# New DC-Link bus bar and capacitors integration for 800V inverter

Kévin Bernardino, Thomas Fouet

► To cite this version:

Kévin Bernardino, Thomas Fouet. New DC-Link bus bar and capacitors integration for 800V inverter. The 26th European Conference on Power Electronics and Applications, GDR SEEDS France & EPE Association, Mar 2025, Paris, France. 10.34746/epe2025-0008 . hal-05069596

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# New DC-Link bus bar and capacitors integration for 800V inverter

Kévin BERNARDINO¹, Thomas FOUET¹

¹MERSEN Pontarlier, 6 rue Claude Chappe, 25300 PONTARLIER, France

Email: [kevin.bernardino@mersen.com](mailto:kevin.bernardino@mersen.com), [thomas.fouet@mersen.com](mailto:thomas.fouet@mersen.com)

URL: [https://www.mersen.com](https://www.mersen.com)

## Acknowledgements

This project was funded by the French State as part of France 2030, and by European Union as part of France Relance. Authors strong gratitude to the R&D and engineering teams of Punch Powertrain, EFI and all partners of Mautiv'8 project, for their invaluable contributions to this development of safe and reliable DC-Link for 800V inverter. Their hard work and expertise have been instrumental in advancing the field.

## Keywords

Bus bar, capacitors, DC-Link, Simulation, Inverter.

## Abstract

E-mobility faces an increasing need to enhance the performance of electric vehicles (EV). In this context, a project is underway to develop an 800V inverter with high power density. This article focuses on the development of a new DC-Link system, including laminated bus bars, capacitors, and cooling components. The main challenge was meeting capacitance and inductance requirements, within limited volume and thermal limitations of assembled components. This development has resulted in characterized prototypes, validating the results obtained from preliminary simulations. Optimized thermal management ensures the DC-Link temperature is controlled, guaranteeing capacitors lifespan up to 40,000h for an inverter with a nominal voltage up to 900V. This work also includes the Life Cycle Assessment (LCA) of the product, showing that 96% of the greenhouse gases emitted by the product are produced during its operating phase.

## Introduction

The electrification of the vehicle fleet can only accelerate if technological barriers are overcome. In Europe, the sale of internal combustion vehicles is set to end by 2035, and France anticipates having over 13 million electric vehicles (EVs) on the road by 2030 [1]. Many manufacturers, including Stellantis, Mercedes,

Volvo or Lexus, have already begun transitioning to fully electric ranges, with some planning to phase out combustion engines between 2026 and 2035 [2].

In this context, a consortium of 5 French industrial and research partners has been formed to develop an eco-designed traction inverter for road transport, covering both passenger and heavy-duty vehicles. This inverter will utilize 800V technology and feature significant improvements in compactness, weight reduction, electromagnetic compatibility, efficiency, and cost. The goal is to industrialize this advanced inverter in France by 2026, addressing both environmental and operational challenges at the inverter level.

## A - Vehicles autonomy

Historically, voltage in electric cars, such as those produced by Tesla, have operated at 400V. However, the charging speed is limited by the current. Doubling the voltage from 400 to 800V allows for a doubling of charging power, significantly reducing charging time [3]. This evolution is being considered by an increasing number of manufacturers, but it requires careful attention to electrical design. Higher power densities and the need for greater clearance and creepage distances present challenges in an environment where the objective is to optimize volume and significantly increase power density.

## B - End of life and Greenhouse Gas (GHG) reduction

Since transport is responsible for 38% of CO2 emissions in France [4] there is a strong need to decarbonize this sector through the electrification of the car fleet.

Currently, eco-design, repairability and recycling of electronic components are not sufficiently integrated during the conception phase. The electric transition must be accompanied by significant progress in recycling of end-of-life components.
In the context of inverters, including the DC-Link, the main strategies to achieve these goals are:

* Choosing sustainable materials, and/or technologies that reduce weight. Laminated bus bar technology, which involves assembling thin insulation and conductive layers, is a promise approach, although its recyclability must be demonstrated.

* Selecting component assembly technologies that facilitate dismantling at the end of life and reduce energy consumption during manufacturing.

* Since most of the energy consumption of the inverter is due to power dissipation (Joule's law), a significant energy saving can be achieved by optimizing the design to limit overheating of conductors and capacitors. This can be done using simulation tools to predict heating areas and make necessary adjustments.

