This doctoral thesis is dedicated to investigation of impedance source DC/DC converter with HF isolation implementation in interface converter for permanent magnet synchronous generator based variable speed wind turbine. The three new topologies of interface converter are proposed for PMSG based VSWT applications. The operation modes of the converters are investigated by means of computer simulations and results have been experimentally verified. The analytical evaluation of losses in active components of power circuit is made to compare feasibility of three circuits for small and micro wind turbine applications. The Laboratory prototype of qZS based DC/DC converter with HF isolation and controlled rectifier has been built and tested. The first chapter of the thesis is devoted to general overview of wind energy conversion technologies. Wind theory is given and wind velocity distribution is analysed to state the requirements for interfacing converter. Already known wind turbine systems are analysed to select the most suitable one for improvement and investigation. The converter topology with HF isolation transformer was selected for small and micro VSWT applications due to grate flexibility and offered galvanic isolation. The need for improved converter for VSWT applications is stated and main requirements is defined based on PMSG based VSWT characteristics. The second chapter is devoted to qZS based interface converter investigation and development. The new topologies based on qZS DC/DC converters with HF isolation are offered. These topologies are investigated by means of computer simulation in PSIM software and are verified experimentally. The third chapter is devoted to new topology of qZS based DC/DC converter with improved voltage boost properties. The potential applications are stated and analysed. Thesis is written in English, contains: 108 pages, introduction, three chapters, conclusions, 88 figures, 74 formulas, 12 tables, 100 references and 2 appendixes.