JP5545174B2 - Rotation angle detector - Google Patents

Description

  The present invention relates to a rotation angle detection device that corrects an error in rotation angle detected based on a signal output from a rotation sensor.

  A resolver tends to be used for a rotation sensor that detects the rotation angle (electrical angle) of an object from the viewpoint of emphasizing durability and reliability. The resolver includes a stator (stator), a rotor (rotor), an excitation coil, and a detection coil. As a conventional rotation angle detection device using a resolver, an example of a technique for correcting a rotation angle error for each section is disclosed (see, for example, Patent Document 1).

  In the technique of Patent Document 1, the error correction unit corrects the detected angle error for each angle section obtained by dividing one rotation period of the rotor at equal intervals. More specifically, an error map indicating the correspondence between the detected angle and the error is created for each of n angle sections, and the correction amount calculation unit uses the error map corresponding to each angle section to generate an error (that is, a correction amount). And the correction angle calculation unit corrects the error of the detection angle.

JP 2010-096708 A

  However, in the rotational speed feedback control in which the rotational speed (also referred to as “rotational speed”, hereinafter the same) is calculated based on the rotational angle of the rotor, and the calculated rotational speed is controlled to become the commanded rotational speed. It was found that the rotational speed fluctuates when the rotational speed is low.

  The case where the rotational speed is low corresponds to, for example, a state in which the motor or the like is substantially stopped (stationary), or a state in which the motor is rotating at a low speed. In the former state, the rotation shaft of the motor or the like may rotate carelessly due to some factor (for example, external noise), and if a change in the rotation angle of the rotor is detected as a result of this rotation, the error correction means operates. Will be increased. In the latter state, the rotation shaft of the motor or the like may be rotated with low-speed rotation, and if a change in the rotation angle of the rotor is detected with this fluctuation, the rotation is increased by the action of the error correction means. . In any case, since the error correction means corrects the error using the error map, the rotation angle changes greatly. When the rotation speed calculated based on the corrected rotation angle is feedback-controlled, an unnecessary torque is generated in the motor or the like and the rotation speed fluctuates.

  The present invention has been made in view of these points, and an object of the present invention is to provide a rotation angle detection device that can suppress fluctuations in the rotation speed when the rotation speed is low.

The invention according to claim 1, which has been made in order to solve the above problem, holds an angle acquisition unit that detects a rotation angle of an electric motor, and a detection error with respect to an ideal angle of a detection angle output by the angle acquisition unit as a correction amount. A rotation angle detecting device comprising: a recording unit that performs correction; and a correction execution unit that corrects a detection angle based on the correction amount, wherein the correction execution unit changes the correction amount according to a target rotation speed. Correction amount changing means is provided .

According to this configuration, the correction amount changing unit changes the correction amount according to the target rotation speed, and the correction execution unit corrects the error of the rotation angle. Therefore, the target rotation speed is low (the rotation speed is 0). ), The fluctuation of the rotational speed can be suppressed.

  The “rotation sensor” is arbitrary as long as it can detect the rotation of the rotating member, convert it into an electrical signal, and output it. For example, a resolver, a rotary encoder, a gyroscope, a GMR (Giant Magnetoresistance Revolution) rotation sensor, and the like are applicable. The “rotating member” is arbitrary as long as it is a member to be subjected to rotation control, and it does not matter whether it is a part of the device. For example, a shaft (including a main shaft of a rotating machine), a shaft, a gear (including a gear mechanism), and the like are applicable. When the rotor of the resolver is a “rotating member”, it includes a rotor having a shaft angle multiplier n (n is an integer of 2 or more). The “error correction means” is arbitrary as long as it is a means for correcting the detection angle. For example, a map (including a data table) for storing a correction amount with respect to an ideal angle, which will be described later, and a function expression approximated to a change in the correction amount are applicable. The values of “detected rotational speed” and “command rotational speed” may be positive or negative. For example, when a positive value is defined as positive rotation, a negative value means reverse rotation.

