JP2008035623A - Controller of brushless motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To switch electricity application correctly even if noise is superimposed on a signal for detecting a rotor position. <P>SOLUTION: In response to an interruption request generated every time when an edge is detected by a position sensor 3, this controller 1 executes processing for detecting the rotor position of a brushless motor 2 at a positional information acquiring section 12. The controller 1 further comprises an interruption request control section 11. After the lapse of an inhibiting time during which measurement is started by means of a timer at a section 31 for determining the elapse of sensor signal variation detection inhibiting time when a drive signal is outputted to an inverter circuit 4, the interruption request control section 11 clears the interruption request. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a brushless motor control device.

When controlling a brushless motor, it is known to provide a hall element for detecting the rotational position of the rotor and determine the switching timing of the energized phase to the brushless motor based on the sensor signal of the hall element. Here, since the switching timing of the energized phase is performed by detecting the switching of the edge of the sensor signal, it seems that the signal pattern of the sensor signal is switched when noise occurs in the sensor signal of the Hall element. May be input to the control device.
In this case, since an incorrect energization pattern is input to the brushless motor, the conventional brushless motor control device stores in advance the signal pattern assumed as the sensor signal of the Hall element and its appearance order, and the sensor signal There is a configuration in which noise is removed by determining whether the appearance order of signal patterns is correct when the signal pattern changes, that is, by determining the continuity of the signal pattern (see, for example, Patent Document 1).
JP 2004-254467 A

However, depending on the generation timing of noise, there is a possibility that a signal that apparently switches the signal pattern of the sensor signal and that satisfies the continuity with respect to the previous signal pattern may be generated. In this case, since the continuity is satisfied, the energized phase is switched at an earlier timing than originally intended.
The present invention has been made in view of such circumstances, and a main object of the present invention is to enable correct energization switching even when noise is applied to a signal for detecting the position of the rotor.

  According to a first aspect of the present invention for solving the above-mentioned problems, a position detection sensor for detecting a position of a rotor of a brushless motor and outputting position information is connected to an inverter circuit, and the rotation control of the brushless motor is performed. A position information acquisition unit that acquires position information output by the position detection sensor and creates position information at the time of change from a signal pattern of position information acquired at the time of change of the position information. And a position information storage unit for determination that stores the signal pattern of the position information as position information at the time of determination, and the position information at the time of change and the position information at the time of determination determined in the previous process are compared. Change-time position information determination means for determining whether or not the signal pattern can occur continuously in the rotation direction, final position information determined in the current process, and previous time Compared with the position information at the time of determination determined by the process, and determines whether or not both are the same or a signal pattern that is continuous in the rotation direction of the rotor, When it is determined that the change-time position information is a signal pattern that is continuous in the rotation direction of the rotor with respect to the fixed position information that has been confirmed, and the current position information that has been confirmed in the previous process When it is determined that the fixed position information determined by the process is the same or a signal pattern that continues in the rotation direction of the rotor, the drive signal for switching the pattern for energizing the brushless motor from the inverter circuit is updated. Drive signal output means for interrupting, and interrupt request control means for prohibiting the creation of position information at the time of change and position information at the time of confirmation for a predetermined time after the drive signal is switched. And a control device for a brushless motor according to claim.

  When this brushless motor control device outputs a drive signal to the inverter circuit so as to switch the energization phase of the brushless motor, the energization phase switching control is performed even if the rotor position information changes for a predetermined time thereafter. Not performed.

According to a second aspect of the present invention, in the brushless motor control device according to the first aspect, the fixed position information is position information when a plurality of pieces of position information acquired at different times coincide with each other. And
In this brushless motor control device, if the output of the position detection sensor contains noise with a short occurrence time, the multiple pieces of position information obtained by shifting the time will not match. It is not handled as time position information. For this reason, it is possible to prevent the conduction phase from being switched by noise having a short generation time.

  According to the present invention, the switching of the energized phase due to noise is prevented from the continuity and identity of the output of the position detection sensor, and when noise occurs in a certain time after the energized phase is switched, By prohibiting creation of position information at the time of confirmation, switching of the energized phase is prevented even when noise that satisfies continuity occurs immediately after switching. Thereby, the noise resistance performance of the brushless motor can be improved.

The best mode for carrying out the invention will be described in detail with reference to the drawings.
As shown in FIG. 1, the brushless motor control device 1 performs energization control based on the detection result of the rotational position of the rotor of the brushless motor 2 by the position detection sensor 3, and outputs a drive signal for the inverter circuit 4. Thus, the current supplied to the brushless motor 2 from the power source 5 is switched.

