JP3873006B2 - Brushless motor control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a motor control device that controls driving by a current passing pattern to a three-phase coil, generally called a DC brushless motor.
[0002]
[Prior art]
In order to drive the DC brushless motor, it is necessary to detect the phase (position) of the rotor and switch the energization of the coil in accordance with the phase of the rotating rotor. In general, a 120 ° energization method that is easy to control is known.
This is a method of energizing two phases out of three phases, but a brushless motor is generally provided with three hall sensors as phase detection means. The signal changes every time the rotor phase changes by 60 °. Therefore, the energization pattern is changed according to the signal change of the Hall sensor.
FIG. 6 is an explanatory diagram showing a detection state by the Hall sensor and an energization state.
As shown in this figure, the Hall sensor signals Hs1, Hs2, and Hs3 output from the three Hall sensors are those in which the output of Hi / Lo is switched by the 180 ° movement of the rotor. ° The output varies with different phases. Therefore, the phase of the rotor can be detected every 60 ° as shown on the basis of the change in the output of each sensor. The vertical axis indicating the change every 60 ° is referred to as a position signal Ps.
Corresponding to the input of the position signal Ps corresponding to the phase of the rotor, the current is switched between +, 0, and − in three phases of U phase, V phase, and W phase as shown by solid lines in the figure. Then, the energized phase is changed.
[0003]
By the way, the driving force can be most efficiently applied to the rotor when the current flows in the orthogonal direction with respect to the magnetic flux.
On the other hand, in the 120 ° energization method described above, the current is switched to the energized state every 60 °, so that the current flows in the orthogonal direction with respect to the magnetic flux only at one angle in the rotation range of 60 °.
[0004]
Therefore, a sine wave driving method based on vector control is known as a method for driving the brushless motor more efficiently. In this driving method, a sinusoidal characteristic as indicated by a two-dotted line in FIG. 6 with respect to the three phases U phase, V phase, and W phase so that the current always flows in a direction orthogonal to the phase of the rotor It is a method of energizing with. If energization is performed with a sine wave as shown, the rotor can be driven efficiently.
[0005]
[Problems to be solved by the invention]
However, according to the sine wave driving method described above, energization is performed based on the phase of the rotor, and therefore it is necessary to accurately detect the phase of the rotor.
Therefore, an expensive position sensor for detecting the phase of the rotor is required.
[0006]
On the other hand, as described above, a technique for estimating the rotor phase using an inexpensive Hall sensor that can accurately detect the rotor phase only every 60 ° is also known. Such a problem arises.
First, rotor phase estimation using a Hall sensor will be described. The position signal Ps by the hall sensor is switched every 60 ° as indicated by Ps1 to Ps4 in FIG. Therefore, the angular velocity of the rotor can be estimated by measuring the switching interval time Δt.
Angular velocity (estimated value) ω = 60 ° / (switching interval time Δt)
That is, as shown in FIG. 7, since the position signal Ps is generated every time the output of the hall sensor is switched, the time Δt from when the position signal Ps is generated until the next position signal Ps is generated is measured. The angular velocity ω of the rotor in the meantime can be obtained.
Therefore, every time the position signals Ps1, Ps2, and Ps3 are input, an accurate phase is interrupted and calculated based on the absolute value.
Further, the phase of the rotor is estimated based on the angular velocity until the next position signal Ps is input after the position signal Ps is input. That is, for example, from the time when the current position signal Ps2 is input to the time when the next position signal Ps3 is input, from the switching interval time Δt1 between the previous position signal Ps1 and the current position signal Ps2, the previous angular velocity ω1. And the estimated phase value after the current position signal Ps2 is input is obtained from the previous angular velocity ω1 and the elapsed time. In the illustrated example, since the control cycle time is 0.25 (msec), the displacement amount is obtained by multiplying the previous angular velocity ω1 by the control cycle time, and the absolute phase of the rotor when the position signal Ps2 is obtained is obtained. The phase estimation value is obtained by adding this displacement amount to the value.
