JP2020014350A - Polyphase motor drive device - Google Patents

Abstract

To provide a polyphase motor drive device capable of increasing output torque from a polyphase motor, by superposing a prescribed harmonic current with a desired phase.SOLUTION: An inverter part of a polyphase motor drive device adjusts AC power supply to each winding of a polyphase motor having winding of multiple phases insulated from each other. A control section adds an output value of a fundamental voltage command for controlling the output voltage of the inverter part so as to feed a fundamental wave current to the winding, and the output value of a harmonic voltage command for feeding a prescribed (2n+1) order harmonic current to the winding, and controls switching of the inverter part by a sum thereof. A harmonic wave control section determines the (2n+1) order harmonic wave component of the current fed to the winding, on the basis of the current command of the fundamental wave, and determines the current phase of the (2n+1) order harmonic wave component so as to feed the current of the (2n+1) order harmonic wave component to the winding with a phase matching the phase of the (2n+1) order harmonic wave component contained in an induction voltage of the polyphase motor.SELECTED DRAWING: Figure 1A

Description

  Embodiments of the present invention relate to a polyphase motor drive device.

  The multi-phase motor driving device drives the multi-phase motor using a plurality of single-phase inverters. A polyphase motor includes a plurality of windings that are electrically insulated from each other. The multi-phase motor is driven by supplying AC power to each winding from each single-phase inverter. The induced voltage of other polyphase motors may include harmonic components. There has been a demand to increase the output torque of the multi-phase motor using such a harmonic voltage component.

JP 2015-126585 A

In order to efficiently use the harmonic induced voltage component of the polyphase motor, there is a problem that the harmonic current must be superimposed on the fundamental current in accordance with the harmonic induced voltage phase.
SUMMARY OF THE INVENTION An object of the present invention is to provide a multi-phase motor driving device capable of further increasing the output torque of a multi-phase motor by superimposing a predetermined harmonic current at a desired phase.

  A polyphase motor driving device according to one aspect of an embodiment includes an inverter unit and a control unit. The inverter adjusts the supply of the AC power to the multi-phase motor by controlling the output of the AC power to each winding of the multi-phase motor having the multi-phase windings insulated from each other. The control unit controls the inverter unit. The control unit includes a fundamental voltage command generation unit, a harmonic control unit, an adder, and a switching control unit. The fundamental wave voltage command generation unit generates a fundamental wave voltage command for controlling an output voltage of the inverter unit such that a fundamental wave current flows through the winding based on a current command of the fundamental wave. When n is defined as an arbitrary natural number, the harmonic control unit generates a harmonic voltage command for flowing a predetermined 2n + 1st harmonic current through the winding. The adder adds the output value of the fundamental voltage command and the output value of the harmonic voltage command. The switching control unit switches the inverter unit according to the output value of the adder. The harmonic control unit includes a harmonic current generator and a phase angle offset generator. The harmonic current generator determines a 2n + 1 order harmonic component of a current flowing through the winding based on a current command of the fundamental wave. The phase angle offset generator generates a 2n + 1 order harmonic component so that a current of the 2n + 1 order harmonic component flows through the winding at a phase matched with the phase of the 2n + 1 order harmonic component included in the induced voltage of the polyphase motor. Is determined.

FIG. 1 is a configuration diagram of a polyphase motor driving device according to a first embodiment. FIG. 3 is a configuration diagram of an odd-order harmonic control unit according to the first embodiment. FIG. 3 is a diagram for explaining a phase relationship between an induced voltage and a current of the multiphase motor according to the first embodiment. FIG. 4 is a vector diagram for explaining a phase relationship between current vectors according to the first embodiment. FIG. 4 is a vector diagram for explaining a phase relationship between current vectors using the concept of a control D axis and a control Q axis according to the first embodiment. FIG. 2 is a configuration diagram of a harmonic current command generator according to the first embodiment. FIG. 4 is a diagram for describing a combination of a fundamental wave and harmonics of each order according to the first embodiment. FIG. 4 is a configuration diagram of a polyphase motor driving device according to a second embodiment. FIG. 9 is a configuration diagram of an odd-order harmonic control unit according to the second embodiment.

  Hereinafter, a variable-speed polyphase motor driving device according to an embodiment will be described with reference to the drawings. In the following description, the variable-speed multi-phase motor driving device is simply referred to as a multi-phase motor driving device. Also, components having the same or similar functions are denoted by the same reference numerals. In addition, overlapping descriptions of those configurations may be omitted. Note that being electrically connected may be simply referred to as “connected”. The “fundamental wave” shown in the following description refers to a component having the lowest frequency among signal components synchronized with the rotation frequency of the polyphase motor. The “2n + 1 order harmonic component” is a harmonic component with respect to the frequency of the fundamental wave. Unless otherwise specified, an odd one or a plurality of orders included in any of current, voltage, and power. It is a harmonic component. Although a rectangular coordinate system is illustrated as a coordinate system related to coordinate conversion, the coordinate system is not limited to this, and may be replaced with a coordinate system having two axes that can independently handle components of two axes. It should be noted that the case of "equal in size" includes the case of being substantially equal.

(First embodiment)
FIG. 1A is a configuration diagram of the polyphase motor driving device of the embodiment.
FIG. 1A shows a polyphase motor 1, a polyphase motor driving device 2, a speed control device 3, and a rotation angle detector 4 (PS).

  The polyphase motor drive device 2 includes single-phase inverters 21, 22,..., 2M. The multi-phase motor driving device 2 drives the multi-phase motor 1 by operating the single-phase inverters 21, 22,..., 2M, respectively.

  The multi-phase motor 1 includes a plurality of windings (not shown) corresponding to each phase, and the windings are electrically insulated from each other. Each winding is connected to the output of each of the single-phase inverters 21, 22,..., 2M. The multi-phase motor 1 is driven by supplying AC power to each winding from the single-phase inverters 21, 22,..., 2M. Hereinafter, an example in which the field of the multi-phase motor 1 is a permanent magnet type will be described. However, an electromagnet type may be used instead. It is good to replace with the direction. A rotation angle detector 4 is attached to a shaft of the polyphase motor 1. The output of the rotation angle detector 4 is connected to the input of the speed control device 3. The rotation angle detector 4 detects the mechanical angle of the shaft of the multi-phase electric motor 1 and supplies the detected mechanical angle to the speed control device 3.

  The speed controller 3 is provided commonly to the single-phase inverters 21, 22,..., 2M, and receives a speed command transmitted from a higher-level controller (not shown). This speed command may change over time. The speed controller 3 sends the fundamental current command ICOM to each of the single-phase inverters 21, 22,..., 2M. Each of the single-phase inverters 21, 22,..., 2M allows an alternating current according to the fundamental current command ICOM to flow through the windings of the multi-phase motor 1. M is, for example, a natural number of 2 or more.

  The speed control device 3 includes, for example, a speed detection circuit 31 (d / dt), a subtracter 32, a speed controller 33 (PI), an electrical angle calculation circuit 34, and a current phase calculation circuit 35. The mechanical angle output from the rotation angle detector 4 is supplied to the input of the speed detection circuit 31. The speed detection circuit 31 derives the actual speed by differentiating the mechanical angle supplied from the rotation angle detector 4. The first input of the subtractor 32 is supplied with the above speed command from the outside, the output of the speed detection circuit 31 is connected to the second input, and the input of the speed controller 33 is connected to the output. The subtracter 32 calculates a speed deviation between a speed command supplied to the first input and an actual speed supplied from the speed detection circuit 31 to the second input, and supplies the speed deviation to the speed controller 33. The speed controller 33 derives a fundamental current command ICOM by using the speed deviation by proportional integration control or the like so that the output signal of the speed detection circuit 31 follows a speed command from the outside. The input of the electrical angle calculation circuit 34 is connected to the output of the rotation angle detector 4. The electrical angle calculation circuit 34 derives an electrical angle from a mechanical angle based on the number of poles of the multi-phase motor 1. The input of the current phase calculation circuit 35 is connected to the output of the speed controller 33. The current phase calculation circuit 35 derives, based on the fundamental wave current command ICOM, a current lead angle of the winding current of the multi-phase motor 1 according to one of the fundamental wave current command ICOM and its torque component. The output of the speed controller 33, the output of the electrical angle calculation circuit 34, and the output of the current phase calculation circuit 35 are connected to the inputs of the single-phase inverters 21, 22,..., 2M, respectively. As described above, the speed control device 3 can adjust the current lead angle with respect to the induced voltage phase of the multi-phase motor 1.

