JP6113651B2 - Multi-phase motor drive - Google Patents

Description

  The present invention relates to a multiphase motor drive device capable of performing stable current control.

  The multiphase electric motor is electrically insulated from each other, and is driven by connecting a single-phase inverter to each winding and supplying AC power. The current control method used for each single-phase inverter feeds back the actual current flowing through each winding of the motor, and performs current control such as proportional-integral control with the current controller for the deviation between the AC current command and the actual current. This is achieved by obtaining a voltage reference.

  As a current control method using an AC current command in a single-phase inverter, the current amplitude command from the speed controller is multiplied by the current pattern (sine wave or rectangular wave) of each phase synchronized with the rotor, and the current command is Thus, an inverter voltage command is given according to the deviation so that the actual current signal detected by the current detector matches the current command (see, for example, Patent Document 1).

  In addition, as a current control method using coordinate transformation (DQ transformation) to orthogonal rotation coordinates, D-axis current and Q-axis current are calculated from the rotor position detected by the position detector and the motor current, There has been a technique for obtaining a voltage command to be given to an electric motor by obtaining a biaxial voltage command so that a deviation between each of these currents and each current command is minimized, and inversely transforming the voltage command (for example, Patent Document 2). reference.).

JP-A-8-242587 (Overall) Japanese Patent Laying-Open No. 2005-269818 (Overall)

  According to the technique disclosed in Patent Document 1, in a multiphase motor drive device using an inverter, since the current command is an alternating current, a phase error and an amplitude error are constantly generated between the current command and the actual current. There is a method of increasing the response gain of the current controller in order to minimize this error, but the error cannot be completely eliminated. If the response gain is increased too much, the control oscillates and becomes unstable. When a phase error and an amplitude error occur, the current does not flow in accordance with the current command, so that there is a problem that the torque ripple increases and the vibration and noise of the multiphase motor drive device increase. Further, if an amplitude error occurs and the actual current becomes higher than the current command, there is a problem that an excessive current flows.

  Further, in Patent Document 2, the actual currents of all single-phase inverters are collectively DQ-converted on orthogonal rotation coordinates. For this reason, some of the plurality of single-phase inverters driving a multi-phase motor are used. There is a problem that the control becomes unstable when is stopped. In addition, it is necessary to send an actual current signal to the common control device for the actual current of all single-phase inverters, which not only complicates the device but also causes an unstable phenomenon due to a signal transmission delay.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a multiphase motor drive device that can suppress phase error and amplitude error and can stably control current. .

In order to achieve the above object, a multi-phase motor driving device of the present invention includes a multi-phase motor having a plurality of windings insulated from each other, and a plurality of units connected to each of the windings and outputting AC power. The single-phase inverter is composed of a single-phase inverter and a host controller that gives a current amplitude command to the single-phase inverter. The single-phase inverter is based on the current amplitude command and a current detector that detects an actual current flowing through the winding. A control device for controlling a current flowing through the winding, wherein the control device develops the current amplitude command into a current command of two axes of a control D axis and a control Q axis; and the current amplitude command Or virtual cosine wave generating means for generating a virtual cosine wave having a phase equal to the amplitude of the real current and having a phase orthogonal to the current amplitude command or the real current, and orthogonal rotation using the real current and the virtual cosine wave seat Having an orthogonal rotation coordinate conversion means for converting said current instruction of the two-axis obtained by the current command calculation unit, so that the current component of the two-axis obtained by the orthogonal rotation coordinate conversion means respectively follow with performing current control, the reference phase of the orthogonal rotation coordinate conversion means in response to said phase difference of each winding of the multi-phase electric motor, with a phase angle shifted separately in each of the single-phase inverters, the polyphase When the direction of the field pole that is rotationally synchronized with the electric motor is the true D axis, the direction of the induced voltage by the field pole perpendicular to the true Q axis is the true Q axis, and the advance angle of the current vector from the true Q axis is the current advance angle, The reference phase of the orthogonal rotation coordinate conversion means is obtained by adding the individually shifted phase angle to the value obtained by converting the rotation angle detected by the rotation angle detector provided in the polyphase motor into an electrical angle, and further rotating the rotation phase. correction Add the corners to get it,
The reference phase of the current command calculation means is obtained by subtracting the rotational phase correction angle from the current advance angle .

