JP5995066B2 - Control device for two-phase brushless motor - Google Patents

Description

  The present invention relates to a control device for a two-phase brushless motor that estimates a rotor position based on an induced voltage and drives a two-phase brushless motor using the estimated rotor position.

  The two-phase brushless motor includes a rotor having a magnet having at least one pair of magnetic pole pairs, and a stator having a field coil connected in two phases. A conventional control device for a two-phase brushless motor includes a Hall element for detecting a rotor position and a drive circuit for supplying drive currents having different phases to each field coil based on an output signal of the Hall element.

JP 2000-165480 A

The conventional control device for the two-phase brushless motor described above has a problem that it is difficult to reduce the size and cost of the two-phase brushless motor because a Hall element and wiring accompanying it are necessary.
Therefore, the present applicant has devised a sensorless motor control device that drives a two-phase brushless motor without using a sensor for detecting the rotor position such as a Hall element. The motor control device devised by the present applicant has a drive circuit for supplying power to two field coils connected in two phases, and an induced voltage that appears by simultaneously shutting off the energization of the two field coils. A detection circuit for detecting the zero cross point and a control circuit for controlling the drive circuit based on the zero cross point detected by the detection circuit are included.

In the motor control device devised by the present applicant, in the electrical angle region including the zero cross point of the induced voltage generated in the field coil, it is necessary to cut off the energization to the two field coils. The drive voltage cannot be applied in the electrical angle region including the zero cross point of the induced voltage generated in the coil.
An object of the present invention is to provide a driving device for a two-phase brushless motor that can apply a driving voltage in an electrical angle region including a time point when an induced voltage generated in a field coil passes a reference voltage. .

The invention according to claim 1 is a two-phase brushless comprising a stator having a first phase field coil (3) and a second phase field coil (4), and a rotor facing the stator. A control device for the motor (2), which is provided in the stator separately from the first-phase and second-phase field coils, and is generated in the first-phase field coil by the rotation of the rotor An induced voltage detection coil (5, 6) for generating an induced voltage having a phase different from that of the voltage and the induced voltage generated in the second phase field coil; the first phase field coil; and the second phase. And a drive circuit (12) for supplying drive currents having different phases to the field coil and a reference voltage passage time point at which the induced voltage generated in the induced voltage detection coil passes a predetermined reference voltage. Means for detecting the reference voltage passage time ( And 3,14), said reference voltage passing through time-out based on the reference voltage pass time, which is detected by the detection means, control means for controlling the drive circuit without using a sensor for detecting the rotation angle of the rotor ( 14) and a control device for a two-phase brushless motor. In addition, although the alphanumeric character in parentheses represents a corresponding component in an embodiment described later, of course, the scope of the present invention is not limited to the embodiment. The same applies hereinafter.

  According to the present invention, it is possible to control a drive circuit for supplying drive currents having different phases to these field coils without detecting induced voltages generated in the first and second phase field coils. It becomes possible. For this reason, in the electrical angle region including the time when the induced voltage generated in the field coils of the first phase and the second phase passes the reference voltage (the median value between the maximum value and the minimum value of the induced voltage waveform). Also, it becomes possible to apply a driving voltage.

This makes it possible to apply a drive voltage to the first-phase and second-phase field coils in almost all regions of the electrical angle. In addition, since it is possible to freely set the phase between the induced voltage generated in the field coils of the first phase and the second phase and the drive voltage applied to them, for example, advance angle control can be performed. It becomes .

In one embodiment of the present invention, the second phase field coil is disposed at a position that is 180 degrees out of phase with respect to the first phase field coil. The coil is disposed at a position that is 90 degrees out of phase with respect to the first phase field coil, and the drive circuit is configured to turn on / off the first and second phase field coils. A plurality of switching elements (SW1 to SW4) for switching the energization pattern are included. The control means applies the reference voltage passage time to the first phase and second phase field coils based on the time interval (T) of the reference voltage passage time detected by the reference voltage passage time detection means. Setting means (14) for setting a first time until the energization is stopped and a second time until the energization of the first and second phase field coils is started from a reference voltage passing time; Reference voltage passage time detected by the reference voltage passage time detection means, the first time and the second time set by the setting means, and information for specifying an energization pattern for starting energization And a means (14) for controlling the plurality of switching elements.

