Power Electronics and Energy

"Earth leakage currents arise mainly from the EMC filters built into electronic equipment with switched mode power supplies. Standards limit the leakage current from non-fixed equipment (i.e. equipment that plugs into a standard socket outlet) to less than 3.5 mA. When a lot of electronic equipment is in use, the total leakage current in the protective conductor can become significant."

Earthing Practice by Trevor Charlton

• Methods of Earthing
• Earth Conductors
• Electrical interference
• Lightning Protection

Power Quality and Utilisation Guide

The PQ E-library is a collection of electronic technical reference documents covering introduction, costs, harmonics, resilience, voltage disturbances, earthing, energy efficiency and renewables/distributed generation. See also - Power Quality

Copper Development Association

• Educational Resources
• Computers cannot work without copper
• Electricity in buildings

Copper Development Association Website for information on Copper and Copper Alloys

Copper Development Association - Resource Library

Copper Development Association provides a range of resources in support of the correct and efficient use of copper and copper alloys for major applications.

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I first saw this practically in the Orthodox Cherokee SMPS. This is where we differentiate from Engineered Products and just Mass Production without following standards. The Cherokee SMPS was a work of art, perfect in all respects.

The Copper Desert or Isolation Land

There is a No Man's Land in PCB. Any good power electronics designer should/will know. Product Safety and HV Isolation, Quality and Reliability all depend on this.

High Energy Circuits



These things don't come overnight, it is a culture, learning, experience and integrity of some of these American Firms. Reliability and Product safety are important. Every human values his life very much. A manufacturer too should appreciate this.

Coming back to isolation, Keep in mind creepage distance, High energy circuits and Low voltage circuits should have clear isolation, use the best insulation. Fire and shock hazard. Mains HV transitions, spikes.

Regulated High Voltage Power Supply

Power supply faces all these, even other areas where a Human Life or Property can be endangered.

HV High Voltage Reliability and Safety

Use a Servo Stabilizer or CVT Constant Voltage Transformer or at least an Isolation Transformer. The First Defense form HV Surges, Spikes.

High Voltage Polyester & Polypropylene Metallized Capacitors in Stepdown Supplies should be Fire Retardant & Self Healing with a MOV too.

Learn about Power flow, Sags, Dips, Phase rotation, Harmonics, Flicker and more!



Power Quality Teaching Toy

Standards

CBEMA - Computer Business Equipment Manufacturer's Association adopted curve IEEE Standard 446 (orange book) curve. Recommended Practice for Emergency and Standby power systems for Industrial and Commercial Application."


Main Points

• Wave form Sine wave THD (total harmonic distortion) maximum 5%.
• 3 Phase system phase imbalance of voltage 3% - 6%.
• Frequency stability 60  +/- 0.5Hz.
• Output Voltage +6% Max. -13% Min. from Nominal Value.
• Voltage can fall to 0V but should recover in 0.5 Cycles.
• On turn on Voltage should reach steady state within two seconds.
• Upto 200% over Nominal Voltage should be tolerated for 100uS. ( Transients, spikes and Inductive Kickbacks come in this)
• Upto 30% over Nominal Voltage should be tolerated for 0.5S.

ANSI - American National Standards Institute

"Standard Voltage Ratings for Electrical power systems & Equipment"

• Steady State Variations +/- 5% of Nominal Voltage. T
• Three Phase Voltage Imbalance 5% Max..
• Standard Frequency 60Hz.

Glossary

• Frequency 60Hz Hz is Hertz.
• One Cycle = 20mS (milliseconds) one full sine wave.
• Standard Frequency is 50Hz in many countries.
• Max - Maximum
• Min - Minimum
• uS - micro seconds, S - seconds.

Cause of Transients

1. Switching Loads Simultaneously (inductive loads).
2. Power factor correction capacitors and devices.
3. Lightning strikes (enhanced by earth faults).
4. Line Inductance (inductive kickback, resonance).
5. DC and AC Drives for Motors.
6. Rectifiers with large filters and stray inductance.

CBEMA Guideline
The CBEMA guideline, created by the Computer Business Equipment Manufacturers Association is a realistic, at-the-equipment, maximum allowable voltage that equipment can withstand, without damage or upset.

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 Here are two Sine wave Inverter circuit applications that can be made into an UPS or Uninterrupted Power Supply. These are used in Home, Office and Shops. It provides emergency power when Mains power goes down or browns out.



These also help supply power while switching from Mains Power to In-house Diesel Generation  Power Stations or Integrate with Solar Powered Systems to provide 110 Volts or 220 Volts AC.


800VA Pure Sine Wave Inverter - High Performance Isolated Power

This application note describes the design principles and the circuit operation of the 800VA pure Sine Wave Inverter.

800VA Pure Sine Wave Inverter's Reference Design, slaa602 - TI.com

The pure Sine Wave inverter has various applications because of its key advantages such as operation with very low harmonic distortion and clean power like utility-supplied electricity, reduction in audible and electrical noise in Fans, fluorescent lights and so on, faster, quieter and cooler running of Inductive loads like microwaves and motors.

Power inverter is a device that converts electrical power from DC form to AC form using electronic circuits. It is typical application is to convert battery voltage into conventional household AC voltage allowing you to use electronic devices when an AC power is not available. There are basically three kinds of Inverter out of which, the first set of inverters made, which are now obsolete, produced a Square Wave signal at the output.

Texas Instruments, Application Report SLAA602 , June 2013

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Here are project reports on how to manage the various design needs of a inverter for a power ups. Even Solar Energy systems need inverters to create AC Sine Wave Power Supply from a DC Battery Array.



Creating a Efficient and Inexpensive Inverter - By Jim Doucet, Dan Eggleston, Jeremy Shaw

This report focuses on DC to AC power inverters, which aim to efficiently transform a DC power source to a high voltage AC source, similar to power that would be available at an electrical wall outlet. Inverters are used for many applications, as in situations where low voltage DC sources such as batteries, solar panels or fuel cells must be converted so that devices can run off of AC power.


PWM Techniques: A Pure Sine Wave Inverter - Authors :Ian F. Crowley and Ho Fong Leung

This report documents the development of one component of an uninterruptible power supply, the DC-to-AC inverter. Through the use of analog signal processing techniques, a prototype which efficiently and accurately emulates the pure-sine wave power present on the power grid was created. The three-level PWM system within this report is created with the possibility of a feedback-regulated system to be implemented in the future.

MQP Terms A­B­C 2006 ­2007, Advisor: Professor Stephen J. Bitar

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