[0007]
However, as shown in FIG. 7, since the angular velocity ω is not constant, the actual angular velocity of the rotor has decreased, as shown in the figure, such that the switching interval time Δt2 after the switching interval time Δt1 is long. In this case, the phase estimation value is shifted ahead of the actual phase, and the phase estimation value is already a value that the next position signal Ps3 should generate, but the actual phase has not reached that phase. Become.
On the contrary, when the angular velocity of the actual rotor increases such that the switching interval time Δt3 after the switching interval time Δt2 is short, the phase estimation value is shifted from the actual phase, and the phase estimation value Although the next position signal Ps4 has not yet reached the phase to be generated, the next position signal Ps4 is input.
[0008]
As described above, when the actual phase and the phase estimation value are largely separated from each other, the energization direction with respect to the magnetic flux is deviated from the efficient direction, and torque shortage occurs. In particular, when the actual angular velocity is slower than the estimated angular velocity, such as between the position signals Ps2 and Ps3, this phase shift may be 60 ° at the worst.
The effect on the torque output due to such a phase shift is cos (shift angle) times. When the phase is shifted by 60 °, the output torque is cos 60 ° times = ½ times.
[0009]
The present invention has been made paying attention to such a conventional problem, and the phase signal is measured by measuring the change and time of the position signal while using an inexpensive Hall sensor used in the 120 ° energization method. In a brushless motor control apparatus that performs estimation of the above, a brushless motor control apparatus that can suppress the deviation width between the actual phase and the phase estimation value to be small and can be driven more efficiently than the conventional one is inexpensive. The purpose is to do.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, in the phase estimation means for estimating the phase of the rotor based on the detection of the phase detection means and the passage of time, the phase estimation value is detected by the phase detection means from now on. If the phase corresponding to the next detection phase has been reached but the next detection phase is not detected by the phase detection means, the phase estimation value is returned by a predetermined amount from the next detection phase to the current detection phase. Was configured to execute.
[0011]
Therefore, when the rotation of the rotor is delayed as compared with the previous time, the phase estimation unit performs the current phase estimation based on the previous angular velocity, and as a result, the phase estimation value is shifted from the actual phase.
As described above, when the actual phase is delayed and the deviation width from the phase estimation value is increased, the energization direction is deviated from the optimum direction with respect to the rotor phase, and the torque efficiency is deteriorated.
On the other hand, in the present invention, when the phase estimation value reaches the next detection phase that is the phase detected by the phase detection means next, the phase estimation value return processing is executed.
As a result, the phase estimation value moves toward the actual phase, and the gap between the phase estimation value and the actual phase is narrowed. As a result, the adverse effect on the torque output is suppressed and the torque efficiency can be improved.
Thereafter, when the actual phase of the rotor reaches the next detection phase, the phase detection means detects this, and the phase estimation means starts estimation from this next detection phase.
[0012]
As described above, according to the present invention, it is possible to suppress the deviation width between the actual phase and the phase estimation value to be smaller than the conventional one while using an inexpensive detection unit that detects in increments of a predetermined angle as the phase detection unit. However, it is possible to provide a brushless motor control device that can drive more efficiently than the conventional one.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
The brushless motor control device according to the embodiment of the present invention will be described below.
FIG. 1 is an overall system diagram showing an electrohydraulic power steering apparatus to which a brushless motor control apparatus according to an embodiment of the present invention is applied.
In the figure, reference numeral 1 denotes a handle, which is connected to a rack and pinion 3 via a joint 2. As a result, the shaft 4 connected to the front wheel (not shown) is displaced in the left-right direction (X direction) in conjunction with the operation of the handle 1 to perform steering.
Further, the shaft 4 is provided with a hydraulic cylinder 5. The hydraulic cylinder 5 gives assist force to the shaft 4 by supplying and discharging fluid such as oil to the left and right chambers 51 and 52 according to the driving of the pump 6.
