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Three-level voltage-source inverter for shunt active Filter
Abstract
An active power filter or power-line conditioner is an important way to compensate reactive
power and suppress harmonics drawn from nonlinear loads. A single-phase active filter is
presented to operate as a controlled current source to compensate the load harmonics and
generate a sinusoidal line current from the AC source. The adopted single-phase voltagesource inverter is based on four active switches and two capacitors to achieve three-level
pulsewidth modulation. The circuit topology of the adopted inverter has fewer power
semiconductors compared with the single-phase neutral-point-clamped inverter and flying
capacitor inverter. To maintain the DC-link voltage constant and compensate the power
losses of inverter, a proportional-integral voltage controller is used in the outer control loop.
A carrier-based current controller is adopted in the inner control loop to track the line current
command in phase with the mains voltage. The effectiveness of the proposed control
algorithm is verified by computer simulation and experimental results.