KR102615144B1 - Apparatus and method for controlling of motor - Google Patents

Abstract

According to an embodiment of the present invention, a control unit sequentially aligns a motor in a stopped state to an electrical angle of 0 degrees, a reference angle, and 0 degrees; a detection unit that senses each back electromotive force response of the motors aligned according to the electrical angle; A motor control device is provided including a calculation unit that estimates the inertia and load of the motor according to the back electromotive force response.

Description

Motor control device and method {APPARATUS AND METHOD FOR CONTROLLING OF MOTOR}

The present invention relates to a motor control device and method, and more specifically, to a motor control device and method that can be applied to a BLDC (BrushLess Direct Current) motor.

BLDC motors use a commutation circuit consisting of switching elements instead of mechanical elements such as brushes and commutators. This BLDC motor does not require replacement of brushes due to wear and is characterized by low electromagnetic interference and low driving noise.

BLDC motors are powered by a power conversion device that converts commercial AC power into pulsed, multi-phase AC power (usually three phases). The control unit that controls the speed of the BLDC motor controls the rotation speed of the BLDC motor based on the phase current information of the multi-phase AC power supplied to the BLDC motor from the power conversion device and the position and speed information of the rotor. The control unit controls the rotation speed of the BLDC motor to follow the speed command input from the outside.

In order to derive optimal efficiency from a BLDC motor, the position of the rotor and the point of commutation of phase current must be precisely matched. For this purpose, a device for detecting the position of the rotor is required. Generally, a position detection sensor such as an encoder is used to detect the position of the rotor. Since the encoder is bulky and expensive, a method was sought to detect the position of the rotor using an electric circuit. As a result, the position of the rotor is detected through the zero crossing point of the back electromotive force of the motor. Electric circuits are widely used. An operation mode that detects the position of the rotor using an electric circuit instead of a position detection sensor such as an encoder is called sensorless operation mode.

For sensorless operation of a BLDC motor, a certain initial startup is required before starting sensorless operation. In other words, system initialization is performed to initialize the inverter and control variables, and two phases (in the case of a three-phase motor) are excited to force the rotor to be aligned. Once the rotor alignment is complete, synchronous acceleration of the motor is performed to increase the phase voltage and driving frequency to preset values. When the driving frequency and phase voltage reach a certain level due to synchronous acceleration, the operation mode is switched to detect the zero crossing point of the back electromotive force generated at this time while fixing the driving frequency and varying the phase voltage. Using the zero crossing point detected in this process, a sensorless operation mode is implemented that switches phase current and controls the rotation speed of the motor.

When such a BLDC motor is used as a cooling fan motor, the inertia and load applied to the BLDC motor vary depending on the shape of the installed fan, the number of blades, the thickness, and temperature and humidity of the radiator and condenser that make up the cooling module. In the case of sensorless BLDC motors, it is difficult to detect such changes, and when controlled with a single parameter, motor control may fail in high/low load situations of the changed motor, and may have a negative impact on noise, vibration, durability, etc. .

The technical problem to be achieved by the present invention is to provide a motor control device and method that enables stable motor control depending on the situation by estimating the inertia and load of the motor during driving and setting organic control parameters.

Additionally, the aim is to provide a motor control device and method that can minimize the negative effects of noise and vibration on the motor.

Additionally, the object is to provide a motor control device and method that can improve the durability of the motor.

According to an embodiment of the present invention, a control unit sequentially aligns a motor in a stopped state to an electrical angle of 0 degrees, a reference angle, and 0 degrees; a detection unit that senses each back electromotive force response of the motors aligned according to the electrical angle; A motor control device is provided including a calculation unit that estimates the inertia and load of the motor according to the back electromotive force response.

The calculation unit can calculate RPM slew-rate, driving Max Rpm, and speed controller gain parameters according to the estimated motor inertia and load.

The control unit may set the RPM slew-rate, driving Max Rpm, and speed controller gain parameters in a table, and perform synchronous acceleration of the motor according to the set table.

The reference angle may be 90 degrees or less.

When the motor is in a driving state, the inverter may apply a zero (0) vector to the motor under the control of the control unit to control the motor to a stopped state.

According to an embodiment of the present invention, sequentially aligning a motor in a stationary state to an electrical angle of 0 degrees, a reference angle, and 0 degrees; Sensing each back electromotive force response of the motors aligned according to the electrical angle; and estimating the inertia and load of the motor according to the back electromotive force response.

A step of calculating RPM slew-rate, driving Max Rpm, and speed controller gain parameters according to the estimated motor inertia and load may be further included.

Setting the RPM slew-rate, driving Max Rpm, and speed controller gain parameters in a table; and performing synchronous acceleration of the motor according to a set table.

