Novel Single-Stage Current Source Inverter: Extension to Low-Speed Region in Motor Drive Applications

In motor drive applications, single-stage current source inverters (CSIs) can manage only a limited
speed range when the output voltage is greater than input
voltage, due to the intrinsic boost capability. The classical
solution adopted in low-speed region to control the input
dc current, consists in the insertion of a prestage power
converter. This article proposes a single-stage CSI that replaces the input inductance Ldc with coupled inductor. In
this way, it is possible to add the needed time interval for
the discharge of the magnetic energy of primary inductance
Lm when the converter works in low-speed region or at
standstill, extending the operating region of the converter.
This solution allows to increase the efficiency of traditional
CSIs for applications when the motor works most of the
time in the high-speed region, thanks to the single-stage
power conversion. Experimental and simulation results
driving a permanent magnet synchronous machine are
shown, confirming the validity of the proposed architecture.