JPS61135379A - Brushless motor drive device - Google Patents

Abstract

PURPOSE:To stably operate a motor even at phase difference displacing time by securing to a low voltage until switched to a signal from rotating magnetic field generating means and a signal of comparator group from starting time. 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 14, a period signal of the prescribed frequency is input from generating means 8 to rotating magnetic field generating means 9 to form 3-phase synchronizing signals 9-U-W phases displaced at 120 deg., 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 secured to low voltage to forcibly rotate a magnet rotor 5. Thus, after the prescribed time is elapsed, 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] Industrial application field Tree @EfJ relates to brushless morphs, and in particular detects the relative position of the magnet rotor and armature winding by the induced voltage induced in the armature winding. FiJIJ with simple configuration
This relates to a brushless morph for stable rotation.

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

For the sake of convenience, we will explain this using an example of phase A. In other words, the output end of a semiconductor commu- taker device formed by 3-phase bridging of six semiconductor switching element groups 2Q+ to Q6 on both ends of a DC power source is referred to as a morph. Armature winding 4 of main body 3
Connect to the 0 input terminal. Using the induced voltage signal induced in the N 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 semiconductor switching element group 2 in the semiconductor commutator device. Rotate steadily. As shown in FIG. 6, spike noise occurs in the induced voltage signals 4-U phase, 4-V phase, and 4-W phase induced in the armature winding 4 as the semiconductor switching element group 2 turns on and off. Therefore, it is removed by the signal conversion means 6, and converted into triangular wave-like signals 6-U phase, 6-V phase, and 6-W phase, each with a phase delay of 9-0 degrees, and a hypothetical example in which each of the three phases is synthesized with a resistor. The magnitude of the neutral point signal and each phase is compared by a comparator group 7 which is a position detection circuit (hereinafter, the position detection circuit will be explained as a comparator group). In this conventional example, as can be seen from the waveform diagram in FIG. 6, the output signal of the comparator group 7-U phase is
7-V phase with a-W phase signal, 7-W with 6-U phase signal
I am creating phase output signals and they are each 120
These signals are input to the switching means 11 as rotor position detection signals, and are output to the control means 12 during steady rotation to control the semiconductor switching element group based on the logic levels of the three phases. Controlling energization and interruption - With this method, the signals of each phase input to the comparator group 7 follow the load fluctuations accordingly, so stable operation is maintained. By the way, at the time of startup, the magnet rotor 6 is in a stopped state, so no induced voltage signal is generated in each phase. Therefore, after generating the signal from 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, and three-phase synchronizing signals 9-U phase, 9-V phase, 9-W phase with a phase shift of 1200 are generated. The three-phase synchronizing signals to be created 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 the output signal from the switching means II 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 is switched to the 7-V phase and the 7-W phase, and the morph 3 is driven as a synchronous morph until the 3-phase synchronous signal after startup is switched to the 3-phase induced voltage signal of the comparator group 7.
The frequency of the output signal of the Domei signal generating means 8.

Generally, the frequency increases with time, and the frequency of the three-phase synchronization signal synchronized therewith also increases to accelerate the magnet rotor. This is because the magnet rotor 5 has a certain moment of inertia and follows the rotating magnetic field of the armature winding 40 to perform stable starting rotation.

Furthermore, according to the example of Japanese Patent Publication No. 59-36520, the three-phase synchronizing signals 9-U phase, 9-V phase, 9-W phase and the output signal 7-U-17-V phase of the comparator group 7 , 7-A circuit 13 for detecting the phase difference between the W phases is added, and after detecting that the phase difference between the two has become approximately zero, a switching command signal of the switching command means 10 is outputted, and an output signal of the switching means 11 is output. is switched to the output signal of the comparator group 7, and these signals are input to the control means 12.

