KR100786016B1 - The driving speed control system of direct motor by the change of input voltage and control method thereof - Google Patents

Abstract

A driving speed control system of a DC motor using a change of an input voltage and a control method thereof are provided to form a switching structure by using only a switching transformer. A driving speed control system includes a primary power unit(10) for rectifying AC power, a switching power unit(20) for outputting an induced DC voltage according to a switching signal, and a DC motor(80) operated by a driving voltage according to a control of a control unit(160). A control input unit(90) transmits a request for setting an input voltage of the DC motor as a reference voltage of an idling state to the control unit. A motor power unit(130) generates a driving voltage of the DC motor in a type of playback according to a switching operation of the switching power unit on the basis of the voltage set by the control unit. A 12V power supply unit is connected in a forward type to a rear end of the power supply unit of the motor, and is switched by a switching regulator in order to generate a 12V.

Description

The driving speed control system of a direct current motor by changing the input voltage and its control method {The driving speed control system of direct motor by the change of input voltage and control method}

1 is a block diagram showing a conventional DC motor drive speed control system.

Figure 2 is a block diagram showing a DC motor drive speed control system of the present invention.

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

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

The present invention relates to a DC motor drive speed control system and its control method by changing the input voltage, and to control the drive speed of the DC motor installed in the vehicle to obtain a high efficiency DC motor drive voltage and at the same time direct current A system and method for suppressing noise generated by driving a motor.

In general, an air conditioner such as an air conditioner is provided with a DC motor, the number of revolutions of the DC motor is variable in accordance with a control signal from the outside. As described above, in order for the rotation speed of the DC motor to be changed, the power supply voltage for driving the DC motor must be changed according to the control signal.

1 is a block diagram showing a conventional DC motor drive speed control system. As shown in FIG. 1, the conventional DC motor driving speed control system includes a primary power supply unit 10 for rectifying an AC voltage supplied from the outside to generate a DC voltage, and the primary power supply unit 10. Outputs a DC voltage induced by a DC voltage input from the controller, receives the output DC voltage, and is based on a switching power supply unit 20 configured in a flyback form and an output voltage of the switching power supply unit 20. It includes a 12V power supply unit 30 for switching the input voltage of the switching power supply unit 20 to stably supply the output voltage of 12V.

In addition, the conventional DC motor drive speed control system is supplied with a 12V DC voltage from the 12V power supply unit 30 to switch the output voltage of the 5V power supply unit 40 and the switching power supply unit 20 to generate a constant voltage of 5V By varying the driving voltage switching unit 50 for generating a driving voltage VP for driving the DC motor 80 and the driving voltage VP generated by the driving voltage switching unit 50, the DC motor ( And a control unit 60 for controlling the driving of 80.

In addition, the conventional DC motor drive speed control system, under the control of the control unit 60 is supplied with the drive voltage VP to drive the DC motor unit 70 to drive the DC motor 80, and the direct current A control input unit 90 for inputting a control signal for varying the speed of the motor 80 to the control unit 60, and a display unit 100 for displaying an operation state of the air conditioner according to the control of the control unit 60. It consists of.

The primary power supply unit 10 includes a noise filter 11 for removing noise components of the AC voltage AC, and a rectifier circuit 12 for rectifying the output voltage of the noise filter 11.

The switching power supply unit 20 is a switching transformer in which the primary coil L1 to which the voltage from the primary power supply unit 10 is applied, and the secondary coils L2, L3, L4, and L5 are wound. (21), a switching power supply unit 22 for transmitting power induced in the winding coil L3 of the switching transformer 21 through the diode D2 and the capacitor C2, and from the 12V power supply unit 30. It is composed of a switching circuit unit 23 that is driven according to a switching signal to switch the power from the switching power supply unit 22 to the primary coil L1 of the switching transformer 21.

