JP2008206383A - Control device of multi-phase rotary electric machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device of multi-phase rotary electric machine that can suitably suppress torque variations associated with switching from rectangular wave control to voltage control when performing voltage control to control a voltage applied to each phase of a multi-phase rotary electric machine to its command value, and a rectangular wave control. <P>SOLUTION: In a control device of multi-phase rotary electric machine as shown in Fig. 9 (d) when performing rectangular wave control, actual voltage vector Vr usually differs from a voltage vector Ve for generating a currently generated output torque by PWM control. During rectangular wave control, the voltage vector Ve is calculated one after another, and when this is equal to or less than a limit voltage VL, a control mode switches from rectangular wave control to PWM control. Here, the limit voltage VL is determined by an input voltage of an inverter. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a control device for a multiphase rotating machine that controls an output of the multiphase rotating machine by operating a switching element of an inverter that supplies electric power to the multiphase rotating machine.

  As this type of control device, a command value (command voltage) of a voltage to be applied to each phase is calculated in order to control the current flowing in each phase of the three-phase motor as desired, and the calculated command voltage and carrier There is also proposed one that performs PWM control for operating the switching element of the inverter based on the size of the inverter. Thereby, the voltage applied to each phase of the three-phase motor can be used as a command voltage, and the current flowing through each phase can be controlled as desired.

In addition, in the high-speed rotation region of the three-phase motor, so-called rectangular wave control is performed in which the ON / OFF cycle of the switching element of the inverter substantially matches the rotation cycle of the electrical angle of the three-phase motor (Patent Documents 1 to 3). ).
JP 2000-50689 A JP 2004-282803 A JP 2004-72954 A

  However, when the rectangular wave control is performed in the high rotation speed region and the PWM control is performed in other regions, the torque may change abruptly when switching from the rectangular wave control to the PWM control.

  Note that the present invention is not limited to the above-described rectangular wave control and PWM control, but is applicable to a voltage control that controls the voltage applied to each phase of the multiphase rotating machine to its command value and a control device that performs the rectangular wave control. Thus, such a situation where torque fluctuation may occur in accordance with switching between the rectangular wave control and the voltage control is generally common.

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to perform voltage control for controlling the voltage applied to each phase of the multiphase rotating machine to its command value and rectangular wave control. At the time, an object of the present invention is to provide a control device for a multi-phase rotating machine capable of suitably suppressing torque fluctuations associated with switching between rectangular wave control and voltage control.

  Hereinafter, means for solving the above-described problems and the operation and effects thereof will be described.

  According to a first aspect of the present invention, a rectangular wave that operates the switching element so as to make the period of change in the voltage applied to each phase of the multiphase rotating machine substantially coincide with the rotation period of the electrical angle of the multiphase rotating machine. When the control means, the voltage control means for operating the switching element to control the voltage applied to each phase of the multiphase rotating machine to its command value, and the control by the rectangular wave control means, the control And an estimation means for estimating a parameter value relating to a voltage required as the command value when the output torque generated by the voltage control means is generated by the voltage control means.

  The controllability of the voltage control means depends on the maximum value of the command value. This is because the maximum value of the voltage that can be applied to each phase of the multiphase rotating machine is about the input voltage to the inverter. Here, in the above invention, when the rectangular wave control is performed, a parameter relating to a voltage required for realizing the output torque generated by the control by the voltage control means is estimated. For this reason, when the control by the rectangular wave control means is performed, the controllability when the control is performed by the voltage control means can be grasped. For this reason, it is possible to determine whether or not the torque fluctuation that can be caused by switching between the rectangular wave control means and the voltage control means can be suitably suppressed.

  In addition to the voltage itself, for example, in the case of a three-phase rotating machine, the parameters include the length of the voltage on the dq axis, the d-axis component of the voltage on the dq axis, and the voltage vector on the dq axis. There is a phase.

  The invention according to claim 2 is the invention according to claim 1, wherein the estimation means estimates the parameter based on a model including a d-axis inductance and a q-axis inductance of the multiphase rotating machine, and The d-axis inductance is a constant, and the q-axis inductance is variably set according to a current flowing through the multiphase rotating machine.

  The inductance component of the multiphase rotating machine varies depending on the temperature of the multiphase rotating machine and the current flowing through the multiphase rotating machine. For this reason, since the estimation by the estimation means is affected by this change, when estimation is performed assuming that these inductance components are constant, an error occurs in the estimation.

  Here, under the above assumption, the inventor has found that the fluctuation of the q-axis inductance component has a large influence on the estimation, while the fluctuation of the d-axis inductance component has a small influence on the estimation. . In the above-mentioned invention, paying attention to this point, the above estimation can be performed with high accuracy by variably setting the q-axis inductance component according to the current flowing through the multiphase rotating machine that causes the q-axis inductance component to change. it can.

  According to a third aspect of the present invention, in the second aspect of the present invention, the estimation error of the estimation means is applied to the multiphase rotating machine by the voltage control means when being controlled by the voltage control means. It further comprises error learning means for learning based on a parameter value relating to voltage and a value estimated by the estimation means.

  When estimating the parameter relating to the voltage based on the model, the q-axis inductance is variably set based on the current flowing through the multiphase rotating machine, so that the fluctuation of the estimated value due to the fluctuation of the parameters constituting the model can be suitably compensated. However, the absolute value of the estimated value cannot be set with high accuracy only by the variable setting of the q-axis inductance. In this regard, in the above invention, when the control by the voltage control means is performed, based on the value of the parameter relating to the voltage applied to the multiphase rotating machine by the voltage control means and the estimated value, The model error at an arbitrary operating point of the rotating machine can be learned with high accuracy. Then, it is possible to estimate with high accuracy by preferably compensating the influence of the change of the parameter of the model with respect to the change from the operating point by the variable setting of the q-axis inductance.

  According to a fourth aspect of the present invention, in the third aspect of the present invention, the error learning means is a parameter relating to a voltage applied to the multiphase rotating machine when a rotational speed of the multiphase rotating machine is equal to or higher than a predetermined value. Based on this, the learning is performed.

  The fluctuation of the q-axis inductance is particularly noticeable in the high rotation speed region of the multiphase rotating machine as a factor of the fluctuation of the estimated value of the parameter relating to the voltage using the model. In the above invention, paying attention to this point, when the variation of the estimated value due to the variation of the model parameter can be suitably compensated only by variably setting the q-axis inductance, that is, the rotational speed of the multiphase rotating machine is not less than a predetermined value. At some point, learn. Thereby, the above estimation can be performed with higher accuracy by the cooperation of the variable setting of the q-axis inductance and the learning result.

  According to a fifth aspect of the present invention, in the first aspect of the invention, the estimation error of the parameter estimated by the estimation means is controlled by the voltage control means when the polyphase rotation is controlled by the voltage control means. The apparatus further comprises error learning means for learning based on a parameter value relating to a voltage applied to the machine and a value estimated by the estimating means.

  Since the resistance component and the inductance component of the multiphase rotating machine change according to the temperature of the multiphase rotating machine and the current flowing through the multiphase rotating machine, the estimation by the estimating means is affected by this change. In this regard, in the above-described invention, by including the error learning means, it is possible to preferably learn the estimation error caused by the change in the model parameter.

  According to a sixth aspect of the present invention, in the invention according to any one of the third to fifth aspects, the maximum value of the required voltage is based on the learning result by the error learning unit and the estimation by the estimation unit. When it is determined that the voltage is equal to or lower than the predetermined voltage, the apparatus further includes switching means for switching to control by the voltage control means.

  In the above-described invention, it is possible to quantify whether or not the torque fluctuation associated with the switching from the rectangular wave control means to the voltage control means can be suitably suppressed by the predetermined voltage. Then, by performing switching based on this predetermined voltage, it is possible to suitably suppress torque fluctuations associated with switching from rectangular wave control to voltage control. Further, when determining whether or not the voltage is equal to or lower than the predetermined voltage, the use of the learning result of the error learning unit as well as the estimation unit makes a highly accurate determination while preferably compensating for the influence of the estimation error by the estimation unit. be able to.

  According to a seventh aspect of the present invention, in the sixth aspect of the invention, the error learning unit learns an estimated value of the estimating unit when switching from the control of the voltage control unit to the control of the rectangular wave control unit. The switching means determines whether the maximum value of the required voltage is equal to or lower than a predetermined voltage by comparing a value estimated by the estimating means with a threshold value. In addition, the threshold value is set based on a value learned by the error learning unit, a value at the time of learning by the error learning unit, and a current value for the input voltage of the inverter.

  When the voltage applied to the multiphase rotating machine becomes equal to or higher than a predetermined voltage by the control by the voltage control means, the controllability is lowered. For this reason, when the applied voltage is equal to or higher than the predetermined voltage, switching to control by the rectangular wave control means is usually performed. For this reason, it is considered that the estimated value of the estimation means at the time of switching, that is, the value learned by the error learning means can be used as a threshold for switching from control by the rectangular wave control means to control by the voltage control means. . However, when the input voltage of the inverter fluctuates, a predetermined voltage suitable for switching between control by the rectangular wave control means and control by the voltage control means changes. In the above invention, paying attention to this point, the threshold value is set based on the value learned by the learning means and the learning value by the error learning means and the current value for the input voltage of the inverter. It is possible to appropriately determine whether or not the voltage applied to the multiphase rotating machine has become equal to or lower than a predetermined voltage.

  The invention according to claim 8 is the invention according to claim 1, wherein the voltage control means controls the voltage applied to each phase to the command value in order to use the current flowing through the multi-phase rotating machine as its command value. And determining means for determining whether or not the current flowing through the multi-phase rotating machine falls within a region in the vicinity of the command value of the current when control by the rectangular wave control means is performed; and Switching means for switching to the control by the voltage control means based on the amount of change in the estimated value by the estimation means after it is determined that it falls within the region in the vicinity of the command value.

  The resistance component and the inductance component of the multiphase rotating machine change depending on the temperature of the multiphase rotating machine, a magnetic field generated by a current flowing through the multiphase rotating machine, and the like. For this reason, since the estimation by the estimation means is affected by this change, an error occurs in the estimation when the estimation is performed assuming that the resistance component, the inductance component, and the like are constant.

  Here, in the above-described invention, it is determined whether or not the current flowing through the multiphase rotating machine enters a region in the vicinity of the current command value by the voltage control means. In this determination, since the estimated value of the voltage is not used, this determination can be made with high accuracy without being affected by the change. On the other hand, when the output torque generated during the rectangular wave control is generated by the voltage control means after entering the region, the voltage required for the voltage control means can maintain the controllability of the voltage control means high. Changes in the resistance component and the inductance component of the multiphase rotating machine during the period until reaching the value are small. For this reason, it is considered that the amount of change in the voltage vector during this period is uniquely determined according to the region. In the above invention, paying attention to this point, when the output torque generated by the rectangular wave control is generated by the voltage control means, the voltage required for the voltage control means maintains the controllability of the voltage control means high. It is possible to determine with high accuracy whether or not the value can be obtained, and thus, it is possible to suitably suppress the torque fluctuation that may be caused by switching between the voltage control unit and the rectangular wave control unit.

  It should be noted that “whether or not the current flowing through the multiphase rotating machine falls within the region near the current command value” indicates that the tip of the actual current vector on the dq axis is on the dq axis in the three-phase rotating machine. It is desirable to determine whether or not to enter a region near the command value.

  According to a ninth aspect of the present invention, in the first aspect of the invention, the switching means for switching to the control by the voltage control means when the maximum value of the required voltage is not more than a predetermined voltage based on the estimation by the estimation means. Is further provided.

  In the above-described invention, it is possible to quantify whether or not the torque fluctuation associated with the switching from the rectangular wave control means to the voltage control means can be suitably suppressed by the predetermined voltage. Then, by performing switching based on this predetermined voltage, it is possible to suitably suppress torque fluctuations associated with switching from rectangular wave control to voltage control.

  According to a tenth aspect of the present invention, in the first or ninth aspect of the invention, the estimation means includes a detected value of a rotational speed of the multiphase rotating machine, a detected value of a current flowing through the multiphase rotating machine, and the parameter. It is characterized by having a map that defines the relationship of

  The resistance component and the inductance component of the multiphase rotating machine change depending on the temperature of the multiphase rotating machine, a magnetic field generated by a current flowing through the multiphase rotating machine, and the like. For this reason, since the estimation by the estimation means is affected by this change, an error occurs in the estimation when the estimation is performed assuming that the resistance component, the inductance component, and the like are constant.

