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IGBT parameters_
| Vdc | 50 V |
| Irms | 2.16 A |
| VT0 | 0.8 V |
| VD0 | 1.1 V |
| T | 20 ms |
| ton | 700 ns |
| toff | 450 ns |
Comparison of proposed RSSS MLI with recently developed MLI topologies between 2022 and 2025_
| Ref. | Topology | No. of levels | Switch count | DC sources | Control/modulation | THD (%) | Efficiency (%) | Remarks |
|---|---|---|---|---|---|---|---|---|
| Goel et al. (2022) | Single DC-source 13-level MLI | 13 | 10 | 1 | Fundamental switching | ∼8–10 | ∼95 | Reduced device count but limited scalability |
| Kubendran et al. (2022) | Reduced-switch cascaded MLI | 9–17 | 12 | Multiple | Nearest level control | ∼9–12 | ∼94 | Suitable for EV applications but requires multiple sources |
| Jena et al. (2024) | Transformer-less switched-capacitor MLI | 9 | 12 | 1 | PWM-based control | 16.48 | ∼94 | Self-balancing capacitors but higher THD without filtering |
| Saravanan et al. (2024) | Reduced-device 31-level inverter | 31 | 12 | Multiple | SPWM | <8 | ∼95 | Higher number of levels but increased circuit complexity |
| Mohanty et al. (2025) | Reduced-switch asymmetrical MLI | 9–13 | 10–12 | Multiple | PSO-optimised controller | ∼7–9 | ∼95 | Designed for DC microgrid applications |
| Awadelseed et al. (2026) | Switched-capacitor ANPC inverter | 9 | 10–12 | 1 | Optimised modulation | ∼5–7 | 96.9 | High efficiency but uses capacitor balancing circuitry |
| Proposed RSSS MLI | This work | 9 | 8 | 1 | GA-SHE | ≈10.86 | ≈95 | Reduced switch count with GA-based harmonic elimination |
Variation of switching angles with modulation index_
| Modulation index | θ1 | θ2 | θ3 | θ4 |
|---|---|---|---|---|
| 1.000 | 8.4389 | 19.2314 | 36.1245 | 57.3176 |
| 0.950 | 9.1926 | 19.5797 | 36.4326 | 58.9095 |
| 0.925 | 9.9500 | 20.0029 | 37.2343 | 59.1851 |
| 0.900 | 10.4054 | 20.4507 | 38.0021 | 59.4559 |
| 0.850 | 11.4501 | 21.2809 | 38.9241 | 60.0872 |
| 0.825 | 12.0383 | 21.5013 | 39.5321 | 60.4146 |
| 0.800 | 13.4202 | 22.5694 | 39.8726 | 61.2269 |
| 0.750 | 14.3501 | 22.8389 | 40.2547 | 62.0705 |
| 0.725 | 14.8955 | 23.4178 | 40.9432 | 62.0796 |
| 0.700 | 15.2552 | 24.3045 | 41.3125 | 62.7213 |
| 0.650 | 16.1434 | 24.9320 | 41.7658 | 63.2394 |
| 0.625 | 16.6702 | 25.6596 | 42.4325 | 64.1026 |
| 0.600 | 17.0195 | 26.4618 | 42.8654 | 64.6620 |
Variations of THD with modulation index_
| Modulation index | Output voltage THD (%) | Output current THD (%) |
|---|---|---|
| 1 | 9.64 | 3.08 |
| 0.950 | 10.86 | 3.32 |
| 0.925 | 11.53 | 4.09 |
| 0.900 | 12.77 | 4.33 |
| 0.850 | 12.48 | 5.20 |
| 0.825 | 12.42 | 4.61 |
| 0.800 | 12.25 | 4.15 |
| 0.750 | 12.92 | 3.94 |
| 0.725 | 13.77 | 4.44 |
| 0.700 | 14.61 | 5.02 |
| 0.650 | 17.68 | 5.88 |
| 0.625 | 19.57 | 5.92 |
| 0.600 | 18.36 | 6.53 |
Comparison of proposed RSSS MLI with recently developed MLI topologies_
| MLI topologies | Nsw | NDC | TSV |
|---|---|---|---|
| CHB MLI Najjar et al. (2016) |
