Abstract: A control apparatus for an elevator has a support device mounted on a car, a detection device for detecting the position of the car, and a control unit for controlling operation of the elevator based on information from the detection device. The support device has a rail holding member, which is displaceable with respect to the car and is guided by a guide rail located in a hoistway in which the car moves. The detection device is located on the rail holding member.

Abstract: To alleviate the ear block discomfort of passengers without causing any undue reduction in the operational efficiency of an elevator. A travel distance calculating section 13 calculates a travel distance of a car room 1 based on destination floor information 12a and a car position command signal 3a, and output travel distance information 13a to a speed pattern generating section 14. The speed pattern generating section 14 compares the travel distance with a predetermined distance, generates a speed pattern 14a of a normal operation if the travel distance is short, and generates the speed pattern 14a of a partially low speed operation if the travel distance is long. The predetermined distance indicates a difference in height corresponding to a difference in air pressure that causes the Eustachian tube to open against ear block discomfort by a passenger. A speed control section 24 makes the car room 1 move up and down based on the speed pattern 14a.

Abstract: In an elevator device, a drive unit has a drive sheave, a motor for rotating the drive sheave, and a motor driving portion for driving the motor. The motor driving portion is controlled by a control unit. When a car is running, the control unit monitors a load on at least one component within the drive unit, and generates a control command regarding a running speed of the car in accordance with a state of the load, and outputs the control command to the motor driving portion.

Abstract: A method for restricting the output of an electrical drive and for protection of an elevator are provided. The electrical drive includes a motor as well as a power supply appliance of the motor. In the method for restricting the output of an electrical drive the stator voltage vector is restricted to its limit value restricting only the component of the stator voltages in the direction of the q axis. In the protection of an elevator, the elevator includes a machinery brake, a safety brake of the elevator car, and also an electrical drive. The protection method includes determination of at least one limit value, restriction of the output of the electrical drive on the basis of at least one determined limit value, and restriction of the movement of the elevator car on the basis of at least on determined limit value.

Abstract: A set of elevators includes a plurality of elevators without counterweight, a power supply, and a common control system. The plurality of elevators has a common connection to the power supply. The common control system includes one or more instructions to prevent or delay dispatch of an elevator car stopped at a floor if, at that instant, within a set period of time, or at that instant and within the set period of time, power consumed from an associated electrical network by the set of elevators or fed into the associated electrical network by the set of elevators together exceeds a set value. A method for controlling a set of elevators includes determining whether power consumed together exceeds a set value, and when the power consumed exceeds the set value, then departure of a next elevator car to be dispatched is prevented or delayed.

Abstract: An elevating machine control apparatus controls an inverter (4) to drive an AC motor (5) connected to the inverter (4) with AC power, and energizes a power generation braking resistor (13) to apply a brake during regenerative operation of the AC motor (5). The apparatus prohibits the elevating machine from starting operating and interrupts power supply to the power generation braking resistor (13) if the DC stage voltage of the inverter (4) has a ripple quantity of a set value or more when the elevating machine is being stopped. Alternatively, the apparatus commands the elevating machine to stop operating and interrupts power supply to the power generation braking resistor (13) if the DC stage voltage of the inverter (4) during regenerative operation is a reference value or less when the elevating machine is in operation.

Abstract: The present invention provides an elevator controller including: a main control unit for controlling running of an elevator, in which the main control unit predictively calculates a continuous temperature state of a predetermined componential equipment of the elevator and performs an operation control of the elevator based on the predicted temperature state such that the componential equipment is not overloaded. Accordingly, a temperature rise in the componential equipment is suppressed, thereby enabling to prevent the elevator from becoming inoperable.

Abstract: In addition to the construction of a typical elevator control device in which power generated during regenerative operation is dissipated by a resistance chopper (18), an elevator control device is newly provided with: an electric double layer capacitor (21) connected in parallel with the DC capacitor (3) that smoothes the DC ripple of the rectifier circuit (2) that rectifies the AC power of the AC power source (1) and having an electrostatic capacitance that is considerably larger than this DC capacitor; a voltage detection circuit (22) that detects the terminal voltage of this electric double layer capacitor; and a drive control unit (5) that uses a voltage in the vicinity of the rated voltage of the electric double layer capacitor as the operating voltage of resistance chopper and, when the terminal voltage detected by a voltage detection circuit reaches the voltage in the vicinity of the rated voltage of the electric double layer capacitor, operates and controls the resistance chopper.

