JP2836199B2 - Commutatorless DC motor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a commutatorless DC motor, and more specifically, eliminates the need for a rotor position detecting element such as a Hall element for detecting the rotational position of a permanent magnet rotor. The present invention relates to a commutatorless DC motor.

2. Description of the Related Art A commutatorless DC motor has no mechanical contact compared to a DC motor with a brush, so it has a long life and little electrical noise.In recent years, industrial equipment and video / Widely applied to audio equipment.

Conventionally, most of the non-commutator DC motors of this type use a rotor position detecting element (for example, a Hall element) corresponding to a brush for switching an energized phase of a stator winding. However, the rotor position detection element itself is by no means inexpensive, and furthermore the complexity of adjusting the mounting position of the element,
Due to the increase in the number of wires, the commutatorless DC motor has a disadvantage that the cost is significantly increased as compared with the brushed DC motor.

In addition, since a rotor position detecting element must be mounted inside the motor, structural restrictions often occur. 2. Description of the Related Art In recent years, electric motors used for miniaturization of devices have been reduced in size and thickness, and there is no longer enough room for mounting position detecting elements such as Hall elements.

Therefore, some commutatorless DC motors without a rotor position detecting element such as a Hall element have been proposed.

One of them is a so-called half-wave drive type non-commutator DC motor which supplies a current to a stator winding only in one direction as disclosed in Japanese Patent Application Laid-Open No. 55-160980. This means that the next energized phase is determined by detecting the back electromotive force induced in the two stationary stator windings out of the three-phase stator windings, and the current is applied to the stator windings in only one direction. They are supplied sequentially.

Further, there is a so-called full-wave drive type non-commutator DC motor for supplying a current to a stator winding in both directions as disclosed in, for example, JP-A-62-260586. This is because when the rotation of the rotor rises and a back electromotive force is induced in the stator winding, the zero cross point of the back electromotive force is detected, and the output signal is delayed for a certain period of time by a mono-multi. Is determined. Hereinafter, the driving waveform will be described with reference to FIGS. 2 and 3.

FIG. 2 is a circuit diagram showing one embodiment of a stator winding power supply means constituting a non-commutator DC motor, and FIG. 3 is a signal waveform diagram of each part in a conventional example.

In FIG. 2, 27 is a permanent magnet rotor, 11, 12, and 13 are stator windings, and 21, 22, 23, 24, 25, and 26 are driving transistors, which are turned on and off by the stator. A current is supplied to the windings 11, 12, and 13. 21,22,23 of which are PNP
The transistors 24, 25 and 26 are NPN transistors. 20 is a power supply. In general, driving of the commutatorless motor is performed by applying a six-phase pulse signal obtained according to the rotational position of the rotor 27 to each base of the driving transistors 21, 26, 22, 24, 23, and 25. The waveforms of the six-phase pulse signals are shown in FIGS. However, the direction of the signal applied to the base of each transistor is in the direction in which current flows out to the PNP transistors 21, 22, and 23, and in the direction in which current flows in to the NPN transistors 24, 25, and 26. First, transistors 21 and 2
5 conducts and current flows through the stator windings 11 and 12. Next, the transistors 21 and 26 become conductive, and current flows through the stator windings 11 and 13. Such a phase switching operation is sequentially performed to rotate the permanent magnet rotor 27. At this time, currents shown in FIG. 3, j, k, and l are applied to the stator windings 11, 12, and 13 in both directions. When the rotor 27 is rotating, the stator windings 11, 12, 13
The voltages (back electromotive force) shown in FIGS. The six-phase pulse signals shown in FIGS. 7A to 7D correspond to the position signal of the rotor 27, and have the positional relationship shown in FIG. Note that the phases differ by 30 degrees. Therefore, in the prior art as disclosed in, for example, JP-A-62-260586, a zero-cross point of the back electromotive force induced in the stator winding is detected, and the output signal is delayed by a certain time by using a mono-multi. To determine the timing of energization. Therefore, the current flowing through the stator winding has a conduction width of approximately 120
The current becomes a rectangular wave having a degree (electric angle), and the current flowing through the stator winding is rapidly turned on and off.

Problems to be Solved by the Invention A commutatorless DC motor without a rotor position detecting element basically uses a back electromotive force induced in a stator winding to obtain a position required for phase switching of the stator winding. Creating a signal.

The non-commutator DC motor disclosed in Japanese Patent Application Laid-Open No. 55-160980 is a half-wave drive system that supplies current in only one direction of the stator winding, so that the drive circuit is simply configured. On the other hand, there is a problem that the utilization ratio of the stator winding is low, the efficiency is low, and the generated torque is small as compared with a full-wave drive type motor in which the current flowing through the stator winding flows in both directions.