The first part of this article develops the challenges related to power conversion, the different components of the developed DC-Link and how to assemble its. The second part is related to characterization of the DC-Link, by simulation and measurement of inductance and thermal properties.

# DC-Link for Power inverters

## A – Challenges related to power conversion

Power conversion in electrical vehicles is essential to convert DC power from batteries into AC for electric motor, and vice versa for charging. 800V inverter is a superior alternative to 400V system as it increases power, reduces charging time, and can lower the currents for the same power within a smaller footprint.

The goal of this development, lead by Punch Powertrain company, is to create an 800V inverter that is 2 to 3 times more efficient than current inverters in terms of performance, with a reduced footprint. The target power for this inverter is 270 kW continuous and 400kW for short bursts of 10 seconds, compared to 160kW continuous and 250kW peak power of the 2022 KIA/Hyundai 800V inverter.

<figure><img src="image_2.png" /><figcaption>Fig. 1: Standard design of a DC-Link for inverter</figcaption></figure>

As a result, DC-Link design is challenged by these new challenges:

* First, the voltage can be up to 900V (including peaks), meaning that, considering standards, the clearance and creepage distances are respectively multiplied by 5 and 2 compared to a 400V inverter, thus reinforcing the need for insulation between conductors, but especially electrical insulation with the cooling system.

* Secondly, the continuous voltage passing through the DC-Link is 400-500A, with short peaks reaching 750A. This is significant for a system whose size and weight are being minimized. It is imperative to avoid narrow current passage sections that can cause hot spots. Additionally, an excellent cooling system and thermal management are essential, particularly to limit temperature of capacitors, having as this greatly impacts the component's lifespan [5], as visible in Figure 2, showing lifetime of film capacitors used in the project, in function of the rated voltage, at different temperatures.

<figure><img src="image_3.png" /><figcaption>Fig. 2: Lifetime of a capacitor, depending on the voltage and the temperature</figcaption></figure>

* Lastly, since the main function of the DC-Link block is to bring a capacitive effect to the system, a challenge is to
improve capacitive density of the system (capacitance of 500μF).

To obtain the best volume-to-capacitance ratio, multiple small capacitors should be used and interconnected through a suitable component. Various technologies can be employed for this purpose, but given the high power and voltage requirements, laminated bus bar technology is particularly effective. This approach optimizes power conversion designs by enabling a compact configuration with excellent electrical properties. For instance, laminated bus bars facilitate the link between capacitors and power modules, ensuring efficient power distribution, and minimizing inductance and resistance.

## B – Role of laminated bus bar

Laminated busbars have been used for several decades as an alternative to cables in various industrial and railway applications, like power distribution systems, inverters, and other high-current applications. The principle behind laminated busbars is to layer insulation and conductors together. After the lamination process, the conductors are "encapsulated" between the insulation layers, leading to improved electrical properties [6].

The laminated busbar's primary advantage is its ability to handle higher current densities than traditional cable systems, resulting in a more efficient and compact design. The Figure 3 illustrates the principle of a laminated busbar. It typically shows the various layers of insulation and conductors that are laminated together to create the busbar.

<figure><img src="image_4.png" /><figcaption>Fig. 3: Cross-section of a laminated busbar for industrial applications</figcaption></figure>

This technology enables to easily link different component like capacitors and power modules and offer a wide choice of component assembly such as screwing or different welding technologies like laser welding or US welding. Since conductors are face-to-face, with thin insulation between, this technology is also a good way to minimize inductance of the system.

## C – Capacitor's integration on bus bar

### 1) Capacitors integration

Different types of capacitors can be used for DC-Link assemblies depending on the specific requirements [7]. Generally, active part of the capacitor (coil), is encapsulated into a plastic casing. Then, capacitors are linked to the busbar by soldering of wire terminals, like in Figure 4. These configurations are easy to industrialize, but don't facilitate thermal management of capacitors.

<figure><img src="image_5.png" /><figcaption>Fig. 4: Film capacitors with plastic casing, soldered on laminated bus bar</figcaption></figure>

To improve capacitors assembly, a solution has been developed which involves removing capacitor's casing allowing a direct connection of the coil to the bus bar using welding process, by placing a conductor on each side of the capacitors.