Abstract: The invention discloses a method for restricting the output of an electrical drive, and also a protection of an elevator. The electrical drive comprises a motor as well as a power supply appliance of the motor. In the method for restricting the output of an electrical drive the stator voltage vector is restricted to its limit value restricting only the component of the stator voltage in the direction of the q axis. In the protection of an elevator, the elevator comprises a machinery brake, a safety brake of the elevator car, and also an electrical drive. The protection of an elevator comprises a determination of at least one limit value, a restriction of the output of the electrical drive on the basis of at least one determined limit value, and also a restriction of the movement of the elevator car on the basis of at least one determined limit value.

Abstract: In an elevator apparatus, a single car is raised and lowered by a plurality of hoisting machines. An elevator control device for controlling the hoisting machines generates speed commands separately for the hoisting machines. When a current value of one of the hoisting machines reaches a current set value, which is set in advance during acceleration of the car, the elevator control device applies the speed command for that one of the hoisting machines, whose current value has reached the current set value, to the other hoisting machine as well.

Abstract: An elevator system in which a controller monitors whether or not a speed of an ascending/descending body reaches a preset overspeed. At a time of maintenance work, a stopper is interposed between a buffer and the ascending/descending body to limit a lowered position of the ascending/descending body. Stopper detection means detects installation of the stopper onto at least one of the buffer and the ascending/descending body. When the stopper is detected by the stopper detection means, the controller lowers a set value of the overspeed.

Abstract: An elevator system (20) includes a propulsion power assembly (38) with a power rating below that required to move a fully loaded elevator car (22) using a contract or design motion profile. One example propulsion power assembly (38) uses more than one motion profile based upon existing load conditions. One example uses a first motion profile including a first power parameter limit for load conditions at or below a selected load threshold that is less than a maximum load capacity of the car (22). The propulsion power assembly (38) uses a second motion profile with a lower power parameter limit for other load conditions. In one example, electrical current is the power parameter selected as a decision parameter dictating which profile to select based on an existing load. Another example propulsion power assembly (38) selects at least one of a speed limit or an electrical current limit based on an existing load and maintains a speed to stay within the selected limit.

Abstract: A car is suspended by suspension means and raised and lowered by means of a hoisting machine. Electric power supplied to a motor of the hoisting machine is controlled by an electric power converter. The electric power converter is controlled by means of a control apparatus. The control apparatus estimates a maximum value of a regenerative voltage at time of a regenerative operation of the hoisting machine when the car is running. When the estimated maximum value of the regenerative voltage reaches a predetermined voltage limit value, the control apparatus controls the electric power converter so as to stop an increase in estimated maximum value of the regenerative voltage.

Abstract: A control device for a rotating machine driving an elevator suppresses increases in the moving time of the elevator while securing control and stability in accordance with moving direction and load of a car of the elevator. A control device for controlling speed of the rotating machine without using a speed sensor includes a speed command signal generator for generating a rotational speed command for the rotating machine; and a speed sensor-less controller for controlling a voltage applied to the rotating machine without using a speed sensor, based on the rotational speed command from the speed command signal generator. In the control device, the speed command signal generator changes an acceleration running curve in a deceleration interval in accordance with the moving direction and the load of the car of the elevator to generate the rotational speed command.

Abstract: A control apparatus for an elevator has a speed command issuing portion, a movement control portion, and an acceleration limiting portion. The speed command issuing portion calculates a speed command for controlling a speed of a car. The movement control portion controls a movement of the car based on the speed command. The acceleration limiting portion compares drive information corresponding to an output of a drive device during the movement of the car with a preset limit value to determine whether or not an acceleration of the car can be increased. The speed command issuing portion calculates, based on information from the acceleration limiting portion, a speed command to stop the acceleration from increasing when the drive information reaches the limit value.

Abstract: In an elevator apparatus, a single car is raised and lowered by a plurality of hoisting machines. An elevator control device for controlling the hoisting machines generates speed commands separately for the hoisting machines. When a current value of one of the hoisting machines reaches a current set value, which is set in advance during acceleration of the car, the elevator control device applies the speed command for that one of the hoisting machines, whose current value has reached the current set value, to the other hoisting machine as well.

