Abnormality diagnosis device of regenerative resistor

Abstract

To detect abnormality of a regenerative resistor early and protect an elevator before reaching a critical failure.SOLUTION: An abnormality diagnosis device is connected to a power supply circuit of an elevator motor having a regenerative resistor arranged in a preceding stage of an invertor supplying power to a motor driving an elevator and consuming regenerative power from the motor, a switching element switching electric conduction to the regenerative resistor, and a reflux diode arranged in parallel to the regenerative resistor, and has a diagnosis current control unit for supplying diagnosis current to the switching element and energizing the regenerative resistor at the time of diagnosis of the regenerative resistor, a current measuring unit for measuring a current detection value flowing through the regenerative resistor at the time of diagnosis, and a deterioration determination unit for determining deterioration of the regenerative resistor by comparing the measured current detection value with a preset initial value, and executing abnormality diagnosis according to a degree of the deterioration.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] An embodiment of the present invention relates to an abnormality diagnosis device and an abnormality diagnosis method for a regenerative resistor. [Background technology]

[0002] When an elevator is in regenerative operation, a regenerative resistor is installed to absorb the regenerative power generated by the motor. The regenerative power is consumed by turning on a switching element connected to the regenerative resistor to pass a regenerative current through the regenerative resistor. If the regenerative power becomes too large, an overvoltage abnormality may occur, which may damage the regenerative resistor.

[0003] When a regenerative resistor has an internal wire made of a coil-shaped magnetic material, the wire vibrates when a switching current is applied, which can eventually cause the wire coil to deform, destroying the insulation that fills it and leading to a short circuit or ground fault.

[0004] Conventionally, methods for diagnosing an abnormality in a regenerative resistor include a method in which a regenerative resistance value is calculated from regenerative power or an applied voltage, and the calculated value is compared with a preset reference resistance value to determine whether an abnormality has occurred. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2009-142103 A [Patent Document 2] JP 2013-143830 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, while the conventional methods can determine that an abnormality has occurred, there is a problem in that it is difficult to determine the signs leading up to the above-mentioned failure.

[0007] In view of the above circumstances, an object of the present invention is to provide an abnormality diagnosis device that detects an abnormality in a regenerative resistor at an early stage and protects an elevator before a serious failure occurs. [Means for solving the problem]

[0008] An embodiment for achieving the above-mentioned object is an abnormality diagnosis device for a regenerative resistor in an elevator, the device being connected to a power supply circuit of an elevator motor and including a regenerative resistor that is arranged in front of an inverter that supplies power to a motor that drives an elevator and consumes regenerative power from the motor, a switching element that switches current flow to the regenerative resistor, and a free wheel diode that is arranged in parallel with the regenerative resistor, and the device includes a diagnostic current control unit that, when diagnosing the regenerative resistor, supplies a diagnostic current to the switching element to current the regenerative resistor, a current measurement unit that measures the detection value of the current flowing through the regenerative resistor during diagnosis, and a deterioration judgment unit that compares the measured current detection value with a predetermined initial value to judge deterioration of the regenerative resistor and performs abnormality diagnosis according to the degree of deterioration. [Brief description of the drawings]

[0009] [Figure 1] 1 is a block diagram showing a configuration of an abnormality diagnosis system for a regenerative resistor according to an embodiment of the present invention; [Diagram 2] FIG. 1 is an explanatory diagram showing diagnostic patterns (1) to (4) and their characteristics in comparison. [Diagram 3] FIG. 13 is an explanatory diagram showing the diagnostic procedures of diagnostic patterns (1) and (3) together with CS current waveforms. [Figure 4] FIG. 11 is an explanatory diagram showing the diagnostic procedures of diagnostic patterns (2) and (4) together with CS current waveforms. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] <Configuration of the embodiment> Fig. 1 is a block diagram showing the configuration of a regenerative resistor abnormality diagnosis system according to an embodiment of the present invention. The regenerative resistor abnormality diagnosis system shown in Fig. 1 is applied to elevators, escalators, and other lifts, and the following embodiment shows an example in which the system is applied to an elevator.

[0011] As shown in Fig. 1, an elevator car 1 is connected to a counterweight 3 by a main rope 2, and is driven to travel by a hoist motor 4. The hoist motor 4 is inverter-controlled by an inverter INV.

