JP2011045217A - Brushless motor drive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a brushless motor drive which can reduces an adjustment time, without causing increase in the manufacturing cost. <P>SOLUTION: The brushless motor drive includes a bridge circuit 2, a hole IC 31 serving as a position detecting means, a phase generating means 4, a current detecting means 5, a speed detecting means 6, a speed comparing means 7, a speed controlling means 8, a drive signal generating means 9 and a lead angle adjusting means 10. The lead angle adjusting means 10 converts detected currents c1 and c2 into DC detected currents which are defined on a d-q rotary coordination system, based on a position signal a, and adjusts a lead angle rate f based on the DC detected currents. As a result, since optimum lead angle adjustment is performed for each of a plurality of devices having different characteristics and eliminates the need for detecting the maximum of a sine waveform, adjustment time is reduced. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a brushless motor driving apparatus that adjusts a lead angle by flowing a periodic sine wave current through a coil to adjust a phase difference between a rotational position of a rotor and a sine wave current in order to rotate a brushless motor.

In the brushless motor drive, a sine wave drive in which a sine wave current is supplied to the armature coil is often used for the purpose of reducing torque fluctuation and quieting. An example of the configuration will be described with reference to FIGS. 17, 4, and 5.
First, FIG. 17 shows a configuration example of a conventional apparatus. In the brushless motor 1, for example, a three-phase armature coil is Y-connected, and a permanent magnet as a rotor is disposed at a position facing the armature coil.
The bridge circuit 2 includes a plurality of switching elements and diodes, and is connected to the armature coil of the brushless motor 1. In many cases, the position detection means 3 uses a Hall IC, detects the position of the rotor of the brushless motor, and outputs a periodic position signal a.
The encoder 41 is connected to the shaft of the rotor and outputs a position change signal g corresponding to a change in the position of the rotor. The phase generation means 4 outputs absolute phase information b0 within one cycle of the position signal a in accordance with the position signal a and the position change signal g.

The speed detecting means 6 detects the rotational speed of the rotor according to the position change signal g and outputs a detected speed d0. The speed comparison means 7 compares the target speed d1 with the detected speed d0 and outputs a speed difference d2.
The speed control means 8 outputs a drive voltage signal e so that the rotor follows the target speed based on the speed difference d2. The adding means 11 outputs absolute phase information (after advance) b1 obtained by adding the advance amount f as an offset to the absolute phase information b0.
Based on the absolute phase information (after advance) b1, the drive signal generation means 9 generates a three-phase sine wave waveform with a normalized amplitude and a phase difference of 120 degrees from each other, as shown in FIG. Further, the three-phase sine wave waveform is PWM-modulated by comparing the signals Vu, Vv, and Vw multiplied by the drive voltage signal e with the triangular wave Vt that is the carrier wave, and as shown in FIG. Based on the PWM-modulated sine wave waveform, the switching device driving signal UH for the upper arm of each phase in the bridge circuit 2 and the driving device for the lower arm switching device are added with the through current prevention section td. Output a signal.
The above is a configuration example of a conventional device for driving a brushless motor with a sine wave.

Hereinafter, the advance angle adjustment for determining the advance angle amount f will be described. In the sine wave drive, there is a problem that the drive efficiency of the motor is remarkably lowered due to the phase difference between the induced voltage generated in the armature coil and the sine wave current.
Therefore, in order to optimally set the phase difference between the induced voltage and the sine wave current, advance angle adjustment is performed to adjust the phase of the drive signal in accordance with the absolute phase information.
For example, a conventional method for adjusting the first advance angle will be described. In a state where the speed is controlled by the configuration of the driving device described above, the advance amount f to be added to the absolute phase information b0 is adjusted so that the amplitude of the sine wave current is minimized.
Hereinafter, a configuration example will be described with reference to FIG. The current amplitude detection means 51 includes a peak hold circuit (not shown), detects the amplitude of the sine wave current with respect to the sine wave current flowing through the armature coil, and outputs a detected current amplitude c0.
The advance angle adjusting means 10 adjusts the advance angle amount f so that the detected current amplitude c0 is minimized.

  Next, a conventional method for adjusting the second advance writing angle will be described. A data table of optimum advance angle adjustment values corresponding to the detection speed output from the speed detection means and the value of the drive voltage signal output from the speed control means is created in advance by experiment or calculation of a mathematical model. The sine wave drive of the motor is performed, and the advance angle is adjusted in a short time by setting the advance amount f to a value that is estimated to be optimal based on the data table from the detected speed and the value of the drive voltage signal. (For example, refer to Patent Document 1).

