JPH01160389A - Driving device of brushless motor - Google Patents

Abstract

PURPOSE:To make a position detector of a rotor and an intermediate memory unnecessary by controlling the timing and period of current flowing to each coil on the basis of a synchronizing clock signal, and at the same time, by making a step operation. CONSTITUTION:Based on a synchronizing clock signal from a synchronizing clock signal generation circuit 1, the timing and the period when a transistor of a current driving circuit 6 is turned ON by a timing controlling circuit 4 are decided. Beside, a clock counter 2 counts the synchronizing clock signal. When a prescribed number, to which the number of counts of the clock counter 2 are attained, is detected by a detection circuit 3, a hold signal is outputted to the timing controlling circuit 4 from a hold reset circuit 5. According to the constitution, stop movement can be made by a fine angle.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF THE INVENTION The present invention relates to a brushless motor drive device capable of step motion at fine angles.

BACKGROUND OF THE INVENTION Conventional brushless motor drive devices detect the position of a rotor using a position detection element, typically a Hall element.
It controls the current flowing through the coil.

This allows the motor to rotate smoothly. Further, by controlling the current flowing through the coil of the motor, it is also possible to control the torque of the motor.

By the way, stepping motors can perform step operations in synchronization with external step pulses, but
Shortening the period of the knob pulses has the disadvantage that the torque becomes extremely small.

Therefore, for example, in a compact cassette player or a soto-table recorder device, a motor is sometimes used to move the head to press the lid against the tape for recording, playback, and erasing. In this case, it is necessary to have a high torque that can stop the rotation of the motor at a specified angle, move the head at high speed, and withstand the load torque associated with the head movement.

Therefore, there have been conventional motors using a brushless DC motor as disclosed in Japanese Patent Application Laid-Open No. 54-57111.

A conventional brushless DC motor will be explained below.

FIG. 6 shows a conventional brushless DC motor. In Fig. 6, w+ l W2, ``5 and W4 are four partial windings, the ends of which are bundled into a star-shaped connection point, which is led to the positive pole of the power supply, and the free connection of each partial winding is The end is led to the negative pole of the power supply via switches 81 to S4.

R is a rotor. The direction of its magnetic pole N-8 is indicated by arrow 61, and Hj*H2 indicates two rotor position detectors. Commutation is performed such that the rotor R rotates in the opposite direction to clockwise rotation, and the commutation angles are 45°, 136°, and 225°.
, 316°.

When the winding W3 is energized, the rotor R rotates the winding w4. When power is applied to w, , and w2 in turn, the rotor R changes angles from 135° to 226° and from 225° to 3
16°, moved in the range of 316° to 45°.

When the winding W2 is energized, the rotor R rotates at an angle of 315° to 45°.
Moved to a range of °. If this instantaneous state of the commutation signal is maintained, the rotor R will be kept pointing towards the energized winding W2. However, at this point a new signal train has already arrived, which attempts to close winding W3. To avoid this, an intermediate storage device 62 is provided, which stores the commutation signal to winding W3 until the next step pulse releases the already existing commutation signal.

This circuit is shown in FIG. 6(b). 63 is a rotor position detector consisting of two Hall elements H1 and H2, 64 is an amplifier that amplifies the output of the Hall element, 65 is a selection circuit that controls the rotor position of the switches S1 to S4 from the output of the amplifier 64, and 66 is a rotor position detector consisting of two Hall elements H1 and H2; Rotor.

67 is a commutation circuit, 68 is an OR circuit, 69 is a preset counter, 610 is an AND circuit, and 611 is an OR circuit.

The output terminal of the selection circuit 66 is connected to the input terminal of the intermediate storage device 62, and the input signal of the intermediate storage device 62 is sent to the commutation circuit 67 connected to the output terminal based on the control signal.

This state is maintained until the next control signal arrives at the input terminal of the intermediate storage device 62. Winding W2 is thus energized by selection circuit 65, so that rotor 66 is held in the direction of this winding, and this state is maintained until intermediate storage 62 receives a new control signal. At this time, selection circuit 6
5 has already selected energization of the winding W2 in accordance with the rotor position. This commutation signal is connected as soon as the intermediate storage device 62 receives the control signal. By repeatedly controlling the intermediate storage device 62, continuous rotor motion is obtained. Furthermore, each time the commutation signals 81 to S4 change, the step function is selected.

It is guided to the selection circuit 5 and then to the external preset counter 69 via the OR circuit. On the one hand, the stepping pulses are led directly to the input terminal of the intermediate storage device, which causes a stepping movement of the rotor. To use such a motor for position setting, an external preset counter 69 is provided, which determines the number of angular steps to be performed. Thereby, the step pulse is supplied to the control input terminal of the intermediate storage device 62 through the AND circuit 610 and the OR circuit 611. Preset counter 6 until the planned position is obtained.
One signal from 9 is sent to AND circuit 610. In this way, each step pulse is briefly introduced into the intermediate storage device 62 until the predetermined number of steps is obtained. New commutation sequences therefore occur continuously at the output of intermediate storage 62 and thus at commutation circuit 67. The motor rotates one angle step in accordance with each step pulse.

