JP2010136583A - Torque controller for electric motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a torque controller for an electric motor, capable of properly controlling the operation state of an electric motor while performing torque control of the electric motor. <P>SOLUTION: The torque controller 10 for the electric motor includes: a set torque generator 21 for generating a set torque Tmc as a target value of a load torque Tl acting to a load, out of motor torque Tm outputted from a motor 11; a disturbance torque observer 34 and a current-torque monitor 37 for estimating a torque estimation value Ttl corresponding to a current Itl for the load torque; and a current controller 26 and a speed controller 33 for controlling so that the torque estimation value Ttl may be converged to the set torque Tmc. The speed controller 33 controls the rotation speed so that the actual rotation speed ωm of the motor 11 may be changed in accordance with a predetermined change in rotation speed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a torque control device for an electric motor.

Conventionally, for example, a clutch provided between a motor for driving a vehicle and a wheel for connecting / disconnecting power, an accumulator for accumulating hydraulic pressure for clutch engagement, and an electric oil pump for supplying hydraulic pressure to the accumulator, 2. Description of the Related Art A vehicle control device is known that controls the operation of an electric oil pump so that the pressure of an accumulator becomes equal to or higher than a predetermined value by detection means (see, for example, Patent Document 1).
JP 2003-54279 A

By the way, in the vehicle control apparatus according to the above-described prior art, the motor is simply driven and controlled so as to output a desired torque, and the motor drive apparatus corresponds to the operation state of the motor and the pressure of the accumulator. Since the relationship is not grasped, there is a possibility that the rotational speed of the motor may be excessively increased by increasing the pressure of the accumulator even when an abnormality such as leakage in the hydraulic circuit occurs. Therefore, there arises a problem that it is impossible to grasp whether or not the control apparatus as a whole is in an appropriate operating state.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electric motor torque control device capable of appropriately controlling the operating state of the electric motor while performing torque control of the electric motor.

  In order to solve the above-described problems and achieve the object, the torque control device for an electric motor according to the first aspect of the present invention includes an energization control means for controlling energization to the electric motor (for example, the motor drive device in the embodiment). 27), a torque command value generating means (for example, a set torque generator 21 in the embodiment) for generating a torque command value for a load torque acting on a load among torques output from the electric motor, and the load torque Load torque estimating means (for example, disturbance torque observer 34 and current-torque monitor 37 in the embodiment), and the load torque estimated by the load torque estimating means is generated by the torque command value generating means. Control means (for example, the current controller 26 and the speed controller 33 in the embodiment) for performing control so as to converge to the torque command value. With the door, said control means performs speed control rotation speed of the motor so as to vary in accordance with the predetermined rotational speed change characteristics.

  The torque control apparatus for an electric motor according to the second aspect of the present invention determines whether or not the load torque estimated by the load torque estimating means has converged to the torque command value generated by the torque command value generating means. And when the load torque is determined to have converged to the torque command value in the determination result of the determination means (for example, the torque arrival determination device 38 in the embodiment) and the determination result of the determination means. An abnormality determination unit (for example, an abnormality determination unit 39 in the embodiment) that determines whether or not there is an abnormality depending on whether or not it is within a predetermined range.

According to the torque control apparatus for an electric motor according to the first aspect of the present invention, since the rotational speed change characteristic of the rotational speed is controlled while controlling the torque of the electric motor, the control stability of the entire control apparatus can be improved. it can.
According to the torque control device for an electric motor according to the second aspect of the present invention, it is possible to appropriately determine the presence or absence of abnormality as the entire control device, and to prevent occurrence of problems such as excessive increase in the rotational speed of the electric motor. can do.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a torque control device for an electric motor according to the present invention will be described with reference to the accompanying drawings.
The motor torque control device 10 (hereinafter simply referred to as the torque control device 10) according to this embodiment controls the torque of the motor 11, and, for example, as shown in FIG. , Command current output unit 23, low-pass filter 24, current deviation calculation unit 25, current controller 26, motor drive device 27, command speed generator 31, speed deviation calculation unit 32, speed A controller 33, a disturbance torque observer 34, a load torque current output unit 35, a command current generator 36, a current-torque monitor 37, a torque arrival determiner 38, and an abnormality determiner 39 are configured. Has been.

