JP4583109B2 - Sensorless motor drive device - Google Patents

Description

  The present invention relates to a sensorless motor driving apparatus.

A sensorless motor (for example, a three-phase brushless motor) does not have a relative position detection element of the rotor with respect to the stator. Therefore, the drive circuit that energizes the motor coil of the sensorless motor first energizes a predetermined phase of the motor coil, and detects the stop position of the rotor based on the zero cross caused by the rise or fall of the counter electromotive force generated in the motor coil. Thereafter, each phase of the motor coil can be appropriately energized by the starting logic corresponding to the rotor stop position. As a result, the sensorless motor rotates. (For example, see Patent Document 1)
A sensorless motor using a multiplier circuit is also known for controlling the conduction of a motor coil. The multiplier circuit generates a rectangular signal of n periods (for example, 16 periods) in a half period of the combined signal RE2 whose period changes according to the rotation speed of the motor, and is output from the multiplier circuit. The rectangular signal is a signal proportional to the rotational speed of the motor. The drive circuit controls energization of the motor coil by performing logical processing using the rectangular signal output from the multiplier circuit. The composite signal RE2 is a signal obtained based on the zero cross of the coil voltage.

Thus, the conventional sensorless motor drive device controls the energization of the motor coil by using the multiplier circuit.
JP 2001-275389 A

  The above-described multiplication circuit outputs a rectangular signal obtained by multiplying a period of 1/2 cycle of the immediately preceding combined signal RE2 to 16 periods by a 1/2 period of the combined signal RE2. At this time, when the half cycle (referred to as A period) of the immediately preceding composite signal RE2 is, for example, half of the 1/2 cycle (referred to as B period) of the next composite signal RE2, the multiplier circuit A rectangular signal having 16 periods is generated in the B period. Therefore, the rectangular signal generated in the multiplier circuit in the B period is 32 cycles. Thus, when the half cycle of the composite signal RE2 is not accurate, the rectangular signal for controlling the conduction of the motor coil is also not accurate. Therefore, it is necessary that the combined signal RE2 is a signal in which each ½ cycle changes at an accurate timing.

  However, at the time of starting the sensorless motor, there is a possibility that the zero point of the accurate timing may not be obtained at the changing point of the composite signal RE2 after the rotation of the rotor is detected (rise and fall of the composite signal RE2). That is, there is a possibility that the half cycle of the composite signal RE2 is not accurate. At this time, the rectangular signal output from the multiplier circuit is not an accurate signal. Therefore, in a drive device using a multiplier circuit, when the motor is started, the rotation of the motor and the control timing of the drive circuit do not match, and the start of the motor may become unstable.

As described above, the conventional sensorless motor driving apparatus has a problem that when the motor is started, the motor start becomes unstable because the half cycle of the composite signal RE2 is not accurate.
SUMMARY OF THE INVENTION An object of the present invention is to provide a sensorless motor driving apparatus that can stably start a motor when the motor is started.

In principal the invention, the drive device selectively energized to Rousset Nsaresumota the motor coil based on the counter electromotive voltage generated in the motor coil of a plurality of phases for solving the above problem, a coil of the motor coil of the plurality of phases A plurality of comparators for comparing a voltage and a neutral point voltage and outputting a plurality of comparison signals; and a mask circuit for outputting a plurality of mask signals obtained by removing noise corresponding to kickback pulses from the plurality of comparison signals; A sensorless logic circuit that outputs a signal for selectively energizing the motor coil based on the plurality of mask signals, a start-up oscillation circuit that generates a first rectangular signal having a fixed period, and the plurality of mask signals are combined. and a synthesizing circuit for generating a second rectangular signal which changes periodically in accordance with the rotational speed of the sensorless motor, each of said second rectangular signal 1 / A multiplication circuit for generating a third rectangular signal for multiplying a half period immediately before the half period into a plurality of predetermined periods, and an output of one of the start-up oscillation circuit and the multiplication circuit Switching circuit to be supplied to the mask circuit as a signal for removing the noise, and whether the third rectangular signal generated in the half period of the second rectangular signal is the plurality of periods comprising a determining circuit for determining whether the said determination circuit, when the third rectangular signal generated in the period of the half cycle of the second rectangular signal is first determined if there in the plurality of cycles The switching circuit is switched from the start-up oscillation circuit side to the multiplication circuit side after the 1/2 cycle based on the determination result of

