WO2011111413A1 - 電流検出装置 - Google Patents
電流検出装置 Download PDFInfo
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- WO2011111413A1 WO2011111413A1 PCT/JP2011/050457 JP2011050457W WO2011111413A1 WO 2011111413 A1 WO2011111413 A1 WO 2011111413A1 JP 2011050457 W JP2011050457 W JP 2011050457W WO 2011111413 A1 WO2011111413 A1 WO 2011111413A1
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P27/00—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage
- H02P27/04—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage
- H02P27/06—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using dc to ac converters or inverters
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
- G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
- G01R15/20—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using galvano-magnetic devices, e.g. Hall-effect devices, i.e. measuring a magnetic field via the interaction between a current and a magnetic field, e.g. magneto resistive or Hall effect devices
- G01R15/202—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using galvano-magnetic devices, e.g. Hall-effect devices, i.e. measuring a magnetic field via the interaction between a current and a magnetic field, e.g. magneto resistive or Hall effect devices using Hall-effect devices
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/0092—Arrangements for measuring currents or voltages or for indicating presence or sign thereof measuring current only
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/34—Testing dynamo-electric machines
- G01R31/343—Testing dynamo-electric machines in operation
Definitions
- the present invention relates to a current detection device that detects a current flowing through a conductor using the Hall effect.
- a motor (rotary electric machine) is feedback controlled based on a detection result of a current flowing through the motor.
- This current is measured, for example, by a current sensor that obtains a current value by detecting a magnetic flux generated by the current with a magnetic detection element such as a Hall element.
- Magnetic flux is generated to circulate in the current path according to the right-handed screw law. Therefore, the detection accuracy has been improved by collecting the magnetic flux generated by the current flowing through the current path (conductor) through the current collecting core of the magnetic material formed in an annular shape. It was.
- Patent Document 1 introduces an example of such a coreless current sensor.
- the current concentrates on the conductor surface due to the skin effect.
- the distribution of the magnetic field generated around the bus bar also becomes nonuniform according to the cross-sectional shape of the bus bar.
- the magnetic detection element is installed on the basis of the geometric center position of the bus bar so that the magnetic flux detection direction is adapted to the steady state magnetic field. For this reason, the magnetic flux density detected by the magnetic detection element, in which the distribution of the magnetic field is not uniform with respect to the geometric center position of the bus bar due to the skin effect, is reduced. As a result, there is a possibility that the current measurement accuracy may be lowered, for example, the output value of the current sensor may be higher or lower than the original value, or the transient response may be delayed.
- the characteristic configuration of the current detection device is as follows.
- a sensor unit that is installed in the vicinity of an outer conductor whose cross-sectional shape has a non-uniform distance from the center of gravity to the outer peripheral surface, and detects a magnetic flux in a predetermined magnetic flux detection direction;
- a current detection unit for detecting a current flowing through the conductor based on a detection value of the sensor unit;
- a current frequency acquisition unit for acquiring a current frequency that is a frequency of a current flowing through the conductor;
- a correction unit that corrects the detection value of the sensor unit based on the current frequency.
- the current detection device includes the current frequency acquisition unit that acquires the current frequency that is the frequency of the current flowing through the conductor. Therefore, the current detection device can consider the influence of the skin effect when detecting the current of the conductor based on the detection value of the sensor unit. Specifically, since the detection value of the sensor unit is corrected based on the current frequency by providing the correction unit, the current detection device can suppress the influence of the skin effect and suppress the accuracy even if the skin effect occurs. It is possible to detect the current flowing through the conductor well.
- the current frequency acquisition unit It is preferable to acquire the current frequency based on the rotation speed of the AC rotating electric machine.
- the rotational speed and rotational position of the rotor are acquired, and feedback control is performed.
- a rotation detection device such as a resolver is installed in a control device for an AC rotating electrical machine, or a rotation detection unit that electrically calculates a rotation speed and a rotation position is provided.
- the frequency of the drive current and the generated current flowing through the conductor is almost linear with the rotational speed of the AC rotating electrical machine. Therefore, when the AC rotating electric machine is controlled, the current detection device can be simplified by acquiring the current frequency by using the rotation speed that is almost always acquired.
- the current frequency acquisition unit acquires the current frequency based on a detection result of the sensor unit or the current detection unit.
