Inverter-fed induction motor drive systems with an instantaneous slip-frequency estimation circuit

This paper proposes a new inverter-fed induction motor drive system with a slip-frequency estimation circuit, in which the slip-frequency can be accurately estimated even under transient state without any speed sensor. The authors clarify the definition of "the instantaneous slip-frequency under transient state", and show some experimental results attained by the instantaneous slip-frequency estimation circuit.