JPS59139885A - Brushless motor - Google Patents

Abstract

PURPOSE:To eliminate the torque loss and abnormal vibration of a brushless motor by controlling via a switching mode power source the collector vs. emitter voltage so that an output transistor may always have the prescribed current amplification factor capable of being predetermined by a reisitor. CONSTITUTION:Assume that the only transistor Q1 of output transistors Q1-Q3 is conducted by the positional relation between a rotor 1 and an armature winding 3. Since the hFE of the Q1 varies in response to the collector vs. emitter voltage VCE, the VCE of the Q1 when the loop gain of a negative feedback loop via a differential amplifier 13, a low pass filter 14, a switching mode power source 15, windings L1, Q1, and resistor 7 are sufficiently high are automatically determined, the hFE of the Q1 becomes constant. When the torque command voltage varies, the emitter current of the Q1 alters, and the VCE of the Q1 is automatically varied. Since the hFE of the Q1 is maintained at constant value, the Q1 is not saturated, but maintains the operating state of minimum power consumption.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to a brushless motor that can be used in tape recorders, recorders, hiteo tape recorders, and the like.

Conventional Structure and Problems Fragileless motors, in which the armature current is switched by transistors and the generated torque is controlled manually, are widely used in the above-mentioned industrial fields. FIG. 1 shows a conventional example of a typical configuration using three armature windings.

In Figure 1, a multi-pole magnetized permanent magnet rotor (1)
The rotational position of each winding of the armature winding (3) and ~L3 is detected by the position detector (2) and transmitted to the position irj switching circuit (5). The position signal switching circuit (5) has a 3-differential configuration, with each collector connected to each transistor Q1 to Q3 of the corresponding output transistor group (6).
Connected to the pace of. Output transistor group (6)
The emitters are connected in common, and the collectors are ii
They are each connected to one end of the corresponding phase of the T-Isogo winding (3). Together with the output transistor group (6)! The emitter is grounded via a resistor (7). The voltage at the ungrounded terminal (9) of the resistor (7) is applied to the inverting input (-) of the differential output type pure amplifier circuit (4), and
4) Non-inverting input (+) ij: Torque command voltage (8) is applied, and the output of the differential amplifier W6 (4) is applied to the signal switching circuit (5) in the form of a current mirror. The other ends of the armature windings (3) are commonly connected to the power source CIQ.

The operation of FIG. 1 will now be explained assuming that transistor Q is in a conductive state. The armature current flows through the path of winding L1 → transistor Q1 → resistor (7), and the terminal of resistor (7) (
The voltage generated at the torque command input terminal (8) is compared with the torque command input terminal (8), and automatically controlled by a negative feedback circuit so that the two become equal. As a result, the armature current changes to the torque command voltage (
8). That is, the torque generated by the motor is controlled by the torque command voltage (8).

Further, the power supply voltage is set sufficiently high so as not to saturate the transistor Q1 in order to obtain the required generated torque at the time of motor startup and motor rotation. Here, between the collector and emitter of the transistor Q1, there is a voltage drop from the power supply voltage to the resistor (7), a voltage drop due to the DC resistance of the winding L1, and a back electromotive force and voltage of the winding L1 due to motor rotation. t pressure is applied.

However, when the armature current is small or the motor rotational speed is low, the collector-emitter voltage of the transistor Q becomes 100%, and the power consumption of the transistor Q becomes large, resulting in a large power loss. In addition, if the power supply voltage is lowered, transistor Q1 will become saturated, and at that time, a pace current will flow through transistor Q2 or Q, which should be in the main state, so that the torque generated by the motor will be affected. harmful armature current flows,
This may cause problems such as torque loss or abnormal vibration.

This lack of performance is a major drawback to the miniaturization and low performance of equipment in which brushless motors are used.

Purpose of the Invention The present invention eliminates the above-mentioned drawbacks of the conventional example, and stably prevents saturation of the output transistor, reduces power consumption of the output transistor, and eliminates unstable torque loss and abnormal #R movement. This provides a flangeless motor.

