JP2006162309A - Current detection device and motor control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a current detection device capable of reducing its size and weight, and that has high accuracy. <P>SOLUTION: Currents in a U-phase bus bar 2a to a W-phase bus bar 2c are detected by a U-phase current detector 4a to a W-phase current detector 4c inclusive, and dispersion of each characteristic or the like is compensated by a current compensation part 20, to thereby determine detector output currents isnsu to isnsw. Prescribed operation is performed, based on the detector output currents by a non-interferential filtering part 21, and the influence of currents in other phases in the detector output currents is removed, to thereby determine currents iu, iv, iw in each phase; and the output from a three-phase inverter 11 is controlled through a current control part 22 so as to acquire a current instruction value ir, and a motor 12 is controlled. Since the dispersion of detection characteristics of the U-phase current detector 4a to the W-phase current detector 4c inclusive are compensated and the current in each phase is determined by the non-interferential filtering part 21, the influence of the current of a phase other than the detecting object is reduced without using a magnetic core, and detection accuracy is improved. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a current detection device and a motor control device, and in particular, a current detection device that can be reduced in size and weight and can reduce a current detection error due to the influence of a current other than a current to be measured. The present invention relates to an electric motor control device capable of high control.

  As a current detector in a conventional AC motor control device, a U-shaped iron core divided into two parts, a Hall element inserted so as to be sandwiched between the divided parts of the iron core, and a control for attaching the Hall element Some of the U-shaped iron cores are provided with a substrate and a sensor housing that integrates them, and a U-shaped recess is formed along the surface. And it is easy to insert and assemble a bus bar in a U-shaped concave part, and there is a thing which can attach a current sensor after assemble | attaching a bus bar (for example, refer patent document 1).

JP 2002-189039 (paragraph numbers 0010 and 0012 and FIG. 1)

  The conventional current sensor is configured as described above, has a U-shaped iron core, and is assembled by inserting a bus bar into a U-shaped recess formed along the surface portion. Therefore, an iron core that is large enough to insert the bus bar into the recess is required. For this reason, for example, when incorporated in a three-phase inverter, there is a problem in miniaturization and high-density mounting. Moreover, the structure combining the conductor and the iron core complicates the assembly process of the three-phase inverter, leading to an increase in the number of assembling steps, and causes an increase in cost. The present invention has been made to solve the above-described problems, and can be reduced in size and weight, and a current detection device that can reduce a current detection error due to the influence of a current other than the current to be measured, and It is an object of the present invention to obtain an electric motor control device capable of reducing current detection errors and performing highly accurate control.

The current detection device according to the present invention includes:
A plurality of current detectors having a magnetic flux detection element, and a current calculation means,
One of the current detectors is disposed in the vicinity of the detection target conductor through which the detection target current to be detected flows, and other than the current detector, the non-detection conduction through which the non-detection current that is not the detection target flows. One of the current detectors is arranged near the body, and generates a detection target electric signal according to a magnetic flux generated by a detection target current and a non-detection target current and interlinked with its own magnetic flux detection element. The other of them generates a non-detection target electric signal according to the magnetic flux that is generated by the detection target current and the non-detection target current and interlinks with its own magnetic flux detection element,
The current calculation means compensates for the detection target and non-detection target electrical signals in order to compensate for variations in the current-to-electrical signal conversion characteristics of each current detector, and based on the compensated detection target and non-detection target electrical signals. The current to be detected is obtained.

And the electric motor control device concerning this invention is
It has a three-phase inverter device, a current detection device, and a switching control device,
The three-phase inverter device has an open / close element, converts DC power to AC power, and supplies it to the motor.
A current detection device is a current detection device according to any one of claims 1 to 4, and detects a current on an AC side of a three-phase inverter device,
The open / close control device controls the electric motor by performing open / close control of the open / close element based on the alternating current detected by the current detection device.

Furthermore, the electric motor control device according to the present invention includes:
It has a three-phase inverter device, a current detection coordinate conversion device, and a switching control device,
The three-phase inverter device has an open / close element, converts DC power to AC power, and supplies it to the motor via a three-phase conductor.
The current detection coordinate conversion device includes a current detector having a magnetic flux detection element, and current calculation coordinate conversion means,
Each current detector is arranged in the vicinity of the conductor of the detection target phase, and generates an electric signal according to the magnetic flux generated by the current of the detection target phase and the current of the non-detection phase and interlinked with its own magnetic flux detection element. And
The current calculation coordinate conversion means performs a current-to-electric signal conversion compensation calculation by multiplying each electric signal by a predetermined compensation coefficient in order to compensate for variations in the current-to-electric signal conversion characteristics of each current detector. A current of each phase is obtained by performing a predetermined non-interference calculation based on each electric signal subjected to the signal conversion compensation calculation, and d on the rotation orthogonal coordinate synchronized with the magnetic flux vector of the motor from the current of each phase. A three-phase / two-phase coordinate calculation for obtaining an axial current and a q-axis current, and a non-interference calculation and a three-phase / two-phase coordinate calculation are performed together.
The opening / closing control device controls the electric motor by controlling opening / closing of the opening / closing element based on the d-axis current and the q-axis current.

According to the current detection device of the present invention,
A plurality of current detectors having a magnetic flux detection element, and a current calculation means,
One of the current detectors is disposed in the vicinity of the detection target conductor through which the detection target current to be detected flows, and other than the current detector, the non-detection conduction through which the non-detection current that is not the detection target flows. One of the current detectors is arranged near the body, and generates a detection target electric signal according to a magnetic flux generated by a detection target current and a non-detection target current and interlinked with its own magnetic flux detection element. The other of them generates a non-detection target electric signal according to the magnetic flux that is generated by the detection target current and the non-detection target current and interlinks with its own magnetic flux detection element,
The current calculation means compensates for the detection target and non-detection target electrical signals in order to compensate for variations in the current-to-electrical signal conversion characteristics of each current detector, and based on the compensated detection target and non-detection target electrical signals. Since the current to be detected is obtained,
Dispersion of current-to-voltage conversion characteristics for each current detector can be compensated, and the current component outside the detection target mixed in the detection target electrical signal that is the current detection result of the current detector is removed to obtain the detection target current. For this reason, it is possible to accurately detect the current without suppressing a decrease in the current detection accuracy without providing a magnetic core for collecting the magnetic current.

