A motor drive control device driving a motor having a first system coil and a second system coil, the motor drive control device comprising: a first drive circuit controlling energization of the first system coil; a second drive circuit controlling energization of the second system coil; and a signal output circuit detecting a first voltage that is a voltage at a middle point of the first system coil and a second voltage that is a voltage at a middle point of the second system coil, and outputting an output signal concerning whether or not any one of the first system coil and the second system coil is in an open state, based on a detection result of the first voltage and a detection result of the second voltage.

A system and a method of isolating a fault in an electric motor system having a motor drive electronics (MDE) component that is configured to drive an electric motor with a plurality of phases, the MDE executing a method of isolating the fault that includes applying an excitation to a first phase and a second phase of the electric motor in a first direction and sensing a phase current value for each phase phases of the electric motor. The method also includes providing an excitation, for the first and second phase in an opposite direction of the first direction and measuring a phase current value for each phase. The applying, sensing, providing and measuring is repeated for every possible combination of phases of the electric motor. Finally, the method includes isolating the fault within the electric motor system based on the sensed and measured current values.

A controller and a plurality of driver circuits may be configured to operate selectively either in a normal mode or in a diagnostic mode. In the normal mode, the controller is configured to transmit a drive signal to each driver circuit via a corresponding drive signal line. Each driver circuit is configured to drive corresponding switching element(s) in response to the drive signal and is further configured to output a failure signal when the driver circuit detects a failure related to the corresponding switching element(s). In the diagnostic mode, the controller is configured to sequentially transmit a request signal to the driver circuits via their corresponding drive signal lines, and each driver circuit is configured to output the failure signal in response to the request signal in a case of having detected the failure during operation in the normal mode.

A method of classifying a stator winding fault in a brushless synchronous generator includes measuring an electrical parameter of the stator winding and classifying the fault by calculating positive or negative sequence harmonics of the parameter and comparing one or more harmonic component to a threshold.

A short detection apparatus configured to detect a layer short in a motor in which a plurality of sets of multi-phase windings are independently disposed in a stator includes an acquisition unit configured to acquire electricity information corresponding to windings of individual phases in the sets of the multi-phase windings; and a determination unit configured to determine, based on the electricity information which the acquisition unit acquires with respect to windings of a mutually identical phase in the sets of the multi-phase windings, whether a layer short occurs in any one of the windings of the mutually identical phase.

A method for determining an interrupted motor phase of an electric motor having at least three windings by means of a control unit is disclosed, wherein voltages induced in the windings are determined on outer conductors of the electric motor by means of at least one measuring unit, wherein the measuring unit is connected to at least one outer conductor of the electric motor via at least one resistor, the induced voltages of the outer conductors of the electric motor are compared with one another, and an interrupted motor phase is registered if the induced voltage differs or if a frequency of the induced voltage differs. A control unit, a computer program and a machine-readable storage medium are also disclosed.

A motor drive system can detect a misconnection. A motor drive system for driving a motor including a plurality of stator windings includes: an inverter that converts a DC voltage supplied from a DC voltage source into an AC voltage and applies the AC voltage to the motor; a connection switching device that is disposed between the inverter and the motor and can switch a connection state of the stator windings; and a controller that performs abnormality determination on a connection state of the connection switching device on the basis of a current value of a current flowing in each of the stator windings.

A motor control circuit for an electric motor of an electric power assisted steering system comprises a switching circuit comprising a plurality of electrical switches, a current demand signal generator which converts the torque demand signal into a current demands signal; and a fault mode motor current controller that is responsive to an error signal that represents the difference between the current demand signal and the actual current flowing in the motor and is operable in the event of a fault where one phase is open-circuit to drive the remaining two phases as a single combined phase by generating a single voltage demand signal that is representative of the voltage to be applied across the combined phases, the voltage signal being in turn fed into a drive circuit for the switches that generates pulse width modulated switching signals for the switching circuit required to apply the voltage across the combined phases.

A control system for an electric motor comprises a current controller which produces a set of voltage demands for the motor, a current sensing means arranged to produce a current sensing output indicative of electric current in the motor, and a current signal processing means arranged to process the current sensing output signal to produce a modified current signal in which at least one harmonic component present in the current sensing output signal due to inaccuracies in the current measurement is removed or substantially reduced. The modified current signal is combined with a demanded motor current to provide the input to the current controller.

A power conversion apparatus with an arm fuse melting detector for detecting an arm fuse melting from a ripple current without using a micro switch. The power conversion apparatus includes an inverter for driving a motor, an arm fuse provided in each of U-phase, V-phase, and W-phase arms of the inverter, and a first arm fuse melting detector to detect the arm fuse melting. The first arm fuse melting detector includes a DQ conversion circuit that converts the inverter output current into the D-axis/Q-axis current, an absolute value calculation circuit for calculating the absolute value from the output of the DQ conversion circuit, a ripple current calculator for calculating a ripple current from the difference between the maximum value and the minimum value of the absolute value for each cycle period T of the fundamental wave of the inverter output.