JP2003224992A - Drive method for brushless dc motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simplify handling and to switch energizing states with proper timing. <P>SOLUTION: At a time t8 elapsing from a time t7 by a first timer value α, an excitation switching operation is performed, based on the starting edge of a COMM signal detected at the time t7. In order to keep energized state, after the switching over a period of an edge interval time (cycle) T of the COMM signal, a second timer value T equal to the cycle T is set to a subtraction timer. At a time t10 elapsing from the time t8 by the second timer value T, a second excitation switching operation is performed. In order to prevent edge-detection interrupting handling from being conducted caused by spike noise generated in the second switching, a third timer value β is set to the subtraction timer as a period, during which the COMM signal is inhibited to be inputted. At a time t11 elapsing form the time t10 by the third timer value β, the COMM signal is allowed to be inputted, thus stopping the operation of the subtraction timer. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of driving a brushless DC motor which uses a permanent magnet for a field, and more particularly, to detect the magnetic pole position of a rotor having a permanent magnet based on the terminal voltage of the motor. Sensorless drive technology.

[0002]

2. Description of the Related Art Conventionally, as a controller for a brushless DC motor that uses a permanent magnet for a field, for example, energization control for a three-phase stator winding is performed according to the magnetic pole position of a rotor having a permanent magnet. Therefore, as a position sensor for detecting the magnetic pole position of the rotor, for example, there is known a control device including a Hall element or the like provided for each phase and switching the energized state based on a detection signal from each position sensor. However, in such a control device, an error occurs in the mechanical positional relationship due to, for example, variations in the mounting position when mounting a position sensor such as a Hall element on the motor,
When the signal of the position sensor indicating the predetermined reference position shows a value deviated from the true reference position, the timing of phase output for switching the energization state to the motor may be deviated. Moreover, the provision of the position sensor causes a problem that the number of parts of the motor increases and the apparatus configuration becomes complicated. For such problems, conventionally,
For example, as in the brushless DC motor disclosed in JP-A-61-112591, the magnetic pole position of the rotor is detected based on the terminal voltage at each input / output terminal of the three-phase stator winding, and the motor is energized. A sensorless driving method for switching the state is known.

[0003]

However, in the brushless DC motor according to the above-mentioned conventional technique, the terminal voltage at each input / output terminal of the three-phase stator winding is subjected to waveform shaping by a band pass filter or the like, for example. Although the waveform is created, if, for example, the load of the motor fluctuates, the phase delay waveform is distorted, which may cause an error in the timing for switching the energization state.

The present invention has been made in view of the above circumstances, and switches the energization state at an appropriate timing while preventing the processing from becoming complicated, for example, even when the load of the motor changes. It is an object of the present invention to provide a method of driving a brushless DC motor capable of performing the same.

[0005]

In order to solve the above problems and achieve the above object, a method of driving a brushless DC motor according to the present invention is a rotor having a permanent magnet, and this rotation. A plurality of phase stator windings (for example, armature coils 22U, 22V, 22W in the embodiments described later) that generate a rotating magnetic field for rotating the child, and one end of each of the plurality of phase stator windings. A brushless DC motor having a plurality of parts connected in common is provided with a plurality of switching elements, and by energization switching means (for example, a motor driving section 12 in an embodiment to be described later) that sequentially commutates the energization of the stator winding. A method of driving a brushless DC motor that is rotationally driven, wherein a terminal voltage of the stator winding (for example, a combined voltage in an embodiment described later) is a predetermined threshold value (for example, described later). When it is E / 2) or more at facilities of the embodiment, the first step to start the counting of the first timer value (e.g., step S in the embodiment described below
29), and when the counting of the first timer value is completed, the energization switching means diverts the current to the stator winding to start counting the second timer value (for example, Step S4 in the embodiment described later
3 and step S44), and a third step (for example, a step in an embodiment described later) in which the energization switching unit commutates the energization of the stator winding when the counting of the second timer value is completed. S46) is included.

According to the brushless DC motor driving method as described above, in a brushless DC motor in which one ends of stator windings of a plurality of phases are commonly connected, the energization switching means energizes the stator windings. When commutating sequentially,
For each energization switching operation, for example, the terminal voltage of the stator winding corresponding to the non-energized phase or the like becomes a predetermined threshold value or more at a predetermined timing. Since the predetermined timing is a timing at which the magnetic pole position of the rotor becomes a predetermined reference position, the current is switched to the stator winding by the energization switching means with this predetermined timing as a reference, thereby rotating the rotor. Appropriate drive control can be performed according to the magnetic pole position of the child. Here, in the first step, counting of the first timer value is started with reference to the timing when the terminal voltage of the stator winding becomes equal to or higher than a predetermined threshold value. Then, in the second step, the first
When the counting of the timer value is completed, the first energization switching is performed and the counting of the second timer value is started. And
In the third step, the second energization switching is performed when the counting of the second timer value is completed. As a result, the energization switching can be executed twice with reference to the timing when the terminal voltage of the stator winding becomes equal to or higher than the predetermined threshold value, and the processing from the first step to the third step described above is repeated. The appropriate drive control according to the magnetic pole position of the rotor can be continued, and the brushless DC motor can be stably driven.

Further, in the method for driving the brushless DC motor according to the present invention as defined in claim 2, when the counting of the second timer value is completed, the execution of the first step is restricted and the third timer value A fourth step of starting the counting (for example, step S26 and step S47 in the embodiment described later) and a fifth step of releasing the restriction on the execution of the first step when the counting of the third timer value is completed. It is characterized by including a step (for example, step S48 in the embodiment described later).