When rotating as a synchronous motor, the three-phase synchronous signals 9-U phase, 9-V phase, 9-W phase and the output signals 7-U phase, 7-V phase, 7-W phase of the comparator group 7 are generated. The phase relationship between the W-phases does not necessarily match, causing a phase shift. Therefore, Q1 of semiconductor switching element group 2 is
Since the timing to turn on and off Q6 is different from the timing to turn on and off Q1 to Q6 of the semiconductor switching element group 2 based on the three-phase output signal of the comparator 7, the switching fails and the step out stops. Furthermore, even if no synchronization occurs, an excessive current flows through the semiconductor switching elements, damaging them. In order to prevent these, if the phase difference between the three-phase identical signal and the three-phase output signal of the comparator group 7 is detected, and the phase difference between the two becomes approximately zero, the switching can be performed. There is no deviation in the on/off timing of switching elements 01 to Q6 of the switching element group 2, and the switching proceeds smoothly, allowing stable operation of the motor 3. Problems to be Solved by the Invention In the above conventional configuration This method requires a special circuit and its control to increase the frequency, and also requires a circuit to detect the phase difference between the three-phase synchronization signal and the comparator group, which has the problem of complicating the entire system. was.

The present invention solves these conventional problems, and allows stable operation of the motor from startup without using the special circuit as described above, and prevents step-out even when switching, using a semiconductor switching element. It is an object of the present invention to provide a brushless motor drive device that also suppresses excessive current to the motor group.

Means for Solving the Problems In order to solve the above-mentioned problems, the brushless motor drive device of the present invention provides a signal from the rotating magnetic field generating means based on a signal from the synchronizing signal generating means having a certain frequency and a comparator group from the time of startup. This is a position detection circuit that fixes the voltage at a certain low voltage until it switches to the signal of It is composed of

Function The present invention fixes the power supply voltage to a certain low voltage until switching due to the above configuration, so that no excessive current flows, and 3.
The phase difference between the phase synchronization signal and the three output signals of the comparator group is within a certain relationship, and the motor can be operated stably without step-out during switching.

Embodiment Hereinafter, one embodiment of the present invention will be explained using an example of a three-phase winding with reference to the accompanying drawings.

FIG. 1 is a schematic sequence diagram of an embodiment of the present invention, and FIG. 2 is an overall configuration diagram. Fig. fJ3 is a timing diagram of semiconductor switching element group 2 according to the output signal of comparator group 7 based on one induced voltage signal, and Fig. 4 is a timing diagram of semiconductor switching element group 2 according to a synchronous signal during synchronous rotation. This shows the phase relationship of the timing diagram of the semiconductor switching element group according to the output signal of the comparator group 7 and the output signal of the comparator group 7.

First, explanation will be given with reference to the schematic sequence diagram in FIG. 1 and the system configuration diagram in FIG. Three-phase synchronous signals 9-U phase, 9-V phase, 9-U phase, 9-V phase, 9-
Create W phase.

These three-phase synchronizing signals are input to the switching means 11 (for example, a multi-branch), and at startup, these signals are output to the control means 12, and when the respective logic levels are adjusted, the control means 12 controls the semiconductor switching element group 2 from 01 to 01. Controls energization and cutoff of Q6. Then, motor 3 is FFAifJ
) A power supply 1 (for example, a switching voltage) is fixed at a certain low voltage, and a rotating magnetic field is generated in the armature winding 4 to forcibly rotate the magnet rotor.

