A Reduced Series/Parallel Module for Cascade Multilevel Static Compensators Supporting Sensorless Balancing

Li, Zhongxi; Motwani, Jayesh Kumar; Zeng, Zhiyong; Lukic, Srdjan; Peterchev, Angel V.; Goetz, Stefan M.

doi:10.1109/tie.2020.2965470

Cited by 29 publications

(6 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…PSC rotates states through all modules so that the modules get loaded similarly. Proper choice of the carrier sequence can furthermore exploit the opportunities of the parallel mode for charge balancing across modules as well as to reduce conduction loss [150,152]. Other modulation techniques are possible and described in the literature but are designed for the typically notably slower switching rates and output bandwidth (typically < 1,000 Hz) as common in power conversion applications and therefore often generate a substantially higher computational burden or lower-frequency distortion [153][154][155][156][157][158][159].…”

Section: + +mentioning

confidence: 99%

Transcranial Magnetic Stimulation Tech-nology with Freely Adjustable Pulse Shape and Sequence

Li¹,

Zhang²,

Peterchev³

et al. 2023

Preprint

View full text Add to dashboard Cite

The temporal shape of a pulse in transcranial magnetic stimulation (TMS) influences which neuron populations are activated preferentially as well as the strength and even direction of neuromodulation effects. Furthermore, various pulse shapes differ in their efﬁciency, coil heating, sensory perception, and clicking sound. However, the available TMS pulse shape repertoire is still very limited to a few biphasic, monophasic, and polyphasic pulses with sinusoidal or near-rectangular shapes. Monophasic pulses, though found to be more selective and stronger in neuromodulation, are generated inefﬁciently and therefore only available in simple low-frequency repetitive protocols. Despite a strong interest to exploit the temporal effects of TMS pulse shapes and pulse sequences, waveform control is relatively inflexible and only possible parametrically within certain limits. Previously proposed approaches for flexible pulse shape control, such as through power electronic inverters, have signiﬁcant limitations: The semiconductor switches can fail under the immense electrical stress associated with free pulse shaping, and most conventional power inverter topologies are incapable of generating smooth electric ﬁelds or existing pulse shapes. Leveraging intensive preliminary work on modular power electronics, we present a modular pulse synthesizer (MPS) technology that can, for the ﬁrst time, flexibly generate high-power TMS pulses (one-side peak ~ 4,000 V, ~ 8,000 A) with user-deﬁned electric ﬁeld shape as well as rapid sequences of pulses with high output quality. The circuit topology breaks the problem of simultaneous high power and switching speed into smaller, manageable portions, distributed across several identical modules. In consequence, MPS TMS can use semiconductor devices with voltage and current ratings lower than the overall pulse voltage and distribute the overall switching of several hundred kilohertz among multiple transistors. MPS TMS can synthesize practically any pulse shape, including conventional ones, with ﬁne quantization of the induced electric ﬁeld (≤ 17% granularity without modulation and ~300 kHz bandwidth). Moreover, the technology allows optional symmetric differential coil driving so that the average electric potential of the coil, in contrast to conventional TMS devices, stays constant to prevent capacitive artifacts in sensitive recording ampliﬁers, such as electroencephalography (EEG). MPS TMS can enable the optimization of stimulation paradigms for more sophisticated probing of brain function as well as stronger and more selective neuromodulation, further expanding the parameter space available to users.

show abstract

Section: + +mentioning

confidence: 99%

Transcranial Magnetic Stimulation Tech-nology with Freely Adjustable Pulse Shape and Sequence

Li¹,

Zhang²,

Peterchev³

et al. 2023

Preprint

View full text Add to dashboard Cite

show abstract

“…PSC rotates states through all modules so that the modules get loaded similarly. Proper choice of the carrier sequence can furthermore exploit the opportunities of the parallel mode for charge balancing across modules as well as to reduce conduction loss [147,149]. Other modulation techniques are possible and described in the literature but are designed for the typically notably slower switching rates and output bandwidth (typically <1000 Hz) as common in power conversion applications and therefore often generate a substantially higher computational burden or lower-frequency distortion [150][151][152][153][154][155][156].…”

Section: Control and Balancingmentioning

confidence: 99%

Modular pulse synthesizer for transcranial magnetic stimulation with fully adjustable pulse shape and sequence