According to the above method of driving the brushless DC motor, by restricting the execution of the first step over the period in which the counting of the third timer value is executed,
It is possible to reliably prevent the counting of the first timer value from being started due to spike noise generated by the counter electromotive voltage at the time of switching the energization, and it is possible to appropriately drive the brushless DC motor.

Further, the driving method of the brushless DC motor of the present invention according to claim 3 includes a sixth step of changing the first timer value (for example, step S29 in the embodiment described later also serves). Is characterized by.

According to the method of driving the brushless DC motor as described above, the advance angle control can be performed by changing the first timer value. For example, by changing the first timer value to a relatively small value, Based on the timing when the terminal voltage of the stator winding becomes equal to or higher than a predetermined threshold,
The timing of executing the first energization switching and the timing of executing the second energization switching can be advanced.

The brushless DC motor controller according to the present invention includes a rotor having permanent magnets and a plurality of phases of stator windings for generating a rotating magnetic field for rotating the rotor (for example, an embodiment described later). Brushless DC in which each armature coil 22U, 22V, 22W) in the above-mentioned form is connected, and each one end of the stator windings of the plurality of phases is commonly connected.
The motor includes a plurality of switching elements, and energization switching means for sequentially commutating the energization of the stator winding (for example,
A controller for a brushless DC motor that is rotationally driven by a motor drive unit 12) in an embodiment described below, in which a terminal voltage of the stator winding (for example, a combined voltage in the embodiment described below) is a predetermined threshold value (for example, A position reference signal output means (for example, a COMM signal according to an embodiment described later) that outputs a position reference signal related to the magnetic pole position of the rotor when it is equal to or more than E / 2) in the embodiment described later (for example, a COMM signal in the embodiment described later). The first reference means (for example, the position reference signal generation unit 13 in the embodiment described later) and the first reference means for starting the counting of the first timer value when the position reference signal is output by the position reference signal output means (for example, Step S29) in the embodiment described later, and the first
When the counting by the counting means is completed, the energization switching means diverts the energization to the stator winding,
First switching control means (for example, step S43 and step S44 in the embodiment described later) that starts counting the second timer value, and the energization switching means when the counting by the first switching control means is completed. Second switching control means (for example, step S46 in the embodiment described later) for commutating the energization to the stator winding is provided.

According to the brushless DC motor control device having the above-mentioned configuration, the appropriate drive control can be continued based on the position reference signal relating to the magnetic pole position of the rotor, and the brushless DC motor can be stably driven. it can.

Further, the controller for the brushless DC motor according to the present invention controls the operation of the first counting means and counts the third timer value when the counting by the second switching control means is completed. Restricting means to start (for example, step S26 and step S47 in the embodiment described later), and restriction releasing means to release restriction on the operation of the first counting means when the counting by the restricting means is completed (for example, And step S48) in the embodiment described later.

According to the controller of the brushless DC motor having the above-mentioned configuration, the operation of the first counting means is restricted over the period in which the counting of the third timer value is executed, so that the counter electromotive voltage at the time of switching the energization is used. It is possible to reliably prevent the counting of the first timer value from being started due to the generated spike noise, and it is possible to appropriately drive the brushless DC motor.

Further, the brushless DC motor control device according to the present invention is characterized by including timer value changing means for changing the first timer value (for example, step S29 in the embodiment described later also serves). .

According to the controller of the brushless DC motor having the above structure, the advance angle control can be performed by changing the first timer value. For example, by changing the first timer value to a relatively small value, it is fixed. The timing at which the first energization switching is performed and the timing at which the second energization switching is performed can be advanced with reference to the timing when the terminal voltage of the subsidiary winding becomes equal to or higher than the predetermined threshold value.

Further, in the brushless DC motor control device according to the present invention, the position reference signal output from the position reference signal output means is output a predetermined number of times (for example, the reading counter C in the embodiment described later).
R) is included in the output number detecting unit (for example, step S24 in the embodiment described later), and the first counting unit detects the output number detected by the output number detecting unit is a predetermined number (for example, described later). It is characterized in that the counting of the first timer value is prohibited when the number of readings is less than the reading number NR).

According to the brushless DC motor controller having the above-mentioned structure, for example, even when the energization switching means performs chopping control for a plurality of switching elements,
The first counting means can reliably distinguish the spike noise generated by the counter electromotive voltage at the time of switching the energization from the position reference signal, and the counting of the first timer value is started due to the spike noise. This can be reliably prevented, and the brushless DC motor can be appropriately driven.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a method for starting a brushless DC motor according to the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a brushless DC realizing a method for starting a brushless DC motor according to an embodiment of the present invention.
FIG. 3 is a configuration diagram of the motor control device 10, FIG. 2 is a timing chart showing the operation of the switching element in each control stage, and FIGS. 3A to 3F are motors 11 in each control stage shown in FIG. 2. FIG. 6 is a schematic diagram showing the operation of FIG.

A controller 10 for a brushless DC motor according to this embodiment has a motor 1 as shown in FIG.
1, a motor drive unit 12, and a position reference signal generation unit 13
And an ECU (electronic control unit) 14.

The motor 11 is, for example, a brushless DC motor using a permanent magnet for the field, and the rotor 21 having one magnetic pole pair of N pole and S pole has field magnetic flux of three phases (U phase and V phase).・ W-phase) armature coils 22U, 22V, 22
It is linked to W.

