JP2013255314A - Motor controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor controller which reduces six-times harmonics generated during operation of a motor without affecting a parameter identification signal and requiring a high-speed arithmetic unit.SOLUTION: A spatial harmonics reduction signal, which has an opposite phase to six-times spatial harmonics components included in d-axis and/or q-axis current signals, is superimposed on a control signal to be outputted to a motor M, thereby reducing six-times harmonics generated during operation of a motor without processing using a low-pass filter which adversely affects a parameter identification signal or processing using an active filter which requires a high-speed arithmetic unit.

Description

  The present invention relates to a motor control device that controls a motor using sensorless vector control.

  As shown in Patent Document 1, the rotational position and rotational speed of the motor are calculated and estimated from the d-axis and / or q-axis current signal flowing through the motor and the magnetic flux direction without using a position sensor or speed sensor. There is known a motor control device that controls a motor (sensorless vector control) from a comparison result between a measured value and a set value.

  When a motor is controlled by sensorless vector control, a motor voltage equation including motor parameters representing the characteristics of the motor is often used to estimate the rotational position and rotational speed of the motor during operation. And in order to identify the motor parameter which fluctuates by the temperature change during operation and the change of the current value, there is one having a configuration for injecting an identification signal for motor parameter identification into the motor control signal and identifying the motor parameter .

  However, this estimation method using the motor voltage equation is based on the premise that the influence of spatial harmonics in the voltage equation can be ignored. Therefore, if the influence of the spatial harmonics generated from the operating motor cannot be excluded, an error occurs in the estimation result. In particular, a concentrated winding IPM motor known as a high-efficiency motor is known to have a large induced voltage distortion due to a sixfold spatial harmonic due to its structural factors.

  As a method for solving such a problem, there is a spatial harmonic cancellation technique using a combination of a low-pass filter (LPF). However, by using the LPF, the motor parameter identification signal is also affected by the LPF, and an error occurs in the estimation result. There was a problem. In addition, the method of canceling spatial harmonics using an active filter requires a high-speed arithmetic device, which increases the cost.

JP 2008-86693 A

  Therefore, the present invention has been made to solve the above problems all at once, and in the motor control device, without affecting the parameter identification signal and without requiring a high-speed arithmetic device, during motor operation. The intended task is to reduce the 6-fold spatial harmonics that are generated.

  That is, the motor control device according to the present invention estimates the position of the rotor using the d-axis and / or q-axis current signal flowing through the motor, and outputs a control signal to the motor according to the estimated rotor position, thereby sensorless. In the motor control apparatus that performs vector control, a spatial harmonic reduction signal having a phase opposite to that of the 6-fold spatial harmonic component included in the d-axis and / or q-axis current signal is superimposed on the control signal and is applied to the motor. It is characterized by outputting.

  If this is the case, the spatial harmonic reduction signal having the opposite phase to the 6-times spatial harmonic component included in the d-axis and / or q-axis current signal is superimposed on the control signal and output to the motor. 6x spatial harmonics generated during motor operation without processing using LPF or the like that adversely affects the motor parameter identification signal and processing using active fill or the like that requires a high-speed arithmetic device. Waves can be reduced.

  By outputting to the motor while alternately changing the amplitude and phase of the spatial harmonic reduction signal with respect to the 6-fold spatial harmonic component contained in at least one of the d-axis or q-axis current signal, the amplitude When changing either of the phase and the phase, by fixing the other value, the respective optimum values can be detected without being influenced by the other.

  An adaptive amplitude generation step of detecting only the amplitude of the spatial harmonic reduction signal in which only the amplitude of the spatial harmonic reduction signal is changed and the 6-fold spatial harmonic component is a minimum value; and the phase of the spatial harmonic reduction signal And an adaptive phase generation step of detecting a phase of the spatial harmonic reduction signal at which the 6-times spatial harmonic component has a minimum value, and the spatial harmonic reduction signal of the adaptive amplitude generation step The phase is fixed to a phase at which the 6-fold spatial harmonic component becomes a minimum value in the immediately preceding adaptive phase creating step, and the amplitude of the spatial harmonic reduction signal in the adaptive phase creating step is set to the immediately preceding adaptive amplitude creating In the step, it is desirable to fix the amplitude at which the 6th spatial harmonic component is a minimum value. In this case, when changing either the amplitude or the phase, the other value is fixed to the optimum value and changed, and then the optimum value of either the amplitude or the phase is detected and this is detected. By repeating the above, the 6-fold spatial harmonic can be brought close to the minimum value.