  Next, the single-phase inverters 21, 22,..., 2M will be described. The inputs of the single-phase inverters 21, 22,..., 2 M are input to the fundamental wave current command ICOM from the speed controller 33, the electric angle from the electric angle calculation circuit 34, and the current from the current phase calculation circuit 35. Information relating to the lead angle is supplied. The single-phase inverters 21, 22,..., 2M output AC power to each winding of the multi-phase motor 1 having a plurality of windings that are insulated from each other, based on at least the above information. Since the basic configurations of the single-phase inverters 21, 22,..., 2M are the same, the single-phase inverter 21 will be described as an example. The single-phase inverter 21 includes an inverter main circuit 5 (inverter unit) and a control unit 6.

  The inverter main circuit 5 is, for example, a bridge circuit in which a plurality of switching elements are combined, converts DC voltage into AC, and supplies AC power to the windings of the corresponding polyphase motor 1. The inverter main circuit 5 controls the supply of AC power to the multi-phase motor 1 by control. For example, the output of the inverter main circuit 5 is connected to the polyphase motor 1 via a cable. A current detector 51 is provided on an electric circuit connecting the inverter main circuit 5 and the polyphase motor 1. The current detector 51 detects a current flowing between the inverter main circuit 5 and the multi-phase motor 1 and supplies a value of an actual current as a result of the detection to the control unit 6. In the following description, the value of the actual current may be simply referred to as the actual current.

  Control unit 6 adjusts the current that inverter main circuit 5 causes to flow through the windings of multiphase motor 1 based on fundamental wave current command ICOM. The control unit 6 includes, for example, a fundamental voltage command generation unit 60, an adder 65, a PWM circuit 66 (PWM), and a harmonic control unit 91. Note that the PWM circuit 66 is an example of a switching control unit.

  The fundamental wave voltage command generator 60 includes a current command calculator 61A, subtracters 62A and 62B, a D-axis current controller 63A, a Q-axis current controller 63B, a rectangular coordinate inverse converter 64, and an adder 69. , 71, 72, a rectangular coordinate converter 67, a low-pass filter 68A, 68B (LPF), an inter-phase difference correction circuit 70, a cosine calculator 73 (cos), an amplitude calculator 74, and a multiplier. 75.

  The input of the current command calculator 61A is connected to the output of the speed controller 33 in the speed controller 3, and the fundamental wave current command ICOM is supplied from the speed controller 3. The current command calculator 61A adjusts the reference value of the current flowing through the winding by the inverter main circuit 5 based on the fundamental wave current command ICOM.

  For example, the current command calculator 61A expands the fundamental wave current command ICOM supplied from the speed control device 3 on the orthogonal rotation coordinates based on the current advance angle, and the component in the true D-axis direction and the component orthogonal to the true D-axis direction. It is divided into components in the true Q-axis direction. The component in the true D-axis direction is defined as a D-axis current command, and the component in the true Q-axis direction is defined as a Q-axis current command.

  For example, this fundamental wave current command ICOM is regarded as a current command vector advanced in phase by the current advance angle from the true Q axis, and the current command vector is projected on the true D axis and the true Q axis. Here, the direction of the magnetic flux vector of the permanent magnet, which is the field pole of the multi-phase motor 1, is the true D axis, and the direction of the induced voltage vector by the field pole orthogonal thereto is the true Q axis. In this case, the direction of the vector of the current flowing through the winding of the multi-phase motor 1 is a direction in which the phase is advanced from the true Q axis by the current advance angle. This phase relationship is shown in FIGS. FIG. 2 is a diagram for explaining the phase relationship between the induced voltage and the current of the polyphase motor of the embodiment. FIG. 3 is a vector diagram for explaining a phase relationship between current vectors according to the embodiment. 2A shows the induced voltage waveform, FIG. 2B shows its phase, FIG. 2C shows the current waveform, and FIG. 2D shows the current phase. This shows that the current phase is a phase advanced by the current advance angle with respect to the induced voltage phase. If this is represented by DQ orthogonal rotation coordinates, FIG. 3 is obtained. That is, the phase of the current command vector is advanced by the current advance angle with respect to the induced voltage having the same phase as the Q-axis current. Note that the vector diagram shown in FIG. 3 also shows an actual operation state controlled as instructed as described below, and in this case, the current command vector is simply referred to as a current vector in the sense of also showing the actual current. .

  The two outputs of the current command calculator 61A are respectively connected to the first input of the subtractor 62A and the first input of the subtractor 62B, and each of them is connected to the input of the amplitude calculator 74. The current command calculator 61A supplies a D-axis current command to a first input of a subtractor 62A, and supplies a Q-axis current command to a first input of a subtractor 62B. A second input of the subtractor 62A is connected to an output of the low-pass filter 68A. A second input of the subtractor 62B is connected to an output of the low-pass filter 68B.

  The inputs of the low-pass filters 68A and 68B are respectively connected to the D-axis output and the Q-axis output which are the output terminals of the orthogonal coordinate converter 67, and the outputs thereof are the second outputs of the subtracters 62A and 62B. The input and the input of the harmonic controller 91 are connected to each other. The low-pass filters 68A and 68B transmit low-frequency components of signals output from the D-axis output and the Q-axis output of the orthogonal coordinate converter 67, respectively.

  The subtracter 62A subtracts the D-axis current supplied from the orthogonal coordinate converter 67 via the low-pass filter 68A from the D-axis current command supplied from the current command calculator 61A. The subtracter 62B subtracts the Q-axis current supplied from the orthogonal coordinate converter 67 via the low-pass filter 68B from the Q-axis current command supplied from the current command calculator 61A. The output of the subtractor 62A is connected to the input of the D-axis current controller 63A. The subtractor 62A supplies the output value to the input of the D-axis current controller 63A. The output of the subtractor 62B is connected to the input of the Q-axis current controller 63B. The subtractor 62B supplies the output value to the input of the Q-axis current controller 63B. The D-axis current controller 63A uses the output signal of the subtractor 62A to generate a D-axis voltage command by proportional integration control or the like so that the D-axis current follows the D-axis current command. The Q-axis current controller 63B uses the output signal of the subtractor 62B to generate a Q-axis voltage command by proportional integration control or the like so that the Q-axis current follows the Q-axis current command. An output of the D-axis current controller 63A is connected to a D-axis input which is an input terminal of the orthogonal coordinate inverse transformer 64. The D-axis current controller 63A supplies the D-axis voltage command to the D-axis input of the orthogonal coordinate inverse converter 64. An output of the Q-axis current controller 63B is connected to a Q-axis input which is an input terminal of the orthogonal coordinate inverse transformer 64. The Q-axis current controller 63B supplies a Q-axis voltage command to the Q-axis input of the orthogonal coordinate inverse transformer 64. The orthogonal coordinate inverse converter 64 performs the orthogonal coordinate inverse conversion of the D-axis voltage command and the Q-axis voltage command supplied from the D-axis current controller 63A and the Q-axis current controller 63B, respectively, using the DQ phase θ as a reference phase. .

  The fundamental voltage command generator 60 configured as described above controls the output voltage of the inverter main circuit 5 based on the fundamental current command ICOM so that the fundamental current flows through the windings of the multi-phase motor 1. To generate a fundamental wave voltage command for

  A first input of the adder 65 is connected to an output A of the orthogonal coordinate inverse transformer 64, a second input of the adder 65 is connected to an output of the harmonic controller 91, and an output of the adder 65 is a PWM circuit. 66. The orthogonal coordinate inverse transformer 64 supplies the derived main voltage command to the PWM circuit 66 via the adder 65. In the above case, the orthogonal coordinate inverse converter 64 converts the components into the A-axis component and the B-axis component of the orthogonal fixed coordinate system based on the D-axis voltage command and the Q-axis voltage command. The main voltage command is an A-axis component having the same phase as the actual current detected by the current detector 51. As will be described later, the orthogonal coordinate converter 67 converts the actual current supplied to the A-axis based on the DQ phase θ. The orthogonal coordinate inverse converter 64 performs the above inverse conversion using the same reference phase as the DQ phase θ, thereby converting the A-axis component into the above main voltage command.

