Apparatus for controlling an A-C power elevator

• US 4,545,464 A
• Filed: 03/01/1983
• Issued: 10/08/1985
• Est. Priority Date: 03/09/1982
• Status: Expired due to Term

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Nomura, Masami
• Primary Examiner(s): Shoop, Jr., William M.
• Assistant Examiner(s): Ip, Shik Luen Paul
• Application Number:
  US06/470,955
• Time in Patent Office: 952 Days
• Field of Search: 187/29, 187/29 R, 318/762, 318/798, 318/802, 318/803, 318/807, 318/808, 318/810, 318/811, 363/37, 363/55, 363/61
• US Class Current: 187/296
• CPC Class Codes: B66B 1/30 effective on driving gear , e.g. acting on power electronics, on inverter or rectifier controlled motor
• CPC Class Codes: H02M 5/458 using semiconductor devices only
• CPC Class Codes: H02P 23/06 Controlling the motor in four quadrants

Abstract

An apparatus for controlling an A-C powered elevator in which A-C electric power is converted into D-C electric power through a rectifier, the D-C electric power thus converted is converted into a A-C electric power of a variable frequency via an inverter, an A-C electric motor is driven by the thus converted A-C electric power, the A-C motor being controlled by a controller which is connected to a D-C control source, a cage is driven by the thus controlled electric motor, said motor producing regenerated electric power depending upon the operation condition of said cage, wherein provision is made of a regenerated electric power controlling device which is connected between the D-C side of the inverter and the controller in order to supply the regenerated electric power to the controller. When the voltage on the D-C side of the inverter becomes greater than a predetermined reference value, a switching element is rendered conductive, and the regenerated electric power is supplied to the controller. Therefore, a power regenerating inverter need not be independently provided, and the apparatus can be cheaply constructed. Further, since the electric power is not wastefully consumed, energy can be saved.

Claims

1. An apparatus for controlling an A-C powered elevator comprising a rectifier for converting A-C electric power to D-C electric power, an inverter connected to the rectifier for converting the D-C electric power to A-C electric power of a variable frequency, a cage, an A-C electric motor operatively associated with the cage and connected to the inverter to be driven by the variable frequency A-C electric power, the motor producing regenerated electric power depending on the operation conditions of the cage, means for controlling the A-C electric motor, a D-C source connected to the motor controlling means, and a regenerated electric power controlling device connected between the D-C side of the inverter and the motor controlling means in order to supply the regenerated electric power to the motor controlling means.

2. The apparatus of claim 1 wherein the regenerated electric power controlling device includes a power controller which produces a switching signal when the voltage on the D-C side of the inverter exceeds a reference value and a switching element which is connected between the D-C side of the inverter and the motor controlling means, is further connected to the power controller, and is rendered conductive by the switching signal in order to supply the regenerated electric power to the motor controlling means.

3. The apparatus of claim 2 wherein the regenerated electric power controlling device further includes a diode connected in parallel with the switching element.

4. The apparatus of claim 3 wherein the regenerated electric power controlling device further includes a resistor connected between the switching element and the inverter.

5. The apparatus of claim 1 wherein the regenerated electric power controlling device includes a power controller which produces a switching signal when the voltage of the D-C source exceeds a reference value, a resistor connected to the D-C side of the inverter, and a switching element which is connected via the resistor to the D-C side of the inverter, is further connected to the power controller, and is rendered conductive by the switching signal so that the regenerated electric power is consumed by the resistor.

6. The apparatus of claim 1 wherein the regenerated electric power controlling device includes a power controller which produces a first signal when the voltage on the D-C side of the inverter exceeds a first reference value and produces a second signal when the voltage of the D-C source exceeds a second reference value, a first switching element which is connected between the D-C side of the inverter and the motor controlling means, is further connected to the power controller, and is rendered conductive by the first signal in order to supply the regenerated electric power to the motor controlling means, a resistor, and a second switching element which is connected in series with the resistor to the D-C side of the inverter via the first switching element, is further connected to the power controller, and is rendered conductive by the second signal so that the regenerated electric power is consumed by the resistor.

7. The apparatus of claim 6 wherein the regenerated electric power controlling device further includes a resistor connected between the first switching element and the inverter and wherein the first and second switching elements and the motor controlling means are connected at a common point.

8. The apparatus of claim 6 wherein the inverter includes a plurality of arms connected in parallel with each other, each arm comprising a set of switching elements connected in series and diodes connected in parallel with each switching element, wherein the first and second switching elements are connected in series at a common point, and wherein diodes are connected in parallel with each of the first and second switching elements whereby the first and second switching elements and their associated diodes constitute another arm similar to the arms of the inverter.

9. The apparatus of claim 1 wherein the regenerated electric power controlling device includes a power controller which produces a first signal when the voltage on the D-C side of the inverter exceeds a first reference value and produces a second signal when the voltage of the D-C source exceeds a second reference value, a first switching element which is connected between the D-C side of the inverter and the motor controlling means, is further connected to the power controller, and is rendered conductive by the first signal so that the regenerated electric power is supplied to the motor controlling means, a resistor connected to the D-C side of the inverter, and a second switching element which is connected to the D-C side of the inverter via the resistor, is further connected to the power controller, and is rendered conductive by the second signal so that the regenerated electric power is consumed by the resistor.

10. An apparatus for controlling an A-C powered elevator comprising a rectifier for converting A-C electric power to D-C electric power, a capacitor connected to the rectifier for smoothing the D-C electric power, an inverter connected to the capacitor for inverting the smoothed D-C electric power to A-C electric power of a variable frequency, a cage, an A-C electric motor operatively associated with the cage and connected to the inverter to be driven by the variable frequency A-C electric power, the motor producing regenerated electric power depending on the operating conditions of the cage, means for controlling the A-C electric motor, a D-C source connected to the motor controlling means, a power controller which produces a switching signal when the A-C power is interrupted, a resistor connected to the D-C side of the inverter, and a switching element which is connected via the resistor to the D-C side of the inverter, is further connected to the power controller, and is rendered conductive by the switching signal so that the electric charge stored in the capacitor is consumed by the resistor.