JP5589382B2 - Brushless motor drive device - Google Patents

Description

  The present invention relates to a brushless motor drive device, and more particularly to a brushless motor drive device that detects and estimates the position of a rotor.

  Conventionally, as a brushless motor drive device, an inverter circuit that supplies a three-phase drive current to a brushless motor, a PWM circuit that supplies a sinusoidal PWM signal to the inverter circuit, a position by estimating the rotational position of the motor Various position estimation circuits that output signals, and motor drive devices that output control signals to the PWM circuit based on external speed command signals and position signals have been proposed. (For example, see Patent Document 1 and Patent Document 2)

  The brushless motor driving apparatus includes an output waveform forming circuit, and forms and outputs a modulation waveform of a control signal output to the PWM circuit based on the position signal.

  FIG. 7 is a diagram illustrating a method when the output waveform forming circuit in the brushless motor driving apparatus disclosed in Patent Document 1 forms a modulation waveform. The waveform diagram shown in FIG. 7A shows temporal changes of the position signals Hu, Hv, and Hw detected by three Hall ICs installed in the brushless motor. The waveform diagram shown in FIG. 7B is the modulated wave signals Su, Sv, Sw formed and output by the output waveform forming circuit.

By a counter circuit provided in the brushless motor driving device, for example, the time from the up edge of the position signal Hu (indicated by the arrow 100 in the figure) to the next down edge of the position signal Hw (indicated by the arrow 101 in the figure) Count. The time from this up edge 100 to the next down edge 101 is a time width of 60 ° phase. The obtained time width is indicated by a section 102 in the figure. Output waveform shaping circuit uses the time width T ₁₀₂ of the segment 102 as the time width data for forming the next 60 ° phase of the modulation waveform. In the output waveform forming circuit, the waveform data of the modulation waveform is stored. The waveform data includes 360 ° phase data of the modulated wave signal Su, 360 ° phase data of the modulated wave signal Sv, and 360 ° phase data of the modulated wave signal Sw, and the modulated wave signals Su, Sv, Each 360 ° phase data of Sw is composed of data divided into 6 × n, and each 60 ° phase is divided into n pieces of data (for example, 32 data). Then, in the output waveform forming circuit, a time width T ₁₀₂ of section 102, the modulation waveform is formed on the basis of the following 60 ° waveform data divided into n in the phase fraction of the section 103 shown by the arrow sign 103 ,Output.

Next, the counter circuit provided in the brushless motor driving device from the down edge of the position signal Hw (indicated by arrow 101 in the figure) to the next up edge of the position signal Hv (indicated by arrow 104 in the figure). Count the time. The time from the down edge 101 to the next up edge 104 is a time width corresponding to a 60 ° phase. The obtained time width is indicated by a section 105 in the figure. The output waveform forming circuit uses the time width T ₁₀₅ of this section 105 as time width data when forming a modulation waveform for the next 60 ° phase. In the output waveform forming circuit, a modulated waveform is formed based on the time width T ₁₀₅ of the section 105 and the waveform data divided into n pieces in the section 106 corresponding to the next 60 ° phase indicated by the arrow 106, and output. To do.

Further, the counter circuit provided in the brushless motor driving device from the up edge of the position signal Hv (indicated by the arrow 104 in the figure) to the next down edge of the position signal Hu (indicated by the arrow 107 in the figure). Count time. The time from the up edge 104 to the next down edge 107 is a time width corresponding to 60 ° phase. The obtained time width is indicated by a section 108 in the figure. Output waveform shaping circuit uses the time width T ₁₀₈ of the segment 108 as the time width data for forming the next 60 ° phase of the modulation waveform. The output waveform forming circuit forms a modulation waveform based on the n divided waveform data in the time width T ₁₀₈ of the section 108 and the time width 109 corresponding to the next 60 ° phase indicated by the arrow 109, Output.

  As described above, in the brushless motor driving apparatus disclosed in Patent Document 1, the time of the timing at which the three position signals change, that is, the time width corresponding to the 60 ° phase is measured by the pulse count. The measured time width is used as time width data for the 60 ° phase of the next modulation waveform.

