EMC and Functional Safety of Automotive Electronics
Electromagnetic compatibility (EMC) deals with the unintentional propagation and reception of electromagnetic energy which may cause disturbances or even physical damage in electronic or electromechanical systems. With the increase in number and density of electronic devices and systems in modern vehicles, EMC has become a substantial concern and a key cause of malfunction of automotive electronics. This book explores electromagnetic compatibility in the context of automotive electronics, with a close relation to functional safety as required by ISO 26262. Topics covered include an introduction to automotive electronics; electrical drives and charging infrastructure; fundamentals of functional safety; fundamentals of EMC, signal and power integrity; the legal framework; EMC design at the ECU Level; EMC design at the system level and in special subsystems; modelling and simulation; and test and measurement for EMC.
Inspec keywords: road safety; electromagnetic compatibility; automotive electronics
Other keywords: development process; electromagnetic compatibility; ISO 26262; power integrity; automotive industry; signal integrity; safety life cycle; automotive electronics; V-model; EMC design flow; functional safety
Subjects: Electromagnetic compatibility and interference; Automobile electronics and electrics
- Book DOI: 10.1049/PBTR012E
- Chapter DOI: 10.1049/PBTR012E
- ISBN: 9781785614088
- e-ISBN: 9781785614095
- Page count: 250
- Format: PDF
-
Front Matter
- + Show details - Hide details
-
p.
(1)
-
1 Introduction to automotive electronics
- + Show details - Hide details
-
p.
1
–41
(41)
This chapter does not deliver an exhaustive treatment on automotive electronics. There are other books on this topic (e.g. [21, in German] or [65]). It will show which kind of electronic systems can be found in present and near-future cars, classify these systems from an electromagnetic compatibility (EMC) perspective into functional domains and show their properties concerning EMC and functional safety. In particular, it shows how electronic control units, power supply, communication and connections to sensors and actors work. This chapter is also a good frame for a short introduction to drive-by-wire technologies, the communication of the car with other cars (Car2Car, Car2C), the road side infrastructure (Car2I) or both (Car2X) and for autonomous driving.
-
2 Electrical drives and charging infrastructure
- + Show details - Hide details
-
p.
43
–57
(15)
Most cars these days are driven by an internal combustion engine (ICE) (diesel or gasoline). This is going to change, with the goal to reduce greenhouse gas emissions and noxious pollutants such as particulate or nitrogen oxides. On the one hand, an ICE can be combined with electric motors (hybrid car), and on the other hand, a car can run completely on electric power (electric car). It is possible to have one electric motor or to fit each wheel with its own electric motor, preferably in the hub. Hybrid technology sometimes is considered a transitory technology towards completely electric power trains [194].
-
3 Fundamentals of functional safety
- + Show details - Hide details
-
p.
59
–101
(43)
Although we live much safer than our uncivilised ancestors, technical products carry new risks into our lives. There would be no progress without taking risks, but risks must be limited to a tolerable order of magnitude. At first sight, it might look cynic to compare risks to human lives with costs to prevent them or to quantify these risks by true or ideal costs; indeed, it is not an easy job to find the legally and ethically right way. Laws depend on the country, and there are cultural differences in ethical considerations. In this chapter, we will learn the basic ideas about functional safety, we will get to know important standards such as ISO 26262 [132] ... [141] and see how much this topic is related to EMC under any possible working conditions. Functional safety is an issue comprising hardware and software, so it is worth to have a look also at software-related practices in order to see if we can learn something for hardware development and in particular for EMC. It should be mentioned that systems profit from simplicity, so increasing complexity of systems tends to impair EMC and functional safety. Besides product complexity, a development which is increasingly distributed over several departments or companies is a challenge. We will see that a systematic approach to functional safety can also improve product quality.
-
4 Fundamentals of EMC, signal and power integrity
- + Show details - Hide details
-
p.
