Abstract: A power control device for controlling an electrical load. The system includes decision logic to implement a local response responsive to events currently occurring in a power grid. The power control device includes a user interface allowing programming the response to the grid imbalance to adapt that response to the particular application in which the load operates.

Abstract: A gate driver circuit includes first through third transistors, a first voltage clamp, and control logic. The first transistor has a first control input and first and second current terminals. The first current terminal couples to a first voltage terminal. The first voltage clamp couples between the first voltage terminal and the first control input. The second transistor couples between the first control input and the second voltage terminal. The third transistor couples between the first control input and the second voltage terminal. The third transistor is smaller than the second transistor. The control logic is configured to turn on both the second and third transistors to thereby turn on the first transistor, and the first control logic configured to turn off the second transistor after the first transistor turns on while maintaining in an on-state the third transistor to maintain the first transistor in the on-state.

Abstract: A system includes a clamp network coupled between an input and an output and configured to clamp a voltage between the input and the output to a first clamp voltage based on the presence of a trigger signal and to a second clamp voltage based on the absence of the trigger signal. The second clamp voltage is greater than the first clamp voltage and the first clamp voltage is less than a breakdown voltage of the power transistor device. A detector circuit is coupled to the input and the output. A power transistor device may also be coupled between the input and the output. The detector circuit is configured to detect a pulse signal at the input or the output while the power transistor device is off and to generate the trigger signal for a time interval based on detecting the pulse signal.

Abstract: An amplification circuit includes a switch circuit, an amplifier, and a control circuit. The switch circuit has a first terminal coupled to a radio frequency signal input terminal or a system voltage terminal, a second terminal coupled to an input terminal of the amplifier, and a control terminal configured to receive a control signal. The amplifier amplifies a radio frequency signal. The control circuit generates the control signal according to a driving current generated by the amplifier. When the control circuit determines that the amplifier operates in a high power mode, the control circuit controls the control signal to adjust a conducting level between the first terminal and the second terminal of the switch circuit according to the intensity of the driving current.

Abstract: An apparatus and methods to operate the same to provide fast fault-detection on power semiconductor devices such as power transistors are disclosed. In some embodiment, a desaturation based fault-detection circuit for a power transistor is provided. The fault-detection circuit has an adaptable blanking time and a disconnect switch in the blanking mechanism that allow for quick enabling of fault-detection mechanisms to achieve fast fault detection times on power semiconductor devices.

Abstract: Provided is a vehicle controller that can suppress increase in startup time due to increase in the number of function portions related to communication. The invention includes a power supply unit 3 that is capable of supplying or shutting off operating power to a microcomputer 2 that communicates with other electronic control units through CAN channels (CAN1, CAN2), and communication controllers 4 and 6 that are respectively provided in the multiple CAN channels (CAN 1, CAN 2) used for communication of the microcomputer 2.

Abstract: Method, device and system for determining a line property in the form of an arc on a power transmission line, wherein at least one test signal is coupled into the power transmission and an interference signal at an interference point, which is formed by the arc, is generated along the power transmission line with the aid of the at least one test signal, which interference signal is acquired as at least one measuring signal, and the line property is determined from the at least one measuring signal, where the line property is determined by detecting at least one intermodulation product from the at least one test signal and the mains signal of the power transmission line in the at least one measuring signal.

Abstract: The invention relates to a grounding fault protection method for a high-voltage capacitor of a direct-current filter. The method comprises the following steps of acquiring a head end voltage u and an unbalanced current iT2 of a direct-current filter, and acquiring a discrete head end voltage and unbalanced current sequence; calculating a virtual capacitance Czd; determining a protection setting value Cset according to the bridge arm capacitance of the high-voltage capacitor, and when the virtual capacitance Czd is larger than the protection setting value Cset, protecting and judging to be an internal fault; otherwise, protecting and judging to be an external fault.

Abstract: One example includes a relay device that is comprised of a galvanic isolation barrier, a protection control and power extractor, and an electronic switch. The galvanic isolation barrier is coupled to an input of the relay device and receives a switch control signal and outputs another switch control signal. The protection control and power extractor is coupled to an output of the galvanic isolation barrier. The protection control and power extractor extracts power from a power supply coupled to the relay device. The protection control and power extractor is responsive to the other switch control signal and generates a protection signal in response to a determination of an operating parameter of the relay device. The protection control and power extractor further outputs an electronic switch device signal based on the generated protection signal.

