KR100484818B1 - Synchronized Reluctance Motor Controlling System without a Sensor - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensorless control system of a synchronous reluctance motor, wherein the sensorless control measures a magnetic flux of the motor and estimates the speed and rotation angle of the motor rotor for the sensorless control of the synchronous reluctance motor. Low speed region for observing the speed and the rotation angle of the rotor so that the operation is determined according to the block and the estimated speed of the motor to compensate the estimated speed and the estimated rotation angle of the sensorless control block at the time of starting the motor and low speed driving. And a mode switching control unit controlling a tracking loop unit and an operation of the low speed region tracking loop unit according to the estimated speed, and stabilizing a chattering phenomenon according to on / off of the low speed region tracking loop unit. When the control system switches to the low speed / high speed mode according to the low speed / high speed driving, a phenomenon such as chattering occurs. It is possible to provide a sensorless control system of a synchronous reluctance motor that can prevent the sensorless control performance deterioration of the low speed mode after switching to the high speed mode, so that it can exhibit stable performance even when the error between the two modes is estimated. It can be effective.

Description

Synchronized Reluctance Motor Controlling System without a Sensor}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensorless control system of a synchronous reluctance motor. In particular, in estimating the speed and the rotation angle of a rotor of a synchronous reluctance motor without a sensor, an estimated speed and estimated rotation occurring at the start of the motor and at a low speed drive The present invention relates to a sensorless control system of a synchronous reluctance motor that can prevent angle errors and stabilize a system.

The synchronous reluctance motor means a motor in which the rotor and the stator drive source are synchronized, and when the current flows into the stator, the rotor rotates to minimize the resistance formed in the rotor. In particular, in order to drive the synchronous reluctance motor as described above, the position of the rotor must be known at all times. Recently, the use of the control system of the synchronous reluctance motor that detects the position of the rotor without a sensor has been greatly increased.

That is, the sensorless control system of the synchronous reluctance motor that detects the position of the rotor without a sensor configures the synchronous reluctance motor by measuring a voltage, a current flowing into the motor, and a magnetic flux generated in the motor accordingly. The first method of grasping the speed and rotation angle (or position; hereinafter referred to as rotation angle) of the rotor is used. That is, the first method estimates the speed and the rotation angle of the motor by the magnetic flux measured by the magnetic flux meter.

However, when the motor is started or driven at a low speed, a problem occurs in estimating the voltage in the flux meter, and thus, the estimated speed and the estimated rotation angle have a significant difference from the actual speed and the rotation angle of the rotor.

Therefore, a second method of preventing the occurrence of the error by injecting an additional signal into the flux meter during motor start or low speed driving is used in parallel with the first method. However, whether or not the second method is used is determined according to the speed of the motor. The sensorless control system of the synchronous reluctance motor, which has been controlled using the first method, is changed according to the change of the motor speed. The use of the second approach results in a less stable system.

In other words, when the estimated speed reaches a constant speed after starting the motor, the system using the second method is suddenly switched to the first method and controlled while the motor is driven in the low speed region, thereby chattering. Unstable phenomena occur.

The present invention has been made to solve the above-mentioned problems of the prior art, the object of which is to control the synchronous reluctance motor without a sensor, the speed and rotation angle of the motor rotor when the synchronous reluctance motor is driven at low speed and high speed It is to provide a sensorless control system of a synchronous reluctance motor that can prevent chattering that can occur in the system so that it can be stably estimated or observed.

According to a feature of the sensorless control system of a synchronous reluctance motor according to the present invention for solving the above problems, the magnetic flux of the motor for measuring the sensorless control of the synchronous reluctance motor and accordingly the speed of the motor rotor A sensorless control block for estimating the rotation angle; Low-speed area tracking loop for observing the speed and the rotation angle of the rotor to determine whether the operation is determined according to the estimated speed of the motor to compensate the estimated speed and the estimated rotation angle of the sensorless control block at the time of starting the motor and low-speed driving Wealth; The on / off speed of the low speed area tracking loop part is controlled to control the operation of the low speed area tracking loop part according to the estimated speed and the on / off speed of the low speed area tracking loop part is stabilized. It consists of a mode switching control that changes as the motor speed decreases and increases.

