In an embodiment of a system for closed-loop control of a linear resonant actuator, a system processor coupled to a magnetic field sensor is configured to: receive a magnetic field sensor signal from a channel coupling a magnetic field sensor and the system processor; receive measurements of actuator current and actuator voltage from drive electronics; receive a temperature signal from a linear resonant actuator, the temperature signal indicating a temperature of the magnetic field sensor; calculate a first estimate of mass position using the magnetic field sensor signal, actuator current and a magnetic model; calculate an estimate of coil resistance based on the temperature signal, the actuator current, the actuator voltage and a thermal model; and calculate a second estimate of mass position and an estimate of mass velocity based on the first estimate of mass position, the actuator current, the actuator voltage and the estimated coil resistance.

A brushless motor device including: a rotor; a stator including a first coil, a second coil and a third coil, first ends of which are Y-connected to each other; a motor driver including an inverter circuit including switching elements and configured to: switch ON and OFF states of each switching element of the inverter circuit, wherein by switching the ON and OFF states of each switching element of the inverter circuit, the motor driver is configured to switch an energization time period from a first time period in which current is caused to flow from the first coil to the third coil to a second time period in which current is caused to flow from the second coil to the third coil and set both voltages of second ends of the second coil and the third coil to a power supply voltage during the second time period.

A brushless motor device configured to: determine a first upper limit of a current value which flows through a coil when a rotation speed of a rotor is accelerated from a first speed to a second speed, wherein, in a case where the current value of the first upper limit flows through the coil when the rotor is rotated at the second speed, a first time period, which is from a start of a non-energization time period of the coil until an induced voltage reaches a threshold value, is longer than a second time period, which is from the start of the non-energization time period until a counter-electromotive voltage becomes zero; and change switching of each switching element of an inverter circuit by using a second upper limit greater than the first upper limit and the first upper limit.

A method for determining a position of a rotor of a brushless direct current (BLDC) motor at standstill. The method includes providing a plurality of current pulses to a plurality of windings of the BLDC motor while the rotor of the BLDC motor is at a standstill position. The method further includes measuring a plurality of times that it takes for the plurality of current pulses to reach a threshold for respective ones of the plurality of windings. A first position corresponding to a shortest time of the plurality of times is determined. A position detection value is determined based on the shortest time and based on times corresponding to positions that are adjacent to the first position. A position of the rotor at the standstill position is determined based on the position detection value and an interpolation function.

A field oriented control (FOC) system and method provides smooth field-oriented startup for three-phase sensorless permanent magnet synchronous motors (PMSMs) despite the absence of load information. The system uses the rotor flux projection on the d- or q-axis to determine whether the stator flux current reference being applied during reference startup phase is sufficient to spin the PMSM, thereby providing smooth operation during the reference startup phase and saving energy relative to applying rated current. The system also determines a suitable initial value for the stator torque current reference to use at the start of closed-loop sensorless FOC control mode based on an angle difference between the reference and estimated angles. Since this angle difference is reflective of the load on the PMSM, the selected initial value allows the system to achieve a smooth transition from reference startup mode to closed-loop sensorless FOC control mode.

A control device for a switched reluctance motor includes an inverter having a switching circuit that switches a magnetic pole to provide a first winding pattern or a second winding pattern. With respect to a boundary dividing a driving range of the switched reluctance motor into two ranges, the control device performs switching to the first winding pattern when the torque and the rotational speed are located in the first range on the low load side, performs switching to the second winding pattern when the torque and the rotational speed are located in the second range, allows switching of the magnetic pole in a case where a current of the phase whose magnetic pole is to be switched among the three-phase coils is 0, and prohibits switching of the magnetic pole in a case where the current of the phase whose magnetic pole is to be switched is not 0.

A circuit includes a processor that analyzes a pulse width modulated (PWM) signal feedback from a brushless DC motor to determine a transition between a mutual inductance zero crossing condition and a Back Electro Motive Force (BEMF) zero crossing condition of the brushless DC motor. A mutual inductance controller is executed by the processor to commutate the brushless DC motor at startup of the motor when the mutual inductance zero crossing condition is detected by the processor. A BEMF controller is executed by the processor to commutate the brushless DC motor after startup of the motor when the BEMF zero crossing condition is detected by the processor.

A control system for monitoring operation of an electric motor includes a plurality of position sensors configured to measure a position of the electric motor, an indirect position estimation module configured to indirectly estimate the position of the motor, and an error monitoring module. The error monitoring module is configured to perform at least one of: comparing a measured position from the plurality of position sensors to an estimated position from the sensor position estimation module, and detecting a failure of at least one of the one or more position sensors based on the comparison; and calculating a difference between the measured position from one of the plurality of position sensors and the measured position from another of the plurality of position sensors, and causing the indirect position estimation module to initiate estimation of the position of the motor based on the difference.

A field oriented control (FOC) system and method provides smooth field-oriented startup for three-phase sensorless permanent magnet synchronous motors (PMSMs) despite the absence of load information. The system uses the rotor flux projection on the d- or q-axis to determine whether the stator flux current reference being applied during reference startup phase is sufficient to spin the PMSM, thereby providing smooth operation during the reference startup phase and saving energy relative to applying rated current. The system also determines a suitable initial value for the stator torque current reference to use at the start of closed-loop sensorless FOC control mode based on an angle difference between the reference and estimated angles. Since this angle difference is reflective of the load on the PMSM, the selected initial value allows the system to achieve a smooth transition from reference startup mode to closed-loop sensorless FOC control mode.

A control device for a switched reluctance motor includes an inverter having a switching circuit that switches a magnetic pole to provide a first winding pattern or a second winding pattern. With respect to a boundary dividing a driving range of the switched reluctance motor into two ranges, the control device performs switching to the first winding pattern when the torque and the rotational speed are located in the first range on the low load side, performs switching to the second winding pattern when the torque and the rotational speed are located in the second range, allows switching of the magnetic pole in a case where a current of the phase whose magnetic pole is to be switched among the three-phase coils is 0, and prohibits switching of the magnetic pole in a case where the current of the phase whose magnetic pole is to be switched is not 0.