KR20200092902A - Weak field control method using encoder for motor - Google Patents

Abstract

The present invention relates to a weak field control method of a motor using an encoder. More specifically, the present invention relates to a weak field control method of a motor using an encoder which increases instantaneous output by weakly controlling a field of the motor in order to increase torque of the motor. According to the present invention, the weak field control method of a motor using an encoder detects a phase angle using a mechanical encoder plate and an electronic photointerrupter sensor to have a simple circuit configuration and achieve control convenience and low costs. Moreover, the weak field control method of a motor using an encoder detects a current and speed to simply control a weak field of the motor by controlling the phase angle without setting a table for controlling the weak field in advance.

Description

Weak field control method using encoder for motor}

The present invention relates to a method for controlling a field weakening of a motor using an encoder, and more particularly, to a method for controlling a field weakening of a motor using an encoder capable of increasing the instantaneous output by weakly controlling the field of the motor to increase the torque of the motor. It is about.

In general, the motor is composed of a stator (rotor) and a rotor (stator), and when a current is formed by passing a current through the rotor, the rotor rotates by the interaction between the magnetic flux and the rotor magnetic flux. Conversely, these motors have a change in magnetic flux when the rotor rotates, and the amount of time change of the magnetic flux generates an induced electromotive force in the stator coil, and this mechanism is used in the generator.

Therefore, the induced electromotive force generated when the motor rotates is generated in a direction that prevents the rotation of the rotor, and this is called a reverse electromotive force (逆起電力). Since this counter-electromotive force is proportional to the amount of change in the rotation of the rotor, the amount of occurrence is small when the motor rotates at low speed, so it does not significantly affect the motor control. However, when the motor rotates at high speed, the counter-electromotive force also occurs It grows proportionally.

The back EMF generated in this way may cause problems in motor control performed in the electronic control device. That is, when a constant voltage and current are applied, the motor speed or output (torque) corresponding to the voltage and current can be obtained at a low speed, but since the back electromotive force is generated at a high speed, the motor speed or output predicted from the input voltage and current The input voltage and current must be changed to obtain the desired motor speed or output. At this time, current and voltage are applied so that the reverse magnetic flux is generated in a direction opposite to the magnetic flux that generates the back EMF, and this is called field weakening control.

Looking at the principle of conventional weak field control, since the counter electromotive force generated in the motor increases in proportion to the rotational speed of the motor, it measures or calculates the rotational speed of the motor and is opposite to the magnetic flux that generates the counter electromotive force when it is higher than the preset rotational speed Adjust the input current and voltage so that the reverse magnetic flux in the direction to be increased. In this conventional weak field control method, information on the position of the motor is required to know the rotational speed of the motor, and an expensive sensor resolver is required to sense the position of the motor. Problems such as complexity, difficulty in configuring the control circuit, and difficulty in miniaturization due to the motor attachment type occur.

In addition, the process of calculating the rotational speed of the motor using the positional information of the motor is complicated, resulting in a problem that the amount of calculation increases.

As a conventional technique for improving this, a'weak field control device and control method for a driving motor for a motor vehicle steering device using a voltage' has been proposed in Korean Patent Registration No. 10-0804429. This will be described with reference to FIG. 1.

In the related art, first, the sensing unit of the weak field control device senses the input or output voltage of the motor of the automobile steering device and transmits it to the control unit (S21). The control unit determines whether the sensed input or output voltage of the motor is greater than or equal to a predetermined threshold voltage (S22). When it is determined that the input or output voltage of the motor is greater than or equal to the threshold voltage, a command signal capable of generating a reverse magnetic flux is generated and transmitted to the execution unit (S23). The execution unit controls the amount of current applied to the coil of the motor stator to control reverse magnetic flux to be generated (S23).

However, such a conventional technique is a weak field control method that increases the reverse magnetic flux in the direction of attenuating the back EMF when the input or output voltage rises above the threshold voltage by setting the threshold voltage in advance without the need for expensive equipment installation and complicated calculation. However, the voltage threshold is set in advance so that the reverse magnetic flux of the motor is generated only when the input and output voltages are greater than or equal to the threshold.

Republic of Korea Registered Patent No. 10-0804429 Republic of Korea Registered Patent No. 10-0645809 Republic of Korea Registered Patent No. 10-1183065

The present invention is to solve the problems of the prior art as described above, the object of the present invention is to provide a method for controlling a field weakening of a motor using an encoder that can detect a phase angle using a mechanical encoder plate and an electronic photointerrupter sensor. .

