A high performance voltage-regulated CSI AC induction motor drive

AC adjustable speed drives employ mostly a voltage source inverter (VSI) to control the motor armature, despite the inherent advantages of the current source inverter (CSI) topology. This is partly due to the current source nature of the topology and the complexity of the controls required, the voltage source being a more universal power supply and being easier to control. This paper demonstrates that a voltage-regulated CSI offers the same features as its VSI counterpart, together with the added advantages inherent in the CSI topology, namely suppression of high dv/dt across motor windings, built-in short-circuit protection, natural power reversibility and high reliability. A constant V/f scalar speed controller is implemented in this paper to illustrate the high steady state and dynamic performances offered by the topology. Its flexibility also allows for increased system efficiency and output voltage quality. Simulation results are given for a 5 kW induction motor drive