The motor drive unit 12 forms a PWM inverter by pulse width modulation (PWM), for example, and includes a plurality of high side switching elements SUH, SVH, S.
WH and low side switching elements SUL, SVL, S
A plurality of switching elements SUH, SV each having a bridge circuit configured by bridge connection using WL are configured.
H, SWH, SUL, SVL, SWL are, for example, MOS
FET (Metal Oxide Semi-conductor Field Effect Tr
ansistor).

High-side switching elements SUH, SV
The drains of H and SWH are all connected to the DC input / output terminal 12D, and the low-side switching elements SUL, SVL,
The sources of SWL are all connected to the ground terminal 12G. The source of the U-phase high-side switching element SUH is connected to the drain of the U-phase low-side switching element SUL,
The source of the V-phase high-side switching element SVH is connected to the drain of the V-phase low-side switching element SVL, and the source of the W-phase high-side switching element SWH is connected to the drain of the W-phase low-side switching element SWL. The U-phase AC input / output 12U is connected to the source of the U-phase high-side switching element SUH and the drain of the U-phase low-side switching element SUL, and is connected to the V-phase AC input / output terminal 12
V is connected to the source of the V-phase high-side switching element SVH and the drain of the V-phase low-side switching element SVL, and the W-phase input / output terminal 12W is the source of the W-phase high-side switching element SWH and the W-phase low-side switching element. It is connected to the drain of SWL. Further, each switching element SUH, SVH, SWH, SUL, SVL,
The gate of SWL is connected to the ECU 14 described later.

When the motor 11 operates as an electric motor, the motor drive unit 12 converts a direct current input from the direct current power source E through the direct current input / output terminal 12D and the ground terminal 12G into an alternating current, and this alternating current Is output from the AC input / output terminals 12U, 12V, 12W and is sent to the armature coils 22U, 22V, 22W of the motor 11. That is, the motor drive unit 12 switches the current paths from the DC power source E to the armature coils 22U, 22V, 22W of the motor 11 by switching the energization states of the high-side switching elements SUH, SVH, SWH. The current paths from the armature coils 22U, 22V, 22W of the motor 11 to the DC power supply E are switched by switching the energization states of the low-side switching elements SUL, SVL, SWL.

The position reference signal generator 13 is provided with terminal voltages U of the armature coils 22U, 22V, 22W of the motor 11.
When the combined voltage obtained by combining OUT, VOUT, and WOUT exceeds a predetermined threshold, a COMM signal of a logic “high” level (ON) is output, and when the combined voltage is equal to or lower than the predetermined threshold, the logic “ It includes a comparator 31 that outputs a "low" level (OFF) COMM signal. That is, a predetermined ratio (for example, 1
The voltage (for example, E / 2) at the voltage dividing point of the DC power supply E divided into / 2) is input to the inverting input of the comparator 31, and the combined voltage of the armature coils 22U, 22V, 22W is the comparator. It is input to the non-inverting input of 31.

The ECU 14 controls the switching elements SUH, SVH, SWH, SUL, SV of the motor drive unit 12.
The switching elements SUH and SV are connected to the gates of L and SWL by pulse width modulation (PWM), for example.
Each pulse UH, VH, WH, UL, VL for turning on / off H, SWH, SUL, SVL, SWL
Output WL. Here, the ECU 14 determines that each pulse U
Duty ratio DU of H, VH, WH, UL, VL, WL
TY, that is, a map (data) of the on / off ratio is stored according to the state of the motor 11, and each pulse UH, VH, WH, UL, V based on the value obtained by the map search.
Outputs L and WL. The ECU 14 controls the high-side switching elements SUH, SVH, SWH when the high-side switching elements SUH, SVH, SWH are switched over.
Chopping control is performed by repeating on / off driving a plurality of times within a predetermined cycle in which H, SVH, and SWH are in the energized state. For example, each low-side switching element SUL, SV
When the energization states of L and SWL are switched and controlled, a single ON drive is maintained for a predetermined period of energization.

Further, the ECU 14 stores a map (data) of a switching cycle according to the state of the motor 11 when the energization state of each switching element SUH, SVH, SWH, SUL, SVL, SWL is controlled to be switched. The pulses UH, VH, WH, UL, VL, and WL are switched on / off and output in accordance with the switching cycle based on the value obtained by the map search. As a result, the ECU 14 performs start control of the motor 11 and drive control according to the COMM signal, as will be described later.

For this reason, the ECU 14 informs the ECU 14 of the state of the motor 11, for example, the detection signal from the torque detector 41 for detecting the motor torque Tor.
The detection signal from the motor temperature detector 42 for detecting the temperature Tmag of 1 and the phase voltage of the motor 11, for example, the U phase AC input / output 12U of the AC input / output terminals 12U, 12V, 12W of the motor drive unit 12. Between the neutral point and the neutral point 22N
Phase voltage Vun and V phase AC input / output 12V and neutral point 22
Each phase voltage detector 4 for detecting the V phase voltage Vvn between N and
The detection signals from 4U and 44V and the detection signals from the phase current detectors 45U and 45V that detect the phase currents supplied to the phases of the motor 11, for example, the U-phase current Iu and the V-phase current Iv, are input. ing.

Here, when the ECU 11 rotationally drives the motor 11, for example, FIGS. 2 and 3 (a)-(f) are used.
, Each of the six control stages ST1, ..., ST
6 is sequentially switched and set. That is, in the first control stage ST1, only the U-phase high-side switching element SUH and the V-phase low-side switching element SVL are energized, and the U-phase AC input / output 12U, the U-phase armature coil 22U, and the V-phase are sequentially arranged. A current flows through the armature coil 22V and the V-phase AC input / output 12V. Then, in the second control stage ST2, the U-phase high-side switching element SUH
And only the W-phase low-side switching element SWL is turned on, and the U-phase AC input / output 12U, the U-phase armature coil 22U, the W-phase armature coil 22W, and the W-phase AC input / output 12 are sequentially arranged.
An electric current flows through W.