And according to the motor control device according to the present invention,
It has a three-phase inverter device, a current detection device, and a switching control device,
The three-phase inverter device has an open / close element, converts DC power to AC power, and supplies it to the motor.
A current detection device is a current detection device according to any one of claims 1 to 4, and detects a current on an AC side of a three-phase inverter device,
Since the open / close control device controls the electric motor by controlling the open / close element based on the alternating current detected by the current detection device,
Dispersion of current-to-voltage conversion characteristics for each current detector can be compensated, and the current component outside the detection target mixed in the detection target electrical signal that is the current detection result of the current detector is removed to obtain the detection target current. Therefore, even if a magnetic core for collecting magnets is not provided, it is possible to accurately detect a current while suppressing a decrease in current detection accuracy, and it is possible to accurately control an electric motor using the detected current.

Furthermore, according to the motor control device of the present invention,
It has a three-phase inverter device, a current detection coordinate conversion device, and a switching control device,
The three-phase inverter device has an open / close element, converts DC power to AC power, and supplies it to the motor via a three-phase conductor.
The current detection coordinate conversion device includes a current detector having a magnetic flux detection element, and current calculation coordinate conversion means,
Each current detector is arranged in the vicinity of the conductor of the detection target phase, and generates an electric signal according to the magnetic flux generated by the current of the detection target phase and the current of the non-detection phase and interlinked with its own magnetic flux detection element. And
The current calculation coordinate conversion means performs a current-to-electric signal conversion compensation calculation by multiplying each electric signal by a predetermined compensation coefficient in order to compensate for variations in the current-to-electric signal conversion characteristics of each current detector. A current of each phase is obtained by performing a predetermined non-interference calculation based on each electric signal subjected to the signal conversion compensation calculation, and d on the rotation orthogonal coordinate synchronized with the magnetic flux vector of the motor from the current of each phase. A three-phase / two-phase coordinate calculation for obtaining an axial current and a q-axis current, and a non-interference calculation and a three-phase / two-phase coordinate calculation are performed together.
Since the open / close control device controls the electric motor by controlling the open / close element based on the d-axis current and the q-axis current,
Dispersion of current-to-voltage conversion characteristics for each current detector can be compensated, and the current component outside the detection target mixed in the detection target electrical signal that is the current detection result of the current detector is removed to obtain the detection target current. Therefore, even if a magnetic core for collecting magnets is not provided, it is possible to accurately detect a current while suppressing a decrease in current detection accuracy, and it is possible to accurately control an electric motor using the detected current. In addition, since the non-interference calculation and the three-phase / two-phase coordinate calculation are performed together, the number of calculations can be reduced, and the control accuracy can be improved by increasing the calculation speed.

Embodiment 1 FIG.
1 to 4 show a first embodiment for carrying out the present invention. FIG. 1 is a configuration diagram showing a configuration of an electric motor control device using a current detection device, and FIG. FIG. 3 is a side view showing the positional relationship between the U-phase bus bar and each phase current detector, and FIG. It is a schematic diagram which shows what is linked to the current detection element of a U-phase current detector among the magnetic fluxes generated by the phase current, V-phase current, and W-phase current. In FIG. 1, the motor control device 10 includes a control arithmetic device 1 and a three-phase inverter 11. DC power is supplied from the DC power source 9 and is converted into three-phase AC of variable voltage and variable frequency in the three-phase inverter 11, via the U-phase cable 3 a, V-phase cable 3 b, and W-phase cable 3 c that are three-phase wiring. The electric motor 12 is supplied.

  Three-phase inverter 11 includes U-phase arm 15a, V-phase arm 15b, W-phase arm 15c, U-phase bus bar 2a, V-phase bus bar 2b, W-phase bus bar 2c, U-phase bus bar 2a, V-phase bus bar 2b, W It has a U-phase current detector 4a, a V-phase current detector 4b, and a W-phase current detector 4c for detecting the current of the phase bus bar 2c. The control arithmetic device 1 includes a current compensation unit 20, a non-interacting filtering unit 21, a current control unit 22, and a PWM signal generation unit 23. A rotation detector 13 is connected to a rotor (not shown) of the electric motor 12, and an output side of the rotation detector 13 is connected to the current control unit 22. The output sides of the U-phase current detector 4a, the V-phase current detector 4b, and the W-phase current detector 4c are connected to the current compensator 20. Then, the switching signal output from the PWM signal generation unit 23 is output to the three-phase inverter 11. The current compensation unit 20 and the non-interacting filtering unit 21 are current calculation means in the present invention.

  Next, with reference to FIG. 2 and FIG. 3, the details of mounting around the U-phase current detector 4a to the W-phase current detector 4c will be described. In FIG. 2, a rectangular U-shaped bus bar 2 a, V-phase bus bar 2 b, W, which is a current path of the three-phase inverter 11, is formed on an electronic board 11 a (not shown in FIG. 1) of the three-phase inverter 11. A phase bus bar 2c is provided, and is connected to the motor 12 (see FIG. 1) via a flexible U-phase cable 3a, V-phase cable 3b, and W-phase cable 3c. The U-phase current detector 4a, the V-phase current detector 4b, and the W-phase current detector 4c each have a current detection element 5a, a current detection element 5b, and a current detection element 5c that detect magnetic flux. It is mounted in the form described.

  The U-phase current detector 4a uses the current detection element 5a to detect the magnetic flux generated by the flow of the U-phase current so that the U-phase current detector 4a detects the current flowing through the U-phase bus bar 2a. The direction and the sensing surface of the current detection element 5a are parallel to each other, and are mounted on the electronic substrate 11a so as to be positioned in the vicinity of the U-phase bus bar 2a (see FIG. 3). Similarly, the V-phase current detector 4b has the phase to be detected as V-phase, and the W-phase current detector 4c has the phase to be detected as W-phase, which is similar to the positional relationship between the U-phase current detector 4a and the U-phase bus bar 2a. It is mounted on the electronic board 11a so as to be appropriately positioned. Here, since the U-phase current detector 4a to the W-phase current detector 4c do not have a magnetic iron core, they are small and lightweight, easy to install, downsizing of the apparatus, high density mounting, and reduction in assembly man-hours. , Effective in reducing costs.

