JPH07241095A - Driver for brushless motor - Google Patents

Abstract

PURPOSE:To reduce power consumption by reducing the iron loss of a motor while furthermore reducing the copper loss and the saturation of a switching element by decreasing the motor current. CONSTITUTION:A driver for a brushless motor 1 including a rotor 4 having a permanent magnet and a stator 3 having windings 2U, 2V, 2W for a plurality of phases comprises transistors 10-15 for conducting the windings 2U, 2V, 2W sequentially at a timing corresponding to the position of the rotor 4, and a control circuit 32 for turning the transistors 10-15 ON/OFF to feed the winding 2U, 2V, 2W with a PWM sine wave voltage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless motor driving device for driving and controlling a brushless motor having a rotor having permanent magnets and a stator having windings of a plurality of phases.

[0002]

2. Description of the Related Art An example of a brushless motor drive device of this type will be described with reference to FIGS. First, in FIG. 9, the brushless motor 1 has three-phase windings 2U,
It is composed of a stator 3 having 2V and 2W and a rotor 4 having a permanent magnet. Brushless motor 1
Includes three position detecting elements 5U, which are, for example, Hall ICs, as position detecting means for detecting the rotational position of the rotor 4.
5V and 5W are provided.

The drive circuit 6 for energizing and driving the respective windings 2U, 2V, 2W has its input terminals 7a, 7b.
Are connected to the positive and negative terminals of the DC power supply 8. still,
A capacitor 9 is connected between the positive terminal and the negative terminal of the DC power supply 8. The drive circuit 6 has input terminals 7a and 7b.
Six switching elements, for example, NPN type transistors 10 to 12 and 13 to 15 are connected in a three-phase bridge connection therebetween. Each transistor 1
Free wheel diodes 16 to 21 are connected in parallel to 0 to 15, respectively. Also, the transistor 1
The common connection point between 0 and the transistor 13 is connected to the output terminal 22, and the common connection point between the transistor 11 and the transistor 14 is connected to the output terminal 23.
A common connection point between the transistor 15 and the transistor 15 is connected to the output terminal 24.

The output terminal 22 is connected to one end of the winding 2U of the brushless motor 1, and the output terminal 23 is connected to the winding 2U.
The output terminal 24 is connected to one end of the winding 2W. The other ends of the three-phase windings 2U, 2V, and 2W are commonly connected. The bases of the six transistors 10 to 15 of the drive circuit 6 are the control circuit 25.
Is connected to the control signal Su from the control circuit 25,
On / off control is performed in response to Sv, Sw, Sx, Sy, and Sz. The control circuit 25 receives the detection signals Hu, Hv, and Hw from the three position detection elements 5U, 5V, and 5W, and also receives the speed command signal AC from the outside.

In this case, when the control circuit 25 receives the speed command signal AC, the three position detecting elements 5U, 5V, 5W are received.
Detection signals Hu, Hv, Hw from FIG.
(C)), control signals Su, Sv, Sw, Sx, Sy, Sz as shown in FIGS. 10D to 10I are generated, and these control signals Su, Sv, Sw, Sx, S
y and Sz are six transistors 10 to 15 of the drive circuit 6.
To control ON / OFF of the transistors 10 to 15. As a result, the output terminals 22, 23, 2 of the drive circuit 6 are
4 shows the output voltage V as shown in FIGS.
u, Vv, Vw are output, and these output voltages Vu, V
v, Vw are three-phase windings 2U, 2 of the brushless motor 1
By supplying V, 2W, brushless motor 1
The rotor 4 is driven to rotate. The control circuit 25 is configured to variably control the rotation speed of the brushless motor 1 by, for example, pulse width modulation (PWM) control so that the brushless motor 1 rotates at the rotation speed instructed by the speed command signal AC. .

[0006]

The present inventor has considered using the above-mentioned brushless motor 1 as a running motor for an electric vehicle. In this case, since the charging capacity of the battery in the electric vehicle is fixed, the loss of the motor should be minimized and the motor and its drive unit should be miniaturized in order to maximize the mileage. is necessary. Therefore, the inventor of the present invention examined the loss generated in the brushless motor 1 having the above-described conventional configuration.