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

In the sensorless control system of the synchronous reluctance motor according to the present invention, as shown in FIG. 1, the magnetic flux of the synchronous reluctance motor is estimated and observed, and the speed and the rotation angle of the motor rotor are estimated from the estimated flux and the observer flux. The sensorless control block 100 to be estimated, and whether or not the operation is determined according to the estimated speed of the motor to compensate for the estimated speed and the estimated rotation angle of the sensorless control block 100 at the time of starting the motor and the low speed drive. The low speed region tracking loop unit 200 for observing the speed and the rotation angle of the rotor, and the low speed region tracking loop unit to stabilize the chattering phenomenon according to on / off of the low speed region tracking loop unit 200. The mode switching control unit 300 controls whether or not the operation of the 200 according to the estimated speed.

Here, the sensorless control block 100, as shown, α of the fixed coordinate system of the motor from the α, β voltage (Vα, Vβ) and current (Iα, Iβ) of the fixed coordinate system input to the motor Observation flux on the β axis , ) And the estimated flux on the d and q axes of the rotating coordinate system ( , ) And the observer flux on the q axis ( ) And a magnetic flux measuring device 101 outputting the magnetic flux measuring device 101, and an observer magnetic flux output from the magnetic flux measuring device 101. , ) And estimated flux ( , Rotation angle of the motor rotor from , cos ) Is estimated by the rotation angle estimation unit 102 and the estimated rotation angle (sin) output from the rotation angle estimation unit 102 , cos Speed of the rotor from It is composed of a speed estimator 103 for estimating ().

In addition, the operation of the low speed region tracking loop unit 200 is determined according to the variable (X). Here, the variable (X) is the estimated speed of the motor ( And the estimated speed is low compared to the high speed. In addition, the low speed region tracking loop unit 200 operating when the estimated speed is low speed converges the observed rotation angle of the rotor to the actual rotation angle of the rotor so that the observed speed of the motor converges to the actual speed.

In addition, the mode switching controller 300 detects a change in the variable X and controls whether the low speed region tracking loop unit 200 operates accordingly. That is, when the estimated speed of the motor increases from low speed to high speed, the mode switching controller 300 is grounded to 'A' so that the low speed region tracking loop unit 200 operates, and then the first speed (950 to 1100 rpm). When the estimated speed of the motor reaches, ground to 'B' to turn off the low speed region tracking loop unit 200.

In addition, when the estimated speed of the motor decreases from a high speed to a low speed, the mode switching controller 300 is grounded to 'B' so that the motor is controlled only by the speed and rotation angle estimated by the sensorless control block 100. On the other hand, when the estimated speed reaches the second speed (800 ~ 950rpm) is grounded to 'A' to turn on the low-speed area tracking loop unit 200.

In addition, the low speed region tracking loop unit 200 has a proportional observation speed proportional to the position of the rotor from the magnetic flux measured by the magnetic flux measuring device 101. ) And a proportional observation speed output unit 210 for outputting the estimated speed output from the speed estimating unit 103. ), A reference signal combination unit 221 for combining the reference signal η with the sum of the rotation angle errors of the observed rotation angle and the estimated rotation angle of the rotor, and the proportional observation speed ( ) From the estimated speed combined with the reference signal Observing speed calculating unit 222 for calculating () and the observing speed calculated by the observing speed calculating unit 222 ( ) By integrating ) Is an integrator 223 and the observed rotation angle output from the integrator 223 ) And triangular function conversion unit for outputting to the magnetic flux measuring unit 101, and the observation rotation angle output from the trigonometric function conversion unit 224 ( ) And the estimated rotation angle of the rotor ( Rotation angle error calculation unit 225 for calculating a rotation angle error of (), a first gain unit 226 for multiplying the calculated rotation angle error by a first reference gain value 'h', and the first crab The negative rotation angle error multiplied by the first reference gain value in the receiver 226 and the estimated speed ( ) Is added to the summation unit 227 for outputting to the reference signal combination unit 221.

Here, the estimated speed ( ) And proportional observation speed ( ) And observation speed ( ) Is equal to the following Equation 3, the observation speed calculation unit 222 is a proportional observation speed (Equation 3) ) And estimated speed ( By summing the observation speed ( ) Is calculated.

= +

In addition, the rotation angle error is multiplied by the first reference gain value 'h' to the estimated speed ( The reason for the forward compensation is to improve the dynamics of the control system by stabilizing the transients in the superimposition region at low and high speeds.