  In the brushless motor driving device disclosed in Patent Document 2, as in the device described in Patent Document 1, the time at which the three position signals change, that is, the time width of 60 ° phase is measured by pulse counting. To do. The measured time width is used as time width data for the 60 ° phase of the next modulation waveform. However, in Patent Document 2, unlike Patent Document 1, the difference between the time width of the 60 ° phase measured two times before and the time width of the 60 ° phase measured one time before is a predetermined threshold value. In the following cases, the time width corresponding to the 60 ° phase measured immediately before is used as the time width data corresponding to the 360 ° phase of the modulation waveform. This will be described with reference to FIG.

  FIG. 8 is a diagram illustrating a method when the output waveform forming circuit in the brushless motor driving apparatus disclosed in Patent Document 2 forms a modulated waveform. The waveform diagram shown in FIG. 8A shows temporal changes of the position signals Hu, Hv, Hw detected by three Hall ICs installed in the brushless motor. The waveform diagram shown in FIG. 8B is the modulated wave signals Su, Sv, Sw formed and output by the output waveform forming circuit.

The counter circuit provided in the brushless motor driving device calculates the time from the down edge of the position signal Hv (indicated by the arrow 200 in the figure) to the next up edge of the position signal Hu (indicated by the arrow 201 in the figure). Count. The time from the down edge 200 to the next up edge 201 is a time width corresponding to a 60 ° phase. The obtained time width is indicated by a section 202 in the figure. Next, the time from the up edge (indicated by arrow 201 in the figure) of the position signal Hu to the next down edge (indicated by arrow 203 in the figure) of the position signal Hw is counted. The time from the up edge 201 to the next down edge 203 is a time width corresponding to a 60 ° phase. The obtained time width is indicated by a section 204 in the figure. When the time width for the 60 ° phase measured two times before indicated by the interval ₂₀₂ is T _202, and the time width for the 60 ° phase measured immediately before indicated by the interval 204 is T ₂₀₄ , the difference When ΔT (= T ₂₀₄ −T ₂₀₂ ) is equal to or greater than a predetermined threshold value, the output waveform forming circuit forms a modulated waveform in the same manner as shown in FIG.

On the other hand, when the difference ΔT (= T ₂₀₄ −T ₂₀₂ ) between the time width T ₂₀₂ and the time width T ₂₀₄ is equal to or smaller than a predetermined threshold, the output waveform forming circuit uses this interval when forming the modulation waveform. The time width T ₂₀₄ of ₂₀₄ is used as time width data for each 60 ° phase of the 360 ° phase shown by the sections 205, 206, 207, 208, 209, and 210 in FIG.

JP 2001-037279 A JP 2005-124367 A

  However, in the conventional apparatus as disclosed in Patent Documents 1 and 2, since the time width measured in advance is used as time width data for the next 60 ° phase, it is stable if the rotation speed of the motor is constant. Although the speed can be maintained, when the rotational speed of the motor fluctuates greatly, for example, there is a problem that followability is poor during acceleration / deceleration.

  FIG. 9 shows the time of changing timings of the three position signals in the brushless motor driving device disclosed in Patent Documents 1 and 2, that is, the time width of 60 ° phase is measured by the pulse count, and FIG. 6 is a diagram showing simulation results of a U-phase winding current, a V-phase winding current, and a W-phase winding current when the measured time width is used as time width data for the 60 ° phase of the next modulation waveform. is there. The waveform diagram shown in FIG. 9A shows temporal changes in the position signals Hu, Hv, Hw detected by three Hall ICs installed in the brushless motor. The waveform diagram shown in FIG. 9B shows the U-phase winding current, the V-phase winding current, and the W-phase winding current. As can be seen from FIG. 9, in this case, during acceleration / deceleration, large waveform distortion is generated as indicated by arrows 300, 301, 302, etc., indicating that motor followability is deteriorated.

  In view of the above problems, an object of the present invention is to provide a brushless motor driving device having good followability even when the motor rotational speed fluctuates greatly, for example, even during acceleration / deceleration.