- the direction of the magnetic flux generated by the current flowing through the conductor is switched depending on the direction of the current. That is, the frequency at which the direction of the magnetic flux is switched and the current frequency are almost linear. Therefore, the current frequency acquisition unit can acquire the current frequency based on the frequency of the magnetic flux detected by the sensor unit. Further, since the magnetic flux density and the current have linearity, it is possible to obtain the current frequency from the current frequency obtained based on the detection value of the sensor unit. Note that the “detected value of the sensor unit” at this time is not affected by the presence or absence of correction by the correction unit.
- the system can be constructed with only the current detection device without using other sensors. It can be simplified.
- the correction unit of the current detection device corrects the detection value by multiplying the detection value of the sensor unit by a coefficient corresponding to the current frequency.
- the configuration of the correction unit and the current detection device can be simplified.
- the correction unit of the current detection device corrects the detection value by changing a dynamic range of the sensor unit according to the current frequency. Since the dynamic range of the sensor unit, which is the most upstream functional unit of the current detection device, is changed, it is possible to suppress the influence of transmission errors and discrete errors during digital conversion.
- the correction unit of the current detection device corrects the detection value based on a map in which a correction value corresponding to the current frequency is stored.
- the current detection device can be configured using hardware with low calculation performance, and calculation errors and the like can be suppressed.
- correction based on the map is useful.
- the effect of this invention is more remarkable when the said cross-sectional shape of the said conductor in which the said sensor part of the electric current detection apparatus which concerns on this invention is installed is a flat shape containing a rectangle and an ellipse.
- the outer shape of the conductor is a shape in which the distance from the center of gravity to the outer peripheral surface is non-uniform in the cross-sectional shape, but the non-uniformity in the distance from the center of gravity to the outer peripheral surface is particularly high in the flat shape. Therefore, the sensor unit is easily affected by the skin effect.
- the current detection device has the above-described configuration, the influence due to the skin effect is suppressed.
- a conductor having a flat cross section such as a plate is often used. Therefore, it is possible to detect the current flowing through the conductor with high accuracy while suppressing the influence of the skin effect on the frequently used conductor.
- the figure which shows the structural example of the drive device of a rotary electric machine typically
- the block diagram which shows an example of the embodiment of an electric current detection apparatus typically
- positioning of the sensor part with respect to a bus-bar Explanatory drawing which shows the influence on the magnetic field detection by the skin effect by a sectional view Graph showing the effect of skin effect on magnetic field detection by attenuation rate
- Block diagram schematically showing an example of the configuration of the current detection device Block diagram schematically showing another example of the configuration of the current detection device
- positioning of the sensor part with respect to a bus-bar typically 10 is a graph showing the influence on the magnetic field detection by the skin effect in the arrangement of FIG. Sectional drawing which shows the other example of the cross-sectional shape of a bus-bar
- the current detection device 1 detects a drive current (generated current) of an AC rotating electrical machine.
- the current detection device 1 is applied to a driving device 20 of a rotating electrical machine MG that is driven by a three-phase alternating current.
- the current detection device 1 is installed in the vicinity of bus bars (conductors) 2U, 2V, and 2W through which drive currents (generated currents) of the three phases of U phase, V phase, and W phase flow.
- the bus bars 2U, 2V, and 2W supply driving current when the rotating electrical machine MG functions as an electric motor, and regenerate the generated current when functioning as a generator.
- the term “bus bar 2” is used as a general term for the U-phase bus bar 2U, the V-phase bus bar 2V, and the W-phase bus bar 2W.
- the drive device 20 includes a control unit 11, a driver circuit 12, a rotation detection device 13, a DC power supply 14, a smoothing capacitor 15, and an inverter 16.
- the DC power source 14 is a rechargeable secondary battery such as a battery.
- the driving device 20 converts the direct current power of the direct current power source 14 into a three-phase alternating current having a predetermined frequency, and supplies it to the rotating electrical machine MG.
- the driving device 20 converts AC power generated by the rotating electrical machine MG into DC and supplies it to the DC power source 14.
- the rotation detection device 13 is configured by a resolver or the like, and outputs a detection signal of the rotation speed of the rotating electrical machine MG and the rotation position of the rotor to the control unit 11.
- the smoothing capacitor 15 is connected in parallel between the positive terminal and the negative terminal of the DC power supply 14, and smoothes the voltage of the DC power supply 14.
- the inverter 16 includes a plurality of switching elements.
- An IGBT insulated gate bipolar transistor
- MOSFET metal oxide field semiconductor effect transistor
- IGBT is used as a switching element.
- the inverter 16 includes a U-phase leg 17U, a V-phase leg 17V, and a W-phase leg 17W corresponding to each phase (three phases of U phase, V phase, and W phase) of the rotating electrical machine MG.