In the first conventional method for adjusting the advance angle, it is necessary to detect the amplitude of the sine wave current in order to adjust the advance angle. However, since the phase of the sine wave current varies depending on the amount of advance, The timing at which the waveform of the wave current becomes maximum cannot be known.
Therefore, a means for detecting the maximum value of the sine wave current, such as a peak hold circuit, is required, resulting in an increase in cost. Further, since the maximum value of the sine wave waveform can be measured only once in one cycle of the sine wave waveform, there is a problem that adjustment takes time.
In the second conventional method for adjusting the advance angle, the amount of advance angle is determined based on a data table created using an adjustment value obtained by an actual machine experiment or calculation of a mathematical model.
However, when there are a plurality of devices due to mass production or the like, there is an error in the characteristics of the actual device or mathematical model for which the adjustment value stored in the data table is obtained and the actual device, and the advance amount is optimally set. There was a problem that it was not always.

The present invention has been made in view of the above situation, and an object of the present invention is to provide a brushless motor driving device capable of shortening the adjustment time without increasing the manufacturing cost.
Another object of the present invention is to provide a brushless motor driving device that can adjust the lead angle optimally for each solid and can shorten the adjustment time.

  In order to achieve the above object, an invention according to claim 1 is a brushless motor driving device that rotates a rotor by causing a periodic current to flow through an armature coil of a plurality of phases according to a rotational position of the rotor. A switching circuit and a diode configured to supply a current to the armature coil, position detecting means for outputting a periodic position signal a according to the position of the rotor, and rotation of the rotor Phase generating means for outputting absolute phase information b0 within one cycle of the position signal a according to a signal based on the position, and detection currents c1 and c2 of two phases according to the phase current flowing through the armature coil The current detection means for outputting, the speed detection means for outputting the detection speed d0 according to the rotation speed of the rotor, the target speed d1 of the rotor and the detection speed d0 are compared, and the speed difference d2 is output. Speed comparison means, speed control means for outputting a drive voltage signal e so that the rotational speed of the rotor follows a target speed in accordance with the speed difference d2, and a sine wave current applied to the armature coil. The driving signal generation that outputs the switching element driving signal that drives the switching element of the bridge circuit according to the absolute phase information b0 and the advance amount f that gives a predetermined offset to the absolute phase information so as to flow And an advance angle adjusting means for converting the detected currents c1 and c2 into a DC detection current of a dq rotation coordinate system based on the position signal a and adjusting the advance amount f based on the DC detection current. It is characterized by providing.

The invention described in claim 2 is a brushless motor driving apparatus that rotates a rotor by causing a periodic current to flow through an armature coil of a plurality of phases in accordance with a rotational position of the rotor, and includes a switching element and a diode. A bridge circuit for supplying a current to the armature coil, a position detection means for outputting a periodic position signal a according to the position of the rotor,
Phase generation means for outputting absolute phase information b0 within one cycle of the position signal a according to a signal based on the rotational position of the rotor, and detection of two phases according to a phase current flowing through the armature coil The current detection means for outputting the currents c1 and c2, the speed detection means for outputting the detection speed d0 according to the rotation speed of the rotor, the target speed d1 of the rotor and the detection speed d0 are compared, Speed comparison means for outputting a difference d2, speed control means 8 for outputting a drive voltage signal e so that the rotational speed of the rotor follows a target speed in accordance with the speed difference d2, and the armature coil A switching element for driving the switching element of the bridge circuit according to the absolute phase information b0 and an advance amount f that gives a predetermined offset to the absolute phase information b0 so that a sine wave current flows in Drive signal generating means for outputting a motion signal,
An advance angle adjusting means for converting the detected currents c1 and c2 into a DC detection current of a dq rotation coordinate system based on the absolute phase information b0 and adjusting the advance amount f based on the DC detection current; It is characterized by providing.

According to a third aspect of the present invention, in the brushless motor driving device according to the first or second aspect, the position detecting means is a Hall sensor.
According to a fourth aspect of the present invention, in the brushless motor driving device according to any one of the first to third aspects, the phase generating means outputs an output pulse of the encoder synchronized with the rotational position of the rotor. And having the counter loaded with a predetermined value in accordance with the position signal a, and outputting the absolute position information b0 in accordance with the count value of the counter.

