JPS59198891A - Drive circuit of motor - Google Patents

Abstract

PURPOSE:To control a motor in a high efficiency with a simple configuration by controlling a rotating speed by a rotating position detection signal of the motor and a signal formed of the detection signal and capable of controlling duty ratio formed of the level variable control voltage. CONSTITUTION:The rotating position of a motor M is detected by Hall elements H1-H3, inputted to a logic circuit 2, inputted to a zero-cross detector 4 to obtain a pulse PD corresponding to the zero-cross position, and a sawtooth wave signal VS from a function generator 5 is inputted to a comparator 6. A level variable control voltage VC is inputted to the other terminal of the comparator 6, the output and an output of the logic circuit 2 are processed by AND circuits 7-9, thereby controlling the energization of motor coils L1-L3 through a drive circuit 11. Accordingly, the energizing time and order to a motor coil L is controlled by the regulation of the control voltage VC, and the control having less power loss is executed in a simple structure.

Description

[Detailed description of the invention] 〔Technical field〕 The present invention relates to a motor control circuit.

[Background technology]

For example, a brushless motor control method includes a method of supplying a control current proportional to a control voltage to a motor coil. Another method is to control the power supply voltage supplied to the motor coil intermittently.

Prior to the invention of the present application, the present inventor has investigated that the first control method has poor control efficiency, and the second control method requires not only a transistor for a power switch, but also a coil and a capacitor. It turned out that a filter circuit consisting of Furthermore, in the second control method, the power supply is switched on and off at high speed;
It was also revealed that unnecessary opening occurs due to the switching frequency (about IOKHZ).

[Purpose of the invention]

An object of the present invention is to provide a motor control circuit that has a simple circuit configuration and is capable of controlling sieve efficiency.

c'iqn Overview] Among the two inventions disclosed in this application, a brief overview of typical ones is as follows. In other words, a rotational position detection signal and a pulse signal for controlling the rotational speed of the motor by the data ratio are obtained from the output signal of the motor rotational position replacement element, and the above detection signal and pulse signal are combined. This allows the motor coil to be energized intermittently, thereby achieving the object of the present invention, which is high efficiency control.

[Embodiment 1] Hereinafter, an embodiment of a motor control circuit to which the present invention is applied will be described with reference to FIGS. 1 and 2.

It is assumed that the motor control circuit 1 shown in FIG. 1 is constituted by a semiconductor integrated circuit (hereinafter referred to as IC).

Hall elements H, , H, , H8 detect the rotational position of the rotor constituting the motor. When the motor M is a three-phase motor, each Hall element H,,H,.

The mounting position of H8 is output signal Hv□, HV□, Hv3
are provided on the stator side so that the phase difference is 120°.

Each output signal Hv l'v Hy 2y Hv s'ma・
They are supplied to Hall amplifiers A, , A2', and A, respectively. Each hall amplifier A,,A2. A, output signals Uv, V
,.

The signals are supplied to the next stage logic circuit 2 with a phase difference of 120°. Furthermore, the output signal Uv, 7. Wv is also supplied to the zero cross position detection circuit 4 as a signal for controlling the rotational speed of the motor.

The zero-cross detection circuit 4 detects the zero-cross position of the output signal Uv, ■7°W. Then, the pulse signal PD corresponding to the zero cross position as shown in FIG. 2(E) is supplied to the function generating circuit 5 at the next stage. The integrating circuit 5 synchronizes with the pulse signal PD as shown in FIG. 2(F).
Obtain a sawtooth signal ① as shown in . Note that the function generating circuit 5 may be composed of a switching transistor that is turned on by the pulse signal PD, and a capacitor that performs photoelectric and discharge.

The above-mentioned sawtooth signal ◯ is supplied to the input terminal ◯ of the voltage comparator circuit 6. The input terminal ■ of the voltage comparator circuit 6 has a control voltage ■. is supplied. Control voltage V. The voltage levels of V, , and V are shown in Figure 2 (F).

As shown, it can be arbitrarily varied.

Therefore, the control voltage V. When is set to level ■, voltage comparator 6 generates a signal corresponding to the time from the rise of sawtooth signal ■5 to the intersection with control voltage ■1, as shown by the solid line in Figure 2 (G). An output signal P with a pulse width is obtained. Also, the control room pressure V. When is varied to level v2, the pulse width of the output signal PC corresponds to the time from the rise of the sawtooth signal V to the intersection with the control voltage ■2, as shown by the dotted line in Figure 2 (G). The pulse width changes to the specified pulse width. That is, the control voltage V. The voltage change is the pulse signal P. In other words, the output signal P. is converted into a change in the duty ratio. And the pulse signal P.

, that is, the rotational speed control signal is output from AND circuits 7, 8.9
are respectively supplied to each input terminal.

On the other hand, the logic circuit 2 which generates high-level and low-level signals at the output of the circuit 2 outputs the above-mentioned output signal Uv.

Detects changes in the voltage levels of vv and Wv. Taking the output signal U as an example, the output signal Uθ is obtained in a phase period from 0° to 120°. Similarly, a high level output signal Uθ is obtained from the logic circuit 2 in response to the output signal 7, and a high level output signal W is obtained in response to the output signal Wv.

Note that the output signals U, , V, , W determine the order and direction of energization of the motor coils L, , Lt, L, which will be described later. The output signals U, , V, , w are sequentially supplied to each AND circuit 7, 8.9. Therefore, an H level voltage is always supplied to the input terminal a of any one of the AND circuits 7, 8.9.