Abstract: The present invention provides an elevator speed governor that improves elevator service by exploiting the full use of motor capacity. In one embodiment of the present invention, an elevator speed governor for an elevator in which an elevator car (1) is attached to one end of a rope (2) having a counterweight (3) on the other end and driven by a motor (5) via the rope (2) comprises a motor current detector (15) that detects a motor current of the motor (5), a target speed determining section (11) that determines a target speed in accordance with the motor current detected by the motor current detector (15), and a motor control section (13) that controls the motor (5) so that the elevator car (1) moves at the target speed determined by the target speed determining section (11).

Abstract: A speed control method of an elevator-purpose comprising previously calculating an elevating distance in such a case that the elevator passenger car is decelerated from a reference frequency up to a leveling frequency in a constant deceleration speed, when the induction motor is stopped. The elevator passenger car is driven in a constant speed at an intermediate frequency so that the previously calculated distance becomes equal to an elevating distance when the elevator passenger car is decelerated at the constant deceleration speed from an arbitrary frequency up to the leveling frequency so as to adjust the elevating distance. The elevator passenger car is automatically decelerated at the constant deceleration speed up to the leveling frequency.

Abstract: An elevator control device that drives a cage in a high-efficient speed pattern without using a load detector such as a conventional scale device. The elevator control device includes: a current detector for detecting a current that is supplied to a motor from an inverter; a speed detector for detecting a rotation speed of the motor; a speed pattern generator for generating an elevator speed pattern; a motor speed control device for controlling the speed so that a speed detection value follows a speed command value of the speed pattern; and a motor current control device for controlling a current that is supplied to the motor with respect to the inverter by using a current detection value and the speed detection value on the basis of the speed command value.

Abstract: The invention relates to a speed monitoring method in a automation system for a conveyor installation, particularly for a pit. A speed monitoring method is provided that eliminates the need for detection elements for determining position that are arranged along the path of conveyance. An actual path value and an actual speed value are determined by means of at least one pulse counter. The actual path value is used for reading out a speed limiting value from a data table, which is stored in the automation system and which represents a stepped limiting value curve and for comparing the actual speed value with the read out speed limiting value.

Abstract: In an elevator apparatus, a car ascends and descends based on a running speed pattern generated by a control panel. Destination floor buttons and landing buttons are connected to an over speed monitoring portion without the intervention of the control panel. The over speed monitoring portion has an over speed setting portion for setting first and second over speeds based on car position information obtained from a car position detector and call registration information obtained from the destination floor buttons and the landing buttons. In the over speed setting portion, a running speed pattern different from the running speed pattern generated by the control panel is independently generated without depending on information from the control panel. The first and second over speeds are set based on the running speed pattern generated by the over speed setting portion.

Abstract: In an elevator apparatus, a control device obtains car information including at least one of car position information and car speed information based on a main detection signal from a main sensor unit. An auxiliary sensor unit detects arrival of a car at a preset reference position with in a hoistway to generate an auxiliary detection signal. The control device makes corrections to the car information based on the auxiliary detection signal.

Abstract: A control apparatus for an elevator has a speed command issuing portion, a movement control portion, and an acceleration limiting portion. The speed command issuing portion calculates a speed command for controlling a speed of a car. The movement control portion controls a movement of the car based on the speed command. The acceleration limiting portion compares drive information corresponding to an output of a drive device during the movement of the car with a preset limit value to determine whether or not an acceleration of the car can be increased. The speed command issuing portion calculates, based on information from the acceleration limiting portion, a speed command to stop the acceleration from increasing when the drive information reaches the limit value.

Abstract: An elevator control device for controllably driving multiple traction units includes position sensors and current supplies. Each of the current supplies includes a position controller for generating a speed command for the corresponding traction unit based on input difference between a common position command for the traction units and a feedback signal derived from an output of the pertinent position sensor, a speed controller for generating a current command for the corresponding traction unit based on an input difference between the speed command generated by the position controller and a feedback signal obtained by differentiating the output of the pertinent position sensor, and a current controller for supplying an electric current to the corresponding traction unit based on the current command generated by the speed controller.

Abstract: A drive, a method of operating the drive and an elevator operated by the drive for the movement of persons or goods by at least one car utilize a linear motor. The drive includes at least one linear motor with a secondary part positioned between a first primary part and a second primary part. The drive also includes at least one compensation device that acts by a compensating normal force against an attractive normal force between each of the primary parts and the secondary part.