Next, the operation will be described. Prior to detailed description, an outline of the effects and the like will be described.
First, a description will be given with reference to FIGS. 1, 3 and 4. The U-phase current detector 4a, the V-phase current detector 4b, and the W-phase current detector 4c are the current detection element 5a, the current detection element 5b, and the current detection element 5c that detect the magnetic flux, and the U-phase bus bar 2a, the V-phase bus bar 2b, The W-phase bus bar 2c is disposed in a positional relationship as shown in FIG. 3 is a side view of the U-phase current detector 4a, the V-phase current detector 4b, and the W-phase current detector 4c as viewed from the direction of arrow A in FIG. In FIG. 3, Δxu represents the distance from the left end of the cross section of the U-phase bus bar 2a to the center in the horizontal direction in FIG. 3 of the cross section of the current detection element 5a. Δyu represents the distance from the vertical center of the cross section of the U-phase bus bar 2a to the vertical center of the cross section of the current detection element 5a.

  Similarly, Δxv represents the distance from the left end of the cross section of the V-phase bus bar 2b to the center in the left-right direction of the cross section of the current detection element 5b. Δyv represents the distance from the vertical center of the cross section of the V-phase bus bar 2b to the vertical center of the cross section of the current detection element 5b. Δxw represents the distance from the left end of the cross section of the W-phase bus bar 2c to the center in the left-right direction of the cross section of the current detection element 5c. Δyw represents the distance from the center in the vertical direction of the cross section of the W-phase bus bar 2c to the center in the vertical direction of the cross section of the current detection element 5c.

In FIG. 3, the magnetic flux Φu is linked to the U-phase current detector 4a, that is, the current detection element 5a by the current flowing through the U-phase bus bar 2a. The number of linkages of the magnetic flux Φu changes depending on the distances Δxu and Δyu with respect to the U-phase bus bar 2a of the current detection element 5a, and the magnetic flux density changes. For this reason, the conversion ratio of the detected current to the output voltage of the U-phase current detector 4a varies according to the distances Δxu and Δyu. The same applies to the distances Δxv and Δyv for the V phase and the distances Δxw and Δyw for the W phase. It is therefore necessary to compensate for these distance variations from product to product.
In addition, the current detection element 5a, the current detection element 5b, and the current detection element 5c that are arranged to detect the current of each phase that is the detection target current are interlinked with magnetic flux generated by the current flowing in the phase other than the detection target phase. To do. This magnetic flux becomes a disturbance to the current of the phase to be detected by the current detection element 5a, the current detection element 5b, and the current detection element 5c, affects its output, and gives a detection error.

  Next, FIG. 4 is a schematic diagram showing a magnetic flux generated by the U-phase current, the V-phase current, and the W-phase current interlinked with the current detection element 5a of the U-phase current detector 4a. In addition to the magnetic flux Φu generated by the U-phase current that is the detection target phase, the detection element 5a also links the magnetic flux Φv generated by the V-phase current that is the non-detection target phase and the magnetic flux Φw generated by the W-phase current. For this reason, the current detection element 5a also detects the magnetic fluxes Φv and Φw due to the current flowing in the non-detection target phase. In particular, in the present invention, since no magnetic iron core is disposed outside the U-phase current detector 4a, V-phase current detector 4b, and W-phase current detector 4c, the magnetic flux caused by the current flowing in the non-detection target phase. The degree of influence is large. In the present invention, the variation in the output flux characteristic inherent in the current detection element 5a, the current detection element 5b, and the current detection element 5c as described above, the current detection element 5a, the current detection element 5b, and the current detection element 5c It is possible to detect current with high accuracy by compensating for variations in distance from the U-phase bus bar 2a, V-phase bus bar 2b, and W-phase bus bar 2c and the influence of magnetic flux due to the current of the non-detection target phase.

  Returning to FIG. 1, as input information for calculation, a signal hsigu whose detection target phase is the U phase by the U phase current detector 4a is a signal hsigv whose detection target phase is the V phase by the V phase current detector 4b. The signal hsigw whose detection target phase is the W phase by the W phase current detector 4c is output as a voltage signal obtained by converting the detected current into a voltage, and is transmitted to the current compensator 20. In addition, the rotation detector 13 outputs a rotation angle signal Nmsig of the rotor of the electric motor 12 to the current control unit 22.

  The current compensator 20 performs an operation for compensating the voltage signals hsigu, hsigv, and hsigw based on variations in current-to-voltage conversion characteristics for each of the current detectors 4a to 4c, and scales them in common to the U, V, and W phases. The U-phase detector output current issu, the V-phase detector output current isnsv, and the W-phase detector output current issw are calculated.

  Here, the current signal hsigu output from the U-phase current detector 4a is a magnetic flux-to-voltage conversion characteristic unique to the Hall element, which is the magnetic flux detection element 5a constituting the U-phase current detector 4a, and the U-phase bus bar 2a and the U-phase current. The output of the U-phase detector based on the current-to-voltage conversion characteristic as the current-to-electric signal conversion characteristic for each current detector determined by the magnetic flux linkage characteristic depending on the relative position of the detector 4a (see Δxu and Δyu in FIG. 3) It is converted into a current issu. This conversion is expressed as follows:

issu = gu · hsigu (1a)
However, gu is a conversion coefficient indicating the current-to-voltage conversion characteristic of the U-phase current detector 4a, and this conversion coefficient gu is a case where no current flows in the V-phase and W-phase and only current flows in the U-phase. Can be obtained by measuring the output voltage of the U-phase current detector 4a at that time with respect to a predetermined energization current.