The driving of the pump 6 is controlled by rotation of a brushless motor (hereinafter referred to as a motor) 7. Further, the rotation of the motor 7 is controlled by the control unit 8.
[0014]
The control unit 8 inputs a torque sensor signal Vt from a torque sensor 9 provided in the middle of the joint 2, and receives a sensor signal Ss from a position sensor 71 as a phase detection means provided in the motor 7. Then, the phase estimation is performed and the energization to the motor 7 is controlled, which corresponds to the phase estimation means and the energization control means in the claims.
The position sensor 71 includes three hall sensors (not shown) as described in the prior art, and the hall sensors each time the phase of the rotor outside the figure of the motor 7 changes by 180 °. While the Hi / Lo of the signal Ss is switched, the Hall sensor signals Hs1, Hs2, and Hs3 whose phases are shifted by 120 ° are output.
In FIG. 1, Th is a steering torque, θh is a steering angle, Xs is a rack stroke, Tp is a pinion gear torque, θp is a pinion gear angle, Fps is an assist reaction force, Vt is a torque sensor signal, Imu, Imv, Imw. Is a motor drive command current (to U phase, V phase, W phase), Vmu, Vmv, Vmw is a motor drive command voltage (to U phase, V phase, W phase), Tm is a motor torque, θm is Motor phase, θSm is a motor phase estimation value, Δθ is a phase change estimation value for each control cycle, and Ppl and Ppr are pump discharge pressures.
[0015]
Next, FIG. 2 is a circuit diagram showing the control unit 8 and the motor drive circuit 72.
That is, the control unit 8 is provided with a current command value calculator 81 for calculating a current command value so that the current command value increases as the detected torque increases in response to a signal from the torque sensor 9. Further, an angular velocity estimator 82 for estimating the angular velocity of the rotor (not shown) based on the input from the position sensor 71 and a phase estimator 83 for estimating the phase of the rotor are provided as will be described later. Further, a current detector 84 that detects a motor drive command current output to the motor 7 is provided. The current controller 85 outputs a control signal to the motor drive circuit 72 based on signals from the current command value calculator 81, the angular velocity estimator 82, the phase estimator 83, and the current detector 84. .
[0016]
The motor drive circuit 72 is provided in the motor 7 and includes a PWM generator 73 that generates a PWM current signal by a control signal. The motor drive circuit 72 is used for vector control toward the U phase, V phase, and W phase. The motor drive command current is supplied.
[0017]
Next, FIG. 3 shows the processing flow of the angular velocity estimation of the motor 7 by the angular velocity estimator 82 of the control unit 8 and the phase estimation by the phase estimator 83, that is, the phase estimation and phase return processing by the phase estimation means of the claims. It is a flowchart to show.
Before describing with this flowchart, the phase estimation method will be described.
As described above with reference to FIG. 6, the position sensor 71 changes the phase of the rotor every 60 ° by the position signal Ps obtained based on Hi / Lo switching of the Hall sensor signals Hs1, Hs2, and Hs3 from the position sensor 71. Can be detected.
Therefore, every time the position signal Ps is obtained, the current rotor phase is updated based on the absolute value. This update is executed by an interrupt process every time the position signal Ps is input, and the rotor phase obtained by the interrupt process is an actual phase.
In contrast, during the period from when the position signal Ps (n) is input until the next position signal Ps (n + 1) is switched, the phase is estimated based on the measurement of the switching interval time Δt (n). As described with reference to FIG. 7, this estimation is performed by obtaining the previous angular velocity ω1 by the angular velocity estimator 82 based on the previous switching interval time Δt1, and estimating the motor position with the passage of the current time based on the previous angular velocity ω1. I do.
[0018]
Next, a description will be given step by step based on the flowchart of FIG.
The process shown in the flowchart of FIG. 3 is executed every time the position signal Ps (n) is input.
