KR100408063B1 - Braking method of washing machine using sensorless bldc motor - Google Patents

Abstract

The present invention relates to a braking method of a washing machine employing a sensorless BCD motor, and to control the current generated by the torque and the flux according to the magnitude of the DC link voltage to brake the washing machine. To this end, the present invention provides a washing machine employing a sensorless BCD motor, comprising: a first process of measuring a DC voltage across a capacitor when a braking signal for braking the washing machine is input by a user; A second process of comparing the magnitudes of the DC voltage measured in the first process with a reference DC voltage; As a result of the comparison of the second process, if the measured DC link voltage is greater than the reference DC voltage, the torque current is controlled to be a relatively small '-' or '+' value, and the flux current is controlled to be a relatively small '-' value. A third process of controlling the controller to brake the washing machine; As a result of the comparison of the second process, if the measured DC link voltage is smaller than the reference DC voltage, the torque current is controlled to be a relatively large '-' value, and the flux current is controlled to a relatively large '-' value. It consists of a fourth process of braking the.

Description

Braking method of washing machine which adopted sensorless BCD motor {BRAKING METHOD OF WASHING MACHINE USING SENSORLESS BLDC MOTOR}

The present invention relates to a braking method of a washing machine employing a sensorless BCD motor, and in particular, employs a sensorless BLC motor which controls the current generated by torque and flux according to the magnitude of the DC link voltage to brake the washing machine. A braking method of a washing machine.

In general, in order to perform sensorless control in a washing machine using a BCD motor, the current of the DC link is detected to extract phase current information of the motor, and the phase voltage of the motor is separately detected and operated.

If the washing machine is to be decelerated, the phase resistance of the motor is used to stop the large inertia load, which causes the output of the inverter to be cut off and thus does not perform the continuous sensorless operation. It demonstrates in detail with reference.

FIG. 1 is a block diagram showing a drive inverter of a general three-phase AC motor, wherein the smoothing capacitors C1 and C2 for smoothing the rectified commercial AC power supply and the smoothing capacitors C1 and C2 are shown in FIG. An inverter unit for varying a DC voltage into a three-phase AC voltage by a control signal of a microcomputer, and a motor driven by the three-phase AC voltage of the inverter unit; The microcomputer detects the rotor position of the motor and controls the driving of the inverter according to the sensor connected directly to the rotor shaft of the motor.

FIG. 2 is a block diagram showing a configuration of a sensorless control device of a general BCD motor. As shown in FIG. 2, a comparator 1 comparing a current motor speed signal with a desired motor speed and outputting a comparison signal according thereto is shown. Wow; A speed controller (2) for outputting a speed control signal in accordance with the comparison signal of the comparator (1); A voltage command generator (3) which receives the speed control signal and the motor rotor position signal of the speed controller (2) and generates a voltage command accordingly; An inverter unit (4) for varying the DC link voltage to a three-phase AC voltage by the voltage command of the voltage command generator (3); A current / voltage detector 6 for detecting a voltage of each phase at an output terminal of the inverter unit 4 and detecting the DC link voltage Vdc through a DC link resistor Rdc; The current / voltage detection signal output from the current / voltage detector 6 is input to the speed / position calculation unit 7 for outputting the motor rotor position signal according to a predetermined operation and outputting the current motor speed signal. The operation of such a conventional apparatus will be described.

First, the comparator 1 compares a current motor speed signal with a desired motor speed, and outputs a comparison signal according to the speed control, and the speed controller 2 receives a comparison signal of the comparator 1 according to the speed control signal. That is, if the current motor speed is smaller than the desired motor speed, the speed control signal increases the motor speed. If the current motor speed is larger than the desired motor speed, the speed control signal decreases the motor speed. do.

Subsequently, the voltage command generator 3 receives the speed control signal of the speed controller 2 and the motor rotor position signal of the speed / position calculation unit 7 to be described later, and receives the voltage command according to each of the inverter units 4. The inverter unit 4 converts the DC link voltage Vdc into a three-phase AC voltage according to the voltage command.

Then, the motor 5 is driven by the three-phase AC voltage generated by the inverter unit 4.

On the other hand, the current / voltage detector 6 detects the voltage of each phase at the output terminal of the inverter unit 4 and detects the DC link current through the DC link resistance, that is, in series with the DC link terminal as shown in FIG. DC link current is detected through the resistor connected to

In this case, the speed / position calculation unit 7 receives a voltage and a current from the current / voltage detector 6 and calculates the predetermined voltage and current to calculate the motor rotor position signal and the current motor speed according to the voltage command generator 3. Output to comparator 1.

