JPS61150695A - Drive device of dc commutatorless motor - Google Patents

Abstract

PURPOSE:To reduce a vibration or a noise by bringing the rectified added value obtained from 3 magnetoelectric transducers into coincidence with a command signal, and responding the output of a power supply circuit to the combined value of the absolute values of the outputs of the transducers. CONSTITUTION:The outputs of magnetoelectric transducers 1-3 are buffer- amplified by amplifiers 21-23 to obtain a signal iH, which is subtracted by subtractors 31-33 to produce a signal iP, which is amplified by power supply circuits 101-103, and supplied to drive coils 4-6. A signal iP is added by an adder 40 to produce a signal, which is input to an error amplifier 50 to regulate the amplification factors of the amplifiers 21-23 so that the difference from the command signal iT from a command signal generator 80 becomes zero. The combined value ia of the signal ir added by an adder 60 from the absolute value from the signal iH, a signal iC subtracted by the command value iT, and the output currents of power supply circuits 101-103 is amplified by an error amplifier 70 to regulate the power supply circuit 101-103 to become ic=ia. Thus, even if the transducers are irregular, a product of low vibration and low noise can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a drive device for a DC commutatorless motor.

Conventional technology In recent years, the current-carrying phase of the armature is controlled by a semiconductor (for example, a transistor) in response to the output of a rotor position detector (for example, a Hall element).
A DC commutatorless motor configured to switch sequentially at
It is applied to audio equipment and video equipment.

Normally, a DC non-commutated motor requires one rotor position detector and one armature energization control circuit for each phase, and increasing the number of motor phases will complicate the configuration of the control circuit itself. , it is expensive and large, making it impractical. Therefore, a two-phase or three-phase armature is generally employed, and as a result, there is usually a torque ripple of 15 to 204 pp. Correspondingly, rotational irregularities of DC non-commutator motors have increased, causing an increase in wow and flutter in audio and video devices.

Hall elements are often used as rotor position detectors in recent DC non-commutated motors, but as is well known, Hall elements have large variations in sensitivity. Many attempts have been made to absorb the variations using circuit technology and also to correct the torque ripple of DC non-commutated motors.

Japanese Unexamined Patent Publication No. 59-35585 (hereinafter abbreviated as Document 1) discloses a typical technique using three Hall elements as a rotor position detector. Although a detailed explanation of the configuration of the drive circuit will be omitted, the key point of its operation is that, as shown in the above-mentioned document 1, the switching timing of the coil is adjusted to the timing when the output of the Hall element becomes zero. The present invention is resistant to variations in Hall element output, and cancels torque ripple by partially modulating the current supplied to the coil in response to a modulation signal synchronized with the rotation of the motor.

Problems to be Solved by the Invention However, according to the configuration of the drive device shown in Document 1, the circuit operates based on the zero output of the Hall element, so that it is resistant to variations in the output of the Hall element. 1. Since the energization control to the armature coil is an on/off control, a filter containing a relatively large capacitor is required at the energizing terminal to the armature coil to reduce or eliminate the spike voltage that occurs when the energized coil is switched. Become.

Furthermore, since the current flowing through the armature coil is abruptly turned on and off, it also has the disadvantage that it tends to generate vibrations and noise.

In view of the above problems, the present invention uses a Hall element as a rotor position detector, but it is resistant to variations in sensitivity of the Hall element output and does not require a filter as required in the drive device shown in Document 1. The present invention provides a motor drive device with low vibration, low noise, and low torque ripple.

Means for Solving the Problems In order to solve the above problems, the drive device for a DC non-coherent motor of the present invention includes a magnetoelectric conversion element that detects a magnetic field, a buffer amplifier that amplifies each output of the magnetoelectric conversion element, a plurality of subtraction circuits that combine the differences between the outputs of the buffer amplifiers;
a rectifying and adding circuit for synthesizing the sum of positive or negative parts of each output of the subtracting circuit; a command signal generation circuit for generating a torque command signal for the motor; a first error amplifier that adjusts the amplification degree of the buffer amplifier or the input supply voltage of the plurality of magnetoelectric conversion elements; and an absolute value addition circuit that converts each output of the buffer amplifier into an absolute value and adds it. a power supply circuit that supplies current to the armature coils of multiple phases with the output of the subtraction circuit; a current detection means that detects the current supplied to the armature coils of the multiple phases; The second error amplifier adjusts the amplification degree of the power supply circuit so that the supplied current responds to a composite signal obtained by combining the command signal and the output of the absolute value addition circuit.

