JP6248791B2 - Motor control method and motor control apparatus - Google Patents

Description

  The present disclosure relates to a control technique in a motor control device having an inverter that drives a motor.

  A technique for estimating a position of a rotor of a motor necessary for controlling the motor without a position sensor is known. Information on motor current and voltage is used for position estimation. In order to accurately estimate the position, it is necessary to detect the motor current and voltage with high accuracy. For example, if the motor voltage information cannot be obtained correctly and stably, an error occurs in the estimated position, and the motor cannot be appropriately controlled.

  Patent Document 1 describes an example of a control device that stores an error between a voltage command value and an output voltage to a motor and corrects the voltage command value using the error.

Japanese Patent Laid-Open No. 10-164850

  However, according to the technique of Patent Document 1, only the voltage command value is corrected, and the estimation accuracy of the position of the rotor cannot be improved. For this reason, this technique cannot be adopted when controlling a motor without a position sensor. Further, when the output current fluctuates due to a disturbance or the like, the required error immediately increases, the voltage command value fluctuates immediately, and stable control becomes difficult.

  An object of the present invention is to stably obtain a time average of phase voltages of a motor and estimate the position of a rotor of the motor more accurately.

1st invention is a motor control method which drives a motor (4) using a PWM signal (C), Comprising: The pulse width of the phase voltage (Vu, Vv, or Vw) supplied to the said motor (4) is set. Detected as a pulse width detection value (Wu, Wv or Ww), the pulse width command value (Wu ^* , Wv ^* or Ww ^* ), which is the pulse width of the PWM signal (C), and the pulse width of the corresponding phase The phase of the motor (4) is based on the relationship obtained in advance between the error between the detected value (Wu, Wv or Ww) and the phase current of the corresponding phase of the motor (4). A pulse width error prediction value (Wuep, Wvep or Wwep) is obtained from the current detection value (Iu, Iv or Iw), and the pulse width command value (Wu ^* , Wv ^* or Ww ^* ) is calculated as the pulse width error prediction value ( Correction using Wuep, Wvep or Wwep) to obtain a pulse width predicted value (Wup, Wvp or Wwp), and the pulse width detection value (Wu, Wv or Ww) is determined as the pulse width predicted value. Wup, Wvp or Wwp) is used to correct the disturbance so as to reduce the influence of the disturbance, and the corrected pulse width (Wua, Wva or Wwa) is obtained, and the corrected pulse width (Wua, Wva or Wwa) is obtained. ) To obtain an output voltage detection value (Vua, Vva or Vwa) which is a time average of the phase voltage (Vu, Vv or Vw), and using the output voltage detection value (Vua, Vva or Vwa), the motor Estimate the rotor position (θ) in (4).

In the first invention, an error corresponding to the phase current detection value (Iu, Iv, or Iw) of the motor (4) is obtained as a pulse width error prediction value (Wuep, Wvep, or Wwep) based on a previously obtained relationship. The pulse width command value (Wu ^* , Wv ^* or Ww ^* ) is corrected using the pulse width error prediction value (Wuep, Wvep or Wwep) to obtain the pulse width prediction value (Wup, Wvp or Wwp), The pulse width detection value (Wu, Wv, or Ww) is corrected using the pulse width prediction value (Wup, Wvp, or Wwp) so that the influence of disturbance is reduced. Thereby, the corrected pulse width (Wua, Wva or Wwa) can be obtained more accurately and stably. For this reason, even if it receives disturbance, the time average of the phase voltage of the motor (4) can be obtained stably, and the position of the rotor of the motor (4) can be estimated more accurately.

  According to a second invention, in the first invention, when the phase current detection value (Iu, Iv or Iw) of the motor (4) is smaller than a predetermined value, the pulse width detection value (Wu, Wv or Ww) is used as the corrected pulse width (Wua, Wva or Wwa).

According to the second invention, when the current output to the motor (4) is small, the error in the pulse width is also small, so that the processing can be simplified. In general, when the current output to the motor (4) is small, the pulse width command value (Wu ^* , Wv ^* or Ww ^* ) and the pulse width detection value (Wu, Wv or Ww) when the current changes The error between and changes greatly. According to the second invention, even if an error occurs between the actual current and the detected phase current of the motor (4), the estimation of the rotor position can be prevented from being affected.

