JPH07327381A - Current amplifier controller - Google Patents

Abstract

PURPOSE:To suppress the power consumption by a suitable motor drive current when the motor is operated in a highest rotating area by controlling the switching of a fundamental power transistor based on a motor input current and the transistor switching time. CONSTITUTION:A motor counter-electromotive voltage estimating unit (g) inputs a motor position current and a motor angle position, and estimates the counter- electromotive voltage of a motor (a) by considering a maximum angle to be decided according to the physical characteristics of the motor (a). A fundamental switching time calculator (h) inputs a motor power source voltage and the motor counter-electromotive voltage, and decides a fundamental switching time of a power transistor (b) according to the previously measured impedances of the motor (a) and the transistor (b). A power transistor switching controller (i) controls the switching of the transistor (b) based on the motor input current and the transistor switching time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention corrects the influence of the back electromotive force of a motor when the motor is driven by a current amplifier which does not feed back the current, in consideration of the maximum angular velocity determined by the power supply voltage of the motor. However, the present invention relates to a current amplification control device having a method for eliminating an error between a motor input current and a command current.

[0002]

2. Description of the Related Art Conventionally, as a current amplification control device applied to a motor-driven four-wheel steering vehicle, for example, one shown in FIG. 7 is known.

FIG. 7 shows a controller for controlling the positioning of the motor 1. The motor positioning control calculator 2 calculates a current command value IB based on the motor angle position command value θB and the motor angle position signal θ, and the motor positioning control calculation. The current amplification control device 3 controls the motor input current according to the current command value IB from the section 2. Then, the current amplification control device 3 detects the actual motor current I and feeds it back to obtain the motor current I that matches the current command value IB.

[0004]

However, in the above-mentioned conventional current amplification control device, the triangular wave generator and the right rotation circuit section are included in the current detection section 4 and the current feedback section 5 for detecting the actually flowing motor current I. However, the cost of the controller is high because of the need for a left-handed rotation circuit unit.

Therefore, the present applicant has previously filed Japanese Patent Application No. 6-16.
In No. 133 (filed on February 10, 1994), the back electromotive force of the motor is estimated from the motor angular position and the current command value, and the effective voltage of the motor is calculated from the motor power supply voltage and the estimated back electromotive force. Then, the power transistor switching time is calculated from the motor effective voltage, and the power transistor is directly switched from the calculation device based on the calculation result, whereby the motor control unit can be operated without feeding back the motor current. We proposed a device that can obtain a motor current that matches the current command value from.

However, in the preceding current amplification control device, the motor back electromotive voltage is estimated by estimating the motor angular velocity. Normally, the angular velocity of the motor is limited by the magnitude of the motor power supply voltage.

Therefore, in this prior apparatus, since the estimated value of the angular velocity is not limited, the back electromotive force cannot be accurately estimated in the place where the motor operates at the maximum rotation. Therefore, there remains a problem that the current command value becomes larger than necessary and the power consumption becomes high.

The present invention has been made by paying attention to such a problem. A first object of the present invention is to provide a current detection unit and a current detection unit in a current amplification control device for controlling a motor current based on a current command value. It is an object of the present invention to provide a device that does not require a feedback circuit and is cost-effective, and that can suppress power consumption by an appropriate motor drive current when the motor operates in the maximum rotation range.

In addition to the first object, the second object is to improve the estimation accuracy of the motor back electromotive force and to provide a positioning response of the motor which substantially matches the design target even when the motor rotates at a high speed. To get.

A third object is to easily limit the motor angular velocity estimation in addition to the first and second objects.

[0011]

In order to achieve the first object, the current amplification control device according to the first aspect of the present invention provides a current to the motor a as shown in the claim correspondence diagram of FIG. Power transistor part b to supply and motor a
Motor-angular position detection means c for detecting the angular position of the motor a, motor power supply voltage detection means d for detecting the power supply voltage of the motor a, and motor input current for obtaining the positioning and responsiveness of the motor a desired by the designer. A motor positioning control section e for calculating the motor positioning current, a motor input current determining section f for inputting the motor positioning current, and a motor input current determining section f for determining the motor input current; Motor back electromotive force estimation part g which estimates the back electromotive voltage of the motor a in consideration of the maximum angular velocity determined by the dynamic characteristics, and the motor a and the motor a measured in advance by inputting the motor power supply voltage and the motor back electromotive force. A basic switch for determining the basic switching time of the power transistor section b according to the impedance of the power transistor section b. And a power transistor switching control section i for controlling switching of the power transistor section b based on the motor input current and the basic power transistor switching time. To do.