Abstract: Wireless communication enabled circuit breakers are described. Methods associated with such wireless communication enabled circuit breakers are also described. The wireless communication enabled circuit breakers may controlled by a remote entity. The remote entity may wirelessly case the wireless communication enabled circuit breakers to trip.

Abstract: In an isolated DC-DC converter, in response to a switching transistor connected to the primary winding of a transformer turning off, a turn-on control circuit turns on a synchronous rectification transistor on the secondary side. A turn-off control circuit determines the turn-off time point of the synchronous rectification transistor by charging a capacitor with a current commensurate with the magnitude of an induced voltage appearing in the secondary wiring of the transformer during the on-period of the switching transistor and, after the synchronous rectification transistor turns on, discharging the capacitor with a current commensurate with the output voltage of the DC-DC converter.

Abstract: A power conversion system including a first converter configured to convert an input voltage into a plurality of discrete voltages. A second converter configured to convert the plurality of discrete voltages into a plurality of modulated voltages. Each modulated voltage of the plurality of modulated voltages comprises two voltage levels equal, respectively, to two of the discrete voltages of the plurality of discrete voltages. A selection unit configured to alternatively output each modulated voltage of the plurality of modulated voltages across a pair of output terminals.

Abstract: A power contact health assessor system includes a pair of terminals adapted to be connected to a set of switchable contact electrodes of a power contact and a contact separation detector configured to determine a time of separation of the set of switchable contact electrodes during deactivation of the power contact. The system includes a controller circuit operatively coupled to the pair of terminals and the contact separation detector. The controller circuit is configured to determine within a first observation window, a plurality of contact stick durations and an average contact stick duration. One or more additional observation windows with corresponding average contact stick durations are configured. A health assessment for the set of switchable contact electrodes may be based on a subsequent contact stick duration for a contact cycle after the first observation window and the corresponding average contact stick durations for the one or more additional observation windows.

Abstract: A method for protecting a circuit is provided, wherein the circuit comprises a plurality of switch devices connected in series. The method comprises detecting a failure risk indicator of each switch device; determining whether each switch device has a failure risk based on the corresponding failure risk indicator; and making each of the switch device(s) having the failure risk in a constant on-state to eliminate the failure risk and prevent a failure of the switch device optionally if a number of the switch device(s) which have or had the failure risk is less than or equal to a preset value.

Abstract: A system for emitting light (such as a luminaire) includes a first light emitting diode (LED) string and a first LED driver that is electrically connected in parallel to the first LED string. The system also may include a second (or more) LED string(s), each associated with an additional LED driver. One-way conductors and normally-open switches are used so that if one LED driver fails, the remaining LED driver(s) will deliver power to the failed driver's LED string so that the light remains operational, but with a reduced brightness.

Abstract: A power semiconductor circuit comprising a field effect transistor having a drain, a source and a gate as terminals, and further comprising a control device having a drive device and an undervoltage detection circuit. The drive device drives the field effect transistor and is electrically connected to the gate of the field effect transistor. The undervoltage detection circuit generates an undervoltage detection signal if a power semiconductor voltage present between the drain and the source of the field effect transistor falls below a specific voltage value. The drive device switches on the field effect transistor when a switch-on command for switching on the field effect transistor and the undervoltage detection signal are present. The invention provides a power semiconductor circuit with low energy loss.

Abstract: A system and method of determining a fault in two or more series switches of an electrical system. The electrical system includes, at least one AC power source, at least one sensor, at least two series switches, and a fault analysis module including a processor and a memory. The method includes applying, by the at least one AC power source, at least one time varying signal to the electrical system. The method further includes receiving, by the fault analysis module, at least one measurement, from the at least one sensor, of the at least one time varying signal, at least one node of the electrical system. The method further includes receiving, by the fault analysis module, at least one predetermined signal parameter and determining, by the fault analysis module, the presence of a fault, based on the at least one measurement and the at least one predetermined signal parameter.

Abstract: In one embodiment, a system includes a number of networking modules. Each module includes a respective voltage controller and a voltage-configuration circuit. The voltage-configuration circuit includes a number of transistors that are each coupled to a respective resistor. The system also includes one or more processors coupled to the voltage controllers including instructions executable by the processors. The processors being operable when executing the instructions to configure, for each module, an on-state or off-state of the transistors coupled to the respective resistor. The transistors coupled to the respective resistor correspond to a bit of a number of under-voltage thresholds. The processors are also operable to preset, during a module initialization, a relative ranking of under-voltage shutdown between the modules by setting the transistors. At least one of the number of networking modules has a different under-voltage threshold level relative to another one of the networking modules.

