Power electronics impact our lives in many ways - from new power circuits that extend battery life to voltage regulators that help manage and distribute energy more efficiently from the grid to the consumer. This five-part power fundamentals course covers an overview of power electronics, components, topologies and control theory.

Beware of using the nameplate. This is a legality rating and will usually give a much higher volt-ampere rating than the unit will ever draw. For example, consider a unit with a nameplate that reads 90 to 240 volts at 4 to 8 amps with a 500 W power supply. In the nameplate reading, the numbers are backward. The larger amperage goes with the lower voltage. If you assume a nominal 120 volts at 8 amps, you get 960 VA. A PF of 0.95 would yield 912 W. No power supply is that inefficient, and a power supply almost never runs at full power. Therefore, it is highly unlikely that this device will ever draw more than 500 W of power, but if you want to be really conservative, multiply by 1.1 and figure 550 W of input power.




Fundamentals Of Power Supply Design Robert A. 32