A motor drive circuit for driving an electric motor includes a plurality of driver circuits, each one of the plurality of driver circuit comprising a high side transistor coupled to a low side transistor in a half bridge arrangement, wherein each one of the high side transistors and each one of the low side transistors has a respective control node and respective first and second current passing nodes, wherein the second current passing node of each of the high side transistors is coupled to the first current passing node of a respective one of the low side transistors at a respective junction node, wherein each one of the plurality of driver circuits is operable to drive a respective current out of a respective junction node into a respective winding of the electric motor. The motor drive circuit further includes a capacitor coupled to the first current passing node of each one of the high side transistors, the capacitor operable to hold a capacitor voltage. The motor drive circuit further includes a power loss brake control circuit coupled to receive the capacitor voltage from the capacitor and operable to sense when a power supply voltage to the motor drive circuit is below a threshold voltage and, in a braking mode of operation, the high side transistors are off, and also in the braking mode of operation, when the power supply voltage is below the threshold voltage, the power loss brake control circuit is operable to generate at least one pulse signal having at least two state transitions and operable to communicate the at least one pulse signal to a respective at least one of the control nodes of a respective at least one of the low side transistors, resulting in on and off conditions of the at least one of the low side transistors, wherein the on condition of the at least one of the low side transistors results in the braking mode of operation during the on condition, and wherein the at least two state transitions results in a voltage boosting operation such that the capacitor voltage is a boosted voltage, the boosted voltage higher than a voltage that would be achieved without the at least two state transitions.

A motor drive circuit for driving an electric motor includes a plurality of driver circuits, each one of the plurality of driver circuit comprising a high side transistor coupled to a low side transistor in a half bridge arrangement, wherein each one of the high side transistors and each one of the low side transistors has a respective control node and respective first and second current passing nodes, wherein the second current passing node of each of the high side transistors is coupled to the first current passing node of a respective one of the low side transistors at a respective junction node, wherein each one of the plurality of driver circuits is operable to drive a respective current out of a respective junction node into a respective winding of the electric motor. The motor drive circuit further includes a capacitor coupled to the first current passing node of each one of the high side transistors, the capacitor operable to hold a capacitor voltage. The motor drive circuit further includes a power loss brake control circuit coupled to receive the capacitor voltage from the capacitor and operable to sense when a power supply voltage to the motor drive circuit is below a threshold voltage and, in a braking mode of operation, the high side transistors are off, and also in the braking mode of operation, when the power supply voltage is below the threshold voltage, the power loss brake control circuit is operable to generate at least one pulse signal having at least two state transitions and operable to communicate the at least one pulse signal to a respective at least one of the control nodes of a respective at least one of the low side transistors, resulting in on and off conditions of the at least one of the low side transistors, wherein the on condition of the at least one of the low side transistors results in the braking mode of operation during the on condition, and wherein the at least two state transitions results in a voltage boosting operation such that the capacitor voltage is a boosted voltage, the boosted voltage higher than a voltage that would be achieved without the at least two state transitions.

An electric motor connected to a switching device is braked from an active operating state by actuating a semiconductor switch arranged in parallel with an electromechanical switch to reduce a current intensity in the electromechanical switch, opening the electromechanical switch, blocking the semiconductor switch for an adjustable period, determining a resulting torque of the electric motor, and determining an actuation time for braking the electric motor based on the resulting torque and actuating the semiconductor switch at the actuation time. The resulting torque is opposite a present direction of rotation of the electric motor at the actuation time. The semiconductor switch is turned on for an adjustable actuation period. Also disclosed are a computer program product and a soft starter configured to implement the described method.

An electric motor connected to a switching device is braked from an active operating state by actuating a semiconductor switch arranged in parallel with an electromechanical switch to reduce a current intensity in the electromechanical switch, opening the electromechanical switch, blocking the semiconductor switch for an adjustable period, determining a resulting torque of the electric motor, and determining an actuation time for braking the electric motor based on the resulting torque and actuating the semiconductor switch at the actuation time. The resulting torque is opposite a present direction of rotation of the electric motor at the actuation time. The semiconductor switch is turned on for an adjustable actuation period. Also disclosed are a computer program product and a soft starter configured to implement the described method.

An inverter device includes a motor, a power supply that supplies the motor with electric current, an inverter that, during regenerative operation of the motor, performs switching between a first state in which regenerative current generated in the motor is returned to the motor again and a second state in which the regenerative current is supplied to the power supply, a first detector that detects a first condition electrically acting on the inverter, a second detector that detects a second condition electrically acting on the power supply, and a determiner that performs a first determination to perform switching between the first state and the second state, based on a detection result by the first detector or the second detector.

An inverter device includes a motor, a power supply that supplies the motor with electric current, an inverter that, during regenerative operation of the motor, performs switching between a first state in which regenerative current generated in the motor is returned to the motor again and a second state in which the regenerative current is supplied to the power supply, a first detector that detects a first condition electrically acting on the inverter, a second detector that detects a second condition electrically acting on the power supply, and a determiner that performs a first determination to perform switching between the first state and the second state, based on a detection result by the first detector or the second detector.

Methods and systems for controlling windmilling in an engine are described. An electric starter motor is coupled to the engine, a circuit element is coupled to the electric starter engine and to a DC signal source, and a control system coupled to the engine and to the circuit element. The control system is configured for: determining whether the engine is in a windmilling state; when the engine is in a windmilling state, commanding the circuit element to apply a DC signal to the electric starter motor; and modulating the DC signal applied to the electric starter motor to control a level of rotational motion of the engine.

A circuit for a smart safety system includes an electrical input connection to obtain power from a power source and an electrical output connection to regulate the power to an AC motor. The circuit also includes an adjustable DC power supply. One or more electronic switching devices regulate electricity output to the AC motor. The circuit has one more functional states including: a first state, activated via a first electrical signal, in which electricity is supplied to AC motor to allow normal operation of the AC motor, and a second state, activated via a second electrical signal, in which no electricity is supplied to the AC motor to prevent unintentional operation of the AC motor.

A circuit for a smart safety system includes an electrical input connection to obtain power from a power source and an electrical output connection to regulate the power to an AC motor. The circuit also includes an adjustable DC power supply. One or more electronic switching devices regulate electricity output to the AC motor. The circuit has one more functional states including: a first state, activated via a first electrical signal, in which electricity is supplied to AC motor to allow normal operation of the AC motor, and a second state, activated via a second electrical signal, in which no electricity is supplied to the AC motor to prevent unintentional operation of the AC motor.

A method for monitoring the performance of a mechanical brake for a linear electromagnetic motor, the linear motor having a linearly moveable output shaft, comprising monitoring travel of the output shaft over the duration of actuation of the mechanical brake and comparing said travel with a predetermined travel threshold.