DC-link voltage control for Switched Reluctance Drives with reduced DC-link capacitance

This paper presents a simple control method for Switched Reluctance Drives that enables the implementation of significantly smaller dc-link capacitors compared to conventional SR drive inverters. This is achieved by a direct control of the dc-link voltage. During the commutation of two neighboring phases, the switching states of the outgoing phase are chosen and alternated in such a way, that the dc-link voltage stays within a predefined range. The implementation is similar to a conventional current hysteresis control. In this paper, first an introduction to the problem is given followed by the description of the proposed control. The functionality of the control is shown by computer simulations and proven by measurements. Due to the fact that the control manipulates the current shape during demagnetization, also the influence on the overall drive efficiency has to be studied, which is done by computer simulations at the end of this paper.