Effect The present invention uses a plurality of magnetoelectric transducers as a rotor position detector with the above-described configuration, and has a circuit configuration that is resistant to variations in the sensitivity of the output of the magnetoelectric transducers and resistant to offsets, resulting in low vibration and low noise. The present invention aims to realize a drive device for a DC non-commutator motor with low torque ripple.

Embodiment Hereinafter, a driving device for a DC commutatorless motor according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 2 shows a perspective view of the main parts of a preferred Mome to which the present invention is applied. In the figure, 7 is a rotation axis. A soft iron disc 8 as a back yoke is fixed to the rotating shaft 7, and a disc-shaped rotor magnet 9 is attached to the lower surface of the disc 8.
are fixed to form the rotor. 4, 5.6 is a three-phase armature coil, which is a soft iron type stator iron plate 1.
It is fixed on the surface of o with adhesive or the like. A bearing 11 is fixed to the stator iron plate 10 so as to be at the center of the three-phase armature coils 4, 5.6, and rotatably supports the rotating shaft 7. A Hall element 1.2.3 is used as a rotor position detector, and is arranged at the center of each armature coil so as to be able to detect the magnetic field of the disc-shaped rotor magnet 9.

FIG. 1 shows a circuit configuration diagram of a motor drive device in an embodiment of the present invention. In the figure, 120 is a DC power supply, which serves as an input supply voltage source for three Hall elements 1°2.3. 21, 22, 23 are each Hall element 1.2.3
In this embodiment, the differential output of each Hall element is converted into a non-current IH1 and a non-current IH1, and a current IH3 is output.

The buffer amplifiers 21, 22, and 23 are each configured to provide three current outputs (current magnitudes are the same). 31.32.33 is a subtraction circuit,
The output of the buffer amplifier 21 and the output current 'H*p'H2 of the buffer amplifier 22 are input to the subtraction circuit 31 and subtracted, and a current 'P1 (='H1-'H2) is outputted. The output currents lH2 and lH3 of the buffer circuits 22 and 23 are inputted to the subtraction circuit 32 and subtracted, resulting in 'P2 (
='H2-'H3) current is output.

Similarly, the subtraction circuit 33 contains the output current 'H3?' of the buffer circuits 23 and 21. iH1 is input and subtracted to 'P3 (=
A current of iH3-'H1) is output.

It is assumed that the subtraction circuits 31, 32, and 33 are each configured to obtain two output currents (assuming the magnitudes are the same). And one current output 'P1 t'P2t'P
3 are input to the power supply circuits 101, 102 and 103, respectively, and the other current output is input to the rectifying and adding circuit 4o. The rectifying and adding circuit 40 is a diode 41.4
2, 43 and a resistor 44, the subtraction circuit 31.
By energizing only the positive portion of the output current 'P1t'P2s'P3 of 32 and 33 to the resistor 44, the rectification and addition result is output as a voltage. Reference numeral 80 denotes a command signal generation circuit which outputs a current IT proportional to the input ET from two output terminals. One current output IT is energized by the resistor 82, and after being converted into a voltage, the first
is input to the error amplifier 60. First error amplifier 60
The rectification and addition result of the rectification and addition circuit 40 is inputted to the other input terminal of , and the amplification degree of the puff 71 circuit 21.degree. 22.23 is adjusted so that the two input voltages match. 60
is an absolute value addition circuit, and includes buffer circuits 21, 22 .
23 current output 'H1*'H2t'Hs is input. 4゜6.6 is a three-phase armature coil connected in a star shape, and connected to power supply circuits 101, 102, 103, respectively.
connected to the output side of the 114 is a DC power supply that determines the input operating point of the power supply circuits 101, 102, 103;
, 32, 33 is provided to convert the current output iP1°'P2j'P3 into a voltage.

90 is a current detection resistor, 3-phase armature coil 4°5.6
A current detection means is configured to detect the current flowing into the current in the form of voltage. 70 is a second error amplifier, 2
A composite signal obtained by combining the detected voltage of the current detection resistor 9o, the output current of the command signal generation circuit 80, and the output current of the absolute value addition circuit SO is input to the two input terminals. In this embodiment, the current output IT of the command signal generation circuit and the current output 1K of the absolute value addition circuit are subtracted, and the resultant current to(=i
7-L,) is created and converted into a voltage by a resistor 71.

The output of the second error amplifier 7o is connected to the three power supply circuits 10
1.102, 103, the second error amplifier 70
The power supply circuits 101 and 102
, 103 are adjusted.