FIG. 1 is an electric circuit diagram showing a schematic configuration of a control device for a two-phase brushless motor according to an embodiment of the present invention. FIG. 2 is an electric circuit diagram showing the configuration of the comparison circuit. FIG. 3 shows that the α-phase field coil, β-phase field coil, γ-phase induced voltage detection coil and δ-phase induced voltage detection coil are generated when the rotor of the two-phase brushless motor rotates in a predetermined direction. It is a time chart which shows the induced voltage waveform to do. FIG. 4 is a time chart showing a control example of the switching element. FIG. 5 is a flowchart showing a procedure of processing executed by the control circuit in order to perform control as shown in FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is an electric circuit diagram showing a schematic configuration of a control device for a two-phase brushless motor according to an embodiment of the present invention.
The control device 1 for the two-phase brushless motor 2 includes a rectifier circuit 11, a drive circuit 12, a comparison circuit 13, and a control circuit 14. The two-phase brushless motor 2 is used as a motor for driving an electric pump, for example.

  The two-phase brushless motor 2 includes a rotor (not shown) having a pair of magnetic poles, an α-phase field coil 3, a β-phase field coil 4, a γ-phase induced voltage detection coil 5, and a δ-phase induced voltage detection coil. 6 (not shown). The β phase field coil 4 is arranged at a position that is 180 degrees out of phase with respect to the α phase field coil 3. The α-phase field coil 3 and the β-phase field coil 4 are connected in series.

  The γ-phase induced voltage detection coil 5 is disposed at a position that is 90 degrees out of phase with the α-phase field coil 3. The δ-phase induced voltage detection coil 6 is arranged at a position that is 180 degrees out of phase with the γ-phase induced voltage detection coil 5. The γ-phase induced voltage detection coil 5 and the δ-phase induced voltage detection coil 6 are connected in series. Note that the γ-phase induced voltage detection coil 5 and the δ-phase induced voltage detection coil 6 may not be electrically connected.

The rectifier circuit 11 rectifies the alternating current output from the alternating current power supply 10 to create a direct current power supply.
The drive circuit 12 supplies drive currents having different phases to the α-phase field coil 3 and the β-phase field coil 4. The drive circuit 12 includes four switching elements (first to fourth switching elements SW1 to SW4) for energizing / interrupting the field coils 3 and 4 and switching the energization pattern. As the switching elements SW1 to SW4, for example, a field effect transistor (FET), an insulated gate bipolar transistor (IGBT), or the like is used.

  In this embodiment, the drive circuit 12 is composed of an H bridge circuit. The drive circuit 12 includes a series circuit of a pair of switching elements SW1 and SW2 corresponding to the α phase of the two-phase brushless motor 2, and a series circuit of a pair of switching elements SW3 and SW4 corresponding to the β phase of the two-phase brushless motor 2. Are connected in parallel to the rectifier circuit 14. The α-phase field coil 3 of the two-phase brushless motor 2 is connected to a connection point between a pair of switching elements SW1 and SW2 corresponding to the α-phase. The β-phase field coil 4 of the two-phase brushless motor 2 is connected to a connection point between a pair of switching elements SW3 and SW4 corresponding to the β phase.

A direction in which the current I _α flows from one end connected to the α-phase field coil 3 to the connection point with the β-phase field coil 4 from one end connected to the drive circuit 12 is defined as an α + direction, and the opposite direction is defined as α−. Defined as direction. Further, the direction in which the current I _β flows from the one end connected to the drive circuit 12 to the connection point with the α-phase field coil 3 is defined as the β + direction, and the opposite direction is defined as the β-phase field coil 4. The β-direction is defined.

  The energization pattern includes a first energization pattern in which current flows from the α-phase field coil 3 side toward the β-phase field coil 4 side, and from the β-phase field coil 4 side toward the α-phase field coil 3 side. There is a second energization pattern through which current flows. The first energization pattern is realized by turning on the first and fourth switching elements SW1 and SW4. On the other hand, the second energization pattern is realized by turning on the second and third switching elements SW2 and SW3.