  The set torque generator 21 outputs a load torque Tl that is applied to a load driven by the motor 11 other than the acceleration torque that contributes to the acceleration of the motor 11 out of the torque output from the motor 11. Is output as a set torque Tmc. For example, when the motor 11 is provided in an electric oil pump, the torque that contributes to the generation of hydraulic pressure by the electric oil pump is the load torque.

The torque-current converter 22 converts the set torque Tmc output from the set torque generator 21 into a current value Itmc corresponding to the set torque Tmc.
For example, as shown in FIG. 2, the command current output unit 23 generates a command current by using the current value Itmc output from the torque-current converter 22 and the value of the opposite sign as the upper limit value and the lower limit value for the command current Imcc. Limit processing is performed on the command current Imc output from the device 36 to generate the command current Imcc. In addition, the value of the different sign of the current value Itmc may be set to an arbitrary value considering the system.

The low-pass filter 24 removes high-frequency components of the command current Imcc, for example, by removing resonance in the driving force transmission system to which the motor 11 is connected.
The current deviation calculation unit 25 is a current between the command current Imcc output from the low-pass filter 24 and the actual current Im output from the actual current output unit 41 that detects and estimates the actual current supplied to the motor 11. Deviation ΔIm (= Imcc−Im) is calculated.

The current controller 26 controls and amplifies the current deviation ΔIm output from the current deviation calculator 25 by, for example, a PI (proportional / integral) operation, and calculates the voltage command Vc.
The motor drive device 27 includes, for example, an inverter for energizing the motor 11 with a current corresponding to the command current Imcc, and drives the inverter based on the voltage command Vc output from the current controller 26 to To control.

The command speed generator 31 uses, as a command value for the actual rotation speed ωm of the motor 11, a command rotation speed ωmc corresponding to a predetermined rotation speed change characteristic (for example, a rotation speed change characteristic due to a constant acceleration, a primary delay response characteristic, etc.) Is output.
The speed deviation calculation unit 32 determines the command rotation speed ωmc output from the command speed generator 31 and the rotation angle of the motor 11 output from the angle sensor 42 (rotation angle of the magnetic poles of the rotor from a predetermined reference rotation position). A speed deviation Δωm with the actual rotational speed ωm is calculated.
The speed controller 33 controls and amplifies the speed deviation Δωm output from the speed deviation calculator 32 by, for example, a PI (proportional / integral) operation, and calculates the command current Ima.

  As shown in FIG. 3, the disturbance torque observer 34 is, for example, a zero-order disturbance observer, and depends on the actual current Im output from the actual current output unit 41 and the actual rotational speed ωm output from the angle sensor 42. Based on the torque constant Kt of the motor 11, the moment of inertia J of the motor 11, the Laplace operator s, and the disturbance observer gain gd, the load torque current Itl corresponding to the load torque Tl is calculated.

The load torque current output unit 35 selects either the load torque component current Itl output from the disturbance torque observer 34 or a predetermined value (for example, zero) and newly outputs the load torque component current Itl.
The command current generator 36 calculates the command current Imc by adding the command current Ima output from the speed controller 33 and the load torque current Itl output from the load torque current output unit 35.

The current-torque monitor 37 converts the load torque current Itl output from the disturbance torque observer 34 into an estimated torque value Ttl corresponding to the load torque current Itl.
Based on the estimated torque value Ttl output from the current-torque monitor 37 and the set torque Tmc output from the set torque generator 21, the torque attainment determination unit 38 determines whether the estimated torque value Ttl converges to the set torque Tmc. Determine whether or not.

The abnormality determiner 39 determines that the actual rotational speed ωm output from the angle sensor 42 is within a predetermined normal range when it is determined in the determination result of the torque arrival determiner 38 that the estimated torque value Ttl has converged to the set torque Tmc. If this determination result is “YES”, it is determined that the load (eg, hydraulic circuit) is normal. On the other hand, if this determination result is “NO”, the load It is determined that (for example, the hydraulic circuit) is abnormal.
Further, the abnormality determiner 39 determines whether or not the estimated torque value Ttl at the time when the actual rotational speed ωm of the motor 11 reaches a predetermined speed is within a predetermined normal torque range. If “YES”, it is determined that the load (eg, hydraulic circuit) is normal. On the other hand, if this determination result is “NO”, it is determined that the load (eg, hydraulic circuit) is abnormal. .