First, when the waveforms of the currents flowing through the windings 2U, 2V, 2W of the stator 3 of the brushless motor 1 were examined, it was found that they were rectangular waves. Specifically, the current waveform of the current Iu flowing through the winding 2U is shown in FIG.
It shows in (b). Incidentally, FIG. 11A shows a voltage waveform of the line voltage Vuv supplied between the windings 2U and 2V. Then, such a rectangular wave-shaped current is applied to the windings 2U, 2V, 2W.
It was found that a large iron loss occurs due to the harmonic current component contained in the rectangular wave-shaped current. Further, since the total power factor of the motor voltage and current becomes low and a large amount of current flows, the copper loss generated in the motor increases and the saturation loss of the transistors 10 to 15 (switching element) of the drive circuit 6 also increases. It turns out that power consumption will increase. For this reason, when the brushless motor 1 and the drive device for the brushless motor 1 configured as described above are used in an electric vehicle, there is a drawback in that the traveling distance per charge of the electric vehicle is shortened.

Further, in the above-mentioned conventional structure, since the heat generation in the transistors 10 to 15 of the drive circuit 6 becomes large,
A large radiator is needed. In addition, brushless motor 1
Since the loss that occurs in 1 is large, it is necessary to increase the volume of the motor in order to improve heat dissipation. In this case as well, the motor and its driving device are large-sized and the weight is increased, so that there is a drawback that the traveling distance per charge of the electric vehicle is shortened.

Therefore, an object of the present invention is to provide a drive device for a brushless motor which can reduce iron loss, and also reduce motor current to reduce copper loss and saturation loss of switching elements. It is in.

[0010]

SUMMARY OF THE INVENTION A brushless motor driving device of the present invention is a brushless motor driving device for driving and controlling a brushless motor including a rotor having permanent magnets and a stator having windings of a plurality of phases. At
A control is provided that includes a switching element for sequentially energizing each of the windings at energizing timings corresponding to the position of the rotor, and controls on and off of the switching element so as to apply a voltage of a sinusoidal pulse width modulation waveform to each of the windings. It is characterized by having a means.

In this configuration, the control means includes position detecting means for detecting the position of the rotor, triangular wave signal generating means for generating a triangular wave signal, and pulse width modulation based on the detection signal from the position detecting means. For generating a pulse width modulated signal by comparing the triangular wave signal from the triangular wave signal generating means with the modulated signal from the modulated signal generating means. And controlling the switching element to be turned on and off based on the pulse width modulation signal from the comparison means by the control means so as to give a voltage of a sinusoidal pulse width modulation waveform to each of the windings. Is also preferable.

Further, in this case, when the modulation signal generated from the modulation signal generating means is e (θ), e (θ) = k · sin θ (where θ is an angle, k is greater than 0 and less than 1) It is conceivable that a voltage having a sinusoidal pulse width modulation waveform is applied to each of the windings.

When the modulation signal generated from the modulation signal generating means is e (θ), e (θ) = k · sin θ + l · sin3θ (where θ is an angle, k and l are larger than 0 and 1 The following constants are set so that the voltage obtained by adding the voltage of the pulse width modulation waveform including the harmonic of 3 times the motor operating frequency to the voltage of the sinusoidal pulse width modulation waveform is applied to each winding. It is also preferable to be configured to feed the wire.

Further, when the modulation signal generated from the modulation signal generating means is e (θ), when 0 ≦ θ <2π / 3, e (θ) = k · sin θ 2π / 3 ≦ θ <4π / When 3, e (θ) = k · sin
(Θ-π / 3) When 4π / 3 ≦ θ <2π, set so that e (θ) = 0 (where θ is an angle and k is a constant greater than 0 and 1 or less). Therefore, it is even more preferable to apply a voltage obtained by adding the voltage of the pulse width modulation waveform including the harmonic of 3 times the motor operating frequency to the voltage of the sinusoidal pulse width modulation waveform to each of the windings.

On the other hand, the motor voltage detecting means for detecting the motor phase voltage and the motor current detecting means for detecting the motor current are provided, and the modulation signal generating means is provided so that the current value at the zero cross point of the modulation signal becomes zero. It is also conceivable to provide a phase correction means for correcting the output phase of the modulation signal from the motor, and to adjust the output phase of the pulse width modulation signal so that the motor phase voltage matches the fundamental wave phase of the motor current. Further, in this case, it is preferable to adjust the output phase of the pulse width modulation signal at each zero cross point of the motor phase voltage of each phase.

