Patent ID: 7099165
Filing Date: 2006-08-29
Classification: H02J,H02M,Y02E

Abstract:
1. For a power conversion system that converts alternating current (AC) power on an AC bus to DC power, a harmonic scrubber that reduces ripple currents for selected harmonics on the AC bus due to nonlinear loads on the AC bus, comprising: at least one phase-locked loop (PLL) coupled to each phase of the AC bus for producing synchronisation signals for each of the selected harmonics on each phase of the AC bus; at least one synchronous filter coupled to each PLL for each of the selected harmonics for combining corresponding harmonic synchronisation signals with ripple signals that represent the potentials of the ripple currents to produce harmonic compensation control signals for each of the selected harmonics that are equal in amplitude and opposite in phase to the potentials of the ripple currents on each phase of the AC bus; at least one pulse width modulator (PWM) for generating PWM drive signals for each phase of the AC bus in response to the harmonic compensation control signals; and at least one active filter coupled to each phase of the AC bus responsive to the PWM drive signals to reduce the harmonic ripple currents on each phase of the AC bus.