Here, the speed / position calculation unit 7 calculates the speed or position of the motor using the following equation.

here, :resistance Motor Rotor Position

:inductance Motor speed

: Phase voltage Phase current

Back EMF Constant

Thereafter, the above-described operation is repeatedly performed to control the driving of the motor 5.

At this time, in the case of the washing machine employing the BCD motor as described above, in the braking mode, if the measured DC link voltage is greater than the reference DC voltage as shown in FIG. 4, the speed decrease slope is reduced, and the measured DC link voltage is smaller than the reference DC voltage If it is, the speed decrease slope is increased, then the current command value by speed control is calculated and the moto is driven accordingly.

That is, in the case of a washing machine employing a BCD motor, the washing machine is braked by detecting the magnitude of the DC link voltage and controlling the voltage and the phase angle of the voltage. In this case, the braking time is long because the phase angle of the current cannot be directly controlled. There is a problem losing.

On the other hand, when a general-purpose inverter is employed, the deceleration slope is controlled according to the magnitude of the DC link voltage, that is, the speed gradient is detected and the speed is calculated, and then the braking is controlled by the current output through the speed controller. There is a problem that occurs.

The present invention has been made to solve the above problems, the braking method of a washing machine employing a sensorless BCD motor to control the current generated by the torque and flux according to the magnitude of the DC link voltage to brake the washing machine. The purpose is to provide.

1 is a schematic view showing a driving circuit of a general BCD motor.

Figure 2 is a block diagram showing the configuration for a sensorless control device of a general BCD motor.

3 is a circuit diagram showing a state of detecting a phase current using a DC link resistance in FIG.

Figure 4 is an operation flow diagram of a braking method of a washing machine employing a conventional sensorless BCD motor.

Figure 5 is an operation flow diagram for a braking method of a washing machine employing the sensorless BCD motor of the present invention.

Fig. 6 is a waveform diagram showing control of a DC voltage, a torque current, and a flux current across the capacitor according to the present invention.

** Explanation of symbols for main parts of drawings **

1: comparator 2: speed controller

3: voltage command generator 4: inverter section

5: motor 6: current / voltage detector

7: Speed / position calculator

The present invention for achieving the above object, in the washing machine employing a sensorless BCD motor, the first process of measuring the DC voltage across the capacitor when the braking signal for braking the washing machine by the user is input; ; A second process of comparing the magnitudes of the DC voltage measured in the first process with a reference DC voltage; As a result of the comparison of the second process, if the measured DC link voltage is greater than the reference DC voltage, the torque current is controlled to be a relatively small '-' or '+' value, and the flux current is controlled to be a relatively small '-' value. A third process of controlling the controller to brake the washing machine; As a result of the comparison of the second process, if the measured DC link voltage is smaller than the reference DC voltage, the torque current is controlled to be a relatively large '-' value, and the flux current is controlled to a relatively large '-' value. Characterized in that the fourth process of braking.

Hereinafter, with reference to the accompanying drawings, the operation and effects of the braking method of the washing machine employing the sensorless BCD motor according to the present invention will be described in detail.

Apparatus to which the braking method of the washing machine employing the sensorless BCD motor of the present invention is applied is the same as in FIG. 1, and FIG. 5 is an operation flow diagram of the braking method of the washing machine employing the sensorless BLC motor of the present invention. A first step of measuring a DC voltage across the capacitor when a braking signal for braking the washing machine is input by a user as shown in the figure; Comprising a second step of comparing the magnitude of the DC voltage and the reference DC voltage measured in the first step to control the flux current and the torque current to brake the washing machine.

The second process may include a first step of controlling the magnitude of the torque current to be a relatively small '-' or '+' value when the measured DC link voltage is greater than the reference DC voltage; When the measured DC link voltage is smaller than the reference DC voltage, the second step of controlling the magnitude of the torque current to be a relatively large '-' value is described. The operation of the present invention configured as described above will be described.

First, in the normal mode, the voltage command by the speed control is generated to control the torque current and the flux current to control the driving of the BMD motor.