At the zero-cross point where the motor phase voltage changes from negative to positive, the output phase of the pulse width modulation signal is adjusted to advance when the current value is positive, and delayed when the current value is negative. At the zero-cross point where the phase voltage changes from positive to negative, the output phase of the pulse width modulation signal is advanced when the current value is negative,
When it is positive, it may be possible to adjust it so that it is delayed.

Furthermore, it is more preferable to replace the triangular wave signal generating means with a sine wave signal generating means for generating a sine wave signal or a sawtooth wave signal generating means for generating a sawtooth wave signal. Is.

[0018]

The present inventor has confirmed by experiments that the waveform of the induced voltage induced in each winding of the stator is a sine wave when the rotor of the brushless motor is rotated. Therefore, it is understood that the iron loss of the motor can be extremely reduced by applying a voltage having the same waveform as the induced voltage, that is, a sinusoidal voltage to each winding of the stator. The present invention has been made paying attention to this point.

That is, according to the above-mentioned means, since the switching element is controlled to be turned on / off by the control means and the voltage of the sinusoidal pulse width modulation waveform is applied to each winding of the stator, the iron loss of the motor is greatly increased. Can be reduced. In this case, the control means specifically includes a position detection means for detecting the position of the rotor, a triangular wave signal generation means for generating a triangular wave signal, and a pulse width modulation based on the detection signal from the position detection means. Comparing means comprising a modulation signal generating means for generating a modulation signal, and a comparing means for comparing the triangular wave signal from the triangular wave signal generating means with the modulation signal from the modulating signal generating means to generate a pulse width modulated signal. If the switching element is controlled to be turned on / off based on the pulse width modulation signal from, it is possible to apply a voltage having a sinusoidal pulse width modulation waveform to each winding.

If a voltage obtained by adding a voltage of a pulse width modulation waveform containing a harmonic of 3 times the motor operating frequency to a voltage of a sinusoidal pulse width modulation waveform is applied to each winding of the stator. The fundamental wave component can be increased, and the number of times of switching of the switching element in pulse width modulation can be reduced accordingly. Therefore, with this configuration, switching loss can be reduced.

On the other hand, the motor voltage detecting means for detecting the motor phase voltage and the motor current detecting means for detecting the motor current are provided, and the modulation signal generating means is provided so that the current value at the zero cross point of the modulation signal becomes zero. The phase correction means for correcting the output phase of the modulation signal from the motor is provided, and the output phase of the pulse width modulation signal is adjusted so that the motor phase voltage matches the fundamental wave phase of the motor current. The current can be reduced, and the copper loss and the saturation loss of the switching element can be reduced.
In this case, if the output phase of the pulse width modulation signal is adjusted at each zero-cross point of the motor phase voltage of each phase, a more excellent effect can be obtained.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a drive device of a brushless motor used as a running motor of an electric vehicle will be described below with reference to FIGS. 1 to 6. The same parts as those in the conventional configuration (see FIG. 9) are designated by the same reference numerals.

That is, in FIG. 1, the brushless motor 1
The drive circuit 6 for energizing and driving the respective windings 2U, 2V, 2W of the stator 3 of FIG.
It is constructed by connecting 0 to 12 and 13 to 15 in a three-phase bridge. The input terminals 7a and 7b of the drive circuit 6 are connected to the positive and negative terminals of the DC power supply 8. A capacitor 9 is connected between the positive terminal and the negative terminal of the DC power supply 8. In this case, the DC power supply 8 is a battery mounted on the electric vehicle. The free wheel diode 16 is connected to each of the transistors 10 to 15 of the driving circuit 5.
21 are connected in parallel.

The common connection point between the transistors 10 and 13, the common connection point between the transistors 11 and 14, and the common connection point between the transistors 12 and 15 are the output terminal 22, the output terminal 23, and the output terminal, respectively. It is connected to 24. The output terminals 22, 23, 24 are connected to one end of the winding 2U, one end of the winding 2V, and one end of the winding 2W of the brushless motor 1, respectively. The other ends of the three-phase windings 2U, 2V, and 2W are commonly connected.

