JP2012060748A - Magnetic flux waveform calculation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To calculate the magnetic flux waveform of each stator winding without leading a neutral point potential to the outside.SOLUTION: A magnetic flux waveform calculation device includes a voltage detection unit 2 which detects a line voltage generated between three phase windings when, while AC drive voltages to three phase windings of a motor 51 having stator windings composed of Y-connected three phase windings are not supplied, a rotor 54 of the motor 51 is rotated and also A/D converts the line voltage to output it as voltage data D1s, D2s, and D3s, and a processing unit 3 which executes in order a Δ-Y conversion process which, upon accepting the voltage data D1s, D2s, and D3s as its input, Δ-Y converts them to calculate phase voltage data Du1, Du2, and Du3 indicating phase voltages with regard to the phase windings and a magnetic flux waveform calculation process which integrates the calculated phase voltage data Du1, Du2, and Du3 to calculate the waveform data of each phase winding Dsu, Dsv, and Dsw.

Description

  The present invention relates to a magnetic flux waveform calculating apparatus for measuring a magnetic flux waveform of a winding during a motor characteristic test.

  As a motor characteristic test apparatus, a PM motor characteristic test apparatus disclosed in Patent Document 1 below is known. In this characteristic test apparatus, a PM motor, which is a device under test, is directly connected to a test motor to rotate the rotor, or the PM motor is driven by another drive source, and control from the drive source is performed after the drive. The rotor is cut off and the rotor is set in a free-run state, and the induced voltage induced in the stator winding in the rotating state of the rotor is detected by the voltage detector, and the waveform of the induced voltage is passed through the A / D converter. Is converted to digital data (waveform data), and then this waveform data is recorded on a personal computer. Patent Document 1 below describes an example of creating a motor characteristic diagram showing the relationship between the rotational speed of the rotor and the induced voltage based on the recorded waveform data. In the test, as other motor characteristics, a magnetic flux waveform of the stator winding is calculated based on the waveform data and displayed on a display device or the like.

JP 2002-267727 A (page 2-3, FIGS. 1 and 6)

  However, the motor characteristic test apparatus has the following problems to be solved. That is, as shown in FIG. 6, three phase windings 52u, 52v, 52w (U phase winding, V phase winding, W phase winding) Y-connected as the stator winding 52 are provided. Each of the three-phase motors 51 configured to rotate by supplying a three-phase AC voltage (AC drive voltage) to voltage input terminals U, V, and W connected to ends of the lines 52u, 52v, and 52w. The above-described magnetic flux waveforms of the phase windings 52u, 52v, 52w are calculated by integrating the waveforms of the induced voltages U1, U2, U3 generated at both ends of the phase windings 52u, 52v, 52w, that is, the phase voltage waveforms. Is done. For this reason, in the motor characteristic test apparatus, the potential of the neutral point A of the phase windings 52u, 52v, and 52w is pulled out by the wiring 53 to the outside of the motor 51, and the phase winding is based on the potential of the neutral point A. The induced voltages U1, U2, U3 generated at both ends of the lines 52u, 52v, 52w are measured.

  However, in general motors, there are few structures that can easily extract the neutral point potential to the outside in the state of the finished product, and even if the neutral point potential can be extracted, the work required to pull it out The time will be longer. For this reason, the above-described motor characteristic test apparatus has a problem to be solved that it may be difficult to perform a motor characteristic test.

  The present invention has been made to solve the above-described problems, and mainly provides a magnetic flux waveform calculation device capable of calculating the magnetic flux waveform of each stator winding without drawing the potential at the neutral point to the outside. Objective.

  In order to achieve the above object, a magnetic flux waveform calculating apparatus according to claim 1 is characterized in that at least one of the three phase windings of a motor having a stator winding composed of three phase windings that are Y-connected. A magnetic flux waveform calculating device for calculating a magnetic flux waveform of a phase winding, wherein the three phase windings are rotated when a rotor of the motor is rotated in a state where an AC drive voltage is not supplied to the three phase windings. A voltage detecting unit that detects a line voltage generated between the lines, A / D converts the line voltage and outputs the line voltage data, and inputs the line voltage data and performs Δ-Y conversion; Δ-Y conversion processing for calculating phase voltage data indicating a phase voltage for the at least one phase winding, and integration of the calculated phase voltage data to calculate the magnetic flux waveform data of the at least one phase winding. The magnetic flux waveform calculation process And a processing unit that executes in this order.

