JPH08228496A - Driver of brushless motor - Google Patents

Abstract

PURPOSE: To provide a driver for a brushless motor, which can control the phase changover of the brushless motor even in the case where control cycle is short. CONSTITUTION: Based on the change of the rotation signal being outputted from a revolution sensor RS, responding to the rotational position of the motor shaft MS of a brushless motor BM, the phase changeover pattern to an exciting coil EC is changed over with a phase changeover control means PC at every specified interval, and a phase changeover signal is outputted to an exciting means EM. On the other hand, interruption is performed by an interruption means IC, according to a revolution signal, and even in case where a change occurs in the revolution signal, for example, earlier than the specified interval, this drivers stops the output of the phase changeover signal by the phase changeover control means PC, and also, outputs a changeover signal from the interruption control IC to the exciting means EM. The exciting coil is supplied with a current, according to any phase changeover signal among these.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless motor driving device, and more particularly to a brushless motor driving device suitable for a rear wheel steering device of a vehicle.

[0002]

2. Description of the Related Art Conventionally, various motors are known as so-called brushless motors having no brush. For example, Japanese Unexamined Patent Publication (Kokai) No. 6-261588 discloses a motor according to a change in output of a rotation sensor for detecting rotation of a motor shaft. Then, the phase switching control means switches the phase switching signal pattern, the phase switching control means outputs a phase switching signal to the switching element in accordance with the phase switching signal pattern, and the switching element is driven according to the phase switching signal. A brushless motor that supplies a current to an exciting coil is disclosed. And, in the same publication, while conducting any one of the switching elements sequentially by the conducting means, the current of the exciting coil is measured every time the conducting means conducts, and when the current of a predetermined value or more is detected, it is determined to be abnormal. An abnormality detection device has been proposed.

[0003]

In the device described as the embodiment in the above publication, the phase switching control is performed every 5 ms on the basis of the signal from the magnetic pole sensor, so that it is shorter than 5 ms. If the motor rotates at time intervals, the signal from the magnetic pole sensor will not be processed properly. The publication suggests that the phase switching control can be performed in the interrupt routine when the control cycle is thus fast. However, even if the phase switching control is simply performed within the interrupt routine, interference will occur with the main routine.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a brushless motor drive device capable of smoothly performing phase switching control of a brushless motor even when the control cycle is short.

[0005]

In order to achieve the above object, the present invention has an exciting coil EC of at least three phases as shown in the outline of the configuration in FIG. 1 and excites the exciting coil EC. A brushless motor BM having a motor shaft MS that rotates according to the state, a rotation sensor RS that outputs a rotation signal according to the rotation position of the motor shaft MS, and a change in the rotation signal at predetermined time intervals. Excitation coil E
In a brushless motor drive device, a phase switching control means PC for switching a phase switching signal pattern for C to output a phase switching signal, and an excitation means EM for supplying a current to an exciting coil EC according to the phase switching signal. An interrupt control means IC is provided for performing an interrupt process according to the rotation signal, stopping the output of the phase switch signal by the phase switch control means PC, and outputting the phase switch signal to the exciting means EC. It is a thing.

Further, as described in claim 2, it is preferable to include an abnormality determining means AB for making an abnormality determination based on the rotation signal of the rotation sensor RS and the interrupt signal of the interrupt control means IC.

[0007]

According to the brushless motor driving device shown in FIG. 1, the brushless motor B has the above-mentioned structure.
A rotation signal is output from the rotation sensor RS according to the rotation position of the motor shaft MS in M. In accordance with this change in the rotation signal, the phase switching control means PC switches the phase switching signal pattern for the exciting coil EC at predetermined time intervals, and the phase switching signal is output to the exciting means EM. On the other hand, the interrupt control means IC performs an interrupt process according to the rotation signal, and, for example, when the rotation signal changes earlier than the predetermined time interval, the phase switching control means PC outputs the phase switching signal. And the phase control signal is output from the interrupt control means IC to the excitation means EM. Thus, in accordance with the phase switching signal output from either the phase switching control means PC or the interrupt control means IC, the excitation means EM.
By this, a current is supplied to the exciting coil EC, and the motor shaft MS rotates.