The operation of the DC commutatorless motor drive device configured as described above will be described with reference to FIGS. 3, 4, and 6.

Figure 3 shows the rotation angle θ of the rotor expressed in electrical angles.
It shows the waveforms of each part of the drive device shown in the figure. Fig. 3 Differential output voltage waveforms of Ad Hall elements 1, 2, and 3 eH19
eH29eH3. Regarding FIG. 3, assuming that the rising point of the differential output voltage eH1 from o)) to positive is θ=0°, the differential output voltages eH2veH3 are each delayed in phase by 1200 degrees. In FIG. 3A, it is assumed that there is no sensitivity variation or offset in the differential outputs of the Hall elements 1, 2, 3.

In general, in permanent magnet rotor type motors, the permanent magnets are magnetized with trapezoidal waves in consideration of high motor efficiency and mass production, so the differential output voltage of the Hall element that detects the magnetic field has a high order It even contains harmonic components. In Figure 3A, each of the 3rd, 5th, and 7th components is 1246 times larger than the fundamental wave.
An example containing %1265% gα part is shown.

Figure 3B shows the current output waveform '1 (1j 'L!?'7) of the buffer amplifiers 21, 22, 23, and Figure 3C shows the current output waveform 'P1t'P of the subtraction circuits 31, 32, 33.
2t'Pa. Regarding FIG. 1, since the control loop is constituted by the buffer amplifiers 21, 22° 23, the subtracting circuits 31, 32, 33, the rectifying and adding circuit 40, and the first error amplifier 60, the subtracting Each current output 'P1j' of circuits 31, 32゜33
As shown in FIG. 3C, the peak value of P2t'P3 is a constant value proportional to the motor command signal (waveform in FIG. 3E). By the operation of the control loop described above, the Hall element 1
．． Even when sensitivity variations and offsets exist in 2.3, the amplification degree of the buffer amplifier is adjusted, and each current output 'P11 'p2t' of the subtracting circuits 31, 32, 33
P3 is taken as the positive direction. Buffer circuit 21, 22゜2
Between each current output iH1, iH2, lH3 of 3 and the current output -r of the absolute value addition circuit 6o, 'r=IHl 1+l
'H21+I)i31 relationship exists. FIG. 3E shows the current output of the command signal generating circuit 8o, which has a magnitude proportional to the motor command signal. FIG. 3F shows the current i flowing into the resistor 71, and the relationship between the current output lT of the command signal generation circuit 8o and the current output ir of the absolute value addition circuit 60 is i, = i7-i r. There is. FIG. 3F includes ripples of the sixth order.

In FIG. 1, power supply circuits 101, 102, 103
and a detection resistor 9o that converts the magnitude of the current flowing into the armature coils 4, 5.6 into voltage, and the voltage generated in the detection resistor 90 and the voltage generated in the resistor 71 are input to the two input terminals. , power supply circuit 101.102,1 with output
A control loop is constituted by a second error amplifier 70 connected to adjust the amplification degree of 03.

The operation of the above control loop will be explained using FIGS. 4 and 6.

FIG. 4 shows a waveform diagram when the output of the absolute value addition circuit 60 is in an open state.

FIG. 4A shows three-phase generated voltage waveforms e1, e2, . This shows e3. Regarding FIG. 4, the rising point from 0 to positive for the generated voltage waveforms e2. The phases of e3 are delayed by 1200. Also, the differential output voltage waveforms of Hall elements 1, 2, and 3 eH1゜eH2, eH3 are emitted! 1!
Pressure waveform e1. e2tes ha" The phases are advanced by soo each. In Fig. 4A, the generated voltage waveforms e1, e2, and e induced in the three-phase armature coils 4,5,6.
The wave height values of 3 are all assumed to be equal. In practice, the shape of the armature coil.

Since the arrangement is mechanically determined with high precision, this assumption is generally satisfied in reality. Also, the armature coil usually has a number of
Since the 0-turn winding is performed with a certain winding width, the generated voltage waveform induced in the armature coil contains relatively few harmonic components, and in FIG. The following harmonic components are 7.1%, o, and 4% compared to the fundamental wave.
An example is shown below.