In addition, the present invention has an object to provide a method for controlling a weak field of a motor using an encoder capable of simply controlling a weak field of a motor with phase angle control without presetting a table for weak field control by reading current and speed. .

A motor weak field control method using an encoder according to the present invention for achieving the above object comprises the steps of turning on the power of the motor by supplying power to the motor through a power supply and a switching unit for initial driving of the motor; Determining an initial position of an encoder and a sensor installed inside the motor to obtain a rotational speed and phase angle signal of the motor; Outputting a speed control signal for controlling the speed of the motor from the control signal input unit to the ECU; Controlling the switching unit according to the speed control signal received by the ECU to drive the motor; Detecting current and voltage information of the motor and speed information of the motor, outputting the detected information to a weak field signal generating unit, and determining whether to control a weak field based on the information received by the weak field signal generating unit; When the weak field control is executed, the weak field signal generating unit repeats the step of generating a weak field signal for weakening the field of the motor and outputting the weak field signal to the ECU, and when the weak field control is not executed, the control signal Determining whether a command value of the speed control signal output from the input unit is '0'; And if the command value of the speed control signal is not '0', the driving of the motor is continued, and when the command value of the speed control signal is '0', the driving of the motor is stopped. .

The encoder is a mechanical plate, and the sensor is characterized in that it is a photointerrupter sensor comprising a light emitting diode and a phototransistor.

The encoder is characterized in that the square wave, the sensor is set to the sine wave as a reference angle.

The phase angle signal is output by the photointerrupter, and when the weak field signal generator executes the forward weak field control, it receives each of the forward phase control lead signals at the reference angle of the encoder and supplies the signal to the ECU. When executing the weak field control, it is characterized in that each signal of the reverse phase control lead is input from the reference angle of the encoder and the signal is supplied to the ECU.

The signal supplied to the ECU is characterized in that the current, voltage and phase angle.

The field weakening control method of a motor using an encoder according to the present invention can detect a phase angle using a mechanical encoder plate and an electronic photointerrupter sensor, thereby simplifying the circuit configuration and achieving control convenience and low cost.

In addition, the method for controlling the field weakening of a motor using an encoder according to the present invention has an effect of controlling the field weakening of the motor simply by controlling the phase angle without previously setting a table for field weakening control by detecting current and speed. .

1 is a flow chart of a weak field control method according to the prior art.
Figure 2 is a configuration diagram for the weak field control of the motor using the encoder according to the present invention,
3 is an exemplary diagram of an encoder and a sensor in a method for controlling weak field of a motor using an encoder according to the present invention.
Figure 4 is an exemplary view showing the output signal of the sensor in the weak field control method of the motor using the encoder according to the present invention.
5 is a flow chart showing a method for controlling a weak field of a motor using an encoder according to the present invention.

The terms or words used in the present specification and claims should not be interpreted as being limited to ordinary or dictionary meanings, and the inventor can appropriately define the concept of terms in order to explain his or her invention in the best way. Based on the principle that it should be interpreted as meanings and concepts consistent with the technical idea of the present invention.

Therefore, the embodiments shown in the embodiments and drawings described in this specification are only the most preferred embodiments of the present invention, and do not represent all of the technical spirit of the present invention. It should be understood that there may be equivalents and modified examples.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The method for controlling the weak field of a motor using an encoder according to the present invention provides power to the motor 30 through the power supply unit 10 and the switching unit 20 for initial driving of the motor 30, thereby providing the motor 30 ) Turning on the power (S100); Steps to determine the initial position of the encoder 41 and the sensor installed inside the motor 30 to obtain the rotational speed and phase angle signal of the motor 30 (S200); Outputting a speed control signal for controlling the speed of the motor 30 from the control signal input unit 80 to the ECU 70 (S300); Controlling the switching unit 20 according to the speed control signal received by the ECU 70 to drive the motor 30 (S400); It detects the current and voltage information of the motor 30 and the speed information of the motor 30, outputs the detected information to the weak field signal generator 60, and is received by the weak field signal generator 60. Determining whether to control the weak field based on the information; When performing the weak field control, the weak field signal generating unit 60 generates a weak field signal that weakens the field of the motor 30 and outputs the weak field signal to the ECU 70 (S300). Determining whether the command value of the speed control signal output from the control signal input unit 80 is '0' when the weak field control is not executed; Continuing driving of the motor 30 when the command value of the speed control signal is not '0', and stopping driving of the motor 30 when the command value of the speed control signal is '0'; It is provided.

The configuration for implementing the method for controlling the weak field of the motor 30 using the encoder 41 according to the present invention as described above is illustrated in FIG. 2.

