, and the voltage of each capacitor bank is controlled.