  Even if the motor is a motor that has a large induced voltage distortion due to a 6th spatial harmonic, such as an IPM motor, the above-described configuration is obtained because the main component of the generated harmonic is a 6th spatial harmonic component. In this case, the 6-fold spatial harmonic can be reduced.

  The control program according to the present invention estimates the position of the rotor using the d-axis and / or q-axis current signal flowing through the motor, and outputs a control signal to the motor according to the estimated rotor position to perform sensorless vector control. For superimposing a spatial harmonic reduction signal having a phase opposite to that of a 6-fold spatial harmonic component included in the d-axis and / or q-axis current signal on the control signal. This is characterized in that the motor control device exhibits the above.

  According to the present invention configured as described above, the motor is obtained by superimposing a spatial harmonic reduction signal having a phase opposite to that of the 6-times spatial harmonic component included in the d-axis and / or q-axis current signal on the control signal. 6 times that occurs during motor operation without performing processing using LPF or the like that adversely affects the motor parameter identification signal and processing using active fill or the like that requires a high-speed arithmetic device. Spatial harmonics can be reduced.

The block diagram which shows typically the motor control apparatus which concerns on one Embodiment of this invention. The flowchart which shows the harmonic reduction control which concerns on the same embodiment. The d-axis and q-axis current waveforms before the 6-fold spatial harmonic reduction according to the same embodiment. The d-axis and q-axis current waveforms after 6-fold spatial harmonic reduction according to the embodiment.

  Hereinafter, an embodiment of a clothes dryer according to the present invention will be described with reference to the drawings.

  FIG. 1 shows a motor control apparatus 100 according to the present invention. In the figure, the electric motor M to be controlled is also shown. The motor M is a concentrated winding IPM motor used for electric vehicles and compressors, and is easily affected by induced voltage distortion caused by spatial harmonics.

  The motor control device 100 uses position sensorless vector control to control the rotational speed of a rotor (not shown) to a preset speed, and is physically an electric circuit including a CPU, a memory, and the like. It is constituted by. Then, when the CPU and its peripheral devices operate according to the program stored in the memory, as shown in FIG. 1, the inverter 1, the current detection unit 2, the output coordinate conversion unit 3, the phase estimation unit 4, the speed estimation Functions as the unit 5, the speed control unit 6, the current control unit 7, the input coordinate conversion unit 8, and the like are exhibited.

  Furthermore, the motor control device 100 includes a motor parameter identification unit 9 that identifies various motor parameters used in the phase estimation unit 4, a spatial harmonic reduction unit 20 that reduces the influence of spatial harmonics generated from the motor M, Is provided.

  Next, an outline of the position sensorless vector control here will be described together with description of each part of the motor control device 100.

  The current of each phase (three phases) flowing through the motor M driven by the inverter 1 is detected by the current detection unit 2, and the output coordinate conversion unit 3 (three phase / 2 phase conversion unit) is a virtual control axis, that is, the d axis. And two-phase currents id and iq flowing in the q-axis, respectively.

  Then, based on the d-axis current id and the q-axis current iq, the phase estimation unit 4 estimates the estimated phase (position, rotation angle) of the rotor with reference to the control axis using a motor voltage equation described later.

  Further, a position error estimating unit (not shown) calculates and estimates a phase error Δθ that is an error between the estimated phase estimated by the phase estimating unit 4 and the actual rotor phase. Here, since there is no position sensor, the motor M of this embodiment is not provided with an encoder or the like for measuring the rotation angle. Therefore, the actual rotor phase is not directly measured by an encoder or the like, but is a value calculated by, for example, a target rotational speed described later. Thereafter, the speed estimator 5 performs a PLL calculation to calculate and estimate the rotor rotational speed ω ^ so that the phase error Δθ is zero.

  Then, the speed control unit 6 calculates a q-axis current command value based on a deviation between the estimated rotation speed ω ^ and a predetermined set rotation speed, and the current control unit 7 further calculates the q-axis current command value. A q-axis voltage Vq to be applied to the motor M is calculated based on the deviation from the q-axis current Iq, and is output to the input coordinate conversion unit 8 as a control signal together with the calculated d-axis voltage Vd.