Further, in the commutatorless DC motor disclosed in Japanese Patent Application Laid-Open No. 62-260586, the pulse generated at the zero cross point of the back electromotive force induced in the stator winding is delayed for a fixed time by a mono-multi. This is a method for determining the current-carrying phase, and the delay time is constant irrespective of the rotation speed of the electric motor.

Also, in the non-commutator DC motor shown in the prior art, the drive current flowing through the stator winding has a conduction waveform or a rectangular waveform having a substantially 120 degree (electrical angle). Therefore, a filter including a relatively large capacitor is actually required for the current-carrying terminal of the stator winding in order to reduce the spike-like voltage accompanying the switching. Also, the current flowing through the stator windings
Since it is turned off, it has a disadvantage that vibration and noise are easily generated during rotation, and the problem is that the tendency is more remarkable as the motor is used at higher speed.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a full-wave drive type non-commutator DC motor which does not require a rotor position detecting element and is configured so that current flowing through a stator winding flows in both directions.

Still another object of the present invention is to provide a commutatorless DC motor capable of arbitrarily changing the rotation speed of the motor.

Further, the present invention provides a non-commutator DC motor which does not require a filter circuit including a large capacitor as required for the non-commutator DC motor shown in the prior art, and has very little vibration and noise even at high speed rotation. It is intended to provide.

Means for Solving the Problems In order to achieve the above object, the present invention sets a zero-cross point of a back electromotive force generated in each of the plural-phase stator windings in accordance with a selection signal output from the selection signal generation means. Back electromotive force detecting means for detecting a pulse signal train in order and a pulse signal train output from the back electromotive force detecting means for dividing the pulse signal train to generate a plurality of phase pulses having the same frequency as the counter electromotive force of the stator winding A logic pulse generating means for generating a signal, and a switching means for switching an energized state of the stator winding in response to a multi-phase pulse signal output from the logic pulse generating means and a pulse signal train of the back electromotive force detecting means. A position signal generating means for generating a rotation position signal of the rotor; and a stator winding power supply means for energizing the stator winding based on the rotation position signal. Pulse generation means The detection timing of the zero-cross point of the back electromotive force and the fixed timing to be detected based on the multi-phase pulse signal output by the controller and the delay pulse of the pulse delay means for delaying the pulse signal train output from the back electromotive force detection means A position signal generating means for generating a sawtooth wave in synchronization with a pulse signal train output from the back electromotive force detecting means; Non-rectifying means comprising: signal synthesizing means for synthesizing a rotational position signal of a rotor based on a plurality of phase pulse signals output from the generating means and the sawtooth wave, to generate a trapezoidal wave rotational position signal. It is a child DC motor and solves the above-mentioned problem.

According to the present invention, the zero cross point of the back electromotive force induced in the stator winding is pulse-shaped and converted into a pulse signal train, and a rotor position signal is created based on the pulse signal train. Therefore, even if the rotation speed of the electric motor is changed, the energization phase of the stator winding to be energized next does not change. In addition, a selection circuit is added so that only the back electromotive force of the phase to be detected next is replaced with a pulse signal train from the state of conduction of the stator winding. And stable driving is always obtained.

Therefore, it can be easily applied to applications where the rotation speed needs to be changed, and the drive is performed when the rotation speed is changed as seen in the conventional non-commutator DC motor that does not require the rotor position detecting element. Is not unstable.

In addition, since only the zero-cross point of the back electromotive force induced in the stator winding is detected, the current flowing through the stator winding can flow in both directions without being affected by the drive current. A configuration of a driving type electric motor can be adopted. Therefore, a non-commutator DC motor with higher efficiency and higher torque than a half-wave drive type motor can be provided.

In addition, since the phase switching of the current applied to each phase of the stator winding is performed extremely smoothly, a relatively large capacitor for reducing a spike-like voltage associated with the phase switching as seen in the conventional example. It is not necessary to connect the filter circuit including to the current-carrying terminal of the stator winding.

Further, since the phase switching is performed smoothly without the current flowing through the stator winding being turned on / off sharply as in the conventional example, it is possible to drive the electric motor with very little vibration and noise.

Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of a commutatorless DC motor according to one embodiment of the present invention. In FIG. 1, 1
Is a back electromotive force detecting means to which the back electromotive force induced in the three-phase stator windings 11, 12, 13 and the selection signal output from the selection signal generating means 6 are input. The back electromotive force detection means 1 detects a zero cross point of the back electromotive force induced in the stator windings 11, 12, and 13 in a predetermined order according to the selection signal output from the selection signal generation means 6, and generates a pulse train m. Convert. This pulse train m
Indicates the zero-cross point of the three-phase back electromotive force. The pulse train m output from the back electromotive force detection means 1 is input to the logic pulse generation means 2 and the pulse delay means 3. Logic pulse generating means 2
Divides the pulse train m output from the back electromotive force detection means 1 and outputs six-phase pulses having the same frequency as the back electromotive force induced in the stator windings 11, 12, and 13. The pulse delay unit 3 first counts the period m of the input pulse train, delays the output pulse by a time approximately half of the counted period, and outputs it to the selection signal generation unit 6 as a delay pulse z. In the selection signal generating means 6, the delay pulse z and the logical pulse generating means 2
Then, a six-phase selection signal for determining the detection timing of the zero-cross point of the back electromotive force and the stator winding to be detected is output to the back electromotive force detection means from the six phase pulse signals from the above. on the other hand,
The six-phase pulse signal generated by the logical pulse generator 2 is input to the position signal generator 4 and converted into a rotation position signal of the rotor 27 based on the six-phase pulse signal and the pulse train m. This rotational position signal is input to the stator winding power supply means 5 in the form of a six-phase trapezoidal wave. The stator winding power supply means 5 sequentially supplies a drive current to each of the stator windings 11, 12, and 13 in both directions in accordance with the rotor position signal output from the position signal generation means 4.

The operation of the commutatorless DC motor of the present invention will be described in detail based on the embodiment configured as described above.

FIG. 4 is a signal waveform diagram of each part of one embodiment of the stator winding power supply means 5 constituting the non-commutator DC motor of the present invention.

In FIG. 4, a, b, and c are stator windings 11, 12, 1 respectively.
3 is a back electromotive force waveform induced in FIG. 6D to 6I show six-phase signals synthesized by the position signal generating means 4 and correspond to six-phase position signals obtained according to the rotational position of the rotor 27. This is a trapezoidal signal waveform unlike the rectangular signal waveforms shown in FIGS. 3d to i of the conventional example. Note that a method of obtaining the trapezoidal signal waveform is described in FIGS.
This will be described in detail in the position signal generating means described with reference to the drawing.

The six-phase position signals shown in FIGS. 4d to 4i are input to the respective bases of the driving transistors 21, 26, 22, 24, 23 and 25 shown in FIG. However, the direction of the signal applied to the base of each transistor is in the direction in which current flows out to the PNP transistors 21, 22, and 23, and in the direction in which current flows in to the NPN transistors 24, 25, and 26. Then, each transistor amplifies the added base current and a current proportional to each base current flows to each collector. As a result stator winding 1
The electric currents shown in FIGS. 4, j, k, and l are applied to 1, 12, and 13 in both directions. Such a phase switching operation is sequentially performed to rotate the permanent magnet rotor 27.

The operation of each unit of the embodiment of the present invention that performs such signal processing will be further described with reference to the drawings.

FIG. 5 is a circuit diagram of the back electromotive force detecting means 1 in one embodiment of the present invention shown in FIG.

5, 14, 15 and 16 are resistors, one of which is a stator winding 1
The terminals 1, 12, and 13 are connected to each other, and the other is commonly connected. 31, 32 and 33 are comparison circuits, whose input terminals (+) are connected to the terminals of the stator windings 11, 12, and 13, respectively, and whose input terminals (-) are commonly connected to resistors 14, 15, and 16. Points are connected. 34, 35 and 36 are inverter circuits,
Outputs 1, 32 and 33 are connected. 71,72,73,74,75,76
Is a switch, and one of the switches 71, 73, 75 is connected to the inverter circuits 36, 34, 35, respectively, and the switches 72, 74,
One of 76 is connected to the comparison circuits 32, 33, 31 respectively. The other of the switches 71, 72, 73, 74, 75, 76 is commonly connected, and serves as an output terminal of the back electromotive force detection means 1.

The operation of the back electromotive force detecting means shown in FIG. 5 will be described with reference to FIG.

Resistors 14, 15, and 16 in FIG. 5 are stator windings 11, 12, and 13, respectively.
Therefore, the same potential as the neutral point of the stator windings 11, 12, and 13 is obtained at the common connection point of the resistors 14, 15, and 16. Therefore, it is not necessary for the motor to draw a signal line from the neutral point of the stator winding. Stator winding
The back electromotive forces induced in 11, 12, and 13 are shown in Figs. 6a, b, and c, respectively.
Are input to the input terminals (+) of the comparators 31, 32, and 33 in FIG. 5, and the input terminal (-) is connected to the common connection point of the resistors 14, 15, and 16. The neutral point potential of the obtained stator winding is input. Therefore the comparator
Pulses obtained by shaping the back electromotive force a, b, c as shown in FIG. 6 are obtained at the output terminals 31, 32, 33. The pulse edges of the pulse waveforms u, v, w coincide with the zero cross points of the back electromotive forces a, b, c, respectively. In FIG. 6, t1, t2, t3, t4, t5, and t6 are six-phase signals output from the selection signal generating means 6 to the back electromotive force detecting means 1, and the rising edges thereof are the back electromotive forces a, b, and c.
5 shows the timing of the zero crossing point and the selection signal waveform delayed by 30 degrees in electrical angle. The switches 71, 72, 73, 74, 75 and 76 are turned on / off by these selection signals (signal "H").
Switch on, switch off with signal “L”).

