JP2011217584A - Motor drive unit and method of controlling the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor drive unit and a method of controlling the motor drive unit, which facilitate correction of relative error in each sensor detecting a magnetic pole position of a rotor and adjustment of an advance angle, and enable a motor to be driven with high efficiency.SOLUTION: A motor drive unit 1 is equipped with: an inverter section 12 that supplies motor current flowing to a multiple phase coil; a current detecting section 11 that detest the motor current; and a control section 3 that supplies a control signal for operating the inverter section 12 with a predetermined excitation pattern. The control section 3 is equipped with a tuning section 7 into which both positional information from a plurality of magnetic pole position sensors 13 to 15 attached to a motor 16 and current information from the current detecting section 11 are inputted. The tuning section 7 is equipped with: a relative error correction means for correcting relative errors in the positional information; and an advance angle adjustment means for adjusting the advance angle of the motor, based on the positional information of which the relative errors have been corrected and the current information.

Description

  The present invention relates to a motor drive device and a control method thereof, and more particularly, to a motor drive device and a control method thereof for driving a motor including a stator made of a multiphase coil and a rotor made of a permanent magnet with high efficiency.

In general, a motor (for example, a brushless DC motor; hereinafter, also simply referred to as a motor) having a stator made of a multiphase coil and a rotor made of a permanent magnet switches an inverter provided in the motor drive device with a predetermined excitation pattern. Thus, the motor current flowing through the multi-phase (for example, three-phase) coil is sequentially supplied to generate a rotating magnetic field, and the rotor made of a permanent magnet is configured to rotate following the rotating magnetic field.
In order to drive such a motor, a means for detecting or estimating the magnetic pole position is necessary to supply an appropriate motor current corresponding to the magnetic pole position of the rotor. For example, the magnetic pole position is determined using a plurality of Hall sensors. It is done to detect.

Here, in the driving of the motor, if there is a detection error in the magnetic pole position, the timing for exciting the inverter shifts and the efficiency deteriorates. As a cause of such detection error, there is an assembly error of each hall sensor to the motor shaft, and this assembly error is a problem because the error angle tends to increase particularly when a motor having a large diameter is driven. Become.
One means for solving this problem is to detect the magnetic pole position using a high-precision angle sensor such as a resolver, for example. However, such a high-precision angle sensor is expensive and is driven by a motor. There is a problem that the cost of the apparatus increases.
Thus, conventionally, a method for correcting the relative error of the magnetic pole position detection information from each Hall sensor has been proposed (see, for example, Patent Document 1).

JP 2007-166735 A

  However, the motor drive control not only corrects the relative error of the mounting position of each Hall sensor, but in order to maximize the torque especially by the sinusoidal drive, the induced voltage and motor current of the motor coil The so-called advance angle adjustment for adjusting the phase is also important, and Patent Document 1 described above does not disclose such advance angle adjustment.

  The present invention has been made in view of the above problems, and it is possible to easily perform correction of relative error and adjustment of advance angle of each sensor for detecting the magnetic pole position of the rotor, and drive the motor with high efficiency. An object of the present invention is to provide a motor driving device and a control method thereof.

  The following aspects of the present invention exemplify the configuration of the present invention, and will be described separately for easy understanding of various configurations of the present invention. Each section does not limit the technical scope of the present invention, and some of the components of each section are replaced, deleted, or further, while referring to the best mode for carrying out the invention. Those to which the above components are added can also be included in the technical scope of the present invention.

(1) In a motor drive device for driving a motor including a rotor having a permanent magnet and a stator having a multiphase coil,
An inverter unit for supplying a motor current flowing through the multiphase coil, a current detection unit for detecting the motor current, and a control unit for supplying a control signal for operating the inverter unit with a predetermined excitation pattern,
The control unit includes a tuning unit that receives position information from a plurality of magnetic pole position sensors attached to the motor and current information from the current detection unit, and the tuning unit includes a relative error of the position information. A motor drive device comprising: a relative error correction unit that corrects the angle; and an advance angle adjustment unit that adjusts the advance angle of the motor based on the position information and the current information after the relative error correction. 1).

