JPH04185296A - Dc brushless motor controller - Google Patents

Abstract

PURPOSE:To commutate currents applied to stator windings always at the most appropriate position by a method wherein a varying means which varies the timing of position detection signals in accordance with the revolution of a rotor and the currents of the stator windings is provided. CONSTITUTION:A three-phase logic circuit 1 generates commutation position signals for the respective windings 7, 8 and 9 of a stator in accordance with the respective position signals of a rotor given by Hall sensors 10, 11 and 12. The commutation position signals are inputted to a lead angle adjusting circuit 2 and, after the commutation timing its adjusted, the powers of the commutation position signals are amplified by a power drive circuit 5 to drive the stator windings. Two factors with which the lead angle adjusting circuit 2 adjusts the timing are stator winding current information obtained by motor current detectors 4, 5 and 6 and rotor revolution information obtained by the Hall sensors. The required data processing is performed in the lead angle adjusting circuit 2. With this constitution, even if a motor revolution is varied and a load torque is varied, the most appropriate commutation timing can be always obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control device for optimizing the timing of commutation to the stator windings of a DC brushless motor.

[Conventional technology]

A position detection signal for a rotor composed of permanent magnets is generally generated using a position detection device such as a Hall sensor to obtain a predetermined commutation timing of the stator winding. By the way, the timing of commutation to the stator windings needs to be adjusted due to the effects of current delays due to the inductance of the windings and bias in the composite magnetic field due to armature reaction caused by current flowing through the stator windings. there were. Conventionally, the optimum position has been achieved by mechanically adjusting the position of the rotor's position detecting device or electrically adjusting the output signal of the position detecting device.

[Problem that the invention attempts to solve]

However, if the rotor rotation speed is variable, or if the motor load is variable and the stator winding current changes, the output signal of the position detection device that should have been adjusted to the optimal position may also be adjusted to the optimal position. As a result, there were problems such as deterioration of motor efficiency and startup failure.

The present invention solves these problems in the prior art, and its purpose is to always maintain the optimum position even if the rotor rotational speed is variable or the stator winding current changes. The present invention provides a control device that performs commutation of an identifer winding.

[Means to solve the problem]

A DC brushless motor control device according to the present invention is a DC brushless motor control device that controls a commutation position to a stator winding based on a rotor position detection signal, the rotational speed of the rotor and the stator winding. The present invention is characterized by comprising variable means for varying the timing of the position detection signal in accordance with the current.

〔Example〕

FIG. 1 shows a block diagram of a control device for a DC brushless motor, which is an embodiment of the present invention. In the figure, a three-phase bipolar motor is used as the DC brushless motor 13, and a Hall sensor 10 is used as the rotor position detection device.
, 11.12 are used. The rotor position signal obtained from the Hall sensor passes through a three-phase logic circuit 1 to produce a commutated position signal to each winding of the stator winding 7°8.9.

The commutation position signal is input to the advance angle adjustment circuit 2 to adjust the commutation timing, and then power is amplified by the power drive circuit 3 to drive the stator winding. The advance angle adjustment circuit 2 performs the following processing. The factor that adjusts the timing in the advance angle adjustment circuit 2 is the motor current detector 4. 5. These are the stator winding current information Mi obtained in step 6 and the rotor rotational speed information obtained from the Hall sensor. The following calculations are performed in the advance angle adjustment circuit 2. The stator winding current information Mi with respect to the advance angle Lai is expressed by equation (1).

La1=Ki*Mi
(1) However, Ki is a proportional coefficient.The rotational speed information with respect to the advance angle Law is expressed by equation (2).

Law=Kw*Mw
(2) However, Kw is a proportional coefficient, and the total advance angle La is the sum of advance angle Lai and advance angle Law.

FIG. 2 shows specific circuits of the advance angle adjustment circuit.

Further, FIG. 3 shows a waveform diagram for explaining the operation for one phase in FIG. 2. As shown in equations (1) and (2) above, the stator winding current information Mi obtained from the motor current detector and the rotational speed information Mw obtained from the speed detector are Ki and Kw, respectively. After passing through multipliers 14 and 15 having proportional coefficients, the signals are added in an adder 16 to obtain the total advance angle value La.

On the other hand, the three-phase position signal 101. obtained from the Hall sensor.
102 and 103 pass through sawtooth wave generation circuits 17, 18, and 19 and become sawtooth waves 104, 105, and 106, and comparator 20
, 21.22, the total advance angle La is compared with the above-mentioned total advance angle La to be 107°108.109, and the flip-flop is 23°24.
25, a delay amount corresponding to the total advance value La is given to the new three-phase position signals 113, 114, and 115. As can be seen in Fig. 3, in section A where the rotation speed is low and the stator winding current is small, the comparison level of comparators 20, 21, and 22 is low, that is, the advance angle is small, so the delay amount of the three-phase position signal is B with low rotation speed and high stator winding current
In the section, since the comparison level 110 is high, the delay amount of the three-phase position signal is large. Here, the upper limit value and lower limit value of the total advance angle La obtained from the adder 16 are indicated by broken lines 111° and 112. FIG. 4 shows another embodiment of the advance angle adjustment circuit.

Each piece of information obtained from the motor current detector and speed detector 20
1,202 is input to the A/D converter 2'6.27, and becomes a digital signal 203.degree.204, which is input to the CPU28. 3-phase position signal 2 obtained from 3-phase logic circuit 29
05°206.207 is directly input to the CPO28.

In the CPU 28, calculations of equations (1) and (2) are performed and outputs 208, 209, and 210. Although the direct current brushless motor control device of the present invention can be expected to be effective for all types of motors, the effects of the present invention can be expected to be most effective in a structure in which an iron piece is provided around the outer periphery of the magnet to prevent the magnet from scattering. Fields of application of the present invention include small motors that require fine adjustment of the advance angle, ultra-high speed rotating motors, motors equipped with iron pieces to prevent magnets from scattering, and motors that are always operated at their highest efficiency by adjusting the advance angle. electric vehicle motors, etc. Further, in the present invention, an example has been shown in which advance angle control is automatically performed based on various information, but it is also possible to control the advance angle adjustment circuit from outside in order to eliminate the need for mechanical position adjustment.

〔Effect of the invention〕

According to the present invention, since advance angle control is performed based on information from two systems: rotation speed and current, even if the motor rotation speed is used at variable speed or the load torque is varied, the advance angle is always controlled. The optimum commutation timing has been obtained, making it possible to use the motor at its highest efficiency. Furthermore, in terms of starting characteristics, by adjusting the advance angle, stable starting performance was always obtained, and reliability was greatly improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a DC brushless motor control device that is an embodiment of the present invention. FIG. 2 is a specific circuit diagram of the advance angle adjustment circuit shown in FIG. 1. FIG. 3 is a waveform diagram for explaining the operation of FIG. 2. FIG. 4 is a block diagram showing another embodiment of the advance angle adjustment circuit. 1--------3-phase logic circuit 2--
−−−−−−−−1 Advance angle adjustment circuit 3−−−−−
-------- Power drive circuit 4, 5. 6--
------ Motor current detector 7, 8. 9---
---1 Stator winding 10, 11. 12-
−−− Hall sensor 13−−−−−−−−−−1 DC brushless motor or more Applicant Seiko Epson Corporation

Claims (1)

[Claims] In a DC brushless motor control device that controls a commutation position to a stator winding based on a rotor position detection signal, the position detection signal is controlled according to the rotational speed of the rotor and the current in the stator winding. A direct current brushless motor control device characterized by comprising variable means for varying timing.