KR100250108B1 - Conduction angle control apparatus of an interior permanent magnet bldc motor - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a permanent magnet embedded (IPM) BLDC motor, which is configured to control an elevation angle when driving a stator phase by using reluctance when driving a two-phase conduction method. The present invention relates to an apparatus for controlling the conduction angle of a buried type BDC motor for increasing the total torque by extending the conduction section on each stator.

In the related art, since the motor is controlled by setting the constant angle constant, the section of the current flowing in the drive signal output section is shortened, so that the magnetic torque cannot be used at the maximum, resulting in high efficiency in driving the motor. Will fall.

In the present invention, in order to solve the problems described above, by varying the conduction angle to lengthen the conduction section of the BLDC motor to maximize the magnitude of the torque generated by using the maximum magnetic torque and magnetoresistive torque. By doing so, it is possible to improve the efficiency of the motor.

Description

Conduction angle control device of embedded DC motor

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a permanent magnet embedded (IPM) BLDC motor, which uses a magnetic resistance when driving a two-phase conduction method to control an advancing angle during driving of each stator phase. The present invention relates to an apparatus for controlling the conduction angle of a buried type BDC motor for increasing the total torque by extending the conduction section on each stator.

First, as shown in FIG. 1, the control device of the BLDC motor is configured to smooth the voltage rectified by the bridge diode BD1 and the bridge diode BD1. Smoothing capacitor C1, an inverter unit 1 for converting the smoothed DC voltage from a BLDC to a desired variable voltage and variable frequency AC, an inverter control unit 2 for controlling the inverter unit 1, and an inverter It consists of a BLDC motor (3) driven by the voltage applied from (1),

The inverter controller 2 uses the voltage output from the inverter 1 and supplied to the phases A, B, and C of the stator and the reference potential point voltage VN of the BLDC motor 3. The power supply means of the inverter unit 1 is controlled by a position detecting unit 4 for detecting a position relative to the stator of the rotor, and information transmitted from the position detecting unit 4 and a control signal about the rotation direction. A commutation signal generator 5 for generating a reference signal for switching on / off and information output from the position sensing unit 4 are processed to sense the speed of the BLDC motor 3 and By using the speed control unit 6 to control the speed of the motor compared to the predetermined target speed programmed, the voltage control signal output from the speed control unit 6 and the drive signal output from the drive signal generator 5. PWM processing to handle plus width modulation (PWM) (7) and a gate driver (8) for driving the inverter unit 1 by implementing an interface with the inverter unit 1 by receiving a PWM-processed driving signal from the PWM processor 7. It is composed of

Reference numeral 9 denotes a power supply unit for inverter control.

The BLDC motor controller configured as described above receives commercial AC power and rectifies through the bridge diode BD1, and applies the DC voltage smoothed by the smoothing capacitor C1 to the inverter unit 1 to supply the inverter unit 1. Will be driven.

The inverter unit 1 driven as described above is operated by the BLDC motor 3 to supply AC of a desired voltage and frequency under the control of the inverter controller 2 to operate the BLDC motor 3.

2 shows an equivalent circuit and an inverter unit 1 of the BLDC motor 3, wherein the inverter unit 2 includes a plurality of power switching elements Q1 to Q6 and the switching element Q1. And free-wheeling diodes D1 to D6 connected in reverse parallel to ˜Q6).

In the inverter section 2 configured in this manner, as driven by the gate driver 8, each of the switching element transistors Q1 to Q3 connected to the high potential portion and the transistors Q4 to Q6 connected to the low potential are each one. In pair, it supplies constant AC voltage to each phase (A, B, C) of stator.

On the other hand, when a constant AC voltage is applied to each phase (A, B, C) of the stator constituting the BLDC motor 3 in this way, current flows in the coil wound around each phase (A, B, C) of the stator. In addition, the magnetic field formed by the current generates a rotating magnetic field spatially rotating in the air gap between the motor and the rotor so that the rotor rotates in synchronization.

As described above, when the rotor is rotated, the position detecting unit 4 detects the position of the rotor and outputs the position to the driving signal generating unit 5 and the speed control unit 6. ), The control voltages VA, VB, VC supplied from the inverter 2 to the BLDC motor 3, and the reference potential voltage VN of the BLDC motor 3, respectively. Detect the position of the rotor with respect to C).

In this way, the speed controller 6 determines the rotational speed of the motor by using the information on the position of the rotor transmitted from the position sensor 4.

Thereafter, the determined rotation speed is compared with a predetermined target target speed, and when a comparison result error occurs, a control signal, that is, a BLDC motor 3, for allowing the BLDC motor 3 to rotate at the target speed. Information on the direction of rotation of the motor and the voltage applied to the BLDC motor 3 is output.