  The torque control apparatus 10 for an electric motor according to the present embodiment has the above-described configuration. Next, the operation of the torque control apparatus 10 will be described.

For example, as shown in FIG. 4, when the operation of the motor 11 is normal, the estimated torque value corresponds to the output of the motor torque Tm corresponding to the load torque Tl of the appropriate initial torque value Tlinit. When an appropriate set torque Tmc is output at time t1 when Ttl is the initial torque value Tlinit, the load torque Tl and the motor torque Tm tend to increase so as to converge to the set torque Tmc after this time t1. As a result, the estimated torque value Ttl also changes so as to converge to the set torque Tmc.
At this time, if, for example, an increase in rotational speed at a predetermined constant acceleration is set as the predetermined rotational speed change characteristic, the command rotational speed ωmc increases at a predetermined constant acceleration, and accordingly, the actual rotational speed ωm Changes to an increasing tendency at a predetermined constant acceleration so as to follow the command rotational speed ωmc. When the actual rotational speed ωm increases at a predetermined constant acceleration in this way, the motor torque Tm changes in an increasing tendency while maintaining a value larger than the load torque Tl by a constant acceleration torque.

For example, when the motor 11 is provided in an electric oil pump, the torque that contributes to the generation of hydraulic pressure by the electric oil pump becomes the load torque Tl, and the flow rate of the hydraulic oil in the hydraulic circuit including the electric oil pump is the actual speed of the motor 11. The value corresponds to the rotational speed ωm. If the relationship between the hydraulic oil flow velocity and the hydraulic pressure is known in the normal hydraulic circuit, the normal flow velocity range that the hydraulic oil flow velocity can take when the actual hydraulic pressure reaches the predetermined target hydraulic pressure is known. Become.
Then, as the load torque Tl approaches the set torque Tmc, the oil pressure approaches the target oil pressure, and the flow speed of the hydraulic oil approaches the normal flow speed range, so that the increase in the actual rotational speed ωm, that is, the increase at a predetermined constant acceleration becomes dull. As the acceleration torque decreases, the motor torque Tm and the load torque Tl converge.
At time t2 when the load torque Tl and the motor torque Tm coincide with the set torque Tmc, the estimated torque value Ttl also coincides with the set torque Tmc. At this time, the actual rotational speed ωm of the motor 11 is a value within a predetermined normal range corresponding to a normal flow velocity range that can be taken by the hydraulic oil flow velocity in the hydraulic circuit. The predetermined normal range for the actual rotational speed ωm of the motor 11 is set to a range smaller than the upper limit value of the command rotational speed ωmc, and the upper limit value ωu of the command rotational speed ωmc is, for example, the motor 11 or a load (for example, The value is such that no abnormality occurs in the operation of the electric oil pump or the like.

On the other hand, when the load torque Tl is abnormal due to an abnormality in the hydraulic circuit, for example, as shown in FIG. 5, the time when the load torque Tl, the motor torque Tm, and the estimated torque value Ttl coincide with the set torque Tmc. At t2, the actual rotational speed ωm of the motor 11 becomes smaller than the predetermined normal range, or as shown in FIG. 6, at time t2 when the load torque Tl, the motor torque Tm, and the estimated torque value Ttl coincide with the set torque Tmc. The actual rotational speed ωm of the motor 11 becomes larger than the predetermined normal range.
Thereby, when it is determined in the determination result of the torque attainment determination unit 38 that the estimated torque value Ttl has converged to the set torque Tmc, the actual rotation speed ωm output from the rotation speed calculator 30 must be within a predetermined normal range. In this case, it is determined that the hydraulic circuit is abnormal.

  Further, when the load torque Tl is excessively low due to, for example, an abnormality in the hydraulic circuit, for example, as shown in FIG. 7, until the actual rotational speed ωm of the motor 11 reaches the upper limit value of the command rotational speed ωmc. Increase. Therefore, if the estimated torque value Ttl at the time when the actual rotational speed ωm of the motor 11 reaches the predetermined speed is not within the predetermined normal torque range, it is determined that the hydraulic circuit is abnormal.

