JP4660688B2 - Method and controller for estimating initial magnetic pole position of sensorless salient pole type brushless DC motor - Google Patents

Description

  The present invention relates to a magnetic pole position estimation method and apparatus for a sensorless salient pole type brushless DC motor having no magnetic pole sensor and position sensor.

  As background art, the magnetic pole position estimation method of the permanent magnet type brushless motor described in patent document 1 is illustrated. FIG. 6 is a conceptual block diagram of this method. In this method, a virtual rotation coordinate (γ-δ) axis is introduced, and the sign of the product of the γ-axis current command value and the integral value of the δ-axis error current is used. The virtual γ-axis is moved clockwise or counterclockwise by Δθ to bring the estimated position angle θγ closer to the actual magnetic pole axis d-axis. The integral value of the δ-axis error current decreases when the actual magnetic pole axis d-axis and the estimated magnetic pole axis γ-axis coincide with each other. This process is performed twice. If the difference in θγ does not fall within 20 degrees, the position angle is estimated again.

JP 2006-109651 A

However, the conventional magnetic pole position estimation method has the following problems.
(1) When the difference between the actual magnetic pole axis d-axis and the virtual magnetic pole axis γ-axis is reduced by introducing virtual rotational coordinates, the integrated value of the δ-axis current error is small, and noise and offset at the time of current detection are reduced. Since it is influenced and the sign of the integral value is used, it is difficult to determine near zero.
(2) The accuracy of the position angle estimation is lowered by introducing the sign of the integral value performed to eliminate the influence of the motor parameter fluctuation.

In order to solve the above problems, the initial magnetic pole position estimation method of the sensorless salient pole type brushless DC motor of the present invention includes:
A control stage for giving a sensorless salient pole type brushless DC motor driving device as an α-axis voltage command value and a β-axis voltage command value on αβ coordinates forming a stationary orthogonal coordinate system;
A current detection step of detecting an alternating current supplied from the driving device to the motor as an α-axis current and a β-axis current on the αβ coordinate;
A current amplitude deviation calculating step of calculating a current amplitude deviation between the amplitude of the α-axis current and the amplitude of the β-axis current,
In the control step, along with providing a high frequency voltage indicated the α-axis voltage command value and the β-axis voltage command value by the formula (1), it is greater than β-axis current towards the α-axis current, to v _sd V _td is relatively increased, and when the α-axis current is larger than the β-axis current, feedback control is performed so as to eliminate the current amplitude deviation by increasing v _sd relative to v _td . When the current amplitude deviation disappears, the initial magnetic pole position angle is calculated based on Expression (2) using v _td and v _sd at that time.

Here, the angular frequency ω _h is not particularly limited, but it is preferable that the driving device can output a sine wave and has a frequency as high as possible (for example, about the maximum rotation speed of the motor). Further, the amplitudes of the α-axis voltage command value v _α and the β-axis voltage command value v _β are not particularly limited as long as no torque is applied so that the motor rotates. The value is set to about 10% or less of the phase voltage. Then, based on the amplitudes of the α-axis voltage command value v _α and the β-axis voltage command value v _β , the amplitude of the AC current i _h for position angle estimation and the position angle estimation voltages v _sd and v _td Set.

  According to this method, as shown in the equation (2), the initial magnetic pole position angle can be calculated only with parameters given as control commands without including any motor parameters. This motor parameter refers to the motor's electrical parameters, and refers to the resistance value of the motor winding that changes due to temperature changes, and the fluctuation value of the motor winding resistance value and inductance caused by individual differences even with the same motor. Yes. Therefore, according to this method, in principle, the initial magnetic pole position angle can be accurately estimated without being affected by the fluctuation of the motor parameter, and thus, generation of high torque can be realized from the time of starting the motor. .

The control device for the sensorless salient pole type brushless DC motor of the present invention is
Control means for giving a sensorless salient pole brushless DC motor drive device as an α-axis voltage command value and a β-axis voltage command value on αβ coordinates forming a stationary orthogonal coordinate system;
Current detection means for detecting an alternating current supplied from the driving device to the motor as an α-axis current and a β-axis current on the αβ coordinate;
A current amplitude deviation calculating means for calculating a current amplitude deviation between the amplitude of the α-axis current and the amplitude of the β-axis current;
The control means gives the α-axis voltage command value and the β-axis voltage command value as a high-frequency voltage expressed by the formula (1), and when the α-axis current is larger than the β-axis current, it is set to v _sd . relatively increasing v _td against, alpha case towards the axis current is greater than β-axis current, v by relatively increasing the v _sd relative _td, feedback to eliminate the current amplitude deviation When the current amplitude deviation is controlled, the initial magnetic pole position angle is calculated based on the equation (2) using v _td and v _sd at that time.

