A power management system comprises an AC-power-source controller configured to control power supply between the AC power source and a common DC bus, the AC-power-source controller further configured to limit AC power supplied from the AC power source to the common DC bus to a first AC-power-source power limit; a power inverter configured to invert the DC power on the common DC bus into AC output power for driving the electric motor; a DC power source configured to supply DC power to the common DC bus; and a DC-power-source controller configured to control power supply between the DC power source and the common DC bus, the DC-power-source controller further configured to start supplying DC power from the DC power source to the common DC bus in response to a detection of a voltage drop on the common DC bus from a AC-power-source reference voltage to a DC-power-source reference voltage.

A motor control apparatus includes control circuitry and rotation direction adjusting circuitry. The control circuitry is configured to output, in accordance with a phase sequence with respect to a motor, a drive command signal which is generated based on a motor rotation signal output from a motor rotation detector to control the motor. The rotation direction adjusting circuitry is configured to match the phase sequence with rotation direction information included in the motor rotation signal if a first trouble signal showing excessive motor current or excessive motor speed is input via an operation unit.

A three-phase regenerative drive configured for operation from a single phase alternating current (AC) power source, the three-phase regenerative drive including a three-phase converter having inputs for connection to a single-phase AC source, the three-phase converter having three phase legs, a three-phase inverter for connection to a motor, the three phase inverter configured to provide three phase command signals to the motor, and a DC bus connected between the three-phase converter and the three-phase inverter. A first phase leg of the three-phase converter and a second phase leg of the three-phase converter are employed to direct current from the single-phase AC source to the DC Bus and a third phase leg of the three phase legs of the three-phase converter returns current to a return of the AC source.

A conveyance system includes a machine having a motor; a source of AC power; a drive system coupled to the source of AC power, the drive system to provide multi-phase drive signals to the motor, the drive system including: a first drive having a first converter and a first inverter, the first convertor including a first positive DC bus and a first negative DC bus; a second drive having a second converter and a second inverter, the second convertor including a second positive DC bus and a second negative DC bus; wherein the first positive DC bus and the second DC positive bus are electrically connected and the first negative DC bus and the second negative DC bus are electrically connected.

A semiconductor device according to an embodiment includes: a silicon carbide layer; a silicon oxide layer; and a region disposed between the silicon carbide layer and the silicon oxide layer and having a nitrogen concentration equal to or more than 1 × 10.sup.21 cm.sup.-3. A nitrogen concentration distribution in the silicon carbide layer, the silicon oxide layer, and the region have a peak in the region, a nitrogen concentration at a first position 1 nm away from the peak to the side of the silicon oxide layer is equal to or less than 1 × 10.sup.18 cm.sup.-3 and a carbon concentration at the first position is equal to or less than 1 × 10.sup.18 cm.sup.-3, and a nitrogen concentration at a second position 1 nm away from the peak to the side of the silicon carbide layer is equal to or less than 1 × 10.sup.18 cm-.sup.3.

A semiconductor device of an embodiment includes: a first trench in a silicon carbide layer and extending in a first direction; a second trench and a third trench located in a second direction orthogonal to the first direction with respect to the first trench and adjacent to each other in the first direction, n type first silicon carbide region, p type second silicon carbide region on the first silicon carbide region, n type third silicon carbide region on the second silicon carbide region, p type fourth silicon carbide region between the first silicon carbide region and the second trench, and p type fifth silicon carbide region located between the first silicon carbide region and the third trench; a gate electrode in the first trench; a first electrode; and a second electrode. A part of the first silicon carbide region is located between the second trench and the third trench.

The invention relates to a safety arrangement of an elevator, which includes sensors configured to indicate functions that are critical to the safety of the elevator, and also a safety circuit, with which the data formed by the sensors indicating the safety of the elevator is read. The safety arrangement includes a drive device including a control circuit of a motor bridge, an input circuit for a safety signal that can be disconnected/connected from outside the drive device, and also drive prevention logic, to prevent the passage of control pulses to the control poles of high-side and/or low-side switches of the motor bridge when the safety signal is disconnected. The safety circuit brings the elevator into a state preventing a run by disconnecting the safety signal and removes the state preventing a run by connecting the safety signal.

A passenger transport system includes a three-phase drive motor, a control device and an inverter module having power semiconductor switches. The gate electrodes of the power semiconductor switches are driven directly by the control device. The inverter module is connected on the input side to a DC source and on the output side to the three-phase drive motor. Between the DC source and the inverter module there is a DC circuit, wherein drive signals that can be modulated on the DC circuit can be generated by the control device, and the inverter module has a demodulator, by which demodulator the drive signals can be converted into control voltages assigned to the individual gate electrodes of the power semiconductor switches.

A semiconductor device of an embodiment includes: a first trench located in a silicon carbide layer extending in a first direction; a second trench and a third trench adjacent to each other in the first direction; n type first silicon carbide region; p type second silicon carbide region on the first silicon carbide region; n type third silicon carbide region on the second silicon carbide region; p type fourth silicon carbide region between the first silicon carbide region and the second trench; p type fifth silicon carbide region between the first silicon carbide region and the third trench; p type sixth silicon carbide region shallower than the second trench between the second trench and the third trench and having a p type impurity concentration higher than that of the second silicon carbide region; a gate electrode in the first trench; a first electrode, and a second electrode.

A drive control method and system for controlling an inverter during power disruptions in the operation of an elevator drive includes the steps of predetermining whether a hoist motor of the elevator drive will be operating in a motor mode, a balanced mode or a regenerative mode on commencement of the power disruption, and controlling the inverter in accordance with the predetermined operating mode after commencement of the power disruption.