Similarly, the V-phase and W-phase detector output currents are also converted in the form of the following equation based on the respective current-to-voltage conversion characteristics.
isnsv = gv · hsigv (1b)
issw = gw · hsigw (1c)

  Similarly to the U-phase conversion coefficient gu, the V-phase conversion coefficient gv is the V-phase current at that time with respect to a predetermined energization current when no current flows in the U-phase and W-phase but only in the V-phase. It can be obtained by measuring the output voltage of the detector 4b. The W-phase conversion coefficient gw is to measure the output voltage of the W-phase current detector 4c at that time with respect to a predetermined energizing current when no current flows in the U-phase and V-phase but only in the W-phase. Can be obtained.

  Subsequently, the non-interacting filtering unit 21 removes the current component of the non-detection target phase included in each of the U-phase detector output current issu, the V-phase detector output current isnsv, and the W-phase detector output current issw, The operation for decoupling is performed to calculate the U-phase current iu, the V-phase current iv, and the W-phase current iw.

  Here, removing the current component of the non-detection target phase from the U-phase detector output current issu determines the U-phase current occupancy, the V-phase current occupancy, and the W-phase current occupancy of the detection result at the time of current detection. , Issu can be multiplied by the occupancy factor of the U-phase current for the whole. Similarly, the removal of the current component of the non-detection target phase from the V-phase detector output current isnsv determines the current occupancy of each of the U, V, and W phases of the detection result at the time of current detection. This can be done by multiplying the current occupation factor. Further, removing the current component of the non-detection target phase from the W-phase detector output current issw determines the current occupancy of each of the U, V, and W phases of the detection result at the time of current detection, This can be done by multiplying by the occupation factor.

The above will be described using mathematical expressions. First, the current information hicu detected by the U-phase current detector 4a based on the currents of the U phase that is the detection target phase and the V and W phases that are the non-detection target phases can be expressed as the following equation.
hicu = 1 · iu + quv · iv + quw · iw (2a)
Here, quv and quw are expressed by normalizing the degree when the V-phase current and the W-phase current affect the U-phase current information with a coefficient that reflects the U-phase current in the U-phase current information hicu, respectively. It is a coefficient.

The V phase and the W phase can be similarly expressed by the following equations.
hicv = qvu · iu + 1 · iv + qvw · iw (2b)
hicw = qwu · iu + qwv · iv + 1 · iw (2c)

  Here, quv and quw are obtained by normalizing the degree when the U-phase current and the W-phase current affect the V-phase current information hicv by a coefficient that reflects the V-phase current in the V-phase current information. Coefficient. qwu and qwv are coefficients obtained by normalizing the degree when the U-phase current and the V-phase current affect the W-phase current information with the coefficient reflected by the W-phase current information hicw, respectively. is there.

  The coefficients qvu and qwu are the values of the V-phase current detector 4b and the W-phase current detector 4c at that time with respect to a predetermined energization current when no current flows in the V-phase and W-phase but only in the U-phase. The output is measured, and the output of the V-phase current detector 4b at that time with respect to a predetermined energization current when current flows only in the V phase, and with respect to the predetermined energization current when current flows only in the W phase, respectively. It is obtained by normalizing with the output of the W-phase current detector 4c at that time. The coefficients quv, qwv, qw, and qvw are obtained in the same manner.

  When the expressions (2a), (2b), and (2c) are combined and expressed as a determinant, the following expression is obtained.

  From the above equation, removing the current component of the non-detection target phase from the current information hicu, hicv, hicw and taking out the current component of the detection target phase results in the inverse matrix of the coefficient matrix Q being [hicu, hicv, hicw] You can do it by riding. This can be expressed as:

  The arithmetic expression of each row of Equation (4) is that the current component of the detection target phase is extracted by multiplying the occupancy coefficient of the detection target phase current with respect to the whole based on the current occupancy of each phase of the detection result at the time of current detection. Applicable.

  From the above, the non-interacting filtering unit 21 multiplies the detector output currents issu, isnsv, and issw for each phase by a predetermined coefficient as shown in the following equation, and removes the current components of the non-detection target phases included in each phase. U phase current iu, V phase current iv, and W phase current iw are calculated.

  Subsequently, the current control unit 22 receives the current command ir, the U-phase current iu, the V-phase current iv, the W-phase current iw, and the rotation angle signal Nmsig output from the rotation detector 13, and performs a known current feedback control calculation. To calculate three-phase voltage commands Vur, Vvr, and Vwr.

  Next, the PWM signal generation unit 23 performs pulse width modulation on the three-phase electrical commands Vur, Vvr, and Vwr based on the DC side voltage Vdc of the three-phase inverter 11, generates a switching signal, and generates U-phase arms 15a, V It outputs to the phase arm 15b and the W-phase arm 15c. The DC side voltage Vdc is used as a reference for the pulse width (degree of modulation) at the time of conversion. The switching elements in the U-phase arm 15a, the V-phase arm 15b, and the W-phase arm 15c perform on and off operations according to the switching signal, and the voltage applied to the electric motor 12 is adjusted.

  In accordance with these procedures, the current flowing through the motor 12 is calculated, and this generates a switching signal in accordance with a desired current command ir, and the U-phase arm 15a, the V-phase arm 15b, and the W-phase arm 15c are controlled by switching. 12 to perform the control.

  As described above, according to this embodiment, the current-to-voltage conversion characteristic varies among the current detectors, that is, due to the variation in the flux-linkage flux-to-output characteristics and the variation in the distance between the magnetic flux detection element and the bus bar. Compensates for variations in detected current versus output signal voltage. Further, the current component of the non-detection target phase mixed in the voltage signals hsigu to hsigw, which is the current detection result of the current detector, is removed. For this reason, even if it is a current detector which does not have a magnetic iron core for magnetism collection and does not calibrate with an adjustment element, it can control with sufficient accuracy, suppressing the fall of current detection accuracy.

Embodiment 2. FIG.
FIG. 5 is a configuration diagram showing a configuration of an electric motor control device using the current detection device according to the second embodiment for carrying out the present invention. In FIG. 5, the motor control device 110 includes a control arithmetic device 101. In the control arithmetic device 101, the current compensation non-interacting filtering unit 24 replaces the current compensation unit 20 and the non-interacting filtering unit 21 as the current calculation unit of FIG. 1. 1 is the same as that of the first embodiment shown in FIG. 1, the same reference numerals are assigned to the corresponding components, and description thereof is omitted.