The γ-phase induced voltage detection coil 5 and the δ-phase induced voltage detection coil 6 are not connected to the drive circuit 12. When the rotor of the two-phase brushless motor 2 is rotating, an induced voltage is generated in the α-phase field coil 3, the β-phase field coil 4, the γ-phase induced voltage detection coil 5 and the phase-induced voltage detection coil 6. .
The comparison circuit 13 receives a γ-phase induced voltage V _γ generated in the γ-phase induced voltage detection coil 5 and a δ-phase induced voltage V _δ generated in the δ-phase induced voltage detection coil 6. As shown in FIG. 2, the comparison circuit 13 includes a first operational amplifier 21 for detecting a reference voltage passage time point at which the γ-phase induced voltage V _γ passes a predetermined first reference voltage, and a δ-phase induced voltage. And a second operational amplifier 22 for detecting a reference voltage passage time at which V _δ passes a predetermined second reference voltage.

The “first reference voltage” is set to a median value between the maximum value and the minimum value of the γ-phase induced voltage V _γ , and the “second reference voltage” is the maximum value of the δ-phase induced voltage V _δ Set to the median between the minimum values. In this embodiment, for convenience of explanation, it is assumed that the first reference voltage and the second reference voltage are 0 [V]. A reference voltage passing time point at which the γ-phase induced voltage V _γ passes the first reference voltage is referred to as a “zero cross point”. Similarly, a reference voltage passage time point at which the δ-phase induced voltage V _δ passes the second reference voltage is referred to as a “zero cross point”.

A γ-phase induced voltage V _γ is input to the non-inverting input terminal of the first operational amplifier 21. The inverting input terminal of the first operational amplifier 21 receives a reference voltage (0 V in this embodiment) for detecting a reference voltage passing time (zero cross point in this embodiment) of the γ-phase induced voltage V _γ. . The output signal γ _OUT of the first operational amplifier 21 becomes H level when the γ-phase induced voltage V _γ is larger than the reference voltage, and becomes L level when the γ-phase induced voltage V _γ is equal to or lower than the reference voltage. The output signal γ _OUT of the first operational amplifier 21 is given to the control circuit 14.

A δ-phase induced voltage V _δ is input to the non-inverting input terminal of the second operational amplifier 22. The inverting input terminal of the second operational amplifier 22 receives a reference voltage (0 V in this embodiment) for detecting the reference voltage passing time (zero cross point in this embodiment) of the δ-phase induced voltage V _δ. . The output signal δ _OUT of the second operational amplifier 22 is at the H level when the δ phase induced voltage V _δ is greater than the reference voltage, and is at the L level when the δ phase induced voltage V _δ is less than or equal to the reference voltage. The output signal δ _OUT of the second operational amplifier 22 is given to the control circuit 14.

The control circuit 14 can detect the zero-cross point of the γ-phase induced voltage V _γ by monitoring the time point when the output signal γ _{OUT of} the first operational amplifier 21 changes. Similarly, the control circuit 14 can detect the zero cross point of the δ-phase induced voltage V _δ by monitoring the time when the output signal δ _{OUT of} the second operational amplifier 22 changes. Since the phase difference between the γ-phase induced voltage V _γ and the δ-phase induced voltage V _δ is 180 degrees, the zero-cross point of the γ-phase induced voltage V _{γ and} the zero-cross point of the δ-phase induced voltage V _δ are almost the same time. .

The control circuit 14 performs on / off control of each switching element SW1 to SW4 in the drive circuit 12 based on at least one of the zero cross point of the γ phase induced voltage V _{γ and} the zero cross point of the δ phase induced voltage V _δ . In this embodiment, the control circuit 14 based on the zero crossing points of the gamma phase induced voltage V _gamma, it is assumed that off controls the switching elements SW1~SW4 in the drive circuit 12. The control circuit 14 includes a microcomputer having a CPU and a memory (ROM, RAM, etc.).

FIG. 3 shows an α-phase field coil 3, a β-phase field coil 4, a γ-phase induced voltage detection coil 5 and a δ-phase induced voltage detection when the rotor of the two-phase brushless motor 2 is rotating in a predetermined direction. 6 is a time chart showing a waveform of an induced voltage generated in the coil 6 for use.
In FIG. 3, V _α represents an α-phase induced voltage generated in the α-phase field coil 3, and V _β represents a β-phase induced voltage generated in the β-phase field coil 4. V _γ represents a γ-phase induced voltage generated in the γ-phase induced voltage detection coil 5, and V _δ represents a δ-phase induced voltage generated in the δ-phase induced voltage detection coil 6.