In order to achieve the above object, a brushless motor driving apparatus according to the present invention is configured as follows.
A first brushless motor driving device (corresponding to claim 1) includes a driver circuit that supplies a driving current to the brushless motor, a predriver circuit that drives the driver circuit, and a sinusoidal PWM signal that is supplied to the predriver circuit. A PWM circuit that detects a rotational position of a brushless motor based on a signal from a magnetic element , outputs a position signal, and a modulated waveform in the PWM circuit based on an external speed command signal and a position signal A control unit that outputs and controls the control signal of the brushless motor, the control unit pulse-counts the time between the change timings of the three position signals output from the position detection unit, The time obtained by adding the difference between the previous count value and the previous count value to the previous count value is the time width data corresponding to the 60 ° phase of the next modulation waveform. Use Te, to form a modulated waveform, and outputs the modulated waveform to the PWM circuit, and drives the brushless motor.
In the second brushless motor driving device (corresponding to claim 2), the control unit preferably counts the time based on the change timing of the position signal from the position detection unit, and thereby obtains it. A counter circuit that outputs a counter value, an output waveform forming unit that forms a modulation waveform based on a speed command signal from the outside and the counter value from the counter circuit, and outputs the modulation waveform to the PWM circuit It is characterized by.
In the third brushless motor driving apparatus (corresponding to claim 3), in the above configuration, the output waveform forming unit is preferably configured such that the output waveform forming unit ends the output of the last waveform data of the modulation waveform and the edge timing of the position signal If the edge timing of the position signal does not come even after the output of the last waveform data of the modulated waveform is completed, the last waveform data will continue to be output until the edge timing. It is characterized by resetting.
In the fourth brushless motor drive device (corresponding to claim 4), in the above configuration, preferably, the output waveform forming unit is configured to output the end timing of the last waveform data of the modulation waveform and the timing of the edge of the position signal. If the timing of the edge of the position signal comes before the output of the last waveform data of the modulation waveform, the output of the modulation wave signal for the next 60 ° phase is started at that time. It is characterized by.

  According to the present invention, the control unit performs pulse counting of the time between the change timings of the three position signals output from the position detection unit, and sets the difference between the previous count value and the previous count value to 1. The time added to the previous count value is used as time width data for the 60 ° phase of the next modulation waveform to form a modulation waveform, and the modulation waveform is output to the PWM circuit to drive the brushless motor. Therefore, the followability can be improved even when the rotational speed of the motor varies greatly.

It is a block diagram which shows the structure of the drive device of the brushless motor which concerns on this embodiment of this invention. It is a figure which shows the method when the output waveform formation part in the drive device of the brushless motor which concerns on this embodiment of this invention forms a modulation wave waveform, (a) is three Hall IC installed in the brushless motor FIG. 4B shows a time change of the position signal detected by (1), and (b) shows a modulated wave waveform formed and output by the output waveform forming unit. It is a figure explaining the method of forming the modulation wave waveform Sv55 of the area | region 55 among the modulation wave waveforms Sv shown in FIG. 2 by an output waveform formation part. Is a diagram timing of rising edge of the end timing and the position signal Hv will be described processing in the output waveform forming part of the case does not match the output during the time t of the last of the waveform data D _n of the modulated waveform SV55. Is a diagram timing of rising edge of the end timing and the position signal Hv will be described processing in the output waveform forming part of the case does not match the output during the time t of the last of the waveform data D _n of the modulated waveform SV55. It is a figure which shows the simulation result of the U-phase winding current, the V-phase winding current, and the W-phase winding current in the brushless motor driving apparatus according to the embodiment of the present invention. It is a figure which shows the method when the output waveform formation circuit in the drive device of the conventional brushless motor forms a modulation wave waveform. It is a figure which shows the method when the output waveform formation circuit in the drive device of the conventional brushless motor forms a modulation wave waveform. It is a figure which shows the simulation result of the U-phase winding current in the conventional brushless motor drive device, the V-phase winding current, and the W-phase winding current.

  DESCRIPTION OF EMBODIMENTS Preferred embodiments (examples) of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a block diagram showing a configuration of a brushless motor driving apparatus according to the present embodiment of the present invention. The brushless motor driving apparatus 10 includes a driver circuit 11, a power supply 12, a pre-driver circuit 13, a PWM circuit 14, a basic waveform forming unit 15, a position detecting unit 16, a counter circuit 17, an output waveform forming unit 18, and three Hall ICs 19u. , 19v, 19w. The control unit 5 includes a counter circuit 17 and an output waveform forming unit 18.

