Partial Discharge (PD) is a critical threat to insulation reliability in rotating machines fed with Voltage Source Pulse Width Modulation (VS-PWM) motor drives. With the growing adoption of VS-PWM ...drives in electrified systems, driven by the fast-switching capability and efficiency benefits offered by Wide Band Gap (WBG) devices, it is imperative to design motor stator windings with robust and PD-free insulation. This comprehensive review focuses on elucidating the influence of PWM voltage waveform characteristics of VS-PWM motor drives on PD phenomena, exploring factors such as rise time, frequency, pulse width, voltage shape, and dead time. Additionally, the paper delves into potential reasons explaining the differences in results across various literature and emphasizes the need for a standardized test procedure and setup. Furthermore, the paper reviews various methods adopted in the literature to detect, separate, and quantify PD events under switching frequencies and dv/dt environments. By examining these aspects, this paper contributes to understanding the intricate relationship between VS-PWM drive output voltage and PD-induced stator winding insulation degradation.
Interleaving in a boost converter is beneficial for lowering input and output current ripples through ripple cancellation due to phase-shift between channel currents. However, interleaving does not ...affect the channel current ripple. The channel current comprises circulating Differential Mode (DM) current and Common Mode (CM) boost current, whose ripples constitute the total channel current ripple. Inverse coupling between channel inductors effectively lowers channel current ripple while maintaining the same input and output current ripples. However, with a single inverse coupled inductor, its leakage inductance, which serves as a boost inductor, depends on the winding arrangement and is challenging to balance in both channels. To overcome this, the inverse coupled inductor can be implemented as a cascade of inverse (DM inductance) and direct (CM inductance) coupled inductors. The DM and CM currents and their ripples then depend on CM and DM inductances, respectively. Nonetheless, this approach results in increased size and count of magnetic cores. In this paper, an Integrated Magnetic Structure (IMS), based on a gapped EE-core, is proposed that combines both CM and DM inductances in a single core. The CM and DM inductances are independent and depend on separate winding turns. A reluctance model is derived, and a design procedure is developed where core parameters are expressed in terms of converter parameters. Finally, the proposed IMS concept is validated through a 300 W, 100 V to 168 V prototype, switching at 70 kHz.
A MVDC Hybrid Circuit Breaker (HCB) is proposed in this paper that consists of an electro-mechanical switch (EMS) in series with a Voltage Injector Building Block (VIBB). The VIBB-HCB does not employ ...any semiconductor devices in the main DC line. The VIBB utilizes an E-core-based integrated magnetic structure for injection purpose. The core is unbiased during normal operation, which does not affect system response or add more inductance in the main DC line. Further, the injection circuit is isolated from the main circuit. Hence, any surge or fault current does not impact the injection circuit. The injection circuit comprises a SiC-based full bridge auxiliary converter, which provides fast (μs range) bidirectional fault clearing capability. Moreover, the EMS is opened under zero voltage and zero current, which increases EMS reliability and lifetime. Lastly, the design does not require bulky high rating energy absorption components such varistors due to miniscule post-fault interruption residual energy. A detailed design procedure is derived and validated through Finite Element Analysis using ANSYS Maxwell Transient solver. This is followed by experimental verification on a scaled down hardware prototype.
Power modules are the core components for energy conversion in motor drive, renewable energy application, and battery electric vehicle (EV) and have a significant impact on system performance and ...reliability. A variety of packaging structures are proposed for a number of applications, and however, there is no clear guideline for their performance comparison. To help in selection of wide bandgap MOSFET-based power modules for high-power-density energy conversion system, a new power module figure of merit (PMFOM) is proposed in this article. The PMFOM is derived based on device switching behavior, considering the conduction and switching loss, parasitics from package layout, thermal resistance, and package area. Finally, the validation of the proposed PMFOM is verified with a practical design example using commercially available 1.2-kV power modules.
