JPS61135383A - Brushless motor drive device - Google Patents

Abstract

PURPOSE:To stably operate a motor at switching time by increasing within a low voltage until switched to a signal from rotating magnetic field generating means and a signal of comparator group from starting time, detecting the rotation and generating a switching command signal. 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 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 rotor 5. Thus, after the induced voltage is generated in an armature winding 4, 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 of a magnet rotor and an armature winding by an induced voltage induced in a Ti coil. 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 commutator 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. Then, 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 semiconductor switching element group 2 in the semiconductor commutator device. Rotate steadily. In addition,
As shown in FIG. 6, spike noise is generated 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 2 turns on and off. Triangular wave signals 6-U phase and 6-V phase are removed by the signal converting means 6 and are delayed by 90 degrees in phase.

Comparator group 7, which is a position detection circuit, detects the magnitude of each phase and the virtual neutral point signal which is converted into 6-W phase and synthesized three phases using resistors. ) to compare. In this conventional example, as can be seen from the waveform diagram in FIG. A 7-W phase output signal is created using an 8-U phase signal, and each of them is a square wave with a phase shift of 1200, and these signals are used as a rotor position detection signal to be used by the switching means 1.
1 and output to the control means 12 during steady rotation to control energization and cut-off of the semiconductor switching element group 2 based on the three-phase logic levels. 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 signal from the start command means 14, the output signal from the synchronizing signal generating means 8 is transferred to the rotating magnetic field generating means 9.
A three-phase synchronous signal 9-U phase with a 120° phase shift input to the
Create 9-■ 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 5 can be detected. Then, the output signal from the switching means 11 is changed to the output signal 7-U of the comparator group 7 by the signal from the switching command means 10 after detection.
phase.

The motor 3 is switched to the 7-V phase and the 7-W phase, and the motor 3 rotates steadily. In addition, until the 3-phase synchronous signal after startup is switched to the 3-phase induced voltage signal of the comparator group 7, it is driven as a synchronous motor.
Generally, the frequency of the output signal of the synchronization signal generating means 8 is increased over time, and the frequency of the three-phase synchronization signal synchronized therewith is also increased 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 4 to perform stable starting rotation. And furthermore, special public service No. 59-365205
゜Report, )゜ゎゎ, 3-phase synchronous signal 4゛2. phase, 9
-■ phase, 9-W phase and output signal of comparator group 7 7-U phase, 7
A circuit 1a for detecting the phase difference between the -■ 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, and the switching means 11 The output signal of the comparator group 7 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-■ phase, 9
-W phase and output signals of comparator group 7 7-U phase, 7-■ phase.

The phase relationship between the 7-W phases does not necessarily match, causing a phase shift. Therefore, the timing at which Q, ~Q6 of semiconductor switching element group 2 are turned on and off by the 3-phase synchronous signal and the timing at which Q1 ~ Q6 of semiconductor switching element group 2 are turned on and off by the 3-phase output signal of comparator 7 are different. This causes a failure in switching, resulting in a loss of synchronization and a stop.

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 synchronizing signal and the G-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 Q, ~Q6 of switching element group 2,
This allows smooth switching and 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 frequency, and also requires a circuit to detect the phase difference between the three-phase synchronization signal and the comparator group. This has the problem of complicating the entire system.

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 at a certain constant frequency, and a comparator group from the time of startup. The magnetic rotor is started to rotate by increasing the voltage within a certain low voltage until it switches to the signal of 3-phase synchronous signal. It is constructed with a position detection circuit that can operate stably even if there is a phase difference between the comparator group 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 also switches to steady rotation after detecting that it is rotating.
In addition, the phase difference between the three-phase synchronizing 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, an embodiment of the present invention will be described 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, FIG. 2 is an overall configuration diagram, and FIG. 3 is a semiconductor switching element group 2 based on an output signal of a comparator group 7 based on 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 with reference to a schematic sequence diagram in FIG. 1 and a second cap body configuration diagram. After the activation command means 14 generates a signal, the output signal of the synchronization signal generation means 8 which outputs a certain constant frequency is inputted to the rotating magnetic field generation means 9, and three-phase synchronization signals 9- of constant frequency with a phase shift of 120 degrees are inputted to the rotating magnetic field generation means 9. U phase, 9-■ phase, 9-
Create W phase.

These three-phase synchronization signals are input to the switching means 11 (for example, a multiplexer), and at startup, these signals are output to the control means 12, and when the respective logic levels are adjusted, the control means 12 switches the semiconductor switching element group 2 from Q1 to Controls energization and disconnection of Q6.

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.

Once the magnet rotor 5 rotates in this manner, an induced voltage is generated in the armature winding 4, so that the switching command means 10 generates a switching command signal, and the switching means 11 is switched. The signals 7-U phase, 7-■ phase, and 7-W phase signals outputted from the comparator group 7, which are position detection signals, are outputted to the control means 12, and after that, they are set to these logic levels and the semiconductor switching elements are outputted. The motor 3 is rotated steadily by controlling Q, to Q6 of group 2.

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-■ phase and 4-W phase. If we look at the U phase,
The section from 0° to 60° and the section from 180° to 240° are open and not connected to the power supply. Also, 60°
to 1800, from 240° to 30° to the ■ side of power supply 1.
Until 0°, it is connected to the O side of the power source 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.