In order to achieve the second object, the current amplification control device according to the second aspect of the present invention is the current amplification control device according to the first aspect, as shown in the claim correspondence diagram of FIG. A motor dynamic characteristic compensating section j for calculating a motor input current for keeping the dynamic characteristic of the motor constant is provided, and the motor input current determining section f inputs the motor positioning current and the motor dynamic characteristic compensating current,
The motor input current is determined, and the motor back electromotive voltage estimation unit g is used to estimate the back electromotive voltage by using the dynamic characteristic and the motor positioning current that are made constant by the motor dynamic characteristic compensation unit j. It is characterized by

In order to achieve the third object, the current amplification control device according to the third aspect of the present invention is the current amplification control device according to the second aspect, as shown in the claim correspondence diagram of FIG. The limitation of the estimation of the motor angular velocity in the motor back electromotive force estimation unit g is realized by an estimator that limits the input.

[0014]

The operation of the first invention will be described.

When the current is supplied from the power transistor section b to the motor a, the motor positioning control section e calculates the motor input current for obtaining the positioning and responsiveness of the motor a desired by the designer, and determines the motor input current. In part f, the motor positioning current is input and the motor input current is determined.

On the other hand, in the motor back electromotive force estimation unit g, the motor positioning current and the motor angular position from the motor angular position detection means c are input, and the maximum angular velocity determined by the physical characteristics of the motor a is taken into consideration. The back electromotive force of a is estimated. Then, in the basic switching time calculation unit h, the motor back electromotive force estimated as the motor power supply voltage from the motor power supply voltage detection means d is input,
The basic switching time of the power transistor part b is determined by the impedance of the motor a and the power transistor part b measured in advance.

Then, the power transistor switching control section i controls the switching of the power transistor section b based on the motor input current and the basic power transistor switching time.

Therefore, the maximum angular velocity determined by the physical characteristics of the motor a is taken into consideration in estimating the back electromotive force of the motor a, even though the current detection unit and the current feedback circuit are not required unlike the conventional device. Thus, when the motor a operates in the maximum rotation range, a high estimation accuracy of the back electromotive force is secured, and the motor a is driven by an appropriate motor drive current that does not increase more than necessary.

The operation of the second invention will be described.

In determining the input current to the motor a, the motor input current determining section f inputs the motor positioning current from the motor positioning control section e and the motor dynamic characteristic compensating current from the motor dynamic characteristic compensating section j. , The motor input current is determined.

In estimating the motor back electromotive force,
In the motor back electromotive force estimation unit g, the back electromotive force is estimated using the motor positioning current from the motor positioning control unit e and the dynamic characteristics made constant by the motor dynamic characteristic compensation unit j.

Therefore, by compensating the dynamic characteristic of the motor a, the motor input current is determined so that the dynamic characteristic of the motor a is always constant, and the counter electromotive voltage is estimated using the constant dynamic characteristic. As a result, it is possible to improve the accuracy of estimating the back electromotive force and obtain a positioning response of the motor a that substantially matches the design target even when the motor a is rotated at a high speed, which is affected by the dynamic characteristics.

Next, the operation of the third invention will be described.

The limitation on the estimation of the motor angular velocity in the motor back electromotive force estimation section g is realized by limiting the input to the estimator.

[0025]

Embodiments of the present invention will be described below with reference to the drawings.

First, the structure will be described.

FIG. 2 is a block diagram showing a current amplification control device according to the embodiment of the present invention.

As shown in FIG. 2, the apparatus of the embodiment comprises a motor 100 (corresponding to the motor a), a controller 101,
The angular position detection device 102 (corresponding to the motor angular position detection means c) is configured.

The controller 101 inputs the motor angle position signal θ from the motor angle position detecting device 102, the motor power supply voltage VE and the motor angle position command value θB,
Arithmetic device 111 for outputting power transistor control signal
And the motor 1 based on the power transistor control signal
A power transistor unit 110 (corresponding to the power transistor unit b) that supplies a current to 00.