  The PWM circuit 66 switches the inverter main circuit 5 based on the output value of the adder 65 by PWM control or the like. For example, the PWM circuit 66 performs a pulse width modulation by comparing the main voltage command with the triangular wave carrier, generates a gate pulse signal, supplies the gate pulse signal to the inverter main circuit 5, and outputs the output of the single-phase inverter 21. Control the voltage. The second input of the adder 65 is supplied with a combined harmonic correction command from the harmonic controller 91. Details of this will be described later.

  Here, the orthogonal coordinate conversion will be briefly described. There are two types of orthogonal coordinate conversion: a DQ conversion that is a forward conversion and an inverse DQ conversion that is an inverse conversion.

  The DQ conversion will be described using the orthogonal coordinate converter 67 as an example. The orthogonal coordinate converter 67 has an A-axis input and a B-axis input as input terminals, a D-axis output and a Q-axis output as output terminals, and a reference phase input. The orthogonal coordinate converter 67 uses the DQ phase θ supplied to the reference phase input as a reference phase, and performs coordinate conversion (DQ conversion) from the fixed rectangular coordinates to the orthogonal rotating coordinates according to the following equations (1) and (2). Perform A detailed description of the orthogonal coordinate converter 67 will be described later.

D = Acosθ + Bsinθ (1)
Q = −A sin θ + B cos θ (2)

  The inverse DQ transform will be described by taking the orthogonal coordinate inverse transformer 64 as an example. The Cartesian coordinate inverse transformer 64 has a D-axis input as an input terminal, an A-axis output and a B-axis output as Q-axis input / output terminals, and a reference phase input. The orthogonal coordinate inverse transformer 64 uses the DQ phase θ supplied to the reference phase input as a reference phase and performs coordinate conversion (inverse DQ conversion) from the orthogonal rotation coordinates to the orthogonal fixed coordinates by the following equations (3) and (4). ). A detailed description of the orthogonal coordinate inverse transformer 64 will be described later.

A = Dcosθ−Qsinθ (3)
B = Dsinθ + Qcosθ (4)

For example, the DQ phase θ is determined as follows.
The axis of the magnetic flux generated by each winding of the multi-phase motor 1 has an angle determined by the design of the multi-phase motor 1. When the electrical phases of the windings of the multi-phase motor 1 are compared, a phase difference corresponding to the above-described angle occurs in the electrical phase of each winding. Assuming that the phases of the currents supplied to the respective windings, that is, the respective phases are made uniform, it is necessary to shift the phase of the current to be supplied to each phase by this phase difference for each phase.

  First, the reference phase (DQ phase θ) of each phase will be described. For example, the inter-phase difference correction circuit 70 supplies the value regarding the phase difference between the phases determined as described above, instead of each phase. The output of the phase difference correcting circuit 70 is connected to a first input of an adder 69. The inter-phase difference correction circuit 70 supplies a first input of the adder 69 with a correction phase relating to the phase difference of the phase. The second input of the adder 69 is connected to the output of the electrical angle calculation circuit 34 of the speed control device 3, and the output of the adder 69 is connected to the first input of the adder 71. The adder 69 adds a correction phase specific to the single-phase inverter 21 determined by the inter-phase difference correction circuit 70 to the electric angle supplied from the electric angle calculation circuit 34 of the speed control device 3 to generate an induced voltage. Deriving the phase. This induced voltage phase is used as a reference phase used for processing of each unit. The adder 71 generates a phase in which the induced voltage phase is advanced by π, and sets the generated phase as a reference DQ phase θ. This is to match the sign with the calculation method used for DQ conversion of a general three-phase inverter. As described above, the DQ phase θ of each phase is generated.

  Next, the orthogonal coordinate converter 67 will be described. The output of the current detector 51 is connected to the A-axis input of the orthogonal coordinate converter 67, and a value (actual current) indicating the amount of AC current detected by the current detector 51 is supplied. A virtual current value corresponding to the actual current is supplied to the B-axis input of the orthogonal coordinate converter 67. The orthogonal coordinate converter 67 performs DQ conversion based on the value of the actual current supplied to the A-axis input, the value of the virtual current supplied to the B-axis input, and the DQ phase θ supplied to the reference phase input. Is carried out.

  For example, a virtual current corresponding to the expected value of the actual current is defined, and a current command vector is defined based on the expected value of the actual current and the DQ phase θ. For example, the current command vector is specified by the magnitude of the fundamental current command ICOM and the phase information for the DQ phase θ. A virtual current having the same magnitude as the current command vector and having a phase orthogonal to the current command vector is defined. This virtual current value is supplied to the B-axis input of the orthogonal coordinate converter 67.

  For example, the output of the adder 71 is connected to the first input of the adder 72, and the DQ phase θ is supplied from the adder 72. The output of the current phase calculation circuit 35 is connected to the second input of the adder 72, and the current lead angle is supplied from the current phase calculation circuit 35. The output of the adder 72 is connected to the input of a cosine calculator 73. The adder 72 adds the current lead angle supplied from the current phase calculation circuit 35 to the DQ phase θ supplied from the adder 71, and supplies the result to the input of the cosine calculator 73. The cosine calculator 73 derives a cosine (cos) of the DQ phase θ to which the current lead angle has been added. A first input of a multiplier 75 is connected to an output of the cosine calculator 73.

  The first input and the second input of the amplitude calculator 74 are connected to two outputs of the current command calculator 61A, respectively, and the output of the amplitude calculator 74 is connected to the second input of the multiplier 75. ing. The amplitude calculator 74 derives the fundamental current command amplitude of the virtual fundamental current from the D-axis current command and the Q-axis current command output from the current command calculator 61A according to the following equation (5), for example. .

  The multiplier 75 generates a virtual cosine wave by multiplying the fundamental current command amplitude derived by the amplitude calculator 74 by the cosine (cos) of the DQ phase θ to which the current lead angle is added. The cosine wave is supplied to the B-axis input of the orthogonal coordinate converter 67. The virtual cosine wave corresponds to the above-described virtual current value. The virtual cosine wave may have any amplitude as long as it is equal to the magnitude of the fundamental current command and is orthogonal to the phase of the vector of the fundamental current command. That is, the amplitude may be derived by another calculation method such as using the fundamental wave current command ICOM input from the host device. Alternatively, the phase of the virtual cosine wave may be generated by a method using information on the phase of the fundamental wave of the actual current.

  It is ideal to use the amplitude and phase of the actual current. However, extracting information on the amplitude and phase from the current value of the single-phase alternating current requires a correspondingly complicated calculation process. In a steady state in which the control is well performed, the above-described method using the current command vector can be used by using its amplitude and phase. The method using the current command vector has a simple configuration as described above, but can provide information necessary for the arithmetic processing. The virtual cosine wave generated in this manner is supplied to the B-axis input of the orthogonal coordinate converter 67.

  The harmonic controller 91 has its input connected to the two outputs of the orthogonal coordinate converter 67, the outputs of the low-pass filters 68A and 68B, and the output of the adder 71, respectively. 65 is connected to the second input. The harmonic control unit 91 generates an odd harmonic voltage command corresponding to the fundamental current command ICOM and the detected actual current, and generates a composite harmonic correction command based on the command.

  An example of the harmonic controller 91 according to the embodiment will be described with reference to FIG. 1B. FIG. 1B is a configuration diagram of the harmonic control unit 91 of the embodiment.

  The harmonic control unit 91 includes, for example, a harmonic current command generator 61B, a harmonic voltage generator 95, a phase angle offset generator 93, subtractors 76A and 76B, and an adder 94.

