KR20080042566A - The driving speed control system of motor by the change of input voltage and control method thereof - Google Patents

Abstract

A driving speed control system of a motor by a change of input voltage and a control method thereof are provided to suppress noise by accurately reducing driving speed of the motor when a vehicle is in an idle state. A switching unit is installed adjacent to a speed sensor to generate a pulse signal during rotation of a speed cable. A signal input unit(31) receives the pulse signal from the switching unit to output an operation start signal and a speed command signal. An A/D converter(32) receives analog data of the speed command signal from the signal input unit to convert the analog data into digital data. A microcomputer(33) receives the digital data of the speed command signal from the A/D converter to control the entire operation of speed of a motor(36) and outputs a control signal to control a frequency of a PWM(Pulse Width Modulation) signal. A PWM unit(34) receives the control signal from the microcomputer to perform PWM for controlling the speed of the motor. An inverter(35) receives the PWM signal from the PWM unit and converts DC power into AC power of a desired frequency to drive the motor. An encoder(37) detects driving speed of the motor to control the speed of the motor and outputs the detected driving speed of the motor to the A/D converter.

Description

The driving speed control system of motor by PPM control and the control method thereof The motor speed control system of motor by the change of input voltage and control method

1 is a block diagram showing a speed control apparatus of a conventional single phase induction motor.

FIG. 2A is a timing chart of an encoder signal at low speed of the speed control device of the single phase induction motor of FIG. 1 and a drive signal of the single phase induction motor. FIG.

2B is a timing chart of an encoder signal at high speed of the speed control device of the single phase induction motor of FIG. 1 and a drive signal of the single phase induction motor.

Figure 3 is a block diagram showing the configuration of the vehicle speed detecting apparatus of the present invention.

Figure 4 is a schematic diagram showing a vehicle speed detection apparatus of the present invention.

FIG. 5 is an enlarged perspective view of part A of FIG. 4 showing the apparatus for detecting a vehicle speed according to the present invention.

Figure 6 is a block diagram showing a motor drive speed control system of the present invention.

7 is a flowchart illustrating a control method of the motor drive speed control system according to the present invention.

8 is a graph showing the relationship between the speed of the vehicle and the speed of the motor of the present invention.

The present invention relates to a drive speed control system for a motor by PWM control and a control method thereof, and by adjusting the frequency of a pulse width modulation signal, the drive speed of a motor installed in a vehicle can be precisely adjusted and the vehicle is in an idle state. The present invention relates to a control system that suppresses noise by accurately lowering the driving speed of a motor and a control method thereof.

In general, since the conventional motor drive speed control system is determined by the input frequency from the commercial input power source, in the design of the motor, the desired speed is adjusted based on the fundamental frequency of 60 Hz (domestic). have.

1 is a block diagram showing a speed control device of a conventional single phase induction motor, FIG. 2A is a timing chart of an encoder signal at low speed and a drive signal of a single phase induction motor of the speed control device of the single phase induction motor of FIG. 1. 2B is a timing chart of an encoder signal at high speed of the speed control device of the single phase induction motor of FIG. 1 and a drive signal of the single phase induction motor.

 As shown in Fig. 1 and Fig. 2A, the speed control method of the conventional single-phase induction motor is applied to the CPU 3 at every cycle of the encoder 1 signal when the motor 9 whose speed is variable is low. The intervention cutoff signal is input, and the CPU 3 starts the calculation to calculate the drive signal DS for about 0.1 msec by the intervention cutoff signal, and after the operation is finished, the driving signal DS is driven by the drive circuit 5. The rotation of the motor 9 is controlled. When the motor 9 becomes high speed, as shown in Fig. 2B, the operation is started at the time of standing every two cycles of the encoder signal and the operation for 0.1 msec is completed, and then the driving signal DS is driven. Output to (5). In other words, the granularity after completion of one cycle of two cycles of the encoder signal is skipped and the operation is started on the next granularity of one cycle. In this way, since the time for outputting the drive signal DS is shortened, the duty ratio of the on time of the drive signal is increased so that the motor speed is controlled by controlling the rotation even if the motor rotates at a high speed. can do.

By the way, the method of controlling the speed of the motor as described above requires about 0.1 msec time for the operation time of the drive signal of the CPU 3, and interrupts interruption at the rising edge of one cycle of the encoder 1 signal. The signal is input to the CPU 3. Therefore, by this input, the CPU 3 should stop and output the output of the drive signal DS to the drive circuit 5, and after completion of the calculation, the drive signal based on the calculation result is sent to the drive circuit 5. As the motor 9 becomes high speed, the cycle 1 time of the encoder 1 signal is shortened. In this case, the CPU 3 requires the operation time of the predetermined time to generate the drive signal DS. There has been a problem that the output time is shortened and it is difficult to control the rotation speed of the motor 9 at high speed.