<figure><img src="image_6.png" /><figcaption>Fig. 5: DC-Link with capacitor's coils welded on conductors.</figcaption></figure>

This method allows to have only the useful part of a capacitor, allowing us to reduce the Equivalent Series Resistance (ESR) and Equivalent Series Inductance (ESL) of the capacitor, and to improve heat transfer from the active part of the capacitor to the busbar and cooling system.
Remove plastic casing and potting resin expose the coil to humidity, leading to lose of electrical performances of metalized films [8]. Potting of the DC-Link is needed, to ensure electrical and lifetime performances of the system. Overall, this innovative solution provides an efficient and effective way to address the inductance issue in DC-Link assemblies.

## 2) Capacitance density and design considerations

Regarding capacitance density, using large circular capacitor coils is not efficient, presenting a problem of compactness, with significant free and useless space between capacitors.

As a solution, coils were slightly flattened, to obtain an oblong shape, more favorable to the occupation of the available space to have a more substantial useful space. The Figure 6 shows the flattened coil.

<figure><img src="image_7.png" /><figcaption>Fig. 6: Flattened film capacitor coil.</figcaption></figure>

In the designed DC-Link, 18 capacitors are used, of nominal capacitance of 21.67µF. All capacitors are linked together, into a parallel circuit, giving us a total capacitance of 390µF.

## DC-Link characterization

As part of the design development, thermo-electrical and magnetic simulations are needed to optimize design before prototyping step, focusing estimation of the inductance and over-heating mapping of the bus bars, to identify potential hot spots.

After prototyping, characterization of main properties of the busbar was done. The following work presents simulation and measurement results, and correlation between both.

### A – Inductance

Reducing inductance in DC-Link circuits is crucial for enhancing the performance, reliability, and efficiency of electrical and electronic systems. Lower inductance minimizes transient overvoltage peaks, improves dynamic response, reduces energy losses, and decreases

electromagnetic emissions. This also contributes to system stability.

### 1) Optimizing tabs to reduce inductance

Most DC-Link products on the market feature protruding connection lugs with + and - polarity spaced apart. According to carried out inductance simulations (see Figure 7), this design is not favorable to inductance: challenge was to optimize the geometries of the connection lugs to reduce inductance at their level.

<figure><img src="image_8.png" /><figcaption>Fig. 7: Busbar inductance simulation with protruding connection tabs.</figcaption></figure>

Inductance is directly related to overlapping of the different conductors [9]. The ideal solution is therefore to overlap the connection zones of the power modules to minimize inductance, as shown in Figure 8.

<figure><img src="image_9.png" /><figcaption>Fig. 8: Inductance simulation of a busbar with fully overlapping connection tabs.</figcaption></figure>

This design is challenged by clearance and creepage constraints, making this solution not feasible as it stands. An alternative solution was to adapt design, creating “U-shaped” opening, to keep a partial overlap of the lugs, as shown in Figure 9. This way, it was possible to meet standard requirements of the product (IEC 60664). Inductance simulations for this new design are shown in the next section.

<figure><img src="image_10.png" /><figcaption>Fig. 9: Inductance-optimized tabs design.</figcaption></figure>
## 2) Inductance simulations

Perform inductance simulation is a good way to calculate the inductance of a design to subsequently improve it quickly. For a bus bar, many parameters contribute to the inductance, such as the length and the distance between the output terminals, which must be as small as possible, and design of these terminals, where a strong overlapping between conductors is to consider.

In our case, the inductance is calculated on the 3 terminals destined to be bolted with the power modules (left-side of the DC-Link block in the Figure 10.

<figure><img src="image_11.png" /><figcaption>Fig. 10: Inductance simulation of the DC-Link at 1 MHz.</figcaption></figure>

Finite-element simulations, including inductance calculation is done using COMSOL Multiphysics Software, with AC/DC module. The calculation is done with a frequency of 1 MHz (standard transition frequency between 2 MOFSET states). To simplify calculation, insulation layers are removed, considering they don't have any influence on the inductance. In addition, capacitors are also replaced by shunt to do short circuit instead. Note that this can be source of variation because capacitors have their own self-inductance.

Results are shown in the Figure 7 demonstrating an average inductance of 11nH.

## 3) Inductance measurements

Measuring the inductance in electrical devices is always challenging because it is a very sensitive property, influenced by various factors such as experimental protocol, the cables used, equipment involved, ...

To measure the inductance of the DC-Link, a LCR Meter E4980A from Keysight was used, with a dedicated test fixture for axial lead components. Considering a specific inductance loop, 2 related terminals are connected to the test fixture, as shown in Figure 11.