According to a fifth aspect of the present invention, in the brushless motor driving device according to any one of the first to third aspects, the phase generating means outputs an output pulse of the resolver synchronized with the rotational position of the rotor. And having the counter loaded with a predetermined value in accordance with the position signal a, and outputting the absolute position information b0 in accordance with the count value of the counter.
A sixth aspect of the present invention is the brushless motor driving device according to any one of the first to third aspects, wherein the phase detecting means is phase-synchronized with the position signal a and the position signal It is characterized by comprising a PLL (Phase Locked Loop) that outputs absolute phase information b0 within one period.

According to the present invention, in the advance angle adjustment of a device that drives a brushless motor with a sine wave, a phase that periodically changes based on the detected phase current and information indicating the position of the rotor in the state of speed control. By converting an electric current into a DC detection current of a dq rotating coordinate system and configuring an advance angle adjustment unit that adjusts the advance amount based on the DC detection current, it is possible for each of a plurality of devices having different characteristics to Therefore, it is possible to adjust the lead angle optimum for the sine wave, and it is not necessary to detect the maximum value of the sine wave waveform, so that the adjustment time can be shortened.
Furthermore, since the absolute position information for generating the sine wave waveform is generated only from the position signal, the position change detecting means becomes unnecessary, and the manufacturing cost of the apparatus can be reduced.

1 is a block diagram illustrating a configuration of a brushless motor driving apparatus according to a first embodiment of the present invention. It is a figure which shows the phase relationship of the induced voltage of an armature coil, and the output of Hall IC. It is a figure which shows operation | movement of the phase generation means in 1st Embodiment and 2nd Embodiment. It is a figure which shows the sine wave waveform which a drive signal production | generation means produces | generates. It is a figure which shows the production | generation of a switching element drive signal in a drive signal production | generation means. It is a figure which shows the relationship between a 3-axis fixed coordinate system and a 2-axis rotation coordinate system. It is a flowchart which shows the operation | movement of a lead angle adjustment. It is a block diagram of a brushless motor driving apparatus according to the second embodiment. It is a block diagram of the configuration of a brushless motor drive device according to a third embodiment. It is a figure which shows the structure of PLL in 3rd Embodiment. It is a figure which shows the operation | movement of PLL in 3rd Embodiment. It is a figure which shows the structure of a speed control means. It is a figure which shows the example of a waveform of the phase current value in case an advance amount is optimal. It is a figure which shows the example of a waveform after coordinate conversion in case an advance amount is optimal. It is a figure which shows the example of a waveform of a phase current value in case an advance amount is not optimal. It is a figure which shows the example of a waveform after coordinate conversion in case an advance amount is not optimal. It is a block diagram of a conventional brushless motor driving device.

Embodiments of the present invention will be described below with reference to the drawings.
First, the first embodiment will be described. FIG. 1 is a block diagram illustrating a configuration of a brushless motor driving device according to the present embodiment.
The brushless motor 1 has a rotor in which a three-phase armature coil is Y-connected and a permanent magnet is disposed at a position facing the armature coil, and a periodic current is passed through the armature coil according to the position of the rotor. As a result, the rotor rotates. The brushless motor 1 in this embodiment has a magnetic flux sine wave distribution in which a magnetic flux passing through a coil of a permanent magnet changes in a sine wave shape with respect to the position of the rotor. Notation).
The bridge circuit 2 is a three-phase full bridge circuit including switching elements and diodes of the upper arm and the lower arm, and is connected to the armature coil of the brushless motor 1.

The Hall IC 3 as position detecting means detects the position of the rotor and outputs a position signal a. The position signal a is composed of three-phase hall signals Hu, Hv, and Hw, which are binary signals having a phase difference of 120 degrees from each other. In addition, when the induced voltages generated in the armature coils of the U-phase, V-phase, and W-phase during rotation of the rotor are Eu, Ev, and Ew, the phase relationship between the Hall signal and the induced voltage is illustrated. It is shown in 2.
The encoder 41 is connected to the rotor shaft, and outputs a position change signal g, which is a pulse signal, in response to a change in the rotor position. The rotor position detection resolution of the encoder 41 outputs 192 times the number of rotor pole pairs per rotation of the rotor. Note that the same applies to the resolver, not the encoder, as long as the number of pulses for the rotor position change is the same.
The position signal a from the Hall IC 3 and the position change signal g from the encoder 41 are “signals based on the rotational position of the rotor”.

