JP2007254095A - Elevator device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an elevator having no possibility of adverse affect by electric current detection errors of inverters while suppressing cost. <P>SOLUTION: In two inverter devices IA, IB connected in parallel, first, all of switching elements AX, AY, AZ, BX, BY, BZ of lower arms are turned on while switching elements AU, AV, AW, BU, BV, BW of upper arms are turned off, to form a recirculation loop of an electric current. Next, while the switching element AU is turned on and the switching element AX is turned off for a certain period, an electric current is flowed from a smoothing capacitor 4A to the recirculation loop and then, this state is returned to the original state. An electric current at this time is detected by electric current sensors 11U to 12W, and a ratio of detection values is compared with a ratio of electric current amount estimated by the recirculation loop. Based on the comparison, a correction gain to be given to fetch of electric current signals a to f by a control computing unit 10 is set. Thus, a relative error at least between electric current sensors in each phase is corrected. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an elevator using an AC motor for driving a hoisting machine, and more particularly to an elevator apparatus of a type in which an AC motor is driven by an inverter.

  In recent years, as the height of the building where the elevator is to be installed has increased, the speed of the elevator has increased dramatically, and a speed of 1000 meters per minute has been in the middle of the call. However, a large output motor (electric motor) is required.

  In recent years, the application of AC motors such as induction motors and synchronous motors has also become common for driving hoisting machines. In this case, an inverter is required, so the speedup of the elevator is not only increased motor output. This also leads to an increase in capacity of the inverter. Therefore, as a technique for increasing the capacity of the inverter at this time, there is parallelization of the inverter.

  Here, the paralleling of the inverters refers to a system that uses a plurality of inverters, for example, two inverters, that output less than the required power capacity, and supplies power to the AC motor in parallel with the outputs. The inverter can be used to increase the speed of the elevator, and therefore the cost can be reduced.

  However, in this case, circulating current may be generated between a plurality of inverters in this case. Therefore, it is necessary to consider the suppression. For this reason, in a certain conventional technique, each phase output from the inverter is required. A method has been proposed in which a current is detected by a current detector, the sum of the currents is obtained and suppressed by control (for example, see Patent Document 1).

  Here, in this prior art, the current of each phase of the inverter output is detected by a current detector, the sum of the currents of each phase is obtained, the inverter is controlled based on this, and between the two inverters connected in parallel In this case, generally, the signal output from the current detector is sent to a control arithmetic unit such as a microcomputer via an operational amplifier, a resistor, an A / D converter, and the like. Entered.

  Therefore, if there is an error in these portions, the current detection result also includes an error. And, if there is an error in the current detection result by the current detector in this way, it will not only hinder the suppression of the circulating current, but it will also affect the control of the AC motor that is the load, especially in the elevator It will have an adverse effect.

Therefore, in the conventional technology, high-precision parts with little error are used for parts such as current detectors and operational amplifiers, and correction gains set for capturing current detection results are individually set so that errors are minimized. It was adjusted and corresponded.
JP-A-5-260793

  The prior art described above has a problem in suppressing the product cost because it does not take into account the increase in the number of expensive parts and the complicated adjustment work.

  In the prior art, high-precision parts with little error are used for current detectors, operational amplifiers, and other parts to suppress errors, and the correction gain for capturing current detection results is individually set so that errors are minimized. Adjustments are made manually, but at this time, parts such as high-precision current detectors and operational amplifiers with little error are expensive, and manual adjustment of the correction gain requires skill and troublesome work. .

  In addition, this current detector is necessary for each phase of the inverter. Therefore, when a plurality of inverters are used, the number of current detectors is further increased. For example, in the case of a single inverter, three current detectors are sufficient. However, in the case of two inverters, twice as many as six are required. However, in the above prior art, since there is no consideration for such an increase in current detectors, there is a problem in suppressing the product cost.

  It is an object of the present invention to provide an elevator that does not have an adverse effect associated with an inverter current detection error while reducing costs.