First, in step 101, it is determined whether or not the motor 7 is rotating forward, the process proceeds to step 102 at the time of forward rotation, and to step 107 at the time of reverse rotation.
In this embodiment, the rotation direction of the motor 7 is detected by a motor drive command current detected by the current detector 84. However, the rotation direction of the motor 7 is determined by the steering angle θh detected by a steering angle sensor (not shown). It can also be detected.
[0019]
Next, in step 102, a phase estimation value θSm is calculated.
This calculation is obtained by adding the phase change amount Δθ for each control cycle to the previous value of the phase estimation value θSm.
In other words, taking the section between the position signals Ps2 and Ps3 as an example in FIG. 7, first, the absolute value of the motor position (in this case, 60 °) is obtained at the time when the position signal Ps2 is obtained. The phase change amount Δθ from the position 60 ° is obtained by multiplying the previous angular velocity ω1 obtained based on the previous switching time by the control cycle time (in this example, 0.25 sec). Therefore, the first phase change amount Δθ1 is obtained at ω1 × 0.25 sec.
When the next control cycle elapses, Δθ2 = ω1 × 0.25 × 2 is obtained, and the phase change amount Δn = ω1 × 0.25 × n after elapse of n control cycles.
Therefore, the phase estimation value θSm is initially obtained by adding the phase change amount Δθ1 to the phase absolute value at the time of switching (in this case, 60 °), and from the next time, the phase change amount Δθn is added to the previous value of the phase estimation value θSm. It is obtained by adding.
[0020]
In the next step 103, it is determined whether or not the phase estimation value θSm is equal to or greater than the value obtained by adding 60 ° (deg) to the phase absolute value at the time of switching. If this value is not reached, the process returns to step 102. The phase estimated value θSm is calculated. On the other hand, when this value is reached, the routine proceeds to step 104, where the phase estimated value returning process, which is a process characteristic of the present embodiment, is executed.
That is, every time the phase estimation value θSm is obtained in step 102, the process proceeds to step 103, where the phase estimation value θSm is the phase at which the next position signal is obtained (see the above-described figure). 7 In this example, it is determined whether or not the phase estimation value θSm exceeds the phase at which the next position signal Ps3 is obtained (120 °). Until the phase estimation value θSm becomes the phase at which the next position signal is obtained, The processes in steps 102 and 103 are repeated.
[0021]
Next, the phase estimation value return process performed in step 104 will be described.
In this phase estimation value return processing, the phase estimation value θSm is obtained by adding 60 ° to the phase absolute value at the time of switching (in the above-described estimation from the absolute value 60 ° to 120 °, 120 ° is The return change amount Δθm is subtracted from the above. In this embodiment, a value (Δθn) obtained by multiplying the value obtained based on the previous angular velocity ω by the control cycle time is used as the return change amount Δθm, as in step 102 described above. However, the present invention is not limited to this, and a preset value may be used.
[0022]
In the next step 105, the phase estimated value θSm obtained in the phase estimated value return process in step 104 is a value obtained by adding 30 ° to the phase absolute value (60 ° in the above example) at the time of switching (that is, the absolute value described above). It is determined whether or not it is an intermediate value that is ½ in the estimation from the value 60 ° to 120 °, and this value is hereinafter referred to as an intermediate value). Then, the phase estimation value returning process is further performed.
In Step 106, the phase estimation value θSm is fixed to a value obtained by adding 30 ° to the phase absolute value at the time of switching (60 ° in the above example).
That is, the phase estimated value θSm that has once reached the phase absolute value (120 ° in the above example) that should be obtained next at the time of step 103 is changed to the phase absolute value at the time of switching by the processing of steps 104 to 106. It is returned to a value obtained by adding 30 ° to (in the above example, 60 °) (90 ° in the above example), and finally the phase absolute value at the time of switching (in the above example, 60 °). It is fixed at a value obtained by adding 30 °.
[0023]
Next, the processing in steps 107 to 111 is a flow in the case of displacement in the reverse direction (the direction that appears as a numerical value) with respect to the processing in steps 102 to 106, and the concept is the same as in steps 102 to 106. Since there is, it explains briefly.
