JPS59136092A - Brushless motor - Google Patents

Abstract

PURPOSE:To accurately control the torque of a brushless motor by inputting an armature current detected value through a voltage divider to a differential amplifier by a current mirror together with a torque command value and controlling the base of an output transistor by the output of the amplifier. CONSTITUTION:The rotating position of a motor which has a magnet rotor 1 and an armature winding 3 is detected by a detector 2, inputted to switching circuits 5, 7, and connected to output transistors 6, 8 of push-pull configuration. An armature current detected value by a resistor 13 is inputted to a differential amplifier 4 by a current mirror together with a torque command 15 through voltage dividers 23, 24, an output 19 is inputted to the circuit 7, the output 18 is inputted to the circuit 5 through a differential amplifier 20, thereby controlling the transistors 6, 8. Accordingly, the voltage dividers 23, 24 are inserted to a negative feedback circuit to operate the transistors to become constant current amplification factor, and torque control is accurately performed without influence of the armature current and the rotating speed.

Description

[Detailed description of the invention] Industrial applications The present invention is a tape recorder and a record player.

This invention relates to a brushless motor that can be used in video tape recorders, etc.

Conventional configuration and its problems Brushless motors, in which armature current is switched by transistors and generated torque is controlled by command input, are widely used in the above-mentioned industrial fields. A conventional example of a typical configuration using three-phase nQ child windings is shown in FIG.

In Fig. 1, the rotational positions of the multi-pole magnetized permanent magnet rotor (]) and each of the windings L1 to L3 of the armature winding (3) are detected by a position detector (2), and a position signal is detected. The signal is transmitted to the switching circuits (5) and (7). Position signal switching circuit (5)
Each of (7) has a three-differential groove configuration, and the collector of each is connected to the base of each of the transistors Q1 to Q3 and Q4 to Q6 of the corresponding output transistor group ([i) (8).

The output transistor group +6) (8) has its emitters connected in common, and its collectors are connected to each other in a push-pull configuration.
) to one end of the corresponding phase of each. The common emitters of the output transistor group (6) are connected to a power supply θG, and the common emitters of the output transistor group (8) are grounded via a resistor α→. The voltage at the ungrounded terminal α4) of the resistor IJ is connected to the current output type differential circuit (
4), and the torque command ``semi-pressure (15) is applied to the other input of the differential amplifier circuit (4), and the output of the differential amplifier circuit (4) is a position signal in the form of a current mirror. The voltage is applied to the switching circuit (7).The other end of the ?Yu-san Senmakihiru (3) is commonly connected and connected to one input (6) of the difference/auxiliary amplifier circuit (9), and the differential amplifier 1 The other input (lυ) of the differential amplifier circuit (9) is applied with - of the IE voltage of the power supply Ql by the voltage divider αO.The output of the differential amplifier circuit (9) is in the form of a current mirror and is connected to the position signal switching circuit (5). is applied to.

The operation of FIG. 1 will now be described assuming that transistors Q3 and Q4 are in a conductive state. The current '1' flows through the path of transistor Q3 → winding L1 → spring wire L3 → transistor Q4 → resistor (T), the voltage at terminal αΦ and torque command input voltage αQ are compared, and the negative feedback circuit The error is controlled to be zero. As a result, the armature current is controlled by the torque command voltage 0 pupil, and therefore the torque generated by the motor is controlled by the torque command voltage OG. On the other hand, winding L
The common connection point of L, L2, and L3 is a differential amplifier circuit (
9) is maintained at 1/2 of the factory voltage by the negative feedback circuit. Therefore, the first position of the armature winding (3) changes around the value of 1/2 of the power supply voltage, and the transistor Q3
．． Since Q4 operates with almost the same collector-emitter voltage, if the voltage across the winding and L3 increases due to an increase in the torque command voltage or motor rotation speed, transistors Q3 and Q4 will have approximately the same voltage of 4q degrees. saturation is reached,
The utilization rate of power supply voltage is improved.

However, since the armature current is detected as the emitter WIZ current of the transistor Q4 and is compared and suppressed with the torque command voltage α, the collector current changes due to a change in the current amplification factor due to a change in the collector voltage of the transistor Q4. The relationship with the emitter current changes and the armature winding (
3) The relationship between the current flowing in and the torque command voltage changes. In particular, when the transistor Q4 approaches saturation, the current amplification factor decreases and the armature current corresponding to the torque command "i" no longer flows. The above-mentioned disadvantages have been a major drawback when attempting to rotate the motor with constant torque.