[0012] The inverter INV is composed of power semiconductors such as IGBTs, and receives the converter output voltage supplied between the PN terminals via a smoothing capacitor C. The input converter output voltage is switched at high speed by a gate signal from the elevator (EL) control panel 10 to generate a three-phase AC voltage of the desired voltage and frequency, and controls the hoisting machine motor 4.

[0013] A regenerative resistor PBR and a switching element Q7 connected in series to the regenerative resistor PBR are connected in parallel between the smoothing capacitor C and the inverter INV. The switching element Q7 is made up of a power semiconductor such as an IGBT, and is switched on to cause a regenerative current to flow through the regenerative resistor PBR, consuming the regenerative power generated by the hoisting machine motor 4.

[0014] A freewheeling diode D1 is connected in parallel to the regenerative resistor PBR, and a reverse current blocking diode D2 is connected in parallel to the switching element Q7. The regenerative current flowing through the regenerative resistor PBR is detected by a current detector CS, and this detected current is output to the abnormality diagnosis device 20 as a CS current.

[0015] The abnormality diagnostic device 20 includes a signal changeover switch 21, a CS current measuring section 22, a diagnostic current control section 23, a diagnostic current storage section 24, an initial value storage section 25, and a deterioration determining section .

[0016] The signal changeover switch 21 is normally located on the EL control panel 10 side and outputs a gate signal (Q7 signal) to the switching element Q7. When diagnosing the regenerative resistor PBR, the contacts are switched to output a diagnostic current to the switching element Q7.

[0017] The CS current measuring unit 22 receives the reflux current detected by the current detector CS as the CS current.

[0018] The diagnostic current control unit 23 outputs a gate signal for the switching element Q7 when diagnosing the regenerative resistor PBR.

[0019] The diagnostic current storage unit 24 stores the gate signal of the switching element Q7 as a diagnostic current when diagnosing the regenerative resistor PBR.

[0020] The initial value storage unit 25 stores the CS current value in a normal state as the initial value.

[0021] The deterioration determination unit 26 compares the initial value current waveform with the CS current waveform to determine the deterioration of the CS current, and outputs a protection signal according to the deterioration to the elevator control panel 10. Furthermore, if the deterioration progresses, an abnormality alert is output to the remote monitoring device 30 depending on the degree of deterioration.

[0022] <Operation principle of the embodiment> The internal wire of the PBR regenerative resistor is wound in a coil shape. If the shape of this wire coil is deformed or the filling state of the insulation inside the wire coil changes, the resistance value does not change but the inductance decreases. When the inductance decreases, the time constant L / R decreases. As the time constant L / R decreases, a change occurs in the current waveform, and this is used to diagnose abnormalities.

[0023] As an example, a constant voltage is applied between PN, and a switching element Q7 consisting of a power semiconductor such as an IGBT is switched on to pass a preset constant diagnostic current through the regenerative resistor PBR for a fixed period of time until a steady state is reached. After the steady state is reached, the switching element Q7 is turned off, and the current circulating through the regenerative resistor PBR and the reflux diode (anti-parallel diode) D1 is measured. This reflux current decreases over time, but if the inductance is large, the rate of decrease is slow, and conversely, if the inductance is small, the rate of decrease is fast. For this reason, the reflux current value is measured a fixed period of time after the switching element Q7 is turned off, and if there is a difference of a certain amount compared to the initial value, it is detected as an abnormality, an abnormality alarm is issued, and the elevator is protected.

[0024] <Diagnosis method of the embodiment> When a diagnosis start signal is output from elevator control panel 10, the contacts of signal changeover switch 21 are switched, and the diagnosis current from elevator control panel 10 is output as a gate signal for transistor Q7. Transistor Q7 switches in response to the supply of the diagnosis current, causing a current to flow through regenerative resistor PBR and freewheel diode (anti-parallel diode) D1. Current detector CS detects the freewheel current and supplies it as a CS current to CS current measurement unit 22. CS current measurement unit 22 outputs the detected CS current (freewheel current) to deterioration determination unit 26. Deterioration determination unit 26 compares the waveform of the CS current with the waveform of the initial value current (normal current) stored in initial value storage unit 25, and diagnoses the presence or absence of an abnormality in regenerative resistor PBR and the degree of deterioration.

