Anomalous Solar activity in the weak 20th and 23rd cycles as a manifestation of the 11-year cycle invariance

«Anomalous» solar activity in 1972, 2003, 2004 can be explained by the delay in transient oscillation process of polarity reversal of the Sun's total magnetic field in the weak 20th and 23rd cycles. This is associated with the manifestation of the invariant «amplitude-duration»; i.e., with constancy of the area, enclosed by the 11-year-cycle curve. This invariant indicates that the 11-year cycle is soliton-like (the envelope soliton). Constancy of the energy, released in a single cycle, implies that the 11-year cyclicity is the self-oscillating mechanism of solar temperature regulation. The annual variation contribution is significant in the minimum of odd 11-year cycles with a negative sign of the Sun's total magnetic field. This can be observed in the minimum of the current 23rd solar cycle in 2005-2007.