OBJECTS OF THE INVENTION The present invention eliminates the drawbacks of the above-mentioned conventional examples, and
To provide a brushless motor suitable for generating accurate torque by making the relationship between the electric current and the torque command voltage constant regardless of the current value.

Structure of the Invention In order to achieve the above object, the present invention includes a multipolar magnetized permanent magnet rotor, a plurality of electric grid windings having one end connected in common, and a combination of the rotor and the armature winding. 1) push-pull output transistor pairs of a number equal to the number of phases connected to each phase of the first armature winding; and M'1 output transistor. a first current detection resistor for detecting the sum of emitter currents of the opposite transistor group; a voltage dividing means for dividing the detected voltage of the first current detecting resistor; and an output signal of the voltage dividing means and a motor torque. an amplifier @1 that amplifies the difference between the command input and the output of the first amplifier according to the output of the position detector; a first position signal switching means that determines the energization phase; a second current detection resistor that generates a fiJ pressure according to the base current of the one transistor group;
a second 'ti'J'@ device that amplifies the difference between the peak royal pressures of the first and 1°C2 current detection resistors, and an output of the second amplifier to the output of the position detector; and a second position signal switching means for determining the energization phase of the armature winding by the other transistor group of the output transistor pair, the base current of the one transistor group and the first The conduction state of the other transistor group is controlled by the second amplifier so that the ratio with the 1E current flowing through the current detection resistor is maintained at a constant value K, and the voltage dividing ratio of the voltage dividing means is set to □1-. It is configured to generate a torque according to the torque command input, thereby controlling the torque by detecting the armature/LC flow and comparing it with the torque command input, and also controlling the output transistor related to current control. Accurate armature current control is achieved by a voltage divider 33 inserted between the armature current detection resistor and the differential amplifier circuit in order to keep the operating current amplification factor constant and correct the relationship between collector current and emitter current. It is something that can be done.

DESCRIPTION OF EMBODIMENTS An example of a field according to the present invention will be described below based on the drawings. Second
The figure shows its configuration. The permanent magnet rotor (]) is magnetized into 8 poles, and the 3-phase triplex winding (3) is composed of windings L+, L2, and I-3 that are commonly connected at one end.

The rotational positions of the rotor (1) and armature winding (3) are detected by a position detector (2) and applied as a three-phase signal to the position (word switching circuit (5) and (7). Signal switching circuit (
5) is a three-difference @groove configuration using NPN transistors to drive the output transistor group (6). Position signal switching circuit (7
) drives the output transistor group (8) with three differential borrowings using PNP transistors. Output transistor group (6
) consists of PNP transistors Ql, Q2, Q3 whose emitters are commonly connected to the power supply α→, and the output transistor group (8) has its emitters commonly connected to a current detection resistor (1
NPN I-transistors Q4 and Qs connected to the
, Qs. Transistors Q1 and Q4. Q2 and Qs, Q3 and Qs have a push-pull configuration, and their collectors have common windings L3, L2, t, respectively.

connected to. A torque command voltage O5 is applied to the non-inverting side input (G) of the differential amplifier circuit (4) having two current output terminals (7) α by a current mirror, and a resistor (13 The voltage is divided by a voltage divider consisting of one resistor (C) and the voltage is applied to the output terminal A.
7), and the output terminal (to) is connected to the non-inverting input of the differential amplifier (a) together with a resistor θ, one end of which is grounded. Differential amplifier? ) is connected to the ungrounded side of resistor 03, and the output is connected to the position signal switching circuit (5) via a low-pass filter j]).
is connected to the emitter of

Next, circuit operation will be explained. The armature current flows through the output transistor group (6) -> the dotted line (3) -> the output transistor group (8) - the resistor (14), and passes through the differential amplifier circuit (4).
) 2nd place ml signal switching circuit (7), output transistor group (
8).

A negative feedback loop constituted by the resistor 03 controls the differential power of the differential amplifier circuit (4) to zero.

Assume now that only transistors Q3 and Q4 of the output transistor Ql-06 are in the 4-way state due to the positional relationship between the rotor (1) and the armature winding (3). Only the current flowing through the resistor α flows through the transistor.

The base current I4 of the transistor Q4 is supplied from the current output terminal α of the differential amplifier (4), and the same current is supplied from the current output terminal (ia) to the resistor αη. If the a field, the value of the resistance αη, and the flowing current value are R13, R17, I13, and 117, respectively, the input voltage V20 of the differential amplifier 1 is V2O = R17・117 R13・113
− (1) and I4”117, so the formula (
1) becomes. The hFE of the transistor Q4 has a collector-emitter voltage ■ as shown in FIG. . , the differential amplifier (A), the low-pass filter Qυ2 position signal switching circuit (5), and the output transistor Ql1 winding L1° and L3 . Output transistor Q4. When the loop gain of the negative feedback loop constituted by the resistor 04 is sufficiently high, the collector-emitter operating voltage of the transistor Q4 is automatically determined so that the input voltage V20 becomes zero.