In the example of FIG. 3, the electrical angle when the α-phase induced voltage V _α crosses the reference voltage (in this example, 0 [V]) from the minus side to the plus side is set to 0 degree. For convenience of explanation, the horizontal axis in FIG. 3 does not represent the electrical angle, but represents the rotation amount (mechanical angle) of the rotor from a predetermined reference position where the electrical angle is 0 degrees.
The phases of the α-phase induced voltage V _α , the δ-phase induced voltage V _δ , the β-phase induced voltage V _β and the γ-phase induced voltage V _γ are shifted by 90 degrees. Specifically, the phase of the δ phase induced voltage V _δ is delayed by 90 degrees with respect to the α phase induced voltage V _α . The phase of the β-phase induced voltage _Vβ is delayed by 90 degrees with respect to the δ-phase induced voltage _Vδ . The gamma phase induced voltage V _gamma, phase with respect to beta-phase induced voltage V _beta is delayed 90 degrees. In other words, the phase of the γ-phase induced voltage V _γ is advanced by 90 degrees with respect to the α-phase induced voltage V _α .

FIG. 4 is a time chart showing a control example of the switching element. In FIG. 4, Vd _α represents an α-phase drive voltage applied to the α-phase field coil 3. Vd _β represents a β-phase drive voltage applied to the β-phase field coil 4. FIG. 4 shows an operation example in the case where the advance angle control is performed with the timing of applying the drive voltage advanced with respect to the phase of the induced voltage generated in the field coils 3 and 4. When such advance angle control is performed, the rotational speed of the two-phase brushless motor 2 can be increased.

In the control example of FIG. 4, the rotation angle (electrical angle) of the rotor is within a section from about 330 degrees to about 120 degrees (a section from about 330 degrees to about 360 degrees and a section from about 0 degrees to about 120 degrees). When the angle is set, the switching elements SW1 and SW4 are turned on. That is, in this section, the α-phase field coil 3 and the β-phase field coil 4 are energized by the first energization pattern P1. As a result, a positive α-phase drive voltage Vd _α is applied to the α-phase field coil 3 and a negative β-phase drive voltage Vd _β is applied to the β-phase field coil 4.

When the rotation angle (electrical angle) of the rotor is an angle in a section from about 150 degrees to about 300 degrees, the switching elements SW2 and SW3 are turned on. That is, in this section, the α-phase field coil 3 and the β-phase field coil 4 are energized by the second energization pattern P2. As a result, a negative α-phase drive voltage Vd _α is applied to the α-phase field coil 3 and a positive β-phase drive voltage Vd _β is applied to the β-phase field coil 4. When the rotation angle (electrical angle) of the rotor is an angle within a section of about 120 degrees to about 150 degrees or an angle within a section of about 300 degrees to about 330 degrees, all the switching elements SW1 to SW4 are in an off state. To be.

FIG. 5 is a flowchart showing a procedure of processing executed by the control circuit 14 in order to perform control as shown in FIG.
The control circuit 14 includes a first timer and a second timer (both not shown). These timers may be hard timers or soft timers. In the following, P is a control variable for specifying an energization pattern when energization is started, and is a value representing the first energization pattern P1 (represented by P1) or a value representing the second energization pattern P2 (P2). Is stored).

  The process of FIG. 5 is a process performed after the two-phase brushless motor 2 is started. The starting process of the two-phase brushless motor 2 is performed by forced commutation in the same manner as the 120-degree conduction rectangular wave sensorless drive of the three-phase brushless motor. That is, the drive voltage corresponding to the first energization pattern P1 and the drive voltage corresponding to the second energization pattern P2 are alternately and repeatedly applied to the motor 2. The duration of each energization pattern P1, P2 at the time of the starting process and the time from when one energization pattern is stopped until the other energization pattern is started are set in advance. As a result, the rotor starts rotating although it is inefficient. In this starting process, the value of the control variable P is set to P1 when energization by the energization pattern P1 is started, and the value of the control variable P is set to P2 when energization by the energization pattern P2 is started.

