Gordon vd Heever

Gents, wonder if someone can help me. We are on a farm with no grid. We do have a generator though, but the cost of diesel is makes it unpractical to run the whole day. I am looking for an inverter with atleast be able to add two strings to it so that we cam imcrease the PV array over time. The size we are looking at here is about a 7.5kw PV Array. The catch here is that we only want to run power during the day with sunlight. For now, we do not want to add a battery. We want to install this in future, but for now only Solar Panels with an inverter which has a generator connection to it. What is the better option for an inverter that can work without batteries at this stage that can be upgraded within time. Thanks in advance with your help