KR100984251B1 - Blcd motor controller based on maximum power algorithm - Google Patents

Abstract

The present invention relates to a BLDC motor control apparatus using a maximum output algorithm, and more particularly, to improve the output performance of the three-phase two-excitation type BLDC motor by extending the conduction angle within the maximum conduction angle to reduce the torque of the BLDC motor The present invention relates to a BLDC motor control apparatus using a maximum output algorithm capable of generating a maximum torque.

BLDC, PWM, Torque, 3-Phase 2 Excitation, Through Angle

Description

BLCD MOTOR CONTROLLER BASED ON MAXIMUM POWER ALGORITHM}

The present invention relates to a BLDC motor control apparatus using a maximum output algorithm, and more particularly, to improve the output performance of the three-phase two-excitation type BLDC motor by extending the conduction angle within the maximum conduction angle to reduce the torque of the BLDC motor The present invention relates to a BLDC motor control apparatus using a maximum output algorithm capable of generating a maximum torque.

Recently, the development and application of variable speed systems using inverter technology in the constant speed operation mode have been actively performed according to the reduction of energy consumption of home appliances, the increase in the demand for low noise, the development of power electronic technology, and the reduction of the cost of power electronic components.

BLDC (BRUSHLESS DC) motor is a motor that rotates the rotor by forming a stator with a non-contact method to the rotor provided with a permanent magnet to prevent the brush from being damaged by repeated friction when using a conventional DC motor Was developed to.

In addition, since the BLDC motor speed control is easy, and high efficiency, large starting torque, small size and light weight are possible, it is actively applied to the variable speed system.

On the other hand, the BLDC motor has a trapezoidal counter electromotive force waveform, and for a constant torque output, a constant current must be flowed at a conduction angle of 120 degrees.

As described above, in order to input each phase current at a conduction angle of 120 degrees, PWM is controlled so that only two phase currents can flow at all times according to the rotor position of the BLDC converter, and the other phase is a two phase that maintains an open state. Use the female method.

However, the three-phase two-excitation method has superior advantages in terms of pulsating torque compared to the 180-degree driving method, but the winding utilization rate of the motor is low at about 66.7%, resulting in low overall system output.

The present invention has been devised to solve the above problems, and an object of the present invention is to control a BLDC motor in a three-phase two-excitation manner, so that torque can be increased while extending the conduction angle, while torque ripple is reduced. To provide a BLDC motor controller using the maximum output algorithm that can be made.

BLDC motor control apparatus using the maximum output algorithm according to an embodiment of the present invention for achieving the above object is a rotation angle measuring unit for measuring the rotation angle of the rotor of the BLDC motor, receives the rotation angle of the rotor Calculating the actual speed of the rotor, comparing the actual speed and the command speed and outputs a speed difference value, receives the speed difference value and calculates the command current according to the speed difference value, 120 A current control unit for generating the first PWM signal by modulating the command current at a conduction angle of degrees; when the command current exceeds the rated current of the BLDC motor, the conduction angle is extended within the maximum conduction angle; An electric conduction angle expansion unit for generating a second PWM signal by modulating the rated current with an extended electric conduction angle and receiving the PWM signals to each phase of the BLDC motor. It includes a gate driver to transfer.

In a preferred embodiment, the current controller is a speed controller for receiving the speed difference value and outputting the command current, the magnitude of the command current is compared with the magnitude of the rated current of the BLDC motor, the magnitude of the command current is An excess current circuit breaker that outputs a conduction angle control start signal when the magnitude of the rated current is greater than or greater than the magnitude of the rated current, and modulates the command current at a conduction angle of 120 degrees to generate the first PWM signal; And a first PWM generator.

In a preferred embodiment, the energization angle expansion unit is an energization angle control start switch 'on' by the energization angle control start signal, when the energization angle control start switch is 'on' current by comparing the rated current and the command current Rated current comparator for outputting a difference value, a conduction angle controller for extending the conduction angle of 120 degrees in accordance with the current difference value, the conduction angle controller, a maximum conduction angle breaker to allow the extended conduction angle to extend only up to the conduction angle And a second PWM generator configured to output the second PWM signal by modulating the rated current with the extended conduction angle.

In a preferred embodiment, the maximum conduction angle is 130 degrees to 140 degrees.