The reference signal η combined by the reference signal combination unit 221 is obtained through Equation 4 below.

η = 0.8 + (1-X) * 0.2

However, X is a variable (X) in which the change is sensed by the mode switching controller 300.

In addition, the low speed region tracking loop unit 200 further includes a band pass filter 201 for band pass filtering the value output from the speed estimator to 800 kHz, and the synchronous reluctance motor according to the present invention. The sensorless control system of the configuration further comprises an axis conversion unit 301 for converting the value output from the trigonometric function conversion unit 224 to the magnetic flux measuring device 101.

Furthermore, the proportional observation speed output unit 210 of the low speed region tracking loop unit 200 may have an estimated magnetic flux on the q-axis output from the magnetic flux meter 101. ) And observer flux ( Flux error calculation unit 211 that calculates an error of the? Magnetic flux error proportional value of the motor rotor ) And a magnetic flux error proportional value obtained from the demodulator. ) Is multiplied by the second reference gain value ('40') ) Is a second gain unit 214 for outputting, and the position error proportional value () output from the second gain unit 214 ( ) Is a low pass filter 215 for low pass filtering to 250 Hz, and the proportional observation speed ( It is composed of a proportional integrator 216 outputting.

The solid line shown in FIGS. 2A and 2B means the variable X, and the dotted line means the reference signal η. As shown, when the estimated speed of the motor increases from 800rpm to 1100rpm, the value decreases from 1 to 0, and the estimated speed of the motor decreases from 1100rpm to 800rpm. The value increases from 0 to 1.

Further, the mode switching controller 300 decreases the variable from 1 to 0 as the estimated speed of the motor increases from 800 rpm to 1100 rpm, and particularly, when the estimated speed of the motor has the value of the first speed. The low speed region tracking loop unit 200 is turned off. Also, the mode switching controller 300 increases the variable from 0 to 1 as the estimated speed of the motor decreases from 1100 rpm to 800 rpm, and particularly, when the estimated speed of the motor has the value of the second speed. The low speed region tracking loop unit 200 is turned on.

Hereinafter, the operation of the sensorless control system of the synchronous reluctance motor according to the present invention will be described.

First, when the motor is started and at a low speed, the voltage component introduced into the motor has a relatively small value, and thus the error of the measured voltage becomes large, and the inverter unit for driving the motor is sensitive. Reaction causes difficulty in control. Therefore, there may be a problem in estimating the rotation angle of the motor rotor using the flux meter only at the time of starting the motor or at the low speed, so that a loop for estimating the position using an arbitrary signal owner method may be added to compensate for this. The loop is referred to as a low speed region tracking loop portion in the present invention.

The basic principle of the low speed area tracking loop is to apply a sinusoidal wave of proper frequency to the d-axis magnetic flux axis at start and low speed, and then if there is no position error, there is no effect of signal injection on the q-axis magnetic flux axis, and if there is a position error, the injected signal Since there will be an error synchronized with, the rotor rotation angle is estimated while controlling in the compensation direction.

In FIG. 1, the low-speed region tracking loop portion first includes an error of the q-axis magnetic flux component ( - ) Through a high pass filter with a cutoff frequency of 800 kHz to remove the DC component. Then, a value proportional to the position error is passed through a demodulation process called Demod ( ) Is multiplied by the second reference gain value '40', and then passed through the low pass filter to compensate for the proportional integrator 216. The output passing through the proportional integrator is a proportional observation speed ( ), And an estimated speed, which is speed information obtained from the flux meter of the sensorless control block, ) Is combined at an appropriate ratio by the reference signal (η) and then the observation speed ( Is called.

And the observation speed ( ) Is velocity information, so the observation rotation angle ( ), And the observed rotation angle ( ) Will gradually converge to the actual rotation angle of the actual rotor as it rotates around the low speed region tracking loop. Therefore, the observation speed (speed information) ) Will also converge at actual speed.

2A and 2B show the operation principle of the mode switching controller.

As shown, the estimated rotation angle obtained from the flux meter (sin) When the speed of the motor reaches the correct value, that is, the speed of the motor can converge to the actual rotation angle (approximately 950 rpm), the sensorless control system of the synchronous reluctance motor according to the present invention is observed rotation angle (sin Estimated rotation angle instead of ), And this will cause toggle (torqqle).