Further, in the brushless motor drive device having the abnormality determining means AB as described in claim 2, since the abnormality determination is performed based on the rotation signal and the interrupt signal, the rotation sensor RS controls the interrupt. Even if an abnormality occurs in the portion reaching the means IC, this can be surely discriminated.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which a brushless motor drive device of the present invention is mounted on a rear wheel steering device of a vehicle will be described below with reference to the drawings. FIG. 2 shows an overall configuration of a vehicle equipped with a rear wheel steering device. Front wheels 13 and 14 are steered by a front wheel steering mechanism 10 in accordance with a turning operation of a steering wheel 19. The front wheel steering mechanism 10 includes the front wheels 1
A front wheel steering angle sensor 17 such as a potentiometer for detecting the steering angle amounts of 3 and 14 is provided, and the measurement data thereof is supplied to the electronic control unit 20.

Further, a yaw rate sensor 8 is provided, whereby a changing speed of a vehicle rotation angle (yaw angle) around a vertical axis passing through the center of gravity of the vehicle, that is, a yaw angular velocity (yaw rate).
Is detected, and the electronic control unit 20 is operated as yaw rate γ.
Is supplied to. Further, a vehicle speed sensor 9 for detecting the speed of the vehicle is provided, and a signal representing the vehicle speed Vs of the output is supplied to the electronic control unit 20. As the vehicle speed sensor 9, a pair of sensors may be used to detect the vehicle speed in two systems, and the average value or the maximum value thereof may be output as the vehicle speed Vs. Can be detected.

A rear wheel steering mechanism 18 is connected to the rear wheels 15 and 16 and steered according to the rotation of a three-phase brushless motor (hereinafter, simply referred to as a motor) 12. Motor 1
A magnetic pole sensor 61 for detecting the rotation angle is provided at the axial end portion of 2. The magnetic pole sensor 61 is the motor 1
The rotation signal is output according to the change of the magnetic pole of No. 2, and its configuration will be described later with reference to FIG. The magnetic pole sensor 61 outputs three rotation signals HA, HB, and HC, and these rotation signals represent relative steering angles. 2 and 3
As shown in, an absolute steering angle sensor 62 of a potentiometer for detecting the steering angle amounts of the rear wheels 15 and 16 is provided. Thus, the rear wheel steering angle sensor 60 (FIG. 5) is configured by the magnetic pole sensor 61 and the absolute steering angle sensor 62, and the actual steering angle θr of the rear wheels 15 and 16 is detected by this.

As shown in FIG. 3, the rear wheel steering mechanism 18 of this embodiment has a cover 52 fixed to a housing 51, and a motor housing 53 of the motor 12 and a magnetic pole sensor 61 are provided integrally with the cover 52. Has been. FIG.
As is clear from the above, the rack shaft 55 is provided at a right angle to the traveling direction of the vehicle, and both ends of the rack shaft 55 are connected to the knuckle arms of the rear wheels via ball joints 58. A tube 59 is fitted to the right end of the housing 51 in FIG. 4, and even when the rack shafts 55 having different lengths are provided, by replacing the tube 59,
This can be handled without changing the housing 51. A rack 56 is formed on the rack shaft 55, and the rack 56 includes a pinion 57 extending in the front-rear direction of the vehicle.
Is configured to mesh with.

As shown in FIG. 4, a pinion 12p is provided at the tip of a motor shaft 12s of the motor 12, and a gear 12g meshes with the pinion 12p to form a hypoid gear. This hypoid gear is the motor 12
The rotation of the motor shaft 12s is transmitted as the rotation of the gear 12g, but when the rotational force is applied to the gear 12g from the rack shaft 55 side, the reverse efficiency is set to zero so that the motor shaft 12s of the motor 12 does not rotate. Has been done.

The motor 12 is constructed so as to be controlled by a signal from the electronic control unit 20. That is, as shown in FIG. 2, the electronic control unit 20 includes a yaw rate sensor 8, a vehicle speed sensor 9, a front wheel steering angle sensor 17,
Outputs of the rear wheel steering angle sensor 60 including the magnetic pole sensor 61 and the absolute steering angle sensor 62 are supplied, the rotation amount of the motor 12 is set according to these outputs, and a control signal is supplied to the motor 12.

