The interest in system level source and load impedance measurements is growing as we see more undesirable behavior in distributed power systems. There is significant growth in data centers and server farms, and such facilities have successive levels of power conversion as power is delivered to the servers or blades. Most of these systems are scalable, which can lead to combinations of source/load impedances that can result in power bus oscillations.
Venable has years of experience measuring output (source) and input (load) impedances and provide the knowledge and equipment to the industry to understand and solve the problem. In the white paper “Distributed Power- What Causes These Systems to Oscillate”, the reason for power bus oscillations is explained in detail. A summary of this phenomenon is described in the blog “Protect Your Distributed Power System from Oscillation”. Since there may be several levels of power conversion in a distributed power system, and in depth understanding of converter impedances is detailed in the white paper “Source-Load Interactions in Multi-Unit Power Systems”.
For details on how to make source and load impedance measurements, Venable has a three part series of blogs that detail the equipment needed, test set up, and procedures. The articles are found here:
Measuring the Input and Output Impedance of Power Supplies (Part 1)
Measuring Impedance of Power Supplies - Current Probe and Scale Factor (Part 2)
Measuring the Input and Output Impedance of Power Supplies (Part 3)
Additional impedance topics covered include:
M-CRPS Input Impedance Test Procedure Using a Venable FRA
Voltage Injection Scalability for High Current Impedance Measurements
With the knowledge and test equipment available from Venable Instruments, one can better understand and eliminate (better yet- prevent) undesirable, and possibly destructive, behavior in their data center and server farm power systems.