  Further, the input coordinate conversion unit 8 (2-phase / 3-phase conversion unit) converts the voltage value to a three-phase voltage value to be applied to the motor M based on the d-axis voltage Vd and the q-axis voltage Vq.

  The above is the outline of the position sensorless vector control. In this embodiment, the motor parameter identification unit 9 further identifies the motor parameters and sequentially updates them to reflect changes in the motor parameters due to temperature changes and the like. Thus, the estimation accuracy in the phase estimation unit 4 is improved.

  Below, the structure and operation | movement of the phase estimation part 4 and the motor parameter identification part 9 are explained in full detail.

  The phase estimation unit 4 is configured to estimate the estimated phase θ_est based on the following motor voltage equation.

Here, Vd: d-axis voltage, Vq: q-axis voltage, id: d-axis current, iq: q-axis current, Ld: d-axis inductance, Lq: q-axis inductance, R: impedance, φ: interlinkage magnetic flux, ΔV : Voltage drop, ω: Electrical angular velocity, p: Differential operator, Dd: Voltage drop component d-axis converted value, Dq: Voltage drop component q-axis converted value, L _* : Spatial harmonic component due to impedance, φ _* : Magnetic flux It is a spatial harmonic component. Among these values, the motor parameters to be identified by the motor parameter identifying unit 9 are the q-axis inductance Lq, the voltage drop ΔV, the impedance R, and the linkage flux φ, and these values are initially designed values and the like. Is used as the initial value.

Further, the spatial harmonic component due to impedance and the spatial harmonic component due to magnetic flux in the motor voltage equation of Equation 1 are described as follows.

Furthermore, the voltage drop component conversion value to each axis in the motor voltage equation of Equation 1 is described as follows.

  The motor parameter identification unit 9 is configured to identify a motor parameter used in the phase estimation unit 4 based on a voltage value applied to the motor M or a current value flowing through the motor M. More specifically, the motor parameter identification unit 9 determines an identification voltage value that is a voltage value applied to the motor M when the phase of the control rotation shaft of the motor M reaches a predetermined phase, or the motor M The motor parameter is identified based on an identification current value that is a current value flowing through the motor M when the phase of the control rotation shaft becomes a predetermined phase. The motor parameter identification unit 9 acquires the current value output from the output coordinate conversion unit 3 and also acquires the voltage value commanded to be applied to the motor M by the current control unit 7. is there. When the phase estimated by the phase estimation unit 4 becomes a predetermined phase, or when the phase obtained by time integration of the target rotation speed becomes a predetermined phase, the voltage value and current value at that time are Use to identify each motor parameter. The motor parameter identification unit 9 sequentially updates the motor parameters used for phase estimation by the phase estimation unit 4 to the identified values.

  Here, in the conventional motor parameter identification method, the influence of the spatial harmonics in the third and fourth terms on the right side in the motor voltage equation of Equation 1 is ignored, or the spatial harmonics are suppressed by spatial harmonic suppression technology. It is assumed that identification can be performed in a state where the motor M itself does not act. However, as shown in FIG. 3, in actuality, during operation of the motor M, spatial harmonics mainly including a 6-fold spatial harmonic component that cannot be ignored in the calculation are generated. It is necessary to reduce the spatial harmonics to the extent that the values of the terms and the fourth term are zero or can be ignored in calculation.

  Next, a method for reducing spatial harmonics will be described in conjunction with the explanation of the spatial harmonic reduction unit 20. In this method, a spatial harmonic reduction signal IS having a phase opposite to that of the 6th spatial harmonic component, which is the main component of the spatial harmonic included in the d-axis or q-axis current signal, is superimposed on the control signal and output to the motor M. Thus, the 6-fold spatial harmonic component generated during operation of the motor M is reduced.

  In general, in the case of an electric motor, the harmonic component included in the current waveform is mainly the sixth harmonic component of the fundamental wave, and the amplitude of the entire harmonic component is almost the same as the amplitude of the sixth harmonic component. There are many cases. Therefore, if the 6th harmonic component is reduced, all the harmonic components can be reduced.

