ac current limiting

I have a 120V 2400W generator and use it to charge a 60V battery. The problem is depending on the state of charge and its voltage the generator will over-load or under-load.
Right now I am using a variac into a rectifier to adjust the voltage and limit the 120V max current to 22A with low battery. But as the battery voltage increases the generator current drops and I am not using it's full capacity.
So I rigged up a small motor and a current-sensor which drives the variac up or down to stay at 22A. On start up of the generator the variac starts at 0 until the current goes over 22A. Shutting down the variac returns to 0. This actually works well except I have about 200W to 300W transformer losses and it is a mechanical contraption.
They make electronic dimmers, I could use the motor drive on that but there must be a more elegant solution.
Any ideas?

"Normally" one thinks of a charge controller for a battery that terminates in
a floating charge, for a lead acid battery. That would take the variac and its
mechanical control out of the picture.

You looking for off the shelf solution or a design to build ?

You can use a high-power buck converter with current control.

Thanks danadak and ahsrabrifat,
I have a circuit which will terminate any charging at a max voltage (60V). My battery is 17 series cells lifepo4 (51-62.5V).
The problem with a buck converter is the current limiting is absolute, ignoring voltage. I need a constant power (2200W) out of the generator, Amps x Voltage = Watt. Since the generator voltage (120V) is stable I need to keep an "eye" on the current, as the DC load voltage changes, from 51 - 60V and consequently also the current and total power.
So if I start with a discharged battery, set the AC current to 22A, as the DC voltage of the battery goes up, so the DC current goes down and I am using less of the available generator capacity. In reality I need to adjust the DC charging voltage, which my variac does. I have a electronic 10KW dimmer, (electronic variac) where a potentiometer changes voltage and so also current. I could use my motor drive in a bind, have not yet tried it.
A electronic potentiometer replacement circuit watching the AC generator current is what I need.
I have not yet found an "off the shelf" solution, there are 120V ac 3000W dc power-supplies available with settings for charge voltage and current limiting, but that will not keep my generator output stable. On those I would have to replace the current limiting pot (or voltage pot?) with a circuit watching the generator.