JP2004222422A - Rotational position detector for rotating machine, and rotating machine controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotational position detector for a rotating machine where the accuracy in positional detection does not deteriorate due to the magnitude of a detected magnetic flux and the disturbance. <P>SOLUTION: A signal processing part 112 (not shown) calculates signals ▵Hu-v, ▵Hv-w, and ▵Hw-u consisting of differences between two signals each using voltage signals (analog signals) corresponding each to the magnitude of detected magnetic flux Hu, Hv, and Hw corresponding to a U phase, a V phase, and a W phase. Then, the signal processing part 112 converts the calculated signal into a digital signal with a threshold as 0, and outputs the converted digital signal as the positional signals Pu*, Pv*, and Pw* of a rotor 2. Accordingly, regardless of the magnitude of the detected magnetic flux, the ON duty time Ton of the positional signal becomes constant, and the duty ratio of the positional signal becomes constant. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a rotation position detection device for a rotating machine and a rotation device control device, and more particularly, to a rotation position detection device and a rotation device control device for a rotation machine that detects the position of a rotor with a magnetic detection element.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as a synchronous AC rotating machine, a rotor (hereinafter, also referred to as “rotor”) includes a permanent magnet, and a magnetic pole formed by the permanent magnet and a fixed armature (hereinafter, also referred to as “stator”). In addition to the permanent magnet type rotating machine that rotates by the magnetic action with the rotating magnetic field generated in the above, a rotor is provided with a field coil, and a field current is passed through the field coil, and the rotor is perpendicular to the rotation axis of the magnetic field generated in the rotor. 2. Description of the Related Art A field winding type rotating machine which rotates by a magnetic action of a direction component and a rotating magnetic field generated in a stator is generally known.
[0003]
Japanese Patent Laid-Open Publication No. Sho 64-43093 discloses a rotary position detecting device that can be used in such a rotating machine. In a three-phase brushless motor, a plurality of Hall elements as position detecting elements are arranged on a stator. It discloses a method of detecting a change in a magnetic field accompanying rotation of a rotor magnet and generating a position signal for sequentially energizing a plurality of stator coils based on each output from a Hall element. Patent Document 1).
[0004]
[Patent Document 1]
JP-A-64-43093
[Patent Document 2]
JP-A-4-71389 [0006]
[Problems to be solved by the invention]
In a field winding type rotating machine that generates a field pole by passing a field current through a field coil, the magnitude of the magnetic field generated in the rotor changes according to the magnitude of the field current, and the position is accordingly adjusted. The magnitude of the magnetic flux detected by the detection element changes. When the magnitude of the detected magnetic flux changes, the duty ratio of the position signal for energizing the stator coil changes.
[0007]
FIG. 9 is a diagram for explaining the relationship between the magnitude of the detected magnetic flux and the position signal in the three-phase AC rotating machine.
[0008]
Referring to FIG. 9, the vertical axis indicates the magnitude of the magnetic flux detected by the magnetic sensor as the position detecting element, and the horizontal axis indicates the phase (electrical angle) of the detected magnetic flux. The magnetic fluxes Hu1, Hv1, and Hw1 indicate changes in the detected magnetic flux corresponding to each phase when the field current is large, and the magnetic fluxes Hu2, Hv2, and Hw2 indicate the detected magnetic fluxes corresponding to each phase when the field current is small. Indicates a change. The magnetic flux Hth is a threshold value for determining whether the position signal output as a digital signal is at an H (logic high) level or an L (logic low) level.
[0009]
As shown in FIG. 9, the times Ton1 and Ton2 when the position signal is turned on differ depending on the magnitude of the detected magnetic flux. Therefore, in the field winding type rotating machine, the duty ratio of the position signal for energizing the stator coil changes unless the change in the magnitude of the magnetic flux is considered, and as a result, the performance of the rotating machine becomes unstable. Or, if the detected magnetic flux is small, there arises a problem that the position signal does not turn on.
[0010]
A specific example in which such a problem occurs is, for example, a case where field weakening control for reducing a field current is performed to secure an output when the rotation speed increases.
[0011]
In addition, when the position detecting element receives disturbance such as a change in the ambient temperature due to heat generated by the coil from the rotor and the stator, and the output signal of the position detecting element changes in accordance with the disturbance, the above-described case also depends on the degree of the received disturbance. There is a possibility that the duty ratio of the position signal thus changed may cause deterioration of the performance of the rotating machine.