The arithmetic unit 111 includes a motor positioning controller 130 (corresponding to a motor positioning controller e),
And a current amplification control calculation unit 131.

Regarding the motor positioning controller 130, a case where a rear wheel steering control system and the current amplification controller of this embodiment are combined to form a motor positioning controller will be described (see FIG. 3).

The motor positioning control unit 130 compensates for the non-linearity and modeling error of the controlled object by robust compensation, and controls the controlled object to always be a linear model defined by the designer (motor dynamic characteristic compensation). (Corresponding to part j) and a model matching control unit 130b for controlling the response of the controlled object to be the response desired by the designer.
Also, in consideration of the capabilities of elements such as the power transistor unit 110, a motor command current value determination unit 130c that calculates a current command value IB by adding the output IRB of the robust compensator 130a and the output IMB of the model matching control unit 130b.
(Corresponding to the motor input current determination unit f), and outputs the motor current command value IB, the motor dynamic characteristic compensation current IRB, the motor positioning current IMB, and the motor angular position θ to the current amplification control calculation unit 131. .

As shown in FIG. 2, the current amplification control calculation unit 131 includes a motor power supply voltage detection unit 120 (corresponding to the motor power supply voltage detection means d) and a basic duty ratio calculation unit 1.
21 (corresponding to the basic switching time calculation unit h) and DU
It has a TY ratio correction amount calculation unit 122, a power transistor / switching control unit 123 (corresponding to the power transistor / switching control unit i), and a motor back electromotive force estimation unit (corresponding to the motor back electromotive voltage estimation unit g) 124. Is configured.

The motor power supply voltage detector 120 detects the power supply voltage VE of the motor 100. The basic DU
The TY ratio calculation unit 121 uses the motor 10 that has been measured in advance.
The ratio of switching ON in the power transistor switching cycle FW (PWM-DUTY ratio) is calculated from the combined resistance value of the internal resistance of 0 and the ON resistance of the power transistor unit 110 and the motor power supply voltage VE, and the basic of the power transistor unit 110 is calculated. Output stage switching time T _D
Is calculated. The DUTY ratio correction amount calculation unit 122 calculates the correction amount of the basic output stage switching time T _D calculated by the basic DUTY ratio calculation unit 121, and calculates the corrected output stage switching time T _C. The power transistor
The switching control unit 123 controls the switching of the power transistor unit 110 based on the time T _{ON which} is the sum of the basic output stage switching time T _D and the corrected output stage switching time T _C and the motor current command value IB. Output a signal.

The motor back electromotive force estimation unit 124 receives the motor current command value IB, the motor positioning current IMB, and the motor angular position θ, and the transfer characteristics of the controlled object linearized by the robust compensator 130a are shown in FIG. The motor angular velocity estimator as shown is configured, and the motor angular velocity estimated value dθH obtained from the motor angular velocity estimator and the back electromotive force constant KR which is the parameter value of the motor 100 measured in advance.
As a result, the counter electromotive voltage generated by the rotation of the motor 100 is estimated and detected.

In the code used in this embodiment, B represents a target value and H represents an estimated value.

Next, the operation will be described.

[Current Amplification Control Operation Processing] FIG. 5 is a flowchart showing the current amplification control operation processing performed by the arithmetic unit 111 of the controller 101, and each step will be described below.

In step 50, it is judged whether or not it is time to position the motor 100.

In step 51, the motor angular position signal θ
And the motor angular position command value θB are input.

In step 52, the robust compensator 130
At a, the motor dynamic characteristic compensation current IRB is calculated.

In step 53, the motor positioning current IMB is calculated in the model matching control section 130b.

At step 54, the motor current command value IB is determined by adding the motor dynamic characteristic compensation current IRB and the motor positioning current IMB.

In step 55, it is judged whether or not it is time to calculate the power transistor control signal.

In step 56, the motor power supply voltage VE
Is entered.

In step 57, the motor power supply voltage VE
The motor effective voltage estimated value VMH is calculated by using the back electromotive voltage VR estimated as follows.

In step 58, the PWM-DUTY ratio 1
PWM-DUT outputting current value IMAX at 00%
The smaller value is determined as the motor angular velocity estimator input u by comparing the motor current value IM with the Y ratio.

