Analysis of a Synergetically Controlled Two-Stage Three-Phase DC/AC Buck-Boost Converter

Antivachis, Michael; Anderson, Jon Azurza; Bortis, Dominik; Kolar, Johann W.

doi:10.24295/cpsstpea.2020.00004

Cited by 51 publications

(19 citation statements)

References 26 publications

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“…In reality, a hardware prototype achieves 40-50% lower power density, due to the unaccounted volume of the air between the components and of the control electronics. The detailed design process of a DB-VSI can be found in (Antivachis et al, 2020a), while the parameters of the selected benchmark designs are given in Table 3.…”

Section: Multiobjective Optimizationmentioning

confidence: 99%

Novel High-Speed Turbo Compressor With Integrated Inverter for Fuel Cell Air Supply

Antivachis

Dietz²,

Zwyssig³

et al. 2021

Front. Mech. Eng.

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Fuel cell technology is continuously gaining ground in E-mobility applications. Fuel cells require a constant supply of pressurized air, for which high-speed turbo compressors with air bearings are an optimal choice to reduce size, guarantee oil-free operation required for the lifetime of the fuel cell, and increase efficiency. However, the inverter driving the electric motor of the turbo compressor does not scale down with increasing speed; therefore, other technology advances are required to achieve an overall compressor system with low weight. New power electronic topologies (double-bridge voltage sources inverter), cutting edge power semiconductor technology (gallium nitride), and multiobjective optimization techniques allow reducing the inverter size, increasing inverter efficiency, and improving the output current quality and in return lowering the losses in the electric motor. This enables the electrical, mechanical, and thermal integration of the inverter into the compressor housing of very high-speed and compact turbo compressors, thereby reducing the size and weight of the overall compressor system by a factor of two. Furthermore, a turbo compressor with an integrated inverter reduces complexity and cost for operators with savings in casing, cables, coolant piping, and connectors and reduces EMI noise by shielding the high-frequency motor currents with one housing. Beside its main application for fuel cell air supply, the advantages gained by an integrated inverter can also be used in other boosting and air handling applications such as advanced air and exhaust handling in combustion engines. The proposed integration concept is verified with a 280,000 rpm, 1 kW turbo compressor, targeted for the Balance of Plant (BoP) of a 5–15 kW fuel cell. The experimental results show that the temperature limits on the power electronics parts can be kept below the limit of 90 °C up to a coolant temperature of 55 °C, and beside the advantage of lower cabling effort, the efficiency of the compressor system (turbo compressor and integrated inverter) is increased by 5.5% compared to a turbo compressor without an integrated inverter.

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Section: Multiobjective Optimizationmentioning

confidence: 99%

Novel High-Speed Turbo Compressor With Integrated Inverter for Fuel Cell Air Supply

Antivachis

Dietz²,

Zwyssig³

et al. 2021

Front. Mech. Eng.

Self Cite

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“…3) and translating them into a pulse pattern in the time domain. It can be visualized that the 2-L inverter switching functions (s a , s b and s c ) are alternately clamped either to 0 or 1 for two-thirds of the fundamental period, as in the 1/3 Modulation [20]. This behavior derives from avoiding the 2-L inverter zero states, which allows to switch only one inverter bridge-leg in each sector.…”

Section: Output Voltage Formationmentioning

confidence: 99%

“…To achieve 3-sinusoidal (in local average) output voltages, the 3-L SM operates such that the local average of v hl follows the 3rectified line-to-line output voltage fundamentals. In other words, in each sector, the 3-L SM sets the desired voltage between the two clamped phases, leaving to the third inverter bridge-leg the regulation of the two remaining 3-line-toline output voltages [20].…”

