JP4232618B2 - Elevator control device and elevator system - Google Patents

Description

  The present invention relates to an elevator control device suitable for an emergency stop test operation of an elevator and an elevator system including the same.

  Generally, a motor control device including an inverter device such as a PWM (Pulse Width Modulation) inverter using a switching element such as a power transistor or an IGBT (Insulated Gate Bipolar Transistor) is used as an elevator control device. The motor torque required for normal elevator operation is about 250% of the rated torque, and the capacity of the PWM inverter (capacity of the switching element) is preferably designed with a current required to generate this 250% torque. .

  On the other hand, there is an emergency stop device for a car as one of safety devices in an elevator. This is a device that grips the guide rail and stops the car from rising or falling when the speed of the car is abnormally increased compared to the rated speed for some reason. It is necessary to check the performance of the emergency stop device at the time of completion of the elevator and periodically. At this time, the motor needs a torque of 300 to 400% of the rated torque. Therefore, in order to generate this torque, a current of 300 to 400% of the rated current flows according to the torque, and the switching element of the PWM inverter needs to have a capacity that can withstand this. For this reason, the apparatus size and cost of a PWM inverter increase.

  In order to solve such problems, the elevator is normally operated using the first excitation current command, and when a large torque (current) is required as in the emergency stop test operation, the first excitation current is used. A method of controlling an induction motor using a large second excitation current command is known (see, for example, Patent Document 1). Further, as a method for obtaining the same effect, a method of controlling the induction motor by switching the slip frequency smaller during the emergency stop test operation than during the normal operation is known (for example, see Patent Document 2).

  Further, as a different approach, a method is known in which the winding of the induction motor is switched from the Δ connection to the Y connection during the emergency stop test operation (see, for example, Patent Document 3).

Japanese Patent Publication No. 6-13394 Japanese Patent Publication No.7-86068 JP-A-6-135653

  In recent years, synchronous motors using small and powerful permanent magnets as field magnets are becoming mainstream in elevator drive motors instead of induction motors. In this permanent magnet type synchronous motor, since the field is always established by the permanent magnet, the excitation current corresponding to the field of the induction motor is not required, but the relationship between the torque and the magnitude of current is excited like the induction motor. It cannot be changed by setting value of current and slip frequency.

  Further, since the permanent magnet type synchronous motor does not slide, the current in the motor stop state becomes a direct current amount. For this reason, at the time of an emergency stop test operation, a big burden is applied to a specific switching element compared with an alternating current. Even when the motor windings are switched, this DC current problem remains.

  In view of the above problems, an object of the present invention is to provide an elevator capable of performing an emergency stop test operation without increasing the capacity of an inverter device or the capacity of a switching element when a permanent magnet type synchronous motor is used for an elevator driving motor. It is providing the control apparatus of this, and an elevator system provided with the same.

In the elevator control device and the elevator system according to the present invention, the permanent magnet synchronous motor detects a change of winding for generating a larger torque than that in the normal operation during the emergency stop test operation. The switching frequency of the inverter device that drives the synchronous motor is set to a value lower than that during normal operation , and the current control gain is set to a smaller value than during normal operation .

  ADVANTAGE OF THE INVENTION According to this invention, even when a permanent magnet type synchronous motor is used for the motor for an elevator drive, a direct-current large current can be sent without imposing a burden on the switching element of an inverter apparatus. For this reason, the emergency stop test operation can be performed without increasing the capacity of the inverter device or the switching element.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows an elevator system according to an embodiment of the present invention.