(2) In the motor drive device described in (1), the control unit calculates a rotation speed of the rotor based on the position information after the relative error correction input from the tuning unit. A phase calculation unit that calculates the phase of the motor based on the rotational speed input from the speed calculation unit and the positional information after the relative error correction input from the tuning unit, the rotational speed and the target speed, And a vector calculation unit that forms a control signal for operating the inverter unit based on the error of the motor, the phase of the motor, and the current information.

(3) In the motor driving device according to (1) or (2), the relative error correction unit measures a time difference between input signals from the magnetic pole position sensors, takes an average of these, and Relative error of the position information is corrected by obtaining an error from the average and correcting the corresponding electrical angle for each of the other magnetic pole position sensors based on the input signal of one of the magnetic pole position sensors. A motor driving device (claim 3).

(4) In the motor drive device according to any one of (1) to (3), the advance angle adjusting means includes a phase of the motor and a motor current obtained from the position information after the relative error correction. The motor drive apparatus is characterized in that the advance angle is adjusted by searching for the phase at which the motor current is minimized based on the correlation of the motor current.

(5) An inverter unit that supplies a motor current flowing through the multiphase coil, a current detection unit that detects the motor current, and a control unit that supplies a control signal for operating the inverter unit with a predetermined excitation pattern, A method of controlling a motor driving apparatus for driving a motor including a rotor having a permanent magnet and a stator having a multiphase coil, wherein relative position information from a plurality of magnetic pole position sensors attached to the motor A control method comprising: correcting an error; and adjusting an advance angle of the motor based on the position information and the current information after correcting the relative error (Claim 5).

  Since the load driving device according to the present invention is configured as described above, a highly accurate angle sensor is used by easily correcting the relative error and adjusting the advance angle of each sensor that detects the magnetic pole position of the rotor. Therefore, it is possible to provide a motor driving device and a control method thereof that can drive a motor with high efficiency.

It is a block diagram which shows the motor control system containing the motor drive device in one Embodiment of this invention. 2 is a flowchart illustrating an example of an operation of a tuning unit in the motor drive device illustrated in FIG. 1. In one Embodiment of this invention, it is a figure which shows the example of the signal from a Hall sensor, (a) is a figure which shows the case where there is no relative error, (b) shows the case where there is a relative error. 5 is a flowchart illustrating an example of an advance angle adjustment processing operation in an embodiment of the present invention. 6 is a flowchart illustrating another example of the operation of the tuning unit in the motor drive device according to the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a block diagram showing a motor control system 10 including a motor drive device 1 according to an embodiment of the present invention. The motor control system 10 includes a motor driving device 1 and a motor unit 2. The motor unit 2 includes a motor 16 that is a permanent magnet type brushless DC motor, and three hall sensors 13 and 14 attached to the motor 16. Consist of 15. In the present embodiment, the motor 16 is, for example, a permanent magnet type brushless DC motor, and includes a rotor having a two-pole permanent magnet and a stator including a three-phase coil. The three Hall sensors 13, 14, 15 function as magnetic pole position sensors that detect the magnetic pole position of the rotor of the motor 16.

In the motor control system 10, the motor driving device 1 includes an inverter unit 12 including a three-phase bridge circuit 17 and a three-phase bridge driver 9 that drives the circuit, and a current detection unit that detects a motor current flowing in a three-phase coil of the motor 16. 11 and a control unit 3 for supplying a control signal for operating the inverter unit 12 to the inverter unit 12.
Further, the control unit 3 includes a tuning unit 7, a storage unit 8, a speed calculation unit 4, a phase calculation unit 5, and a vector calculation unit 6, and positional information and current input from the Hall sensors 13, 14, and 15. Based on the current information input from the detection unit 11 and the target speed, a PWM control signal for operating the inverter unit 12 with an appropriate excitation pattern to rotate the motor 16 at the target speed is formed. This is output to the three-phase bridge driver 9 of the unit 12.