  In this regard, in the above invention, since the value of the parameter is estimated using the map, an estimated value reflecting the change can be calculated, and the estimation accuracy of the parameter value can be improved.

  According to an eleventh aspect of the present invention, in the invention according to the tenth aspect, the map includes a detected value of a rotational speed of the multiphase rotating machine, a detected value of a current flowing through the multiphase rotating machine, and the multiphase rotating machine. The relationship between the temperature and the parameter is defined.

  In the above invention, in addition to the detected value of the rotational speed of the multiphase rotating machine and the detected value of the current flowing through the multiphase rotating machine, the estimated value reflecting the change is obtained by using the temperature of the multiphase rotating machine. It is possible to calculate with higher accuracy, and as a result, it is possible to further improve the estimation accuracy of the parameter value.

  According to a twelfth aspect of the present invention, there is provided a rectangular wave that operates the switching element so as to make the period of change in voltage applied to each phase of the multiphase rotating machine substantially coincide with the rotation period of the electrical angle of the multiphase rotating machine. When the control means, the voltage control means for operating the switching element to control the voltage applied to each phase of the multiphase rotating machine to its command value, and the control by the rectangular wave control means, the control Estimating the parameter relating to the voltage required as the command value when the output torque generated by the voltage control means is generated, and based on the estimated value of the estimating means, the maximum of the required voltage Based on the estimated value, switching means for switching to control by the voltage control means when the value is equal to or lower than a predetermined voltage for switching to control by the voltage control means The information about the timing of the serial switching, characterized in that it comprises a suppression means for suppressing the error according to at least one of change in the resistance component and the inductance component of the multi-phase rotary machine.

  The controllability of the voltage control means depends on the maximum value of the command value. This is because the maximum value of the voltage that can be applied to each phase of the multiphase rotating machine is about the input voltage to the inverter. Here, in the above invention, when the rectangular wave control is performed, a parameter relating to a voltage required for realizing the output torque generated by the control by the voltage control means is estimated. For this reason, when the control by the rectangular wave control means is performed, the controllability when the control is performed by the voltage control means can be grasped. For this reason, it is possible to determine whether or not the torque fluctuation that can be caused by switching between the rectangular wave control means and the voltage control means can be suitably suppressed.

  By the way, the resistance component and the inductance component of the multiphase rotating machine vary depending on the temperature of the multiphase rotating machine, the magnetic field generated by the current flowing through the multiphase rotating machine, and the like. For this reason, since the estimation by the estimation means is affected by this change, an error occurs in the estimation when the estimation is performed assuming that the resistance component, the inductance component, and the like are constant. For this reason, an error occurs in the switching timing based on the estimated value. In this regard, in the above invention, such a situation can be suitably coped with by including suppression means for suppressing an error due to a change in at least one of the resistance component and the inductance component.

  In addition to the voltage itself, for example, in the case of a three-phase rotating machine, the parameters include the length of the voltage on the dq axis, the d-axis component of the voltage on the dq axis, and the voltage vector on the dq axis. There is a phase.

  According to a thirteenth aspect of the present invention, in the twelfth aspect of the present invention, the voltage control means controls the voltage applied to each phase to a command value so that the current flowing through the multiphase rotating machine is a command value. The suppression means is means for determining whether or not the current flowing through the multiphase rotating machine falls within a region near the command value of the current when the control by the rectangular wave control means is performed. And the maximum value of the required voltage is switched to the control by the voltage control means based on the amount of change in the estimated value by the estimation means since it is determined that the current value falls within the region near the command value. And a means for determining when the voltage is equal to or lower than a predetermined voltage.

  In the said invention, it is judged whether the electric current which flows through a multiphase rotary machine enters the area | region of the vicinity of the command value of the electric current by the said voltage control means. In this determination, since the estimated value of the voltage is not used, this determination can be made with high accuracy without being affected by the change in the resistance value and the inductance. On the other hand, when the output torque generated during the rectangular wave control is generated by the voltage control means after entering the region, the voltage required for the voltage control means can maintain the controllability of the voltage control means high. Changes in the resistance component and the inductance component of the multiphase rotating machine during the period until reaching the value are small. For this reason, it is considered that the amount of change in the voltage vector during this period is uniquely determined according to the region. In the above invention, paying attention to this point, when the output torque generated by the rectangular wave control is generated by the voltage control means, the voltage required for the voltage control means maintains the controllability of the voltage control means high. It is possible to determine with high accuracy whether or not the value can be achieved, and thus it is possible to favorably suppress torque fluctuations that can be caused by switching to the voltage control means.

  It should be noted that “whether or not the current flowing through the multiphase rotating machine falls within the region near the current command value” indicates that the tip of the actual current vector on the dq axis is on the dq axis in the three-phase rotating machine. It is desirable to determine whether or not to enter a region near the command value.

  According to a fourteenth aspect of the present invention, in the twelfth aspect of the present invention, the suppression means includes a detection value of a rotation speed of the multiphase rotating machine and a detection value of a current flowing through the multiphase rotating machine. It is realized by comprising a map that defines the relationship with the parameter.

  In the above invention, in order to estimate the value of the parameter using the map, it is possible to calculate an estimated value reflecting a change in the inductance or the like, and to improve the estimation accuracy of the parameter value.

  The invention according to a fifteenth aspect is the invention according to the fourteenth aspect, wherein the map includes a detected value of a rotational speed of the multiphase rotating machine, a detected value of a current flowing through the multiphase rotating machine, and the multiphase rotating machine. The relationship between the temperature and the parameter is defined.

  In the above invention, in addition to the detected value of the rotational speed of the multiphase rotating machine and the detected value of the current flowing through the multiphase rotating machine, the temperature of the multiphase rotating machine is used to reflect changes in the inductance and the like. The estimated value can be calculated with higher accuracy, and as a result, the estimated accuracy of the parameter value can be further improved.

  According to a sixteenth aspect of the present invention, there is provided a rectangular wave for operating the switching element so as to make the period of change in the voltage applied to each phase of the multiphase rotating machine substantially coincide with the rotation period of the electrical angle of the multiphase rotating machine. When the control means, the voltage control means for operating the switching element to control the voltage applied to each phase of the multiphase rotating machine to its command value, and the control by the rectangular wave control means, the control And an estimation means for estimating either the voltage required as the command value or an equivalent value when the output torque generated by the voltage control means is generated by the voltage control means.

  The controllability of the voltage control means depends on the maximum value of the command value. This is because the maximum value of the voltage that can be applied to each phase of the multiphase rotating machine is about the input voltage to the inverter. Here, in the above configuration, when the rectangular wave control is performed, either the voltage required to realize the output torque generated by the control by the voltage control unit or an equivalent value thereof is estimated. For this reason, when the control by the rectangular wave control means is performed, the controllability when the control is performed by the voltage control means can be grasped. For this reason, it can be determined whether or not the torque fluctuation that can be caused by switching from the rectangular wave control means to the voltage control means can be suitably suppressed.

  The invention according to claim 17 is the switching means for switching to the control by the voltage control means when the maximum value of the required voltage is not more than a predetermined voltage based on the estimation by the estimation means in the invention of claim 16. It is characterized by providing.

  In the above-described configuration, it is possible to quantify whether or not the torque fluctuation associated with the switching from the rectangular wave control means to the voltage control means can be suitably suppressed by the predetermined voltage. Then, by performing switching based on this predetermined voltage, it is possible to suitably suppress torque fluctuations associated with switching from rectangular wave control to voltage control.

  The invention described in claim 18 is the invention described in claim 6, 7, 9 or 12-15, 17, wherein the predetermined voltage is a value that is "1.28 × 1/2" times the input voltage to the inverter. It is characterized by being set as follows.

  It is well known that the maximum value of the command value that can maintain the controllability of the voltage control means is theoretically a value that is “1.28 × ½” times the input voltage of the inverter. That is, when the command value is larger than this, the controllability that makes the multi-phase rotating machine a desired output is lowered by the voltage control means. In this regard, in the above configuration, the predetermined voltage is set to be equal to or lower than the maximum value that can maintain high controllability by the voltage control unit, so that the voltage control unit can be switched from the rectangular wave control unit to the voltage control unit. High controllability can be maintained. For this reason, at the time of switching from the rectangular wave control means to the voltage control means, it is possible to suitably perform control for suppressing a change from the output torque generated by the rectangular wave control means.

  Further, as an invention having an object similar to that of the invention described in claim 18, in the invention described in claim 6, 7, 9 or 12 to 15, 17, the predetermined voltage is “1.27 of an input voltage to the inverter. It may be characterized in that it is set to a value not more than × 1/2 ”.

  According to a nineteenth aspect of the present invention, in the invention according to any one of the first to ninth, twelfth, thirteenth, and sixteenth to eighteenth aspects, the estimation means includes: a required torque for the multiphase rotating machine; The estimation is performed based on the rotational speed of the output shaft of the machine.

  When the control by the rectangular wave control means is performed, if this control is performed normally, the output torque of the multiphase rotating machine is considered to approximate the required torque. In this regard, in the above-described invention, the value of “the output torque generated by the rectangular wave control means” can be easily obtained by using the required torque.

  According to a twentieth aspect of the present invention, in the invention according to the nineteenth aspect, the estimation unit generates the required torque as the output torque generated by the rectangular wave control unit under the control of the voltage control unit. Detecting the rotational speed using a means for estimating either a current flowing through each phase of the multiphase rotating machine or an equivalent value thereof, and a parameter relating to a voltage required as a command value of the voltage control means for flowing the current And a means for estimating based on the value.

  If the output torque generated by the rectangular wave control is known, the current flowing through the multiphase rotating machine can be estimated when the output torque is generated by the voltage control means. And the parameter regarding the voltage (voltage command value) applied to a multiphase rotating machine in order to flow this electric current is decided by the above-mentioned electric current and rotation speed. Therefore, in the above invention, when the control by the rectangular wave control means is performed, the parameter relating to the voltage required as the command value when the output torque generated by the control is generated by the voltage control means can be estimated. it can.

  According to a twenty-first aspect of the invention, in the invention according to any one of the first to ninth, twelfth, thirteenth, and sixteenth to eighteenth aspects, the estimation means includes a detected value of a current flowing through the multiphase rotating machine, and the The estimation is performed based on the rotational speed of the output shaft of the multiphase rotating machine.

  The command value of the voltage required for generating an arbitrary output torque by the voltage control means depends on the rotational speed. On the other hand, the output torque generated by the control by the rectangular wave control means can be estimated by the current flowing through the multiphase rotating machine. In this regard, in the above configuration, the voltage required when the output torque generated by the rectangular wave control is generated by the voltage control means is preferably estimated based on the detected value of the rotational speed and the detected value of the current. Can do.

  According to a twenty-second aspect of the present invention, in the twenty-first aspect, the estimating means estimates the output torque of the multiphase rotating machine based on the detected value of the current, and the output torque is the voltage control means. Means for estimating either the current flowing through each phase of the multi-phase rotating machine or its equivalent value when generated by the control of, and the voltage applied to each phase of the multi-phase rotating machine to flow the current And a means for estimating one of the corresponding values based on the detected value of the rotation speed.

  The detected value of the current flowing through the multiphase rotating machine is a parameter having a correlation with the output torque of the multiphase rotating machine. In the above configuration, in view of this point, the output torque is estimated based on the detected current value. If the output torque generated by the rectangular wave control is known, the current flowing through the multiphase rotating machine can be estimated when the output torque is generated by the voltage control means. The voltage applied to the multi-phase rotating machine to flow this current, in other words, the voltage command value is determined by the current and the rotational speed. For this reason, in the above configuration, when the control by the rectangular wave control means is performed, either the voltage required as the command value or the equivalent value is required when the output torque generated by the control is generated by the voltage control means. Can be estimated.

  The invention according to claim 23 is the invention according to any one of claims 1 to 22, wherein the multi-phase rotating machine is a three-phase rotating machine, and the estimating means includes a parameter relating to the required voltage or A voltage on the dq axis as an equivalent value of the required voltage is estimated.