Once the magnet rotor rotates in this way, an induced voltage is generated in the armature winding 4. Therefore, after a certain period of time has elapsed, a switching command signal is generated from the switching command means 10, and the switching means 11 is switched. , the signals 7-U phase, 7-V phase, and 7-W phase signals output from the comparator group 7, which are rotor position detection signals, are outputted to the control means 12 and thereafter set to these logic levels. Q1 to Q6 of the semiconductor switching element group 2 are controlled to rotate the motor 3 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 rotor position detection signals in one embodiment of the present invention, will be described with reference to FIG. In Fig. 3, the waveforms of the induced voltage signals at each armature winding terminal are 4-U phase,
4-V phase and 4-W phase. If we look at the U phase,
The section from 0° to 60° and the section from 180° to 2400° are open and not connected to the power source. Also, 60°
to 1800, from 240° to 30° on the e side of power supply 1.
00 is connected to the e side of the power supply 1. That is,
In this way, the amplitude of the waveform of the induced voltage signal at the armature winding terminal is maximum from 60° to 180° and from 240° to 360°.
The motor can be rotated efficiently by passing current through the U phase when the angle is .degree. The same applies to the other V-phase and W-phase.

At Hanawa, the induced voltage signal of each armature winding terminal 4-U phase, 4-
The V phase and 4-W phase generate spike noise when the semiconductor switching element group 2 turns on and off, so they are removed by the signal conversion means 6. What differs from the conventional example is the time constant of the circuit of the signal conversion means 6. It does not take a large value, but simply removes spike noise within the morph drive voltage range, and does not shift the phase. Therefore, the third
As shown in the figure, from 4-U phase to 6 to 6 with a smooth waveform.
U phase (shown as a solid line) K, 0 converted from 4-V phase to 6-V phase (shown as a solid line) K, 0 converted from 4-W phase to 6-W phase (shown as a solid line) Among them, for example, the 6-U phase input to the comparator group 7 in FIG.
This is the waveform of the 7-U phase, which is the result of comparing the magnitudes of the signals obtained by dividing and combining the -V phase and the 6-W phase using resistors (indicated by the dashed line in Figure 3). In addition, 6-V phase, 6-W phase and 6-U
A 7-V phase output signal is obtained by comparing the magnitudes of the combined signals of the phases, and a 7-W phase output signal is obtained by comparing the magnitudes of the combined signals of the a-W phase, the 6-U phase, and the 6-V phase. Therefore, the difference from the conventional example is that the output signal of the comparator group 7-U phase is determined by the 6-U phase signal, the 7-V phase is determined by the 6-V phase signal, and the 7-V phase is determined by the 6-W phase signal.
This is to create a W-phase output signal, each of which is a square wave with a phase shift of 120°, and is input to the switching means +1 as a rotor position detection signal, and during steady rotation, is output to the control means 12. The magnet rotor 5 continues to rotate by controlling the energization and cutoff of the semiconductor switching element group 2 based on the three-phase logic levels (six modes) of the cycle. In addition, as a signal input to the comparator group 7, the one shown by the two-dot chain line in Fig. 3 is a pseudo neutral point where all the signals of the 6-U phase, 6-V phase, and 6-W phase are combined with a resistor. A similar output signal from the comparator group 7 can be obtained by comparing the magnitude with this signal. Among the output signals of comparison 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, and by this, the phase of the U phase and the Even if a load fluctuation occurs and the waveform of each phase changes accordingly, the waveform to be compared will follow the change accordingly, resulting in a stable position detection signal. The same goes for the phase of the pond. In addition, since the signal conversion means 60 has a small time constant and good transient characteristics, as can be seen from Figure 3, the semiconductor connected to the armature winding of each phase is used at the point where the amplitude of the waveform of the induced voltage signal of each phase is maximum. Switching element group 2 is energized, and stable rotation can be achieved with high efficiency.To increase the rotation speed of the magnet rotor during steady rotation, simply increase the voltage of the power supply. .

Next, after a certain period of time has elapsed from the rotation caused by the synchronization signal, a signal from the switching command means 10 is generated, and the signal is switched to the output signal from the comparator group 7. In one embodiment of the present invention, the synchronization signal generation It is configured to count the signals (tallock) of the means and generate a switching command signal when an appropriate count is reached. Note that the structure of this switching command is not limited to the one embodiment of the present invention, and may be a command from a timer or a changeover switch from a separate control means.

