A safety torque off (STO) device interrupts torque generation by an elevator installation drive machine supplied by a power supply device being part of an inverter device, for example. The STO device includes a control input, signal input terminals connected to signal generation device outputs and signal output terminals connected to driver circuit inputs. Each of the STO signal input terminals is electrically connected to an associated one of the signal generation device outputs via first and second signal transmission switches connected in series. The control input is connected to first and second control units, wherein the first control unit, controlled by a control signal applied to the control input, switches switching states of all the first signal transmission switches and the second control unit, controlled by a control signal applied to the control input, switches switching states of all of the second signal transmission switches.

An electrical converter unit and a method for reducing thermal stress of a power semiconductor switch, such as an IGBT, of an electrical converter unit, the electrical converter unit comprising at least a gate control circuit wherein the electrical converter unit controls an electrical motor. The method comprises determining load and estimating required motor current based on the determined load and/or a predetermined speed profile. The electrical converter unit has at least a first operating state and a second operating state. The second operating state is used if predetermined criteria is fulfilled, the predetermined criteria relating to at least one of the following: estimated required current, measured motor speed, temperature of the power semiconductor switch and/or electrical converter unit, temperature model of the power semiconductor switch and/or electrical converter unit. In the second operating state a lower switching frequency of the power semiconductor switch is used than in the first operating state, and in the second operating state a higher switching speed of the power semiconductor switch is used than in the first operating state.

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 extending in a first direction in a silicon carbide layer; a second trench and a third trench adjacent to each other in the first direction; a first silicon carbide region of n type; a second silicon carbide region of p type on the first silicon carbide region; a third silicon carbide region of n type on the second silicon carbide region; a fourth silicon carbide region of p type between the first silicon carbide region and the second trench; a fifth silicon carbide region of p type between the first silicon carbide region and the third trench; a gate electrode in the first trench; a first electrode, part of which is in the second trench, the first electrode contacting the first silicon carbide region between the fourth silicon carbide region and the fifth silicon carbide region; and a second electrode.

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 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.

A power supply circuit of a passenger conveyor converts includes an electrolytic capacitor and a control power supply device configured to supply an electric power to a charging circuit configured to charge the electrolytic capacitor. A storage battery is disposed between a converter and an inverter in parallel with the electrolytic capacitor. When an operation of the passenger conveyor is stopped in response to a key operation, the power supply to the control power supply device is shut off. When the operation of the passenger conveyor is resumed in response to a key operation, a DC electric power charged in the storage battery is supplied to the inverter, to thereby allow the passenger conveyor to resume the operation.

A method for determining a rotor position of an electric motor, an elevator and an electrical converter unit are presented. The method comprises supplying a first excitation signal to the electric motor, determining a first response signal generated in the motor in response to the first excitation signal, determining, based on the first response signal, an electrical angle of a direct axis of the motor with respect to a stationary reference frame, supplying a second excitation signal to the motor, wherein the second excitation signal is based on the determined electrical angle, determining a second response signal generated in the motor in response to the second excitation signal, and determining the rotor position based on the second response signal.

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.

The present invention relates to a conveyor system comprising: a drive machine, a conveyor control unit configured to control operation of a conveyor device, a sensor array comprising at least one sensor mounted to the drive machine and adapted to measure one or more properties of the drive machine, a processing unit associated with the drive machine, wherein the processing unit is connected to the sensor array and configured to obtain and process measurement data from the sensor array to generate in-formation about an operation of the drive machine, and a communication channel between the conveyor control unit and the processing unit. The conveyor system may be an elevator system, an escalator system or a moving walk system.