[0012]
On the other hand, in the above-mentioned Japanese Patent Application Laid-Open No. Sho 64-43093, a Hall element as a position detecting element is arranged on a stator, but a position detecting element is arranged close to the rotor or the stator, and a magnetic field generated from the rotor is generated. Is detected, the position detection element is greatly affected by a magnetic field generated from the stator, a disturbance due to heat generated by the coil from the stator and the rotor, and the like. Therefore, arranging the position detection element close to the rotor or the stator may cause deterioration of the position detection accuracy.Also, if the detection position is corrected assuming various disturbances, the position detection element is required to be highly advanced. A complicated correction operation is required, which results in an increase in cost.
[0013]
In addition, when the position detecting element is arranged close to the rotor or the stator, in order to enable sensing by the position detecting element, a magnetic piece for sensing is provided on the rotor, or in a field winding type motor, It is necessary to change the shape of the field winding. Therefore, some modification of the rotor is required for sensing, which increases costs.
[0014]
Therefore, the present invention has been made to solve such a problem, and an object of the present invention is to provide a rotation position detecting device for a rotating machine in which the position detection accuracy does not deteriorate due to the magnitude of a detected magnetic flux and disturbance.
[0015]
Another object of the present invention is to provide a rotating machine control device in which the position detection accuracy is not deteriorated by the magnitude of the detected magnetic flux and disturbance.
[0016]
It is a further object of the present invention to provide a low-cost rotary position detecting device for a rotating machine that does not deteriorate the position detection accuracy due to the magnitude of the detected magnetic flux and disturbance.
[0017]
Still another object of the present invention is to provide a low-cost rotary machine control device that does not deteriorate the position detection accuracy due to the magnitude of the detected magnetic flux and disturbance.
[0018]
[Means for Solving the Problems]
According to the present invention, a rotational position detecting device for a rotary machine includes a field coil, and a rotary position detecting device for a rotary machine including a rotor having a field pole formed by flowing a field current through the field coil. Detecting a magnetic flux generated by the field coil and indicating the position of the field pole, and converting a first plurality of signals at a level corresponding to the magnitude of the detected magnetic flux into a plurality of phases. Receiving a first plurality of signals, calculating a level difference between signals corresponding to adjacent phases in the first plurality of signals, and calculating a second plurality of signals obtained by the calculation. A signal processing unit that outputs the position signal of the rotor.
[0019]
Preferably, the signal processing unit outputs the position signal as a digital signal having a constant duty ratio.
[0020]
Preferably, the signal processing unit outputs the corresponding position signal at the first logical level when the level difference is greater than 0, and outputs the corresponding position signal to the first logical level when the level difference is 0 or less. Output at the inverted second logic level.
[0021]
Preferably, the magnetic detection unit receives the first leakage magnetic flux generated by the field coil via a member different from the rotor, and detects the second leakage magnetic flux indicating the position of the field pole based on the first leakage magnetic flux. And a plurality of magnets for detecting a second leakage magnetic flux output from the magnetic pole generation unit and outputting a first plurality of signals at a level corresponding to the magnitude of the second leakage magnetic flux, respectively. And a detection element.
[0022]
Preferably, the magnetic pole generation unit has a radial shape corresponding to the field pole, outputs the second leaked magnetic flux radially by adding the strength of the magnetic flux density corresponding to the field pole to the first leaked magnetic flux. .
[0023]
Preferably, the plurality of magnetic detection elements are arranged in the rotation direction of the magnetic pole generation unit at intervals of an electrical angle obtained by dividing 360 degrees by the number of phases.
[0024]
According to the invention, the rotating machine control device controls any one of the above-described rotating position detecting devices, a driving circuit for driving the rotating machine, and a driving circuit based on a position signal received from the rotating position detecting device. A control circuit.
[0025]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding portions have the same reference characters allotted, and description thereof will not be repeated.
[0026]
FIG. 1 is a sectional view showing a configuration of a rotating machine according to the present embodiment.
Referring to FIG. 1, a rotating machine 1 includes a rotor 2, a field coil 4, a stator 6, a shaft 8, bearings 10 and 12, a brush 14, a pulley 16, a rotating plate 18, And a sensor 20.
[0027]
The rotor 2 is a rotor that is fixed to the shaft 8 and is rotatable by the shaft 8 being supported by bearings 10 and 12. The rotor 2 includes a field coil 4 therein, and a field pole is formed when a field current flows through the field coil 4. The magnetic field generated when a field current flows through the field coil 4 is composed of a main magnetic field composed of a component perpendicular to the rotation axis of the shaft 8 and a magnetic field composed of an axial component of the shaft 8. The rotor 2 is rotated by a magnetic action with the rotating magnetic field generated by 6. The leakage magnetic flux H flowing from the shaft 8 to the rotating plate 18, the stator 6, and the other end of the shaft 8 by the magnetic field composed of the axial component of the shaft 8 is used to detect the rotational position of the rotor 2 as described later. Used as a detection magnetic flux.