Abstract: A power electronic converter comprises controllable switches (104-109) and a control system (110) for operating the controllable switches. The control system is configured to control the controllable switches so as to produce at least one test voltage pulse. The power electronic converter comprises a voltage sensor (111) for detecting a reflected voltage that is caused by a reflection of the test voltage pulse in an electric system connected to the power electronic converter. The control system is configured to control the operation of the power electronic converter at least partly in accordance with information based on the detection of the reflected voltage. The information can be used for example for determining forbidden voltage pulse lengths which would cause reflection-based over-voltages and/or for detecting faults such as short circuits and earth faults.

Abstract: Provided is a portable rechargeable power supply device such that major accidents such as from overcharging due to a hazard prevention means being damaged by rain water, or the like can be prevented from occurring. This portable rechargeable power supply device comprises a lithium-ion battery (11), an assembled circuit board (20), and a case (40). Two terminals (31a, 31b), a hazard prevention circuit unit (26), and the like, are provided on the assembled circuit board (20). A terminal housing case portion (416) of the case (40) houses a first portion of the assembled circuit board (20), which is provided with the two terminals (31a, 31b). A main body housing case portion (417) of the case (40) houses the lithium-ion battery (11), and a second portion of the assembled circuit board (20), which is provided with the hazard prevention circuit unit (26), and the like.

Abstract: A converter includes a transformer including primary windings and secondary windings, switches connected to the primary windings, an output inductor connected to the secondary windings, and a controller connected to the switches. The controller turns the switches on and off based on dwell times calculated using space vector modulation with a reference current ref whose magnitude changes with time.

Abstract: The present disclosure relates to detection of faults in an electric power system. In one embodiment, an incremental quantities subsystem is configured to determine a forward torque, an operating torque, and a reverse torque based on the plurality of time-domain representations of electrical conditions. Each of the forward torque, the operating torque, and the reverse torque may be integrated over an interval. A fault detection subsystem may determine an occurrence of the fault based on a comparison of the operating torque to the forward torque and the reverse torque. Further, a direction of the fault may be determined based on the comparison of the forward torque, the operating torque, and the reverse torque. A fault may be declared based on the comparison and the direction. A protective action subsystem may implement a protective action based on the declaration of the fault.

Abstract: A field device with a microprocessor and a display and/or operating module, which can be disconnected from the field device, with the microprocessor showing an energy saving module, in which the display and/or operating module are switched off, with the waking circuit being provided, which generates a waking signal when the display and/or operating module are disconnected from the field device or connected thereto.

Abstract: Disclosed herein are various systems and methods for monitoring the health of a circuit breaker. In various embodiments, a system may receive a voltage measurement across a trip coil assembly associated with a circuit breaker. The system may further receive a current measurement through the trip coil assembly. A plurality of transition points may be identified based on at least one of the voltage measurement and the current measurement, the plurality of transition points corresponding to at least one of a mechanical characteristic and an electrical characteristic of the circuit breaker during a trip event. A predictive analysis may be performed based at least in part on the plurality of transition points. An indication of the predictive health may be displayed.

Abstract: Circuit protection devices, power distribution systems, and methods of monitoring circuit protection devices are described. In one example, a method of monitoring a circuit protection device in a zone selective interlocking (ZSI) system includes monitoring a variable associated with operation of the circuit protection device, determining, based at least in part on the monitored variable, when a likelihood of a malfunction of the circuit protection device exceeds a predetermined threshold, and preventing the circuit protection device from outputting a ZSI blocking signal when the likelihood of the malfunction of the circuit protection device exceeds the threshold.

Abstract: A multimedia delivery platform includes a platform manager configured to monitor status of platform resources including content acquisition resources and a managed element, visible to the platform manager, including an externally accessible contact closure. A state of the contact closure is specified by user input provided by a platform manager user. The platform includes a shaking device configured to shake a signal acquisition device such as a dish antenna. A power relay in the platform includes a control terminal coupled to the contact closure of the managed element and output terminals configured to deliver power to the shaking machine upon activation of the power relay.