  The input of the harmonic controller 91 is connected to the two outputs of the orthogonal coordinate converter 67, the outputs of the low-pass filters 68A and 68B, the output of the speed controller 33, and the output of the adder 71, respectively. The output is connected to the second input of the adder 65.

  The first input of the subtractor 76A is supplied with the value of the D-axis current from the orthogonal coordinate converter 67, and the second input of the subtractor 76A is connected to the output of the low-pass filter 68A. The output is connected to a first input of a harmonic voltage generator 95. The first input of the subtractor 76B is supplied with the value of the Q-axis current from the orthogonal coordinate converter 67, and the second input of the subtractor 76B is connected to the output of the low-pass filter 68B. The output is connected to the second input of the harmonic voltage generator 95. The subtracter 76A derives a difference between the input and output of the low-pass filter 68A, and extracts an odd-order harmonic component excluding at least a fundamental wave. The subtracter 76B derives a difference between the input and output of the low-pass filter 68B, and extracts an odd-order harmonic component excluding at least a fundamental wave. The subtractor 76A and the subtractor 76B supply the respective differences described above, that is, the respective odd-order harmonic components to the harmonic voltage generator 95, respectively.

  The harmonic current command generator 61B has one input and a plurality of outputs. The fundamental current command ICOM is supplied to the input of the harmonic current command generator 61B. The harmonic current command generator 61B generates an odd harmonic current command corresponding to the order of a harmonic voltage generator 95, which will be described later, based on the fundamental current command ICOM. To supply. For example, the harmonic current command generator 61B outputs the third harmonic current command ICOM3 for the third harmonic, the fifth harmonic current command ICOM5 for the fifth harmonic, and the 2n + 1st harmonic current for the 2n + 1st harmonic. It generates and outputs a command ICOM2n + 1 and the like. Note that n is an arbitrary natural number. When these are collectively shown, they are referred to as odd-order harmonic current commands. The odd-order harmonic current command is for flowing a predetermined odd-order harmonic current (2n + 1st-order harmonic current) through the windings of the multi-phase motor 1. An example of the harmonic current command generator 61B is shown in FIG. 5, and details will be described later.

  The phase angle offset generator 93 has, for example, a plurality of outputs. The phase angle of the odd-order harmonic current component with respect to the phase of the fundamental wave is determined by the phase angle offset (harmonic offset angle) from the design data of the polyphase motor 1 or the induced voltage waveform when the polyphase motor 1 is rotated with no load. ). The phase angle offset generator 93 presets the phase angle offset of each order in accordance with the order of the harmonic voltage generator 95 described later, and supplies the phase angle offset to the harmonic voltage generator 95. For example, the phase angle offset generator 93 outputs the third harmonic offset angle θoffset3 with respect to the third harmonic, the fifth harmonic offset angle θoffset5 with respect to the fifth harmonic, and the 2n + 1st harmonic offset angle with respect to the 2n + 1st harmonic. θoffset2n + 1 and the like are generated and output. When these are collectively shown, they are called phase angle offsets. The magnitude of the phase angle offset is determined in accordance with the order.

  The harmonic voltage generator 95 has (3 + 2N) inputs and N outputs. Three of the (3 + 2N) inputs are supplied with the DQ phase θ and the output signals of the subtracters 76A and 76B. The output signals of the harmonic current command generator 61B and the output signal of the phase angle offset generator 93 are supplied to the remaining 2N inputs. For example, N is set to the number of harmonics having different orders.

  The harmonic voltage generator 95 includes harmonic generators 951, 952,..., 95N. For example, the harmonic generators 951, 952,..., 95N are assigned so as to generate third, fifth,.

  , 95N are the outputs of the subtractors 76A and 76B, the output of the harmonic current command generator 61B, the output of the phase angle offset generator 93, and the adder 71. And the output of the current phase calculation circuit 35 are connected in parallel.

  The difference output from the subtracters 76A and 76B and the DQ phase θ output from the adder 71 are given in parallel to the inputs of the harmonic generators 951, 952,. The odd-order harmonic command generated by the harmonic current command generator 61B and the phase angle offset generated by the phase angle offset generator 93 are independent of the inputs of the harmonic generators 951, 952,. Given to.

  , 95N are composed of odd-order harmonic components supplied from the subtractors 76A and 76B, odd-order harmonic commands supplied from the harmonic current command generator 61B, and phases. Based on the phase angle offset supplied from the angle offset generator 93 and the DQ phase θ, third-order, fifth-order,..., 2n + 1-order harmonic voltage commands are respectively generated. Note that each of the above harmonic voltage commands may be obtained by adding a phase difference corresponding to a phase angle offset to the DQ phase θ. The magnitude of the phase difference can be predetermined in design. Alternatively, it can be obtained from the induced voltage when the multi-phase motor 1 is rotated with no load as described above. The details of the harmonic generators 951, 952,..., 95N will be described later.

  The outputs of the harmonic generators 951, 952,..., 95N are connected to the respective inputs of the adder 94, respectively. The adder 94 adds the third-order, fifth-order,..., 2n + 1-order harmonic voltage commands supplied from the harmonic generators 951, 952,. It is supplied to the adder 65 as a combined harmonic correction command.

  Since the basic configuration of the harmonic generators 951, 952,..., 95N included in the harmonic voltage generator 95 is the same, the harmonic generator 951 will first be described as an example.

  The harmonic generator 951 includes a rectangular coordinate converter 77, subtractors 78A and 78B, harmonic current controllers 79A and 79B, a rectangular coordinate inverse converter 80, a second-order DQ phase calculator 811, and a third-order It includes a DQ phase calculator 821 and adders 89A and 89B.

  The harmonic generator 951 generates a third harmonic voltage command. The input of the second-order DQ phase calculator 811 is connected to the output of the adder 71, and the output is connected to the first input of the adder 89A. The second-order DQ phase calculator 811 outputs a signal obtained by multiplying the DQ phase θ by 2n. In the case of the second-order DQ phase calculator 811, the value of n is 1.

  A first input of the adder 89A is connected to an output of the second-order DQ phase calculator 811. An output of the adder 89A is connected to a reference phase input of the orthogonal coordinate converter 77. A first input of the adder 89B is connected to a reference phase input of the third-order DQ phase calculator 821, and an output terminal of the adder 89B is connected to a reference phase input of the orthogonal coordinate inverse transformer 80. The second inputs of the adders 89A and 89B are connected to the output of the corresponding harmonic order among the plurality of outputs of the phase offset generator 93.

  The adder 89A adds the value of the third harmonic offset angle θoffset3 supplied from the phase angle offset generator 93 to the value of 2nθ obtained by multiplying the DQ phase θ supplied from the secondary DQ phase calculator 811 by 2n. Then, the sum is output as a signal of the reference phase of the orthogonal coordinate converter 77. The adder 89B adds the value of the third harmonic offset angle θoffset3 supplied from the phase angle offset generator 93 to the value of 2nθ + θ obtained by multiplying the DQ phase θ supplied from the third DQ phase calculator 821 by 2n + 1 times. Then, the sum is output as a signal of the reference phase of the orthogonal coordinate inverter 80.

  The orthogonal coordinate converter 77 has an A-axis input, a B-axis input, a D-axis output, a Q-axis output, and a reference phase input. The outputs of the subtracters 76A and 76B are connected to the A-axis input and the B-axis input of the orthogonal coordinate converter 77, respectively, and the deviations output from the subtracters 76A and 76B are supplied. A signal obtained by doubling the DQ phase θ from the secondary DQ phase calculator 811 is supplied to the reference phase input of the orthogonal coordinate converter 77 via the adder 89A. As described above, the signal obtained by doubling the DQ phase θ supplied to the reference phase input of the orthogonal coordinate converter 77 via the adder 89A has the third harmonic offset angle θoffset3 with respect to the DQ phase θ. .

