Brassia won't bloom

[monivik]

I've had this Brassia (originally it was one) for many years. In fact it was so huge it was growing out of it's pot so I divided it into three. In fact, it's been two years since I divded it but even longer ago since it last bloomed. It seems to be doing all right, it's making new pseudobulbs, but no flowers. It's kind of a bummer, because without flowers it's kinda boring
I mean I really enjoy flowers, even should it be once a year like with Oncidiums. But this hasn't done anything but make pseudobulbs in years.

What am I doing wrong and how could I encourage it to flower? I live in Northern Europe and we have seasons here, summers are nice and warm and bright. I do keep the plants indoors but wintertime the temperature in the house is 19 C (66.2F) - 20C (68F) mostly during the day. We only put on the heater in the evenings when we are home from work.

I do have growlights, so in terms of the low light of the winter this should help. They're not the closest to the grow lights but it should still make a difference I should think.