adjusting frequency in LLC designs

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My understanding of LLC designs is that they use frequency to control output voltage in a fixed secondary turns transformer witha fixed resonant frequency.

Here is my problem:

- I need the supply to operate with a changing resonant frequency (fixed for each unit).

- I can't alter the turns ratio on the transformer and I need to set the switching frequency.

How can I use the Hiper PLC to do this ?

Can I change from an LLC mode to a different one ?

The PLC appears to be a continuous mode mechanism. Maybe I need discontinuous but the LCS model does not seem to work for high voltages(using the PI-expert s/w). Probably I am not setting something correctly...


Characteristics are:

- the lamp connected to the output has a capcitance, which cannot be determined beforehand, and is different for every device.

- The resonant frequency cannot be determined at manufacture only when deploying.

- The resonant frequency and output voltage both need to be independently adjustable to achieve the desired effect when deploying.

 - output wattage is in area of 80-150W

 - output voltage is in range 7000 to 20000 V

 - AC output. not required to be tightly regulated.

 - frequency range of output needs to be between 20kHz-100kHz  (PLC suggests 30k minimum)

 - magnetics can be large to enable sufficient power to be used. Typically something like

  TSC Ferrite International 81-33-16 core in 7070 material

end result looks like:


other examples:


Can you offer any advice please.

PLC frequency is controlled by VCO pin voltage. If you can modify your controller loop to control you VCO voltage, you can control your frequency. We don't have a promoted solution for that.

PLC can operate at 20kHz although suggested minimun frequency is 30kHz.