The 12V power supply unit 30 includes a 12V voltage setting unit 31 for outputting a preset 12V reference voltage, and the winding coil L4 of the switching transformer 21 for the reference voltage from the 12V voltage setting unit 31. And a photocoupler 33 which is driven according to the output section of the comparing section 32 and which applies the switching signal to the switching circuit section 23 of the switching power supply section 20. It consists of.

The driving voltage switching unit 50 includes a motor voltage setting unit 51 for outputting a pulse width modulation (PWM) signal under the control of the control unit 60, and pulses from the motor voltage setting unit 51. A transistor Q1 that is turned on / off by a width modulation signal to switch power induced in the winding coil L5 of the switching transformer 21, and the driving voltage VP output through the transistor Q1. It is composed of a motor voltage detection unit 52 that detects and applies to the control unit 60.

Looking at the operation of the conventional DC motor drive speed control system configured as described above are as follows.

The AC voltage supplied from the outside is rectified after noise filtering by the primary power supply unit 10, and the rectified voltage is smoothed by the capacitor C1 connected to the output terminal of the rectifying circuit 12 to switch power supply. Is applied to the primary coil L1 of the switching transformer 21 of (20).

As described above, when the DC power is applied to the primary coil L1, and the switching circuit unit 23 is being driven, the current by the DC power is transferred through the primary coil L1 and the switching circuit unit 23 to the capacitor (L). It flows to the ground side of C1).

At this time, the secondary coil (L4) is composed of a flyback so that no current flows, while the secondary coil (L5) is composed of the forward (forward), the current flows. At this time, the output voltage, that is, the driving voltage Vp due to the current flowing in accordance with the switching of the transistor Q1 is defined as in Equation 1 below.

VP = Vin * Don

Where Vin is the primary input voltage and Don is the energization time ratio of the primary winding.

On the other hand, when the current does not flow in the primary coil L1 due to the switching circuit unit 23 off, the current flows in the secondary coil L4, and at this time, the diode D3 and the capacitor C3 of the 12V power supply unit 30. The output voltage Vo is defined by Equation 2 below.

Vo = (Vin * (N2 / N1) * (Don / (1-Don))

Where Vin is the primary input voltage, N1 is the primary winding number, N2 is the secondary winding number, and Don is the energization time ratio of the primary winding.

The photocoupler 33 of the 12V power supply unit 30 is turned on / off until the voltage Vo is stabilized at 12V, thereby switching the switching circuit unit 23. At this time, the control unit 60 switches the motor voltage detection unit 52. The driving time of the transistor Q1 is controlled through the motor voltage setting unit 51 while detecting the driving voltage Vp. That is, the motor voltage setting unit 51 maintains the driving voltage Vp at a target value by applying a PWM type switching signal to the base of the transistor Q1 under the control of the controller 60.

The driving voltage Vp is input to the DC motor driver 70 to drive the motor, that is, the DC motor 80 at an appropriate rotational speed.

The conventional DC motor drive speed control system as described above generates a driving voltage as a two-stage switching structure through the switching transformer 21 and the transistor Q1.

However, since the switching structure including the switching transformer 21 and the transistor Q1 is used, there is a problem that the driving voltage is lowered and half the power saving effect to be obtained by employing a DC motor. In addition, the method of suppressing the generation of noise caused by the air flow generated by the high speed operation of the DC motor or the transmission of vibration is not efficient because the switching transformer 21 and the transistor Q1 are used as described above. There is a problem.

The present invention is to solve the above problems, by controlling the drive speed of the DC motor installed in the vehicle to obtain a high efficiency DC motor driving voltage and at the same time noise generated by driving the DC motor by high efficiency drive voltage generation It is an object to provide a system and method for suppressing.