According to a second aspect of the present invention, when the target rotation speed is lower than a first predetermined value, the correction amount changing means is based on the correction amount held in the recording means. A low rotation correction amount calculating means for calculating a correction amount actually used for correction is provided . According to this configuration, when the target rotation speed is lower than the first predetermined value , the low rotation correction amount calculation unit corrects the correction actually used for correction based on the correction amount held in the recording unit. Since the amount is calculated, when the target rotational speed is low, fluctuations in the rotational speed can be suppressed.

The invention according to claim 3 is characterized in that the low rotation correction amount calculating means calculates the actually used correction amount based on the correction amount held in the recording means and a predetermined characteristic line. And According to this configuration, when the rotational speed is low, fluctuations in the rotational speed can be suppressed.

According to a fourth aspect of the present invention, the characteristic line has a change ratio in a range where the target rotation speed is lower than a second predetermined value as a predetermined value . According to this configuration, when the rotational speed is low, fluctuations in the rotational speed can be suppressed.

According to a fifth aspect of the present invention, the characteristic line has a change ratio of 0 in a range where the target rotational speed is lower than a second predetermined value . According to this configuration, when the rotational speed is low, fluctuations in the rotational speed can be suppressed.

It is a figure which shows typically the structural example of the power conversion system which controls a rotary electric machine. It is a figure which shows the structural example of a control apparatus typically. It is a figure explaining the process of calculating | requiring the correction amount of a map. It is a graph which shows the relationship between a correction amount and a detection angle. It is a flowchart which shows the example of a procedure of a rotation angle correction process. It is a flowchart which shows the example of a procedure of a rotation angle correction process. It is a flowchart which shows the example of a procedure of a rotation angle correction process. It is a graph which shows the relationship between a rotation speed and a characteristic line. It is a graph which shows the relationship between a correction amount and a detection angle.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. Unless otherwise specified, “connect” means electrical connection. Each figure shows elements necessary for explaining the present invention, and does not show all actual elements. When referring to directions such as up, down, left and right, the description in the drawings is used as a reference. In the following embodiments, for the sake of simplicity, a rotation angle for detecting rotation (rotation angle, rotation speed, etc.) applied to a rotation shaft (for example, a main shaft) of a rotating electrical machine provided in a transport device (particularly a vehicle of a car). A description will be given on the assumption of the detection device.

[Embodiment 1]
The first embodiment is an example of determining whether to perform correction based on the detected rotation speed, and will be described with reference to FIGS. FIG. 1 schematically shows a configuration example of a power conversion system that controls a rotating electrical machine. FIG. 2 schematically shows a configuration example of the control device. FIG. 3 shows a process of obtaining the map correction amount based on the ideal angle and the detected angle. FIG. 4 is a graph showing the relationship between the correction amount and the detection angle. FIG. 5 is a flowchart showing a procedure example of the rotation angle correction process.

  The power conversion system shown in FIG. 1 includes a converter circuit 10, an inverter circuit 20, a control power supply circuit 50, a control device 60, and the like. The converter circuit 10 is provided as necessary, and a DC voltage (voltage value V1; for example, 300 [V] or the like) supplied from a first DC power source E1 (for example, a battery or the like) through a smoothing capacitor C1. The inverter circuit 20 has a function of converting to a DC voltage (voltage value Vdc) required for output. Since the configuration and operation of the converter circuit 10 are well known, illustration and description are omitted.

  The inverter circuit 20 has a function of converting a supplied DC voltage (voltage value Vdc; for example, 660 [V]) and outputting it to the rotating electrical machine 40. A converter circuit 10 is interposed between the first DC power supply E1 and the inverter circuit 20. A smoothing capacitor C2 is connected between the converter circuit 10 and the inverter circuit 20. Capacitor C2 has a function of reducing potential fluctuations in the output voltage value (voltage value Vdc) of converter circuit 10.