Referring to FIG. 5, control circuit 14 determines whether or not a zero cross point of γ-phase induced voltage V _γ has been detected (step S1). If it is determined that the zero cross point of the γ-phase induced voltage V _γ has been detected (step S1: YES), the current time is stored as the zero cross point, and the time interval between the previously detected zero cross point and the current detected zero cross point. The zero cross interval T is calculated (step S2). This zero cross interval T corresponds to the time required for the rotor of the two-phase brushless motor 2 to rotate about 180 degrees (electrical angle).

Next, the control circuit 14 on the basis of the zero crossing interval T, the zero-crossing point of the detected gamma phase induced voltage V _gamma in step S1, to turn off the two switching elements of the current on-state time (hereinafter, (Referred to as “OFF time”) is set in the first timer (step S3). Thereby, the timing of the OFF time by the first timer is started. In order to perform control as shown in FIG. 4, the OFF time is set to a time corresponding to about 30 degrees of the electrical angle. If the zero-crossing interval calculated in step S2 is T, the OFF time is set to T / 6.

Further, the control circuit 14 on the basis of the zero crossing interval T, from the zero-cross point of the detected gamma phase induced voltage V _gamma in step S1, until turning on two switching elements corresponding to the next energization pattern time ( The time until the next energization is started (hereinafter referred to as “ON time”) is set in the second timer (step S4). Thereby, the time measurement of the ON time by the second timer is started. In order to perform control as shown in FIG. 4, the ON time is set to a time corresponding to about 60 degrees of electrical angle. When the zero-crossing interval calculated in step S2 is T, the ON time is set to T / 3.

Thereafter, the control circuit 14 determines whether or not the value of the control variable P is a value P1 representing the first energization pattern P1 (step S5). When the zero cross point of the γ-phase induced voltage V _γ is detected, the control variable P stores a value corresponding to the energization pattern (current energization pattern) at that time. That is, when the zero-cross point of the γ-phase induced voltage V _γ is detected, if the value of the control variable P is P1, it indicates that the first energization pattern P1 is energized at that time, When the value of the control variable P is P2, it indicates that energization by the second energization pattern P2 is being performed at that time.

In step S5, when the value of the control variable P is P1 (step S5: YES), the control circuit 14 changes the value of the control variable P to a value P2 representing the second energization pattern P2 (step S6). . Thereby, the value of the control variable P becomes a value indicating the next energization pattern. Then, the process returns to step S1.
In step S5, when the value of the control variable P is P2 (step S5: NO), the control circuit 14 changes the value of the control variable P to a value P1 representing the first energization pattern P1 (step S7). . Thereby, the value of the control variable P becomes a value indicating the next energization pattern. Then, the process returns to step S1.

In step S1, if it is determined that not detected zero crossing points of the gamma phase induced voltage V _gamma (step S1: NO), the control circuit 14, the value of the control variable P is the first energization pattern P1 It is determined whether or not the value P1 is represented (step S8).
If the value of the control variable P is P1 (step S8: YES), the control circuit 14 determines whether or not the OFF time has elapsed since the start of the OFF time in step S3 (step S3). Step S9). In this step S9, only when the time measurement of the OFF time by the first timer is not completed in the previous step S9 and the time measurement of the OFF time by the first timer is completed in this step S9, the control circuit 14 Determines that the OFF time has elapsed. Therefore, even if the time measurement of the OFF time by the first timer is completed in step S9 this time, if the time measurement of the OFF time by the first timer is completed in the previous step S9, the control circuit 14 It is not determined that it has passed.

  If it is not determined in step S9 that the OFF time has elapsed (step S9: NO), the control circuit 14 determines whether the ON time has elapsed since the start of the ON time measurement in step S4. Is determined (step S12). In this step S12, the control circuit 14 only when the time measurement of the ON time by the second timer is not completed in the previous step S12 and the time measurement of the ON time by the second timer is completed in this step S12. Determines that the ON time has elapsed. If it is not determined in step S12 that the ON time has elapsed (step S12: NO), the process returns to step S1.

If it is determined in step S9 that the OFF time has elapsed (step S9: YES), the control circuit 14 turns off the two switching elements that are currently on (steps S10 and S11).
In this case, since it is determined in step S8 that the value of the control variable P is P1, the current energization pattern is the second energization pattern P2, and the second and third switching elements SW2 and SW3 are turned on. Yes. Therefore, the control circuit 14 turns off the second switching element SW2 (step S10) and turns off the third switching element SW3 (step S11). Thereby, the energization by the 2nd electricity supply pattern P2 stops. Then, the process proceeds to step S12.