Abstract: The invention relates to a condition monitoring method and a corresponding system for measuring the stopping accuracy of an elevator car. In the invention, a door zone is defined for each floor, a door zone detector is mounted on the elevator car, the elevator car is moved towards a destination floor, acceleration values of the elevator car are measured during its travel towards the destination floor by means of an acceleration sensor attached to the elevator car and the distance of the stopped elevator from the edge of the door zone is calculated on the basis of the measured acceleration values.

Abstract: A traction arrangement comprises a track, a carriage, guide means guiding the carriage along the track with a predetermined carriage/track gap, and eddy current means generating eddy current across the gap giving rise to a traction force. Such an arrangement has utility in ropeless elevator systems.

Abstract: Method for performing an elevator rescue run in an emergency situation, the elevator comprising and elevator car, a counter weight, a rope suspending the car and the counterweight, a drive motor, an emergency brake for stopping the car in an emergency situation, and a motor drive unit for supplying drive power to and for controlling the drive motor, having the following rescue run sequence steps: (a) operating the motor drive unit in a zero speed demand mode for holding the car at its present position; (b) lifting the brake, while holding the car in the zero speed demand mode; (c) determining the preferred movement direction of the car based on the power data as obtained by the motor drive unit; and (d) performing the rescue run in the direction of the determined preferred movement direction.

Abstract: An elevator car and counterweight system is provided with a variable drag element. The variable drag element is controlled such that the lower of the counterweight and the car has a higher drag against further movement. In an embodiment which is particularly useful in a 2:1 roping system, the sheaves (54, 58) associated with the counterweight (56) and the car (60) receive a braking/drive motor (62, 64) to provide the variable drag. While the present invention provides the variable drag to compensate for vertical differences between the counterweight and car, the invention can also be utilized to hold the car at a particular floor. Further, this invention can be utilized to address a counterweight or car jump situation. Another disclosed drag element may be a magnetizable member (40, 33) guided along a guide rail (34, 36) for each of the car (32) and the counterweight (38). A control controls the magnetic force associated with the guide elements to hold the car or prevent counterweight jump.

Abstract: A method for controlling at least two variable frequency drives connected in parallel. The method comprises, for each variable frequency drive, communicating a magnetizing current component value to a master controller, and receiving a speed demand, a flux demand, and an average magnetizing current component value from the master controller. The method also comprises determining a motor speed and a motor flux based on measurements of a stator voltage and current of a motor coupled to the variable frequency drive, determining a speed reference based on a torque current component value, and determining a flux reference based on the magnetizing current component value and the average magnetizing current component value. The method further comprises adjusting a torque current component based on the speed reference and/or adjusting a magnetizing current component based on the flux reference.

Abstract: A method and a system for controlling an elevator that does not change the torque direction, such as an elevator without counterweight. The elevator has an alternating-current electric motor (M1), such as a permanent magnet motor or an asynchronous motor, and a motor drive section (DRIVE1) for controlling the motor and an elevator control section (ECO1) used to control the operation of the elevator. Control channels are provided between the elevator control section and the motor drive section for the transmission of control signals. To control the motor, only position and torque control signals are passed between the elevator control section and the motor drive.

Abstract: A method and apparatus for stopping an AC motor that is controlling a load while detecting mechanical brake slippage of a mechanical brake for holding the load against movement includes a controller for decreasing torque-producing current commands from the drive while a speed regulator is commanding zero speed, sensing movement of the load while the speed regulator is commanding zero speed, detecting movement of the load past a pre-determined distance limit, and increasing torque to support the load and prevent further movement of the load. The controller will again decrease torque-producing current commands from the drive, and again checking for movement of the load, and upon sensing no load movement upon reaching zero torque, then shutting off the motor.

Abstract: Method and system of controlling a counterweightless elevator system provided with an elevator car and a variable speed drive with an electric motor. The elevator car load is weighed, and the elevator system is controlled in order to reduce the physical/electrical dimensions of the system. The total mass of the elevator is defined by the equation Mtotal=Mcar (mass of the car)+A*Maxpayload, wherein Mcar is the mass of the car, A is a coefficient and Maxpayload is the maximal payload. If the payload supercedes A*Maxpayload the elevator is controlled so that the speed and/or acceleration of the motor is reduced, and/or the idle time of the elevator is increased.

