TDK's bidirectional converter serves energy storage and recycling apps



TDK announced the introduction of TDK-Lambda’s EZA2500-32048 bi-directional converter, suitable for energy storage systems with rechargeable batteries. This 2500W digitally controlled, compact 1U power supply can automatically change conversion direction from high voltage dc sources, powered by solar or wind, to 48Vdc batteries and vice versa.

In addition to small to medium sized energy storage, applications also include lithium-ion battery testing as well as the utilization of regenerated energy from robots, cranes, autonomous ground vehicles and lifts. For example, the EZA2500 can replace the large power resistors currently used for lift braking and instead use that previously dissipated energy to charge batteries. That storage can then be used to either provide peak power for high torque demands or as battery back-up for power cuts.

Product highlights

• Designed for energy regeneration applications

• True bi-directional converter with single transformer

• Low profile: 2500W in 1U x 19’ rack

• Full digital conversion & control, RS485 interface

Key specifications

• Grid voltage 320Vdc nominal, (300-380Vdc)

• Battery voltage 48Vdc nominal, (36-60Vdc)

• High efficiency up to 94.6%

• Multiple operation modes to suit many applications

Typical applications

• Electric motor energy re-generation/storage (lifts, cranes, etc)

• Battery test systems energy re-generation to avoid energy waste

• Smart-grid, particularly “micro-grid” applications

The EZA2500 operates from, or supplies, either a 36 to 60V or 300 to 380V dc voltage with maximum currents of +/-52A or +/-7.8A respectively. The output voltage and current can be programmed and monitored using the RS-485 communications port. For larger systems, multiple units can be operated in parallel by setting the unit to “droop mode” current share via the RS-485 interface. A variety of alarm signals are also accessible, as well as remote on/off and under/over voltage functions. The EZA2500 will operate at full load in an ambient temperature of -10 to +40oC.

Internally, the twin DC-DC converter design enables continuous transitional switching between charge and discharge states to maintain the stability of the bus voltage. Operating efficiencies of up to 94% are achieved with the use of full digital control. The converters are isolated – 3kVac from the high voltage (grid) to low voltage (battery) input/outputs, 2kVac from grid to ground and 500Vac from battery to ground.

The dimensions for the EZA2500 are 43.6mm (1U) high, 423mm wide and 400mm deep. Certifications include UL/CSA 60950-1, EN 60950-1 and the CE mark for the LVD and RoHS2. The EZA2500 is backed by a five-year warranty.