JPH04207992A - Power conversion equipment for elevator - Google Patents

Abstract

PURPOSE:To suppress the occurrence of overvoltage by giving a control command for continuously and gradually reducing a gate voltage, taking in and storing an abnormal signal from a current detector provided for each self-arc- extinguishing element, judging an abnormal mode and storing the results of the judgment. CONSTITUTION:A gate circuit 12 operates a photocoupler PC-2 by an abnormal signal from a detector 17. By the operation of the photocoupler PC-2, the base voltage VB of a transistor Q4 rises slowly, then the transistor Q4 is operated, the gate voltage VGE of IGBT4-1 is decreased slowly and continuously. This will act to slowly decrease the collector current Ic of the IGBT. Thus, the peak value VCEp of the voltage VCE between the collector and emitter is able to suppress the rising voltage VCE to a low level without exceeding element withstand voltage VCEmax thereby protecting without the occurrence of a failure of element.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a power conversion device for an elevator.

In particular, the present invention relates to a protection method for an elevator power converter configured with a field-effect self-extinguishing element.

[Conventional technology]

As described in Japanese Unexamined Patent Publication No. 1-23166, the conventional device lowers the gate voltage of a field effect self-extinguishing element to a value lower than the normal gate voltage in response to an abnormal signal from an abnormal current detection means. It was controlled in steps.

[Problem to be solved by the invention]

The above-mentioned conventional technology does not give sufficient consideration to sudden changes in current due to sudden changes in gate voltage, resulting in the problem of overvoltage generation. In addition, since the structure is not designed to identify the circuit or element conflict that caused the overcurrent, overcurrent is likely to occur repeatedly in the same abnormal mode, and there are problems such as thread stress accumulating in the element and causing element destruction. Ta.

The purpose of the present invention is to solve the above-mentioned problems in the prior art,
It is an object of the present invention to provide a highly reliable elevator power conversion device that can suppress the occurrence of overvoltage and can prevent repeated failures by identifying a circuit or element that has caused an abnormality.

[Means to solve the problem]

In order to achieve the above object, the present invention provides an inverter configured to include a group of field-effect self-extinguishing elements, which supplies alternating current power of a predetermined voltage and a predetermined frequency to an elevator drive motor, and a self-extinguishing device for these devices. A gate circuit that controls the gate voltage of the arc element, an arithmetic processing unit that gives a control command to the gate circuit, and current detectors provided at the input and output parts of the inverter and each of the self-extinguishing elements. A power converter for an elevator, comprising: a forward converter that converts AC power source power into DC power and supplies the DC power to the inverse converter; and a voltage detector that detects a power outage of the AC power source.

The arithmetic processing unit receives the abnormal signal from the current detector and the voltage galvanometer provided at the input and output parts of the inverter, and issues the control command to continuously and gradually decrease the gate voltage. The processing configuration is such that the abnormality signal is supplied to the gate circuit, the abnormality signal from the current detector provided for each self-extinguishing element is captured and stored, the abnormality mode is determined, and the determination result is stored.

Furthermore, in the second aspect of the present invention, when the forward converter in the first aspect of the present invention is also a forward converter constituted by a group of field-effect self-extinguishing elements, the input part and the output part of this forward converter A current detector is provided in each of the section and the self-extinguishing element, and the arithmetic processing unit includes current detectors on both the forward converter side and the inverse converter side, and a voltage detector that detects a power outage of the AC power supply. The configuration is such that the same processing as described above is performed in response to an abnormality signal from.

[Effect]

Abnormal current detectors installed at the input and output sections of the converter are
The collector current of the element is indirectly detected, and an abnormal signal is generated when it exceeds a predetermined value. Further, the voltage detector generates an abnormal signal when the AC power supply is interrupted and the voltage becomes below a predetermined value.

In response to these abnormal signals, the gate circuit controls the gate voltage to continuously and gradually decrease.

This works not only to suppress the collector current but also to suppress the generation of overvoltage by gradually changing the current.

On the other hand, the abnormal current detector provided for each element detects the voltage between the collector and emitter that is generated when an overcurrent flows through the element, and when it exceeds a predetermined value, the abnormal current detector is sent to an arithmetic processing device, such as a microprocessor. Send to computer. The arithmetic processing device stores this abnormality signal in the memory and can identify the abnormality mode by a predetermined determination.

