PWM Technique:
- Pulse Width Modulation (PWM) is a control technique used in power electronics converter to regulate power supplied from power source to load.
- It is a technique used in inverter to create an ac waveform by controlling the electronic switch to produce varying width pulses.
- Minimize power frequency, harmonic distortion in some application, but care must be taken to properly filter out the switching frequency which are commonly 3 to 6 KHz.
CBEMA curve:
- CBEMA stands for Computer Business Equipment Manufacturers Association.
- It is one of the most frequently employed display of data to represent the power quality.
- The curve is originally developed by CBEMA to describe the magnitude and duration of voltage variation on the power supply that Mainframe computer equipment can tolerate.
- This curve is used as a standard for measuring/comparing the performance of all types of equipment.
- Few data of for the curve was also taken from IEEE standard.
ITI Curve:
- ITI stands for Information Technology Industry council.
- The ITI replaced the CBEMA organization and a modified curve has been developed.
- This curve is specifically applicable to common 12V computer equipment.
- The concept used in ITI is similar to that of CBEMA curve.
- The curve has been applied to development of power quality evaluation.
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