A novel motor controller controls a stepping motor and includes a command value calculator to calculate and output a speed command value and an angle command value based on a reference clock. A control method selector is included to select one of the open-loop control and the closed-loop control in accordance with the speed command value. A command value output unit is included to output a first target value as the first current command value when the open-loop control is selected and outputs a second target value as the second current command value when the closed-loop control is selected. The motor controller controls the stepping motor based on the first target value when the open-loop control is selected and the second target value when the closed-loop control is selected.

A novel motor controller controls a stepping motor and includes a command value calculator to calculate and output a speed command value and an angle command value based on a reference clock. A control method selector is included to select one of the open-loop control and the closed-loop control in accordance with the speed command value. A command value output unit is included to output a first target value as the first current command value when the open-loop control is selected and outputs a second target value as the second current command value when the closed-loop control is selected. The motor controller controls the stepping motor based on the first target value when the open-loop control is selected and the second target value when the closed-loop control is selected.

A motor drive control device includes a control unit monitoring a rotational state of a rotor of a two-phase stepping motor, setting an energization angle θ representing a magnitude of an electric angle for continuously energizing, of coils of two phases of the two-phase stepping motor, a coil of one phase in one direction based on the rotational state of the rotor, and generating a control signal Sd for controlling driving of the two-phase stepping motor based on the set energization angle θ, and a drive unit driving the coils of two phases based on the control signal Sd.

A motor drive control device includes a control unit monitoring a rotational state of a rotor of a two-phase stepping motor, setting an energization angle θ representing a magnitude of an electric angle for continuously energizing, of coils of two phases of the two-phase stepping motor, a coil of one phase in one direction based on the rotational state of the rotor, and generating a control signal Sd for controlling driving of the two-phase stepping motor based on the set energization angle θ, and a drive unit driving the coils of two phases based on the control signal Sd.

A system and method for reducing power consumption and increasing reliability in a solar tracking system is disclosed. The solar tracker comprises a panel, at least one actuator configured to control the orientation of the panel, and a tracking controller. The tracking controller is configured to determine a minimum operating current for the at least one actuator based on a range of motion of the panel, and energize the at least one actuator based on the minimum operating current. The tracking controller determines the minimum operating current based on the range of motion of the panel, specifically the minimum current need to drive the panel through a measured range of motion equal to or substantial similar to the full mechanical range of motion of the panel. Based on the minimum operating current, solar tracker may generate messages to repair or replace an actuator or gearbox, for example.

A system and method for reducing power consumption and increasing reliability in a solar tracking system is disclosed. The solar tracker comprises a panel, at least one actuator configured to control the orientation of the panel, and a tracking controller. The tracking controller is configured to determine a minimum operating current for the at least one actuator based on a range of motion of the panel, and energize the at least one actuator based on the minimum operating current. The tracking controller determines the minimum operating current based on the range of motion of the panel, specifically the minimum current need to drive the panel through a measured range of motion equal to or substantial similar to the full mechanical range of motion of the panel. Based on the minimum operating current, solar tracker may generate messages to repair or replace an actuator or gearbox, for example.

A method for controlling a stepper motor includes calculating a duty cycle of a current provided to the stepper motor and comparing a difference, between the calculated duty cycle and a base duty cycle of current provided to the stepper motor under a base load condition, to a reference duty cycle value. The method also includes adjusting a peak current level of the current provided to the stepper motor responsive to the comparison.

A method for controlling a polyphase actuator includes supplying each phase with a periodically varying voltage having a periodic sequence of steps P.sub.i that have a constant duration and an amplitude A.sub.n,i, where n corresponds to the rank of the phase and i to the rank of the step. The method further includes determining a target position PC.sub.i of a rotor of the actuator, in order to define a sinusoidal voltage envelope. The actuator further includes a movable member, a stator equipped with electrical coils and a sensor detecting the mechanical position of the movable member with respect to the stator, as well as a microcontroller. The microcontroller determines, at times T.sub.capteur, a mechanical position of a mechanical member, the microcontroller calculates, at each of the times T.sub.capteur, a difference between the mechanical position and a target position PC.sub.i corresponding to the step P.sub.i and the microcontroller calculates a coefficient k as a function of the difference. The microcontroller also weights the amplitude of a power supply applied to the phases by a coefficient k in order to supply the phases with weighted amplitude voltages A.sub.n,i*k.

A method for controlling a polyphase actuator includes supplying each phase with a periodically varying voltage having a periodic sequence of steps P.sub.i that have a constant duration and an amplitude A.sub.n,i, where n corresponds to the rank of the phase and i to the rank of the step. The method further includes determining a target position PC.sub.i of a rotor of the actuator, in order to define a sinusoidal voltage envelope. The actuator further includes a movable member, a stator equipped with electrical coils and a sensor detecting the mechanical position of the movable member with respect to the stator, as well as a microcontroller. The microcontroller determines, at times T.sub.capteur, a mechanical position of a mechanical member, the microcontroller calculates, at each of the times T.sub.capteur, a difference between the mechanical position and a target position PC.sub.i corresponding to the step P.sub.i and the microcontroller calculates a coefficient k as a function of the difference. The microcontroller also weights the amplitude of a power supply applied to the phases by a coefficient k in order to supply the phases with weighted amplitude voltages A.sub.n,i*k.

Excitation position is changed in accordance with an external clock. The state of a full bridge circuit including four transistors connected to a coil of a stepping motor, is controlled in accordance with the excitation position. At the time of transition from the excitation position at which coil current that flows in the coil is nonzero to the excitation position at which the coil current is zero, a switch is made to (i) the inverse state where the on or off state of each of the four transistors before the transition is inverted, and then a switch is made to (ii) the off state where all the four transistors are off.