In FIG. 1, the PWM converter 52 boosts the AC voltage from the AC power supply 51 to a predetermined DC voltage based on the operation command from the converter control device 80 and charges the capacitor 53.
The PWM converter 52 is controlled by the operation command of the converter control device 80 so that the outputs of the DC voltage detector 81 and the current detector 82 become predetermined values. The charged DC voltage Vdc is converted into a variable voltage / variable frequency AC voltage by the PWM inverter 54. The output of the PWM inverter 54 is supplied to a permanent magnet type synchronous motor (PMSM) 56 (hereinafter referred to as “synchronous motor 56”), whereby the synchronous motor 56 is driven at a variable speed. A motor permanent magnet position detector 57, a speed detector 58, a brake device (not shown), and an elevator sheave 2 are connected to the output rotating shaft of the synchronous motor 56. A car 1 and a counterweight 3 are suspended from the sheave 2 via a rope 4 wound around the sheave 2. An emergency stop device 6 is installed in the car 1. With this configuration, the car 1 moves up and down according to the rotation of the synchronous motor 56, that is, the rotation of the sheave 2.

  The emergency stop device 46 is provided with a rail 5 (a guide rail for the car) that guides the car 1 according to the excessive speed of the car 1 when the car 1 is abnormally accelerated compared to the rated speed. ) To prevent the car 1 from rising and falling.

The speed command means 61 generates a speed command ω ^* for the synchronous motor. The speed control means 62 performs feedback control so that the speed ω from the speed detector 58 follows the speed command ω ^*, and outputs the torque command T ^* to the q-axis current command means 63 via the torque command limiter 67. . The q-axis current command unit 63 calculates a current corresponding to the torque command T ^* and outputs the q-axis current command Iq ^* to the current control unit 65 via the q-axis current command limiter 68. Thus, the motor command overshoot when the synchronous motor 56 is activated can be suppressed by the torque command limiter 67 and the q-axis current command limiter 68. In the current control means 65, the current i from the current detector 55 is changed so that the current corresponding to the q-axis current command Iq ^* and the d-axis current command Id ^* output from the d-axis current command means 64 flows to the synchronous motor 56. The voltage command v ^* is output to the PWM pulse generating means 66 through feedback. Here, in the synchronous motor 56, since the magnetic flux is always established by the permanent magnet, the d-axis current command Id ^* corresponding to the exciting current of the induction motor is set to zero. That is, the ratio between the magnitude of the torque generated by the synchronous motor 56 and the magnitude of the q-axis current command Iq ^* is constant. The PWM pulse generating means 66 creates a PWM pulse signal corresponding to the voltage command v ^* and outputs it to the PWM inverter 54. The PWM pulse period, that is, the switching frequency fc of the PWM inverter is set by an emergency stop test mode setting means described later. The normal operation of the elevator is performed by controlling the speed of the synchronous motor 56 in this way.

  Next, the operation in the emergency stop test operation will be described.

  As described above, in the emergency stop test operation, a torque exceeding the normal operation is required. On the other hand, it is only necessary to confirm that the sheave 2 slips, so that the required speed is low. Therefore, the windings of the synchronous motor 56 are switched to improve the ratio of torque to current.

FIG. 2 is a diagram showing the wiring connection of the synchronous motor 56. FIG. 2A is a connection diagram during normal operation, and FIG. 2B is a connection diagram during emergency stop test operation. It is composed of one set (terminal names U2, V2, W2) connected in advance to the Y connection (also referred to as “star connection”) and U1-X1, V1-Y1, W1-Z1 windings independent of it. . During normal operation, X1, Y1, and Z1 are connected to create a neutral point, and U1 and U2, V1 and V2, and W1 and W2 are connected to form a double Y connection. On the other hand, during the emergency stop test operation, a single Y connection is established by connecting X1, U2, Y1, V2, Z1, and W2, respectively. As a result, the magnetic flux generated when a predetermined current (total current of the double winding in the case of the double Y connection) flows in the windings of each phase is larger in the single Y connection than in the double Y connection. Doubled. Therefore, in the single Y connection, the ratio of torque to current can be improved to about twice that of the double Y connection. In addition, as long as the magnetic flux with respect to a predetermined electric current can be increased, not only a Y connection but another connection form may be sufficient.