Here, the brushless motor 1 is provided with, for example, an encoder 31 as a position detecting means for detecting the rotational position of the rotor 4, instead of the three position detecting elements 5U, 5V, 5W. The encoder 31 detects the rotational position of the rotor 4 and detects detection signals Ha and Hb (see FIG. 2).
(See (a) and (b)).

On the other hand, the six transistors 1 of the drive circuit 6
0 to 15 are configured to be on / off controlled by a control circuit 32 instead of the control circuit 25. The control circuit 32 constitutes a control means, and the control circuit 32 will be described below. The control circuit 32 includes the counter circuit 3
3, a memory circuit 34, a triangular wave signal generating circuit such as a triangular wave signal generating circuit 35, comparison circuits such as comparing circuits 36U, 36V and 36W, and a power factor correction circuit 37. The counter circuit 33 includes the encoder 3
When the detection signals Ha and Hb from 1 are received, as shown in FIG. 2C, the count value CN is incremented at the rising of each detection signal Ha and Hb.
The counter circuit 33 is configured to reset the count value CN to zero when receiving the reset signal Rs from the power factor correction circuit 37.

Further, the memory circuit 34 is the counter circuit 3
In response to the count value CN from 3 and an accelerator signal (speed command signal AC in this case) output from an accelerator (not shown) of the electric vehicle, for example, sinusoidal modulation signals Mu, Mv, Mw (FIG. 3). (D) shows the modulation signal Mu) to the comparison circuits 36U, 36V, 36W, and the zero-cross signal Mz to the power factor correction circuit 37. In addition to the zero-cross signal Mz, the power factor correction circuit 37 includes a current detection signal Iu from a current detector 38 provided on a connection line that connects the output terminal 22 of the drive circuit 6 and the winding 2U of the stator 3. In response to this, the reset signal Rs is output. The current detector 38 constitutes motor current detecting means, and the power factor correction circuit 37 constitutes phase correcting means.

Further, the triangular wave signal generating circuit 35 generates a triangular wave signal Bs (see FIGS. 3 (d) and 4 (a)) having a predetermined constant period, and compares the signal Bs with the comparing circuit 36U, It is configured to be applied to 36V and 36W.
The comparison circuits 36U, 36V, and 36W compare the modulation signals Mu, Mv, and Mw from the memory circuit 34 with the triangular wave signal Bs from the triangular wave signal generation circuit 35, and control signals Su, Sv, Sw, and Sx. , Sy, Sz (Fig. 3
(E) and (f) show control signals Su and Sx), and generate these control signals Su, Sv, Sw, Sx, Sy, and S.
z is applied to the bases of the transistors 10 to 15 of the drive circuit 6.

Next, the operation of the above configuration will be described with reference to FIGS.
Refer also to the explanation. When the brushless motor 1 is rotationally driven, the counter circuit 33 causes the encoder 3 to operate.
When receiving the detection signals Ha and Hb from 1 (see FIGS. 2A and 2B), the count value C as shown in FIG.
N is counting up. In this case, when the counter circuit 33 receives the reset signal Rs from the power factor correction circuit 37, specifically, the times ta and t shown in FIG.
At b, the count value CN is reset to zero.
Then, the memory circuit 34 outputs the modulation signals Mu, Mv, Mw as shown in FIG. 3D according to the count value CN from the counter circuit 33. Although not shown, the modulation signals Mv and Mw are signals that are 120 degrees and 240 degrees out of phase with the modulation signal Mu, respectively. Here, the memory circuit 34 is configured to change the amplitudes of the modulation signals Mu, Mv, Mw according to the speed command signal (accelerator command signal) AC.

Now, the three comparison circuits 36U, 36V and 3
The comparison circuit 36U, which is one of the 6W, is connected to the memory circuit 34
3 and the triangular wave signal Bs from the triangular wave signal generation circuit 35 are compared to generate control signals Su and Sx as shown in FIGS. 3E and 3F (in this case, the control signal Sx Is an inverted signal of the control signal Sx), and these control signals Su and Sx are supplied to the transistor 10 of the drive circuit 6.
And 13 bases. As a result, the transistors 10 and 13 are turned on while the control signals Su and Sx are at the high level and turned off during the low level.

