JP2007119100A - Control device for elevator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for an elevator detecting reduction of electrostatic capacity of a smoothing capacitor without being affected by a power source characteristic of a building facility. <P>SOLUTION: The control device for the elevator is provided with a converter 2 for converting an alternating current from an A.C. power source to a direct current; the smoothing capacitor 3; an inverter 4 for converting the smoothed direct current to the alternating current; a D.C. voltage detection circuit 11 for detecting a voltage value of the smoothing capacitor; a series connection body of regeneration resistance 9 for consuming the regeneration electric power from an electric motor and a semiconductor element 10; and a control circuit 12 for controlling the inverter to convert the regeneration electric power to the direct current in regeneration operation, turning ON the semiconductor element to consume the regeneration electric power by the regeneration resistance when a detection voltage value by the D.C. voltage detection circuit is higher than a predetermined first reference voltage value, turning OFF the semiconductor element when it is lower than a second reference voltage value lower than the first reference voltage value and detecting a reduction ratio of an electrostatic capacity of the smoothing capacitor based on the ON time or the OFF time of the semiconductor element. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an elevator control device driven by an electric motor via an inverter.

  Conventionally, alternating current supplied from an alternating current power source is converted to direct current by a converter, the converted direct current is smoothed by a smoothing capacitor, and the smoothed direct current is converted to alternating current of an arbitrary voltage and frequency by an inverter to drive the motor. In the elevator control apparatus for raising and lowering the elevator car, the capacitance of the smoothing capacitor is detected by detecting a DC voltage, and the electrostatic capacitance of the smoothing capacitor is detected according to the magnitude of the ripple voltage included in the detected DC voltage. Some have determined a decrease in capacity (for example, see Patent Document 1).

  According to such an elevator control device, since the DC voltage is detected and the decrease in the electrostatic capacitance of the smoothing capacitor is determined based on the magnitude of the ripple voltage included in the DC voltage, there is no need for human operation. It can be determined whether the capacitance has dropped, and the smoothing capacitor's capacitance can be quickly detected, and changes in the smoothing capacitor's capacitance can be monitored constantly or at a relatively short time interval. Can be improved.

JP-A-8-157152

  However, since the above-described conventional capacity reduction detection means detects during powering operation, it tends to cause errors depending on the power supply characteristics of the installed building equipment.

  The present invention has been made to solve the above-described problem, and an object of the present invention is to provide an elevator control device that is less affected by power supply characteristics of building equipment and the like to detect a decrease in the capacitance of a smoothing capacitor. And

  An elevator control apparatus according to the present invention includes a converter that converts alternating current supplied from an alternating current power source into direct current, a smoothing capacitor that smoothes direct current converted by the converter, and direct current smoothed by the smoothing capacitor. An inverter for controlling a motor for driving a car by converting to an alternating current of voltage and frequency, a voltage detection means for detecting a voltage value of the smoothing capacitor, and a regenerative electric power connected to the direct current side of the inverter A series connection body of a regenerative resistor and a semiconductor switch for consuming electric power, and at the time of regenerative operation of the electric motor, the inverter is controlled to convert regenerative power into direct current, and based on the detected voltage value by the voltage detecting means When the detected voltage value is higher than the predetermined first reference voltage value, the semiconductor switch is turned on to regenerate. And a control circuit that controls the semiconductor switch to turn off when the detected voltage value is lower than a second reference voltage value that is lower than the first reference voltage value. The reduction rate of the capacitance of the smoothing capacitor is detected based on the on time or off time of the semiconductor switch.

  According to the present invention, the control circuit detects the rate of decrease in the capacitance of the smoothing capacitor based on the on-time or off-time of the semiconductor switch, thereby affecting the capacity of the smoothing capacitor on the power supply characteristics of the building equipment and the like. There is an effect that it can detect without receiving.