  The current compensation non-interference filtering unit 24 performs a current-to-electric signal conversion compensation calculation for compensating for variations in current-to-voltage conversion characteristics for each current detector, and non-detection from the detector output current after the current-to-electric signal conversion compensation calculation. The non-interference calculation for removing the current component of the target phase is performed together. The current-to-electrical signal conversion compensation operation for compensating the variation is the operation shown in the above-described equations (1a), (1b), and (1c), and the current detector signals issu, isnsv, hsigw from the current signals hsigu, hsigv, hsigw. isnsw is calculated. The non-interacting operation is an operation represented by Equation (5), and calculates the U-phase current iu, the V-phase current iv, and the W-phase current iw from the above issu, isnsv, and issw. The values of the coefficients gu, gv, and gw in the equations (1a), (1b), and (1c) are the same as those for the U-phase bus detector 2a, V-phase current detector 4a, V-phase current detector 4b, and W-phase current detector 4c. It is determined based on the current-to-voltage conversion characteristics for each current detector in the state of being attached to the phase bus bar 2b and the W phase bus bar 2c, and the coefficients cu to cww in the equation (5) are attached to the three-phase inverter 11. The value is determined based on the reflection degree of the information of the detection target phase current and the non-detection target phase current of each current detector in the state.

  Since these are coefficients based on characteristics determined when the current detectors 4a to 4c are attached to the three-phase inverter 11, the following expressions are obtained by expressing the respective calculations together by a calculation formula.

  However, kuu to kww represent coefficients after multiplication of cuu to cww and gu to gw. As described above, the amount of calculation required to calculate the current value of each phase from the output signal of the current detector is three times multiplication by the current compensation unit 20 in the above-described first embodiment, and the non-interacting filtering unit. In FIG. 21, the multiplication is 9 times and the addition is 6 times. However, in this embodiment, the current compensation deinterference filtering unit 24 needs only 9 multiplications and 6 additions. Each coefficient is determined based on the characteristics of each current detector in the state assembled as a three-phase inverter, and the output of each current detector when the current is supplied to only one phase of the three phases. It can be obtained by measuring.

  From the above, according to the present embodiment, it is possible to compensate for variations in the current-to-voltage conversion characteristics for each current detector, and to calculate the current component of the non-detection target phase mixed in the current detection result. The number of times can be reduced. For this reason, even when using a current detector that does not have a magnetic iron core for collecting magnets and does not calibrate with an adjustment element, it is possible to detect the current with high accuracy while suppressing a decrease in current detection accuracy. The three-phase inverter 11 can be accurately controlled based on the current. Furthermore, it is possible to reduce the resources required for the calculation. For this reason, when the control calculation is realized by an electronic circuit, effects such as a reduction in cost and a reduction in failure rate can be obtained by reducing the number of necessary parts. When the control calculation is performed by software calculation in a microcomputer or the like, the required calculation time per unit discrete period when performing digital control can be shortened by simplifying calculation. As a result, since the unit discrete period itself can be shortened, effects such as an improved response speed of current feedback control can be expected.

Embodiment 3 FIG.
FIG. 6 is a block diagram showing the configuration of the motor control device according to Embodiment 3 for carrying out the present invention. In FIG. 6, the motor control device 210 includes a three-phase inverter 11 and a control arithmetic device 201. The control arithmetic device 201 includes a current compensation unit 20, a current control unit 222, and a PWM signal generation unit 23. The current control unit 222 includes a rotation phase calculation unit 30, a non-interacting three-phase / two-phase coordinate conversion unit 31, a first subtractor 32, a second subtractor 33, a d-axis current control unit 34, and a q-axis current control. A unit 35 and a two-phase / three-phase coordinate conversion unit 36. The current control unit 222 is controlled by a known vector control method that performs feedback control on the rotation orthogonal coordinates. Since other configurations are the same as those of the first embodiment shown in FIG. 1, the same reference numerals are given to the corresponding components and the description thereof is omitted. The current compensation unit 20 and the non-interacting three-phase / two-phase coordinate conversion unit 31 are current calculation coordinate conversion means in the present invention.

  In the above-described vector control method, control is performed by converting three phases into orthogonal coordinates that rotate in synchronization with the magnetic flux of the motor 12 using the three-phase equilibrium condition. Here, an axis that coincides with the magnetic flux vector of the electric motor 12 with the U phase as a magnetic flux reference axis is referred to as a d-axis, and an axis orthogonal thereto is referred to as a q-axis.

  First, the rotation phase calculation unit 30 receives the rotation angle signal Nmsig of the rotor of the electric motor 12 from the rotation detector 13, and calculates the direction of the magnetic flux vector of the electric motor 12 and the angle θ formed with the magnetic flux reference (U phase). The non-interfering three-phase / two-phase coordinate conversion unit 31 and the two-phase / three-phase coordinate conversion unit 36 are output.

  The non-interacting three-phase / two-phase coordinate conversion unit 31 receives the angle θ and the three-phase detector output currents issu, isnsv, and issw from the current compensation unit 20, and the current components of the non-detection target phases included in each of them. In addition, the d-axis current id and the q-axis current iq are calculated by coordinate conversion. The gradual removal of the current component of the non-detection target phase included in the three-phase detector output currents issu, isnsv, issw is performed based on the equation (5). Further, when the three-phase / two-phase coordinate conversion is performed using all three of the three-phase currents iu, iv, and iw, the following expression is obtained.

  Here, when each operation is expressed as a formula, the following formula is obtained.

  However, fuvw_du (θ), fuvw_dv (θ), fuvw_dw (θ), fuvw_qu (θ), fuvw_qv (θ), and fuvw_qw (θ) are the three-phase detector output current issu when calculating the current id and iq, respectively. , Isnsv, issw as a function of the angle θ. Of these functions, the values of the coefficients cu to cww are determined based on the characteristics of the current detectors assembled as the three-phase inverter 11, and the current flows in only one of the three phases. It can be obtained by measuring the output of each current detector.