103
–127
(25)
In this chapter, some EMC basics are explained - in particular, how interferences couple from their sources along wires or via fields to the victims (sinks), where and how they are generated, how victims are influenced by electromagnetic interference (EMI) and how countermeasures generally work; special countermeasures are discussed in later chapters. For a deeper understanding, textbooks dedicated to the fundamentals of EMC or even electrodynamics are recommended, e.g. [64] from a theoretical perspective, [10,19,203] from a mathematical/numerical perspective and [174,188] from a practical perspective. Together with EMC, signal integrity and power integrity (SIPI) are also considered. It is important to consider EMC early in the development process. We will pick up the design flow with EMC management, EMC analysis and EMC control in subsequent chapters - in particular, Chapters 6 and 7. We lay foundations for simulation in
-
5 Legal framework
- + Show details - Hide details
-
p.
129
–145
(17)
Basically a car manufacturer has a free choice to offer what the market requests or what he thinks to be good for market. However, there are some areas which are more or less strictly regulated all over the world by law or subsequent jurisdiction - in particular emissions, theft protection, vision and signalling, EMC and product safety, including functional safety. Those are the criteria which only contribute weakly to distinguish the own brand from the competitors, but law fulfilment is necessary, although some countries fail to supervise compliance with laws. If cars or components are sold in different markets, knowledge of all relevant laws and their interpretations is indispensable. In contrast to laws, technical standards are not directly compulsory, but many laws refer to certain standards, and, in a lawsuit, a good reason is necessary for why the state of technology as defined by standards has not been implemented. So standards get indirectly compulsory.
-
6 EMC design on ECU level
- + Show details - Hide details
-
p.
147
–162
(16)
In the different domains, as shown in Chapter 1, there are different types of electronic control units (ECUs). Many automotive ECUs differ from non-automotive equipment in the requirements (environment, reliability) and realisation details. Besides general advice on EMC design, these particular problems of automotive ECUs are highlighted in this chapter.
-
7 EMC design on system level and in special subsystems
- + Show details - Hide details
-
p.
163
–169
(7)
It is insufficient to conclude system EMC from the EMC of the components. Now we consider each electronic control unit (ECU) as a black box and have a look at the EMC of the whole car or several subsystems with typically more than one ECU, sensors, actors and connections for power and communication.
-
8 Modelling and simulation
- + Show details - Hide details
-
p.
171
–181
(11)
During product development, measurements are expensive due to personal effort or restricted resources such as semi-anechoic chambers. It is straightforward to put this workload into a computer which simulates the measurement setup or even the road reality. It should not be forgotten that a trustworthy simulation needs a model which also requires some effort. Finally, the model needs to be validated which is typically done by measurement. So for a single use, modelling may get more expensive than a direct measurement, but models can be reused in later project phases or for other projects. They can also help to get a deeper understanding. Even a good model stays a model which differs from reality, so a complete substitution of measurements and tests, in particular for compliance, is not realistic. The belief that simulation avoids costs of equipment might be disturbed in some cases by license fees for software. There is a lot of free software around which often uses the same algorithms as commercial packages, but in some cases, commercial products are more comfortable to use and faster to learn. Some packages conceal their algorithms so far, that it is hard to understand in detail how a result has been calculated. Sometimes, the source code of free software is open, in particular for academic use the possibility of modification might be interesting.
-
9 Test and measurement
- + Show details - Hide details
-
p.
183
–211
(29)
The purpose of a test is to discover faults of a product. Sometimes people say the contrary, i.e. to confirm that everything is hopefully alright. As a young engineer in automotive industry, once I have enthusiastically discovered a crucial problem in a test. The project manager was not amused and asked to repeat the test. Varying the test conditions slightly, I finally succeeded not to reproduce the fault any longer. Everybody was glad to keep the schedule, but the fault remained unfixed. Only a test showing as many faults as possible will be worth its costs. In order to avoid bad surprises close to delivery, it is reasonable to test during and after the design of a product. Early tests during development are often done in a less-systematic manner relying on the experience of the tester. Later tests approach requirements by standards and laws (precompliance). In the latest steps, compliance tests are done. In contrary to previous tests, now it is truly the goal of a manufacturer to demonstrate the fulfilment of standards and laws (and the goal of society and legislation referring to standards to keep immature or even unsafe products away from customers). This chapter will show equipment and methods for research and development in early stages as well as precompliance and compliance to common standards.
-
Back Matter
- + Show details - Hide details
-
p.
(1)