A signal transmission device that transmits a driving signal for a power transistor from a primary circuit system to a secondary circuit system while isolating between the primary and secondary circuit systems includes; a first fault detection circuit configured to detect a fault in the primary circuit system; a second fault detection circuit configured to detect a fault in the secondary circuit system; a first signal transmission path configured to transmit the result of detection by the second fault detection circuit from the secondary circuit system to the primary circuit system while isolating between the primary and secondary circuit systems; and a self-test circuit configured to perform a self-test on each of the first fault detection circuit, the second fault detection circuit, and the first signal transmission path.

A method includes receiving first and second output signals from a proportional-integral-derivative (PID) regulator circuit, wherein the first and second output signals represent three-phase currents provided into a machine. The method further includes determining a fault detection signal based on the first and second output signals. The method also includes comparing the fault detection signal to a threshold; and detecting a fault in the machine based on the fault detection signal exceeding the threshold.

An overvoltage protecting system and method of a motor pre-driver are provided. An overvoltage protecting circuit compares a first reference voltage with a common voltage inputted to a single phase motor to output a first comparison signal. When a controller circuit determines that the common voltage is higher than the first reference voltage according to the first comparison signal, the controller circuit turns off a first high-side switch and a second high-side switch, and turns on the first low-side switch and the second low-side switch, during a phase time of a phase transition signal of the single phase motor. After the phase time ends, the controller circuit alternately turns on the first low-side switch and the second low-side switch according to a level of the phase transition signal.

An electric motor control device includes an inverter circuit, which has a power conversion circuit configured of six switching elements, and a switching control circuit that controls the switching elements in such a way as to be turned on or off, wherein, when it is determined that the inverter circuit is in an abnormal state, an execution of a three-phase short-circuiting process, whereby all upper side switching elements or all lower side switching elements are turned on, or a six-switch opening process, whereby all the switching elements are turned off, is selected based on a temperature of at least one permanent magnet of an electric motor, in accordance with an operating state of the electric motor.

A power tool is provided including a power supply interface receiving a medium-voltage-rated removable battery pack having a maximum rated voltage in the range of 40 to 80 volts, and a brushless direct current (BLDC) motor. The motor includes a rotor and a stator having at least three stator windings corresponding to at least three phases of the motor, the rotor being moveable by the stator when the stator windings are appropriately energized within the corresponding phases. A multi-phase inverter bridge circuit is disposed between the power supply interface and the motor, and a controller is configured to output drive signals to the inverter bridge circuit to control flow of current from the battery pack to the motor such that the motor produces a maximum power output of at least approximately 1750 watts at a torque of approximately 1.5 to 2 Newton-meters.

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.

A motor controller includes a rectifier module, an inverter circuit, an energy storage capacitor C1, a DC inductor L1, a microprocessor, and a lightning protection and surge protection circuit. The rectifier module includes an output end connected to the energy storage capacitor C1 to charge the energy storage capacitor C1; two ends of the energy storage capacitor C1 are connected to the inverter circuit to supply power to the energy storage capacitor C1. The DC inductor L1 is in series connection between a positive output end A of the rectifier module and a positive end B of the energy storage capacitor C1. The lightning protection and surge protection circuit is disposed between the rectifier module and the energy storage capacitor C1. The lightning protection and surge protection circuit includes a differential mode protection circuit and a primary common mode protection circuit.

A motor controller for an electric motor includes an enclosure and a processing device, memory device, and communication interface disposed within the enclosure. The processing device is configured to control the electric motor and collect operating information from the electric motor during operation of the electric motor. The memory device is communicatively coupled to the processing device. The memory device is configured to receive and store the operating information collected during operation of the electric motor. The communication interface is communicatively coupled to the processing device and the memory device, and is configured to enable access to the operating information stored on the memory device by a computing device disposed remotely from the electric motor.

A power tool is provided including a housing, a brushless motor disposed within the housing, a power switch circuit that supplies power from a power source to the brushless motor, and a controller configured to apply a drive signal to the power switch circuit to control the supply of power to the brushless motor. The controller is configured to receive at least one signal associated with a phase current of the motor, detect an angular position of the rotor based on the phase current of the motor within a variable speed range of zero to at least 15,000 rotations-per-minute (RPM), and control the drive signal based on the detected angular position of the rotor to electronically commutate the motor within a torque range of zero to at least 15 newton-meters (N.m.) and a power output of zero to at least 1500 watts.

The invention relates to a power system that includes an electrical machine, (e.g., a motor or generator). The electrical machine has a stator with a stator winding connected to a power converter. The power system includes an assembly to reduce, and optionally eliminate, common mode currents between the electrical machine and the power converter. The assembly includes a stator frame connected to ground potential and an electrical insulator (e.g., a plurality of stator mounts) located between the stator frame and the stator.