  According to a third invention, in the first or second invention, a difference between the predicted pulse width value (Wup, Wvp or Wwp) and the detected pulse width value (Wu, Wv or Ww) is calculated as a pulse width error ( Wue, Wve or Wwe), smoothing the pulse width error (Wue, Wve or Wwe) to obtain a smoothed pulse width error (Wuf, Wvf or Wwf), and calculating the pulse width predicted value (Wup, The sum of Wvp or Wwp) and the smoothed pulse width error (Wuf, Wvf or Wwf) is obtained as the corrected pulse width (Wua, Wva or Wwa).

  In the third invention, the difference between the pulse width predicted value (Wup, Wvp or Wwp) and the pulse width detection value (Wu, Wv or Ww) is obtained as a pulse width error (Wue, Wve or Wwe). Smooth the pulse width error (Wue, Wve or Wwe). As a result, the characteristics of the circuit that drives the motor (4) can be obtained as an offset that does not vary much even if the current output to the motor (4) varies, and the corrected pulse width (Wua, Wva or Wwa) It can be obtained more accurately and stably.

  In a fourth aspect based on the third aspect, when the absolute value of the pulse width error (Wue, Wve or Wwe) is larger than a predetermined value, the smoothed pulse width error ( Wuf, Wvf or Wwf) is used.

  According to the fourth invention, when the noise is relatively large, the previously obtained value is selected, so that it is less susceptible to the influence of disturbance.

  In a fifth aspect according to the third aspect, when it is continuously detected a predetermined number of times that the absolute value of the pulse width error (Wue, Wve or Wwe) for the same phase is larger than a predetermined value. The sensor that measures the phase voltage (Vu, Vv, or Vw) of the phase is determined to have failed.

  According to the fifth aspect of the invention, it is possible to detect the failure of the sensor that measures the phase voltage (Vu, Vv, or Vw).

  In a sixth aspect based on the fifth aspect, when it is determined that the sensor has failed, the predicted pulse width (Wup, Wvp or Wwp) for the phase is changed to the corrected pulse width (Wua). , Wva or Wwa).

  In the sixth aspect of the invention, since the predicted pulse width (Wp) is used as the corrected pulse width (Wua, Wva or Wwa), the pulse width detection value (Wu, Vv) obtained from the phase voltage (Vu, Vv or Vw) is used. It is not necessary to use Wv or Ww), and the motor (4) can be continuously driven even if the sensor for measuring the phase voltage (Vu, Vv or Vw) fails.

  In a seventh invention, in the first invention, the previously obtained relationship is stored as an equation, and based on the equation, the phase current detection value (Iu, Iv or Iw) of the motor (4) is stored. The corresponding error is calculated as the pulse width error prediction value (Wuep, Wvep or Wwep).

  In the seventh invention, an error corresponding to the current output to the motor (4) is calculated as a pulse width error prediction value (Wuep, Wvep or Wwep) using an equation. For this reason, compared with the case where the error corresponding to the current output to the motor (4) is stored as a table, the required storage capacity can be significantly reduced.

The eighth invention is a motor control device for driving a motor (4) using a PWM signal (C), wherein the pulse width of the phase voltage (Vu, Vv or Vw) supplied to the motor (4) is determined. A pulse width detection unit (32) that detects a pulse width detection value (Wu, Wv, or Ww), a pulse width command value (Wu ^* , Wv ^*, or Ww ^* ) that is the pulse width of the PWM signal (C), and this Based on a previously determined relationship between an error between the pulse width detection value (Wu, Wv, or Ww) of the phase corresponding to and the phase current of the corresponding phase of the motor (4) The pulse width error prediction value (Wuep, Wvep or Wwep) is obtained from the phase current detection value (Iu, Iv or Iw) of the motor (4), and the pulse width command value (Wu ^* , Wv ^* or Ww ^* ) is obtained. The pulse width error correction value (Wuep, Wvep or Wwep) is used for correction to obtain the pulse width prediction value (Wup, Wvp or Wwp), and the pulse width detection value (Wu, Wv) Ww) is corrected using the predicted pulse width value (Wup, Wvp or Wwp) so that the influence of disturbance is reduced, and the pulse width for obtaining the corrected pulse width (Wua, Wva or Wwa) An output voltage detection value (Vua, Vva) which is a time average of the phase voltage (Vu, Vv or Vw) using the correction unit (40; 240; 340) and the corrected pulse width (Wua, Wva or Wwa). Alternatively, an output voltage calculation unit (34) for obtaining Vwa) and a position estimation unit (26) for estimating the rotor position (θ) of the motor (4) using the output voltage detection value (Vua, Vva or Vwa). And have.

