A system for detecting a decrease in or loss of an input phase to a motor. A power rectifier rectifies and combines three input voltages to produce an output voltage to power the motor. A PFC circuit manages the power flowing to the motor. A sensing circuit located between the power rectifier and the PFC senses a voltage level of the power rectifier's output voltage. Alternatively, a sensing rectifier is connected before the power rectifier, and the sensing circuit senses the voltage level of the sensing rectifier's output voltage. A microprocessor compares the sensed voltage level to a threshold voltage level which is indicative of the decrease in or loss of one of the three input voltages, and if the former drops below the latter, then the microprocessor sends a signal to either shut off the motor or cause the PFC circuit to reduce the power flowing to the motor.

An electric motor control system, including an electric motor having a first winding set including first and second parallel windings, the first and second windings operable to each current based on the combined phase current, and a differential current sensor operably coupled to the first winding and the second winding. The differential current sensor measuring a differential current flowing through the first winding and the second winding and operable to transmit a signal indicative of the differential current based on the measuring. The system also includes a motor controller connected to the electric motor, the motor controller operable to direct the combined phase current through the phase lead, receive the differential current signal, determine if the differential current flowing through the winding set exceeds a selected threshold, and identify a health status of the motor winding set as degraded if the differential current exceeds the selected threshold.

An electric motor is electrically commutated with the aid of circuitry, in which the phase current experiences a zero crossing at certain time points per motor phase. Owing to the inductive load portion, the time of said zero crossing of a phase current occurs at different times to the time of the zero crossing that would arise with purely ohmic loads. Without a faulty load condition, the time of said zero crossing is within an expected value range (e.g., expected time window) which can be determined by the circuitry, the ambient conditions and by diverse motor parameters. During occurrence of the a high-side and/or low-side phase connection, it is determined whether and when the current through the switched-on high-side of low-side switch becomes greater or smaller than a predeterminable threshold wherein said time measurement can extend over one or more PWM cycles.

A steering apparatus, a steering method, and a steering control device. A steering motor includes a first winding and a second winding respectively receiving three-phase power. A first steering controller controls the power supplied to the first winding. A second steering controller controls the power supplied to the second winding. A detector detects whether or not a phase among three phases corresponding to each of the first and second windings is open; and a controller. If the phase among the three phases is detected to be open, the controller controls one steering controller corresponding to the open phase, among the first steering controller and the second steering controller, in accordance with an angular velocity of a steering wheel and the rotational speed of the steering motor, so that the steering motor generates additional torque.

The invention proposes a fault-tolerant field-oriented control method of five-phase interior permanent-magnet fault-tolerant linear motor (IPM-FTLM) with two nonadjacent short-circuit phase faults. Firstly, the extended Clark transformation matrix can be obtained according to the principle that magnetic motive force (MMF) keeps constant before and after the two-phase open-circuit faults, the constraint that the sum of healthy phase currents is zero and the adjacent two-phase current amplitude is equal. The back electric motive force (EMF) can be estimated by the transposed matrix. The nonlinear strong coupling system becomes the first-order inertia system when using the internal mode controller, the first-order inertia feed-forward voltage compensator and back-EMF observer, as the motor is with fault. Then, according to the principle that the sum of MMF of the healthy phase short-circuit compensation currents and two phases short-circuit fault currents is zero, the short-circuit compensation voltage can be obtained, and then these voltages add vector-controller output voltages, respectively. The invention not only restrains the thrust force fluctuation caused by two nonadjacent short-circuit phase faults, but also more importantly keeps the same dynamic and steady performance as the normal conditions, and also it has the constant switching frequency of voltage source inverter.

Provided is a control device 150 for an electric motor 140 which includes multiple energization systems each including an inverter and coils corresponding to different phases, and which generates a steering assist force in an electric power steering system. Control device 150 diagnoses whether any of inverters 1A and 1B fails, and, when either of the inverters is diagnosed as having failed, reduces the output ratio of the failing inverter to 0% while increasing the output ratio of the normally operating inverter to 100% so as to prevent a drop in the total output from all the inverters after the failure-positive diagnosis. If steering operation is performed after the failure-positive diagnosis, control device 150 performs overheat protection processing for gradually lowering the limit value for the total output from all the inverters in accordance with the sensed temperature of the normally operating inverter.

In a method for detecting a motor phase fault of a motor arrangement, the motor phases of which are connected to a drive circuit having a DC voltage intermediate circuit and an inverter. A motor phase voltage at at least one of the motor phases with respect to a reference potential is captured while the inverter is switched off; and a voltage profile of the captured motor phase voltage is used to determine whether there is a motor phase fault on one of the motor phases of the motor arrangement.

A drive circuit for driving an electronically commutated motor contains a DC voltage intermediate circuit, and an inverter which is connected to the latter and has a bridge circuit containing a plurality of circuit breakers, to which the motor phases of a motor configuration containing the motor can be connected. For detecting an insulation fault in the motor configuration, a positive or negative circuit breaker of the inverter is switched on, while all other circuit breakers of the inverter are switched off before all circuit breakers of the inverter are switched off. A motor phase voltage of a selected motor phase of the motor phases with respect to a reference potential is then captured, while all circuit breakers of the inverter remain switched off in order to determine whether there is an insulation fault on the motor phase on a basis of a voltage profile of the motor phase 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.

In a method and a corresponding device for detecting phase failures in a converter, current regulators of a positive phase sequence system and current regulators of a negative phase sequence system are provided for the current control of the converter, wherein the current regulators of the positive phase sequence system and the current regulators of the negative phase sequence system each have an integrator, resulting, in the case of a network fault, in coupling of the integrators. At least one measured or calculated value is checked by a monitoring unit for a course that is typical of the coupling of the integrators, wherein the monitoring unit generates a fault signal if such a typical course is detected.