A motor including: a stator including plural windings that form coils and are connected together at a neutral point; a switching circuit that generates a rotating magnetic field around the stator by switching of a power supply to the plurality of windings; a rotor that rotates in response to the rotating magnetic field generated around the stator; a resistor for current detection that detects a current in the switching circuit and that is disposed between the switching circuit and a grounding point; and a filter element that reduces a fluctuation in potential at the neutral point, the filter element being disposed between the neutral point and the resistor for current detection and being grounded at the grounding point via the resistor for current detection.

Selectable current limiting for a power tool. One embodiment provides a method for selectable current limiting for a power tool including determining, using a current sensor, an average current and determining whether the average current exceeds a predetermined current threshold. The method also includes determining a deviation of the average current from the predetermined current threshold and reducing a PWM duty ratio proportional to the deviation of the average current from the predetermined current threshold. The PWM duty ratio corresponds to a PWM signal provided to an inverter bridge.

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 power tool includes a housing having a motor housing portion and a handle portion. A motor having a motor axis is positioned within the motor housing portion. The power tool further includes a first printed circuit board positioned within the motor housing portion. The first printed circuit board intersects the motor axis. The power tool also includes a second printed circuit board positioned within the motor housing. The second printed circuit board intersects the motor axis. The second printed circuit board includes a conductive high impedance trace that is configured to interrupt electric power to the motor in response to a current that exceeds a current limit.

A system (1) has a control device (10) with central electronics (11) designed for connection and operation of differently coded electric motors (En), with different motor characteristics (Mn) and/or power classes (Ln), to a device connection (12) of the control device (10). The at least one electric motor (En) is selectable from a number (n) of electric motor (En), that can be connected as intended, has a coding element (Kn). The central electronics (11) have a coding capture device (2) to recognize, via coding element (n), the motor characteristics (Mn) and/or the power class (Ln) of the respective currently connected electric motor (En).

An electric power conversion device includes: a first electric power conversion circuit, a current detection circuit, an electric power conversion circuit of field coil excite use, a control circuit, and detector which detects an induced electromotive force generated in the motor generator. In a case where an over current, is detected by the first electric power conversion circuit, the control circuit turns off a switching of a phase of the first electric power conversion circuit from which an over current s detected and a switching of the electric power conversion circuit of field coil excite use. After the value of an induced electromotive force by the motor generator falls below a predetermined value, the control circuit controls to stop a supply of electric power of all phases by the first electric power conversion circuit.

A windshield wiper system (WWS) is provided. The WWS includes a brushless direct current (BLDC) motor, a wiper arm and blade, a gearbox/converter operably interposed between the BLDC motor and the wiper arm and blade and a smart motor drive configured to determine a WWS failure condition and to operate the BLDC motor according to the determination.

A control system has a microcontroller (242) that receives a mode request (MR), a command-generating device (244) to supply commands and to transfer the mode request (MS) to an output pin of the microcontroller (242), and a device for detecting accidental starting (258), as well as a pilot (260) that supplies an output command signal to the switch (222; 224). The pilot (260) is connected to the output pin to receive the transmitted mode request (MS). The output pin is connected to an input pin of the microcontroller (242) to receive the transmitted mode request (MS), and the accidental starting detection device (258) detects when the transmitted mode request (MS) received on the input pin indicates a motor mode even though the mode request (MR) received by the microcontroller (242) indicates an alternator mode and, when this is the case, sends an inhibition command (INHIB_P; INHIB_T) to the pilot (260).

An overcurrent protection circuit and a controller are provided. The overcurrent protection circuit includes a sampling circuit, a comparator circuit, a D flip-flop, and an output signal control circuit. The sampling circuit samples a current of a controlled circuit to obtain a sample signal. The comparator circuit compares the sample signal with a reference signal, and generates an overcurrent signal if the sample signal is greater than the reference signal. The D flip-flop generates a first level signal in response to the overcurrent signal. The output signal control circuit outputs, in response to the first level signal, a control signal for reducing the current of the controlled circuit. The controller includes a controlled circuit and the overcurrent protection circuit.

A motor drive system includes: an inverter that drives a motor; a current detector that detects and outputs the first signal that is a current value of a current flowing through the inverter; a first low-pass filter that removes a noise frequency component from the first signal and outputs a second signal that is a current value after the noise frequency component has been removed; a demagnetization current determiner that compares a demagnetization current threshold with the second signal, and outputs a demagnetization protection signal when the second signal takes a value larger than the demagnetization current threshold; and a short circuit determiner that compares a third signal with a short circuit and outputs an anomaly signal for stopping the inverter when the third signal takes a value larger than or equal to the short circuit threshold.