In the eighth invention, the pulse width correction unit (40; 240; 340) pulses an error corresponding to the phase current detection value (Iu, Iv or Iw) of the motor (4) based on the relationship obtained in advance. Obtained as a width error prediction value (Wuep, Wvep or Wwep). The pulse width correction unit (40; 240; 340) corrects the pulse width command value (Wu ^* , Wv ^* or Ww ^* ) using the predicted pulse width error value (Wuep, Wvep or Wwep), and the pulse width The predicted value (Wup, Wvp or Wwp) is obtained, and the pulse width detection value (Wu, Wv or Ww) is used as the pulse width predicted value (Wup, Wvp or Wwp) so that the influence of disturbance is reduced. to correct. Thereby, the corrected pulse width (Wua, Wva or Wwa) can be obtained more accurately and stably. For this reason, even if it receives disturbance, the time average of the phase voltage of the motor (4) can be obtained stably, and the position of the rotor of the motor (4) can be estimated more accurately.

  According to the 1st-8th invention, the time average of the phase voltage of a motor can be calculated | required stably. Therefore, it is possible to estimate the position of the rotor of the motor with higher accuracy and drive the motor.

It is a circuit diagram showing an example of composition of a motor control device concerning an embodiment of the present invention. It is a block diagram which shows the structural example of the controller of FIG. It is a block diagram which shows the structural example of the voltage calculating part of FIG. It is a block diagram which shows the structural example of the pulse width correction | amendment part of FIG. It is a graph which shows the example of the voltage of the signal in FIG.1 and FIG.2. It is a graph which shows the example of the error between a pulse width command value and a pulse width detection value. It is a block diagram which shows the other structural example of the pulse width correction | amendment part of FIG. It is a block diagram which shows the further another structural example of the pulse width correction | amendment part of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present specification, components having the same reference numerals in the last two digits correspond to each other and are the same or similar components. In addition, u, v, and w of the second character in codes such as Iu, Iv, and Iw indicate values of the u phase, the v phase, and the w phase, respectively.

  FIG. 1 is a circuit diagram showing a configuration example of a motor control device (10) according to an embodiment of the present invention. The motor control device (10) in FIG. 1 has a converter (12), a smoothing capacitor (14), an inverter (16), and a controller (20) that generates a PWM (pulse width modulation) signal (C). Then, the motor (4) is driven using the PWM signal (C).

  The converter (12) has six diodes (Dr) connected in a bridge shape, converts the three-phase alternating current of the three-phase alternating current power supply (2) into direct current and outputs the direct current. The smoothing capacitor (14) smoothes the DC voltage output from the converter (12). The inverter 16 includes an IGBT (Insulated Gate Bipolar Transistor) (Tr) as a switching element and six free-wheeling diodes (also referred to as FWD) (Dw) connected in antiparallel to each of these IGBTs (Tr). Have. The inverter (16) converts the smoothed DC voltage into a three-phase AC voltage and supplies it to the three-phase motor (4). Each IGBT (Tr) is controlled by a PWM signal (C). The three-phase motor (4) is, for example, a motor for rotationally driving a compressor included in an air conditioner or a refrigeration apparatus. In this embodiment, the case where an IGBT is used as a switching element will be described. However, other elements such as other types of transistors may be used as the switching element.

  The controller (20) receives the phase current detection values (phase current detection values) (Iu, Iv, Iw) of the phases supplied to the three-phase motor (4). The controller (20) generates a PWM signal (C) so that these phase currents become three-phase alternating current, and outputs them to the control terminals of the six IGBTs (Tr) built in the inverter (16). Controls the rotation speed of the three-phase motor (4).

