Sponsored by Pickering Interfaces.
The following energy structure of selection for EVs is 800 V, which requires parts to be suitably rated and extra sturdy than their 400 V counterparts. Nonetheless, most take a look at tools used for 400 V EV system growth could be re-used for 800 V if it could possibly deal with the upper voltages, making the transition simpler for EV builders.
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The Advantages of {Hardware}-in-the-Loop and Simulation
In EV growth, many corporations use {Hardware}-in-the-Loop (HIL) Simulation as a part of a test-driven technique. HIL simulation permits {hardware}, equivalent to a Battery Administration System (BMS), to work together with a simulated atmosphere that mimics real-world circumstances, together with bodily elements like temperature and dynamic circumstances like movement and vibration. This helps engineers observe system conduct beneath lifelike situations.
Simulating these real-world circumstances allows early identification of design flaws and weaknesses, permitting for well timed enhancements and avoiding expensive points later in growth. A key benefit of simulation in EV growth is the power to securely create excessive fault circumstances—equivalent to fast discharging and quick circuits—to guage BMS conduct with out risking injury to precise battery packs.
Making a HIL Check Platform
Whereas a HIL take a look at platform might be created from scratch, the associated fee (each financial and time) of doing so tends to be prohibitive within the automotive {industry}. Due to this fact, the usage of an industry-standard platform is very really helpful. Two requirements to think about are PXI and LXI, that are based mostly on the PCI and Ethernet {industry} requirements, respectively.
Each are supported by a lot of world distributors with many business off-the-shelf merchandise obtainable. Each present seamless vendor-independent plug-and-play. Of nice profit is that product longevity is assured, and the distributors have obsolescence administration processes in place.Â
400 to 800 V Testing Migration Path
Many OEMs and techniques homes within the automotive sector have invested in growth and verification tools, together with HILS techniques, for EVs. The excellent news for these utilizing PXI or LXI platforms is that many current modules will nonetheless be usable when transitioning from a 400 V to an 800 V structure, permitting for vital reuse of the take a look at system.
For parts that want substitute because of larger voltage scores, PXI and LXI’s modularity and scalability make it simple to swap them out for upgraded variations.
Beneath, we talk about a couple of Pickering Interfaces merchandise appropriate to be used in 800V architectures.
Battery Cell Simulation
Cell-level simulation is important for EV growth, because it permits the Battery Administration System (BMS) to acknowledge a totally charged pack precisely. This requires simulating particular person 3.2 to three.7 V cells and stacking them to realize the required voltage—96 cells for 400 V and 192 cells for 800 V.
The BMS additionally manages cell balancing, necessitating the power to simulate every cell’s cost stage throughout relaxation, charging, discharging, and introducing imbalances.
By simulating cells independently, current tools could be tailored for 400 V and 800 V architectures by including extra modules (simulated cells) so long as the emulator can deal with larger voltages.
Determine 2 reveals the block diagram of a multi-channel battery simulator module obtainable in PXI (41-752A) and PXIe (43-752A). It contains a number of energy provide channels (two, 4 or six per slot) able to supplying as much as 7V and 300mA, that are remoted from each other and from system floor. Due to this fact, the module’s energy provides can be utilized to emulate a stack of battery cells. Additionally, every channel can sink as much as 300mA to emulate a battery beneath cost. Every channel supplies impartial energy and sense connections, permitting the simulator to sense a distant load and proper for wiring losses.
Excessive Voltage Switching
Excessive voltage switching is utilized in take a look at techniques for connecting or disconnecting alerts and routing them between factors, achieved via three configurations:
- Uncommitted switches (e.g., single-pole, single-throw, usually open or closed).
- Matrices that join any enter to any output.
- Multiplexers (MUXs)Â that join a single enter to a number of outputs.
These configurations are available varied relay and connection counts, with modules able to switching a number of kV, making them appropriate for functions like isolation switching and breaker simulation.
Excessive-voltage switching could be achieved utilizing a number of options from Pickering Interfaces: over 60 PXI/PXIe modules and 28 LXI modules. For instance, the 40-323-901 (PXI) and 42-323-901 (PXIe) are 14xSPST relay modules appropriate for high-voltage energy switching functions. They’ll deal with present as much as 0.25 A for chilly switching as much as 9 kVDC (9 kVAC peak) and for warm switching as much as 7.5 kVDC (7.5 kVAC peak).Â
RTD Simulation
Temperature have to be monitored at varied places in an EV, together with the battery pack, motors, energy inverter, charger port, and cabin. A well-liked and cost-effective possibility is the resistance temperature detector (RTD), with the PT100 being a standard kind with a resistance of 100Ω at 0°C. RTDs can have both a constructive or detrimental temperature coefficient (PTC or NTC).
Simulating RTDs is helpful since testing the design beneath a variety of temperatures would in any other case require costly environmental take a look at chambers.
PXI-based RTD simulator modules can be found from a number of corporations. For instance, Pickering Interfaces has many appropriate modules for RTD simulation, together with the 40-263 (with 4, 8, 12, 16, 20 and 24 channels) that may simulate the resistance vary 40 to 900Ω, which equates to a temperature vary of -150 to 850oC, to a decision of lower than 10mΩ. Determine 3 reveals an instance module.
To a lesser diploma, thermocouples are additionally utilized in EVs, primarily in product growth, because of their excessive accuracy. Their outputs, that are small voltages (a couple of millivolts), could be simulated. Pickering Interfaces presents PXI millivolt thermocouple simulator modules with 8, 16, 24, or 32 channels, offering extremely correct low-voltage sources. Every channel can function throughout three voltage ranges to simulate any customary thermocouple kind used within the {industry}.
Fault Insertion/Injection
The power to insert faults throughout system growth and verification is important. As talked about above, techniques may have to instigate a protected shutdown or, if redundancy is inbuilt, energy re-routed if a fault is detected. This performance must be absolutely validated.
Pickering Interfaces’ vary of PXI fault insertion models is explicitly designed for safety-critical functions the place the conduct of a management system, equivalent to a BMS, must be completely evaluated beneath all potential real-world fault circumstances.
For instance, the 40-592 fault insertion break-out (FIBO) is a large-scale, high-density switching matrix. It’s one among a variety of modules designed for functions requiring the simulation of a wide range of faults in advanced designs with a excessive variety of alerts/connections, equivalent to a battery pack.
Open circuits and quick circuits (to a different sign/element or to the bottom) are typical faults that may be simulated.
Abstract
Shifting from 400 to 800 V architectures presents advantages like larger efficiency and quicker charging. Nonetheless, it requires higher sturdiness and security. Simulation is the most secure option to confirm an EV’s structure and techniques, permitting for straightforward take a look at circumstances and outcomes traceability. Utilizing PXI and LXI-based take a look at tools supplies producers with a simple migration path. This permits optimizing key system parts and accelerates system growth via automated testing.
