A dead-beat adaptive hysteresis current control

Abstract

This paper proposes a new digital algorithm for the implementation of the fixed-frequency adaptive hysteresis current control for voltage-source inverters. The key features of the new algorithm are the minimization of the analog external circuitry, the capability to automatically compensate for the inverter deadtime effects without appreciable delay and a tight synchronization of the inverter voltage pulses with an external clock. The synchronization is actually inherent in the implemented algorithm and does not require additional control loops; the stability problems affecting all the solutions proposed so far are, therefore, avoided and a steady switching frequency is achieved. Even though the complexity of the algorithm is compatible with many conventional microcontrollers' performance level, the implementation with a commercial digital signal processor is considered in order to achieve ultrasonic operating frequency and to test the effectiveness of the solution in more demanding conditions.