The present invention provides a primary power supply for rectifying an AC voltage, a switching power supply for outputting a DC voltage induced by a DC voltage input from the primary power supply according to a switching signal, and a DC motor driven by a driving voltage under control of a controller. In the drive speed control system of a DC motor comprising a, by detecting the speed of the vehicle determines that the vehicle is in the idle state (idle), requesting the control unit to set the voltage input to the DC motor as the reference voltage of the idle state A control input unit; A motor power supply unit configured to generate a driving voltage of the DC motor in a flyback form according to a switching operation of the switching power supply unit based on the voltage set by the controller; And a 12V power supply unit connected to a rear end of the motor power supply unit in a forward form and switched by a switching regulator to generate a 12V voltage. The drive speed control system of the DC motor by changing the input voltage is provided.

In addition, the present invention includes the step of rectifying the AC voltage, the step of outputting the DC voltage induced by the rectified and input DC voltage according to the switching signal, the step of driving the DC motor by the drive voltage under control A control method of a drive speed control system of a DC motor, comprising: a first step of sensing a speed of a vehicle; If it is determined that the vehicle is in an idle state, a second step of requesting to set a voltage input to the DC motor as a reference voltage in an idle state; Generating a driving voltage of the DC motor according to the switching signal based on the set reference voltage; And a fourth step of generating the 12V DC voltage by switching the generated driving voltage by the switching regulator. The control method of the driving speed control system of the DC motor by changing the input voltage is provided.

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

Figure 2 is a block diagram showing a DC motor drive speed control system of the present invention. As shown in FIG. 2, the DC motor driving speed control system of the present invention includes a primary power supply unit 10 for rectifying an AC voltage supplied from the outside to generate a DC voltage, and the primary power supply unit 10. And a switching power supply unit 20 configured to output a DC voltage induced by the DC voltage inputted from the input, and receive the output DC voltage and combine it in a forward or flyback form.

In addition, the drive speed control system of the DC motor of the present invention, and the motor power supply unit 130 for generating a drive voltage VP 'of the DC motor 80 in the form of a flyback according to the switching operation of the switching power supply unit 20 and A 12V power supply 140 connected to the rear end of the motor power supply unit 130 and switched by the switching regulator 141 to generate a 12V voltage, receives a 12V DC voltage from the 12V power supply 140 and receives a constant voltage of 5V. The reference voltage of the motor power supply unit 130 is set according to the generated 5V power supply unit 150 and the driving voltage VP ′ detected through the motor power supply unit 130 to control the driving of the DC motor 80. And a controller 160.

The switching power source 20 is a winding transformer in which primary coils L1 and secondary coils L2, L3, L4, and L5 to which a voltage from the primary power supply unit 10 is applied are wound. 21 is provided, and the transmission and reception power supply unit 170 for supplying power to the outdoor transmission and reception unit 180 for transmitting and receiving the operation command to the outdoor unit 190 is connected to the secondary coil (L5) of the switching transformer 21 is have.

The motor power supply unit 130 may include a motor voltage setting unit 131 for setting a reference voltage under control of the controller 160, and a driving voltage generated through the secondary coil L4 of the switching transformer 21. VP ') of the motor voltage detection unit 132, the comparison unit 133 for comparing the voltage from the motor voltage detection unit 132 and the motor voltage setting unit 131, and the comparison unit 133 The photocoupler 134 is driven by an output and applies a switching signal to the switching power supply unit 20.

The driving voltage VP ′ induced by the secondary coil L4 of the switching transformer 21 configured in the flyback manner and output through the diode D3 and the capacitor C3 is defined by Equation 3 below.

VP '= (Vin * (N2 / N1) * (Don / (1-Don))

Where Vin is the primary input voltage, N1 is the primary winding number, N2 is the secondary winding, and Don is the ratio of the energization time of the primary winding.

Therefore, in order to change the speed of the motor, that is, the DC motor 80, the controller 160 changes the energization time of the primary coil L1 of the switching transformer 21. In this case, the controller 160 detects the motor voltage. The desired reference voltage is set through the motor voltage setting unit 131 with reference to the driving voltage VP 'detected by 132.

