JPS63242195A - Dc brushless motor driver - Google Patents

Abstract

PURPOSE:To eliminate a vibration, a noise and the like by providing a commutation sensing circuit for each coil and an applied voltage switching means for switching a coil-applied voltage to a high voltage. CONSTITUTION:A three-phase type DC brushless motor 10 has a structure including three coils 11-1-3 at given intervals and is equipped with rotor-rotational position sensing elements (Hall elements) 12-1-3. Output ends of respective Hall elements 12-1-3 of this motor 10 are connected with a commutation circuit 20 and respective transistors 30-1-6 of a power application control circuit 30 are ON-OFF controlled so that electric current flows in a given direction through a coil 11. This apparatus is also provided with a commutation sensing circuit 50, a one-shot circuit 60 and a coil-applied voltage switching transistor 70. In this case, said sensing circuit 50 generates only one pulse of pulse signal from a current commutating point of each coil to ON-OFF control the switching transistor 70 via the one-shot circuit 60 and an inverter circuit 61. Thus, a high voltage is applied to said coil from immediately after the commutation so that a response to power application is quickened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a drive device for a DC brushless motor suitable for constant speed rotation.

(Prior Art) FIG. 3 is a circuit diagram showing an example of a conventional DC brushless motor drive device. In the figure, a three-phase DC brushless motor 10 has three coils 11-1.
11-2.11-3 is incorporated with one end in common, and current flows in a predetermined direction through any two coils, and by supplying power to these coils, the rotor remains constant. It is designed to rotate in the direction. The motor 10 includes rotational position detection elements such as Hall elements 12-1 and 12-2 for detecting the rotational position of the rotor.
Three Hall elements 12-3 are also provided at regular intervals, and the output ends of each Hall element 12-1 to 12-3 are connected to the commutation circuit 20. The commutation circuit 20 includes each Hall element 12-1 to
Based on the detection signals 81 to S3 of 12-3, a coil that requires energization in order to rotate the rotor in a certain direction is selected, and each transistor of the energization control circuit 30 is controlled so that current flows in a predetermined direction to the selected coil. 31-1゜31-2
．． 31-3.31-4.31-5. '31-〇 is controlled on/off, and the output signal line is connected to each transistor 31-1, 31-2゜3'+-3, 31-4,
It is connected to the base terminals of 31'-5 and 31-6. The energization control circuit 30 has six transistors 31-1 to 31-6 that are switched on/off according to the output of the commutation circuit 20, and has a transistor between the emitter and collector of each transistor 31-1 to 31-6. Diodes 32-1 to 32-6 are connected to the diodes 32-1 to 32-6. Further, the other end of the coil 11-1 is connected between the emitter of the transistor 31-1 and the collector of the transistor 31-2.
The other end of the coil 11-2 is connected between the emitter of the transistor 1-3 and the collector of the transistor 31-4.
Emitter of transistor 31-5 and transistor 31-
The other end of the coil 11-3 is connected to the collector of the coil 11-3. 40 is a DC power supply for supplying power to each coil 11-1 to 11-3.

In the conventional device having such a configuration, each Hall element 12
-1 to 12-3 output signals are 81 in Figure 4 in one cycle.
．． 82 and S3, each coil 11-1 to 11-
The energization state of No. 3 is 11.12 and L3 in the fourth factor.