  The inverter circuit 20 includes switching elements Q1 to Q6, diodes D1 to D6, and the like. For example, IGBTs are used for the switching elements Q <b> 1 to Q <b> 6, and ON / OFF is driven according to the control signal Sp transmitted individually from the control device 60. Diodes D1-D6 are connected in parallel between the collector terminals and emitter terminals of switching elements Q1-Q6, respectively. These diodes D1 to D6 all function as freewheeling diodes. Switching elements Q1-Q3, diodes D1-D3, etc. are arranged on the upper arm side, and switching elements Q4-Q6, diodes D4-D6, etc. are arranged on the lower arm side. The common potential G1 is a common potential (same potential ground) in the inverter circuit 20, and becomes 0 [V] when connected to the ground G2. Since the common potential G1 and the ground G2 may not necessarily be the same potential, they use different graphic symbols.

  The circuit elements in the inverter circuit 20 are divided into three phases (U phase, V phase, W phase in this example) as shown by being surrounded by a one-dot chain line, and the operation is controlled for each phase by the control device 60. The U phase is composed of switching elements Q1, Q4, diodes D1, D4, and the like. The V phase includes switching elements Q2 and Q5, diodes D2 and D5, and the like. The W phase includes switching elements Q3 and Q6, diodes D3 and D6, and the like. The U-phase switching elements Q1 and Q4 are connected in series to form a half bridge. Similarly, the V-phase switching elements Q2 and Q5 and the W-phase switching elements Q3 and Q6 are connected in series to form a half bridge. Each connection point of the half bridge and the three-phase terminal of the rotating electrical machine 40 are connected for each phase by lines Ku, Kv, Kw. A U-phase current Iu flows through the line Ku, a V-phase current Iv flows through the line Kv, and a W-phase current Iu flows through the line Kw.

  The control power supply circuit 50 converts a DC voltage V2 (for example, 12 [V], etc.) supplied from the second DC power supply E2 (for example, a battery) into a voltage or current required by the converter circuit 10, the inverter circuit 20, or the like. The function to output. Since the configuration and operation of the control power supply circuit 50 are well known, illustration and description thereof are omitted. These control power supply circuit 50 and second DC power supply E2 are both connected to ground G2 and grounded.

The control device 60 corresponds to a “rotation angle detection device” and controls the operations of the converter circuit 10 and the inverter circuit 20. A configuration example of the control device 60 for realizing the present invention will be described later (see FIG. 2). A signal input by the control device 60 includes a command rotational speed N ^* and a torque command value T ^* transmitted from the ECU 70 corresponding to an external device, a current I (Iu, Iv, Iw) transmitted from the current sensor 30, and a resolver 41. There is a signal output from. The signal output from the control device 60 includes a control signal Sp transmitted to the control terminals P1 to P6 of the switching elements Q1 to Q6, a control signal transmitted to the drive circuit provided in the converter circuit 10, and the like.

  For the rotating electrical machine 40, for example, a generator motor (described as “MG” in FIG. 1) having both a power generation function and an electric function is applied. As the current sensor 30, a sensor capable of detecting each phase current (Iu, Iv, Iw) flowing through the rotating electrical machine 40 is used. For example, a magnetic proportional sensor, an electromagnetic induction sensor, a Faraday effect sensor, a current transformer sensor, and the like are applicable. The resolver 41 corresponds to a “rotation sensor” and outputs a signal (such as a SIN detection signal Ss or a COS detection signal Sc) based on an electrical angle of a rotating member (for example, a rotating shaft or a rotor) provided in the rotating electrical machine 40.

  The power conversion system described above is preferably provided in a transport device that can realize movement by driving the rotating electrical machine 40. For example, automobiles, airplanes, ships, railway vehicles, and the like correspond to the transportation equipment.

  Next, a configuration example of the control device 60 will be described with reference to FIG. The control device 60 has various functions for controlling the converter circuit 10, the inverter circuit 20, and the like. FIG. 2 shows a configuration example (that is, a partial configuration example) for realizing the present invention.

  The control device 60 shown in FIG. 2 includes a rotation speed feedback control means 61, a correction execution determination means 62, a rotation speed calculation means 63, a correction execution means 64, a recording means 65, and the like. The correction execution unit 64 corrects the error of the detection angle θd indicating the rotation angle detected based on the signal output from the resolver 41 by the error correction unit 65a. However, if the determination information J output (transmitted) from the correction execution determination means 62 described later is a content that “does not perform correction”, the error is output as it is without correcting the error of the detected angle θd.