[Example] Hereinafter, an example of the present invention will be described with reference to FIG. 1st
In the figure, 1 is a three-phase AC power supply, 2 is a forward converter that converts AC power to DC power, 3 is a capacitor that smoothes rectified DC power, and 4 is a converter of smoothed DC power to AC power of any voltage and frequency. 5 is an elevator drive motor rotated by the output of the inverter, 6 is a sheave connected to the drive motor, 7 is a main rope, 8 is a car, 9 is a balance weight, and 10 is the speed of the drive motor. encoder to detect,
11 is an arithmetic processing unit that controls the speed of the car; in the embodiment, it is a microcomputer (hereinafter referred to as microcomputer);
12 is a gate circuit that receives a control command signal from the microcomputer and drives the field-effect self-extinguishing elements 4-1 to 4-6 that constitute the inverter 4; 13 is an abnormality in the input current of the inverter 4; 14 is an inverse converter 4
An abnormal current detector on the output side that detects abnormalities in the output current.

15 is a power supply voltage abnormality detector for detecting a power outage of the three-phase AC power supply; 16 is an abnormality detector for various elevator equipment (not shown); and 18-1 to 18-6 are field-effect self-extinguishing elements 4-1 to 18-6. This is an abnormal current detector that detects an abnormal voltage between the collector and emitter when an overcurrent occurs in 4-6. Note that 17 and 19 are detectors that receive signals from the respective abnormality detectors, convert them into digital signals of a predetermined pattern, and transmit the digital signals to the microcomputer 11.

A three-phase AC power source 1 is converted into a DC voltage by a forward converter 2, smoothed by a capacitor 3, and applied to an inverse converter 4. Inverse converter 4
works like this:

The microcomputer 11 generates a speed command, and combines this speed command with
The actual speed of the drive motor 5 detected by the encoder 10 is compared, vector control calculations and PWM (pulse width modulation) control calculations are performed, and PWM pulses are output. The gate circuit 12 receives the + PWM pulse, amplifies the PWM pulse, and converts it into a field effect self-extinguishing element [hereinafter referred to as IGBT (In
Sulated Gate BipolarTrans
Apply a gate voltage to the gate of
The IGBT is driven and the inverter 4 is driven to output variable voltage, variable frequency three-phase AC power.

The drive motor 5 is speed-controlled by this three-phase AC power, and is driven through the sheave 6 by the main rope 7. Carts at both ends of the main rope8. The operation of the balance weight 9 is controlled.

By the way, an elevator is a transport machine that transports people in a car 8, and it is necessary to give sufficient consideration to equipment failure and reliability. Furthermore, as the buildings into which elevators are delivered become taller, their role as transport equipment becomes more important, and if a breakdown occurs, it is necessary to quickly restore the elevators.

Now, the inverse converter 4 is constituted by an IGBT with fast switching operation. When this IGBT is used, the switching operation is fast, so the chopping frequency can be increased to 10 KHz or more, which is highly effective in reducing the noise of the device and the drive motor.

However, there are problems such as the generation of excessive voltage due to the fast switching operation and the low withstand capability against excessive current. Therefore, in a system configuration using IGBTs, sufficient consideration must be given to these problems.

FIG. 2 is an example of a gate circuit that drives an IGBT, and FIG. 3 is a time chart of signals of each part to explain the protection operation of the IGBT. In FIG. 2, the gate circuit 12 receives a PWM pulse from the microcomputer 11 through a photocoupler PC-1. When the photocoupler PC-1 is on, the transistor Q8 is turned off, the transistor Q1 is turned on, and the gate voltage VGE is applied between the gate G and emitter 2 of the IGBT4-1, making the IGBT4-1 conductive. Collector current Ic flows.

Next, when photocoupler PC-1 is in OFF operation.

Transistor Q8 turns on, transistor Q1 turns off, transistor Q2 turns on, and IC, Br3-1
Gate voltage -VGE is applied between gate G and emitter 2 of , IGBT4-1 is non-conductive and collector current Ic
is blocked.

During such an operation, if IGBT 4-1 and IGBT 4-2 of inverter 4 become conductive at the same time for some reason, the potential of capacitor 3 will be short-circuited, and as shown in Fig. 3(a).
As shown in , the collector current Ic increases rapidly and IG
BT4-1. IGBT4-2 has a small current withstand capacity, so there is a risk of destruction, and the peak value of collector current Ic, Icp
It is necessary to suppress it as small as possible. Moreover, when this excessive current is turned off, the switching operation of the IGBT is fast, so the collector current Ic decreases sharply as shown at A in FIG. 3(a), and the current change rate dIC/dt increases.
The voltage generated between the circuit inductance and the circuit inductance is shown in Figure 3 (
It becomes excessive like A in f).

There is a risk that the element breakdown voltage V CE may exceed the a port and destroy the element.

In this way, consider the overcurrent withstand capacity and overvoltage withstand capacity when designing the collector current. need to be reduced immediately and gradually.

