Use of the DC power analyzer to simulate transients in vehicle charging systems can provide significant benefits to the automotive R&D engineer. To begin with, because the solution boasts functionality similar to that of multiple discrete solutions, it offers a much quicker time to measurements at a lower cost. The time consuming, cumbersome and complex process of setting up and programming these multiple discrete solutions (e.g., current probes and shunts) is completely eliminated. In fact, the DC power analyzer's design makes it ideal for use in design validation, where ease of setup and ease of use are paramount.

Another key benefit that results from eliminating the need for multiple instruments, concerns developing and debugging the programs that control those instruments. Traditionally, when executing complex tasks requiring the simultaneous connection to and physical interaction with multiple test instruments, the risk of error increases. R&D engineers may choose to automate tests that are too complex to do manually. But while automating tasks reduces human error, writing and debugging programs adds more work to already overloaded R&D engineers. The DC power analyzer eliminates the need to develop and debug programs altogether. All the functions and measurements are available at the front panel and there is no longer a need for a PC, drivers and software. As a result, the R&D engineer can realize a significant reduction in the effort associated with setup.

As an added benefit, the DC power analyzer allows the user to playback captured waveforms by importing the data from a “.CVS” file into a user-defined waveform — a feature crucial to ensuring accurate testing for power system transients. Ideally, testing of an ECU would occur in the vehicle itself, under all operating conditions. Since this is not practical, the next best thing is to capture or record the voltage transients as they occur in the vehicle and then play them back later in the development lab to test the ECU. To capture the transients, the engineer simply connects an oscilloscope to the power system where the ECU will be located and then exercises conditions known for generating transients, such as engine cranking, compressor activation and cold temperature operation. Note that the N6705A scope referenced in the above example cannot be used to capture this waveform because it can only measure the power that it sources (e.g., the power that comes out of it). Any resulting power system transients are captured as shown in Figure 4 and the information is then downloaded to the DC power analyzer for replication using the built-in arbitrary waveform capability.

Simulating vehicle charging system power waveforms for R&D testing of electrical components is a critical, and yet costly and difficult task. Use of a new category of measurement instrument — the DC power analyzer — can greatly simplify this task by providing functionality similar to that of multiple instruments in a convenient benchtop solution. Along with arbitrary waveform control, slew rate control and flexibility, this capability provides today's automotive R&D engineers with a quick, efficient and cost-effective means of gaining insight into potential problems in vehicle charging systems.

Al Lesko is an applications engineer with Agilent Technologies' System Products Division. Lesko began his career at Hewlett-Packard/Agilent in 1980, where he worked as a manufacturing engineer on various instrumentation products. In 1989, Lesko joined the Ford Motor Company to work on anti-lock brake systems as an R&D design engineer. In 1993, he returned to H-P/Agilent to work on various automotive-related systems. He was the lead hardware architect on the TS-5400 SII VXI-based automotive test system and in 2006 became an applications engineer for Agilent Technologies' System Products Division.