  In the above configuration, the voltage on the dq axis is estimated as an equivalent value of the required voltage, so that switching from the rectangular wave control means to the voltage control means can be performed based on the DC voltage. For this reason, since it is not necessary to consider the amplitude of a voltage, the process concerning switching can be performed simply.

  According to a twenty-fourth aspect of the invention, in the invention according to any one of the first to twenty-third aspects, a maximum value of the command value by the voltage control means is “1.28 × 1 / of an input voltage to the inverter. When the value is 2 times or more, the control by the voltage control unit is switched to the control by the rectangular wave control unit.

  It is well known that the critical value for the command value in the control by the voltage control means is a value “1.28 × ½” times the input voltage of the inverter. That is, when the command value is larger than this, the controllability that makes the output of the multiphase rotating machine a desired output by the voltage control means decreases. In this regard, in the above configuration, when the command value is equal to or greater than the above value, switching to rectangular wave control allows the output torque of the multiphase rotating machine to be controlled even in a region where the command value by the voltage control means is equal to or greater than the above value. High controllability can be maintained.

  According to a twenty-fifth aspect of the present invention, there is provided a rectangular wave for operating the switching element so as to make the period of change in voltage applied to each phase of the multiphase rotating machine substantially coincide with the rotation period of the electrical angle of the multiphase rotating machine. Control means, voltage control means for operating the switching element to control the voltage applied to each phase of the multiphase rotating machine to its command value, and a detected value of the current flowing through each phase of the multiphase rotating machine And switching means for switching from control by the rectangular wave control means to control by the voltage control means based on the detected value of the rotational speed of the output shaft of the multiphase rotating machine.

  The detected value of the current flowing through each phase of the multiphase rotating machine has a correlation with the output torque of the multiphase rotating machine. For this reason, by switching from the rectangular wave control means to the voltage control means based on the detected current value, fluctuations in the output torque can be suppressed during the switching. In addition, by switching using the detected value of the rotational speed, it is in a high rotational speed region that should be controlled by the rectangular wave control means, or the rotational speed is shifted to an appropriate region controlled by the voltage control means. You can also determine whether you are doing it. Moreover, by having the structure of the following Claim 18, it can also be judged whether it is an area | region which can maintain the controllability of a voltage control means highly. For this reason, it is possible to perform switching to the voltage control means while suppressing fluctuations in the output torque in a region where the control by the voltage control means is appropriate.

  In the invention of claim 26, in the invention of claim 25, the switching means is required as the command value when the output torque generated by the control by the rectangular wave control means is generated by the voltage control means. The switching is performed when the maximum value of the applied voltage is equal to or lower than a predetermined voltage.

(First embodiment)
Hereinafter, a first embodiment in which a control device for a multiphase rotating machine according to the present invention is applied to a control device for a three-phase motor mounted in a hybrid vehicle will be described with reference to the drawings.

  In FIG. 1, the whole structure of the control system of the electric motor 4 is shown.

  The illustrated electric motor 4 is composed of an embedded magnet synchronous motor (IPMSM). In addition, an inverter 10 is connected to the three phases (U phase, V phase, and W phase) of the electric motor 4. This inverter 10 is a three-phase inverter, and includes switching elements 12, 14, switching elements 16, 18, and switching elements 20, 22 to connect each of the three phases to the positive side or negative side of the battery 42. It is configured with a parallel connection. Furthermore, the inverter 10 includes flywheel diodes 24 to 34 connected in antiparallel to the switching elements 12 to 22. A connection point for connecting the switching element 12 and the switching element 14 in series is connected to the U phase of the electric motor 4. A connection point for connecting the switching element 16 and the switching element 18 in series is connected to the V phase of the motor 4. Furthermore, a connection point for connecting the switching element 20 and the switching element 22 in series is connected to the W phase of the electric motor 4. Incidentally, these switching elements 12-22 are comprised by the insulated gate bipolar transistor (IGBT) in this embodiment.

  A smoothing capacitor 40 is connected to both ends of each pair of switching elements 12 and 14, switching elements 16 and 18, and switching elements 20 and 22 of the inverter 10.

  On the other hand, the microcomputer 50 includes a voltage sensor 44 that detects the voltage VB across the battery 42, a position sensor 52 that detects the rotation angle of the output shaft of the electric motor 4, and a current sensor that detects current flowing in the U phase and V phase. The output of 54 and 56 is taken in. The microcomputer 50 calculates the current flowing in the W phase from the current iu flowing in the U phase and the current iv flowing in the V phase based on Kirchhoff's law. The microcomputer 50 operates the switching elements 12 to 22 via the gate drive circuits 60 to 70 based on the rotation angle of the output shaft of the electric motor 4 and the currents flowing through the three phases.

  FIG. 2 shows a block diagram of processing performed by the microcomputer 50. In the present embodiment, the output torque of the electric motor 4 is controlled to the required torque by triangular wave PWM control and rectangular wave control. In the following, the processing shown in FIG. 2 will be described in the order of processing related to triangular wave PWM control, processing related to rectangular wave control, and processing related to switching between these two controls.

<PWM control>
The three-phase / two-phase conversion unit 80 includes an actual current iu flowing through the U phase and an actual current iv flowing through the V phase detected by the current sensors 54 and 56, and an actual current iw flowing through the W phase calculated based on these. Is a part for generating a real current id and a real current iq by converting the coordinates to the dq axis. Incidentally, since the rotation angle of the electric motor 4 is used for the coordinate conversion, the rotation angle θ detected by the position sensor 52 is input to the three-phase / two-phase conversion unit 80. On the other hand, the command current generator 82 is a part that generates command currents iqc and idc in accordance with the required torque Tc. These command currents iqc and idc are current command values on the dq axis.

  Based on the difference between the command current idc and the actual current id, the PI control unit 84 calculates a proportional term and an integral term. The sum of these calculated values is output from the PI controller 84 as the first command voltage vd1. Further, based on the difference between the command current iqc and the actual current iq, the proportional term and the integral term are calculated by the PI control unit 86. The sum of these calculated values is output by the PI controller 86 as the first command voltage vq1. Here, the behavior of the first command voltages vd1 and vq1 will be described.

Voltages vu, vv, vw applied to each of the three phases, currents iu, iv, iw flowing through the three phases, and counter electromotive forces eu, ev, ew generated in the three phases, respectively, and the resistance R of the motor 4 The relationship between the self-inductance L ′, the mutual inductance M, and the time differential operator P is as follows.

vu = (R + PL ′) × iu−1 / 2 × PM × iv−1 / 2 × PM × iw + eu
vv = -1 / 2 * PM * iu + (R + PL ') * iv-1 / 2 * PM * iw + ev
vw = −1 / 2 × PM × iu −1 / 2 × PM × iv + (R + PL ′) × iw + ew

Here, when dq-axis conversion is performed, the voltages vd and vq of the d-axis and the q-axis are represented by the rotation speed ω of the electrical angle, the inductance Ld on the d-axis, the inductance Lq on the q-axis, and the counter electromotive force ωφ. The following formulas (cd) and (cq) are obtained. Note that the rotation speed of the electrical angle is a value obtained by multiplying the rotation speed of the electric motor 4 by the number of pole pairs of the electric motor 4.

vd = (R + PLd) × id−ωLq × iq (cd)
vq = ωLd × id + (R + PLq) × iq + ωφ (cq)

As shown in the above formulas (cd) and (cq), each axis component of the voltage applied to the motor 4 is not only a term proportional to the same axis component of the current flowing through the motor 4, but also different axes. It includes terms proportional to the components and back electromotive force ωφ (hereinafter referred to as interference terms).

  Therefore, in the present embodiment, the non-interacting control unit 88 calculates these interference terms based on the actual current id and the actual current iq to calculate the zeroth command voltages vd0 and vq0. Then, the d-axis command voltage vdc1 is calculated as the sum of the first command voltage vd1 and the zeroth command voltage vd0, and the q-axis command voltage vqc1 is calculated as the sum of the first command voltage vq1 and the zeroth command voltage vq0. To do.

  The d-axis command voltage vdc1 and the q-axis command voltage vqc1 are taken into the two-phase / three-phase converter 92. The two-phase / three-phase converter 92 converts the d-axis command voltage vdc1 and the q-axis command voltage vqc1 into a U-phase command voltage vuc1, a V-phase command voltage vvc1, and a W-phase command voltage vwc1. To do. These command voltages vuc 1, vvc 1, vwc 1 are voltages to be applied to each phase when a command current is passed through each phase of the electric motor 4. These command voltages vuc1, vvc1, and vwc1 are basically sine waves and the centers of the voltages are zero. However, when the modulation rate of the command voltages vuc1, vvc1, and vwc1 is large based on the voltage of the battery 42 detected by the voltage sensor 44, the final command voltage vuc1, vvc1 is obtained by superimposing a predetermined harmonic on the sine wave. , Vwc1. The command current of each phase of the electric motor 4 means a command current in each of the three phases determined by the command currents idc and iqc.

  These command voltages vuc1, vvc1, and vwc1 are applied to the non-inverting input terminals of the comparators 94, 96, and 98, respectively. Comparators 94, 96, and 98 compare the command voltages vuc 1, vvc 1, and vwc 1 with the triangular carrier wave generated by the triangular wave generator 100. The output signals gu1, gv1, and gw1 of the comparators 94, 96, and 98 are obtained by pulse width modulation (PWM) of the command voltages vuc1, vvc1, and vwc1, respectively.

  The output signals gu1, gv1, and gw1 are taken into the switching unit 102. Then, a signal output from the switching unit 102 and an inverted signal thereof by the inverters 104, 106, and 108 are taken into the deadtime generation unit 110. The Deadtime generating unit 110 shapes the waveform of each of the output signals and the inverted signal corresponding to the signals so as to avoid the overlapping of the timings of the edge portions. The waveform-shaped signal includes an operation signal gup for operating the U-phase switching element 12, an operation signal gun for operating the U-phase switching element 14, and an operation signal gvp for operating the V-phase switching element 16, V-phase. The operation signal gvn for operating the switching element 18, the operation signal gwp for operating the W-phase switching element 20, and the operation signal gwn for operating the W-phase switching element 22.

  In the above configuration, when the output signals gu1, gv1, and gw1 are selected by the switching unit 102, the actual currents iu, iv, and iw are made to follow the three-phase currents (command currents) determined by the command currents idc and iqc. The switching elements 12 to 22 are operated by the control. At this time, the voltages applied to the three phases follow the command voltages vuc1, vvc1, and vwc1.

<Rectangular wave control>
The torque estimation unit 120 estimates the output torque of the electric motor 4 based on the actual currents id and iq on the dq axis output from the two-phase / three-phase conversion unit 80. The estimated torque Te may be calculated by the following equation using, for example, the torque constant Kt, d-axis inductance Ld, and q-axis inductance Lq of the electric motor 4.

Te = Kt × iq− (Ld−Lq) × id × iq
The vqc calculation unit 122 calculates the command voltage vqc2 on the q axis based on the difference between the required torque Tc and the estimated torque Te. On the other hand, the vdc calculation unit 124 calculates the command voltage vdc2 on the d axis based on the command voltage vqc2 and the voltage VB of the battery 42. The vqc calculation unit 122 and the vdc calculation unit 124 perform processing for determining the phase of the voltage vector while the length of the voltage vector determined by the command voltages vqc2 and vdc2 is determined according to the voltage VB of the battery 42. . Then, the two-phase / three-phase conversion unit 126 converts the command voltages vqc2 and vdc2 into three-phase command voltages vuc2, vvc2, and vwc2. These command voltages vuc2, vvc2, and vwc2 are substantially sinusoidal signals. In addition, the output signal generation unit 128 generates output signals gu2, gv2, and gw2 based on the command voltages vuc2, vvc2, and vwc2. Here, the output signal gu2 becomes logic “H” when the command voltage vuc2 is zero or more, and becomes logic “L” when it is less than zero. Further, the output signal gv2 becomes logic “H” when the command voltage vvc2 is equal to or greater than zero, and becomes logic “L” when the command voltage vvc2 is less than zero. Further, the output signal gw2 becomes logic “H” when the command voltage vwc2 is zero or more, and becomes logic “L” when the command voltage vwc2 is less than zero. These output signals gu2, gv2, and gw2 are output to the switching unit 102.

