• ## The Effect of Phase on Switching Rectifiers

In the previous post, we examined some of the most basic switch based rectifying circuits and saw that the switch could be replaced with a passive diode. Here, we will […]

• ## Basic Power Conversion Examples

Let’s look at a few examples of power electronic systems. Consider the circuit shown below. It contains an AC source, a switch, and a resistive load. It is therefore a […]

• ## Inverters, Controlled Rectifiers, and the SCR

In many cases, the distinction between a rectifier and an inverter is artificial; In a rectifier, energy flows from an ac source to a dc load. In an inverter, the […]

• ## The Need for Electrical Conversion

In the 1880s, two major inventions determined the course of electric power systems. George Stanley built a practical transformer, and so allowed convenient conversion among various voltage levels for ac. […]

## The Significance of Fourier Analysis

The switch action in a conversion circuit is most often periodic. The waveforms themselves are rather choppy and sometimes discontinuous. We must form an approximate DC output of a rectifier, for instance, by piecing together ‘chunks’ of the AC input. Given the strange waveforms and the periodic action, how can we determine whether a conversion operation is successful? What filtering is […]

## The Switch Matrix

We already know that some switches will lie between an electrical source and a load. There might be just one switch, or perhaps a large group. In any case, there is a complexity limit. If a converter has m inputs and n outputs, even the densest possible collection of switches would have a single switch between each input line and each output […]

## Overview of Switching Devices

A switching function has a value of either 1 or 0; either a switch is on or it is off. When on, it will carry any amount of current for any length of time and in any direction. When off, it will never carry current, no mattery how much voltage is applied. This combination of conditions describes an ideal switch. […]

## Review of Fourier Series

Nearly any periodic function of time , such that , can be written as a sum of sinusoids known as the Fourier Series. where the radian frequency is defined as . This result applies to signals with jump discontinuities which are often encountered in the world of power electronics. While there are few very special periodic functions without Fourier Series […]

## Characteristics of Power Semiconductor Devices

Diode – Current ratings from under 1 A to more than 5000 A. Voltage ratings from 10 V to 10 kV or more. The fastest power devices switch in less than 20 nanoseconds, while the slowest require 100 microseconds or more. The function applies in rectifiers and DC-DC circuits. BJT – (Bipolar Junction Transistor) Conducts collector current (in one direction) when […]