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| MLI1 Oskuee et al. (2015) |
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| MLI2 Babaei et al. (2014a) |
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| MLI3 Lee et al. (2018) |
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| MLI4 Hsieh et al. (2016) |
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| MLI5 Jayabalan et al. (2017) |
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| MLI6 Babaei et al. (2014b) |
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| Proposed RSSS MLI |
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Switching sequence of proposed RSSS MLI_
| State | S1 | S2 | … | Sn | T1 | T2 | T3 | T4 | Vdc |
|---|---|---|---|---|---|---|---|---|---|
| 1 | 0 | 0 | … | 0 | 0/1 | 1/0 | 0/1 | 1/0 | 0 |
| 2 | 1 | 0 | … | 0 | 1 | 0 | 1 | 0 | +1 |
| 3 | 1 | 0 | … | 0 | 0 | 1 | 0 | 1 | −1 |
| 4 | 0 | 1 | … | 0 | 1 | 0 | 1 | 0 | +2 |
| 5 | 0 | 1 | … | 0 | 0 | 1 | 0 | 1 | −2 |
| 6 | 0 | 0 | … | 0 | 1 | 0 | 1 | 0 | +3 |
| 7 | 0 | 0 | … | 0 | 0 | 1 | 0 | 1 | −3 |
| ⋮ | ⋮ | ⋮ | … | ⋮ | ⋮ | ⋮ | ⋮ | ⋮ | ⋮ |
| ⋮ | ⋮ | ⋮ | … | ⋮ | ⋮ | ⋮ | ⋮ | ⋮ | ⋮ |
| Nlevel − 1 | 0 | 0 | … | 1 | 1 | 1 | 0 | 0 | +n |
| Nlevel | 0 | 0 | … | 1 | 0 | 0 | 1 | 1 | −n |
Comparison of performance of proposed RSSS MLI and recently developed MLI topologies_
| Topology | Output levels | Power switches | DC sources | Diodes/capacitors | Voltage gain | TSV | Control technique | THD (%) | Remarks |
|---|---|---|---|---|---|---|---|---|---|
| CHB MLI Najjar et al. (2016) | 9 | 16 | 4 | 0 | High | High | PWM/SHE | 8–12 | Modular but high switch count |
| MLI1 Oskuee et al. (2015) | 9 | 12 | 4 | 2 | Medium | Medium | PWM | 9–13 | Moderate complexity |
| MLI2 Babaei et al. (2014) | 9 | 10 | 3 | 2 | Medium | Medium | PWM | 10–14 | Multiple DC sources |
| MLI3 Lee et al. (2018) | 9 | 12 | 4 | 2 | Medium | High | SPWM | 9–12 | Higher voltage stress |
| MLI4 Hsieh et al. (2016) | 9 | 10 | 4 | 2 | Medium | High | PWM | 10–13 | Increased circuit complexity |
| MLI5 Jayabalan et al. (2017) | 9 | 10 | 3 | 2 | Medium | High | SPWM | 9–12 | Higher TSV |
| MLI6 Babaei et al. (2014) | 9 | 10 | 3 | 0 | Medium | Medium | PWM | 9–13 | Reduced device count |
| Reduced Switched-Capacitor MLI Hosseinzadeh et al. (2022) | 9 | 10–12 | Multiple | Capacitors | High | Medium | PWM | <10 | Requires capacitor voltage balancing |
| Reduced-switch cascaded MLI Kubendran et al. (2022) | 9–17 | 12 | Multiple | 0 | Medium | Medium | Nearest Level Control | 9–12 | Requires multiple sources |
| Generalised Multisource Inverter Hosseinzadeh et al. (2024) | 9–13 | 12 | Multiple | Capacitors | High | Medium | Model predictive control | <8 | High control complexity |
| Multi-Source MLI Espinosa et al. (2025) | 9 | 10–12 | Multiple | Capacitors | High | Medium | PWM | <10 | Flexible multi-source operation |
| Proposed RSSS MLI | 9 | 8 | Single source | None | High | Low | GA-SHE | 10.86 | Reduced switch count and simplified control |