  The above object is achieved in an elevator apparatus of a system in which a motor of a hoisting machine is driven by an inverter device provided with a current detector at each phase output of an inverse conversion unit fed from a DC circuit, the switching element of the inverse conversion unit Is selectively turned on and off to form a first loop path in which the current supplied from the DC circuit to the inverse converter is returned to the switching element and the respective current detectors. Provided is a control calculation means for forming a second loop path in which the DC circuit is disconnected, and the control calculation means detects the current flowing back to the second loop path by the respective current detectors, and This is achieved by calculating and correcting the relative error between the respective current detectors in comparison.

  According to the present invention, the correction gain in capturing the current detection result is automatically set according to the current detection error, so that the product cost is not affected by the number of current detectors, The current can be suppressed, and the deterioration of the ride quality of the elevator can be suppressed.

Embodiment 1
FIG. 1 shows a first embodiment of the present invention, which, as shown in FIG. 1 (a), includes an AC motor 6 for an elevator, and rectifier units 2A and 2B constituting a forward conversion unit of an inverter device. Similarly, variable speed control is performed using two systems of inverter devices IA and IB of the A system and the B system including the inverter units 3A and 3B that constitute the inverse conversion unit and the smoothing capacitors 4A and 4B that constitute the DC circuit. An embodiment in which the present invention is applied to the elevator system described above is shown and is an example of the best mode for carrying out the present invention.

  At this time, the two inverter devices IA and IB are arranged in parallel by the input side reactor 51 and the output side reactor 5, and drive the AC motor 6 in cooperation. Three-phase AC power is supplied from the commercial power source 1 to the rectifier units 2A and 2B via the input side reactor 51, and to the AC motor 6 from the inverter units 3A and 3B via the output side reactor 5. Three-phase AC power is supplied. At this time, the smoothing capacitors 4A and 4B are connected between the rectifier units 2A and 2B and the inverter units 3A and 3B.

  Here, this elevator system is provided with a so-called gearless type hoisting machine, and for this reason, the sheave 7 is directly attached to the rotating shaft of the AC motor 6. A plurality of ropes (one in the figure) are connected to the sheave 7 to connect the car 8 and the counterweight 9 so that the car 8 and the counterweight 9 are connected to the rail. In the state of being guided by the elevator, it is held so as to be movable up and down in the elevator hoistway. As a result, a moving part for performing service by the car 8 across a plurality of floors is configured.

  At this time, first, as shown in FIG. 1B, the inverter unit 3A has three switching elements AU, AV, AW on the upper arm (upper side) and three switching elements AX on the lower arm (lower side). , AY, AZ, and then, the inverter unit 3B has three switching elements BU, BV, BW of the upper arm and switching elements BX, BY, BZ of the lower arm, as shown in FIG. It has. Each of these switching elements is PWM-controlled by the control arithmetic device 10 to operate as a main circuit of a variable voltage variable frequency (VVVF) inverter.

  For this PWM control, current sensors 11U, 11V, 11W, 12U, 12V, and 12W are provided as current detectors on the AC side lines of the inverter units 3A and 3B. A detection encoder 13 is provided, and each detection result is taken into the control arithmetic device 10.

  Here, among the current detectors connected to each output phase of the inverter unit 3A, the current sensor connected to the U phase is 11U, the current sensor connected to the V phase is 11V, and the current sensor is connected to the W phase. Of the current detector connected to each output phase of the inverter unit 3B is 12U, the current sensor connected to the U phase is 12U, the current sensor connected to the V phase is 12V, and the current sensor is connected to the W phase. Is 12 W.

  Moreover, in the following description, the power conversion part comprised by the rectifier part 2A, the smoothing capacitor 4A, and the inverter part 3A, that is, the inverter device IA is referred to as A system, and comprises the rectifier part 2B, the smoothing capacitor 4B, and the inverter part 3B. The power conversion portion, that is, the inverter device IB is referred to as a B system.