  The driver circuit 11 is an inverter circuit (not shown) that forms a three-phase bridge circuit using six switching elements composed of diodes D1 to D6 connected in reverse parallel to the switching transistors Tr1 to Tr6, and is supplied from a power supply 12. Drive by DC voltage. The six switching transistors are turned on / off by a PWM signal input from the PWM circuit 14 via the pre-driver circuit 13, so that the three-phase stator windings 20 u, 20 v, and 20 w have a three-phase drive current Iu. , Iv, Iw are supplied.

  The three Hall ICs 19u, 19v, 19w detect the positions of the S pole and N pole of the rotor of the motor 21 and output position signals Hu, Hv, Hw to the position detector 16.

  The position detection unit 16 outputs the detected position signals Hu, Hv, Hw to the counter circuit 17 and the output waveform forming unit 18.

  The counter circuit 17 counts the time between the change timings of the position signal based on the position signal from the position detection unit 16, and outputs the counter value obtained thereby to the output waveform forming unit 18.

  The output waveform forming unit 18 forms modulated wave signals Su, Sv, Sw based on the speed command signal A from the outside, Hu, Hv, Hw from the position detection unit 16 and the counter value from the counter circuit 17, The modulated wave signals Su, Sv, Sw are output to the PWM circuit 14.

  The PWM circuit 14 compares the modulated wave signals Su, Sv, Sw output from the output waveform forming unit 18 with the triangular wave output from the basic waveform forming unit 15, and is modulated by the modulated wave signals Su, Sv, Sw. The PWM signal is output to the pre-driver circuit 13.

  The pre-driver circuit 13 outputs signals for driving the switching transistors Tr1 to Tr6 of the driver circuit 11 in accordance with the PWM signal input from the PWM circuit 14.

  Next, the operation of the brushless motor driving apparatus 10 according to the present embodiment will be described. The feature of the brushless motor driving apparatus 10 of this embodiment is that the control unit 5 counts the time between the change timings of the three position signals output from the position detection unit 16 and changes the three position signals. The time obtained by adding the difference between the previous count value and the previous count value of the count values between timings to the previous count value is used as time width data for the 60 ° phase of the next modulation waveform. Then, modulated wave signals Su, Sv, Sw are formed based on the waveform data divided into n pieces for the next 60 ° phase, and the modulated wave signals Su, Sv, Sw are output to the PWM circuit 14, The brushless motor 21 is driven based on those signals.

  FIG. 2 is a diagram showing a method when the output waveform forming unit 18 in the brushless motor driving apparatus 10 forms the modulated wave signals Su, Sv, Sw. The waveform diagram shown in FIG. 2A is a time change of the position signals Hu, Hv, Hw detected by the position detector 16 based on signals from the three Hall ICs 19u, 19v, 19w installed in the brushless motor 21. Is shown. The waveform diagram shown in FIG. 2B is the waveform of the modulated wave signals Su, Sv, Sw formed and output by the output waveform forming unit 18.

  By the counter circuit 17 provided in the driving device 10 of the brushless motor 21, from the down edge of the position signal Hv (indicated by the arrow 50 in the figure) to the next up edge of the position signal Hu (indicated by the arrow 51 in the figure). Count the time. The time from this down edge 50 to the next up edge 51 is a time width of 60 ° phase. The obtained time width is indicated by a section 52 in the figure. Next, the time from the up edge of the position signal Hu (indicated by the arrow 51 in the figure) to the next down edge of the position signal Hw (indicated by the arrow 53 in the figure) is counted. The time from the up edge 51 to the next down edge 53 is a time width of 60 ° phase. The obtained time width is indicated by a section 54 in the figure.