The comparison apparatus for driving a selectively energized to Rousset Nsaresumota the motor coil based on the counter electromotive voltage generated in the motor coil of a plurality of phases, the coil voltage and the neutral point voltage of the motor coil of the plurality of phases A plurality of comparators that output a plurality of comparison signals; a mask circuit that outputs a plurality of mask signals obtained by removing noise corresponding to kickback pulses from the plurality of comparison signals; and the plurality of mask signals based on the plurality of mask signals. A sensorless logic circuit that outputs a signal for selectively energizing the motor coil; a rotor rotation detection circuit that detects rotation of the rotor; a start-up oscillation circuit that generates a first rectangular signal having a constant period; and the plurality of masks and combining the signals, and a synthesizing circuit for generating a second rectangular signal which changes periodically in accordance with the rotational speed of the sensorless motor, wherein the second rectangular A multiplier circuit for generating a third rectangular signal for multiplying a ½ cycle immediately before the ½ cycle to a plurality of predetermined cycles, and the start-up oscillation circuit and the multiplier circuit A switching circuit that switches the output of any one of the signals to be supplied to the mask circuit as a signal for removing the noise, and the level of the second rectangular signal changes a predetermined number of times after the rotation of the rotor is detected. A determination circuit for determining whether the level of the second rectangular signal has changed a predetermined number of times after the rotation of the rotor has been detected. On the basis of the switching circuit, the switching circuit is switched from the start-up oscillation circuit side to the multiplication circuit side after the predetermined number of change points. It becomes more apparent.

  According to the present invention, after the third rectangular signal generated in the period of ½ period of the second rectangular signal whose period changes according to the rotation speed of the motor becomes a plurality of predetermined periods, it is constant after Since the motor coil is energized by switching from the output side of the start oscillation circuit of the cycle to the output side of the multiplier circuit, the sensorless motor can be stably started.

  Further, by counting the change in the level of the second rectangular signal whose cycle changes according to the rotation speed of the motor after the rotation of the rotor is detected, the output side of the multiplier circuit is changed from the output side of the start-up oscillation circuit of the switching circuit. Switching to can be performed easily.

  At least the following matters will become apparent from the description of this specification and the accompanying drawings.

=== Configuration of Sensorless Motor Drive Device ===
A sensorless motor driving apparatus according to the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a circuit block diagram for explaining a sensorless motor driving apparatus according to the present invention. FIG. 2 is a waveform diagram for explaining a sensorless motor driving apparatus according to the present invention. In the present embodiment, the driving device drives, for example, a three-phase DC brushless motor as the sensorless motor.

  The U-phase coil 2, the V-phase coil 4, and the W-phase coil 6 are motor coils, and are wound around the stator with a star connection and a phase difference of 120 electrical degrees.