In step 59, the motor power supply voltage VE
And the combined resistance value R _M of the ON resistance of the internal resistor and a power transistor 110 of the motor 100 is previously measured counter electromotive voltage VR and the motor current command value IB, the switching ON of the power transistor switching period F _W The ratio (PWM-DUTY ratio) D _T is calculated.

In step 60, the PWM-DUTY ratio D
_T and the power transistor switching period F _W by the power transistor ON reference time is a basic output stage switching time T _D is calculated, the gate resistor R ₁ and the gate capacitance C in the power transistors ON reference time T _D and the power transistor unit 110 _{From 1} , the gate switching extension time T _C, which is the correction output stage switching time of the power transistor unit 110, is calculated.

In step 61, the power transistor switching time T _ON (= T _D + T) is calculated from the gate switching extension time T _C and the power transistor ON reference time T _D.
C ) is calculated.

In step 62, the motor current command value I
The output direction (forward or reverse) is determined from B, and the power transistor switching control signal is output according to the power transistor switch time T _ON .

[Current Amplification Control Operation] The current amplification control is performed according to the flowchart shown in FIG. 5, and the processing in steps 56 to 62 will be described in detail.

First, a motor angular velocity estimator as shown in FIG. 4 is constructed from the transfer characteristic of the controlled object linearized by the robust compensator 130a. The linearized transfer characteristic of the controlled object is expressed by the following equation. Can be expressed as

Θ = n _mo / (s ² + d _m1 s + d _mo ) (1) where s; differential operator The state equation of the motor angular velocity estimator can be expressed by the following equation.

Dω / dt = AH · ω + Kθ + BH · u (2) dθH = Dω + Hθ (3) However, u: Motor angular velocity estimator input AH = -d _m1 -L BH = Ln _mo K = -L (d _m1 + L) -d _mo H = L dθ H; motor angular velocity estimated value L; constant arbitrarily set by the designer Motor angular velocity estimated value d θ H calculated from the above equation,
The back electromotive force generated by the rotation of the motor 100 is estimated and calculated by the following formula by the back electromotive force constant KR which is the parameter value of the motor 100 measured in advance.

VRH = KR · dθH (4) The maximum angular velocity of the motor 100 occurs because the motor effective voltage VM decreases when the motor angular velocity θ is large. Therefore, the motor angular velocity estimated value dθH is limited by calculating the motor angular velocity estimator input u as follows.

VMH = VE-VR (5) IMAX = VMH / RM (6) When IMAX ≥IM u = IM When IMAX <IM u = IMAX However, VRH; Estimated value of motor back electromotive force VMH; Motor Estimated effective voltage RM; Armature resistance of motor Next, the PWM-DUTY ratio _DT , which is the ratio of switching ON in the power transistor / switching cycle F _W , is calculated by the following formula.

_DT = IB / IMAX (7) However, the power transistor section 11 can be obtained only by the current amplification control method of controlling the motor current by switching the power transistor section 110.
The voltage applied to the motor has a delay on the current application start side due to the delay in the response of the gate voltage V _C due to the gate resistance (including wiring resistance) R _{1 of 0} and the gate capacitance C ₁ and the delay in the switching of the gate. It becomes a waveform, and the motor current command value IB and the motor current do not match.

Therefore, the gate switching time may be extended so that the area is equal to the lacking portion of the motor applied voltage VM with respect to the power transistor switching reference signal due to the influence of the delay.

First, the area S _G of the missing portion of the motor applied voltage VM is calculated by the following equation.

S _G = V _ME * T _D −∫ {1-exp (−t / T _G ) V _ME } dt + V _ME * L _G = V _ME * T _D − [t + exp (−t / T _G ) / T _G ] ₀ ^TD * V _ME + V _ME * L _G = (V _ME / T _G ) {1-exp (-T _D / T _G )} + V _ME * L _G (8) However, T _G = R ₁ * C _1; gate resistor, the time constant due to the gate capacitance _{T D = D T / F W} ; power transistor ON reference time L _G; gate switching delay time therefore, switching extension time T _C of the gates to the following equation (9) Become.

T _C = (1 / T _G ) {1-exp (−t / T _G )} + L _G (9) Here, the values of L _G , R ₁ and C ₁ are the device specifications and experiments. To obtain in advance. Further, the switching extension time T _C may be obtained by a map having the power transistor ON reference time T _D as a function.