FIG. 5 shows the configuration of the electronic control unit 20. The electronic control unit 20 has a vehicle-mounted battery 41.
Is connected. That is, the battery 41 is connected to the motor driver 44 through the fuse and the power supply terminal IP1, and is connected to the motor driver 44 and the constant voltage regulator 43 through the fuse, the ignition switch 42 and the power supply terminal IP2. The constant voltage regulator 43 outputs a constant voltage Vcc.

The electronic control unit 20 has a microprocessor 45 operated by a constant voltage Vcc, and has the yaw rate sensor 8, vehicle speed sensor 9 and front wheel steering angle sensor 1 described above.
The detection signals of the magnetic pole sensor 61 and the absolute steering angle sensor 62 are also input to the microprocessor 45 via the interface 46. Although not shown, a read-on memory ROM, a random access memory RAM, a motor position counter, etc. are built in. The terminals U, V, W of each phase of the motor 12 are connected to the motor driver 44 of the electronic control unit 20. Electric power is supplied to the motor driver 44 from power supply terminals IP1 and IP2. Then, from the microprocessor 45 to the motor driver 44
A control signal is output to.

As shown in FIGS. 5 and 6, the motor 12 has one end of each winding connected to a motor driver 44 via terminals U, V and W, respectively. In addition, at the end of the motor 12 in the axial direction, a quadrupole disk-shaped magnet 6 shown by a two-dot chain line in FIG.
As shown in FIG. 7, three Hall ICs 65 are arranged at 60 degree intervals on a substrate 64 to which the magnets 3 are fixed and which are arranged on the magnet 63 with a predetermined gap. The outputs of these three Hall ICs 65 are rotation signals HA, HB, HC.
Used as.

That is, when the motor shaft 12s rotates, as shown in FIG.
Hall IC65
The magnet 63 (indicated by N and S pole rings in FIG. 9) rotates relative to (indicated by HA, HB, and HC in FIG. 9),
Rotation signals HA and H which are three outputs of the magnetic pole sensor 61.
B and HC change between a high level (H) and a low level (L) as shown in FIG. FIG. 9 shows a state in which the motor 12 is rotating clockwise (CW). When the motor 12 rotates counterclockwise (CCW), the rotation signals HA, HB, HC of the magnetic pole sensor 61 move in the direction from right to left in the figure.
Are switched. Then, if the winding current of the motor winding 44 is switched in synchronization with the switching of the rotation signals HA, HB, HC, the motor 12 rotates. The motor 1 shown in FIG.
The direction of the winding current during rotation of 2 will be described later.

Further, as shown in FIG. 8, the microprocessor 45 has an interrupt terminal ITR, and normal input terminals (HA, HB, HC) are provided for inputting the rotation signals HA, HB, HC. . The rotation signals HA and HB are input to the exclusive OR circuit EXOR1, and the rotation signal HC and the output signal of the exclusive OR circuit EXOR1 are connected to be input to the exclusive OR circuit EXOR2. Thus, when any one of the rotation signals HA, HB, HC changes, the output of the exclusive OR circuit EXOR2 changes and the interrupt signal is supplied to the interrupt terminal ITR.

As shown in FIG. 5, the terminals U, V, W of each phase of the motor 12 are connected to the motor driver 44 of the electronic control unit 20. As shown in FIG. 6, power is supplied to the motor driver 44 from power supply terminals PIGA and IGA, and a phase switching signal group L1 (L1 is a phase switching signal LA) which is an output signal of the microprocessor 45.
11, LB11, LC11, LA21, LB21, LC
21) and pulse width modulation (Pulse Width)
Modulation) signal PWM1 is input.

The motor driver 44 is constructed as shown in FIG. 6 and is controlled by the phase switching signal group L1 and the pulse width modulation signal PWM1 described above. The phase switching signals LA11, LB11, LC11 for controlling the high side are input to the gate drive circuit G11 via the abnormal current limiting circuit 88. Normally, these input signals are directly output from the output side via the abnormal current limiting circuit 88. The gate drive circuit G11 is a circuit for on / off driving the transistors TA11, TB11, TC11 of the power MOSFET. The gate drive circuit G11 has a boosting function, the boosted voltage is applied to the gates of the transistors TA11, TB11, and TC11, and the boosted voltage is output as the boosted voltage value RV1. Transistor TA1
1, TB11, TC11 are configured so that the high voltage obtained from the power supply terminal PIGA via the pattern fuse PH, the choke coil TC, and the resistor Rs is supplied to the three-phase terminals U, V, W of the motor 12, respectively. It is connected.
The transistors TA11, TB11, TC11, TA
A Zener diode is inserted between the gate and the source of 21, TB21 and TC21, and the power MOSFET
It is used to protect T.

