ACTIVE POWER OF ELECTRICAL CIRCUIT ANALYSIS
ACTIVE POWER :
An ” Active Power Factor Corrector” ( active PFC) is a power electronic system that changes the waveshape of current drawn by a load to improve the power factor. The main purpose is to make the load circuitry that is power factor corrected appear purely resistive ( apparent power equal to real power). In this case, both voltage and current are in phase and the reactive power consumption is zero. This enables the successful efficient delivery of electrical power from the power company to the consumer.
Active power factor corrector used can be single-stage or multi-stage.
In the case of a switched-mode power power supply,a boost converter is inserted between the bridge rectifier and the main input capacitors.The boost converter also attempts to maintain a constant DC bus voltage on its output while drawing a current that is always in phase with and at the same frequency as the line voltage.Another switch mode convert inside the power supply produces the desired output voltage from the DC bus.This approach requires additional semiconductor switches and control electronics,but permits the cheaper and smaller passive components.It is frequently used in practice.For example,SMPS with passive PFC can achieve power factor of about 0.7-0.75,SMPS with ,up to 0.99 power factor and while a SMPS without any power factor correction has a power factor of about 0.55-0.65 aproximately.
SOME EXPECTED QUESTIONS BASED UPON ACTIVE POWER OF DIGITAL CIRCUIT ANALYSIS ARE:
QUES 1) What is meant by active and reactive power?
ans- KVA consists of recative power.
active power consists of watts. ACTIVE POWER is the actual useful power. reactive power means inductive power which increases means we have to improve power factor for balancing the system