[0025] The timing for diagnosis can be when the current starts (when the waveform rises) or ends (when the waveform falls).The CS current waveform can be used as the measurement target.

[0026] Furthermore, methods for determining an abnormality based on the difference between the waveforms at the initial time and those at the abnormal time (waveform difference) include a method for determining an abnormality based on the difference in current values ​​after a specified time, as shown in Figure 3, and a method for determining an abnormality based on the time difference until a specified current is reached, as shown in Figure 4.

[0027] By combining the above diagnostic methods, four diagnostic patterns are possible, as shown in Figure 2. Figure 2 also lists the characteristics of each diagnostic pattern (1) to (4).

[0028] FIG. 3 shows diagnostic patterns (1) and (3) determined from the difference in current value after a predetermined time, and FIG. 4 shows diagnostic patterns (2) and (4) determined from the difference in time it takes to reach a predetermined current.

[0029] Diagnostic Pattern (1) The gate signal shown in Fig. 3(a) is applied as a diagnostic current to switching element Q7 for a predetermined time. As shown in Fig. 3(b), when the current starts to flow, the CS current rises and reaches a steady state, and when the current ends, it falls from the steady state.

[0030] As shown in Figure 3(c), during diagnosis, the falling waveforms of the detected value of the CS current flowing through the regenerative resistor PBR and its initial value are compared, and if the difference I1 between the two is greater than or equal to a predetermined current value, the regenerative resistor PBR is diagnosed as being abnormal.

[0031] Diagnostic Pattern (3) As shown in Figure 3(d), during diagnosis, the rising waveforms of the detected current flowing through the regenerative resistor PBR and its initial value are compared, and if the difference I2 between the two is greater than or equal to a predetermined current value, the regenerative resistor PBR is diagnosed as being abnormal.

[0032] Diagnostic Pattern (2) The gate signal shown in Fig. 4(a) is applied as a diagnostic current to switching element Q7 for a predetermined time. As shown in Fig. 4(b), when the current starts to flow, the CS current rises and reaches a steady state, and when the current ends, it falls from the steady state.

[0033] As shown in Figure 4(c), during diagnosis, the falling waveforms of the detected value of the CS current flowing through the regenerative resistor PBR and its initial value are compared, and if the difference T1 in the falling time between the two is greater than a predetermined time, the regenerative resistor PBR is diagnosed as being abnormal.

[0034] Diagnostic Pattern (4) As shown in Figure 4 (d), during diagnosis, the rise waveforms of the detected current value flowing through the regenerative resistor PBR and its initial value are compared, and if the difference T2 between the rise times of the two is greater than or equal to a predetermined time, the regenerative resistor PBR is diagnosed as being abnormal.

[0035] <An example of deterioration judgment> According to an embodiment of the present invention, gradual protection is possible depending on the magnitude of the difference from the initial value. Here, the criteria for gradual protection are as follows, for example. The deterioration determination unit 26 issues an abnormality report to the remote monitoring device 30 depending on the degree of the failure.

[0036] Failure stage 1: Anomaly warning is issued (anomaly warning is issued to the remote monitoring device) Fault stage 2: Regenerative power suppression (Reduce the rated speed to reduce the continuous load on the regenerative resistor and suppress the amount of heat generated. Reduce the acceleration / deceleration to suppress momentary heat generation, etc.) Fault stage 3: Operation stopped (if inter-floor stop, operation will continue to the nearest floor in the powered direction)

[0037] As described above, according to the embodiment of the present invention, it is possible to detect an abnormality in a regenerative resistor at an early stage and protect an elevator before a serious failure occurs. As a result, in an elevator, it is possible to avoid a trapped-in failure caused by damage to the regenerative resistor PBR. Also, in an escalator, it is possible to prevent accidents such as an emergency stop of steps.

[0038] <Example of change> It is also possible to measure the time it takes for the reflux current (CS current) to drop to a specified value and diagnose an abnormality in the regenerative resistor based on the length of that time.

[0039] In addition, diagnosis can also be performed using the waveform of the current flowing through the regenerative resistor PBR when the power is turned on.

[0040] In addition, if there are signs of an abnormality in the regenerative resistor PBR, changing the switching frequency of the switching element Q7 can be expected to change the vibration frequency of the wire of the regenerative resistor PBR and extend its life. In other words, this is a method of changing the ON / OFF threshold of the switching element Q7 to change the hysteresis width, thereby changing the frequency and changing the vibration frequency of the wire.