[0028]
The field coil 4 is a winding for generating a field pole in the rotor 2, and generates a magnetic field according to the magnitude of a field current flowing through the winding.
[0029]
The stator 6 is a fixed armature including three-phase windings of a U-phase, a V-phase, and a W-phase, and generates a rotating magnetic field acting on the rotor 2 when a three-phase alternating current flows.
[0030]
The shaft 8 is a rotating shaft supported by bearings 10 and 12. The shaft 8 is made of a material having a predetermined strength necessary for transmitting the torque, and is made of a material that easily allows a leakage magnetic flux generated from the rotor 2 to pass therethrough, as described later.
[0031]
The bearings 10 and 12 fix the shaft 8 rotatably. The brush 14 makes sliding contact with a commutator piece electrically connected to the field coil 4, and a field current is supplied to the field coil 4 from the outside via the brush 14 and the commutator piece. Pulley 16 transmits torque between shaft 8 and another rotating shaft.
[0032]
The rotating plate 18 is provided at one end of the shaft 8, is fixed to the shaft 8, and rotates in conjunction with the rotor 2. Similarly to the shaft 8, the rotating plate 18 is made of a material that allows the magnetic flux to easily pass, and radially transmits the leakage magnetic flux received from the shaft 8. The rotation plate 18 has a radial shape corresponding to the field pole of the rotor 2 so that the rotation position of the rotor 2 can be detected by the magnetic sensor 20.
[0033]
The magnetic sensor 20 is a magnetic detection element capable of detecting a magnetic flux, and includes three sensors corresponding to a U phase, a V phase, and a W phase. These sensors are, for example, Hall elements and magnetoresistive elements. The magnetic sensor 20 is arranged close to the rotating plate 18, and is arranged at a position where the leakage magnetic flux H flowing from the rotating plate 18 to the stator 6 is maximum in the radial direction of the rotating plate 18. On the other hand, in the magnetic sensor 20, three sensors are arranged at an electrical angle of 120 degrees with respect to the rotation direction of the rotating plate 18. The magnetic sensor 20 detects leakage magnetic fluxes Hu, Hv, and Hw by three sensors corresponding to the U phase, the V phase, and the W phase, generates a voltage corresponding to the magnitude of the detected magnetic flux, and outputs a signal to be described later. Output to a processing unit (not shown).
[0034]
In the rotating machine 1, the rotational position of the rotor 2 is detected by the magnetic sensor 20 sensing a change in the leakage magnetic flux H. A rotating plate 18 is provided to generate the change in the leakage magnetic flux H. Have been. That is, the rotating plate 18 gives the magnetic flux density corresponding to the field pole of the rotor 2 to the leakage magnetic flux H received from the shaft 8 and radially output. Accordingly, the magnetic sensor 20 detects the leakage magnetic flux H from the rotating plate 18 in which the change in the magnetic field is reproduced without directly detecting the change in the magnetic field generated around the rotor 2 due to the rotation of the rotor 2. By doing so, the rotational position of the rotor 2 can be detected.
[0035]
On the other hand, when the rotational position of the rotor 2 is detected, even when the change in the magnetic field generated around the rotor 2 is directly detected, the change in the leakage magnetic flux H from the rotating plate 18 as in the rotating machine 1 is detected. Even in the case of detection, the magnitude of the magnetic field generated in the rotor 2 changes according to the magnitude of the field current, and as a result, the magnitude of the magnetic flux detected by the magnetic sensor 20 also changes.
[0036]
As shown in FIG. 9, in the field winding type rotating machine, the duty ratio of the position signal for energizing the stator coil is reduced unless the change in the magnitude of the detected magnetic flux is considered. As a result, there arises a problem that the performance of the rotating machine is not stable, or the position signal is not turned on when the detected magnetic flux is small. Furthermore, the duty ratio of the above-mentioned position signal changes depending on the degree of disturbance received by the magnetic sensor 20 such as a change in the ambient temperature, which may cause deterioration in the performance of the rotating machine.
[0037]
Therefore, in the rotating machine 1, a position signal indicating the rotating position of the rotor 2 and the duty of a drive signal for driving the rotating machine 1 using the position signal are used without depending on the magnitude of the leakage magnetic flux H. In a signal processing unit included in a rotating machine control device (not shown), a process of converting a magnetic flux detected by the magnetic sensor 20 into a position signal is performed so that the ratio becomes constant. The rotating machine control device and the signal processing unit included therein will be described later.