That is, the commutation circuit 20 connects the transistor 31-1 of the energization control circuit 30 so that current flows from the coil 11-1 to the coil 11-3 at time t1 when the output of the Hall element 12-1 is reversed from negative to positive. 31-6 and turn on the Hall element 1.
The transistors 31-1 and 31-4 of the energization control circuit 30 are turned on so that current flows from the coil 11-1 to the coil 11-2 at the time t2 when the output of the coil 2-3 is reversed from positive to negative.
Time t when the output of the Hall element 12-2 is reversed from negative to positive
3, the transistors 31-5 and 31-4 of the energization control circuit 30 are connected so that current flows from the coil 11-3 to the coil 11-2.
Turn on. Further, at time t4 when the output of the Hall element 12-1 is reversed from positive to negative, the coils 11-3 to 11-
Transistors 31-5 and 31-2 of the energization control circuit 30 are turned on so that current flows to the Hall element 12-3.
At time t5 when the output of coil 11- is reversed from negative to positive,
The energization control circuit 30 allows current to flow from 2 to 11-1.
The energization control circuit 30 turns on transistors 31-3 and 31-5 so that current flows from the coil 11-2 to the coil 11-3 at time t6 when the output of the Hall element 12-2 is reversed from positive to negative. transistors 31-3 and 31-6 are turned on. As described above, each coil 11-1 of the motor 10
By commutating the current flowing through 11-3, the rotor is driven to rotate in a fixed direction.

(@Aspects to be Solved by the Invention) However, this conventional device has the following problems. That is, even if the current between the coils is commutated by the action of the commutation circuit 20 and the corresponding coil is energized, sufficient current does not flow immediately after the commutation, and the electrical time determined by the resistance and inductance of the coil is reduced. Sufficient current finally begins to flow after a delay of a constant time T. For this reason, the torque generated by the motor decreases until a sufficient current flows through the corresponding coil, which may cause problems such as uneven rotation, imaging, and noise in the motor.

Therefore, the present invention can speed up the response to commutation, thereby preventing a decrease in the torque generated by the motor, eliminating problems such as uneven rotation, vibration, and noise of the motor, and enabling stable constant speed rotation at all times. The purpose of the present invention is to provide a DC brushless motor drive device that provides fast locking.

[Structure of the Invention] (Means for Solving the Problems) The present invention detects the rotational position of the motor using a rotational position detection element, detects the output of this detection element, and uses a commutation circuit to determine which position of the motor. In a DC brushless motor drive device that determines whether to energize a coil and drives an energization control circuit using the commutation circuit output to control commutation of each coil, the commutation point of the 'iR current flowing through each coil is determined. The coil includes a commutation detection circuit for detecting the current, and an applied voltage switching means for switching the voltage applied to the coil to a high voltage for an initial predetermined period of time based on the commutation point detection output from the detection circuit.

(Function) By taking such a measure, a high voltage is applied to the corresponding coil for a certain period of time immediately after transfer, so that the M current rises quickly.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a circuit diagram showing the configuration of an embodiment of the present invention,
Components that are the same as those in the conventional configuration shown in FIG. 3 are given the same reference numerals and detailed explanations will be omitted. In FIG. 1, 50 detects the commutation point of the current flowing through each coil of the DC brushless motor 10 from the output of the commutation circuit 20, and immediately after the detection, a pulse signal P
This is a commutation detection circuit that generates only one pulse of
A two-stage logic circuit 51-4, which takes the exclusive OR of the outputs of 1-1 to 51-3, and a logic which takes the exclusive OR of the output of the logic circuit 51 and the integral value of this output. Circuit 51-
It consists of 6. 60 is a one-shot circuit that converts one pulse P from the commutation detection circuit 50 into a pulse signal Q of a constant time width and outputs the same, and this pulse signal Q is inverted by an inverter circuit 61. Thereafter, the voltage applied to the coil is applied to the base terminal of the switching transistor 70 to control whether the transistor 70 is turned on or off. The transistor 70 is turned on when the pulse signal Q from the one-shot circuit 60 is at a high level, and turned off when the pulse signal Q is at a low level. voltage V is applied to the energization control circuit 30, and when it is off, the diode 4
1, only the voltage V of the DC layer 2I40-1 is applied.

Next, the operation of the apparatus of this embodiment will be explained with reference to FIG. Now, each Hall element 12-1゜12-2.1
The detection output of 2-3 is 81.32. in Fig. 2 in one cycle.
83, the commutation circuit 20 uses the transistors 31-1 to 31- of the energization control circuit 30 to commutate the currents flowing through the coils 11-1 to 11-3 of the motor 10, as in the conventional case. Controls the on/off of 6.

