200 W Kit - FAQ

How do I purchase the 200W kit?

Please do contact your local Würth Elektronik expert, or do get in touch via www.we-online.com/wirelesspower/200Wkit and we will contact you to arrange procurement.

What is the working input voltage and current of the transmitter?

 The working input voltage is 19 – 24 V and the working input current shall not exceed 10 A.

What is the operating frequency? Can it be altered?

By default the kit is set to automatic mode, where the frequency is adjusted to 110 kHz - 150 kHz, depending on the coil distance. In the manual mode the frequency range is between 100 kHz and 205 kHz. The operating frequency can be altered in the firmware and by choosing the desired resonant tank at the same time.

Why does the kit contain a power supply capable of 150 W instead of 200 W?

For temperature and safety reasons the power supply as delivered provides only 150 W. For usage up to 200 W then air-cooling is needed.

What is the minimum load required for the receiver?

The load should be set to at least 0,1 A - 1 A.

What kind of coils are used for RX and TX?

For both coils the WE-WPCC coil 760308102142 is used.

Which other coils can be used?

Every coil which can handle the desired power rating.

Does the design support any foreign object detection (FOD)?

No, at the moment there is no industry standard FOD solution for this power level and so no FOD is implemented in this kit. We do recommend that the user develops an FOD implementation appropriate for their application. It can be added in the firmware.

What is the system efficiency?

The efficiency is 90 % at a distance of max. 10 mm.

What’s the maximum coil distance?

The maximum coil distance is 10 mm.

Is the voltage or the coil current used for transferring the data?

The current in the RX coil is modulated to transfer the data.

Is the communication closed loop?

The communication is unidirectional from RX side to TX side.

There is a RS232 interface. How is it used? Is it removable?

With this interface the input parameters and the transferred data can be shown. This interface is removable.

Is the communication protocol of the kit compliant to the WPC standard?

No, the used communication protocol is a proprietary solution.

What are the data rates for the communication?

The data rate is about several bytes per second and depends on the coil distance.

What is the expected rectifier voltage on the receiver?

On the receiver the clamped voltage is set to approximately 19 V.

What’s the temperature of the RX coil, TX coil and MOSFETs under operation?

The temperature depends on various system parameters: operating frequency, coil distance and the cooling.

What are the possible hazards?

i. A possible hazard is e.g. the operation without any load which can cause a high voltage at the output. This could lead to a destruction of the receiver board.

ii. Furthermore high temperatures on some components on the TX side can occur.

iii. For an output power above 150 W additional air-cooling is needed.

iv. Please make sure that the output voltage does not exceed 40 V at the receiver output when turning the incremental encoder in manual mode. A higher output voltage could lead to a destruction of the receiver board.

Can I use the kit at higher power levels, greater than 200 W?

Yes, the kit is intended to be scalable. By selection of components with higher power specification and with appropriate safety and cooling methods then 1 kW and higher is possible. The components below should be reviewed and upgraded if appropriate for your target implementation and power level.

On transmitter side:

  • EMI-filter: consider common mode choke with a higher current rating
  • Polarity protection & Full Bridge rectifier: transistors with higher current and voltage capability will be required. Additional cooling (bigger copper area, heat sink) may be required.
  • Resonant Tank: capacitors must have sufficient current and voltage ratings. Film capacitors shall be used instead of ceramic capacitors.
  • Current sensor: the current rating of the shunt resistor has to be reviewed.
  • Intermediate circuit capacitors (electrolytic capacitors): the capacitors have to be increased, e.g. for a power level of 500 W the capacitors have to be increased by a factor of 2-3.
  • Step Down Regulator Module: depending on the used input voltage, consider the appropriate step down regulator module.
  • DC-connector: review capability for the desired power level, e.g. the input voltage can be split to several pins.
  • Terminal block: review capability for the desired power level.
  • Transmitter coil: a coil with a higher current rating has to be used
  • Firmware: increase the maximum current and voltage parameter values in the code

On receiver side:

  • Synchronous rectifier: review the current and voltage ratings and consider appropriate transistors and increased cooling (bigger copper area or heat sink)
  • Similarly as for transmitter side, on the receiver side the Current sensor, Electrolytic capacitors, Terminal blocks, Receiver coil and Firmware must be reviewed and updated as appropriate

Where can I address my questions?

Please address your questions to the local Field Application Engineer of WE or to wirelesspower@we-online.com with the email subject ‘200W Kit’