A three-phase/two-phase conversion unit 43 generates a composite vector i.sub.αβ of three-phase AC currents based on AC currents iu, iv, and iw. An electrical angle calculation unit 44 outputs the electrical angle of the composite vector i.sub.αβ with reference to the U-phase AC current iu. A quadrant calculation unit 45 obtains which quadrant of the first to sixth quadrants partitioned in advance the acquired electrical angle corresponds to, confirms whether the composite vector i.sub.αβ passes through the set quadrant, and outputs quadrant information thereof. A failure detection unit 47 determines whether the composite vector i.sub.αβ has rotated from the first quadrant to the sixth quadrant, and when there is a quadrant that has not been passed, considers that it is a failure state, specifies a failure part of the switching element from the relationship between the electrical angle and the failure part, and outputs failure information to a PWM signal generation unit 42.

A motor control system and a vehicle. The motor control system includes: a vehicle control unit, configured to obtain vehicle state data and output an instruction for cutting off motor output torque when determining an unexpected power transmission failure according to the vehicle state data; and a motor controller unit, connected to the vehicle control unit, and configured to stop outputting motor control torque in response to the instruction for cutting off motor output torque.

Complicated system fault diagnosis method and system based on a multi-stage model are provided. The method includes: establishing an integer-order mathematical model, a 0.1-level fractional order mathematical model, and a 0.01-level fractional order mathematical model of a permanent magnet synchronous motor system; designing an integer-order status observer based on the integer-order mathematical model, designing a 0.1-level fractional order status observer based on the 0.1-level fractional order mathematical model, and designing a 0.01-level fractional order status observer based on the 0.01-level fractional mathematical model; corresponding residual values can be obtained by the observers and compared with corresponding threshold values to judge whether there is a fault. The system includes first through third modules. Observers with different accuracy degrees are set up and the permanent magnet synchronous motor system is diagnosed through the observers. The fault diagnosis method and system are mainly used in motor diagnosis.

Complicated system fault diagnosis method and system based on a multi-stage model are provided. The method includes: establishing an integer-order mathematical model, a 0.1-level fractional order mathematical model, and a 0.01-level fractional order mathematical model of a permanent magnet synchronous motor system; designing an integer-order status observer based on the integer-order mathematical model, designing a 0.1-level fractional order status observer based on the 0.1-level fractional order mathematical model, and designing a 0.01-level fractional order status observer based on the 0.01-level fractional mathematical model; corresponding residual values can be obtained by the observers and compared with corresponding threshold values to judge whether there is a fault. The system includes first through third modules. Observers with different accuracy degrees are set up and the permanent magnet synchronous motor system is diagnosed through the observers. The fault diagnosis method and system are mainly used in motor diagnosis.

According to some embodiments, a method for controlling a motor comprises generating a stall threshold based on a torque generating current parameter associated with the motor. A motor stall condition is identified based on a torque generating voltage parameter associated with the motor violating the stall threshold. Operation of the motor is adjusted responsive to identifying the motor stall condition.

A method of adaptively controlling a brushless DC motor includes steps of: controlling the brushless DC motor rotating at a first speed according to an operation curve, accumulating a running time of the brushless DC motor, estimating a remaining used time of a bearing of the brushless DC motor according to the accumulated running time, executing an alarm operation when the remaining used time is less than a predetermined time, and decreasing the speed of the brushless DC motor to run at a second speed to prolong the used time of the bearing.

A method of adaptively controlling a brushless DC motor includes steps of: controlling the brushless DC motor rotating at a first speed according to an operation curve, accumulating a running time of the brushless DC motor, estimating a remaining used time of a bearing of the brushless DC motor according to the accumulated running time, executing an alarm operation when the remaining used time is less than a predetermined time, and decreasing the speed of the brushless DC motor to run at a second speed to prolong the used time of the bearing.

A system and method for shaping the trajectory of a motion command to reduce the effects of a load on performance of a motor dynamically modifies the motion profile in real time to limit the reference signals in the motion profile to feasible commands. A load observer determines an estimated disturbance acceleration. The estimated disturbance acceleration includes the dynamics of the controlled load and is used to modify a maximum and a minimum limit for the acceleration reference. The acceleration limits are, in turn, used to determine velocity limits. The motion profile and modified acceleration and velocity limits are provided to a state filter which determines a new motion profile for use by the motor drive to control operation of a motor and to control the load connected to the motor.

A system and method for shaping the trajectory of a motion command to reduce the effects of a load on performance of a motor dynamically modifies the motion profile in real time to limit the reference signals in the motion profile to feasible commands. A load observer determines an estimated disturbance acceleration. The estimated disturbance acceleration includes the dynamics of the controlled load and is used to modify a maximum and a minimum limit for the acceleration reference. The acceleration limits are, in turn, used to determine velocity limits. The motion profile and modified acceleration and velocity limits are provided to a state filter which determines a new motion profile for use by the motor drive to control operation of a motor and to control the load connected to the motor.

A control unit determines a presence or absence of a short-circuit failure with respect to a target switch which is a phase-opening switch to be determined. At this time, after opening all the phase opening switches, the control unit drives an inverter to connect a power supply line provided with the target switch among the phase opening switches to ground. The control unit determines that the target switch has a short-circuit failure when a voltage of the power supply line in which the target switch is not provided is smaller than a predetermined voltage.