Power Education

TI is unleashing the power of silicon carbide with a new, verified reference design that provides an overview on how to implement a three-level, three-phase SiC based DC:AC grid-tie inverter stage. In this video you will learn the advantages of a three-level topology; what TI technology is driving the SiC MOSFETs;  how and where are we sensing V & I; what is behind the digital power controller; and what efficiency and power density levels you can achieve with this design. Tune in as TI discusses this innovative technology at the Applied Power Electronics Conference.

Suppose a 12 volt lead-acid battery has an internal resistance of 20 milli-ohms (20 mΩ): If a short-circuit were placed across the terminals of this large battery, the fault current would be quite large: 600 amps! Now suppose three of these batteries were connected directly in parallel with one another: Reduce this network of parallel-connected batteries into either a Thévenin or a Norton equivalent circuit, and then re-calculate the fault current available at

So far we know that AC voltage alternates in polarity and AC current alternates in direction. We also know that AC can alternate in a variety of different ways, and by tracing the alternation over time we can plot it as a “waveform.” We can measure the rate of alternation by measuring the time it takes for a wave to evolve before it repeats itself (the “period”), and express this

Don’t just sit there! Build something!! Learning to mathematically analyze circuits requires much study and practice. Typically, students practice by working through lots of sample problems and checking their answers against those provided by the textbook or the instructor. While this is good, there is a much better way. You will learn much more by actually building and analyzing real circuits, letting your test equipment provide the “answers” instead

Because batteries create current flow in a circuit by exchanging electrons in ionic chemical reactions, and there is a limited number of molecules in any charged battery available to react, there must be a limited amount of total charge that any battery can motivate through a circuit before its energy reserves are exhausted. Battery capacity could be measured in terms of a total number of electrons, but this would be

AC Motors Perhaps the most important benefit of polyphase AC power over single-phase is the design and operation of AC motors. As we studied in the first chapter of this book, some types of AC motors are virtually identical in construction to their alternator (generator) counterparts, consisting of stationary wire windings and a rotating magnet assembly. (Other AC motor designs are not quite this simple, but we will leave those

Example Derivatives of e Proportionality Constant When we say that a relationship or phenomenon is “exponential,” we are implying that some quantity—electric current, profits, population—increases more rapidly as the quantity grows. In other words, the rate of change with respect to a given variable is proportional to the value of that variable. This means that the derivative of an exponential function is equal to the original exponential function

This calculator shows the peak-to-peak voltage (VP-P) value from the peak voltage, RMS voltage, or average voltage.

Don’t just sit there! Build something!! Learning to mathematically analyze circuits requires much study and practice. Typically, students practice by working through lots of sample problems and checking their answers against those provided by the textbook or the instructor. While this is good, there is a much better way. You will learn much more by actually building and analyzing real circuits, letting your test equipment provide the “answers” instead

In this experiment, we will aim to learn about the following concepts: • Capacitor charging action • Capacitor discharging action • Time constant calculation • Series and parallel capacitance Capacitor Charging and Discharging Experiment Parts and Materials To do this experiment, you will need the following: • 6-volt battery • Two large electrolytic capacitors, 1000 µF minimum (Radio Shack catalog # 272-1019, 272-1032, or equivalent) • Two 1 kΩ resistors • One toggle switch, SPST (“Single-Pole, Single-Throw”) Large-value capacitors are required

The first, and perhaps most important, the relationship between current, voltage, and resistance is called Ohm’s Law, discovered by Georg Simon Ohm and published in his 1827 paper, The Galvanic Circuit Investigated Mathematically. Voltage, Current, and Resistance An electric circuit is formed when a conductive path is created to allow electric charge to continuously move. This continuous movement of electric charge through the conductors of a circuit is called a

PARTS AND MATERIALS Two 6-volt batteries One 9-volt battery Actually, any size batteries will suffice for this experiment, but it is recommended to have at least two different voltages available to make it more interesting. CROSS-REFERENCES Lessons In Electric Circuits, Volume 1, chapter 5: “Series and Parallel Circuits” Lessons In Electric Circuits, Volume 1, chapter 11: “Batteries and Power Systems” LEARNING OBJECTIVES How to connect batteries to obtain different voltage levels SCHEMATIC DIAGRAM ILLUSTRATION

Calculate the voltage output by the secondary winding of a transformer if the primary voltage is 35 volts, the secondary winding has 4500 turns, and the primary winding has 355 turns. Vsecondary =

Explain the difference between a balanced polyphase system and an unbalanced polyphase system. What conditions typically cause a polyphase system to become unbalanced?

Since three-phase is used so often for power distribution systems, it makes sense that we would need three-phase transformers to be able to step voltages up or down. This is only partially true, as regular single-phase transformers can be ganged together to transform power between two three-phase systems in a variety of configurations, eliminating the requirement for a special three-phase transformer. However, special three-phase transformers are built for those tasks

We're in section 9.2, Power Supply Applications. The reason we're looking at power supplies is because they are a major use of diodes. Nearly all computers have some sort of power supplies. Now a power supply circuit must do several things. One of them is to convert AC line voltage into a DC voltage required by the circuit. They also must reduce the AC voltage to a lower value and they

PARTS AND MATERIALS Four 6 volt batteries One capacitor, 100 µF electrolytic, 35 WVDC (Radio Shack catalog # 272-1028 or equivalent) One capacitor, 0.1 µF, non-polarized (Radio Shack catalog # 272-135) One 555 timer IC (Radio Shack catalog # 276-1723) Dual operational amplifier, model 1458 recommended (Radio Shack catalog # 276-038) One NPN power transistor—(Radio Shack catalog # 276-2041 or equivalent) Three 1N4001 rectifying diodes (Radio Shack catalog # 276-1101) One 10 kΩ potentiometer, linear taper (Radio Shack catalog # 271-1715) One 33 kΩ

Wiring for AC and DC power distribution branch circuits are color coded for identification of individual wires. In some jurisdictions all wire colors are specified in legal documents. In other jurisdictions, only a few conductor colors are so codified. In that case, local custom dictates the “optional” wire colors. IEC, AC: Most of Europe abides by IEC (International Electrotechnical Commission) wiring color codes for AC branch circuits. These are listed

PARTS AND MATERIALS Steel flat bar, 4 pieces Miscellaneous bolts, nuts, washers 28 gauge “magnet” wire Low-voltage AC power supply “Magnet wire” is small-gauge wire insulated with a thin enamel coating. It is intended to be used to make electromagnets, because many “turns” of wire may be wrapped in a relatively small-diameter coil. Any gauge of wire will work, but 28 gauge is recommended so as to make a coil with as many

Inductive reactance Capacitive reactance Impedance in relation to R and X ZL = R + jXL ZC = R - jXC Ohm’s Law for AC Series and Parallel Impedances NOTE: All impedances must be calculated in complex number form for these equations to work. Resonance NOTE: This equation applies to a non-resistive LC circuit. In circuits containing resistance as well as inductance and capacitance, this equation applies only to series configurations and

In instrumentation circuitry, DC signals are often used as analog representations of physical measurements such as temperature, pressure, flow, weight, and motion. Most commonly, DC current signals are used in preference to DC voltage signals, because current signals are exactly equal in magnitude throughout the series circuit loop carrying current from the source (measuring device) to the load (indicator, recorder, or controller), whereas voltage signals in a parallel circuit may