The Through-Pass Inverter and Its Application to the Speed Control of Wound Rotor Induction Machines

A new inverter type suitable for variable voltage ratio dc-ac power conversion is introduced. It was developed particularly for the control of speed and torque of wound rotor induction machines. The inverter "short-circuit" and "inversion" modes are described and examples of some means for switching from one mode to the other and for their time ratio control are shown. The behavior of the induction machine-rectifier-through-pass inverter cascade is analyzed and a simplified block diagram is deduced. Experimental results confirming the theory are given. The problems associated with the application of thyristors to the scheme for the slip power recovery are pointed out.