JPS61135381A - Brushless motor drive device - Google Patents

Abstract

PURPOSE:To stably operate a motor at a time of switching-over by increasing a signal from rotating magnetic field generating means and a power source voltage by a synchronizing signal of the prescribed frequency within a low voltage, detecting the rotation of an induced voltage signal and then generating a signals of a switching command. CONSTITUTION:A brushless motor 3 having a magnet rotor 5 is rotated by controlling the energization of an armature winding 4 by semiconductor switching group 2. When started by starting command means 12, a period signal of the prescribed frequency is input to rotating magnetic field generating means 9 to form 3-phase synchronizing signals 9-U-W phases, and the group 2 is controlled through switching means 11 and controlling means 12. Further, the drive power source 1 of the motor 3 is increased within a low voltage to forcibly rotate a magnet rotor 5. Thus, the means 11 is switched by the means 10, the position detection signal of the rotor 5 is input from comparator group 7 to the means 12 to normally rotate the motor 3.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a brushless motor, and in particular detects the relative position between a magnet rotor and an armature winding by an induced voltage induced in the armature winding, and starts the motor. This invention relates to a brushless motor for stable rotation.

2. Description of the Related Art Conventionally, this type of brushless motor drive device has a configuration as shown in FIG. This configuration was created in the 1980s.
This is an example described in Japanese Patent Publication No. 6519 and Japanese Patent Publication No. 59-36520, and has a three-phase configuration.

For convenience, a three-phase example will be used for explanation below.

That is, the output end of a semiconductor commutake device formed by three-phase bridged six semiconductor switching element groups 2Q1 to Q6 on both ends of the DC power supply 1 is connected to the input end of the armature winding 4 of the motor body 3.

Using the induced voltage signal induced in the armature winding 4 by the rotation of the magnet rotor 5, the control means 12 converts it into a signal for energizing or cutting off the semi-rod switching element group 2 in the semiconductor commutator device. and rotate the magnet rotor steadily.

As shown in FIG. 6, spike noise occurs in the induced voltage signals 4-U phase, 4-■ phase, and 4-W phase induced in the armature winding 4 as the semiconductor switching element group turns on and off. Therefore, they are removed by the signal converting means 6, and each 9
0° phase delay triangular wave signal 6-U phase, 6-■ phase,
Comparator group 7 (hereinafter the position detection circuit will be referred to as a comparator group (explained as). In this conventional example, as can be seen from the waveform diagram in FIG.
A 7-W phase output signal is created using a 6-U phase signal, and each of these is a solid wave with a phase shift of 1000, and these signals are sent to the switching means 11 as a rotor position detection signal. The semiconductor switching element group 20 is energized and cut off based on the three-phase logic level that is input and output to the control means 12 during steady rotation. With this method, the signals of each phase input to the comparator group 7 follow the load fluctuations accordingly, so stable operation can be maintained. By the way, at the time of startup, the magnet rotor 5 is in a stopped state, so no induced voltage signal is generated in each phase. Therefore, after generating the activation signal of the start command means 14, the output signal of the synchronizing signal generating means 8 is inputted to the rotating magnetic field generating means 9.
Create the 29-ty phase, 9-V phase, and 9-W phase.

These three-phase synchronous signals are input to the switching means 11, and at the time of startup, these signals are output to the control means 12 to generate a rotating magnetic field in the armature winding and forcibly rotate the magnet rotor. When the magnet rotor 5 rotates, an induced voltage is generated in the armature winding 4, so that rotation of the magnet rotor can be detected.

After detection, the output signal from the switching means 11 is changed to the output signal 7-U phase of the comparator group 7 by the signal from the switching command means 10.
The morph 3 switches to the 7-■ phase and the 7-W phase, and rotates steadily. The motor is driven as a synchronous motor until it switches from the 3-phase 1■ signal to the 3-phase induced voltage signal of the comparator group 7 after starting up. Synchronized three-phase rUJ J9 (generally the same wave number of the signal also increases and accelerates the magnet rotor. This is because the magnet rotor 5 has a certain moment of inertia, and the rotation of the armature winding 4 This is to follow the magnetic field and perform stable starting rotation.
According to the example of Publication No. 520, three-phase synchronizing signals 9-U phase, 9
-■ phase, 9-W phase and output signal 7 of comparator group 7 = U phase,
A circuit 13 for detecting the phase difference between the 7-■ phase and the 7-W phase is added, and after detecting that the phase difference between the two has become approximately zero, a switching command signal is output to the switching command means 10. 11 is switched to the output signal of comparator group 7, and these signals are input to control means 12. This is the three-phase synchronous signals 5+9-U phase, 9-■ phase, 9-W phase and the output signal 7-U phase of the comparator group 7 when the motor is rotating as a synchronous motor.