[0038]
In the rotating machine 1, when a field current is supplied to the field coil 4, a main magnetic flux is generated, the rotor 2 rotates by a magnetic action with a rotating magnetic field generated by the stator 6, and the shaft 8 A magnetic field of a directional component is also generated, and a loop of leakage magnetic flux H flowing from the shaft 8 to the rotating plate 18, the stator 6, and the other end of the shaft 8 is generated.
[0039]
As described above, the rotating plate 18 has a radial shape corresponding to the field pole of the rotor 2, and the leakage magnetic flux H radially output from the rotating plate 18 corresponds to the field pole of the rotor 2. Since the magnetic flux density is high or low, the magnetic sensor 20 detects this. Leakage magnetic fluxes Hu, Hv, and Hw detected by three sensors corresponding to the U phase, the V phase, and the W phase of the magnetic sensor 20 are converted into position signals having a constant duty ratio by a signal processing unit included in the rotating machine control device. It is converted to Pu *, Pv *, Pw * (digital signal). In this way, the rotational position of the rotor 2 is accurately detected regardless of the magnitude of the field current.
[0040]
FIG. 2 is a sectional view perpendicular to the rotation axis of the rotation plate 18 shown in FIG.
Referring to FIG. 2, rotating plate 18 has a radial shape corresponding to the field pole of rotor 2. In FIG. 2, eight projections are radially provided corresponding to the rotor 2 having 16 poles, and the magnetic flux radially flowing through the rotating plate 18 is concentrated and output from these eight projections. You. That is, the magnetic flux output from the rotating plate 18 is given a magnetic flux density corresponding to the field pole of the rotor 2 and is radially output from the rotating plate 18.
[0041]
FIG. 3 is a diagram illustrating the configuration of the rotor in the rotating machine according to the present invention. In FIG. 3, the configuration of the rotor is conceptually shown and does not correspond to the number of poles of the rotating plate 18 shown in FIG. The numbers match.
[0042]
Referring to FIG. 3, the rotor includes a member 2a and a member 2b, which are combined and include a field coil therein. The member 2a is magnetized to the N pole and the member 2b is magnetized to the S pole by the magnetic field generated by the field coil. Thereby, a large number of N and S poles are alternately formed in the circumferential direction, and a field pole is formed on the rotor. In the shaft 8, a magnetic field is generated by the field coil in a direction from the side indicated by "S" to the side indicated by "N".
[0043]
FIG. 4 is a schematic block diagram of a rotating machine control device 100 that controls the rotating machine 1 shown in FIG.
[0044]
Referring to FIG. 4, rotating machine control device 100 includes DC power supply B, capacitor C1, inverter 102, position detection device 104, and control device 106.
[0045]
Inverter 102 includes a U-phase arm 15, a V-phase arm 16, and a W-phase arm 17. U-phase arm 15, V-phase arm 16, and W-phase arm 17 are provided in parallel between the power supply line and the ground line.
[0046]
U-phase arm 15 includes serially connected MOS transistors Tr1 and Tr4, V-phase arm 16 includes serially connected MOS transistors Tr2 and Tr5, and W-phase arm 17 includes MOS transistors Tr3 and Tr3 connected in series. It consists of Tr6. Diodes D1 to D6 are connected between the sources and drains of the MOS transistors Tr1 to Tr6, respectively, so that the conduction direction is opposite to that of each of the MOS transistors Tr1 to Tr6.
[0047]
An intermediate point of each phase arm is connected to each phase end of each phase coil of the rotating machine 1. That is, the rotating machine 1 is a three-phase synchronous rotating machine, in which one ends of three coils of U, V, and W phases are commonly connected to a middle point, and the other ends of the U-phase coils are MOS transistors Tr1, At the midpoint of Tr4, the other end of the V-phase coil is connected to the midpoint of MOS transistors Tr2 and Tr5, and the other end of the W-phase coil is connected to the midpoint of MOS transistors Tr3 and Tr6.
[0048]
The DC power supply B is composed of a secondary battery such as nickel hydride, lithium ion, or lead. Capacitor C 1 smoothes the DC voltage supplied from DC power supply B, and supplies the smoothed DC voltage to inverter 102.
[0049]
The position detecting device 104 detects leakage magnetic fluxes Hu, Hv, and Hw corresponding to each phase by the rotating plate 18 and the magnetic sensor 20 shown in FIG. The digital signal is converted into a signal, and the converted digital signal is output to the control device 106 as the position signal Pu *, Pv *, Pw * of the rotor 2.
