JP2023000734A - Rotation position correction device, motor driving system, and method for correcting rotation position - Google Patents

Abstract

To provide a rotation position correction device, a motor driving system, and a method for correcting a rotation position that can make the result of detection of the angle of a shaft by a resolver less dependent on temperatures.SOLUTION: The rotation position correction device has a detection value correction unit. A motor detects the angle of a shaft by a resolver. The detection value correction unit corrects the angel detected value of the resolver corresponding to the temperature of the resolver, on the basis of the estimated value or the detected value of the temperature of the resolver changing according to the output of the motor.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD Embodiments of the present invention relate to a rotational position correction device, a motor drive system, and a rotational position correction method.

A resolver is used to detect the angle of a rotating body connected to the shaft by detecting the angle (rotational position) of the shaft. Depending on the ambient temperature of the resolver, the accuracy of the angle detection result may be degraded.

JP 2007-263943 A

SUMMARY OF THE INVENTION It is an object of the present invention to provide a rotational position correcting device, a motor drive system, and a rotational position correcting method that can reduce the temperature dependence of the shaft angle detection result by a resolver.

A rotational position correction device according to an embodiment includes a detection value correction unit. A resolver detects the angle of the shaft of the motor. The detection value correction unit corrects the angle detection value of the resolver corresponding to the temperature based on the estimated value or the detection value of the temperature of the resolver that changes according to the output of the motor.

1 is a schematic configuration diagram of a motor drive system according to a first embodiment; FIG. FIG. 4 is a diagram showing the relationship between the magnitude of the output of the motor drive system of the embodiment and the saturation temperature; The figure which shows the relationship of the time which the motor drive system of embodiment was operate|moving, and temperature. FIG. 4 is a diagram for explaining temperature changes accompanying changes in the operating state of the motor drive system according to the embodiment; FIG. 4 is a diagram for explaining an angle detection value including an ambient temperature-dependent error according to the embodiment; FIG. 4 is a diagram for explaining the relationship between the ambient temperature and the error in the detected angle value according to the embodiment; The schematic block diagram of the motor drive system of 2nd Embodiment. The schematic block diagram of the motor drive system of 3rd Embodiment.

A rotational position correction device, a motor drive system, and a rotational position correction method according to embodiments will be described below with reference to the drawings. It should be noted that the drawings are schematic or conceptual, and the distribution of functions of each part is not necessarily the same as the actual one.

In the following description, the same reference numerals are given to components having the same or similar functions. Duplicate descriptions of those configurations may be omitted.
In the embodiments, "connected" includes electrically connected. "Based on XX" means "based at least on XX" and may include based on other elements in addition to XX. "Based on XX" is not limited to the case where XX is used directly, but can also include the case where XX is calculated or processed. "XX or YY" is not limited to either one of XX and YY, but may include both XX and YY. This is also the case when there are three or more selective elements. "XX" and "YY" are arbitrary elements (for example, arbitrary information). An “inverter” is a power converter that outputs alternating current, and includes, for example, a DC/AC converter. A "motor" is a rotating electric machine such as an induction motor driven by AC power. "Motor rotation speed" is sometimes simply referred to as "motor speed".

A "measured value of current" used in the following description refers to an actual measured value of current, an index value indicating the actual magnitude of current, or an estimated value indicating the magnitude of current.

(First embodiment)
FIG. 1 is a block diagram illustrating a motor drive system 1 including a rotational position correction device according to the first embodiment. For example, the motor drive system 1 comprises a motor speed controller 10 . The motor speed control device 10 is an example of a rotational position correction device. The motor drive system 1 may further include a motor 2 (marked as M in FIG. 1) and a resolver 2A (marked as SS in FIG. 1).

A motor speed controller 10 is connected to the motor 2 and resolver 2A. The motor speed control device 10 controls the speed of the motor 2 so that the actual speed of the motor 2 detected by the resolver 2A matches the desired speed command value ω ^* .

The motor 2 has a plurality of windings, and each winding is connected to the output of an inverter 30, which will be described later. Inverter 30 is an example of a power converter. For example, the inverter 30 converts DC power supplied from a DC power supply 20 (denoted as DC in the drawing) to drive the motor 2 . For example, when alternating current from the inverter 30 flows through each winding, the motor 2 rotates due to electromagnetic action. For example, the shaft of the resolver 2A is mechanically connected to the shaft of the motor 2 by a method such as flange coupling, and the shaft of the resolver 2A rotates in conjunction with the rotation of the shaft of the motor 2. FIG.