The motor control device and method of the present invention can perform stable motor control depending on the situation by estimating the inertia and load of the motor during driving and setting organic control parameters.

Additionally, the negative effects of noise and vibration on the motor can be minimized.

Additionally, the durability of the motor can be improved.

1 is a configuration diagram showing the main configuration of a motor control device according to an embodiment of the present invention.
Figure 2 is a schematic diagram of the configuration of a motor according to an embodiment of the present invention.
Figure 3 is a diagram for explaining the inverter control operation of the control unit according to an embodiment of the present invention.
Figure 4 is a diagram for explaining a method for detecting the position of a motor rotor according to an embodiment of the present invention.
Figure 5 is a flowchart of a motor control method according to an embodiment of the present invention.

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

However, the technical idea of the present invention is not limited to some of the described embodiments, but may be implemented in various different forms, and as long as it is within the scope of the technical idea of the present invention, one or more of the components may be optionally used between the embodiments. It can be used by combining and replacing.

In addition, terms (including technical and scientific terms) used in the embodiments of the present invention, unless explicitly specifically defined and described, are generally understood by those skilled in the art to which the present invention pertains. It can be interpreted as meaning, and the meaning of commonly used terms, such as terms defined in a dictionary, can be interpreted by considering the contextual meaning of the related technology.

Additionally, the terms used in the embodiments of the present invention are for describing the embodiments and are not intended to limit the present invention.

In this specification, the singular may also include the plural unless specifically stated in the phrase, and when described as "at least one (or more than one) of A and B and C", it is combined with A, B, and C. It can contain one or more of all possible combinations.

Additionally, when describing the components of an embodiment of the present invention, terms such as first, second, A, B, (a), and (b) may be used.

These terms are only used to distinguish the component from other components, and are not limited to the essence, sequence, or order of the component.

And, when a component is described as being 'connected', 'coupled' or 'connected' to another component, the component is not only directly connected, coupled or connected to that other component, but also is connected to that component. It can also include cases where other components are 'connected', 'combined', or 'connected' due to another component between them.

Additionally, when described as being formed or disposed "above" or "below" each component, "above" or "below" refers not only to cases where two components are in direct contact with each other, but also to one This also includes cases where another component described above is formed or placed between two components. In addition, when expressed as "top (above) or bottom (bottom)", it may include not only the upward direction but also the downward direction based on one component.

Hereinafter, embodiments will be described in detail with reference to the attached drawings, but identical or corresponding components will be assigned the same reference numbers regardless of reference numerals, and duplicate descriptions thereof will be omitted.

1 is a configuration diagram showing the main configuration of a motor control device according to an embodiment of the present invention.

Referring to FIG. 1, the motor control device 100 according to the present invention may include an inverter 120, a detection unit 130, a calculation unit 140, and a control unit 150.

In an embodiment of the present invention, the motor 110 to be controlled has a rotor and receives power from the inverter 120 to rotate the rotor to provide rotational force. Here, the motor 110 includes a BLDC motor and may have a three-phase winding that generates an inductance component.

In other words, a BLDC motor is a structure that does not have an insulating conductor such as a carbon brush to transmit power. There is a magnet on the motor shaft and a coil on the inner wall of the motor case, so the power supply for the motor to rotate is inside the non-rotating motor. No brushes are required as it feeds into coils attached to the wall.

Figure 2 is a schematic diagram of the configuration of a motor according to an embodiment of the present invention. Referring to Figure 2, a motor according to an embodiment of the present invention may be configured to include a stator (3) and a rotor (5).

The stator 3 may be fixed within the housing 31 forming the outer body. The stator (3) is a driving part that generates a rotational driving force together with the rotor (5) mounted coaxially on the inside, and is a type of electromagnet that includes a stator core (25) that is fixed and mounted on the inner peripheral surface of the housing (31) by press fitting, etc. , It may be composed of a coil 33 wound on the stator core 25. The stator core 25 is a hollow cylindrical member as shown, and has a hole formed on the central axis into which the rotor 5 is inserted, and a plurality of ribs protrude radially inward on the inner peripheral surface of the stator core 25. They are arranged at regular intervals in the circumferential direction to form through holes, and the ribs extend long along the axial direction of the stator core 25 to wind the coil 33.

As mentioned above, the rotor 5 is a part that is coaxially mounted on the inside of the stator 3 and rotates, and can be rotatably inserted into the central hole of the stator core 25 of the stator 3. The rotor 5 may be composed of a rotating shaft 37 arranged long along the central axis and a permanent magnet 27 attached to the outer peripheral surface of the rotating shaft 37. The permanent magnets (27) are arranged with two N and S poles alternately at 90° intervals around the rotation axis (37), and the rotor (5) moves the stator according to the driving principle of the motor when the stator (3) is excited. Rotation can be driven by interaction with (3).

