Developing power electronics for manufacturing: System-level design offers an effective approach
Emerging markets such as renewable energy, plug-in electric vehicles and smart grids are driving new demand for power electronics of ever-shrinking size, weight and cost that can boost performance in operating environments of challenging harshness. Meanwhile, designers charged with enabling these new technology breakthroughs are increasingly aware that their cutting-edge component, module and system designs must ultimately be assembled and manufactured in high volumes.
One of the most effective approaches to design for manufacturing is to take a system-level or modular approach. This allows designers to adapt elements from different systems to create new yet similar applications that can move seamlessly to the manufacturing line. In addition to saving time on front-end design, an integrated modular approach to system design can help reduce overall cost, and speed time-to-market.
The emerging application landscape
Continued growth in renewable energy sources is fueling demand for advanced grid-tied inverters. Unlike conventional inverters that regulate and convert direct current (DC) into alternating current (AC), grid-tied inverters will require more application-specific features, such as phase locked loop control, anti-islanding and maximum power point tracking digital control algorithms as essential components for standard operation.
The emerging smart grid is also sparking new applications, such as sub-megawatt-scale micro-grid systems. Drawing both from the national power grid and renewable energy sources, micro-grids distribute electricity to a local community or an industrial campus.
The concept further extends to household-scale nano-grids or "smart houses." Both of these emerging structures will need to rely on a mixture of traditional AC and DC distribution through sophisticated power optimization controls, and handle both AC and DC loads, such as appliances, car batteries, consumer electronics or televisions through universal AC and DC grid plug-ins.
At the component level, these emerging grid structures will require development of powerful, yet compact central units able to produce bi-directional AC/DC and DC/DC power conversions from different sources, and return excess power to the larger grid, or energy storage devices. The end goal is to achieve "net zero" energy objectives after satisfying the power needs of the system's various loads.
New uninterruptible power supplies (UPSs) – once only for the grid and industrial systems – are also emerging to enable in-home power distribution platforms. In addition to promoting greater energy efficiency and less heat, these UPS systems could also usher in a new generation of appliances with smaller form factors, since today's televisions, washing machines and other heavy duty appliances owe their bulk and weight to power supply components with isolating step-down transformers as their integral parts.
Driven by the steady rise in oil prices, the transportation industry is also calling for new developments in power electronics. Automotive and other transportation sectors require new architectures for emerging generations of plug-in electric (PHEV) and hybrid electric vehicles (HEV), including internal battery charging DC/DC converters and propulsion/starter DC/AC motor drives. Both are bi-directional configurations that must accommodate power transfer between the battery, motor drive and external DC power grid. In addition to handling higher power densities, these new power electronics systems will also need to maintain performance in harsh and demanding environments.
Finally, industrial applications from semiconductor production to conventional assembly lines will drive new developments in power electronics. The sector is increasingly hungry for grid-tied AC/DC power rectifiers with power factor correction (PFC) that can drive production systems more efficiently and comply with electromagnetic interference regulations and other international technical standards. Such systems typically demand additional DC/DC converters, UPS systems and DC/AC inverters or motor drives.
Elsewhere, new advances in magnetic materials, including solid-state "smart" transformers, are fueling new research in non-traditional power converter topologies, motors and motor drives. Current breakthroughs in materials for switch- and synchronous-reluctance motors could enable these systems to become competitive with currently predominant permanent magnet (PM) systems used in high power density, high-efficiency motor drives found everywhere, from industrial applications to home appliances.