Zhang

Peterchev

et al. 2022

J. Neural Eng.

Self Cite

View full text Add to dashboard Cite

The temporal shape of a pulse in transcranial magnetic stimulation (TMS) influences which neuron populations are activated preferentially as well as the strength and even direction of neuromodulation effects. Furthermore, various pulse shapes differ in their efﬁciency, coil heating, sensory perception, and clicking sound. However, the available TMS pulse shape repertoire is still very limited to a few biphasic, monophasic, and polyphasic pulses with sinusoidal or near-rectangular shapes. Monophasic pulses, though found to be more selective and stronger in neuromodulation, are generated inefﬁciently and therefore only available in simple low-frequency repetitive protocols. Despite a strong interest to exploit the temporal effects of TMS pulse shapes and pulse sequences, waveform control is relatively inflexible and only possible parametrically within certain limits. Previously proposed approaches for flexible pulse shape control, such as through power electronic inverters, have signiﬁcant limitations: Existing semiconductor switches can fail under the immense electrical stress associated with free pulse shaping, and most conventional power inverter topologies are incapable of generating smooth electric ﬁelds or existing pulse shapes. Leveraging intensive preliminary work on modular power electronics, we present a modular pulse synthesizer (MPS) technology that can, for the ﬁrst time, flexibly generate high-power TMS pulses (~ 4,000 V, ~ 8,000 A) with user-deﬁned electric ﬁeld shape as well as rapid sequences of pulses with high output quality. The circuit topology breaks the problem of simultaneous high power and switching speed into smaller, manageable portions, distributed across several identical modules. In consequence, MPS TMS can use semiconductor devices with voltage and current ratings lower than the overall pulse voltage and distribute the overall switching of several hundred kilohertz among multiple transistors. MPS TMS can synthesize practically any pulse shape, including conventional ones, with ﬁne quantization of the induced electric ﬁeld. Moreover, the technology allows optional symmetric differential coil driving so that the average electric potential of the coil, in contrast to conventional TMS devices, stays constant to prevent capacitive artifacts in sensitive recording ampliﬁers, such as electroencephalography (EEG). MPS TMS can enable the optimization of stimulation paradigms for more sophisticated probing of brain function as well as stronger and more selective neuromodulation, further expanding the parameter space available to users.

show abstract

“…To be specific, keep the additional switches (i.e., Sx5 and Sx6) on, the submodules that are not adjacent can also be connected in parallel, as long as their diagonal switches (e.g., Si1, Si4 and S(i+2)1, S(i+2)4) remain on. The ability of parallelization across submodules enables a further improvement of system efficiency [89], [94]. However, submodules alternate in this case.…”

Section: B Removal Of Redundant Active Switchesmentioning

confidence: 99%

“…Already with moderate switching, the inductors can be in the low microhenry range. Parasitic inductances of the module interconnections enhanced with ferrite cores have been demonstrated as effective [94].…”

Section: Interlinking Inductorsmentioning

confidence: 99%

A Review of Multilevel Converters With Parallel Connectivity

Fang

Blaabjerg

Liu

et al. 2021

IEEE Trans. Power Electron.

Self Cite

View full text Add to dashboard Cite

Cascaded-bridge converters (CBCs) and modular multilevel converters (MMCs) enjoy growing popularity mostly due to modularity and scalability. Conventionally, their submodules allow only serial and bypass operation so that the use of lowvoltage components for high-voltage output becomes possible. Dually, submodule parallelization adds switched-capacitor behavior to CBCs/MMCs and has witnessed an upward trend in recent years. Salient advantages of parallel operation comprise sensorless voltage balancing, capacitance saving, current sharing, and system efficiency optimization. To capture the advancement in the field, this article reviews state-of-the-art multilevel converters with parallel connectivity, covering various submodules, macro-level circuit topologies, implementation challenges and solutions, as well as control and optimization schemes. In particular, this article derives and classifies submodules as well as macro-level topologies according to basic H-bridge, asymmetrical half-bridge, and symmetrical half-bridge submodules. On top of that, this article introduces strategies for the simplification of submodules and creation of novel topologies yet maintaining parallel connectivity. We highlight the role of graph theory on creating new analytic and synthetic methodologies for multilevel converters. In addition, this article discloses the relationship between multilevel converters with parallel connectivity and switched capacitor converters.

show abstract

A Reduced Series/Parallel Module for Cascade Multilevel Static Compensators Supporting Sensorless Balancing

Cited by 29 publications

References 25 publications

Transcranial Magnetic Stimulation Tech-nology with Freely Adjustable Pulse Shape and Sequence

Transcranial Magnetic Stimulation Tech-nology with Freely Adjustable Pulse Shape and Sequence

Modular pulse synthesizer for transcranial magnetic stimulation with fully adjustable pulse shape and sequence

A Review of Multilevel Converters With Parallel Connectivity

Contact Info

Product

Resources

About