  Now, assuming that the control operation is performed by software operation in the microcomputer, it is assumed that the operation related to the trigonometric function is performed by referring to a table developed with data having a required resolution. At this time, the amount of calculation required to calculate the d-axis current id and the q-axis current iq from the detector output currents issu, isnsv and issw is 6 multiplications and 4 additions from the equations (8a) and (8b). Table reference is 6 times. On the other hand, when the non-interference calculation and the three-phase / two-phase coordinate conversion are performed separately, the multiplication of nine times, the addition of six times, and the expressions (7a) and (7b) of the expression (5) In three-phase / two-phase coordinate conversion, 6 multiplications, 4 additions (subtraction is counted as addition for convenience of estimating the amount of calculation), and 6 table references are saved. Operationalization is achieved. In addition, fuvw_qu (θ) and fuvw_du (θ), fuvw_qv (θ) and fuvw_dv (θ), and fuvw_qw (θ) and fuvw_dw (θ) are operations different in phase by 90 degrees, so the same data was developed. It may be a table that includes an offset corresponding to a phase of 90 degrees to the angle θ at the time of reference.

  As described above, the non-interacting three-phase / two-phase coordinate conversion unit 31 calculates the d-axis current id and the q-axis current iq and outputs them to the first subtractor 32 and the second subtractor 33. Subsequently, a deviation between the d-axis current command idr and the d-axis current id is detected by the first subtractor 32 and output to the d-axis current control unit 34. Further, a deviation between the q-axis current command iqr and the q-axis current iq is detected by the second subtracter 33 and input to the q-axis current controller 35. Each of the d-axis current controller 34 and the q-axis current controller 35 performs a calculation so that each current and the current command value coincide by proportional integral (PI) calculation or the like, and obtains the d-axis voltage command Vdr and the q-axis voltage command Vqr. calculate.

Subsequently, the two-phase / three-phase coordinate conversion unit 36 inputs the angle θ, the d-axis voltage command Vdr and the q-axis voltage command Vqr, performs coordinate conversion, and calculates the three-phase voltage commands Vur, Vvr, and Vwr. And output to the PWM signal generator 23. The operation of the three-phase inverter 11 is the same as that shown in the first embodiment shown in FIG.
In FIG. 6, the command values idr and iqr are given based on the command speed (rotation speed) or given based on the command torque. For example, when the rotational speed control of the motor is performed, the output torque command is calculated by performing integral control or PI control according to the deviation between the actual rotational speed and the rotational speed target value, and the output torque command and the actual output torque match. Thus, the rotational speed of the electric motor is controlled by controlling the current.

  In the two-phase / three-phase coordinate conversion unit 36, calculation may be performed using only two phases of the three-phase currents iu, iv, iw from the three-phase equilibrium condition. For example, when currents iu and iv for two phases of U and V are used, the coordinate conversion formula is as follows.

  For this reason, when the expression (5) and the above expression are collectively expressed, the following expression is obtained.

  However, fuv_du (θ), fuv_dv (θ), fuv_dw (θ), fuv_qu (θ), fuv_qv (θ), and fuv_qw (θ) are respectively the three-phase detector current issu, The coefficient applied to isnsv and issw is expressed as a function of the angle θ. Also in this case, fuv_du (θ), fuv_dv (θ), fuv_dw (θ), and fuv_qu () are used in the same manner as when three-phase U, V, and W phase currents are used for three-phase / two-phase coordinate conversion. θ), fuv_qv (θ), fuv_qw (θ) can be developed with data having a required resolution, and calculation can be saved by using a table reference method. The same method can be applied to the case where two phases of the V and W phases or the W and U phases are used for the three-phase / two-phase coordinate transformation.

  According to this embodiment, the variation of the current-to-voltage conversion characteristic for each current detector is compensated, and the current component of the non-detection target phase mixed in the current detection result is removed. For this reason, even a current detector that does not have a magnetic core for collecting magnetism and that does not perform calibration with an adjustment element can prevent a decrease in current detection accuracy and can perform control by a vector control method with high accuracy. . In addition, the non-interfering operation for decoupling the current detection result and the three-phase / two-phase coordinate conversion operation in the vector control method are combined into one to save computations. If it is assumed that the calculation is performed by software calculation, the required calculation time per unit discrete period when performing digital control can be shortened. As a result, since the unit discrete period itself can be shortened, effects such as an improved response speed of current feedback control can be expected.

Embodiment 4 FIG.
FIG. 7 is a configuration diagram showing the configuration of the motor control device according to Embodiment 4 for carrying out the present invention. In FIG. 7, the motor control device 310 includes a three-phase inverter 11 and a control arithmetic device 301. The control arithmetic device 301 includes a current control unit 322 and a PWM signal generation unit 23. The current control unit 322 includes a rotation phase calculation unit 30, a current compensation / decoupling / three-phase / two-phase conversion unit 331, a first subtractor 32, a second subtractor 33, a d-axis current control unit 34, q An axial current control unit 35 and a two-phase / three-phase coordinate conversion unit 36 are included. Since other configurations are the same as those of the first embodiment shown in FIG. 1, the same reference numerals are given to the corresponding components and the description thereof is omitted. The current compensation / non-interference / three-phase / two-phase conversion unit 331 is the current calculation coordinate conversion means in the present invention. In this embodiment, a current compensation / non-interference / three-phase / two-phase conversion unit 331 in which the functions of the current compensation unit 20 and the non-interference three-phase / two-phase coordinate conversion unit 31 in FIG. 6 are integrated is provided. It is a thing.

  According to this embodiment, the current compensation / decoupling / three-phase / two-phase conversion unit 331 performs the current-to-electric signal conversion compensation calculation, the non-interference calculation, and the three-phase / two-phase coordinate conversion. Thus, the number of calculations can be further reduced, and the required calculation time per unit discrete period when performing digital control can be shortened. As a result, since the unit discrete period itself can be shortened, effects such as an improved response speed of current feedback control can be expected.