Abstract: A circuit for sensing a difference in voltage on a pair of dual signal lines comprising a first signal line and a second signal line complementary to the first signal line, comprising: a pair of cross-coupled inverters arranged between the first and the second signal lines, each inverter having a pull-up transistor and a pull-down transistor, the sources of the pull-up transistors or of the pull-down transistors being respectively connected to a first and a second pull voltage signals, a decode transistor having source and drain terminals respectively coupled to one of the first and second signal lines and a gate controlled by a decoding control signal, whereby when the decode transistor is turned on by the decoding control signal, a short circuit is established between the first and the second signal lines through which current flows from one of the first and second pull voltage signals, thereby generating a disturb in between the first and the second pull voltage signals.

Abstract: A multiport AC link converter includes a resonant AC link, an input port, an output port, and a plurality of switches. A first subset of the switches is between the input port the resonant link and a second subset of the switches is between the resonant link and the output port. The switch sequencing for the input port is selected and executed independently of the switch sequencing for the output port the switch sequencings for the output port is selected and executed independently of that for the input port.

Abstract: A circuit arrangement includes a load current controller (10a) and a monitoring device (11a, 11b). The load current controller (10a) has its input side connected to a first reference signal connection (A6) and a load reference connection (A2), the latter being able to be coupled to an output of the current source (SQn) and being designed to provide a control signal (IB) at an output which is coupled to a control connection (A1) for controlling the current source (SQn). The control signal (IB) is determined on the basis of a comparison of a load current (IL) with a first reference signal (IL-REF, IREF, VREF). The monitoring device (11a, 11b) has its input side coupled to the output of the load current controller (10a) and to one of the inputs of the load current controller (10a). The monitoring device (11a, 11b) is designed to provide a feedback signal (RS) at an output coupled to the feedback connection (A3) on the basis of a comparison of the control signal (IB) with the load current (IL).

Abstract: An electronic device includes a port for connecting the electronic device to other electronic devices and a moisture detector configured to detect an electrically conductive liquid in the first port. The moisture detector is configured to maintain a voltage on a first electrical contact of the port and to detect a short circuit between the first electrical contact and a second electrical contact of the port. The moisture detector determines that the electronic device has been exposed to an electrically conductive liquid if the monitor module detects the short circuit. The moisture detector may also put the electronic device into safe mode if it is exposed to an electrically conductive liquid.

Abstract: A protection device includes a pair of electrodes and an output unit. In the pair of electrodes, one electrode, connected to a connection line that connects a load and a power supply that supplies voltage to the load, performs discharge toward the other electrode in response to application, to one electrode, of an abnormal voltage greater than or equal to a pre-set voltage exceeding a steady-state voltage output by the power supply in a steady state. The output unit detects discharge current that flows in the other electrode and outputs the detected discharge current as a control signal.

Abstract: A method for operating a brushless electric motor, the windings being energized by an inverter with the aid of six switches. A detection unit for detecting defective switches, a unit for measuring voltage at the outputs of the inverter, and a microcontroller for controlling the switch and for generating a pulse width modulated voltage supply for the windings are provided. A short-circuited switch causes a torque in the electric motor opposite the actuating direction of the electric motor. The method proposes that after detecting a short-circuited switch, the windings (U. V. W) are energized to generate a motor torque that is, on the whole, positive. An actuating period of the electric motor is divided into a plurality of sectors, wherein, in accordance with the defective switch, individual sectors are deactivated for the actuation of the windings (U, V, W), while other sectors are used to actuate the windings (V, W).

Abstract: When a continuous short circuit occurs between both terminals of a battery pack, fault, destruction and rupture of the battery can occur. Further, when a momentary short circuit occurs, a user may continue to use, without knowing thermal and electrical damage to the batteries, and reliability for the batteries is impaired, To overcome the problem, in a battery pack configured by connecting a plurality of storage batteries in series, at least one first storage battery is included which has a low capacity compared to second storage batteries during high-rate discharge, and the first storage battery undergoes polarity inversion during external short circuit, thereby preventing the other batteries from becoming damaged. There are also included a detector that detects voltage of the first storage battery, and a fault signal generator that generates an output fault signal when a voltage detected by the detector inverses.

