Provided is a motor driving apparatus including: an upper-arm gate driving circuit; a lower-arm gate driving circuit; a first rotation detection unit powered by a first power source; a second rotation detection unit powered by a second power source; a first fail safe circuit that performs, by use of a detection signal from the first rotation detection unit, a fail safe control on a gate driving circuit powered at least by the first power source, from among the upper-arm gate driving circuit and the lower-arm gate driving circuit; and a second fail safe circuit that performs, by use of a detection signal from the second rotation detection unit, a fail safe control on a gate driving circuit powered at least by the second power source, from among the upper-arm gate driving circuit and the lower-arm gate driving circuit.

A voltage source inverter comprises a rectifier circuit having an input for connection to a multi-phase AC power source and converting the AC power to DC power and an inverter circuit for receiving DC power and converting the DC power to AC power. A DC bus circuit is connected between the rectifier circuit and the inverter circuit to provide a relatively fixed DC voltage for the inverter circuit, the DC bus circuit comprising a DC bus including a first bus rail comprising an inductor and a second bus rail, and a soft charge circuit connected in series with a DC bus capacitor network between the first and second rails, the DC bus capacitor network comprising a first capacitor branch including a pair of capacitors with a fuse connected in series between the capacitors, a balancing resistor across each capacitor and a snubbing capacitor connected across the fuse.

To avoid the catastrophic failure of a drive, protection circuitry is configured to limit current in the DC bus capacitors. The drive may include an isolation circuit and a protection circuit having a comparator. The protection circuit may be configured to compare the voltage measured across a DC bus capacitor with a threshold voltage and activate the isolation circuit when the DC capacitor voltage exceeds the threshold voltage. The drive may also include a low voltage circuit coupled to the isolation circuit, where the low voltage circuit is configured to interrupt the bypass signal to disengage the bypass circuit and activate the precharge circuit when the isolation circuit is activated. Accordingly, the current in the drive and to the DC bus capacitors is limited by the precharge circuit when the voltage of a capacitor in the DC bus exceeds a threshold.

An agricultural system includes a controller comprising a memory and a processor. The controller is configured to receive a sensor signal, determine a current flow based on the sensor signal, determine whether the current flow exceeds a current threshold for a time threshold, and operate a drive system of the agricultural system in an alternative operation instead of a normal operation in response to determining the current flow exceeds the current threshold for the time threshold.

Provided is an apparatus and method for protecting an overcurrent of a clutch control system including a motor, an inverter including a plurality of switching elements and configured to convert DC power into AC power by ON/OFF of the plurality of switching elements and to provide the AC power to the motor; a motor control unit configured to detect a current provided to the motor; and a microcomputer having an overcurrent threshold for overcurrent detection set for each of a predetermined number of levels, and configured to compare the detected current with the overcurrent threshold for each level, to diagnose whether there is a level corresponding to an overcurrent, to measure an overcurrent duration when there is a level corresponding to the overcurrent, and to control the inverter based on the overcurrent duration.

To provide a controller and a control method which can estimate a temperature of the temperature estimation with good accuracy without depending on detection information of other sensors other than the temperature sensor, even if the temperature sensor is attached to a position away from the temperature estimation point. A controller is provided with a sensor temperature detector that detects a sensor temperature based on an output signal of a temperature sensor attached to a temperature estimation object; and a temperature estimator that calculates an estimated temperature of the temperature estimation point, based on the current detection value of sensor temperature or the current correction value of sensor temperature, the detection value of sensor temperature before the step time or the correction value of sensor temperature before the step time, and a thermal time constant.

A load control apparatus (1) for controlling a power supply to an electrical load connected to an output terminal (3) of the load control apparatus (1) comprising: an overcurrent protection circuit (1A) having a power switch (5) through which the electrical load receives an electrical load current (I.sub.L) and having a sensor component (4) connected in series with the power switch (5) and adapted to generate directly a voltage drop (ΔU.sub.4) corresponding to the current rise speed of the electrical load current (I.sub.L) flowing from an input terminal (2) of the load control apparatus (1) via the sensor component (4) and the power switch (5) to the output terminal (3) and having a driver circuit (6) adapted to detect an occurring overcurrent depending on the voltage drop (ΔU.sub.4) generated by the sensor component (4) and/or a voltage drop (ΔU.sub.5) along the power switch (5) and adapted to switch off said power switch (5) upon detection of an overcurrent within a switch-off period of less than one millisecond; and/or comprising a power supply control circuit (1C) having a sensor component (9) adapted to measure at the input terminal (2) a supply voltage notified to a control unit (8) of the load control apparatus (1) adapted to control an electrical power supplied to the electrical load.

A load protection apparatus for protecting an electrical load connected to an output terminal (3) of the load protection apparatus (1) against overcurrent, said apparatus (1) comprising: an overcurrent protection circuit (1A) having a power switch (5) through which the electrical load receives an electrical load current (I.sub.L) via the output terminal (3) and having a sensor component (4) connected in series with the power switch (5) and adapted to generate directly a voltage drop (ΔU.sub.4) corresponding to the current rise speed of the electrical load current (I.sub.L) flowing from an input terminal (2) of the load control apparatus (1) via the sensor component (4) and the power switch (5) to the output terminal (3) and having a driver circuit (6) adapted to detect an occurring overcurrent depending on the voltage drop (ΔU.sub.4) generated by the sensor component (4) and depending on a voltage drop (ΔU.sub.5) along the power switch (5) adapted to switch off said power switch (5) upon detection of an overcurrent within a switch-off period.

An impact power tool includes a housing, a motor, a controller, an output member configured to be rotated when the motor is energized, and an impact mechanism configured to rotationally drive the output member. The impact mechanism is configured to selectively apply rotational impacts to the output member when a torque on the output member exceeds a torque threshold. The controller is configured to control the motor during a first phase of operation with open loop control and a baseline conduction band and advance angle setting when a sensed tool operation parameter is one of above or below a threshold value. The controller is configured to control the motor during a second phase of operation with closed speed loop control and an increased conduction band and advance angle setting when the sensed tool operation parameter is the other of above or below the threshold value.

An impact power tool includes a housing, a motor, a controller, an impact mechanism configured to be driven by the motor, and an output spindle configured to receive rotational impacts from the impact mechanism to rotate the output spindle. The controller is configured to detect a first impact of the rotational impacts or to detect when the motor speed drops below a speed threshold value. The controller is configured to control the motor to have a first non-zero target rotational speed using closed loop control for a predetermined time period after the first impact is detected or when the motor speed dropping below the speed threshold value is detected. The controller is configured to control the motor to have a second non-zero target rotational speed using the closed loop control after the predetermined time period. The first non-zero target rotational speed is less than the second non-zero target rotational speed.