<figure><img src="image_12.png" /><figcaption>Fig. 11: Inductance measurement of DC-Link using LCR meter</figcaption></figure>

Performing a frequency sweep from 1kHz to 2MHz by reading the impedance Z (in Ω) + θ (in °) is useful to obtain different characteristics of the DC-Link, like the Equivalent Series Resistance (ESR) and the capacitance at every frequency. For the developed DC-Link, these curves are shown in Figure 12.

<figure><img src="image_13.png" /><figcaption>Fig. 12: Impedance Z and self-resistance ESR of the DC-Link in function of the frequency</figcaption></figure>

From general laws of circuit resonance, the inductance L (in nH) is obtained by the following equation:

$$L = \frac{10^9}{(2\pi f_c)^2 C}$$

With:

* L the inductance in nH

* $f_c$ the resonant frequency in Hz

* C the capacitance of the DC-Link in F (Farad)

X and the ESR are respectively the Imaginary part and the Real part of the impedance Z = ESR + jX.
<figure><img src="image_14.png" /><figcaption>Fig. 13: Graphical representation on the complex plan of the impedance Z, the resistance R and the reactance X.</figcaption></figure>

Thanks to the Z representation of the Figure 13, it is possible to calculate with trigonometric formulas X and R (ESR):

$$R = |Z| \sin \left( 2\pi \frac{(90^{\circ} - \theta)}{360} \right)$$

With:

* R the self-resistance (ESR) in Ω

* |Z| the magnitude of the impedance Z in Ω

* θ the phase factor of the impedance Z in °

$$X = \sqrt{|Z|^2 - R^2}$$

With:

* X the reactance in Ω

* R the self-resistance (ESR) in Ω

* |Z| the magnitude of the impedance Z in Ω

Thanks to all these formulas, a capacitance at 1kHz of 390,58 μF was calculated, and finally the inductance L = 12,79 nH.

Project leader, Punch Powertrain, carried out an inductance measurement of the circuit comprising the DC-Link and the power modules. This enabled them to calculate the overall inductance of the circuit using the double pulse method as shown in the figure 14. They found an inductance of 9,94nH, which is like other DC-Links they usually use in their products (between 8 and 10 nH).

<figure><img src="image_15.png" /><figcaption>Fig. 14: DC-Link loop inductance measurement circuit + power module</figcaption></figure>

### 4) Correlation simulation/measures

The simulation gave us a value of 11,82 nH, to compare to a measured value of 12,79 nH. It is less than 10% difference, that is acceptable considering:

* Some model approximations during simulation, like shunt of capacitors. Capacitors has their own self-inductance, probably a bit different than the simulated shunt.

* Interface adaptation to be able to connect the busbar to the test fixture, leading to a slight increase in inductance.

As a perspective, additional tests with another inductance measurement method must be done: the ΔV method. The principle is to send a pulse through the busbar, and to measure some characteristics of the output to apply the following formula:

$$L = \frac{\bar{U} \times \Delta t}{\Delta i}$$

With:

* L the inductance in H

* $\bar{U}$ the average voltage

* $\Delta i$ the difference between the maximum and the minimum current

* $\Delta t$ the duration of the output voltage signal

Some first trials were done (part of the setup shown in Figure 15), but results are not coherent, probably due to noise generated by setup's cables. Improvements are in progress to obtain relevant results.
<figure><img src="image_16.png" /><figcaption>Fig. 15: Part of the inductance measurement setup, using ΔV method.</figcaption></figure>

## B – Thermal management

Limiting the temperature in a DC-Link is essential to guarantee its reliability and longevity. As previously explained, lifetime of the capacitors is closely linked to the operating temperature and voltage. An overheating DC-Link will not only shorter capacitor life, but also cause increased power loss and impaired performance, as the properties of the components can vary with temperature.

### 1) Simulations

Thermal simulations are essential for the proper sizing of products. They allow for the selection of appropriate materials based operating temperatures, the detection of hot spots caused by current flow, and the precise visualization of the temperatures experienced by the components during operation. This detailed thermal analysis enables accurate prediction of the product's lifetime, ensuring reliable and efficient performance.

Simulations are done using finite-element method, with COMSOL Software and AC/DC module.

After modelling, DC-Link is placed in an environment with an ambient temperature of 85°C and the cooling is done with a coolant circuit on the bottom part of the inverter, acting like a cold plate with a temperature of 65°C. Current is injected in terminals (I<sub>DC</sub> = 420A). The first simulation shows temperature is rising a lot at busbar level, leading to significant overheating of capacitors (up to 116°C), as shown Figure 16.