On the other hand, the phase switching signals LA21, LB21, LC21 for controlling the low side are connected to the gate drive circuit G21 via the pulse width modulation signal synthesis circuit 89 and the abnormal current limiting circuit 88. The pulse width modulation signal synthesis circuit 89 includes phase switching signals LA21, LB21, LC.
21 is a circuit for combining 21 with the pulse width modulation signal PWM1. The gate drive circuit G21 is a circuit for driving the transistors TA21, TB21, TC21 of the MOSFET on and off, and these transistors TA21, T21.
B21 and TC21 are three-phase terminals U of the motor 12,
It is arranged so that V and W are connected to the ground of the battery 41. Transistors TA11, TB11, T
Protective diodes D3 to D8 are connected to each of C11, TA21, TB21, and TC21. The voltages supplied to the transistors TA11, TB11, TC11 are simultaneously output as the voltage PIGM1.

A current detection circuit 86 is connected to both ends of the resistor Rs, and the value of the current flowing through the resistor Rs is detected.
The current detection circuit 86 has a current value of 18 A flowing through the resistor Rs.
In the above case, it is determined that the current is an overcurrent, the overcurrent signal is output as the output signal MOC1, the overcurrent signal is given to the pulse width modulation signal synthesizing circuit 89, and the low side is limited. Further, the current detection circuit 86 determines that the current is an abnormal current when the value of the current flowing through the resistor Rs is 25 A or more, and outputs the abnormal current signal as the output signal MS1 and also gives the abnormal current signal to the abnormal current limiting circuit 88 to set the high side. And, it is configured to impose restrictions on the low side. Specifically, all the transistors TA11, T
B11, TC11, TA21, TB21 and TC21 are turned off for a certain period of time after the abnormal current is detected. The current value detected by the current detection circuit 86 is given to the peak hold circuit 101, and the peak hold circuit 101 outputs the peak value of the current value as a peak signal MI1. The peak hold circuit 101 is reset at the timing when the reset signal DR1 switches.

Next, the rotating operation of the motor 12 will be described with reference to FIG. The motor 12 is rotated by setting the pattern of the phase switching signal as shown in Table 1 below according to the states of the rotation signals HA, HB, and HC. The clockwise rotation (CW) is set to right cut, and the counterclockwise rotation (CCW) is set to left cut. First, the order of clockwise rotation 1 in Table 1
The rotation signal is (HA, HB, HC) = (H,
In the case of L, H), the phase switching signal is (LA11, LB1
1, LC11, LA21, LB21, LC21) =
It is output as (H, L, L, L, H, L). This state corresponds to the state in the range of A in FIG. 9, and the rotation signals HA and HC are at the high level (H), as is clear from the relative rotational position relationship of the magnet with respect to the three Hall ICs. The direction of the winding current changes from the U phase to the V phase, and the magnet rotates clockwise in the drawing as the motor 12 rotates. When the magnet rotates about 30 degrees, the rotation signal HA switches from high level to low level. In response to this, the phase switching signal becomes (LA11, LB11, LC11, LA21, LB2
1, LC21) = (L, L, H, L, H, L), the motor 12 further rotates 30 degrees, and the rotation signal HB becomes high level. In this way, the motor 12 is continuously rotated from the state on the left side in FIG. 9 to the state on the right side. Thus, in order to apply the clockwise rotation (CW) or the counterclockwise rotation (CCW) to the motor 12, it is sufficient to switch the pattern of the phase switching signal according to the order of the upper stage or the lower stage of Table 1 below.

[Table 1]

The microprocessor 45 described above is shown in FIG.
The target steering angle calculation unit C0, the motor servo control unit C1, the phase switching control unit C2, the magnetic pole sensor abnormality determination unit C3, the open control unit C4, and the switch SW.
One. In the target steering angle calculation unit C0, the target steering angle θa is set based on the yaw rate γ, the vehicle speed Vs, and the steering angle δ of the front wheels, as will be described later. The control section C1 performs servo control of the motor 12.