As a result, the waveform shown in FIG. 6m is obtained from the common connection point of the switches 71, 72, 73, 74, 75 and 76, and the three-phase back electromotive force a,
A pulse train m in which the zero-cross point of b and c coincides with the rising edge of the pulse is output. That is, the back electromotive forces a, b,
A pulse is output at each zero-cross point of c, and back electromotive forces a, b, and c
Pulse train m 6 times (per 60 electrical degrees) per cycle
Is output. As described above, the detection timing and the stator winding are determined by the selection signal of the selection signal generation means 6, so that
Only the zero cross point of the back electromotive force generated in the stator winding to be detected can be accurately detected.

Next, the operation of the pulse delay unit 3 in one embodiment of the present invention will be described in detail.

FIG. 7 is a circuit configuration diagram of the pulse delay means 3 in one embodiment of the present invention shown in FIG. 1, and FIG. 8 is a signal waveform diagram of each portion of the electric motor during steady rotation.

In FIG. 7, 41 is the first counting means, and 42 is the second counting means.
Is a clock pulse generating means.
The first counting means 41 outputs a carry flag t when the counted value exceeds a predetermined value.
42 outputs a zero flag z when the count value becomes zero. The clock pulse generating means 44 generates two types of clock pulses ck and 2ck.
The clock pulse of 2ck (the clock frequency is twice ck) is input to the second counting means 42. Reference numeral 43 denotes a transfer unit to which a pulse train m output from the back electromotive force detection unit 1 is input, a first counting unit 41 receives a reset pulse r for resetting its count value, and a second counting unit 42 outputs a first pulse r. A load pulse s for loading the count value of the counting means 41 is output. The signal z forms a delay pulse.

The operation of the pulse delay means 3 shown in FIG. 7 will be described with reference to FIG. 8 when the permanent magnet rotor 27 is rotating normally. The first counting means 41 counts up the clock pulse ck until the reset pulse r output from the transfer means 43 is input. Since the reset pulse r has the same cycle as the pulse train m output from the back electromotive force generating means 1, the count value of the first counting means 41 is determined by counting the cycle of the pulse train m output from the back electromotive force detecting means 1. Become. FIG. 8p shows the count value in an analog manner. The count value p of the first counting means 41 is transferred to the second counting means 42 as an initial value at the timing of the load pulse s output from the transferring means 43. The second counting means 42 counts the count value p obtained by counting the period of the pulse train m by 2ck
Counts down with the clock of
The count value becomes zero at exactly the middle point of the pulse train (or the rising edge of the pulse m). Fig. 8 qa
Is shown analogously. Since the second counting means 42 is configured to output a zero flag when the count value is zero, the second counting means 42 outputs a delay pulse z as shown in FIG. 8z. The pulse train m is a pulse output from the back electromotive force detecting means 1. The rising edge of the pulse train m indicates the zero cross point of the back electromotive forces a, b, and c induced in the three-phase stator windings 11, 12, and 13. Therefore, the interval between the pulse trains s output at the rising edge of the pulse train m is equivalent to 60 electrical degrees. Therefore, z shown in FIG.
Is delayed by exactly 30 electrical degrees from the zero-cross point of the back electromotive forces a, b, and c, and is output to the selection signal generating means 6 as a delayed pulse. The phase relationship between the load pulse s and the reset pulse r is as shown in FIG. 8, and the reset pulse r is delayed from the load pulse s by the first counting means 41.
This is for surely transferring the count value to the second counting means 42. In FIG. 8, the pulse widths of the pulses s and r are shown large for convenience, but are assumed to be sufficiently narrower than the pulse period.

FIG. 9 is a circuit diagram of a main part of another embodiment of the pulse delay means 3 in one embodiment of the present invention shown in FIG. 1, and FIG. 10 is a signal waveform diagram of each part during steady rotation of the motor.

Components having the same functions as those in FIG. 5 are denoted by the same reference numerals, and redundant description will be omitted.

