Is the frequency to be varied continuously? I mean, could you divide the range into subranges, and move from one to another with some discontinuity, for example moving from one transformer ratio to another?
In the hypothesis of changing the ratio at some steps, I think it would be feasible, otherwise I think it would be quite difficult to control a current by means of an actuator voltage that goes across 3 orders of magnitude...
I wish the frequency of the sinusoidal current to be varied continuously, or in step of 10Hz.
I'm not sure if the following works:
Audio Power Amplifier (e.g. LM3886) ==> Step-Up Transformer ==> LoadWith +/-35V supplies, the LM3886 is capable of supplying 50W at 8ohm (i.e. Iout=2.5Arms and Vout=20Vrms).
The transformer is designed to have a step-up turn-ratio of 5. Thus, the output voltage of the secondary winding will be 20Vrms*5=100Vrms, which is higher than the required 89.05Vrms. For a secondary output current (i.e. load current) of 0.3536Arms (i.e. 1.0Apkpk), the primary current will be 0.3536*5=1.768Arms, which is still within the output current capability of the LM3886.
For frequencies lower than 10kHz, the output Vrms of the LM3886 is decreased to maintain the load current of 1.0Apkpk.
The impedance of the transformer should be made as small as possible. The transformer should not be saturated when the secondary current is 1.0Apk-pk (10kHz). What do you think about using toroidal core to build the transformer?
Do you think the above idea will work?
Please kindly advise if you know a better power amplifier with high supply voltages and high output current.
Thanks.