  Here, the brushless motor 2 includes a stator and a rotor as main components. A stator is formed by winding three stator windings U, V, and W around the stator. The stator windings U, V, W are connected by so-called delta connection or star connection. The rotor includes a rotation shaft and a permanent magnet in which a plurality of magnetic poles (N pole and S pole) are arranged along the circumferential direction of the rotation shaft. The brushless motor may be an inner rotor type or an outer rotor type.

  As the position detection sensors 3, for example, a Hall IC (Integrated Circuit) including a Hall element and an electronic circuit is used, and three position detection sensors 3 are arranged at positions where the rotation position of the rotor can be detected. An example of sensor signals output from these position detection sensors 3 is shown in FIG. In FIG. 2, the horizontal axis represents an electrical angle, and the outputs of the position detection sensors 3 corresponding to the U phase, the V phase, and the W phase are arranged in the vertical direction. The output of each position detection sensor 3 is periodically switched between a high level (H) and a low level (L). The rotational position of the rotor can be specified by a combination of these three signal levels.

  The inverter circuit 4 is, for example, a circuit configured by connecting six switching elements two by two between the positive and negative terminals of the power supply 5, and the DC voltage supplied from the power supply 5 is input from the control device 1. The brushless motor 2 is driven by converting into an AC voltage based on the pulse width modulation waveform signal (drive signal).

The control device 1 is configured such that a sensor signal output from the position detection sensor 3 is input to an interrupt request control unit 11 (interrupt request control unit) and a position information acquisition unit 12 (position information acquisition unit).
The position information acquisition unit 12 is configured to receive, in addition to the sensor signal, a rotation command signal detection unit 21 that receives a rotation start command output from an external ECU, and information on each unit. The position information acquisition unit 12 has three memories (first memory, second memory, and third memory). When an interrupt request is input from the interrupt request control unit 11, the three position detection sensors 3 output 3 The sensor signals for the phases are stored in the order of the first memory, the second memory, and the third memory every time interval (for example, several tens of μs) as one position information. The interrupt request is a command for newly requesting the position information acquisition unit 12 to start acquisition of a sensor signal when an edge of the sensor signal is detected.

  When the position information stored in the first memory is different from the previously stored sensor signal, the position information acquisition unit 12 uses the one set of sensor signals at that time as position information at the time of change, and a determination unit for determining the position information at startup 13 is output. Further, when the position information stored in the first memory to the third memory matches, the position information is output as confirmed position information to the confirmed position information storage unit 14 (determined position information storage means). Note that if the position information stored in any of the memories has changed due to noise, the three pieces of position information become inconsistent, so that the position information is taken again. As a result, noise generated during the acquisition of the position information into the three memories is removed.

The startup position information finalized determination unit 13 determines whether or not the startup position information has been determined. If so, the change-time position information continuity determination unit 15 (change-time position information determination means) Execute the process.
The change-time position information continuity determination unit 15 determines continuity between the change-time position information input this time and the fixed-time position information that has already been determined last time. When both satisfy the continuity, the change position information is output to the drive signal output unit 16.

The fixed position information storage unit 14 has a memory for storing fixed position information, and is connected to the startup position information fixed determination unit 17.
The startup position information confirmed determination unit 17 is connected to the drive signal output unit 16 via the startup position information determination unit 18 and is also connected to the determined position information continuity determination unit 19 (one information determination unit at determination). It is connected, and it is determined whether or not the rotational position of the rotor when the brushless motor 2 is started is fixed.
The startup position information determination unit 18 performs processing for determining the current determination position information as the startup position information and storing it in the memory, and outputs the determination position information to the drive signal output unit 16.

  The fixed position information continuity determination unit 19 performs processing for determining the continuity of the position information, and is connected to the drive signal output unit 16 and the fixed position information identity determination unit 20. The continuity is determined by energizing the sensor pattern 0, sensor pattern 1,..., Sensor pattern 5 in the order of the predetermined sensor pattern as shown in FIG. For example, if a sensor signal corresponding to sensor pattern 1 is input next to a set of sensor signals corresponding to sensor pattern 0, it is considered that continuity has been established, and the drive signal output unit 16 determines Output location information. On the other hand, for example, if a position detection signal corresponding to the sensor pattern 5 is input after a set of sensor signals corresponding to the sensor pattern 0 in FIG. .

  The fixed position information identity determination unit 20 performs processing when the fixed position information continuity determination unit 19 does not recognize continuity, and the fixed position information that has already been determined last time and the fixed time that has been determined this time. Compare with location information. When both pieces of position information match, it is regarded that the identity is established, and the determined position information is output to the drive signal output unit 16. If the position information does not match, the continuity or identity of the confirmed position information is not recognized. Therefore, the processing of the drive signal output unit 16 is performed by resetting the position information held by the position information acquisition unit 12. Is not executed.