  First, the rectifier units 2A and 2B once convert commercial frequency AC power supplied from the commercial power source 1 into direct current, and store it in the smoothing capacitors 4A and 4B to smooth the voltage. Therefore, the smoothing capacitors 4A and 4B form a DC circuit of the inverter device. Next, the inverter units 3 </ b> A and 3 </ b> B convert the DC power of the DC circuit into three-phase AC power with an arbitrary voltage (VV) and an arbitrary frequency (VF), and pass through the output side reactor 5 to the AC motor 6. Supply.

  An operation command is given to the control arithmetic device 10 from an elevator control device (not shown). In response to this, the two inverter devices IA and IB are controlled to control the rotation of the AC motor 6. . Therefore, the AC motor 6 is rotationally driven at a variable speed, and the car 8 is moved up and down together with the counterweight 9, so that necessary elevator operation control is obtained.

  Therefore, the control arithmetic device 10 includes current signals a, b, c, d, e, and f detected by the current sensors 11U, 11V, 11W, 12U, 12V, and 12W, and an encoder 13 that is provided in the AC motor 6. Is used to calculate a control command for the AC motor 6 and outputs a switch command 14 for driving the switching elements of the inverter units 3A and 3B.

  At this time, the current signals a to f (a, b, c, d, e, f) detected by the current sensors 11U, 11V, 11W, 12U, 12V, 12W are input to the control arithmetic unit 10 as they are. Instead, as described above, the amplitude is adjusted to a signal that can be input to the control arithmetic device 10 via an operational amplifier or a resistor (not shown) and input.

  Therefore, at this time, if the accuracy of the current sensor, operational amplifier, resistance, etc. is low and an error is included, the control of the AC motor 6 is affected as described in the prior art, and the elevator ride In addition to deteriorating the comfort, there is a risk that the circulating current between the inverter unit 3A and the inverter unit 3B will increase, causing a decrease in efficiency.

  By the way, this is not a problem because there is a difference in the error of each current detector, but it is a problem that there is a variation (hereinafter referred to as variation) in the error of each current detector. For example, even if there is a current detection error of about 1%, the effect is not so great if it is almost the same in all current detectors. However, when there is a variation in the amount of error between the current detectors, the above-described adverse effect becomes remarkable even if the error amount is 1%.

  Therefore, in the first embodiment, the control arithmetic device 10 includes a correction gain setting unit that sets a correction gain independently for the capture of the current signals a to f by the control arithmetic device 10, and a correction gain that calculates the correction gain. And a current detector arbitrarily selected from among a plurality of current detectors, for example, a current detection value based on the current signal a of the current sensor 11U as a reference, and current signals b to f from other current sensors. The correction gain necessary to make the detected current values equivalently equal to each other is calculated for each current sensor, and the calculated correction gain is set in the correction gain setting section.

  In the correction gain calculation unit, the correction gain can be calculated for each current sensor by executing the process according to the flowchart of FIG. 2, and can be set in the correction gain setting unit. The process shown in the flowchart of FIG. 2 is executed by a program stored in the CPU constituting the control arithmetic device 10. The correction gain calculation process will be described below.

  First, the process of FIG. 2 is executed on the condition that the operation of the elevator system is prohibited, and on the condition that the start of the calculation process is instructed. For this reason, the control arithmetic device 10 is provided with at least one of the external connector 1000, the timer 1001, and the remote control device 1002, and these allow the arithmetic processing to be started before the elevator operation is started, for example, in the early morning. It is instructed to allow the elevator to start operation after the processing is completed.

  At this time, the processing of FIG. 2 may be started at an arbitrary time from an external input device via the external connector 1000, or the processing may be started at an arbitrary time from the remote operation device 1002. On the other hand, the processing of FIG. 2 may be started periodically by the timer 1001.

  Now, it is assumed that the above condition is satisfied and the processing shown in FIG. 2 is started. Then, first, in process step 15, all the switching elements AX, AY, AZ, BX, BY, BZ of the lower arm of each phase of the inverter units 3A, 3B are turned ON. Then, the switching elements of the inverter units 3A and 3B are turned on and off as shown in FIG. 3, and in this case, all the output phases of the inverter units 3A and 3B have the same potential. No current flows.