Section: Output Voltage Formationmentioning

confidence: 99%

Analysis and performance evaluation of a three-phase sparse neutral point clamped converter for industrial variable speed drives

et al. 2021

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This paper analyzes the operation and characterizes the performance of a three-phase three-level (3-L) Sparse Neutral Point Clamped converter (SNPCC) for industrial variable speed drives (VSDs). The operating principle of the SNPCC, which advantageously employs a lower number of power transistors than a conventional 3-L inverter, is described in detail, focusing on the AC-side differential-mode and common-mode voltage formation and on the DC-side mid-point current generation processes. The degrees of freedom in the SNPCC modulation scheme are defined and several switching sequences are investigated. Afterwards, the stresses on the active and passive components (e.g. semiconductor losses, machine phase current ripple, DC-link capacitor RMS current, etc.) are calculated by analytical and/or numerical means, enabling a straightforward performance comparison among the identified switching sequences. The most suited modulation strategy for VSD applications is then selected and a chip area sizing procedure, aimed at minimizing the total semiconductor chip size, is applied to a 800V 7.5kW three-phase system. The performance limits of the designed SNPCC are evaluated and finally compared to the ones of conventional 2-L and 3-L solutions, highlighting the promising cost/performance trade-off of the analyzed topology.

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“…The EMT model implements an iterative procedure to take the implications of elevated temperatures on core and copper losses into account, i.e., the losses and the temperatures are computed in a subsequent manner until both, losses and temperatures, reach convergence. The employed EMT modeling approach has been experimentally verified in several converter designs, e.g., [36], [37]. For the analysis, and unless otherwise specified, the following considerations apply:…”

Section: Semi-numerical Analysismentioning

confidence: 99%

Minimum Loss Operation and Optimal Design of High-Frequency Inductors for Defined Core and Litz Wire

Papamanolis

Guillod

Krismer

et al. 2020

IEEE Open J. Power Electron.

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This paper studies the loss-optimal design of a power inductor employed in a 2 kW, 400 V input DC-DC converter. The design of an inductor is subject to a large number of design parameters and the implications of the different design parameters on the losses are often not clearly traceable in a full optimization, e.g., different current ripple amplitudes can lead to designs with similar losses, as larger ripple amplitudes lead to increased AC core and winding losses but lower DC losses in the winding due to lower inductance values and/or numbers of turns. In an effort to achieve a comprehensible description of the implications of the key design parameters (switching frequency, current ripple, number of turns) on the losses, the remaining parameters, e.g., core (E55/28/21 N87) and type of conductor (litz wire), are considered to be given. In a first step, the investigation is based on a simplified analytical model, which is refined in a step-by-step manner, e.g., to consider core saturation. In a second step, the implications of further critical aspects on the losses, e.g., temperatures of core and coil, are examined using a comprehensive semi-numerical model. Surprisingly, the evaluation of the losses calculated in the fr domain reveals that nearly minimum inductor losses are obtained for a current ripple that is inversely proportional to the frequency, i.e., for a constant inductance, within a wide frequency range, from 200 kHz to 1 MHz. Furthermore, the investigation reveals a decrease of the losses for increasing frequencies up to 375 kHz, e.g., from 4.32 W at 80 kHz (r = 110 %) to 2.37 W at 375 kHz (r = 18 %). The detailed analysis related to these results enables the compilation of a simple two-equations guide for the design of an inductor that achieves close to minimum losses. In a next step, interesting trade-offs are identified based on a study of the design space diversity, e.g., with respect to low cost and increased partial-load efficiency. The findings of this work are experimentally verified, i.e., the losses of three different inductors are measured with an accurate calorimetric method and at four different frequencies, ranging from 150 kHz to 700 kHz.

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Analysis of a Synergetically Controlled Two-Stage Three-Phase DC/AC Buck-Boost Converter

Cited by 51 publications

References 26 publications

Novel High-Speed Turbo Compressor With Integrated Inverter for Fuel Cell Air Supply

Novel High-Speed Turbo Compressor With Integrated Inverter for Fuel Cell Air Supply

Analysis and performance evaluation of a three-phase sparse neutral point clamped converter for industrial variable speed drives

Minimum Loss Operation and Optimal Design of High-Frequency Inductors for Defined Core and Litz Wire

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