  The N-channel MOSFET 8 is a source transistor for supplying a coil current from the power source VP to the U-phase coil 2, and the N-channel MOSFET 10 is a sink transistor for supplying a coil current from the U-phase coil 2 to the ground VSS. is there. The drain / source paths of the MOSFETs 8 and 10 are connected in series between the power source VP and the ground VSS, and the drain / source connection portions of the MOSFETs 8 and 10 are connected to one end of the U-phase coil 2. The N-channel MOSFET 12 is a source transistor for supplying a coil current from the power source VP to the V-phase coil 4, and the N-channel MOSFET 14 is a sink transistor for supplying a coil current from the V-phase coil 4 to the ground VSS. is there. The drain / source paths of the MOSFETs 12 and 14 are connected in series between the power supply VP and the ground VSS, and the drain / source connection portions of the MOSFETs 12 and 14 are connected to one end of the V-phase coil 4. The N-channel MOSFET 16 is a source transistor for supplying a coil current from the power source VP to the W-phase coil 6, and the N-channel MOSFET 18 is a sink transistor for supplying a coil current from the W-phase coil 6 to the ground VSS. is there. The drain / source paths of these MOSFETs 16 and 18 are connected in series between the power supply VP and the ground VSS, and the drain / source connection portions of these MOSFETs 16 and 18 are connected to one end of the W-phase coil 6. Then, when the MOSFETs 8, 10, 12, 14, 16, 18 are turned on and off at appropriate timing, the motor is supplied with coil currents to the U-phase coil 2, the V-phase coil 4, and the W-phase coil 6 in a predetermined direction. (For example, forward rotation). As a result, coil voltages VU, VV, and VW having a phase difference of 120 electrical degrees are generated at one end of the U-phase coil 2, the V-phase coil 4, and the W-phase coil 6. Note that, as the source transistor and the sink transistor, not only MOSFETs but also bipolar transistors can be used.

  The comparator 22U is applied with the coil voltage VU applied to the + terminal and the neutral point voltage VCOM applied to the − terminal, and changes at the timing of an electrical angle of 180 degrees by comparing the coil voltage VU and the neutral point voltage VCOM. The rectangular comparison signal CPU is output. A pulse based on the kickback pulse KB is superimposed on the comparison signal CPU. In addition, the comparator 22V receives the coil voltage VV applied to the + terminal and the neutral point voltage VCOM applied to the − terminal, and compares the coil voltage VV and the neutral point voltage VCOM so that the timing of the electrical angle is 180 degrees. The rectangular comparison signal CPV that changes in the above is output. A pulse based on the kickback pulse KB is superimposed on the comparison signal CPV. Further, the comparator 22W receives the coil voltage VW at the + terminal and the neutral point voltage VCOM at the − terminal, and compares the coil voltage VW with the neutral point voltage VCOM to thereby obtain a timing of an electrical angle of 180 degrees. A rectangular comparison signal CPW that changes at A pulse based on the kickback pulse KB is superimposed on the comparison signal CPW. The comparison signals CPU, CPV, and CPW each have a phase difference of 120 electrical degrees.

  The mask circuit 26 removes (masks) noise corresponding to the kickback pulse KB from the comparison signal CPU, which is the output of the comparator 22U, based on the output of the switching circuit 36, and generates and outputs a mask signal UMASK. The mask circuit 26 removes (masks) noise corresponding to the kickback pulse KB based on the output of the switching circuit 36 from the comparison signal CPV that is the output of the comparator 22V, and generates and outputs a mask signal VMASK. Further, the mask circuit 26 removes (masks) noise corresponding to the kickback pulse KB based on the output of the switching circuit 36 from the comparison signal CPW that is the output of the comparator 22W, and generates and outputs a mask signal WMASK. Here, the mask signals UMASK, VMASK, and WMASK have a phase difference of an electrical angle of 120 degrees. Note that the mask circuit 26 performs noise processing corresponding to the kickback pulse KB by performing logical processing using a rectangular signal RE1 supplied from a multiplier circuit 30 described later or a startup oscillation signal supplied from the startup oscillation circuit 32. Remove.

  The synthesizing circuit 28 synthesizes the mask signals UMASK, VMASK, and WMASK output from the mask circuit 26, and outputs a rectangular synthesized signal RE2 that changes at a timing of an electrical angle of 60 degrees.

  The multiplier circuit 30 multiplies the composite signal RE2 output from the composite circuit 28. A rectangular signal RE1 ("third rectangular signal") having a higher frequency than the synthesized signal RE2 is generated. As a result, the phase of the combined signal RE2 matches the phase of the rectangular signal RE1, and the 1/2 cycle of the combined signal RE2 matches the n cycle of the rectangular signal RE1, for example, 16 cycles. For example, a PLL (Phase Locked Loop) that performs analog signal processing and a DLL (Delay Locked Loop) that performs digital signal processing can be applied to the multiplication circuit 30. In the present embodiment, the multiplier circuit 30 applies the latter DLL.