  The command voltages vuc2, vvc2, and vwc2 have a period that is substantially equal to the rotation period of the electrical angle of the electric motor 4. For this reason, in the output signals gu2, gv2, and gw2, the repetition cycle of the logic “H” and the logic “L” substantially coincides with one cycle of the electrical angle. For this reason, when the output signals gu2, gv2, and gw2 are selected by the switching unit 102 in the above configuration, the upper switching elements 12, 16, and 20 and the lower switching elements 14, 18, and 22 of each phase arm are alternated. The cycle of turning on and off substantially coincides with one cycle of the electrical angle. For this reason, at the time of the rectangular wave control in which the output signals gu2, gv2, and gw2 are selected by the switching unit 102, the voltage applied to each phase of the electric motor 4 changes to a rectangular wave shape, and the cycle of the change is an electrical angle. It becomes substantially equal to one cycle.

<Switching process>
FIG. 3 shows a region where PWM control is performed and a region where rectangular wave control is performed. As shown in the figure, the PWM control is performed from the low rotation speed region to the medium rotation speed region, and the high rotation speed region is the region where the rectangular wave control is performed. The boundary between the region for performing PWM control and the region for performing rectangular wave control is on the lower rotational speed side as the required torque Tc is larger. Here, the reason why the PWM control is switched to the rectangular wave control in the high rotation speed region is as follows.

  The upper limit value of the voltage that can be applied to each phase of the electric motor 4 is the voltage VB of the battery 42. Therefore, when the maximum value of the command voltages vuc1, vvc1, and vwc1 is “½” or more of the voltage VB, in other words, when the modulation factor is “1” or more, the voltage is actually applied to each phase of the motor 4. Cannot be set to the command voltages vuc1, vvc1, vwc1. FIG. 4A shows the transition of the voltage applied to each phase when the modulation rate is “1”, and FIG. 4B shows the change applied to each phase when the modulation rate is greater than “1”. The transition of the applied voltage is shown. As shown in the figure, when the modulation rate is larger than “1”, the amplitude of the voltage applied to each phase is limited by “½” of the voltage VB of the battery 42. Must not. However, even in this case, as compared with the voltage shown in FIG. 4A, the utilization of the voltage is improved only in the region indicated by the oblique line in FIG. Thereby, the effective value of the voltage applied to each phase can be increased as compared with that shown in FIG. For this reason, it is possible to flow a three-phase command current determined by the command currents idc and iqc to the motor 4. Therefore, even if the maximum value of the command voltages vuc1, vvc1, and vwc1 is equal to or greater than “½” of the voltage VB, the PWM control is continued to cause the motor 4 to have a three-phase determined by the command currents idc and iqc. It is possible to pass an electric current.

  As the maximum values of the command voltages vuc1, vvc1, and vwc1 increase, finally, the voltage applied to each phase of the motor 4 is “VB / 2” in the same cycle as the command voltages vuc1, vvc1, and vwc1. ”And“ −VB / 2 ”. However, theoretically, it is known that the controllability by PWM control is extremely lowered when the modulation rate becomes “1.28”. For this reason, in this embodiment, the maximum value of the command voltages vuc1, vvc1, and vwc1 is a value that is “1.28 / 2” times the voltage VB of the battery 42, thereby switching from PWM control to rectangular wave control.

  Specifically, the switching control unit 130 illustrated in FIG. 2 takes in the command voltages vdc1 and vqc1 that define the command voltages vuc1, vvc1, and vwc1, and operates the switching unit 102 based on the command voltages. FIG. 5 shows a procedure of processing related to switching from PWM control to rectangular wave control among the processing performed by the switching control unit 130. This process is repeatedly executed by the microcomputer 50, for example, at a predetermined cycle during a period in which PWM control is performed.

  In this series of processes, first, in step S10, it is determined whether or not the length of the voltage vector determined by the command voltages vdc1 and vqc1 is greater than or equal to the limit voltage VL. Here, the limit voltage VL is a value obtained by multiplying the voltage VB by the square roots of “1.28” and “3/8”. The voltage vector length on the dq axis is obtained by multiplying the maximum value of the command voltages vuc1, vvc1, and vwc1 by the square root of “3/2”. When the value when the modulation factor is “1.28” is used as the maximum value, this is a value obtained by multiplying “VB / 2” by “1.28”. For this reason, it is possible to determine whether or not the maximum value of the command voltages vuc1, vvc1, and vwc1 is equal to or larger than the value obtained by multiplying “VB / 2” by “1.28” by the above step S10. When an affirmative determination is made in step S10, in step S12, the switching unit 102 is operated to select the output signals gu2, gv2, and gw2, thereby switching from PWM control to rectangular wave control.

  When a negative determination is made in step S10 or when the process of step S12 is completed, this series of processes is temporarily ended.

  FIG. 6 shows currents on the dq axis that can be taken by PWM control and rectangular wave control. In the figure, a command current curve CL indicated by a solid line is a curve drawn by the command currents idc and iqc generated by the command current generator 82. This curve (command current idc, iqc) is appropriately set according to a request for control of the electric motor 4, but in the present embodiment, the required torque Tc can be realized with a minimum current on the dq axis. Is set by the current. On the other hand, what is indicated by a two-dot chain line in the figure is a limit curve LL that defines a boundary of current that can actually flow through the electric motor 4 on dq. The limit curve LL is determined based on the voltage VB of the battery 42 and the rotation speed. For this reason, during PWM control, the actual currents id and iq cannot exceed the upper limit PM that is the intersection of the command current curve CL and the limit curve LL. Therefore, when the command currents iqc and idc reach the upper limit PM, the control is switched to the rectangular wave control.

  When rectangular wave control is performed, generally, the current on the dq axis does not coincide with the current defined by the command current curve CL. That is, in the rectangular wave control and the PWM control, for example, even if the required torque Tc is the same, the vector V1 and the vector V2 in FIG. The current is different. However, if the current vector length on the dq axis when the torque generated by the rectangular wave control is realized by the PWM control is less than the upper limit PM, the output torque generated by the rectangular wave control is generated by the PWM control. Is possible. For this reason, it is considered that fluctuations in output torque can be suppressed when switching from rectangular wave control to PWM control.

  Therefore, in this embodiment, the equivalent values of the command voltages vuc1, vvc1, and vwc1 required when the output torque generated by the rectangular wave control is generated by the PWM control are estimated, and based on this, the command voltages vuc1, vvc1 are estimated. , Vwc1 is determined to be equal to or lower than a predetermined voltage. Here, the predetermined voltage is determined according to the limit curve LL. And when it is below a predetermined voltage, it changes to PWM control, and the fluctuation | variation of the output torque accompanying switching is suppressed.

  FIG. 7 shows a procedure of processing related to switching to PWM control according to the present embodiment. This process is performed by the torque estimation unit 120 and the switching control unit 130 of FIG. 2, and specifically, is repeatedly executed by the microcomputer 50 at a predetermined cycle during a period of rectangular wave control. .

  In this series of processing, first, actual currents id and iq are acquired in step S20. In the subsequent step S22, the estimated torque Te is calculated based on the actual current. The processes in steps S20 and S22 are performed by the torque estimating unit 120 shown in FIG. In subsequent step S24, based on the estimated torque Te, command currents idc and iqc for generating this by PWM control are estimated. As shown in FIG. 8, this is a process for obtaining the command currents idc and iqc when the output torque becomes the estimated torque Te in the command current curve CL. This may be obtained by two functions that define the relationship between the estimated torque Te and the command currents idc and iqc, or two maps that define the relationship between the estimated torque Te and the command currents idc and iqc. You may ask for.

  In subsequent step S26, based on the estimated command currents idc and iqc, command voltages vdc1 and vqc1 for generating the estimated currents are estimated. This can be calculated by substituting the estimated command currents idc and iqc as currents on the dq axes of the above formulas (cd) and (cq).

  In the subsequent step S28, it is determined whether or not the length of the voltage vector determined by the estimated command voltages vdc1 and vqc1 is equal to or less than a value obtained by subtracting the predetermined value α from the limit voltage VL. This process is for determining whether or not the command voltages vuc1, vvc1, and vwc1 required when the estimated torque Te is generated by the PWM control become a value smaller than the modulation factor “1.28”. is there. Here, the predetermined value α is a positive number, and switching from PWM control to rectangular wave control by the process shown in FIG. 5 and switching from rectangular wave control to PWM control by the process shown in FIG. It is provided to avoid hunting. When an affirmative determination is made in step S28, the output signals gu1, gv1, and gw1 are selected in step S30 by operating the switching unit 102 of FIG. 2, and switching to PWM control is performed. Incidentally, when the rectangular wave control is performed, the integral term in the PI control units 84 and 86 shown in FIG. 2 is set to be kept at zero.

  When a negative determination is made in step S28 or when the process of step S30 is completed, this series of processes is temporarily terminated.

  FIG. 9 shows the transition of the voltage vector on the dq axis accompanying switching between PWM control and rectangular wave control according to the present embodiment. Specifically, in FIG. 9, an actual voltage vector Vr is indicated by a solid line, and a voltage vector Ve required for generating the current output torque by PWM control is indicated by a one-dot chain line. The limit voltage VL is shown.

  FIG. 9A shows a case where the length of the voltage vector on the dq axis is shorter than the limit voltage VL and PWM control is performed. FIG. 9B shows a case where the length of the voltage vector Ve becomes the limit voltage VL and the PWM control is switched to the rectangular wave control. FIG. 9C shows a case where rectangular wave control is performed. At this time, the length of the voltage vector Ve required for generating the generated output torque by PWM control is longer than the limit voltage VL. Here, the length of the voltage vector Vr coincides with the limit voltage VL, but the high rotation speed control is realized by advancing the phase compared with the PWM control. Similarly, FIG. 9D also shows a case where the length of the voltage vector Ve required for generating the generated output torque by PWM control is longer than the limit voltage VL and rectangular wave control is performed. Yes. On the other hand, in FIG. 9E, the length of the voltage vector Ve required for generating the generated output torque by the PWM control is shorter than the limit voltage VL by a predetermined value α, and the rectangular wave control is performed. A time when switching to PWM control is shown. FIG. 9F shows the time when the PWM control after switching is performed.

  FIG. 10 shows a time chart regarding the transition of the voltage vector shown in FIGS. 9 (a) to 9 (f). Here, FIG. 10A corresponds to the transition shown in FIG. 9A to FIG. 9C, and FIG. 10B shows FIG. 9D to FIG. This corresponds to the transition shown in (f). As shown in FIG. 10 (a), switching to rectangular wave control by switching the length of the voltage vector Vr to the limit voltage VL performs switching while suppressing fluctuations in the output torque (estimated torque Te). be able to. Moreover, by switching to the rectangular wave control, the voltage utilization factor (effective value of the primary component of the line voltage with respect to the voltage VB of the battery 42) in the high rotation speed region can be improved, and the rotation speed of the motor 4 can be increased. It is possible to control the rotation speed. Further, as shown in FIG. 10B, when the length of the voltage vector Ve required to generate the generated output torque by PWM control is shorter than the limit voltage VL, switching to PWM control is performed. The switching can be performed while suitably suppressing the fluctuation of the output torque (estimated torque Te).

  Further, as in the present embodiment, switching from rectangular wave control to PWM control is performed based on command voltages vdc1 and vqc1 (voltage vector Ve) required for generating the generated output torque by PWM control. Thus, not only suppression of fluctuations in the output torque but also appropriate switching can be performed near the boundary between the two controls shown in FIG. That is, at the operating point P in the high rotational speed and low torque region shown in FIG. 11A, the current vector during the rectangular wave control may be as shown in FIG. 11B. . In this case, since the current vector approximates the current vector determined by the command current curve CL, there is a possibility that it is erroneously determined as the switching timing from the rectangular wave control to the PWM control. On the other hand, in this embodiment, when the command voltages vdc1 and vqc1 are estimated in step S26 of FIG. 7, the switching timing is set to the actual current id, in order to use the above formulas (cd) and (cq). In addition to iq, the determination is based on the rotation speed. For this reason, it can be suitably avoided that the operation point P shown in FIG. 11A is erroneously determined as the switching timing from the rectangular wave control to the PWM control.

  According to the embodiment described in detail above, the following effects can be obtained.