Therefore, when the driving voltage VP 'is not output as much as the desired voltage, the comparator 133 drives the photocoupler 134 to switch the switching circuit unit 23 to change the energization time of the primary coil L1. The desired driving voltage VP 'is obtained.

In addition, a voltage according to Equation 3 is output to the switching power supply unit 22 and the transmission and reception power supply unit 170, which are configured as forwards, and the output voltage maintains a substantially constant voltage unless the current supply time ratio of the switching transformer 21 is extremely small. do. Therefore, even if the driving voltage of the motor power supply unit 130 is changed to change the speed of the DC motor 80, the voltage generated by the secondary coil L3 and the transmission / reception power supply unit 170 of the switching transformer 21 is input voltage. It changes only as much as the change caused by the change.

In addition, the 12V power supply unit 140 is connected to the rear end of the motor power supply unit 130 and acts as a constant load even when the DC motor 80 stops, thereby preventing the intermittent oscillation of the switching transformer 21 due to the light load.

Looking at the operation of the DC motor drive speed control system of the present invention configured as described above are as follows.

First, when AC power is supplied to the primary power supply unit 10, the AC power is rectified by the rectifier 12 to be converted to DC power and applied to the primary coil L1 of the switching transformer 21. At this time, the current of the primary coil L1 is switched by the switching circuit 23 of the switching power supply unit 20.

As described above, when the primary coil L1 is switched, power is transferred to the secondary coil L4 of the switching transformer 21 to drive the 12V power supply unit 140 and the 5V power supply unit 150, and the control unit 160. Will work. At this time, the driving voltage VP ′ maintains the lowest voltage (eg, 15V).

When the control input unit 90 senses the speed of the vehicle and determines that the vehicle is in the idle state, the control input unit 90 requests the control unit 160 to set the voltage input to the DC motor 80 as a reference voltage in the idle state. do. The reference voltage in the idle state is lower than the voltage when the vehicle is in operation.

When the controller 160 is required to drive the rotational speed of the DC motor 80 to a predetermined value through the control input unit 90, the DC motor driving unit 70 is operated to drive the DC motor 80 and the DC motor ( When 80 is normally driven, the motor voltage setting unit 131 is controlled to lower the driving voltage VP 'to a level corresponding to the target rotational speed. At this time, since the result is received through the motor voltage detection unit 132, the control unit 160 performs a stable voltage control while checking the level of the driving voltage VP '.

As described above, the maximum output voltage is constantly maintained at the input voltage and the coil turns ratio in the winding coils L3 and L5 of the switching power supply 22 and the transmission / reception power supply 170 even when the driving voltage VP ′ is varied. do. Therefore, even when the output voltage of the secondary coil L4 fluctuates by about three times, a constant voltage is maintained in the switching power supply 22 and the transmission / reception power supply 170, thereby preventing unnecessary power loss.

In addition, the 12V power supply 140 generates a constant voltage of 12V by the switching operation of the switching regulator 141 even if the input driving voltage VP 'is changed by about 3 times, so that the 12V power supply 140 also serves as a highly efficient and stable power supply device. Will be

3 is a flowchart illustrating a control method of a DC motor drive speed control system according to the present invention. As shown in Figure 3, the control method of the drive speed control system of the DC motor as described above is as follows.

First, the control input unit 90 detects the speed of the vehicle (S100).

Thereafter, the control input unit 90 determines that the vehicle is in an idle state, and requests that the voltage input to the DC motor 80 be set to a reference voltage in an idle state (S200). The reference voltage in the idle state is a lower voltage than when the vehicle is in operation.

Thereafter, the motor power supply unit 130 generates the driving voltage of the DC motor according to the switching signal based on the set reference voltage (S300). This process is the step of setting the reference voltage (S310), the step of detecting the drive voltage generated through the secondary coil of the switching transformer for generating the switching signal (S320). And, the step of comparing the reference voltage and the driving voltage (S330) and is driven by the output of the comparison result, and the step of applying the switching signal (S340).