  Here, in the motor drive device 1 of the present embodiment, the control unit 3 includes a tuning unit 7, and the tuning unit 7 is a relative error correction unit for position information input from the Hall sensors 13, 14, and 15. And an advance angle adjusting means for adjusting the advance angle of the motor 16 based on the position information after the relative error correction and the current information from the current detection unit 11. Next, the operation of the tuning unit 7 will be described in detail.

  In the present embodiment, at least the control unit 3 is preferably configured as a microcontroller system including necessary volatile memory (RAM) and non-volatile memory (ROM). The advance angle adjusting means is implemented as a software module that executes the operations described below. However, the present invention is not limited by the mounting mode of these components, and the control unit 3 (and its relative error correction unit and advance angle adjustment unit) is arbitrary as long as the control operation described later is executed. It may be realized by appropriate hardware or software, or a combination thereof.

  FIG. 2 is a flowchart showing an outline of the operation in the tuning unit 7. The tuning unit 7 starts the tuning operation at any appropriate timing, and first executes the relative error correction processing of each Hall sensor 13, 14, 15 (step S101), and if the relative error correction processing is completed. (Yes in step S102), an advance adjustment process of the control phase of the motor 16 is executed (step S103). When the control phase advance angle adjustment process ends (Yes in step S104), the tuning operation ends.

  Here, the tuning operation in the tuning unit 7 is executed once, for example, when the motor control system 10 is shipped from the factory, and a correction value for relative error and an adjustment value for advance angle, which are obtained as described later, are stored in the storage unit 8. Thereafter, the control unit 3 may form a control signal based on the correction value and the adjustment value. Alternatively, the tuning operation in the tuning unit 7 may be started each time the target speed (rotational speed command) changes to a predetermined reference or more to update the correction value and the adjustment value. The latter method is advantageous in correcting the relative error and adjusting the advance value with high accuracy. On the other hand, when the motor control system 10 is used in an application in which the target speed is frequently changed. In some cases, the former method is advantageous for smooth driving of the motor 16.

Here, with reference to FIG. 3, the relative error correction processing of the hall sensors 13, 14, and 15 will be specifically described as follows. In the present embodiment, the hall sensors 13, 14, and 15 are arranged around the axis of the motor 16 so as to be spatially separated from each other by 120 degrees. Signals input to the tuning unit 7 from the sensors 13, 14, and 15 are as shown in FIG.
The signals of the hall sensors 13, 14, and 15 (corresponding to the signals HallA, HallB, and HallC shown in FIG. 3) are high at every electrical angle of 180 ° according to the rotational position of the rotor of the motor 16, respectively. The rotation position of the rotor having an electrical angle of 60 degrees is determined from the deviation (time difference) between the three signals HallA, HallB, and HallC.
When there is no relative error in the mounting position of each Hall sensor 13, 14, 15 as shown in FIG. 3A, for example, a time difference (HallA of Hall A) corresponding to an electrical angle of 60 degrees between the signals is obtained. The time T _AB from the high input to the high input of HallB, the time T _BC from the high input of HallB to the high input of HallC, and the time T _CA from the high input of HallC to the low input of HallA) are all equal ( T _AB = T _BC = T _CA ).

However, when there is a relative error in the mounting position of each Hall sensor 13, 14, 15, as shown in FIG. 3B, these time differences (time T _AB , time T _BC , time T _CA ) are It will be different. In this case, for example, HallA is selected as a reference, and the angle correction value for HallB (T _AB ) is calculated as follows by taking the average of time T _AB , time T _BC , and time T _CA as follows: it can.
The angle correction value for [(T _AB − (T _AB + T _BC + T _CA ) / 3) / (T _AB + T _BC + T _CA )] × 180 degrees HallC (T _CA ) is calculated in the same manner.
Note that T _AB + T _BC + T _CA is the time required for rotation of an electrical angle of 180 degrees.

