High-power, high-voltage 200kW, 750V 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 and power units balances the size and the weight of the installed components. The device requires an external filter bank like the intelligent, MCU controlled, air-cooled I-Fighter Inductors Block. Having such kind of separation, 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. It has already been successfully installed on several tugboats including the first EU hybrid tugboat.


Technical specification



Nominal power

200kW (battery voltage > 800 Vdc)

Minimum battery voltage

100 Vdc

Maximum battery voltage

1000 Vdc

Nominal battery current

250 Adc

Maximum battery current

300 Adc (not more than 20 min)

Minimum DC-link voltage

Battery voltage + 50 Vdc

Maximum DC-link voltage

1200 Vdc

Maximum DC-link current

200 Adc


~ 98% (without external inductors)

Losses at nom. current and DC-Link voltage

< 3 kW

Inductors losses at nominal current

< 1 kW

Energy transfer direction


DC-link capacitance

1100 uF / 1200 Vdc

Switching frequency

4 kHz


Forced air – internal fans

Cooling air flowrate

250 l/min or 15 m3/h

Power supply voltage

24 Vdc ±10%

Power supply current with fans on

< 6 A

Power supply current with fans off

< 1 A

Degree of protection


Mechanical dimensions (W x L x H)

366 x 465 x 240 mm


30 kg

Operating temperature

-20 °C - 55 °C (derating over 45 °C)


96 %, not condensing

1x Analog Inputs

1200 Vdc

2x Analog Inputs

±20 mA

5x Analog Outputs

0-20 mA

3x 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






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 )


Mechanical vibration of shipboard equipment

BDS EN 60068-2-1:2007

Environmental testing – Test A: Cold ( 5 °C)

BDS EN 60068-2-2:2008

Environmental testing – Test B: Dry heat ( 55 °C)

BDS EN 60068-2-78:2013

Environmental testing – Test Cab: Damp heat ( 40 °C)

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