  Based on the output signal of the subtractor 76A supplied to the A-axis input and the output signal of the subtractor 76B supplied to the B-axis input, the orthogonal coordinate converter 77 supplies the signal to the reference phase input via the adder 89A. DQ conversion is performed based on the signal obtained by doubling the DQ phase θ to be performed, and the result is output from the D-axis output and the Q-axis output, respectively. By combining the DQ conversion by the orthogonal coordinate converter 77 and the DQ conversion by the orthogonal coordinate converter 67, as in the case where the DQ conversion is performed on the basis of a signal in which the DQ phase θ is tripled with respect to the actual current, The component of the third harmonic included in the actual current is converted to DC. That is, the output of the orthogonal coordinate converter 77 is a D-axis component and a Q-axis component obtained by projecting the 2n + 1-order harmonic current included in the actual current onto orthogonal rotation coordinates rotating at a frequency of 2n + 1 times. The reason why the output of the second-order DQ phase calculator 811 is doubled, not tripled, is that the fundamental component becomes a DC component by the DQ conversion of the equations (1) and (2). It is. In other words, the order of each frequency component is reduced by one step by the conversion by the orthogonal coordinate converter 67, so that the signal supplied from the orthogonal coordinate converter 67 to the input of the orthogonal coordinate converter 77 is the output signal of the current detector 51. This is because the 2n + 1 order harmonic component included in a certain actual current becomes a frequency component 2n times the fundamental wave.

  A first input of the subtractor 78A is connected to a D-axis output of the orthogonal coordinate converter 77, and an output of the subtractor 78A is connected to an input of the harmonic current controller 79A. A first input of the subtractor 78B is connected to a Q-axis output of the orthogonal coordinate converter 77, and an output of the subtractor 78B is connected to an input of the harmonic current controller 79B. The second input of the subtractor 78A is supplied with zero or a minute value, and the second input of the subtractor 78B is connected to, for example, the output corresponding to the third harmonic current command ICOM3 of the harmonic current command generator 61B. Have been.

  The harmonic current controller 79A performs a proportional-integral control or the like on the output value of the subtractor 78A, and issues a D-axis voltage correction command so that the first input signal of the subtractor 78A follows the second input signal of the calculator 78A. Generate The subtractor 78B subtracts the output value from the Q-axis output of the orthogonal coordinate converter 77 from the value of the third harmonic current command, which is one of the output values of the harmonic current command generator 61B, and calculates the difference. It is supplied to the input of the harmonic current controller 79B. The harmonic current controller 79B performs, for example, proportional integral control on the output value of the subtractor 78B, so that the Q-axis output of the orthogonal coordinate converter 77 follows the value of the third harmonic current command ICOM3. Generate a correction command.

  The orthogonal coordinate inverse converter 80 has a D-axis input, a Q-axis input, an A-axis output, a B-axis output, and a reference phase input. The output of the harmonic current controller 79A is connected to the D-axis input of the orthogonal coordinate inverse converter 80, and a D-axis voltage correction command is supplied from the harmonic current controller 79A. The output of the harmonic current controller 79B is connected to the Q-axis input of the orthogonal coordinate inverse converter 80, and a Q-axis voltage correction command is supplied from the harmonic current controller 79B. The orthogonal coordinate inverse converter 80 performs DQ inverse conversion on the basis of a signal obtained by triple the DQ phase θ supplied from the tertiary DQ phase calculator 821 to the reference phase input via the adder 89B, and performs orthogonal transform. The coordinate system of the output value of the coordinate inverse transformer 80 is returned to the fixed coordinate system. As described above, the third harmonic offset angle θoffset3 with respect to the DQ phase θ is set in the signal obtained by triple the DQ phase θ supplied to the reference phase input via the adder 89B. The output value of the orthogonal coordinate inverter 80 includes a correction amount of the main voltage command for converting the third harmonic current included in the output of the inverter main circuit 5 into the third harmonic current command ICOM3. This is called a third harmonic voltage command. The A-axis output of the orthogonal coordinate inverse transformer 80 is connected to one of the inputs of the adder 94. The orthogonal coordinate inverse converter 80 supplies the output value to the adder 94.

  , 95N are the same as the above-described harmonic generator 951.

  The harmonic generator 952 includes a rectangular coordinate converter 77, subtractors 78A and 78B, harmonic current controllers 79A and 79B, a rectangular coordinate inverse converter 80, a fourth-order DQ phase calculator 812, and a fifth-order It includes a DQ phase calculator 822 and adders 89A and 89B.

  The harmonic generator 952 generates a fifth harmonic voltage command. The outline of the difference between the harmonic generator 952 and the harmonic generator 951 will be described. The value of n in the harmonic generator 952 is 2, the fourth-order DQ phase calculator 812 generates a signal quadrupled the DQ phase θ, and the fifth-order DQ phase calculator 822 sets the DQ phase θ to 5 Generate a doubled signal. The orthogonal coordinate converter 77 performs DQ conversion on the basis of a signal obtained by quadrupling the DQ phase θ supplied from the fourth-order DQ phase calculator 812 to the reference phase input. The orthogonal coordinate inverse converter 80 performs DQ inverse conversion based on a signal obtained by multiplying the DQ phase θ as a signal supplied from the fifth-order DQ phase calculator 822 to the reference phase input by five times, and performs orthogonal coordinate inverse conversion. The coordinate system of the output value of the converter 80 is returned to the fixed coordinate system. This output value includes a correction amount of the main voltage command for converting the fifth harmonic current included in the output of the inverter main circuit 5 into the fifth harmonic current command ICOM5. This is called a fifth harmonic voltage command.

  The harmonic generator 95N includes a rectangular coordinate converter 77, subtractors 78A and 78B, harmonic current controllers 79A and 79B, a rectangular coordinate inverse converter 80, a 2n-order DQ phase calculator 81N, and a 2n + 1-order. It includes a DQ phase calculator 82N and adders 89A and 89B.

  The harmonic generator 95N generates a 2n + 1 order harmonic voltage command. The outline of the difference between the harmonic generator 95N and the harmonic generator 951 will be described. The value of n in the harmonic generator 95N is a natural number. In the case of this embodiment, the value of n is 3 or more because there are the harmonic generators 951 and 952 in addition to the harmonic generator 95N. In this case, the 2n-order DQ phase calculator 81N generates a signal in which the DQ phase θ is multiplied by 2n, and the 2n + 1-order DQ phase calculator 82N generates a signal in which the DQ phase θ is multiplied by 2n + 1. The orthogonal coordinate converter 77 performs DQ conversion on the basis of a signal obtained by multiplying the DQ phase θ supplied from the 2nth-order DQ phase calculator 81N to the reference phase input by 2n times. The orthogonal coordinate inverse converter 80 performs a DQ inverse transform on the basis of a signal obtained by multiplying the DQ phase θ as a signal supplied from the 2n + 1 order DQ phase calculator 82N to the reference phase input by 2n + 1, and performs orthogonal coordinate inverse conversion. The coordinate system of the output value of the converter 80 is returned to the fixed coordinate system. This output value includes a correction amount of the main voltage command for changing the 2n + 1st harmonic current included in the output of the inverter main circuit 5 to the 2n + 1st harmonic current command ICOM2n + 1. This is called a 2n + 1 order harmonic voltage command.

  The input of the adder 94 is connected to the outputs of the harmonic generators 951, 952,..., 95N independently of each other, and the output is connected to the first input of the adder 65. The adder 94 adds the third-order, fifth-order,..., 2n + 1-order harmonic voltage commands supplied from the harmonic generators 951, 952,. The output is supplied to the adder 65 from the output thereof.

  FIG. 5 is a configuration diagram of the harmonic current command generator 61B of the embodiment. The harmonic current command generator 61B includes a harmonic current distributor 610 and multipliers 611a, 612a,..., 61Na.

  In the harmonic current distributor 610, a harmonic current coefficient for superimposing a harmonic current according to the fundamental current command ICOM is set in advance in accordance with the order of each harmonic. The harmonic current distributor 610 outputs harmonic current coefficients.