  The drive signal output unit 16 is connected to the inverter circuit 4 and the sensor signal change detection prohibition time elapse determination unit 31 of the interrupt request control unit 11. The drive signal output unit 16 sequentially generates drive signals for setting energization patterns to be input to the brushless motor 2 through the inverter circuit 4. When the change position information and the fixed position information input to the drive signal output unit 16 satisfy continuity, a drive signal for switching the energization pattern is output. If the fixed position information satisfies the same, a drive signal that maintains the current energization pattern is output.

  The interrupt request control unit 11 includes a sensor signal change detection prohibition time elapse determination unit 31, a sensor signal edge request change interrupt request clear unit 32, a sensor signal edge change interrupt request generation unit 33, and a sensor signal change detection unit 34. Have. The sensor signal change detection prohibition time elapse determination unit 31 includes a timer that counts a time during which the interrupt processing at the edge change is prohibited from the switching timing of the energized phase. The data is output to the clear unit 32 and the process of the sensor signal edge request change interrupt request clear unit 32 is executed. When the sensor signal change detection unit 34 detects an edge change of the sensor signal of the position detection sensor 3, the sensor signal edge change interrupt request generation unit 33 generates an interrupt request. The sensor signal edge request change interrupt request clear unit 32 outputs a signal for clearing the interrupt request generated in the sensor signal edge change interrupt request generation unit 33 when the prohibition time has elapsed. The sensor signal edge change interrupt request generation unit 33 causes the position information acquisition unit 12 to execute processing for an interrupt request generated after the sensor signal edge change interrupt request clear unit 32 clears the interrupt request.

Next, a specific example of processing in this embodiment will be described with reference mainly to the flowcharts of FIGS.
First, when the power is turned on (Yes in step S101) and a rotation command signal is input to the position information acquisition unit 12 (Yes in step S102), the position information acquisition unit 12 outputs a set of sensor signals of the position detection sensor 3. The first position information (pattern 1) is stored in the first memory (step S103). At this time, the counter inside the position information acquisition unit 12 is set to “1” (step S104). At the same time, a position information acquisition waiting time timer is started (step S105).

  When the position information waiting time elapses (Yes in step S106), one set of sensor signals of the position detection sensor 3 is stored in the second memory as the second position information (pattern 2) (step S107), and the position information acquisition unit The internal counter of 12 is incremented by 1 to “2” (step S108). At this stage, since the counter has not reached the predetermined value (in this case, “3”) (No in step S109), the position information acquisition waiting time timer is started again (step S110). The above-described processing (step S106 to step S108) is performed, and the sensor signal of the position detection sensor 3 is stored in the third memory as the third position information (third pattern). Since the value of the counter becomes “3”, the process proceeds from step S109 to step S111 to determine whether or not all three patterns acquired as position information match.

  If any of the position information does not match (No in step S111), the position information stored as pattern 2 is held again as pattern 1 (step S112), and the position information stored as pattern 3 is the pattern. 2 is held again (step S113). After changing the counter to “2” (step S114), a timer for the position information acquisition waiting time is started in order to newly acquire the third position information (step S115). Then, the above-described processing (from step S106 to step S115) is repeated until all the three pieces of position information acquired by shifting the time match.

When all the three pieces of position information acquired by shifting the time in step S111 match, the fixed position information storage unit 14 stores the position information as fixed position information (step S116). The information stored at this time is used as the position information that has already been confirmed in the previous processing.
Next, the starting position information finalized determination unit 17 determines whether or not the starting position information has been determined and saved (whether it is a signal pattern at starting or starting position information). Is the signal pattern after determining (step S117). If the starting position information is not confirmed (No in step S117), it is assumed that the confirmed position information that has been confirmed and saved this time is not a signal pattern after the starting position information is confirmed, but a signal pattern at the time of activation. Then, the position information is determined as position information at the time of activation (step S118), and the drive signal output unit 16 updates the drive signal (step S120). At the time of start-up, since there is no original signal to be updated, a drive signal is newly output.

  On the other hand, if the position information at the time of activation has already been confirmed (Yes in step S117) as in the second and subsequent processes, the position information at the time of confirmation / saved this time is the signal pattern at the time of activation. It is assumed that the signal pattern is obtained after the position information at startup is determined. And it is determined whether the pattern of the position information at the time of determination is the same or continuous (step S119). The fixed position information continuity determining unit 19 and the fixed position information identity determining unit 20 compare the fixed position information determined and stored this time with the fixed position information determined and stored last time, and both are the same. Alternatively, it is determined whether or not the signal pattern is continuous in the rotation direction of the rotor of the brushless motor 2, that is, whether or not the continuity of the signal pattern occurs in the order shown in FIG. If the same or continuity is recognized, the drive signal output unit 16 updates the drive signal (step S120).

