# Best topology for an AC/AC switched-mode power supply

I need a power supply with two 100W isolated AC outputs. The output voltage must be a 24V 10kHz sine wave. The load regulation is not so important, what is truly important is the preservation of the sinusoidal wave shape under both rated load and no load conditions. Which SMPS topology is best suited for this purpose?

The first thing that came to my mind is an AC/DC SMPS (PFC + isolated step-down) followed by a PWM inverter. But I think that it is over-complicated for such a seemingly simple task.

The second thought was to get rid of the inverter. Indeed, we already have a rectangular AC voltage after the step-down stage. Maybe we can filter it instead of rectifying? I also found information about resonant converters, and that they can be used as AC/AC converters.

So what do you think about it?

• The input is 230V 50Hz mains.
• Load regulation: 20% is OK.
• The same with THD: 10-20% is OK.
• I'm sorry. I forgot probably the most important thing - efficiency! It should be at the level of an average SMPS, 80% or more.
• How do you get a "rectangular" ac voltage on the input side? How much distortion/harmonics can you tolerate in the output "sinusoidal wave shape"? You didn't tell us the frequency of the input but I assume that it is normal mains at 50/60 Hz...no linear filter will change that to 10 kHz. Commented Aug 11, 2018 at 20:08
• You want a 100W long-wave oscillator. Nothing else. Create that sine the analogue way, it's much simpler than any kind of D/A mumbo-jumbo. Commented Aug 11, 2018 at 20:31
• @ElliotAlderson Yes, the input is 50Hz 230V mains. As for the rectangular voltage I meant the output of the step-down stage. The PFC stage rectifiers mains voltage and converts it to the 400V DC. The step-down stage chops the DC at high frequency and feeds the isolation transformer. At the output we have a low-voltage high-frequency rectangular wave. By filtering it you can get a required sinusoidal voltage. At least I hope so. Commented Aug 11, 2018 at 20:33
• I go so far even recommend a motor-generator. Commented Aug 11, 2018 at 20:34
• If load is 100W what is allowed voltage drop or load regulation error 2% 10%? 1%? Maybe you just need to buy a stereo audio power amp. You specs are too thin. Commented Aug 11, 2018 at 20:43