FIG. 2 is a block diagram illustrating a configuration example of the controller of FIG. The controller (20) in FIG. 2 includes a current control unit (22), a PWM signal generation unit (24), a position estimation unit (26), and a voltage calculation unit (30). The current control unit (22) outputs to the motor (4) based on the current command value (I ^* ), the phase current detection value (Iu, Iv, Iw), and the rotor position (θ) of the motor (4). A voltage command value (V ^* ) is generated and output so that the current that follows the current command value (I ^* ) follows. The current control unit (22) generates a voltage command value (V ^* ) using, for example, PI (proportional integral) control. The PWM signal generator (24) generates a PWM signal (C) based on the voltage command value (V ^* ) and the rotor position (θ) and outputs the PWM signal (C) to the inverter (16). Further, the PWM signal generation unit (24) outputs the pulse width of each phase of the PWM signal (C) to the voltage calculation unit (30) as a pulse width command value (Wu ^* , Wv ^* , Ww ^* ).

  The voltage calculation unit (30) is based on the phase voltage (Vu, Vv or Vw) supplied to the motor (4), etc., and the output voltage detection value that is the respective time average of the phase voltage (Vu, Vv or Vw) (Vua, Vva or Vwa) is obtained. The position estimation unit (26) estimates the rotor position (θ) of the motor (4) based on the output voltage detection value (Vua, Vva or Vwa) and the phase current detection value (Iu, Iv or Iw), Output. The position (θ) of the rotor of the motor (4) is indispensable for the motor current control. When the control is performed without using the rotor position sensor, it is necessary to estimate the position (θ) of the rotor. . In this embodiment, the time average of the phase voltage supplied to the motor (4) is obtained more accurately and stably as the output voltage detection value (Vua, Vva or Vwa), so that the position of the rotor ( θ) can be estimated continuously with high accuracy. The output voltage detection values (Vua, Vva, Vwa) are all values for appropriate periods such as one carrier cycle (Tc).

FIG. 3 is a block diagram illustrating a configuration example of the voltage calculation unit of FIG. The voltage calculation unit (30) in FIG. 3 includes a pulse width detection unit (32), an output voltage calculation unit (34), and a pulse width correction unit (40). The pulse width detector (32) detects and outputs the pulse width of each phase voltage (Vu, Vv or Vw) supplied to the motor (4) as a pulse width detection value (Wu, Wv or Ww). The pulse width correction unit (40) corrects the pulse width detection value (Wu, Wv or Ww) so that the influence of disturbance such as noise is reduced, and corrects the corrected pulse width (Wua, Wva or Wwa). ) At this time, the pulse width correction unit (40) calculates an error between the pulse width command value (Wu ^* , Wv ^* or Ww ^* ) and the corresponding pulse width detection value (Wu, Wv or Ww). , Which is a relationship between the phase current of the corresponding phase of the motor (4) output from the inverter (16) (for example, the time average of the detected phase current value (Iu, etc.)) Is used.

The output voltage calculation unit (34) obtains an output voltage detection value (Vua, Vva or Vwa) based on the corrected pulse width (Wua, Wva or Wwa) and the voltage (VDC) of the smoothing capacitor (14), and positions Output to the estimation unit (26). Specifically, for the u phase, for example, the output voltage calculation unit (34) uses the carrier period (Tc),
Vua = VDC x Wua / Tc
The output voltage detection value (Vua) is obtained for each cycle by adding the influence of the voltage drop (ON voltage) when the IGBT (Tr) and the freewheeling diode (Dw) are conducted to the output voltage detection value (Vua). Output as. In other words, the output voltage calculation unit (34) divides the area between the voltage (Vu) and the horizontal axis in FIG. 5 (if the voltage (Vu) is negative) by the period, An output voltage detection value (Vua) that is a time average of the voltage (Vu) is obtained. The same applies to the v phase and the w phase.

  FIG. 4 is a block diagram illustrating a configuration example of the pulse width correction unit in FIG. The pulse width correction unit (40) in FIG. 4 includes a pulse width error calculation unit (42), an adder (44, 48), a subtracter (46), and a filter (52). Perform the process. The pulse width correction unit (40) further has two configurations shown in FIG. 4, which perform processing for the v-phase and the w-phase, respectively.

