Validation of the HV electrical system involves very high requirements for sampling rate, HV safety and scalability of the measurement system used. The entire HV electrical system is instrumented and sampled at numerous points to assure that all HV system components perform their tasks and are operational in any conceivable driving situation.
These measurements must be made at very high sampling rates to acquire and quantify additional effects such as voltage peaks caused by line inductances, abrupt load alternation or capacitive coupling of fast switching processes in the power electronics. To analyze the causes of errors, all of these measurements must be time-synchronous and must not originate from different measurement systems that are not coupled. The ECUs in the vehicle, besides transmitting measurement parameters on the various vehicle buses, also provide information that is relevant and important for validation. That is why this information is also measured time-synchronously and needs to be incorporated into the evaluation of overall behavior.
Of course, the measuring instruments used must be suitable for HV to prevent any sorts of hazards to users in the service garage or in vehicle operation. Validation conducted under extreme driving and operating conditions ensures that the specific design of the HV electrical system in the vehicle has sufficient reserves without imposing any limitations on vehicle operation. The road tests conducted for this purpose can also examine the effects of two electric motors with superimposed interferences.
Since voltage peaks are very fast and sporadic, and the tester needs this precise information during the drive, the measurement software must meet an additional, special requirement. It must be able to evaluate the signals online, e.g., to calculate triggers for starting recording. The trigger condition might, for example, be derived from the voltage signal over time, to detect whether a maximum value is exceeded in fast voltage changes.
The measurement system must, of course, be able to record all data (HV signals, ECU measuring signals and calculated signals) for later detailed analysis or for documentation purposes.