This paper presents the design of a compact 45 V-to-54 kV dc-dc converter for high-energy beam applications with the focus on X-ray generation. We describe key design choices for a high power density including a modular structure, high-frequency switching, planar transformers and Dickson topology. High-voltage insulation and thermal management are also described in detail. The experimental data with a 5 kV single module and a 10-module 54 kV converter indicate that the proposed structure can generate high dc voltage while achieving a several times higher power density compared to commercial high-voltage power supplies.
more »
« less
Virtual Prototyping Process For Assessment of Medium Voltage Grid-Connected Solid State Transformer Implementations
This paper presents a unique Virtual Prototyping Process (VPP) that allows for metaheuristic optimization of the building block based Power Electronic Converter systems. The VPP allows for exploration of a range of design space variables, including voltage levels, power semiconductor device technology and thermal management approach against competing objectives such as power density, efficiency and specific cost given electrical and environmental constraints. A unique feature of proposed VPP is compilation of lower voltage building blocks into a much higher voltage rated system and inclusion of allocations for insulation systems, thermal management, accessibility, busing/interconnections and frame/structure/chassis. This approach enables understanding of these practical considerations on power density. This paper presents a use case of a Medium Voltage ac (MVac) to Low Voltage dc (LVdc) solid state transformer.
more »
« less
- Award ID(s):
- 1939124
- NSF-PAR ID:
- 10316404
- Date Published:
- Journal Name:
- 2021 IEEE Energy Conversion Congress and Exposition (ECCE)
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Abstract Benefitted from progress on the large-diameter Ga 2 O 3 wafers and Ga 2 O 3 processing techniques, the Ga 2 O 3 power device technology has witnessed fast advances toward power electronics applications. Recently, reports on large-area (ampere-class) Ga 2 O 3 power devices have emerged globally, and the scope of these works have gone well beyond the bare-die device demonstration into the device packaging, circuit testing, and ruggedness evaluation. These results have placed Ga 2 O 3 in a unique position as the only ultra-wide bandgap semiconductor reaching these indispensable milestones for power device development. This paper presents a timely review on the state-of-the-art of the ampere-class Ga 2 O 3 power devices (current up to >100 A and voltage up to >2000 V), including their static electrical performance, switching characteristics, packaging and thermal management, and the overcurrent/overvoltage ruggedness and reliability. Exciting research opportunities and critical technological gaps are also discussed.more » « less
-
null (Ed.)Efficient high-conversion-ratio power delivery is needed for many portable computing applications which require sub-volt supply rails but operate from batteries or USB power sources. In such applications, the power management unit should have a small volume, area, and height while providing fast transient response. Past work has shown favorable performance of hybrid switched-capacitor (SC) converters to reduce the size of needed inductor(s), which can soft-charge high-density SC networks while supporting efficient voltage regulation [1-5]. However, the hybrid approach has its own challenges including balancing the voltage of the flying capacitor and achieving safe but fast startup. Rapid supply transients, including startup, can cause voltage stress on power switches if flying capacitors are not quickly regulated. Past approaches such as precharge networks [3] or fast balancing control [5] have startup times that are on the order of milliseconds. This paper presents a two-stage cascaded hybrid SC converter that features a fast transient response with automatic flying capacitor balancing for low-voltage applications (i.e., 5V:0.4 to 1.2V from a USB interface). The converter is nearly standalone and all gate drive supplies are generated internally. Measured results show a peak efficiency of 96.9%, <; 36mV under/overshoot for 1A/μs load transients, and self-startup time on the order of 10μs (over 100× faster than previous works).more » « less
-
Abstract Solar near-infrared (NIR) selective glazing systems have been proposed by incorporating photothermal effects (PTE) of a nanoparticle film into building windows. From an energy efficiency perspective, the nanoscale PTE forms unique inward-flowing heat by heating up the window interior surface temperature under solar near-infrared, significantly improving the window thermal performance. Also, the PTE-driven solar heat gains are dynamic upon solar radiation and weather conditions. However, the PTE on annual building energy use has not been investigated thoroughly, due to the lack of an accurate and appropriate energy simulation method. In this study, we used the EnergyPlus energy management system to develop a parametric energy model and simulation approach in which a solar-temperature-dependent thermal model was embedded into the parametric energy simulation workflow. Applying this method, we examined the solar near-infrared-dependent PTE-induced thermal performances of glazing systems and their effects on annual heating energy use in representative cold climates (i.e., Zones 4, 5, and 6). The results show that the dynamic model considering the PTE demonstrated more heating energy savings, up to 11.64% in cold climates, as opposed to the baseline model that ignored the PTE. This work presents a method to model and simulate the dynamic thermal performance of windows with PTE.more » « less
-
Voltage control in modern electric power distribution systems has become challenging due to the increasing penetration of distributed energy resources (DER). The current state-of-the-art voltage control is based on static/pre-determined DER volt-var curves. Static volt-var curves do not provide sufficient flexibility to address the temporal and spatial aspects of the voltage control problem in a power system with a large number of DER. This paper presents a simple, scalable, and robust distributed optimization framework (DOF) for optimizing voltage control. The proposed framework allows for data-driven distributed voltage optimization in a power distribution system. This method enhances voltage control by optimizing volt-var curve parameters of inverters in a distributed manner based on a cellular computational network (CCN) representation of the power distribution system. The cellular optimization approach enables the system-wide optimization. The cells to be optimized may be prioritized and two methods namely, graph and impact-based methods, are studied. The impact-based method requires extra initial computational efforts but thereafter provides better computational throughput than the graph-based method. The DOF is illustrated on a modified standard distribution test case with several DERs. The results from the test case demonstrate that the DOF based volt-var optimization results in consistently better performance than the state-of-the-art volt-var control.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.1109/ECCE47101.2021.9595786
