A Transformerless Hybrid Modular Multilevel DC–DC Converter With DC Fault Ride-Through Capability

Zhang, Fei; Li, Wei; Joós, G.

doi:10.1109/tie.2018.2869355

Cited by 30 publications

(21 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…13. The designed sizing of SM energy storing element is computed according to the modulation index that matches the highest loading as shown in (59) that are calculated by differentiating (28) or (36) with respect to modulation index and equating it to zero.…”

Section: Second Control Method: V/i Control For Zero Reactive Powermentioning

confidence: 99%

“…In addition, a transformer-less hybrid modular multilevel DC-DC converter has been proposed [35], where another version was proposed in [36] with DC fault blocking capability but they cannot be used for connecting LCC-HVDC and VSC-HVDC networks. On the other hand, the DC modular choppers, which utilize lower number of SMs as introduced in [37], employ capacitive or inductive energy storing elements but these converters exhibit AC circulating current due to the hard switching of SMs, which increase conduction losses [38].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A New Hybrid Dual Active Bridge Modular Multilevel Based DC–DC Converter for HVDC Networks

et al. 2021

View full text Add to dashboard Cite

Multi-terminal high voltage DC transmission currently represents a leading technology in longdistance power transmission systems. Among the main technical challenges facing such technology, DC fault isolation, permitting different grounding schemes, providing interoperability, and high DC voltage stepping between different HVDC networks, and allowing high-speed power reversal without power interruption especially when connecting the pre-existing voltage source converters (VSC) and line commutated converters (LCC)-based HVDC networks. This paper introduces a new modular multilevel converter (MMC) based front-to-front DC-DC converter to interconnect two different types (LCC/VSC) of HVDC networks. The proposed topology comprises a voltage source MMC (VS-MMC) and a current source MMC (CS-MMC), while both are coupled via an AC link including the isolating transformer. The proposed topology can successfully provide an uninterruptible bi-directional power flow, high DC voltage stepping with a DC fault blocking capability, and low number of semiconductors due to the usage of only half-bridge SMs. The system design is provided with a detailed mathematical analysis. Furthermore, two active power control methodologies are proposed and compared. The first control technique is simpler and entails lower passive elements, while the second technique ensures a zero reactive power over the full range of active power flow. Furthermore, Losses analysis and comparison are provided between the two proposed control techniques. Finally, Control-Hardware-in-the-Loop (CHiL) test validation is employed to confirm the validity of the proposed system under healthy as well as different fault scenarios.INDEX TERMS Modular multilevel converter, DC-DC power converters, HVDC, Power control, Bidirectional power flow, Control-Hardware-in-the-Loop (CHiL).

show abstract

Section: Second Control Method: V/i Control For Zero Reactive Powermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A New Hybrid Dual Active Bridge Modular Multilevel Based DC–DC Converter for HVDC Networks

et al. 2021

View full text Add to dashboard Cite

show abstract

“…As for low (1<ratio≤1.5) and medium (1.5<ratio≤5) voltage ratio connections, non-isolated topologies are more attractive. Compared with the FTF-MMCs, modular multilevel DC/DC converter (MMDC) topologies [18]- [24] have been proposed which have only one conversion stage and do not need the AC link transformer. As shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

“…As a result, the current stress and power losses are both significant and a large reactor is required at the DC output to filter the injected AC voltages. To avoid using the reactor, additional SM strings have been utilized in [23] and [24] to actively attenuate the injected AC voltages, but this is at the expense of higher semiconductor count and power losses.…”

Section: Introductionmentioning

confidence: 99%

A Monopolar Symmetrical Hybrid Cascaded DC/DC Converter for HVDC Interconnections

Zhang

Cheng

et al. 2021

IEEE Trans. Power Electron.

View full text Add to dashboard Cite

With the rapid development of voltage source converter (VSC) based high voltage direct current (HVDC) transmission, it is an irresistible trend that HVDC grid will come into being. High-voltage and high-power DC/DC converters will serve as DC transformers in HVDC grid to interconnect DC lines with different voltage ratings. This paper proposes a monopolar symmetrical DC/DC converter which is composed of cascaded half-bridge sub-modules (SMs) and series-connected IGBTs. This hybrid topology features low capital costs, high efficiency, small footprint, and bidirectional power transfer capability. Operation principle, parameter design, and the control strategies of this topology are introduced. A 480MW, ±500kV/±160kV monopolar symmetrical DC/DC converter is simulated to verify its performance and evaluate the efficiency. In addition, a downscaled prototype rated at 2.4kW, ±300V/±100V has been built and tested. Experimental results further validate the effectiveness of the proposed DC/DC converter.

show abstract

“…The MLI‐based SAPF can be implemented by using neutral point diode clamped (NPC) MLI [30], flying capacitor MLI [31], cascaded H‐bridge (CHB) [32–36] and modular converter [37–39]. The drawback of the NPC topology is neutral point fluctuation, which can be mitigated by using advanced control circuits [30].…”

Section: Introductionmentioning

confidence: 99%

Eight‐switch CHB‐based three‐level three‐phase shunt active power filter

Muneer

Bhattacharya

2020

IET power electron.

View full text Add to dashboard Cite

A Transformerless Hybrid Modular Multilevel DC–DC Converter With DC Fault Ride-Through Capability

Cited by 30 publications

References 36 publications

A New Hybrid Dual Active Bridge Modular Multilevel Based DC–DC Converter for HVDC Networks

A New Hybrid Dual Active Bridge Modular Multilevel Based DC–DC Converter for HVDC Networks

A Monopolar Symmetrical Hybrid Cascaded DC/DC Converter for HVDC Interconnections

Eight‐switch CHB‐based three‐level three‐phase shunt active power filter

Contact Info

Product

Resources

About