On the other hand, the commutation detection circuit 50 detects six commutation points t1 to t6 in one cycle based on the output of the commutation circuit 20, and generates only one pulse of the pulse signal P at each commutation point. The pulse signal P from this commutation detection circuit 50 is transmitted to a one-shot circuit 60.
Here, it is converted into a pulse signal Q having a constant time width T approximately equal to the electrical time constant of each coil 11-1 to 11-3.
applied to the base terminal of Then, the pulse signal Q
When the level is high, DC 1irfi is applied to the energization control circuit 30.
40-1~. ! = 40-2 paralyzing voltage V (e.g. 20
Volt) is applied, and when it is low level, DC 1. l14
Only a voltage V of 0-1 (for example 10 volts) is applied.

Therefore, each transistor 31-1 of the energization control circuit 30
When the current between each coil is commutated by the on/off operation of ~31-6, a high voltage of, for example, 20 V is applied to the energized coil for the pulse width time T of the pulse signal @Q immediately after the commutation.
After the pulse width time has elapsed, a low voltage of, for example, 10 cm is applied. Therefore, since high voltage is applied immediately after commutation,
L1 in Figure 2. L2. As shown by the solid line L3, the response to energization of each coil 11-1 to 11-3 becomes faster, and the rise time until a sufficient current flows is shortened compared to the conventional case shown by the broken line in the figure.

As described above, according to the present embodiment, when the current flowing between the coils 11-1 to 11-3 of the DC brushless motor 10 is commutated, the current flowing between the coils 11-1 to 11-3 is changed immediately after the commutation.
Since a high voltage is applied to the corresponding coil for a time T corresponding to a time constant of 3, the response to energization becomes faster, and a sufficient N current flows through the corresponding coil in a short time. Therefore, there is no risk that the torque generated by the motor 10 will decrease, and problems such as uneven rotation, vibration, and noise of the motor 10 can be reduced. As a result, the rotational speed of the rotor can be stabilized, and accurate constant speed control can be achieved.

Note that the present invention is not limited to the above embodiments.

For example, in the above embodiment, a three-phase DC brushless motor 10 is illustrated, but other types may be used. Further, in the embodiment described above, the commutation point is detected based on the output of the commutation circuit 20, but the commutation point may be detected based on an input signal to the commutation circuit 20.

Furthermore, although the Hall element is used as the rotor rotational position detection element, it goes without saying that other detection elements may be used. It goes without saying that various other modifications can be made without departing from the spirit of the invention.

′ [Effects of the Invention] As detailed above, according to the present invention, by speeding up the response to commutation, it is possible to prevent a decrease in the torque generated by the motor, and to reduce uneven rotation of the motor, imaging, and noise. It is possible to provide a DC brushless morph drive device that can eliminate such problems and always enable stable constant speed rotation.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing the configuration of an embodiment of the present invention, FIG. 2 is a waveform diagram for explaining the operation of the same embodiment, FIG. 3 is a circuit diagram showing the configuration of a conventional example, and FIG. 4 is a waveform diagram for explaining the operation of the conventional example. 10...DC brushless motor, 11-1 to 11-3
... Coil, 12-1 to 12-3 ... Hall element,
20... Commutation circuit, 30... Energization control circuit, 40-
1.40-2... DC power supply, 50... Commutation detection circuit, 60... One-way circuit, 70... Transistor for switching coil applied voltage. Applicant's agent Patent attorney Takehiko Suzue Figure 2 1Q and Figure 3

Claims (1)

[Claims] Detects the rotor rotational position of the motor with a rotational position detection element,
Based on the output of this detection element, a commutation circuit determines which of the coils of the motor should be energized, and the output of the commutation circuit drives an energization control circuit to control the commutation of each coil. The motor drive device includes a commutation detection circuit that detects the commutation point of the current flowing through each coil, and a commutation point detection output from this detection circuit that increases the voltage applied to the coil for an initial predetermined time. 1. A direct current brushless motor drive device comprising applied voltage switching means for switching.