  According to the present invention, it is possible to provide a multiphase motor drive device that can suppress phase error and amplitude error and can stably control current.

1 is a block configuration diagram of a multiphase motor drive device according to Embodiment 1 of the present invention. FIG. The figure explaining the phase relationship of the induced voltage and electric current of a multiphase motor. FIG. 3 is a diagram illustrating a phase relationship of current vectors in the first embodiment. The figure which shows the phase relationship of the electric current vector at the time of carrying out rotational coordinate conversion by the control D axis and the control Q axis. The block block diagram of the multiphase motor drive device which concerns on Example 2 of this invention. The block block diagram of the high-order control apparatus of the multiphase motor drive device which concerns on Example 3 of this invention. The vector figure which shows the electric current advance angle for power factor 1 achievement. The figure which shows the current vector and isotorque curve of an embedded magnet type synchronous motor.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a block configuration diagram illustrating an entire multiphase motor driving apparatus according to the first embodiment. The multiphase motor 1 includes a plurality of windings constituting each phase, and the windings are electrically insulated from each other. The multiphase motor 1 is driven by connecting the outputs of the single-phase inverters 21, 22,..., 2N to these windings and supplying AC power. In the present embodiment, the field of the multiphase motor 1 is described as a permanent magnet type. However, even in the case of an electromagnet type, it can be realized by replacing the magnetic pole direction of excitation with a permanent magnet type magnet direction.

  A speed control device 3, which is a common host control device, sends a current amplitude command to each single-phase inverter 21, 22, ... 2N so that the multiphase motor 1 has a rotational speed corresponding to the speed command. . Each of the single-phase inverters 21, 22,... 2N passes an alternating current corresponding to the current amplitude command through the windings of the multiphase motor 1. A mechanical angle is detected by a rotation angle detector 4 attached to the shaft of the multiphase motor 1 and input to the speed control device 3. The actual speed is calculated by differentiating the mechanical angle by the speed detection circuit 31. Then, the subtracter 32 obtains a speed deviation between the speed command and the actual speed and inputs it to the speed controller 33. In the speed controller, proportional-integral control is performed so that the speed deviation is minimized, and a current amplitude command is output. The electrical angle calculation circuit 34 calculates an electrical angle from the mechanical angle according to the number of poles of the multiphase motor 1, and outputs this electrical angle to each single-phase inverter 21, 22,... 2N. Further, the current phase calculation circuit 35 calculates a current advance angle of the winding current of the multiphase motor 1 which is optimum according to the current amplitude command or its torque component, and the current advance angle is calculated for each single-phase inverter 21, 22, ... Output to 2N. For example, in order to set the terminal voltage, winding current, and power factor of the multiphase motor 1 to desired values, the current advance angle is changed with respect to the induced voltage phase. This will be described in detail in Example 3.

  Next, the internal configuration of each single-phase inverter 21, 22, ... 2N will be described. Since the plurality of single-phase inverters have basically the same configuration, the single-phase inverter 21 will be described. The single-phase inverter 21 includes an inverter main circuit 5 and a control circuit 6. The inverter main circuit 5 converts a direct current power source into alternating current by a bridge circuit of a switching element and outputs the alternating current to drive the corresponding winding of the multiphase motor 1. A current detector 51 is provided at the output of the inverter main circuit 5, and this detected current is supplied to the control circuit 6.

  Hereinafter, the internal configuration of the control circuit 6 will be described. The current amplitude command given from the speed control device 3 is input to the current command calculator 61. In the current command calculator 61, the current amplitude command is orthogonal to the D-axis current command in the true D-axis direction and the Q-axis current command in the true Q-axis direction which is a component orthogonal to the current lead angle as a reference phase. Expand on rotating coordinates. That is, the current amplitude command is regarded as a current command vector whose phase is advanced by a current advance angle from the true Q axis, and the current command vector is projected onto the true D axis and the true Q axis. Here, the direction of the magnetic flux vector of the permanent magnet that is the field magnetic pole of the multiphase motor 1 is the true D axis, and the direction of the induced voltage vector by the field magnetic pole orthogonal thereto is the true Q axis. That is, the vector direction of the current flowing through the windings of the multiphase motor 1 is the direction in which the phase is advanced by the current advance angle from the true Q axis. This phase relationship is shown in FIGS. FIG. 2 shows the induced voltage waveform in (a), the phase in (b), the current waveform in (c), and the current phase in (d). Thus, it can be seen that the current phase is advanced by the current advance angle with respect to the induced voltage phase. When this is expressed by the DQ orthogonal rotation coordinates, FIG. 4 is obtained. That is, the phase of the current command vector is advanced by the current advance angle with respect to the induced voltage in phase with the Q-axis current. The vector diagram shown in FIG. 3 also shows the actual operating state controlled as commanded as described below. In this case, the current command vector is simply referred to as a current vector in the sense of indicating the actual current. .