  (1) The command voltages vdc1 and vqc1 when the output torque generated by the rectangular wave control is generated by the PWM control are estimated. Accordingly, it can be determined whether or not the output torque fluctuation can be suppressed when switching from the rectangular wave control to the PWM control.

  (2) When the length of the voltage vector defined by the estimated command voltages vdc1 and vqc1 is equal to or less than a predetermined voltage, the mode is switched to PWM control. For this reason, it is possible to quantify whether or not the torque fluctuation associated with the switching from the rectangular wave control to the PWM control can be suitably suppressed by the predetermined voltage.

  (3) The predetermined voltage is set to the limit voltage VL which is a value obtained by multiplying the voltage VB of the battery 42 by the square root of “1.28” and “3/8”. Thereby, when switching from the rectangular wave control to the PWM control, the controllability of the PWM control can be kept high. For this reason, when switching from the rectangular wave control to the PWM control, appropriate control can be performed so as to suppress a sudden change in the output torque.

  (4) Based on the actual currents id, iq of the electric motor 4 and the rotational speed of the electric motor 4, the command voltages vdc1, vqc1 for generating the output torque generated by the rectangular wave control by PWM control are estimated. Thereby, the command voltages vdc1 and vqc1 can be suitably estimated.

  (5) The command currents idc and iqc for generating the output torque by PWM control were estimated, and the command voltages vdc1 and vqc1 were estimated based on the command currents idc and iqc and the detected rotation speed. Thereby, based on said formula (cd) and (cq), command voltage vdc1 and vqc1 can be estimated suitably.

  (6) The voltage on the dq axis as an equivalent value was estimated instead of the three-phase voltage required for generating the output torque generated by the rectangular wave control by the PWM control. Thereby, since it is not necessary to consider the amplitude of a voltage, the process concerning switching can be performed simply.

  (7) Since the length of the voltage vector defined by the command voltages vdc1 and vqc1 by the PWM control becomes the limit voltage VL, the PWM control is switched to the rectangular wave control. Thus, while using PWM control as much as possible, it is possible to switch to rectangular wave control before the controllability of output torque by PWM control decreases.

(Second Embodiment)
Hereinafter, the second embodiment will be described with reference to the drawings with a focus on differences from the first embodiment.

  In the above embodiment, the estimated torque Te is calculated based on the actual currents id and iq, and it is determined whether or not it is the switching timing from the rectangular wave control to the PWM control based on the estimated torque Te and the rotation speed. This means that the timing for switching from the rectangular wave control to the PWM control can be determined based on the actual currents id, iq, the rotation speed, and the voltage VB of the battery 42. Therefore, in this embodiment, the timing for switching from the rectangular wave control to the PWM control is determined based on the map based on the actual currents id, iq and the rotation speed.

  FIG. 12 shows a map used in the present embodiment. As shown in the figure, in this embodiment, map values of “1” and “0” are obtained for each point on the four dimensions defined by the voltage VB of the battery 42, the actual currents id, iq, and the rotation speed. Either value is defined. “1” indicates that the length of the voltage vector (vdc1, vqc1) required for generating the currently generated output torque by PWM control is the limit voltage VL (more precisely, VL−α). It is bigger than that. Also, “0” indicates that the length of the voltage vector defined by the command voltages vdc1 and vqc1 required for generating the currently generated output torque by PWM control is the limit voltage VL (more precisely, VL-α) or less. This map can be created by performing the process shown in FIG. 7 for each operating point determined by the actual currents id, iq and the rotation speed. By storing this map in the microcomputer 50, switching from rectangular wave control to PWM control can be performed as in the first embodiment.

  FIG. 13 shows a procedure of processing related to switching from rectangular wave control to PWM control according to the present embodiment. This process is repeatedly executed at a predetermined cycle by the microcomputer 50 during the period in which the rectangular wave control is performed.

  In this series of processing, first, in step S40, a map value is calculated using the map shown in FIG. 12 from the voltage VB, the actual currents id, iq, and the rotation speed. Here, in the case where the operating point determined by the actual currents id, iq and the rotational speed or the voltage VB is not a point where the map value is defined, an interpolation calculation may be performed. In step S42, it is determined whether or not the calculated map value is “0”. In this process, the length of the voltage vector (vdc1, vqc1) required for generating the currently generated output torque by PWM control is equal to or less than the limit voltage VL (more precisely, VL-α). Whether or not. And when it is judged as "0" in Step S42, it changes to PWM control in Step S44.

  When a negative determination is made in step S42 or when the process of step S44 is completed, this series of processes is temporarily terminated.

  According to the embodiment described above, the following effects can be obtained.

  (8) Switching from rectangular wave control to PWM control was performed based on the actual currents id, iq and the rotation speed. As a result, in a region where control by PWM control is appropriate, switching to PWM control can be performed while suppressing fluctuations in output torque.

(Third embodiment)
Hereinafter, the third embodiment will be described with reference to the drawings with a focus on differences from the first embodiment.

  In the above embodiment, the command voltages vdc1 and vqc1 for realizing the output torque generated during the rectangular wave control by the PWM control are estimated by the models (the above formulas (cd) and (cq)). By the way, the model changes in accordance with the state of the electric motor 4. Specifically, the inductances Ld and Lq change according to the magnetic field generated by the current flowing through the electric motor 4, for example. Further, the resistance R varies depending on the temperature of the electric motor 4. Therefore, if the command voltages vdc1 and vqc1 are estimated with the inductances Ld and Lq and the resistance R being constant, the estimation accuracy may vary depending on changes in the inductances Ld and Lq and the resistance R.

  Therefore, in the present embodiment, an error in switching timing to PWM control based on the estimated command voltages vdc1 and vqc1 is suppressed in the mode shown in FIG.

  In FIG. 14A, the curve indicated by the solid line is the command current curve CL as in the case of FIG. Now, it is assumed that the current flowing through the electric motor 4 by the rectangular wave control is the current vector V1. At this time, a region in the vicinity of the intersection SP between the equal torque curve indicated by the one-dot chain line and the command current curve CL in FIG. Then, when the current vector by the rectangular wave control shifts from the current vector V1 to the current vector V3, and the tip of the current vector enters the switching area SA, the command voltage vdc1 estimated by the above formulas (cd) (cq), Store vqc1.

  FIG. 14B shows a voltage vector VV3 stored at this time. Here, in the present embodiment, a threshold value Δ for the change amount of the voltage vector for switching from the rectangular wave control to the PWM control is determined. This threshold value Δ is set based on the estimated amount of change in the length of the voltage vector in the period from when the current vector enters the switching area SA to the intersection SP. For this reason, as shown in FIG. 14B, when the estimated voltage vector changes from the voltage vector VV3 to the voltage vector VV4, and the amount of change in the length becomes the threshold value Δ, the actual voltage It is considered that the length of the vector can be made equal to or less than the limit voltage VL (more precisely, VL-α) indicated by a two-dot chain line in FIG. Here, FIG. 14B illustrates a case where the length of the voltage vector VV4 is longer than the limit voltage VL. This is due to an estimation error caused by making the inductances Ld and Lq and the resistance R constant in the above formulas (cd) and (cq). However, even in this case, it is considered that the length of the voltage vector VV4 whose length has changed from the voltage vector VV3 by the threshold Δ is precisely equal to or less than the limit voltage VL. This is because changes in the inductances Ld and Lq and the resistance R during the period in which the estimated voltage vector shifts from the voltage vector VV3 to the voltage vector VV4 can be ignored.

  By performing such processing, in this embodiment, errors in switching to PWM control due to the constant inductances Ld, Lq and resistance R in the above formulas (cd) and (cq) are suppressed. FIG. 15 shows the procedure of the above processing. This process is repeatedly executed by the microcomputer 50 at a predetermined cycle, for example, during rectangular wave control.

  In this series of processing, first, in step S50, based on the current required torque Tc, an intersection SP (switching point) between the command current curve CL and the equal torque curve shown in FIG. 14A is calculated. This process can be performed, for example, by using the command currents idc and iqc when the current requested torque Tc is input to the command current generator 82 shown in FIG. In subsequent step S52, the switching area SA shown in FIG. 14A is set. Here, for example, an area where the difference between the d-axis component and the q-axis component from the switching point is a predetermined amount or less may be set as the switching area.

  In a succeeding step S54, it is determined whether or not the actual currents id and iq have entered the switching region. If it is not within the switching area, the processes of steps S50 and S52 are repeated. If it is determined in step S54 that it is within the switching area, the process proceeds to step S56. In the processes of steps S56 to S60, the processes of steps S22 to S26 of FIG. 7 are performed. When the process of step S60 is completed, it is determined in step S62 whether or not the lengths of the command voltages vdc1 and vqc1 estimated in step S60 immediately after the switching region has been stored. When a negative determination is made in step S62, the lengths of the command voltages vdc1 and vqc1 are stored in step 64, and the process returns to step S56.

  On the other hand, when it is determined in step S62 that the data has been stored, in step S66, is the difference between the stored lengths of the command voltages vdc1 and vqc1 estimated in step S60 equal to or greater than the threshold value Δ? Judge whether or not. And when it is less than threshold value (DELTA), it returns to step S56.

  On the other hand, when it is determined that the value is equal to or greater than the threshold value Δ, processing for switching to PWM control is performed in step S68.

  FIG. 16A shows changes in the rotational speed and output torque associated with switching from PWM control to rectangular wave control according to the present embodiment. On the other hand, FIG. 16B shows a transition example of the rotation speed and the output torque at the time of switching from the PWM control to the rectangular wave control in the first embodiment. In the example shown in FIG. 16B, the output torque fluctuates when switching from PWM control to rectangular wave control. This is because the process shown in FIG. 7 is performed in accordance with the switching to the rectangular wave control. At this time, if there is an error in the estimation of the command voltages vdc1 and vqc1, the rectangular wave control is continued. This is because it is erroneously determined that it is time to switch to the PWM control in spite of the state to be changed, and the control is switched to the PWM control. In this case, since the voltage required for generating the required torque Tc by the PWM control cannot be applied to the electric motor 4, the current flowing through the electric motor 4 cannot be controlled as desired, and the output torque varies accordingly. .

  On the other hand, in the present embodiment, by performing the processing shown in FIG. 15 above, inappropriate switching from rectangular wave control to PWM control can be suppressed or avoided. The fluctuation of the output torque accompanying the switching to can be suitably suppressed.

  According to this embodiment described above, the following effects can be obtained in addition to the effects (1) and (3) to (7) of the first embodiment.

  (9) Processing for suppressing errors due to changes in the resistance R and the inductances Ld and Lq of the motor 4 with respect to the timing of switching to PWM control based on the estimated command voltages vdc1 and vqc1 was performed. Thereby, the change of the output torque of the electric motor 4 at the time of PWM control can be suppressed suitably.

  (10) Based on the amount of change in the length of the command voltages vdc1 and vqc1 since it is determined that the current flowing through the motor 4 enters the switching region, the voltage required by the PWM control is for switching to the same control. The case where it became below a predetermined voltage was judged. Thereby, it is highly accurate whether or not the command value of the voltage required when the output torque generated by the rectangular wave control is generated by the PWM control is a value that can maintain the controllability of the PWM control high. Can be judged.

(Fourth embodiment)
Hereinafter, the fourth embodiment will be described with reference to the drawings with a focus on differences from the third embodiment.

  FIG. 17 shows a procedure for switching processing from rectangular wave control to PWM control according to the present embodiment. This process is repeatedly executed by the microcomputer 50 at a predetermined cycle, for example, during rectangular wave control. In FIG. 17, the same step numbers are assigned to the processes corresponding to the processes shown in FIG.

  As shown in the figure, in the present embodiment, switching to PWM control is performed based on the amount of change in phase instead of the amount of change in length of the voltage vector after it is determined that the switching region is entered. That is, when entering the switching region, in step S70, the phase φ of the command voltages vdc1 and vqc1 estimated at that time in step S60 is stored. Thereafter, the estimated change in the voltage vector is monitored, and when the difference of the phase φ with respect to the phase becomes equal to or less than the threshold β (step S72: YES), the control is switched to PWM control (step S68). That is, as shown in FIG. 14B, the phase when the PWM control is performed is delayed from the vector when the rectangular wave control is performed. For this reason, when the phase changes from the stored phase φ to the retard side by the threshold β or more, the control is switched to PWM control.