If it is determined in step S12 that the ON time has elapsed (step S12: YES), the control circuit 14 turns on the two switching elements corresponding to the next energization pattern (steps S13 and S14).
In this case, since it is determined in step S8 that the value of the control variable P is P1, the next energization pattern is the first energization pattern P1. The two switching elements corresponding to the first energization pattern P1 are the first and fourth switching elements SW1 and SW4. Therefore, the control circuit 14 turns on the first switching element SW1 (step S13) and turns on the fourth switching element SW4 (step S14). Thereby, the energization by the 1st electricity supply pattern P1 is started. Then, the process returns to step S1.

Incidentally, the processing of step S13, S14, from after the energization of the first energization pattern P1 is started, in until the zero-crossing point of the gamma phase induced voltage V _gamma in step S1 is detected, the control variables P The value indicates a value corresponding to the current energization pattern (in this case, the first energization pattern P1). During this time, since NO is obtained in steps S9 and S12, the processes in steps S1, S8, S9, and S12 are repeated.

  If it is determined in step S8 that the value of the control variable P is P2 (step S8: NO), the control circuit 14 starts the OFF time measurement from the start of the OFF time in step S3. It is determined whether or not it has elapsed (step S15). In this step S15, only when the time measurement of the OFF time by the first timer is not completed in the previous step S15 and the time measurement of the OFF time by the first timer is completed in this step S15, the control circuit 14 Determines that the OFF time has elapsed.

  If it is not determined in step S15 that the OFF time has elapsed (step S15: NO), the control circuit 14 determines whether the ON time has elapsed since the start of the ON time measurement in step S4. Is determined (step S18). In this step S18, the control circuit 14 only when the time measurement of the ON time by the second timer is not completed in the previous step S18 and the time measurement of the ON time by the second timer is completed in this step S18. Determines that the ON time has elapsed. If it is not determined in step S18 that the ON time has elapsed (step S18: NO), the process returns to step S1.

If it is determined in step S15 that the OFF time has elapsed (step S16: YES), the control circuit 14 turns off the two switching elements that are currently on (steps S16 and S17).
In this case, since it is determined in step S8 that the value of the control variable P is P2, the current energization pattern is the first energization pattern P1, and the first and fourth switching elements SW1 and SW4 are turned on. Yes. Therefore, the control circuit 14 turns off the first switching element SW1 (step S16) and turns off the fourth switching element SW4 (step S17). Thereby, the energization by the 1st electricity supply pattern P1 stops. Then, the process proceeds to step S18.

If it is determined in step S18 that the ON time has elapsed (step S18: YES), the control circuit 14 turns on the two switching elements corresponding to the next energization pattern (steps S19 and S20).
In this case, since it is determined in step S8 that the value of the control variable P is P2, the next energization pattern is the second energization pattern P2. The two switching elements corresponding to the second energization pattern P2 are the second and third switching elements SW2 and SW3. Therefore, the control circuit 14 turns on the second switching element SW2 (step S19) and turns on the third switching element SW3 (step S20). Thereby, electricity supply by the 2nd electricity supply pattern P2 is started. Then, the process returns to step S1.

Incidentally, the processing of step S19, S20, from after the energization of the second energization pattern P2 is started, in until the zero-crossing point of the gamma phase induced voltage V _gamma in step S1 is detected, the control variables P The value indicates a value corresponding to the current energization pattern (in this case, the second energization pattern P2). During this time, since NO is obtained in steps S15 and S18, the processes in steps S1, S8, S15, and S18 are repeated.

The process of FIG. 5 will be described more specifically with reference to FIG. For example, when the zero cross point of the γ-phase induced voltage V _γ corresponding to about 270 degrees of the rotor rotation angle (mechanical angle) is detected (see step S1), the γ-phase induced voltage V _γ detected one time before that is detected. A zero-cross interval T, which is a time interval from the zero-cross point (corresponding to 90 degrees of the rotor rotation angle (mechanical angle)), is calculated (see step S2).