Embodiment 1 FIG.
1 is a block diagram showing an overall configuration of an elevator control apparatus according to Embodiment 1 of the present invention.
The elevator control device shown in FIG. 1 includes a converter 2 that converts alternating current supplied from an alternating current power source 1 into direct current, a smoothing capacitor 3 that smoothes the converted direct current, and the smoothed direct current at an arbitrary voltage and frequency. The inverter 4 that controls the electric motor 5 that converts the alternating current to drive the car 8, the regenerative resistor 9 that is connected to the direct current side of the inverter 4 and consumes the regenerative power from the electric motor 5, and the semiconductor element as a semiconductor switch 10, a DC voltage detection circuit 11 for detecting a DC voltage smoothed by the smoothing capacitor 3, and during regeneration operation of the electric motor 5, the inverter 4 is controlled to convert the regenerative power into DC, and the DC voltage And a control circuit 12 that controls on / off of the semiconductor element 10 based on a voltage value detected by the detection circuit 11. 6 represents a hoisting machine, and 7 represents a counter.

  Here, as will be described later, the control circuit 12 turns on the semiconductor element 10 to regenerate regenerative power when the detection voltage value by the DC voltage detection circuit 11 is higher than a predetermined first reference voltage value. When the resistor 9 is consumed and the detected voltage value is lower than the second reference voltage value lower than the first reference voltage value, the semiconductor element 10 is controlled to be turned off. The reduction rate of the capacitance of the smoothing capacitor 3 is detected based on the off time.

Next, the operation of the elevator control apparatus according to the above configuration will be described.
The AC power source 1 is converted to DC by the converter 2, smoothed by the smoothing capacitor 3, and supplied to the inverter 4. The inverter 4 converts the supplied direct current into alternating current and supplies it to the electric motor 5. These components are controlled by the control circuit 12, whereby the electric motor 5 is driven and the car 8 moves up and down.

  On the other hand, the DC voltage detection circuit 11 detects the DC voltage smoothed by the smoothing capacitor 3 and sends it to the control circuit 12. Further, the electric power regenerated during the regenerative operation of the electric motor 5 is converted into direct current by the inverter 4 by the operation of the control circuit 12. At this time, the control circuit 12 turns on the semiconductor element 10 according to the voltage value detected by the DC voltage detection circuit 11 and consumes the regenerative power through the regenerative resistor 9.

Next, FIG. 2 shows the voltage Vpn (t) across the smoothing capacitor 3 when the electric motor 5 is operated at a constant regenerative speed.
In FIG. 2, Ton is the ON time of the semiconductor element 10, Toff is the OFF time of the semiconductor element 10, Vpn1 is the voltage value (first reference voltage value) of the smoothing capacitor 3 at the moment when the semiconductor element 10 changes from OFF to ON, Vpn2 indicates the voltage value (second reference voltage value) across the smoothing capacitor 3 at the moment when the semiconductor element 10 changes from on to off.

  Considering a state in which the semiconductor element 10 is turned off at the time of regenerative constant speed operation, the regenerative power from the inverter 4 is only charged to the smoothing capacitor 3, so that the regenerative power per unit time during constant speed traveling is obtained. When the power is P, the relationship between the off time Toff of the semiconductor element 10 and the capacitance C of the smoothing capacitor 3 is expressed by the following equation.

  Therefore, if the regenerative power P is constant, the off time Toff is proportional to the capacitance C of the smoothing capacitor 3.

  Next, a state in which the semiconductor element 10 is turned on during regenerative constant speed operation will be considered. The energy charged in the smoothing capacitor 3 is obtained by using the capacitance C and the value Vpn1 of the moment Vpn (t) at which the semiconductor element 10 changes from off to on, the regenerative power P, and the resistance plant R of the regenerative resistor 9, It is expressed as follows.

  Solving this for Vpn (t),

Thus, when the equations are summarized as Vpn (Ton) = Vpn2, the following equation is obtained.

  Therefore, if the regenerative power P is constant, the ON time Ton is also proportional to the capacitance C of the smoothing capacitor 3.