That is, in the microprocessor 45, the target steering angle is set according to the control block diagram shown in FIG. 11, and the servo control of the motor 12 is performed. First, in the target value setting unit 21, for example, the front wheels 1
The target steering angle θa of the rear wheels 15 and 16 is set according to the steering angle δ and yaw rate γ of the wheels 3 and 14 and the vehicle speed Vs. Specifically, in the target value setting unit 21, the product of the coefficient K1 set according to the vehicle speed Vs and the output yaw rate γ of the yaw rate sensor 8 and the coefficient K2 set according to the vehicle speed Vs and the front wheel steering angle sensor 17 are set. The product of the output steering angle δ of
1 · γ + K2 · δ), the target steering angle θa is set. For example, when the vehicle is stopped, the rear wheels 15 and 16 are the front wheels 1
The target steering angle θa is set so as to be steered in the opposite direction to the front wheels 13 and 14 in inverse proportion to the steering angles of the steering wheels 3 and 14, thereby reducing the turning radius of the vehicle. When the vehicle is traveling at high speed, the target steering angle θa is set to be proportional to the steering angle of the front wheels 13 and 14, and the rear wheels 15 and 16 are steered in the same direction as the front wheels 13 and 14 to turn the vehicle. The maneuvering stability at the time becomes good.

The target steering angle θa set as described above is
The differentiator 22 differentiates, and the differential gain setting part 23 differentiates the differential value Dθa according to a predetermined characteristic.
θa is obtained. That is, when the absolute value of the differential value Dθa is less than or equal to a predetermined value (for example, 0.12 deg), the differential gain Gθa is set to 0, and when the absolute value of the differential value Dθa is at least a predetermined value (for example, 0.48 deg). Is the differential gain G
θa is set to a predetermined value (for example, 4). Therefore, FIG.
As shown in 6, when the absolute value of the differential value Dθa is within the range of 0.12 to 0.48 deg, the differential gain Gθ is
a has a value of 0 to 4.

On the other hand, the output signals HA, H of the magnetic pole sensor 61
The rotation angle θm of the motor 12 is detected by B and HC,
The actual steering angle θr is output via the steering angle conversion unit 33, and this is supplied to the subtraction unit 24. The output of the magnetic pole sensor 61 is the relative steering angle as described above and does not represent the actual steering angle, but is corrected based on the output of the absolute steering angle sensor 62 in the steering angle conversion unit 33, The actual steering angle θr is output from the steering angle conversion unit 33.

In the subtraction section 24, the actual steering angle θr is subtracted from the target steering angle θa to obtain the steering angle deviation Δθa. This steering angle deviation Δθa is processed through the steering angle deviation dead zone applying unit 25, and as shown in FIG. 17, when the absolute value of the steering angle deviation Δθa is equal to or less than a predetermined value α, the output deviation θ
d is set to 0. Thus, the control is configured to stop when the value of the steering angle deviation Δθa is small. The deviation θd thus obtained is sent to the differentiating section 26 and the proportional section 28. The proportional portion 28 multiplies the deviation θd by a predetermined proportional gain to obtain the proportional term Ps. Further, the deviation θd is differentiated in the differentiator 26, and the steering angle deviation differential value Dθ is obtained.
d is obtained.

Then, the steering angle deviation differential value Dθd is multiplied by the differential gain Gθa set by the differential gain setting unit 23 as described above in the multiplication unit 27 to obtain the differential term Ds. Then, the proportional term Ps and the differential term Ds are added to the adder 29.
And the steering angle control amount, that is, the steering angle value θc is obtained. The steering angle deviation limiter 30 limits the steering angle value θc to set the control amount Oc in proportion to the steering angle value θc as shown in FIG. 18, and the control amount Oc is set to a predetermined value. It is set so as not to be higher than the upper limit value (for example, 1.5 deg) or lower than a predetermined lower limit value (for example, -1.5 deg).

The control amount Oc thus obtained is converted into a duty Dy by the deviation-duty converter 31 and supplied to the pulse width modulation (PWM) unit 32. In the pulse width modulator 32, a pulse signal Pw corresponding to the duty Dy is formed and output to the motor driver 44. The motor driver 44 servo-controls and rotationally drives the motor 12 according to the pulse signal Pw supplied thereto. An integral term may be added to the PD control.