- Each leg 17U, 17V, 17W includes a set of two switching elements each composed of an IGBT 18A of the upper arm and an IGBT 18B of the lower arm connected in series.
- a flywheel diode 19 is connected in parallel to each IGBT 18A, 18B.
- the U-phase leg 17U is connected to the U-phase coil of the rotating electrical machine MG via the U-phase bus bar 2U, and the V-phase leg 17V is connected to the V-phase coil of the rotating electrical machine MG via the V-phase bus bar 2V.
- Leg 17W is connected to a W-phase coil of rotating electrical machine MG via W-phase bus bar 2W.
- each bus bar 2U, 2V, 2W is connected between the emitter of IGBT 18A in the upper arm of each phase leg 17U, 17V, 17W and the collector of IGBT 18B in the lower arm and between each phase coil of rotating electrical machine MG. Are electrically connected.
- the collector of the IGBT 18A in the upper arm of each leg 17U, 17V, 17W is connected to a high voltage power line connected to the positive terminal of the DC power supply 14, and the emitter of the IGBT 18B in the lower arm of each leg 17U, 17V, 17W is , Connected to the ground line connected to the negative terminal of the DC power supply 14.
- the inverter 16 is connected to the control unit 11 via the driver circuit 12 and performs a switching operation according to a control signal generated by the control unit 11.
- the control unit 11 is configured as an ECU (electronic control unit) 10 having a logic circuit such as a microcomputer 10a as a core.
- the ECU 10 is configured to include an interface circuit (not shown) and other peripheral circuits in addition to the microcomputer 10a.
- the interface circuit includes EMI (electro-magnetic interference) countermeasure parts, a buffer circuit, and the like.
- the microcomputer 10a includes a CPU core 10b, a program memory 10c, a work memory 10d, an A / D converter 10e, a communication control unit (not shown), a timer, a port, and the like.
- the CPU core 10b is the core of the microcomputer 10a, and includes an instruction register, an instruction decoder, an ALU (arithmetic logic unit) that performs various operations, a flag register, a general-purpose register, an interrupt controller, and the like.
- the program memory 10c is a non-volatile memory that stores a rotating electrical machine control program, a current detection program, and various parameters that are referred to when these programs are executed.
- the program memory 10c is preferably composed of, for example, a flash memory.
- the work memory 10d is a memory that temporarily stores temporary data during program execution.
- the work memory 10d is preferably composed of DRAM (dynamic RAM) or SRAM (static RAM) that is volatile and can read and write data at high speed.
- DRAM dynamic RAM
- SRAM static RAM
- the A / D converter 10e and the memories 10c and 10d, in addition to the CPU core 10b, are shown integrated on one chip.
- a computer system may be constructed by a plurality of chips.
- the DC power supply 14 is at a high voltage, and the IGBTs 18A and 18B of the inverter 16 switch the high voltage.
- the potential difference between the high level and the low level of the pulsed gate drive signal input to the gate of the IGBT that switches the high voltage is much higher than the operating voltage of a general electronic circuit such as a microcomputer. Voltage. Therefore, the gate drive signal is input to the IGBTs 18 ⁇ / b> A and 18 ⁇ / b> B of the inverter 16 after voltage conversion and insulation via the driver circuit 12.
- the inverter 16 converts the DC power from the DC power supply 14 into three-phase AC power having a predetermined frequency and current value and converts it into the rotating electrical machine MG. Supply. Further, the inverter 16 converts the three-phase AC power generated by the rotating electrical machine MG into DC power and supplies it to the DC power supply 14 when the rotating electrical machine MG functions as a generator (when performing regenerative operation).
- the rotating electrical machine MG is driven at a predetermined output torque and rotation speed under the control of the control unit 11.
- the value of the current flowing through the stator coil (U-phase coil, V-phase coil, W-phase coil) of the rotating electrical machine MG is fed back to the control unit 11.
- the control unit 11 drives and controls the rotating electrical machine MG by executing PI control (proportional integral control) and PID control (proportional calculus control) according to the deviation from the target current. Therefore, the current detection device 1 detects the current value flowing through the phase bus bars 2U, 2V, 2W provided between the phase legs 17U, 17V, 17W of the inverter 16 and the phase coils of the rotating electrical machine MG.
