Self controlled induction motor drive with variable DC link voltage

A system is proposed in which the voltage of the induction machine is controlled by variation of the DC-link voltage. Using variable DC-link voltage reduces the switching frequency of the inverter and the amplitude of the switched voltage. This reduces the inverter switching losses and the machine losses. Pulse width modulation (PWM) of the inverter is used only to lower the harmonics in motor torque and motor current. This results in a well-defined switching frequency of the inverter is used only to lower the harmonics in motor torque and motor current. This results in a well-defined switching frequency of the inverter and a simple strategy for the harmonic elimination. The PWM is switching only the reduced DC-link voltage, which is proportional to the machine voltage. Simulations show that the self-controlled induction machine with variable DC-link voltage behaves like a voltage controlled DC-machine. The implementation of a drive is described, and experimental results are presented to verify the feasibility of the proposed strategy