The phase relationships between the 7-V phase and the 7-W phase do not necessarily match, causing a phase shift. Therefore, the timing at which Q1 to Qst of the semiconductor switching element group 2 are turned on and off by the three-phase synchronous signal is different from the timing at which Q1 to Q6 of the semiconductor switching element group 2 are turned on and off by the three-phase output signal of the comparator 7. This results in a failure, resulting in a loss of synchronization and a halt. Furthermore, even if there is no step-out, an excessive current flows through the group of semiconductor switching elements, damaging them. In order to prevent these, if the phase difference between the three-phase synchronization signal and the a-phase output signal of the comparator group 7 is detected, and the switching is performed after detecting that the phase difference between the two has become approximately zero, the above-mentioned semiconductor There is no deviation in the on/off timing of the switching element groups 2a01 to Q6, and switching proceeds smoothly, allowing stable operation of the motor 3.

Problems to be Solved by the Invention The above conventional configuration requires a special circuit and its control to increase the number of equal waves, and also requires a circuit to detect the phase difference between the three-phase synchronization signal and the comparator group. However, there was a problem in that the entire system became complicated.

The present invention solves such conventional problems, and allows stable operation of the motor from startup without using the above-mentioned time-consuming circuit. It is an object of the present invention to provide a brushless motor drive device that also suppresses excessive current to a switching element group.

In order to solve the above-mentioned problem, the brushless motor drive device of the present invention has a method for solving the above-mentioned problem, in which the signal of the rotating magnetic field generating means is generated by the signal of the synchronizing signal generating means of a certain constant @ wave number and the comparator group is connected from the time of startup. The magnet rotor is started to rotate by increasing the power supply voltage within a certain low voltage until switching to the signal, and rotation is detected using the induced voltage signal, and after detection, a switching command signal is generated, and a It is constructed with a position detection circuit that can operate stably even if there is a phase difference between the phase synchronization signal and the comparator group.

Function: The present invention suppresses the power supply voltage within a certain low voltage range until switching due to the above configuration, so that no excessive current flows, and the phase difference between the three-phase synchronizing signal and the three output signals of the comparator group is reduced. Since the deviation is within a certain relationship, the motor can be operated stably without step-out during switching.

EXAMPLE Hereinafter, an example of the present invention will be explained using an example of an A-phase winding with reference to the accompanying drawings.

FIG. 1 is a schematic sequence diagram of an embodiment of the present invention, FIG. 2 is an overall configuration diagram, and FIG. 3 is a semiconductor switching element group 2 using an output signal of a comparator group 7 which is used as an induced voltage signal.
4 shows the phase relationship between the timing diagram of the semiconductor switching element group 2 according to the synchronizing signal during synchronous rotation and the timing diagram of the semiconductor switching element group 2 according to the output signal of the comparator group 7. .

First, explanation will be given using the schematic sequence diagram shown in Figure 1 and the configuration diagram of the second cap body. After the start command means 14 generates a signal, the output signal of the synchronization signal generation means 8 which outputs a certain same wave number is inputted to the rotating magnetic field generation means 9, and three-phase synchronization is performed with eight constant wave numbers each having a phase shift of 120 degrees. Signal 9-υ phase, 9-■ phase, 9
-Create W phase. The switching means 11 (
For example, a multiplexer), these signals are outputted to the control means 12 at startup, and the control means 12 controls energization and cutoff of Q1 to Q6 of the semiconductor switching element group 2 depending on the respective logic levels. Then, the power supply 1 (for example, a switching power supply) that drives the motor 3 is increased within a certain low voltage, and a rotating magnetic field is generated in the armature winding 4 to forcibly rotate the magnet rotor.

In this way, once the magnet rotors are energized, an induced voltage is generated in the armature winding 4, and then the switching command means 10
generates a switching command signal from and controls the signals 7-U phase, 7-■ phase, and 7-W phase signals output from the comparator group 7, which are rotor position detection signals, by switching the switching means 11. The output signal is outputted to the means 12, and after that, based on these logic levels, Q1 to Q6 of the semiconductor switching element group 2 are controlled, and the motor G is rotated steadily.

