The cabinet is the wrong shape to photograph well. Two metres tall, a metre and a half wide, IP54 enclosure, painted RAL 7035. What it does inside that enclosure is more interesting: it steps a 750 V DC battery bus up or down to a 1000 V DC link that the site shares with the rooftop PV and the grid-tie inverter.
The site is a container-handling yard on the west side of Singapore. Diesel generators used to back the yard lighting and the gate-house during the day, then spun down overnight when the price of grid power dropped. The site owner wanted to put a battery in: charge it from the rooftop solar when the sun was up, discharge it when the diesel would otherwise be running, and stay grid-connected the rest of the time.
What we shipped
- One 2 MW bidirectional DC/DC cabinet, 750 V DC battery side, 1000 V DC link side
- One SOC balancer module, 80 kW, working with the cabinet on DC bus equalisation
- Local controller with Modbus TCP and IEC 61850 for the SCADA tie-in
- 72-hour burn-in report, signed on the dispatch day
Two things worth noting
First, the battery side and the link side share a common DC bus only through the cabinet. There is no direct battery-to-PV wiring, which means the cabinet can be bypassed for service without taking the whole site down. The integrator asked for that, and we ran the cable layout with them on a video call before the steel was cut.
Second, the cabinet was specified for tropical climate, so we fitted a thicker heatsink profile than the temperate default and used a conformal coating on the control board. Singapore humidity will kill an uncoated board inside a year.
Lead time and dispatch
Order to ship: 45 working days. The integrator handled marine shipping and on-site install; we joined the commissioning by video for one day, then a service engineer flew out for the final acceptance test a week later. The site went into commercial operation the following month.
For enquiries about 2 MW-class bidirectional DC/DC cabinets and SOC balancers for distributed storage or microgrid projects, contact: 58298175@qq.com / +86-181-5931-0123.