In FIG. 9, 41 is the first counting means, and 42 is the second counting means.
The first counting means is composed of an 8-bit digital counter, and the second counting means is composed of a 7-bit digital counter. The same clock ck is input to the first counting means 41 and the second counting means 42, respectively. The first counting means 41 counts up the clock ck, and the second counting means 42 counts down the clock ck. Reference numeral 45 denotes a switch transfer circuit composed of seven switches. The switch transfer circuit 45 is connected to a contact for a short time by a load pulse s of the transfer means 43 shown in FIG. 7, and changes the least significant bit of the count value of the first count means 41. The removed bits (7 bits in the example of FIG. 9) are transferred to the second counting means 42.

The operation of the pulse delay means shown in FIG. 9 will be described first with reference to FIG. 10 when the permanent magnet rotor 27 is rotating normally.

The count value p of the first counting means 41 is transferred to the second counting means 42 at the timing of the load pulse s output from the transferring means 43. However, since only the least significant bit of the first counting means 41 is discarded and transferred to the second counting means 42, as shown in FIG.
As the initial value of 42, a value that is 1/2 of the count value p of the first counting means 41 is given as the initial value. The second counting means 42 counts down p / 2 corresponding to a half of the count value obtained by counting the period of the pulse train s by the clock ck, so that the count value becomes zero at the intermediate point of the pulse train s. . Accordingly, the second counting means 42 outputs a delay pulse z as shown in FIG. Therefore, the rising edge of z shown in FIG. 10 is delayed by exactly 30 electrical degrees from the zero cross point of the back electromotive forces a, b, and c.

Although the frequency of the clock supplied to the first and second counting means is different in the embodiment of FIG. 7, the embodiment of FIG. 9 has an advantage that only one type of clock is required.

FIG. 11 is a circuit configuration diagram of another embodiment of the pulse delay means 3 in one embodiment of the present invention shown in FIG. 1, and FIG. 12 is a signal waveform diagram of each part during steady rotation of the rotor.

The components having the same functions as those in FIGS. 7 and 9 are denoted by the same reference numerals, and redundant description will be omitted.

In FIG. 11, reference numeral 61 denotes first up / down counting means, and 62 denotes second up / down counting means. First
The up / down counting means 61 and the second up / down counting means 62 have an up count input CU and a down count input CD, respectively. The first up / down counting means 61 and the second up / down counting means 62 output the zero flags za and zb respectively when the count value is reduced to zero. 63 is a clock switching circuit, and two types of clock pulses c generated by the clock generation means 44.
Whether k, 2ck (twice the clock frequency ck) is supplied to the up-count input CU or the down-count input CD is alternately switched according to the pulse m output from the back electromotive force detecting means 1. An OR circuit 64 is a zero flag z output by each of the first and second up / down counting means 61 and 62.
a and zb are input and a delay pulse z is output.

The operation of the pulse delay circuit shown in FIG. 11 will be described first with reference to FIG. 12 when the permanent magnet rotor 27 is rotating normally.

First, it is assumed that the switch of the clock switching circuit 63 is located at the contact a side shown in FIG. Then, the clock ck is supplied to the up-count input CU of the first up-down counting means 61, and the pulse m is supplied to the clock switching circuit.
First up / down counting means 61 until input to 63
Performs an up-count operation. Next, when the pulse m is input to the clock switching circuit 63, the switch of the clock switching circuit 63 is switched to the contact b side, and the first up / down counting means 61 switches to the down counting operation. At this time, the clock 2ck is input to the down count input of the first up / down count means 61. Accordingly, the count value obtained by counting up the cycle of the pulse train m is down-counted by the clock of 2ck, so that the count value becomes zero at exactly the middle point of the pulse train m. This is shown in FIG. 12 pa.
As a result, the first up / down counting means 61 outputs a zero flag za as shown in FIG. Similarly, the second up / down counting means 62 repeats the up / down counting operation as shown by pb in FIG. 12, and outputs a zero flag as shown in zb in FIG. Since the zero flags za and zb are generated alternately, a signal z as shown in FIG. 12 is output from the OR circuit 64, and the pulse delay means shown in FIG. 11 has rising edges of the back electromotive forces a, b and c. The delay pulse z delayed by exactly 30 electrical degrees from the zero-cross point is output.

7 and 9, the transfer means for transferring the count value of the first counting means to the second counting means is required. However, the transferring means is unnecessary in the embodiment of FIG. The switching circuit has the advantage that only the switching between the up-counting and down-counting operations needs to be performed.

FIG. 13 is a circuit configuration diagram of the logic pulse generating means 2 in one embodiment of the present invention shown in FIG. 1, and a signal waveform diagram of each part thereof is shown in FIG.