Next, a method of creating the output signals 7-U phase, 7-■ phase, and 7-W phase of the comparator group 7, which are the rotor position detection signals in one embodiment of the present invention, will be explained with reference to FIG. In Fig. 3, the waveforms of the induced voltage signals at each armature winding terminal are 4-U phase,
4-■ phase and 4-W phase. If we look at the U phase,
The section from Oo to 60'' and the section from 180° to 240° are open and not connected to the power supply.
to 180°, from 240° to 30° on the e side of power supply 1.
0″′ is connected to the Q side of the power supply 1.

In other words, from 60° to 180° and >40°, where the amplitude of the waveform of the induced voltage signal at the armature winding terminal is maximum.
The motor can be efficiently rotated by passing current through the KU phase when the angle is 360 degrees from .

The same applies to the other V-phase and W-phase.

Now, the induced voltage signal of each armature winding terminal 4- U phase, 4
The -■ phase and the 4-W phase generate spike noise as the semiconductor switching element group 2 turns on and off, so they are removed by the signal conversion means 6. What is different from the conventional example is that the circuit of the signal conversion means 6 is It does not require a large time constant, but simply removes spike noise within the morph drive voltage range, and does not shift the phase. Therefore, as shown in Figure 3, from the 4-U phase to the 6 with a slightly smooth waveform.
-U phase (Mit) K, 4-V phase to 6-V phase (solid line)
The 4-W phase is converted into the 62-W phase (solid line). Of these converted signals, for example, the 6-U phase input to the comparator group 7 in FIG. 2, the other a-V phases and the 6-
The waveform of the 7-U phase is the result of a comparison in magnitude with a signal obtained by dividing and combining the W phase using resistors (indicated by the dashed line in the %3 diagram). By comparing the magnitudes of the combined signals of the e'' phase, 6-W phase, and 6-U phase, we can determine the 7-V phase, 6-W phase, and 6-U phase.
A 7-W phase output signal is obtained by comparing the magnitudes of the combined signals of the 6-V phase and the 6-V phase. Therefore, unlike the conventional example, 6-
The U-phase signal creates the output signal of the comparator group 7-U phase, the e-v phase signal creates the 7-V phase, and the 6-W phase signal creates the 7-W phase output signal. These are square waves with a phase shift of 120 degrees, and are input to the switching means 11 as rotor position detection signals, and output to the control means 12 during steady rotation, and are output to the control means 12 at the logic level (6 bits) of these 1 synchronous three-phase signals. mode), the semiconductor switching element group 2 is energized and cut off to maintain rotation of the magnet rotor by five rotations. In addition, as a signal input to the comparator group 7, the one shown by the two-dot chain line in FIG. A similar output signal of the comparator group 7 can be obtained by comparing the magnitude with this signal. Among the output signals of these comparator group 7, for example, the 7-U phase signal is created based on the information of the induced voltage signals of the ■ phase and W phase. Even if the phase relationship between the phases of
The waveform to be compared also follows the change accordingly, resulting in a stable position detection signal. The same applies to other phases. In addition, since the time constant of the signal converting means 6 is small and the transient characteristics are good, as can be seen from Fig. 3, the signal converting means 6 is connected to the armature winding of each phase at the point where the amplitude of the waveform of the induced voltage of each phase is maximum. Since the semiconductor switching element group 2 is energized, it can rotate stably with a high drive rate. Note that in order to increase the rotation speed of the magnet rotor during steady rotation, the voltage at Ichihara 1 may be increased.

Next, from the rotation by the synchronization signal to the switching fingering means 10
However, in one embodiment of the present invention, the output signal (square wave) of the comparator group 7 based on the induced voltage signal is used as the rotation detection signal. These signals (black 7 lines) are counted, and when an appropriate number of ticks are counted, a switching command signal is generated. Therefore, the switch should be made after determining whether it is rotating reliably.

Next, at the stage of switching the signal output to the control means 12,
The reason for stable switching without step-out will be explained with reference to FIG. In Fig. 4, the three-phase synchronous signals (indicated by diagonal lines in the figure) during synchronous rotation before switching: 9-U phase, 9-■ phase, 9-
The semiconductor switching element group 2 is energized in the W phase (
The control of shutoff (indicated by diagonal lines in the figure) is shown from phase 9-Q1 to phase 9-06. The output signals 7-U phase, 7-■ phase, and 7-W phase of the comparator group 7, which are position detection signals during the synchronous rotation, are the three-phase synchronous signals 9-U phase, 9-■ phase, 9-W phase. It is normal for the phase to be in a state that is ahead of the phase.

The output signal of the comparator group 7 is used to control the energization (indicated by thick lines in the figure) of the semiconductor switching element group 2 from phase 7-Q1 to phase 7-06.