Abstract: A solid state primary power switching network for modular equipment centers (MECs) distributing primary power throughout a vehicle. The solid state primary power switching network includes multiple primary power switch network devices (PPSNDs) of a MEC for controlling and distributing primary power to other MECs spatially distribute throughout a vehicle. In one or more configurations, the PPSNDs have a universal structure in that each includes a common power input source and a plurality of common power outputs. In one or more configurations, primary power sources to the vehicle are switched without a perceivably visible break in power.

Abstract: The relay-welding detection circuit detects welding of relays (RYP, RYN) provided on a charging path from an external power supply (PW) to a first battery (14), and is provided with: a second battery (15) that can supply a welding-detection power supply independently of the external power supply (PW); a transistor switch (17) that is a circuit in which there is substantially zero current flowing in from the external power supply (PW) side of the relays, and that controls whether or not to supply the welding-detection power supply to the second battery (15) on the basis of the voltage at the external power supply (PW) side of the relays; and a control unit (18) that is electrically insulated from the transistor switch (17), and that to detects welding of the relays (RYP, RYN) on the basis of whether or not the transistor switch (17) has supplied the welding-detection power supply.

Abstract: A distributed energy resources control apparatus for controlling power from a distributed energy resource in a system section separable from a power system includes a detecting unit, a receiving unit, and a control unit. The detecting unit detects a fault of the power system. The receiving unit receives a signal indicating authorization for the distributed energy resource to perform independent operation as linking with the system section, when the system section is separated from the power system. The control unit controls a power converter converting power from the distributed energy resource and outputting to the system section, based on measurement results of a voltage and a frequency of the system section, when the fault is detected and the signal is received.

Abstract: An alarm system for alarming whenever there is a power leakage from an electronic device, includes a voltage decreasing circuit, a switch circuit and an alarm circuit. The voltage decreasing circuit receives a first voltage from a live wire output terminal and outputs a second voltage. The switch circuit outputs a control signal when the power leakage is detected. The switch circuit is electrically connected to a connection port. The connection port is electrically connected to the live wire output terminal and a neutral wire output terminal. The alarm circuit receives the control signal and alarms. If there is power leakage from the electronic device, the first voltage from the live wire input terminal flows into the ground wire input terminal via the electronic device; the switch circuit turns on and the alarm circuit is closed to alarm.

Abstract: A power distribution system comprises a power supply, a plurality of loads connected to one of the power supply and ground and a plurality of pulse generators, each pulse generator connected to each of the plurality of loads, configured to generate pulses to connect the plurality of loads to the other one of the power supply and ground at predetermined frequencies.

Abstract: Systems and methods for monitoring excitation of a generator based on a faulty status of a generator breaker are provided. According to one embodiment, a system may include a controller and a processor communicatively coupled to the controller. The processor may be configured to receive, from a contact associated with a generator breaker, a reported status of the generator breaker, receive operational data associated with one or more parameters of a generator associated with the generator breaker, and correlate the reported status of the generator breaker and the operational data. Based on the correlation, the processor may establish an actual status of the generator breaker, and, based on the actual status, selectively modify a mode of excitation of the generator.

Abstract: A control circuit, comprising a protection detection circuit, a protection synchronous output circuit, a protection synchronous input circuit and a protection circuit, is provided. The protection detection circuit is adapted to generate an error notice signal when detecting an error condition. The protection synchronous output circuit is coupled to the protection detection circuit for enabling a level of a protection synchronous pin to be a protection level when receiving the error notice signal. The protection synchronous input circuit is coupled to the protection synchronous pin for generating a synchronous protection signal when the level of the protection synchronous pin has been at the protection level for a predetermined time period. The protection circuit generates a protection signal to make the control circuit enter a protection mode when receiving one of the error notice signal and the synchronous protection signal.

Abstract: A central processing unit (CPU) power controller includes a power supply unit, a CPU power controller, a detecting circuit, a temperature compensation circuit, an inductor, a thermistor, first and second switches, and first and second capacitors. The detecting circuit outputs a detected voltage of an inductor to the CPU power controller. The temperature compensation circuit outputs a detected voltage of the thermistor to the CPU power controller, to compensate for changes in the voltage of the inductor. If the detected voltage is greater than the rated voltage, the first switch is opened and the second switch is closed. The inductor discharges. If the detected voltage of the inductor is less than the rated voltage, the first switch is closed and the second switch is opened, the power supply unit charges the inductor to increase the voltage of the CPU.

