Patent ID: 7791298

Claim:
A motor driver system comprising: an inverter configured to apply a three-phase voltage to a motor; an inverter driver configured to generate a reference voltage to the inverter to control a motor speed to follow a reference speed; and a motor protector configured to control the inverter driver so that a value of the reference voltage is equal to or lower than a predetermined voltage value, wherein the inverter driver includes: a speed controller configured to generate a reference current value to control the motor speed to follow the reference speed; a reference current generator configured to generate a d-axis reference current and a q-axis reference current using the reference current value and a reference current angle value; and a reference voltage generator configured to generate the reference voltage to control a d-axis current and a q-axis current of the motor to follow the d-axis reference current and q-axis reference current, and wherein the motor protector changes a reference current angle value of the reference current generator when the reference voltage value is larger than the predetermined voltage value.