  As described above, when the output torque generated by the rectangular wave control is generated by the PWM control, the phase φ of the voltage vector (command voltages vdc1, vqc1) is used as a parameter related to the voltage required as the command value. The timing at which the length of the voltage vector becomes equal to or less than the limit voltage VL can be determined with high accuracy.

  Also according to the present embodiment described above, the same effects as those of the third embodiment can be obtained.

(Fifth embodiment)
Hereinafter, a fifth embodiment will be described with reference to the drawings, focusing on differences from the first embodiment.

  FIG. 18 shows a procedure for switching processing from rectangular wave control to PWM control according to the present embodiment. This process is repeatedly executed by the microcomputer 50 at a predetermined cycle, for example, during rectangular wave control.

  In this series of processing, first, in step S80, a command required to generate the output torque generated by the rectangular wave control based on the actual currents id, iq, the rotation speed, and the temperature of the motor 4 by the PWM control. The voltages vdc1 and vqc1 are map-calculated. Here, the map receives four parameters such as the actual currents id and iq, the rotation speed, and the temperature of the electric motor 4, and determines the command voltages vdc1 and vqc1 based on these parameters. This can be realized by creating in advance a map that defines the relationship between the command voltages vdc1 and vqc1 and the above four parameters. This map is adapted in advance by experiments or the like so that the required command voltages vdc1 and vqc1 change according to changes in the inductances Ld and Lq and the resistance R according to the four parameters. For this reason, the command voltages vdc1 and vqc1 estimated using this map have errors such as those estimated by the above formulas (cd) and (cq) while assuming that the inductances Ld and Lq and the resistance R are constant. Does not occur.

  When the process of step S80 is completed, the same processes as steps S28 and S30 shown in FIG. 7 are performed in the processes of steps S82 and S84.

(Sixth embodiment)
Hereinafter, the sixth embodiment will be described with reference to the drawings with a focus on differences from the fifth embodiment.

  FIG. 19 shows a procedure for switching processing from rectangular wave control to PWM control according to the present embodiment. This process is repeatedly executed by the microcomputer 50 at a predetermined cycle, for example, during rectangular wave control.

  In this series of processing, first, in step S90, based on the actual currents id, iq, the rotation speed, and the temperature of the motor 4, a command required for generating the output torque generated by the rectangular wave control by the PWM control. A map operation is performed on the phase φ of the voltages vdc1 and vqc1. Here, the map receives four parameters, ie, the actual currents id, iq, the rotation speed, and the temperature of the motor 4, and determines the phase φ of the command voltages vdc1, vqc1 based on these parameters. This can be realized by preparing in advance a map that defines the relationship between the command voltages vdc1 and vqc1 and the above four parameters. This map is adapted in advance through experiments or the like so that the phases of the required command voltages vdc1 and vqc1 change according to changes in the inductances Ld and Lq and the resistance R due to the four parameters. For this reason, the phase of the command voltages vdc1 and vqc1 estimated using this map seems to be estimated by the above formulas (cd) and (cq) while assuming that the inductances Ld and Lq and the resistance R are constant. No errors occur.

  When the process of step S90 is completed, it is determined in step S92 whether or not the phase φ substantially matches the predetermined value γ. In this process, it is determined whether or not the output torque generated by the rectangular wave control can be generated by the PWM control. Here, the predetermined value γ is map-calculated based on the rotation speed, the torque, and the voltage VB of the battery 42. This is because the power factor is normally variably set according to the state of the motor 4 in the output control of the motor 4. For this reason, the phase suitable for switching to PWM control changes in accordance with the operating state of the electric motor 4. Parameters for setting an appropriate predetermined value γ according to this change are the rotational speed, torque, and voltage VB.

  When the phase φ reaches the predetermined value γ, in step S94, processing similar to that in step S30 shown in FIG. 7 is performed.

  Also in the present embodiment described above, an effect according to the effect of the fifth embodiment can be obtained.

(Seventh embodiment)
Hereinafter, the seventh embodiment will be described with reference to the drawings with a focus on differences from the first embodiment.

  In the present embodiment, the estimation error when estimating the command voltages vdc1 and vqc1 for realizing the output torque generated during the rectangular wave control by the PWM control by the model (the above formulas (cd) and (cq)) is calculated. Learning is performed based on the voltage applied to the motor 4 during PWM control. Specifically, in the present embodiment, at the time of switching from PWM control to rectangular wave control, the command currents idc and iqc are estimated in the manner of step S24 of FIG. The command voltages vdc1 and vqc1 are estimated based on the currents idc and iqc and the rotation speed. The difference between these estimated command voltages vdc1 and vqc1 and the voltage applied to the motor 4 by PWM control (command voltages vdc1 and vqc1 input to the two-phase three-phase converter 92 shown in FIG. 2) This is considered to be the above estimation error. Therefore, in this embodiment, the length of the voltage vector (command voltages vdc1, vqc1) estimated at this time is used as a value corrected so that the limit voltage VL compensates for the estimation error of the model.

  FIG. 20 shows the principle of switching from rectangular wave control to PWM control according to this embodiment. Specifically, FIG. 20A shows the transition of the rotation speed, FIG. 20B shows the transition of the length (output voltage) of the voltage vector output from the inverter 10, and FIG. The transition of the length (estimated voltage) of the estimated voltage vector is shown. As shown in the drawing, the estimated voltage at that time is stored at time t1 when the PWM voltage is switched to the rectangular wave control when the output voltage becomes the limit voltage VL. Then, at time t2 when the estimated voltage becomes equal to or lower than the stored value, the rectangular wave control is switched to the PWM control. Thereby, switching can be performed when the output voltage required when the output torque generated by the rectangular wave control is generated by the PWM control becomes equal to or lower than the limit voltage VL.

  However, in practice, the model error varies depending on the current flowing through the motor 4 and the temperature. For this reason, the current and the temperature of the motor 4 that flowed to the motor 4 when switching from PWM control to rectangular wave control, and the current and the motor 4 that flow to the motor 4 when switching from rectangular wave control to PWM control. If there is a difference between the temperature and the estimated voltage vector, the length of the estimated voltage vector may not be a value corrected so that the limit voltage VL compensates for the estimation error of the model. That is, for example, as shown in 1) of FIG. 21, after switching from PWM control to rectangular wave control at high rotational speed and small torque, from rectangular wave control to PWM control at medium rotational speed and large torque. In the case of switching, it is considered that the model error also changes because the current at the time of switching is greatly different. Also, for example, as shown in 2), after switching from PWM control to rectangular wave control at high rotational speed and medium torque, switching from rectangular wave control to PWM control at medium rotational speed and large torque In addition, it is considered that the model error changes because the current at the time of switching is greatly different.

  Therefore, in the present embodiment, among the above models, the q-axis inductance is variably set based on the current. Thus, the reason why only the q-axis inductance is variably set is as follows. In the region where the rectangular wave control is performed, the rotational speed is basically large, and therefore, the interference term is dominant in the model. For this reason, the influence of the fluctuation of the model resistance on the estimation error can be ignored. For this reason, the d-axis inductance, the q-axis inductance, and the back electromotive force constant φ are problematic as the parameters that can be varied among the model parameters.

  FIG. 22 shows a calculation result of the fluctuation of the estimated voltage vector length (estimated voltage) when any one of the d-axis inductance, the q-axis inductance, and the counter electromotive force constant φ is changed. FIG. 22 shows the percentage of the variation amount of the ratio of the estimated voltage when any one parameter is varied with respect to the estimated voltage when all the parameters are fixed. As shown in the figure, when the q-axis inductance is changed (solid line), the voltage estimation error changes greatly, whereas the d-axis inductance and the counter electromotive force constant φ (broken line, one-dot chain line) are changed. Even if it is made, the estimation error hardly changes. Therefore, by variably setting only the Lq inductance, it is possible to favorably compensate for the estimation error of the model while suppressing an increase in the calculation load of the microcomputer 50 as much as possible.

  However, the input voltage of the inverter 10 varies. On the other hand, the length of the voltage vector estimated when switching from PWM control to rectangular wave control is obtained by correcting the limit voltage VL so as to compensate for the estimation error when the input voltage of the inverter 10 does not fluctuate. It is an appropriate value. Therefore, when the input voltage of the inverter 10 varies, the length of the estimated voltage vector is corrected according to the variation of the input voltage.

  FIG. 23 shows a procedure of processing related to switching to PWM control according to the present embodiment. This process is repeatedly executed by the microcomputer 50 at a predetermined cycle, for example, in the vicinity of a region where rectangular wave control is performed.

  In this series of processing, first, in step S100, the q-axis inductance of the above model is map-calculated based on the current flowing through the electric motor 4. Here, as shown in FIG. 24, the map has a smaller value as the amplitude of the current flowing through the electric motor 4 is larger. In the subsequent step S102, the command currents idc and iqc are estimated based on the required torque Tc. This process can be performed in the manner shown in FIG. However, when the required torque Tc is abrupt, the actual current change cannot follow this, so the output torque of the electric motor 4 does not match this. For this reason, in the present embodiment, a final estimated value is obtained by filtering the current estimated in the manner shown in FIG. As a result, the current for generating the output torque can be estimated with high accuracy while using the required torque Tc.

  In the subsequent step S104, the command voltages vdc1 and vqc1 are estimated using the model based on the command currents idc and iqc and the rotation speed. In step S106, the length Nrm of the estimated voltage vector is calculated. In the subsequent step S108, it is determined whether or not it is time to switch from PWM control to rectangular wave control. This determination is a determination as to whether or not an affirmative determination is made in step S10 of FIG. If it is determined that it is time to switch, in step S110, the limit voltage VL at that time and the length Nrm of the estimated voltage vector are stored as VL0 and Nrm0, respectively.

  On the other hand, when it is determined in step S108 that it is not the time of switching, a limit voltage fluctuation amount ΔVL is calculated in step S112. This is a process of calculating the fluctuation amount of the current limit voltage VL with respect to the limit voltage VL0 stored in step S110. In a succeeding step S114, it is determined whether or not it is a switching timing from the rectangular wave control to the PWM control. Specifically, the current estimated voltage vector length Nrm is compared with a threshold value. Here, the threshold value is obtained by correcting the length Nrm0 by a value “(Nrm0 / VL0) ΔVL” obtained by multiplying the ratio of the length Nrm0 to the limit voltage VL0 stored in step S110 by the variation amount ΔVL. Here, the length Nrm0 is considered to be an appropriate value as a threshold if the voltage of the battery 42 does not fluctuate. On the other hand, the value “(Nrm0 / VL0) ΔVL” is a correction amount for compensating for the change in the length of the estimated voltage vector due to the voltage fluctuation amount ΔVL of the battery 42.

  When an affirmative determination is made in step S114, switching to PWM control is performed in step S116. On the other hand, when the processes of steps S110 and S116 are completed, or when a negative determination is made in step S114, this series of processes is temporarily terminated.

  FIG. 25A shows a transition example of output torque accompanying switching to PWM control according to the present embodiment. As shown in the drawing, according to the present embodiment, fluctuations in output torque when switching to PWM control are suitably suppressed. On the other hand, FIG. 25B shows a case where switching is performed by the processing according to the first embodiment. As shown in the figure, in this case, the output torque varies with switching to PWM control.

  FIG. 26 (a) shows another transition example of the output torque accompanying the switching (transition example of torque when switching to PWM control through the path 2 in FIG. 21). On the other hand, FIG. 26 (b) shows an example of torque transition when switching to PWM control through the route 2) of FIG. 21 using a model with a fixed q-axis inductance. As shown in the figure, in this case, the torque varies upon switching.

  According to the present embodiment described above, the following effects can be obtained in addition to the effects of the first embodiment.

  (11) Command voltages vdc1 and vqc1 when a predetermined torque is generated by PWM control while the d-axis inductance of the model parameters is a constant and the q-axis inductance is variably set according to the current flowing through the motor 4. Estimated. Thereby, the estimation by the said model can be performed with high precision.

  (12) Based on the estimated voltage vector (command voltages vdc1, vqc1) when switching from PWM control to rectangular wave control, the estimation error of the model was learned. Thereby, the model error at the time of switching can be learned with high accuracy. Then, the estimation accuracy of the model can be improved by preferably compensating the influence of the change of the model parameter on the change from the time of switching by the variable setting of the q-axis inductance.

