JPH0622588A - Controller for brushless motor - Google Patents

Abstract

PURPOSE:To rapidly stop a brushless motor at a predetermined position and to start to rotate it in a predetermined direction. CONSTITUTION:When a signal of a rotation signal terminal 3 becomes a low level and a motor is stopped, a special phase of three-phase windings 16a-16c is conducted by a timer 10 for a predetermined time to brake a rotor 17 to stop it. At the time of nest starting, sequential drive pulses for driving the phases of the windings 16a-16c are applied by a start pulse forming circuit 4, and the rotor 17 is rapidly rotatably driven by an initial driving pulse in a predetermined rotating direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a half-wave control brushless motor control braking and starting device.

[0002]

2. Description of the Related Art For example, when a general DC motor is used in a variable valve timing device for an automobile, a set load of a brush of the DC motor must be increased in order to avoid an adverse effect due to engine vibration caused by direct mounting of the engine. However, the wear of the brush is increased and the life is shortened. Therefore, there is a need for a so-called brushless motor that eliminates brushes, and requires only three switching elements.
The adoption of a phase-half wave control type brushless motor is being studied (for example, JP-A-57-173385).

[0003]

However, quick braking and startability are required in the positioning control that requires frequent interruptions peculiar to the variable valve timing device.
First, regarding the braking property, in the case of the three-phase full-wave control method that requires six switching elements, if all the switches on the high potential side are turned off and all the switches on the low potential side are turned on, the winding of each phase The wire can be short-circuited and can be easily braked, but for example, in the case of the three-phase half-wave control method in which the number of switching elements is half, the winding cannot be short-circuited, and thus such braking is not possible. There was a problem.

Regarding the startability, good startability can be expected in the case of a brushless motor with a position sensor, but in the case of a sensorless type brushless motor without a position sensor, the position of the rotor at start-up can be known. Therefore, even if a sequential drive pulse that drives each phase from the outside is given to start it, depending on the position where the rotor is stopped, it may temporarily turn in the opposite direction by the first drive pulse, There was a big problem that the startup time became long.

Therefore, an object of the present invention is to be able to promptly stop at a predetermined rotor position and to promptly start rotation in a predetermined direction.

[0006]

Therefore, the present invention has a plurality of phases of stator windings and rotors, and sequentially supplies drive pulses to each of the stator windings from only one direction to drive the rotors. A controller for a brushless motor of a half-wave control method for rotating, comprising: stop pulse generating means for energizing a specific phase for a predetermined time when the rotor is stopped; and a specific phase energized for a predetermined time when stopped at start-up. And a starting pulse creating means for applying a sequential drive pulse to each of the fixed windings from the phase to be excited next.

[0007]

As a result, when the brushless motor is stopped, the stop pulse generating means energizes the specific phase for a predetermined time to brake and stop the rotor, and the rotor is driven by the detent torque of the permanent magnet until the next start. It is stopped at a specific position. Therefore, since the position of the rotor can be recognized during the stop, the rotor is promptly driven by the first drive pulse at the time of starting from the start pulse creating means that gives a sequential drive pulse for driving each phase from the outside. It is driven to rotate in a predetermined rotation direction.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the block diagram shown in FIG. 1 and the operation waveform diagram shown in FIG.

Reference numeral 1 is a positive terminal of the DC power source, and 2 is a ground terminal of the DC power source. A rotation signal terminal 3 rotates when a high level signal is input to the rotation signal terminal 3, and stops when a low level signal is input. Reference numeral 4 is a start pulse creating circuit which forms a start pulse creating means for creating a pulse at the time of starting, and is shown in FIGS.
A sequential drive pulse as shown in (1) is generated to sequentially energize and start the U, V, and W phases described later.

AND circuits 5a, 5b and 5c, and 6a and 6c
b and 6c are OR circuits, 7a, 7b and 7c are AND circuits, and 8 and 9 are NOT circuits. Reference numeral 10 is a timer circuit that outputs a pulse signal for a predetermined time: Tc when a high output level of the NOT circuit 9, that is, a low level is input to the rotation signal terminal 3, and 11 is an OR circuit. And N
The OT circuit 9, the timer circuit 10 and the OR circuit 11 constitute stop pulse generating means.