  Also with this control device, the same effect as the initial magnetic pole position angle estimation method can be obtained.

  According to the initial magnetic pole position estimation method and the control device of the sensorless salient pole type brushless DC motor according to the present invention, in principle, the initial magnetic pole position angle can be accurately estimated without being affected by the fluctuation of the motor parameter. This produces an excellent effect that high torque can be generated from the start of the motor.

1 to 5 show an initial magnetic pole position estimation method and a control device 1 of a sensorless salient pole type brushless DC motor 10 (hereinafter referred to as a motor 10) according to an embodiment of the present invention. As shown in FIG. 1, the control device 1 gives the drive device 11 of the motor 10 as an α-axis voltage command value v _α and a β-axis voltage command value v _β on the αβ coordinate forming the stationary orthogonal coordinate system. The control means 2, the current detection means 3 for detecting the alternating current supplied from the driving device 11 to the motor 10 as the α-axis current i _α and β-axis current i _β on the αβ coordinate, and the α-axis current i _α Current amplitude deviation calculating means 4 for calculating a current amplitude deviation Δi between the amplitude of the current and the amplitude of the β-axis current i _β . The motor 10 is driven by a plurality of phases of alternating current. In this example, a motor driven by a three-phase (U, V, W) alternating current is used. FIG. 2 shows the relationship between the rotor position of the three-phase motor 10 and the αβ coordinate axis of the stationary coordinate system and the dq coordinate axis of the rotary coordinate system. The driving device 11 is a PWM inverter that converts DC power into three-phase AC power of an arbitrary frequency. The DC power supplied to the driving device 11 is the three-phase AC power of the three-phase power source 12 is a three-phase power source rectifier. 13 is rectified. A DC voltage smoothing capacitor 14 is connected between the output terminals of the three-phase power supply rectifier 13.

Current detection means 3, an alternating current i _u supplied to the U phase and V phase of the motor _10, to detect the i _v, which to convert the alpha-axis current i _alpha and beta axis current i _beta on αβ coordinates It is configured.

Current amplitude deviation calculation means 4, alpha amplitude value of the axis current i _α | i _α | _max and the amplitude value of the beta-axis current i _β | i _β | using the _max, the current amplitude deviation Δi = | i _α | _max − | I _β | _max is output.

The control means 2 includes a voltage command unit 8 that gives an α-axis voltage command value v _α and a β-axis voltage command value v _β by a high-frequency voltage expressed by the equation (1), and an α-axis current i _α is a β-axis current i. _When larger than _β (Δi> 0), v _td is relatively increased with respect to v _sd , and when α-axis current i _α is larger than β-axis current i _β (Δi <0), v _td V _sd control unit 6 and v _td control unit 7 for relatively increasing v _sd with respect to the voltage command unit 8, v _sd control unit 6 and v _td control unit 7, the current amplitude deviation Δi is set. It is configured to perform feedback control so as to eliminate. In this example, as a method of increasing / decreasing v _td and v _{sd in} the v _sd control unit 6 and the v _td control unit 7, a vector <v _d > = [v _sd , v _td ] = v _d e consisting of v _td and v _sd. ^By defining ^jθd , | v _d | = √ (v _sd ² + v _td ² ) is limited to a certain value or less so that the voltage does not increase, and α-axis current i _α is β-axis current i. _When larger than _β (Δi> 0), v _td is increased relative to v _sd by increasing θd, and α-axis current i _α is larger than β-axis current i _β (Δi < 0) employs a method of increasing v _sd relative to v _td by decreasing θd.

Further, when the current amplitude deviation Δi disappears, the control unit 2 includes a position angle calculation unit 5 that calculates the initial magnetic pole position angle θ based on the equation (2) using v _td and v _sd at that time. As a method for determining whether n in the formula (2) is 1 (N pole) or 3 (S pole), a known determination method can be appropriately employed. As this discrimination method, in this example, when the power supply voltage V _dc is increased, the magnitude of the increase in the positive half-wave amplitude i _αPmax and the negative half-wave amplitude i _αNmax of i _α (or i _β ) is compared. Te, increment is large when the n = 1 (n pole side) of the i _ArufaPmax, when the increment of i _ArufaNmax large employs a method of determining n = 3 and (S pole side).

  Next, a method for deriving equation (2) will be described. First, the voltage / current equation of the stationary coordinate system is expressed by Equation (3).

Comparing Expression (1) and Expression (3), Expression (4) is obtained when the current amplitude deviation Δi is 0, that is, | i _α | _max = | i _β | _max .

  When formula (4) is multiplied by a rotation matrix and arranged, formula (5) is obtained, and formula (2) is derived from this formula.