In FIG. 13, reference numeral 81 denotes a six-phase ring counter to which the pulse train m of the back electromotive force detecting means 1 is inputted, and six output terminals, p1, p2, p3, p4, p5, and p6 shown in FIG. Outputs the phase pulse signal. The pulse width of these pulse signals is an electrical angle
60 degrees. These six-phase pulse signals p1 to p6 are output to the position signal generating means 4 and the selection signal generating means 6 shown in FIG.

FIG. 15 is a circuit configuration diagram of the selection signal generating means 6 in one embodiment of the present invention shown in FIG. 1, and a signal waveform diagram of each part thereof is also shown in FIG.

In FIG. 15, reference numerals 91, 92, 93, 94, 95 and 96 denote D flip-flops, each of which has a clock terminal C to which a delayed pulse z output from the pulse delay means 3 is input, and a D pulse input terminal which generates a logical pulse. The six-phase pulse signals p1 to p6 output by the means 2 are input. As a result, from the Q output terminals of the D flip-flop, the six-phase pulse signals p1 to
p6 is output as six-phase signals t1 to t6 delayed by the pulse width of the delay pulse z. This is shown in FIG. These six-phase pulse signals t1 to t6 become the six-phase selection signals shown in FIG. 6, and have a pulse width of 60 degrees in electrical angle and are output to the back electromotive force detecting means 1.

FIG. 16 is a circuit diagram of the position signal generating means 4 in one embodiment of the present invention shown in FIG. 1, and FIG. 17 shows a signal waveform diagram of each part.

In FIG. 16, reference numeral 50 denotes a reset switch for discharging the charge stored in the charging / discharging capacitor 51, and reference numeral 51 denotes a charging switch for generating a sawtooth wave in synchronization with the pulse train m of the back electromotive force detecting means 1. A discharging capacitor 52 is a constant current source circuit for supplying a charging current to the charging / discharging capacitor 51, 54
Is a buffer amplifier whose input is connected to the capacitor 51. The capacitor 51, the switch 50, the constant current source circuit 52, and the buffer amplifier 54 constitute the sawtooth wave generating means 100. Five
Reference numeral 6 denotes an inverting amplifier to which the output of the buffer amplifier 54 is connected. Reference numeral 55 denotes a buffer amplifier to which an input is connected to a reference voltage source 53. Buffer amplifier 54, buffer amplifier 55
And outputs of the inverting amplifier 56 are signal synthesizing means 101, 102, 10
3,104,105,106. Note that the signal combining means 1
Since 01, 102, 103, 104, 105 and 106 have the same configuration, only the configuration of the signal synthesizing means 101 is shown. In the signal synthesizing means 101, switches 57, 58 and 59 are switches, one of which is connected to the buffer amplifiers 54 and 55 and the inverting amplifier 56, respectively, and the other of the switches 57, 58 and 59 is connected in common and connected to the resistor 61.
It is connected to the. The voltage signal obtained by the resistor 61 is converted into a current signal by a current conversion circuit 62,
Output.

Next, the operation of the position signal generating means 4 shown in FIG. 16 will be described with reference to the signal waveform diagrams of each part in FIG.

When the switch 50 of the sawtooth wave generating means 100 is open, a constant current is supplied to the capacitor 51 by the constant current circuit 52, and when the switch 50 is closed, the electric charge stored in the capacitor 51 is instantaneously discharged. . However, since the switch 50 is configured to close for a short time at the rising edge of the pulse m output from the back electromotive force detection means 1, the charge stored in the capacitor 51 is instantaneously discharged at the rising edge of the pulse m, Seventeenth from the sawtooth wave generating means 100
A sawtooth wave having the same phase as the pulse m as shown in FIG. St is obtained. Reference numeral 56 denotes an inverting amplifier, to which the output st of the buffer amplifier 54 is connected, so that a signal obtained by inverting st as shown in FIG. 17 stb is obtained from the output of the inverting amplifier 56. FIG. 17 sf shows the waveform of the reference voltage source 53, the magnitude of which is set equal to the peak value of the sawtooth wave st. The switches 57, 58, 59 constituting the signal synthesizing means 101 are turned on / off (switched on by a signal "H" and switched on by a signal "L") according to the pulse signals p1, p2, p3 output from the logical pulse generating means 2. (OFF), the outputs of the buffer amplifiers 54 and 55 and the inverting amplifier 56 are combined by the signal combining means 101, and the position signal waveform shown in FIG. 17d is obtained from the output terminal d.

When the switches 57, 58 and 59 are all turned off, the potential of the resistor 61 becomes equal to the ground potential. The combined voltage value obtained in the resistor 61 in this way is
It is converted into a current value (current sink) by 62, and a rotation position signal waveform shown in FIG. 17 is output from the output terminal d.