In a preferred embodiment, the maximum conduction angle is 136 degrees.

As described above, according to the present invention, in controlling the BLDC motor in a three-phase two-excitation method, motor control using a maximum output algorithm that can improve the output of the BLDC motor by extending the conduction angle of 120 degrees below the maximum conduction angle. A device can be provided.

In addition, according to the present invention, when the command current for the torque to be obtained is less than the rated current of the BLDC motor to control the conduction angle of 120 degrees to reduce the occurrence of pulsating torque, when the command current exceeds the rated current within the maximum conduction angle It is possible to provide an electric motor controller using a maximum output algorithm that can increase the torque by about 28%.

In addition, according to the present invention, it is possible to provide a BLDC motor control apparatus using a maximum output algorithm that can reduce the torque ripple.

Prior to describing an embodiment of the present invention with reference to the drawings, a brief description will be given of the driving principle of the BLDC motor.

Equation 1 below represents the equivalent circuit of the BLDC motor as a voltage equation.

Where R and L are the resistance and leakage inductance of each phase, and V _a , V _b , and V _c are terminal voltages of each phase, as seen from the reference of the DC voltage source, and e _a , e _b , e _c and i _a , i _b , i _c is the counter electromotive force and phase current of each phase.

In addition, V _n is the neutral point voltage inside the BLDC motor as seen from the DC voltage source. If the resistance and the leakage inductance of each phase are the same, the sum of the phase currents is always 0 when the neutral point of the BLDC motor is not used. It can be expressed by Equation 2.

Here, the counter electromotive force e of each phase may be expressed by Equation 3 below.

Where K _e is the counter electromotive force constant and ω _m is the angular velocity of the BLDC motor rotor.

In addition, f (θ) is a function of normalizing the counter electromotive force of each phase according to the position of the rotor.

Here, given each phase current and counter electromotive force, the electrical torque generated in the BLDC motor can be obtained as shown in Equation 4 below.

As can be seen in Equation 4, in the conventional control method of a BLDC motor using a 120 degree conduction angle, there are always two terms among the three terms of the torque equation, and each term is an effective application by the position function of the rotor. The rate is always 2/3.

Therefore, in order to control the torque of the BLDC motor, the magnitude of the current is controlled.

Here, if the conduction angle θ _d is changed, the terms of the torque equation by each phase can be expressed by the effective ratio of the rotor position function, and are always θ _d / π.

In other words, it can be seen that the torque can be controlled by controlling the energization angle.

However, increasing the conduction angle increases the effective application rate, but may result in a reduction in torque.

Therefore, it is necessary to increase the conduction angle within an area below the maximum conduction angle that can increase or decrease the torque.

In addition, when the conduction angle is enlarged closer to 180 degrees below the rated torque, the pulsating torque is larger than that of the conventional 120 degree conduction angle, and the copper loss is also large.

That is, in one embodiment of the present invention outputs a PWM signal at a 120 degree conduction angle below the rated torque by the rated current of the BLDC motor, and extends the conduction angle to 120 degrees or more to increase the output above the rated torque The BLDC motor controller is constructed using a new maximum output algorithm that controls torque.

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

1 is a block diagram of a BLDC motor control apparatus using a maximum output algorithm according to an embodiment of the present invention.

Referring to FIG. 1, a BLDC motor control apparatus using a maximum output algorithm according to an embodiment of the present invention includes a rotation angle measuring unit 100, a rotation speed comparison unit 200, a current control unit 300, and an energization angle extension unit. 400 and the gate driver 500.

The rotation angle measuring unit 100 measures the rotation angle of the rotor (not shown) provided in the BLDC motor 10.

In addition, the rotation angle measuring unit 100 is a rotation angle of the rotor based on the amount of current output from the Hall sensor 110 and the Hall sensor 110 outputs a predetermined amount of current in accordance with the rotation of the rotor. It includes an angle sensor 120 to calculate.

On the other hand, since the Hall sensor 110 provided in the rotation angle measuring unit 100 is sufficient to detect the rotation position of the rotor, it can be replaced by an encoder using a photodiode or a magnetoresistive element.

The rotational speed comparison unit 200 receives the rotational angle, calculates an actual speed (ω) which is an actual rotational speed of the rotor, and a commanding speed for rotating the actual speed (ω) and the rotor. By comparing (ω *), a speed difference value that is a difference between the actual speed (ω) and the command speed (ω *) is output.

