Testing Challenges in Motor Drive Systems (Part II)

Figure 1: This image depicts the complete design and
debug challenge posed by a variable-frequency motor drive

In our first post on motor drive systems, we broke down the major subsystems in a "generic" variable frequency drive (VFD) and discussed some of the test requirements in those subsystems (Figure 1). Next, let's have a look at some of the variations in real-world VFDs in terms of architectures and topologies.

Testing Challenges in Motor Drive Systems

Figure 1: The power section of a motor drive system requires
measurements of line input, PWM output, and efficiencies

Motors are everywhere in our world, and nowhere more so than in  our vehicles. For example, when's the last time you had to crank a car window up and down to pay a highway toll? Or, for that matter, when did you last manually adjust the seat position or rear-view mirror angles? These aspects of vehicles are all typically motorized these days.

The History of Jitter (Part III)

Figure 1: Latching a signal at the outermost of the blue

hash marks results in a BER of 10^-3, while latching it

at the innermost hash marks yields a BER of 10^-12

If you've been keeping track of our history of jitter, we left off in Part II in the late 1990s, by which time bit-error rates (BER) had become a predominant statistic for quantifying jitter. That was subsequently refined into thinking in terms of BER as a function of jitter.