Abstract: A method for controlling a multiphase synchronous motor, for a motor flux vector includes setting a first winding of the motor to a floating state in which the first winding is electrically floating; setting a voltage across a second winding of the motor for a first period; receiving first voltage samples associated with the first winding in the first period; setting the voltage across the second winding to a second period, in which the first period and the second period are periods of one or more pulse width modulation cycles, in which a polarity of the voltage across the second winding in the second period is opposite to a polarity of the voltage across the second winding in the first period; receiving second voltage samples associated with the first winding in the second period; and determining a position of the rotor based on the first and second voltage samples.

Abstract: A method for controlling a multiphase synchronous motor, for a motor flux vector includes setting a first winding of the motor to a floating state in which the first winding is electrically floating; setting a voltage across a second winding of the motor for a first period; receiving first voltage samples associated with the first winding in the first period; setting the voltage across the second winding to a second period, in which the first period and the second period are periods of one or more pulse width modulation cycles, in which a polarity of the voltage across the second winding in the second period is opposite to a polarity of the voltage across the second winding in the first period; receiving second voltage samples associated with the first winding in the second period; and determining a position of the rotor based on the first and second voltage samples.

Abstract: A method and apparatus are provided for detecting a rotor lock condition in a sensorless permanent magnet synchronous motor. A BEMF observer determines an estimated rotor speed {circumflex over (?)} and a first BEMF voltage value in an estimated rotor-related ?,? reference frame. In addition, a second estimated BEMF voltage value is calculated in a rotor-related d,q reference frame based on at least a first motor constant and an estimated rotor speed {circumflex over (?)}. After generating a BEMF error filter value from the first and second estimated BEMF voltage values and calculating a BEMF error threshold value as a function of the estimated rotor speed {circumflex over (?)} that is subject to a minimum threshold BEMF value, a rotor lock condition is detected based on at least the BEMF error filter value and the BEMF error threshold value.

Abstract: A device for determining a rotor position in a polyphase electric motor having a first phase, a second phase and a third phase. A power control unit applies a first voltage on the first phase, and a second voltage on the second phase, the first voltage and the second voltage being periodic signals of opposite polarity, alternating between a first part and a second part of the alternating period, such as square waves. A sample unit samples a third voltage on the third phase for acquiring a first sample at a first instant in the first part and a second sample at a second instant in the second part, and a difference value between the first sample and the second sample. The difference value represents a mutual inductance between the stator coils due to the rotor position. A determination unit determines the rotor position based on the difference value.

Abstract: A method and apparatus are provided for detecting a rotor lock condition in a sensorless permanent magnet synchronous motor. A BEMF observer determines an estimated rotor speed {circumflex over (?)} and a first BEMF voltage value in an estimated rotor-related ?,? reference frame. In addition, a second estimated BEMF voltage value is calculated in a rotor-related d,q reference frame based on at least a first motor constant and an estimated rotor speed {circumflex over (?)}. After generating a BEMF error filter value from the first and second estimated BEMF voltage values and calculating a BEMF error threshold value as a function of the estimated rotor speed {circumflex over (?)} that is subject to a minimum threshold BEMF value, a rotor lock condition is detected based on at least the BEMF error filter value and the BEMF error threshold value.

Abstract: A method and apparatus for electric motor thermal management is provided. A thermal model allows estimation of temperatures of an electric motor and determination of a motor overload condition. The thermal model is based on electrical parameters that can be measured in a motor control circuit. An electric motor control method and circuit utilizes a back electromotive force (EMF) measurement circuit, a processor coupled to the back EMF measurement circuit for receiving a back EMF measurement and for calculating a thermal model of the electric motor, the thermal model based on a stator-to-ambient thermal resistance value accounting for a sum of a stator-to-case thermal resistance and a case-to-ambient thermal resistance, and an electric motor driver circuit coupled to the processor for providing drive signals for controlling delivery of power to the electric motor based on the thermal model of the electric motor.

Abstract: A device for determining a rotor position in a polyphase electric motor having a first phase, a second phase and a third phase. A power control unit applies a first voltage on the first phase, and a second voltage on the second phase, the first voltage and the second voltage being periodic signals of opposite polarity, alternating between a first part and a second part of the alternating period, such as square waves. A sample unit samples a third voltage on the third phase for acquiring a first sample at a first instant in the first part and a second sample at a second instant in the second part, and a difference value between the first sample and the second sample. The difference value represents a mutual inductance between the stator coils due to the rotor position. A determination unit determines the rotor position based on the difference value.