KR101796948B1 - Sensorless controlling method of an electric motor - Google Patents

Abstract

The present invention relates to a sensorless control method of a driving unit of a BLDC motor. When an error signal reception from the sensing unit 7 is confirmed in an error checking step S130, a signal received from the sensing unit 7 is ignored, A sensorless control step (S140) of controlling the rotor (5) by a control unit (9) according to a lease method; If the operation signal of the rotor 5 is received during the deceleration of the rotor 5 in the deceleration control step S150 in operation S161 and the normal signal other than the error signal received from the sensing unit 7 A gain value estimating step (S160) of estimating a variable (k) gain value of the control algorithm according to the sensorless method by the control unit 9 (S162); And restarting the control of the rotor (5) in a sensorless manner according to the gain value of the variable (k). In the sensorless control method of the present invention, There is no problem in estimating the position of the rotor for restarting the operation after the deceleration or operation stop command is input in the state of controlling in the lease mode, and when the drive stop command is momentarily inputted and then disappears, The driving efficiency of the driving unit can be further improved.

Description

[0001] The present invention relates to a sensorless control method of an electric motor,

The present invention relates to a sensorless control method for a BLDC motor, and more particularly, to a sensorless control method for a BLDC motor in which, when a rotation of a driving unit is sensed by a sensing unit such as a Hall sensor, To a sensorless control method of a BLDC motor that can maintain a normal state of the motor.

Generally, a BLDC motor is a brushless motor of a DC motor. Unlike a general DC motor in which a rotor is an electromagnet and a stator is a permanent magnet, , The rotor 103 is a permanent magnet and the outer stator 105 is an electromagnet.

However, since the BLDC motor 101 maintains the characteristics of a general DC motor as it is, the starting torque is large, the rotation characteristic is linearly proportional to the applied voltage, and therefore, the output efficiency is good. On the other hand, The position of the magnetic flux of the rotor 103 can not be known, unlike a general DC motor in which the positions of the magnetic fluxes of the electrons and the stator are kept constant. 1, the BLDC motor 101 is rotated by the sensing unit 107 composed of a plurality of Hall sensors Ha, Hb, and Hc continuously arranged in the circumferential direction on one side of the inner peripheral surface of the stator 105, The position of the magnetic fluxes of the rotor 103 and the stator 105 is adjusted by sensing the rotation of the electron 103 and determining the exact position of the rotor 103 to control the current of the core 109 of the stator 105 So that a rotating torque is generated between the rotor 103 and the stator 105.

That is, the BLDC motor 101 has a rectifying system that is electronically controlled and is of a synchronous motor type that is powered by direct current. In order to continuously rotate the rotor 103 in one direction, The direction of the current flowing in each phase of the coil of the stator 105 is switched according to the position of the rotor 103 detected by the detection unit 107, The rotor 103 must be turned on and off sequentially. For this purpose, a three-phase signal having a phase difference of 120 degrees formed by a magnetic field is detected by the sensing part 107 so that the accurate position of the rotor 103 can be grasped.

At this time, the hall sensors Ha, Hb, and Hc constituting the sensing unit 107 are not only easily damaged, but also easily generate errors due to external factors such as temperature. Such an error is caused by the failure of the BLDC motor 101 Conventionally, the control method of the BLDC motor is switched to a sensorless control method that does not use the Hall sensors Ha, Hb, and Hc.

However, when the BLDC motor is controlled in a sensorless manner, for example, when an abnormal situation such as an excessive or an undervoltage is applied, the BLDC motor may be damaged due to various reasons such as lowering the rotation speed The BLDC motor is a synchronous motor which must find the synchronization point to perform the deceleration control and resume the operation. That is, in the case of the sinusoidal sensorless method applied to the engine cooling fan motor Unlike a general motor employing a square-wave sensorless method, the rotation of the rotor is reduced to 0 rpm in order to find a synchronization point, and the operation is completely stopped. Then, the electric quantity is measured by a high-frequency signal injection method or a fundamental wave excitation method Thereby estimating the position and velocity of the rotor.

However, the fundamental wave excitation method has a disadvantage that it can not be applied at a low speed for continuous operation because the counter electromotive force of the permanent magnet is very low. In addition, the high frequency signal injection method has a limitation on the additional voltage required for signal injection, There is a drawback that it can cause damage.

