Examples include a variable speed drive and method for controlling such variable speed drive driving an electric motor. The variable speed drive includes an inverter and is able to detect when a specific component (IGBT or freewheeling diode) of a specific switch of the inverter crosses a predetermined voltage threshold. An example method allows determining a state of a specific component based on the detection of the crossing.

A control circuit of an electric motor includes a filtering device in order to filter high frequencies likely to produce perturbing electromagnetic radiation when the electric motor is driven. To this end, the filtering device includes one or more filtering capacitors branched off from a power bridge driving the electric motor, wherein at least a proportion of the filtering capacitors is of a polymer-hybrid type in order to improve dynamic performance of the filtering device and to reduce its size. A motorized-fan unit for motor vehicles including such a control circuit is also disclosed.

A power tool has a functional component, a motor, a power supply module, a controller and a drive circuit including a first drive terminal and a second drive terminal respectively electrically connected to a first power terminal and a second power terminal of the power supply module, multiple high-side switches wherein high-side terminals of the high-side switches are respectively electrically connected to the first drive terminal, and multiple low-side switches wherein low-side terminals of the low-side switches are respectively electrically connected to the second drive terminal. The controller is configured to output a first control signal to one high-side switch to place it in an on or off state and output a second control signal to one low-side switch to place it in the other state. The low-side terminal of one high-side switch is connected to the high-side terminal of one low-side switch.

A motor current controlling circuit having a voltage detection mechanism is provided. A first terminal of a first low-side transistor is connected to a second terminal of a first high-side transistor. A node between the first terminal of the first low-side transistor and the second terminal of the first high-side transistor is connected to a first terminal of a motor. A first terminal of a second low-side transistor is connected to a second terminal of a second high-side transistor. A zero current detector circuit detects a voltage of the node and determines whether or not a current flowing through the motor is equal to a zero value to output a zero current detected signal according to the detected voltage. A controller circuit controls a driver circuit to turn on or off the high-side transistors and the low-side transistors according to the zero current detected signal.

A motor unit having a motor having a stator and an armature, the armature being arranged for relative driven motion with respect to the stator. A motor control unit has a supply circuit for providing a supply voltage at the motor to provide a set power level to the motor for driving the armature into motion. A measurement circuit is measuring a value of a physical variable indicative of a current flow through the motor, The motor control unit is arranged to interrupt the provision of the supply voltage by the supply circuit and to dynamically brake the motor during a braking time interval and further to measure the value of the physical variable during the braking time interval. The motor control unit is further arranged to compare the measured value of the physical variable with a target value that depends on the supplied power level and on an intended motion amplitude of the armature, to determine a new set power level in dependence on the comparison result and to subsequently provide the new set power level to the motor.

A windshield wiper system includes a three-phase motor, the three-phase inverter, a brake circuit, and a controller. The controller transmits commutation signals to the three-phase inverter to drive the motor according to an inboard-to-outboard speed profile and to drive the motor according to an outboard-to-inboard speed profile. The controller activates the brake circuit based on the inboard-to outboard speed profile, or the outboard-to-inboard speed profile, and a direct current bus voltage.

A three-phase brushless motor control device uses one shunt resistor disposed on a bus of an inverter as a drive circuit driving a three-phase brushless motor and acquires a two-phase current of the three-phase brushless motor at a predetermined timing to vector-control the three-phase brushless motor. At this time, in accordance with a duration in which the two-phase current cannot be accurately acquired, the control device varies an acquisition timing of the two-phase current or varies a period during which the three-phase brushless motor is vector-controlled.

In a two-phase modulation type three-phase inverter control method having a pause section in which a pulse signal obtained by comparing a modulated wave signal for driving a motor and a carrier signal is not output, a pulse signal generation unit switches a first carrier signal to a second carrier signal when an electric angle of the motor is within the pause section for each of three phases.

A device for driving a closure component (9) in a building from a solar energy source (1), comprising at least one low-voltage alternating current electric motor (3) mechanically coupled to the closure component, a direct current electrical energy accumulator element (2), a solar energy source delivering a direct voltage. The electrical energy accumulator element has a nominal voltage lower than said effective electric voltage and greater than the direct voltage delivered by the solar energy source. A DC-DC charger (4) converts the output electrical energy from the solar energy source into electrical energy with an electric voltage for charging the electrical energy accumulator element. A DC-AC converter (5) converts the electrical energy with a direct output voltage of the electrical energy accumulator element into electrical energy with an alternating voltage that is able to power said electric motor.

A controller of a power tool outputs a driving signal to a motor driving circuit and acquires a position of a rotor of a brushless motor. While acquiring the position of the rotor of the brushless motor, a phase voltage or a line voltage of a winding of the brushless motor is detected through the voltage detection circuit. Whether an upper bridge arm switching element, a lower bridge arm switching element, and/or the brushless motor is short-circuited is determined according to the phase voltage or the line voltage of the winding of the brushless motor.