Next, the power transistor ON reference time T
_The power transistor switch time T _ON is calculated by the following formula from _D , the gate switching extension time T _C , and the power transistor ON reference time T _D.

T _ON = T _D + T _C (10) Further, the output direction (normal rotation or reverse rotation) is determined from the motor current command value IB, and the power transistor switching control signal is output according to the power transistor switch time T _ON. Is output.

By executing the above arithmetic processing, the motor current command value IB and the motor current can be matched even in the positioning response such that the motor 100 rotates at a high speed without feeding back the motor current. It is possible to achieve current amplification control with high response.

[Simulation Results] FIG. 6 shows the rear wheel rudder angle command value and the rear wheel rudder when the current amplification control device is applied to the motor which is the drive source of the rear wheel rudder angle actuator for the vehicle rear wheel rudder angle control system. It is a simulation comparison figure of each angle, a motor angular velocity, and a motor drive current.

In FIG. 6, the solid line characteristics represent command values, theoretical values and real angular velocity characteristics, the one-dot chain line characteristics represent the characteristics of the present invention, and the dotted line characteristics are determined by the physical characteristics of the motor for estimating the back electromotive force. The characteristic by the conventional method that does not consider the maximum angular velocity is shown.

As a result of this simulation, the characteristics according to the method of the present invention impose a limit on the motor angular velocity,
While the motor angular velocity is suppressed to approximately 300 rad / sec and has a high degree of agreement with the actual angular velocity, the conventional method does not limit the motor angular velocity, and the motor angular velocity reaches approximately 400 rad / sec.

As a result, comparing the motor drive currents, in the case of the conventional method, an unnecessary large current flows in the high motor angular velocity range, whereas in the case of the method of the present invention, the high motor angular velocity range. The current is kept small. That is, by setting a limit on the input u of the motor angular velocity estimator, the back electromotive force of the motor can be estimated more accurately than in the case where no limit is set. In the case of the present invention, the same rear wheel steering angle can be obtained. Even if obtained, unnecessary current was suppressed, power consumption was reduced, and the effectiveness of the present invention was confirmed.

Next, the effect will be described.

(1) In the current amplification control device of the embodiment, the motor positioning current IMB and the motor angular position θ are input, and the maximum angular velocity determined by the physical characteristics of the motor 100 is taken into consideration. Since the motor back electromotive voltage estimation unit 124 that estimates the back electromotive voltage estimates the back electromotive voltage of the motor 100 and uses the estimated back electromotive voltage to control the switching of the power transistor unit 110, the current detection unit and the It is possible to provide a device that does not require a current feedback circuit and is cost-effective, and that can suppress power consumption by an appropriate motor drive current when the motor 100 operates in the maximum rotation range.

(2) The motor positioning control unit 130 includes a robust compensator 130a for compensating the non-linearity and modeling error of the controlled object by the robust compensation so that the controlled object always becomes the linear model defined by the designer. The motor current command value determination unit 130c is provided in the robust compensator 1.
30a and the output IMB of the model matching control unit 130b are added together to calculate a current command value IB, and the motor back electromotive force estimation unit 124 is set to a dynamic characteristic and a current command that are stabilized by the robust compensator 130a. Value IB
Since the unit for estimating the back electromotive force is used to improve the estimation accuracy of the motor back electromotive force, the motor 100
It is possible to obtain a positioning response of the motor 100 that substantially matches the design target even during high-speed rotation of the motor, which is affected by the dynamic characteristics of 1.

(3) Since the motor angular velocity estimated value dθH is limited by limiting the motor angular velocity estimator input u, the motor angular velocity estimated dθH can be easily limited.

Although the embodiments have been described above with reference to the drawings, the specific configuration is not limited to the embodiments, and modifications and additions within the scope of the present invention are included in the present invention. Be done.

For example, in the embodiment, the rear wheel steering angle is controlled 4
Although the application example to the motor drive current control section of the WS system is shown, the present invention can be applied to the drive current control section of various systems that control the motor drive current other than the 4WS system.