[0050]
Control device 106 drives drive signals Dr1 to Dr6 for driving each of MOS transistors Tr1 to Tr6 included in inverter 102 based on position signals Pu *, Pv * and Pw * of rotor 2 received from position detection device 104. And outputs the generated drive signals Dr1 to Dr6 to the gate terminals of the MOS transistors Tr1 to Tr6, respectively.
[0051]
FIG. 5 is an arrangement diagram of the magnetic sensor 20 shown in FIG. 1 in a direction perpendicular to the rotation axis. Note that FIG. 5 schematically illustrates the arrangement of the magnetic sensor 20 for conceptual description.
[0052]
Referring to FIG. 5, magnetic sensor 20 includes three Hall elements 20a to 20c. The Hall elements 20a to 20c detect leakage magnetic fluxes Hu, Hv, and Hw output from the rotating plate 18, respectively, and generate voltages according to the magnitude of the detected magnetic flux. Then, the magnetic sensor 20 outputs the voltage to a signal processing unit described later.
[0053]
Hall element 20a is arranged so as to form an angle θ with respect to the arrangement direction of the U-phase. Then, the Hall elements 20b and 20c are also arranged in the same manner as the Hall element 20a. The Hall elements 20a to 20c are arranged at intervals of 120 degrees in electrical angle.
[0054]
FIG. 6 is a functional block diagram functionally describing the position detection device 104 shown in FIG. Referring to FIG. 6, position detection device 104 includes a magnetism detection unit 110 and a signal processing unit 112.
[0055]
The magnetic detection unit 110 includes the rotating plate 18 and the magnetic sensor 20 shown in FIG. The magnetic sensor 20 detects the leakage magnetic fluxes Hu, Hv, Hw output from the rotating plate 18 by the three Hall elements 20a to 20c shown in FIG. 5, and respectively corresponds to the magnitudes of the leakage magnetic fluxes Hu, Hv, Hw. A voltage signal (analog signal) is output to the signal processing unit 112.
[0056]
The signal processing unit 112 performs a subtraction process between the two signals on the voltage signals (analog signals) corresponding to the magnitudes of the leakage magnetic fluxes Hu, Hv, and Hw received from the magnetic detection unit 110. Specifically, the signal processing unit 112 performs the following arithmetic processing.
[0057]
ΔHu−v = V (Hu) −V (Hv) (1)
ΔHv−w = V (Hv) −V (Hw) (2)
ΔHw−u = V (Hw) −V (Hu) (3)
Here, V (Hu), V (Hv) and V (Hw) represent voltage signals corresponding to the magnitudes of the detected leakage magnetic fluxes Hu, Hv and Hw, respectively.
[0058]
The signal processing unit 112 converts the signals ΔHu−v, ΔHv−w, and ΔHw−u obtained by the above calculation into digital signals by setting the threshold value to 0, and converts the converted digital signals to the position of the rotor 2. The signals are output to the control device 106 as signals Pu *, Pv *, and Pw *.
[0059]
Thus, by generating the position signals Pu *, Pv *, Pw * based on the signals ΔHu-v, ΔHv-w, ΔHw-u corresponding to the difference between the leakage magnetic fluxes Hu, Hv, Hw, Regardless of the magnitude, that is, regardless of the magnitude of the field current, a constant duty ratio can be obtained for the position signals Pu *, Pv *, and Pw *.
[0060]
FIG. 7 is a diagram for explaining the relationship between the magnitude of the detected magnetic flux and the position signal when the conversion processing is performed in the signal processing unit shown in FIG.
[0061]
Referring to FIG. 7, the vertical axis indicates the magnitudes of signals ΔHu-v, ΔHv-w, and ΔHw-u described above, and the horizontal axis indicates the phase (electrical angle) of the magnetic flux. The signals ΔHu-v1, ΔHv-w1, and ΔHw-u1 indicate signal changes when the field current is large and the magnetic fluxes Hu, Hv, Hw detected by the magnetic sensor 20 are large, and the signals ΔHu-v2, ΔHv-w2, ΔHw -U2 indicates a signal change when the field current is small and the detected magnetic fluxes Hu, Hv, Hw detected by the magnetic sensor 20 are small.
[0062]
As shown in FIG. 7, regardless of the magnitude of the detected magnetic fluxes Hu, Hv, Hw, the time Ton (Pu *) during which the position signal Pu * is turned on is equal. The same applies to the position signals Pv * and Pw *. Therefore, in the field winding type rotating machine 1 in which the magnitude of the detected magnetic flux differs depending on the magnitude of the field current, the position signal Pu * used to generate the drive signals Dr1 to Dr6 for driving the rotating machine 1. , Pv *, Pw * become constant, and as a result, stable control performance is obtained, and there is no problem that the position signal does not turn on when the detected magnetic flux is small as in the related art.
