- Chopper A DC-DC converter that steps up or steps down DC voltage. - Four-quadrant chopper Can operate with positive and negative voltage and current, allowing for bidirectional power flow. This enables it to act as a DC-DC converter, a DC-AC inverter, and in certain configurations, emulate some functionalities of rectifiers and AC controllers. - Cycloconverter An AC-AC converter that produces a variable frequency, variable voltage AC output from a fixed frequency, fixed voltage AC input.