Feature: Automotive Design
A lower gauge wire is also lighter
in weight and runs cooler, improving the vehicle's efficiency. It also reduces the amount of copper needed to build the EV and the associated charging infrastructure, including the electricity substations and step-down transformers, which has been a major concern. Unfortunately, OEMs cannot simply swap out a 400V battery with a higher voltage battery, there are knock- on effects.
Implications of higher battery voltages Adopting higher-voltage batteries requires more advanced silicon power semiconductors, such as silicon carbide (SiC), to enable higher-frequency switching and reduce power losses, thereby obtaining higher efficiencies. Despite the higher costs associated with SiC components compared to traditional silicon devices, they are crucial when it comes to enhancing the performance of EVs. Furthermore, as seen in power supply
design, a higher voltage requires greater creepage and clearance spacings to ensure safety. And, at 800V, the passive components are much larger, taking up valuable real-estate. An EV uses roughly double the
number of semiconductors compared to a traditional ICE model. These devices sit primarily in the electric powertrain, specifically within the regenerative braking system. All of these new 800V parts will require intrinsic design and rigorous testing before being put into mass production.
Testing 800V EV components and systems Carmakers employ ISO (International Organisation for Standardisation) standards, such as ISO 16750-2, ISO 7637-2, and DIN 40839, to test 800V EV components and systems. Developed over time, these standards ensure that automotive systems will operate and continue to operate reliably through various scenarios across many years of customer use.
Figure 1: High power programmable power supplies in TDK-Lambda’s GENESYS+ series operate from 0 to 1000V and 0 to 1500V
Tests include voltage surges,
temperature assessments and full system testing. Furthermore, these electronic components, systems and software will require extensive simulation using hardware-in-the- loop (HIL) software. Significant testing during the development and production of new vehicles is crucial to ensuring top performance and durability. Programmable power supplies,
like TDK-Lambda’s 5kW and 7.5kW 1U high models in its GENESYS+ series, which are capable of operating from 0 to 1000V and 0 to 1500V, can effectively test these 800V EV powertrains, see Figure 1. These units offer test engineers additional capability to apply surge testing above the system’s nominal 800V. Many programmable power supplies
offer the ability to parallel units to provide additional output power. Typically, this involves using an analogue signal for communication to ensure the load current is shared between each unit. However, this can impact the transient load response times, degrading the output voltage performance when the load is rapidly changed from high to lower currents. Additional programming may, therefore, be required to set the main controller between the power supply units. To overcome this challenge, the GENESYS power supplies employ a simple parallel data-link cable to connect multiple units together, supplying up to 60kW. The units automatically configure and set their parameters accordingly, displaying the
total current in the uppermost unit. This digital control reacts faster to dynamic load changes than an analog signal can, resulting in much smaller over and undershooting of the output voltage. Utilising higher voltages at high power
levels can provide significant safety challenges. It is, therefore, important to have suitable safety features available in the programmable power supply. For example, programming in safe or automatic re-start conditions on the GENESYS+ power supplies ensures that, after an AC supply outage, the units will or will not automatically continue to supply the output voltage. Last-setting memory and built-in protection functions for voltage, current and temperature are also provided. EV test engineers also have the option to lock the front panel controls from unauthorised adjustment or select a blank front panel if the unit is programmed remotely. Furthermore, arbitrary waveform test profiles of up to 100 steps can be generated and stored in the four memory cells.
The road ahead EV manufacturers are shifting towards 800V systems to reduce current draw, improve efficiency, and decrease the weight of vehicles. However, this transition requires advanced silicon power semiconductors like SiC and adherence to safety standards such as ISO 16750-2 and ISO 7637-2 for testing. Programmable power supplies are crucial for testing these high-voltage EV powertrains effectively and ensuring reliable testing and development of 800V EV components and systems.
www.electronicsworld.co.uk October 2024 23
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50