  The start-up oscillation circuit 32 outputs only a start-up oscillation signal (“first rectangular signal”) for starting the motor that oscillates at a constant cycle, using only the oscillation circuit. The startup oscillation signal output from the startup oscillation circuit 32 is a signal having the lowest frequency among the frequency division frequencies of the PLL circuit obtained when the motor is stopped.

  The startup / normal control selection circuit 34 (“discrimination circuit”) determines the timing for switching the switching circuit 36 based on the composite signal RE2 and the rectangular signal RE1, and multiplies the switching circuit 36 from the startup oscillation circuit 32 side based on the determination result. Switch to the circuit 30 side.

  The switching circuit 36 selects and outputs either the output of the multiplication circuit 30 or the activation transmission circuit 32 according to the output of the activation / normal control selection circuit 34.

  The startup counter 38 counts the startup oscillation signal output from the startup oscillation circuit 32 on the basis of the unit of the electrical angle of 60 degrees of the combined signal RE2 when the sensorless motor in the stopped state does not start. Then, when the activation counter 38 counts a predetermined value, the sensorless logic circuit 40 switches the level of the mask signals UMASK, VMASK, and WMASK to the next electrical angle of 60 degrees. When the sensorless motor is stopped, the cycle of the startup oscillation signal from the startup oscillation circuit 32 is held at a constant cycle.

  The sensorless logic circuit 40 outputs a signal for energizing the U-phase coil 2, the V-phase coil 4, and the W-phase coil 6 at an appropriate timing. In other words, the sensorless logic circuit 40 considers that the sensorless motor itself cannot determine the relative position between the rotor and the stator before starting, and when the rotor is stopped, the mask signals UMASK, VMASK, and WMASK are predetermined. It operates from the initial level (for example, UMASK = “L”, VMASK = “L”, WMASK = “H”). In addition, the sensorless logic circuit 40 generates energization signals ULOGIC1 (= UMASK-VMASK), VLOGIC1 (= VMASK-WMASK), and WLOGIC1 (= WMASK-UMASK). When the U-phase coil 2, the V-phase coil 4, and the W-phase coil 6 are energized, the sensorless logic circuit 40 outputs energization signals ULOGIC2, VLOGIC2, and WLOGIC2 that are delayed from the energization signals ULOGIC1, VLOGIC1, and WLOGIC1. Based on the ULOGIC2, VLOGIC2, and WLOGIC2, the U-phase coil 2, the V-phase coil 4, and the W-phase coil 6 are energized to drive the motor.

  The comparators 22V, 22U, and 22W constitute a rotor rotation detection circuit. The mask circuit 26 and the sensorless logic circuit 40 constitute a drive circuit.

=== Relationship between Rectangular Signal RE1 and Composite Signal RE2 ===
FIG. 3 is a diagram for explaining the relationship between the rectangular signal RE1 and the combined signal RE2.
FIG. 3A is a diagram illustrating an example of the relationship between the rectangular signal RE1 and the combined signal RE2 when the energization control of the motor coil is normal. FIG. 3B is a diagram showing an example of the relationship between the rectangular signal RE1 and the combined signal RE2 when the motor is started.