  As described above, the time Ton when the semiconductor element 10 is turned on and the time Toff when the semiconductor element 10 is turned off during the regenerative constant speed operation are proportional to the capacitance C of the smoothing capacitor 3, and thus the semiconductor element during the regenerative constant speed running in the initial state. 10 operation times (off time or on time or total thereof) were stored, and the operation time was calculated by comparing the current operation time of the semiconductor element 10 measured in the same load state as that in the initial state measurement. The decrease rate of the operation time of the semiconductor element 10 is equal to the decrease rate of the capacitance C of the smoothing capacitor 3. By this method, the rate of decrease in the capacitance C of the smoothing capacitor 3 is detected, and when a decrease beyond a specified level is detected, it can be determined that the life of the smoothing capacitor 3 has been reached. It is also possible to detect the lifetime by designating in advance the operating time of the semiconductor element 10 considered to have a lifetime according to the capacitance C of the smoothing capacitor 3 to be used.

  Therefore, according to the first embodiment, the control circuit 12 turns on the semiconductor element 10 when the DC voltage value becomes higher than the predetermined first reference voltage value during the regenerative operation, and is lower than the first reference voltage value. Since the semiconductor element 10 is turned off when the voltage becomes lower than the second reference voltage value, and the rate of decrease in the capacitance of the smoothing capacitor 3 is detected based on the on time or the off time, the capacity of the smoothing capacitor 3 is changed to the building equipment. Thus, there is an effect that detection can be performed without being affected by the power supply characteristics.

  In the first embodiment, the rate of decrease in the capacitance of the smoothing capacitor 3 is detected based on the on-time or off-time of the semiconductor element 10. However, the load on the car load provided in the car 8 is determined. Is provided, and the reduction rate of the capacitance of the smoothing capacitor 3 can be detected in consideration of the weight value. Similarly, current detection means for detecting the value of the current flowing through the electric motor 5 is provided, and the reduction rate of the capacitance of the smoothing capacitor 3 can be detected in consideration of the current value. By doing so, it is possible to accurately detect the rate of decrease in the capacitance of the smoothing capacitor.

1 is a block diagram showing an overall configuration of an elevator control device according to Embodiment 1 of the present invention. FIG. It is a voltage waveform diagram of the smoothing capacitor 3 shown in FIG.

Explanation of symbols

  1 AC power supply, 2 converter, 3 smoothing capacitor, 4 inverter, 5 electric motor, 6 hoisting machine, 7 counter, 8 cage, 9 regenerative resistor, 10 semiconductor element, 11 DC voltage detection circuit, 12 control circuit.

Claims (3)

A converter that converts alternating current supplied from an alternating current power source into direct current;
A smoothing capacitor for smoothing the direct current converted by the converter;
An inverter that converts the direct current smoothed by the smoothing capacitor into alternating current of an arbitrary voltage and frequency and controls a motor for driving a car;
Voltage detecting means for detecting a voltage value of the smoothing capacitor;
A series connection body of a regenerative resistor and a semiconductor switch connected to the DC side of the inverter and consuming regenerative power from the electric motor,
During regenerative operation of the electric motor, the inverter is controlled to convert regenerative power into direct current, and the detected voltage value is higher than a first reference voltage value determined in advance based on a detected voltage value by the voltage detecting means. When the semiconductor switch is turned on, regenerative power is consumed by the regenerative resistor, and when the detected voltage value is lower than the second reference voltage value lower than the first reference voltage value, the semiconductor switch is turned off. And a control circuit that
The said control circuit detects the decreasing rate of the electrostatic capacitance of the said smoothing capacitor based on the ON time or the OFF time of the said semiconductor switch. The control apparatus of the elevator characterized by the above-mentioned. In the elevator control device according to claim 1,
The control circuit stores an off time, an on time, or a total thereof as the operation time of the semiconductor switch at the time of regenerative constant speed running in the initial state, and the load state is the same as when the stored operation time and the initial state are measured. An elevator control device, wherein a rate of decrease in the capacitance of the smoothing capacitor is detected based on a decay rate of the operating time of the semiconductor switch calculated by comparing the measured operating time of the semiconductor switch. . The elevator control device according to claim 2,
The control circuit of the elevator, wherein the control circuit determines that the life of the smoothing capacitor is a lifetime when a reduction rate of the capacitance of the smoothing capacitor is reduced more than a specified value.

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