Hereinafter, similarly, the signal synthesizing means 102, 103, 104, 105, 106
Pulse signals (p2, p3, p4), (p3, p
4, p5), (p4, p5, p6), (p5, p6, p1) and (p6, p1, p2) output position signals e, f, g, h, i. FIG. 17 d to i
Is a position signal of the rotor 27 and is input to the stator winding power supply means 5 in FIG.

As is clear from the above description, in the non-commutator motor of the present invention, the back electromotive force detecting means 1 detects the zero cross points of the back electromotive forces a, b, and c induced in the stator windings 11, 12, and 13. Detected and converted to a conversion pulse m, the logic pulse generating means 2 receives this conversion pulse m and generates six-phase pulse signals p1 to p6. The six-phase pulse signals p1 to p6 are input to the position signal synthesizing means 4 and are changed into rotor position signals as shown in FIGS. And finally, the power supply means 5 applies the stator windings 11, 12, 13 according to the rotor position signals di to i in FIGS.
The drive currents as shown by k and l are sequentially supplied in both directions, so that the permanent magnet rotor 27 is rotated. The converted pulse m of the back electromotive force detecting means 1 is delayed by the pulse delaying means 3 by an electrical angle of 30 degrees and converted into a delayed pulse z. The six-phase pulse signals p1 to p6 are six-phase selection signals t1 to t6 delayed by the selection signal generating means 6 by the pulse width of the delay pulse z.
And input to the back electromotive force detection means 1.

Therefore, the non-commutator motor of the present invention can constitute a full-wave drive type motor that allows current flowing in the stator winding to flow in both directions without providing a rotor position detecting element such as a Hall element.

In the pulse delay means according to the present invention, in the embodiment of FIG. 7, the clock frequency input to the second count means has been described as twice the clock frequency input to the first count means. It may be double.
In the embodiment of FIG. 10 in the pulse delay means according to the present invention, the value transferred as the initial value to the second count means at the time of steady rotation was selected to be 1/2, but the value was not equal to an integer. It may be one. In the pulse delay means according to the present invention, in one embodiment of FIG. 12, the clock frequency input to one of the up-count input terminal and the down-count input terminal is the clock frequency input to the other input terminal. Although described as being twice the frequency, it is needless to say that an integer multiple can be used.

The back electromotive force detecting means 1 according to the present invention uses three commonly connected resistors to detect the neutral point potential of the stator winding as shown in FIG. Needless to say, it is also possible to directly draw out the signal line from the neutral point of the stator winding of the motor and use it. Further, in the embodiment, the stator winding is limited to the three-phase motor having the Y connection, but the number of phases is not limited to three, and may be any number. Further, the commutatorless motor of the present invention can be applied to a motor in which the stator windings are connected by Δ.

Effect of the Invention Since the present invention is configured as described above,
The following effects are obtained.

Since the non-commutator DC motor of the present invention detects only the zero cross point of the back electromotive force induced in the stator winding by the back electromotive force detecting means, a rotor position detecting element such as a Hall element is unnecessary. In spite of this, it is possible to easily configure a full-wave drive type motor that supplies current flowing through the stator windings in both directions. Therefore, compared with the half-wave drive system in which current is supplied to only one direction of the stator winding, a motor having a higher utilization rate of the stator winding, high efficiency, and high torque can be provided.

Further, since a rotor position detecting element such as a conventional non-commutator motor is unnecessary, the complexity of adjusting the mounting position of the element and the number of wires are reduced, and the cost is greatly reduced.

Furthermore, since there is no need to mount a rotor position detecting element inside the motor, the motor can be made ultra-small and ultra-thin without any structural restrictions.

Further, the non-commutator DC motor of the present invention, the detection timing of the zero cross point of the back electromotive force and the stator winding to be detected, the count value of the time between the zero cross point of the back electromotive force and each stator winding , And the zero-cross point is accurately detected in a predetermined order, so that there is no malfunction of the phase switching due to the erroneous detection of the zero-cross point of the back electromotive force, and stable driving can always be obtained. Therefore, the present invention can be applied to an application in which the number of rotations of the electric motor needs to be arbitrarily changed.

