A motor drive device includes a plurality of control systems that individually supply drive currents to a plurality of coil groups included in a motor. The motor drive device independently sets the current command values for the respective control systems. Based on the set current command values, drive instructions are supplied to drive circuits of inverters with respect to the respective control systems, thereby supplying drive currents from the inverters to the coil groups. The motor drive device detects a failure in any of the inverters and the coil groups with respect to each control system, and stops only the failed control system or causes only the failed control system to fall back. The motor drive device further includes a main computing device, and an auxiliary computing device. Consequently, if the auxiliary computing device is normal even in case the main computing device fails, driving of the motor can be continued using one or some of the control systems.

In a motor driving apparatus including an inverter connectable to n motors (n being an integer not less than 2) each including a rotor having a permanent magnet, braking operation is performed on i (i being an integer from 1 to n−1) of the n motors, and then braking operation is performed on j (j being an integer from 1 to n−i) of the n motors other than the i motors. It is possible to reduce the risks of failure of the inverter and demagnetization of the motors due to overcurrent by reducing current flowing through the inverter and the motors when the braking operation is performed.

In a motor control device that can perform more appropriate motor control, a switching arm has a first upper FET, a second upper FET, and a lower FET connected in series to one another. A source electrode of the second upper FET and a drain electrode of the lower FET are connected to each other via an intermediate line. The intermediate line is connected to a U-phase motor coil of a motor via a power line. The first upper FET, the second upper FET, and the lower FET are each provided with a parasitic diode that prevents current from flowing from a battery side to a ground side. A phase opening relay FET is provided on the U-phase power line. A parasitic diode of the phase opening relay FET is provided such that a current is not applied from the U-phase motor coil to the U-phase switching arm.

A system, a switch assembly and an associated method. The system includes a number of switch assemblies, each including a switch module, isolation circuits, a detection unit, and a drive unit. The switch module includes power switch devices connected in parallel. The switch modules are connected in series. The isolation circuits each are connected in series to a gate terminal of at least one corresponding power switch device of the power switch devices. Each isolation circuit includes a capacitor or a controllable switch. The detection unit detects faults in at least one of the power switch devices. The drive unit is coupled to the switch module via the isolation circuits for driving the power switch devices of the corresponding switch module, and when the fault is detected, the drive unit is for turning on the power switch devices parallel connected to the at least one of faulty power switch devices.

A power system for a marine ship includes a plurality of protection zones, wherein at least two protection zones are coupled to each other via at least one bus-tie converter. Each of the protection zones includes a plurality of direct current (DC) buses and a plurality of power converters. The bus-tie converter includes at least two converter legs coupled by at least one inductor. Each converter leg includes a first branch connected with a snubber circuit. The first branch includes two outer switching devices and at least one inner switching device connected between the two outer switching devices. The first branch also includes a damping resistor coupled between the two outer switching devices to dissipate a fault current. The snubber circuit includes a combination of a diode, a resistor and a capacitor. A controller controls the operation of the plurality of power converters and the at least one bus-tie converter.

A chopper device includes: a series circuit connecting at one end to a positive pole of a DC power source and having a breaker and a reactor; a series circuit connected between another end of the stated series circuit and a negative pole of the DC power source and having switches; a series circuit connected in parallel to the switch and having a diode and a capacitor; and a series circuit connected in parallel to the switch and having a diode and a capacitor. The chopper device outputs a DC voltage at three potentials from both ends and a midpoint of a series circuit having the capacitors by turning the switches ON/OFF. The chopper device further includes other switches connected in parallel to the switches. When a short-circuit fault is presumed to have occurred in the switch, the other switch is turned ON before interruption is performed by the breaker.

A compact motor control system for selectively controlling power from a power source to a load includes a motor switching assembly having a solid state contactor with a plurality of solid state switches. The motor switching assembly also includes at least one direct current (DC) link coupled to the solid state contactor and redundant first and second inverters coupled to the at least one DC link. The motor switching assembly further includes a first relay coupled between the solid state contactor and an input of the inverter and a second relay coupled between the solid state contactor and an input of the second inverter. In addition, the motor control system includes a control system programmed to control the motor switching assembly to selectively supply power to the load from the power source.

The present invention relates to switching element protection of a BLDC motor, such as used with a power tool. The present invention checks each switching element of a power stage individually for a short circuit when a trigger of the tool is actuated. Each switching element is turned ON for a period of time (such as 1-5 microseconds, for example), current flowing through the half-bridge or the full power stage is measured, and that switching element is turned OFF. When the current is greater than or equal to a threshold (such as 5 A, for example), the controller stops and indicates a fault condition. By testing each switching element in order, the controller is able to determine whether the shorted switching element is the opposite one in the half-bridge being tested.

A vehicle driving device includes an inverter which drives a motor. The inverter includes: a three-phase bridge circuit including a plurality of switching elements; a three-phase short circuit which short-circuits three phases of the motor via the three-phase bridge circuit; and a control circuit. The control circuit includes: a microprocessor which drives the three-phase bridge circuit; a malfunction notification circuit which outputs a malfunction notification signal when the microprocessor is malfunctioning; and a latch circuit which holds the malfunction notification signal outputted from the malfunction notification circuit. The control circuit outputs a three-phase short-circuit drive signal which drives the three-phase short circuit, based on the malfunction notification signal held by the latch circuit.

A motor drive circuit for use in driving a motor having two or more phases comprising a motor bridge having, for each phase of the motor, a bridge arm comprising an upper switch and a lower switch that in normal operation may be opened and closed to modulate the voltage applied to the respective phases in response to drive signals from a motor control circuit, at least one solid state phase isolation relay that is provided in series in an electrical path connecting a respective phase of the motor to a respective bridge arm, the relay being closed in normal operation so that current can flow in the phase and is held open in a fault mode of operation to prevent the flow of current in the phase. The circuit also includes monitoring means for monitoring the current waveform in the phase to provide, at least in a fault mode of operation, an output indicative of when it is safe to open the SSPIR without causing damage due to the SSPIR due to an avalanche mode, and a control circuit that during normal operation applies a voltage to each device that is sufficient to hold the SSPIR closed and which, in the fault mode of operation, responds to the output of the monitoring means to reduce the voltage applied to each SSPIR to a level that causes the SSPIR to open at the safe time.