In step 107, the phase estimation value θSm can be obtained by subtracting the phase change amount Δθn for each control cycle from the previous phase estimation value θSm.
That is, the phase estimation value θSm is obtained by first subtracting the phase change amount Δθ1 from the phase absolute value at the time of switching, and subtracting the phase change amount Δθn from the previous value of the phase estimation value θSm from the next time.
[0024]
In the next step 108, it is determined whether or not the phase estimated value θSm is equal to or smaller than the value obtained by subtracting 60 ° from the phase absolute value at the time of switching. If not smaller than this value, the process returns to step 107 to return to the phase estimated value. If θSm is calculated, on the other hand, if the value is equal to or smaller than this value, the routine proceeds to step 109, where the phase estimation value returning process is executed.
Next, in step 109, a phase estimation value return process, which is a process of adding the return change amount Δθm to the phase estimated value θSm obtained by subtracting 60 ° from the phase absolute value at the time of switching, is executed. Also in this case, the return change amount Δθm may be a value obtained by multiplying the value obtained based on the estimated angular velocity value ω by the control cycle time, as in step 107 described above, or A preset value may be used.
[0025]
In the next step 110, it is determined whether or not the phase estimated value θSm obtained by the phase estimated value returning process in step 109 is equal to or larger than the value obtained by subtracting 30 ° from the phase absolute value at the time of switching. If not, the process returns to step 109 to further perform a phase estimation value return process.
In step 111, the phase estimation value θSm is fixed to a value obtained by subtracting 30 ° from the phase absolute value at the time of switching.
[0026]
The process shown in the flowchart of FIG. 3 described above is interrupted whenever the position signal Ps is input as described above.
Therefore, when the phase estimation value θSm precedes the actual phase, the phase estimation value return processing after step 104 is executed, and even when the phase estimation value return processing is executed, the intermediate value If the next position signal is input before the time reaches, the next interrupt processing is performed.
That is, in FIG. 7, when the current switching interval time Δt2 is longer than the previous switching interval time Δt1, the phase estimated value θSm obtained based on the angular velocity estimated value ω1 is calculated before the next position signal Ps3 is input. The absolute value (120 °) when the position signal Ps3 is input is reached. Therefore, in such a case, the phase estimation value returning process is executed.
[0027]
On the other hand, when the switching interval time Δt3 is shorter than the previous switching interval time Δt2 as after the position signal Ps3 is input, the actual phase precedes the phase estimation value θSm, and this phase estimation is performed. Before the value θSm reaches the absolute value (180 °) when the next position signal Ps4 is input, the position signal Ps4 is input, and the next interruption process is performed as an estimation from the absolute value 180 ° again. Will be.
[0028]
Next, the operation of the embodiment will be described.
FIG. 4 is a time chart showing a conventional operation example in which the phase estimation value returning process is not executed, that is, FIG. 5 is a time chart showing an operation example when the phase estimated value returning process is executed. In the operation examples shown in these time charts, the handle is cut in the + direction.
In both figures, the steering wheel is cut in the section (a), and as a result of the actual angular velocity decelerating due to load fluctuations, the actual displacement in the next section (b) as in the section (Ps2-Ps3) in FIG. In contrast, the phase estimation value advances to show a phase shift. That is, at the time point indicated by t11 in this section (b), the phase estimation value reaches a value corresponding to the actual phase (position signal Ps12) detected next time, and thereafter the phase estimation is performed until the position signal Ps12 is actually obtained. This value is used as the value.
When the phase shift occurs in this section (b), the torque efficiency by the motor 7 is deteriorated and sufficient torque cannot be obtained. As a result, in the section (b) in FIG. Torsion bar torque increase). Furthermore, since the current command value is increased in response to the increase in the torsion bar torque, the motor torque increases and the phase shift starts to decrease.