  The multipliers 611a, 612a,..., 61Na have a first input connected to the speed controller 3, a second input connected to the harmonic current distributor 610, and an output connected to the harmonic of the harmonic voltage generator 95. , 95N are connected respectively to the inputs of the generators 951, 952,..., 95N. The current command ICOM supplied from the speed controller 3 is distributed, and the distributed signals are supplied to first inputs of multipliers 611a, 612a,..., 61Na, respectively. A signal defining the current amplitude of each harmonic is individually supplied from the harmonic current distributor 610 to the second input of each of the multipliers 611a, 612a,. Each of the above multipliers multiplies the signal from the first input by the signal from the second input, and outputs the respective products. For example, in the case of the third harmonic, the multiplier 611a multiplies the current command ICOM by the third harmonic current value supplied from the harmonic current distributor 610, and multiplies the product by the harmonic voltage. Supply it to the generator 95. The same applies to the case of fifth or higher order.

  The harmonic current command generator 61B generates a harmonic current command of each order by multiplying a fundamental current command ICOM (fundamental current component) by a harmonic current coefficient of each order. Note that the harmonic current command generator 61B may change the harmonic current coefficient according to the fundamental frequency. The harmonic current command is determined in advance so that the ratio of the torque to the current effective value (torque / current effective value) is maximized. Alternatively, the harmonic current command generator 61B may detect a fundamental wave output current or power during operation and determine a harmonic current command according to the output.

  For example, the harmonic current command generator 61B determines the harmonic current amplitude such that the torque ratio to the current effective value (torque / current effective value) is maximized. Hereinafter, an example of a method for determining the harmonic current amplitude will be described. If the current waveform and the fundamental wave frequency during the operation are known, the amplitude or the effective value of the fundamental wave and the harmonic component can be obtained by performing a frequency analysis on the current waveform by a fast Fourier transform process or the like. Using the obtained fundamental wave effective value, harmonic effective value, and the like, the total current effective value Irms can be calculated according to the following equation (6).

  For example, the harmonic current command generator 61B derives the differential (partial differential) of (torque / current effective value) from the acquired torque or power using the following equation (7), and calculates the torque relative to the current effective value. The harmonic current amplitude may be determined so that the ratio (torque / current effective value) is maximized. For example, the harmonic current command generator 61B may perform the above-described optimization processing every time the current command is changed.

  In the above equation (7), (t-1) and t are identification information indicating before and after the change of the harmonic current. T represents torque.

  In the present embodiment, speed control is performed. If the torque is increased by injecting harmonics, the torque (fundamental wave current) required for speed control is reduced. The harmonic current command generator 61B detects the required change in the torque based on the differential value (change) of the equation (7). The harmonic current command generator 61B may adjust the injection amount of the harmonic so that, for example, the differential value (change amount) takes zero or a positive value. The data of the torque and the effective current value in the above equation (7) are time history data adjacent to each other, and are a pair of data sandwiching when the current command is changed.

  It should be noted that not only a pair of data sandwiched when the current command is changed, but also a result of statistical processing on a plurality of time history data sandwiched when the current command is changed may be used instead. For example, as an example of statistical processing, the harmonic current command generator 61B takes an average value of 100 pieces of time history data before and after changing the current command, and based on the average value data, The calculation of equation (7) may be performed. As a result, it is possible to reduce the influence of noise included in the instantaneous value and the transient response of control, and to improve the reliability of data in the evaluation of the optimum condition.

  Alternatively, the harmonic current command generator 61B holds the result of the optimization processing described above, and performs the harmonic processing based on the held result without performing the optimization processing every time the current command is changed. A wave current command may be generated. For example, the harmonic current command generator 61B may use a method proportional to the output value of the speed controller 33 instead of the derivation method according to the above equation (7). According to this, the harmonic current command of each order can be obtained without performing the arithmetic processing for the purpose of optimization as described above, so that the process for obtaining the harmonic current command of each order is simplified. Can be In particular, when the target harmonic includes a plurality of orders, the degree of freedom increases and the calculation load of the optimization process increases. Therefore, under conditions where optimization processing becomes difficult, the processing can be simplified by determining the harmonic current amplitude using the output value of the speed controller 33.

  Next, an example of a method for defining a current amplitude for each order of each harmonic will be described. For example, the harmonic current distributor 610 outputs the ratio of each-order harmonic no-load magnetic flux to the fundamental-wave no-load magnetic flux as a harmonic current coefficient that defines the current amplitude of each harmonic. In this case, the above ratio is determined based on the following equation.

  Here, equations (8) and (9) are used to derive the fundamental wave torque T1st and the n-th harmonic torque Tn, respectively.

T1st = P × Ψ1st × Iq1st (8)
Tn = P × Ψn × Iqn (9)

  In the above equations (8) and (9), P indicates the number of poles of the multi-phase motor 1, Ψ1st indicates the fundamental wave no-load magnetic flux, Iq1st indicates the Q-axis current of the fundamental wave, and Ψn indicates the nth order It shows the harmonic no-load magnetic flux, and Iqn shows the Q-axis current of the n-th harmonic. Equations (8) and (9) are obtained when the D-axis current of the fundamental wave and the D-axis current of the nth harmonic are set to 0. As shown in Expression (8), the fundamental wave torque T1st is a product of the number of poles P of the polyphase motor 1, the fundamental wave no-load magnetic flux Ψ1st, and the Q-axis current Iq1st of the fundamental wave. The case of the harmonic is the same as that of the fundamental wave.

  Next, equation (10) shows the relationship between the fundamental wave torque T1st, the nth harmonic torque Tn, and the total output torque T. As shown in equation (10), the total output torque T is the sum of the fundamental torque T1st and the nth harmonic torque Tn.

T = T1st + Tn (10)

  Expression (11) shows an expression for determining the ratio kn of each order harmonic unloaded magnetic flux to the fundamental unloaded magnetic flux using the relationship shown in the above Expressions (8) to (10). .

kn = {n} 1st (11)

  For example, in the case of the third harmonic, the multiplier 611a multiplies the fundamental current command ICOM by the ratio k3 to the third harmonic supplied from the harmonic current distributor 610 to obtain the third harmonic. A wave current command ICOM3 is generated. By using the third harmonic current command ICOM3, the harmonic current command generator 61B can supply a third harmonic current whose magnitude can be adjusted based on the amplitude of the fundamental current. The same applies to the case of fifth or higher order.

  When the output value of the harmonic current distributor 610 corresponding to a specific order is set to zero or a minute value, the polyphase motor driving device 2 reduces the harmonic components of the order included in the output current. Operate.

  As described above, by setting the output value of the harmonic current distributor 610 to a desired value, the output torque of the polyphase motor 1 is adjusted to a desired value using harmonics exceeding the fundamental frequency. it can.

  An example of a combination of a fundamental wave and harmonics of each order will be described with reference to FIG. FIG. 6 is a diagram for describing a combination of a fundamental wave and harmonics of each order in the embodiment. In the graph shown in FIG. 6, the horizontal axis represents time, and the vertical axis represents voltage amplitude. The period shown on the horizontal axis is one cycle of the fundamental wave. In this graph, in addition to the waveform of the fundamental wave, the third, fifth, seventh, ninth, and eleventh odd-numbered waveforms are drawn as harmonics. A desired synthesized waveform can be generated by superimposing these harmonics whose amplitudes are appropriately determined on the fundamental wave.

  For example, an attempt is made to model a voltage (induced voltage) induced in the winding. In order to easily model the induced voltage, the polyphase motor 1 may be used as a generator. With each winding electrically unloaded, the shaft of the multi-phase motor 1 is driven, and the waveform generated in each winding at that time is defined as an induced voltage. Thereby, the phase and amplitude information of the induced voltage can be obtained. Instead of the modeling method described above, a design decision may be made based on the structure of the polyphase motor 1. It should be noted that a known method can be used for the method of design-wise determination.

  An example of the result of modeling the voltage (induced voltage) induced in the winding is shown in the following equation (12).

  In the above equation (12), n indicates an order, ω indicates an angular velocity, and t indicates time. This equation (12) identifies the induced voltage as a rectangular wave. In the case of the polyphase motor 1 in which the induced voltage can be identified as a rectangular wave, as shown at the origin of the graph of FIG. 6, the phase of the fundamental wave 0 ° coincides with the phase of each harmonic 0 ° at the origin. Furthermore, as can be seen from equation (12), the coefficient indicating the amplitude of the fundamental wave and each harmonic has a positive value, and the phase of each wave is 0 °. Thus, the value of the waveform obtained by combining the waveforms of the respective harmonics at least near 0 ° has a positive value, and the fundamental wave also has a positive value. Therefore, it is possible to combine a signal for instructing the fundamental wave to rotate faster than the fundamental wave. I understand.