[0063]
Further, by taking the difference between the detected magnetic fluxes Hu, Hv, and Hw, a change in the ambient temperature due to the heat generated by the coil from the rotor 2 and the stator 6 and other disturbances commonly received by the Hall elements 20a to 20c are canceled. Therefore, the influence of such disturbance is eliminated, and the position detection device 104 that is robust against disturbance is realized.
[0064]
FIG. 8 is a timing chart of main signals in the rotating machine control device 100 shown in FIG.
[0065]
Referring to FIG. 8, as described above, the position detection device 104 changes the electric angle regardless of the level of the leakage magnetic fluxes Hu, Hv, and Hw detected by the Hall elements 20a to 20c, respectively. The position signals Pu *, Pv *, and Pw * having a constant duty ratio that become H level in the range of 0 to 180 degrees, 120 to 300 degrees, and electrical angles of 0 to 60 degrees and 240 to 360 degrees are sent to the control device 106. Output.
[0066]
For comparison, the position signals Pu, Pv, Pw in the case where the field current in the rotor 2 is small and the leakage magnetic flux H is correspondingly small and the above-described processing by the signal processing unit 112 is not performed. Is shown. In this case, the on-duty ratio of each of the position signals Pu, Pv, Pw decreases, and the control accuracy of the rotating machine 1 deteriorates.
[0067]
Then, the control device 106 which has received the position signals Pu *, Pv *, Pw * from the position detection device 104 generates the received position signals Pu *, Pv *, Pw * as drive signals Dr1, Dr2, Dr3, respectively. Also, inverted signals of the position signals Pu *, Pv *, Pw * are generated as drive signals Dr4, Dr5, Dr6, respectively.
[0068]
That is, the drive signal Dr1 is a signal that turns on the MOS transistor Tr1 when the electrical angle is in the range of 0 to 180 degrees, and the drive signal Dr2 is a signal that turns on the MOS transistor Tr2 when the electrical angle is in the range of 120 to 300 degrees. The drive signal Dr3 is a signal that turns on the MOS transistor Tr3 when the electrical angle is in the range of 0 to 60 degrees and 240 to 360 degrees.
[0069]
The drive signal Dr4 is a signal for turning on the MOS transistor Tr4 when the electrical angle is in the range of 180 to 360 degrees, and the drive signal Dr5 is a signal for turning on the MOS transistor Tr5 when the electrical angle is in the range of 0 to 120 degrees and 300 to 360 degrees. And the drive signal Dr6 is a signal for turning on the MOS transistor Tr6 when the electrical angle is in the range of 60 to 240 degrees.
[0070]
As a result, although not shown, the phase voltages Vu, Vv, Vw applied to the respective phases of the rotating machine 1 and the phase currents Iu, Iv, Iw flowing through the respective phases are determined by a predetermined value without depending on the magnitude of the detected magnetic flux. It changes accurately with the electrical angle, and the operation of the rotating machine 1 is stabilized.
[0071]
The drive signals Dr1 to Dr6 drive the MOS transistors Tr1 to Tr6 so that the electric current flows in each phase of the rotating machine 1 in an electric angle range of 180 degrees. This is called a rectangular wave conduction method.
[0072]
The rotating plate 18 has a radial shape in order to provide a magnetic flux density corresponding to the field pole. However, the rotating plate 18 is not limited to such a shape, and has a radial output. What is necessary is just to be able to give the intensity of the magnetic flux density corresponding to the field pole to the generated magnetic flux. For example, materials having different magnetic permeability may be alternately arranged in the rotation direction of the disk.
[0073]
As described above, according to this embodiment, the difference between the detected magnetic fluxes corresponding to each phase is calculated, and the position signal of the rotating machine is generated based on the signal obtained by the calculation. Regardless of the magnitude, a position signal having a constant duty ratio can be obtained. As a result, stable rotating machine performance can be obtained without being affected by the magnitude of the field current.
[0074]
Further, since the position signal is obtained even when the detected magnetic flux is small, the position detectable range with respect to the magnitude of the field current is expanded, and the stop position of the rotating machine can be detected.
[0075]
Further, the output difference between the sensors (Hall elements) corresponding to each phase is calculated, and the position signal is generated based on the calculation result. Therefore, disturbances commonly received by the sensors, for example, the coils of the rotor and the stator. The influence of signal offset due to a change in ambient temperature due to heat generation can be eliminated. As a result, a rotational position detection device that is robust against disturbance is realized.