In the phase switching control section C2 shown in FIG. 10, according to the rotation signals HA, HB, HC and the output of the exclusive OR circuit EXOR2, FIGS.
Processing is performed as shown in the flowchart of FIG. Further, in the magnetic pole sensor abnormality determination unit C3, the rotation signal HA,
Based on the outputs of HB, HC and the exclusive OR circuit EXOR2, the abnormality of the magnetic pole sensor 61 is determined,
When it is determined that there is an abnormality, the switch SW1 is configured to switch to the open control unit C4 side. The open control section C4 is controlled so that the absolute value of the actual steering angle θr of the rear wheels becomes zero according to an open control routine (not shown). That is, when the magnetic pole sensor 61 is determined to be abnormal, the phase switching signal pattern is controlled so that the rear wheels 15 and 16 return to the neutral position.

In the microprocessor 45, the drive control of the motor 12 is performed according to the flow charts shown in FIGS. FIG. 12 shows a main routine. After initialization is performed in step 101, the drive control of the motor 12 is performed at a predetermined time interval, for example, a control cycle of 5 ms (step 1).
02 or later). First, in step 103, the target steering angle θ
After the above-mentioned various controlled variables such as a are calculated, step 10
4, the motor servo control is performed. Here, as described with reference to FIG. 11 described above, basically, the target steering angle θa
The steering angle value θc is obtained based on the steering angle deviation Δθa of the actual steering angle θr, and the control amount Oc is set based on the steering angle value θc as described above. Then proceed to step 105
The phase switching condition including the rotation direction of the motor 12 is set according to the change of the steering angle value θc.

FIG. 13 shows a subroutine for setting the phase switching condition performed in step 105. The present steering angle value θc (n) and the previous steering angle value θc (n-1) are positive, negative or zero. Which state is determined. First, in step 201, it is judged whether or not the steering angle value θc (n) of this time is zero (that is, there is no steering angle deviation). If it is zero, the drive control of the motor 12 is unnecessary, so in step 202. A phase switching control stop command is output and the process returns to the main routine.

If the current steering angle value θc (n) is not zero, it is further determined in step 203 whether or not the previous steering angle value θc (n-1) is zero. Since the steering angle deviation has occurred this time, the start flag SF for starting the phase switching control is set (1) in step 204. Then, in step 205, whether the present steering angle value θc (n) is positive or negative is determined, and if positive, the process proceeds to step 206, and the left rotation flag LF for rotating leftward is set, and if negative, the step is performed. Proceeding to 207, the right rotation flag RF for rotating in the right direction is set.

In step 203, the previous steering angle value θc
If it is determined that (n-1) is not zero, step 20
The process proceeds to step 8 to determine whether the steering angle value θc (n) this time is positive or negative. If negative, the process proceeds to step 209, and the previous steering angle value θc (n-
The sign of 1) is judged. Here, the previous steering angle value θc (n-1)
Is determined to be positive, the steering angle value θc has changed from positive to negative, so the right rotation flag RF is set and the start flag SF is set. Step 20
When the previous steering angle value θc (n-1) is determined to be negative in 9, the steering angle value θc is a change from negative to negative, and therefore step 211
The process proceeds to step S6 and the right rotation flag RF remains set.

When the current steering angle value θc (n) is determined to be positive in step 208, it is further determined in step 212 whether the previous steering angle value θc (n-1) is positive or negative. Since the steering angle value θc has changed from negative to positive, the routine proceeds to step 213, where the left rotation flag LF is set and the start flag SF is set. Previous steering angle value θ
When c (n-1) is positive, the change from positive to positive, so that the left rotation flag LF remains set in step 214. Either the flag LF or RF indicating the rotation direction set as described above and the start flag S
Depending on the state of F, the phase switching control is performed in the main routine of FIG. 12 or it is stopped in accordance with the stop command in step 202.

