22-06-2012, 02:46 PM
PROJECT ON ACTIVE POWER FILTER
ACTIVE POWER FILTER.pptx (Size: 513.52 KB / Downloads: 45)
Active Power Filter
Active power filters play an important role in reducing harmonic contamination in power
Lines.Active filters have the capability to compensate randomly varying currents.One of
the most popular active power filters is the “Shunt Active Power Filter,”.A current source,
Connected in parallel with the nonlinear load,is controlled to generate the required
harmonic current
Functions of Active Filters
1. Reduction of the current THD
2.Reduction of the harmonic current content
3.Compensation of reactive power and an improvement of the power factor cos ø
4. Display of mains current and voltage
5.Load balancing
Shunt Hybrid Active Power Filter
Hybrid filter
Combination of active and passive filters
Active and passive filters have drawbacks
The purpose of the hybrid filters is to overcome these problems that are characteristic of the individual filter type
Parallel interleaved inverters for Shunt Active Power Filter
A common solution for harmonic compensation in large
industrial plants is to mitigate the harmonic currents at the
point of common coupling (PCC), by using either passive or
active methods . As a passive method may create problems
with uncontrolled resonances between the capacitor and the
existent source impedance , a more efficient way is by
using active filtering methods.
Paralleling multiple inverters makes the design,
production, installation and maintenance much simpler and
flexible. Also it is easier to extend the total rated power of an
active power filter (APF) by simply adding a new module.
Active Power Filter Based on Multi-stage Inverter
Each stage of the filter uses the pulsewidth
modulation (PWM) method. The results confirmed high efficiency of such a compensating circuit. Multi-phase systems will be considered as design alternatives during the variant
design of electric power supply systems. Increasing the number of phases in the electric power supply system, p, leads to multiple increase of the number of bridge elements,
found in active power filters which are based on multi-stage inverter architecture.
Five-Level Cascaded Active Filter for Power Line Conditioners
Recently Active Power Line Conditioners (APLC) or Active Power Filters (APF) overcome
these problems and are used for compensating the current-harmonics and suppressing
the reactive power simultaneously due to fluctuating loads .