FIG. 5 is a graph showing an example of the voltage of the signal in FIGS. 1 and 2. As shown in FIG. 5, the u-phase upper arm PWM signal (C) has a pulse width (Wuu ^* ), and the u-phase lower arm PWM signal (C) has a pulse width (Wul ^* ). The w-phase upper arm PWM signal (C) has a pulse width (Wwu ^* ), and the w-phase lower arm PWM signal (C) has a pulse width (Wwl ^* ). These pulse widths are periods of pulses that cause the output voltage to the motor (4) to become “high”. FIG. 5 also shows a dead time (Td) for preventing a through current. When the phase current is positive (for example, when the current goes to the motor (4)), the PWM signal generation unit (24) outputs the pulse width of the upper arm PWM signal for the phase as a pulse width command value. When the phase current is negative, the pulse width of the lower arm PWM signal for that phase is output as the pulse width command value.

In the case of FIG. 5, since the u-phase current value (Iu) is negative and the w-phase current value (Iw) is positive, the PWM signal generation unit (24) outputs the u-phase pulse width command value (Wu ^*) to output the pulse width (WUL ^*) as to output pulse width command value of w phase (Ww ^*) as the pulse width (WWU ^*). As shown in FIG. 5, a rise delay (Dup) occurs when the IGBT (Tr) in FIG. 1 is turned on, and a fall delay (Ddw) occurs when the IGBT (Tr) is turned off. An error occurs between the width command value (Wu ^*, etc.) and the pulse width detection value (Wu, etc.).

FIG. 6 is a graph showing an example of an error between a pulse width command value (Wu ^*, etc.) and a pulse width detection value (Wu, etc.). As shown in FIG. 6, this error varies according to the magnitude of the phase current (time average of the phase current detection value (Iu, etc.)) output from the inverter (16) to the motor (4). The points plotted in FIG. 6 can be divided into three groups (G1, G2, G3). When a regression line is obtained for each of the groups (G1, G2, G3), three straight lines (L1, L2, L3) are obtained as shown in FIG. A relationship represented by a straight line as shown in FIG. 6 is obtained in advance using an inverter (16) having a standard characteristic as shown in FIG. The relationship shown in FIG. 6 may be obtained in advance using several inverters (16). In FIG. 6, the vertical axis value 200 corresponds to, for example, about 5 μs.

The u phase will be described with reference to FIG. The pulse width error calculation unit (42) in FIG. 4 calculates the difference between the error between the pulse width command value (Wu ^* ) and the pulse width detection value (Wu) and the u-phase current of the motor (4). In this way, a formula representing the relationship obtained in advance (here, a formula representing three straight lines (L1, L2, L3)) is stored. FIG. 6 is an example, and other numbers of straight lines may be obtained, and the equation of these straight lines may be stored in the pulse width error calculation unit (42). Such a formula is commonly used for the u phase, the v phase, and the w phase. Since the error is obtained using the equation in this way, the required storage capacity can be significantly reduced as compared with the case where the error corresponding to the current output to the motor (4) is stored as a table.

  The pulse width error calculation unit (42) obtains the time average of the phase current detection value (Iu) as the phase current output to the motor (4). This time average is a value for each appropriate period such as one carrier period (Tc) in FIG. The pulse width error calculation unit (42) calculates and outputs an error corresponding to the obtained time average as a pulse width error prediction value (Wuep) based on the stored straight line equation. The pulse width error calculation unit (42) may determine the instantaneous value of the phase current detection value (Iu) as the phase current output to the motor (4).

The adder (44) obtains the sum of the pulse width command value (Wu ^* ) and the pulse width error prediction value (Wuep) as the pulse width prediction value (Wup). The subtracter (46) subtracts the predicted pulse width value (Wup) from the detected pulse width value (Wu) to obtain a pulse width error (Wue). The filter (52) smoothes the pulse width error (Wue) to obtain a smoothed pulse width error (Wuf). The adder (48) calculates the sum of the predicted pulse width (Wup) and the smoothed pulse width error (Wuf) as the corrected pulse width (Wua). The pulse width correction unit (40) in FIG. 4 performs the same processing for the v phase and the w phase.