Then, in the third control stage ST3, only the V-phase high-side switching element SVH and the W-phase low-side switching element SWL are energized, and V
A current flows through the phase AC input / output 12V, the V phase armature coil 22V, the W phase armature coil 22W, and the W phase AC input / output 12W. Then, in the fourth control stage ST4, only the V-phase high-side switching element SVH and the U-phase low-side switching element SUL are energized, and the V-phase AC input / output 12V, the V-phase armature coil 22V, and the U-phase are sequentially arranged. A current flows through the armature coil 22U and the U-phase AC input / output 12U.

Then, in the fifth control stage ST5, only the W-phase high-side switching element SWH and the U-phase low-side switching element SUL are energized, and W sequentially.
Current flows through the phase AC input / output 12W, the W phase armature coil 22W, the U phase armature coil 22U, and the U phase AC input / output 12U. Then, in the sixth control stage ST6, only the W-phase high-side switching element SWH and the V-phase low-side switching element SVL are energized, and the W-phase AC input / output 12W, the W-phase armature coil 22W, and the V-phase are sequentially arranged. A current flows through the armature coil 22V and the V-phase AC input / output 12V.

That is, the ECU 14 controls the pulses UH, VH, W in the control stages ST1, ..., ST6.
Rotating the rotor 21 of the motor 11 in a predetermined direction (for example, a clockwise direction shown in FIGS. 3A to 3F) by switching and outputting ON / OFF patterns for H, UL, VL, and WL. Drive it. Along with this, the position reference signal generator 13 causes the control stages ST1, ..., ST6.
Non-energized phase armature coils 22U, 22V, 22W
When each of the terminal voltages UOUT, VOUT, and WOUT exceeds a predetermined threshold value (for example, E / 2), the COMM signal of the logic “high” level is output. That is, for example, CO
At the time when the MM signal changes from the logical “low” level to the “high” level (the rising edge of the COMM signal), the magnetic pole position of the rotor 21 of the motor 11 becomes equal to the predetermined reference position. In addition, the position reference signal generation unit 13 uses the switching elements SUH, SVH, SWH, SUL, and S.
Even at the time of switching the conduction state of VL and SWL (for example, the times S1, S3 and S5 for the low side switching elements SUL, SVL and SWL shown in FIG. 2), the logic " High level CO
An MM signal (hereinafter referred to as spike noise) is output.

The ECU 14 controls the motor 1 as described later.
, ST6 is selected as the startup control stage, and each pulse UH, VH, WH, U corresponding to the startup control stage is selected.
An on / off pattern for L, VL, and WL is output for a predetermined time, for example, to perform initial excitation. And
Until the rotation speed N of the motor 11 reaches the predetermined rotation speed #N, the motor 11 is forcibly rotated by a predetermined excitation switching operation, for example, a process of sequentially switching and setting the six control stages ST1, ..., ST6. Drive it. At this time,
As will be described later, the ECU 14 controls the pulse width modulation (PW
Each switching element SUH, SVH, SW by M)
The duty ratio DUTY of each pulse UH, VH, WH, UL, VL, WL for driving on / off of H, SUL, SVL, SWL is gradually changed, for example, is increased, and, for example, each of the six controls is controlled. Stage ST1,
The switching cycle of the excitation switching operation (that is, the starting rotation speed of the motor 11) that sequentially sets and switches ST6 is changed according to the state of the motor 11.

Further, the ECU 14 is, as described later,
When the rotation speed N of the motor 11 becomes equal to or higher than the predetermined rotation speed #N, the compulsory excitation switching operation at the time of startup is finished,
Excitation switching operation according to the COMM signal related to the magnetic pole position of the rotor 21 of the motor 11, for example, each of the six control stages S
The motor 11 is driven to rotate by a process of sequentially switching and setting T1, ..., ST6 according to the magnetic pole position of the rotor 21. At this time, the ECU 14 will
When the COMM signal is at the logic "high" level due to the spike voltage, the COMM signal (that is, spike noise) is set to be ignored.

The brushless DC motor control device 10 according to the present embodiment has the above-described structure. Next, the operation of the brushless DC motor control device 10 will be described. FIG. 4 is a flowchart showing the operation of the brushless DC motor control device 10 shown in FIG. 1, particularly the startup process, and FIG. 5 shows the operation of the brushless DC motor control device 10 shown in FIG. 1, especially the edge detection interrupt process. 6 and 7 are flowcharts showing the brushless D shown in FIG.
9 is a flowchart showing an operation of the C motor control device 10, particularly a timer interrupt process, FIG. 8 is a diagram showing an example of a timing chart showing an execution timing of each process shown in FIGS. 4 to 7, and FIG. It is a principal part enlarged view of the timing chart shown in FIG.

The starting process executed when the motor 11 is started will be described below. First, step S shown in FIG.
In 01, it is determined whether the flag value of the activation flag F_ST is set to "1". If the result of this determination is "YES", then a series of processing is terminated. On the other hand, if the result of this determination is "NO", then step S0
Go to 2. Next, in step S02, the motor 1
It is determined whether or not it is in a stopped state in which the rotation speed N of 1 becomes zero. When this determination result is “NO”, that is, the motor 1
If 1 is in the rotating state, the series of processes is ended. on the other hand,
If the result of this determination is "YES", then step S03.
Then, it is determined whether the target DUTY of the motor output calculated based on various control parameters is zero.

