KR930000150Y1 - Brushless dc motor control circuit - Google Patents

Abstract

No content.

Description

Drive Circuit of Brushless DC Motor

1 is a hysteresis characteristic diagram of a Hall element.

2 is a state diagram of an output waveform in which the duty ratio is decreased when using a Hall element.

3 is a DC motor driving circuit of the present invention.

4 is a waveform state diagram showing a reverse rotation torque generation period when using a Hall element.

5 is a specific embodiment of the present invention.

6 is a waveform diagram of each part showing the driving state of the inventive circuit diagram.

* Explanation of symbols for main parts of the drawings

1 stator coil 2 rotor

3: waveform shaping circuit Ic1, Ic2, Ic3: Hall element

4 switching matrix logic 5 motor driving circuit

AU, AV, AW: driver 10: phase detector

AS: analog switch 11: phase shift circuit

12: Reverse torque generation detection circuit AD1, AD2, AD3: And gate

OR1: Oagate 13: switch control circuit

This invention relates to a magneto-type brushless DC motor, which uses a Hall element to detect the rotational position of the rotor and eliminates the reverse torque that occurs in the system that controls the speed of the motor. It relates to a driving circuit.

The Hall element (Hall Ic) is used to detect the magnet position of the rotor in the motor which obtains the rotational torque by the switching current supplied from the driving amplifier according to the rectified signal. However, the duty (DUTY) changes according to the output signal waveform. The output torque is often lowered. This is due to the hysteresis characteristics of the Hall element.

FIG. 1 shows the hysteresis characteristics of the Hall element, and shows a logic state outputted from the Hall element according to the magnetic flux density.

However, the duty ratio is not exactly 50% because the points where the logic levels are located are different according to the N and S poles in which the magnetic flux density increases.

2 shows a state diagram of an output waveform in which the duty ratio is changed when the Hall element is used. The magnetic flux waveforms of the N pole and the S pole generated when the rotor rotates are output as sine waves.

The Hall element sensing the output of the sine wave detects the output of the sine wave and outputs a state signal of H level and L level to detect the speed of the motor, but the Hall element is affected by hysteresis characteristics and temperature characteristics. It is not possible to output the signals of the tuple cycles, so it has a ratio of different lengths (A) and (B).

The present invention aims to solve this problem, and an object of the present invention is to remove the motor's reverse torque phenomenon caused by the characteristics of the Hall element that detects the position of the rotor, and to improve the rotation torque of the motor. It is to provide a driving circuit of a response DC motor.

A feature of this invention for achieving the above object is a stator coil which receives an output of a motor driving circuit to form an induction magnetic field, a rotor which rotates in response to an induction magnetic field of the stator coil, and a magnetic field position of the rotor. A motor circuit comprising a Hall element for sensing and a motor driving circuit connected to an output side of the Hall element and outputting a logically combined signal after shaping a signal input in three phases, between the stator coil and the motor driving circuit. A brush connected to an analog switch for controlling a current applied to the stator coil, and a phase detection unit connected between the Hall element and the analog switch to receive an output signal of the Hall element and detect a phase to control the analog switch It is in the drive circuit of a response DC motor.

Hereinafter, with reference to the accompanying drawings an embodiment of the present invention in detail as follows.

3 shows a DC motor drive circuit diagram of the present invention. The rotor 2 which rotates in response to the induction magnetic field of the stator coil 1 and the Hall elements Ic1, Ic2, and Ic3 which sense the magnetic field position of the rotor 2 are installed at intervals of 120 °. To form a motor.

On the output side of the Hall elements Ic1, Ic2, and Ic3, an output logically combined with respect to a signal in which the waveform wave is input in three phases through the switching matrix logic 4 in the waveform shaping circuit 3 is provided. The motor drive circuit 5 is configured to be output through (AU), (AV), and (AW).

The output side of the motor driving circuit 5 has a configuration connected to the stator coil 1, and this configuration is the same as a general motor driving circuit.

This design constitutes an analog switch (AS) between the stator coil (1) and the motor drive circuit (5), the analog switch (AS) of the Hall elements (Ic1), (Ic2), (Ic3) The amount of direct current applied to the stator coil 1 is controlled under the control of the phase detector 10 which detects the phase by receiving the output signal on the output side.

In this design, the reverse torque state of the motor generated when the output waveform of the Hall element controls the motor out of the 50 ° duty cycle is as follows.

Here, the features of the present invention will be described as a case where the phase detector is not configured.

That is, the Hall elements Ic1, Ic2, and Ic3 detect the detected pulses HU, HV, and HW for three-phase currents with respect to the magnetic flux density generated when the rotor 2 rotates. Will be generated.

At this time, due to the hysteresis characteristics of the Hall element and the temperature change, a shifted portion of the duty cycle is generated, such as a portion hatched by one phase pulse HU of the three phase current, and the three phase pulses HV and HW are Assuming a normal state, the output side voltage of the motor driving circuit 5 of FIG. 3 is output as shown in (U), (V), (W) of FIG. 4, and the shifted part of the duty cycle in (W) is combed. It appears to be reduced.