Next, control processing of the control device 1 of the present invention will be described with reference to a flowchart shown in FIG. 3 together with an initial magnetic pole position estimation method performed using the same device. First, as an initial setting in the voltage command unit 8 of the control means 2, the voltage v _dc of the DC voltage smoothing capacitor 14 is detected, and the α-axis voltage command value v _α and the β-axis voltage command value v are based on this voltage v _{dc. In addition} to determining the amplitude of _β , the AC current i _h for position angle estimation and the voltage amplitude v _d for position estimation are determined based on this, and further, for example, 45 degrees is set as the initial value of θd (step S50). . Next, the voltage command unit 8 of the control means 2 calculates the voltage command values v _α and v _β by the high frequency shown in the equation (1), and outputs them to the drive device 11 (step S51). Next, the current detection means 3 detects the α-axis current i _α and the β-axis current i _β (step S52). Next, the current amplitude deviation Δi is calculated by the current amplitude deviation calculating means 4 using the α-axis current i _α and the β-axis current i _β (step S53). Then, the v _sd controller 6 and v _td controller 7, respectively to check the current amplitude deviation .DELTA.i, larger than the current amplitude deviation .DELTA.i is 0 (step S54, S55), to v _sd by increasing θd V _td is relatively increased (step S56), and the process returns to step S51. If the current amplitude deviation Δi is smaller than 0 (steps S54 and S55), v _sd is made relative to v _td by decreasing θd. (Step S57) and return to step S51. Further, the current angle deviation Δi is checked by the position angle calculation means 5, and when Δi is 0 (step S54), v _td and v _sd when the current amplitude deviation Δi is lost are used, By discriminating whether n is 1 (N pole) or 3 (S pole) by the discrimination method, the initial magnetic pole position angle θ is calculated based on the formula (2), and this processing is terminated.

Thus, the present initial magnetic pole position estimation method, the control step of providing a relative drive 11 of the motor 10, alpha-axis voltage command value on the αβ coordinates forming the stationary rectangular coordinate system v _alpha and beta-axis voltage value v _beta (Steps S51, S54 to S58), and a current detection step of detecting the alternating current supplied from the driving device 11 to the motor 10 as the α-axis current i _α and β-axis current i _β on the αβ coordinate (Step S52). ) And a current amplitude deviation calculating step (step S53) for calculating a current amplitude deviation Δi between the amplitude of the α-axis current i _{α and} the amplitude of the β-axis current i _β . In the control step, the α-axis voltage command value v _α and the β-axis voltage command value v _β are given by the high-frequency voltage represented by the equation (1) (step S51), and the α-axis current i _α is the β-axis voltage. When it is larger than the current i _β (steps S54 and S55), v _td is relatively increased with respect to v _sd (step S56), and when the α-axis current i _α is larger than the β-axis current i _β (step S56). S54 and S55) increase the value of v _sd relative to v _td (step S57) to perform feedback control so as to eliminate the current amplitude deviation Δi, and when the current amplitude deviation Δi disappears (step S54), calculating the initial magnetic pole position angle θ based on v equation using _td and v _sd (2) at that time is (step S58) as.

  According to the control device 1 and the initial magnetic pole position estimation method of the present example configured as described above, as shown in the equation (2), the motor parameter is not included at all, and only the parameter given as the control command is the initial value. The magnetic pole position angle θ can be calculated. For this reason, in principle, the initial magnetic pole position angle θ can be accurately estimated without being affected by fluctuations in the motor parameters, whereby high torque can be generated from the start of the motor.

  The present invention is not limited to the above-described embodiment. For example, the present invention is applied to a motor having a plurality of phases other than three phases, and the invention is appropriately modified and embodied without departing from the spirit of the invention. You can also

The present embodiment shows an example in which the initial magnetic pole position angle θ is estimated for the motor 19 having a rated phase voltage of 200 [V]. The motor 19 has an armature winding resistance R = 3 [Ω], a d-axis inductance L _d = 0.012 [H] on the dq coordinate, and a q-axis inductance L _q = 0.018 [H]. And has the inductance characteristics shown in FIG. In this embodiment, the voltage v _dc = 28 [V] of the DC voltage smoothing capacitor 14, the voltage command value V (amplitude of v _α and v _β ) = 5 [V], the angular frequency of the alternating current for position angle estimation. ω _h = 200 [Hz], amplitude i _h = 0.1 [a] of the AC current, and the position estimation voltage amplitude v _d = 2 [V].