The variable (X), which means the solid line shown in FIGS. 2A and 2B, determines the amount of signal injection, and as shown, has a value of '1' when the motor is running at low speed, and ' It has a value of '0', and in the switching section (800rpm ~ 1100rpm) is reduced from '1' to '0'. That is, the variable X is determined based on the speed. Therefore, the switching between the sensorless control block and the low speed region tracking loop is ultimately made based on the speed.

However, in the case of FIG. 2, since the reference point of the switching becomes the speed, switching may occur again even with a slight shaking during the switching, such that a chattering phenomenon may occur. In particular, even after signal injection is continued after the switching to use the estimated rotation angle, the observed rotation angle observed in the low speed region tracking loop part is not actually used, so that the error of the observation rotation angle becomes larger. In order to solve the above problem, a large value of the first reference gain value 'h' may be used, but this may affect the performance of the low speed region tracking loop unit. As a result, if a phenomenon such as chattering occurs during the low / high speed mode switching, a vicious cycle may occur and sensorless control may fail.

That is, the biggest problem in the case of FIG. 2A is a difference between the estimated speed and the estimated rotation angle result of the sensorless control block and the low speed region tracking loop. In the case where there is a difference in the results between the two modes, the chattering phenomenon occurs when the mode switching is performed in the same manner as in FIG. 2A.

In other words, in the case of FIG. 2A, if the estimated speed ( ) Is the speed of observation If it is smaller than), the low speed mode is converted again. However, once the high speed mode is converted, the sensorless control performance of the low speed mode is very degraded, so the performance of the sensorless control block is deteriorated.

Figure 2b is to implement the switching between the two methods using the sensorless control block and the low-speed area tracking loop by setting the same area (hatched area), such as hysteresis band to eliminate the problem of Figure 2a. In this case, even if there is a slight difference between the speed estimate and the rotation angle estimate after switching from the low speed mode to the high speed mode, the mode switching can be prevented from being performed again, thereby enabling more stable sensorless control. Conversely, even when switching from the high speed to the low speed mode, chattering is eliminated to enable more stable sensorless control.

That is, the mode switching from the low speed to the high speed is performed at the first speed (950 to 1100 rpm), which is a higher speed, and the switching from the high speed to the low speed is performed at the second speed (800 to 950 rpm), which is a lower speed. The mode switching is achieved after the rotation angle estimate of the mode to be switched is more accurate.

Sensorless control system of the synchronous reluctance motor of the present invention configured as described above is a sensor for measuring the magnetic flux of the motor for the sensorless control of the synchronous reluctance motor and accordingly estimates the speed and rotation angle of the motor rotor The operation is determined according to a lease control block and the estimated speed of the motor, and the speed and the rotation angle of the rotor are observed to compensate the estimated speed and the estimated rotation angle of the sensorless control block at the time of starting the motor and at low speed. A low speed area tracking loop part and a mode switching control part controlling the operation of the low speed area tracking loop part according to the estimated speed and stabilizing a chattering phenomenon according to on / off of the low speed area tracking loop part. When the control system switches to low speed / high speed mode according to the low speed / high speed driving of In particular, the sensorless control system of the synchronous reluctance motor can be prevented from deteriorating the sensorless control performance of the low speed mode after switching to the high speed mode. It can work.

1 is a diagram showing the configuration of a sensorless control system of a synchronous reluctance motor according to the present invention;

2 is a graph showing the parameters of the sensorless control system of the synchronous reluctance motor according to the present invention.

<Explanation of symbols on main parts of the drawings>

100: sensorless control block 101: flux meter

102: rotation angle estimation 103: speed estimation

200: low speed region tracking loop portion 210: proportional observation speed output unit

211: flux error calculation unit 212: high pass filter

213: demodulation unit 214: second gain unit

215: low pass filter 216: proportional integrator

221: reference signal combination unit 222: observation speed calculation unit

223: integrator 224: trigonometric function conversion unit

225: rotation angle error calculation unit 226: the first gain unit

227: adding unit 300: mode switching control unit

Claims (8)