The determination result in step S03 is "YES".
In the case of, the process proceeds to step S04, and each control stage S
Any one of T1, ..., ST6 is selected, and each pulse UH, VH, WH, UL, VL, according to the selected control stage.
Execution of the process of switching the ON / OFF pattern for the WL and outputting is prohibited, and the series of processes is ended. On the other hand, when the determination result in step S03 is "NO", the process proceeds to step S05, the counter value of the read counter CR is set to zero, and the process proceeds to step S06.

In step S06, a predetermined DUTY of the motor output preset for the control at the time of starting the motor 11 is set as the starting DUTY, and any one of the control stages ST1, ..., ST6 is set at the starting control stage. To choose as. Then, in step S07, a predetermined starting timer value S is set in the timer, and each pulse UH, VH, WH, U corresponding to the starting control stage is set.
The on / off patterns for L, VL, and WL are output to perform initial excitation, and the start D set in step S06
The motor 11 is forcibly rotationally driven according to the UTY. Then, in step S08, "1" is set to the flag value of the activation flag F_ST, and the series of processes is ended.

The edge detection interrupt processing will be described below. It should be noted that this edge detection interrupt processing is, for example, COM.
This is processing that is repeatedly executed for each rising edge of the M signal. First, in step S21 shown in FIG. 5, it is determined whether or not the DUTY of the motor output is greater than or equal to a predetermined value #DUTY (for example, # DUTY = 95%). If the result of this determination is "YES", the flow proceeds to step S22, the reading count NR is set to a predetermined first count # NR1 (for example, # NR1 = 1), and the flow proceeds to step S24.
On the other hand, if the result of this determination is “NO”, then step S
23, a predetermined second number # NR2 is added to the read number NR.
(For example, # NR2 = 3) is set, and the process proceeds to step S24. The read number NR is, for example, a COMM signal in which the COMM signal changes from a logic “low” level to a “high” level.
It is a predetermined determination threshold for the read counter CR, which is the number of times the rising edge of the signal is detected.

In step S24, the read counter CR is counted, and the process proceeds to step S25. In step S25, it is determined whether or not the read counter CR is equal to the predetermined read number NR. If this determination result is "NO",
That is, when the read counter CR is less than the predetermined read number NR, the series of processes is ended. On the other hand, if the result of this determination is "YES", then the operation proceeds to step S26. As a result, for example, in the processing in the position reference signal generation unit 13 or the like, the DUTY of the motor output becomes equal to or greater than the predetermined value #DUTY, so that the COMM signal originally composed of a plurality of ON / OFF repetitions becomes a single ON signal. Even if it is output as a signal consisting of only, it is possible to determine that the rising edge of the COMM signal has been detected without determining that it is mere spike noise.

In step S26, the edge detection interrupt process is prohibited and the process proceeds to step S27. Step S
27, the edge interval time (cycle) T, that is, C
A period during which a series of ON / OFF repetitions in the OMM signal is continued, that is, each control stage ST1, ..., ST
6 non-energized phase armature coils 22U, 22V, 22
The terminal voltages UOUT, VOUT, WOUT of W are taken in for a period exceeding a predetermined threshold value (for example, E / 2), and the process proceeds to step S28.

Then, in step S28, it is determined whether or not the rotation speed N of the motor 11 is equal to or higher than a predetermined rotation speed #N. If the result of this determination is "NO", then a series of processing is terminated. On the other hand, if the result of this determination is "YES", then the operation proceeds to step S29.

Then, in step S29, a signal indicating the execution of the edge detection interrupt processing is output, a predetermined first timer value α is set in the timer, and the control stage is set at this time. Each pulse UH, V
An on / off pattern for H, WH, UL, VL, and WL is output to drive the motor 11 to rotate, and the process proceeds to step S30. Then, in step S30, "0" is set to the flag value of the activation flag F_ST, and the series of processes is ended.

In this edge detection interrupt processing, the first timer value α set in the timer is set to an appropriate value between 0 and T / 2 in accordance with various control parameters, for example. It is possible to change the period from the control stage set at the time point until the control stage is switched to the next control stage, and accordingly, the drive control executed after the end of the control for forcibly rotating the motor 11 (that is, COMM With respect to the start of the excitation switching operation based on the signal), it is possible to advance the electrical angle from 0 to 30 °.

Hereinafter, the timer interrupt process which is repeatedly executed at predetermined time intervals will be described. First, FIG.
In step S31 shown in step S31, a signal indicating execution of the timer interrupt process is output and the start flag F_ST is output.
It is determined whether the flag value of 1 is "1". If the result of this determination is "NO", then step S4 shown in FIG.
Go to 2. On the other hand, if the result of this determination is "YES", then the flow proceeds to step S32, and the starting DUTY when the motor 11 is started is set. Then, in step S33, the start-up timer value S that has been appropriately set in advance is set in the timer.

Next, in step S34, any one of the control stages ST1, ..., ST6 is selected as the startup control stage, and each pulse UH, VH, WH, UL, corresponding to the set startup control stage is selected. An on / off pattern for VL and WL is output, and the motor 11 is forcibly rotationally driven according to the starting DUTY set in step S32. Then, in step S35, for example, the number of times the motor 11 makes one rotation MN is counted.

Then, in step S36, it is determined whether or not the number MN of one rotation of the motor 11 is less than or equal to a predetermined number #MN (for example, # MN = 10). If the result of this determination is “YES”, the flow proceeds to step S40 described below. On the other hand, if the result of this determination is "NO", then the operation proceeds to step S37, the count value of the number MN of one rotation of the motor 11 is set to zero, and the operation proceeds to step S38.