  In the state of FIG. 3, next, the process proceeds to processing step 16 where the switching element AX of the U-phase lower arm of the A-system inverter unit 3A is turned off and the switching element AU of the U-phase upper arm is turned on. Then, the current I flows back to the current path (referred to as the first loop path) shown in FIG. 4 through the switching element AU turned ON by the charge accumulated in the smoothing capacitor 4A at this time.

 Then, the process proceeds to the next processing step 17, where the switching element AU that has been turned on is turned off, and the switching element AX that has been turned off is turned back on. Then, the smoothing capacitor 4A is disconnected, but since there is an inductance component in the path through which the current I flows at this time, that is, the first loop path, it passes through the switching element AX that is now turned on, Thereafter, the current I continues to flow back to the current path (referred to as the second loop path) shown in FIG.

  The second loop path of FIG. 5 does not include a component that becomes a voltage source element such as the smoothing capacitors 4A and 4B, and is a loop path constituted by a switching element and an output side reactor. It attenuates depending on the time constant due to the resistance and inductance components present in the. Therefore, in the next processing step 18, the current I at this time is detected as current signals a to f by the current sensors 11U to 12W (11U, 11V, 11W, 12U, 12V, 12W).

Then, the current at this time is as shown in FIGS. At this time, the output-side reactor 5 has the same impedance for each phase. Then, time t ₀ is the time when processing step 16 in FIG. 2 is executed, and time t ₁ is the time when processing step 17 is also executed. Here, FIG. 6 shows detection errors of current sensors 11U to 12W. 7 shows a case where there is no variation, and FIG. 7 shows a case where there is a variation in detection error.

First, in FIG. 6, the period from time t ₀ to time t ₁ is a period in which the switching element AU of the U-phase upper arm of the A-system inverter unit 3A is ON and the switching element AX of the lower arm is OFF. Then, the current I increases, and after time t ₁ , it becomes a damped oscillation waveform as shown in the figure.

  At this time, as is clear from the current path of FIG. 5 above, for example, if the value of the current I flowing through the current sensor 11U is Ia, the current value flowing through the current sensor 12U is also Ia, as is apparent from FIG. Moreover, as described above, since the impedance of each phase of the output side reactor 5 is assumed to be equal, the currents of the inverted waveforms whose amplitude is ½ of the current Ia are present in the V phase and the W phase of the inverter unit 3A. Therefore, the current values flowing through the current sensors 11V and 11W and the current sensors 12V and 12W are all Ia / 2.

Therefore, as shown as processing step 18 in FIG. 2, the current signals a to f from the current sensors 11U to 12W are captured at time t _{1 at} this time, and the values of the current signals b to f are changed to the values of the current signal a. By comparing with the value, the detection error for each of the other current signals b to f can be calculated on the basis of the current signal a. For example, when the detection value of the current signal a is Ia, the current signal d If the detection value of Ia is Ia and the detection values of the other current signals b, c, e, and f are Ia / 2, the detection accuracy of the other current sensors varies with reference to the detection accuracy of the current sensor 11U. There will be no.

  However, for example, as shown in FIG. 7, when only the detection value of the current sensor 11W, that is, the detection value by the current signal c is (Ia / 2) K as shown in the figure, there is no detection error. Compared with FIG. 6, the amplitude of the detected current value of the W phase of the A-system inverter unit 3A is K times. In this case, the current sensor 11W is compared to the reference current sensor 11U. Thus, a detection error corresponding to a gain of K times is obtained. FIG. 7 shows a case where the value K of the current sensor 11W is less than 1.

  Therefore, the control arithmetic device 10 executes the processing step 19 after the processing step 18 of FIG. 2, and back-calculates the detected values based on the current signals a to f read as instantaneous values, and captures these current signals a to f. The correction gain to be set to is calculated. However, since the detection accuracy of the current sensor 11U is used as a reference at this time, the correction gain to be set for the capture of the current signal a in the future is 1 (K = 1).

