| 摘要 |
PROBLEM TO BE SOLVED: To provide a harmonic-current suppression apparatus through which a resonated lower-order harmonic current is suppressed by a method, wherein an active filter which is operated as an equivalent harmonic resistance only with reference to a resonated and expanded lower-order harmonic is installed at a system. SOLUTION: In an apparatus, a harmonic current which is generated from a load 1 is absorbed by an AC filter 4 which is connected across a power-supplu system Vs and the load 1, and a buffer reactor Lc which prevents the harmonic interference of a higher-order system with a lower-order system is inserted across the AC filter 4 and the power-supply system Vs. In this case, the apparatus is provided with an active filter 6 which is installed in parallel with the system Vs, in such a way that a PWM inverter 7 which is connected via a transformer T to both the ends of the buffer reactor Lc is provided. Then, a voltage whose phase is opposite to that of the harmonic current is generated via the transformer T from the inverter 7, the active filter 6 is operated as an equivalent resistance Re with reference to a harmonic current of a prescribed order, and the generation of resonance and the expansion of a lower-order harmonic current is prevented. |
