One particular of the indisputable facts about the automotive market is that the overall digital system material in automobiles is expanding.
As automobiles turn into extra advanced and include things like features that perception, feel and act for the driver, the kind of digital material improvements. In specific, there will be enormous growth in hybrid electric powered motor vehicle and electric powered motor vehicle material, as properly as for automated travel features.
On the other hand, a critical difficulty that needs to be resolved is that the present company design for electric powered automobiles is not worthwhile prolonged term for OEMs. The typical believed cost for base electric powered automobiles is nevertheless a big worry.
OEMs will be seeking to near this hole by bringing extra style back again in-property, or by bypassing Tier 1 suppliers to converse right to IC suppliers. The disrupter in this article will be to integrate embedded digital architectures by combining ECUs and clustering features in a new way.
This is why NXP is working carefully with companions across the market to speed up how these constraints are fulfilled. One particular way is by producing reference models that mix our system know-how with our protection skills. This indicates that reference models include things like critical protection system components from the outset.
To produce protection ideas for system reference models, NXP has to be equipped to define the protection goals, principle and features for the meant item to be equipped to determine the ideal system implementation into our system style.
We do this by adhering to the ISO 26262 enhancement course of action. This offers suggestions for every single stage alongside the enhancement course of action for protection system products with a V cycle challenge administration resource.
The V cycle groups every single stage as a Portion and precise do the job products are predicted at every single amount. IC suppliers like NXP can foresee and produce system ECUs just like a Tier 1 supplier does. By accomplishing this, we can velocity enhancement time and offer standard deliverables that are of advantage throughout the enhancement chain.
The purpose is not essentially to offer a option with the very same amount of maturity that a Tier 1 could offer, rather to speed up the enhancement of the do the job products for the Tier 1.
Let’s take into account as an instance, how to produce a protection principle for a ability inverter module as a SEooC for an EV software. As an IC supplier, we would do the job by way of areas three, 4, five, 6 and seven of the V cycle and offer the do the job products involved to every single section. We start by defining the item inside the concentrate on system – i.e. what are the likely dangers and protection goals that we want to use to our reference style?
Figure 1: HV Inverter for EVs
As figure 1 exhibits, the ability inverter is the major traction system of an electric powered motor vehicle. It controls the vitality conversion between the electric powered vitality supply and the mechanical shaft of the electric powered motor, primarily based on the torque request from the Automobile Handle Unit (VCU).
The VCU interprets the driver needs into acceleration or deceleration of the electric powered motor. The inverter translates the torque request into phase currents going into the traction motor.
In a battery electric powered motor vehicle, this connection is generally created with a basic gearbox devoid of a clutch. This is our 1st assumption. It is crucial to be precise in this article, since the protection case would be diverse if the motor vehicle has a clutch.
In our case, if a hazard need to come about, it is impossible for the driver or the electrical system to quit the traction of the motor vehicle by basically opening the connection between the electric powered motor and the wheels of the vehicle.
We also need to determine attainable resources of EE malfunction – whether due to driving or non-driving scenarios. These dangers are then rated by chance amount according to the ASIL degrees laid out in ISO 26262. As revealed in figure two, in this case a protection purpose could be to prevent unintended acceleration if the motor vehicle is stopped.
Figure two: Examples of dangers and protection goals for an EV HV inverter
These protection goals lead to a purposeful protection architecture with purposeful necessities (FR) and purposeful protection necessities (FSR) with involved ASIL degrees and FTTI this kind of as:
|FR1||The Inverter shall analyze the request from VCU, then command the adhering to features accordingly: traction, brake and battery regeneration.||ASIL D||FTTI
|FSR1||The inverter shall check the torque request from the VCU and notify in case of unforeseen benefit.||ASIL D||FTTI
Figure three: Functional protection architecture
Now that we have the purposeful protection architecture, figure three, we need to exhibit that the system architecture will be equipped to fulfil the protection necessities and style constraints.
To do this, we derived a technical protection principle from the purposeful protection principle. This brings together the components and application sub-ingredient features that will be used to obtain the meant item and system features.
A protection investigation is then run to check that all attainable system failures have been identified and that the proper protection mechanisms are in area. This may well final result in new protection necessities becoming allotted to the protection architecture.
By accomplishing this, the technical definition can offer the necessary proof that the proper reactions have been identified and that a harmless point out can be attained in significantly less time than FTTI: for that reason that there is no violation of the protection goals of the item.
In our instance, harmless point out is sophisticated for the reason that of the higher quantity of vitality flowing into the electric powered motor. A harmless point out in this article indicates stopping the propulsion of the motor vehicle, by opening or shorting the a few phases of the motor based on the velocity of the motor.
As we progress by way of the V cycle, the do the job products are developed to guarantee the protection concerns a buyer may well have are fulfilled. A components style is included by the course of action in the very same way the protection principle lessens the enhancement and prototyping phase for prospects by a few to six months.
In the NXP reference style, the comprehensive protection architecture is built out using NXP ICs and diagnostics and reaction to harmless point out are examined. The reference style will help to velocity enhancement and offers a amount of technical protection architecture, alongside with proof of the protection integrity amount as section of the overall bundle.
Locate out extra about the ability inverter reference style in this article.