Structure of the Invention The brushless motor of the present invention includes a multi-pole magnetized rotor, a multi-phase armature winding, and a position detection device for detecting the rotational position of the rotor and the electric armature winding. an output transistor group comprising a number of transistors equal to the number of phases that apply a current to the armature winding; a first t current detection means for detecting the current of the current winding;
a first amplifier that makes a difference of 4 between the output signal of the L-flow output means and the torque command input signal; and an output of the first amplifier that is switched according to the output of the position detector, and that is controlled by the output transistor group. a position signal switching means for determining the current phase of the MiJ tun Isogo winding; and a 20' turtle current calculating means for outputting a number 1d corresponding to the base turtle current of the output transistor group;
a second amplifier for amplifying the difference between the respective output signals of the first and second current detecting means; and a switching mode power supply for supplying power to the first winding of the electric machine; The current flowing through the current detection hand sv+- and Aih = r
In order to keep the ratio to the pace current of the two output transistor groups constant, the switching mode of the second amplifier is
It is configured to control the output voltage of the output transistor, and can safely keep the power loss of the output transistor to a minimum, and eliminate unnecessary torque loss and abnormal vibration by preventing saturation of the output transistor. It is.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. Second
The figure shows its configuration. The permanent magnet rotor (1) is magnetized to 8 poles, and the 3-phase constant state winding (3) is a winding wL with -yIM commonly connected to the output of switching mode '11υ.
l, IJ2. It is composed of L12. The rotation position of the rotation position of the rotation position (1) and the Sashinko line (3) is detected by the position detector (2), and is applied as a three-phase signal to the position signal switching circuit w5 (5). The position signal switching circuit (5) has a three-running configuration of i'NP transistors, and the output transistor group (6)
to drive. The output transistor group (6) consists of transistors Q1, Q2, Q3 whose emitters are commonly connected to the current detection resistor (7). The non-inverting side input (→ is connected to the supply terminal of the torque command 'fIL pressure (8)), and the inverting input (→ is the resistance (7
) and the common emitter of the output transistor P (6). Output terminal a'? ) is connected to the common emitter of the position signal switching (b) path (5), and the output terminal (2) is connected to the non-inverting input (e) of the differential amplifier (to) together with a resistor C1υ whose one end is grounded. There is. Inverting input of differential amplifier 0 (→ is resistor (7) and transistor #
(6), and the output is connected to the voltage control input of the switching mode source Qυ via a low-pass filter α.

Next, the operation shown in FIG. 2 will be explained. ``#L armature electronic current switching mode'' flows through the path of #Qθ → winding - (υ → output transistor group (6) → resistor (7), and differential increase 1
The differential input of the differential amplifier circuit (4) is made to be zero by the negative feedback loop composed of the differential amplifier circuit (4), the position signal switching circuit (5), the output transistor group (6), and the resistor (7). She is restrained and moans. 1. /1, depending on the positional relationship between the 1st packing trochanter (1) and armature winding (3), the output transistor Q,
It is assumed that among transistors Q3 and Q3, transistor Q is also in a conductive state. In the resistor [(7) VC, only the emitter current of transistor q1 flows. The pace current ■1 of the transistor Q1 is supplied from the current output terminal qη of the differential amplifier circuit (4), and a current of the same magnitude is also supplied from the current output terminal (6) to the resistor Oυ. The values of the resistor (7), the resistance aυ, and the flowing current are R, R1, and ■7.
■1. Then, the input voltage v13 of the differential amplifier (2) can be written as hIP]1l=7-1...(2), ■,=
111, formula (1) becomes. The hPIC of transistor Q has a collector-emitter' shown in Fig. 3.
Tortoise pressure V. , so the differential amplifier (L3,
Low pass filter <141. Switching mode power supply (
c), Volume 11iilL1, When the loop gain of the negative feedback loop composed of the output transistor Q1 and the resistor (7) is insufficient, the collector-emitter operating voltage of the transistor Q1 is automatically adjusted so that the human voltage v13 becomes zero. It is decided. Therefore, from equation (3), 11 h, B=--1...(4) 7. Since the right side of equation (4) is constant, if the transilk command voltage changes, the emitter current of transistor Q also changes, and from Figure 3, the collector current of transistor Q changes.
The emitter voltage also changes automatically. This voltage is determined by the characteristics of the transistor Q, and is the minimum required voltage to flow a predetermined emitter current.

