Examples of methods and systems for compensating for the timing delay caused by the winding impedance of the motor coils and/or for non-ideal rotor magnet shapes and positions are disclosed. The example methods and systems may include generating a synthesized commutation signal compensating for non-ideal magnet shapes and positions (e.g., asymmetrical magnet positions) on a rotor and/or compensates for the timing delay caused by the winding impedance of the motor coils.

A motor current protecting circuit is provided. A voltage calculating circuit determines whether or not each of low-side switches is fully turned on and then determines whether or not a voltage difference between a first terminal and a second terminal of each of the low-side switches being fully turned on is larger than or equal to a zero value. The voltage calculating circuit adds up the voltage differences each of which is larger than or equal to the zero value to output a voltage signal. A control circuit controls a driver circuit to switch the low-side switches and high-side switches according to the voltage signal.

A motor current protecting circuit is provided. A voltage calculating circuit determines whether or not each of low-side switches is fully turned on and then determines whether or not a voltage difference between a first terminal and a second terminal of each of the low-side switches being fully turned on is larger than or equal to a zero value. The voltage calculating circuit adds up the voltage differences each of which is larger than or equal to the zero value to output a voltage signal. A control circuit controls a driver circuit to switch the low-side switches and high-side switches according to the voltage signal.

The subject matter of this specification can be embodied in, among other things, an electric actuator driver that includes a first input port configured to receive an analog electrical servo control signal, a second input port configured to receive a position feedback signal, a first output port, a second output port, and a conversion circuit configured to determine one or more electric motor coil control current levels based on the analog electrical servo control signal and the position feedback signal, provide the one or more electric motor coil control currents based on the determined electric motor coil control current levels at the first output port, determine a feedback signal based on the analog electrical servo control signal, and provide the determined feedback signal at the second output port.

The subject matter of this specification can be embodied in, among other things, an electric actuator driver that includes a first input port configured to receive an analog electrical servo control signal, a second input port configured to receive a position feedback signal, a first output port, a second output port, and a conversion circuit configured to determine one or more electric motor coil control current levels based on the analog electrical servo control signal and the position feedback signal, provide the one or more electric motor coil control currents based on the determined electric motor coil control current levels at the first output port, determine a feedback signal based on the analog electrical servo control signal, and provide the determined feedback signal at the second output port.

Provided is an electronic timepiece capable of suppressing variation in the drive speed of a rotor, and driving a motor at a constant speed. The electronic timepiece has a driver; a controller that controls the driver to the on state or the off state according to a current flowing through a coil of a motor; a detection signal output device configured to output a detection signal when the on time or the off time, which are the continuous time of the on state and off state of the driver, meets a specific condition; a reference signal output device that outputs a reference signal used as a reference of a drive speed of the motor; and a drive cycle adjuster that compares the output timing of the detection signal and the reference signal, shortens the drive cycle when the detection signal is output after the reference signal, and when the detection signal is output before the reference signal, lengthens the drive cycle of the motor.

For polyharmonic flux motor loss increase, a method offsets pulse width modulation (PWM) carriers to a motor to increase motor harmonics. The offset PWM carriers increase energy losses for the motor.

For polyharmonic flux motor loss increase, a method offsets pulse width modulation (PWM) carriers to a motor to increase motor harmonics. The offset PWM carriers increase energy losses for the motor.

A current measuring system (10) for a commutated motor (20). The current measuring system comprises a bridge circuit (30) with several branches (30a-c), wherein the branches (30a-c) are in each case connected to commutation blocks of the commutated motor (20), and the branches (30a-c) each have a current measuring circuit (60a-c).

A current measuring system (10) for a commutated motor (20). The current measuring system comprises a bridge circuit (30) with several branches (30a-c), wherein the branches (30a-c) are in each case connected to commutation blocks of the commutated motor (20), and the branches (30a-c) each have a current measuring circuit (60a-c).