- PI control proportional integral control
- PID control proportional calculus control
- the current detection device 1 is configured to include a sensor unit 6 that is arranged for all of the three bus bars 2U, 2V, and 2W. That is, this current detection device 1 includes a U-phase sensor unit 6U for detecting the current of the U-phase bus bar 2U, a V-phase sensor unit 6V for detecting the current of the V-phase bus bar 2V, and a current of the W-phase bus bar 2W. A W-phase sensor unit 6W is provided. Each phase sensor unit 6U, 6V, 6W detects the magnetic flux density of the magnetic field generated by the current flowing through each phase bus bar 2U, 2V, 2W to be detected, and outputs a detection signal corresponding to the detected magnetic flux density of the magnetic field To do.
- the magnetic flux density at a predetermined position in the magnetic field generated by the current flowing through the bus bar 2 is proportional to the magnitude of the current flowing through the bus bar 2. Therefore, the current value flowing through each phase bus bar 2U, 2V, 2W can be detected by each phase sensor unit 6U, 6V, 6W. In addition, since the current of each phase of the three phases is balanced and the instantaneous value is zero, the current value of only two phases may be detected.
- the current detection device 1 is configured using an ECU 10.
- the sensor unit 6 outputs a detection value corresponding to the magnetic flux density to the ECU 10 as an analog signal, and the detection value is converted into a digital value by the A / D converter 10e of the ECU 10.
- the detected value corresponding to the magnetic flux density is converted into a current value by the cooperation of hardware such as the CPU core 10b and work memory 10d of the microcomputer 10a and software such as a current detection program stored in the program memory 10c. Converted.
- a functional unit that functions as the current detection device 1 by cooperation of hardware and software is referred to as a signal processing unit 11a in the control unit 11 (see FIGS. 7 and 8).
- the current value may be obtained as an analog signal using an operational amplifier or the like, or the current value may be obtained only by hardware without using software.
- the ECU 10 that also functions as the control unit 11 receives detection signals for the rotation speed and rotation position of the rotating electrical machine MG by the rotation detection device 13. Is done. Based on these detection values and detection signals, the microcomputer 10a cooperates with hardware such as the CPU core 10b and software such as a rotating electrical machine control program stored in the program memory 10c, so that each IGBT 18A of the inverter 16 , 18B control signals are generated. The generated control signal is output to the inverter 16 via the driver circuit 12 as described above.
- a functional unit that controls the inverter 16 by cooperation of hardware and software is referred to as an inverter control unit 11b in the control unit 11 (see FIGS. 7 and 8).
- each phase bus bar 2U, 2V, 2W and each phase sensor unit 6U, 6V, 6W and the configuration of each phase sensor unit 6U, 6V, 6W are the same, hereinafter, only the bus bar 2 and the sensor unit will be described. This will be described as 6.
- the sensor unit 6 is disposed in the vicinity of the bus bar 2.
- the bus bar 2 is a plate-like conductor whose cross-sectional shape perpendicular to the direction in which the current flows is a rectangular flat shape, and is made of a metal such as copper or aluminum.
- the sensor unit 6 is installed in the vicinity of the extending surface of the bus bar 2 located on the long side (longitudinal side / long axis side) of the cross section.
- the magnetic flux collecting core 30 as shown in FIG. 13, that is, the magnetic flux collecting core 30 that circulates around the conductor 2A is not installed.
- the magnetic flux collecting core 30 is a magnetic core having a C-shaped cross section with a gap, and converges the magnetic flux generated by the current flowing through the conductor 2A and guides it to the sensor unit 6A installed between the gaps. Therefore, the current detection device 1 of the present embodiment is a so-called coreless type current detection device in which the sensor unit 6 is installed without a magnetic flux collecting core that goes around the conductor.
- a sensor device in which a magnetic body that changes the direction of the magnetic flux or locally concentrates the magnetic flux is integrated with a Hall element or the like has been put into practical use.
- a sensor device is used as the sensor unit 6, if a magnetic flux collecting core that circulates around the conductor is not used, it will be treated as a coreless type current detection device here.
- the sensor unit 6 is configured by using various magnetic detection elements such as a Hall element, an MR (magnetoresistance effect) element, and an MI (magnetic impedance) element.
- the sensor unit 6 is configured as an integrated circuit (IC) chip in which a Hall element 61 and a buffer amplifier 62 that at least impedance-converts the output of the Hall element 61 are integrated. Then, this IC chip is mounted on the substrate 6 a and installed in the vicinity of the bus bar 2.
- the substrate 6 a and the ECU 10 are connected by a power line that drives an IC chip as the sensor unit 6 and a signal line that transmits a detection value by the sensor unit 6.
