The invention provides compounds of the formulawherein the substituents are as defined in the application. While the first switch is closed, the SEPIC portion is configured to store energy from an energy source in at least some of the first set of passive components and deliver energy to the BUCK portion, and the BUCK converter portion is configured to deliver energy to a load and to store energy in at least some of the second set of passive components. The engine, the first motorgenerator, the second motorgenerator and the first axle are each operatively connectable for rotation with a different member of the first and the second planetary gear sets. In various exemplary embodiments, the silicon optical switches comprise optical switches, micromachined torsion mirrors, electrostatic micromirrors, andor tilting micromirrors. In another aspect, a software program for accomplishing the method of the present invention is provided. The guide links assist in supporting the chain along the return run in a suspended fashion intermediate of the outer sides without causing wear on the conveying surface.