  After switching the windings of the synchronous motor 56 in this way, an emergency stop test operation is performed. Specifically, the inside of the car 6 is unloaded and the emergency stop device 6 is operated. Next, after the operation of the flowchart of FIG. 3 to be described later, the synchronous motor 56 is rotated in the direction in which the car ascends or descends, and it is confirmed that the sheave 2 has slipped, that is, idled.

FIG. 3 is a flowchart showing the operation of the winding state determination means 71 and the emergency stop test mode setting means 70 in FIG. Each step will be described.
step1
The winding state determination means 71 controls the PWM inverter 54 to the synchronous motor 56, applies a measurement voltage, and measures the impedance Z of the motor. The impedance Z of the motor is calculated by Z = V ^* / I by taking the current I flowing through the motor when a predetermined voltage V ^* is generated by the PWM inverter 54 from the current detector 55 in the winding state determination means 71. . The impedance to be measured may be either a resistance value or an inductance value, or both.
step2
As can be seen from the connection diagram of FIG. 2, the impedance between the motor terminals of the single Y connection during the emergency stop test operation is four times larger than the double Y connection during the normal operation. This is because the impedance of the motor means that the inductance of one winding (for example, U1-X1) in the connection diagram of FIG. This is because it is 4L, and the other double Y connection (for example, between the terminals U1 (U2) and V1 (V2)) is L because it is parallel to 2L. Using such a difference in impedance, the winding state determination means 71 compares the measured value Z of step 1 with the impedance value (L) at the time of double Y connection stored in advance, and the measured value Z If is larger, proceed to step 3. That is, the winding state determination unit 71 outputs a command signal for causing the emergency stop test mode setting unit 70 to change the setting of various control parameters or stop the operation of the PWM converter, as will be described later. If the measured value is equal to or smaller than the value at the time of double Y connection, it is considered that the emergency stop test operation is not ready, and the process ends without changing each limiter of the torque command and current command described later. When the process is finished, an alarm indicating that the emergency stop test operation is not ready may be activated or a lamp may be turned on.
step3
The emergency stop test mode setting means 70 changes the following settings in order to perform the emergency stop test operation so that the switching element of the PWM inverter operates normally even when a large DC current is passed. First, the switching frequency fc of the PWM inverter 54 is set to a value lower than that during normal operation, and the set value is output to the PWM pulse generating means 66. For example, fc is preferably about ¼ or less, such as about 8 kHz during normal operation and about 2 kHz during emergency stop test operation. Thereby, the switching loss of the PWM inverter 54 can be significantly reduced (for example, 1/4 or less).

  Next, a signal Cstop for stopping the boosting operation of the PWM converter 52 is output to the converter control device 80. The operation of the switching element of the PWM converter 52 is stopped by the signal Cstop, and the PWM converter 52 is set to a diode rectification operation by a diode connected in reverse parallel to the switching element, so that the DC voltage Vdc is a peak value of the AC power supply 51. Can be reduced. For example, Vdc = 720V when the switching element of the PWM converter 52 is operating, but when the Cstop signal is output, Vdc = 600V. Thereby, the switching loss of the PWM inverter 54 can be further reduced.

Next, in order to generate a larger torque in the emergency stop test operation than in the normal operation, the limit values (TLM, IqLM) of the torque command T ^* and the q-axis current command Iq ^* are set larger than those in the normal operation. To do. For example, each limiter value is set to a value of about 250% or 500% during rated operation during normal operation and emergency stop test operation, respectively.

  Next, the current control gain (in the case of PI control: proportional gain Kp, integral gain Ki) of the current control means 65 is set to a smaller value than during normal operation. This is to prevent the current control system from becoming unstable due to an increase in the dead time of the current control system because the switching cycle becomes longer by lowering the switching frequency fc. For example, the crossing frequency of about 1000 rad / s during normal operation is set to about 250 rad / s during emergency stop test operation. Note that the response of the current control system is set high in order to reduce the current distortion due to the dead time of the PWM inverter in consideration of the ride comfort of the elevator in normal operation, but the ride comfort is considered in the emergency stop test operation. Since there is no need, low response is acceptable.