Thereafter, the 12V power supply 140 switches the generated driving voltage by the switching regulator to generate a 12V DC voltage (S400).

Thereafter, the 5V power supply unit 150 receives the 12V DC voltage to generate a constant voltage of 5V (S500).

Thereafter, the controller 160 sets a reference voltage according to the driving voltage, and controls the driving of the DC motor (S600).

4 is a graph showing the relationship between the speed of the vehicle and the speed of the DC motor of the present invention. As shown in FIG. 4, it is assumed that the speed of the DC 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 DC motor even when the DC motor is driven. However, when the speed of the vehicle is in the idling state, the DC motor rotates at 2800 rpm so that the driver or passenger cannot easily feel the noise of the DC motor.

Although the technical concept of the drive speed control system and method of controlling the DC motor by changing the input voltage as described above has been described with the accompanying drawings, the present invention has been described by way of example only. It is not limited. 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 thereof of the DC motor by changing the input voltage according to the present invention are different from the conventional method in which the drive voltage is generated by a switching structure using a switching transformer and a transistor. It generates an effect that can generate a driving voltage of high efficiency. In addition, the method of suppressing the generation of noise due to the air flow generated by the high speed operation of the DC motor or the transmission of vibration is also more efficient because only the transformer is used.

Claims (6)

A primary power supply for rectifying the AC voltage, a switching power supply for outputting a DC voltage induced by the DC voltage input from the primary power supply according to the switching signal, a DC motor driven by the drive voltage under the control of the control unit In the drive speed control system of a DC motor, A control input unit for sensing the speed of the vehicle and determining that the vehicle is in an idle state, and requesting the control unit to set a voltage input to the DC motor as a reference voltage in the idle state; A motor power supply unit configured to generate a driving voltage of the DC motor in a flyback form according to a switching operation of the switching power supply unit based on the voltage set by the controller; And A 12V power supply unit connected to a rear end of the motor power supply unit in a forward form and switched by a switching regulator to generate a 12V voltage; Drive speed control system of the DC motor by changing the input voltage, characterized in that it comprises a. The method of claim 1, The motor power supply unit, A motor voltage setting unit for setting a reference voltage according to the control of the controller; An electric motor voltage detector for detecting a driving voltage generated through the secondary coil of the switching transformer; A comparison unit for comparing the voltage of the motor voltage detection unit with the motor voltage setting unit; And A photocoupler driven by an output of the comparator to apply a switching signal to the switching power supply; Drive speed control system of the DC motor by changing the input voltage, characterized in that it comprises a. Rectifying an AC voltage, outputting a DC voltage induced by the rectified and input DC voltage in accordance with a switching signal, the drive speed of the DC motor comprising the step of driving the DC motor by the drive voltage under control In the control method of the control system, Detecting a speed of the vehicle; If it is determined that the vehicle is in an idle state, requesting to set a voltage input to the DC motor as a reference voltage in an idle state; Generating a driving voltage of the DC motor according to the switching signal based on the set reference voltage; And A fourth step of generating a 12V DC voltage by switching the generated driving voltage by a switching regulator; Control method of a drive speed control system of a DC motor by changing the input voltage, comprising a. The method of claim 3, The third step, Setting the reference voltage; Detecting a driving voltage generated through a secondary coil of a switching transformer generating the switching signal; Comparing the reference voltage with the driving voltage; And Driven by the output of the comparison result, applying the switching signal; Control method of a drive speed control system of a DC motor by changing the input voltage, comprising a. The method of claim 3, The third step is a control method of a drive speed control system of a DC motor by changing the input voltage, characterized in that for generating a drive voltage of the DC motor in the form of a flyback. The method of claim 3, The fourth step is a control method of a drive speed control system of a DC motor by changing the input voltage, characterized in that for generating a 12V voltage in the forward form.

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