Romina Rodriguez

The design of the thermal management solution has a significant impact on the reliability and power density of power electronics (PEs). As the electric vehicle (EV) industry moves toward increasing the efficiency and output power, the cooling system must effectively remove the excess heat dissipated in PEs. The main heat-generating components are the semiconductor switches, but other components, such as bus bars and power capacitors, also dissipate heat and require cooling. Currently, indirect, direct, and double-sided cooling methods are the most common in EVs and account for 14%–33% of the total volume of traction inverters. However, PE packaging sizes are expected to decrease, while the heat dissipation continues to increase; hence, advanced cooling technologies are being investigated. This article aims to review the thermal management strategies for major PE components in EVs as well as their failure modes since high temperatures can be detrimental to the performance of PEs. Cooling designs that are currently implemented in EVs and future cooling trends for the next generation of PEs are reviewed as well.

With the application of wide-bandgap devices, the packaging technology of power modules is faced with elevated challenges. This article proposes a new packaging concept for silicon carbide (SiC) power modules. The main objective is to improve the lifetime and temperature range, while the proposed packaging also has the potential to reduce stray inductance and simplify the fabrication process. In the proposed concept, sintered nano-silver is selected as the die bonding. The conventional direct-bonded copper substrate is replaced by a molybdenum layer and a bismaleimide triazine resin layer which has a low thermal expansion coefficient. A steady-state thermal–mechanical analysis is conducted to verify the material selection. Furthermore, a transient thermal–mechanical analysis based on Joint Electron Device Engineering Council (JEDEC) temperature cycling methods is carried out, whose results are applied in the Coffin–Manson lifetime model to evaluate the advantages of the proposed silver-sintered molybdenum packaging. The results demonstrated that the proposed packaging technology could improve the lifetime by over 1000 times and increase the maximum operating temperature by nearly three times. Finally, a feasible process of sintering SiC chips on molybdenum substrates is proposed, which achieves a uniform and low porosity bonding.

Effective thermal management of power electronics in electric vehicles is essential for reliability and increased power density. Currently, traditional cooling technologies such as cold plates and heat sinks have been utilized by the automotive industry. As the next generation of power electronics implement wide bandgap devices, however, increased heat fluxes will require more advanced cooling strategies. Recently, jet impingement has gained attention as an advanced cooling technique for power electronics due to its proven thermal performance in high heat flux applications. This paper aims to review the state-of-the-art jet impingement designs applied for power electronics cooling, as well as review future jet impingement technology. Important factors for widespread implementation such as heat transfer, pressure drop, and reliability are discussed, along with the current technical gaps and challenges for jet impingement research in electrified transportation.

With the aim towards lighter and more efficient electrical systems in future aircraft, design of DC/DC converters with high efficiency, power density and improved thermal management becomes necessary. This paper investigates the detailed design of isolated bidirectional DC/DC converters for more electric aircraft (MEA). Use of wide bandgap (WBG) devices to enhance system efficiency is considered. A transformer optimization technique based on switching frequency for different converter topologies is investigated. The control strategy of the discussed configurations are verified in the PLECS simulation environment. Dual active bridge (DAB), input-series output-parallel (ISOP), neutral point clamped (NPC) and active neutral point clamped (ANPC) converters are considered to exploit benefits offered by WBG devices for MEA. A comparison is performed in terms of efficiency, thermal management, power density and electromagnetic interference (EMI). The results indicate that the ANPC converter is better for efficiency, thermal management and power density. The DAB converter showed similar results to the ISOP with the DAB yielding higher efficiency. The NPC and ANPC configurations resulted in the best EMI performance. The NPC converter proved to be the least effective solution with regard to efficiency, thermal management and power density.

To meet the upcoming challenges of higher power density and higher efficiency for power electronics, a system level approach to the design of power electronic devices must be carried out. Higher system integration and packaging will allow for more compact designs but will also result in challenges for component manufacturing and thermal management. Additive manufacturing can potentially mitigate some of these challenges due to the design flexibility and intricate features that additive manufacturing methods can provide. This paper presents an overview of the additive manufacturing technologies currently in practice at the academic and industry level. A detailed review is presented of current applications of additive methods for the production of power electronic components, advanced heat exchanger designs and integrated power electronic systems.

Semiconductor power modules are core components of power electronics in electrified vehicles. Packaging technology often has a critical impact on module performance and reliability. This paper presents a comprehensive review of the automotive power module packaging technologies. The first part of this paper discusses the driving factors of packaging technology development. In the second section, the design considerations and a primary design process of module packaging are summarized. Besides, major packaging components, such as semiconductor dies, substrates, and die bonding, are introduced based on the conventional packaging structure. Next, technical details and innovative features of state-of-the-art automotive power modules from major suppliers and original equipment manufacturers are reviewed. Most of these modules have been applied in commercial vehicles. In the fourth part, the system integration concept, printed circuit board embedded packaging, three-dimensional packaging, press pack packaging, and advanced materials are categorized as promising trends for automotive applications. The advantages and drawbacks of these trends are discussed, and it is concluded that a preferable overall performance could be achieved by combining multiple technologies.

High-power boost converters offer significant benefits to hybrid and electric vehicles, because higher-voltage propulsion power equates to lower motor losses. However, the converters themselves must have high efficiency and high power density in order to make the system-level trade-off beneficial. Thus, this paper presents an optimized design process of high power multi-phase interleaved bidirectional boost converters. In order to achieve a fast and accurate analysis and design, a generalized method is developed for the calculations of required phase inductance and output capacitance. In addition, a genetic algorithm (GA) optimization method is implemented for the inductor design. Using the proposed design process, a 3-phase 60kW interleaved converter is designed and tested using paralleled SiC MOSFETS. The converter achieves peak efficiency of 99.2% at 10kW and is > 98% efficiency from 5% to 100% load. The resulting power density is 9.4 kW/L, which can be further improved to 12.2 kW/L with alternate terminal connectors.

Optimal thermal management system design is critical for power electronic converters to ensure the reliability of power semiconductor switches. Medium power density inverter systems are often air-cooled to ensure an efficient and cost-effective thermal management solution. In addition, using heat pipes as the heat transfer medium between the heat sources and the heat sink can provide lower volume for the entire inverter. This paper investigates the effectiveness of Teaching Learning Based Optimization (TLBO) for finding the optimal forced-air heat sink with heat pipe cooling system to achieve higher fan efficiency and lower inverter packaging volume. The optimal design is found utilizing commercially available fans and heat pipes. The TLBO design optimization is also compared to the highly implemented Particle Swarm Optimization (PSO) and it is found that TLBO uses 20 times fewer iterations than PSO to converge, and that the TLBO results are more robust for different design constraints.