  The synthesized signal RE2 (“second rectangular signal”) is a synthesized signal obtained by synthesizing UMASK, VMASK, and WMASK in the synthesis circuit 28, and is output to the multiplication circuit 30 and the start / normal control selection circuit 34. The rising and falling changes of the composite signal RE2 coincide with the zero crossing of the coil voltages VU, VV, VW. The multiplication circuit 30 multiplies the combined signal RE2 into a rectangular signal RE1 having a period that is an integral multiple of the combined signal RE2, for example, 16 times. That is, a rectangular signal RE1 having 16 periods (16 pulses) is generated in a half period between the rising edge and the falling edge of the combined signal RE2. Therefore, when the 16-pulse rectangular signal R1 is generated in the period of ½ cycle of the combined signal RE2, it can be determined that the rotation of the motor and the energization logic of the drive circuit coincide. In the multiplier circuit 30, the immediately preceding 1/2 cycle is actually reflected in the operation of the next 1/2 cycle. Specifically, as shown in FIG. 3B, when the half period of the combined signal RE2 in the period TA is “a”, 16 periods are generated in the “a” period in the next period TB. Since the multiplying circuit 30 operates so that the rectangular signal RE1 is generated in the period TB, the rectangular signal RE1 having 16 cycles or more is generated. For example, when “a” is ½ of “b”, a rectangular signal RE1 of 32 cycles is generated in the period TB. In this case, since the cycle of the rectangular signal RE1 is not accurate, the rotation of the motor and the energization logic of the drive circuit do not match. Therefore, in the present embodiment, the case where the rectangular signal RE1 generated during the ½ period of the combined signal RE2 is 16 periods is normal, and the rectangular signal RE1 generated during the ½ period of the combined signal RE2 is normal. A case other than 16 cycles is regarded as abnormal. Note that the activation / normal control selection circuit 34 includes a counter (not shown), for example, and can determine whether or not the rectangular signal RE1 generated in the half period of the combined signal RE2 has 16 periods. I can do it.

  Note that in the multiplication circuit 30 using the DLL, normally, if the rising and falling change points of the composite signal RE2 are generated twice in succession, the multiplication operation is executed, and a rectangle having 16 cycles in that period is executed. It is possible to generate the signal RE1 with a half cycle of the next combined signal RE2. However, in actuality, there is a possibility that the first and second rising / falling change points of the first combined signal RE2 after the detection of the rotation of the rotor is not a zero crossing of the accurate timing (hereinafter, for convenience, the rotor The change point of the n-th synthesized signal RE2 after the rotation of the first rotation is detected is defined as the n-th change point).

  When the second change point of the composite signal RE2 is normal, the motor is normally driven at the change point, and “b” is an accurate period. In the period TC, a 16-cycle rectangular signal RE1 is generated. Therefore, when the second change point of the composite signal RE2 is normal, the rotation of the motor coincides with the energization logic of the drive circuit after the start point of the period TC, that is, after the third change point of the composite signal RE2. Judgment can be made.

  On the other hand, when the second change point of the composite signal RE2 is abnormal and the motor is not driven normally at the second change point, “b” is not an accurate period. However, in this case, since the energization phase of the motor coil is switched by the start counter 38 in units of 60 electrical angles, the motor is driven at the third change point, and “c” is considered to be an accurate period. Therefore, “b” and “c” have different periods, and in the period TC, a rectangular signal RE1 having a period different from 16 periods is generated, while in the period TD, a rectangular signal RE1 having 16 periods is generated. Therefore, when the second change point of the composite signal RE2 is abnormal, the rotation of the motor coincides with the energization logic of the drive circuit after the start point of the period TD, that is, after the fourth change point of the composite signal RE2. Judgment can be made.

=== Operation of Sensorless Motor Drive Device ===
The operation of the sensorless motor driving apparatus according to the present invention will be described with reference to FIGS. FIG. 4 is a flowchart for explaining an example of the starting operation of the sensorless motor driving apparatus according to the present invention. FIG. 4 is a flowchart for switching the switching circuit 36 based on whether or not the second change point of the composite signal RE2 is normal.

First, when there is no motor start command from the motor stop state (S100) (S102: NO), the determination in step S102 is executed again.
When there is a motor start command (S100: YES), the start / normal control selection circuit 34 outputs a signal for switching the switching circuit 36 to the solid line side, that is, the output of the start-up oscillation circuit 32 (S104). And the starting mode which performs electricity supply control of a motor coil based on a starting oscillation signal is performed (S106). The start mode is a mode in which energization control of the motor is performed from a predetermined initial level of the mask signals UMASK, VMASK, and WMASK based on the start oscillation signal input to the mask circuit 26.
Next, the start / normal control selection circuit 34 counts the change points (edges) of the composite signal RE2 after the rotation of the rotor is detected (S108).

