Control Scheme for Switched Reluctance Drives With Minimized DC-Link Capacitance

This paper presents a control scheme that allows minimization of dc-link capacitance in switched reluctance drives (SRDs). In switched reluctance motors (SRMs), the demagnetization energy of the outgoing phase causes a voltage increase in the dc-link. Therefore, large dc-link capacitors are required in conventional drives to absorb this energy to avoid overvoltages. The proposed control scheme balances the power flow between phases in such a way that the demagnetization energy of the outgoing phase does not flow back into the dc-link but directly into the incoming phase. Using this scheme, electrolytic capacitors can be replaced by film or ceramic capacitors leading to higher power density, longer lifetime, and higher reliability.