  Moreover, the magnetic flux waveform calculation device according to claim 2 is the magnetic flux waveform calculation device according to claim 1, wherein the processing unit performs Fourier transform on the input line voltage data and obtains each of the obtained Fourier transforms. The DC-removing process for removing the DC component from the frequency components and performing inverse Fourier transform on each frequency component from which the DC component has been removed to generate new line voltage data is the Δ−Y. Prior to the conversion process, the Δ-Y conversion process is executed on the new line voltage data.

  The magnetic flux waveform calculation device according to claim 3 is the magnetic flux waveform calculation device according to claim 1 or 2, wherein the processing unit is configured to generate the magnetic flux of the at least one phase winding based on the calculated magnetic flux waveform data. Display processing for displaying the waveform on the display unit is executed.

  According to the magnetic flux waveform calculation apparatus of claim 1, each of the voltage windings using only the voltage input terminals connectable from the outside without drawing out the potential of the neutral point of the phase winding constituting the motor to the outside of the motor. The magnetic flux waveform of the phase winding can be calculated (measured). Therefore, the magnetic flux waveform of each phase winding can be calculated even for a motor that cannot extract the neutral potential to the outside.

  According to the magnetic flux waveform calculating apparatus of the second aspect, even when a direct current component is added to the line voltage data, the processing unit executes the direct current removal process, and the direct current included in the line voltage data. Remove ingredients. Therefore, according to this magnetic flux waveform calculation device, it is possible to reliably avoid a situation in which the magnetic flux waveform data that is an integral value diverges due to the DC component due to the integration (sequential addition) performed in the magnetic flux waveform calculation processing. Therefore, an accurate magnetic flux waveform of the phase winding can be calculated based on accurate magnetic flux waveform data.

  According to the magnetic flux waveform calculating apparatus of claim 3, the processing unit executes display processing, and displays the magnetic flux waveform on the display unit based on the calculated magnetic flux waveform data. )can do.

1 is a configuration diagram of a magnetic flux waveform calculation device 1. FIG. 4 is a configuration diagram of a motor 51 for explaining a configuration of a stator winding 52. FIG. 4 is a waveform diagram of line voltages U1s, U2s, U3s of the stator winding 52. FIG. 6 is a waveform diagram of phase voltages U1, U2, U3 of the stator winding 52. FIG. It is a wave form diagram which shows each magnetic flux waveform Su, Sv, Sw of phase winding 52u, 52v, 52w. FIG. 5 is an explanatory diagram for explaining a configuration in which each phase voltage U1, U2, U3 is measured by drawing the potential of a neutral point A to the outside of a motor 51.

  Hereinafter, an embodiment of a magnetic flux waveform calculating apparatus 1 will be described with reference to the accompanying drawings.

  First, the configuration of the motor 51 to be tested by the magnetic flux waveform calculating apparatus 1 will be described with reference to FIGS. The motor 51 includes a stator winding 52 having three phase windings 52u, 52v, 52w (U-phase winding, V-phase winding, W-phase winding) Y-connected, a rotor 54, and each phase. Three-phase AC voltage (AC drive voltage) for driving each phase winding 52u, 52v, 52w connected to each end of windings 52u, 52v, 52w (end on the side different from neutral point A) Voltage input terminals U, V, and W (terminals that can be connected (accessed) from the outside of the motor 51).

  Next, the configuration of the magnetic flux waveform calculation device 1 will be described with reference to the drawings.