As can be seen from FIG. 6, the error between the pulse width command value (Wu ^* ) and the pulse width detection value (Wu) varies greatly depending on the phase current output to the motor (4). However, in the pulse width correction unit (40), the pulse width error calculation unit (42) outputs an error corresponding to the phase current of the motor (4), and a pulse width predicted value (Wup) is generated based on the error. Therefore, the pulse width error (Wue) output from the subtractor (46) becomes a substantially constant value regardless of the phase current of the motor (4). It can be said that the value is an offset corresponding to the inverter (16). Since the pulse width error (Wue) is substantially constant, the filter (52) can easily smooth the pulse width error (We). Since the filter (52) is used, the influence of disturbance such as noise can be suppressed, and the corrected pulse width (Wua) can be obtained more accurately and stably. For this reason, even if it receives disturbance, the phase voltage supplied to the motor (4) from the inverter (16) and its time average can be obtained more accurately and stably. Therefore, the position of the rotor of the motor (4) can be estimated more accurately and the motor (4) can be driven. Further, since the predicted pulse width error value (Wuep) is used, the corrected pulse width (Wua) converges quickly.

  FIG. 7 is a block diagram showing another configuration example of the pulse width correction unit of FIG. The pulse width correction unit (240) of FIG. 7 differs from the pulse width correction unit (40) of FIG. 3 in that it further includes a register (54), a noise determination unit (56), and a switch (58). ing. Other points are the same as those of the pulse width correction unit (40) of FIG. The pulse width correction unit (240) further includes two configurations shown in FIG. 7, which perform processing for the v phase and the w phase, respectively.

  The register (54) stores and outputs the smoothed pulse width error (Wuf). However, the register (54) outputs the smoothed pulse width error (Wuf) obtained previously (for example, with respect to the previous pulse). The noise determination unit (56) compares the absolute value of the pulse width error (Wue) output from the subtracter (46) with a predetermined threshold value, and the absolute value of the pulse width error (Wue) is the threshold value. If larger than the value, a signal indicating that noise is detected is output. The switch (58) normally selects the smoothed pulse width error (Wuf) and outputs it to the adder (48), but the noise judgment unit (56) outputs a signal indicating that noise has been detected. If so, the output of the register (54) is selected and output. The pulse width correction unit (240) performs the same processing for the v phase and the w phase. According to the pulse width correction unit (240) of FIG. 7, when the noise is relatively large, the previously obtained value is selected, so that it is less susceptible to disturbance.

  FIG. 8 is a block diagram showing still another configuration example of the pulse width correction unit in FIG. The pulse width correction unit (340) of FIG. 8 differs from the pulse width correction unit (40) of FIG. 3 in that it further includes a sensor abnormality determination unit (62) and a switch (64). Other points are the same as those of the pulse width correction unit (40) of FIG. The pulse width correction unit (340) further includes two configurations shown in FIG. 8, which perform processing for the v-phase and the w-phase, respectively.

  When the sensor abnormality determination unit (62) detects that the absolute value of the pulse width error (Wue) for the same phase is larger than a predetermined value continuously for a predetermined number of times (over a predetermined number of pulses) The sensor that measures the voltage (Vu) of the phase is determined to have failed, and a signal indicating that the sensor has failed is output. The switch (64) normally selects the output signal (Wua0) of the adder (48), but when the sensor abnormality determination unit (62) outputs a signal indicating that the sensor has failed, A predicted pulse width (Wup) is selected, and the phase is output as a corrected pulse width (Wua). The pulse width correction unit (340) performs the same processing for the v phase and the w phase.

  According to the pulse width correction unit (340) of FIG. 8, it is possible to detect the failure of the sensor that measures the voltage (Vu, Vv, or Vw). If it is determined that the sensor has failed, the estimated pulse width (Wup, Wvp or Wwp) is used as the corrected pulse width (Wua, Wva or Wwa), so the voltage (Vu, Vv or Vw) It is not necessary to use the pulse width detection value (Wu, Wv or Ww) detected from the above, and the motor (4) can be continuously driven.

