Impact of Multi-Cycle Symmetrical Control on Power System

Roger Bergeron

Multi-Cycle symmetrical control (MCSC) for application above 1.2 kW fails compliance tests once IEC 61000-4-7 edition 2 introduced a new assessment method which groups inter-harmonic into the harmonic levels. MCSC-driven apparatus up to 3 kW may succeed the compliance test if IEC 61000-4-7 neglects interharmonic components at frequencies below the second harmonic order. Upon the power level, MCSC-driven apparatus could disturb the ripple-control system needed for communication. Probabilities of disturbance at 116, 183 and 216 Hz with MCSC applications above 1.2 kW exceed the 5% EMC rule particularly for power rating nears to 3 kW.