When the same or continuity is not recognized in step S119, after outputting or updating the drive signal in step S120, and when the position information acquisition waiting time has not elapsed in step S106, the process proceeds from terminal C and terminal D. In step S121, the position information acquisition unit 12 determines whether or not the signal pattern output from the position detection sensor 3 has changed.
When the signal pattern has not changed (No in step S121), the position information acquisition unit 12 determines whether or not the position information acquisition waiting time timer is operating (step S122), and when the timer is not operating (step S122). NO at S122), the process returns to step S121. On the other hand, if the timer is operating (YES in step S122), the process returns from terminal B to step S106, and the position information acquisition unit 12 repeats the above processing.

  If the signal pattern has changed in step S121 (Yes in step S121), the interrupt request control unit 11 checks whether an interrupt request accompanying an edge change has occurred (step S123). If no interrupt request has occurred (No in step S123), the process returns from terminal A to step S106 and waits for the elapse of the position information acquisition wait time. On the other hand, if an interrupt request has occurred in the interrupt request control unit 11 (Yes in step S123), the position information acquisition unit 12 is a set of sensor signals of the position detection sensor 3, and is stored in the first memory. The obtained position information is obtained and used as change position information (step S124). Next, the position information acquisition unit 12 resets the counter to “1” (step S125) and starts a timer for the position information acquisition waiting time (step S126).

  Then, the startup position information confirmed determination unit 13 determines whether or not the startup position information has been confirmed for the change-time position information acquired this time (step S127). When the starting position information has been confirmed (YES in step S22), the changing position information continuity determination unit 15 compares the changing position information acquired this time with the previously determined and stored confirmed position information, It is determined whether or not both are signal patterns that are continuous in the rotation direction of the rotor of the brushless motor 2, that is, whether or not continuity of the signal patterns occurs in the order shown in FIG. 2 (step S128). When the continuity of the signal pattern is satisfied (Yes in step S128), the drive signal is updated (step S129). If the continuity of the signal pattern is not satisfied (No in step S128), the process returns to step S123.

  After updating the drive signal in step S129, the sensor signal change detection prohibition time passage determination unit 31 receives a command from the drive signal output unit 16 and starts a timer for measuring the sensor signal detection prohibition time (step S130). . The sensor signal detection inhibition time is set to several μs to several tens of μs. This value may be set to the time required for the energized phase switching process (for example, about 50 μsec), or may be set to a time not related to the switching process. When the sensor signal detection prohibition time has passed (Yes in step S131), the sensor signal edge change interrupt request clearing unit 32 clears the edge change interrupt request of the sensor signals of all phases (step S132). In this case, in step S123, which returns from step S132, it is determined that no interrupt request has occurred, and the process returns to step S106. Therefore, the position information acquisition unit 12 starts over from the acquisition of the second position information.

Here, an example of processing from step S106 to step S129 is shown in FIG. When the edge of the W-phase position detection sensor 3 is detected at time t1, the interrupt request control unit 11 generates an interrupt request. The position information acquisition unit 12 acquires pattern 1. Since the pattern 1 is a signal corresponding to the sensor pattern 4 (U phase: H, V phase: L, W phase: L), an energized phase switching process corresponding to the sensor pattern 4 is performed. Thereafter, patterns 2 and 3 are acquired at time t2 and time t3, respectively, after a predetermined time has elapsed. Since these three patterns are the same, the sensor pattern 4 serves as a definite position signal, and here again the process of switching the energized phase corresponding to the sensor pattern 4 is performed. On the other hand, when noise S _N 1 is generated in the sensor signal in the V-phase position detection sensor 3 at time t4, the interrupt request control unit 11 detects the edge of the noise S _N 1 and generates an interrupt request. As a result, the position information acquisition unit 12 acquires position information (pattern 1) in the first memory. The position information in the first memory is a signal corresponding to the sensor pattern 5 (U phase: H, V phase: H, W phase: L). Thereafter, the patterns 2 and 3 of the second memory and the third memory are acquired at time t5 and time t6 after a predetermined time has elapsed. Since the pattern 1 is different from the patterns 2 and 3, the position information due to the noise S _N 1 is discarded. Thereby, switching of the energized phase due to an erroneous signal is prevented. A pattern is acquired again at time t7 after the elapse of a predetermined time, and the sensor pattern 4 becomes a fixed position signal when all the patterns acquired at time t5, time t6, and time t7 match. Since the identity with the position signal previously determined in step S119 is established, an energized phase switching process corresponding to the sensor pattern 4 is performed in step S120. Even if an erroneous drive signal is output to the actual position of the rotor due to continuous noise, the correct drive signal can be restored when the position signal is determined.