Now, the induced voltage signals of each armature winding terminal 4-U phase, 4-
Phase (3) and 4-W phase generate spike noise as the semiconductor switching element group 2 turns on and off, so it is removed by the signal conversion means 6. What is different 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 motor drive voltage range, and does not shift the phase. Therefore, the third
As shown in the figure, the waveform is slightly smooth from the 4-U phase to the 6-
From the 4-V phase to the 6-V phase (solid line), the 4-
The W phase is converted to the 6-W phase (solid line). Among these converted signals, for example, a signal (the 6-U phase, which is input to the comparator group 7 in FIG. (Indicated by the dashed-dotted line in Figure 3)
The result of comparing the magnitude with that is the waveform of the 7-U phase. In addition, by comparing the magnitudes of the combined signals of the 6-V phase, 6-W phase, and 6-U phase, the 7-V phase, a-W phase, 6-U phase, and 6-U phase are compared.
By comparing the magnitude of the combined V-phase signal, a 7-.W-phase output signal is obtained. 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-W phase is determined by the 6-W phase signal. The point is to create phase output signals, each of which is a square wave with a phase shift of 1200 degrees, and is used as a rotor position detection signal by the switching means 1.
1, and during steady rotation, it is output to the control means 12, which controls the energization and interruption of the semiconductor switching element group 2 based on the three-phase logic levels (6 modes) of one cycle, and controls the magnet rotor 5. continues to rotate. In addition, the signals input to the comparator group 7 shown by the two-dot chain line in FIG.
This is a pseudo-neutral point signal in which all the signals of the 8-U phase, 6-V phase, and 6-W phase are combined with a resistor, and the output signal of the comparator group 7 is the same even when compared in magnitude with this signal. is obtained. 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.
The phase relationship between the phase of a phase and other phases is accurate, and 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. That's why it happens. The same applies to other phases.

In addition, since the time constant of the signal conversion means is small and the transient characteristics are good, as shown in Figure 3, each phase is connected to the armature winding at the point where the waveform amplitude of the induced voltage signal 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, it is sufficient to increase the voltage of voltage #1.

Next, from the rotation by the synchronization signal, the switching command means 10
The signal is generated and switched to the output signal of the comparator group 7. 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 (flocks) are counted, and when an appropriate count is reached, 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,
Reason 9 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 before switching: 9-U phase, 9-■ phase, 9
- energization of the semiconductor switching element group 2 in the W phase;
The shutoff control (indicated by diagonal lines in the diagram) is controlled from the 9-Q1 phase to the 9-Q1 phase.
Shown in phase 〇〇. Output signals of the comparator group 7 which are position detection signals during the synchronous rotation 7-U phase, 7-■ phase, 7-
'W phase is a three-phase synchronizing signal 9-U phase, 9-■ phase, 9-
It is normal for the phase to be in a phase-advanced state compared to the W 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 the 7-01 phase to the 7-Q6 phase.

For example, as shown in Fig. 4, when the output signal of the comparator group 7 has a maximum phase lead of 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), There is only one semiconductor switching element group 2 that changes no matter when a switching command is issued during this cycle.

In other words, during 0° to 60°, a change occurs from Q3 to Ql, but if the control is based on a synchronization signal, the 9-Q1 phase is off, and based on the output signal of the comparator group 7, the 7-01 phase changes. is on, the 9-Q phase is on, and the 7-Q3 phase is off. The control of the synchronous signal from 60° to 120° is the same. That is, the magnet rotor 5
The direction in which the magnet rotor 5 is to be rotated is the same, and the moment the switch is made without changing this state, the magnet rotor 5 is rotated by 60° in the rotation direction.
It's nothing more than one rotation of the shift. In other words, it is impossible for the motor to step out and stop.

Moreover, the output signals from the comparator group 7 are each 120°
The signals are out of phase and can follow load fluctuations, so they can continue to rotate stably both at the moment of switching and after switching.

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, rotation is detected using an induced voltage signal and the voltage is kept within a certain low voltage, so overcurrent to semiconductor switching elements etc. due to motor lock and damage or deterioration of the elements may occur. It has the effect of preventing

(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 phase difference is kept below a certain relationship, and during synchronous rotation, which is prone to step-out. Since the rotation is detected, the reliability of the control of the entire system is improved, and the extremely simple circuit configuration allows smooth operation from startup to steady rotation, and can be configured 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, so it is very easy to control. It is simple and the configuration is also simple.

[Brief explanation of drawings]

Fig. 1 is a schematic sequence diagram of the present invention-embodiment, Fig. 2 is an overall configuration diagram of the same, Fig. 3 is a waveform diagram of each part based on the same induced voltage signal, and Fig. 4 is a three-phase analog during synchronous rotation. FIG. 5 is a timing chart of the semiconductor switching element for the period signal and the output signal of the position detection circuit, FIG. 5 is an overall configuration diagram of a conventional example, and FIG. 6 is a waveform diagram of each part of the induced voltage signal. 1... Power supply, 2... Semiconductor switching element group, 3... Motor, 4... Armature winding, 5...
... Magnet rotor, 6... Signal conversion means, 7...
・Position detection circuit (comparator group), 8... Synchronization signal generation means, 9... Rotating magnetic field generation means, 1o...
...Switching command means, 11...Switching means, 12...
- Control means, 14...Start command means. Name of agent: Patent attorney Toshio Nakao and one other person Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

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 supply is increased over time within a certain low voltage to start the rotation of the magnet rotor, and the switching command means: A brushless motor drive device configured to detect the induced voltage signal, and after detecting the induced voltage signal, switch to the 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 plurality of signal conversion means for converting the voltage signals induced in the armature windings of the plurality of phases into appropriate signals as appropriate, and a plurality of signal conversion means for converting the output signals of all the plurality of phases after the signal conversion means. Compare the magnitudes of the synthesized pseudo-neutral point signal and arbitrary output signals of the plurality of phases, or compare the magnitudes of the output signal of a certain arbitrary phase and the signal obtained by synthesizing the output signals of other phases. A brushless motor drive device according to claim 1, comprising a group of comparators.