Figure 4B shows the current A flowing through the armature coils 4, 5.6.
1*12113 is shown. Power supply circuit 1
01,102. '+03 input side has subtraction circuits 31 and 3.
2.33 current output 'P1t'P2t'P3 is input, and on the other hand, the amplification degree of the power supply circuits 101, 102° 103 is maintained at a constant value according to the command signal because the output of the absolute value addition circuit 60 is in an open state. Therefore, the input is linearly amplified as it is and the current waveform 11゜12.13 that is energized to the three-phase armature coils 4, 5.6 is the current output waveform of the subtraction circuit 31.32.33 'P1t 'P2 t 'The waveform is similar to P3. Also, the current output 'P of the subtraction circuit 31, 32, 33
i *'P2v'P3 outputs the difference between two sets of output currents 'H1, 'H2y'Hs of three sets of buffer amplifiers 21, 22, and 23 that amplify each output of three sets of Hall elements. Because it is 'P1"P2+1P3"('H1-1)12)"
The relationship 1H3)+(IH3-1H1)20 always holds true. Therefore, the power supply circuit 10
The output current 11.1.102, 103 is linearly amplified and applied to the three-phase armature coils 4,5.6. i2
．． The relationship 11+12+13=0 also holds true between i3. In other words, the sum of the currents flowing into the three conducive armature coils is equal to the sum of the currents flowing out from the three conducive armature coils, and there is no problem in the star-connected three conducive armature coils as shown in this embodiment. It becomes possible to supply current. Note that the sum of the currents flowing into the three-phase armature coils is a constant value proportional to the command signal.

FIG. 4C shows a torque waveform generated by the motor when a current as shown in FIG. 4B is applied to the three electric armature coils of the motor. The torque generated by the motor is shown in Figure 4A.
The generated voltage e1. induced in the armature coil shown in e
2. e3 and the current i1. which is applied to the armature coil shown in FIG. 4B. i2. The sum of the products of i3 (e11
It is proportional to 1+e2・12 pigeon-13). In Fig. 4C, the maximum values of generated torque are θ=30°, 90', 15
It appears at the points of 0°, 210°, etc., and the minimum value is θ=O', 600, 120'.

It appears at the point 18o0, and the main component of the torque ripple is 6
It is a harmonic component.

In this embodiment, when the output side of the absolute value addition circuit 60 is opened, the power supply circuit 101.
When the amplification degrees of 102 and 103 are adjusted, the magnitude of torque ripple will be approximately 1496 p-p.

In order to suppress this torque ripple, the sum of the currents flowing into the three armature coils should not be controlled to be constant, but should be controlled so that the ripple component of the torque waveform shown in Fig. 4C has an opposite phase relationship. Moreover, it is sufficient to modulate the above-mentioned current sum with the same ripple rate.

In the drive device for the DC non-commutator motor shown in Fig. 1, Fig. 4C
In order to suppress the torque ripple shown in FIG. As shown in Figure 3, the output current 1r of the absolute value addition circuit 6o has the same phase as the ripple component of the torque waveform in Figure 4C, so in order to reverse the phase, the output current 1r is constant in proportion to the command signal. Output current ir from current i 7 (Fig. 4E)
By subtracting the modulation signal 1° (Fig. 4F)
is being created. Furthermore, the two input terminals of the second error amplifier 70 are connected to the detection voltage of a current detection resistor 9° that converts the sum of currents flowing into the three induction armature coils of the motor into a voltage value, and the output of the command signal generation circuit 80. A modulation signal io that synthesizes the difference between the current IT and the output current 1□ of the absolute value addition circuit 6o
The amplification degree of the power supply circuits 101, 102 and 103 is adjusted so that both inputs of the second error amplifier 7o match. The torque ripple is suppressed by making the ripple rate of the modulation signal 1c equal to the ripple rate of the torque waveform shown in FIG. 4C.

Note that the above modulated signal i. In the DC non-commutator motor drive device shown in Fig. 1, the ripple rate of
It is possible to arbitrarily determine the resistance ratio with a resistance ratio of 4.

In this embodiment, torque ripple is minimized by setting the resistance value of the resistor 82 to 0.36 times the resistance value of the resistor 44.

By the way, if the content of harmonics contained in the differential output pressure waveform of the Hall element and the generated voltage waveform induced in the armature coil is different from the above case, the resistor 44 and the resistor 82 should be adjusted appropriately. Torque ripple can be minimized by determining the ratio of resistance values.

However, it is not necessary to perform this determination work for each motor having the same structure. This is because, in motors having the same structure, the content of harmonics in the differential output voltage waveform of the Hall element and the generated voltage waveform induced in the armature coil is considered to be approximately the same.