  A time corresponding to T / 6 is set as the OFF time in the first timer (see step S3), and a time corresponding to T / 3 is set as the ON time in the second timer (see step S4). Then, the value of the control variable P is determined (see step S5). The value of the control variable P at this time is a value corresponding to the energization pattern at that time. When the rotor rotation angle (mechanical angle) is about 270 degrees, P2 is set as the value of the control variable P. Therefore, the value of the control variable P is changed to P1 indicating the next energization pattern (see step S7). Then, the process returns to step S1.

  In step S1, it is determined as NO, and the process proceeds to step S8. In step S8, it is determined YES. Therefore, the processes of steps S8, S9, S12, and S1 are repeated. Then, when the OFF time has elapsed since the start of counting of the OFF time in Step S3, YES is determined in Step S9, and the second and third switching elements SW2 and SW3 are turned off (Steps S10 and 11). reference). That is, referring to FIG. 4, when the rotor rotation angle (mechanical angle) reaches about 300 degrees, the energization by the second energization pattern P2 is stopped.

  Thereafter, the processes of steps S8, S9, S12, and S1 are repeated again. Then, when the ON time has elapsed after the start of the ON time measurement in Step S4, YES is determined in Step S12, and the first and fourth switching elements SW1 and SW4 are turned on (Steps S13 and S14). reference). That is, referring to FIG. 4, when the rotor rotation angle (mechanical angle) reaches about 330 degrees, energization by the first energization pattern P1 is started. And it returns to step S1 and the process of step S8, S9, S12, S1 is performed repeatedly.

Thereafter, when the rotor rotation angle (mechanical angle) becomes approximately 450 degrees and the zero cross point of the γ-phase induced voltage V _γ is detected (see step S1), the zero cross interval T is calculated (see step S2). A time corresponding to T / 6 is set as the OFF time in the first timer (see step S3), and a time corresponding to T / 3 is set as the ON time in the second timer (see step S4).

  Then, the value of the control variable P is determined (see step S5). The value of the control variable P at this time is a value corresponding to the energization pattern at that time. When the rotor rotation angle (mechanical angle) is about 450 degrees, P1 is set as the value of the control variable P. Therefore, the value of the control variable P is changed to P2 indicating the next energization pattern (see step S6). Then, the process returns to step S1.

  In step S1, it is determined as NO, and the process proceeds to step S8. In step S8, it is determined NO. Therefore, the processes of steps S8, S15, S18, and S1 are repeated. Then, when the OFF time has elapsed since the start of the OFF time measurement in Step S3, YES is determined in Step S15, and the first and fourth switching elements SW1 and SW4 are turned OFF (Steps S16 and 17). reference). That is, referring to FIG. 4, when the rotor rotation angle (mechanical angle) reaches about 480 degrees, the energization by the first energization pattern P1 is stopped.

  Thereafter, the processes of steps S8, S15, S18, and S1 are repeated again. Then, when the ON time has elapsed since the start of the ON time measurement in Step S4, YES is determined in Step S18, and the second and third switching elements SW2 and SW3 are turned on (Steps S20 and 21). reference). That is, referring to FIG. 4, when the rotor rotation angle (mechanical angle) reaches about 510 degrees, energization by the second energization pattern P2 is started. And it returns to step S1 and the process of step S8, S15, S18, S1 is performed repeatedly.

Thereafter, when the rotor rotation angle (mechanical angle) becomes about 630 degrees and the zero cross point of the γ-phase induced voltage V _γ is detected (see step S1), the zero cross interval T is calculated (see step S2). Thereafter, similar processing is repeatedly executed.
In this embodiment, in addition to the two-phase field coils (α-phase field coil 3 and β-phase field coil 4) for generating a rotating magnetic field, an induced voltage detection coil (γ-phase induced voltage detection coil) is used. 5 or 6-phase induced voltage detection coil 6) is provided. Then, the zero cross point of the induced voltage generated in at least one of the γ-phase induced voltage detection coil 5 and the δ-phase induced voltage detection coil 6 is detected, and the α-phase field coil 3 and the Energization to the β phase field coil 4 is controlled.