[0076]
Further, the rotating machine further includes a rotating plate at an end of the shaft, and a leakage magnetic flux flowing through the shaft and the rotating plate is detected by a magnetic sensor arranged close to the rotating plate. Can be arranged at a position remote from the rotor and the stator. Therefore, the magnetic sensor is not affected by the heat generated by the coils of the rotor and the stator, or by the disturbance magnetic field generated from the stator winding. As a result, highly accurate position detection is realized.
[0077]
In addition, since the magnetic sensor is disposed at a position where the magnetic flux leakage is maximized between the rotating plate and the stator, the magnetic flux can be effectively utilized, and from this point, the magnetic sensor is robust against disturbance. Become.
[0078]
Further, since the leakage magnetic flux inevitably generated from the rotor is used as the detected magnetic flux, it is not necessary to remodel the rotor by incorporating a magnetic piece into the rotor or changing the winding shape of the field coil. As a result, the volume of the rotor does not increase, and the manufacturing cost can be reduced.
[0079]
In the above-described embodiment, as described in the above-described effects, in order to realize a low-cost rotating machine, the leakage magnetic flux generated by the rotor 2 is detected by the magnetic detecting unit including the rotating plate 18 and the magnetic sensor 20. The detection is performed by 110, but the rotating machine is not limited to such. In other words, even when a magnetic detection element such as a Hall element is arranged close to the rotor and the magnetic flux generated from the rotor is directly detected by the magnetic detection element, the magnetic detection element consists of the difference between the detected magnetic fluxes corresponding to each phase. A method of generating a position signal based on a signal has a similar effect.
[0080]
In particular, when the magnetic detecting element is arranged close to the rotor or the stator and receives a large disturbance due to the heat generated by the coil, the disturbance is eliminated to a considerable extent, and there is no need to perform sophisticated and complicated disturbance correction calculation.
[0081]
In the above-described embodiment, the rotating machine may be a synchronous motor that generates torque or a synchronous generator that generates voltage. That is, in any case, a field current is caused to flow through a field coil in the rotor, thereby generating a magnetic flux, and the rotational position of the rotor can be detected using the magnetic flux.
[0082]
The rotating machine according to the above-described embodiment is mounted on, for example, a hybrid vehicle and can be used as a drive motor or a generator thereof. A hybrid vehicle is a vehicle that uses, in addition to a conventional engine, a DC power supply, an inverter, and a motor driven by the inverter as power sources.
[0083]
In a hybrid vehicle, a DC voltage from a DC power supply is converted into an AC voltage by an inverter, and power is obtained by rotating a motor using the converted AC voltage. The motor is connected to the engine and converts the torque of the crankshaft of the engine into electric energy during normal running of the hybrid vehicle, and converts the torque of the drive wheels during regenerative braking of the hybrid vehicle into the crankshaft of the engine. It receives via a shaft and converts the received rotational force into electrical energy.
[0084]
That is, the motor mounted on the hybrid vehicle functions as an electric motor and a generator, and as described above, can be used for any of the electric motor and the generator. For example, when the field weakening control for reducing the field current is performed in order to secure the motor speed, the rotating machine control device according to the present invention enables highly accurate motor control.
[0085]
Also, unlike a hybrid vehicle, the motor is not used as a driving power source, but when the vehicle stops at a red light at an intersection, etc., the engine is stopped and the engine is automatically started at the timing to start moving. The rotating machine of the present invention can also be used as a motor for starting the engine in the (engine automatic stop / start system).
[0086]
In the above-described embodiment, the position detection device 104 generates the position signals Pu *, Pv *, and Pw * by the signal processing unit 112 and outputs the signals to the control device 106. May output voltage signals (analog signals) corresponding to the magnitudes of the detected magnetic fluxes Hu, Hv, Hw to the control device 106, and the control device 106 may generate the position signals Pu *, Pv *, Pw *. .
[0087]
The energization system of the control device 106 in the rotating machine control device 100 is a 180-degree rectangular wave energization system, but the energization system called a 120-degree rectangular wave energization system having a higher current utilization rate than the 180-degree rectangular wave energization system. It may be controlled. Note that the 180-degree rectangular wave energization method is a control method with a higher voltage utilization rate than the 120-degree rectangular wave energization method.
[0088]
Further, although it has been described that inverter 102 receives a DC voltage from DC power supply B, in the present invention, inverter 102 may receive a DC voltage obtained by boosting a DC voltage from the DC power supply.
[0089]
That is, a DC power supply B1 that outputs a DC voltage whose voltage level is lower than the DC voltage output by the DC power supply B and a boost converter are provided instead of the DC power supply B. DC power supply B1 outputs a DC voltage to a boost converter. Then, the boost converter boosts the DC voltage and supplies it to the capacitor C1.
