Harmonic Analysis of Cascaded H-Bridge Inverters Under DC-Link Voltage Ripple
Year: 2026
Type: conference-paper
Abstract: In recent years, applications such as wideband digital power amplifiers, long-wave communication transmitters, and wideband grid impedance measurement have imposed increasingly stringent requirements on the frequency range and fidelity of power supplies. Cascaded H-bridge inverters have shown strong application potential in such scenarios owing to their high modularity, easy scalability of output voltage levels, and favorable harmonic performance. However, in practical systems, dc-side ripple is commonly present in each power unit. This non-ideal factor couples with the modulating wave and carrier during the pulse-width modulation process, thereby introducing subharmonics, interharmonics, and additional carrier sidebands into the output voltage. This paper investigates the output voltage spectral characteristics of cascaded H-bridge inverters under single-frequency dc-link ripple. First, a mathematical model of the dc-link voltage with a single sinusoidal ripple is established. Then, the output voltage spectral expressions of a single H-bridge cell and an N-cell cascaded H-bridge inverter are derived. The results show that dc-side ripple introduces two characteristic components around the fundamental frequency, located at$\boldsymbol{f}_{\mathbf{r}}-\boldsymbol{f}_{\mathbf{0}}$and$\boldsymbol{f}_{\mathbf{r}}+\boldsymbol{f}_{\mathbf{0}}$, and also generates additional sidebands around carrier harmonics with a frequency offset of$\boldsymbol{f}_{\mathbf{r}}$. Finally, the theoretical calculation results are compared with simulation results, verifying the correctness of the proposed spectral analysis.
Authors: Jiang Cao, Congrui Liu, Yan Li
Institutions: CRRC (China), Beijing Jiaotong University
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
OpenAlex ID: W7213395355