  For example, in the case of FIG. 7, since the output value of the U-phase current sensor 11U of the A-system inverter unit is used as a reference, the current value to flow in the W-phase (U-phase current value Ia × (−½)) In order to compensate for the ratio K times, the correction gain to be set for capturing the current signal c is 1 / K. For other current sensors other than the current sensor 11U, if there is an error, the correction gain is calculated by the same process.

  Thereafter, the correction gain just calculated is set in the correction gain setting unit of the control arithmetic unit 10, whereby the current signals b to f of the current sensors 11 V, 11 W, 12 U, 12 V, and 12 W other than the current sensor 11 U are respectively set. 2 is completed as the correction gain for the capture of the image data. Then, when the processing of FIG. 2 is completed, the prohibition of the elevator operation is lifted, and thereafter, the operation can be arbitrarily started. At this time, for the current sensor having no error, the correction gain is set to 1, that is, K = 1, including the current sensor 11U.

  As a result, when the operation of the elevator is started, variations in detection accuracy are compensated for the current signals a to f of all the current sensors, and are taken into the control arithmetic unit 10 with the same detection accuracy. According to the first embodiment, since the correction gain in capturing the current detection result is automatically set according to the current detection error, an elevator that does not have an adverse effect due to the current detection error of the inverter is provided while suppressing the cost. can do.

  By the way, in the case of this embodiment, the current detection accuracy of each of the current sensors 11V to 12W is converged according to the current detection accuracy of the reference U-phase current sensor 11U. If so, all of the current sensors have the same detection error.

  However, as in the first embodiment, in the case of elevator control, it is not a problem that the detection error of each current sensor is large, but the variation in detection error is a problem as described above. If the detection error is about 1%, the effect will be minimal. In the case of a general current sensor, the detection error is usually suppressed to 1% or less. Therefore, in this embodiment, the control of the AC motor 6 is hindered or the ride comfort of the elevator is increased. There is no risk of adverse effects appearing.

  Here, in the first embodiment, in the processing block 15 of FIG. 2, as shown in FIG. 3, all the switching elements of the lower arms of the inverter units 3A and 3B are turned on. It goes without saying that all of these may be turned on. Further, in the processing block 16 of FIG. 2, the switching element AU of the U-phase upper arm of the A-system inverter unit 3A is turned on, but other switching elements may be used, and a plurality of switching elements are turned on simultaneously. It goes without saying that you can make it.

  At this time, the processing blocks 16 and 17 in FIG. 2 are intended to flow a continuous current temporarily in the loop formed in the inverter units 3A and 3B by the ON / OFF control of the switching elements. Therefore, the method of determining the current return path according to the ON / OFF state of the switching element in the present invention is not limited to that described with reference to FIGS.

  In the first embodiment, the current sensor on the output side of the inverter unit is described. However, as shown in FIG. 14, the present invention uses a PWM forward converter as the rectifier units 2A and 2B. The same correction can be made by applying to a current sensor connected to the input side of the PWM forward converter.

  In this case, as shown in FIG. 15, the rectifier units 2A, 2B by the PWM forward conversion unit are connected in parallel from the power source (commercial power source 1 in FIG. 1) via the input side reactor 51. When the input side reactor 51 is regarded as the output side reactor 5 in the case of the first embodiment shown in FIGS. 3 to 5, the input side reactor 51 is symmetrical to the inverter units 3 </ b> A and 3 </ b> B. Therefore, in this case, it is necessary to provide a process for disconnecting the input-side reactor 51 from the power source side, or a mechanism for disconnecting the input-side reactor 51 (for example, a mechanism such as a disconnector), but the process in the case of the first embodiment described with reference to FIGS. Correction can be performed by the same method as in FIG.

  Next, another embodiment related to the first embodiment will be described. First, FIG. 8 is an embodiment in which the output side reactor 5 in the first embodiment is provided with a short-circuit switch 101. For example, in the embodiment of FIG. 1, when the impedance of the AC motor 6 connected as a load is small, current also flows in the AC motor 6 in the state shown in FIGS. 4 and 5. A difference occurs in the current of the inverter unit 3B, and it becomes difficult to detect and correct the relative error amount of the current sensor.