[0041] Furthermore, diagnostic data may be collected and accumulated, and initial values ​​and abnormal values ​​for each temperature may be compiled into a database in order to improve the accuracy of abnormality diagnosis.

[0042] Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0043] 1...car, 2...main rope, 3...counterweight, 4...hoisting machine motor, 10...EL (elevator) control panel, 20...abnormality diagnosis device, 21...signal changeover switch, 22...CS current measurement unit, 23...diagnosis current control unit, 24...diagnosis current memory unit, 25...initial value memory unit, 26...deterioration determination unit, 30...remote monitoring device, INV...inverter, CS...current measurement device, PBR...regenerative resistor, D1...freewheel diode, Q7...switching element, D2...reverse current blocking diode, C...smoothing capacitor,

Claims

1. a power supply circuit for an elevator motor including a regenerative resistor disposed in front of an inverter that supplies power to a motor that drives an elevator and that consumes regenerative power from the motor, a switching element that switches on and off the power supply to the regenerative resistor, and a free wheel diode disposed in parallel with the regenerative resistor; a diagnostic current control unit that supplies a diagnostic current to the switching element to energize the regenerative resistor when diagnosing the regenerative resistor; a current measuring unit that measures a detected value of a current flowing through the regenerative resistor during diagnosis; An abnormality diagnosis device for a regenerative resistor in an elevator, comprising: a deterioration judgment unit that compares a measured current detection value with a predetermined initial value to judge deterioration of the regenerative resistor and performs abnormality diagnosis according to the degree of deterioration.

2. 2. The regenerative resistor abnormality diagnosis device according to claim 1, wherein during diagnosis, the rising waveforms of the detected current flowing through the regenerative resistor and its initial value are compared, and if the difference between the two is equal to or greater than a predetermined current value, the regenerative resistor is diagnosed as abnormal.

3. 2. The regenerative resistor abnormality diagnosis device according to claim 1, wherein during diagnosis, the falling waveforms of the detected current flowing through the regenerative resistor and its initial value are compared, and if the difference between the two is equal to or greater than a predetermined current value, the regenerative resistor is diagnosed as abnormal.

4. 2. The regenerative resistor abnormality diagnosis device according to claim 1, wherein during diagnosis, the rise waveforms of the detected current value flowing through the regenerative resistor and its initial value are compared, and if the difference in the rise times between the two is greater than a predetermined time, the regenerative resistor is diagnosed as being abnormal.

5. 2. The regenerative resistor abnormality diagnosis device according to claim 1, wherein during diagnosis, the falling waveforms of the current detection value flowing through the regenerative resistor and its initial value are compared, and if the difference in the falling time between the two is greater than a predetermined time, the regenerative resistor is diagnosed as abnormal.

6. The deterioration judgment unit executes at least one of the following processes depending on the abnormality stage of the regenerative resistor: an abnormality sign warning process that issues an abnormality sign warning to a monitoring device, a regenerative power suppression process that reduces the rated speed or acceleration / deceleration to suppress the amount of heat generated, and an operation stop process, or in the case of an elevator, an operation stop process that operates to the nearest floor in the powering direction and then stops operation when stopping between floors.The abnormality diagnosis device for a regenerative resistor described in any one of claims 1 to 5.

7. A diagnostic method implemented by an abnormality diagnostic device connected to a power supply circuit of an elevator motor, the abnormality diagnostic device including: a regenerative resistor that is disposed in front of an inverter that supplies power to a motor that drives an elevator, the regenerative resistor consuming regenerative power from the motor; a switching element that switches on and off current to the regenerative resistor; and a free wheel diode that is disposed in parallel with the regenerative resistor, the abnormality diagnostic device comprising: When diagnosing the regenerative resistor, a diagnostic current is supplied to the switching element to energize the regenerative resistor; During diagnosis, the detected current value flowing through the regenerative resistor is measured, A method for diagnosing an abnormality in a regenerative resistor in an elevator, comprising: comparing a measured current detection value with a preset initial value to determine deterioration of the regenerative resistor; and carrying out an abnormality diagnosis according to the degree of deterioration.

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