At this time, the drive signal generator 5 turns on / off each of the transistors Q1 to Q6 of the inverter 1 by using the information on the rotational direction of the BLDC motor 3 and the position of the rotor. A constant driving signal (commutation signal) for switching operation is generated and output to the PWM processor 7.

The PWM processor 7 pulse width modulates a predetermined driving signal input from the PWM processor 7 according to the information on the voltage applied to the BLDC motor 3 applied from the speed controller 6. Output to 8).

The gate driver 8 supplies the pulse width modulated drive signal to each of the transistors Q1 to Q6 of the inverter 2, so that each of the transistors Q1 to Q6 is turned on and off to operate the BLDC motor 3. AC voltage is supplied to each phase (A, B, C) of the stator constituting the rotation of the BLDC motor (3).

(A) (b) of FIG. 3 shows the rotor structure and the generated torque of the Surface Permanent Magnet (SPM) BLDC motor, and (c) (d) is the circuit of the IPM BLDC motor. This diagram shows the electronic structure and the generated torque.The SPM generates the maximum magnetic torque at an electrical angle of 90 degrees from the reference point, but in the case of the IPM, the magnetoresistance torque is reduced by the difference in the magnetoresistance between the d and q axes. Torque) is generated, so as in (d), the angle for maximizing the magnetic torque and the magnetoresistive torque is electrically greater than 90 degrees from the reference point.

As described above, the magnitude of the Advance Angle is determined by the operating state of the load, that is, the magnitude of the current flowing through the stator and the speed of the rotor. (D-axis is the direction of the rotor magnetic field by the permanent magnet, q The axis is the direction that is electrically perpendicular to the direction of the d axis.)

In this way, the torque of the motor is controlled according to the relative difference between the direction (d-axis) of the magnetic field and the electrical direction perpendicular to the direction (q-axis), whereby the position detection of the rotor is performed by using an open phase of the stator angle. The driving section of each phase is determined from the induced voltage of the non-conducting state.

In the case of surface-mounted BLDC motor, the driving section of each phase is defined as the section in which the induced voltage of each phase is flat (typically 120 degrees), as shown in Fig. 4B. To change, the duty of PWM is determined according to the load.

However, in the case of the embedded BLDC motor, as shown in (c) of FIG. 4, in order to perform the maximum torque operation, the angle of the drive section is moved forward by α as compared with the case of the surface mount type.

The magnitude of the shifted angle is called an advance angle.

As described above, this is to obtain the maximum torque by using the magnetic torque generated by the magnetic field of the permanent magnet and the stator winding and the magnetoresistive torque generated by the magnetoresistance varying according to the position of the rotor.

In general, the conduction angle of each phase of the stator is set to 120 ° in order to balance phase current and phase voltage in the three phases.

In this way, when the fastening angle is set and driving of each phase is performed by the set fastening angle, the A-phase torque caused by the A-phase current has a waveform as shown in FIG. 5C.

That is, in the case of driving in this way, the section of the current flowing in the section in which the counter electromotive force (EMF) is flattened is shortened, so that the magnetic torque cannot be used at the maximum.

Since the section of the current flowing in the flat section is shortened, the magnetic torque cannot be used at the maximum, and the efficiency of driving the motor is reduced.

In the present invention, in order to solve the above problems, it is possible to maximize the magnitude of the generated torque by lengthening the conduction section of the BLDC motor, thereby improving the efficiency of the motor.

1 is a block diagram of a sensorless control device of a conventional conventional BLDC motor.

2 is a circuit diagram showing an equivalent circuit and an inverter of a general BLDC motor.

3A is a diagram showing the rotor structure and the waveform of the magnetic torque of the surface-mounted BLDC motor, and (C) is the waveform of the rotor structure and the generated torque of the buried BLDC motor. Shown.

4 is a view showing a drive signal waveform of a conventional embedded BLDC motor, (a) is a back EMF waveform diagram of phase A, (b) is a drive signal waveform diagram according to the back electromotive force. (C) is waveform diagram of driving signal which moves conduction section by setting up fast angle.

In the prior art of Fig. 5, (a) to (d) are a phase waveform current waveform and a phase torque waveform diagram according to a drive signal.

6A to 6D are diagrams illustrating current waveforms of phase A and waveforms of phase A according to a drive signal according to the present invention.

FIG. 7 is a diagram showing current waveforms and torque waveforms of phase A according to a driving signal according to another embodiment of the present invention.