The protection operation will be explained below. Now, IGBT
is operating normally and the collector current Ic is flowing, but when IGBT4-1 and IGBT4-2 become conductive at the same time for some reason, the collector current Ic increases sharply as shown in Figure 3(a).
flows to cp. The current at this time is shown in Fig. 1 at capacitor 3. IGBT4-1. IGBT4-2. capacitor 3
flows along the route of Here, the abnormal current detector 13 in FIG.
Since the detection level is set to IC- in FIG. 3(a), an abnormality detection operation is performed at point D in FIG. 3(a), and an abnormality signal is transmitted to the detector 17. The detector 17 is the microcomputer 11
and sends an abnormal signal to the gate circuit 12. Gate circuit 1
2 operates the photocoupler PC-2 by the abnormal signal from the detector 17.

Due to the operation of the photocoupler PC-2, the base voltage VB of the transistor Q4' rises gradually as shown in FIG. 3(d), operating the transistor Q4, and IGBT4-
1+7) Set the gate voltage VGE as shown in FIG. 3(e),
Decrease slowly and continuously.

This means that the collector current Ic of the IGBT is
), it acts to gradually decrease the amount of water.

Therefore, the peak value VCEP of the voltage VCH between the collector and the emitter can suppress the rising voltage ΔVCE to a low value, as shown in B in FIG. You can protect yourself without getting too far.

Further, when a short circuit failure occurs on the load side of the inverter 4, it is detected by the output side abnormal current detector 14, and the same protective operation as described above can be performed.

Furthermore, if the power supply voltage is lost due to a power outage, it is detected by the power supply voltage abnormality detector 15, and the same protective operation as described above is performed.

In addition, the elevator drive system has various emergency operations, but by detecting each normal operation with the elevator equipment abnormality detector 16, the same protective operation as described above is performed.

Now, with the above-mentioned protective operation, it is possible to safely protect the device without causing destruction in the event of an abnormality such as a capacitor voltage short circuit or a load side short circuit. However, if it is not possible to identify the abnormality mode in which the above-mentioned protective operation was activated and remove the abnormality, there is a risk that the same abnormality will occur when the system is restarted, due to repeated overvoltage and overcurrent.

Stress accumulates in the element, and in the worst case, it may cause element destruction.

Therefore, an example of the abnormal mode determination means will be explained using FIG. 4, FIG. 5, and FIG. 6. FIG. 4 is a diagram showing an outline of processing within the microcomputer 11, and FIG.

FIG. 6 is a flowchart of abnormal mode determination processing. First, in FIG. 4, the detectors 17 and 19 each digitally process the inputted abnormal signal to produce a signal that can be identified according to the input (eg.

The abnormal signal from the input side abnormal current detector 13 is "oooo"
”, an abnormal signal from the output side abnormal current detector 14, etc.) and sends it to the microcomputer 11. When the microcomputer 11 receives the signal, it identifies the abnormal signal by processing F100O and sends it to the microcomputer 11. The data is stored in the RAM area.

Next, an abnormal mode is determined in process F2000.

The operation of abnormal mode determination will be explained using the flowcharts of FIGS. 5 and 6. In FIG. 5, when the F2000 starts up, it first checks whether an abnormal signal is received from the abnormal current detector 13. If there is a reception,
Upper and lower elements of any phase (for example, IGBT4-1 and 4-2
) is in short-circuit abnormal mode. (If no abnormal signal is received from the abnormal current detector 13, process F210 in FIG.
0 and check whether there is a load short circuit abnormality. ) Now, when the short-circuit abnormal mode of the element is confirmed, it is checked whether abnormal signals are received from the abnormal current detectors 18-1 to 18-6 of each phase. For example, if a continuity failure occurs for some reason, IGBT4
-1, if IGBT4-2 is turned on in this state, the R phase will be short-circuited and an excessive current will begin to flow, but the above-mentioned protective operation will suppress the overcurrent and overvoltage to a level that does not cause element destruction. Ru. If the abnormality detector 18
When abnormal signals are received from -1 and 18-2, determination processing is performed to determine the R-phase short-circuit abnormal mode, and similarly, when abnormal signals are received from 18-3 and 18-4, the S-phase short-circuit abnormal mode is determined.

When the determination is completed, each abnormality mode of the determination result is transferred to the RA.
Store in M.

Next, in FIG. 6, when process 2100 is activated,
Check whether an abnormal signal is received from the abnormal current detector 14. If it is not received, it is assumed that the abnormality detectors 18-1 to 18-6 provided for each element are malfunctioning, and the determination is terminated.