  The number of error correction means 65a recorded in the recording means 65 may be one or plural. The error correction unit 65a is a correction amount data group for correcting the error of the detection angle θd, and corresponds to, for example, a map or a data table. When recording a plurality of recording means 65, the correction amount varies depending on the rotor shape, the rotational speed, etc. of the resolver 41. As the recording means 65, any recording medium capable of recording the error correction means 65a is used, and for example, a nonvolatile memory such as a ROM, an EEPROM, a magneto-optical disk or the like is desirable.

The rotational speed calculation means 63 calculates the detected rotational speed Ns based on the detected angle θd corrected by the correction execution means 64. The correction execution determination means 62 determines whether or not correction by the correction execution means 64 is performed based on one or both of the detected rotation speed Ns and the command rotation speed N ^* , and outputs determination information J. To do.

The rotational speed feedback control means 61 performs feedback control so that the detected rotational speed Ns becomes the command rotational speed N ^* . As surrounded by the alternate long and short dash line, the rotational speed feedback control means 61 includes an adder 61a, a torque command calculator 61b, a motor torque controller 61c, and the like. The joining unit 61a performs addition of input signals (that is, signals relating to the command rotational speed N ^* and the detected rotational speed Ns). In the example of FIG. 2, in order to form a negative feedback loop, a deviation obtained by subtracting the detected rotational speed Ns from the command rotational speed N ^* is output as the differential rotational speed Ne. The torque command calculation unit 61b calculates a torque necessary for the rotation of the rotating electrical machine 40 based on the differential rotation speed Ne and outputs it as a torque command T ^* . The motor torque control unit 61c outputs a control signal Sp necessary for driving the inverter circuit 20 based on the torque command T ^* . For example, a pulse width modulation (PWM) signal or the like is used as the control signal Sp.

Next, the error correction unit 65a recorded in the recording unit 65 will be described with reference to FIG. As shown on the left side of FIG. 3, the ideal angle θ _i is an angle at which the rotation angle indicated by the vertical axis changes ideally (that is, linearly or proportionally) as the time indicated by the horizontal axis changes. On the other hand, the actually detected detection angle θ _d is an angle that causes a non-linear change in which the rotation angle indicated by the vertical axis is not proportional to the time change indicated by the horizontal axis. To approximate the detected angle theta _d ideal angle theta _i, the error obtained by subtracting the detected angle theta _d from the ideal angle theta _i is the correction amount A _m. Characteristic line of the correction amount A _m (correction line) shown on the right side of FIG. On the right side of FIG. 3, the correction amount indicated by the vertical axis changes with the change of time indicated by the horizontal axis. Therefore, the correction amount _Am is a data group that can be shown as a characteristic line (correction line) as shown. Note that the “error value” shown in parentheses is opposite in the amount of correction and positive and negative, and is the same value in terms of absolute value.

Correction amount A _m of error correction means 65a for recording the recording unit 65 may be one or may be plural. Correction amount as a plurality of error correction means 65a _{A m} (e.g. correction amount _{A m1, A m2, A m3} , ...) to record, for example a resolver 41 shaft angle multiplier n (n is an integer of 2 or more) is formed by This includes a case where a rotor is provided or a case where error characteristics change according to the number of rotations of the rotor. An example of the former, and records the correction amount A _m corresponding to each section of the n delimited by the shaft angle multiplier. An example of the latter records the correction amount A _m corresponding to stepwise according to the number of revolutions of the rotor (for example, every 1000 [rpm] and 2000 [rpm]).

Figure 4 shows an example of the correction amount A _m of actually recorded. In FIG. 4, the change in the detection angle is shown on the horizontal axis, and the change in the correction amount is shown on the vertical axis. Time corresponds to one rotation interval. “Rotation section” usually means one rotation section (in other words, a section that actually rotates 360 degrees). However, in the case of a rotor formed with the above-described shaft angle multiplier n, it means a 1 / n rotation section. The correction amount A _m (A _m1 ) of the characteristic line indicated by the solid line corresponds to one error correction unit 65a. The characteristic line correction amount A _m (A _m1 ) indicated by the one-dot chain line and the characteristic line correction amount A _m (A _m3 ) indicated by the two-dot chain line together with the characteristic line correction amount A _m (A _m1 ) indicated by the solid line. This corresponds to a plurality of error correction means 65a.

