A power converter converts a medium-voltage output from a solar module to an appropriate voltage to power a solar tracker system. The power converter includes a voltage divider having at least two legs, a first semiconductor switch subassembly coupled in parallel with a first leg of the voltage divider, and a second semiconductor switch subassembly coupled in parallel with a second leg of the voltage divider. The power converter may be a unidirectional or a bidirectional power converter. In implementations, the signals for driving the semiconductor switches of the first and second semiconductor switch subassemblies may be shifted out of phase from each other. In implementations, if the bus voltages to the semiconductor switches are not balanced, the pulse width of the driving signal of the semiconductor switch supplied with the higher bus voltage is decreased for at least one cycle.

A power converter converts a medium-voltage output from a solar module to an appropriate voltage to power a solar tracker system. The power converter includes a voltage divider having at least two legs, a first semiconductor switch subassembly coupled in parallel with a first leg of the voltage divider, and a second semiconductor switch subassembly coupled in parallel with a second leg of the voltage divider. The power converter may be a unidirectional or a bidirectional power converter. In implementations, the signals for driving the semiconductor switches of the first and second semiconductor switch subassemblies may be shifted out of phase from each other. In implementations, if the bus voltages to the semiconductor switches are not balanced, the pulse width of the driving signal of the semiconductor switch supplied with the higher bus voltage is decreased for at least one cycle.

A motor control apparatus includes a detection unit configured to detect an actual rotation position of a motor, a control unit configured to provide position feedback control on the motor so that the detected actual rotation position sequentially approaches a plurality of target rotation positions, and a processing unit configured to perform, before the position feedback control starts, processing to make an initial position deviation fall within a predetermined range, the initial position deviation being a difference between the actual rotation position and a first target rotation position of the plurality of target rotation positions.

A power tool is provided including a brushless motor having a stator defining a plurality of phases, a rotor rotatable relative to the stator, and power terminals electrically connected to the phases of the motor. A power unit is provided including power switches. A control unit is interfaced with the power unit to output a drive signal to one or more of the motor switches to drive the phases of the motor over a series of sectors of the rotor rotation. The control unit is configured detect incorrect rotation of the rotor by applying a first series of voltage pulses to a present sector and a second series of voltage pulses to a previous sector, measuring motor currents associated with the first and second series of voltage pulses, and comparing corresponding motor current measurements to detect a transition from the present sector to the previous sector.

A motor including a first terminal and a second terminal to which a single-phase AC is input includes a third terminal, an AC/DC converter that converts a single-phase AC into a DC, an inverter that is PWM-controlled by a PWM signal to convert the DC into a three-phase AC, a controller that outputs a PWM signal to the inverter, and a detection circuit connected to the third terminal, in which the detection circuit outputs any one of a first detection signal, a second detection signal, and a third detection signal, and the controller outputs a PWM signal to be in a first rotation state when the detection circuit outputs the first detection signal, to be in a second rotation state when the detection circuit outputs the second detection signal, and to be in a third rotation state when the detection circuit outputs the third detection signal.

A motor including a first terminal and a second terminal to which a single-phase AC is input includes a third terminal, an AC/DC converter that converts a single-phase AC into a DC, an inverter that is PWM-controlled by a PWM signal to convert the DC into a three-phase AC, a controller that outputs a PWM signal to the inverter, and a detection circuit connected to the third terminal, in which the detection circuit outputs any one of a first detection signal, a second detection signal, and a third detection signal, and the controller outputs a PWM signal to be in a first rotation state when the detection circuit outputs the first detection signal, to be in a second rotation state when the detection circuit outputs the second detection signal, and to be in a third rotation state when the detection circuit outputs the third detection signal.

A control module for a reversing contactor includes a housing configured to mount to forward and reverse contactors. The control module is configured to receive command signals for the forward and reverse contactors and provide the command signals to an interlock circuit included within the housing of the control module. The interlock circuit is configured to use the forward and reverse commands as well as feedback signals corresponding to the current status of the contactors to prevent both the forward and reverse contactors from being closed in tandem. The control module is also configured to mount to contactors having different physical sizes. The housing may be configured as a telescoping housing, where one portion of the housing is fixed and a second portion of the housing slides with respect to the fixed portion of the housing to adjust the width of the control module.

A control unit for a brushless DC motor of a power tool having a rotor and a stator is provided. The control unit detects an initial position of the rotor, commutates the motor beginning at the initial position of the rotor using a low-speed motor commutation scheme until an output speed of the rotor exceeds a speed threshold, and commutates the motor based on a back-electromotive force (back-EMF) voltage of the motor after the output speed of the rotor exceeds the speed threshold. In the low-speed commutation scheme, the control unit applies a first set of voltage pulses to a present sector and a second set of voltage pulses to a next sector, and detects a transition of the rotor from the present sector to the next sector based on motor current measurements associated with the first set of voltage pulses and the second set of voltage pulses.

A control unit for a brushless DC motor of a power tool having a rotor and a stator is provided. The control unit detects an initial position of the rotor, commutates the motor beginning at the initial position of the rotor using a low-speed motor commutation scheme until an output speed of the rotor exceeds a speed threshold, and commutates the motor based on a back-electromotive force (back-EMF) voltage of the motor after the output speed of the rotor exceeds the speed threshold. In the low-speed commutation scheme, the control unit applies a first set of voltage pulses to a present sector and a second set of voltage pulses to a next sector, and detects a transition of the rotor from the present sector to the next sector based on motor current measurements associated with the first set of voltage pulses and the second set of voltage pulses.

An assembly for extending and retracting an elongated peripheral device with respect to a supporting surface of a marine vessel includes a housing and an arm pivotably coupled to the housing. An electric motor is located in the housing and has an output shaft coupled to the arm. The electric motor changes an orientation of the housing and the arm with respect to one another. A mount coupled to the housing supports the peripheral device. As the electric motor changes the orientation of the housing and the arm with respect to one another, the mount and the peripheral device are simultaneously extended or retracted with respect to the supporting surface. A controller varies the power provided to the electric motor in response to determining that the peripheral device has encountered an obstacle while being extended or retracted with respect to the supporting surface.