FIG. 5 shows the sum of the currents flowing into the three-phase armature coils of the motor in the configuration shown in FIG. 1 as the modulation signal i. FIG. 10 shows a waveform diagram when ripples in the torque waveform are suppressed by modulating the torque. Figure 5A shows the three-phase power generation waveform e induced in the three-phase armature coils 4 and 5.6.
1. e2. This shows e3. Figure 5B shows the sum of the currents flowing into the three-phase armature coils of the motor as a modulation signal i.
. This figure shows current waveforms 11 and 12tla applied to the three-phase armature coils 4 and 5°6 when modulated by . FIG. 5C shows a torque waveform generated by the motor when a current as shown in FIG. 6B is applied to the three-phase armature coil of the motor.

In this example, the main component of the torque ripple is the 12th fire component, and the magnitude of the torque ripple is 2.8 chips p - p
has been suppressed to.

Note that in the embodiment of FIG. 1, the first error amplifier 60
The outputs of are connected to buffer amplifiers 21, 22, and 23,
Although the amplification degree of the buffer amplifiers 21, 22.23 is adjusted in this embodiment, the input supply voltage of the Hall element 1.2.3 may be directly controlled by the output of the first error amplifier 6o.

Effects of the Invention As described above, the present invention includes a plurality of magnetoelectric transducers arranged on a stator to detect the magnetic field generated by rotor magnets, a buffer amplifier that amplifies each output of the magnetoelectric transducer, and a buffer amplifier. A plurality of subtracting circuits that synthesize the differences between the outputs of the amplifiers, a rectifying and adding circuit that synthesizes the sum of the positive or negative portions of the respective outputs of the subtracting circuits, and a command signal generation circuit that generates a torque command signal for the motor. and a first error amplifier that adjusts the amplification degree of the buffer amplifier or the input supply voltage of the plurality of magnetoelectric conversion elements so that the output of the rectifying and adding circuit matches the command signal; an absolute value addition circuit that converts each output into an absolute value and adds it; a power supply circuit that supplies current to the armature coils of multiple phases with the output of the subtraction circuit; Amplification of the power supply circuit is adjusted such that the current detection means detects the current and the current supplied to the armature coils of the plurality of phases responds to a composite signal obtained by combining the command signal and the output of the absolute value addition circuit. By providing the second error amplifier, multiple magnetoelectric transducers are used as the rotor position detector, but the circuit structure is resistant to variations in sensitivity of the magnetoelectric transducer output and resistant to offset, resulting in low vibration and noise. , provides a drive device for a DC non-commutator motor with low torque ripple.

[Brief explanation of the drawing]

FIG. 1 is a circuit configuration diagram of a drive device for a DC non-commutator motor according to an embodiment of the present invention, FIG. 2 is a perspective view of a main part of a motor suitable for applying the present invention, and FIG. 3 is a diagram. 4 and 5 are signal waveform diagrams for explaining the operation of the DC commutatorless motor drive device of the present invention. 1.2, 3... Hall element, 21, 22, 23
...Buffer amplifier, 31, . 32.33...
... Subtraction circuit, 40 ... Rectification addition circuit, 6
0... Absolute value addition circuit, 60... First
error amplifier, 70... second error amplifier, 1
01.102,103...Power supply circuit, 4,
5, 6... Armature coil. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Figure 4 Figure 5

Claims (2)

[Claims] (1) A plurality of magnetoelectric transducers arranged on the stator to detect the magnetic field generated by the rotor magnet, a buffer amplifier that amplifies each output of the magnetoelectric transducer, and a difference between the outputs of the buffer amplifiers is synthesized. a rectifying and adding circuit that synthesizes the sum of positive or negative parts of the respective outputs of the subtracting circuits; a command signal generating circuit that generates a motor torque command signal; and an output of the rectifying and adding circuit. a first error amplifier that adjusts the amplification degree of the buffer amplifier or the input supply voltage of the plurality of magnetoelectric conversion elements so that the output voltage matches the command signal; and a first error amplifier that converts each output of the buffer amplifier into an absolute value. an absolute value addition circuit for adding, a power supply circuit for supplying current to the armature coils of multiple phases with the output of the subtraction circuit, current detection means for detecting the current supplied to the armature coils for the multiple phases; A second error amplifier is provided for adjusting the amplification degree of the power supply circuit so that the current supplied to the armature coils of multiple phases responds to a composite signal obtained by combining the command signal and the output of the absolute value addition circuit. A drive device for a DC non-commutator motor. (2) The drive device for a DC non-commutator motor according to claim 1, wherein the composite signal is synthesized by subtracting the command signal and the output of the absolute value adding circuit.