  In the control device 60 configured as described above, an example of the procedure of the rotation angle correction process for realizing the present invention will be described with reference to FIG. This rotation angle correction process is repeatedly executed while the control device 60 is operating. In FIG. 5, steps S10 and S13 correspond to correction execution means 64, steps S11 and S14 correspond to rotation speed calculation means 63, step S12 corresponds to correction execution determination means 62, and step S15 corresponds to rotation speed feedback. It corresponds to the control means 61.

  In the rotation angle correction process shown in FIG. 5, first, the detection angle θd of the rotating electrical machine 40 is obtained based on signals (SIN detection signal Ss, COS detection signal Sc, etc.) output from the resolver 41 [step S10]. Based on the amount of change per unit time of the detected angle θd, the detected rotational speed Ns of the rotating electrical machine 40 is obtained [step S11]. Judgment information J is determined according to whether or not the detected rotational speed Ns obtained in step S11 this time (or before the previous time) is within the first rotational speed range [step S12]. That is, if the detected rotational speed Ns is within the first rotational speed range, it is determined that “correction is not performed”, and if the detected rotational speed Ns is outside the first rotational speed range, it is determined that “correction is performed”. The first rotation speed range can be arbitrarily set, and corresponds to a range from −50 [rpm] to 50 [rpm], for example. Whether the detected rotational speed Ns to be determined in step S12 is the detected rotational speed Ns obtained in step S11 this time or the detected rotational speed Ns obtained in step S11 before the previous time is the type of the rotating electrical machine 40 Set appropriately according to the control purpose.

If the detected rotational speed Ns is within the first rotational speed range (YES), if the detected angle θd is erroneously increased by correction due to some factor (for example, external noise or load fluctuation), The rotation number calculated based on the value is larger than the actual value, and the influence on the rotation number feedback control becomes relatively large. Therefore, it is determined that “correction is not performed” and correction by the error correction unit 65a is not performed, and feedback control is performed so that the detected rotational speed Ns obtained in step S11 becomes the command rotational speed N ^* [step S15]. The angle correction process is returned.

On the other hand, if the detected rotational speed Ns is outside the first rotational speed range in step S12 (NO), even if the detected angle θd of the rotating shaft of the rotating electrical machine 40 is erroneously increased, the influence on the rotational speed feedback control is small. Therefore, it is determined that “correction is performed”, and the recording unit 65 also corrects the detected angle θd obtained in step S10 by using the recorded error correcting unit 65a [step S13], and unit time of the corrected detected angle θd. The detected rotational speed Ns of the rotating electrical machine 40 is obtained based on the amount of change per hit [step S14], feedback control is performed so that the detected rotational speed Ns becomes the command rotational speed N ^* [step S15], and rotational angle correction processing is performed. To return.

According to the first embodiment described above, the following effects can be obtained. (1) A resolver 41 that outputs a signal in accordance with rotation of a rotating member (specifically, a rotating shaft or a rotor ) of the rotating electrical machine 40, and a detection angle θd (detected based on a signal output from the resolver 41) Correction execution means 64 for correcting the error of the rotation angle) by the error correction means 65a, rotation speed calculation means 63 for calculating the detected rotation speed Ns based on the detected angle θd corrected by the correction execution means 64, and detected rotation Based on the rotational speed feedback control means 61 that performs feedback control so that the number Ns becomes the commanded rotational speed N ^*, and based on one or both of the detected rotational speed Ns and the commanded rotational speed N ^* , A correction execution determination unit 62 that determines whether or not to perform correction by the correction execution unit 64 is provided (see FIG. 2). The correction execution means 64 is configured to correct the error of the detected angle θd only when it is determined that the correction execution determination means 62 performs correction (see steps S12 and S13 in FIG. 5). According to this configuration, the correction execution unit 64 corrects the error of the detection angle θd only when it is determined that the correction execution determination unit 62 performs correction. Conversely, when the rotational speed is low, the error in the detected angle θd is not corrected, so that fluctuations in the rotational speed can be suppressed.