  The spatial harmonic reduction unit 20 includes a sixth harmonic amplitude detection unit 21 and a phase / amplitude control unit 22.

  First, the 6th harmonic amplitude detection unit 21 detects the amplitude of the 6th spatial harmonic component from the two-phase d-axis current id and q-axis current iq converted by the output coordinate conversion unit 3. The detected amplitude of the 6th spatial harmonic component is output from the 6th harmonic amplitude detection unit 21 to the phase / amplitude control unit 22.

  Next, a base signal BS that is the basis of the spatial harmonic reduction signal IS is created. Since it is known that the frequency of the target 6-times spatial harmonic component is 6 times the current applied to the motor M, it is 6 times the fundamental wave applied to the motor M estimated by the speed estimation unit 5. The base signal BS having the opposite phase and the opposite phase is created. The generated base signal BS is input to the phase / amplitude control unit 22.

  Then, the phase / amplitude control unit 22 creates the spatial harmonic reduction signal IS by alternately changing the amplitude and phase based on the acquired base signal BS. By superimposing the spatial harmonic reduction signal IS on the control signal output from the current control unit 7 to the input coordinate conversion unit 8, the amplitude of the 6-fold spatial harmonic component changes. At this time, since the amplitude of the 6-fold spatial harmonic component detected by the 6-fold harmonic amplitude detector 21 changes, control is performed so that the spatial harmonic reduction signal IS is such that the amplitude approaches the minimum value.

  The control of the phase / amplitude control unit 22 will be specifically described. First, an adaptive amplitude generation step Sa is performed in which the phase of the base signal BS is fixed and only the amplitude is changed within a predetermined range to generate the spatial harmonic reduction signal IS. At this time, if the 6-fold spatial harmonic component and the spatial harmonic reduction signal IS have the same amplitude and the phase is nearly opposite, the 6-fold spatial harmonic component is smaller than before the superposition. When the phases are close to each other, the 6-fold spatial harmonic component is larger than before the superposition.

  Then, an adaptive amplitude in which the amplitude of the 6th spatial harmonic component is the smallest is detected within a range in which only the amplitude of the spatial harmonic reduction signal IS is changed. Next, an adaptive phase creation step Sp is performed in which the spatial harmonic reduction signal IS is fixed to the adaptive amplitude and only the phase is changed within a predetermined range to create the spatial harmonic reduction signal IS. At this time, when the phase of the 6th spatial harmonic component and the spatial harmonic reduction signal IS are close to each other, the 6th spatial harmonic component is smaller than before superposition and the phase is the same. In the near case, the 6-fold spatial harmonic component becomes larger than before the superposition.

  Then, an adaptive phase in which the amplitude of the 6th spatial harmonic component is the smallest is detected within a range in which only the phase of the spatial harmonic reduction signal IS is changed. Then, the phase of the spatial harmonic reduction signal IS when the adaptive phase is detected is fixed as the adaptive phase, and the process proceeds to the adaptive amplitude creation step Sa.

  Thereafter, since the amplitude and phase of the 6-fold spatial harmonic component change due to a change in the rotational speed of the motor M, the adaptive amplitude creation step Sa and the adaptive phase creation step Sp are continuously performed alternately. The creation of the spatial harmonic reduction signal IS in accordance with is continued. By performing such processing, as shown in FIG. 4, it is possible to reduce spatial harmonics that adversely affect the motor parameter identification method.

  Note that the initial amplitude of the base signal BS needs to be set to a certain level. This is because if the amplitude of the spatial harmonic reduction signal IS is too small, the detected 6-fold spatial harmonic component does not change when the spatial harmonic reduction signal IS is superimposed on the control signal, and the above-described control can be performed. This is to prevent disappearance. Similarly, if the minimum amplitude value when the amplitude is changed in the adaptive amplitude generation step Sa is also set to an amplitude smaller than the resolution of the 6th harmonic amplitude detection unit 21, a change in the 6th spatial harmonic component is detected. Therefore, it is necessary to set the minimum amplitude value in consideration of the resolution of the sixth harmonic amplitude detector 21.

<Other modified embodiments>
The present invention is not limited to the above embodiment. For example, in the embodiment, the adaptive amplitude creation step Sa is performed with the phase fixed first, but the adaptive phase creation step Sp may be performed with the amplitude fixed first.