Abstract: Variable frequency motor drives and control techniques are presented in which filter capacitor faults are detected by measuring filter neutral node currents and/or voltages and detecting changes in a frequency component of the measured neutral condition and/or based on input current unbalance.

Abstract: A motor controller with a reverse-bias preventing mechanism includes a pre-charging unit, a protection unit, a conversion unit and a control unit. The pre-charging unit receives a power signal through a first electric-conduction path, and converts the power signal into a pre-charging signal according to a control signal. The protection unit receives the power signal through a second electric-conduction path, and determines whether to output the power signal, according to the polarity of the power signal. The conversion unit, coupled to the protection unit, receives the power signal outputted by the protection unit, and converts the power signal into a work voltage. The control unit, coupled to the conversion unit and the pre-charging unit, receives the work voltage to generate the control signal. The current of the power signal flowing through second electric-conduction path is smaller than the current flowing through first electric-conduction path.

Abstract: In an integrated circuit device having an internal circuitry that requires voltage protection (e.g. negative voltage protection), the voltage protection is provided by a FET. In some embodiments, the source and drain of the FET are connected in series with the internal circuitry and an I/O node through which the voltage can be received (e.g. the source connected to the internal circuitry and the drain connected to the I/O node). In some embodiments, the FET is drain-extended (e.g. a drain-extended PFET).

Abstract: A first power line configured to receive a first voltage, a second power line configured to receive a second voltage which is lower than the first voltage, a first clamping unit configured to be connected to the first power line, a second clamping unit configured to be connected between the first clamping unit and the second power line, and a discharging unit configured to, when an abnormal voltage introduced through the first power line or the second power line is applied, discharge the abnormal voltage by coupling with the first clamping unit or the second clamping unit are included.

Abstract: A high-side output transistor and a low-side output transistor of an output circuit control voltages of conductors, which connect a power supply terminal and ground, and outputs a voltage signal to an output terminal through an output conductor. A voltage output circuit detects a voltage applied to the high-side output transistor based on a potential difference of a first resistor provided closer to the output terminal side. A comparator circuit outputs a signal to turn off a first switch and a second switch provided in the conductors, when the output voltage of the voltage output circuit exceeds a reference voltage Vr.

Abstract: Multiple-contact switches are disclosed. An example multiple-contact switch disclosed herein includes a double throw switch having a common terminal, a first throw terminal, and a second throw terminal, the common terminal being coupled to a reference; a first throw circuit coupled to the first throw terminal, the first throw circuit to output an open signal to a process control device when the common terminal is substantially in contact with one of the first throw terminal or the second throw terminal; and a second throw circuit coupled to the second throw terminal, the second throw circuit to cause the first throw circuit to output a close signal to the process control device when the common terminal is substantially in contact with the other one of the first throw terminal or the second throw contact terminal, wherein at least one of the open signal or the close signal corresponds to the reference.

Abstract: A load driving device according to an exemplary aspect of the present invention includes: an output transistor coupled between a first power supply line and an output terminal, the output terminal being configured to be coupled with a load; a protection transistor that is provided between a gate of the output transistor and a second power supply line, and brings the output transistor into a conduction state when a polarity of a power supply coupled between the first power supply line and the second power supply line is reversed; and a back gate control circuit that controls the second power supply line and a back gate of the protection transistor to be brought into a conduction state in a standby mode when the polarity of the power supply is normal.

Abstract: A battery management system for a vehicle having an electrically powered motor that is powered by a plurality of battery cells includes an electrical system for providing voltage and current from the battery cells to an electrical motor. A control is operable to at least one of (a) cause fuses of the electrical system to be the weakest link in the electrical system only during a failure event, (b) disconnect the battery cells from the battery management system only during a failure event, (c) separate the driving of balancing resistors into first and second stages, with the first stage comprising cell balancing control and the second stage comprising cell balancing with reverse voltage protection and (d) provide single stage reverse voltage protection to limit or effectively eliminate an electrical conduction path through a low impedance balancing circuit.

Abstract: When a short-circuited FET is identified as one of low-side FETs, maximum phase voltages of three phases are detected when a steering operation is performed by a driver, and the detected maximum phase voltages of the three phases are compared with one another to identify a short-circuit phase. On the other hand, when a short-circuited FET is identified as one of high-side FETs, minimum phase voltages of the three phases are detected when a steering operation is performed by the driver, and the detected minimum phase voltages of the three phases are compared with one another to identify a short-circuit phase.