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, three-phase synchronous signals (indicated by diagonal lines in the figure) during synchronous rotation of the song to be switched: 9-U phase, 9-V phase, 9-
The semiconductor switching element group 2 is energized in the W phase (
The shutoff control (indicated by the needle ° line in the figure) is changed from phase 9-01 to phase 9-
It is shown in Q6 phase.

Comparator group 7 which is a position detection signal during the synchronous rotation
output signal? The -U phase, 7-V phase, and 7-W phase are usually in a phase-advanced state than the three-phase synchronous signals 9-U phase, 9-V phase, and 9-W phase. The output signal of the comparator group 7 is used to control the energization (indicated by a bold line in the figure) and cutoff of the semiconductor switching element group 2 from phase 7-01 to phase 7-0. For example, as shown in Fig. 4, when the output of the comparator group 7 (signal has a maximum phase lead of 60 degrees (this is caused by the relative position between the magnetization of the magnet and the armature winding) than the three-phase synchronous signal, No matter what switching command is issued during this period, only one semiconductor switching element group 2 changes.In other words, from 0° to 60°, from Q3 to 01
However, if the control comes from the synchronization signal, it will change to 9-
Based on the output signal of comparator group 7 when Q1 phase is off, <7-0
Phase 1 is on, phase 9-Q3 is on, and phase 7-Q is off. And from 60° to 120° of the synchronization signal, it is the same for 9-01. In other words, the direction in which the magnet rotor is to be rotated is the same, and the instant the switch is made without changing this state, the magnet rotor 5 is rotated 60 degrees in the rotation direction.
There is no need to shift it to 0 and rotate it. In other words, it is impossible for the motor to step out and stop. In addition, the output signals from the comparator group 7 are signals with a phase shift of 120 degrees, and since these are signals that can follow load fluctuations, 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 morph drive device of the present invention provides the following effects.

(1) During synchronous rotation at startup, the voltage is fixed at a certain low voltage, so no overcurrent flows to the semiconductor switching elements, etc., which has the effect of preventing element deterioration. (2) Steady rotation from startup UJ There is no need for a circuit to detect the phase difference between the synchronization signal and the rotor position detection signal when switching to the rotor, and the phase difference is always kept below a certain relationship, so the circuit configuration is extremely simple and smooth from startup to steady rotation. It can be implemented at low cost.

(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, and the voltage at startup is Since the voltage may be kept constant, the voltage control of the power supply is also non-a
Ic fm becomes simple, and the overall configuration and sequence are also simplified.

[Brief explanation of drawings]

Fig. 1 is a schematic sequence diagram of an embodiment of the present invention, Fig. 2 is an overall configuration diagram of the same, Fig. 3 is a waveform diagram of each part of the same induced voltage signal, and Fig. 4 is a three-dimensional diagram during synchronous rotation. A timing chart of the semiconductor switching element for the phase synchronization signal and the output signal of the position detection circuit, FIG. 5 is an overall configuration diagram of the conventional example,
FIG. 6 is a waveform diagram of each part of the induced voltage signal. 1... Power supply, 2... Semiconductor switching element group, 3... Morph, 4... Armature winding, 5... Magnet Rotor, 6... Signal conversion means, 7... Position detection circuit (comparator group)
, 8... Synchronous signal generating means, 9... Rotating magnetic field generating means, 10... Switching command means, +1
......Switching means, 12...Control means, 1
4...Start command means. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3 Figure 4 Figure 5

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 supply for driving the motor, a start command means, a synchronization signal generation means for outputting a certain frequency, and a rotating magnetic field applied to the armature winding using the signal output from the signal generation 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. During the synchronous rotation after the signal from the start command means is generated, the voltage of the power source is fixed at a certain low voltage, and the magnet rotor is started. A brushless motor drive device comprising a separate changeover switch, and after a certain period of time has elapsed, a signal from the changeover command means is used to switch to an output signal from the position detection circuit 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.