Next, when the position signal Ps12 is obtained, an actual phase is obtained. However, in this section (c), an excess current is generated due to a phase shift in the previous section (b). Assists and the handle becomes lighter than intended (decreasing torsion bar torque). Therefore, in order to suppress the assist force, the current value is lowered to cope with it. However, since the torque change in this section (c) is abrupt, it converges while repeating increase / decrease (hunting) in the subsequent section (d).
When such torque fluctuation occurs, the driver feels uncomfortable with steering, and furthermore, such torque fluctuation may occur continuously. In this case, the uncomfortable feeling increases.
[0029]
On the other hand, in FIG. 5 showing the operation example of the present embodiment, in the section (b), the phase estimation value θSm becomes the phase absolute value + 60 ° at the time of switching due to the phase shift between the actual phase and the phase estimation value. When the next position signal (Ps12) is not generated at the time (t11), the phase is determined based on the processing of Step 101 → 102 → 103 → 104 (in the case of the left and right reverse, Step 101 → 107 → 108 → 109). The estimated value return process is executed, and the phase estimated value θSm decreases. Further, this decrease ends when the estimated phase value θSm becomes a value obtained by adding 30 ° to the phase absolute value at the time of switching (this is set as an intermediate value), and is maintained at this intermediate value.
As described above, as a result of returning the phase estimation value θSm to the intermediate value, in the section (b) in the figure, the phase estimation value θSm approaches the actual phase indicated by the dotted line, and then crosses the actual phase and is smaller than the actual phase. It is a value. In the example of this time chart, the estimated phase value θSm is returned to the intermediate value by the return control, but this is a problem of the timing at which the next position signal Ps12 is input and the actual phase is obtained. If the position signal Ps12 is obtained at a timing earlier than that shown in the chart, the phase estimated value return processing may be terminated before the phase estimated value θSm reaches the intermediate value.
[0030]
As described above, in the example of FIG. 5, the phase estimation value θSm is finally maintained at the intermediate value that exceeds the actual phase and is smaller than the actual phase. The intermediate value is reached after crossing the point where the phase estimation value θSm and the actual phase coincide with each other, and this intermediate value is the conventional 120 ° energization with respect to the motor phase at the next switching timing. Efficiency equivalent to that of the law can be obtained. That is, the intermediate position returned by 30 ° from the absolute value at which the next position signal Ps12 is input is 30 ° even if it is shifted to the maximum on either the plus or minus side with respect to the actual phase. °. Therefore, the torque output is a torque obtained by cos 30 ° (≈0.87) times, which is compared with cos 60 ° (= 1/2) times, which is the case where the phase is maximally shifted in the prior art. Torque can be obtained efficiently.
[0031]
For this reason, the torsion bar torque is compared with the case where the absolute value when the next position signal Ps12 is input as in the prior art of FIG. 4 is maintained as the phase estimation value θSm as indicated by the dotted line in the figure as in the prior art. As the value becomes smaller, the torque current command value also becomes smaller, so that it is possible to prevent the conventional lack of assist force. Thereby, generation | occurrence | production of the overcurrent like the past is prevented.
[0032]
Thereafter, as shown in the section (c) of FIG. 5, when the position signal Ps12 is input and the actual phase is obtained, the torque current command value has been increased to compensate for the lack of assist until then. The torque current command value will be reduced because it is judged as an overcurrent, but this reduction will be less than in the conventional case, and the torsion bar command value is a target value as compared to the conventional example shown by the dotted line as shown in the figure. Converge quickly.
Thereby, in this Embodiment, generation | occurrence | production of the torque fluctuation like the past can be suppressed.
[0033]
As described above, while using an inexpensive Hall sensor that detects in 60 ° increments as the phase detection means, it is possible to suppress the deviation width between the actual phase and the phase estimation value to be smaller than the conventional one. It is possible to drive more efficiently, and to suppress torque fluctuations in the power steering device and improve torque control quality.
