A half-bridge switching module is one of a plurality of half-bridge switching modules coupled to an input voltage to regulate energy provided to a load in response to a system controller. The half-bridge switching module includes a low-side switch. A low-side control is referenced to ground and is coupled to the low-side switch. A high-side switch is coupled to the low-side switch. A high-side control circuit is coupled to the high-side switch and is referenced to a floating node of the half-bridge switching module. A single fault terminal is coupled to a fault bus coupled to the system controller. The fault bus consists of a single wire. The single fault terminal is configured to provide multidirectional multi-fault group communication between the plurality of the half-bridge switching modules and the system controller through the fault bus.

A multiphase electric motor is disconnectable from a DC voltage source by way of a control unit. Phase windings with connection lines can each be alternately connected via a high-side and a low-side switching element to a respective pole of the DC voltage source, and the connection lines each have a device for disconnecting the phase windings from the DC voltage source upon a fault. The control unit may monitor the switching elements for short-circuit faults, switch off the switching elements when a fault occurs, determine whether the switching element causing the fault is a high-side or a low-side switching element, switch on at least a second of the high-side or correspondingly at least a second of the low-side switching elements in addition to the switching element causing the fault to brake the electric motor, switch off the switching elements after a braking period, and open the phase disconnection devices.

A controller for an electric motor system including a three phase bridge inverter having a plurality of high side switches and a plurality of low side switches, the controller comprising means arranged upon detection of a fault in one of the high side switches to place the remaining high side switches in a closed circuit configuration and the plurality of low side switches in an open circuit configuration and upon detection of a fault in one of the low side switches to place the remaining low side switches in a closed circuit configuration and the plurality of high side switches in an open circuit configuration to allow coil windings of an electric motor to be placed in a short circuit configuration.

A driving apparatus includes: an inverter unit generating a three-phase alternating-current voltage from a direct-current voltage in accordance with a drive signal based on a voltage command and outputting the three-phase alternating-current voltage to a permanent-magnet motor, the permanent-magnet motor including a permanent magnet; a current detection unit detecting a motor current flowing through the permanent-magnet motor; and a control unit generating the voltage command to control an operation of the inverter unit and estimating a temperature of the permanent magnet to perform a protection operation on the inverter unit on the basis of the motor current and an overcurrent protection threshold. The control unit sets the overcurrent protection threshold on the basis of a magnet temperature estimated value of the permanent magnet and any one of a control computation period of the control unit, an output voltage frequency of the inverter unit, and a carrier frequency based on the output voltage frequency of the inverter unit.

A system for controlling a plurality of motors includes: a variable frequency drive (VFD) configured to control at least one property of the motors, the VFD having a current interruption rating that is greater than a continuous current rating of all of the plurality of motors combined; a bus electrically connected to the VFD; and a plurality of protection modules, each protection module including: a motor overload device electrically connected to a particular one of the plurality of motors; and a switching relay in series with the motor overload device, the switching relay configured to connect the protection module to and disconnect the protection module from the bus. A state of the switching relay determines whether the protection module is electrically connected to the bus, the VFD is configured to control the state of the switching relay, and the switching relay has a current interruption rating that is less than the continuous current rating of the particular one of the plurality of motors.

An apparatus for protecting an electrical machine in the event of a fault, the electrical machine having six phase terminals includes a monitoring unit for detecting a fault of the electrical machine and a switchover unit for switching the electrical machine from a normal operating state into a short-circuit operating state if a fault of the electrical machine is detected. The switchover unit is designed to short-circuit the six phase terminals of the electrical machine asynchronously in accordance with a predefined pattern.

Systems and methods for extracting motor operational state parameters from an electric motor for improved motor control and motor fault or failure detection are discussed. An exemplary system includes an excitation circuit to apply a drive voltage to an electric motor, and a processor circuit to measure a resulting winding current, extract a current waveform by oversampling the winding current in an entire PWM frame at a sampling rate higher than the PWM frequency, and fit the current waveform in the PWM period to a parametric model. The processor circuit can determine a motor operational state parameter using one or more of the applied drive voltage or the parametric model of the winding current.

A switching control circuit configured to control a switching device. The switching control circuit includes a detection circuit configured to detect whether a current flowing through the switching device is in an overcurrent state, a first signal output circuit configured to output a first signal indicating whether a time period of the overcurrent state is longer than a first time period, and a driving circuit. The driving circuit turns on the switching device based on a first input signal. The driving circuit turns off the switching device through a first switch based on a second input signal when the time period of the overcurrent state is shorter than the first time period, and through a second switch, having a greater on-resistance than the first switch, based on the second input signal and the first signal when the time period of the overcurrent state is longer than the first time period.

An image forming apparatus is provided. The image forming apparatus includes a print engine to be used to perform an image forming job, a motor to start the print engine, a driving circuit to supply a power to the motor and to include a sensor to sense a size of current of the power supplied to the motor during an operation to perform the image forming job, and a processor to detect an occurrence of jam based on a size of current sensed by the sensor in a first time interval while the motor is driven and a size of current sensed by the sensor after a determined time from the first time interval.

Systems and methods for detecting a current measurement gain error in a current measurement system is disclosed. The method includes reading an output voltage signal, extracting a signature of a current measurement gain error from the output voltage signal, detecting an existence of the current measurement gain error based on the signature, and responsive to detecting the existence of the current measurement gain error, identifying a diagnostic voltage phase in which the current measurement gain error exists.