Problems to be Solved by the Invention However, in the conventional configuration, a rotor position detector and an intermediate storage device for storing the next step pulse are required, and the number of step angles of the motor is determined by the number of rotor detectors and the motor. Since it depends on the number of poles, it increases the cost of manufacturing the motor and makes it impossible to perform step motion at small angles. Another drawback is that it cannot be stopped reliably at a specified angle.

The present invention solves the above-mentioned conventional problems, and eliminates the need for a rotor position detector and an intermediate storage device for storing the next step pulse, thereby reducing manufacturing costs and allowing step movement at small angles. The purpose of the present invention is to provide a brushless motor drive device that can reliably stop rotation at a specified angle.

Means for Solving the Problems In order to achieve this object, the brushless motor drive device of the present invention includes a current drive means for passing current through each coil of the stator, and a timing for passing current through the coils using the current drive means. a timing control means for controlling the period during which the timing control is performed; a synchronization clock signal generation means for generating a synchronization clock signal for synchronizing the operation of the timing control means at a predetermined timing; a clock count means for counting the synchronization clock signal; A detection means for detecting that the output of the counting means is a predetermined count number, and a synchronized clock signal at the time when the detection means detects that the output of the clock counting means has reached the predetermined count number based on the output of the detection means. The output of the timing control means is held for a predetermined time based on the predetermined period of time, the output of the timing control means is reset after a predetermined time, and when there is no signal from the detection means, a signal is sent to the timing control means to neutralize the signal of the timing control means. The configuration is equipped with a halt/reset means for giving.

Effect: With this configuration, the brushless motor can be synchronized with a synchronous clock signal to operate like a stepping motor, and the clock counting means, detection means, and hold/reset means ensure that it stops at a specified angle. be able to.

EXAMPLE An example of the present invention will be described below with reference to the drawings. FIG. 1 shows a block diagram of a brushless motor drive device according to an embodiment of the present invention. 1st
In the figure, 1 is a synchronous clock signal generation circuit that generates a synchronous clock signal, 2 is a clock counter that counts synchronous clock signals, 3 is a detection circuit that detects that the count output of the clock counter 2 is a predetermined count number, 4 is a timing control circuit that controls the timing and duration of current flowing through each coil of the stator of the brushless motor 7; 6 is a timing control circuit that controls, based on the output of the detection circuit 3, when the count output of the clock counter 2 has reached a predetermined count number; A hold function that holds the output of the timing control circuit 4 for a predetermined period of time based on the synchronized clock and clock signals at the time of detection.
A reset circuit, 6 a current drive circuit that causes current to flow through each coil of the stator, and 7 a brushless motor.

In this example, a three-phase brushless motor is used in which each coil is Y-connected, and the brushless motor is rotated by 16 degrees in one cycle of the synchronous clock signal.
An example will be explained in which the rotation is stopped and maintained at 0° rotation.

Figures 2 (M) and (B) show the current drive circuit and the coil connection of the brushless motor, below, Figure 3 shows the timing control circuit, and Figure 4 shows the clock counter,
The detection circuit and the hold/reset circuit are shown in FIG. 5.C shows the synchronous clock signal waveform, the output waveform of the timing control circuit, and the output waveform of the hold/reset circuit.

Next, the operation of the drive device of this embodiment will be described.

The synchronous clock signal generation circuit 1 shown in FIG. 1 generates the synchronous clock signal shown in FIG. The timing for turning on Q1 to Q6 and the period for turning them on are determined. The coil of the brushless motor is as shown in Figure 2 @)! wired. As shown in FIG. 3, the timing control circuit 4 includes flip-flops 11 to 14 at J-, a D7 reflex circuit 70, and a J circuit 15 to 20°A.
It consists of ND gates 21 to 23 and an inverter 24, and is based on the synchronous clock signal output from the synchronous clock signal generation circuit 1. One period is made up of 6 periods of the synchronous clock signal, and three non-overlapping 3-phase clocks are connected to each other. J- is generated by a flip-flop. Each of the three-phase clocks generated in this way is connected to six D flip-flops, -) block 16.
~20, the outputs delayed based on the synchronous clock signal are φ1, φ2 . φ3. φ4. φ5. It is φ6. The delayed output waveform is shown in FIG. When the current drive circuit 6 is driven by these φ1 to φ6, the brushless motor 7 rotates by 15° in one cycle of the synchronous clock signal.

Further, the timing control circuit 4 holds the output at the falling edge of the synchronous clock signal immediately before the hold signal is inputted by an external hold signal, and resets the output by an external reset signal regardless of the synchronous clock signal. .

