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 power management system for an elevator system includes a power converter having input terminals coupled to an AC power source supplying AC power to the power management system and output terminals coupled to a common DC bus, the power converter configured to convert the AC power from the AC power source into DC power on the common DC bus and vice versa; an AC load coupled to the input terminals of the power converter; a second power source for supplying DC power to the common DC bus; a power inverter configured to invert the DC power on the common DC bus into AC output power for driving an electric motor of the elevator system; and a controller configured to detect a failure of the AC power source.

An energy storage system is provided including: an elevator; an elevator motor; a power system coupled to the elevator motor. The power system including at least one capacitor operable to store energy received form the elevator motor and to supply stored energy to the elevator motor; and at least one flywheel operable to store energy received from the elevator motor and to supply stored energy to the elevator motor.

An arrangement and a method for changing a direction of movement of an elevator car of an elevator, and the elevator thereof, are presented. The arrangement comprises at least two rotatable first stator beam parts for receiving at least two movers rotatably coupled to the elevator car and at least one actuator for rotating the at least two first stator beam parts. Said stator beam parts are arranged such that the axes of rotation of said stator beam parts align with the axes of rotation of the movers when the movers are arranged at corresponding positions. Each one of the movers rotates along with a respective first stator beam part when said respective first stator beam part is being rotated by the at least one actuator.

Provided is a control device for an elevator, including: a first power converter; a second power converter; and switching means. The switching means being configured to selectively achieve: a first circuit configuration that causes the first power converter to operate as the regenerative converter, and also causes the second power converter to operate as the inverter; and a second circuit configuration that causes the second power converter to operate as the regenerative converter, and also causes the first power converter to operate as the inverter.

A conveyance system includes an alternating current (AC) power source (28), a machine (30) for moving a conveyance apparatus, and a regenerative drive (20). The machine is connected to the AC power source by the regenerative drive. The regenerative drive includes a direct current (DC) bus (26), a converter (22) and a machine control circuit (24). The conveyance system further includes an energy harvesting device (32) and a switching arrangement (34). The switching arrangement (34) is arranged between the energy harvesting device (32) and the machine control circuit (24), and is switchable between a first condition, in which the energy harvesting device (32) is disconnected from the machine control circuit (24), and a second condition in which the energy harvesting device (32) is operatively connected to at least one switching device of the second plurality of switching devices (23) of the machine control circuit (24).

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 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.

Disclosed are a motor control system and a motor control method that allow the balance of evaluation values in a trade-off relationship to be easily adjusted. The motor control system includes: an inverter (5) that applies AC voltage to a motor (1); a control unit (3, 4) that generates a voltage command for AC voltage in response to a control command; and a feedback unit (6, 7, 8) that applies a correction value to the control unit. The feedback unit estimates a plurality of evaluation values from a state quantity using a plurality of regression formulas, where at least one state quantity (x1, x2) of the motor is an input variable and a plurality of evaluation values (y1, y2) of the motor or a motor-driven object (2) are output variables, calculates an evaluation function with the estimated plurality of evaluation values as arguments, and generates a correction command on the basis of a calculation value resulting from the evaluation function.

An energy storage system is provided including: an elevator; an elevator motor; a power system coupled to the elevator motor. The power system including at least one capacitor operable to store energy received form the elevator motor and to supply stored energy to the elevator motor; and at least one flywheel operable to store energy received from the elevator motor and to supply stored energy to the elevator motor.