Here, the voltage v _dc = 28 [V] of the DC voltage smoothing capacitor 14 at the output portion of the three-phase power supply rectifier 13 is used for DC voltage smoothing when the power is turned on or when returning from the standby power reduction mode. the voltage v _dc is relatively low state of the capacitor 14 (28 [V]), as shown in FIG. 5, the output current i _alpha of the driving device 11, can be accurately controlled i _beta, further estimation accuracy of the magnetic pole position angle It is because it can raise. Further, the voltage command value V = 5 [V] is set so that the rated phase voltage 200 [V] of the motor 19 is not applied to the V so that the torque that rotates the motor 19 is not applied when the position angle is estimated according to the present invention. This is because it is desirable to set the value to about 10% or less of V]. The reason why the angular frequency ω _h = 200 [Hz] is that ω _h is preferably a sine wave that can be output by PWM control in the driving device 11 and is preferably as high as possible. The maximum rotation speed of the motor 19 is about 100 [Hz] to 300 [Hz]. Further, the current command value i _h = 0.1 [A] is determined from the inductance L _d (0.012 [H]) and L _q (0.018 [H]) of the motor 19 in the right side of the equation (1). Considering only the two terms, the maximum value of the current command value i _h is i _hm = V / {ω _h (L _d + L _q ) / 2} = 0.265 [A]. Since there are currents according to the first and third terms, the current command value i _h is set to a value less than this. Further, the position estimation voltage amplitude v _d = 2 [V] is set so that the amplitude of the current flowing with respect to the voltage command value V = 5 [V] is i _hm . The amplitude of the voltage due to the term L _d −L _q is i _hm × ω _h × (L _d −L _q ) / 2 = 1 [V], and v _d is the voltage command value V from this voltage 5 [ V] was set to a voltage equal to or lower than that.

The estimation results for this example are shown in Table 1. Thus, according to the present invention, the estimation accuracy of the initial magnetic pole position angle θ is about ± 3 degrees, and the initial magnetic pole position angle can be estimated with high accuracy.

1 is a conceptual block diagram of a sensorless salient pole brushless DC motor control device according to an embodiment of the present invention. It is a figure which shows the relationship between the rotor position of the three-phase motor illustrated as the motor, the (alpha) (beta) coordinate axis of a stationary coordinate system, and the dq coordinate axis of a rotation coordinate system. It is a flowchart which shows the flow of the control processing of the same control apparatus. It is a figure which shows the inductance characteristic of the motor used in the Example. It is a figure which shows the motor current supplied to the alpha phase of the motor in an Example, and a beta phase, (a) shows the motor current before control, (b) shows the motor current after control (state where current amplitude deviation deltai disappeared). ing. It is a conceptual block diagram of the conventional magnetic pole position estimation method.

Explanation of symbols

_DESCRIPTION OF _SYMBOLS 1 Control apparatus 2 Current detection means 3 Current amplitude deviation calculation means 4 Control means 5 Position angle calculation means 6 v _sd control part 7 v _td control part 8 Voltage command part 10 Motor 11 Drive apparatus 12 Three-phase power supply 13 Three-phase power supply rectifier 14 DC voltage smoothing capacitor

Claims (2)

A control stage for giving a sensorless salient pole type brushless DC motor driving device as an α-axis voltage command value and a β-axis voltage command value on αβ coordinates forming a stationary orthogonal coordinate system;
A current detection step of detecting an alternating current supplied from the driving device to the motor as an α-axis current and a β-axis current on the αβ coordinate;
A current amplitude deviation calculating step of calculating a current amplitude deviation between the amplitude of the α-axis current and the amplitude of the β-axis current,
In the control step, along with providing a high frequency voltage indicated the α-axis voltage command value and the β-axis voltage command value by the formula (1), it is greater than β-axis current towards the α-axis current, to v _sd V _td is relatively increased, and when the α-axis current is larger than the β-axis current, feedback control is performed so as to eliminate the current amplitude deviation by increasing v _sd relative to v _td . and, the current the amplitude deviation is eliminated, sensorless salient brushless DC motor initial magnetic pole position estimation method which is adapted to calculate the initial magnetic pole position angle on the basis of v equation using _td and v _sd (2) at that time .

Control means for giving a sensorless salient pole brushless DC motor drive device as an α-axis voltage command value and a β-axis voltage command value on αβ coordinates forming a stationary orthogonal coordinate system;
Current detection means for detecting an alternating current supplied from the driving device to the motor as an α-axis current and a β-axis current on the αβ coordinate;
A current amplitude deviation calculating means for calculating a current amplitude deviation between the amplitude of the α-axis current and the amplitude of the β-axis current;
The control means may provide a high-frequency voltage indicated the α-axis voltage command value and the β-axis voltage command value by the formula (1), it is greater than β-axis current towards the α-axis current, to v _sd Te v _td relatively increases, is greater than β-axis current towards the α-axis current, v by relatively increasing the v _sd relative _td, the current feedback control as to eliminate the amplitude deviation When the current amplitude deviation disappears, the control unit for the sensorless salient pole brushless DC motor configured to calculate the initial magnetic pole position angle based on the equation (2) using v _td and v _sd at that time.

Images