Disclosure of the Invention The present invention has been conceived in order to solve the problems of the conventional BLDC motor as described above. The present invention switches the control of the driving unit to the sensorless algorithm by the malfunction of the sensing unit such as the hall sensor for monitoring the rotation of the BLDC motor, In order to estimate the position of the rotor in order to improve the driving efficiency of the driving unit by improving the response of the BLDC motor to the deceleration or stop command inputted without being affected by the speed of the rotor or generating a load on the motor It has its purpose.

In order to achieve the above object, the present invention provides a stator comprising a stator having a coil wound inside a stator core fixed in a housing constituting an outer body, a rotor including a permanent magnet rotatably mounted coaxially inside the stator, And a controller for controlling the rotation of the rotor according to rotation information of the rotor transmitted from the sensing unit, A sensor initializing step of initializing the sensing unit as the driving of the BLDC motor is started; A sensor monitoring step of monitoring the rotation of the rotor by the sensing unit initialized in the sensor initializing step; An error checking step of checking, by the controller, an error signal received from the sensing unit during the rotor monitoring by the sensing unit in the sensor monitoring step; A sensorless control step of, when the reception of the error signal from the sensing unit is confirmed in the error checking step, the control unit ignores the signal received from the sensing unit and controls the rotor according to the sensorless method; A deceleration control step of decelerating the rotor by the control unit when an operation stop signal is received by the control unit while the rotor is being controlled according to a sensorless method in the sensorless control step; Determining whether the rotational speed of the rotor decelerated in the deceleration control step is 0, and estimating a reference position of the rotor when the rotational speed is 0; And a sensorless control step of resuming the sensorless control step according to an operation signal after the reference position of the rotor is confirmed in the rotor position estimation step, and a sensorless control method of the BLDC motor do.

According to another aspect of the present invention, there is provided a stator comprising: a stator having a coil wound inside a stator core fixed in a housing constituting a body; a rotor including a permanent magnet coaxially mounted inside the stator; And a controller for controlling the rotation of the rotor according to the rotation information of the rotor transmitted from the sensing unit. The BLDC motor includes a sensing unit for sensing the rotation of the rotor, A driving control method, comprising: a sensor initialization step of initializing a sensing unit according to a start of driving of a BLDC motor; A sensor monitoring step of monitoring the rotation of the rotor by the sensing unit initialized in the sensor initializing step; An error checking step of checking, by the controller, an error signal received from the sensing unit during the rotor monitoring by the sensing unit in the sensor monitoring step; A sensorless control step of, when the reception of the error signal from the sensing unit is confirmed in the error checking step, the control unit ignores the signal received from the sensing unit and controls the rotor according to the sensorless method; A deceleration control step of decelerating the rotor by the control unit when an operation stop signal is received by the control unit while the rotor is being controlled according to a sensorless method in the sensorless control step; Wherein when the rotor operation signal is received during the deceleration control of the rotor in the deceleration control step, the variable gain value of the control algorithm according to the sensorless method is set to the variable gain value of the control algorithm through the normal signal other than the error signal received from the sensing unit A gain value estimation step of estimating by a control unit; And a sensorless control resumption step of restarting the rotor control by the sensorless control of the sensorless control step according to the variable gain value estimated in the gain value estimation step. A sensorless control method of a driving unit is provided.

Therefore, according to the sensorless control method of the BLDC motor of the present invention, a sensing unit such as a Hall sensor which easily causes damage or failure due to external influences such as impact or temperature causes a malfunction in monitoring the rotation of the driving unit of the BLDC motor, In order to estimate the position of the rotor in order to resume the operation even if the deceleration or stop command is inputted while the control of the sensorless algorithm is switched to the sensorless algorithm, In addition to being able to re-drive the BLDC motor, even if the input stop command immediately disappears and the drive command is input again, the rotor speed information is received by some normal Hall sensors, k), it is possible to completely stop the BLDC motor for rotor position estimation Package can restart without it is possible to enhance the driving efficiency of the driving First.