That is, the comparator 1 compares the motor speed desired by the user with the current motor speed signal and outputs a comparison signal according thereto, and the speed controller 2 receives the comparison signal of the comparator 1 and thus the speed control signal accordingly. That is, if the current motor speed is smaller than the desired motor speed, the speed control signal increases the motor speed. If the current motor speed is larger than the desired motor speed, the speed control signal decreases the motor speed. do.

Subsequently, the voltage command generator 3 receives the speed control signal of the speed controller 2 and the motor rotor position signal of the speed / position calculation unit 7 to be described later, and receives the voltage command according to each of the inverter units 4. Applied to the switching element, and accordingly, the inverter unit 4 converts the DC link voltage Vdc into a three-phase AC voltage according to the voltage command and outputs it, that is, controls the flux current and the torque current by the voltage command. To control the driving of the motor.

6 is a waveform diagram showing the relationship between the DC link voltage, the flux current, and the torque current.

Then, the motor 5 is driven by the three-phase AC voltage generated by the inverter unit 4.

On the other hand, the current / voltage detector 6 detects the voltage of each phase at the output terminal of the inverter unit 4 and detects the DC link current through the DC link resistance.

In this case, the speed / position calculation unit 7 receives a voltage and a current from the current / voltage detector 6 and calculates the predetermined voltage and current to calculate the motor rotor position signal and the current motor speed according to the voltage command generator 3. Output to comparator 1.

When operating as described above and switching to the braking mode, the current / voltage detector 6 detects the DC link voltage and applies it to the speed / position calculation unit 7, and the speed / position calculation unit 7 performs the current / voltage. The DC voltage measured by the voltage detector 6 is compared with a predetermined reference DC voltage and a signal is applied to the voltage command generator 3 to control the flux current and the torque current according to the comparison result.

Accordingly, the voltage command generator 3 applies the voltage command value corresponding to the signal output from the speed / position calculation unit 7 to the inverter unit 4 to brake the motor. Since the link stage voltage is variable, the flux current and the torque current are also variable, thereby improving the responsiveness to the voltage.

The torque current is a current that generates the power of the motor, and when the torque current is '+', the torque rotates the load, and when the torque current is '-', the torque stops the load while returning the energy stored in the load to the power source. do.

The flux current is a current in which the reverse electromotive force and the phase of the motor are perpendicular to each other, thereby consuming energy in the resistance of the motor.

Herein, the present invention will be described in detail with reference to FIG.

First, when a braking signal for braking the washing machine is input by the user, the DC voltage across the capacitor is measured.

Then, the magnitude of the measured DC voltage and the reference DC voltage is compared, and the flux current and the torque current are controlled according to the comparison result to brake the washing machine.

If the measured DC link voltage is greater than the reference DC voltage, the torque current is controlled to be a relatively small '-' value (Iq1) or '+' value, and at the same time the flux current is controlled to have a relatively small '-' value (Id1). ) So that energy is continuously consumed through the motor.

On the other hand, if the measured DC link voltage is smaller than the reference DC voltage, the torque current is controlled to have a relatively large '-' value (Iq2), and the flux current is controlled to have a relatively large '-' value (Id2). Energy is continually consumed through the motor.

In other words, the present invention measures the DC voltage across the capacitor when braking the motor, and compares the DC voltage with a preset DC voltage. When the measured DC link voltage is larger than the preset DC voltage, the magnitude of the torque current is relatively small. If the measured DC link voltage is smaller than the preset DC voltage, the torque current is controlled to be a relatively large '-' value to improve the responsiveness to the voltage.

As described in detail above, the present invention has the effect of stably braking the washing machine by directly controlling the current generated by the torque and the flux according to the magnitude of the DC link voltage.

Claims (4)

In the washing machine which adopted sensorless BCD motor, A first step of measuring a DC voltage across the capacitor when a braking signal for braking the washing machine is input by the user; A second process of comparing the magnitudes of the DC voltage measured in the first process with a reference DC voltage; As a result of the comparison of the second process, if the measured DC link voltage is greater than the reference DC voltage, the torque current is controlled to be a relatively small '-' or '+' value, and the flux current is controlled to be a relatively small '-' value. A third process of controlling the controller to brake the washing machine; As a result of the comparison of the second process, if the measured DC link voltage is smaller than the reference DC voltage, the torque current is controlled to be a relatively large '-' value, and the flux current is controlled to a relatively large '-' value. Braking method of a washing machine employing a sensorless BCD motor, characterized in that performed in a fourth process of braking. delete delete delete