The resolver 2A generates an AC signal according to the position of its own shaft. For example, the resolver 2A detects the magnetic flux excited by the current of the primary winding through the secondary winding. The voltage or current induced in the secondary winding becomes an AC signal containing phase information according to the angular difference between the direction of the magnetic flux being energized and the direction of the secondary winding. The resolver 2A generates the AC signal as a detection signal of the position of its own shaft. For example, the primary winding of resolver 2A is fixed to its housing. The housing of the resolver 2A is fixed to a common base with the motor 2 or the housing of the motor 2, for example. Therefore, the positional relationship of each part may change within the allowable range due to the difference in temperature of the resolver 2A.

Note that the resolver 2A of the embodiment includes a signal converter therein. The signal converter generates an index value indicating the angle of the shaft of the resolver 2A, that is, an index value indicating the angle of the shaft of the motor 2 (referred to as the detected angle value θe2), based on the AC signal corresponding to the position of its own shaft. Generate. In other words, this resolver 2A generates and outputs an angle detection value θe2 corresponding to the detection result of the shaft angle of the motor 2 . A signal converter contains electronic circuitry for signal processing. Therefore, the output signal may contain an offset that depends on the ambient temperature. In the following explanation, the mechanical detection error and the electrical detection error depending on the ambient temperature are collectively explained as an error caused by the temperature change of the resolver 2A. This signal converter may be configured separately outside the resolver 2A, or may be included as a part of the motor speed control device 10, which will be described later. In the following description, a case in which it is incorporated in the resolver 2A will be described.

For example, the motor speed controller 10 is a controller for the inverter 30 that drives the motor 2 . The motor speed control device 10 is an example of a rotational position correction device.

The motor speed control device 10 includes a rotational position correction unit 3, a speed control unit 5, a current control unit 6, a PWM control unit 7 (described as PWM in the figure), a current value conversion unit 8, and a temperature estimation unit. and part 9. Note that the speed control unit 5, the current control unit 6, and the PWM control unit 7 are examples of control units. A general technique may be applied to this control.

The speed control unit 5 multiplies the speed deviation between the speed command value ω ^* and the speed estimated value ωFBK of the motor 2 by a predetermined speed response gain to generate a driving torque command value. The speed command value ω ^* is supplied from a host controller such as a programmable controller (PLC). The speed command value ω ^* is set to a desired value and maintained at that value after setting until the next value is set. The estimated speed value ωFBK of the motor 2 will be described later.

The current controller 6 is connected to the output of the speed controller 5 . The current control unit 6 generates a voltage command based on the difference between the driving torque command value supplied from the speed control unit 5 and the estimated value of the torque current component supplied to the motor 2 (referred to as current iFBK). Output the value V ^* .

The PWM control unit 7 drives the motor 2 by controlling the inverter 30 by PWM control (Pulse Width Modulation control). For example, the input of the PWM control section 7 is connected to the output of the current control section 6 and the output is connected to the inverter 30 . PWM control unit 7 outputs a gate control signal for inverter 30 so as to drive motor 2 according to voltage command value V ^* generated by current control unit 6 .

For example, the wiring connected to the output of the inverter 30 may be provided with a current transformer CT for detecting the phase current of each phase. The current transformer CT may be provided in at least two-phase wiring among the wiring for each phase of the three-phase alternating current.

Based on the instantaneous value of the phase current detected by the current transformer CT and the reference phase .theta. Generate iFBK. The current control unit 6 may perform current control using the current detection value iFBK.

A temperature estimator 9 estimates the temperature T of the motor 2 and the resolver 2A of the motor drive system 1 . For example, the temperature estimator 9 estimates the temperature T based on the magnitude of the phase current (current detection value iFBK) and the voltage command value V ^* . Details of this will be described later.