[0034]
(Another embodiment)
As mentioned above, although embodiment of this invention has been described, this invention can be actualized in another embodiment as follows. In the following other embodiments, the same operations and effects as those of the above embodiment can be obtained.
For example, in the embodiment, an example in which the brushless motor control device of the present invention is applied to a power steering device has been described. However, any device that controls a motor phase by a Hall sensor can be applied to other devices. .
Further, in the phase estimation value return control, in the embodiment, the next position signal is returned to the intermediate position returned by 30 ° from the absolute value to which the next position signal is input. However, how far this is returned is not limited to this, You may set to the value close | similar to the absolute value when the next position signal is obtained rather than the intermediate value shown in embodiment.
In the embodiment, as the phase detection means, means for detecting the rotor phase in 60 ° increments by the Hall sensor is shown, but this angle is not limited to 60 °.
[0035]
(Technical thought other than claims)
Further, technical ideas other than the claims that can be grasped from the above embodiment will be described below together with the effects thereof.
[0036]
B) In the brushless motor control device according to claim 1,
A brushless motor control device, wherein the energization control means is configured to energize a sine wave to each phase of the coil so as to energize in a direction substantially orthogonal to the phase of the rotor.
As described above, since the current is supplied in the substantially orthogonal direction according to the phase of the rotor, the torque can be obtained efficiently.
[0037]
(B) In the brushless motor control device according to claim 2,
A brushless motor control device, wherein the phase estimation means is configured to return the phase based on the previous angular velocity when returning to the intermediate phase in the phase estimation value return processing.
When the phase estimation value precedes the actual phase, the phase return is performed based on the previous angular velocity, thereby suppressing a phase shift due to excessive return and torque fluctuation due to a sudden phase change.
[Brief description of the drawings]
FIG. 1 is an overall system diagram showing a power steering device to which a brushless motor control device according to an embodiment of the present invention is applied.
2 is a circuit diagram showing a control unit 8 and a motor drive circuit 72 according to Embodiment 1. FIG.
FIG. 3 is a flowchart showing a processing flow of phase estimation and phase return processing by phase estimation means in the brushless motor control apparatus of the embodiment;
FIG. 4 is a time chart showing a conventional operation example in which the phase estimation value return processing is not executed.
FIG. 5 is a time chart showing an operation example when a phase estimation value returning process is executed.
FIG. 6 is an explanatory diagram showing a detection state and an energization state by a hall sensor.
FIG. 7 is an explanatory diagram of phase estimation.
[Explanation of symbols]
7 Brushless motor
8 Control unit (phase estimation means, energization control means)
9 Torque sensor
71 Position sensor (phase detection means)
θSm Phase estimate
ω Previous angular velocity

Claims (2)

A brushless motor having a three-phase coil;
Phase detection means for detecting the phase of the rotor of the brushless motor in increments of a predetermined angle;
Based on the detection of this phase detection means and the passage of time, the phase of the rotor is estimated, and the phase detection means is displaced from the previous detection phase that is the previous detection phase to the current detection phase that is the current detection phase. Phase estimation means for obtaining a previous phase angular velocity from the time required for, and obtaining a phase estimation value by assuming that the rotor is rotating at the previous angular velocity during the next detection phase detected next time from the current detection phase;
Energization control means for controlling energization to the coil based on estimation by the phase estimation means and detection of the phase detection means;
In a brushless motor control device comprising:
The phase estimation means detects the phase estimation value from the next detection phase this time when the phase detection value reaches the value corresponding to the next detection phase but the next detection phase is not detected by the phase detection means. A brushless motor control device characterized in that a phase estimation value return process for returning a predetermined amount to the phase side is executed. In the brushless motor control device according to claim 1,
The phase detection means is means for detecting a phase in 60 ° increments,
The brushless motor control device, wherein the phase estimation means is configured to gradually return a phase toward an intermediate phase that is a phase returned by 30 ° from the next detection phase in the phase estimation value return processing.

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