[0076]

According to the first invention of claim 1,
In a current amplification control device that controls the motor current based on the current command value, the motor positioning current and the motor angular position are input, and the back electromotive force of the motor is estimated in consideration of the maximum angular velocity determined by the physical characteristics of the motor. The motor back electromotive force estimation unit, the basic switching time calculation unit that inputs the motor power supply voltage and the motor back electromotive voltage, and determines the basic switching time of the power transistor unit by the impedance of the motor and the power transistor unit measured in advance. Since the device is equipped with a power transistor switching control unit that controls the switching of the power transistor unit based on the input current and the basic power transistor switching time, it does not require a current detection unit or a current feedback circuit and is cost effective. In favor of , Motor effect is obtained that it is possible to provide a device which can suppress power consumption low by proper motor drive current when operating at the maximum rotation range.

According to a second aspect of the present invention, in the current amplification control device according to the first aspect, a motor dynamic characteristic compensator for calculating a motor input current for keeping the dynamic characteristic of the motor constant. The motor input current determination unit is a unit that inputs the motor positioning current and the motor dynamic characteristic compensation current to determine the motor input current, and the motor back electromotive force estimation unit is stabilized by the motor dynamic characteristic compensation unit. In addition to the above effects, the estimation accuracy of the motor back electromotive force can be improved because it is a part that estimates the back electromotive force using dynamic characteristics and motor positioning current, and it is a design target even when the motor rotates at high speed. The effect that the positioning responses of the motors that substantially match can be obtained.

According to the third aspect of the present invention, since the limitation of the motor angular velocity estimation in the motor back electromotive force estimation section is realized by an estimator that limits the input, in addition to the above effects, It is possible to obtain an effect that the estimation of the motor angular velocity can be easily performed.

[Brief description of drawings]

FIG. 1 is a claim correspondence diagram showing a current amplification control device of the present invention.

FIG. 2 is a block diagram showing a current amplification control device according to an embodiment of the present invention.

FIG. 3 is a detailed block diagram of a motor positioning controller of the embodiment apparatus.

FIG. 4 is a control block diagram of a motor angular velocity estimator of a motor back electromotive force estimation unit of the embodiment apparatus.

FIG. 5 is a flowchart showing a flow of a current amplification control processing operation performed by the arithmetic unit of the controller according to the embodiment of the present invention.

FIG. 6 is a simulation comparison characteristic diagram of a method of the present invention and a conventional method in rear wheel steering angle control by driving a motor.

FIG. 7 is a block configuration diagram showing a conventional current amplification control device.

[Explanation of symbols]

 a motor b power transistor section c motor angular position detection means d motor power supply voltage detection means e motor positioning control section f motor input current determination section g motor back electromotive force estimation section h basic switching time calculation section i power transistor switching control section j Motor dynamic characteristic compensation unit

Claims (3)

[Claims] 1. A power transistor section for supplying a current to a motor, a motor-angular position detecting means for detecting an angular position of the motor, a motor power source voltage detecting means for detecting a power source voltage of the motor, and a designer's request. A motor positioning control unit that calculates a motor input current for positioning and responsiveness of the motor, a motor input current determination unit that inputs the motor positioning current and determines the motor input current, the motor positioning current and the motor A motor back electromotive force estimation unit that inputs an angular position and estimates the back electromotive force voltage of the motor in consideration of the maximum angular velocity determined by the physical characteristics of the motor; and inputs the motor power supply voltage and the motor back electromotive force voltage. However, the impedance of the motor and the power transistor measured in advance is used for the power transition. A basic switching time calculation unit that determines the basic switching time of the star unit, the motor input current and the basic power transistor
And a power transistor switching control unit that controls switching of the power transistor unit based on a switching time. 2. The current amplification control device according to claim 1, further comprising: a motor dynamic characteristic compensating unit that calculates a motor input current for always keeping the dynamic characteristic of the motor constant; The motor positioning current and the motor dynamic characteristic compensation current are input, and the motor input current is determined by the motor back electromotive force estimation unit, and the motor dynamic characteristic compensation unit stabilizes the dynamic characteristic and the motor positioning current. A current amplification control device, wherein the current amplification control device is a unit that estimates a back electromotive voltage using the. 3. The current amplification control device according to claim 2, wherein the limitation of the motor angular velocity estimation in the motor back electromotive voltage estimation unit is realized by an estimator that limits the input. .