(2) error correction means 65a has a map for storing a correction amount A _m with respect to an ideal angle indicating the rotational angle of ideally varies with a change in time (see Figure 2, Figure 3). Correction execution unit 64 uses the correction amount A _m of the map, and configured to correct an error of the detected angle [theta] d (rotation angle) (see step S13 in FIG. 5). According to this configuration, since the correcting an error of the detected angle θd by using the correction amount A _m of the map, can be realized the invention with a simple structure.

(3) The correction execution determination means 62 determines that the correction execution means 64 does not perform correction when the detected rotation speed Ns is within the first rotation speed range including 0 (YES in step S13 in FIG. 5). When it is outside the first rotation speed range, it is determined that correction by the correction execution means 64 is performed (NO in step S13 of FIG. 5). According to this configuration, in the low-speed rotation state or the rotation stop state, it is possible to prevent the correction execution means 64 from increasing the rotation number by mistake, so that the rotation number at the low rotation number can be stabilized. The “first rotation speed range” can be set arbitrarily except that the range includes 0, and the rotation speed varies with the influence of the correction by the correction execution means 64. Includes a range of numbers.

[Embodiment 2]
The second embodiment is an example of determining whether to perform correction based on not only the detected rotation speed but also the command rotation speed, and will be described with reference to FIG. FIG. 6 is a flowchart showing a procedure example of the rotation angle correction process in place of FIG. The configuration and the like of the power conversion system are the same as those in the first embodiment, and in the second embodiment, points different from the first embodiment will be described in order to simplify the illustration and description. Therefore, the same elements as those used in Embodiment 1 are denoted by the same reference numerals, and description thereof is omitted.

  The rotation angle correction process shown in FIG. 6 is different from the rotation angle correction process shown in FIG. 5 in that step S16 is added. This step S16 corresponds to the correction execution determining means 62 together with step S12.

Step S16 is executed when the detected rotational speed Ns obtained in step S11 is within the first rotational speed range (YES), and the judgment information J is determined according to whether the command rotational speed N ^* is within the second rotational speed range. decide. That is, if the command rotation speed N ^* is within the second rotation speed range, it is determined that “correction is not performed”, and if the detected rotation speed Ns is outside the first rotation speed range, it is determined that “correction is performed”. The second rotation speed range can be arbitrarily set, and corresponds to a range from −50 [rpm] to 50 [rpm], for example. In this example, the second rotation speed range is set to the same range as the first rotation speed range, but may be set to a different range depending on the type of the rotating electrical machine 40, the type of the rotor of the resolver 41, and the like.

The rotation angle correction process shown in FIG. 6 by step S16 described above is performed only when the detected rotation speed Ns is within the first rotation speed range and the command rotation speed N ^* is within the second rotation speed range. Determination information J for determining “no correction” is determined.

According to the second embodiment described above, the following effects can be obtained. The effects corresponding to (1) to (3) are the same as in the first embodiment.

(4) The correction execution determination means 62 determines that the correction execution means 64 does not perform correction when the command rotation speed N ^* is within the second rotation speed range including 0 (YES in step S16 in FIG. 5). When it is out of the second rotation speed range, it is determined that correction by the correction execution means 64 is performed (NO in step S16 in FIG. 5). According to this configuration, when the command rotational speed N ^* is within the second rotational speed range including 0, the correction execution unit 64 does not correct the error of the detected angle θd (rotational angle). In the low-speed rotation state or the rotation stop state, the correction execution means 64 can prevent the rotation number from being erroneously increased, so that the rotation number at a low rotation number can be stabilized.