The correction value calculated in this way is stored in the storage unit 8, and thereafter, the tuning unit 7 positions the speed calculation unit 4 and the phase calculation unit 5 where the relative error is corrected based on the correction value. Information is output.
Then, the speed calculation unit 4 calculates the rotational speed of the rotor based on the position information after the relative error correction, and the phase calculation unit 5 is based on the rotational speed information input from the speed calculation unit 4. Then, the current phase of the motor 16 is calculated finely by interpolating the position information after the relative error correction, and the vector calculation unit 6 calculates the rotation speed calculated by the speed calculation unit 4 and the given target speed. Based on the error, the phase of the motor 16 calculated by the phase calculation unit 5, and the current information from the current detection unit 11, a well-known vector calculation is performed to form a control signal for operating the inverter unit 12.
Thereby, the motor drive device 1 in the present embodiment can drive the motor 16 with high efficiency.

Next, the advance angle adjustment processing operation in the tuning unit 7 will be described with reference to FIG. In this advance angle adjustment processing operation, the phase at which the motor current is minimized is searched based on the correlation between the phase of the motor 16 obtained from the position information after the relative error correction and the motor current detected by the current detection unit 11. Thus, the advance value of the control phase is adjusted. Hereinafter, the advance angle adjustment processing operation will be described for each step shown in FIG.
In each step shown in FIG. 4, the motor control phase is obtained based on position information after the relative error is corrected by the correction value described above.

First, a phase adjustment value is initialized (step S201), and a phase adjustment step (step S202) (for example, about 0.05 degrees) is set. Next, the moving average of the motor current over a fixed time is calculated and stored from the current information of the current detector 11 (step S203), and the phase adjustment value is decreased by the phase adjustment step (step S204). Next, the phase adjustment direction is set to a decreasing (minus) direction (step S205).
Next, it waits for a certain period of time until the operation of the motor control system 10 is stabilized (steps S206 and S207), and then the current detection unit 11 present (that is, after the phase adjustment value is decreased by the phase adjustment step) ) From the current information, the moving average of the motor current for a fixed time is calculated (step S208). Next, the current moving average calculated in step S208 is compared with the previous moving average stored in step 203 (step S209), and the current moving average is smaller than the previous moving average (step S210). Yes), the control shifts to step S211.

If the determination in step 210 is YES, it means that the motor current has decreased (that is, the efficiency has improved) by decreasing the phase adjustment value, so the moving average value of the motor current is the current value. (Step S211), the phase adjustment value is changed, and the search for the phase adjustment value is repeated again from step S206.
However, at this time, in step S212, it is determined whether or not the adjustment direction is a decrease (minus) direction. If the adjustment direction is the decrease direction (Yes), the phase adjustment value is decreased by the phase adjustment step (step S213). If it is in the increasing direction (No), the phase adjustment value is increased by the phase adjustment step (step S214).

  On the other hand, when the current moving average is equal to or higher than the previous moving average in step S210 (No in step S210), the control proceeds to step S215, and it is determined whether or not the determination in step S210 is the first time. (Step S215). If the result of this determination is Yes, the phase adjustment value adjustment direction is set to an increasing (plus) direction (step S216), and the process proceeds to step S211. As a result, the range in which there is a possibility that the phase adjustment value at which the motor current is minimized exists again in the reverse direction. Here, a value smaller than the initial value may be set as the phase adjustment step.

  If the result of determination in step S215 is No, the phase adjustment value is returned to the previous value (that is, if the adjustment direction is decreasing in step S217 (Yes), the phase adjustment value is set to the phase adjustment step. If the adjustment direction is the increase direction (No), the phase adjustment value is decreased by the phase adjustment step (step S219). Next, the motor current is minimized by this phase adjustment value. Therefore, the adjustment value having the maximum efficiency is stored in the storage unit 8 (step S220), and the control phase advance angle adjustment processing ends.

  The angle adjusted by this advance angle adjustment process is an optimum advance angle adjustment value at the rotational speed set during the tuning operation in the tuning unit 7. Although the optimum amount of advance of the motor varies depending on the motor speed and load, for example, in a motor used for a fan such as an air conditioner, the magnitude of the load is determined by the characteristics of the fan rotated by the motor. It is known that the optimal advance amount is proportional to the rotation speed, and can be expressed by an appropriate linear function. Therefore, the adjustment value for the entire rotation region of the motor can be obtained from the adjustment value obtained by the advance angle adjustment processing shown in FIG.