- the sensor part 6 is arrange
- the IC chip as the sensor unit 6 is located on the long side of the cross section of the bus bar 2, which is a magnetic flux parallel to the chip surface of the IC chip.
- a magnetic flux parallel to the extending surface can be detected. That is, the sensor unit 6 is configured to detect only the magnetic flux density B of the magnetic flux in the predetermined magnetic flux detection direction S. Since the current flowing through the bus bar 2 is an alternating current, the magnetic flux detection direction S includes two directions opposite to each other as shown in FIGS. In FIG. 4, in order to facilitate understanding, magnetic lines of force H when the current I goes from the front to the back of the page are illustrated, and the magnetic flux density B in that case is illustrated.
- each sensor unit 6 is generated by the current I flowing through the bus bar 2 in order to detect the current I flowing through the bus bar 2 with one bus bar 2 as a detection target.
- Magnetic flux magnetic flux density B
- the sensor unit 6 is disposed in the vicinity of the bus bar 2. If the temperature resistance performance and the vibration resistance performance are satisfied, the sensor unit 6 may be installed in a state of being in contact with the bus bar 2. In the present embodiment, as shown in FIGS. 3 and 4, the sensor unit 6 is arranged in a state of being separated from the bus bar 2 by a predetermined distance (h).
- the sensor unit 6 is arranged so that the magnetic flux detection direction S and the extending direction L of the bus bar 2 are substantially orthogonal to each other. Since the extending direction L of the bus bar 2 corresponds to the current flow direction, a strong magnetic flux is obtained in the sensor unit 6. As shown in FIG. 4, the distance between the center of the bus bar 2 (center of current I) and the center of the sensor unit 6 (center of the Hall element) is h, and the longitudinal side of the cross section of the bus bar 2 (surface facing the sensor unit 6). Side) is W.
- FIG. 5 is a diagram showing the influence of the skin effect on the magnetic field detection by a cross-sectional view similar to FIG. FIG. 5A shows the case where the current I is flowing evenly through the bus bar 2, and the current I is shown at the center for the sake of convenience as in FIG. In this case, since the tangent to the magnetic force line H passing through the sensor unit 6 and the magnetic flux detection direction S are parallel, all components of the magnetic flux density B in the sensor unit 6 are detected by the sensor unit 6.
- FIG. 5B shows a case where the current is deflected and flows on the surface of the bus bar 2 due to the skin effect.
- the currents I1 and I1 are dispersed at the vertices of the rectangular cross section farthest from the center.
- Current I is shown as flowing through I2, I3 and I4.
- the magnetic field lines H of the magnetic field due to the current I1 are shown as representatives among the currents flowing through the vertices.
- the tangent to the magnetic force line H passing through the sensor unit 6 and the magnetic flux detection direction S are not parallel.
- the magnetic flux density B in the sensor unit 6 only the magnetic flux density B 1 that is a component parallel to the magnetic flux detection direction S by vector decomposition is detected by the sensor unit 6.
- the detected magnetic flux density B (B1) is a value attenuated with respect to the current I flowing through the bus bar 2. Further, since the relative distance between the currents I1, I2, I3, I4 dispersed at each vertex and the sensor unit 6 is longer than that in FIG. 5A, the amount of magnetic flux in the sensor unit 6 is also reduced. For this reason, the detected magnetic flux density B is a value attenuated with respect to the current I flowing through the bus bar 2.
- FIG. 6 is a graph showing such an attenuation rate.
- the attenuation rate corresponding to the current frequency is shown with the attenuation rate of the current frequency f0 or less at which the skin effect begins to appear as 1.
- the current detector 1 detects the magnetic flux density B with high accuracy while suppressing the influence of the skin effect, and detects the current I based on the detected magnetic flux density B (detected value). For this reason, as shown in FIG.7 and FIG.8, the electric current detection apparatus 1 acquires the electric current frequency which is the frequency of the electric current I which flows through the bus-bar 2, and the sensor part 6 based on electric current frequency. And a correction unit 5 that corrects the detection value.
- the magnetic flux density B is detected by the sensor unit 6 installed in the vicinity of the bus bar 2 as described above. And the value of the electric current I is calculated by the electric current detection part 3 based on said Formula (1).
- the current detection device 1 includes a sensor unit 6 and a signal processing unit 11a. Further, the signal processing unit 11 a is configured with the inverter control unit 11 b in the ECU 10 configuring the control unit 11.
- the signal processing unit 11a and the inverter control unit 11b are configured using the same microcomputer 10a in the same ECU 10 is illustrated. It is not limited. Both may be configured in different ECUs, or may be configured using different microcomputers even when configured in the same ECU.