In the final output of the three-phase output (U), (V), (W) is applied to the motor to rotate the rotor, there is a portion that generates a reverse rotation, such as a hatched portion during rotation torque, This will adversely affect the forward rotation.

Therefore, the present invention has a phase detector 10 as shown in FIG. 3 to solve this problem. The phase detector 10 shifts the phase of the three phases detected by the Hall element by 60 °. ), A reverse torque generation detection circuit 12 which receives the output of the phase shift circuit 11 and detects a time point at which reverse torque is generated, and an analog switch at the reverse torque generation detection circuit 12 when reverse torque is generated. A switch control circuit 13 for blocking the AS).

The analog switch AS is connected between the stator coil 1 constituting the motor and the motor driving circuit 5 to perform a control operation of supplying and interrupting three-phase current supplied to the motor.

5 is a specific implementation circuit diagram of the present invention, and is mainly shown based on the phase detector 10.

The reverse torque generation detection circuit 12 constituting the phase detection unit 10 includes the AND gates AD1, AD2, and AD3 having two inputs, respectively, and the AND gates AD1, AD2, and ( It consists of an OR gate OR1 which synthesizes the output of AD3).

One input terminal of the AND gate (AD1), (AD2), and (AD3) having two input pins is configured to be input in the order of sensing pulses (HU), (HV), and (HW) of the Hall element which is not phase shifted. The other input terminal of the AND gates AD1, AD2, and AD3 is configured to be input in the order of the detection pulses HV ', (HW'), and (HU ') which are phase shifted by 60 degrees.

In the present invention configured as described above, when the rotor rotates in response to the current of the motor driving circuit, the sensing elements HU, (HV), and (HW) having a phase of 180 ° as shown in FIGS. 6a, 6b, and 6c in the Hall element. ) Is the ideal characteristic that the Hall element has a duty cycle of 50 degrees.

However, as described above, the detection pulses HU, HV, and HW shown in FIGS. 6D, 6F, and 6H are generated due to the hysteresis characteristics of the Hall element and the temperature change.

This design makes and compares the pulses HU ', (HV'), and (HW ') by shifting the sensing pulses by 60 °. The waveform of FIG. 6e is compared with the end gate AD1 to generate reverse torque. In the interval, the H level signal is applied to the OR gate OR1.

Similarly, the waveforms of FIGS. 6f and 6g are compared at the AND gate AD2, and the waveforms of FIGS. 6h and 6i are compared at the AND gate AD3. It is applied to the OR gate OR1.

As described above, the OR gate OR1 applies the H level status signal to the switch control circuit 13 at the portion where the original sensed signal overlaps the 60 ° shifted signal.

Therefore, the switch control circuit 13 receives the status signal of the H-zebel and opens the analog switch AS when the reverse torque is generated to cut off the power applied to the motor, thereby preventing the motor from rotating back, thereby improving the performance of the motor. It is.

As described above, this design can prevent the motor's efficiency caused by the output waveform of the shift element of the duty cycle being generated and the reverse torque generated in the motor.

In particular, the present invention has a means for shifting the sensed pulse of the Hall element by 60 ° and comparing it with the original sensed pulse, and the comparing process uses a logical gate element to determine the time when the reverse torque is generated in the motor. It is possible to improve the performance of the motor by blocking the reverse current from being applied to the motor.

Therefore, this design has the effect of preventing the unbalance by the magnetic pole position detecting element and the Hall element in a motor having a rotor magnet having a magnetization pattern of four poles or less in a DM type brushless DC motor.

Claims (2)

The stator coil 1 receives the output of the motor driving circuit 5 to form an induction magnetic field, the rotor 2 rotates in response to the induction magnetic field of the stator coil 1, and senses the magnetic field position of the rotor. Connected to the output elements of the Hall elements Ic1, Ic2, and Ic3 and the outputs of the Hall elements Ic1, Ic2 and Ic3 to form a signal input in three phases and then logically combined. In a motor circuit composed of a motor driving circuit (5) for outputting an analog switch connected between the stator coil (1) and the motor driving circuit (5) for controlling the current applied to the stator coil ( AS), and connected between the Hall elements (Ic1), (Ic2), (Ic3) and the analog switch (AS) to receive the output signals of the Hall elements (Ic1), (Ic2), (Ic3) to detect the phase The driving circuit of the brushless DC motor comprising a phase detection unit (10) for controlling the analog switch (AS). The phase shift circuit (11) according to claim 1, wherein the phase detector (10) includes a phase shift circuit (11) for shifting the sensed pulses detected by the hall elements (Ic1), (Ic2), and (Ic3) by 60 degrees. Is connected to the output side of the circuit and receives the output of the phase shift circuit 11, the reverse torque generation detection circuit 12 for detecting the time when the reverse torque is generated, and is connected to the output side of the reverse torque generation detection circuit 12 And a switch control circuit (13) configured to control to block the analog switch (AS) when reverse torque is generated in the reverse torque generation detecting circuit (12).