By the way, the clock counter 2 starts counting synchronous clock signals based on a count start signal from the outside. Next, the detection circuit 3 counts the synchronized clock signals based on the output of the clock counter 2, and detects when this count reaches a predetermined number. Simultaneously with this detection, the hold/reset circuit 6 outputs a hold signal to the timing control circuit 4, and after a predetermined time, outputs a reset signal to the timing control circuit 4. A circuit diagram of the clock counter 2° detection circuit 3 and the hold/reset circuit 6 in this embodiment is shown in FIG. clock counter 2
consists of flip-flops 41 to 43 in J-, which is reset by the count start signal to start counting, and HA
ND game) 44.45 The detection circuit 3 detects that the synchronous clock signal has been counted for 6 clocks. Based on this signal, a hold reset circuit 6 consisting of an S-R flip-flop 46 and a D flip-flop 47
First, a halt 0 signal is output, and after one cycle of the synchronization signal, a reset signal is output. The above explanation is illustrated in the figure below.
FIG. FIG. 6 shows the outputs φ1 to φ6 of the timing control circuit 4, which determines the drive timing and drive time of each transistor of the current drive circuit 6 for rotating the brushless motor 7 by 16 degrees in one cycle of the synchronous clock. . Furthermore, in Fig. 5, the brushless motor 7 is rotated at 60°.
The waveform is shown when the rotation is further rotated 90' and then held and stopped. That is, after the brushless motor 7 has rotated 60', a count start signal is given to the clock counter 2. The detection circuit 3 detects the count number of the clock counter 2 as 6, that is, the number of clocks of the synchronous clock signal required for the brushless motor 7 to further rotate by 90 degrees. Simultaneously with this detection, the hold/reset circuit 6 outputs a hold signal to the timing control circuit 4. Accordingly, the timing control circuit 4 holds the output at the falling edge of the synchronous clock signal immediately before the halt signal is input. Hold/reset circuit 51
After outputting the ti and hold signals, a set signal is output to the timing control circuit 4 one period after the synchronization clock signal. As a result, all outputs of the timing control circuit 4 are reset. As mentioned above, the brushless motor 7 rotates 90 degrees from the position rotated 60 degrees and stops at the 15o0 position.
Based on the signal, the current flowing through the coil Km of the brushless motor 7 is cut off by a hold and then a reset signal.

In this embodiment, each signal is synchronized at the falling edge of the synchronous clock signal, but it goes without saying that synchronization may be achieved at any point within one period of the synchronous clock signal.

Effects of the Invention As described above, the present invention provides a timing control means for controlling the timing and period of current flowing through each coil of a brushless motor in synchronization with a synchronous clock signal, and a clock for counting the number of clocks of the synchronous clock signal. A counting means, a detecting means for detecting that the counted number is a predetermined count number, and based on the output of the detecting means, the output of the timing control means is held at the time when the detecting means detects the output, and the output is set to a predetermined value. By providing a hold/reset means that outputs a signal that resets the output of the timing control means after a certain period of time, the brushless motor can be synchronized with a synchronous clock signal without detecting the rotor position and can perform step operation like a stepping motor. The rotation can be reliably stopped at a specified angle, and there is no need for an intermediate storage device to store the next step pulse, reducing manufacturing costs. This is an excellent brushless motor drive device.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a brushless motor drive device according to an embodiment of the present invention, Fig. 2 is a circuit diagram showing the current drive circuit and coil connections of the brushless motor, and Fig. 3 is a block diagram of the timing control circuit. , Figure 4 shows the clock counter and detection circuit. A block diagram showing a hold reset circuit, and FIG. 5 is a synchronous clock signal waveform in an embodiment of the present invention. A waveform diagram showing the output waveforms of the timing control circuit and the output waveforms of the hold/reset circuit, and FIG. 6 is a configuration diagram of a conventional brushless DC motor. 1... Synchronous clock signal generation circuit, 2...
... Clock counter, 3. River... detection circuit, 4...
...Timing control circuit, 6...Hold
Reset circuit, 6...Current drive circuit, 7...
...Brushless motor. Name of agent: Patent attorney Toshio Nakao and one other OJ
Li, 2

Claims (2)

[Claims] (1) A current drive means for passing a current through each coil of the stator, a timing control means for controlling the timing and duration of passing a current through each coil using the current drive means, and a predetermined operation of the timing control means. synchronous clock signal generating means for generating a synchronous clock signal for synchronizing at the timing of , clock counting means for counting the synchronous clock signal from an arbitrary point in time according to an external command, and a count output of the clock counting means is set to a predetermined number of counts. a detection means for detecting that the detection means is based on the synchronous clock signal at the time when the detection means detects that the output of the clock counting means has reached the predetermined count number based on the output of the detection means; holding the output of the timing control means for a predetermined time, and resetting the output of the timing control means after the predetermined time;
A drive device for a brushless motor, further comprising: hold/reset means for supplying a signal to the timing control means that causes the output of the timing control means to pass when there is no signal from the detection means. (2) The timing control means controls the timing and duration of the current to be applied to each coil of the stator in order to rotate the rotor by a predetermined angle in one cycle of the synchronization clock, based on the synchronization clock signal that is the output of the synchronization clock signal generation means. 2. The brushless motor drive device according to claim 1, wherein the timing control means outputs, holds, and resets the timing control means based on an external signal.