Novel　AC/AC　converters　with　high　frequency　ac　link　are　composed　of　two　kinds　of　AC/AC　converters,　which　are　voltage　mode　based　on　Forward　converter　and　current　mode　based　on　Flyback　converter.　The　circuit　configuration　and　topology,　control　strategy,　principle　characteristics,　design　criteria　of　the　key　circuit　parameters,　and　principle　prototype　of　two-kinds　converters　are　deeply　and　comparatively　investigated　firstly　in　this　paper,　and　important　conclusions　are　obtained.　Compared　with　the　voltage　mode　converters,　the　current　mode　converters　have　the　characteristics　such　as　more　concise　circuit　topologies,　wider　range　of　the　input　voltage,　higher　quality　of　the　output　waveforms,　higher　reliability,　lower　cost,　lower　conversion　efficiency　and　more　applicability　to　the　small　power　conversion　fields.　Research　on　the　comparisons　of　two　kinds　of　converters　supplies　the　key　technical　foundation　on　new　type　electronic　transformers,　regulated　sinusoidal　ac　power　supplies,　and　ac　regulators.