I know this does not meat specification but:
dynamo, 4 diodes, large cap=C9 which should be very large for 10hz but I found that 4700uF does work. (small in the picture for testing)
IC= LT8631 Vin<100 volts. I out=1.5A max.
The "PG" pin (Power Good) "PG2" tells the rest of the board that the output is good. +5V.
Here is the boost supply. It takes +5V and charges the super cap to 28.8 volts.
Note: The first boost supplies I tried pulled too much from the +5V and killed the supply. This IC is set to input current limit at 300mA to solve this problam. It only works when the first IC indicates the power is good. The boost shuts down when the input AC power stops.
The last IC bucks 30V down to +5V at 1Amax. Q1 turns it on/off from "PG2"
Note the two +5V buck supplies are connected together with out "switches" or diodes. PG decides which one will be on & off.
I know this will not work for you but I thought I would try something and see what happens.
Points to watch for:
* The boost supply must be input current limited so it will not eat up all the power.
* Two buck supplies can drive the same load.
* At 10hz (normally there must be a very large cap. But; it is OK for the buck to work only during the peaks of the AC and them the super cap will power the load during the valley of the AC.
* For the purpose of testing; reduce the value of the super cap and input cap so you don't have to wait for hours for spice to work. (a smaller super cap will charge faster for testing)
* Did not use any "active diodes" because they are very hard to make.
* Input buck supply set to stop working below 6V (about) to reduce load on the AC input. This gives the dynamo a chance to get up and running.
* There is no input current limiting. (500mA) That can be added. (not easy)
* The input 4 diodes could be high voltage Schottky diodes. (200 volts)
* Diode D7 is important. SPICE does not show this! Stops L3 saturation during startup.
Hope there are some ideas you can use.
Ron Simpson