1 is a view schematically showing a conventional BLDC motor.
2 is a schematic cross-sectional view of a BLDC motor to which the sensorless control method of the BLDC motor of the present invention is applied.
3 is a flowchart illustrating a sensorless control method of a BLDC motor according to an embodiment of the present invention.
FIG. 4 is a table showing a sensor sensing signal used in the sensorless control method of the BLDC motor shown in FIG.
5 is a graph showing changes in rotational speed of the rotor controlled by the sensorless control method of the BLDC motor shown in FIG.
6 is a flowchart illustrating a sensorless control method of a BLDC motor according to another embodiment of the present invention.
FIG. 7 is a graph showing changes in rotational speed of the rotor controlled by the sensorless control method of the BLDC motor shown in FIG. 6 with time. FIG.

Hereinafter, a sensorless control method of a BLDC motor according to an embodiment of the present invention will be described with reference to the accompanying drawings.

1, a BLDC motor to which the sensorless control method of a BLDC motor of the present invention is applied includes a stator 3, a rotor 5, (7), and a control unit (9).

2, the stator 3 is fixed in the housing 31 constituting the outer body, and the stator 3 is mounted coaxially on the inner side of the housing 31. In this case, 2, a stator core 25 which is fixedly mounted on the inner circumferential surface of the housing 31 by press fitting or the like, as a kind of electromagnet, as shown in Fig. 2, 25). As shown in the figure, the stator core 25 is a hollow cylindrical member and has a through hole through which the rotor 5 is inserted on the central axis. A plurality of ribs are radially inwardly formed on the inner circumferential surface of the stator core 25 And the ribs are elongated along the axial direction of the stator core 25 in order to wind the coils 33. The ribs are formed in the shape of a cylinder.

2, the sensing unit 7 senses the rotation of the rotor 5 and includes a plurality of hall sensors Ha (i) arranged continuously in the circumferential direction on one side of the inner circumferential surface of the core 25, , Hb, Hc).

2, the stator core 25 of the stator 3 is rotatably mounted on the inside of the stator 3, as described above, The permanent magnet 27 is rotatably inserted into the central through hole and comprises 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. In this case, 2, two N-poles and S-poles are alternately arranged at intervals of 90 degrees around the rotation axis 37. Therefore, the rotor 5 is arranged so that the stator 3 is excited by the driving principle of the motor And is driven to rotate by interaction with the stator 3.

2, the control section 9 is electrically connected to the outside of the stator 3 so as to remove the stator 3 so as to rotate the stator 3. As a result, The electron 5 is rotated or stopped.

Therefore, the BLDC motor 1 configured as described above is controlled by the sensorless control method of the BLDC motor according to the embodiment of the present invention. As shown in FIG. 3, The sensor monitoring step S20, the error checking step S30, the sensorless controlling step S40, the deceleration controlling step S50, the rotor position estimating step S60, and the sensorless control resuming step S70 .

3, the sensor initializing step S10 initializes the sensing unit 7 and includes a step S11 of confirming the operation of the BLDC motor 1 and a step S11 of checking the operation of the sensing unit 7, (S12). When it is confirmed that the driving of the BLDC motor 1 is started (S11), the sensing unit 7, that is, a plurality of Hall sensors Ha, Hb and Hc are initialized (S12).

The sensor monitoring step S20 is a step of monitoring whether an error signal is received through the sensing unit 7 during the rotation of the rotor 5, The rotation speed of the rotor 5 is monitored by the Hall sensors Ha, Hb and Hc which are initialized by the sensors 7 and 7. The rotation speed of the rotor 5 is shown in FIGS. 5 and 7 Likewise, after the drive command D has elapsed, it increases linearly over time during a period a.

In order to check whether or not an error signal is received from the Hall sensors Ha, Hb and Hc during the rotation of the rotor 5, the Hall sensors Ha, Hb and Hc are normally set to 0 2, at least one of the Hall sensors Ha, Hb, and Hc and the Hall sensors Ha, Hb, and Hc in the case of the three-phase driving unit in which the permanent magnets are disposed, It outputs two different signals. 4, the signals that can be output from the Hall sensors Ha, Hb and Hc are (0, 0, 1), (0, 1, 0) , 0,0), (1,0,1), (1,1,0), and when a signal corresponding to (0,0,0) or (1,1,1) is received, , Hb, Hc) are regarded as malfunctioning.