  As described above, according to the present invention, there is provided a current detector that does not have a magnetic core for collecting magnets and does not perform calibration with an adjustment element when detecting the current on the AC side of the three-phase inverter in the motor control device. Even if it is used, the variation in current-to-voltage conversion characteristics for each current detector is compensated, and the current component of the non-detection target phase that is mixed in the current detection result is removed, reducing the decrease in current detection accuracy. Thus, control can be performed with high accuracy. Also, current-to-electrical signal conversion compensation calculation that compensates for variations in individual characteristics of current-to-voltage conversion characteristics for each current detector, and non-interference calculation that removes current components of non-detection target phases that are mixed in the current detection results In addition, since three-phase / two-phase coordinate transformations are performed in a unified manner and saved, it is possible to reduce resources required for the calculation. For this reason, when the control calculation is realized by an electronic circuit, by reducing the number of necessary parts, it is possible to obtain effects such as cost reduction and a failure rate reduction. Further, when the control calculation is performed by software processing using a microcomputer, the required calculation time per unit discrete period when performing digital control can be shortened. As a result, since the unit discrete period itself can be shortened, there is an effect of improving the response speed of the current feedback control.

As described above, according to the current detection device of the present invention,
A plurality of current detectors having a magnetic flux detection element, and a current calculation means,
One of the current detectors is disposed in the vicinity of the detection target conductor through which the detection target current to be detected flows, and other than the current detector, the non-detection conduction through which the non-detection current that is not the detection target flows. One of the current detectors is arranged near the body, and generates a detection target electric signal according to a magnetic flux generated by a detection target current and a non-detection target current and interlinked with its own magnetic flux detection element. The other of them generates a non-detection target electric signal according to the magnetic flux that is generated by the detection target current and the non-detection target current and interlinks with its own magnetic flux detection element,
The current calculation means compensates for the detection target and non-detection target electrical signals in order to compensate for variations in the current-to-electrical signal conversion characteristics of each current detector, and based on the compensated detection target and non-detection target electrical signals. Since the current to be detected is obtained,
Dispersion of current-to-voltage conversion characteristics for each current detector can be compensated, and the current component outside the detection target mixed in the detection target electrical signal that is the current detection result of the current detector is removed to obtain the detection target current. For this reason, it is possible to accurately detect the current without suppressing a decrease in the current detection accuracy without providing a magnetic core for collecting the magnetic current.

  The current calculation means compensates for variations in the current-to-electric signal conversion characteristics of each current detector by performing a current-to-electric signal conversion compensation calculation by multiplying the detection target and non-detection target electric signals by a predetermined compensation coefficient. Therefore, it is possible to compensate for variations in the current-to-electrical signal conversion characteristics of each current detector by performing a current-to-electrical signal conversion compensation calculation.

Furthermore, the current calculation means compensates for variations in the current-to-electrical signal conversion characteristics of each current detector by performing a current-to-electrical signal conversion compensation calculation by multiplying the detection target and non-detection target electrical signals by a predetermined compensation coefficient. Is,
The current calculation means obtains the detection target current by performing a predetermined non-interference calculation based on the detection target subjected to the current-to-electrical signal conversion compensation calculation and the non-detection target electric signal. So
It is possible to compensate for variations in current-to-electrical signal conversion characteristics of each current detector, and to perform non-interference calculation to remove current components outside the detection target included in the detection target electric signal and to detect Since the current is obtained, it is possible to accurately detect the current without suppressing a decrease in the current detection accuracy without providing a magnetic core for collecting the magnetic current.

Further, the current calculation means is characterized in that the current-to-electrical signal conversion compensation calculation and the non-interference calculation are performed together,
The number of operations can be reduced, and the operation speed can be increased.

And according to the motor control device of the present invention,
It has a three-phase inverter device, a current detection device, and a switching control device,
The three-phase inverter device has an open / close element, converts DC power to AC power, and supplies it to the motor.
A current detection device is a current detection device according to any one of claims 1 to 4, and detects a current on an AC side of a three-phase inverter device,
Since the open / close control device controls the electric motor by controlling the open / close element based on the alternating current detected by the current detection device,
Dispersion of current-to-voltage conversion characteristics for each current detector can be compensated, and the current component outside the detection target mixed in the detection target electrical signal that is the current detection result of the current detector is removed to obtain the detection target current. Therefore, even if a magnetic core for collecting magnets is not provided, it is possible to accurately detect a current while suppressing a decrease in current detection accuracy, and it is possible to accurately control an electric motor using the detected current.

Furthermore, according to the motor control device of the present invention,
It has a three-phase inverter device, a current detection coordinate conversion device, and a switching control device,
The three-phase inverter device has an open / close element, converts DC power to AC power, and supplies it to the motor via a three-phase conductor.
The current detection coordinate conversion device includes a current detector having a magnetic flux detection element, and current calculation coordinate conversion means,
Each current detector is arranged in the vicinity of the conductor of the detection target phase, and generates an electric signal according to the magnetic flux generated by the current of the detection target phase and the current of the non-detection phase and interlinked with its own magnetic flux detection element. And
The current calculation coordinate conversion means performs a current-to-electric signal conversion compensation calculation by multiplying each electric signal by a predetermined compensation coefficient in order to compensate for variations in the current-to-electric signal conversion characteristics of each current detector. A current of each phase is obtained by performing a predetermined non-interference calculation based on each electric signal subjected to the signal conversion compensation calculation, and d on the rotation orthogonal coordinate synchronized with the magnetic flux vector of the motor from the current of each phase. A three-phase / two-phase coordinate calculation for obtaining an axial current and a q-axis current, and a non-interference calculation and a three-phase / two-phase coordinate calculation are performed together.
Since the open / close control device controls the electric motor by controlling the open / close element based on the d-axis current and the q-axis current,
It is possible to compensate for variations in current-to-voltage signal conversion characteristics for each current detector, and to remove the current component outside the detection target mixed in the detection target electrical signal that is the current detection result of the current detector, and to detect the detection target current. Therefore, even if a magnetic core for collecting magnetism is not provided, it is possible to accurately detect a current while suppressing a decrease in current detection accuracy, and it is possible to accurately control an electric motor using the detected current. . In addition, since the non-interference calculation and the three-phase / two-phase coordinate calculation are performed together, the number of calculations can be reduced, and the control accuracy can be improved by increasing the calculation speed.