A first input of the rotational position corrector 3 is connected to the output of the resolver 2A. For example, the rotational position correction unit 3 receives the angle detection value θe2 output from the resolver 2A and uses it for speed control of the motor 2 . A second input of the rotational position corrector 3 is connected to the output of the temperature estimator 9 . For example, the rotational position corrector 3 uses the temperature estimation value output by the temperature estimator 9 for rotational position correction.

For example, the rotational position corrector 3 includes a detected value corrector 31 and a speed converter 32 .
The detection value correction unit 31 includes a correction value generation unit 31a and a subtractor 31b. The correction value generator 31a generates an angle correction value Δθt based on the temperature estimation value output by the temperature estimator 9 . The subtractor 31b subtracts the angle correction value .DELTA..theta.t from the detected angle value .theta.e2 to generate the estimated angle value .theta.e1. The angle correction value Δθt is an example of angle correction information.

The speed conversion unit 32 acquires the estimated angle value θe1 generated by the detected value correction unit 31, and generates the above-described estimated speed value ωFBK and the like based on the estimated angle value θe1.

The motor speed control device 10 includes, for example, a processor such as a CPU. A part or all of the functional units such as the current value converting unit 8 and the temperature estimating unit 9 may be realized, or the above may be realized by a combination of electric circuits (circuitry). The motor speed control device 10 may use a storage area of a storage unit provided therein to perform transfer processing of each data and arithmetic processing for analysis by execution of a predetermined program by a processor.

Next, correction of the angle detection value will be described with reference to FIGS. 2 to 6. FIG.
FIG. 2 is a diagram for explaining the relationship between the magnitude of the output of the motor drive system 1 of the embodiment and the saturation temperature. FIG. 3 is a diagram for explaining the relationship between temperature and time during which the motor drive system 1 of the embodiment is operated. FIG. 4 is a diagram for explaining temperature changes accompanying changes in the operating state of the motor drive system 1 of the embodiment. The output of the motor drive system 1 is, for example, power supplied to the motor 2 (output power). An index corresponding to the amount of electric power supplied to the motor 2 can be applied to the magnitude of the output of the motor drive system 1 .

An example of correcting a deviation of angle information occurring in the detection result of the resolver 2A based on the temperature of the resolver 2A will be described below. The cases illustrated below are applicable when no temperature sensor is installed, or when the environment is such that the temperature cannot be measured directly. In this case, it is preferable to predict the temperature and correct the deviation of the angle information.

The motor 2 in operation generates heat due to the loss. When the operating condition of the motor 2 (the magnitude of the output of the motor drive system 1) changes, the temperature of the motor 2 changes accordingly. The amount of heat generated by the motor 2 depends on the magnitude of the output of the motor drive system 1 . The greater the output of the motor drive system 1, the greater the amount of heat generated. As the output of the motor drive system 1 changes, the surrounding temperature changes due to the heat generated by the motor 2 and the like.
For example, if the output of the motor drive system 1 is maintained at a predetermined level, it saturates at a temperature determined by the output level. The graph in FIG. 2 shows the relationship between the magnitude of the output of the motor drive system 1 (horizontal axis) and the temperature TP at saturation (vertical axis). The relationship between the output P and the temperature TP shown in this graph may be modeled by approximating it with a linear expression as shown in the following equation (1), for example.

TP=k・P+Ta (1)

In equation (1) above, k is the temperature coefficient and Ta is the ambient temperature. This relationship may be defined in advance as a reference table. The temperature at the time when the temperature is saturated can be obtained from the above formula (1), but if the change is slow, the transient state cannot be specified. Therefore, the temperature in the transient state is specified by the following method.

FIG. 3 shows the relationship between the time t (horizontal axis) during which the motor drive system 1 is operated and the ambient temperature (vertical axis). It shows the change in temperature when the magnitude of the output of the motor drive system 1 changes stepwise at the timing of the origin of the horizontal axis shown in FIG.
As described above, when the magnitude of the output of the motor drive system 1 changes, the temperature of the motor 2 and its surroundings changes accordingly. However, in this case, each part has its own thermal resistance and thermal capacity, and the change in temperature T tends to lag behind the change in output. For example, the trend of change in the temperature T in this case may be modeled by approximating it with a first-order lag system as shown in FIG. 3 and the following equation (2).