  When the induced voltage of the multi-phase motor 1 cannot be identified as a rectangular wave, the equation shown in FIG. 6 cannot be applied. In such a case, the phase advance angle of each waveform is changed to the phase advance angle of the fundamental wave. It is good to determine the value individually, without making it match. The phase angle offset generator 93 generates phase angle offset information for giving the phase of the phase advance angle (phase angle offset) to each harmonic so as to match the above-mentioned induced voltage. If it is difficult to obtain the design, it is possible to rotate the polyphase motor 1 with no load and obtain the phase angle offset information of each harmonic from the induced voltage waveform as described above.

  The harmonic current coefficient for defining the current amplitude for each harmonic order may be determined by the following method. For example, the harmonic current distributor 610 determines the current amplitude for each order of each harmonic from the ratio of each order harmonic no-load magnetic flux to the fundamental wave no-load magnetic flux. The current amplitude of each order is determined so that the ratio of the effective value of the inverter current to the torque (total output torque T / effective value of the current) is maximized, and the harmonics of each harmonic are determined based on the ratio. A current coefficient may be defined. Further, the harmonic current coefficient for each harmonic order with respect to the fundamental current may be determined in consideration of the efficiency and the loss of the polyphase motor 1 and the inverter main circuit 5.

  According to the above embodiment, the inverter main circuit 5 and the control unit 6 are provided. The inverter main circuit 5 adjusts the supply of the AC power to the multi-phase motor 1 by controlling to output the AC power to each winding of the multi-phase motor 1 having a plurality of phases of windings insulated from each other. The control unit 6 controls the inverter main circuit 5. The control unit 6 includes a fundamental voltage command generation unit 60, a harmonic control unit 91, an adder 65, and a PWM control unit 66. The fundamental voltage command generator 60 generates a fundamental voltage command for controlling the output voltage of the inverter main circuit 5 based on the fundamental current command ICOM so that the fundamental current flows through the winding. When n is defined as an arbitrary natural number, the harmonic control unit 91 generates a harmonic voltage command for causing a predetermined 2n + 1-order harmonic current to flow through the winding. The adder 65 adds the output value of the fundamental voltage command and the output value of the harmonic voltage command. The PWM control unit 66 switches the inverter main circuit 5 based on the output value of the adder 65. The harmonic control unit 91 includes a harmonic current command generator 61B and a phase angle offset generator 93. The harmonic current command generator 61B determines a 2n + 1 order harmonic component of the current flowing through the winding based on the fundamental current command ICOM. The phase angle offset generator 93 generates the 2n + 1st harmonic so that a current of the 2n + 1st harmonic component flows through the winding at a phase matched with the phase of the 2n + 1st harmonic component included in the induced voltage of the polyphase motor 1. Determine the current phase of the component. Thereby, the generated torque can be increased by superimposing a desired harmonic current on a desired current phase with reference to the phase of the fundamental wave of the current of the multi-phase motor 1.

  Also, the single-phase inverters 21, 22,... 2N output AC power to each winding of the multi-phase motor 1 having windings of a plurality of phases that are insulated from each other. The inverter main circuit 5 is included in the single-phase inverters 21, 22,... The control unit 6 injects the odd-order harmonic component of the current flowing through the winding by the inverter main circuit 5 at a desired phase with respect to the phase of the actual current flowing through the winding based on the fundamental wave current command ICOM. A command value for superimposing an odd harmonic component of a current flowing through the windings of the polyphase motor 1 with a fundamental wave component of the current flowing through the windings of the polyphase motor 1 at a phase matched with the phase of the polyphase motor 1 Is supplied to the inverter main circuit 5. The command value increases the fluctuation of the output torque of the multi-phase motor 1. Thus, the generated torque can be increased by superimposing a desired harmonic current on a desired current phase with reference to the phase of the fundamental wave of the current of the polyphase motor 1.

  If only n = 1 in the circuit of FIG. 1, the third harmonic current can be reduced and the output current waveform can be controlled. Also, if only n = 2 in the circuit of FIG. 1, the fifth harmonic current can be reduced and the output current waveform can be controlled. Thus, it is also possible to select and configure only a specific order.

(Modification of First Embodiment)
In the first embodiment, the case where the phase of the current command vector is used as the current phase has been described. Instead, in the present modification, the phase obtained by correcting the phase error and fluctuation of the actual current is used. An example will be described.

  In the above embodiment, the reference phase given to the current command calculator 61 is the current advance angle. Further, a DQ phase, which is a reference phase of the orthogonal coordinate converter 67 and the orthogonal coordinate inverse converter 64, is derived based on the voltage induced by the polyphase motor 1. Thus, as shown in FIG. 3, the current command vector is developed on the true D axis and the true Q axis, and so-called feedback current control can be performed on these two axes. However, if the current command vector is developed using the true D-axis and true Q-axis coordinate systems, an error due to a phase error may occur. In such a case, the following method may be selected.

  Referring to FIG. 4, the concept of the control D axis and the control Q axis is introduced, and the phase relationship of the current vector when the control DQ axis is in a phase advanced by the rotation phase correction angle with respect to the true DQ axis. explain. FIG. 4 is a vector diagram for explaining the phase relationship between the current vectors using the concept of the control D axis and the control Q axis of the embodiment. A coordinate system having a control D axis and a control Q axis as axes is defined in the coordinate system shown in FIG. In the coordinate system having the control D axis and the control Q axis as axes, the direction of the control Q axis is the direction of the active power.

  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 61A is a phase angle obtained by subtracting the rotation phase correction angle from the current lead angle. Thus, the control unit 6 derives the D-axis current command and the Q-axis current command by expanding the current command vector on the control D-axis and the control Q-axis at the phase angle. The DQ phase θ, which is the reference phase supplied to the orthogonal coordinate converter 67 and the orthogonal coordinate inverse converter 64, is such that the current phase, which is the feedback amount of feedback current control, is a phase determined by the D-axis current command and the Q-axis current command It is determined to fit. The DQ phase is a value obtained by adding the phase angle determined by the inter-phase difference correction circuit 70 to the given common electrical angle, and adding the rotational phase correction angle to the individually shifted induced voltage phase. . In this way, it is possible to control the true D axis and the true Q axis by the DQ axis that is shifted by the rotation phase correction angle.

  According to the above modification, even when a phase error occurs in the coordinate system between the true D axis and the true Q axis, the effect of the phase error is reduced, thereby achieving the same effect as in the first embodiment. Play.

(Second embodiment)
The second embodiment will be described with reference to FIGS. 7A and 7B.
FIG. 7A is a configuration diagram of the polyphase motor driving device of the embodiment. This embodiment is different from the first embodiment in the point of a method for deriving the D-axis component and the Q-axis component of the odd harmonic current. In the first embodiment, the case has been described in which the D-axis component and the Q-axis component of the odd-order harmonic current are derived from the D-axis current and the Q-axis current of the fundamental wave. In this embodiment, instead of this, an example in which the D-axis component and the Q-axis component of the odd-order harmonic current are derived based on the difference between the real current and the virtual sine wave is shown, which is different from the first embodiment. The explanation will focus on the points.

  FIG. 7A shows a polyphase motor 1, a polyphase motor driving device 2A, a speed control device 3, and a rotation angle detector 4 (PS).

  The multi-phase motor driving device 2A includes single-phase inverters 121, 122,..., 12M. The multi-phase motor driving device 2A drives the multi-phase motor 1 by linking the single-phase inverters 121, 122,..., 12M. , 12M correspond to the above-described single-phase inverters 21, 22,..., 2M. For the connection relationship between the single-phase inverters 121, 122,..., 12M and other configurations, refer to the aforementioned single-phase inverters 21, 22,.

