Hello,

the paper available via the following link might shed light on this (though the generation of the control signal itself is not shown, but to some extend described in the text): https://www.researchgate.net/publication/252000475_The_synchronized_switch_harvesting_circuit_on_inductor_based_on_piezoelectricity

Hope this helps

Article The synchronized switch harvesting circuit on inductor based...

There is an electronic switch before the bridge rectifier. For AC switching should be used TRIAC not MOSFET or transistor (DC switching). 

I'm not sure whether to take your answer positive or negative... so let me add 2 things;

Regards

Here is the schematic circuit that mention needed an electronic switch before the bridge rectifier.

Then: back to the start!

The complementary MOSFETs switch does this job without requiring too much power to activate it.

Thanks U. Dreher, I will try to test it~ Appreciate your help.