Wide bandgap (WBG) devices are a desirable choice for high-density energy conversion systems. In high-speed hard-switching applications, voltage overshoot across device terminals, oscillations at ...gate loop, and electromagnetic interference (EMI) become harder to mitigate, and the overall system reliability is reduced. To address the key challenges and harness the benefits offered by these latest generations of devices, improved and advanced packaging structures are required, as packaging technology often has a critical impact on module performance and reliability. This article summarizes the design procedure for power modules, essential parts, and available materials for the fabrication of a power module package. Moreover, it provides a review of commercially available gallium nitride-based high electron mobility transistors (GaN HEMTs) and state-of-the-art module packaging technologies adopted for them with a focus on module layout, module integration trends, and identifying their impacts on the GaN HEMT's performance. Through this review, this article also discusses major challenges faced by designers with GaN HEMTs in power electronics applications and their potential solutions, which is critical for the mainstream adoption of GaN HEMTs and defining the future technology roadmap.
Sustainable materials for 3D concrete printing Bhattacherjee, Shantanu; Basavaraj, Anusha S.; Rahul, A.V. ...
Cement & concrete composites,
September 2021, 2021-09-00, Volume:
122
Journal Article
Peer reviewed
Open access
This paper explores the sustainability aspects of binders used in concrete 3D concrete printing. Firstly, a prospective approach to conduct sustainability-assessment based on the life cycle of 3D ...printed structures is presented, which also highlights the importance of considering the functional requirements of the mixes used for 3D printing. The potential of the material production phase is emphasized to enhance the sustainability potential of 3DCP by reducing the embodied impacts. The literature on the different binder systems used for producing 3D printable mixtures is reviewed. This review includes binders based on portland cement and supplementary cementing materials (SCMs) such as fly ash, silica-fume and slag. Also, alternative binders such as geopolymer, calcium sulfo-aluminate cement (CSA), limestone calcined clay cement (LC3) and reactive magnesium oxide systems are explored. Finally, sustainability assessment by quantifying the environmental impacts in terms of energy consumed and CO2 emissions of mixtures is illustrated with different binder systems. This paper underlines the effect of using SCMs and alternative binder systems for improving the sustainability of 3D printed structures.
Power modules are the core components of the powertrain of hybrid and battery electric vehicle (EV) and has a significant impact on system performance and reliability. Conventional single-sided ...cooled (SSC) wire-bonded power modules have limitation to utilize the benefits offered by new generations of silicon carbide (SiC) devices due to higher parasitic inductance and heat dissipation issues. Planar, low-profile, double-sided cooled (DSC) power modules are emerging in inverters of EV powertrain to address the limitations of conventional SSC modules. However, there is a reliability concern introduced by the rigid interconnection between the device chips and two substrates of the DSC power module. In this article, design, and development of a double-sided cooled, 1200V/150A SiC half-bridge split phase power module has been presented, where flexible compressible pins called "fuzz buttons" are used in a low-profile PCB board to realize die top side connection. Our simulation result shows a 45% reduction of thermomechanical stress at the interposer-dies interface with a total power loss of 1300W (200 W/SiC MOSFET and 125 W/SiC Schottky Diode). The feature of double-sided cooling helps to reduce the maximum junction temperature of the dies by 26%, compared to the single sided cooling. Moreover, vertical commutation loop and utilization of copper layer in PCB based fuzz button retainer board helps to achieve a power loop inductance as low as 1.51 nH.
The rise of wide band gap (WBG) technologies has led to a rise in the electrification of aircraft systems for a sustainable future with lower costs encouraged by favorable governmental policies. ...While WBG is efficient, it introduces overvoltages due to impedance mismatches, risking motor, and cable failure. Moreover, this surge in aircraft electrification stresses electrical wiring interconnect systems (EWIS). This research focuses on the length and frequency-extendable modeling of aircraft cables. The proposed cable model includes the characterization of high-frequency (HF) phenomena such as skin and proximity effect, mutual coupling, and common-mode (CM) parasitic elements. CM parasitic are crucial due to inconsistencies in grounding/shielding approaches, and cable layouts. Furthermore, with the advent of protection and monitoring requirements at the ends of cables serving as "unavoidable additional impedance network" (lead wires), this article studies the impact of infrastructural parasitic and the added impedance network on a reflected wave (RFW) modeling. Notably, this article provides an improved average approximation of the load overvoltage incorporating the impact of lead wires, varying dv/dt of WBG devices, and cable length. Lastly, the study concludes with a rigorous combination of experimentation and simulations, ensuring a comprehensive comparative analysis to validate the effectiveness of the proposed modeling approach.
