A method for operating a lift system includes a lift cage movably housed movably inside a lift shaft. A linear drive is configured to drive the lift cage, the linear drive includes a stator arrangement fixedly attached to the lift shaft with a plurality of stators and a rotor attached to the lift cage. The stator arrangement includes electromagnetic coils, each of the coils configured to be operated by one phase of a polyphase alternating current. The method includes providing the polyphase alternating current to operate the stator arrangement and thereby drive the lift cage to generate an upward force for the lift cage, monitoring a deceleration value of the lift system with sensors that are permanently installed in the lift shaft, and switching the linear drive into a safety operating state when the deceleration value above a predefined threshold value is determined by way of said monitoring.

A regenerative elevator drive (2) is arranged to receive power from, and supply regenerative energy to, an external power supply (4, 10) and is arranged to direct excess regenerative energy through a dynamic braking resistor (20). An inverter (16) is arranged to receive a DC voltage, derived from the external power supply (4, 10), and to convert the DC voltage to an AC voltage for output to an external motor (22). A DC link capacitor (14) is connected across the input of the inverter (16). A circuit breaker unit (54) is arranged to switch between a first state which provides a connection between the inverter (16) and the external power supply (4, 10), and a second state which disconnects the inverter (16) from the external power supply (4,10).

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 regenerative drive (30) and method for providing power from such to at least one auxiliary power supply (41, 43) is disclosed. The drive may include a converter (32) and an inverter (34) connected by a DC bus (33), and a controller (54) configured to apply at least one of unipolar modulation and bipolar modulation to the converter (32) and the inverter (34), and to provide about half of the output voltage across the upper portion (130) of the DC bus (33) and about half of the output voltage across the lower portion (136) of the DC bus (33), when the upper and lower portions (130, 136) of the DC bus (33) are unevenly loaded. A first auxiliary power supply (41) may be connected to one of the upper and lower portions (130, 136) of the DC bus (33) and may receive power from the multilevel regenerative drive (30).

An electric linear motor and an elevator are presented. The electric linear motor includes a stator beam including at least two stators rails, and a number of movers configured to move with respect to the stator beam. Each mover includes at least two motor units configured to be arranged next to the stator beam such that each one of the motor units faces one of the stator rails, and each one of the at least two motor units includes at least two independently controllable motor subunits arranged consecutively with respect to a longitudinal direction of the motor unit. Each of said motor subunits includes windings for generating a magnetic field to form a magnetic coupling between the motor subunit and the respective stator rail.

An electric linear motor, an elevator and a method for controlling rotation of a mover with respect to a stator beam are presented. The electric linear motor includes a number of stator beams, wherein at least one of them includes stators extending in a longitudinal direction of the beam. The motor also includes a number of movers, wherein at least one them includes armatures, wherein each armature is adapted for establishing an electromagnetic coupling with a corresponding stator for moving the mover. The motor also includes an air gap regulator for regulating movement of the mover with respect to the stator beam, wherein the air gap regulator includes guide element(s) arranged for limiting the rotation of the mover with respect to the stator beam.

An electric linear motor, an elevator and a method for controlling rotation of a mover with respect to a stator beam are presented. The electric linear motor includes a number of stator beams, wherein at least one of the stator beams includes a plurality of stators extending in a longitudinal direction of the stator beam, a number of movers, wherein at least one of the movers includes a plurality of armatures, wherein each one of the armatures is adapted for establishing an electromagnetic coupling with a corresponding one of the stators for moving the mover along said stator, and wherein at least one of the armatures is arranged to be offset from the aligned position with respect to the corresponding one of the stators in a perpendicular direction relative to the longitudinal direction.

A monitoring system for controlling self-testing of a traction elevator includes a self-testing process module in communication with a back-up battery power supply. The self-testing process module includes a processor configured to initiate and control a series of steps for performing measurements of the back-up battery power supply, including measurements of the battery supply during a simulated emergency situation (rescue/evacuation). The processor is programmed to initiate testing on a defined schedule and transmit test results to a maintenance system (including remotely-located systems) on a routine basis. The monitoring system also includes a display unit providing visual information regarding the status of self-testing processes and their results and a communications unit for transmitting test results to a remote maintenance controller.

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.

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.