  (13) Judgment of switching to PWM control by correcting the length of the estimated voltage vector when switching from PWM control to rectangular wave control with the current fluctuation amount of voltage VB of battery 42 at the time of switching. A threshold was set. As a result, it is possible to appropriately determine whether or not the torque fluctuation associated with the switching from the rectangular wave control means to the voltage control can be suitably suppressed based on the threshold value.

  (14) The above estimation is performed based on the required torque Tc for the motor 4 and the rotational speed of the motor 4. Thereby, “the output torque generated by the rectangular wave control” can be easily obtained.

  (15) When the required torque Tc is generated by PWM control, the command currents idc and iqc flowing through each phase of the electric motor 4 are estimated, and the PWM control command voltages vdc1 and vqc1 for flowing the command currents idc and iqc are It was estimated based on the detected value of the rotation speed. Thereby, the command voltages vdc1 and vqc1 can be estimated appropriately.

(Eighth embodiment)
Hereinafter, the eighth embodiment will be described with reference to the drawings with a focus on differences from the previous seventh embodiment.

  FIG. 27 shows a procedure of processing related to switching to PWM control according to the present embodiment. This process is repeatedly executed by the microcomputer 50 at a predetermined cycle during the period in which the rectangular wave control is performed. In FIG. 27, the processing corresponding to FIG. 23 is given the same step number for convenience, and the description thereof is omitted.

  In this series of processes, when the process of step S104 is completed, the phase Φ of the estimated voltage vector is calculated in step S106a. If an affirmative determination is made in step S108, the voltage VB and phase Φ of the battery 42 are stored as VB0 and Φ0, respectively, in step S110a. When the process of step S112 is completed, in step S114a, the current phase Φ is compared with a threshold value to determine whether it is the timing for switching to PWM control. This threshold is set by correcting the phase Φ0 stored in step S110a with a correction amount table (ΔVB) corresponding to the voltage fluctuation amount ΔVB.

  Also according to the present embodiment described above, the effect according to the seventh embodiment can be obtained.

(Ninth embodiment)
Hereinafter, the ninth embodiment will be described with reference to the drawings, centering on differences from the previous seventh embodiment.

  FIG. 28 shows a procedure of processing related to switching to PWM control according to the present embodiment. This process is repeatedly executed by the microcomputer 50 at a predetermined cycle, for example, in the vicinity of a region where rectangular wave control is performed. In FIG. 27, the processing corresponding to FIG. 23 is given the same step number for convenience, and the description thereof is omitted.

  In this series of processes, when a negative determination is made in step S108, whether or not the value obtained by correcting the current estimated voltage vector length Nrm is equal to or smaller than the value obtained by subtracting the predetermined value α from the limit voltage VL in step S114b. Based on the above, it is determined whether it is the timing for switching to PWM control. Here, the correction of the current length Nrm is performed by multiplying the length Nrm by the ratio “VL0 / Nrm0” of the limit voltage VL0 to the length Nrm0 stored in step S110b. The ratio “VL0 / Nrm0” is a correction coefficient that corrects the length of the estimated voltage vector to compensate for the estimation error.

  Also according to the present embodiment described above, the effect according to the seventh embodiment can be obtained.

(Tenth embodiment)
Hereinafter, the tenth embodiment will be described with reference to the drawings with a focus on differences from the previous seventh embodiment.

  FIG. 29 shows a processing procedure for switching to PWM control according to the present embodiment. This process is repeatedly executed by the microcomputer 50 at a predetermined cycle, for example, in the vicinity of a region where rectangular wave control is performed. In FIG. 29, the processing corresponding to FIG. 23 is given the same step number for convenience, and the description thereof is omitted.

  In this series of processing, it is determined in step S108c whether or not it is the timing at which the estimation error of the model can be learned. Specifically, it is determined whether PWM control is being performed and the rotational speed is equal to or higher than a predetermined speed. Here, the reason why the rotation speed is equal to or higher than the predetermined speed is that the application area of the model in which the q-axis inductance is variably set in the map shown in FIG. 24 is the high rotation speed area. That is, as described above, the fluctuation of the estimation accuracy due to the fluctuation of the q-axis inductance is dominant in the high rotation speed region where the interference term of the model is dominant. Judge whether or not. Also, the time when the PWM control is being performed is to acquire a value to be compared with the estimated value of the model.

  When an affirmative determination is made in step S108c, in step S109, the length NRM of the command voltage vector for PWM control (the length of the vector input to the two-phase three-phase converter 92 shown in FIG. 2) is acquired. To do. In the subsequent step S110c, the length Nrm of the estimated voltage vector is stored as Nrm0.

  On the other hand, when a negative determination is made in step S108c, in step S114c, based on whether or not the correction of the current length Nrm of the estimated voltage vector is equal to or less than the limit voltage VL minus the predetermined value α. It is determined whether it is the timing for switching to PWM control. Here, the correction of the current length Nrm is performed by multiplying the current length Nrm by the ratio “NRM / Nrm0” of the length NRM stored in step S109 to the length Nrm0 stored in step S110c. . This ratio “NRM / Nrm0” is a correction coefficient for correcting the length of the estimated voltage vector to compensate for the estimation error.

  Also according to the present embodiment described above, the effect according to the seventh embodiment can be obtained.

(Other embodiments)
Each of the above embodiments may be modified as follows.

  In the first embodiment, instead of the processing in steps S20 to S26 of FIG. 7, the lengths of the command voltages vdc1, vqc1 and the voltage vectors (vdc1, vqc1) are calculated from the actual currents id, iq and the rotation speed. You may perform the process which carries out map calculation. The map at this time can also be created in the same manner as in the second embodiment.

  In the first embodiment, instead of directly estimating the three-phase voltage required as the command voltage when the output torque generated by the rectangular wave control is generated by the PWM control, Although the voltage on the dq axis is estimated, the present invention is not limited to this. For example, the voltage on the αβ axis may be estimated, or the three-phase voltage may be estimated directly.

  Switching from the rectangular wave control to the PWM control is performed by changing the voltage VB of the battery 42 to “1” when the three-phase voltage required as the command voltage when the output torque generated by the rectangular wave control is generated by the PWM control. .28 / 2 "(or a value that is smaller by a hysteresis width than a value for switching from PWM control to rectangular wave control) or less. Switch to PWM control by providing an arbitrary predetermined voltage equal to or lower than the value obtained by multiplying the voltage VB of the battery 42 by “1.28 / 2” and switching to PWM control when the three-phase voltage falls below the predetermined voltage. In this case, the controllability of the PWM control can be improved.

  In addition, switching from PWM control to rectangular wave control is not limited to that performed when the command voltages vuc1, vvc1, and vwc1 are equal to or higher than the value obtained by multiplying the voltage VB of the battery 42 by “1.28 / 2”. . However, it is desirable to perform switching when the voltage VB of the battery 42 is equal to or greater than a predetermined value equal to or less than a value obtained by multiplying the voltage VB of “1.28 / 2”.

  In each of the above embodiments, the maximum value of the command value that can maintain high controllability of the PWM control is set to “1.28 × 1/2” of the input voltage of the inverter. Here, the value of the “1.27” range, which is an accurate value calculated theoretically, is rounded up to “1.28”. However, the third digit of the decimal point may be rounded down to “1.27”.

  In the previous second embodiment, the map data shown in FIG. 12 is likely to be large in view of the wide range of values that the actual currents id and iq can take in the rectangular wave control region. . Therefore, an operation in which the length of the voltage vector (vdc1, vqc1) required for generating the currently generated output torque by PWM control is equal to or less than the limit voltage VL (more precisely, VL-α). A map is created only for the points, and in the process shown in FIG. 13, the operating point defined by the actual currents id, iq and the rotational speed does not match the operating point that defines the map value or is interpolated by the same operating point. When the point cannot be used, the map value may be calculated as “1”. As a result, the number of stored data can be reduced.

  After completion of the process of step S26 of FIG. 7, the phases of the estimated command voltages vdc1 and vqc1 are calculated, and when this phase matches the threshold value γ shown in step S92 of FIG. You may switch to control.

  In the previous third and fourth embodiments, the switching point is calculated based on the required torque Tc. However, the present invention is not limited to this. For example, the switching point may be calculated based on the estimated torque Te or the actual currents id and iq. Good.

  -You may variably set the distance between the boundary of the switching region and the switching point in the third embodiment and the fourth embodiment according to the actual current id, iq, and the like.

  -Instead of calculating the switching region in the third embodiment and the fourth embodiment each time, it may be set in advance as a region from the d-axis rather than the command current curve CL.

  In the first, third, and fourth embodiments, when the output torque generated by the rectangular wave control is generated by the PWM control, the parameters relating to the voltage required as the command value are the actual currents id, iq and Although the estimation is based on the rotational speed, the present invention is not limited to this. For example, the estimation may be based on the required torque Tc and the rotational speed as in the previous seventh to tenth embodiments.

  In the second embodiment, the switching timing to the PWM control is determined based on the voltage VB of the battery 42, the actual currents id, iq, and the rotation speed. However, the present invention is not limited to this, for example, the voltage VB of the battery 42, the request The timing for switching to PWM control may be determined based on the torque Tc and the rotation speed.

  In the previous seventh to tenth embodiments, when the output torque generated by the rectangular wave control is generated by the PWM control, the parameter value relating to the voltage required as the command value is the required torque and the rotation speed. However, the present invention is not limited to this, and may be estimated based on the actual currents id, iq and the rotation speed, for example.

  In the previous seventh embodiment, the method for setting the limiting voltage for switching to PWM control is not limited to the above. For example, “Nrm0 × VL / VL0” may be used.

  In the eighth embodiment, the switching timing may be determined by comparing the estimated phase φ based on the learning result with the reference phase.

  In the previous seventh, eighth and ninth embodiments, the model error is learned each time the PWM control is switched to the rectangular wave control. In the tenth embodiment, the rotational speed is a predetermined speed in the PWM control. Although the error of the model is learned each time, the present invention is not limited to this. For example, once learning is performed when switching from PWM control to rectangular wave control or when the rotational speed exceeds a predetermined speed in PWM control, re-learning is not performed until the traveling distance exceeds a predetermined value. Also good. Even in this case, by using the learning result, it is possible to estimate the parameter value relating to the voltage required as the command value with high accuracy when the output torque generated by the rectangular wave is generated by the PWM control. it can.

  In the seventh embodiment, the threshold for determining the timing for switching to PWM control may be a value obtained by subtracting the predetermined value α from the value used in the above embodiment.

  ・ Even if q-axis inductance is fixed, learning the estimation error for each torque value allows the timing for switching to PWM control to be determined with high accuracy while compensating for the estimation error of the model. .

  The parameter relating to the voltage required as the command value when the output torque generated by the rectangular wave control is generated by the PWM control is not limited to those exemplified in the above embodiments. For example, it may be a d-axis command voltage.

  The rectangular wave control is not limited to the process illustrated in FIG. For example, the technique described in Patent Document 1 may be used.

  The PWM control is not limited to the process illustrated in FIG. For example, the non-interacting control unit 88 may not be provided. Further, the carrier wave for PWM control is not limited to a triangular wave but may be a sawtooth wave or the like. Further, not only the command currents idc and iqc on the dq axis are obtained from the request torque Tc, but the three-phase command currents iuc, ivc and iwc are directly obtained from the request torque Tc, and the command voltages vuc1, vvc1 and vwc1 are obtained based on this. May be calculated. Here, when the command voltages vuc1, vvc1, and vwc1 are obtained from the command currents iuc, ivc, and iwc, the relational expression that determines the relationship between the three-phase current and the three-phase voltage may be used.

  The voltage control for operating the switching elements 12 to 22 to control the voltage applied to each phase of the electric motor 4 to the command value is not limited to the PWM control. For example, by inputting one-phase command voltages vuc1, vvc1, and vwc1 to one of two input terminals of the hysteresis comparator and the same one-phase actual voltages vu, vv, and vw to the other, the instantaneous voltage value Control may be performed.

  In each of the above embodiments, the input voltage of the inverter 10 is the voltage of the battery 42, but the present invention is not limited to this. For example, a booster circuit that boosts the voltage of the battery 42 may be provided, and the voltage boosted by the booster circuit may be used as the input voltage of the inverter 10.

