The Power Handbook

Preface  

Those of you familiar with Keysight’s previous power supply handbook (application note 90B) will find quite a few changes in this updated version. Whereas the old handbook focused extensively on issues around power supply circuits and design, this handbook focuses more on how to effectively use power supplies and electronic loads to achieve specific application goals. The intent of this handbook is to provide a “one-stop-shop” for basic information on power-related topics, and it incorporates information from many of our application notes. We hope that you find this handbook a useful tool that allows you to get the maximum benefit from our power-focused products. 

Table of Contents 

Chapter 1 – Power supply evolution 

Chapter 2 -  Electric power fundamentals 

Chapter 3 - DC power supplies 

• Linear vs. Switching Power Supplies 
• Common Mode Current Noise 
• Keysight’s Ultra-Low Noise Sources 
• Rectangular output characteristic 
• Over Voltage Protection (OVP) 
• Generating arbitrary waveforms 
• What is a two-quadrant power supply? 
• What is a regenerative supply? 
• Source/Measure Units (SMUs) 

Chapter 4-  Electronic Load 

• What are some typical E-load applications? 
• DC Electronic Load Operation Modes 
• The Effect of FETs on Load Behavior 
• Combining Loads in Parallel 
• Over-power protection (OPP) 

Chapter 5- Battery 

• Battery Electrical Ratings 
• Battery Profiling and Emulation 
• Measuring Battery Resistance versus State-of-Charge 
• Standard Battery Test Procedures 
• Battery Testing with Electronic Loads 

Chapter 6- Power Conversion 

• Testing DC to DC converter load regulation 
• DC to AC conversion: Power Transistor Testing 

Chapter 7- Photovoltaic Power 

• Factors affecting solar cell output 
• Ground Testing of Solar Arrays for Satellites 
• Solar array considerations for satellites 
• Keysight Solar Array Simulator Solutions 

Chapter 8- Power Supply Software 

• What is an instrument driver? 
• What is Command Expert? 

Glossary: Power Supply & Instrument Control Terminology 

Appendix 

 Appendix  Basic Power Supplies  

• E36100 Series of Basic DC Power Supplies  
• E36300 Series of Triple Output Bench Supplies  
• N8900 Series of 5, 10 and 15 kW Auto-Ranging DC Supplies  

Appendix Advanced Power Supplies  

• N6900/N7900 Advanced Power System DC Supplies  
• RP7900 Series of Regenerative Power Systems  

 Appendix Electronic Loads  

• N3300 Series Modular DC Electronic Load 

Appendix Benchtop Power Analysis

• N6705C DC Power Analyzer 

Appendix AC Power Sourcing and Analysis  

• PA2200 IntegraVision Power Analyzers

Why use a load rather than a resistor?  

An electronic load offers higher flexibility than a simple resistor by allowing you to sink various levels of power profiles in multiple modes. The most common operating modes of an electronic load are constant current (CC), constant voltage (CV), constant resistance (CR), and constant power (CP). An electronic load is an effective solution to test devices rather than using a fixed value resistor. A fixed resistor makes it difficult to automate and emulate the dynamic behavior of a real device. It also makes it difficult to adapt to changes in test requirements 

What are some typical E-load applications?  

The following are typical applications showing the use of electronic loads across various industries. 

• Power converter and inverter testing 
• Uninterruptible power supply (UPS) 
• Batteries and fuel cells 
• Solar panels 
• Portable devices 

Can programmable power supplies simulate solar arrays?  

Before proceeding further, a reasonable question to ask is: Why do you a need specialized instrument to simulate a solar array when standard programmable power supplies should be able to do the same function? There are actually three good reasons why a solar array simulator (SAS) is the best choice for this application, and they are all explained below.  

The first reason that programmable power supplies are not optimal for solar array simulation has to do with output capacitance. Designers of general-purpose power supplies want them to act as voltage sources that maintain a stable output under a variety of load conditions. While this behavior is ideal for a wide range of applications, it is not so good for solar array simulation. The reason is that solar panels are current sources, so their design needs to include the ability to operate as a current source. Current sources typically have high output impedance and low output capacitance, and these characteristics provide two benefits:  

1. Fast switching speeds for better simulations and shorter test times  
2. Enhanced protection of the DUT by reducing the power stored in the circuit (smaller short-circuit current spikes)  

The second reason that programmable power supplies are not optimal for solar array simulation has to do with output flexibility. Conventional rectangular power supplies (see Chapter 4) adjust the output voltage and current across straight line values, whereas solar array panels have exponential-shaped IV curves. Therefore, to truly emulate solar array behavior SAS must be capable of making similarly shaped curves. In addition, an SAS also has to be capable of making rapid curve changes to realistically simulate varying irradiation levels, changes in temperature, as well as the effects of spin, eclipse, and shadow.  

The third and final reason that programmable power supplies are not suitable for solar array simulation has to do with their ability to protect DUTs from damage. Since satellites are delicate (and expensive) instruments that voltage and current spikes can easily damage, instruments used during their ground testing must provide extensive levels of protection. The typical over-voltage protection (OVP) and over-current protection (OCP) circuits found in conventional power supplies are not sufficient to guarantee sensitive satellite circuitry will not experience transient current spikes or protect internal components from harmful power levels.