Power supply unit 10, switching unit 20, sensor unit, detection unit 50, weak field signal generator 60, ECU for weak field control of motor 30 using encoder 41 according to the present invention (70), a control signal input unit 80 is provided.

The power supply unit 10 supplies power for driving the motor 30, and the switching unit 20 is a speed control waveform of the motor 30 for controlling the motor 30 by receiving power from the power supply unit 10 The switching signal is generated and transmitted to the motor 30. The switching signal output to the switching unit 20 is transmitted to the Interior Permanant Magnet (IPM) motor 30, and the motor 30 is driven by the switching signal. The switching signal output from the switching unit 20 changes in real time according to the control signal output from the ECU 70.

The sensor unit is for controlling the weak field according to the driving of the IPM motor 30, the mechanical plate encoder 41 for obtaining and detecting the rotational speed and phase angle signal of the motor 30, and the photointerrupter sensor 45 Includes.

The encoder 41 is fixed to the shaft of the motor 30 inside the housing of the motor 30 and is rotated together with the motor 30. It is formed as a disc, and the edges are extended in a predetermined length in three different directions, respectively. A piece 42 is formed, and an end portion of each extension piece 42 has a structure in which an interference piece 43 extending and bending backward is formed. The three extension wings are formed in an isometric shape, and are formed in a fan shape.

The photointerrupter sensor 45 is fixedly installed inside the housing of the motor 30. The photointerrupter sensor 45 is disposed at a position spaced apart from the encoder 41 on a side facing the encoder 41, and the PCB 46 formed in a disk shape and a motor when the rotation axis of the motor 30 is rotated Installed in the PCB 46 so as to face each other at a position corresponding to the rotational trajectory of the interference piece 43 so that the interference piece 43 provided at the end of the encoder 41 rotated with the rotation axis of 30 passes through. Light-emitting diodes 47a and phototransistors installed on the first and second support pieces 47 and 48, and the first and second support pieces 47 and 48, respectively, facing each other ( 48a).

The number of revolutions of the motor 30 and the phase angle of the motor 30 may be detected through the encoder 41 and the photointerrupter sensor 45.

The detection unit 50 detects the current and voltage related to the output of the IPM motor 30, and transmits and transmits the detected current and voltage information to the weak field signal generator 60 or the ECU 70.

The weak field signal generating unit 60 receives current and voltage information, phase angle signal, and motor 30 rotation speed information measured by the detection unit 50 and the sensor unit, respectively, and determines whether the weak field is controlled based on the received information. Decide.

The ECU 70 controls the switching unit 20 according to the control signal output and transmitted from the control signal input unit 80, and the control signal input unit 80 receives control signals for controlling the rotational speed of the motor 30. It outputs and transmits to the ECU 70.

The weak field control method of the motor using the encoder according to the present invention having the configuration as described above is the phase angle signal detected by the photointerrupter sensor 45, the current of the IPM motor 30 detected by the detection unit 50, and In order to receive voltage information and to control the torque or speed of the motor 30 in real time according to the received information, the weak field signal generating unit 60 generates a signal that weakens the field of the IPM motor 30, and generates The signal is transmitted to the ECU 70, and the ECU 70 transmits a switching control signal to the switching unit 20, so that the IPM motor 30 can be controlled according to the switching signal output from the switching unit 20 do.

In the present invention, the IPM motor 30 is exemplarily described, but of course, the technical matters of the present invention can be applied to most of the motors 30.

When it is necessary to increase the torque in the control signal input unit 80, the control signal input unit 80 outputs a control signal to the CAN communication unit 71 provided in the ECU 70, and the ECU 70 ) Is to control the switching unit 20 by receiving this control signal.

3 shows an example of the encoder 41 and the photointerrupter sensor 45.

Referring to Figure 3, the encoder 41 is formed to distinguish the On section and the Off section through the interference piece 43 using a mechanical encoder 41, a mechanical encoder coupled to the rotation axis of the motor 30 (41) An electronic sensor having a plate and a photointerrupter sensor 45 can detect the reference angle and phase control lead angle signals S1 and S2 of the encoder 41.

Accordingly, the present invention develops an encoder 41 including a photointerrupter sensor 45, which is a transmissive photo sensor, so that the structure is simple and inexpensive, and the motor can be easily operated without making a table by a resolver adopted in the prior art. 30) position and speed control is possible.

On the other hand, Figure 4 shows an exemplary output signal of the sensor unit according to the present invention.