As described above, when the second change point of the composite signal RE2 is normal, the output of the multiplier circuit 30 becomes normal after the third change point of the composite signal RE2, and the second change point of the composite signal RE2 is If abnormal, it is considered that the output of the multiplier circuit 30 becomes normal after the fourth change point of the composite signal RE2. Therefore, when the second change point of the composite signal RE2 is abnormal (S110: NO), for example, when the motor is not driven normally at the second change point, the third change point of the composite signal RE2 is counted. (S112) Further, the fourth change point of the composite signal RE2 is counted (S114). Thereafter, a signal for switching the switching circuit 36 to the broken line side, that is, the output of the multiplication circuit 30 is output (S118). Then, a normal mode is executed in which energization control of the motor coil is performed with the rectangular signal RE1 output from the multiplier circuit 30 (S120). The normal mode is a mode in which the motor conduction control is performed based on the rectangular signal RE1 input to the mask circuit 26 and the back electromotive voltage generated in the motor coil.
When the second change point of the composite signal RE2 is normal (S110: YES), for example, when the motor is driven at the second change point, the third change point of the composite signal RE2 is counted (S116). Then, Step S118 and Step S120 are executed.

  In the present embodiment, when the second change point of the composite signal RE2 is normal, the timing of switching the switching circuit 36 is set as the third change point of the composite signal RE2, and when the second change point is abnormal, Although the switching timing of the switching circuit 36 is the fourth change point of the composite signal RE2, it may be switched after this change point. For example, when the second change point of the synthesized signal RE2 is normal, the switching circuit 36 is switched at the fourth and subsequent change points of the synthesized signal RE2, and when the second change point is abnormal, the fifth time of the synthesized signal RE2. The switching circuit 36 may be switched at a subsequent change point. The characteristics of the motor coil energization control can be improved by quickly switching the switching circuit 36 from the startup oscillation circuit 32 side to the multiplication circuit 30 side.

  Further, regardless of whether the second change point of the composite signal RE2 is normal or abnormal, the motor is driven at the fourth change point of the composite signal RE2. Therefore, the change point of the composite signal RE2 may be counted and the switching circuit 36 may be switched after the fourth change point.

  FIG. 5 is a flowchart for explaining an example of the starting operation of the sensorless motor driving apparatus according to the present invention. This flowchart describes a case where the switching circuit 36 is switched when the change point of the composite signal RE2 is counted four times.

First, if there is no motor start command from the motor stop state (S200) (S202: NO), the determination in step S202 is executed again.
When there is a motor start command (S200: YES), the start / normal control selection circuit 34 outputs a signal for switching the switching circuit 36 to the solid line side, that is, the output of the start-up oscillation circuit 32 (S204). Then, a start mode for performing energization control of the motor coil by the start oscillation signal is executed (S206).
Next, the start / normal control selection circuit 34 counts the changing points of the composite signal RE2 after the rotation of the rotor is detected (S208). Subsequently, it is determined whether or not there is commutation (electrical angle switching) by the activation counter (S209).
If there is commutation by the start counter (S209: YES), step S208 is executed again.
If there is no commutation by the start counter (S209: NO), it is determined whether or not the edge of the combined signal RE2 has been counted four times (S210). When the changing point of the composite signal RE2 is not the fourth time (S210: NO), step S209 is executed again. When the change point of the composite signal RE2 is the fourth time (S210: YES), a signal for switching the switching circuit 36 to the broken line side, that is, the output of the multiplication circuit 30 is output (S212). Then, the normal mode in which the energization control of the motor coil is controlled by the rectangular signal RE1 output from the multiplier circuit 30 is executed (S214).

