Digital Control Generations -- Digital Controls for Power Electronics through the Third Generation

Abstract

Digital control in power electronics can be divided into three generations. First-generation digital controls use digital outside the loop in communications, setup, and supervisory roles. Second generation digital controls use digital processes inside the loop, including discrete-time feedback loops and sometimes even digital signal processing. Today, first-generation digital methods are expanding quickly, as new communication protocols and adjustable analog loops become common. Even companies that continue to design analog controls for power electronics often include these types of digital processes. Second-generation digital controls are a hot topic right now, as real-time digital controllers become feasible. In third-generation digital controls, the digital process functions directly with individual switches to push performance up to the physical limits of power electronics. A digital switch decides when it must turn on or off. The control is on direct switch timing rather than a converter duty ratio or a setting. Extreme performance is possible with this approach, such as converters that do not exhibit output disturbances when confronted with load or line step changes. The talk compares these different arenas, all of which are current active topics in power electronics, and shows what can become possible as the third generation develops.