Therefore, the equation becomes 3. Since the right side of equation (4) is constant, when the transilk command voltage changes, the emitter current of transistor Q4 also changes, and from FIG. 3, the collector-emitter voltage of transistor Q4 also changes automatically. In other words, since the collector-emitter voltage of the transistor Q4 (i' is automatically controlled according to the current) so that the commercial flow rate is kept constant, the voltage of the windings Ll and L3 is The potential at both ends is also determined corresponding to the electron current 1-d, and stable operation is achieved.

The resistance values of resistor 4 and resistor (c) are R23 and R24, respectively.
, the 4 IEs (IQ and I) of the non-inverting side input (1) and the inverting side input (c) of the differential amplifier circuit (4) are set to V1, respectively.
5, V22, so that it becomes . Furthermore, if the collector current of transistor Q4, that is, the current flowing through the armature winding (3) is Ia, then V15 V22 '' 0
...(8) holds true.

From the above formula. This means that the current Ia, which flows through the armature winding (3) and contributes to torque generation, resists the torque command input voltage V16 (
This means that the generated torque can be easily and accurately controlled by the torque command input voltage. As the motor rotates, the rotational positions of the rotor (1) and m armature winding (3) change,
Even if the conductive transistor among the transistors Q1 to Q6 changes, the winding is performed in the same manner as described above.
, L3 changes stably in response to the flow of winding 2E.

In addition, in the above embodiment, a three-phase case was explained, but
Naturally, the present invention is not necessarily limited to three phases, and various modifications (for example, position signal switching circuits) can be made without changing the spirit of the present invention.
7 and the output transistor group (8), and increase the value of the resistor 0 by an amount corresponding to the amplification factor, or the current of the current output terminal a→αe. Needless to say, there are many applications, such as a method of changing the value of the resistance αη by setting the ratio to a value other than 1.

As described in detail, the brushless motor of the present invention operates the output transistor so that it always has a constant IE current amplification factor that can be predetermined by the resistance ratio, and inserts a voltage divider in the negative feedback path to control the armature. The generated torque can be controlled without being affected by the magnitude of the current or the motor rotation speed, and is extremely effective when operating a brushless motor at a constant torque.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram of a conventional example of a brushless motor, Figure 2 is a diagram of an embodiment of the present invention (which can be constructed), and Figure 3 is a graph showing the relationship between the collector-emitter voltage of a transistor and the iW current amplification factor. (1)...rotor, (2)...position detector, (3)
...' Single coil winding, (4)...Differential amplifier circuit, (5
) (7)...position signal switching circuit, (())(8)...
・Output transistor group, Q4αη...resistance, (+@・
・Torque command input voltage, OQ...Power supply, (A) ・Differential amplifier, eυ...Filter, (G) (To)...Voltage divider agent Yoshihiro Morimoto

Claims (1)

[Scope of Claims] 1. A permanent magnet rotor set in a permanent magnet rotor, a multi-phase armature winding whose one end is commonly connected, the rotor and the dragon (
゛A detector for detecting the rotational position of the armature winding, and a pair of push-pull output transistors connected to each phase of the armature winding and connected to +AtJ, which is equal to the number of phases. a 10' current flow detection resistor for detecting the sum of emitter currents of the negative transistor group of the output transistor pair; voltage dividing means for dividing the detected Iq voltage of the first current detection resistor; a first amplifier for increasing the difference between the output signal of the voltage dividing means and the motor torque command input;
1) determining an energization phase of the armature winding by the one transistor group of the M output transistor pairs;
amplifying the difference between the detected upper voltages of the position signal switching means, the second current detection resistor that generates a voltage according to the base current of the one transistor group, and the first and second current detection resistors; and the second amplifier of Q'U;
: Gate type output switch according to the output of the position detector,
and a second position signal switching means for determining the energization phase of the armature winding by the other transistor group of the output transistor pair, the base current of the one transistor group and the tenth tributary current. The conduction state of the other transistor group is controlled by the second amplifier so as to maintain the ratio of the current flowing through the detection resistor to a constant value 1<((ii)
The brushless motor is heated so that the partial pressure ratio of the pressure dividing means is set to □, and a torque is generated in response to a command input to the torque finger 1-.