Abstract: A method of operating an elevator system with a drum for taking up a suspension device, a drive unit for driving the drum, and a control unit for controlling the drive unit, includes operating the control unit of the drive unit to prescribe a rotational speed that depends on a length of the suspension device that is rolled onto the drum. Also included is an elevator system in which the method can be used.

Abstract: A vibration controller controls vibrations generated in a driven object included in a system subject to vibrations due to the dynamic unbalance or eccentricity of a rotating member driven for rotation by an electric motor. An angular position transforming unit (45) and an angular velocity transforming unit (47) transform the output signal of a rotating motion measuring means (C1) into an angular position and an angular velocity, respectively. A sine calculating unit (55) calculates the sine of an angle obtained by adding up the angular position and a predetermined phase angle provided by a phase adjusting unit (49) by an adder (53). A multiplier (61) calculates the product of the output of a gain adjusting unit (57) that multiplies the output of the sine calculating unit (55) by a predetermined gain and the output of a multiplier (59) that calculates the square of the angular velocity. Again adjusting unit (57?) multiplies the output of a sine calculating unit (55?) by a predetermined gain.

Abstract: An elevator control method is provided, where the elevator motor is controlled in such manner that the velocity of the elevator follows a speed reference. When the elevator is decelerating, the motor is controlled by a speed adjustment method during the initial deceleration phase, and during the final deceleration phase the motor is controlled by a position adjustment method. The instant of transition from speed adjustment to position adjustment is determined substantially using the elevator speed curve.

Abstract: A method and an apparatus for adjustment of the rotor angle of an elevator motor (M), in which method: the rotor angle of the elevator motor is measured, the rotor angle is adjusted by using the measured rotor angle value as feedback data, and the rotor angle is measured by a pulse emitter (PE) or tachometer connected to the elevator motor. In the method, a disturbance signal (u) is fed into the rotor angle feedback data to produce a change (disturbance) in the rotor angle, the change (disturbance) is compared to the disturbance signal (u), and, on the basis of the comparison, a control signal is generated to adjust the rotor angle.

Abstract: A double deck elevator including a winding machine which lifts up/down a cage frame loaded with two cages in a vertical direction, a cage driving unit which changes a relative distance between upper and lower cages, and a cage position controller which starts an inter-cage distance adjustment operation of the cage driving unit almost at the same time when the winding machine is shifted from an acceleration operation to a constant velocity operation, and changes an operating velocity of the inter-cage distance adjustment operation corresponding to a destination floor almost at the same time when the winding machine changes from the constant velocity operation to a deceleration operation after the destination floor is determined, whereby completing the inter-cage distance adjustment operation almost at the same time when the winding machine stops.

Abstract: A method for intelligent control includes an exchange of historical parameters of events for operating a system and operating a hoist where an electric motor, preferably a DC-motor, is used for lifting and lowering a lifting belt. It can take place at different speeds by registering amperage through the motor and to perform a switching between fast and slow speed when a given current level is reached. The change in hoisting/lowering speed is achieved when a control unit changes the voltage supplied by the battery unit to the DC-motor or changes the frequency of power supply to an AC-motor. The method makes it possible to control the system and to optimize the hoisting/lowering speed for the lifting belt depending on the load thereon.

Abstract: A safety device for monitoring a movable element, in particular, for elevators, is provided. The safety device includes a speed determination unit for determining the speed of the movable element, a comparator device for comparing a predetermined speed with the determined, actual value, a triggering unit for triggering a braking device, and a distance determination unit for determining the distance of the movable element in relation to a stationary or movable target. The comparator device comprises a memory for storing a maximum admissible speed and at least one nominal distance with an associated nominal speed. The comparator device compares a greatest stored nominal distance with an actual distance indicated by the distance determination unit. When the nominal distance is the same as the actual distance, the comparator device compares the nominal speed associated with the nominal distance with the actual speed registered by the speed determination unit at this point of time.

Abstract: A drive, a method of operating the drive and an elevator operated by the drive for the movement of persons or goods by at least one car utilize a linear motor. The drive includes at least one linear motor with a secondary part positioned between a first primary part and a second primary part. The drive also includes at least one compensation device that acts by a compensating normal force against an attractive normal force between each of the primary parts and the secondary part.