T＝(TP－T0)・（1－exp(-t/τ))＋T0 ・・・（２）

In the above equation (2), τ is the time constant and T0 is the temperature immediately before the temperature T changes. This relationship may be defined in advance as a reference table.

In the example shown in FIG. 4, the operating state of the motor drive system 1 is switched three times during the period shown in this figure.
In the initial state of the period shown in this figure, the motor drive system 1 stops supplying electric power to the motor 2, so that the motor 2 does not generate heat. The initial temperature T is equal to the ambient temperature Ta.

At time t1, the first operation state switching is performed. The motor drive system 1 starts supplying electric power P1 to the motor 2 and maintains it. When the electric power P1 is continuously supplied to the motor 2, the ambient temperature is expected to rise gradually until it reaches the temperature T1. The relationship between the power amount P1 and the temperature T1 may be derived from the correspondence shown in FIG. 2 described above. Note that the next operating state may be switched before the ambient temperature reaches the temperature T1. In such a case, the trend of change in temperature T changes from that point (for example, time t2).

At time t2, the second operating state switching is performed. The motor drive system 1 starts supplying the electric power P2 to the motor 2, switches the amount of electric power to be supplied, and then maintains this. When the electric power P2 is continuously supplied to the motor 2, the ambient temperature is expected to rise gradually until it reaches the temperature T2. The relationship between the power amount P2 and the temperature T2 may be similarly derived from the corresponding relationship shown in FIG. Note that the next operating state may be switched before the ambient temperature reaches the temperature T2. In such a case, the tendency of change in temperature T changes from that point (for example, time t3).

At time t3, the third switching of the operating state is performed. The motor drive system 1 starts supplying the electric power P3 to the motor 2, switches the amount of electric power to be supplied, and then maintains this. If the electric power P3 is continuously supplied to the motor 2, it is expected that the ambient temperature will drop gradually until it reaches the temperature T3. Similarly, the relationship between the power amount P3 and the temperature T3 may be derived from the corresponding relationship shown in FIG.

By modeling the relationship between the amount of electric power and the temperature in this way, it is possible to correct the detected angle value including an error that depends on the temperature T that changes with a time delay. A more specific example will be described with reference to FIGS. 5 and 6. FIG.

FIG. 5 is a diagram for explaining an angle detection value including an error that depends on the temperature T of the embodiment. FIG. 5 shows the relationship between the physical angle θrm (horizontal axis) and the detected value θe (vertical axis). For example, in a usable situation where the detected value θe contains no error, the detected value θe matches the physical angle θrm. A solid line indicates the detected value θe in such a state. On the other hand, if the detected value θe contains an error dependent on the temperature T, the error ΔθT contained in the detected value θe manifests itself as an offset component with respect to the physical angle θrm. A dashed line indicates the detected value θe in such a state. This error .DELTA..theta.T exhibits a tendency clearly different from that of the component whose value varies randomly from measurement to measurement.

For example, in a configuration that can detect an angle range of 0° to 360°, when the physical angle θrm of the shaft of the motor 2 to be detected by the resolver 2A is θm, if the error ΔθT is not included, then The detected value θe becomes the detected value θe1 equal to θm of the physical angle θrm. On the other hand, if the error ΔθT is included, the detected value θe at that time becomes a detected value θe2 different from θm of the physical angle θrm. As shown in the following formula (3), the difference between the detected value θe1 and the detected value θe2 is the error ΔθT. Since such a tendency occurs regardless of the angle of the shaft, almost the same amount of error ΔθT is included at any angle.

ΔθT=θe2−θe1 (3)

The detected value θe2 in the situation shown in FIG. 5 includes the error ΔθT of the offset component that depends on the temperature T. The relationship between the temperature T and the offset component error ΔθT dependent thereon will be described with reference to FIG. FIG. 6 is a diagram for explaining the relationship between the temperature and the error in the detected angle value according to the embodiment. FIG. 6 shows the relationship between the temperature T (horizontal axis) and the error θT (vertical axis) of the detected angle value.

Since there is a tendency shown in this graph between the temperature T and the error θT in the detected angle value, the relationship between the temperature T and the error ΔθT in the detected angle value can be expressed by the following equation (4). It is preferable to model by approximating with a linear expression as shown in .

