The 20 year old Sharp microwave/convection in our 1983 Newell finally quit on us. I want to but a new microwave/convection oven to replace it. For short periods of time (may up tp 30 minutes) the new microwave will be powered by our Heart Freedom 3000-watt inverter. I have read that some microwaves work better than others using this modified sine wave power source. Any suggestions as to brand or model?