  As shown in FIG. 1, the magnetic flux waveform calculation device 1 includes, as an example, a voltage detection unit 2, a processing unit 3, a storage unit 4, and a display unit 5, and each phase winding constituting the stator winding 52 of the motor 51. The magnetic flux waveforms Su, Sv, Sw (see FIG. 5) of the lines 52u, 52v, 52w (see FIG. 2) are calculated and displayed.

  As shown in FIG. 2, the voltage detection unit 2 performs A / D conversion on a voltage signal input between a pair of input terminals, and outputs it as voltage data indicating the amplitude of the voltage signal. Circuits 2a, 2b and 2c are provided. In this case, each of the A / D conversion circuits 2a, 2b, and 2c is configured to include an amplifier and an A / D converter (both not shown) as an example, and between each input terminal in synchronization with a common sampling clock. The voltage data is output by sampling the voltage signal input to. In this example, as will be described later, a pair of input terminals of one A / D conversion circuit 2a is connected to voltage input terminals U and V of the motor 51, and a pair of other A / D conversion circuits 2b is connected. The input terminals are connected to the voltage input terminals V and W of the motor 51, and the pair of input terminals of the remaining one A / D conversion circuit 2 c are connected to the voltage input terminals W and U of the motor 51.

  Therefore, the A / D conversion circuit 2a connected to the voltage input terminals U and V performs A / D conversion on the line voltage U1s shown in FIG. 2 and outputs it as voltage data (line voltage data) D1s. The A / D conversion circuit 2b connected to the voltage input terminals V and W performs A / D conversion on the line voltage U2s shown in FIG. 2 and outputs it as voltage data (line voltage data) D2s. The A / D conversion circuit 2c connected to the voltage input terminals W and U performs A / D conversion on the line voltage U3s shown in FIG. 2 and outputs it as voltage data (line voltage data) D3s.

  The processing unit 3 includes a CPU as an example, operates according to an operation program stored in the storage unit 4, and inputs each voltage data D1s, D2s, D3s output from the voltage detection unit 2. And stored in the storage unit 4. Further, the processing unit 3 executes a direct current removal process, a Δ-Y conversion process, a magnetic flux waveform calculation process, and a display process.

  The storage unit 4 is configured by a hard disk device or a semiconductor memory, and stores the above-described operation program for the processing unit 3 in advance. The storage unit 4 is used as a work memory by the processing unit 3 and stores voltage data D1s, D2s, D3s, and the like.

  As an example in this example, the display unit 5 is configured using a display device such as a liquid crystal display device as one component of the magnetic flux waveform calculation device 1. The display unit 5 displays the magnetic flux waveforms Su, Sv, Sw calculated by the processing unit 3 on the screen. The magnetic flux waveforms Su, Sv, and Sw need only be displayed in a state that the user of the magnetic flux waveform calculation device 1 can see, and therefore, the display unit 5 is replaced with a plotter device or a printer device instead of the display device. Can also be configured.

  Next, the operation of the magnetic flux waveform calculation device 1 will be described with reference to the drawings. It is assumed that the voltage input terminals U, V, W of the motor 51 and the A / D conversion circuits 2a, 2b, 2c of the voltage detector 2 are connected in advance with the above correspondence.

  In the state where the AC drive voltage is not supplied, for example, the output shaft 55 directly connected to the rotor 54 is driven by a drive motor (not shown), so that the rotor 54 is rotated at a constant rotational speed. A phase voltage U1 (voltage indicated by a very thick line in FIG. 4) is generated in the phase winding 52u constituting the stator winding 52 of the motor 51, and a phase voltage U2 (indicated by a thick line in FIG. 4) is generated in the phase winding 52v. Voltage) is generated, and a phase voltage U3 (voltage indicated by a thin line in FIG. 4) is generated in the phase winding 52w. As a result, a line voltage U1s (voltage indicated by a thick line in FIG. 3) is generated between the voltage input terminals U and V of the motor 51, and a line voltage U2s (FIG. 3) is generated between the voltage input terminals V and W. 3 is generated between the voltage input terminals W and U, and a line voltage U3s (a voltage indicated by a thin line in FIG. 3) is generated.