In step S38, for example, the state when the motor 11 is started (for example, the rotation speed N, the motor torque Tor, the temperature Tmag, each phase voltage, each phase current, etc.).
Each pulse UH, VH, WH, U preset according to
The duty ratio DUTY of L, VL, and WL is searched by a map search or the like, and is newly set as the starting DUTY, and the process proceeds to step S39. Then, in step S39, for example, the state at the time of starting the motor 11 (for example,
The preset timer value according to the rotation speed N, the motor torque Tor, the temperature Tmag, each phase voltage, each phase current, etc.) is searched by a map search or the like, and is newly set as the startup timer value S, and the process proceeds to step S40. move on.

In step S40, any of the control stages ST1, ..., ST6 is set as the startup control stage. Then, in step S41, a predetermined starting timer value S is set in the timer and each pulse UH, VH, WH, UL, V corresponding to the starting control stage is set.
An ON / OFF pattern for L and WL is output, the motor 11 is forcibly rotationally driven according to the starting DUTY set in step S32, and a series of processes is ended.

On the other hand, in step S42 shown in FIG. 7, is the output of the signal indicating the execution of the timer interrupt processing the first output after the signal indicating the execution of the edge detection interrupt processing is output? Determine whether or not. This judgment result is "N
In the case of “O”, the process proceeds to step S45 described later. On the other hand, if the result of this determination is "YES", then step S
In step 43, the motor output calculation DUTY calculated based on various control parameters is set, and any one of the control stages ST1, ..., ST6 is selected. Next, in step S44, the timer is set to the second value equal to the cycle T.
The timer value T is set, and an ON / OFF pattern for each pulse UH, VH, WH, UL, VL, WL is output according to the operation DUTY set in step S43 and the selected control stage, and the motor 11 Is rotationally driven, and a series of processing is completed.

On the other hand, in step S45, it is determined whether the output of the signal indicating the execution of the timer interrupt processing is the second output after the signal indicating the execution of the edge detection interrupt processing is output. To do. If the result of this determination is "NO", the flow proceeds to step S48 described below. On the other hand, if the result of this determination is "YES", then the operation proceeds to step S46,
The motor output calculation DUTY calculated based on various control parameters is set, and each control stage ST1,
,, ST6 is selected. Then, step S47
In, in the timer, for example, ON / OFF of the COMM signal
A predetermined third timer value β that is longer than the OFF cycle and less than T / 2 is set, and each pulse UH, VH, WH is set according to the operation DUTY set in step S46 and the selected control stage. , UL, VL, and WL are output, the motor 11 is rotationally driven, and a series of processing is completed.

On the other hand, in step S48, the edge detection interrupt processing is permitted, the process proceeds to step S49, the counter value of the read counter CR is set to zero, and the step S49 is executed.
Proceeding to 50, the operation of the timer is stopped, and the series of processing is terminated.

For example, at the time t0 shown in FIG. 8, the starting process is executed for the motor 11 in the stopped state, and each control stage ST is operated for the period of the predetermined starting timer value S.
1, ..., ST6 (for example, the fourth control stage S
T4) is set as the control stage at startup, and the startup DUT
Each pulse UH, depending on Y and the startup control stage
The ON / OFF patterns for VH, WH, UL, VL, and WL are output to perform initial excitation, and the motor 11 is forcibly driven to rotate. Then, at a time t1 when a predetermined start timer value S has elapsed from the time t0, a timer interrupt process is executed, and the start control stage is set to one of the other control stages ST1, ..., ST6 (for example, the fifth control stage ST5. ).

Then, at a time t2 when a predetermined start timer value S has elapsed from the time t1, a timer interrupt process is executed, and the start control stage is changed to another control stage ST.
1, ..., ST6 (for example, the sixth control stage S
Switch to T6). At this time, when the U-phase low-side switching element SUL is turned off and the V-phase low-side switching element SVL is turned on, the energization state is switched, so that the armature coils 22U, 22V, 22 are turned on.
A spike voltage is generated in the combined voltage obtained by combining the W terminal voltages UOUT, VOUT, and WOUT, and a COMM signal of logical “high” level, that is, spike noise is output.

Then, at time t3 when half of the predetermined start-up timer value S (that is, S / 2) has elapsed from time t2, the set control stage (for example, the sixth stage) is set.
When the terminal voltage (for example, the U-phase terminal voltage UOUT of the U-phase armature coil 22U) of the non-energized phase armature coil in the control stage ST6) exceeds a predetermined threshold value (for example, E / 2), the COMM signal Goes from a logic "low" level to a "high" level. However, at this time t3, for example, the rotation speed N of the motor 11 is less than the predetermined rotation speed #N,
Since the state of the motor 11 has not reached the predetermined state, the edge detection interrupt process is not executed and the control for forcibly rotating the motor 11 is continued.

Then, at a time t4 when a predetermined start timer value S has passed from the time t2 and at a time t6 when a predetermined start timer value S has passed from the time t4, a timer interrupt process is executed to start the start control stage. Any of the other control stages ST1, ..., ST6 (for example, sequentially,
Switching to the first control stage ST1 and the second control stage ST2).