  In this way, it is necessary to consider whether the second change point of the composite signal RE2 is normal or abnormal by counting the change points where the composite signal RE2 is considered to be normal and switching the switching circuit 36 after the change point. Therefore, the setting for switching the switching circuit 36 can be simplified. In this embodiment, the switching circuit 36 is switched when the change point of the composite signal RE2 is counted four times. However, after the fourth time, for example, the switch circuit 36 is switched when the change point of the composite signal RE2 is counted five times. May be.

  In FIG. 3, when “b” is an accurate period, the rectangular signal RE1 generated in the period TC is 16 periods. Accordingly, the activation / normal control selection circuit 34 may determine whether or not the rectangular signal RE1 has 16 periods in 1/2 cycle of the composite signal RE2, and may switch the switching circuit 36 when 16 periods have been reached. . At this time, since “b” and “c” are equal periods, the period TB and the period TC are also equal. Therefore, it may be determined whether or not the period of the 1/2 cycle of the continuous RE2 is equal, and the switching circuit 36 may be switched after the period of the 1/2 cycle of the continuous RE2 becomes equal.

  As described above, the sensorless motor driving apparatus according to the present invention performs energization control of the motor coil with the startup oscillation signal output from the startup oscillation circuit 32 when the motor is started, and the rectangular output from the multiplier circuit 30. After determining that the signal RE1 is normal, the energization control of the motor coil is performed by switching to the rectangular signal RE1, so that stable start-up can be performed when the sensorless motor is started.

  In addition, by counting the change point of the RE2 signal, for example, four times, it is possible to easily obtain the timing for switching the switching circuit 36 from the startup oscillation circuit 32 side to the multiplication circuit 30 side.

  Further, by changing the switching timing of the switching circuit 36 based on whether or not the second change point of the RE2 signal is normal, the output of the multiplier circuit 30 is changed from the output of the startup oscillation circuit 32 according to the startup state of the motor. You can switch to output. Even when the second change point of the RE2 signal is abnormal and the motor is not driven, the energized phase is switched at an electrical angle of 60 degrees by the start counter 38, so the fourth change point of the RE2 signal is switched by the switching circuit 36. Can be set to timing.

  In addition, since the multiplier circuit 30 is a DLL circuit that performs digital signal processing, the ½ period of the second rectangular signal can be matched with the n period of the third rectangular signal. After one cycle, the phase of the second rectangular signal and the phase of the third rectangular signal can be matched.

  In addition, since the start mode in which the energization of the motor is controlled by the start oscillation signal having the lowest constant frequency obtained from the PLL circuit of the start oscillation circuit 32 until the output of the multiplier circuit 30 becomes normal, the motor is started. Can do.

  As described above, the present embodiment has been specifically described based on the embodiment. However, the present embodiment is not limited to this, and various modifications can be made without departing from the scope of the present embodiment.

1 is a circuit block diagram of a sensorless motor driving apparatus according to the present invention. It is an operation | movement waveform diagram of the drive device of the sensorless motor concerning this invention. It is a figure for demonstrating the relationship between the rectangular signal RE1 and the synthetic signal RE2. It is a flowchart for demonstrating an example of starting operation | movement of the drive device of the sensorless motor concerning this invention. It is a flowchart for demonstrating an example of starting operation | movement of the drive device of the sensorless motor concerning this invention.

Explanation of symbols

2 U-phase coil 4 V-phase coil 6 W-phase coil 8, 10, 12, 14, 16, 18 MOSFET
22U, 22V, 22W Comparator 26 Mask circuit 28 Synthesis circuit 30 Multiplication circuit 32 Start-up oscillation circuit 34 Start-up / normal control selection circuit 36 Switching circuit 38 Start-up counter 40 Sensorless logic circuit

Claims (6)