Returning to FIG. 12, the presence or absence of a stop command is determined in step 106. When there is a stop command in step 202, the phase switching control is stopped in step 107, and the drive control of the motor 12 is not performed. If there is no stop command, the routine proceeds to step 108, where the state of the start flag SF is judged. Here, if it is determined that the start flag SF is set (1), the routine proceeds to step 109, where it is determined whether or not the right rotation flag RF is set, and if it is set, it is rotated right at step 110. Phase switching control is performed, otherwise step 111
After the counterclockwise rotation phase switching control is performed, the process returns to step 102. Start flag SF in step 108
When it is determined that is not set (0), the process returns to step 102 without performing the phase switching control,
The above process is repeated.

The motor 12 is started as described above,
When any of the rotation signals HA, HB, HC is output and the interrupt signal is input to the interrupt terminal ITR shown in FIG.
The interrupt routine shown in is executed. When the interrupt process is started, the motor position counter is counted up or down in step 301. That is, every time an interrupt signal is input, for example, a rightward rotation is counted up (+1) and a leftward rotation is counted down (−1) according to the rotation direction of the motor 12, The rotational position of the motor 12 is detected based on the count value.

Then, in step 302, the start flag SF is reset (0). As a result, FIG.
The phase switching control is performed in step 304 or 305 of the interrupt routine of FIG. 14 without performing the phase switching control in step 110 or 111 of the main routine.
That is, when it is determined in step 303 that the right rotation flag RF is set (1), in step 304, the right rotation phase switching control is performed according to the phase switching signal pattern based on the count value of the motor position counter. If it is determined that the right rotation flag RF is not set (the left rotation flag LF is set), step 30
At 5, counterclockwise phase switching control is performed. in this way,
When the phase switching control is being performed in step 304 or 305 in the interrupt routine, the start flag S
Since F is in a reset state and the phase switching control in step 110 or 111 of the main routine is not performed, the phase switching control does not interfere between the two routines and the rotation signals HA, HB, HC are output. Timing is 5m
Even if it is earlier than the control cycle of s, the phase switching control can be reliably performed.

As described above, not only the rotation signals HA, HB, and HC, but also the rotation signals HA, HB, and HC are supplied to the magnetic pole sensor abnormality determination section C3 of FIG.
The output of the exclusive OR circuit EXOR2 of FIG. 8 is also configured to be used for abnormality determination. Thus, even when an abnormality occurs in the circuit including the exclusive OR circuits EXOR1 and EXOR2, the open control can be surely switched. In particular, in the present embodiment, the interrupt routine is started by the output of the exclusive OR circuit EXOR2, and the phase switching control is performed instead of the main routine. Therefore, the exclusive OR circuit EXOR1, If an abnormality occurs in the circuit including the EXOR2 and the interrupt signal is not input to the interrupt terminal ITR, the interrupt routine does not start, and it is impossible to determine the abnormality on the interrupt side. Therefore, the above-mentioned configuration and the monitoring in the main routine can surely detect the abnormality of the circuit.

Further, as described above, the phase switching control is performed by the interrupt processing, and the random access memory is used as a memory involved in the interrupt routine. However, if there is only one memory, in the event of a failure, It is not preferable because it causes a malfunction. Therefore, as another embodiment of the present invention, as shown in FIG. 15 as an example of interrupt processing, two random access memories RAM1 and RA for instructing the rotation direction of the motor 12 in the electronic control unit 20.
It is desirable to provide M2 (not shown) and use one for right rotation and the other for left rotation, or to provide a pair of the same contents.

FIG. 15 shows a rotation signal edge interrupt routine according to an embodiment provided with two random access memories. In step 401, the motor position counter is counted up or down as in step 301 of FIG. After that, in step 402, two random access memories RAM1,
RAM2 is checked. If the random access memory on the commanded side is normal in step 403, the process proceeds to step 404 and the phase switching control is performed as described above, but if it is determined to be abnormal, the process proceeds to step 405 and the phase switching control is stopped. To be done.

[0044]

Since the present invention is constructed as described above, it has the following effects. That is, the brushless motor drive device according to the first aspect includes an interrupt control means,
Since the interrupt processing is performed according to the rotation signal to stop the output of the phase switching signal by the phase switching control means and the phase switching signal is output to the exciting means, for example, the phase switching control means Even if the rotation signal changes earlier than a predetermined time interval for outputting the phase switching signal, the interrupt control means can reliably output the phase switching signal, and smooth phase switching control can be performed. .