As described above, according to the torque control apparatus 10 for an electric motor according to the present embodiment, the estimated torque value Ttl of the load torque Tl of the motor 11 is calculated, and whether or not the estimated torque value Ttl converges to the set torque Tmc. Since the motor torque Tm of the motor 11 is controlled while monitoring and the rotational speed change characteristic of the actual rotational speed ωm is controlled, the control stability of the entire control device can be improved.
Furthermore, since the load torque current Itl corresponding to the estimated torque value Ttl of the load torque Tl of the motor 11 is fed back to the command current Ima, it is possible to prevent the load torque Tl from fluctuating rapidly.
In addition, whether or not there is an abnormality in the load (for example, the hydraulic circuit) is appropriately determined by determining whether or not the actual rotational speed ωm when the estimated torque value Ttl converges to the set torque Tmc is within a predetermined normal range. be able to.
Furthermore, even if the load torque Tl is too small, the actual rotational speed ωm of the motor 11 is controlled until it reaches the upper limit value of the command rotational speed ωmc, so is the load (for example, a hydraulic circuit) abnormal? In addition, it is possible to determine whether or not the motor 11 has an excessive increase in the actual rotational speed ωm.

  In the above-described embodiment, the motor 11 is provided in the electric oil pump, and the load torque Tl contributes to the generation of hydraulic pressure by the electric oil pump. However, the present invention is not limited to this, but other than the electric oil pump. Torque control may be performed on the load torque Tl acting on the load.

In the embodiment described above, for example, the angle sensor 42 may be omitted, and a magnetic pole position estimation device that estimates the magnetic pole position of the motor 11 may be provided.
In the above-described embodiment, the actual current output unit 41 may include a phase current sensor that directly detects each phase current supplied to the motor 11 including, for example, a three-phase AC brushless DC motor. . Alternatively, instead of the phase current sensor, a DC-side current sensor that detects a DC-side current of the inverter bridge circuit between the inverter bridge circuit of the motor drive device 27 and the negative terminal or the positive terminal of a power source such as a battery. May be provided. In this case, each phase current may be estimated based on the detection signal output from the DC side current sensor and the gate signal input to the inverter of the motor drive device 27.
In the above-described embodiment, the motor 11 may be, for example, a three-phase AC brushless DC motor or another type of motor.

It is a block diagram of the torque control apparatus of the electric motor which concerns on embodiment of this invention. It is a graph which shows the corresponding | compatible relationship between the command current Imc and the command current Imcc which concerns on embodiment of this invention. It is a block diagram of the disturbance torque observer which concerns on embodiment of this invention. It is a graph which shows an example of the time change of rotational speed, torque, and torque estimated value Ttl when operation | movement of the motor which concerns on embodiment of this invention is normal. It is a graph which shows an example of the time change of rotational speed, torque, and torque estimated value Ttl when operation | movement of the motor which concerns on embodiment of this invention is abnormal. It is a graph which shows an example of the time change of rotational speed, torque, and torque estimated value Ttl when operation | movement of the motor which concerns on embodiment of this invention is abnormal. It is a graph which shows an example of the time change of rotational speed, torque, and torque estimated value Ttl when operation | movement of the motor which concerns on embodiment of this invention is abnormal.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Motor torque control apparatus 11 Motor 21 Set torque generator (torque command value generation means)
26 Current controller (control means)
27 Motor drive device (energization control means)
33 Speed controller (control means)
34 Disturbance torque observer (load torque estimation means)
37 Current-torque monitor (load torque estimating means)
38 Torque arrival determination device (determination means)
39 Abnormality determination device (abnormality determination means)

Claims (2)

Energization control means for controlling energization to the motor;
Torque command value generating means for generating a torque command value for a load torque acting on a load among torques output from the motor;
Load torque estimating means for estimating the load torque;
Control means for performing control so that the load torque estimated by the load torque estimating means converges on the torque command value generated by the torque command value generating means,
The motor torque control apparatus according to claim 1, wherein the control means performs rotation speed control such that the rotation speed of the electric motor changes in accordance with a predetermined rotation speed change characteristic. Determining means for determining whether or not the load torque estimated by the load torque estimating means has converged to the torque command value generated by the torque command value generating means;
An abnormality determination that determines whether or not there is an abnormality depending on whether or not the rotation speed of the electric motor is within a predetermined range when it is determined in the determination result of the determination means that the load torque has converged to the torque command value. The torque control apparatus for an electric motor according to claim 1, further comprising: means.

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