By providing the means as described above, the synchronous motor 56 can generate a large direct current required for the sheave idling. Moreover, the switching loss which generate | occur | produces in a switching element at the time of an emergency stop test operation can be reduced significantly.

  The present invention is not limited to the above-described embodiments, and various embodiments and modifications can be made within the scope of the technical idea of the present invention. For example, for the inverter device and the converter device, various modulation methods other than PWM (pulse width modulation) can be used, and either a voltage type or a current type may be used. Furthermore, a diode rectifier may be used instead of the converter device. In this case, the above-mentioned Cstop signal becomes unnecessary.

The figure which shows the elevator system by one Embodiment of this invention. The figure which shows the connection of the coil | winding of a synchronous motor. The flowchart which shows operation | movement of a winding state determination means and an emergency stop test mode setting means.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Car, 2 ... Sheave, 3 ... Counter weight, 4 ... Rope, 5 ... Guide rail, 51 ... AC power supply, 52 ... PWM converter, 53 ... Smoothing capacitor, 54 ... PWM inverter, 55, 82 ... Current detector 56 ... Permanent magnet synchronous motor (synchronous motor), 57 ... Position detector, 58 ... Speed detector, 61 ... Speed command means, 62 ... Speed control means, 63 ... q-axis current command means, 64 ... d-axis current Command means 65 ... Current control means 66 ... PWM pulse generation means 67 ... Torque command limiter 68 ... q-axis current command limiter 70 ... Emergency stop test mode setting means 71 71 Winding state determination means 80 ... Converter Control device, 81... DC voltage detector.

Claims (4)

An elevator including an inverter device that drives a permanent magnet synchronous motor for driving an elevator, and having current control means for feeding back a current flowing through the permanent magnet synchronous motor and outputting a voltage command for controlling the inverter device A control device,
Winding state detection means for detecting reconnection of the winding for generating a torque larger than that during normal operation during the emergency stop test operation, and the permanent magnet type synchronous motor;
When the winding state detection means detects switching of the winding, the switching frequency of the inverter device is set to a value lower than that during the normal operation , and the current control gain of the current control means is set to normal. Emergency stop test mode setting means for setting a smaller value than during operation ,
Elevator control device.   2. The converter according to claim 1, further comprising a converter device that supplies DC power to the inverter device, wherein the emergency stop test mode setting unit detects that the winding state detection unit detects switching of the windings. Furthermore, an elevator control device that outputs a command to stop the boosting operation of the converter device. A permanent magnet synchronous motor;
A sheave driven by the permanent magnet synchronous motor;
A car and a counterweight suspended from the sheave via a rope;
Including an inverter device that outputs the applied voltage of the permanent magnet type synchronous motor at a variable voltage and variable frequency for raising and lowering the car, and feeding back the current flowing through the permanent magnet type synchronous motor to control the inverter device A control device comprising current control means for outputting a voltage command for
An emergency stop device that operates in response to an excessive speed of the car and prevents the car from rising or falling;
With
The controller is
Winding state detection means for detecting reconnection of the winding for generating a torque larger than that during normal operation during the emergency stop test operation, and the permanent magnet type synchronous motor;
When the winding state detection means detects switching of the winding, the switching frequency of the inverter device is set to a value lower than that during the normal operation , and the current control gain of the current control means is set to normal. Emergency stop test mode setting means for setting a smaller value than during operation ,
Elevator system with   4. The control device according to claim 3, further comprising a converter device for supplying DC power to the inverter device, wherein the emergency stop test mode setting means is configured such that the winding state detecting means is connected to the winding. An elevator system that further outputs a command to stop the boosting operation of the converter device to the converter device when detecting the above.

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