Then, at time t7 when half the predetermined start timer value S (that is, S / 2) has elapsed from time t6, the set control stage (for example, the second
When the terminal voltage (for example, the V-phase terminal voltage VOUT of the V-phase armature coil 22V) of the non-energized phase armature coil in the control stage ST2) exceeds a predetermined threshold value (for example, E / 2), the COMM signal Goes from a logic "low" level to a "high" level. At time t7, for example, the motor 1
If the rotation speed N of the motor 1 is greater than or equal to the predetermined rotation speed #N,
Since the state 1 has reached the predetermined state, the edge detection interrupt process is executed. And the rotor 2 of the motor 11
According to the COMM signal related to the magnetic pole position of 1, for example, a predetermined first timer value α is set in the timer as the time until the excitation switching operation for sequentially switching and setting the six control stages ST1, ..., ST6 is started. Set. After time t6, when the motor 11 is rotated a number of times exceeding the predetermined number #MN by the control of forcibly rotating the motor 11, the rotation number N of the motor 11 is less than the predetermined rotation number #N. In this case, the startup DUTY and the startup timer value S are changed, and the control for forcibly rotating the motor 11 is executed again.

Then, as shown in FIG. 8 and FIG. 9, at time t7 when a predetermined first timer value α has elapsed from time t7.
8, the excitation switching operation based on the rising edge of the COMM signal detected at time t7 (for example, the second
Switching from the control stage ST2 to the third control stage ST3) is performed. At this time, after outputting the signal indicating the execution of the edge detection interrupt processing, the signal indicating the execution of the first timer interrupt processing is output and the control stage after switching (for example, the third control stage ST3). CO
In order to maintain the edge interval time (cycle) T of the MM signal, the timer is set to a second timer value T which is equivalent to the cycle T. At the time t7 described above, the first timer value α is set to 1/2 of the edge interval time (cycle) T.
When set to (that is, T / 2), the advance angle becomes an electrical angle of 0 ° with respect to the start of the excitation switching operation based on the COMM signal, but the first timer value α is set to 0 ≦ α ≦ T / 2. By setting it appropriately, for example, a maximum electrical angle of 30 °
A lead angle of up to (α = 0) is possible.

Then, at time t10 when a predetermined second timer value T has passed from time t8, the excitation switching operation (for example, switching from the third control stage ST3 to the fourth control stage ST4) is executed. As a result, one C
The excitation switching operation is executed twice based on the edge detection interrupt processing of the OMM signal. At this time, after outputting the signal indicating the execution of the edge detection interrupt processing, the signal indicating the execution of the second timer interrupt processing is output and the edge detection interrupt processing is executed by the spike noise generated at the time of switching. In order to prevent this, a predetermined third timer value β which is longer than the ON / OFF cycle of the COMM signal and less than T / 2 is set in the timer as a period for prohibiting the input of the COMM signal. To do. This allows
For example, when the U-phase low-side switching element SUL is turned off and the V-phase low-side switching element SVL is turned on, the energization state is switched, and the terminal voltage UOUT of each armature coil 22U, 22V, 22W, VOU
Even if a spike voltage is generated in the combined voltage obtained by combining T and WOUT and a logic "high" level COMM signal, that is, spike noise is output, the input of this signal is prohibited.

Then, at time t11 when a predetermined third timer value β has elapsed from time t10, a signal indicating execution of the third timer interrupt processing after outputting a signal indicating execution of the edge detection interrupt processing. , The input of the COMM signal is permitted, and the operation of the timer is stopped. Then, as at time t12, the terminal voltage of the armature coil in the non-energized phase in the set control stage (for example, the fourth control stage ST4) (for example, the W-phase terminal voltage WOUT of the W-phase armature coil 22W). ) Exceeds a predetermined threshold value (for example, E / 2) and the COMM signal changes from the logic “low” level to the “high” level, the time until the next excitation switching operation is started is set to a predetermined value. The first timer value α is set in the timer.

The first timer value α, the second timer value T, the third timer value β, and COM are then processed similarly to the processing executed from the time t7 to the time t12.
Based on the timing of detecting the rising edge of the M signal, the excitation switching operation of sequentially switching and setting the six control stages ST1, ..., ST6 is continued. In addition,
When switching the energization state of each of the high side switching elements SUH, SVH, SWH (for example, at times t8, t13, t18).
Etc.), each low side switching element SUL, SVL,
When switching the energization state of the SWL (for example, at times t10 and t1)
5, t20, etc.), spike noise occurs. However, each high side switching element SUH, SVH, SW
At the time of switching the energized state of H, a series of ON / OFF repetitions in the COMM signal is continued, that is, the armature coils 22U, 22V, 22W of the non-energized phase in each control stage ST1, ..., ST6. Each terminal voltage UOUT,
Since VOUT and WOUT are included in a period exceeding a predetermined threshold value (for example, E / 2), it is set not to execute the process of inhibiting the input of the COMM signal.

As described above, according to the brushless DC motor control device 10 and the brushless DC motor starting method according to the present embodiment, each control stage ST.
1, ..., ST6 are sequentially switched and set, and when the motor 11 is forcibly driven to rotate, the duty ratio DUTY of pulse width modulation (PWM) is gradually changed, and the switching cycle of the excitation switching operation (that is, , Motor 11
By changing the starting rotation speed of the motor 11 according to the state of the motor 11, the motor 11 can be started quickly and reliably even when, for example, the secular change of the motor 11 or the fluctuation of the load during driving occurs. Can be made. Further, after the motor 11 is started, the control stages ST1, ..., ST6 are sequentially switched and set according to the magnetic pole position of the rotor 21 of the motor 11, and when performing the excitation switching operation, for example, a Hall element or the like is used. The drive control of the motor 11 can be accurately performed based on the detection of the rising edge of the COMM signal without the need to provide a position detecting device for detecting the magnetic pole position.