The drive device for selectively energized to Rousset Nsaresumota the motor coil based on the counter electromotive voltage generated in the motor coil of a plurality of phases,
A plurality of comparators for comparing a coil voltage and a neutral point voltage of the motor coils of the plurality of phases and outputting a plurality of comparison signals;
A mask circuit that outputs a plurality of mask signals obtained by removing noise corresponding to kickback pulses from the plurality of comparison signals;
A sensorless logic circuit that outputs a signal for selectively energizing the motor coil based on the plurality of mask signals;
A start-up oscillation circuit for generating a first rectangular signal having a constant period;
A synthesis circuit that synthesizes the plurality of mask signals and generates a second rectangular signal whose period changes according to the rotational speed of the sensorless motor;
Each half cycle of the second rectangular signal, and a multiplier circuit for generating a third rectangular signal for multiplying a plurality of cycles of predetermined half cycle immediately before such a half period,
A switching circuit for switching the output of any one of the start-up oscillation circuit and the multiplication circuit to be supplied to the mask circuit as a signal for removing the noise ;
A discriminating circuit for discriminating whether or not the third rectangular signal generated in the period of the half cycle of the second rectangular signal is the plurality of cycles;
With
The discrimination circuit includes:
Based on the discrimination result when said third rectangular signal generated in the period of the half cycle of the second rectangular signal is first determined if there in the plurality of cycles, the switching circuit, the 1/2 cycle Thereafter, the sensorless motor driving device is switched from the start-up oscillation circuit side to the multiplication circuit side. The drive device for selectively energized to Rousset Nsaresumota the motor coil based on the counter electromotive voltage generated in the motor coil of a plurality of phases,
A plurality of comparators for comparing a coil voltage and a neutral point voltage of the motor coils of the plurality of phases and outputting a plurality of comparison signals;
A mask circuit that outputs a plurality of mask signals obtained by removing noise corresponding to kickback pulses from the plurality of comparison signals;
A sensorless logic circuit that outputs a signal for selectively energizing the motor coil based on the plurality of mask signals;
A rotor rotation detection circuit for detecting rotation of the rotor;
A start-up oscillation circuit for generating a first rectangular signal having a constant period;
A synthesis circuit that synthesizes the plurality of mask signals and generates a second rectangular signal whose period changes according to the rotational speed of the sensorless motor;
Each half cycle of the second rectangular signal, and a multiplier circuit for generating a third rectangular signal for multiplying a plurality of cycles of predetermined half cycle immediately before such a half period,
A switching circuit for switching the output of any one of the startup oscillation circuit and the multiplication circuit to be supplied to the mask circuit as a signal for removing the noise ;
A determination circuit for determining whether or not the level of the second rectangular signal has changed a predetermined number of times since the rotation of the rotor was detected;
With
The discrimination circuit includes:
Based on the determination result when it is determined that the level of the second rectangular signal has changed the predetermined number of times since the rotation of the rotor has been detected, the switching circuit causes the start-up oscillation after the predetermined number of change points. A sensorless motor driving apparatus, wherein switching from the circuit side to the multiplier circuit side is performed. The discrimination circuit includes:
When the motor is driven at the change point of the second rectangular signal indicating that the first half cycle of the second rectangular signal has elapsed since the rotation of the rotor was detected, the second rectangular After the next change point of the change point of the signal, the switching circuit is switched,
When the motor is not driven at the changing point of the second rectangular signal, the switching circuit is switched after the changing point after one cycle from the changing point of the second rectangular signal.
The sensorless motor driving apparatus according to claim 2, wherein: A start counter that counts the first rectangular signal when the motor is stopped;
4. When the start counter counts the first rectangular signal having a predetermined value, the energized phase of the motor coil is switched to a predetermined energized phase in units of an electrical angle of 60 degrees. A sensorless motor driving device according to any one of the above. The multiplier circuit is
5. The sensorless motor driving device according to claim 1, further comprising a DLL (Delay Locked Loop) circuit that executes digital signal processing. The starting oscillation circuit is:
A PLL (Phase Locked Loop) circuit;
The first rectangular signal is
6. The sensorless motor driving device according to claim 1, wherein the signal is a signal having the lowest frequency obtained from the PLL circuit in a stopped state of the motor.

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