Abstract: An elevator apparatus has a criterion (overspeed levels) that changes in accordance with an operational condition of a car. The elevator apparatus also has a position information correcting means that corrects an error in value that determines the criterion. In the elevator apparatus, the overspeed levels are determined using continuous information corresponding to car position, while the continuous information is corrected using intermittent information corresponding to actual car position. According to the elevator apparatus, on-the-spot adjustment or long-time maintenance becomes unnecessary, and overspeed detection levels can easily be changed in accordance with the operation conditions of the car.

Abstract: When there is a breakdown in either one of first and second power converters supplying electrical power to a multi-winding motor comprising a wind-up mechanism, a rescue operation can be safely and reliably carried out by using the remaining power converter. A wind-up mechanism comprises a two-winding motor having first and second windings, and, during normal operation, power is supplied to the first and second windings from first and second inverters respectively. When the first inverter has broken down due to excessive current, first and second contactors are switched off, and a third contactor comprising a short-circuiting unit is switched on. Consequently, both windings receive power from the second inverter, enabling the rescue operation to be carried out without causing vibrations.

Abstract: Method for controlling the drive of a conveyor device (10), especially in the form of an escalator or moving sidewalk, switchable between load operation and no-load operation, having a drive motor (26) and a frequency changer (42) controllable at least with respect to frequency and phase position of its output voltage, in which the drive motor (26) in load operation is fed with a line voltage with essentially constant line frequency and in no-load operation with the frequency changer output voltage, the phase difference between the phase position of the line voltage and the phase position of the frequency changer output voltage is determined, the phase position of the frequency changer output voltage is corrected according to the determined phase difference and therefore essentially brought into agreement with the phase position of the line voltage and switching is produced as soon as this agreement is reached.

Abstract: Method of detecting obstructions encountered by a motorized door. The method includes providing a signal processor with one or more signals indicative of a predetermined door trajectory profile for at least a segment of a stroke of the door, the door trajectory profile providing an ideal speed and/or position versus an elapsed time since a beginning of the segment of the stroke. A door position signal from a position encoder for the door is received into the signal processor. The method includes generating one or more signals indicative of the velocity and/or position of the door from the door position signal and generating a trajectory discrepancy signal based on the velocity and/or position in relation to the ideal speed and/or position. A motor control signal is generated based on the trajectory discrepancy signal and the motor control signal is connected to motor control circuits connected to drive the motor for the door.

Abstract: An elevator system in which an elevator-car and a counter weight are suspended on a pulley system in a hoistway. The elevator system includes a receiving unit for receiving an electric power from a feeding unit provided in the hoistway, an inverter for converting the received electric power into ac power, a motor connected to an ac side of the inverter for driving the counter weight in up and down directions, a sensor for detecting a position of the receiving unit, and a control unit for controlling an inverter on the basis of the position detected by the position sensor. The counter weight carries the receiving means, the inverter, and the motor.

Abstract: The hoist control device controls the hoist in such a manner that once the speed change of the cage frame has accelerated at a fixed acceleration, constant speed is maintained, after which it decelerates at a fixed deceleration and stops. Meanwhile, the cage chamber position control device controls the cage chamber drive device in such a manner that once the speed change of the cage chamber driven by the cage chamber drive device has accelerated at a fixed acceleration, constant speed is maintained, after which it decelerates at a fixed deceleration and stops.

Abstract: An apparatus for controlling an operation of an elevator includes a power supply unit for detecting whether the main power supply was supplied including a charger and for outputting a predetermined control signal, an operation control unit for receiving the control signal from the direct current power supply unit and a demand control signal inputted by a user and for outputting a speed control signal and a load compensation signal so as to control the elevator system, a power consumption detector for computing a power consumption of the alternating current motor, a speed limiter for limiting a speed of the motor upon receipt of the alternating current motor speed signal from the speed detector and the power consumption of the motor computed by the power consumption detector, and a speed control unit for controlling a rotational speed of the alternating current motor upon receipt of the load compensation signal and the control signal from the speed limiter.

Abstract: A velocity instruction generating apparatus for a car of an elevator system and a velocity instruction generating method which make it possible to decrease a computation time, computation amount and computation error by computing a velocity instruction based on an integer number computation and control the velocity of the car in real time.

Abstract: The present invention relates to a leveling control device for an elevator system which estimates a load torque applied to an axis of an alternating current motor on the basis of a torque current component and a rotation angle of the alternating current motor, while carrying out a level compensation operation, and which compensates the torque current component for the difference between the estimated load torque and the load compensation torque by an output signal from a load detector, which results in an improved speed control property in the level compensation operation of the elevator system.