Furthermore, in the non-commutator DC motor of the present invention, the phase switching of the current supplied to each stator winding is performed very smoothly,
Since the current flowing through the stator winding is not turned on / off abruptly, induction noise is significantly reduced. As a result, it is not necessary to connect a filter circuit including a relatively large capacitor to the current-carrying terminal of the stator winding in order to reduce a spike-like voltage caused by the phase switching. A commutator DC motor can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of one embodiment of a non-commutator DC motor of the present invention, and FIG. FIG. 3 is a circuit configuration diagram showing an example, FIG. 3 is a signal waveform diagram of each part of a stator winding power supply unit in a conventional example, and FIG. 4 is a signal waveform diagram of each unit of a stator winding power supply unit in one embodiment of the present invention. FIG. 5 is a circuit diagram showing one embodiment of the back electromotive force detecting means constituting one embodiment of the present invention, FIG. 6 is a signal waveform diagram of each part of FIG. 5, and FIG. FIG. 8 is a circuit configuration diagram showing an embodiment of a pulse delay means constituting the embodiment, FIG. 8 is a signal waveform diagram of each part when steady rotation is performed in FIG. 7, and FIG. 9 is a pulse constituting an embodiment of the present invention. FIG. 10 is a circuit diagram of a main part of another embodiment of the delay means. FIG. 11 is a circuit configuration diagram showing another embodiment of the pulse delay means constituting one embodiment of the present invention, and FIG. 12 is a signal waveform diagram of each part when steady rotation is performed in FIG. FIG. 13 is a circuit diagram showing one embodiment of a logic pulse generating means constituting one embodiment of the present invention.
FIG. 14 is a signal waveform diagram for explaining the operation of one embodiment of the logic pulse generating means constituting one embodiment of the present invention and the selection signal generating means constituting one embodiment of the present invention, and FIG. FIG. 16 is a circuit configuration diagram showing one embodiment of the selection signal generation means constituting one embodiment. FIG. 16 is a circuit configuration diagram showing one embodiment of the position signal generation means constituting one embodiment of the present invention. Is the 16th
FIG. 3 is a signal waveform diagram for explaining the operation of FIG. 1 ... back electromotive force detection means, 2 ... logic pulse generation means,
3 ... pulse delay means, 4 ... position signal generation means, 5 ...
... stator winding power supply means, 6 ... selection signal generation means,
11, 12, 13 ... stator windings, 41 ... first counting means,
42 second counting means, 61 first up / down counting means, 62 second up / down counting means.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-3-230791 (JP, A) JP-A-1-91690 (JP, A) JP-A-1-122387 (JP, A) JP-A-1- 148092 (JP, A) JP-A-2-51389 (JP, A) Patent 2751579 (JP, B2) (58) Fields investigated (Int. Cl. ⁶ , DB name) H02P ^6/ 00-6/24

Claims (5)

(57) [Claims] A counter electromotive force for generating a pulse signal train by detecting a zero cross point of a counter electromotive force generated in each of a plurality of phase stator windings in a predetermined order according to a selection signal output from a selection signal generating means. Power detection means, logic pulse generation means for dividing the pulse signal train output from the back electromotive force detection means to generate a multi-phase pulse signal having the same frequency as the back electromotive force of the stator winding, A rotational position signal of a rotor for switching an energized state of the stator winding in response to a multi-phase pulse signal output from the logical pulse generating means and a pulse signal train of the back electromotive force detecting means. And a stator winding power supply means for energizing a stator winding based on the rotational position signal, wherein the selection signal generating means comprises a logic pulse generating means. Outputs Based on the multi-phase pulse signal and the delay pulse of the pulse delay means for delaying the pulse signal train output from the back electromotive force detection means, the detection timing of the zero cross point of the back electromotive force and the detection timing Outputting a selection signal for determining the stator winding, the position signal generating means periodically generating a sawtooth wave in a pulse signal train output from the back electromotive force detecting means, and a sawtooth wave generating means; Signal synthesizing means for synthesizing a rotational position signal of a rotor based on the multi-phase pulse signal output by the logical pulse generating means and the sawtooth wave, and generating a trapezoidal rotational position signal. No commutator DC motor. The pulse delay means counts the period of the pulse signal train output from the back electromotive force detection means, and outputs a delayed pulse delayed by a time proportional or substantially proportional to the counted period. The commutatorless DC motor according to claim 1, wherein: 3. The pulse delaying means includes: first counting means for counting a period of a pulse signal train output by the back electromotive force detecting means; and a count value of the first counting means transferred to a second counting means. Transfer means, and second count means for outputting a delay pulse delayed from the transferred count value by a time proportional to or substantially proportional to the cycle of the pulse signal train;
2. A non-commutator DC motor according to claim 1, further comprising clock generation means for inputting a clock to said first and second counting means. 4. The apparatus according to claim 3, wherein said transfer means transfers half the count value of said first count means to said second count means. No commutator DC motor. 5. The non-rectifier DC motor according to claim 3, wherein the clock frequency input to the second counting means is twice the clock frequency input to the first counting means. .