  The phase generation means 4 outputs absolute phase information b0 within one period of the position signal a based on the position signal a and the position change signal g. The absolute position information b0 represents one cycle of the position signal a with a resolution of 192 counts (hereinafter referred to as [cnt]), and one cycle of the position signal is an electrical angle of 360 degrees.

  Hereinafter, generation of the absolute position information b0 will be described with reference to FIG. 3, Table 1, and Expression 1. The phase generation unit 4 includes a counter unit (not shown) therein, and repeatedly counts up the number of pulses of the input position change signal g within a range of 0 to 191 [cnt]. However, when any of Hu, Hv, and Hw of the position signal a is changed, a predetermined value is loaded into the counter according to the combination of the values of Hu, Hv, and Hw. The position signal a changes at six points in one cycle of the position signal a. Table 1 shows values to be loaded to the counter in each case.

Upon receiving the current detection trigger cdt, the current detection means 5 detects the current values flowing in the U phase and V phase of the armature coil and outputs them as c1 and c2, respectively.
The speed detector 6 measures the pulse interval of the position change signal g and outputs a detection speed d0 based on the pulse interval.
The speed comparison means 7 compares the target speed d1 with the detected speed d0 and outputs a speed difference d2.
The speed control means 8 outputs a drive voltage signal e so that the rotor follows the target speed based on the speed difference d2. For example, as shown in FIG. 12, it is composed of a speed proportional system and a speed integral phase system filter.
The adding means 11 outputs absolute phase information (after advance) b1 obtained by adding the advance amount f as an offset to the absolute phase information b0. The unit of the advance amount f is [cnt] similarly to the absolute phase information. For example, when b0 = 190 [cnt] and f = 3 [cnt], b1 = 1 [cnt]. The range 0-191 [cnt] shall be repeated.
The advance angle adjusting means 10 optimally sets the advance angle amount f based on the detected currents c1 and c2 and the phase signal a. The operation for determining the optimum advance amount will be described later.
The drive signal generator 9 outputs a drive signal for the switching element of the bridge circuit 2 based on the absolute phase information (after advance) b1.

Hereinafter, the operation of the drive signal generating means will be described with reference to FIGS. First, based on the absolute phase information (after advance) b1, the amplitude is normalized, and a three-phase sine wave waveform having a phase difference of 120 degrees in electrical angle (phase difference of 64 [cnt]) is generated.
Next, as shown in FIG. 4, PWM modulation is performed by comparing signals Vu, Vv, and Vw obtained by multiplying the three-phase sinusoidal waveform by the value of the drive voltage signal e with a triangular wave Vt that is a carrier wave. At this time, as shown in FIG. 5 (only the U phase is shown), the signal is compared with the carrier wave Vt, and a signal delayed by the interval td is output as the switching element drive signal UH for the U phase upper arm.
The drive signal UH is inverted so that the switching element of the lower arm operates in a complementary manner with respect to the upper arm, and a section td is added before and after the ON section to add a through current prevention OFF section. The switching element drive signal UL is output.
The above is the configuration of the apparatus for driving the brushless motor in a sine wave in the present embodiment.

The operation of the advance angle adjusting means 10 for determining the optimum advance angle amount f will be described below. First, phase current coordinate conversion in a brushless motor will be described with reference to FIG.
Assuming that the currents flowing through the three-phase armature coils are iu, iv, and iw, respectively, the brushless motor 1 has the relationship shown in Equation 2 because it is Y-connected. The U-phase and V-phase phase current values are converted from the three-axis fixed coordinate system of the UVW axis to the two-axis rotary coordinate system having the relationship shown in FIG. 1 is converted into two direct currents, a torque current iq that contributes to the torque generated by 1 and a reactive current id that does not contribute to the torque. At this time, the coordinate conversion is performed by the calculation shown in Expression 3 from FIG. 6 and Expression 2.
In FIG. 1, c1 corresponds to iu and c2 corresponds to iv. Further, θ in FIG. 6 and Expression 3 is a value obtained by converting the absolute phase information b0 into an angle by Expression 1.

