A device or method for stabilizing a voice coil is disclosed. The device comprises a voice coil for providing a motive force, and means for measuring a signal from said voice coil related to a motional electromotive force. The device further comprises a unit for controlling an amplification of said signal to create a force in said voice coil in a direction of said motional electromotive force.

The present invention provides a motor driving circuit to reduce switching loss, which is applied to a motor. The motor driving circuit comprises a motor driving unit, a push-pull output unit, and a control unit. The control unit is coupled to the motor driving unit and the push-pull output unit. The control unit transmits a driving voltage to drive the push-pull output unit such that the push-pull output unit generates amplified currents which are transmitted to the motor driving unit. The motor driving unit reduces charge/discharge periods thereof based on the received amplified currents.

A work machine includes: a controller; a first electrical circuit provided with a first power supply that supplies power to the controller; an electric drive source necessary for operating the work machine; and a second electrical circuit provided with a second power supply that supplies power to the electric drive source. The work machine further includes: a capacitor provided to the second electrical circuit; a first precharge device that performs precharge of the capacitor by using power of the first power supply; and a second precharge device that performs precharge of the capacitor by using power of the second power supply. The controller performs precharge by using one of the precharge devices when it is determined that precharge by using the other one of the precharge devices is impossible.

A method for driving first and second voice coil motors (VCMs) by generating a first coil current through the first VCM and routing a portion (not all) of the first coil current through the second VCM when a first VCM movement command is commanding greater movement than a second VCM movement command. A second coil current is generated through the second VCM and a portion (not all) of the second coil current is routed through the first VCM, when the first VCM movement command is commanding smaller movement than the second VCM movement command. This may reduce power consumption. Other embodiments are also described and claimed.

In some embodiments, the method includes measuring a first responsive voltage value for a first voltage drop between a first terminal attached to a first suspension spring of an actuator housing a voice coil motor for moving a lens assembly and a second terminal of the magnetic coil of the voice coil motor. In some embodiments, the method includes calculating a first resistance of the magnetic coil based at least in part upon the first voltage value and measuring a second responsive voltage value for a second voltage drop between the first terminal attached and the second terminal. In some embodiments, the method includes calculating a second resistance of the magnetic coil based at least in part upon the second responsive voltage value and calculating a relative temperature for the magnetic coil based at least in part upon the first resistance and the second resistance.

In some embodiments, the method includes measuring a first responsive voltage value for a first voltage drop between a first terminal attached to a first suspension spring of an actuator housing a voice coil motor for moving a lens assembly and a second terminal of the magnetic coil of the voice coil motor. In some embodiments, the method includes calculating a first resistance of the magnetic coil based at least in part upon the first voltage value and measuring a second responsive voltage value for a second voltage drop between the first terminal attached and the second terminal. In some embodiments, the method includes calculating a second resistance of the magnetic coil based at least in part upon the second responsive voltage value and calculating a relative temperature for the magnetic coil based at least in part upon the first resistance and the second resistance.

Disclosed herein are a motor control device and a motor control method. The motor control method receiving a torque command to control a motor and generating a reference current includes calculating maximum torque of the motor based on the torque command, determining whether the calculated maximum torque exceeds a torque limit, and calculating maximum torque per unit current, when the calculated maximum torque does not exceed the torque limit.

Disclosed herein are a motor control device and a motor control method. The motor control method receiving a torque command to control a motor and generating a reference current includes calculating maximum torque of the motor based on the torque command, determining whether the calculated maximum torque exceeds a torque limit, and calculating maximum torque per unit current, when the calculated maximum torque does not exceed the torque limit.

A motor control device includes: a current control unit that calculates a voltage command with respect to a d-axis and a q-axis of a motor at every predetermined calculation cycle; a carrier wave generation unit that generates a carrier wave; a carrier wave frequency adjustment unit that adjusts a frequency of the carrier wave; a phase calculation unit that calculates a voltage phase of an inverter based on a rotation position of the motor; a divided phase calculation unit that calculates a divided phase in which the voltage phase is divided for every predetermined division number of two or more; a three-phase voltage conversion unit that converts the voltage command into a three-phase voltage command based on the divided phase; and a PWM control unit that performs pulse width modulation on the three-phase voltage command using the carrier wave and generates a PWM pulse signal for controlling operation of the inverter.

A motor control device includes: a current control unit that calculates a voltage command with respect to a d-axis and a q-axis of a motor at every predetermined calculation cycle; a carrier wave generation unit that generates a carrier wave; a carrier wave frequency adjustment unit that adjusts a frequency of the carrier wave; a phase calculation unit that calculates a voltage phase of an inverter based on a rotation position of the motor; a divided phase calculation unit that calculates a divided phase in which the voltage phase is divided for every predetermined division number of two or more; a three-phase voltage conversion unit that converts the voltage command into a three-phase voltage command based on the divided phase; and a PWM control unit that performs pulse width modulation on the three-phase voltage command using the carrier wave and generates a PWM pulse signal for controlling operation of the inverter.