In addition, the rotational speed comparison unit 200 compares the actual speed and the command speed with the speed sensor 210 for calculating the rotational speed of the rotor based on the rotational angle output from the angle sensor 120 It comprises a rotation speed comparator 220.

The current controller 300 receives the speed difference value, calculates a command current i * for correcting the speed difference value to the command speed, and modulates the command current i * at a conduction angle of 120 degrees. Generate a first PWM signal.

In addition, the current controller 300 receives the speed difference value and outputs the command current (i *), the speed controller 310, the command current (i *) is the rated torque of the BLDC motor, that is, the rated When the rated current I _rate for outputting torque is exceeded, the magnitude of the excess current breaker 320 and the command current i * outputting the conduction angle control start signal is equal to or less than the magnitude of the rated current I _rate . In this case, a first PWM generator 330 is configured to generate the first PWM signal by modulating the command current i * at a conduction angle of 120 degrees.

That is, when the command current i * is less than the rated current I _rate , the current controller 300 modulates the command current i * at a conduction angle of 120 degrees to generate a first PWM signal. This is to reduce the pulsating torque of the BLDC motor 10.

The conduction angle expansion unit 400 extends the conduction angle of 120 degrees within the maximum conduction angle when the command current (i *) exceeds the rated current (I _rate ) and the rated current (I _rate ). Modulates the extended conduction angle to output a second PWM signal.

On the other hand, the maximum conduction angle is obtained by the equation (4), Figure 2 is a torque graph of the BLDC motor according to the conduction angle of the BLDC motor control apparatus using the maximum output algorithm according to an embodiment of the present invention.

Referring to FIG. 2, when the energization angle of the BLDC motor control apparatus using the maximum output algorithm according to the exemplary embodiment of the present invention is 136 degrees, the torque is increased by about 28% compared with the 120 degree angle, and the energization angle is increased at more energization angles. Despite this, the generated torque decreased.

In particular, it can be seen that when the conduction angle is 146 degrees or more, a torque lower than the conduction angle of 120 degrees occurs.

Therefore, in one embodiment of the present invention, the maximum conduction angle was set to 136 degrees.

In addition, when the energization angle control start switch 410 and the energization angle control start switch 410 are 'on' the command current is 'on' by the energization angle control start signal. Rated current comparator 420 for outputting a current difference value that is the difference between (i *) and the rated current (I _rate ), through the conduction angle of the 120 degree constant angle so that the torque value according to the current difference value can be output An electric conduction angle controller 430 that extends full width, a maximum conduction angle breaker 440 that controls the extended conduction angle so as not to deviate from the maximum conduction angle, and modulates the rated current I _rate by the extended conduction angle. And a second PWM generator 440 for outputting two PWM signals.

In addition, the PWM generators 330 and 450 may be provided as one PWM generator, and the second PWM generator 450 may extend only the conduction angle of the first PWM signal generated by the first PWM generator 330. It may be configured in a manner that gives.

The gate driver 500 transmits the PWM signals to each phase of the BLDC motor 10 to allow the rotor of the BLDC motor 10 to rotate.

That is, in the BLDC motor control apparatus using the maximum output algorithm according to an embodiment of the present invention, when the command current i * is equal to or less than the rated current I _rate , the pulsation torque is reduced by setting the conduction angle to 120 degrees, and the command When the current (i *) exceeds the rated current (I _rate ) it is possible to compensate for the disadvantages of output reduction of the conventional three-phase two-excitation method by increasing the torque by extending the conduction angle.

3 is a view showing an angle waveform according to an energization angle of a BLDC motor control apparatus using a maximum output algorithm according to an embodiment of the present invention.

In addition, (a) of FIG. 3 shows a conduction angle signal with time, (b) shows the phase current waveform with time, and (c) shows the waveform of instantaneous torque.

Referring to the drawings, the ripple factor of the torque (Torque ₁₂₀₎ in the barrel of 120 degrees full size is, compared to approximately 14.95%, barrel em 136 ripple rate of degrees when the torque (Torque ₁₃₆₎ significantly the torque ripple to about 5.54% It can be seen that the decrease.

