A system may include an inverter configured to convert a direct current (DC) voltage to an alternating current (AC) voltage. The system may also include a control system communicatively coupled to the inverter. The control system may receive a torque current feedback from a motor and may generate, based on the torque current feedback, a command torque current and a command flux current. The control system may generate, based on the command torque current and the command flux current, a command torque voltage and a command flux voltage and may generate, based on a slip frequency and a rotor frequency, a command frequency. The control system may determine one or more operating parameters for the inverter based on the command frequency, the command torque voltage, and the command flux voltage and may control the inverter based on the one or more operating parameters.

A motor control method is provided. The method includes: receiving a plurality of voltage control signals from a rotation speed controller to output a plurality of PWM signals; receiving the plurality of PWM signals to output three phase currents, so that a motor rotates; sensing three phase current values of the three phase currents; directly calculating a real rotor angle of the motor according to two of the three phase current values; and adjusting the plurality of the outputted voltage control signals according to an expected rotor speed and the calculated real rotor angle, so as to make the real rotor speed of the motor reach the expected rotor speed.

A motor control method is provided. The method includes: receiving a plurality of voltage control signals from a rotation speed controller to output a plurality of PWM signals; receiving the plurality of PWM signals to output three phase currents, so that a motor rotates; sensing three phase current values of the three phase currents; directly calculating a real rotor angle of the motor according to two of the three phase current values; and adjusting the plurality of the outputted voltage control signals according to an expected rotor speed and the calculated real rotor angle, so as to make the real rotor speed of the motor reach the expected rotor speed.

Provided is an evaluation device that determines the necessity of a notch filter inserted in a control system that controls an electric motor by closed loop control. The evaluation device includes: a characteristic acquisition parts for changing a parameter associated with a characteristic of the notch filter from a first value, which is a prescribed value, to a second value, and acquiring a change in a frequency response characteristic of the electric motor when the notch filter is applied; and a determination parts for determining the necessity of the notch filter based on the change in the frequency response characteristic that has been acquired.

Provided is an evaluation device that determines the necessity of a notch filter inserted in a control system that controls an electric motor by closed loop control. The evaluation device includes: a characteristic acquisition parts for changing a parameter associated with a characteristic of the notch filter from a first value, which is a prescribed value, to a second value, and acquiring a change in a frequency response characteristic of the electric motor when the notch filter is applied; and a determination parts for determining the necessity of the notch filter based on the change in the frequency response characteristic that has been acquired.

A lead angle estimator is provided for estimating a lead angle of a brushless DC motor. The lead angle is the angle between a phase-voltage-vector of a phase-voltage, and a phase-current-vector of a phase-current. The lead angle estimator comprises a sampling unit and a processing unit. The sampling unit is adapted for obtaining phase-samples, which are a measure of the phase-current. The processing unit is adapted for estimating the lead angle by calculating a difference of the phase-samples in a extremum period around a maximum or around at least the phase-voltage, and by normalizing the obtained difference.

A lead angle estimator is provided for estimating a lead angle of a brushless DC motor. The lead angle is the angle between a phase-voltage-vector of a phase-voltage, and a phase-current-vector of a phase-current. The lead angle estimator comprises a sampling unit and a processing unit. The sampling unit is adapted for obtaining phase-samples, which are a measure of the phase-current. The processing unit is adapted for estimating the lead angle by calculating a difference of the phase-samples in a extremum period around a maximum or around at least the phase-voltage, and by normalizing the obtained difference.

An elevator drive system (40) includes a permanent magnet (PM) synchronous electric motor (34) including a plurality of phases and a plurality of motor drives (55, 58) electrically connected to the PM synchronous electric motor. Each of the plurality of motor drives is operatively connected to a corresponding one of the plurality of phases. The plurality of motor drives is configured and disposed to deliver a torque current divided equally between each of the plurality of phases and independently deliver flux current to the corresponding one of the plurality of phases.

An elevator drive system (40) includes a permanent magnet (PM) synchronous electric motor (34) including a plurality of phases and a plurality of motor drives (55, 58) electrically connected to the PM synchronous electric motor. Each of the plurality of motor drives is operatively connected to a corresponding one of the plurality of phases. The plurality of motor drives is configured and disposed to deliver a torque current divided equally between each of the plurality of phases and independently deliver flux current to the corresponding one of the plurality of phases.

A propulsion system having an electric motor and corresponding method. A controller is configured to receive a torque request and selectively command the electric motor. The controller has a processor and tangible, non-transitory memory on which instructions are recorded for a method of generating an auxiliary power. The controller is configured to obtain a desired auxiliary power and a delta factor (δ). The delta factor is set as a speed modifier (Δω=δ) when the cosine of an angle (θ), between a constant torque unit vector and a decreasing voltage ellipse unit vector, is less than a predefined threshold. A modified rotor speed is obtained as a sum of an original rotor speed and a speed modifier (Δω). The controller is configured to obtain modified stator current commands based on the modified rotor speed and torque request. The auxiliary power is generated by commanding the modified stator current commands.