For example, as shown in Fig. 4, when the output signal of comparator group 7 has a phase lead of up to 60 degrees from the three-phase synchronous signal (this is caused by the relative position between the magnetization of the magnet and the armature winding), this −
No matter what time a cut command is issued during synchronization, only one of the semiconductor switching element groups changes. In other words, a change occurs from Q3 to Ql during 00 to 60 degrees, but if the control is based on a synchronization signal, the 9-Q1 phase is off and the <7-01 phase is off based on the output signal of comparator group 7. On, 9-Q3 phase is on and 7-〇〇 phase is off. The control of the synchronization signal from 60° to 12σ is the same. That is, the direction in which the magnet rotor 5 is to be rotated is the same, and the instant this state is switched without changing, the magnet rotor 5 is shifted by 60 degrees in the rotation direction and rotated. In other words, it is impossible for the motor to step out and stop. The output signals from the comparator group 7 are signals with a phase shift of 12σ, and these are signals that follow load fluctuations, so they continue to rotate stably both at the moment of switching and after switching. It is possible.

Effects of the Invention As described above, the brushless motor drive device of the present invention provides the following effects.

(1) During synchronous rotation at startup, the voltage is kept within a certain low voltage range, so no overcurrent flows through the semiconductor switching element group, etc., which is effective in preventing damage and deterioration of the elements.

(2) There is no need for a circuit to detect the phase difference between the synchronization signal and the rotor position detection signal when switching from startup to steady rotation, and the circuit configuration is extremely simple and allows smooth transition from startup to steady rotation at low cost. It can be configured as follows.

(3) In the conventional configuration in which the rotor is accelerated while increasing the synchronization signal, the control to change the period is complicated, but according to the present invention, the frequency of the synchronization signal can be kept constant, so it is very simple. Therefore, the configuration is also simple.

[Brief explanation of drawings]

Fig. 1 is a general sequence diagram of the wood generator 111'I-embodiment, Fig. 2 is its overall configuration diagram, Fig. 3 is a waveform diagram of each 115 for the induced voltage signal, Fig. 4 5 is a timing chart of a semiconductor switching element based on the three-phase +91 signal during synchronous rotation and the output signal of a position detection circuit, FIG. 5 is an overall configuration diagram of a conventional example, and FIG. This is a waveform diagram of each part. 1-...Power supply, 2...Semiconductor switch element group, 3
・Motor, 4... Armature winding, 5... - Magnet rotor, 6... Signal exchange means, 7... Position detection circuit (
comparator group), b--synchronous signal generating means, 9--rotating magnetic field generating means, 10...1. IJ li! ! 8
Command means, 11--Switching means, 12- Control means,
14-Start command means. Agent's name: Attorney's name: Masao Nakao (1 person)
Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure =449-

Claims (2)

[Claims] (1) Connect multiple phases to an ungrounded neutral point, and connect n pieces (
An armature winding divided into 2 m poles (m is 1 or more), a group of semiconductor switching elements that conduct or cut off current to the armature winding, and a magnet rotor divided into 2m poles (m is 1 or more). a motor having a motor, a power source for driving the motor, a start command means, a synchronous decoding generating means for outputting a certain frequency, and a rotating magnetic field applied to the armature winding using the signal output from the signal generating means. a position detection circuit that detects the relative position of the armature winding and the magnet rotor based on a voltage signal induced in the armature winding; and an output of the rotating magnetic field generation means. a switching means for selecting, switching and outputting a signal and an output signal of the position detection circuit; a switching command means for giving a switching command to the switching means; and controlling the switching element group using the output signal of the switching means. The switching command means fixes the voltage of the power supply to a certain low voltage during synchronous rotation after generation of the signal from the start command means, starts the rotation of the magnet rotor, and controls the induced voltage. A brushless motor drive device configured to detect a signal, and after detecting the induced voltage signal, switch to an output signal of the position detection circuit according to a signal from the switching command means to steadily rotate the magnet rotor. (2) The position detection circuit includes a signal conversion means for appropriately converting the signals induced in the armature windings of the plurality of phases into appropriate signals, and a virtual circuit that combines the output signals of all the plurality of phases after the signal conversion means. A comparator that compares the magnitude of the neutral point signal and arbitrary output signals of the plurality of phases, or compares the magnitude of a signal obtained by combining the output signal of a certain arbitrary phase and the output signal of other phases. Claim 1 consisting of a group
The brushless motor drive device described in Section 1.