In addition, the speed control device of the single-phase induction motor configured as described above configures a servo driver, which is a control device of the motor, in an analog method using an operational amplifier or a variable resistor to change the frequency of the pulse width modulation signal, thereby controlling the speed of the motor. Because of this method, it is necessary to adjust manually by using operational amplifier or variable resistor when adjusting gain or offset, so precisely control the speed of motor due to drift caused by temperature change. There was also a problem that was difficult to do.

In addition, when the above-described motor is installed in a vehicle, even when the vehicle is in an idle state, noise generated by air flow generated by high-speed operation of the motor or noise generated by transmission of vibration can be suppressed accurately. There is no problem.

The present invention is to solve the above problems, by adjusting the frequency of the pulse width modulation signal to accurately adjust the drive speed of the motor installed in the vehicle and at the same time the vehicle is in the idle state (idle) of the motor An object of the present invention is to provide a control system that suppresses noise by accurately lowering the driving speed and a control method thereof.

The present invention includes a speed cable that is rotated according to the running speed of the vehicle, a speedometer connected to the speed cable, and a motor whose drive speed is controlled by the detected driving speed of the vehicle, which is installed in close proximity to the speedometer. A switching unit for generating a pulse signal when the speed cable is rotated; Signal input means for receiving the pulse signal by the switching unit and outputting an operation start signal and a speed command signal; An A / D converter which receives analog data of the speed command signal output from the signal input means and converts the analog data into digital data; controls the overall operation of the motor speed by receiving digital data of the speed command signal converted by the A / D converter. And a microcomputer for outputting a control signal for adjusting the frequency of the pulse width modulated signal; Pulse width modulation means for modulating a pulse width for adjusting a speed of a motor by receiving a control signal output from the microcomputer; An inverter which receives the pulse width modulation signal output from the pulse width modulation means and converts a DC power source into an AC power source having a desired frequency to drive the motor; And an encoder which detects a driving speed of the motor and outputs the A / D converter to adjust the speed of the motor. When the vehicle is in an idle state, the voltage input to the motor drops to a constant voltage. A drive speed control system of a motor by PWM control is provided.

In addition, according to the present invention, the speed cable is rotated according to the traveling speed of the vehicle, the speedoter is connected to the speed cable, and the driving speed of the motor is controlled by the detected driving speed of the vehicle. A first step in which a pulse signal is generated and applied to the signal input means; A second step of the signal input means outputting an operation start signal and a speed command signal for selecting a speed of the motor to an A / D converter; A third step of receiving, by the A / D converter, analog data of the speed command signal output from the signal input means, converting the analog data into digital data and outputting the digital data to a microcomputer; The microcomputer receives digital data of the speed command signal converted by the A / D converter to control the overall operation of the motor speed and outputs a control signal for adjusting the frequency of the pulse width modulation signal to the pulse generator; step; A fifth step in which the pulse width modulating means receives a control signal output from a microcomputer and modulates the pulse width to output the inverter to adjust the speed of the motor; A sixth step in which the inverter receives a pulse width modulation signal for controlling the speed of the motor output from the pulse width modulation means, converts the DC power inputted to the power input terminal into an AC power of a frequency desired by the user to drive the motor; ; And a seventh step of the encoder attached to the motor feeding back the pulse waveform of the driving speed of the motor to the A / D converter. When the vehicle is in an idle state, the voltage input to the motor drops to a constant voltage. A drive speed control method of a motor by PWM control is provided.

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

Figure 3 is a block diagram showing the configuration of the vehicle speed detecting apparatus of the present invention, Figure 4 is a schematic diagram showing a vehicle speed detecting apparatus of the present invention, Figure 5 is a part A of Figure 4 showing the vehicle speed detecting apparatus of the present invention. An enlarged perspective view.

As shown in Fig. 3 to 5, while the engine is operating in order to obtain the engine output, the fuel consumption, the driving performance, the reduction of harmful emissions, etc. according to the running speed of the vehicle, The driving speed of the vehicle is detected by the engine control unit 30 (ECU) for precisely controlling the ignition timing, the supply of the mixer, and the like so that a predetermined function is performed. The drive gear 12 of the transmission 10 rotates at a constant speed according to the driving speed of the vehicle, the speed cable 40 connected to one end of the drive gear 12 and rotated, and the speed cable 40. When the magnet 52 is rotated by the rotational force transmitted and transmitted to the other end of the motor, the torque is generated on the outer rotor 54 so as to control the hair spring 56 so that the instruction 58 indicates a constant speed of the vehicle. In the structure in which the speedometer 50 is configured, a pulse signal is generated by the magnet 52 installed close to the speedometer 50 and rotated when the speed cable 40 is rotated, so that the engine control unit ( One side is connected to the power supply unit to be applied to 30, and the other side is configured with a switching unit 60 made of a reed switch connected to the engine control unit 30.