[Embodiment 3]
The third embodiment is an example in which the correction amount is suppressed when the rotational speed (detected rotational speed or command rotational speed) is low, and will be described with reference to FIGS. FIG. 7 is a flowchart showing a procedure example of rotation angle correction processing instead of FIGS. 5 and 6. FIG. 8 is a graph showing the relationship between the rotational speed and the characteristic line. FIG. 9 is a graph showing the relationship between the correction amount and the detection angle. The configuration and the like of the power conversion system are the same as those in the first and second embodiments, and in order to simplify the illustration and explanation, the third embodiment will be described with respect to differences from the first and second embodiments. Therefore, the same elements as those used in the first and second embodiments are denoted by the same reference numerals and description thereof is omitted.

The rotation angle correction process shown in FIG. 7 differs from the rotation angle correction process shown in FIGS. 5 and 6 in the following two points. First, step S17 is added. This step S17 corresponds to the correction execution means 64 together with step S12. Second, whether the detected rotational speed Ns is within the first rotational speed range in step S12 (YES), or when the command rotational speed N ^* is within the second rotational speed range in step S16 indicated by a two-dot chain line (YES) is that steps S14 and S15 are executed after step S17 is executed.

  In step S17, when the detected rotation speed Ns is within the third rotation speed range, the error correction means 65a is changed according to the correction characteristic line, and the detection angle θd obtained in step S10 is corrected. The third rotation speed range may be set within the first rotation speed range in step S12 or the same range as the second rotation speed range in step S16, or may be set in a different range. A method of changing the error correction means 65a in accordance with the correction characteristic line will be described with reference to FIGS.

  FIG. 8 shows an example of correction characteristic lines L1 and L2 in which the vertical axis is the correction amount change ratio R and the horizontal axis is the detected rotation speed Ns. In this example, the change ratio R is a range from 0 to 1, and the third rotation speed range is a range from 0 to N3 (for example, 100 [rpm]). In the correction characteristic line L1 indicated by the solid line, the change ratio R changes linearly (proportionally) in the range where the detected rotational speed Ns is from Na to N3. However, the range where the detected rotational speed Ns is from 0 to Na is a characteristic in which the change ratio R is 0. The correction characteristic line L2 indicated by the alternate long and short dash line has a change ratio R of 0 when the detected rotational speed Ns is 0, and the change ratio R changes in a curved shape. Note that the correction characteristic lines L1 and L2 shown in FIG. 8 are merely examples, and changes as characteristic lines may be set in any manner. The setting of the third rotation speed range (N3) is also arbitrary.

For correction characteristic lines L1, L2, which has been described above, the detected rotational speed Ns is described modified method of the correction amount A _m when a rotation speed Nb. In FIG. 8, it can be seen that the correction characteristic line L1 has a change ratio Ra, and the correction characteristic line L2 has a change ratio Rb (Rb> Ra). Changing the correction amount A _m shown by the solid line in FIG. 4, is shown in FIG. For ease of comparison 9, the correction amount A _m of FIG. 4 shows a two-dot chain line indicates the correction amount A _ma has been changed in accordance with changing ratio Ra by the solid line, the correction amount A _mb changing in accordance with the changed ratio Rb Shown with a dashed line. Compared to the original correction amount A _m As apparent, the correction amount A _ma, but overall change A _mb is the same as the original correction amount A _m, an amount to be corrected is reduced. Even if the detection angle θd is erroneously increased by correction due to some factor (for example, external noise or load fluctuation), the correction amount itself is reduced, so that the change in the detection angle θd after correction is suppressed.

8 and 9 described above show an example in which the correction amount _Am is changed in relation to the detected rotation speed Ns. Instead of this configuration, the horizontal axis command rotational speed N ^*, it may be configured to change the correction amount A _m in relation to the command rotational speed N ^*. Or it is good also as a structure which changes correction amount _Am by the relationship between detected rotation speed Ns and instruction | command rotation speed N ^* like a three-dimensional map. In any configuration, since the correction amount itself is reduced, a change in the detected angle θd after correction is suppressed.

According to the third embodiment described above, the following effects can be obtained. The effects corresponding to (1) and (2) are the same as in the first embodiment.