Next, the operation of the advance adjustment means 10 for determining the optimum advance amount f will be described. First, in this embodiment, the brushless motor 1 is SPM, and the efficiency is maximum when the reactive current id = 0.
Here, FIGS. 13, 14, 15 and 16 show examples of waveforms indicating the phase currents iu and iv and the DC currents id and iq after coordinate conversion. FIGS. 13 and 14 show the case where the advance amount f is optimally set, and FIGS. 15 and 16 show the case where the advance amount f is not optimal, both at the same rotational speed and load torque. is there.
Although the current iq that contributes to the torque is the same because of the same rotation speed and load torque, the reactive current id that does not contribute to the torque in FIG. 16 is not zero, and the amplitude of the sine wave current in FIG. Compared with the case of 13, it is larger. That is, the case where the reactive current id = 0 corresponds to the case where the amplitude of the sine wave current is minimized when the motor rotates at a constant speed in Patent Document 1.
The advance amount f that maximizes the efficiency is the optimum advance amount, and FIG. 7 shows a flowchart of the advance angle adjustment operation for determining the optimum value of the advance amount f.

Hereinafter, the operation of the advance angle adjustment will be described. First, n candidates fdata (j) (j = 0, 1,..., N−1) of n optimal advance amounts f are stored in a memory (not shown) in advance. After the advance angle adjustment is started, the adjustment count j is first initialized (S001). Next, fdata (j) is set to the advance amount f, and the advance amount is changed (S002). In order to wait until the current response to the change of the advance angle is settled, a predetermined time is waited (S003). When a change in the position signal a is detected after S003 is completed, a current detection trigger cdt is output to the current detection means 5 so as to execute current detection.
After the current detection by the current detection means 5 is completed, the detection currents c1 and c2 are received. Further, it is determined which edge of the position signal a is obtained, and absolute phase information is obtained. The absolute phase information is the same as the value loaded to the counter when the position signal a changes in the phase generation means 4 shown in FIG. 3 and Table 1 (S004).

Next, coordinate conversion shown in Expression 3 is performed to obtain a reactive current id. At this time, iu and iv in Equation 3 are the values of the detection currents c1 and c2, and θ is a value obtained by converting the absolute phase information into an electrical angle by Equation 1 (S005). The value of the reactive current id obtained in S005 is stored in a memory (not shown) (S006). The adjustment count j is incremented (S007).
It is determined whether or not the adjustment count has reached a predetermined count. If not, the process returns to S002 (S008). Among the ids stored in S006, the one having the absolute value closest to 0 is determined, and the adjustment count at that time is set to jb (S009).
Fdata (jb) is set to the advance amount f (S010). The above is the procedure for adjusting the advance angle in the present embodiment.

Note that the present invention is not limited to SPM, and can also be applied to an embedded magnet type motor (IPM). When using IPM, a target value of id is set for each rotation speed, and the advance amount f is adjusted so that id approaches the target value in the same manner as the above-described advance angle adjustment procedure.
In addition, when the above lead angle adjustment operation is implemented by software in the processor, since there is a sine function calculation in the coordinate conversion, originally, a high-cost processor equipped with a floating point arithmetic unit or the like is necessary. In the configuration of the present embodiment, since there are only six absolute phase information values for calculating the sine function, the sine function values corresponding to the respective absolute phase information values are stored in memory as data in advance. This eliminates the need for sine function calculation, and can be realized without problems even with a low-cost processor. Furthermore, in the coordinate conversion for the advance angle adjustment of the present embodiment, the adjustment result does not change even if the coefficient (the square root of 2) described in Equation 3 is omitted, so that the amount of calculation can be reduced.

  As described above, the periodic phase current value and the absolute phase are detected, and based on the direct current component obtained by coordinate conversion, the advance amount is optimally set in the sine wave drive, so that a plurality of devices having different characteristics can be obtained. On the other hand, since the optimum advance angle adjustment is performed for each individual and there is no need to wait until the maximum value of the sine wave waveform is detected, the adjustment time can be shortened.