Next, the error checking step S30 is a step of checking whether or not an error signal has been received by the sensing unit 7. As shown in FIG. 3, in the upper sensor monitoring step S20, the sensing unit 7 An error signal such as (0, 0, 0) or (1, 1, 1) is received from the hall sensor (Ha, Hb, Hc) (S30). If the above error signal is not received, the controller 5 is controlled by using the sensing unit 7, that is, the Hall sensors Ha, Hb and Hc to drive the driving unit S31, 7). However, if the error signal has been received, the process proceeds to the next step S40 so as to drive the driving unit by controlling the rotor 5 by the sensorless method.

Next, the sensorless control step S40 is a step of switching the control mode to the sensorless mode when an error signal is detected by the sensing unit 7, and as shown in FIG. 3, S30 are received from the sensing unit 7 by the control unit 9 when an error signal such as (0,0,0) or (1,1,1) is received from the sensing unit 7 And the control system is switched to the sensorless system to control the rotor 5. At this time, the rotational speed of the rotor 5 increases linearly up to the peak value over the time interval b shown in FIG. 5 and FIG. 7, and then maintains a constant speed.

Meanwhile, the sensorless control algorithm according to the present invention uses, for example, a sliding mode observer (SMO) method, and the SMO including the switch function Zs is represented by the following equation (1).

Here, the switching function Zs is as shown in the following Equation 2, and the variable k included in this function is an important factor that affects the stability of the SMO algorithm and has a characteristic to be changed according to the magnitude of the counter electromotive force. Also, the magnitude of the counter electromotive force is changed according to the driving part variable and the rotational speed.

Next, the deceleration control step S50 is a step of decelerating the rotor 5 when an operation stop signal is received. The deceleration control step S50 includes a step S51 of confirming whether an operation stop signal has been received, And the actual deceleration control is performed (S52) when the operation stop signal is confirmed. In the sensorless control step S40, during the control of the rotor 5 according to the sensorless method, the controller 9 When the operation stop signal is received (S51), the rotor 5 is decelerated through the control unit 9 (S52). At this time, the rotation speed of the rotor 5 is changed to the stop command S), the peak value decreases linearly with time. However, if it is confirmed in the operation stop signal reception confirmation step S51 that the operation stop signal has not been received, the sensorless control S40 may be continued.

Next, the deceleration control step S50 is a step of decelerating the rotor 5 when the operation stoppage signal is received. The step S51 of confirming whether the operation stoppage signal has been received, as shown in FIG. 3, And the actual deceleration control is performed (S52) when the operation stop signal is confirmed. In the sensorless control step S40, during the control of the rotor 5 according to the sensorless method, the controller 9 When the operation stop signal is received (S51), the rotor 5 is decelerated through the control unit 9 (S52). At this time, the rotation speed of the rotor 5 is changed to the stop command S), the peak value decreases linearly with time. However, if it is confirmed in the operation stop signal reception confirmation step S51 that the operation stop signal has not been received, the sensorless control S40 may be continued.

Next, the rotor position estimating step S60 is a step of estimating a reference position of the rotor 5 to restart the sensorless control on the rotor 5, A step S61 of confirming the rotational speed of the electron 5 and a step S62 of estimating the reference position of the rotor 5 in the step S61, It is confirmed whether or not the rotational speed of the electron 5 is zero (Z) in Fig. As a result, if it is confirmed that the rotation speed does not reach 0, the deceleration control (S52) may be maintained. However, if it is determined in step S61 that the rotational speed has reached 0, the reference position of the rotor 5 is estimated in step S62 to find a synchronization point.

Next, the sensorless control resuming step S70 is a step of resuming the surge control on the rotor 5, and as shown in Fig. 3, in the upper rotor position estimating step S60, 5, the rotor 5 is operated as in the above sensorless control step S40 according to the next drive command D 'as shown in FIG. Thus, the rotor 5 increases linearly with time after the drive command D 'as shown.

6, the sensorless control method of a BLDC motor according to another embodiment of the present invention includes a sensor initialization step S110, a sensor monitoring step S120, an error checking step S130, A control step S140, a deceleration control step S150, a gain value estimation step S160, and a sensorless control resumption step S170.