Further, the brushless motor drive device according to the second aspect of the present invention comprises the abnormality determining means and is configured to perform the abnormality determination based on the rotation signal and the interrupt signal. It is possible to reliably make an abnormality determination including the portion reaching the control means.

[Brief description of drawings]

FIG. 1 is a block diagram showing an outline of a configuration of a drive device for a brushless motor according to the present invention.

FIG. 2 is an overall configuration diagram of a vehicle rear wheel steering device to which a brushless motor drive device according to an embodiment of the present invention is applied.

FIG. 3 is a front view of a rear wheel steering mechanism according to an embodiment of the present invention.

FIG. 4 is a partial cross-sectional view of a rear wheel steering mechanism according to an embodiment of the present invention.

FIG. 5 is a circuit configuration diagram of an electronic control unit used in an embodiment of the present invention.

FIG. 6 is a circuit diagram of a motor driver according to an embodiment of the present invention.

FIG. 7 is a front view of a substrate portion of the magnetic pole sensor according to the embodiment of the present invention.

FIG. 8 is a circuit diagram provided for interrupt processing in an embodiment of the present invention.

FIG. 9 is an operation explanatory diagram of the brushless motor according to the embodiment of the present invention.

FIG. 10 is a functional block diagram of a microprocessor according to an embodiment of the present invention.

FIG. 11 is a control block diagram relating to motor servo control in one embodiment of the present invention.

FIG. 12 is a flowchart showing a main routine of drive control of a brushless motor according to an embodiment of the present invention.

FIG. 13 is a flowchart showing a subroutine for setting phase switching conditions in drive control of a brushless motor according to an embodiment of the present invention.

FIG. 14 is a flowchart showing an interrupt routine of a rotation signal edge interrupt in the drive control of the brushless motor according to the embodiment of the present invention.

FIG. 15 is a flowchart showing an interrupt routine of a rotation signal edge interrupt in drive control of a brushless motor according to another embodiment of the present invention.

FIG. 16 is a graph showing the input / output characteristics of the differential gain setting section in the embodiment of the present invention.

FIG. 17 is a graph showing the input / output characteristics of the steering angle deviation dead zone applying section in the embodiment of the present invention.

FIG. 18 is a graph showing the input / output characteristics of the steering angle-deviation limiter in one embodiment of the present invention.

[Explanation of symbols]

 8 Yaw Rate Sensor 9 Vehicle Speed Sensor 10 Front Wheel Steering Mechanism 11 Rear Wheel Steering Angle Sensor 12 Motors 13, 14 Front Wheels 15, 16 Rear Wheel 17 Front Wheel Steering Angle Sensor 18 Rear Wheel Steering Mechanism 20 Electronic Control Unit 22 Differential Unit, 23 Differential Gain Setting Unit 24 subtraction unit 25 steering angle deviation dead zone imparting unit 26 differentiation unit, 27 multiplication unit 28 proportional unit, 29 addition unit 30 steering angle deviation limiter 31 deviation-duty conversion unit 32 pulse width modulation unit, 33 steering angle conversion unit 41 battery 43 constant Voltage regulator 44 Motor driver 45 Microprocessor 46 Interface 60 Rear wheel steering angle sensor 61 Magnetic pole sensor 62 Absolute steering angle sensor 63 Magnet 64 Board 65 Hall IC

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsuhiko Sato 2-1-1 Asahi-cho, Kariya city, Aichi Aisin Seiki Co., Ltd.

Claims (2)

[Claims] 1. A brushless motor having an exciting coil of at least three phases and having a motor shaft that rotates according to the excitation state of the exciting coil, and a rotation that outputs a rotation signal according to the rotational position of the motor shaft. A sensor, a phase switching control means for switching a phase switching signal pattern for the exciting coil in response to a change in the rotation signal at predetermined time intervals, and outputting a phase switching signal, and the excitation in response to the phase switching signal. In a brushless motor driving device including an exciting means for supplying a current to a coil, an interrupt process is performed according to the rotation signal to stop the output of the phase switching signal by the phase switching control means, and the excitation A brushless motor drive device comprising an interrupt control means for outputting the phase switching signal to the means. 2. The brushless motor drive device according to claim 1, further comprising an abnormality determination unit that determines an abnormality based on a rotation signal of the rotation sensor and an interrupt signal of the interrupt control unit.