  Further, the current calculation coordinate conversion means is characterized in that the current-to-electrical signal conversion compensation calculation, the non-interference calculation, and the three-phase / two-phase coordinate conversion are performed together, so that the number of calculations is further increased. Can be reduced.

It is a block diagram which shows the structure of the electric motor control apparatus using the electric current detection apparatus which is Embodiment 1 of this invention. It is a perspective view which shows the arrangement | positioning relationship between each phase bus bar of U, V, and W and the current detector of each phase. It is a side view which similarly shows the arrangement | positioning relationship between each phase bus bar and the current detector of each phase. It is a schematic diagram which shows what is linked to the current detection element of a U-phase current detector among magnetic fluxes generated by a U-phase current, a V-phase current, and a W-phase current. It is a block diagram which shows the structure of the electric motor control apparatus using the electric current detection apparatus which is Embodiment 2 of this invention. It is a block diagram which shows the structure of the electric motor control apparatus which is Embodiment 3 of this invention. It is a block diagram which shows the structure of the electric motor control apparatus which is Embodiment 4 of this invention.

Explanation of symbols

1 control arithmetic device, 2a U-phase bus bar, 2b V-phase bus bar, 2c W-phase bus bar,
3a U phase wiring, 3b V phase wiring, 3c W phase wiring, 4a U phase current detector,
4b V-phase current detector, 4c W-phase current detector,
10, 101, 201 Electric motor control device, 11 Three-phase inverter, 12 Electric motor,
13 Rotation detector, 15a U-phase arm power conversion semiconductor,
15b V-phase arm power conversion semiconductor, 15c W-phase arm power conversion semiconductor,
20 current detection unit, 21 decoupling filtering unit, 22, 222 current control unit,
23 PWM signal generator, 30 rotational phase calculator,
31 non-interacting three-phase / two-phase coordinate conversion unit, 32 first computing unit, 33 second computing unit,
34 d-axis current controller, 35 q-axis current controller, 36 two-phase / three-phase coordinate converter,
331 Current compensation / non-interference / three-phase / two-phase converter.

Claims (7)

A plurality of current detectors having a magnetic flux detection element, and a current calculation means,
One of the current detectors is arranged in the vicinity of a detection target conductor through which a detection target current to be detected flows, and other than the current detector, a detection target through which a non-detection target current flows. One of the current detectors is arranged in the vicinity of an outer conductor, and one of the current detectors generates an electric signal to be detected according to the magnetic flux generated by the electric current to be detected and the electric current not to be detected and interlinked with the magnetic flux detecting element. Emits a non-detection target electric signal in accordance with a magnetic flux generated by the detection target current and the non-detection target current and interlinked with its own magnetic flux detection element,
The current calculation means compensates the detection target and non-detection target electrical signals in order to compensate for variations in current-to-electric signal conversion characteristics of the current detectors, and compensates the detection target and non-detection target electrical signals. A current detection device for obtaining the detection target current based on a signal. The current calculation means compensates for variations in the current-to-electrical signal conversion characteristics of each current detector by performing a current-to-electrical signal conversion compensation calculation by multiplying the detection target and non-detection target electrical signals by a predetermined compensation coefficient. The current detection device according to claim 1, wherein: The current calculation means compensates for variations in the current-to-electrical signal conversion characteristics of each current detector by performing a current-to-electrical signal conversion compensation calculation by multiplying the detection target and non-detection target electrical signals by a predetermined compensation coefficient. Is what
The current calculation means obtains the detection target current by performing a predetermined non-interference calculation based on the detection target and the non-detection target electric signal on which the current-to-electric signal conversion compensation calculation is performed. The current detection device according to claim 1, characterized in that: 4. The current detection device according to claim 3, wherein the current calculation means collectively performs the current-to-electrical signal conversion compensation calculation and the non-interference calculation. It has a three-phase inverter device, a current detection device, and a switching control device,
The three-phase inverter device has an open / close element, converts DC power to AC power, and supplies the motor to the motor.
The current detection device is a current detection device according to any one of claims 1 to 4, wherein the current detection device detects a current on an AC side of the three-phase inverter device,
The open / close control device controls the electric motor by performing open / close control of the open / close element based on the current on the AC side detected by the current detection device. It has a three-phase inverter device, a current detection coordinate conversion device, and a switching control device,
The three-phase inverter device has an open / close element, converts DC power to AC power, and supplies the electric power to the motor via a three-phase conductor.
The current detection coordinate conversion device includes a current detector having a magnetic flux detection element, and current calculation coordinate conversion means,
Each of the current detectors is arranged in the vicinity of the conductor of the detection target phase, and is generated by the current of the detection target phase and the current of the non-detection phase, and the magnetic flux interlinking with the magnetic flux detection element of its own. In response, each sends an electrical signal,
The current calculation coordinate conversion means performs a current-to-electric signal conversion compensation calculation by multiplying each electric signal by a predetermined compensation coefficient in order to compensate for variations in current-to-electric signal conversion characteristics of each current detector. The current of each phase is obtained by performing a predetermined non-interference calculation based on each electric signal subjected to the current-to-electric signal conversion compensation calculation, and the rotation synchronized with the magnetic flux vector of the motor from the current of each phase A three-phase / two-phase coordinate calculation for obtaining the d-axis current and the q-axis current on the Cartesian coordinates, wherein the non-interference calculation and the three-phase / two-phase coordinate calculation are performed together. And
The opening / closing control device controls the electric motor by controlling opening / closing of the opening / closing element based on the d-axis current and the q-axis current. 7. The current calculation coordinate conversion means performs the current-to-electrical signal conversion compensation calculation, the non-interference calculation, and the three-phase / two-phase coordinate conversion together as one. The current detection device described in 1.

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