  -The three-phase motor is not limited to IPMSM. Further, the multiphase rotating machine is not limited to a three-phase motor, and may be, for example, a three-phase generator.

  The control device for the multi-phase rotating machine is not limited to the microcomputer 50 but may be a dedicated integrated circuit (IC), for example.

The figure which shows the electric motor concerning 1st Embodiment, and its control system. The block diagram which shows the process of the output control of the electric motor concerning the embodiment. The figure which shows the area | region of PWM control and rectangular wave control concerning the embodiment. The time chart which shows the problem of PWM control. The flowchart which shows the procedure of the switching process from PWM control concerning the said embodiment to rectangular wave control. The figure explaining the switching conditions from the rectangular wave control concerning the said embodiment to PWM control. 6 is a flowchart showing a procedure for switching processing from rectangular wave control to PWM control according to the embodiment; The figure which shows the estimation aspect of the electric current in the said switching process. The figure which shows transition of the voltage vector by the said switching process. The time chart which shows transition of the voltage vector by the said switching process. The figure explaining the problem of switching based only on an actual current. The figure which shows the map used for switching from the rectangular wave control concerning 2nd Embodiment to PWM control. 6 is a flowchart showing a procedure for switching processing from rectangular wave control to PWM control according to the embodiment; The figure explaining the switching method from the rectangular wave control to PWM control concerning 3rd Embodiment. 6 is a flowchart showing a procedure for switching processing from rectangular wave control to PWM control according to the embodiment; The time chart which shows the switching aspect from PWM control concerning the embodiment to rectangular wave control. The flowchart which shows the procedure of the switching process from the rectangular wave control concerning 4th Embodiment to PWM control. The flowchart which shows the procedure of the switching process from the rectangular wave control concerning 5th Embodiment to PWM control. The flowchart which shows the procedure of the switching process from the rectangular wave control to PWM control concerning 6th Embodiment. The time chart explaining the principle of the switching process from the rectangular wave control to PWM control concerning 7th Embodiment. The figure which shows the problem of switching based on the said switching principle. The figure which shows the relationship between the variation | change_quantity of the parameter of a voltage estimation model, and an error. The flowchart which shows the procedure of the switching process from the rectangular wave control concerning the said embodiment to PWM control. The figure which shows the setting method of the q-axis inductance of the voltage estimation model concerning the embodiment. The time chart which shows the effect of the switching concerning the embodiment. The time chart which shows the effect of the switching concerning the embodiment. The flowchart which shows the procedure of the switching process from the rectangular wave control to PWM control concerning 8th Embodiment. The flowchart which shows the procedure of the switching process from the rectangular wave control to PWM control concerning 9th Embodiment. The flowchart which shows the procedure of the switching process from the rectangular wave control to PWM control concerning 10th Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 4 ... Electric motor, 10 ... Inverter, 12-22 ... Switching element, 50 ... Microcomputer (one Embodiment of the control apparatus of a multiphase rotary machine).

Claims (26)

In a control device for a multi-phase rotating machine that controls the output of the multi-phase rotating machine by operating a switching element of an inverter that supplies power to the multi-phase rotating machine,
Rectangular wave control means for operating the switching element to make the period of change of the voltage applied to each phase of the multiphase rotating machine substantially coincide with the rotation period of the electrical angle of the multiphase rotating machine;
Voltage control means for operating the switching element to control the voltage applied to each phase of the multiphase rotating machine to its command value;
Estimating means for estimating a parameter value relating to a voltage required as the command value when the output torque generated by the control is generated by the voltage control means when the rectangular wave control means is controlled; A control device for a multi-phase rotating machine, comprising:   The estimation means estimates the parameter based on a model including a d-axis inductance and a q-axis inductance of the multi-phase rotating machine, sets the d-axis inductance as a constant, and sets the q-axis inductance to the 2. The control device for a multi-phase rotating machine according to claim 1, wherein the controller is variably set according to a current flowing through the multi-phase rotating machine.   The estimation error of the estimation means is converted into a parameter value relating to a voltage applied to the multiphase rotating machine by the voltage control means and a value estimated by the estimation means when the voltage control means is under control. The controller for a multi-phase rotating machine according to claim 2, further comprising error learning means for learning based on the learning.   The multi-phase rotating machine according to claim 3, wherein the error learning means performs the learning based on a parameter relating to a voltage applied to the multi-phase rotating machine when a rotation speed of the multi-phase rotating machine is not less than a predetermined value. Control device for phase rotating machine.   The estimation error of the parameter estimated by the estimation means is estimated by the estimation means and the value of the parameter relating to the voltage applied to the multiphase rotating machine by the voltage control means when being controlled by the voltage control means. 2. The control device for a multi-phase rotating machine according to claim 1, further comprising error learning means for learning based on the value to be determined.   And switching means for switching to control by the voltage control means when it is determined that the maximum value of the required voltage is equal to or lower than a predetermined voltage based on the learning result by the error learning means and the estimation by the estimation means. The control device for a multi-phase rotating machine according to any one of claims 3 to 5, wherein The error learning means learns an estimated value of the estimating means when switching from the control of the voltage control means to the control of the rectangular wave control means,
The switching unit is configured to determine whether the maximum value of the required voltage is equal to or lower than a predetermined voltage by comparing the value estimated by the estimating unit with a threshold value, and the threshold value 7. The multiphase rotation according to claim 6, wherein: is set based on a value learned by the error learning means, a value at the time of learning by the error learning means and a current value for the input voltage of the inverter. Machine control device. The voltage control means controls the voltage applied to each phase to the command value in order to set the current flowing through the multiphase rotating machine as its command value.
A judgment means for judging whether or not a current flowing through the multi-phase rotating machine falls within a region in the vicinity of the command value of the current when the control by the rectangular wave control means is performed;
And switching means for switching to control by the voltage control means on the basis of a change amount of the estimated value by the estimation means after it is determined that the current value is within a region near the command value. Item 4. The control device for a multiphase rotating machine according to Item 1.   2. The multiphase according to claim 1, further comprising switching means for switching to control by the voltage control means when the maximum value of the required voltage is not more than a predetermined voltage based on the estimation by the estimation means. Control device for rotating machine.   The said estimation means is provided with the map which determines the relationship between the detected value of the rotational speed of the said multiphase rotating machine, the detected value of the electric current which flows through the said multiphase rotating machine, and the said parameter. Multiphase rotating machine control device.   The map defines a detected value of a rotational speed of the multiphase rotating machine, a detected value of a current flowing through the multiphase rotating machine, and a relationship between the temperature of the multiphase rotating machine and the parameter. Item 11. The control device for a multiphase rotating machine according to Item 10. In a control device for a multi-phase rotating machine that controls the output of the multi-phase rotating machine by operating a switching element of an inverter that supplies power to the multi-phase rotating machine,
Rectangular wave control means for operating the switching element to make the period of change of the voltage applied to each phase of the multiphase rotating machine substantially coincide with the rotation period of the electrical angle of the multiphase rotating machine;
Voltage control means for operating the switching element to control the voltage applied to each phase of the multiphase rotating machine to its command value;
When the control by the rectangular wave control means is performed, an estimation means for estimating a parameter relating to a voltage required as the command value when the output torque generated by the control is generated by the voltage control means;
Switching means for switching to control by the voltage control means when the maximum value of the required voltage is equal to or lower than a predetermined voltage for switching to control by the voltage control means based on the estimated value of the estimation means;
A control device for a multi-phase rotating machine, comprising: suppression means for suppressing an error caused by a change in at least one of a resistance component and an inductance component of the multi-phase rotating machine with respect to the switching timing based on the estimated value. . The voltage control means controls the voltage applied to each phase to the command value in order to set the current flowing through the multiphase rotating machine as its command value.
The suppression means, when controlled by the rectangular wave control means, determines whether or not the current flowing through the multiphase rotating machine falls within a region in the vicinity of the current command value; Based on the amount of change in the estimated value by the estimating means since it is determined that it falls within the area near the command value, the maximum value of the required voltage is a predetermined voltage for switching to the control by the voltage controlling means. 13. The control device for a multi-phase rotating machine according to claim 12, further comprising means for determining when:   The suppression means is realized by configuring the estimation means with a map that defines a detected value of a rotational speed of the multiphase rotating machine, a detected value of a current flowing through the multiphase rotating machine, and the parameter. The control device for a multi-phase rotating machine according to claim 12, wherein   The map defines a detected value of a rotational speed of the multiphase rotating machine, a detected value of a current flowing through the multiphase rotating machine, and a relationship between the temperature of the multiphase rotating machine and the parameter. Item 15. The control device for a multiphase rotating machine according to Item 14. In a control device for a multi-phase rotating machine that controls the output of the multi-phase rotating machine by operating a switching element of an inverter that supplies power to the multi-phase rotating machine,
Rectangular wave control means for operating the switching element to make the period of change of the voltage applied to each phase of the multiphase rotating machine substantially coincide with the rotation period of the electrical angle of the multiphase rotating machine;
Voltage control means for operating the switching element to control the voltage applied to each phase of the multiphase rotating machine to its command value;
When the control by the rectangular wave control means is performed, the estimation for estimating either the voltage required as the command value or its equivalent value when the output torque generated by the control is generated by the voltage control means And a control device for a multi-phase rotating machine.   17. The multiphase rotating machine according to claim 16, further comprising a switching unit that switches to control by the voltage control unit when the maximum value of the required voltage is equal to or less than a predetermined voltage based on the estimation by the estimation unit. Control device.   The said predetermined voltage is set to the value below "1.28 * 1/2" times the input voltage to the said inverter, The 6, 7, 9, or 12-15, 17 characterized by the above-mentioned. Control device for multi-phase rotating machine.   The said estimation means performs the said estimation based on the request | required torque with respect to the said multi-phase rotary machine, and the rotational speed of the output shaft of the said multi-phase rotary machine, The said estimation means are characterized by the above-mentioned. The control device for a multiphase rotating machine according to any one of 18.   The estimation unit is configured to calculate a current flowing through each phase of the multiphase rotating machine and an equivalent value when the required torque as the output torque generated by the rectangular wave control unit is generated by the control of the voltage control unit. And a means for estimating any one of them, and a means for estimating a parameter related to a voltage required as a command value of the voltage control means to flow the current based on a detected value of the rotational speed. The control device for a multi-phase rotating machine according to claim 19.   The said estimation means performs the said estimation based on the detected value of the electric current which flows through the said multiphase rotary machine, and the rotational speed of the output shaft of the said multiphase rotary machine. , 16 to 18. The control device for a multiphase rotating machine according to claim 1.   The estimating means estimates the output torque of the multi-phase rotating machine based on the detected value of the current, and generates each phase of the multi-phase rotating machine when the output torque is generated by the control of the voltage control means. Based on the detected value of the rotational speed, a means for estimating one of the flowing current and its equivalent value, and a voltage applied to each phase of the multiphase rotating machine to flow the current and its equivalent value The control device for a multi-phase rotating machine according to claim 21, comprising: an estimating means. The multi-phase rotating machine is a three-phase rotating machine;
The control device for a multi-phase rotating machine according to any one of claims 1 to 22, wherein the estimating means estimates a voltage on a dq axis.   When the maximum value of the command value by the voltage control means is equal to or greater than "1.28 × 1/2" times the input voltage to the inverter, control from the voltage control means to control by the rectangular wave control means The control device for a multi-phase rotating machine according to any one of claims 1 to 23, wherein In a control device for a multiphase rotating machine that controls the output of the multiphase rotating machine by operating a switching element of an inverter that supplies electric power to the multiphase rotating machine,
Rectangular wave control means for operating the switching element to make the period of change of the voltage applied to each phase of the multiphase rotating machine substantially coincide with the rotation period of the electrical angle of the multiphase rotating machine;
Voltage control means for operating the switching element to control the voltage applied to each phase of the multiphase rotating machine to its command value;
Switching from the control by the rectangular wave control means to the control by the voltage control means based on the detection value of the current flowing through each phase of the multiphase rotating machine and the detection value of the rotation speed of the output shaft of the multiphase rotating machine And a control device for a multi-phase rotating machine.   The switching means performs the switching when the maximum value of the voltage required as the command value is less than or equal to a predetermined voltage when the output torque generated by the control by the rectangular wave control means is generated by the voltage control means. The control device for a multi-phase rotating machine according to claim 25, wherein:

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