  In this state, in the magnetic flux waveform calculation device 1, each A / D conversion circuit 2a, 2b, 2c of the voltage detection unit 2 inputs the line voltages U1s, U2s, U3s and performs A / D conversion to obtain a voltage. Data (line voltage data) D1s, D2s, and D3s are output. The processing unit 3 inputs the voltage data (line voltage data) D1s, D2s, D3s for at least one cycle of the line voltage U1s and stores the data in the storage unit 4.

  Next, the processing unit 3 executes a direct current removal process. In this direct current removal process, the processing unit 3 first performs a Fourier transform on each of the voltage data D1s, D2s, and D3s, and at the same time, outputs a direct current from the frequency components of the voltage data D1s, D2s, and D3s obtained by the Fourier transform. Each component (0th order component) is removed. Next, the processing unit 3 performs inverse Fourier transform on each frequency component of the voltage data D1s, D2s, and D3s from which the DC component has been removed to generate new voltage data D1s, D2s, and D3s. This completes the direct current removal process.

Subsequently, the processing unit 3 executes Δ-Y conversion processing. In this Δ-Y conversion process, the processing unit 3 uses the same time data of the new voltage data D1s, D2s, D3s (data sampled at the same timing in the A / D conversion circuits 2a, 2b, 2c) as follows. Are converted into phase voltage data Du1, Du2, and Du3 representing the phase voltages U1, U2, and U3 shown in FIG. 4 and stored, using the Δ-Y conversion arithmetic expressions (1), (2), and (3). Store in part 4.
Du1 = (D1s−D3s) / 3 (1)
Du2 = (D2s−D1s) / 3 (2)
Du3 = (D3s−D2s) / 3 (3)

  Next, the processing unit 3 executes a magnetic flux waveform calculation process. In this magnetic flux waveform calculation process, the processing unit 3 integrates (sequentially adds) the phase voltage data Du1 stored in the storage unit 4 to generate a magnetic flux waveform Su generated in the phase winding 52u (see FIG. 5). The indicated waveform data (magnetic flux waveform data) Dsu is calculated and stored in the storage unit 4. Similarly, the processing unit 3 uses the waveform data (magnetic flux waveform data) Dsv indicating the magnetic flux waveform Sv (see FIG. 5) generated in the phase winding 52v and the magnetic flux waveform Sw (see FIG. 5) generated in the phase winding 52w. Waveform data (magnetic flux waveform data) Dsw is calculated and stored in the storage unit 4.

  Finally, the processing unit 3 executes display processing. In this display process, the processing unit 3 reads the waveform data Dsu, Dsv, Dsw stored in the storage unit 4, and displays the magnetic flux waveforms Su, Sv, Sw represented by the waveform data Dsu, Dsv, Dsw. 5 is displayed as shown in FIG. In FIG. 5, the magnetic flux waveform Su is represented by a very thick line, the magnetic flux waveform Sv is represented by a thick line, and the magnetic flux waveform Sw is represented by a thin line.

  As described above, according to the magnetic flux waveform calculating apparatus 1, the voltage that can be connected from the outside without extracting the potential of the neutral point A of the phase windings 52 u, 52 v, 52 w constituting the motor 51 to the outside of the motor 51. Using only the input terminals U, V, W, the magnetic flux waveforms Su, Sv, Sw of the phase windings 52u, 52v, 52w can be calculated (measured). Therefore, the magnetic flux waveforms Su, Sv, Sw of the phase windings 52u, 52v, 52w can be calculated even for a motor that cannot extract the potential of the neutral point A to the outside.

  Further, in this magnetic flux waveform calculating apparatus 1, for example, in the voltage detection unit 2, even when a DC component is added to each voltage data D1s, D2s, D3s, the processing unit 3 executes a DC removal process, and each voltage data This DC component included in D1s, D2s, and D3s is removed. Therefore, according to the magnetic flux waveform calculating apparatus 1, it is possible to reliably prevent the waveform data Dsu, Dsv, Dsw that are integrated values from divergence due to the DC component by integration (sequential addition) performed in the magnetic flux waveform calculation processing. Therefore, accurate waveform data Dsu, Dsv, Dsw can be calculated. As a result, the accurate magnetic flux waveform Su of the phase windings 52u, 52v, 52w is based on the waveform data Dsu, Dsv, Dsw. , Sv, Sw can be calculated.