Now, when an abnormal signal is received, the process F2000 in FIG.
In the same way as the short-circuit abnormality mode determination processing procedure, each abnormality mode is determined based on a combination of abnormality signals from the abnormality detectors 18-1 to 18-6 provided for each element. In this load short-circuit abnormal mode, the upper and lower elements of each phase are not turned on at the same time (if the upper and lower elements are turned on at the same time, the above-mentioned short-circuit abnormal mode occurs), so six inspection modes are possible as shown in the figure. For example, when the R-8 phase on the load side is short-circuited due to some abnormality and the inverse converter 4 in FIG. An overcurrent flows through either R+ and S-1 or R- and S+, respectively. However, as described above, this overcurrent is suppressed to a level that does not cause element destruction by the above-mentioned protective operation.

When the determination of one of the six modes is completed, the determination result is stored in the RAM area.

In this way, by memorizing failure modes, not only is it highly effective in investigating the causes of abnormalities, but since the abnormality is identified, the root cause of the abnormality can be removed and repeated failures can be eliminated. be able to. Furthermore, the amount of time required to investigate the abnormality can be significantly reduced, and the downtime of the elevator can be shortened.

FIG. 7 is a configuration diagram of an embodiment corresponding to claim 2 of the present invention. This embodiment is different from the embodiment shown in FIG. However, each IGBT is also provided with an abnormality detector for detecting its own abnormal voltage, and abnormality signals from these detectors are transmitted to the microcomputer 11 via detectors 17 and 19.

With the above configuration, all IGBTs can be safely protected.

〔Effect of the invention〕

According to the structure of the first claim of the present invention, the IG of the inverse converter
According to the structure of the second claim, it flows to all the IGBTs of the inverse converter and the forward converter. Since excessive current can be reduced immediately and slowly and continuously, overvoltage will not be generated and the device will not be destroyed.

Furthermore, since the failure mode in the event of an abnormality is processed by a microcomputer and stored in memory, it is easy to investigate the cause, shorten the time required to recover from a failure, and provide highly reliable elevator power that does not cause repeated failures. A converter can be provided.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an embodiment of the present invention, FIG. 2 is a diagram showing details of the gate circuit in FIG. 1, FIG. 3 is a signal waveform diagram of each part for explaining the operation of the present invention, and FIG. FIG. 1 is a schematic diagram of the processing of the microcomputer, FIGS. 5 and 6 are flowcharts of the abnormality determination processing of the microcomputer in FIG. 1, and FIG. 7 is a configuration diagram of another embodiment of the present invention. 13... Input side abnormal current detector, 14... Output side abnormal current detector, 4-1 to 4-6... Field effect self-extinguishing element, 12... Gate circuit, 18-1 ~18-6・
...Element abnormality detector. Figure 2 Figure 3 also 4WJ /7, t9 7/ lips 5 τ 6th mouth

Claims (1)

[Claims] 1. A forward converter that converts AC power to DC power, a filter that smoothes its output voltage, and a field effect converter that converts this DC power to AC power of a predetermined voltage and a predetermined frequency. An inverter including a self-arc-extinguishing element group, an elevator drive motor connected to its output side, a gate circuit for controlling the gate voltage of the self-arc-extinguishing element group, and an operation for giving a control command to this gate circuit. In a power conversion device comprising a processing device, current detectors provided respectively at the input section and output section of the inverter and the self-arc-extinguishing element, and a voltage detector for detecting a power outage of the AC power supply. , the arithmetic processing device receives abnormal signals from the current detector and the voltage detector provided at the input section and the output section of the inverter, and issues the control command to continuously and gradually decrease the gate voltage. An elevator characterized in that it has a processing configuration that receives and stores an abnormal signal from a current detector provided for each of the self-extinguishing elements as well as a gate circuit, determines an abnormal mode, and stores the determination result. power converter. 2. The forward converter according to claim 1 is a forward converter that includes a group of field-effect self-extinguishing elements, and the input section and the output section of this forward converter, as well as the self-extinguishing elements, each receive a current. Detectors are provided, and the arithmetic processing unit includes a current detector provided at the input section and output section of the forward converter, a current detector provided at the input section and output section of the inverse converter, and an AC power source. In response to an abnormal signal from the voltage detector detecting a power outage, a control command for continuously and gradually decreasing the gate voltage is given to the gate circuit, and is provided for each self-extinguishing element of the forward converter. The present invention is characterized by a processing configuration that captures and stores an abnormal signal from a current detector provided for each self-extinguishing element of the inverse converter, determines an abnormal mode, and stores the determination result. Power conversion equipment for elevators.