The output waveform forming unit 18 determines the difference ΔT ₁ (= T ₅₄ −T ₅₂₎ between the time width T ₅₄ for the 60 ° phase measured in the section ₅₄ and the time width T ₅₂ for the 60 ° phase measured in the section _52. ) And the time obtained by adding the difference ΔT ₁ (= T ₅₄ −T ₅₂ ) to the time width T ₅₄ of the section 54 is used as the time width T _{55 corresponding to} the 60 ° phase of the section 55 of FIG. Su, Sv, Sw are formed and output. Here, T ₅₂ and T ₅₄ are measured by the counter circuit 17.

FIG. 3 is a diagram for explaining how the output waveform forming unit 18 forms a modulation waveform in the range indicated by the section 55 of the modulation waveform Sv shown in FIG. The output waveform forming unit 18 stores the waveform data of the modulated wave signal. The waveform data includes data for the 360 ° phase of the modulated wave signal Su, data for the 360 ° phase of the modulated wave signal Sv, and data for the 360 ° phase of the modulated wave signal Sw, and the modulated wave signal Su, The data for each 360 ° phase of Sv and Sw consists of data divided into 6 × n pieces, and data D ₁ , D ₂ , D ₃ ,... Obtained by dividing each 60 ° phase portion into n pieces. -It _{consists of} Dn (for example, n = 32). Then, the output waveform forming unit 18 is divided into n sections 55 by a time width T _{55 obtained} by adding the difference ΔT ₁ (= T ₅₄ −T ₅₂ ) to the time width T ₅₄ indicated by reference numeral 54 in FIG. waveform data _{D 1,} D _2, D 3 and to form a modulated waveform as · · · _{D n} falls at equal time intervals, and outputs. That is, the time t during which each piece of the waveform data D ₁ , D ₂ , D ₃ ,... D _n that is divided into n pieces in the section 55 continues is 1 / n of the time width T ₅₅ of the section 55. (That is, t = T ₅₅ × (1 / n)). Then, the waveform data D ₁ , D ₂ , D ₃ ,... D _n are sequentially output with this duration t, so that the modulated waveform Sv55 corresponding to the 60 ° phase indicated by the section 55 is output. Is done. Here, any one of Su, Sv, and Sw is stored as the data of the modulated wave signal, and the other two can be used with a phase shift of 120 ° or 240 °.

4 and 5, the processing of the output waveform forming section 18 when the timing of the rising edge 56 of the end timing and the position signal Hv output during the time t of the last of the waveform data D _n of the modulation waveform Sv55 do not match FIG. Figure If the output during the time t of the last of the waveform data D _n of 4 modulation waveform Sv55 as shown in does not come timing (time) t _B of the rising edge 56 of the position signal Hv be terminated at time t _A The waveform data D _n continues to be output until the timing t _B of the up edge 56 and is reset at the timing t _B of the up edge 56.

Further, as shown in FIG. 5, when the timing (time) t _c of the up edge 56 of the position signal Hv comes before the output of the last waveform data D _n of the modulation waveform Sv55 during the time t, At the time t _c , the output waveform forming unit 18 starts outputting a modulated wave signal for the next 60 ° phase. 3 to 5 show the method of forming the modulated wave signal Sv, the modulated wave signals Su and Sw are also formed in the same manner as the method of forming the modulated wave signal Sv as a waveform obtained by shifting Sv by 120 ° and 240 °. Formed.

Next, the formation by the output waveform forming unit 18 of the modulated wave signals Su, Sv, Sw corresponding to the 60 ° phase indicated by the section 58 shown in FIG. 2 will be described. By the counter circuit 17 provided in the driving device 10 of the brushless motor 21, from the down edge of the position signal Hw (indicated by a section 53 in the figure) to the next up edge of the position signal Hv (indicated by a section 56 in the figure). Count the time. The time from the down edge 53 to the next up edge 56 is a time width of 60 ° phase. The obtained time width is indicated by a section 57 in the figure. The output waveform forming unit 18 determines the difference ΔT ₂ (= T ₅₇ −T) between the time width T ₅₇ for the 60 ° phase measured in the section ₅₇ and the time width T ₅₄ for the 60 ° phase measured in the section 54. ₅₄ ), and the time obtained by adding the difference ΔT ₂ (= T ₅₇ −T ₅₄ ) to the time width T ₅₇ shown in the section 57 is used as the time width T ₅₈ corresponding to the 60 ° phase shown in the section 58 of FIG. The modulated wave signals Su, Sv, Sw are formed and output. The modulation waveform is formed in the same manner as the modulation wave signal Sv55 shown in FIGS.