Moreover, the excitation switching operation can be controlled twice based on the first timer value α and the second timer value T with reference to the edge detection interrupt processing of the COMM signal once. By setting the first timer value α to an appropriate value between 0 and T / 2, it becomes possible to control the advance angle up to an electrical angle of 0 to 30 °. Furthermore, the third timer value β
By setting the period during which the input of the COMM signal is prohibited, the low-side switching elements SUL and SV are set.
It is possible to prevent the edge detection interrupt processing from being executed by spike noise generated when the energization states of L and SWL are switched, and it is possible to appropriately drive and control the motor 11 according to the COMM signal.

In the above embodiment, the position reference signal generator 13 sets E / 2 as the predetermined threshold value for the combined voltage when the COMM signal of the logic "high" level (ON) is output. The value is not limited to this, and may be set to another value. For example, if the predetermined threshold value is set to a value smaller than E / 2, the timing at which the rising edge of the COMM signal is detected becomes earlier, so that the advance angle can be made larger.

[0065]

As described above, according to the method for driving a brushless DC motor of the present invention as set forth in claim 1, two times are set on the basis of the timing when the terminal voltage of the stator winding becomes equal to or higher than a predetermined threshold value. The energization switching can be performed, and by repeating the processing from the first step to the third step, it is possible to maintain appropriate drive control according to the magnetic pole position of the rotor, and stabilize the brushless DC motor. It can be driven.

Furthermore, according to the method of driving the brushless DC motor of the present invention as defined in claim 2, the execution of the first step is restricted by controlling the execution of the first step over the period in which the counting of the third timer value is executed. It is possible to reliably prevent the counting of the first timer value from being started due to the spike noise generated by the counter electromotive voltage at the time of switching, and it is possible to appropriately drive the brushless DC motor.
Furthermore, according to the brushless DC motor driving method of the present invention as set forth in claim 3, advance control becomes possible by changing the first timer value, and for example, the first timer value is changed to a relatively small value. As a result, the timing of executing the first energization switching and the timing of executing the second energization switching can be advanced with reference to the timing when the terminal voltage of the stator winding becomes equal to or higher than the predetermined threshold value.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a controller for a brushless DC motor that realizes a method for starting a brushless DC motor according to an embodiment of the present invention.

FIG. 2 is a timing chart showing an operation of a switching element in each control stage.

3A to 3F are schematic diagrams showing the operation of the motor in each control stage shown in FIG.

FIG. 4 is a flowchart showing an operation of the controller of the brushless DC motor shown in FIG. 1, particularly a starting process.

5 is a flowchart showing an operation of the controller for the brushless DC motor shown in FIG. 1, particularly an edge detection interrupt process.

FIG. 6 is a flowchart showing an operation of the controller of the brushless DC motor shown in FIG. 1, particularly a timer interrupt process.

FIG. 7 is a flowchart showing an operation of the controller for the brushless DC motor shown in FIG. 1, particularly a timer interrupt process.

FIG. 8 is a diagram showing an example of a timing chart showing the execution timing of each process shown in FIGS. 4 to 7;

9 is an enlarged view of a main part of the timing chart shown in FIG.

[Explanation of symbols]

10 Brushless DC Motor Control Device 11 Motor (Brushless DC Motor) 12 Motor Drive Unit (Electrification Switching Means) 13 Position Reference Signal Generation Unit (Position Reference Signal Output Means) 22U U-Phase Armature Coil (Stator Winding) 22V V Phase armature coil (stator winding) 22W W phase armature coil (stator winding) Step S24 Output frequency detecting means Step S29 First counting means,
Timer value changing means Step S43 and Step S44 First switching control means Step S46 Second switching control means Step S26 and Step S47 Restricting means Step S48 Restricting releasing means

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tsukasa Naganuma             Saginoya Higashi, Hoshoji Temple, Takanezawa Town, Shioya District, Tochigi Prefecture             Address 2021 Keihin Tochigi Development Center Co., Ltd.             In the center (72) Inventor Takaharu Sugawara             Saginoya Higashi, Hoshoji Temple, Takanezawa Town, Shioya District, Tochigi Prefecture             Address 2021 Keihin Tochigi Development Center Co., Ltd.             In the center F term (reference) 5H560 BB04 BB07 BB12 DA13 DC13                       EB01 EB05 EC10 TT01 TT07                       UA05 XA03 XA11 XA12 XB08                       XB10

Claims (3)

[Claims] 1. A rotor having a permanent magnet, and a stator winding of a plurality of phases for generating a rotating magnetic field for rotating the rotor, wherein one end of each stator winding of the plurality of phases is commonly connected. A method of driving a brushless DC motor having a plurality of switching elements, wherein the brushless DC motor is rotationally driven by an energization switching unit that sequentially commutates the energization of the stator winding. A first step of starting counting of a first timer value when the terminal voltage of is equal to or higher than a predetermined threshold value; and, when the counting of the first timer value is completed, the energization switching means transfers the current to the stator winding. In the second step of starting the counting of the second timer value, and when the counting of the second timer value is completed, the energization switching means transfers the current to the stator winding. Let first A method of driving a brushless DC motor, comprising: three steps. 2. A fourth step of restricting execution of the first step and starting counting of a third timer value when counting of the second timer value is finished, and counting of the third timer value. When finished, the first
The brushless D according to claim 1, further comprising a fifth step of releasing restriction on execution of the step.
C motor driving method. 3. The method of driving a brushless DC motor according to claim 1, further comprising a sixth step of changing the first timer value.