  Therefore, in this embodiment, a switch 101 is provided as shown in FIG. 8, and the switch 101 is turned on when calculating the correction gain of the current sensor, and the output side reactor 5 is short-circuited so that no current flows to the AC motor 6. As a result, even when the load impedance is small, the correction gain can be calculated without being affected by the influence.

  Here, in FIG. 8, the switch 101 is connected to the output reactor 5 as it is, but at this time, an element that shows a small impedance to the load, such as a resistor or an inductance, may be connected in series to the switch 101. .

  Next, FIG. 9 is an embodiment in which the switch 102 is provided and the AC motor 6 as a load can be disconnected from the output-side reactor 5 in the first embodiment. As in the embodiment, the switch 102 is turned off when calculating the correction gain, so that the AC motor 6 is disconnected from the output-side reactor 5. As a result, even when the load impedance is small, the influence is reduced. The correction gain can be calculated without receiving it.

Embodiment 2
FIG. 10 shows a second embodiment of the present invention. As shown in FIG. 10, this is composed of one AC motor 6 for an elevator, a rectifier unit 20 constituting a forward conversion unit of the inverter device, and an inverse conversion unit. An embodiment in which the present invention is applied to an elevator system in which variable speed control is performed using a single inverter device IC including an inverter unit 21 and a smoothing capacitor 22 constituting a DC circuit is shown. This is also an example of the best mode for carrying out the present invention, and other configurations are the same as those of the first embodiment described with reference to FIG.

  In the second embodiment of FIG. 10, the switching element of the upper arm of the inverter unit 21 is the switching element CU, CV, CW for each phase, and the switching element of the lower arm is the switching element for each phase. CX, CY, CZ. Moreover, about the current sensor installed in each output phase of the inverter unit 21, the current sensor connected to the U phase is 23U, the current sensor connected to the V phase is 23V, and the current sensor connected to the W phase is In this second embodiment, the correction gain can be derived by the same method as in the first embodiment.

  Also in the second embodiment, the control arithmetic device 10 also includes a correction gain setting unit that sets a correction gain independently for taking in the current signals a to f by the control arithmetic device 10 and a correction that calculates the correction gain. A gain calculation unit, and a current detector arbitrarily selected from a plurality of current detectors, for example, a current detection value based on a current signal h of the current sensor 23U, and other current sensors 23V, The correction gain necessary for making the current detection values by the current signals i and j by 23 W equivalently equal is calculated for each current sensor, and the calculated correction gain is set in the correction gain setting unit. It has become.

  In the correction gain calculation unit, the correction gain can be calculated for each current sensor by executing the process according to the flowchart of FIG. 11, and can be set in the correction gain setting unit. At this time, the processing shown in the flowchart of FIG. 11 is also executed by a program stored in the CPU constituting the control arithmetic device 10. The correction gain calculation process will be described below.

  Here, the processing of FIG. 11 is also executed on the condition that the operation of the elevator system is prohibited, and on the condition that the start of the arithmetic processing is instructed. For this reason, although not shown in the figure, the control arithmetic device 10 is provided with an external connector, a timer, a remote control device, and the like. Thus, after the processing is completed, the start of the elevator operation is permitted.

  When the process shown in FIG. 11 is started, in process step 24, as shown in FIG. 12, all the switching elements CX, CY, CZ of the lower arm of each phase of the inverter unit 21 are turned ON. Then, in this case, since all the output phases of the inverter unit 21 have the same potential, no current flows through any of the output phases.

  Next, the process proceeds to processing step 25, and this time, as shown in FIG. 13, the switching element CX of the U-phase lower arm of the inverter unit 21 is turned OFF, and the switching element CU of the U-phase upper arm is turned ON at this time. Due to the electric charge accumulated in 4A, the current I flows through the switching element CU that is turned on to the illustrated path (first loop path).

  Then, the process proceeds to the next processing step 26, and as shown in FIG. 14, the switching element CU that has been turned ON is turned OFF to disconnect the smoothing capacitor 4A, and the switching element CX that has been turned OFF is returned to ON. Thus, the second loop path is formed, and the current I is continuously continued to the second loop path due to the inductance.

