Low-complexity constrained control of the opposed current converter using quadratic control contractive sets

Abstract

The opposed current converter (OCC) is a high-precision power amplifier that does not require blanking time in between switching and hence has high output quality. Like most of industrial power amplifiers, OCCs are typically controlled by classical control methods, which are simple and able to guarantee certain local optimality. However, physical constraints of the system are often neglected in the classical control design, which might lead to unreliable operation. More advanced control methods that can handle constraints are often of high complexity. This paper proposes an explicit control design method for the OCC based on a sequence of quadratic control contractive sets. The proposed controller can be computed by a single linear matrix inequality. It is proven to guarantee stability, locally optimal performance, constraints satisfaction and it has low complexity. Experimental results on a prototype OCC demonstrate the effectiveness of the proposed method.