ΔθT=a・(T_est−T_ref)+b (4)

In the above equation (4), T_est is the predicted temperature, T_ref is the reference temperature (eg, 25° C.), and a and b are predetermined constants. Note that a corresponds to the slope of the graph in FIG. b corresponds to the intercept of the graph in FIG. It has been clarified that the estimated value of the error ΔθT of the angle detection value can be analytically derived by the above procedure.

Therefore, as shown in the following equation (5), by using the estimated value of the error ΔθT of the angle detection value as the compensation amount θc of the angle detection value θe2, the angle detection value θe1 is obtained by correcting the angle detection value θe2. be able to.

θe1=θe2−θc=θe2−ΔθT (5)

Using the principle described above, the correction process may be implemented, for example, according to the procedure described below.
The temperature estimator 9 derives the temperature T based on the magnitude of the phase current (current detection value iFBK) and the voltage command value V ^* using the above equations (1) and (2).
A detection value correction unit 31 of the rotational position correction unit 3 derives an estimated value of the error ΔθT of the angle detection value using equation (4). The detected value correction unit 31 uses this as a compensation amount θc for the detected angle value θe2 to derive the detected angle value θe1 by correcting the detected angle value θe2.
The speed converter 32 generates the speed estimated value ωFBK based on the angle estimated value θe1 generated by the detected value corrector 31 .
The speed control unit 5, the current control unit 6, and the PWM control unit 7 control the motor 2 so that the estimated speed value ωFBK becomes the speed command value ω ^* . The speed controller 5 , current controller 6 , and PWM controller 7 are examples of a controller that controls the motor 2 .
The above procedure enables correction of the detection result of the resolver 2A.

According to the above embodiment, the motor speed control device 10 (rotational position correction device) includes the detected value correction section 31 . Based on the estimated value or the detected value of the temperature of the resolver 2A that changes according to the output of the motor 2, the detected value correction unit 31 corrects the detected angle value of the resolver 2A corresponding to the temperature. Thereby, the motor speed control device 10 can reduce the temperature dependence of the detection result of the shaft angle by the resolver 2A.

(First Modification of First Embodiment)
Although one method of estimating the temperature T of the resolver 2A has been illustrated in the above embodiment, it is not limited to this method. In this modified example, a case will be described in which the position that defines the temperature T is set to a specific position. For example, a specific position is defined on the flange portion of the shaft of the resolver 2A.
In this case, the detection value correcting section 31 preferably holds in advance data on the relationship between the temperature Tf of the flange portion on the resolver 2A side and the error ΔθT of the angle detection value. As a result, the phase error (error .DELTA..theta.T) caused by heat conduction from the bearing of the motor 2 through its shaft and flange portion can be dealt with in a similar manner.

(Second modification of the first embodiment)
In addition, in this modification, instead of estimating the temperature T of the resolver 2A, the temperature of the motor 2 main body, the resolver 2A main body, the flange that connects the shaft of the motor 2 and the shaft of the resolver 2A, etc. is detected during operation, The result may be used as the temperature T of the resolver 2A.

(Second embodiment)
A second embodiment will be described with reference to FIG. The configuration of the first embodiment used one resolver 2A. In the present embodiment, instead of this, a case will be described in which a plurality of resolvers 2A are used to make the rotation detection portion redundant. The number of resolvers 2A is not limited to the following examples and may be determined arbitrarily.

FIG. 7 is a schematic configuration diagram of the motor drive system of the second embodiment.
The motor drive system 1A includes, for example, a resolver 2B in addition to the resolver 2A of the motor drive system 1. FIG. The resolver 2B has the same configuration as the resolver 2A. Reference numerals are changed for the sake of explanation. The motor drive system 1A includes a motor speed control device 10A instead of the motor speed control device 10. FIG.

The motor speed control device 10A may correct the angle detection values of the resolvers 2A and 2B using a common correction amount for the detection results of the resolvers 2A and 2B. Alternatively, the motor speed control device 10A may correct the angle detection values of the resolvers 2A and 2B using different correction amounts for the detection results of the resolvers 2A and 2B.

The latter will be described in more detail below.
Motor speed controller 10A is connected to motor 2 and resolvers 2A and 2B. The motor speed control device 10A controls the speed of the motor 2 so that the actual speed of the motor 2 detected by either one of the resolvers 2A and 2B matches the desired speed command value ω ^* . At that time, the motor speed control device 10A switches the detection results of the resolver 2A and the resolver 2B.

