Rebonjour
Terminologie.....
How do you define "active rectifier", to me it's a mains frequency AC rectifier with transistors instead of diodes for higher effecincy in very low V output supplies, where a diode drop 0.6 Vf causes significant losses.
Perhaps your terminology differs?
Class E....
Our old friend and colleague Dr Nathan SOKAL (RIP) invented Class E and patented it decades ago.
He received an IEEE award.
The class E topologies have advantages in certain applications, and depending upon the switch frequency either BJT FET GaN or SiC devices can work. But GaN is relatively expensive and may have availability issues compared to the others.
If your objective is to learn about Class E or GaN, bravo!
But for practical designs, cost, availability, magnetics, efficiency dictate a logical engineering approach.
We advocate considering all topologies, devices types, switch frequency etc. and choosing the right compromise topologies, switching devices and frequency.
Just the ramblings of an old retired EE
Jon