Abstract
A vector control scheme without motor speed and voltage sensors allows high performance speed control of a squirrel-cage induction motor fed by a voltage source PWM inverter, using only a motor primary current sensor.
A new scheme for simplifying the system configuration by removing the speed and current regulators is proposed. The effects of setting errors in control parameters on speed control accuracy and torque characteristic are analyzed, and it is clarified that the control performance largely depends on stator resistance deviation in the low speed range.
In order to adapt the control parameter dealing with the stator resistance to the actual value, a parameter adaption method is developed by consideration of a magnetizing current deviation characteristic for the setting error. A design method for the parameter adaption system is also clarified, and its control characteristic and effectiveness are verified by digital simulations and experiments.
The proposed system is controllable without torque reduction and good speed accuracy, within ±1% from low speed (about 1 Hz), is obtained. This system fits a wide range application and can serve as an alternative to V/f control due to its simple control configuration and good control performance.