- the current frequency acquisition unit 4 acquires a current frequency that is the frequency of the current I flowing through the bus bar 2 by any one or a combination of the following methods (a) to (d).
- the bus bar 2 serves as an AC drive current supply path when the rotating electrical machine MG functions as an electric motor, and serves as an AC generated current regeneration path when the rotating electrical machine MG functions as a generator.
- the frequency of the drive current and the generated current depends on the rotation speed of the rotating electrical machine MG. Therefore, the current frequency acquisition unit 4 can calculate and acquire the current frequency based on the detection result of the rotation detection device 13 that detects the rotation speed of the rotating electrical machine MG.
- the current frequency acquisition unit 4 can calculate and acquire the current frequency based on the frequency of the magnetic flux density B detected by the sensor unit 6.
- the magnetic flux density B and the current I are proportional. Therefore, the current frequency acquisition unit 4 may acquire the current frequency directly from the current frequency calculated by the current detection unit 3 based on the magnetic flux density B.
- the signal processing unit 11a and the inverter control unit 11b are configured using the same microcomputer 10a in the same ECU 10. Therefore, the current frequency acquisition unit 4 may acquire the current frequency by acquiring the frequency of the target current or the voltage frequency of the inverter 16 from the inverter control unit 11b.
- the correction unit 5 corrects the detection value of the sensor unit 6 by correcting the output value of the sensor unit 6 before the current detection unit 3 uses it (see FIG. 7).
- the change of the dynamic range means changing the power supply voltage of the sensor unit 6 constituted by the IC chip and the drive voltage applied to the Hall element 61, or changing the power supply voltage and the amplification factor of the buffer amplifier 62. That is.
- the correction unit 5 multiplies the output value (detection value) of the sensor unit 6 by a correction coefficient k that increases as the current frequency increases, thereby detecting the detection value of the sensor unit 6.
- FIG. 9 is a graph showing an example of such a correction coefficient k.
- the correction coefficient k1 exemplifies a correction coefficient k obtained by approximating a quadratic curve so as to cancel the attenuation rate curve shown in FIG.
- the correction coefficient k2 exemplifies the correction coefficient k obtained by linear approximation.
- the correction coefficient k3 exemplifies a correction coefficient k obtained by further linearly approximating a quadratic curve approximated so as to cancel the attenuation rate curve for each region.
- the correction unit 5 refers to the correction coefficient map in which the correction coefficient k corresponding to the current frequency is stored without using the correction coefficient k approximated to a straight line or a curve. It may be corrected. Moreover, as one aspect, the correction unit 5 may correct the detection value of the sensor unit 6 by referring to a map (correction map) in which a correction value corresponding to the current frequency is stored. For example, it is preferable to use a map that refers to the corrected detection value using the current frequency and the detection value of the sensor unit 6 as arguments. Such a map is stored in the program memory 10c, for example.
- the correction unit 5 corrects the detection value of the sensor unit 6 by expanding the dynamic range of the sensor unit 6 as the current frequency increases.
- the ratio which expands a dynamic range it is the same as that of the correction coefficient k mentioned above. That is, the dynamic range is widened so as to cancel the attenuation rate curve shown in FIG.
- the correction unit 5 may change the dynamic range using a coefficient approximated to a straight line or a curve, or refer to a map (range map) in which a value corresponding to the current frequency is stored. The dynamic range may be changed.
- the correction unit 5 may change the dynamic range by referring to a map (voltage map, amplification factor map) in which the value of the power supply voltage or the amplification factor corresponding to the current frequency is stored. This map is also stored in the program memory 10c, for example.
- the sensor section 6 is installed so that the shape of the cross section orthogonal to the direction in which the current flows is opposed to the extended surface of the bus bar 2 on the long side (long side / long axis side) in the cross section.
- the sensor faces the extending surface located on the short side (short side / short axis side) in the cross section of the flat bus bar 2.
- the part 6 may be installed.
- the center of the generated magnetic field is not greatly deviated from the geometric center of the sensor unit 6.
- the sensor unit 6 is approached.
- FIG. 11 is a graph corresponding to FIG. 6 showing the attenuation rate of the detected value when the current frequency f0 or higher at which the skin effect begins to appear.
- the attenuation rate is a value exceeding 1 and is equivalent to the increase rate. Therefore, it is possible to correct the detection value of the sensor unit 6 as described above by using a correction coefficient k having characteristics almost opposite to those in FIG.