  Further, according to the magnetic flux waveform calculation device 1, the processing unit 3 executes display processing, and displays the magnetic flux waveforms Su, Sv, Sw on the display unit 5 based on the calculated magnetic flux waveform data Dsu, Dsv, Dsw. Therefore, the magnetic flux waveforms Su, Sv, Sw can be measured (confirmed) visually. In addition, in the magnetic flux waveform calculation device 1 described above, the display unit 5 is included as one component of the magnetic flux waveform calculation device 1, but it is not illustrated in place of the configuration having the display unit 5 as a component. It is also possible to configure the magnetic flux waveform calculating device in such a configuration that the display unit 5 can be connected as an external device. In the magnetic flux waveform calculating apparatus having this configuration, the processing unit 3 performs, as a display process, each magnetic flux waveform data via the transmission path with respect to a display unit connected as an external device via the transmission path (not shown). Dsu, Dsv, and Dsw are output. On the other hand, the display unit connected to the magnetic flux waveform calculation device as an external device inputs the magnetic flux waveform data Dsu, Dsv, Dsw, and based on the magnetic flux waveform data Dsu, Dsv, Dsw, the magnetic flux waveforms Su, Sv, Sw. Is displayed on the screen.

  In the magnetic flux waveform calculation device 1 described above, the processing unit 3 performs a direct current removal process, thereby adopting a configuration that prevents the divergence of the waveform data Dsu, Dsv, and Dsw due to the direct current component. If there is no possibility of superimposing DC components, a configuration in which DC removal processing is omitted can be adopted. Further, the above-described magnetic flux waveform calculation device 1 employs a configuration in which the magnetic flux waveforms Su, Sv, Sw of all the phase windings 52u, 52v, 52w are calculated and displayed on the display unit 5. A configuration in which one or two magnetic flux waveforms selected in advance from the lines 52u, 52v, and 52w are calculated and displayed on the display unit 5 may be employed.

DESCRIPTION OF SYMBOLS 1 Magnetic flux waveform calculation apparatus 2 Voltage detection part 3 Processing part 5 Display part 51 Motor 52 Stator winding 52u, 52v, 52w Phase winding 54 Rotor D1s, D2s, D3s Voltage data Su, Sv, Sw Magnetic flux waveform U1, U2, U3 phase voltage U1s, U2s, U3s correlation voltage

Claims (3)

A magnetic flux waveform calculating device for calculating a magnetic flux waveform of at least one phase winding of the three phase windings of a motor having a stator winding composed of three phase windings connected in Y-direction,
The line voltage generated between the three phase windings when the rotor of the motor is rotated in a state where the AC drive voltage is not supplied to the three phase windings is detected and the line voltage is set to A A voltage detection unit that performs / D conversion and outputs as line voltage data;
The line voltage data is input and Δ-Y converted to calculate phase voltage data indicating the phase voltage of the at least one phase winding, and the calculated phase voltage data is integrated. And a processing unit that executes a magnetic flux waveform calculation process for calculating the magnetic flux waveform data of the at least one phase winding in this order.   The processing unit performs a Fourier transform on the input line voltage data, removes a DC component from each frequency component obtained by the Fourier transform, and applies the frequency component from which the DC component has been removed. A DC removal process for performing inverse Fourier transform to generate new line voltage data is performed prior to the Δ-Y conversion process, and then the Δ-Y is applied to the new line voltage data. The magnetic flux waveform calculation apparatus according to claim 1, wherein the conversion process is executed.   3. The magnetic flux waveform calculation device according to claim 1, wherein the processing unit executes display processing for displaying the magnetic flux waveform of the at least one phase winding on a display unit based on the calculated magnetic flux waveform data.

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