The switching unit 60 is provided with a first terminal 62 connected to the power supply unit and a second terminal 64 spaced apart from the first terminal 62 at predetermined intervals and connected to the engine control unit 30. ) And a reed switch including a case 66 installed to surround the outer surfaces of the first terminal 62 and the second terminal 64.

On the other hand, reference numeral 70, which is not described in the figure, is a first worm gear that is rotated in conjunction with the rotation of the speed cable 40, 72 is a second worm gear that is interlocked by the first worm gear 70, the second worm gear 72 returns a totalizer indicating the driving distance of the vehicle.

The operation of the vehicle speed detecting apparatus of the present invention as described above is as follows. Assume that a vehicle in which power generated in the engine is shifted to a constant speed range by the transmission 10 is running. When the drive gear 12 mounted on the transmission 10 rotates, and the speed cable 40 connected to the drive gear 12 rotates in conjunction, the speed meter coupled to the speed cable 40 The magnet 52 of 50 rotates. At this time, a torque is generated in the guided rotor 54 on the outside thereof to hold the hair spring 56, and the hair spring 56 tries to stretch and balances the pulling force with the rotor 54. Will stop. As described above, the rotor 54 controls the hair spring 56 and transmits its operation to the guide 58, so that the speed of the vehicle is instructed by the speedometer 50 installed inside the instrument panel (not shown) in front of the driver's seat. It will be.

On the other hand, when the magnet 52 rotated by the speed cable 40 is close to the switching unit 60 (reed switch), the first terminal 62 and the second terminal 64 of the reed switch are short-circuited to generate a pulse signal. Is generated.

As described above, the generated pulse signal is transmitted to the engine control unit 30 and detected at the vehicle speed, and the engine control unit 30 improves the engine output, the fuel consumption, and the driving performance according to the traveling speed of the vehicle. It is used as a signal to precisely control the engine idling speed, ignition timing, and the supply of the mixer in order to obtain improvement and reduction of harmful emissions.

Figure 6 is a block diagram showing a motor drive speed control system of the present invention. As shown in FIG. 6, the motor drive speed control system of the present invention includes a signal input means 31, an A / D converter 32, a microcomputer 33, a pulse generating means 34, an inverter 35, A motor 36 and an encoder 37 are included, belonging to the engine control unit 30 of FIG.

The signal input means 31 outputs an operation start signal and a speed command signal for selecting the speed of the motor. The signal input means 31 generates a pulse signal while the first terminal 62 and the second terminal 64 of the reed switch of the switching unit 60 of FIG. 5 are short-circuited and input to the signal input terminal 31. do.

The A / D converter 32 receives analog data of the speed command signal output from the signal input means 31 and converts the analog data into digital data.

The microcomputer 33 receives digital data of the converter speed command signal from the A / D converter 300 to control the overall operation of the motor speed and to control the frequency of the pulse width modulation (PWM) signal. Output The microcomputer 33 receives digital data of the speed command signal converted by the A / D converter 32, and performs a central processing unit (CPU) 33c for performing a speed operation and a current operation, and the central processing unit ( RAM (RAM) 33a for temporarily storing data calculated by the CPU, 33c, and ROM (ROM, 33b) for storing digital data output at regular intervals using a timer (Timer, 33d).

The pulse width modulating means 34 receives a control signal output from the microcomputer 33 and modulates a pulse width for adjusting the speed of the motor 36.

The inverter 35 receives a pulse width modulation signal for adjusting the speed of the motor 36 output from the pulse width modulation means 34, converts the DC power input to the input terminal into an AC power of a desired frequency, The motor 36 is driven.

The encoder 37 is attached to the motor 36 and detects the driving speed of the motor 36 and outputs it to the A / D converter 32 to adjust the speed of the motor 36.

7 is a flowchart illustrating a control method of the motor drive speed control system according to the present invention. As shown in Figure 7, the control method of the motor drive speed control system of the present invention is as follows.

First, a pulse signal is generated when the speed cable is rotated and applied to the signal input means (S10).

Thereafter, the signal input means outputs an operation start signal and a speed command signal for selecting the speed of the motor to the A / D converter (S20).

Thereafter, the A / D converter receives analog data of the speed command signal output from the signal input unit, converts the analog data into digital data, and outputs the digital data to the microcomputer (S30).

Then, the microcomputer receives the digital data of the speed command signal converted by the A / D converter, and outputs a control signal for controlling the frequency of the pulse width modulation signal to the pulse generating means while controlling the overall operation of the motor speed. (S40). The output control signal is calculated by receiving digital data of the speed command signal converted by the A / D converter from a central processing unit of a microcomputer.