Further, the remaining two comparison circuits 36V and 36V
Similarly, W is also the modulation signal M from the memory circuit 34.
v, Mw and the triangular wave signal B from the triangular wave signal generation circuit 35
s is compared to generate control signals Sv, Sw and Sy, Sz, and these control signals Sv, Sw and Sy, Sz are given to the bases of the transistors 11, 12, 14 and 15 of the drive circuit 6. As a result, the transistors 11, 1
2 and 14, 15 are control signals Sv, Sw and Sy, S
The z is turned on during the high level and turned off during the low level.

Then, as described above, the transistor 1
The drive circuit 6 is controlled by controlling 0 to 15 on and off.
4 (b), (c),
Output voltages Vu, Vv, Vw as shown in (d) are output, and these output voltages Vu, Vv, Vw are supplied to the windings 2U, 2V, 2W of the stator 3, respectively. As a result, the rotor 4 of the brushless motor 1 is rotationally driven.

In this case, the voltages Vu, Vv, Vw supplied to the windings 2U, 2V, 2W are voltages having a sinusoidal pulse width modulation waveform. In addition, at this time, the line voltage Vuv of the brushless motor 1 is as shown in FIG. 4E, which is a voltage having a sinusoidal pulse width modulation waveform. At this time, the waveform of the current Iu flowing through the winding 2U is
As shown in FIG. 4 (f), a sinusoidal waveform is obtained.
As a result, the iron loss of the brushless motor 1 can be significantly reduced as compared with the conventional configuration (see FIGS. 9 to 11).

Further, the power factor correction circuit 37 uses the modulation signal M
When receiving the zero-cross signal Mz of u, Mv, and Mw,
The output timing of the reset signal Rs is determined according to the state of the current detection signal Iu from the current detector 38. Specifically, as shown in FIGS. 5B and 5E, when the current detection signal Iu from the current detector 38 is negative when the zero cross signal Mz is received from the memory circuit 34, as shown in FIG. When the reset signal Rs is output before the count value CN changes to zero after one cycle, as shown in FIG. 6C, and when the zero cross signal Mz is received, as shown in FIGS. 6B and 6E. When the current detection signal Iu is positive, the output of the reset signal Rs is repeated after the count value CN has changed to zero, as shown in FIG. 6C. As a result, the phases of the motor voltage and the current become the same, so that the power factor is improved and the motor current can be reduced. Therefore, the copper loss of the brushless motor 1 can be reduced and the saturation loss of the transistors 10 to 15 of the drive circuit 6 can be reduced.

In the above embodiment, the modulation signals Mu, M
Although sine waves are used as v and Mw, the present invention is not limited to this, and modulation signals having waveforms as shown in FIGS. 7B and 7C may be used, for example. In this case, in particular, FIG.
When the modulated signal shown in (c) is used, a control signal,
The waveforms of the output voltage and the motor current are as shown in FIGS. 8A to 8H, the fundamental wave voltage is increased, and the number of switching times of the transistors 10 to 15 can be significantly reduced. Switching loss can be reduced.

Further, in the above embodiment, the triangular wave signal generation circuit 35 for generating the triangular wave signal Bs as the carrier signal.
However, instead of this, a sine wave signal generating circuit (means) for generating a sine wave signal or a sawtooth wave signal generating circuit (means) for generating a sawtooth wave signal may be used. Further, in the above embodiment, the comparison circuit 36U,
The control signals Su, Sv, Sw, S are compared by comparing the modulation signals Mu, Mv, Mw with the triangular wave signal Bs by 36V, 36W.
Although x, Sy, and Sz are output, the control signals Su, Sv, Sw, and S are directly output from the memory circuit 34.
It is also a preferable configuration to output x, Sy, and Sz.

On the other hand, in the above embodiment, the power factor correction of the voltage and the current is performed once / cycle, but the present invention is not limited to this. For example, the current is output to all (three) outputs of the drive circuit 6. A configuration in which a detector is attached and power factor correction is performed at the zero-cross points of the modulation signals of each phase, that is, a configuration in which power factor correction is performed 6 times / cycle may be adopted. In this case, it is possible to use only two current detectors instead of three current detectors, and obtain the remaining current value from the difference between the two current detection values.