[0090]
Further, in the above description, the inverter 106 is described as being configured by a MOS transistor, but may be an NPN transistor instead.
[0091]
The embodiments disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description of the embodiments, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.
[0092]
【The invention's effect】
According to the present invention, the difference between the detected magnetic fluxes corresponding to the respective phases is calculated, and the position signal of the rotating machine is generated based on the signal obtained by the calculation. Is obtained.
[0093]
Further, since a position signal can be obtained even when the detected magnetic flux is small, the position detectable range for the magnitude of the field current is expanded. It is also possible to detect the stop position of the rotating machine.
[0094]
Further, since the difference between the detection signals corresponding to each phase output from the magnetic detection unit is calculated and the position signal is generated based on the calculation result, it is possible to eliminate the influence of the disturbance received by the magnetic detection unit. . As a result, a rotational position detection device that is robust against disturbance is realized.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating a configuration of a rotating machine according to an embodiment.
FIG. 2 is a cross-sectional view perpendicular to the rotation axis of the rotation plate shown in FIG.
FIG. 3 is a diagram illustrating a configuration of a rotor in the rotating machine according to the present invention.
FIG. 4 is a schematic block diagram of a rotating machine control device for controlling the rotating machine shown in FIG. 1;
5 is a layout view of the magnetic sensor shown in FIG. 1 in a direction perpendicular to a rotation axis.
6 is a functional block diagram functionally illustrating the position detection device shown in FIG.
7 is a diagram for explaining a relationship between a magnitude of a detected magnetic flux and a position signal when a conversion process is performed in the signal processing unit shown in FIG. 6;
8 is a timing chart of main signals in the rotating machine control device shown in FIG.
FIG. 9 is a diagram for explaining a relationship between a magnitude of a detected magnetic flux and a position signal in the three-phase AC rotating machine.
[Explanation of symbols]
1 rotating machine, 2 rotors, 2a and 2b members, 4 field coils, 6 stators, 8 shafts, 10, 12 bearings, 14 brushes, 16 pulleys, 18 rotating plates, 20 magnetic sensors, 20a to 20c Hall elements, 100 rotations Machine control device, 102 inverter, 104 position detection device, 106 control device, 110 magnetic detection unit, 112 signal processing unit, B DC power supply, C1 capacitor, Tr1 to Tr6 MOS transistor, D1 to D6 diode, H leakage magnetic flux.

Claims (7)

A rotation position detection device for a rotating machine including a field coil, and a rotor having a field pole formed by flowing a field current through the field coil,
A magnetic flux generated by the field coil and indicating the position of the field pole is detected, and a first plurality of signals at a level corresponding to the magnitude of the detected magnetic flux are output corresponding to a plurality of phases. A magnetic detection unit,
Receiving the first plurality of signals, calculating a level difference between signals corresponding to adjacent phases in the first plurality of signals, and converting the second plurality of signals obtained by the calculation to the position of the rotor; And a signal processing unit that outputs the signal as a signal. The rotation position detection device for a rotating machine according to claim 1, wherein the signal processing unit outputs the position signal as a digital signal having a constant duty ratio. The signal processing unit,
Outputting the corresponding position signal at a first logic level when the level difference is greater than 0;
The rotational position detecting device for a rotating machine according to claim 2, wherein when the level difference is equal to or less than 0, a corresponding position signal is output at a second logical level obtained by inverting the first logical level. The magnetic detector,
A magnetic pole that receives a first leakage magnetic flux generated by the field coil via a member different from the rotor and generates a second leakage magnetic flux indicating the position of the field pole based on the first leakage magnetic flux A generating unit;
A plurality of magnetic detection elements for detecting the second leakage magnetic flux output from the magnetic pole generation unit and outputting the first plurality of signals at a level corresponding to the magnitude of the second leakage magnetic flux; The rotation position detecting device for a rotating machine according to any one of claims 1 to 3, which includes: The magnetic pole generation unit has a radial shape corresponding to the field pole, and applies the strength of a magnetic flux density corresponding to the field pole to the first leak magnetic flux to radially change the second leak magnetic flux. The rotation position detecting device for a rotating machine according to claim 4, which outputs the rotation position. The rotational position detecting device for a rotating machine according to claim 4 or 5, wherein the plurality of magnetic detection elements are arranged at intervals of an electrical angle obtained by dividing 360 degrees by the number of phases, in a rotation direction of the magnetic pole generation unit. . A rotation position detection device for a rotating machine according to any one of claims 1 to 6,
A drive circuit for driving the rotating machine,
A control circuit for controlling the drive circuit based on the position signal received from the rotational position detection device.

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