Below, the output signal Uv and the pulse signal P. Regarding this, the AND circuit 7 transmits the signal U, & its output only during the period when the pulse P0 is at the 1 level. Therefore, the duty ratio of the output signal Pv, which determines whether the motor coil is energized by adjusting the voltage level (2), is the control voltage (2). will be controlled by.

The above-described circuit operation is similarly performed for the AND circuit 8.9, and output signals Pw'Pv'PU are supplied to the drive circuit 11.

Although not shown, the drive circuit 11 actually includes a logic circuit in its manual section, and receives a signal Uθ.

This logic circuit executes various logic processes for V, ,W, ,PU, Pv, and Pw.

Furthermore, the three outputs of the drive circuit 11 'r, j 'r,
A push-pull output stage consisting of a PNP output transistor and an NPN output transistor is arranged in each IT3, and the output signal of the aforementioned logic circuit (not shown) is applied to the base electrodes of these output transistors.

In this way, the output 'i' of the drive circuit 11, t T
From 2vT3, output voltage waveforms as shown in FIG. 2 (CB) and (CL (D)) are obtained, respectively.

Therefore, at time t, a positive level output signal as shown in FIG. 2(B) is obtained from the output T1, and a negative level output signal as shown in FIG. 2(C) is obtained from the output T! When obtained, current flows through the motor coils L1 and L2 in the direction shown by arrow 21 in FIG. Also time 1. Immediately after is terminal T, ,
The potential of T becomes zero level. Then, the energization time t1 is a pulse signal P shown in FIG. 2 (CG). controlled by That is, FIGS. 2(CB), (C), and (CD) show a state where time t is the maximum, in other words, a state where the duty is 100%.

Thereafter, similarly, the current flow time T of the current indicated by the arrow 22 during time t is similarly controlled by the pulse signal P.sub.2. Further, the current indicated by the arrow 23 during time t3 is also the pulse signal P. The energization time T is controlled by. The thick mud shown by arrow 24 is controlled at energization time t4,
The current shown by the arrow 25 is controlled during the current application time tIl, and the current shown by the arrow 26 is controlled during the current application time t6.

As mentioned above, the control voltage ■. is adjusted from vl to V, the above 11 to 10 hours are controlled as shown by the dotted line in FIG. Rotational speed control is thereby performed.

Therefore, in the motor control circuit to which the present invention is applied, the order in which the motor coils are energized and the rotational speed are controlled based on the motor rotational position detection signal.

Further, according to the above control circuit, the output transistor of the drive circuit 1 performs a switching operation between the saturation state and the off state, so that power loss is small and high efficiency control can be achieved.

Moreover, the switching frequency is 6 times higher than that of the rotational position detection signal.
Since the frequency is as low as twice (in the case of a three-phase motor), there is little generation of high-frequency noise and there is no adverse effect on other circuits.

[Example-2] Next, a second example of the present invention will be described. Note that in this embodiment, the control voltage V shown in the first embodiment is used. Instead, a voltage signal corresponding to the rotational speed of the motor is supplied.

The circuit configuration of this embodiment is as shown in the signal path indicated by the dotted line in FIG.
It is subscribed by es pit --Els.

31 is a frequency generator, which obtains a frequency signal fM that changes in accordance with the rotational speed of the motor. Frequency generator is
It is supplied to a frequency-voltage converter (hereinafter referred to as F4 converter) 32.

The output signal vf of the F-V converter 32 is the frequency signal f
It changes depending on the frequency of M. As a result, the control voltage ■ is applied to the input terminal of the voltage comparator 60. Output signal Vf instead of
is supplied. Thereafter, the rotational speed of the motor is controlled in accordance with the voltage level of the output signal vf.

[Example-3] Next, a third embodiment of the present invention will be described.

In this embodiment, instead of the frequency generator 31,
An oscillation source e with a variable oscillation frequency is provided.

The oscillation frequency fe is then supplied to the F-■ converter 32. With this configuration, the rotational speed of the motor can be controlled by adjusting the oscillation frequency fe.

〔effect〕

(1) Since the output signal of the Hall element for detecting the rotational position of the motor can be used as the motor rotational position detection signal and the pulse signal that determines the energization time to the motor coil, the energization to the motor coil can be performed. This occurs between the output transistor's saturation and off state, resulting in less power loss and high efficiency control.

(2) There are fewer external parts, making it easier to integrate semiconductor circuits.

The above description has been made based on the embodiments of the invention made by the present inventor, but it goes without saying that the present invention is not limited to the above embodiments, and can be modified in various ways without departing from the gist thereof. do not have.

Further, the connection method of the motor coils LX, L, , L may be a so-called delta connection instead of the star connection described above.

In addition, it is not limited to 3-phase motors, but also single-phase, 2-phase motors, and 3-phase motors.
It can also be applied to polyphase motors with more than one phase.

[Application field]

The present invention provides at least various electronic devices using motors,
It can be applied to industrial machinery, etc.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of a motor control circuit to which the present invention is applied; FIG. 2 is a circuit diagram showing an embodiment of a motor control circuit to which the present invention is applied;
). (G) is a waveform diagram for explaining the circuit operation same as above. H,,H,,H,... Hall element, A,,A,. A3...Hall amplifier, 2...Logic circuit, 4...
Zero cross detection circuit, 5... Integrating circuit, 6... Voltage comparator, 7.8.9-... AND circuit, M-... Motor, PU, PvtPw... Output signal.

Claims (1)

[Claims] 1. A motor rotational position detection signal, and a motor rotational speed control signal whose duty ratio is controlled, which is formed by this rotational position detection signal and a control voltage whose level can be changed.
The patented motor is characterized in that it is configured to control the rotational speed of the motor, and is configured to change the level at a control port of the motor.