In the above embodiment, the zero crossing point of the motor phase voltage is judged (detected) from the zero crossing points of the modulation signals Mu, Mv, Mw, and as a result, the force at the zero crossing point of the motor phase voltage is detected. The rate is corrected. At the zero-cross point where the motor phase voltage changes from minus to plus, the output phase of the pulse width modulation signal is advanced when the current value is positive and delayed when it is negative, as described in the above embodiment. It was adjusted. On the other hand, at the zero-cross point where the motor phase voltage changes from positive to negative, the output phase of the pulse width modulation signal is advanced when the current value is negative, and adjusted so that it is delayed when the current value is positive. It is preferable.

In the above embodiment, the encoder 31 is provided as the position detecting means for detecting the position of the rotor 4. However, the present invention is not limited to this. For example, three position detecting elements including Hall elements are used. You can provide it,
Further, the position detection signal may be generated by detecting the induced voltage generated in the stator winding.

[0040]

As is apparent from the above description, the present invention is configured to control the switching elements to be turned on and off by the control means so as to apply the voltage of the sinusoidal pulse width modulation waveform to each winding of the stator. It has an excellent effect that the iron loss of the brushless motor can be greatly reduced. Then, in this case, the control means outputs the position detecting means for detecting the position of the rotor, the triangular wave signal generating means for generating the triangular wave signal, and the modulation signal for pulse width modulation based on the detection signal from the position detecting means. The modulation signal generating means for generating and the comparing means for generating the pulse width modulated signal by comparing the triangular wave signal from the triangular wave signal generating means with the modulation signal from the modulating signal generating means are provided. By controlling the switching element to be turned on and off based on the width modulation signal, it is possible to apply a voltage having a sinusoidal pulse width modulation waveform to each winding.

Further, if a voltage obtained by adding a voltage of a pulse width modulation waveform containing a harmonic of 3 times the motor operating frequency to a voltage of a sinusoidal pulse width modulation waveform is applied to each winding of the stator. The fundamental wave component can be increased, and the number of times of switching of the switching element in pulse width modulation can be reduced accordingly. As a result, switching loss can be reduced.

On the other hand, there is provided a phase correction means for correcting the output phase of the modulation signal from the modulation signal generation means so that the current value at the zero cross point of the modulation signal becomes zero, and the motor phase voltage is the fundamental wave phase of the motor current. Since the output phase of the pulse width modulation signal is adjusted so as to match with, the motor current can be reduced and the copper loss and the saturation loss of the switching element can be reduced. In this case, if the configuration is such that the output phase of the pulse width modulation signal is adjusted at each zero crossing point of the motor phase voltage (modulation signal) of each phase, a further excellent effect can be obtained.

[Brief description of drawings]

FIG. 1 is an electric circuit diagram showing an embodiment of the present invention.

FIG. 2 is a time chart of detection signals Ha and Hb from an encoder and a count value CN of a counter circuit.

FIG. 3 is a time chart of detection signals Ha and Hb, count value CN, modulation signal Mu, triangular wave signal Bs, control signals Su and Sx.

FIG. 4 is a modulation signal Mu, a triangular wave signal Bs, an output voltage V
Time chart of u, Vv, Vw, line voltage Vuv, current Iu

FIG. 5 is a time chart of a count value CN, a zero cross signal Mz, a reset signal Rs, a modulation signal Mu, and a current Iu at the time of power factor correction.

FIG. 6 is a count value CN at the time of power factor correction in different states, a zero cross signal Mz, a reset signal Rs, a modulation signal Mu,
Current Iu time chart

FIG. 7 is a waveform diagram showing a modulation signal of a modified example.

FIG. 8 is a time chart of a modulation signal Mu, a triangular wave signal Bs, control signals Su and Sx, output voltages Vu, Vv, Vw, a line voltage Vuv, and a current Iu in a modified example.

9 is a view corresponding to FIG. 1 showing a conventional configuration.

FIG. 10: Position detection signals Hu, Hv, Hw, control signal S
u, Sv, Sw, Sx, Sy, Sz, output voltage Vu, V
v, Vw time chart

FIG. 11 is a time chart of a line voltage Vuv and a current Iu.