In addition, it can be seen that the torque (Torque ₁₃₆ ) at the conduction angle of ₁₃₆ degrees increased about 28% than the torque (Torque ₁₂₀ ) at the conduction angle of 120 degrees.

On the other hand, when the conduction angle is 152 degrees, the effective value (i ₁₅₂ ) of the current is increased than the effective value (i ₁₂₀ ) of the current at the 120 degree conduction angle, it can be seen that the torque ( ₁₅₂ ) is rather reduced.

That is, the BLDC motor control apparatus using the maximum output algorithm according to an embodiment of the present invention can be seen that the output is increased by about 28% than the conventional 120-degree conduction angle control method, the torque ripple rate is reduced to 5.54% Able to know.

In the above, the configuration and operation of the present invention has been shown in accordance with the above description and drawings, but this is merely described, for example, and various changes and modifications are possible without departing from the spirit and scope of the present invention. .

1 is a block diagram of a BLDC motor control apparatus using a maximum output algorithm according to an embodiment of the present invention,

2 is a torque graph of a BLDC motor according to an energization angle of a BLDC motor control apparatus using a maximum output algorithm according to an embodiment of the present invention;

3 is a view showing an angle waveform according to an energization angle of a BLDC motor control apparatus using a maximum output algorithm according to an embodiment of the present invention.

In the drawings according to the present invention, the same reference numerals are used for components having substantially the same configuration and function.

<Description of the symbols for the main parts of the drawings>

100: rotation angle measurement unit 110: Hall sensor

120: angle sensor 200: rotational speed comparison unit

210: speed sensor 220: rotational speed comparator

300: current controller 310: speed controller

320: overcurrent breaker 330: first PWM generator

400: conduction angle expansion unit 410: conduction angle control start switch

420: rated current comparator 430: conduction angle controller

440: Maximum conduction angle breaker 450: Second PWM generator

500: gate driver

Claims (5)

delete delete Rotation angle measuring unit for measuring the rotation angle of the rotor of the BLDC motor; A rotation speed comparator configured to receive the rotation angle of the rotor, calculate an actual speed of the rotor, and output a speed difference value by comparing the actual speed with a command speed; A current controller configured to receive the speed difference value, calculate a command current according to the speed difference value, and modulate the command current at a conduction angle of 120 degrees to generate a first PWM signal; When the command current exceeds the rated current of the BLDC motor, the conduction angle is extended to 120 degrees, and after obtaining the maximum conduction angle which is the conduction angle at which the torque of the BLDC motor is maximum using the following equation, A conduction angle expansion unit configured to expand the 120 degree conduction angle so as not to exceed the maximum conduction angle, and generate a second PWM signal by modulating the rated current with the extended conduction angle; And [Equation]

(Where e is the counter electromotive force of each phase, i is the phase current of each phase, K _e is the counter electromotive force constant, ω _m is the BLDC motor rotor, and f (θ) is a function that normalizes the counter electromotive force of each phase according to the position of the rotor.) A gate driver configured to receive the PWM signals and transfer them to each phase of the BLDC motor; The current control unit: A speed controller configured to receive the speed difference value and output the command current; An excess current breaker for outputting an energization angle control start signal when the magnitude of the command current exceeds the magnitude of the rated current by comparing the magnitude of the command current with the magnitude of the rated current of the BLDC motor; And And a first PWM generator configured to generate the first PWM signal by modulating the command current at a conduction angle of 120 degrees when the magnitude of the command current is equal to or less than the magnitude of the rated current. The conduction angle extension: An energization angle control start switch 'on' by the energization angle control start signal; A rated current comparator for outputting a current difference value by comparing a rated current with a command current when the energization angle control start switch is 'on'; A conduction angle controller for extending the conduction angle of 120 degrees to a conduction angle of a predetermined angle according to the current difference value; A maximum conduction angle breaker for allowing the extended conduction angle to extend only up to a maximum conduction angle; And And a second PWM generator for outputting the second PWM signal by modulating the rated current with the extended conduction angle. The method of claim 3, wherein The maximum conduction angle is BLDC motor control apparatus using a maximum output algorithm, characterized in that 130 degrees to 140 degrees. The method of claim 4, wherein BLDC motor control apparatus using the maximum output algorithm, characterized in that the maximum conduction angle is 136 degrees.

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