Michael Brubaker

Bio: Michael Brubaker is an academic researcher. The author has contributed to research in topics: Capacitor & Inductance. The author has an hindex of 4, co-authored 12 publications receiving 58 citations.

High Dielectric Constant Polycarbonate/Nylon Multilayer Films Capacitors with Self-Healing Capability

Abstract: With the fast development of high-temperature metal oxide semiconductor field effect transistors for power electronics in electric vehicles, current state-of-the-art biaxially oriented polypropylen...

Capacitor Used as Insulating Spacer for a High Current Bus Structure

Abstract: Parallel plate bus structures are commonly used for high-current applications where low inductance is a requirement. Such bus structures are very well suited for inverter topologies used to convert from DC to AC power and a capacitor is needed to minimize ripple on the DC bus. The present invention provides a method of integrating an annular form factor wound film capacitor into a parallel bus structure to provide a compact geometry with minimal inductance. Furthermore, the capacitor acts as the dielectric spacer between the bus plates, which eliminates the need for separate capacitor terminals and provides the lowest possible profile.

Coaxial Capacitor Bus Termination

Abstract: Parallel plate bus structures are commonly used for high-current applications where low inductance is a requirement. Such bus structures are very well suited for inverter topologies used to convert from DC to AC power and a capacitor is needed to minimize ripple on the DC bus. However, such arrangements are not able to provide sufficiently low inductance to easily eliminate bypass capacitors which typically requires a system inductance below 10 nH nor do they provide any natural EMI suppression. The present invention utilizes that natural circular symmetry of a circular film capacitor winding by implementing a coaxial shaped bus connection from the capacitor to the switching semiconductors in the DC bus application of DC to AC inverter. The result is an achievement of lower ESL and geometry based EMI suppression without the use of external-lumped filtering components.

Integrated DC link capacitor/bus enables a 20% increase in inverter efficiency

Abstract: Voltage overshoot at switch turn-off traditionally limits the DC operating voltage for inverter systems. Mitigation methods include snubber capacitors and intelligent gate control, which add cost and complexity while reducing efficiency. However, the fundamental first step in overshoot reduction is actually minimizing the DC link inductance. The combination of the SBE Power Ring Film CapacitorTM integrated with an optimized bus structure can achieve a DC link inductance below 10nH (approaching 5nH), which is less than typical IGBT half-bridge internal branch values. This enables safely increasing the DC voltage up to 20% as compared to standard configurations, thus improving inverter performance and volume efficiency with existing IGBT's.

Automotive Traction Inverter for Highest Power Density

Abstract: The main drivers for the development of automotive traction inverters can be summarized to be cost, power density, specific power, efficiency and reliability [1], [2]. Nowadays, traction inverters are commonly assembled using individual building blocks serving the system as switch (power semiconductor module), energy storage (DC link capacitor), current distributor (copper bus bar structure) and cooling system (liquid cooled heat sink). In addition sensor functions (Hall elements, thermistors) and control circuits are integrated. In most cases this setup is supported by mechanical parts and protected by an enclosure. Engineers have the demanding task to combine these individual components in a way that enables highest power densities at lowest possible cost. This paper proposes an automotive traction power inverter design concept combining these building blocks into one integrated "mini stack". Electrical connection, thermal interface and mechanical fixing were developed to facilitate each other by using the same mechanical parts for different tasks at the same time. Thus, an optimum in performance is achieved at maximum power density and a minimum of individual parts. The combination of a compact and high performance direct water cooling system, with a laminated bus bar directly bonded to low loss film capacitors leads to highest power densities, while the demanding lifetime requirements of automotive traction applications can still be fulfilled by usage of latest bonding and joining technology [3]. Besides the compact design, this demonstrator is targeting operation with elevated coolant temperature. An approach investigated in this content is the combination of Si IGBT and with SiC diodes.

Dielectric polymers for high-temperature capacitive energy storage.

Abstract: Polymers are the preferred materials for dielectrics in high-energy-density capacitors. The electrification of transport and growing demand for advanced electronics require polymer dielectrics capable of operating efficiently at high temperatures. In this review, we critically analyze the most recent development in the dielectric polymers for high-temperature capacitive energy storage applications. While general design considerations are discussed, emphasis is placed on the elucidation of the structural dependence of the high-field dielectric and electrical properties and the capacitive performance, including discharged energy density, charge-discharge efficiency and cyclability, of dielectric polymers at high temperatures. Advantages and limitations of current approaches to high-temperature dielectric polymers are summarized. Challenges along with future research opportunities are highlighted at the end of this article.

Automotive Traction Inverters: Current Status and Future Trends

Abstract: Traction inverters are crucial components of modern electrified automotive powertrains. Advances in power electronics have enabled lower cost inverters with high reliability, efficiency, and power density, suitable for mass market consumer automotive applications. This paper presents an independent review of the state-of-the-art traction inverter designs from several production vehicles across multiple manufacturers. Future trends in inverter design are identified based on industry examples and academic research. Wide bandgap devices and trends in device packaging are discussed along with active gate driver implementations, current and future trends in system integration, and advanced manufacturing techniques.

Ultrahigh discharge efficiency and improved energy density in rationally designed bilayer polyetherimide–BaTiO3/P(VDF-HFP) composites

Abstract: Polymer dielectric composites are of great interest as film capacitors that are widely used in pulsed power systems. For a long time, huge efforts have been devoted to achieving energy densities as high as possible to satisfy the miniaturization and high integration of electronic devices. However, the discharge efficiency which is particularly crucial to practical applications has gained little attention. With the target of achieving concurrently improved energy density and efficiency, a class of rationally designed bilayer composites consisting of a pure polyetherimide layer and a BaTiO3/P(VDF-HFP) composite layer were prepared. Interestingly, the bilayer composites exhibit ultrahigh discharge efficiencies η (>95%) under external electric fields up to 400 kV mm−1 which are much higher than most of the so far reported results (η < 80%). Meanwhile, a low loss (tan δ < 0.05 @ 10 kHz) comparable to that of the pure polyetherimide is obtained. In addition, the bilayer composites show impressive improvements in breakdown strengths Eb, i.e., 285%, 363%, 366% and 567% for composites with 5 vol%, 10 vol%, 20 vol% and 40 vol% BaTiO3, compared to their single layer counterparts, resulting in obviously improved energy densities Ud. In particular, the bilayer composite with 10 vol% BaTiO3 displays the most prominent comprehensive energy storage performance, i.e., η ∼ 96.8% @ 450 kV mm−1, Ud ∼ 6 J cm−3 @ 450 kV mm−1, tan δ ∼ 0.025 @ 10 kHz, and Eb ∼ 483.18 kV mm−1. The ultrahigh discharge efficiencies and high energy densities, along with low loss and breakdown strengths, make these bilayer composites ideal candidates for high-performance dielectric energy-storage capacitors.