Balancing control scheme of DC‑link capacitor voltages for five‑level hybrid T‑type inverters without auxiliary circuit

Min-Seok Kim; Dong-Choon Lee

Balancing control scheme of DC‑link capacitor voltages for five‑level hybrid T‑type inverters without auxiliary circuit

Min-Seok Kim

Dong-Choon Lee

Vol. 23, No. 3, pp. 467-477, Mar. 2023

10.1007/s43236-023-00592-5

Auxiliary balancing circuit

Carrier-overlapped pulse-width modulation

Capacitor voltage balancing

Levelshifted pulse-width modulation

Multilevel inverter

Medium voltage application

Abstract

In this paper, a balancing control scheme of DC-link capacitor voltages for five-level hybrid T-type (5L-HT) inverters is proposed, where existing auxiliary balancing circuit is eliminated. The 5L-HT inverter has a significant advantage of the reduced number of devices compared with other five-level inverter topologies. However, this inverter requires an auxiliary balancing circuit, which is used to rectify the voltage imbalance at the DC-link capacitors, and thus negates the competitiveness of this topology in terms of device count and converter volume. To eliminate the auxiliary circuit, a carrier-overlapped PWM (COPWM) is applied in place of the conventional level-shifted PWM (LSPWM) to control the neutral-point currents, where the duty ratios of switches are adjusted by PI controllers. As a result, although the THD of the output voltage is rather increased, the cost and volume are saved by 27% and 52%, respectively, for a 1-MW/6.6-kV system. The effectiveness of the proposed balancing control method for the 5L-HT inverter has been verified through the simulation and experimental results for the prototype hardware.

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Cite this article

[IEEE Style]

M. Kim and D. Lee, "Balancing control scheme of DC‑link capacitor voltages for five‑level hybrid T‑type inverters without auxiliary circuit," Journal of Power Electronics, vol. 23, no. 3, pp. 467-477, 2023. DOI: 10.1007/s43236-023-00592-5.

[ACM Style]

Min-Seok Kim and Dong-Choon Lee. 2023. Balancing control scheme of DC‑link capacitor voltages for five‑level hybrid T‑type inverters without auxiliary circuit. Journal of Power Electronics, 23, 3, (2023), 467-477. DOI: 10.1007/s43236-023-00592-5.