That is, the energization to the α phase field coil 3 and the β phase field coil 4 is controlled without detecting the zero cross point of the induced voltage generated in the α phase field coil 3 or the β phase field coil 4. Yes. For this reason, it is possible to apply the drive voltage even in the electrical angle region including the zero cross point of the induced voltage generated in the α-phase field coil 3 and the β-phase field coil 4.
This makes it possible to apply a drive voltage to the α-phase field coil 3 and the β-phase field coil 4 in almost all regions of the electrical angle. In addition, since the phases of the induced voltage generated in the α-phase field coil 3 and the β-phase field coil 4 and the drive voltage applied to them can be freely set, as in the above-described embodiment. Lead angle control can be performed.

As mentioned above, although one Embodiment of this invention was described, this invention can also be implemented with another form. For example, in the above embodiment, the control circuit 14 based on the zero crossing points of the gamma phase induced voltage V _gamma, although off controls the switching elements SW1~SW4 in driving circuit 12, [delta] phase induced voltage V _[delta] The switching elements SW1 to SW4 may be on / off controlled based on the zero cross point.

In the embodiment, the time corresponding to T / 6 is set as the OFF time, and the time corresponding to T / 3 is set as the ON time. However, the OFF time and the ON time are set to other values. You can also
In the control example of FIG. 4, the first voltage is applied so that the induced voltage is applied to the field coils 3 and 4 at the zero cross point of the γ-phase induced voltage V _γ (or δ-phase induced voltage V _δ ). Although the second energization pattern is set, no induced voltage is applied to the field coils 3 and 4 at the zero cross point of the γ-phase induced voltage V _γ (or δ-phase induced voltage V _δ ). Moreover, the 1st and 2nd electricity supply pattern may be set. In such a case, when the zero cross point of the γ-phase induced voltage V _γ (or δ-phase induced voltage V _δ ) is detected, the control circuit 14 determines the time from the zero cross point until the next energization is started. The second timer may be set as the ON time, and the time from the zero cross point to the end of the next energization may be set as the OFF time in the first timer. In this case, when the ON time has elapsed, the two switching elements corresponding to the next energization pattern are turned on, and when the OFF time has elapsed, the two switching elements that are in the ON state at that time are turned off. You can do it.

  In addition, various design changes can be made within the scope of matters described in the claims.

  DESCRIPTION OF SYMBOLS 1 ... Control apparatus, 2 ... Two phase brushless motor, 3 ... (alpha) phase field coil, 4 ... (beta) phase field coil, 5 ... (gamma) phase induced voltage detection coil, 6 ... (delta) phase induced voltage detection coil, 12 ... Drive circuit, 13... Comparison circuit, 14... Control circuit, 21, 22... Operational amplifier, SW1 to SW4.

Claims (2)

A control device for a two-phase brushless motor comprising a stator having a first phase field coil and a second phase field coil, and a rotor facing the stator,
In addition to the first phase and second phase field coils, the stator is provided in the stator, and an induced voltage generated in the first phase field coil and the second phase field coil by rotation of the rotor. An induced voltage detecting coil that generates an induced voltage having a phase different from that of the induced voltage ;
A drive circuit for supplying drive currents having different phases to the first phase field coil and the second phase field coil;
A reference voltage passage time detection means for detecting a reference voltage passage time, which is a time when an induced voltage generated in the induced voltage detection coil passes a predetermined reference voltage;
-Out based on the reference voltage pass time, which is detected by the reference voltage pass time detecting means, and a control means for controlling the drive circuit without using a sensor for detecting the rotation angle of the rotor, two-phase brushless Motor control device. The second phase field coil is disposed at a position 180 degrees out of phase with respect to the first phase field coil .
The induced voltage detection coil is disposed at a position 90 degrees out of phase with respect to the first phase field coil.
The drive circuit includes a plurality of switching elements for energizing / interrupting the first and second phase field coils and switching an energization pattern;
The control means includes
Based on the time interval between the reference voltage passage times detected by the reference voltage passage time detection means, a first time from when the reference voltage passage time until the energization to the first phase and second phase field coils is stopped; Setting means for setting a second time from when a reference voltage passes through until the first and second phase field coils start energization;
Information for specifying a reference voltage passage time detected by the reference voltage passage time detection means, the first time and the second time set by the setting means, and an energization pattern for starting energization; 2. The control device for a two-phase brushless motor according to claim 1, further comprising: means for controlling the plurality of switching elements based on

Images