Gallium nitride (GaN) high electron mobility transistors (HEMTs) are excellent power semiconductor devices due to their superior material properties compared to their silicon (Si) counterparts. It ...has demonstrated a fast switching speed with high dV/dt, enabling the designer to push the switching frequency toward the MHz range. However, traditional wire-bonded packaging becomes a limiting factor in fully harnessing the benefits offered by these advanced power devices, as it is likely to introduce voltage overshoot, oscillation, parasitic turn-on, and electromagnetic interference (EMI) issues; thus, improved and advanced packaging structures are a must to bridge the gap. Besides, the unique electrical behavior and footprint of GaN compared to Si and Si carbide make them have different requirements for power module integration. To seek a viable solution, a globally optimized double-sided cooled, gate driver integrated 650-V/60-A GaN half-bridge power module is presented herein. The proposed 3-D integrated hybrid solution delivers an optimized package, having power loop inductance and thermal resistance as low as 0.91 nH and <inline-formula> <tex-math notation="LaTeX">0.38~^{\circ }\text{C} </tex-math></inline-formula>/W, respectively, which is verified using simulation and experimental results. The overall utility of the design improved proportionately by introducing simple, yet effective electrical/thermal codesign approaches, which can be applied to future power modules, designed for separate applications.
To study the putative effects of Advanced Oxidation Protein Products (AOPPs) and Advanced Glycation End Products (AGEs) in the development and progression of cardiovascular disease (CVD).
AGEs, ...AOPPs, e-NOS, lipid profile, circulating stress and inflammatory biomarkers were evaluated among fifty cardiovascular patients and fifty controls. Independent student’s t-test was done for statistical analysis.
The malondialdehyde mean level in CVD patients (5.45 nmol/ml) was significantly higher than control (1.36 nmol/ml) (p value = 0.018). Nitric oxide in CVD patients (55.72 ng/ml) was remarkably increased as compared to normal subjects (19.19 ng/ml). A significant change in the mean serum level of AGEs in CVD patients (2.74 ng/ml) and normal individuals (0.85 ng/ml) was recorded (p value = 0.000). The AOPPs also showed significant increased levels in CVD group (132.07 ng/ml) in comparison with normal subjects (83.05 ng/ml) (p value = 0.011). The mean eNOS serum level in CVD group (15.50 U/L) was higher than control group (11.28 U/L) (p value = 0.004). Cardiovascular disease patients, in comparison with healthy controls, showed increased level of total cholesterol (5.48 mmol/L vs 4.45 mmol/L), triglycerides (2.59 mmol/L vs 1.24 mmol/L), and low density lipoprotein (2.47 mmol/L vs 2.31 mmol/L) along with decrease in high density lipoprotein (1.39 mmol/L vs 1.74 mmol/L). The mean MMP-11 serum levels in CVD group (98.69 ng/ml) was almost double of control group (45.60 ng/ml) (p value = 0.017). The mean serum level of TNF-α and IL1-α were 32.16 pg/ml and 6.64 pg/ml in CVD patient. The significant decreasing trend of SOD (p value = 0.041), CAT (p value = 0.018), GSH (p value = 0.036) and GRx (p value = 0.029) but increasing drift of GPx (0.023) level was observed in CVD patients.
This study provides strong evidence that CVD patients presented with elevated oxidative stress, enhanced inflammation and lipid profile in their serum. Therefore, the study strongly approves that AGEs, AOPPs, inflammatory and lipoxidative biomarkers hold predictive potential in causing and aggravating the disease, thus by controlling these factors CVD progression can be inhibited.
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