- the block configuration of the current detection device 1 is the same as that shown in FIGS. 7 and 8 except for the value of the correction coefficient k. Since those skilled in the art can easily understand, a specific example and detailed description of the correction coefficient k corresponding to FIG. 9 are also omitted.
- the cross-sectional shape of the conductor is not limited to a rectangle.
- the sensor portion 6 is affected by the skin effect as long as it is a conductor having an outer shape in which the distance from the center of gravity or the geometric center to the outer peripheral surface is non-uniform, and thus the present invention can be applied. That is, if the cross-sectional shape of the conductor is not a perfect circle or a perfect circle, the sensor unit 6 is affected by the skin effect even if it is a square, a diamond, or a regular triangle. Therefore, the cross-sectional shape of the conductor orthogonal to the direction in which the current flows may be a square, rhombus, equilateral triangle, or the like.
- the cross section may be elliptical or polygonal as shown in FIG. 12.
- the influence of the skin effect tends to appear when the ratio between the major axis X and the minor axis Y shown in FIG. 12, that is, the aspect ratio is higher.
- a person skilled in the art can read the “long side of rectangle” in the above description as “long axis” and “short side of rectangle” as “short axis”, so that the The invention could be applied.
- the current detection device of the present invention is not limited to the current flowing through the AC rotating electrical machine, and can be widely applied to applications that detect AC current. However, it goes without saying that such modifications including the gist of the present invention also belong to the technical scope of the present invention.
- the present invention can be applied to a current detection device that detects an alternating current such as a current flowing in an alternating current rotating electrical machine.
- an alternating current such as a current flowing in an alternating current rotating electrical machine.
- the current detection device according to the present invention is suitable when it is difficult to make the cross-sectional shape of the conductor circular or regular polygon due to a large current flow or due to restrictions such as the installation space of the device.
- the present invention can be favorably applied to a current detection device in a rotating electrical machine or the like that is used in an automobile drive device in which a large current flows and the installation space is limited.
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measuring Instrument Details And Bridges, And Automatic Balancing Devices (AREA)
- Control Of Ac Motors In General (AREA)
- Measurement Of Current Or Voltage (AREA)
Abstract
Description
断面形状が重心から外周面までの距離が不均一となる外形形状の導体の近傍に設置され、所定の磁束検出方向の磁束を検出するセンサ部と、
前記センサ部の検出値に基づいて前記導体を流れる電流を検出する電流検出部と、
前記導体を流れる電流の周波数である電流周波数を取得する電流周波数取得部と、
前記電流周波数に基づいて前記センサ部の検出値を補正する補正部と、を備える点にある。
