A frequency converter is an electrical device that changes the frequency of an input power source to a different output frequency. This is essential in applications where equipment requires a specific frequency to operate efficiently, such as in industrial machinery or renewable energy systems. These converters can be used to adapt power from AC (alternating current) to DC (direct current) or to modify the frequency of AC power itself. By doing so, they help ensure that devices run smoothly and can improve energy efficiency in various applications, including electric vehicles and wind turbines.