When the pulse width correction unit (40) in FIG. 4, the pulse width correction unit (240) in FIG. 7, and the pulse width correction unit (340) in FIG. 8 perform processing related to the v phase, the pulse width correction unit (40, 240, 340) ), Instead of the u-phase pulse width detection value (Wu), pulse width command value (Wu ^* ), and phase current detection value (Iu), the v-phase pulse width detection value (Wv), pulse width command value The corrected pulse width (Wva) is obtained by using (Wv ^* ) and the phase current detection value (Iv). Similarly, when performing processing related to the w phase, the pulse width correction unit (40, 240, 340) replaces the pulse width detection value (Wu), the pulse width command value (Wu ^* ), and the phase current detection value (Iu). The corrected pulse width (Wwa) is obtained by using the w-phase pulse width detection value (Ww), the pulse width command value (Ww ^* ), and the phase current detection value (Iw).

  When the phase current output to the motor (4) is smaller than the predetermined value, the pulse width correction unit (40) uses the pulse width detection value (Wu) as it is as the corrected pulse width (Wua). It may be used. In such a case, more specifically, for example, the pulse width error calculation unit (42) may set the output value to zero. When the phase current output to the motor (4) is small, the pulse width error is also small, so that the processing can be simplified.

  In each of the above examples, instead of the filter (52), the sum of a value proportional to the pulse width error (Wue, Wve or Wwe) and a value obtained by integrating the pulse width error (Wue, Wve or Wwe) is obtained. An output PI (proportional integral) control unit may be used.

  In each of the above examples, instead of the filter (52), an averaging unit that calculates and outputs an average value of pulse width errors (Wue, Wve, or Wwe) may be used. The average value may be an integral value per unit time or a moving average. Even if any of the filter (52), the PI control unit, and the averaging unit is used, the pulse width detection value (Wu, Wv, or Ww) can be corrected so that the influence of disturbance is reduced.

  Each functional block in this specification may typically be realized by hardware. For example, each functional block can be formed on a semiconductor substrate as part of an IC (integrated circuit). Here, the IC includes a large-scale integrated circuit (LSI), an application-specific integrated circuit (ASIC), a gate array, a field programmable gate array (FPGA), and the like. Alternatively, some or all of each functional block can be implemented in software. For example, such a functional block can be realized by a processor and a program executed on the processor. In other words, each functional block described in the present specification may be realized by hardware, may be realized by software, or may be realized by any combination of hardware and software.

  The many features and advantages of the present invention are apparent from the written description, and thus, it is intended by the appended claims to cover all such features and advantages of the invention. Further, since many changes and modifications will readily occur to those skilled in the art, the present invention should not be limited to the exact construction and operation as illustrated and described. Accordingly, all suitable modifications and equivalents are intended to be within the scope of the present invention.

  As described above, the present invention is useful for a motor control method, a motor control device, and the like that control a motor used in an air conditioner and other devices.

4 Motor
10 Motor controller
24 PWM signal generator
26 Position estimation part
32 Pulse width detector
34 Output voltage calculator
40, 240, 340 Pulse width correction section
42 Pulse width error calculator
44, 48 adder
46 Subtractor
52 Filter
C PWM signal
Iu, Iv, Iw phase current detection value
Vu, Vv, Vw phase voltage
Vua, Vva, Vwa Output voltage detection value
Wf Smoothed pulse width error
Wp Predicted pulse width
Wu, Wv, Ww Pulse width detection value
Wu ^* , Wv ^* , Ww ^* Pulse width command value
Wua, Wva, Wwa Corrected pulse width

Claims (8)