Next, a second embodiment will be described.
FIG. 8 is a block diagram showing a configuration of the brushless motor driving apparatus according to the present embodiment. Only a configuration different from the first embodiment will be described.
The advance angle adjusting means 10 optimally sets the advance amount f based on the detected currents c1 and c2 and the absolute phase information b0.
Hereinafter, only the steps different from those of the first embodiment will be described in the description of the flowchart of the advance angle adjustment shown in FIG.
When a change in the absolute phase signal b0 is detected after S003 is completed, a current detection trigger cdt is output to the current detection means 5 so as to execute current detection. After the current detection by the current detection means 5 is completed, the detection currents c1 and c2 are received (S004).
Next, the coordinate transformation shown in Expression 3 is executed to obtain the reactive current id. At this time, iu and iv in Equation 3 are the values of the detection currents c1 and c2, and θ is a value obtained by converting the absolute phase information b0 input to the phase adjusting means 10 into an electrical angle by the formula 01. (S005). The above is the procedure for adjusting the advance angle in the present embodiment.

  As described above, the periodic phase current value and the absolute phase are detected, and based on the direct current component obtained by coordinate conversion, the advance amount is optimally set in the sine wave drive, so that a plurality of devices having different characteristics can be obtained. On the other hand, since the optimum advance angle adjustment is performed for each individual and there is no need to wait until the maximum value of the sine wave waveform is detected, the adjustment time can be shortened.

Next, a third embodiment will be described.
FIG. 9 is a block diagram showing the configuration of the brushless motor driving apparatus according to this embodiment. Only a configuration different from the above embodiments will be described. Note that position change detection means such as an encoder provided in the devices of the first and second embodiments is not necessary in this embodiment.
The speed detection means 6 detects all edges of the position signal a, measures the edge interval, and outputs a detection speed d0 based on the edge interval.
A PLL (Phase Locked Loop) 42 is a lock signal lk that is a binary signal indicating whether or not the PLL is locked in synchronization with the position signal a and absolute phase information b0 within one cycle of the position signal a. Is output. The configuration of the PLL 42 will be described later.

The advance angle adjusting means 10 and the advance angle adjusting operation are the same as those in the second embodiment.
When the lock signal lk is High, the drive signal generation unit 9 performs a sinusoidal drive operation as in the first embodiment. However, when the lock signal is low, the amplitude is normalized according to the logic of the hall signals Hu, Hv, and Hw constituting the position signal a according to Table 2, and the phase difference (64 [cnt]) of the electrical angle is 120 degrees. A three-phase rectangular wave waveform having a phase difference of 2) is generated. Thereafter, similarly to the sine wave drive, the drive voltage signal e is multiplied and then PWM modulated to output a switching element drive signal for the bridge circuit.
However, “H” and “L” in Table 2 indicate that the hall signals are “High” and “Low”, respectively. Further, “Z” indicates high impedance, and the switching elements drive signals in the phase “Z” are both set to Low in order to turn off the switching elements of the upper arm and the lower arm.

Next, the configuration and operation of the PLL 42 will be described with reference to FIGS. 10 and 11. FIG. 10 is a diagram showing the configuration of the PLL 42.
As shown in FIG. 11, the edge detection means 421 outputs a hole edge signal hg that detects all edges of the position signal a and generates a pulse signal.
The phase comparison means 422 compares the phase of an output signal from a frequency divider 425, which will be described later, with the Hall edge signal hg, and outputs a phase difference pd.
The loop filter 423 outputs a control voltage based on the phase difference pd so that the phase difference pd approaches zero.
The VCO 424 outputs a multiplied signal gp based on the control voltage. At this time, the gain of the VCO 424 is set so that the multiplied signal gp corresponds to 32 times the Hall edge signal hg.
The frequency divider 425 divides the multiplied signal gp by 1/32 in order to match the hall edge signal hg.
When the phase difference pd is within a predetermined range for a predetermined time, the lock determination unit 427 determines that the PLL is in a locked state and asserts the lock signal lk to High. Similarly, when the phase difference pd is out of the predetermined range for a predetermined time while the PLL is locked, the lock signal lk is set to Low. The determination of the lock state is performed in synchronization with the timing at which the pulse of the hall edge signal hg is input.

The counter means 426 repeatedly counts up the number of pulses of the input multiplied signal gp in the range of 0 to 191 [cnt], and outputs the count value as the absolute phase signal b0.
The count value loading unit 428 loads the count value into the counting unit 426 when the lock signal lk is asserted. The count value to be loaded is determined by the logic of the hall signals Hu, Hv, and Hw shown in FIG. 3 and Table 1.
The above is the configuration of the PLL 42, and the absolute phase information b0 is generated in synchronism with the position signal a and represents one cycle of the position signal a with a resolution of 192 [cnt].