Reference numeral 12 is a commutation timing detection circuit, which generates an induced voltage generated in each of the three-phase stator windings 16a, 16b, 16c of the motor in accordance with the rotation of the rotor 17 of the motor at a predetermined trigger level: Vth. By triggering with, a function of detecting the energization start timing and blocking the energization of the phase that has been energized up to that point when the induced voltage of the next energized phase is triggered according to a predetermined order is provided.

Reference numeral 13 denotes a start-up detection circuit which, when the induced voltage generated in each of the three-phase windings 16a, 16b and 16c exceeds a predetermined value, recognizes that the start-up has occurred and generates an output, and the NOT circuit 8 AND circuits 5a, 5b, 5c via
The output of is set to the low level and the supply of the start pulse is stopped.
An output drive circuit 14 drives the power MOS transistors 15a, 15b, 15c. And 16
Reference numerals a, 16b, 16c are U, V, W three-phase stator windings of the motor, and 17 is a permanent magnet rotor of the motor.

Next, the embodiment of the present invention described above will be explained with reference to the operation waveform diagram shown in FIG. It should be noted that the waveforms of the respective parts shown in FIG. 3 are the operation waveforms of the parts with the same symbols shown in FIG.

First, the case where the motor is rotating normally will be described. The commutation timing detection circuit 12 indicates that the signal at the rotation signal terminal 3 is at a high level and the induced voltage waveform of the U phase shown in FIG. 3C has dropped below Vth at time t1 as the rotor 17 rotates. By the detection by, the energization of the U phase is started via the OR circuit 6a, the AND circuit 7a and the output drive circuit 14. Then, energization of the V phase shown in FIG. 3D is started at time t ₂ and the power MOS is
The transistor 15a is turned off and the U phase current is blocked. Similarly, energization of the W phase is started at time t3 according to the induced voltage waveform of the W phase shown in (e) of FIG.

When the signal at the rotation signal terminal 3 changes to the low level at time t4, the outputs of the AND circuits 7a, 7b, 7c all change to the low level and the NOT circuit 9
The high-level signal inverted by is applied to the timer circuit 10, and the timer circuit 10 generates a high-level timer output for a predetermined time Tc as shown in FIG.
The power MOS transistor 15c is input to the R circuit 11 and is turned on through the output drive circuit 14 for a predetermined time Tc.

Therefore, when the signal at the rotation signal terminal 3 becomes low level, the W phase is provided with a timer output for a predetermined time: Tc. Therefore, the braking force is applied to the rotor 17 by the torque to hold the rotor in the W phase, and the rotor 17 can be quickly stopped at a predetermined position.

Further, when the rotor 17 is restarted, the rotor 17 can be quickly started to rotate in a predetermined rotation direction from a specific stop position without being reversed by the first start pulse by the start pulse generating circuit 4. And the rotor 1
With the start of rotation of 7, the three-phase windings 16a, 16b,
When the induced voltage generated in 16c exceeds a predetermined value, it is detected by the start detection circuit 13 and the outputs of the AND circuits 5a, 5b, 5c are set to low levels via the NOT circuit 8, and the start pulse generation circuit 4 outputs Start pulse is each power M
The supply to the OS transistors 15a, 15b, 15c is blocked, and the operation of the commutation timing detection circuit 12 during normal rotation is started.

[0018]

As described above, according to the present invention, when the brushless motor is stopped, it can be quickly stopped at a specific position by being braked by energization of a specific phase for a predetermined time. There is an excellent effect that the rotation can be promptly started in the predetermined direction by the start of the excitation from the next phase.

[Brief description of drawings]

FIG. 1 is an electric circuit diagram showing an embodiment of the present invention.

FIG. 2 is an output signal waveform diagram of the startup pulse generation circuit in the above embodiment.

FIG. 3 is a waveform chart of each part in the above embodiment.

[Explanation of symbols]

 4 Start-up pulse generation circuit 9 NOT circuit 10 Timer circuit 11 OR circuit 12 Commutation timing detection circuit 13 Start-up detection circuit 16a Stator winding 16b Stator winding 16c Stator winding 17 Rotor

Claims (1)

[Claims] 1. A stator winding having a plurality of phases and a rotor,
A controller for a half-wave control type brushless motor that sequentially supplies drive pulses to each of the stator windings from only one direction to rotate the rotor, and energizes a specific phase for a predetermined time when the rotor is stopped. Stop pulse generation means for performing the above, and start pulse generation means for applying a sequential drive pulse to each fixed winding from a phase excited next to a specific phase energized for a predetermined time at the time of stop at startup. Controller for brushless motor.