  FIG. 6 is a diagram illustrating simulation results of the U-phase winding current, the V-phase winding current, and the W-phase winding current in the driving device 10 of the brushless motor 21 according to the present embodiment. The waveform diagram shown in FIG. 6A shows temporal changes of the position signals Hu, Hv, Hw detected by the three Hall ICs 19u, 19v, 19w installed in the brushless motor 21. The waveform diagram shown in FIG. 6B shows the U-phase winding current, the V-phase winding current, and the W-phase winding current. As can be seen from FIG. 6, in this case, the waveform distortion during acceleration / deceleration is small, and it can be seen that the motor followability is good.

  As described above, according to the present embodiment, the control unit 5 pulse-counts the time between the change timings of the three position signals output from the position detection unit 16, and between the change timings of these three position signals. The time obtained by adding the difference between the previous count value and the previous count value to the previous count value is used as the time width data for the 60 ° phase of the next modulation waveform. Since the modulation waveforms Su, Sv, Sw are formed, the modulation waveforms are output to the PWM circuit 14 and the brushless motor 21 is driven, the followability can be improved even when the rotational speed of the motor varies greatly.

  The configurations, shapes, sizes, and arrangement relationships described in the above embodiments are merely schematically shown to the extent that the present invention can be understood and implemented, and the numerical values and the compositions (materials) of the respective components Is just an example. Therefore, the present invention is not limited to the described embodiments, and can be variously modified without departing from the scope of the technical idea shown in the claims.

  The brushless motor drive device according to the present invention is used as a drive source for a fan device, a pump, a washing machine, a tableware dryer, or the like.

DESCRIPTION OF SYMBOLS 5 Control part 10 Brushless motor drive device 11 Driver circuit 12 Power supply 13 Pre-driver circuit 14 PWM circuit 15 Basic waveform formation part 16 Position detection part 17 Counter circuit 18 Output waveform formation part 19u, 19v, 19w Hall IC
20u, 20v, 20w Stator winding 21 Brushless motor

Claims (4)

A driver circuit for supplying a drive current to the brushless motor;
A pre-driver circuit for driving the driver circuit;
A PWM circuit for supplying a sinusoidal PWM signal to the pre-driver circuit;
A position detector that detects a rotational position of the brushless motor based on a signal from the magnetic element and outputs a position signal;
A control unit that outputs and controls a control signal of a modulation waveform to the PWM circuit based on an external speed command signal and the position signal;
A brushless motor drive device comprising:
The controller is
A time obtained by pulse-counting the time between the change timings of the three position signals output from the position detection unit, and adding the difference between the previous count value and the previous count value to the previous count value Is used as time width data for the 60 ° phase of the next modulation waveform, forms a modulation waveform, outputs the modulation waveform to the PWM circuit, and drives the brushless motor. Drive device.   The control unit counts time based on the change timing of the position signal from the position detection unit, outputs a counter value obtained thereby, a speed command signal from the outside, and a counter value from the counter circuit 2. The brushless motor driving apparatus according to claim 1, further comprising: an output waveform forming unit configured to form a modulation waveform based on the waveform and output the modulation waveform to the PWM circuit.   The output waveform forming unit is configured so that the end timing of output of the last waveform data of the modulation waveform does not coincide with the timing of the edge of the position signal, and the position of the output waveform forming unit is not limited even when the output of the last waveform data of the modulation waveform is completed. 3. The brushless motor driving apparatus according to claim 2, wherein when the edge timing of the signal does not come, the last waveform data is continuously output until the edge timing and is reset at the edge timing. The output waveform forming unit is configured to output the final waveform data before outputting the last waveform data of the modulation waveform when the output timing of the last waveform data of the modulation waveform does not coincide with the edge timing of the position signal. 3. The brushless motor driving device according to claim 2, wherein when the timing of the edge of the signal comes, output of a modulated wave signal for the next 60 [deg.] Phase is started at that time.