Furthermore, since hFIll is automatically determined according to device variations and transistor temperature changes and is kept at a constant value, transistor q does not saturate and maintains the operating state with the lowest power consumption. Switching mode voltage (
The output voltage of (to) is equal to the sum of the DC voltage drop due to the DC resistance of winding L1, the collector-emitter voltage of transistor Q1, the voltage drop of resistor (7), and the motor back electromotive force, and is equal to the voltage of power supply 4. The difference between them is the internal loss of the switching mode power supply σθ. However, since the switching mode is ``switching'', the power efficiency is sufficiently high, and the power loss due to changes in armature current or motor rotational speed is much smaller than when using a series control type power source.

In addition, the slope of the filter is a low-pass filter, which improves the stability of the negative feedback loop that connects the differential amplifier.
) and the rotational position of the current winding m(3) change and which of the transistors Q1 to Q3 becomes conductive changes, the operating potential of the transistors Q1 to Q3 corresponds to the winding current with the same operation as described above. and change stably.

In addition, in the above embodiment, a three-phase case was explained, but
The present invention is not necessarily limited to three phases, and various modifications may be made without changing the spirit of the present invention (for example, a position signal switching circuit (5 phase
), and increase the value of the resistor (B) by an amount corresponding to the amplification factor, or set the current ratio of the current output terminal 0□□□9η to a value other than 1. There are countless applications such as methods for changing the value of the resistor Q7).

As described in detail of the invention, the brushless smoker of the present invention controls the collector-emitter voltage with a switching mode power supply so that the output transistor has a constant current amplification factor V which can be predetermined with a resistor. By suppressing the power loss of the output transistor to the necessary minimum and preventing saturation of the output transistor, unnecessary torque loss and abnormal vibration can be eliminated. In addition, since the collector-emitter operating voltage of the output transistor automatically follows the regulator variation, operating current, or transistor temperature, a healthy and stable operation can be obtained. Therefore, the size of brushless motor convenience equipment, low oil *'fM,
It is particularly effective for empowerment.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional example of a brushless morph, FIG. 2 is a block diagram of an embodiment of the present invention, and FIG. 3 is a graph showing the relationship between collector-emitter spiral pressure and current amplification factor of a transistor. (υ...rotor, (2)...position detector, (3)...
... Armature winding, (4) ... Differential amplifier circuit, (5) ...
...Position signal switching circuit, (6)...Output transistor group, (7)συ...Resistor, (8)...Torque command human power voltage, a3...Differential amplifier, a4)... Filter, αυ...Switching mode power supply agent Yoshihiro MorimotoFigure 1

Claims (1)

[Scope of Claims] 1. A multi-polar magnetized permanent magnet rotor, a multi-phase single armature winding, and a position detector that detects the rotational position of the rotor and the armature winding; an output transistor group including a number of transistors equal to the number of phases that apply a current to the armature winding; a first current detection means for detecting the current in the armature winding; and the first current detection means. a first amplifier that amplifies the difference between the output signal and the torque command input signal;
position signal switching means for switching the output of the first increaser according to the output of the position detector and determining the energization phase of the ridge-isolated winding by the output transistor group; and a base of the output transistor group. 'A second current detection means that outputs a signal according to the adverse current, a second amplifier that increases the difference between the outputs of 1g of each of the first and second current detection means, and a switching mode power supply for supplying power to the Isogo winding; 2. A brushless motor configured to control the output voltage of the switching mode power supply by using a current mirror and a resistor as the second current detection means, a current output type differential amplifier as the first amplifier, and controlling the output voltage of the switching mode power supply. Claim 1: The current mirror distributes the output between the position signal switch and the resistor, and the voltage across the resistor is used as the output of the second current detecting means. 3. The brushless motor according to claim 1, further comprising a low-pass filter inserted between the second amplifier and the switching mode power supply.