PWM HYBRID INVERTER DRIVE CIRCUIT TOPOLOGIES THAT EMPLOY A DUAL VOLTAGE AND CURRENT DC-LINK

This paper describes a three-phase ''hybrid'' inverter drive circuit topology, suitable for high-power applications, that supplies the output inverter with a dual dc-link consisting of a constant current and a constant voltage. Four basic hybrid drive types are described: freewheel diode, buck, boost, and the PWM rectifier. The resultant drive topologies combine the current overload protection features associated with a current source inverter together with the high performance associated with a pulse-width modulated voltage source inverter. Three-phase pulse-width modulated schemes are investigated to show that the output inverter bridge can be used to control the dc-link voltage and the dc-link current without interfering with the pulse-width modulated voltage waveforms fed to the motor. Computer simulations and experimental results are used to demonstrate the operating features of the various drive types.