  Then, also in this case, the current I attenuates depending on the time constant due to the resistance component and the inductance component existing in the path. Therefore, in the next processing step 27, the current I at this time is detected as the current signals h, i, j by the current sensors 23U, 23V, 23W, and thereafter, in the processing step 27 and the processing step 28, the above-mentioned Similar to processing step 18 and processing step 19 in the processing of FIG. 2 in the first embodiment, the correction gain is calculated, and the calculated correction gain is set in the correction gain setting unit of the control arithmetic device 10, and the processing of FIG. Exit.

  At this time, the current sensor having no error is the same as that of the first embodiment in that the correction gain including the current sensor 23U is set to 1, that is, K = 1, but here, the implementation of FIG. In the case of Form 2, since the current I flows through the AC motor 6, the impedance variation between the phases becomes a problem. However, this variation is hardly a problem when the AC motor 6 is a general squirrel-cage induction motor.

  However, in the case of an electric motor having a saliency in the rotor such as a synchronous motor that has been frequently used in recent years, the inductance value of the motor changes depending on the position of the motor magnetic pole, so the above-mentioned variation cannot be ignored. In this case, as in the case of the first embodiment, the current values of the V-phase and the W-phase do not always have a waveform having an amplitude obtained by multiplying the current value of the U-phase by -1/2.

  Therefore, in the second embodiment, in the processing step 27 of FIG. 11, in addition to the current signals h, i, j, the magnetic pole position detection signal P given from the magnetic pole position detection encoder 13 is fetched, and this magnetic pole position After calculating the inductance value of the AC motor 6 from the signal P, the current value of the remaining phase with respect to the current of the reference phase is calculated on the assumption of the difference in the inductance value.

  At this time, the relationship between the magnetic pole position of the AC motor 6 and the inductance value is a fixed relationship among the individual motors, and therefore can be tabulated in advance. Therefore, in this embodiment, if such a table is used and this is searched by the magnetic pole position signal P, the above-described calculation of the inductance value can be easily obtained.

  Then, when the processing of FIG. 11 is completed, the prohibition of the elevator operation is lifted, and if the operation can be arbitrarily started thereafter, even when the operation of the elevator is started according to the second embodiment, Variations in detection accuracy are compensated for the current signals h, i, j of all the current sensors, and are taken into the control arithmetic unit 10 with the same detection accuracy. The correction gain in the capture is automatically set in accordance with the current detection error, and an elevator that does not have an adverse effect due to the current detection error of the inverter can be provided while suppressing the cost.

  By the way, large and high-speed elevators use large capacity motors. In this case, a motor in which an armature winding is divided into a plurality of windings may be used. In this case, a plurality of inverters are connected to one motor, and power is supplied from another inverter for each winding. For example, in the case of a two-winding motor, there are six terminals with two sets of three-phase windings, and one and the other of the two inverters are respectively connected to the respective windings.

  Therefore, in this case, if the inverter according to the second embodiment is connected to each winding, the correction gain can be derived in exactly the same manner as described above. That is, in this case, since the inductance value of the AC motor 6 can be calculated from the magnetic pole position signal P of one system of motors output from the encoder 13, the method of the second embodiment is applied individually to each inverter. By doing so, a correction gain can be derived.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made without departing from the scope of the present invention.

It is a block diagram which shows Embodiment 1 of the inverter by this invention. It is a flowchart for demonstrating operation | movement of Embodiment 1 of this invention. It is the 1st explanatory view showing the relation between switching control and current of Embodiment 1 of the present invention. It is the 2nd explanatory view showing the relation between switching control and current of Embodiment 1 of the present invention. It is the 3rd explanatory view showing the relation between switching control and current of Embodiment 1 of the present invention. It is explanatory drawing of a current waveform in case there is no error in Embodiment 1 of this invention. It is explanatory drawing of a current waveform when there exists an error in Embodiment 1 of this invention. It is a block diagram at the time of providing the reactor short circuit switch in Embodiment 1 of this invention. It is a block diagram at the time of providing the switch for additional separation in Embodiment 1 of this invention. It is a block diagram which shows Embodiment 2 of the inverter by this invention. It is a flowchart for demonstrating operation | movement of Embodiment 2 of this invention. It is the 1st explanatory view showing the relation between switching control and current of Embodiment 2 of the present invention. It is the 2nd explanatory view showing the relation between switching control and current of Embodiment 2 of the present invention. It is the 3rd explanatory view showing the relation between switching control and current of Embodiment 2 of the present invention. It is a block diagram at the time of applying this invention to a PWM forward conversion part.