<figure><img src="image_17.png" /><figcaption>Fig. 16: Temperature rise map of the DC-Link with only the inverter cooling.</figcaption></figure>

The heat on the DC-Link came from a hot spot on the input terminal, but the geometry of it is defined by the AC filter terminal and can't be modified. Make the conductor thicker can be an option, but it's not desirable because it will make the capacitors soldering with the busbar harder. In this configuration, the maximum bus bar temperature is 135°C, needing a high temperature resistant insulation. In addition, 2 capacitors heat up to 116°C, which is beyond their maximum permissible temperature. It is not acceptable for a save use of the DC-Link.

Since the geometry of terminals cannot be optimized due to environment constraints, the proposal was to enhance the system's cooling performance. The chosen solution involves using an aluminum casing to improve heat conduction to the cooling system. This also facilitates the resin potting process by enclosing the DC-Link in a closed environment. However, the downside is that aluminum conducts electricity, necessitating improved electrical insulation of the bus bar to ensure it remains insulated from aluminum casing.

Additionally, new simulations integrating this aluminum casing were performed. Focusing on bus bars and capacitors, these simulations demonstrated that the aluminum casing leads to efficient cooling of the DC-Link, as shown in Figure 17.

<figure><img src="image_18.png" /><figcaption>Fig. 17: Temperature rise map of the DC-Link during continuous current condition.</figcaption></figure>

The results of this simulation show a 30°C reduction in temperature compared to not using the aluminum casing. Thanks to this improvement, the temperature on the bus bar is kept below 105°C, a condition to use standard insulation materials, and the temperature on the
capacitors does not exceed 86°C. These conditions fulfill requirements to guarantee the targeted product lifetime of approximately 70 000 hours.

## 2) Correlation simulation/measures

From these developments, prototypes where done (see Figure 5). Next step is to validate thermal behavior of the DC-Link block and comparing it to simulations.

To do that, thermal sensors were included by Punch Powertrain into the DC-Link, on surface and between capacitors, into potting, as shown in Figure 18.

<figure><img src="image_19.png" /><figcaption>Fig. 18: Location of thermocouples in the DC-Link.</figcaption></figure>

To correlate the simulation results with the real case, it is important to have the same environmental conditions and current profiles. A new thermoelectric simulation was therefore carried out to compare it with the test case. Results are on Figure 19.

<figure><img src="image_20.png" /><figcaption>Fig. 19: Temperature rise map of the simulation for real case correlation.</figcaption></figure>

At the same time, measurements are carried out under the same conditions as the simulation, and the results are then compared in the table in Table 1.

There is a significant discrepancy when it comes to comparing the values of the middle thermocouples (A2, B2 and C2) with the simulation, particularly in the 500A case. The hypothesis put forward to explain this discrepancy is that the ESR of the capacitors varies according to the frequency of the current. As the applied current is not a perfect sinusoid, it breaks down into several frequencies and is therefore not subject to the same ESR of the capacitor.

<table><caption>Table 1 - Table comparing simulation results with real-case measurements:</caption><thead><tr><th rowspan="2">Sensor</th><th colspan="2">Tmax [°C] @500Arms</th><th colspan="2">Tmax [°C] @330Arms</th></tr><tr><th>Simulation</th><th>Tests</th><th>Simulation</th><th>Tests</th></tr></thead><tbody><tr><td>A1</td><td>49.80</td><td>49.03</td><td>35.00</td><td>38.67</td></tr><tr><td>A2</td><td>64.30</td><td>47.23</td><td>38.80</td><td>37.67</td></tr><tr><td>A3</td><td>43.90</td><td>37.99</td><td>33.70</td><td>33.95</td></tr><tr><td>B1</td><td>56.50</td><td>54.80</td><td>36.80</td><td>41.06</td></tr><tr><td>B2</td><td>75.70</td><td>51.86</td><td>41.90</td><td>39.59</td></tr><tr><td>B3</td><td>48.50</td><td>41.18</td><td>35.00</td><td>35.38</td></tr><tr><td>C1</td><td>50.10</td><td>53.13</td><td>35.10</td><td>40.16</td></tr><tr><td>C2</td><td>64.70</td><td>52.17</td><td>38.90</td><td>39.65</td></tr><tr><td>C3</td><td>44.20</td><td>41.32</td><td>33.80</td><td>35.49</td></tr></tbody></table>

The other thermocouples may have moved during the potting phase, and as the temperature gradient in Figure 20 shows, changing the position of a thermocouple on the outer edge of the capacitors by a few millimeters can produce a temperature difference of several degrees.