Looking at the configuration of the conduction angle control device of the buried BCD motor of the present invention, the inverter control device, the position sensing means for detecting the position of the rotor, the position information of the rotor detected from the position sensing means and Drive signal generating means for generating a reference signal so that the power switching element of the inverter unit can be turned on / off by the direction control signal, and the advance angle of the drive signal according to the magnitude of the load (magnitude of phase current) to use the magnetoresistive torque. (Advance Angle) and the conduction angle (Conduction Angle) variable the conduction angle variable means, by processing the position information of the rotor transmitted from the position sensing means to sense the speed, and compared with the pre-programmed target speed motor Speed control means for controlling the speed of the signal, pulse width modulation means for pulse width modulation processing of the drive signal output from the drive signal generation means, and pulse width; It is made as a component of the inverter driving means for driving the inverter as a pulse width modulated drive signal from the adjusting means. It is characterized by driving each phase by controlling the conduction section by angle.

The conduction angle control device of the buried type BDC motor of the present invention having such a configuration determines and applies a conduction angle suitable for load conditions when driving the stator phase so that the conduction section of each stator phase is larger than 120 degrees as an electric angle. It is to increase the total torque by overlapping the current between the phases, when the motor rotates, the position sensing means detects the position of the rotor, the drive signal generated according to the detected position of the rotor The means generates a drive signal.

At the same time, the speed control means recognizes the position of the rotor detected by the position sensing means, detects the rotation speed of the motor, and outputs a voltage control signal for controlling the rotation speed of the motor.

The voltage control signal and the driving signal output in this way are pulse-width modulated by the pulse lock modulating means and transferred to the inverter driving means to drive the inverter.

In this case, in the conduction angle variable means, the load is converted from the calculated rotational speed by determining the position of the rotor using the point of zero-crossing from the speed control means. The conduction angle is varied by recognizing the difference between the current component in the q-axis and the current component in the d-axis according to the load. Accordingly, the conduction angle is varied. FIG. 6 shows the driving signal, the current waveform, As shown in FIG. 6, the conduction angle varying means adds the forward angle α to increase the conduction section in the section where the A-phase back EMF is flat, as shown in FIG. 6.

As the conduction section becomes longer in this manner, the amount of current flowing increases, enabling maximum use of the magnetoresistive torque, and conduction between stator phases (A and B phases, B and C phases, C and A phases). By overlapping, the magnetic torque can be used to the maximum.

As described above, the conduction angle variable means adds a conduction angle to the drive signal output from the drive signal generating means to form a long conduction section. The time using the RC time constants of the resistor R and the capacitor C The conduction section can be lengthened by the delay, or the conduction section can be lengthened by combining a device having a latch function such as flip-flop or a method of lengthening the conduction section using a timer. It can be implemented in hardware such as a method.

On the other hand, as another embodiment of the present invention, it is also applicable to the case of reducing the overlapping section of the current or voltage of each phase, as shown in Figure 7, the turn-off (Turn-off) of the switch (Turn-off) The larger the angle β, the smaller the average torque is smaller than β = 0 in FIG. 6, but the torque ripple can be reduced to reduce the noise / vibration.

As described above, in controlling the motor by setting the advance angle and the conduction angle of the motor according to the load conditions, the conduction angle is varied so as to set the conduction section to be long. The maximum torque can be used to the maximum, thereby improving the efficiency of the motor.

Claims (6)

In the inverter control apparatus, the position detection means for sensing the position of the rotor, and the reference signal to enable the on / off of the power switching element of the inverter by the position information and the direction control signal of the rotor detected from the position sensing means Drive signal generating means generated, conduction angle varying means for varying the advance and conduction angles of the drive signal according to the operating conditions of the load to use the magnetoresistive torque, and position information of the rotor transmitted from the position sensing means; A speed control means for detecting a speed by controlling the speed, controlling the speed of the motor by comparing with a pre-programmed target speed, pulse width modulation means for pulse width modulating the drive signal output from the drive signal generation means, and As a component of the inverter drive means for driving the inverter as a pulse width modulated drive signal from the pulse width modulation means A conduction angle control device of a buried type BDC motor. The buried type according to claim 1, wherein the conduction angle varying means determines the advance angle of the driving signal according to the magnitude of the load, and moves the conduction section by the determined advance angle to drive and control each phase. Conduction angle control device of BLDC motor. The method according to claim 1, wherein the conduction angle varying means determines the advance angle of the drive signal according to the magnitude of the load, and extends the conduction section by the determined advance angle to control the driving of each phase. Conduction angle control device for embedded DC motors. 4. The conduction angle control device of a buried type BDC motor according to claim 3, wherein the conduction angle variable means sets the conduction section long by time delay using an RC time constant. 4. The conduction angle control device of a buried type BDC motor according to claim 3, wherein the conduction section is set to be long in the variable angle of conduction means by using a device having a latch function such as flip-flop. [5] The buried type BLDC according to claim 3, wherein in the variable conduction angle, the conduction angle is set so that the conduction section is set to be long using a signal inputted with a pre-programmed calculated result from the microcomputer. The conduction angle control device of the motor.

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