As described above, the periodic phase current value and the absolute phase are detected, and based on the direct current component obtained by coordinate conversion, the advance amount is optimally set in the sine wave drive, so that a plurality of devices having different characteristics can be obtained. On the other hand, since the optimum advance angle adjustment is performed for each individual and there is no need to wait until the maximum value of the sine wave waveform is detected, the adjustment time can be shortened.
Furthermore, since absolute phase information is generated by the PLL, no detection means such as an encoder is required, and the manufacturing cost of the apparatus can be reduced.

DESCRIPTION OF SYMBOLS 1 Brushless motor 2 Bridge circuit 4 Phase generation means 5 Current detection means 6 Speed detection means 7 Speed comparison means 8 Speed control means 9 Drive signal generation means 10 Lead angle adjustment means 31 Hall IC as position detection means

JP 2007-028779 A

Claims (6)

A brushless motor driving device that rotates a rotor by passing a periodic current through an armature coil of a plurality of phases according to a rotational position of the rotor,
A bridge circuit configured by a switching element and a diode, and supplying a current to the armature coil;
Position detecting means for outputting a periodic position signal a in accordance with the position of the rotor;
Phase generating means for outputting absolute phase information b0 within one cycle of the position signal a in accordance with a signal based on the rotational position of the rotor;
Current detection means for outputting detection currents c1 and c2 of two phases according to the phase current flowing through the armature coil;
Speed detection means for outputting a detection speed d0 according to the rotation speed of the rotor;
Speed comparison means for comparing the target speed d1 of the rotor with the detected speed d0 and outputting a speed difference d2;
Speed control means for outputting a drive voltage signal e so that the rotational speed of the rotor follows the target speed in accordance with the speed difference d2.
Switching that drives a switching element of the bridge circuit according to the absolute phase information b0 and an advance amount f that gives a predetermined offset to the absolute phase information so that a sine wave current flows in the armature coil Drive signal generation means for outputting an element drive signal;
An advance angle adjusting means for converting the detected currents c1 and c2 into a DC detection current of a dq rotation coordinate system based on the position signal a and adjusting the advance amount f based on the DC detection current;
A brushless motor driving device comprising: A brushless motor driving device that rotates a rotor by passing a periodic current through an armature coil of a plurality of phases according to a rotational position of the rotor,
A bridge circuit configured by a switching element and a diode, and supplying a current to the armature coil;
Position detecting means for outputting a periodic position signal a according to the position of the rotor;
Phase generating means for outputting absolute phase information b0 within one cycle of the position signal a in accordance with a signal based on the rotational position of the rotor;
Current detection means for outputting detection currents c1 and c2 of two phases according to the phase current flowing through the armature coil;
Speed detection means for outputting a detection speed d0 according to the rotation speed of the rotor;
Speed comparison means for comparing the target speed d1 of the rotor with the detected speed d0 and outputting a speed difference d2;
Speed control means 8 for outputting a drive voltage signal e so that the rotational speed of the rotor follows the target speed in accordance with the speed difference d2,
Driving the switching element of the bridge circuit according to the absolute phase information b0 and the advance amount f giving a predetermined offset to the absolute phase information b0 so that a sine wave current flows through the armature coil; Drive signal generating means for outputting a switching element drive signal;
An advance angle adjusting means for converting the detected currents c1 and c2 into a DC detected current of a dq rotation coordinate system based on the absolute phase information b0 and adjusting the advance amount f based on the DC detected current;
A brushless motor driving device comprising: In the brushless motor drive device according to claim 1 or 2,
The brushless motor driving device, wherein the position detecting means is a Hall sensor. In the brushless motor drive device according to any one of claims 1 to 3,
The phase generation unit includes a counter that counts encoder output pulses synchronized with the rotational position of the rotor, and loads a predetermined value in accordance with the position signal a, A brushless motor driving device that outputs absolute position information b0. In the brushless motor drive device according to any one of claims 1 to 3,
The phase generation unit has a counter that counts the output pulses of the resolver synchronized with the rotational position of the rotor and loads a predetermined value according to the position signal a, A brushless motor driving device that outputs absolute position information b0. In the brushless motor drive device according to any one of claims 1 to 3,
The brushless motor driving device according to claim 1, wherein the phase detection means is composed of a PLL (Phase Locked Loop) that outputs absolute phase information b0 within one cycle of the position signal in phase with the position signal a.

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