Further research needs to be done in the future, to verify the hypothesis and correlate all the results.

<figure><img src="image_21.png" /><figcaption>Fig. 20: Cross-section of the temperature gradient inside the capacitors.</figcaption></figure>

It should also be noted that the simulation results obtained follow the same logic as a similar study carried out by Bosh [10].

## C - Life Cycling Assessment

With manufacturers becoming increasingly aware of the need to reduce their environmental impact, it's important to be aware of the environmental impact of the electrical products. A useful tool to evaluate environmental impact of products, from the cradle to the grave, is life-cycle assessment (LCA).

This DC-Link is designed for EV trucks and has an estimated life of 40,000 hours. Of these 40,000 hours, 50% are for driving, 6% for fast charging and 44% for slow charging.

Performing a thermoelectric simulation of these 3 typical cases then allows us to obtain the power losses in the busbar, and therefore to calculate the
busbar's energy consumption, as shown in Figure 21.

<figure><img src="image_22.png" /><figcaption>Fig. 21: Visualization of current densities in the bus bar, a phenomenon directly linked to power losses.</figcaption></figure>

Thanks to the bill of materials, including recycling rates (which has a major impact on the environmental balance sheet) [11] and the processes used to manufacture the product, LCA could be done. A dedicated software is used (EcoEvent), able to analyze precisely environmental impact, considering different indicators. Main results are summarized in Table 2, with distribution at different stage of the product life.

<table><caption>Table 2 - Compilation of LCA results regarding climate change indicator:</caption><thead><tr><th rowspan="2"></th><th colspan="2">Climate change [eq. kg CO2]</th></tr><tr><th>R</th><th>%</th></tr></thead><tbody><tr><td>Manufacturing</td><td>2.59</td><td>1.30</td></tr><tr><td>Distribution</td><td>0.0422</td><td>0.02</td></tr><tr><td>Installation</td><td>0</td><td>0</td></tr><tr><td>Use</td><td>191</td><td>96.03</td></tr><tr><td>End of life</td><td>5.25</td><td>2.64</td></tr><tr><td>Sum</td><td>199</td><td>100</td></tr></tbody></table>

The main part of environmental impact is due to the use phase (96%), related to power losses during operations. This part varies according to how the electricity used to power the electric vehicle is produced but is still largely dominant.

Other phases, including manufacturing or recycling, represent only a small part of the impact, and efforts should therefore focus mainly on optimizing the design of products intended to carry current, so that they generate less power loss through the Joule effect.

Other indicators could be followed, giving more information on specific topics. For example:

* Ecotoxicity of freshwater (PEF-CTUe)

* Human toxicity, cancer (PEF-CTUh-c)

For indicator like Human toxicity, main impact is during recycling phase, linked to recycling of adhesives and inks that could contain low quantities of carcinogenic products.

## Conclusion

This study describes the design of a DC-Link for news 800V inverters, addressing the growing need of electrical vehicles manufacturers for more powerful inverters to integrate with high-power electric vehicles, such as trucks. The use of laminated busbar combined with capacitor coils directly welded on conductors, allow to address main requirements of this kind of component:

* A nominal voltage of 900V

* an Equivalent Series Inductance (ESL) <13nH,

* A capacitance of 390μF,

* An optimized design for smart integration and efficient cooling

* A lifetime of 40,000h,

A comparison between simulations and measurements showed a good correlation between calculated and measured inductance, while comparison between thermal simulation and measurement shows that the simulation tends to overestimate overheating, so it's likely that performance is better than expected. Future investigation will consist to affine models and measurement setups for a stronger correlation.

These simulations also provide a valuable approach to identifying more relevant design improvements, particularly in thermal management. By optimizing terminals design to reduce the current density in some hot spots, the need for powerful cooling can be minimized.

By analyzing the key features of the DC-Link, including the assembly method of the capacitors, the compact design, and the low inductance, it was established that this solution offers significant advantages over current market options.

As a first step of an eco-design approach, the life-cycle assessment of the DC-Link was done, showing that environmental impact is 96% linked to use in terms of greenhouse gas emissions. Main axis for future works will be to improve design,
to limit as far as possible its power losses, which
are converted into thermal energy.

Future activities, supported by Punch Powertrain
and Mersen, will also address cooling
performances, needed to maintain a good service
life, but also significantly reducing its energy
balance.

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