A motor control method for driving a motor (4) using a PWM signal (C),
The pulse width of the phase voltage (Vu, Vv or Vw) supplied to the motor (4) is detected as a pulse width detection value (Wu, Wv or Ww),
An error between a pulse width command value (Wu ^* , Wv ^* or Ww ^* ), which is a pulse width of the PWM signal (C), and the pulse width detection value (Wu, Wv or Ww) of the corresponding phase; The pulse width error prediction from the phase current detection value (Iu, Iv or Iw) of the motor (4) based on the relationship obtained in advance with the phase current of the corresponding phase of the motor (4) Find the value (Wuep, Wvep or Wwep)
The pulse width command value (Wu ^* , Wv ^* or Ww ^* ) is corrected using the pulse width error prediction value (Wuep, Wvep or Wwep) to obtain the pulse width prediction value (Wup, Wvp or Wwp). ,
The pulse width detection value (Wu, Wv or Ww) is corrected using the predicted pulse width value (Wup, Wvp or Wwp) so that the influence of disturbance is reduced, and the corrected pulse width (Wua , Wva or Wwa)
Using the corrected pulse width (Wua, Wva or Wwa), an output voltage detection value (Vua, Vva or Vwa) which is a time average of the phase voltage (Vu, Vv or Vw) is obtained.
The motor control method which estimates the position ((theta)) of the rotor of the said motor (4) using the said output voltage detection value (Vua, Vva, or Vwa). The motor control method according to claim 1,
When the phase current detection value (Iu, Iv or Iw) of the motor (4) is smaller than a predetermined value, the pulse width detection value (Wu, Wv or Ww) is changed to the corrected pulse width (Wua, Motor control method used as Wva or Wwa). In the motor control method according to claim 1 or 2,
The difference between the pulse width prediction value (Wup, Wvp or Wwp) and the pulse width detection value (Wu, Wv or Ww) is obtained as a pulse width error (Wue, Wve or Wwe),
Smoothing the pulse width error (Wue, Wve or Wwe) to obtain a smoothed pulse width error (Wuf, Wvf or Wwf);
Motor control for obtaining a sum of the predicted pulse width value (Wup, Wvp or Wwp) and the smoothed pulse width error (Wuf, Wvf or Wwf) as the corrected pulse width (Wua, Wva or Wwa) Method. The motor control method according to claim 3,
A motor control method using the smoothed pulse width error (Wuf, Wvf or Wwf) obtained previously when the absolute value of the pulse width error (Wue, Wve or Wwe) is larger than a predetermined value. The motor control method according to claim 3,
When it is detected for a predetermined number of times that the absolute value of the pulse width error (Wue, Wve or Wwe) for the same phase is larger than a predetermined value, the phase voltage (Vu, A motor control method for determining that a sensor for measuring Vv or Vw) has failed. The motor control method according to claim 5, wherein
When it is determined that the sensor has failed, the motor control method using the pulse width predicted value (Wup, Wvp or Wwp) as the corrected pulse width (Wua, Wva or Wwa) for the same phase . The motor control method according to claim 1,
The previously obtained relationship is stored as an equation, and based on the equation, the error corresponding to the phase current detection value (Iu, Iv or Iw) of the motor (4) is converted into the pulse width error predicted value ( Motor control method to calculate as Wuep, Wvep or Wwep). A motor control device for driving a motor (4) using a PWM signal (C),
A pulse width detector (32) for detecting a pulse width of a phase voltage (Vu, Vv or Vw) supplied to the motor (4) as a pulse width detection value (Wu, Wv or Ww);
An error between a pulse width command value (Wu ^* , Wv ^* or Ww ^* ), which is a pulse width of the PWM signal (C), and the pulse width detection value (Wu, Wv or Ww) of the corresponding phase; The pulse width error prediction from the phase current detection value (Iu, Iv or Iw) of the motor (4) based on the relationship obtained in advance with the phase current of the corresponding phase of the motor (4) A value (Wuep, Wvep or Wwep) is obtained, the pulse width command value (Wu ^* , Wv ^* or Ww ^* ) is corrected using the predicted pulse width error value (Wuep, Wvep or Wwep), and the pulse width is corrected. The predicted value (Wup, Wvp or Wwp) is obtained, and the influence of the disturbance is reduced by using the pulse width detection value (Wu, Wvp or Wwp) as the pulse width detection value (Wup, Wvp or Wwp). A pulse width correction unit (40; 240; 340) for obtaining a corrected pulse width (Wua, Wva or Wwa),
An output voltage calculation unit (34) that obtains an output voltage detection value (Vua, Vva, or Vwa) that is a time average of the phase voltage (Vu, Vv, or Vw) by using the corrected pulse width (Wua, Wva, or Wwa). )When,
A motor control device comprising: a position estimation unit (26) that estimates a rotor position (θ) of the motor (4) using the output voltage detection value (Vua, Vva, or Vwa).

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