A sensorless control block for measuring the magnetic flux of the motor and estimating the speed and rotation angle of the motor rotor for sensorless control of a synchronous reluctance motor; Low-speed area tracking loop for observing the speed and the rotation angle of the rotor to determine whether the operation is determined according to the estimated speed of the motor to compensate the estimated speed and the estimated rotation angle of the sensorless control block at the time of starting the motor and low-speed driving Wealth; The on / off speed of the low speed area tracking loop part is controlled to control the operation of the low speed area tracking loop part according to the estimated speed and the on / off speed of the low speed area tracking loop part is stabilized. Sensorless control system of a synchronous reluctance motor, characterized in that it comprises a mode switching control unit that changes as time increases and when the motor speed decreases. The method of claim 1, The sensorless control block includes: a magnetic flux measuring device for outputting an estimated flux and an observer flux of the motor from a voltage and a current on a fixed coordinate system input to the motor; A rotation angle estimator for estimating a rotation angle of the motor rotor from the estimated flux and the observer flux output from the flux meter; A speed estimation section for estimating the speed of the rotor from the rotation angle estimated by the rotation angle estimation section; The low speed region tracking loop unit changes according to the estimated speed of the motor. When the estimated speed is low, the motor rotates the observed rotation angle of the rotor to the actual rotation angle according to a variable having a higher value than the high speed. Allow the observation velocity of to converge to the actual velocity; The mode switching controller senses a change in the variable, and when the estimated speed of the motor changes from a low speed to a high speed, the first speed at which the low speed region tracking loop unit is turned off, and when the speed of the motor changes from a high speed to a low speed, A sensorless control system for a synchronous reluctance motor, characterized in that for controlling the operation of the low speed region tracking loop portion to be greater than the second speed at which the low speed region tracking loop portion is turned on. The method of claim 2, The low speed region tracking loop unit comprises: a proportional observation speed output unit outputting a proportional observation speed proportional to the position of the rotor from the magnetic flux measured by the magnetic flux meter; A reference signal combination unit which combines a reference signal with a value obtained by adding the estimated speed output from the speed estimating, and the rotation angle error of the observed rotation angle and the estimated rotation angle of the rotor; An observation speed calculator configured to calculate an observation speed from an estimated speed at which the proportional observation speed and the reference signal are combined; An integrator configured to calculate an observation rotation angle by integrating the observation speed calculated by the observation speed calculator; A trigonometric function converter configured to triangulate the observed rotation angle output from the integrator and output the trigonometric function to the magnetic flux meter; A rotation angle error calculator configured to calculate an error between the observed rotation angle output from the trigonometric function converter and the estimated rotation angle of the rotor; A first gain unit which multiplies the calculated rotation angle error by a first reference gain value; And a summation unit configured to sum the rotation angle error multiplied by the first reference gain value in the first gain unit and the estimated speed, and output the summed output signal to the reference signal combination unit. . The method of claim 3, wherein The proportional observation speed output unit includes: a magnetic flux error calculation unit configured to calculate an error between the estimated magnetic flux on the q-axis and the observation magnetic flux among the magnetic flux components on the rotational coordinate system output from the magnetic flux meter; A high pass filter for high pass filtering the magnetic flux error obtained by the magnetic flux error calculating unit; A demodulator for obtaining a magnetic flux error proportional value of the motor rotor from the value filtered by the high pass filter; A second gain unit outputting a position error proportional value obtained by multiplying a magnetic flux error proportional value obtained by the demodulation unit with a second reference gain value; A low pass filter configured to low pass filter the position error proportional value output from the second gain unit; And a proportional integrator for proportionally integrating the value filtered by the low pass filter to output a proportional observation speed. The method of claim 3, wherein The reference signal is a sensorless control system of a synchronous reluctance motor, characterized in that obtained through the following equation. η = 0.8 + (10-X) * 0.2 (Wherein, η represents the reference signal and X represents a variable whose change is sensed by the mode switching controller.) The method of claim 2, The first speed has a value of 950 ~ 1100rpm and the second speed has a value of 800 ~ 950rpm, Sensorless control system of a synchronous reluctance motor. The method of claim 2, The variable is that when the estimated speed of the motor increases from 800rpm to 1100rpm, the value decreases from 1 to 0, and when the estimated speed decreases from 1100rpm to 800rpm, the value increases from 0 to 1 Sensorless control system for synchronous reluctance motors. The method of claim 7, wherein The mode switching control unit turns off the low speed region tracking loop unit when the variable decreases from 1 to 0 and the estimated speed of the motor has the first speed, and the variable increases from 0 to 1 and the estimated speed of the motor. The sensorless control system of the synchronous reluctance motor, characterized in that to turn on the low speed region tracking loop when the second speed.