In the sensor initializing step S110, the sensor monitoring step S120, the error checking step S130, the sensorless controlling step S140 and the deceleration controlling step S150 are respectively performed in the sensor initializing step S10 of the first embodiment, The sensor monitoring step S20, the error checking step S30, the sensorless controlling step S40, and the deceleration controlling step S50, the description thereof will be omitted.

The gain value estimating step S160 is a step of estimating a gain value of the variable k of the control algorithm according to the sensorless method when the operation signal is received again during deceleration according to the deceleration command, (S161) of confirming whether or not the operation signal of the rotor 5 is inputted again, and a step (S162) of estimating the gain value of the control algorithm variable k according to the sensorless method. Therefore, in the gain value estimation step S160, when the rotor 5 operation signal is received again during the deceleration of the rotor 5 in the deceleration control step S150 (S161) (K) gain value of the control algorithm according to the sensorless method by the control unit 9 through a normal signal other than the error signal that is generated by the sensorless method (S162). However, if the operation signal is not received again in the step S161, the rotation speed is continuously decreased until the rotation speed becomes 0. When the rotation speed becomes 0 in this manner (S163), a separate control algorithm The sensorless control S140 may be performed as in the first embodiment without needing to estimate the gain value of the variable k.

Next, the sensorless control resumption step S170 resumes the control of the rotor 5 in a sensorless manner. As shown in FIG. 6, the sensorless control step resumes the control of the variable 5 the control unit 9 restarts the control of the rotor 5 in the sensorless manner of the sensorless control step (S140) described above in accordance with the gain value. At this time, the rotational speed of the rotor 5 increases linearly again up to the peak value after a re-start (R) command as indicated by the section (d) of FIG.

The sensorless control method for the rotor 5 of the electric BLDC motor 1 thus terminated is terminated when the driving of the BLDC motor 1 is turned off and when the driving of the BLDC motor 1 is continued, (Step S151).

1: BLDC motor 3: stator
5: rotor 7: sensing unit
9: control part 25: stator core
27: permanent magnet 31: housing
33: coil 37: rotating shaft

Claims (2)

delete A stator 3 in which a coil 33 is wound inside a stator core 25 fixed in a housing 31 constituting an outer body,
A rotor 5 including a permanent magnet 27 mounted coaxially and rotatably inside the stator 3,
A sensing unit 7 disposed on the inner circumferential surface of the stator 3 at regular intervals in the circumferential direction to sense the rotation of the rotor 5,
And a control unit 9 for controlling the rotation operation of the rotor 5 according to the rotation information of the rotor 5 transmitted from the sensing unit 7. In the driving control method for the BLDC motor 1, As a result,
A sensor initializing step S110 for initializing the sensing unit 7 according to the start of driving of the BLDC motor S111;
A sensor monitoring step (S120) of monitoring the rotation of the rotor (5) by the sensing unit (7) initialized in the sensor initializing step (S110);
An error checking step (S130) of checking the error signal received from the sensing part (7) during the monitoring of the rotor (5) by the sensing part (7) );
If the reception of the error signal from the sensing unit 7 is confirmed in the error checking step S130, the control unit 9 ignores the signal received from the sensing unit 7, A sensorless control step (S140) of controlling the electron (5);
If the operation stop signal is received by the control unit 9 in step S151 while the rotor 5 is being controlled according to the sensorless method in the sensorless control step S140, A deceleration control step (S150) of decelerating the accelerator 5 (S152);
If the operation signal of the rotor 5 is received during the deceleration of the rotor 5 in the deceleration control step S150 in step S161, a normal signal other than the error signal received from the sensing unit 7 A gain value estimating step (S160) of estimating a gain value of a variable (k) of the control algorithm according to the sensorless method by the control unit (9) (S162); And
(K), which is a factor affecting the stability of the sensorless control algorithm, based on the variable (k) gain value estimated in the gain value estimation step (S160) (S170) restarting the control of the rotor (5) by the sensorless control of the sensorless control step (S140) by the control unit (9);
And the sensorless control method of the driving unit of the BLDC motor.

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