Explanation of symbols

IA, IB, IC: Inverter device 1: Commercial power supply 2A, 2B, 20: Rectifier part (forward conversion part)
3A, 3B, 21: Inverter part (inverse conversion part)
4A, 4B, 22: Smoothing capacitor 5: Reactor on output side 51: Reactor on input side 6: AC motor 7: Shear wheel 8: Car cage 9: Counterweight
10: Control arithmetic unit 11U: A system U phase current sensor 11V: A system V phase current sensor 11W: A system W phase current sensor 12U: B system U phase current sensor 12V: B system V phase current sensor 12W: B system W phase current sensor 13: Encoder 14: Switch command 23U: U phase current sensor 23V: V phase current sensor 23W: W phase current sensor 101: Switch (switch for reactor short circuit)
102: Switch (switch for load separation)
1000: External connector 1001: Timer 1002: Remote operation

Claims (9)

In an elevator apparatus of a system in which a motor of a hoisting machine is driven by an inverter apparatus provided with a current detector at each phase output of an inverse conversion unit fed from a DC circuit,
The switching element of the inverse conversion unit is selectively ON / OFF controlled to form a first loop path through which the current supplied from the DC circuit to the inverse conversion unit is returned to the switching element and the respective current detectors. Then, a control calculation means for forming a second loop path in which the DC circuit is separated from the loop path is provided,
The control calculation means detects the current flowing back to the second loop path by the respective current detectors, compares them with each other, calculates a relative error between the respective current detectors, and corrects it. It is comprised so that an elevator apparatus characterized by the above-mentioned. The elevator apparatus according to claim 1,
The first loop path includes ON control of only one switching element in the upper arm of the inverse conversion unit, and ON control of switching elements other than the switching element of the lower arm paired with the upper arm. Formed by
The elevator apparatus according to claim 2, wherein the second loop path is formed by OFF control of all switching elements of the upper arm of the inverse conversion unit and ON control of all switching elements of the lower arm. The elevator apparatus according to claim 1,
Calculation of a relative error between the respective current detectors by the control calculation means,
Based on any one of the current detectors as a reference, the current value detected by the current detector is determined by the ON / OFF state of the switching element of the inverse conversion unit to the current value detected by another current detector. An elevator apparatus characterized by being given in comparison with a value multiplied by a ratio. The elevator apparatus according to claim 1,
The motor includes an encoder for detecting a magnetic pole position;
The elevator apparatus according to claim 1, wherein the control calculation means is configured such that a correction based on a magnetic pole position signal detected by the encoder is given to the calculation of a relative error between the current detectors. The elevator apparatus according to claim 1,
The said inverter apparatus is comprised by the two reverse conversion parts connected in parallel by the output side reactor, The elevator apparatus characterized by the above-mentioned. The elevator apparatus according to claim 5,
The output side reactor is provided with the switch means which detours the said reactor, The elevator apparatus characterized by the above-mentioned. The elevator apparatus according to claim 5,
The elevator apparatus, wherein the output side reactor of the motor of the hoisting machine includes switch means for separating the motor of the hoisting machine from the reactor. The elevator apparatus according to claim 1,
The elevator apparatus characterized in that the processing by the control calculation means is periodically started by a timer at least on one side and at any time by remote operation on the other side. The elevator apparatus according to claim 1,
An elevator apparatus characterized in that the motor of the hoisting machine is a multi-winding motor, and an inverter device is provided independently for each of the plurality of windings of the motor.

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