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.

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 protection device provided between a synchronous motor having a plurality of windings and a motor driving device for driving the synchronous motor includes: a switching unit for making and breaking the connection between the motor driving device and the synchronous motor; a dynamic brake circuit including resistors and switches, to short-circuit the plurality of windings between the switching unit and the synchronous motor via the resistors; and a control device for controlling the switching unit and the dynamic brake circuit. The control device controls the switches in the dynamic brake circuit to short-circuit the plurality of windings, and then controls the switching unit to cut off the connection between the motor driving device and the synchronous motor.

An electromechanical motor vehicle power steering system having a multiphase, permanently excited electric motor via a controller and supply lines from an onboard power supply of a motor vehicle.

A power-conversion device and a ground-fault-location-diagnosis method for determining ground-fault locations on a motor and a cable are disclosed. The power-conversion device includes a ground-fault-current-measurement unit, an interphase short-circuit current-measurement unit, and a ground-fault-location-determination unit. The ground-fault-current-measurement unit turns on all switches of either upper arms or lower arms of three half-bridge circuits, and measures output current values of a plurality of phases generated during the ON period. The interphase short-circuit-current-measurement unit turns on a switch of an upper arm of one phase of the three half-bridge circuits and a switch of a lower arm of a phase different from the one phase, and measures output current values of a plurality of phases generated during a period of time both switches are ON. The ground-fault-location-determination unit determines a ground-fault location based on output-current values measured by the ground-fault-current-measurement unit and the output-current values measured by the interphase short-circuit current-measurement unit.

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.

A current limit protecting system and method of a motor pre-driver are provided. A current limiting circuit detects a current of a resistor that is connected to a motor, and then compares the current of the resistor with a current threshold to output a current comparing signal. When a controller circuit determines that the current of the resistor is larger than the current threshold according to the current comparing signal, and a working period of a first signal of a first node or a working period of a second signal of a second node of the motor reaches a preset value, a first high-side switch and a second high-side switch are turned off, and a first low-side switch and a second low-side switch are alternately turned on. As a result, a temperature of the motor generally reduces.

An overvoltage protection circuit can be applied to a motor controller. The motor controller is used for driving a motor, where the motor has a motor coil. The motor coil has a first terminal and a second terminal. The motor controller comprises the overvoltage protection circuit and a switch circuit. The switch circuit is an H-bridge circuit and includes two upper-side switches and two lower-side switches. The overvoltage protection circuit comprises a pre-driver, a phase detecting unit, a control unit, and an overvoltage detecting circuit. When an overvoltage occurs at the first terminal or the second terminal, the overvoltage protection circuit is configured to suppress a voltage spike by turning on two upper-side switches or two lower-side switches.

An electromechanical motor vehicle power steering system having a multiphase, permanently excited electric motor via a controller and supply lines from an onboard power supply of a motor vehicle.

A power converter includes a first inverter, a second inverter, and a switching circuit including first and second switching elements. In a state in which, in the first inverter, potentials at a first node in a high side and a second node in a low side are equal to each other, and potentials at first ends of two-phase windings of n-phase windings with n being an integer of 2 or more are equal to each other, two-phase windings are energized using two legs connected to second ends of the two-phase windings of n legs of the second inverter while performing switching operations on the first and second switching elements of the switching circuit at a predetermined duty ratio.