An example of the process performed in step S119 will be described with reference to FIG. In the signal pattern of stage 2, when noise S _N 2 is superimposed and becomes a sensor signal of stage 1 as shown by a broken line, stage 1 is supposed to be stage 3 after stage 2. Then, since the continuity is not satisfied, the drive signal update process is not performed.
Furthermore, FIG. 5 shows an example of processing from step S129 to step S132. When an edge of the W-phase position detection sensor 3 is detected at time t11, an interrupt request due to the W-phase is generated. While a drive signal is created based on this edge and switching of the energized phase is performed, noise S _N 3 is generated in the V-phase position detection sensor at time t12. An interrupt request due to the V phase is generated by the edge of the noise S _N 3, but since the time t12 is within the range of the sensor signal change detection prohibition time Tw, after the sensor signal change detection prohibition time Tw has elapsed, The resulting interrupt request is cleared. As a result, switching of the energized phase due to noise S _N 3 is prevented.

According to this embodiment, when the edge of the sensor signal is switched, the energized phase switching process is performed only when the continuity of the pattern can be confirmed. It is possible to prevent output of the drive signal.
When the edge of the sensor signal is switched and the continuity of the pattern is satisfied, the edge interrupt request is cleared during the predetermined sensor signal change detection prohibition time Tw. When noise occurs at a relatively early stage, it is possible to prevent the drive signal from being switched at an incorrect timing due to such noise.
After the sensor signal change detection prohibition time Tw elapses, the sensor pattern continues for the filter time, and the drive signal is updated when the sensor pattern satisfies the same or continuity. The influence can be removed and the reliability can be improved.

Note that the present invention can be widely applied without being limited to the above-described embodiment.
For example, the number of pieces of position information is not limited to three as long as it is plural. The energization control may be performed based on only one of the fixed position information and the changed position information.

It is a block diagram of a control device of a brushless motor according to an embodiment of the present invention. It is a chart which shows the pattern of the sensor signal output from a position detection sensor. It is a flowchart explaining the process of the control apparatus of a brushless motor. It is a flowchart explaining the process of the control apparatus of a brushless motor. It is a figure explaining the specific example of the process of step S106 to step S129. It is a figure explaining the specific example of the process from step S129 to step S132.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Control apparatus 2 Brushless motor 3 Position detection sensor 4 Inverter circuit 11 Interrupt request control part (interrupt request control means)
12 position information acquisition unit (position information acquisition means)
14 Confirmation position information storage unit (confirmation position information storage means)
15 Change position information continuity determination unit (change position information determination means)
19 Position information continuity determination unit at the time of determination (one information determination means at the time of determination)

Claims (2)

A position detection sensor that detects the position of the rotor of the brushless motor and outputs position information and an inverter circuit are connected, and is a brushless motor control device that controls the rotation of the brushless motor,
Position information acquisition means for acquiring position information output by the position detection sensor and creating position information at the time of change from a signal pattern of position information acquired at the time of change of the position information;
A position information storage unit at the time of storing the signal pattern of the position information as position information at the time of determination;
Change-time position information determination that compares the change-time position information with the fixed-time position information determined in the previous process and determines whether or not both are signal patterns that can occur continuously in the rotation direction of the rotor. Means,
Compare the position information at the time of finalization determined in the current process with the position information at the time of finalization determined in the previous process, and determine whether they are the same or the signal pattern is continuous in the rotation direction of the rotor. A position information determination means at the time of confirmation,
When the change position information determining means determines that the change position information is a signal pattern continuous in the rotation direction of the rotor with respect to the fix position information determined in the previous process, and In the position information determination means, it is determined that the determined position information determined in the current process is the same as the determined position information determined in the previous process, or the signal pattern is continuous in the rotation direction of the rotor. A drive signal output means for updating a drive signal for switching a pattern for energizing the brushless motor from the inverter circuit,
Interrupt request control means for prohibiting the creation of the position information at the time of change and the position information at the time of determination for a fixed time after switching the drive signal;
A control device for a brushless motor, comprising: The brushless motor control device according to claim 1, wherein the fixed position information is position information when a plurality of pieces of position information acquired at different times coincide with each other.

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