The motor speed controller 10A replaces the rotational position corrector 3, the speed controller 5, and the temperature estimator 9 of the motor speed controller 10 with rotational position correctors 3A and 3B, a speed controller 5A, It comprises temperature estimators 9A and 9B.

The rotational position correction units 3A and 3B are configured in the same manner as the rotational position correction unit 3, for example.
A detection value correction unit 31A of the rotational position correction unit 3A is connected to the output of the resolver 2A, generates an angle correction value Δθt based on the temperature TA estimated by the temperature estimation unit 9A, and uses this to correct the angle Generate an estimate θe1A. A velocity conversion unit 32A of the rotational position correction unit 3A generates an estimated velocity value ωFBKA based on the estimated angle value θe1A.

Similarly, the detected value corrector 31B (not shown) of the rotational position corrector 3B is connected to the output of the resolver 2B and generates an angle correction value Δθt based on the temperature TB estimated by the temperature estimator 9B. This is used to generate the corrected angle estimate θe1B. A velocity conversion section 32B (not shown) of the rotational position correction section 3B generates an estimated velocity value ωFBKB based on the estimated angle value θe1B. The detection value correction units 31A and 31A correspond to the detection value correction unit 31 described above. The speed converters 32A and 32B correspond to the speed converter 32 described above.

The speed control unit 5A adjusts the speed deviation ΔωA between the speed command value ω ^* and the estimated speed value ωFBKA of the motor 2, or the speed deviation ΔωB between the speed command value ω ^* and the estimated speed value ωFBKB of the motor 2 to a predetermined value. A drive torque command value is generated by multiplying each speed response gain. For example, the speed control unit 5A is configured to select and use either the speed deviation ΔωA or the speed deviation ΔωB for system switching of the redundant configuration.

According to this embodiment, the motor drive system 1A can be configured redundantly by redundantly configuring the resolvers 2A, 2B, and the rotational position correction units 3A and 3B as described above.

(Modification of Second Embodiment)
An example of redundant configuration has been described in the second embodiment. In this modified example, an example in which there is an individual difference in the characteristics of the resolvers 2A and 2B will be described.
The detection results of the resolvers 2A and 2B may contain errors due to individual differences in characteristics. The detection value correcting section 31A and the detection value correcting section 31B can absorb individual differences in the characteristics of the resolvers 2A and 2B by performing correction so as to absorb individual differences in the characteristics of the resolvers.

If the degree of influence of the heat of the motor 2 differs between the resolver 2A and the resolver 2B, this can be absorbed. For example, when the resolvers 2A and 2B are arranged on the shaft of the motor 2 at different positions in the direction away from the motor 2, the heat generated by the motor 2 and transferred to the resolver 2A is transferred to the resolver 2B. more than the heat transferred to it. In such a case, a temperature difference occurs between the resolver 2A temperature and the resolver 2B temperature. The detected value correcting section 31A and the detected value correcting section 31B may each calculate the angle correction value Δθt including this temperature difference as a condition.

(Third Embodiment)
A third embodiment will be described with reference to FIG. In the motor drive system 1 of the first embodiment, a basic example in which the correction amount calculation standard is unchanged has been described. In the present embodiment, a motor drive system 1B that can switch the calculation standard of the correction amount according to the operating conditions will be described.

FIG. 8 is a schematic configuration diagram of the motor drive system of the third embodiment.
The motor drive system 1B includes a motor speed control device 10B that replaces the motor speed control device 10 of the motor drive system 1. FIG.

The motor speed control device 10B further includes a history information processing unit 4 and a rotational position correcting unit 3C instead of the rotational position correcting unit 3 in addition to the motor speed control device 10 .

The history information processing unit 4 includes, for example, a history information recording processing unit 41, a history information analysis processing unit 42, a control characteristic switching processing unit 43, and a storage unit 44.

The history information recording processing unit 41 records the control information indicating the control state in the storage unit 44 at any time to generate history information.