[Explanation of symbols]

1 is a brushless motor, 2U, 2V, 2W are windings, 3 is a stator, 4 is a rotor, 5U, 5V and 5W are position detecting elements (position detecting means), 6 is a drive circuit, 7a and 7b are input terminals, 8 Is a DC power source, 10, 11, 12, 13, 14,
15 is a transistor (switching element), 22, 2
3, 24 are output terminals, 31 is an encoder (position detecting means), 32 is a control circuit (control means), 33 is a counter circuit, 34 is a memory circuit, 35 is a triangular wave signal generating circuit (triangular wave signal generating means), 36U, 36V and 36W are comparison circuits (comparison means), 37 is a power factor correction circuit (phase correction means), and 38 is a current detector (motor current detection means).

Front page continuation (72) Inventor Hideki Jonoguchi 991, Anada-cho, Seto City, Aichi Prefecture Toshiba Corporation Aichi Factory

Claims (9)

[Claims] 1. A brushless motor driving device for driving and controlling a brushless motor, comprising: a rotor having a permanent magnet; and a stator having windings of a plurality of phases, wherein each winding is electrified corresponding to a position of the rotor. Driving a brushless motor, comprising: a switching element for sequentially energizing at timings; and a control means for on / off controlling the switching element so as to apply a voltage having a sinusoidal pulse width modulation waveform to each winding. apparatus. 2. The control means for detecting the position of the rotor, a triangular wave signal generating means for generating a triangular wave signal, and pulse width modulation based on the detection signal from the position detecting means. A modulation signal generating means for generating a modulation signal; and a comparing means for comparing the triangular wave signal from the triangular wave signal generating means with the modulation signal from the modulation signal generating means to generate a pulse width modulated signal, 2. A voltage having a sinusoidal pulse width modulation waveform is applied to each of the windings by controlling ON / OFF of the switching element based on the pulse width modulation signal from the means. Brushless motor drive. 3. When the modulation signal generated from the modulation signal generating means is e (θ), e (θ) = k · sin θ (where θ is an angle, k is a constant greater than 0 and 1 or less). The drive device for the brushless motor according to claim 2, wherein a voltage having a sinusoidal pulse width modulation waveform is applied to each of the windings by setting such that 4. When the modulation signal generated from the modulation signal generating means is e (θ), e (θ) = k · sin θ + l · sin 3θ (where θ is an angle and k and l are greater than 0 and By setting so that it is a constant of 1 or less), the voltage obtained by adding the voltage of the pulse width modulation waveform including the harmonic of 3 times the motor operating frequency to the voltage of the sinusoidal pulse width modulation waveform The brushless motor drive device according to claim 2, wherein the drive device is provided to each winding. 5. When the modulation signal generated from the modulation signal generating means is e (θ), when 0 ≦ θ <2π / 3, e (θ) = k · sin θ 2π / 3 ≦ θ <4π When / 3, e (θ) = k · sin
(Θ-π / 3) When 4π / 3 ≦ θ <2π, set so that e (θ) = 0 (where θ is an angle and k is a constant greater than 0 and 1 or less). Accordingly, a voltage obtained by adding a voltage having a pulse width modulation waveform including a harmonic of 3 times the motor operating frequency to a voltage having a sinusoidal pulse width modulation waveform is applied to each of the windings. Item 2. A brushless motor drive device according to item 2. 6. A motor voltage detecting means for detecting a motor phase voltage, a motor current detecting means for detecting a motor current, and a modulation signal generating means so that a current value at a zero cross point of the modulation signal becomes zero. 3. The brushless according to claim 2, further comprising: a phase correction unit that corrects an output phase of the signal, and adjusting the output phase of the pulse width modulation signal so that the motor phase voltage matches the fundamental wave phase of the motor current. Motor drive device. 7. The brushless motor drive device according to claim 6, wherein the output phase of the pulse width modulation signal is adjusted at each zero-cross point of the motor phase voltage of each phase. 8. A zero-cross point at which the motor phase voltage changes from negative to positive is adjusted so that the output phase of the pulse width modulation signal is advanced when the current value is positive and delayed when the current value is negative. The zero-cross point at which the phase voltage changes from positive to negative is adjusted so that the output phase of the pulse width modulation signal is advanced when the current value is negative and delayed when the current value is positive. Brushless motor drive device. 9. A sine wave signal generating means for generating a sine wave signal or a saw tooth wave signal generating means for generating a saw tooth wave signal is provided in place of the triangular wave signal generating means. The brushless motor driving device described.