Thereafter, the pulse width modulation means receives the control signal output from the microcomputer and modulates the pulse width in order to adjust the speed of the motor (S50).

Thereafter, the inverter receives a pulse width modulation signal for controlling the speed of the motor output from the pulse width modulation means, converts the DC power input to the power input terminal into an AC power of the frequency desired by the user to drive the motor Adjust the speed of (S60).

Subsequently, the encoder attached to the motor feeds back the pulse waveform of the driving speed of the motor to the A / D converter, so that the speed of the motor can be easily adjusted (S70).

8 is a graph showing the relationship between the speed of the vehicle and the speed of the motor of the present invention. As shown in FIG. 8, it is assumed that the speed of the motor when the vehicle is running at 15 km / s is 3200 rpm. When the vehicle is in operation, it is difficult for the driver or passenger to feel the noise of the motor even when the motor is driven. However, when the speed of the vehicle is in the idling state, the motor rotates at 2800 rpm so that the driver or passenger cannot easily feel the noise of the motor.

Although the technical idea of the drive speed control system and the control method of the motor by the PWM control as described above has been described with the accompanying drawings, this is to illustrate the best embodiment of the present invention by way of example to limit the present invention It is not. In addition, it will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit of the present invention.

The drive speed control system and control method of the motor by PWM control according to the present invention can simplify the configuration of the motor because the motor installed in the vehicle is configured as a digital servo driver to adjust the frequency of the pulse width modulation signal. In addition, the speed of the motor can be precisely adjusted by eliminating the drift caused by the temperature. In addition, when the vehicle is in an idle state, noise can be suppressed by accurately lowering the driving speed of the motor.

Claims (4)

A speed cable rotated according to the driving speed of the vehicle, a speedometer connected to the speed cable, and a motor whose driving speed is controlled by the detected driving speed of the vehicle, A switching unit installed close to the speedometer and generating a pulse signal when the speed cable is rotated; Signal input means for receiving the pulse signal by the switching unit and outputting an operation start signal and a speed command signal; An A / D converter which receives analog data of the speed command signal output from the signal input means and converts the analog data into digital data; A microcomputer that receives digital data of the speed command signal converted by the A / D converter and controls the overall operation of the motor speed and outputs a control signal for adjusting the frequency of the pulse width modulation signal; Pulse width modulation means for modulating a pulse width for adjusting a speed of a motor by receiving a control signal output from the microcomputer; An inverter which receives the pulse width modulation signal output from the pulse width modulation means and converts a DC power source into an AC power source having a desired frequency to drive the motor; And An encoder which detects a driving speed of the motor and outputs the same to the A / D converter to adjust a speed of the motor; The drive speed control system of the motor by the PWM control, characterized in that when the vehicle is in the idle state (idle), the voltage input to the motor drops to a constant voltage. The method according to claim 1, The microcomputer, A central processing unit which receives digital data of the speed command signal converted by the A / D converter and performs speed operation and current operation; And A RAM for temporarily storing data calculated by the central processing unit, and a ROM for storing digital data output at predetermined time intervals using a timer; Drive speed control system of the motor by the PWM control, comprising a. The speed cable is rotated according to the driving speed of the vehicle, the speedoter is connected to the speed cable, and the driving speed of the motor is controlled by the detected driving speed of the vehicle, A first step in which a pulse signal is generated upon rotation of the speed cable and applied to a signal input means; A second step of the signal input means outputting an operation start signal and a speed command signal for selecting a speed of the motor to an A / D converter; A third step of receiving, by the A / D converter, analog data of the speed command signal output from the signal input means, converting the analog data into digital data and outputting the digital data to a microcomputer; A fourth step in which the microcomputer receives the digital data of the speed command signal converted by the A / D converter and controls the overall operation of the motor speed and outputs a control signal for adjusting the frequency of the pulse width modulation signal to the pulse generator; ; A fifth step in which the pulse width modulating means receives a control signal output from a microcomputer and modulates the pulse width to output the inverter to adjust the speed of the motor; A sixth step in which the inverter receives a pulse width modulation signal for controlling the speed of the motor output from the pulse width modulation means, converts the DC power input to the power input terminal into an AC power of a frequency desired by the user to drive the motor; ; And An encoder attached to the motor feeds back a pulse waveform of a driving speed of the motor to the A / D converter; The drive speed control method of the motor by the PWM control, characterized in that when the vehicle is in the idle state, the voltage input to the motor drops to a constant voltage. The method according to claim 3, The fourth step, Receiving the digital data of the converted speed command signal by the A / D converter and performing speed operation and current operation; Storing RAM, which temporarily stores the data calculated by the central processing unit, and digital data that is output at regular intervals using a timer; Driving speed control method of the motor by the PWM control, comprising a.

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