Can anyone help with PWM voltage regulator for 120 V solar battery charging

I am setting up a solar power system to charge a 120 volt 100Ahr battery, which powers a UPS (inverter). Unfortunately, I cannot find a charge regulator for such a high voltage battery. So I need to build one. I will probably use a PWM controller IC, but there are so many types available, I'm not sure where to start. There are current mode PWM controllers, DC DC converters, power supply controllers etc.

I have four solar panels with a Vmp of 35, so at full power, they produce 140v, at 9 amps. The battery voltage should be regulated to 137 volts. As the battery reaches full voltage, I want the current to taper off, and the excess power from the solar array, to be diverted to another use. So my charge regulator will have two outputs, one that is regulated for battery charging, and the other that starts to output only once the battery is charged. There are PWM ICs with A and B outputs. I think they are in "opposite phase" to each other, so when one is high, the other is low, and therefore, I could use these outputs to achieve my aim Is that right? I am assuming N-channel FETs are what is required in my application? I am thinking of BUZ30A FETs which are reasonably priced, 200v, 21A rated.

Any comments would be helpful. Thanks.

Regards, Mike