(5) When one or both of the detected rotational speed Ns and the command rotational speed N ^* are within the third rotational speed range including 0, the correction execution means 64 falls within the third rotational speed range. The detection angle θd (rotation angle) is corrected in accordance with the specified correction characteristic line (see step S17 in FIG. 7, FIG. 8, and FIG. 9). According to this configuration, when the rotation speed is within the third rotation speed range including 0, the correction execution unit 64 corrects the error of the detection angle θd according to the correction characteristic line. Therefore, when the rotational speed is low, fluctuations in the rotational speed can be suppressed. Depending on the setting of the correction characteristic line, even when extremely slow rotation is required, the correction is appropriately performed. Therefore, it is possible to perform the rotation control while suppressing the fluctuation of the rotation speed.

[Other Embodiments]
Although the form for implementing this invention was demonstrated according to Embodiment 1-3 in the above, this invention is not limited to the said form at all. In other words, various forms can be implemented without departing from the scope of the present invention. For example, the following forms may be realized.

  In Embodiments 1 to 3 described above, the rotating shaft, rotor, or the like of the rotating electrical machine 40 is applied as the rotating member (see FIGS. 1 and 2). Instead of (or in addition to) this form, other rotating members may be applied. Other rotating members include, for example, rotating shafts and rotors of rotating electrical machines other than generator motors, shafts (for example, crankshafts and drive shafts) used in vehicles, gears (including gear mechanisms), steering rods (or torsion) Bar), other rotatable members such as a steering shaft, and the like. Even if it is another rotating member, if the resolver 41 can be attached, the effect similar to Embodiment 1-3 is obtained.

  In the above-described first to third embodiments, the resolver 41 is applied as a rotation sensor (see FIGS. 1 and 2). Instead of this form, another rotation sensor may be applied. Examples of other rotation sensors include a rotary encoder, a gyroscope, and a GMR rotation sensor. Even if it is another rotation sensor, since it correct | amends based on a correction characteristic line, it does not correct | amend at the time of the low speed rotation containing 0, The effect similar to Embodiment 1-3 is acquired.

  In Embodiments 1 to 3 described above, a map is applied as the error correction means 65a (see FIGS. 3 and 4). Instead of this form, other correction means capable of correcting the detection angle θd may be applied. As other correction means, for example, a data table, a function in which correction characteristic lines shown in FIGS. Since the detection angle θd can be corrected even by other correction means, the same effects as those of the first to third embodiments can be obtained.

DESCRIPTION OF SYMBOLS 10 Converter circuit 20 Inverter circuit 30 Current sensor 40 Rotating electric machine 41 Resolver (rotation sensor)
50 control power circuit 60 control device (rotation angle detection device)
61 Rotational Speed Feedback Control Unit 61a Addition Unit 61b Torque Command Calculation Unit 61c Motor Torque Control Unit 62 Correction Execution Determination Unit 63 Rotation Number Calculation Unit 64 Correction Execution Unit 65 Recording Unit 65a Error Correction Unit 70 ECU (External Device)

Claims (5)

Angle acquisition means for detecting the rotation angle of the electric motor;
A recording unit that holds, as a correction amount, a detection error with respect to an ideal angle of a detection angle output by the angle acquisition unit;
A rotation angle detection device having correction execution means for correcting the detection angle based on the correction amount,
The rotation angle detection apparatus according to claim 1, wherein the correction execution means includes correction amount changing means for changing the correction amount in accordance with a target rotation speed . The correction amount changing unit calculates a correction amount actually used for the correction based on the correction amount held in the recording unit when the target rotation speed is lower than a first predetermined value. The rotation angle detection device according to claim 1, further comprising: a low rotation correction amount calculating means . 3. The rotation according to claim 2 , wherein the low rotation correction amount calculation unit calculates the correction amount actually used based on the correction amount held in the recording unit and a predetermined characteristic line. Angle detection device. The rotation angle detection device according to claim 3, wherein the characteristic line has a change ratio in a range where the target rotation speed is lower than a second predetermined value as a predetermined value . 5. The rotation angle detection device according to claim 4, wherein the characteristic line sets a change ratio in a range in which the target rotation speed is lower than a second predetermined value to 0. 6 .

Images