The power ratings of today's energy systems are getting progressively higher as utilities, companies, and consumers seek higher efficiencies, lower costs per unit of power/energy, and new applications (e.g., commercial-scale electric airplanes). The average nameplate capacity per wind turbine, for example, as increased from less than 1 MW per turbine in 2000 to more than 3 MW per turbine today, with offshore turbines typically rated at more than 10 MW per turbine. Power conversion equipment has enjoyed minimal evolution during this time period, however, with newer, large-scale systems typically implementing power electronic systems featuring outdated paradigms that were designed decades ago for much smaller systems. There is a need for rectifer-generator systems that are designed to optimize the systems of today, including accommodating their larger size and their shift in importance from pilot demonstrations (in which reliability was nice to have but seldom critical) to critical components of our energy infrastructure. 

University innovators have developed an integrated rectifier-generator system that improves power electronics architecture, reducing the bulkiness, weight, failure modes, and cost (both up-front and maintenance) of megawatt-rated systems. The architecture simplifies hardware and control schemes, improves efficiency of switch voltage ratings, and achieves ac-dc conversion at lower cost than conventional means. More specifically, the design eliminates many active rectification components in favor of a multiport permanent-magnet synchronous generator (PMSG) with series-stacked power converters. Instead of routing all power through the active rectifier, only a fraction is processed by the active rectifier which reduces loss and system wear. The system reduces ripple to levels at or below that of conventional designs while improving efficiency and eliminating common failure mechanisms. 

More information

• https://ieeexplore.ieee.org/abstract/document/9117045
• https://ieeexplore.ieee.org/abstract/document/8862851