Referring again to FIG. 1, the inverter 120 may convert direct current voltage into three-phase alternating current voltage and supply it to the motor 110. In the inverter 120, each power switching element (S1 to S6) is connected to the three-phase (U, V, W) winding as shown in FIG. 3. That is, the inverter 120 may include a three-phase switching element, for example, an upper three-phase FET and a lower three-phase FET.

In an embodiment of the present invention, when the motor is in a driving state, the inverter 120 may control the motor to a stopped state by applying a zero (0) vector to the motor under the control of the control unit.

The detection unit 130 can sense each back electromotive force response of the motors aligned according to the electrical angle. The detector 130 can measure the back electromotive force of each phase (U, V, W) from the 3-phase output terminal of the 3-phase inverter 120. The detection unit 130 may be configured to include voltage and current detection sensors. For example, the detection unit 130 may be configured to include at least one of a current transformer and a transformer.

Additionally, the detector 130 can detect the phase current of the motor. The detection unit 130 can measure the phase current generated when the zero vector is applied.

The calculation unit 140 may estimate the inertia and load of the motor according to the back electromotive force response. Back electromotive force is proportional to magnetic flux and rotation speed.

The calculation unit 140 may calculate RPM slew-rate, driving Max Rpm, and speed controller gain parameters according to the estimated motor inertia and load.

The control unit 150 can sequentially align the motor in a stopped state to an electrical angle of 0 (zero) degrees, then to a reference angle, and then to an electrical angle of 0 degrees. In embodiments of the present invention, the reference angle may be 90 degrees or less.

Additionally, the control unit 150 can set the RPM slew-rate, driving Max Rpm, and speed controller gain parameters in a table, and perform synchronous acceleration of the motor according to the set table.

Additionally, the control unit 150 can control the inverter to apply a zero (0) vector to the motor. The control unit 150 turns on all three-phase switches at the top of the inverter 120, or turns on all three-phase switches at the bottom of the inverter 120, so that the zero vector becomes the motor It can be controlled to be applied to (100).

Figure 3 is a diagram for explaining the inverter control operation of the control unit according to an embodiment of the present invention.

Referring to Figures 1 and 3, the inverter 120 according to the present invention has each power switching element FET (S1 to S6) connected to the three-phase (U, V, W) winding.

At this time, power factor correction capacitors 210 may be connected in parallel on the connection line between the inverter unit 120 and the three-phase winding of the motor 110, respectively. That is, three power factor correction capacitors 210 may be connected in parallel among the three phases at the output terminal of the inverter 120: between the U phase and the V phase, between the V phase and the W phase, and between the W phase and the U phase. Additionally, the capacity size of the power factor correction capacitor 210 may be set to remain the same as the size of the inductance component of the motor 110.

The control unit 150 applies a switching drive signal of each power switching element (S1 to S6) to the inverter 120. That is, the control unit 150 controls the starting, operation, and speed of the motor 110 by controlling the switching operation of each switching element (S1 to S6) of the inverter 120 according to the user's operation, and each switching element ( A switching drive signal for switching S1 to S6) is generated and applied to the inverter 120.

The control unit 150 turns on all three-phase switches at the top of the inverter 120, or turns on all three-phase switches at the bottom of the inverter 120, so that the zero vector becomes the motor 100. It can be controlled to be applied to .

Additionally, the control unit 150 may estimate rotor position information from the back electromotive force information of the motor 110, and control the switching of phase current and the rotation speed of the motor according to the estimated rotor position information. The control unit 150 is electrically connected to the outside of the stator and can drive or stop the rotor to rotate by demagnetizing the stator.

The motor control device 100 according to an embodiment of the present invention is provided by applying it to a cooling fan for cooling a heat exchanger including a motor rotor provided in the motor 110 and a fan connected to the rotation axis of the motor rotor. It can be.

Figure 4 is a diagram for explaining a method for detecting the position of a motor rotor according to an embodiment of the present invention.

Referring to Figure 4, the back electromotive force generated from the stator coil of each phase is extracted when the motor rotates, and the zero crossing (ZC) point of the back electromotive force is used to estimate the position information of the rotor and the switching point of each phase current. can do.

In the high-speed section, the detector measures the voltage of the three-phase (U-phase, V-phase, and W-phase) terminals to obtain the back electromotive force, calculates the neutral point as the average value of the back electromotive force, and obtains the ZC point where the neutral point and the back electromotive force intersect.

Since the ZC point occurs 6 times per electrical rotation (360°) of the BLDC motor, it serves as the basis for detecting the position at 60° intervals, so the position can be detected using the ZC point.