Referring to FIG. 4, the phase difference between the forward phase control lead angle signal S1 and the reverse phase control lead angle signal S3 of the motor 30 with respect to the reference angle signal S3 detected by the encoder 41 By doing so, the weak field signal generating unit generates a signal for weak field control.

Here, the present invention can also control the position or speed of the motor 30 by controlling the phase using an electronic sensor including the encoder 41 and the photointerrupter sensor 45. Here, the encoder 41 is a square wave, and the photointerrupt sensor 45 is a sine wave S0 as a reference angle signal S2.

5 shows a flow chart for weak field control of the motor 30 according to the present invention.

Referring to Figure 5 will be described in more detail with respect to the weak field control method of the motor 30 using the encoder 41 according to the present invention.

The weak field control method of the motor 30 using the encoder 41 according to the present invention, first, when power is supplied from the power supply unit 10 for initial driving of the motor 30, the initial position of the encoder 41 and the sensor unit , And outputs the speed control waveform of the motor 30 through the switching unit 20 to initially drive the motor 30.

Thereafter, the weak field signal generating unit 60 determines whether the weak field is controlled according to the current and voltage information of the motor 30 detected by the detection unit 50, the speed of the motor 30 detected by the sensor unit, and the capacity of the load. Judge.

The determination of whether or not to control the weak field by the weak field signal generating unit 60 is usually input by the control signal of the control signal input unit 80, and when performing the weak field control, the speed of the motor 30 for controlling the weak field The step (S300) of outputting the control waveform is repeated. The control signal continuously corrected from the control signal input unit 80 is transmitted and transmitted to the ECU 70 while the weak field control is executed, and the ECU 70 controls the switching unit 20 based on the corrected control signal. . At this time, the corrected control signal output from the control signal input unit 80 and input to the ECU 70 is applied to the motor 30 from the switching unit 20 so that the reverse magnetic flux is generated in a direction opposite to the magnetic flux generating the back EMF. Switching signals, ie current and voltage signals.

On the other hand, when the weak field control is not performed, it is determined whether the command value of the speed control signal of the motor 30 transmitted from the control signal input unit 80 is '0' (S500).

Here, when the command value of the motor 30 speed control signal is '0', driving of the motor 30 is stopped, and when the command value is not '0', driving of the motor 30 is continued (S600).

The present invention has been illustrated and described with reference to preferred embodiments, as described above, but is not limited to the above-described embodiments, and to those skilled in the art to which the present invention pertains without departing from the spirit of the present invention. Various changes and modifications will be possible.

10: power supply
20: switching unit
30: motor
41: encoder
45: sensor
50: detection unit
60: weak field signal generator
70: ECU
80: control signal input

Claims (5)

In the method of controlling the field weakening of the motor,
Supplying power to the motor through a power supply and a switching unit for initial driving of the motor to turn on the motor;
Determining an initial position of an encoder and a sensor installed inside the motor to obtain a rotational speed and phase angle signal of the motor;
Outputting a speed control signal for controlling the speed of the motor from the control signal input unit to the ECU;
Controlling the switching unit according to the speed control signal received by the ECU to drive the motor;
Detecting current and voltage information of the motor and speed information of the motor, outputting the detected information to a weak field signal generator, and determining whether to control a weak field based on information received by the weak field signal generator;
When the weak field control is executed, the weak field signal generating unit repeats the step of generating a weak field signal for weakening the field of the motor and outputting the weak field signal to the ECU, and when the weak field control is not executed, the control signal Determining whether a command value of the speed control signal output from the input unit is '0';
And when the command value of the speed control signal is not '0', the driving of the motor is continued, and when the command value of the speed control signal is '0', the driving of the motor is stopped. The weak field control method of the motor using the encoder.
According to claim 1,
The encoder is a mechanical plate,
The sensor is a photo-interrupter sensor comprising a light-emitting diode and a phototransistor. A method for controlling a weak field of a motor using an encoder.
According to claim 1,
The encoder is a square wave, the sensor is a sine wave, the weak field control method of the motor using an encoder, characterized in that set to a reference angle.
According to claim 2,
The phase angle signal is output by the photo interrupter,
The weak field signal generating unit receives a forward phase control lead signal from the encoder's reference angle when supplying the forward weak field control, supplies a signal to the ECU, and executes the reverse field control, the reference angle of the encoder. Method for controlling the weak field of a motor using an encoder, characterized by receiving each signal from the reverse phase control lead and supplying the signal to the ECU.
According to claim 4,
The signal supplied to the ECU is a weak field control method of the motor using an encoder, characterized in that the current, voltage and phase angle.

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