導体の外形形状は、断面形状において、重心から外周面までの距離が不均一となる形状であるが、特に扁平形状であると、重心から外周面までの距離の不均一性が高くなる。従って、センサ部は、表皮効果による影響を受けやすくなる。ここで、電流検出装置が上述したような構成を備えることにより、表皮効果による影響が抑制される。導体の生産性や、引き回しを考慮すると、導体には板状など、断面が扁平形状のものが利用されることが多い。従って、利用頻度の高い導体に関して、表皮効果の影響を抑制して精度良く当該導体に流れる電流を検出することが可能となる。
(b)また、バスバー2を流れる電流Iによって生じる磁界は、電流Iの方向によって磁力線の方向が切り替わる。つまり、磁束の方向が切り替わる周波数は、電流Iの周波数に依存する。従って、電流周波数取得部4は、センサ部6により検出された磁束密度Bの周波数に基づいて電流周波数を演算して取得することが可能である。
(c)また、上記式(1)から明らかなように、磁束密度Bと電流Iとは比例する。従って、電流周波数取得部4は、磁束密度Bに基づいて電流検出部3によって演算された電流の周波数から直接、電流周波数を取得してもよい。
(d)さらに、本実施形態においては、同一のECU10において同一のマイクロコンピュータ10aを用いて信号処理部11a及びインバータ制御部11bが構成されている。従って、電流周波数取得部4は、インバータ制御部11bから目標電流の周波数やインバータ16の電圧周波数などを取得して、電流周波数を取得してもよい。
上記実施形態においては、電流が流れる方向に直交する断面の形状がバスバー2の当該断面における長手側(長辺側・長軸側)に位置する延在面に対向してセンサ部6が設置される場合を例として説明した。しかし、この形態に限定されることなく、図10に示すように、扁平形状のバスバー2の当該断面における短手側(短辺側・短軸側)に位置する延在面に対向してセンサ部6が設置されてもよい。但し、この場合には、表皮効果により図5(b)に示すようにバスバー2の端面に電流Iが集中すると、発生する磁界の中心はセンサ部6の幾何学的な中心から大きくずれることなく、センサ部6に近づくことになる。
2,2U,2V,2W:バスバー(導体)
3:電流検出部
4:電流周波数取得部
5:補正部
6,6U,6V,6W:センサ部
B:磁束密度
I:導体を流れる電流
MG:回転電機(交流回転電機)
S:磁束検出方向
Claims (7)
- 断面形状が重心から外周面までの距離が不均一となる外形形状の導体の近傍に設置され、所定の磁束検出方向の磁束を検出するセンサ部と、
前記センサ部の検出値に基づいて前記導体を流れる電流を検出する電流検出部と、
前記導体を流れる電流の周波数である電流周波数を取得する電流周波数取得部と、
前記電流周波数に基づいて前記センサ部の検出値を補正する補正部と、
を備える電流検出装置。 - 前記導体は、交流回転電機が電動機として機能する際に駆動電流を供給し、発電機として機能する際に発電電流を回生するものであり、前記電流周波数取得部は、前記交流回転電機の回転速度に基づいて前記電流周波数を取得する請求項1に記載の電流検出装置。
- 前記電流周波数取得部は、前記センサ部又は前記電流検出部の検出結果に基づいて前記電流周波数を取得する請求項1に記載の電流検出装置。
- 前記補正部は、前記電流周波数に応じた係数を前記センサ部の前記検出値に乗じて前記検出値を補正する請求項1から3の何れか一項に記載の電流検出装置。
- 前記補正部は、前記電流周波数に応じて前記センサ部のダイナミックレンジを変更することによって前記検出値を補正する請求項1から3の何れか一項に記載の電流検出装置。
- 前記補正部は、前記電流周波数に応じた補正値が記憶されたマップに基づいて前記検出値を補正する請求項1から3の何れか一項に記載の電流検出装置。
- 前記断面形状は、長方形及び楕円形を含む扁平形状である請求項1から6の何れか一項に記載の電流検出装置。
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DE102005042060A1 (de) * | 2005-05-24 | 2006-11-30 | Continental Teves Ag & Co. Ohg | Rückwirkungsfreie Auskopplung von CAN-Bus-Signalen |
JP5702862B2 (ja) * | 2011-08-31 | 2015-04-15 | 本田技研工業株式会社 | 電流検出回路モジュール |
PL2898333T3 (pl) * | 2012-09-24 | 2024-01-15 | Abb Schweiz Ag | Urządzenie czujnika napięcia |
JP6031983B2 (ja) * | 2012-12-06 | 2016-11-24 | 株式会社デンソー | 電流センサ機構 |
CN107209209A (zh) * | 2015-02-06 | 2017-09-26 | 日立汽车系统株式会社 | 电流传感器 |
JP2016217962A (ja) * | 2015-05-25 | 2016-12-22 | 株式会社デンソー | 電流検出装置 |
CN105866722A (zh) * | 2016-06-17 | 2016-08-17 | 重庆所罗门智跑机械有限公司 | 一种电流检测装置及电机驱动系统 |
WO2018142850A1 (ja) * | 2017-02-03 | 2018-08-09 | アルプス電気株式会社 | 電流センサ装置 |
WO2019056095A1 (en) * | 2017-09-19 | 2019-03-28 | Zhang Yiqiang Jake | HELICOIDAL ELECTROMAGNETIC FIELD CONCENTRATOR USING SOFT MAGNETIC MATERIALS |
JP6988684B2 (ja) | 2018-05-18 | 2022-01-05 | 株式会社デンソー | 電流センサ |
JP7021016B2 (ja) * | 2018-07-06 | 2022-02-16 | 株式会社日立製作所 | 電力変換装置 |
JP7313198B2 (ja) * | 2018-08-31 | 2023-07-24 | 旭化成エレクトロニクス株式会社 | 電流センサ、検出装置、検出方法、およびプログラム |
US11047928B2 (en) * | 2019-07-15 | 2021-06-29 | Allegro Microsystems, Llc | Methods and apparatus for frequency effect compensation in magnetic field current sensors |
JP7259632B2 (ja) * | 2019-08-09 | 2023-04-18 | Tdk株式会社 | 電流センサ |
DE102020119340A1 (de) * | 2020-07-22 | 2022-01-27 | Phoenix Contact Gmbh & Co. Kg | Strommessgerät zur Messwerterfassung, Stromsensor sowie Strommessumformer |
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