  The D-axis current command and the Q-axis current command, which are the outputs of the current command calculator 61, are respectively compared with the D-axis current and the Q-axis current given from the orthogonal coordinate converter 68 by the subtractor 62 and the subtractor 64, respectively. Are given to the D-axis current controller 63 and the Q-axis current controller 65, respectively. In the D-axis current controller 63 and the Q-axis current controller 65, proportional-integral control and the like are individually performed so that the respective input deviations are minimized, and the D-axis voltage command and the Q-axis voltage command are output, respectively. This is given to the inverse converter 66. In the Cartesian coordinate inverse converter 66, the given D-axis voltage command and Q-axis voltage command are subjected to Cartesian coordinate inverse transform using the DQ phase θ as a reference phase, and the obtained voltage command is input to the PWM circuit 67. In this case, as described below, since the actual current input to the A axis is subjected to orthogonal coordinate transformation and inverse transformation using the same DQ phase θ, this voltage command is for the A axis in the same phase as the actual current. It becomes only. The PWM circuit 67 performs pulse width modulation by comparing the voltage command with the triangular wave carrier, generates a gate pulse signal, sends it to the inverter main circuit 5, and controls the output voltage of the single-phase inverter 21.

  Here, the orthogonal coordinate transformation will be briefly described. The Cartesian coordinate converter 68 has A and B as input terminals, D and Q as output terminals, and DQ phase θ as a reference phase. Perform coordinate conversion to (DQ conversion).

D = Acosθ + Bsinθ (1)
Q = -Asinθ + Bcosθ (2)
Then, the orthogonal coordinate inverse converter 66 performs coordinate conversion (inverse DQ conversion) from the orthogonal rotation coordinate to the orthogonal fixed coordinate by the following equations (3) and (4) using the same DQ phase θ as a reference phase.

A = Dcosθ-Qsinθ (3)
B = Dsinθ + Qcosθ (4)
The DQ phase θ is determined as follows.

  First, since the electrical phase of each winding of the multiphase motor 1 has a certain phase difference according to the design of the multiphase motor 1, the phase of the current to be passed through each winding, that is, each phase is The waveform is shifted by this phase difference for each phase. For example, in the case of a typical multi-phase motor having 20 phases, the phase difference = 360/20 = 18 degrees, and it is only necessary to apply a current whose phase is shifted by 18 degrees to each phase. Therefore, it is induced by adding the correction phase peculiar to the single phase inverter 21 determined by the interphase phase difference correction circuit 70 to the electrical angle given from the electrical angle calculation circuit 34 of the speed control device 3 by the adder 69. The voltage phase is obtained and used as the reference DQ phase. However, in the case of the first embodiment, the induced voltage phase is advanced by π by the adder 71 to obtain the reference DQ phase. This is to match the sign with the calculation method used for DQ conversion of a general three-phase inverter.

  Next, input of the orthogonal coordinate converter 68 will be described. An actual current that is an AC amount detected by the current detector 51 is applied to the A terminal of the orthogonal coordinate converter 68. A current having a phase that is equal and orthogonal to the current command vector, which is the command value of the actual current, is applied to the B terminal of the orthogonal coordinate converter 68. For this reason, the current advance angle is added by the adder 72 to the DQ phase which is the output of the adder 71, the cosine (cos) is taken by the cosine calculator 73, and the output is taken as the D-axis current command and the Q-axis current. A virtual cosine wave is generated by multiplying the current command amplitude obtained from the command by the amplitude calculator 74 and the multiplier 75. As long as the virtual cosine wave is obtained so as to be equal to the amplitude of the current command vector and orthogonal to the phase of the current command vector, another calculation method such as using a current amplitude command input from a host device may be used. Also, a virtual cosine wave may be generated using information on the amplitude and phase of the actual current. Ideally, it is better to use the amplitude and phase of the actual current. However, in order to extract the amplitude and phase information from the single-phase alternating current value, a correspondingly complicated calculation process is required. In a steady state where the control is good, the amplitude and phase of the current command vector can be sufficiently substituted, so it can be said that the configuration using the current command vector is more realistic.