The history information analysis processing unit 42 analyzes the history information recorded in the storage unit 44 to detect, for example, changes over time and sudden changes. These change methods may apply statistical analysis methods applicable to anomaly detection. For example, when it is detected that the detection characteristic of the resolver 2A has changed from the past one, the control characteristic switching processing unit 43 sets the angle correction value Δθt for the detection result of the resolver 2A to a value suitable for the current characteristic. The rotational position corrector 3C is controlled so as to change to .

The rotational position correction section 3C includes a detection value correction section 31C that replaces the detection value correction section 31. FIG. The detected value corrector 31C corresponds to the detected value corrector 31 . The detection value correction unit 31</b>C further switches the angle correction value Δθt under the control of the history information analysis processing unit 42 . This switching makes the angle correction value Δθt suitable for the current characteristics.

The method of changing to the one suitable for the current characteristics may be a method of selecting from among predetermined candidates, generating an angle correction value Δθt based on the current detection result, may be a method of switching to the angle correction value Δθt generated in .

According to this embodiment, it is possible to find a change in the detection characteristic of the resolver 2A by comparing the operating state and the actually corrected angle correction amount data with the past data in the history information. . The curve data can be updated in accordance with changes in the detection characteristics of the resolver 2A to cope with aging.

According to at least one embodiment described above, the rotational position correction device includes the detection value correction section. A resolver detects the angle of the shaft of the motor. The detection value correction unit corrects the angle detection value of the resolver corresponding to the temperature based on the estimated value or the detection value of the temperature of the resolver that changes according to the output of the motor. Thereby, the rotational position correcting device can reduce the temperature dependency of the detection result of the shaft angle by the resolver.

While several embodiments of the invention have been described, these embodiments have been presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, as well as the scope of the invention described in the claims and equivalents thereof.

1, 1A, 1B motor drive system 2 motor 3, 3A, 3B, 3C rotational position correction unit 4 history information processing unit 5, 5A speed control unit 6 current control unit 7 PWM control unit 8 current value Conversion unit 9, 9A Temperature estimation unit 10 Motor speed control device (rotational position correction device) 20 DC power supply 30 Inverter 31, 31A, 31B, 31C Detection value correction unit 32, 32A, 32B Speed conversion unit

Claims (9)

A rotational position correction device for a motor in which an angle of a shaft is detected by a resolver,
A rotational position correction device comprising: a detection value correction unit that corrects an angle detection value of the resolver corresponding to the temperature based on an estimated value or a detection value of the temperature of the resolver that changes according to the output of the motor. a temperature estimator that estimates the temperature of the resolver and generates a temperature estimate;
The detection value correction unit is
2. The rotational position correction device according to claim 1, wherein the temperature estimated value is used to correct the angle detection value of the resolver. The temperature estimator,
approximating a change in temperature of the resolver with a first-order lag system to generate the temperature estimate;
3. The rotational position correction device according to claim 2. The temperature estimator,
estimating the temperature of the resolver based on the magnitude of power supplied to the motor;
4. The rotational position correction device according to claim 2 or 3. A motor drive system for a motor whose shaft angle is detected by a resolver,
a detection value correction unit that corrects the angle detection value of the resolver corresponding to the temperature based on the estimated value or the detection value of the temperature of the resolver that changes according to the output of the motor;
A motor drive system comprising: a control unit that controls the motor using the corrected angle detection value. a temperature estimator that estimates the temperature of the resolver and generates a temperature estimate;
The detection value correction unit is
correcting the detected angle value of the resolver using the estimated temperature value and angle correction information based on the power supplied to the motor;
6. A motor drive system according to claim 5. a motor whose shaft angle is detected by the resolver;
7. The motor drive system according to claim 5 or 6, comprising the resolver. Control information indicating the control state of the motor is recorded at any time to generate history information, and by analyzing the history information, when it is detected that the detection characteristic of the resolver has changed, the angle of the resolver is detected. 8. The motor drive system according to any one of claims 5 to 7, further comprising a control characteristic switching processor that changes the angle correction value for the detected value to one suitable for the current characteristic. A method for correcting a rotational position of a motor in which an angle of a shaft is detected by a resolver,
A method of correcting a rotational position, comprising the step of correcting an angle detection value of the resolver corresponding to the temperature, based on an estimated value or a detection value of the temperature of the resolver that changes according to the output of the motor.

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