Systems, devices, and methods for: an unmanned aerial vehicle (UAV); at least one sensorless motor of the UAV, the at least one sensorless motor comprising a set of windings and a rotor; at least one propeller connected to the at least one sensorless motor; a microcontroller in communication with the at least one sensorless motor, wherein the microcontroller is configured to: determine a rotation rate of the at least one propeller; determine a rotation direction of the at least one propeller; provide an output to stop the at least one propeller if at least one of: the determined rotation rate is not a desired rotation rate and the determined rotation direction is not a desired rotation direction; and provide an output to start the at least one propeller if the at least one propeller is stopped at the desired rotation rate and the desired rotation direction.

Systems, devices, and methods for: an unmanned aerial vehicle (UAV); at least one sensorless motor of the UAV, the at least one sensorless motor comprising a set of windings and a rotor; at least one propeller connected to the at least one sensorless motor; a microcontroller in communication with the at least one sensorless motor, wherein the microcontroller is configured to: determine a rotation rate of the at least one propeller; determine a rotation direction of the at least one propeller; provide an output to stop the at least one propeller if at least one of: the determined rotation rate is not a desired rotation rate and the determined rotation direction is not a desired rotation direction; and provide an output to start the at least one propeller if the at least one propeller is stopped at the desired rotation rate and the desired rotation direction.

An air conditioning system includes a compressor including a motor, a condenser, and an evaporator; a drive including an inverter providing a multiphase, AC output voltage to the motor; a current sensor configured to sense an output current generated by the inverter; a controller configured to communicate with the current sensor and the inverter, the controller configured to provide a voltage command to the inverter, the controller configured to execute operations including: monitor the output current generated by the inverter; compare the output current to a threshold; determine the occurrence of an over current condition when the output current exceeds the threshold; when an over current condition is detected, reducing the voltage command to the inverter.

A method is provided for electrically driving a motor having a plurality of phase windings such that EMC (electromagnetic compatibility) is improved and the running performance of the motor is simultaneously kept constant. At least one of the phase windings is not supplied with a current pulse during a complete revolution of the rotor, or at least one switchable electrical resistor is switched on, for at least one subsequent commutation phase by means of an electrical switching element, if the detected rotor speed is greater than the specified target speed.

Provided is a method for determining the rotational position of a rotor in a permanent magnet synchronous machine, wherein the stator includes windings for a first, second and third phase, including the steps: applying a first voltage pulse to the first phase, determining respective first measures for the current induced by the first voltage pulse in the second and third phase, selecting a first selected phase depending on the first measures for the current, wherein the first selected phase is either the second or the third phase, applying a second voltage pulse to the first selected phase, determining respective second measures for the current induced by the second voltage pulse in the phases of the stator that are not the first selected phase, and determining the rotational position of the rotor depending on the second measures of the current.

Provided is a method for determining the rotational position of a rotor in a permanent magnet synchronous machine, wherein the stator includes windings for a first, second and third phase, including the steps: applying a first voltage pulse to the first phase, determining respective first measures for the current induced by the first voltage pulse in the second and third phase, selecting a first selected phase depending on the first measures for the current, wherein the first selected phase is either the second or the third phase, applying a second voltage pulse to the first selected phase, determining respective second measures for the current induced by the second voltage pulse in the phases of the stator that are not the first selected phase, and determining the rotational position of the rotor depending on the second measures of the current.

A method for starting a synchronous motor is provided. The synchronous motor includes a rotor for creating a first magnetic field and a stator with stator windings connected to an electrical energy converter for converting a supply voltage into a stator voltage to be applied to the stator windings to create a rotating second magnetic field interacting with the first magnetic field. The method includes applying reference stator voltages to the stator windings, where the reference stator voltages are determined from a reference current vector and a reference rotor speed, measuring stator currents, calculating an estimated rotor speed and rotor position from the applied stator voltages and the measured stator currents, calculating a speed error by subtracting the estimated rotor speed from the reference rotor speed, determining a reference torque producing current component from the speed error, and modifying the reference current vector with the reference torque producing current component.

A method for starting a synchronous motor is provided. The synchronous motor includes a rotor for creating a first magnetic field and a stator with stator windings connected to an electrical energy converter for converting a supply voltage into a stator voltage to be applied to the stator windings to create a rotating second magnetic field interacting with the first magnetic field. The method includes applying reference stator voltages to the stator windings, where the reference stator voltages are determined from a reference current vector and a reference rotor speed, measuring stator currents, calculating an estimated rotor speed and rotor position from the applied stator voltages and the measured stator currents, calculating a speed error by subtracting the estimated rotor speed from the reference rotor speed, determining a reference torque producing current component from the speed error, and modifying the reference current vector with the reference torque producing current component.

A power converter is configured to measure an output current and to determine a multi-phase voltage reference as a function of the output current. Within the same switching period the voltage reference is determined, a modulation routine determines a modulation index for each phase of the output voltage. In some instances, one or more phases must start modulation during the switching period before the new modulation index is determined. The modulation routine stores the value of the modulation index generated from the prior switching period and uses the stored value when a new value is not yet ready. An offset value for the phase voltage which used a modulation index from the prior switching period is determined in order to compensate the phase voltages of the other phases and to maintain a desired line-to-line voltage output from the power converter.

A power converter is configured to measure an output current and to determine a multi-phase voltage reference as a function of the output current. Within the same switching period the voltage reference is determined, a modulation routine determines a modulation index for each phase of the output voltage. In some instances, one or more phases must start modulation during the switching period before the new modulation index is determined. The modulation routine stores the value of the modulation index generated from the prior switching period and uses the stored value when a new value is not yet ready. An offset value for the phase voltage which used a modulation index from the prior switching period is determined in order to compensate the phase voltages of the other phases and to maintain a desired line-to-line voltage output from the power converter.