  In the above configuration, when the multiphase motor 1 is a synchronous motor, an actual current synchronized with the rotational phase of the multiphase motor 1 flows in each winding in a steady state. Even if the multiphase motor 1 is an induction motor, by integrating the primary side frequency obtained by adding the slip frequency to the rotation frequency of the motor to obtain the rotation angle, this angle is the current phase angle to be energized and Therefore, it is possible to control with the same configuration as in this embodiment. The current phase of this embodiment uses the phase of the current command vector, but it may be a phase obtained by correcting the phase error or fluctuation of the actual current.

  In the first embodiment, the reference phase applied to the current command calculator 61 is the current advance angle. In this case, the DQ phase, which is the reference phase of the orthogonal coordinate converter 68 and the orthogonal coordinate inverse converter 66, is used as the induced voltage phase, so that the current command vector is converted into the true D axis and the true Q axis as shown in FIG. It has become possible to perform so-called feedback current control for these two axes.

  FIG. 4 introduces the generalized concept of the control D axis and the control Q axis, and the current vector when the control DQ axis is a phase advanced by the rotation phase correction angle with respect to the true DQ axis. This shows the phase relationship. Since the current advance angle is the advance angle of the current vector from the true Q axis, in this case, the reference phase given to the current command calculator 61 is a phase angle obtained by subtracting the rotational phase correction angle from the current advance angle. At this phase angle, the current command vector is developed on the control D axis and the control Q axis to obtain the D axis current command and the Q axis current command. In order to match the current phase on the feedback side with these, the DQ phase which is a reference phase given to the orthogonal coordinate converter 68 and the orthogonal coordinate inverse converter 66 is set to the interphase phase difference correction circuit 70 with respect to a given common electrical angle. A value obtained by further adding the rotational phase correction angle to the induced voltage phase obtained by adding the individually shifted phase angles determined in (1). In this manner, the true D axis and the true Q axis can be controlled by the DQ axis shifted by the rotation phase correction angle. In the first embodiment, the control DQ axis and the true DQ axis coincide with each other. A case where the current advance angle and the rotational phase correction angle coincide will be described in the second embodiment.

  According to the first embodiment, since all of the D-axis current, the Q-axis current, and the current amplitude command are DC amounts, the actual current phase error and amplitude error with respect to the current command vector do not occur. If the phase error can be suppressed, an actual current can be passed according to the current command vector, so that the current waveform can be improved and the power factor can be improved. Details of the power factor improvement will be described in Example 3. Since each single-phase inverter performs DQ conversion individually, even if several of the single-phase inverters are stopped, the operation can be continued by performing stable current control with the remaining single-phase inverters. Moreover, since current control is performed individually for each single-phase inverter, the apparatus can be simplified. Furthermore, when the conventional multiphase motor driving device as shown in Patent Document 1 is changed to the method of the present invention, it is only necessary to change the circuit in the control device, so that it can be easily replaced.

  FIG. 5 is a block diagram of a multiphase motor driving apparatus according to Embodiment 2 of the present invention. In the second embodiment, the same parts as those in the block configuration diagram of the multiphase motor driving device according to the first embodiment of the present invention shown in FIG. The second embodiment is different from the first embodiment in that the current command calculator 61 is omitted, the amplitude calculator 74 is omitted according to this, and the Q-axis current command is directly supplied to the multiplier 75. The induced voltage The current advance angle is added to the phase by the adder 76 to obtain a current phase, which is added to the adder 71, and the adder 72 is omitted and the DQ phase is added to the cosine calculator 73 as it is.

  In FIG. 4, when the current advance angle and the rotational phase correction angle are set to be equal, the current vector and the control Q-axis direction coincide. The D-axis current command is always 0. Since the reference phase given to the current command calculator 61 becomes 0 by subtracting the rotational phase correction angle from the current advance angle, the current command calculator 61 becomes unnecessary, and the current amplitude command becomes the magnitude of the Q-axis current command as it is. . Then, control on the control DQ axis is possible in a state where 0 is always given to the D-axis current command. In this case, as shown in FIG. 5, the DQ phase θ is set as the reference phase obtained by adding the current advance angle to the induced voltage phase described in the first embodiment, and the current phase on the feedback side is matched with the command side. Since the current command calculator 61 is not necessary, the adder 72 is not necessary.

