High-power, high-voltage 40kW, 450V DC/DC converter, Zekatex

The YellowBee DC/DC converter is a bidirectional cabinet mountable DC/DC power converter with many different applications. It can be set up for charging/discharging of either a battery bank or a supercap string. Moreover, the converter can be stacked for achieving higher power with no communication between them. The rated current overload capacity allows the YellowBee DC/DC to be used in highly dynamic applications.

Having numerous communication interfaces including Ethernet, RS485 and CANBus and utilizing Modbus, makes the integration with your industrial network an easy task. Profibus interface is also available using the Zekatex GreenBee Modbus-to-PROFIBUS Gateway. The integrated Modbus master allows different Modbus slaves to be attached to extend IO and functionality.

Several digital and analog inputs and outputs are available for additional programming and logic allowing extra flexibility during the system design or an ongoing project.

Powered by the ZekaStream™ technology you will be able to display the electrical characteristics and diagnose the health of the system with an unprecedented resolution for the industry. Only one such device in your design is enough to change the way you commission the whole power plant.

Providing various modes of operation, programmable limitations and additional logic integration possibilities, it can easily turn into the heart of your energy storage, load balancing, hybrid/electrical or microgrid system.

Having a design with fully integrated control, power units and filter bank balances the size and the weight of the installed components. Mounting and servicing of these usually heavy components within the cabinet becomes a much more comprehensive task.

The YellowBee DC/DC converter has already proved to be a versatile, multi-application devices and can easily fit in applications such as energy storage systems, battery chargers, load balancers, microgids or any kind of hybrid/electrical systems.


Technical specification



Nominal power

40kW (battery voltage > 200 Vdc)

Maximum DC-link voltage

450 Vdc

Minimum DC-link voltage

Battery voltage + 50 Vdc

Maximum DC-link current

115 Adc

Maximum battery voltage

410 Vdc

Minimum battery voltage

200 Vdc

Nominal battery current

200 Adc

Maximum battery current

220 Adc (not more than 20 min)


~ 98% (load power > 20%)

Energy transfer direction


DC-link capacitance

240 uF / 700 Vdc

Switching frequency

25 kHz


Forced air – internal fans

Cooling air flowrate

150 l/min or 9 m3/h

Power supply voltage

24 Vdc ±10%

Power supply current with fans on

< 2 A

Power supply current with fans off

< 1 A

Degree of protection


Mechanical dimensions (W x L x H)

350 x 400 x 186 mm


28.5 kg

Operating temperature

-20 °C - 55 °C (derating over 40 °C)


96 %, not condensing

3x Analog Inputs

145 Vdc

5x Analog Outputs

0-20 mA

6x Digital Inputs

+24V - +110V (> 15V on)

12x Digital outputs

External Power Supply: Up to 125 V, 200mA

4x relay outputs

250 Vac / 5A, 30 Vdc / 3 A


Communication interfaces



1x Modbus RTU slave


1x Modbus RTU master


1x Modbus TCP slave


1x CAN

CAN (custom protocol)





IEC 61000-4-4:2004

Electrical fast transient (Burst) ( 2 kV power , 1 kV signal )

IEC 61000-4-5:2006

Surge voltage ( 0.5 kV L-L , 1 kV L-GND )

BDS EN 61000-4-6:2009

Conducted radio frequency interference ( 3 Vrms / 150 kHz – 80 MHz )

IEC 61000-4-2:2009

Electrostatic discharge ( 6 kV contact , 6 kV air )

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