Figure 5 is a flowchart showing a control method of a brushless direct current motor according to an embodiment of the present invention, showing the control method from initial startup of the brushless direct current motor to conversion to sensorless operation mode.

First, for sensorless operation of a BLDC motor, a certain initial startup is required before starting sensorless operation. That is, system initialization is performed to initialize the inverter and control variables (S501).

Next, current is supplied to any two phases of the motor to align the rotor position. That is, if the brushless direct current motor has three phases, two of them are excited to force the rotor to align (S502). In the alignment process, the control unit aligns the motor at rest to an electrical angle of 0 (zero) degrees, then aligns it to a reference angle, and then sequentially aligns the electric angle to 0 degrees, and the detector detects the motors aligned according to the electrical angle. Each back electromotive force response is sensed. The calculation unit estimates the inertia and load of the motor according to the back electromotive force response, and sets parameters such as RPM slew-rate, driving Max Rpm, and speed controller gain in the table according to the estimated inertia and load of the motor.

Next, the magnitude of the phase voltage applied to the motor and the driving frequency are varied to accelerate and rotate the rotor of the motor to a constant speed. In other words, when the alignment of the rotor is completed, synchronous acceleration of the motor is performed to increase the phase voltage and driving frequency to a preset value (S503). At this time, the control unit performs synchronous acceleration using the table set in step S502.

Next, when the driving frequency and the voltage reach a preset value, the driving frequency is fixed and the phase voltage is varied. That is, when the driving frequency and phase voltage reach a certain level due to synchronous acceleration, the driving frequency is fixed and the phase voltage is varied (S504).

Next, rotor position information is estimated from the back electromotive force information of the motor. That is, position information is estimated using the zero crossing point of the back electromotive force generated when the phase voltage varies (S505).

Next, the transition of phase current and the rotation speed of the motor are controlled according to the estimated rotor position information. In other words, a sensorless operation mode is implemented that switches the phase current and controls the rotation speed of the motor according to the rotor position information (S506).

The term '~unit' used in this embodiment refers to software or hardware components such as FPGA (field-programmable gate array) or ASIC, and the '~unit' performs certain roles. However, '~part' is not limited to software or hardware. The '~ part' may be configured to reside in an addressable storage medium and may be configured to reproduce on one or more processors. Therefore, as an example, '~ part' refers to components such as software components, object-oriented software components, class components, and task components, processes, functions, properties, and procedures. , subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and variables. The functions provided within the components and 'parts' may be combined into a smaller number of components and 'parts' or may be further separated into additional components and 'parts'. In addition, the components and 'parts' may be implemented to regenerate one or more CPUs within the device or secure multimedia card.

Although the present invention has been described above with reference to preferred embodiments, those skilled in the art may make various modifications and changes to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. You will understand that you can do it.

100: motor control device
110: motor
120: inverter
130: detection unit
140: Calculation unit
150: control unit

Claims (9)

A control unit that sequentially aligns the motor in a stopped state to an electrical angle of 0 (zero) degrees, then to a reference angle, and then to the electrical angle of 0 degrees;
a detection unit that senses each back electromotive force response of the motors aligned according to the electrical angle; and
It includes a calculation unit that estimates the inertia and load of the motor according to the back electromotive force response,
The calculation unit calculates RPM slew-rate, driving Max Rpm, and speed controller gain parameters according to the estimated motor inertia and load,
The control unit sets the RPM slew-rate, driving Max Rpm, and speed controller gain parameters in a table, and performs synchronous acceleration of the motor according to the set table.
delete delete According to paragraph 1,
A motor control device wherein the reference angle is 90 degrees or less.
According to paragraph 1,
A motor control device further comprising an inverter that controls the motor in a stopped state by applying a zero (0) vector to the motor under the control of the control unit when the motor is in a driving state.
Aligning the motor in a stopped state to an electrical angle of 0 (zero) degrees, then aligning it to a reference angle, and then sequentially aligning the motor to the electrical angle of 0 degrees;
Sensing each back electromotive force response of the motors aligned according to the electrical angle;
estimating inertia and load of the motor according to the back electromotive force response;
Calculating RPM slew-rate, driving Max Rpm, and speed controller gain parameters according to the estimated motor inertia and load;
Setting the RPM slew-rate, driving Max Rpm, and speed controller gain parameters in a table; and
A motor control method comprising performing synchronous acceleration of the motor according to a set table.
According to clause 6,
A motor control method wherein the reference angle is 90 degrees or less.
According to clause 6,
Before the step of aligning, when the motor is in a driving state, the inverter applies a zero (0) vector to the motor under the control of a control unit to control the motor to a stopped state.

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