  According to the second embodiment, the D-axis current has only to be controlled to 0 at all times, so that the control can be simplified while maintaining the effects described in the first embodiment.

  FIG. 6 shows a generalized upper level control device corresponding to the speed control device 3 in FIG. A torque command is input to the host control device 3A instead of a speed command. Corresponding to this torque command, the table 36 is referenced to output a current amplitude command. The table 36 stores data of various constants and various characteristics of the multiphase motor 1. That is, when a torque command is given, in addition to realizing the given torque, a current amplitude command that matches other conditions is selected and output. Note that the current amplitude command in this case may be directly output as a current command decomposed on the DQ axis.

  The current phase calculation circuit 35 refers to the given torque command and data in the table 36, and outputs a current advance angle that matches a desired condition. The current phase calculation circuit 35 is given rotational speed information by the speed detection circuit 31.

  FIG. 7 is a vector diagram for explaining how to set the current advance angle in order to set the output power factor of the single-phase inverter 21 to 1. FIG. Assuming that the output voltage of the single-phase inverter 21 is V, this voltage V is a reactance drop orthogonal to the current drop I caused by the resistance I of the circuit and winding and the current drop I caused by the reactance L of the circuit and winding. This is a vector addition of the minute ωLI and the induced voltage due to the magnet. Therefore, the current lead angle is changed while maintaining the above relationship. As shown in FIG. 7, when the voltage V and the current I are in phase, the output power factor of the single-phase inverter 21 is 1, so the current advance angle at this time is a value to be obtained. In the case of FIG. 7, if the DQ axis is the true DQ axis, the Q axis component of the current I corresponds to the torque component of the torque command or current amplitude command. It becomes possible to control the output power factor of the single-phase inverter 21 to 1 under a speed condition determined by ωLI.

  FIG. 8 shows a method for determining a current operating point by an isotorque line, a constant current circle, and a constant voltage ellipse in an embedded magnet type synchronous motor. The isotorque lines shown in FIG. 8 correspond to the data stored in the table 37. In the case of the embedded magnet type synchronous motor, there is a reluctance torque due to the saliency of the iron core in addition to the torque due to the permanent magnet. For example, (1) in FIG. 8 indicates that a desired torque can be output with a minimum current by selecting a contact point between a constant current circle of the current vector and an isotorque line as an operating point. In (2), the permanent magnet magnetic flux is weakened when the permanent magnet motor rotates at high speed and the induced voltage exceeds the inverter maximum output voltage by selecting the intersection of the constant voltage ellipse and the equal torque line as the operating point. This indicates that the magnetic flux can be controlled by flowing a current in the direction, and the motor can be operated at a higher speed. In this case, the magnitude of the current vector is output as a current amplitude command, and the corresponding current advance angle may be used as the current advance angle of the output of the current phase calculation circuit 36 as it is. In the case of (2), the host controller 3A is required to have a configuration for inputting a voltage command to be input to the PWM circuit 67, but the illustration is omitted.

  As mentioned above, although Example 1 thru | or Example 3 was demonstrated, these Examples are shown as an example and are not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  For example, in FIG. 1 and FIG. 5, the A-axis component shown in the equation (3) is used for the voltage command that is the output of the Cartesian coordinate inverse transformer 66, and in response to this, the Cartesian coordinate transformer 68 includes: Although the actual current is input as the A-axis component and the virtual cosine wave is input as the B-axis component, the B-axis component shown in the equation (4) is used as the voltage command, and the B-axis component of the orthogonal coordinate converter 68 is used. A configuration in which a virtual current cosine wave is input to the A-axis component is also possible. In short, a virtual cosine wave may be input as a current response as a component of an axis orthogonal to the axis that controls the actual current. Although described as “virtual cosine wave”, the difference between the cosine wave and sine wave is simply the difference in phase relationship. If a virtual wave can be created with a phase that matches the above phase relationship, cosine (cos) It is optional to use either (operation) / sine (sin operation).

  Further, although both the current advance angle and the rotational phase correction angle have been described as positive values, either one may be negative or both may be negative.