  In addition, when the control for greatly changing the phase of the current flowing through the motor M, such as field weakening control, is performed, the phase of the base signal BS is also greatly changed. Therefore, when the phase of the current flowing through the motor M changes, the changed phase is calculated, and the phase component of the base signal BS is corrected, so that the 6-times spatial harmonic component changes abruptly. Therefore, abnormal noise and abnormal vibration can be prevented.

  Further, in the state where the motor parameter identification signal is applied, the current flowing through the motor M is affected by the motor parameter identification signal because the detection of the spatial harmonic amplitude is affected by the motor parameter identification signal. The space harmonic amplitude is not detected during the interval.

  Further, when the rotational speed of the motor M changes suddenly, if the conditions of the 6-fold spatial harmonic component and the spatial harmonic reduction signal IS do not match, the spatial harmonic reduction signal IS is superimposed on the control signal. This may cause a rapid increase in the 6-fold spatial harmonic component. Therefore, when the number of rotations of the motor M changes rapidly, it is conceivable that the amplitude of the base signal BS is reduced as much as possible and at least a 6-fold spatial harmonic component is not increased.

  Furthermore, since the spatial harmonics generated from the motor M are generated in both the d-axis and q-axis currents, it is desirable to superimpose the spatial harmonic reduction signal IS on each, but the required reduction of the spatial harmonics Depending on the target, it may be superimposed on only one of the d-axis and q-axis currents.

  Further, the spatial harmonic reduction method of the present invention is not limited to the 6-fold spatial harmonic component. For example, if it is known how many times (n times) the harmonic component of the fundamental wave is the main component of the spatial harmonics generated in advance, each base signal BS is set to n times the fundamental wave, It is possible to deal with n-times harmonic components.

  In addition, it goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 100 ... Motor control apparatus 1 ... Inverter 2 ... Current detection part 3 ... Output coordinate conversion part 4 ... Phase estimation part 5 ... Speed estimation part 6 ... Speed control part 7 ··· Current control unit 8 ··· Input coordinate conversion unit 9 ··· Motor parameter identification unit 20 ··· Spatial harmonic reduction unit 21 ··· Sixth harmonic amplitude detection unit 22 ··· Phase / amplitude control unit BS ... Base signal IS ... Spatial harmonic reduction signal Sa ... Adaptive amplitude creation step Sp ... Adaptive phase creation step M ... Motor

Claims (5)

In a motor control device that estimates a rotor position using a d-axis and / or q-axis current signal flowing through a motor and outputs a control signal to the motor in accordance with the estimated rotor position to perform sensorless vector control.
A motor control device characterized in that a spatial harmonic reduction signal having a phase opposite to that of a 6-fold spatial harmonic component contained in the d-axis and / or q-axis current signal is superimposed on the control signal and output to the motor. .   Output to the motor while alternately changing the amplitude and phase of the spatial harmonic reduction signal with respect to the 6-fold spatial harmonic component contained in at least one of the d-axis or q-axis current signals. The motor control device according to claim 1. An adaptive amplitude generating step of detecting only the amplitude of the spatial harmonic reduction signal in which only the amplitude of the spatial harmonic reduction signal is changed and the 6-times spatial harmonic component is a minimum value;
An adaptive phase creating step of detecting only the phase of the spatial harmonic reduction signal in which only the phase of the spatial harmonic reduction signal is changed and the 6th spatial harmonic component is a minimum value;
Fixing the phase of the spatial harmonic reduction signal in the adaptive amplitude creation step to a phase at which the 6-fold spatial harmonic component is a minimum value in the immediately preceding adaptive phase creation step;
The amplitude of the spatial harmonic reduction signal in the adaptive phase creation step is fixed to an amplitude at which the 6-fold spatial harmonic component becomes a minimum value in the immediately preceding adaptive amplitude creation step. Motor control device.   The motor control device according to claim 1, wherein the motor is an IPM motor. Used in a motor control device that estimates the position of the rotor using d-axis and / or q-axis current signals flowing through the motor and outputs a control signal to the motor according to the estimated rotor position to perform sensorless vector control. It can be
A control program for causing a motor control device to exert a function of superimposing a spatial harmonic reduction signal having a phase opposite to that of a 6-fold spatial harmonic component included in the d-axis and / or q-axis current signal on the control signal.