  As described above, the motor drive device 1 according to the present embodiment performs both the correction of the relative error and the advance angle adjustment of the Hall sensors 13, 14, and 15 that detect the magnetic pole position of the rotor in the tuning unit 7. In the motor control system 10, the motor 16 can be driven with high efficiency.

Further, in the present embodiment, a vector control method (180-degree energization method) in which an in-phase sine wave current is applied to an induced voltage that changes in accordance with the rotational position of the rotor, or an advanced phase sine wave current is applied. However, the motor driving device and the control method thereof according to the present invention select the winding with the maximum phase and the minimum phase with respect to the induced voltage that changes according to the rotational position. Thus, the present invention is also applicable to a method of energizing (120-degree energization method).
As shown in FIG. 5, in the modification example of the phase adjustment operation, first, the phase adjustment process using the adjustment target phase as the hall sensor A (13) is executed (steps S301 and S302). The phase adjustment process with the hall sensor B (14) is executed (steps S304 and S305), and after that, the phase adjustment process with the phase to be adjusted as the hall sensor C (15) is executed (steps S307 and S308), Finally, the phase to be adjusted may be set to advance angle adjustment (step S310), and the phase adjustment process may be executed (step S311).
Even in this case, the specific operation of each phase adjustment process (steps S302, S305, S308, and S310) is the same as the phase adjustment process shown in FIG.
Further, the phase adjustment method is not limited to the method shown in FIG. 4, and may be a method of controlling the phase adjustment step using a binary search method, for example. By using the two-minute search method, it may be possible to shorten the adjustment time or perform an accurate adjustment.

1: motor drive unit, 2: motor unit, 3: control unit, 4: speed calculation unit, 5: phase calculation unit, 6: vector calculation unit, 7: tuning unit, 8: storage unit, 9: three-phase bridge driver DESCRIPTION OF SYMBOLS 10: Motor control system, 11: Current detection part, 12: Inverter part, 13, 14, 15: Hall sensor (magnetic pole position sensor), 16: Motor, 17: Three-phase bridge circuit

Claims (5)

In a motor driving device for driving a motor including a rotor having a permanent magnet and a stator having a multiphase coil,
An inverter unit for supplying a motor current flowing through the multiphase coil, a current detection unit for detecting the motor current, and a control unit for supplying a control signal for operating the inverter unit with a predetermined excitation pattern,
The control unit includes a tuning unit that receives position information from a plurality of magnetic pole position sensors attached to the motor and current information from the current detection unit, and the tuning unit includes a relative error of the position information. A motor drive device comprising: a relative error correction unit that corrects the angle; and an advance angle adjustment unit that adjusts the advance angle of the motor based on the position information and the current information after the relative error correction. The control unit is configured to calculate a rotational speed of the rotor based on the positional information after the relative error correction input from the tuning unit, the rotational speed input from the speed calculation unit, and the tuning. A phase calculation unit that calculates the phase of the motor based on the positional information after the relative error correction input from the unit, an error between the rotational speed and the target speed, the phase of the motor, and the current information The motor driving apparatus according to claim 1, further comprising a vector calculation unit that forms a control signal for operating the inverter unit. The relative error correction means measures a time difference between signals input from the magnetic pole position sensors, takes an average of these, and obtains an error from the average for each of the other magnetic pole position sensors. The motor driving apparatus according to claim 1, wherein a relative error of the position information is corrected by correcting an electrical angle. The advance angle adjusting means searches for the phase at which the motor current is minimized based on a correlation between the motor phase and the motor current obtained from the position information after the relative error correction. The motor drive device according to any one of claims 1 to 3, wherein the angle is adjusted. An inverter unit for supplying a motor current flowing in the multiphase coil, a current detection unit for detecting the motor current, and a control unit for supplying a control signal for operating the inverter unit with a predetermined excitation pattern, A method for controlling a motor driving device for driving a motor including a rotor having a stator and a stator having the multiphase coil,
Correcting a relative error of position information from a plurality of magnetic pole position sensors attached to the motor; adjusting an advance angle of the motor based on the position information and the current information after correcting the relative error; The control method characterized by including.

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