  Further, the table 36 and the current phase calculation circuit 35 shown in FIG. 6 may be integrated.

  Further, the current command calculator 61 in FIG. 1 is provided inside the control device 6, but is provided inside the speed control device 3, which is a higher-level control device, so that the D-axis current command and the Q-axis current command are sent to the single-phase inverter. 21 may be used.

DESCRIPTION OF SYMBOLS 1 Multiphase motor 21, 22, ... 2N Single phase inverter 3 Speed control apparatus 3A High-order control apparatus 4 Rotation angle detector 5 Inverter main circuit 6 Control apparatus 31 Speed detection circuit 32 Subtractor 33 Speed controller 34 Electrical angle calculation Circuit 35 Current phase calculation circuit 36 Table 51 Current detector 61 Current command calculator 62 Subtractor 63 D-axis current controller 64 Subtractor 65 Q-axis current controller 66 Orthogonal coordinate inverse converter 67 PWM circuit 68 Orthogonal coordinate converter 69 Adder 70 Interphase phase difference correction circuit 71 Adder 72 Adder 73 Cosine calculator 74 Amplitude calculator 75 Multiplier

Claims (8)

A multiphase motor having a plurality of phase windings insulated from each other;
A plurality of single-phase inverters connected to each of the windings and outputting AC power; and
It is composed of a host controller that gives a current amplitude command to the single-phase inverter,
The single-phase inverter is
A current detector for detecting an actual current flowing through the winding, and a control device for controlling a current flowing through the winding based on the current amplitude command;
The controller is
Current command calculation means for expanding the current amplitude command into two-axis current commands of control D axis and control Q axis ;
Virtual cosine wave generating means for generating a virtual cosine wave having a phase equal to the amplitude of the current amplitude command or the real current and having a phase orthogonal to the current amplitude command or the real current; and the real current and the virtual cosine wave Using orthogonal rotation coordinate conversion means for orthogonal rotation coordinate conversion using,
The current command of the two-axis obtained by the current command calculating means, the current component of the two-axis obtained by the orthogonal rotation coordinate conversion means performs a current control such that each track,
The reference phase of the orthogonal rotation coordinate conversion means is:
According to the phase difference of each winding of the multiphase motor, using the phase angle individually shifted by each single-phase inverter,
The direction of the field pole rotationally synchronized with the multiphase motor is the true D axis, the direction of the induced voltage by the field pole perpendicular to the true Q axis is the true Q axis, and the advance angle of the current vector from the true Q axis is the current advance angle. When
The reference phase of the orthogonal rotation coordinate conversion means is obtained by adding the individually shifted phase angle to a value obtained by converting the rotation angle detected by the rotation angle detector provided in the multiphase motor into an electrical angle, and further rotating Add the phase correction angle,
The reference phase of the current command calculation means is obtained by subtracting the rotational phase correction angle from the current advance angle . The multiphase motor drive device according to claim 1 , wherein the rotational phase correction angle is set to 0. The multiphase motor drive device according to claim 1 , wherein the current advance angle and the rotation phase correction angle are set to be equal values. The virtual cosine wave generating means includes
Adding the individually shifted phase angle to a value obtained by converting a rotation angle detected by a rotation angle detector provided in the multiphase motor into an electrical angle;
Further comprising a phase obtained by adding the current advance angle, according to the actual current or any one of claims 1 to 3, characterized in that to generate a virtual cosine wave having an amplitude of said current amplitude command Multiphase motor drive device. Multiphase motor driving device according to any one of claims 1 to 4, characterized in that the power factor of the single-phase inverter has set the current advance angle of phase to be 1. When the torque component of the current amplitude command and the torque command value for the torque command value, claim 1, characterized in that to set the current advance angle so that the amplitude of the current is minimized to be energized The multiphase electric motor drive device according to claim 4 . Said current when the torque component of the amplitude command and the torque command value, according to claim 1 to claim 4, characterized in that set for the torque command, the current advance angle as the motor terminal voltage becomes constant The multiphase motor drive device according to any one of the above. Having speed detecting means for detecting the speed of the multiphase motor;
The host controller is
Any one of claims 1 to 7 given speed command and the deviation of the velocity obtained by the detecting means speed is characterized in that so as to output the current amplitude command so as to minimize The multiphase motor drive device described in 1.

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