  Next, the single-phase inverters 121, 122,..., 12M will be described. Since the basic configuration of each of the single-phase inverters 121, 122,..., 12M is the same, the single-phase inverter 121 will be described as an example. The single-phase inverter 121 includes an inverter main circuit 5 (inverter unit) and a control unit 6A.

  The controller 6A includes, for example, a fundamental voltage command generator 60A, an adder 65, a PWM circuit 66, a sine calculator 84 (sin), a multiplier 85, and a harmonic controller 92.

  The fundamental wave voltage command generator 60A includes a current command calculator 61A, subtractors 62A and 62B, a D-axis current controller 63A, a Q-axis current controller 63B, a rectangular coordinate inverse converter 64, and an adder 69. , 71, 72A, a rectangular coordinate converter 67, an inter-phase difference correcting circuit 70, a cosine calculator 73, an amplitude calculator 74, and a multiplier 75.

  The adder 72A corresponds to the adder 72 described above. The output of the adder 72A is connected to the input of the cosine calculator 73 and the input of the sine calculator 84. The adder 72A adds the current advance angle supplied from the current phase operation circuit 35 to the DQ phase θ supplied from the adder 71, and outputs the result to the input of the cosine operation unit 73 and the sine operation unit 84. Input and supply respectively. The sine calculator 84 derives a sine (sin) of the DQ phase θ to which the current lead angle has been added. The output of the sine calculator 84 is connected to the first input of the multiplier 85. A second input of the multiplier 85 is connected to an output of the amplitude calculator 74. The multiplier 85 generates a virtual sine wave by multiplying the current command amplitude derived by the amplitude calculator 74 by the sine of the DQ phase θ to which the current lead angle has been added. The output of the multiplier 85 is connected to the harmonic control unit 92, and the multiplier 85 supplies the virtual sine wave to the harmonic control unit 92.

  The input of the harmonic controller 92 is connected to the output of the current detector 51, the output of the multiplier 85, the output of the adder 71, and the output of the current phase operation circuit 35, respectively. It is connected to the second input of the adder 65. The real current detected by the current detector 51, the virtual sine wave output from the multiplier 85 having the same phase as the real current, and the DQ phase θ output from the adder 71 are supplied to the harmonic control unit 92. You. The harmonic controller 92 generates an odd harmonic voltage command corresponding to the fundamental current command ICOM and the detected actual current, and generates a composite harmonic correction command based on the command.

  An example of the harmonic controller 92 according to the embodiment will be described with reference to FIG. 7B. FIG. 7B is a configuration diagram of the harmonic control unit 92 of the embodiment.

  The harmonic control unit 92 includes, for example, a harmonic current command generator 61B, a subtractor 86, a phase angle offset generator 93, a harmonic voltage generator 95A, and an adder 94.

  The first input of the subtractor 86 is supplied with actual current feedback from the output of the current detector 51, and the second input of the subtractor 86 is supplied with a virtual sine wave from the output of the multiplier 85. The output of the subtractor 86 is connected to the input of the harmonic voltage generator 95A. The subtractor 86 derives the difference between the real current feedback from the current detector 51 and the virtual sine wave from the multiplier 85, and extracts odd harmonic components except at least the fundamental component in the real current. The subtractor 86 supplies the above difference, that is, each odd-order harmonic component to the harmonic voltage generator 95A.

  The harmonic voltage generator 95A has a plurality of inputs and N outputs. The plurality of inputs of the harmonic voltage generator 95 are supplied with the DQ phase θ, the output signal of the subtractor 86, the harmonic current command of each order, and the phase angle offset of each order.

  The harmonic voltage generator 95A includes harmonic generators 951A, 952A,..., 95NA. For example, the harmonic generators 951A, 952A,..., 95NA are assigned so as to generate third, fifth,. N is the number of harmonics having different orders.

  The inputs of the harmonic generators 951A, 952A,..., 95NA are to the output of the subtractor 86, the output of the harmonic current command generator 61B, the output of the phase angle offset generator 93, and the adder 71. Each is connected.

  The difference output from the subtractor 86 and the DQ phase θ output from the adder 71 are independently supplied to the inputs of the harmonic generators 951A, 952A,..., 95NA. The odd-order harmonic command output from the harmonic current command generator 61B and the phase angle offset output from the phase angle offset generator 93 are input to the harmonic generators 951, 952,. Each is given independently.

  , 95NA are an odd-order harmonic component supplied from the subtractor 86, an odd-order harmonic command supplied from the harmonic current command generator 61B, and a phase angle offset. Based on the phase angle offset supplied from the generator 93 and the DQ phase θ, third-order, fifth-order,..., 2n + 1-order harmonics are respectively generated. Each of the above harmonics may be obtained by adding a phase difference corresponding to a phase angle offset to the DQ phase θ. The magnitude of the phase difference can be predetermined in design. Alternatively, it can be obtained from the induced voltage when the multi-phase motor 1 is rotated with no load as described above.

  The outputs of the harmonic generators 951A, 952A,..., 95NA are connected to the respective inputs of the adder 94, respectively. The adder 94 adds the third, fifth,..., 2n + 1-order harmonic voltage command values supplied from the harmonic generators 951A, 952A,. Is supplied to the adder 65 as a combined harmonic correction command.

  The harmonic generator 951A includes a rectangular coordinate converter 87, low-pass filters 88A and 88B, subtractors 78A and 78B, harmonic current controllers 79A and 79B, a rectangular coordinate inverse converter 80, And a DQ phase calculator 831.

  The tertiary DQ phase calculator 831 has its input connected to the output of the adder 71 and its output connected to the first input of the adder 89A. The third-order DQ phase calculator 831 multiplies the DQ phase θ by 2n + 1 and outputs the result. In the case of the third-order DQ phase calculator 831, the value of n is 1.

  A first input of the adder 89A is connected to an output of the third-order DQ phase calculator 831. An output of the adder 89A is connected to a reference phase input of the orthogonal coordinate converter 87 and a reference phase input of the orthogonal coordinate inverter 80. It is connected to the. One of a plurality of outputs of the phase angle offset generator 93 is connected to a second input of the adder 89A.

  The adder 89A adds the value of the third harmonic offset angle supplied from the phase angle offset generator 93 to the value of 2nθ + θ obtained by multiplying the DQ phase θ supplied from the third DQ phase calculator 831 by 2n + 1 times. Then, the sum is output as a signal of the reference phase of the orthogonal coordinate converter 87 and the orthogonal coordinate inverter 80.

  The orthogonal coordinate converter 87 has A-axis input and B-axis input as input terminals, D-axis output and Q-axis output as output terminals, and a reference phase input. The output of the subtractor 86 is connected to the A-axis input of the orthogonal coordinate converter 87, and the deviation output by the subtractor 86 is supplied. 0 is supplied to the B-axis input. To the reference phase terminal of the orthogonal coordinate converter 87, a signal in which the DQ phase θ is tripled is supplied from the third-order DQ phase calculator 831 via the adder 89A. The orthogonal coordinate converter 87 triples the DQ phase θ supplied to the reference phase input based on the output signal of the subtractor 86 supplied to the A-axis input and the value of 0 supplied to the B-axis input. DQ conversion is performed based on the set signal, and the result is output from the D-axis output and the Q-axis output.

  The output of the orthogonal coordinate converter 87 is a D-axis component and a Q-axis component obtained by projecting the 2n + 1-order harmonic current included in the actual current onto orthogonal rotation coordinates rotating at a frequency of 2n + 1 times. In the case of the harmonic generator 951A, n is 1. Two outputs of the orthogonal coordinate converter 87 are respectively connected to inputs of the low-pass filters 88A and 88B. The component based on the third harmonic is converted by the orthogonal coordinate converter 87 into a DC component in the converted signal. It should be noted that the third harmonic offset angle θoffset3 with respect to the DQ phase θ may be set for the signal whose DQ phase θ is tripled.

  The low-pass filters 88A and 88B have their inputs connected to the two outputs of the orthogonal coordinate converter 87, respectively, and their outputs connected to the first inputs of the subtracters 78A and 78B, respectively. The low-pass filters 88A and 88B transmit low-frequency components included in the D-axis current and the Q-axis current output from the orthogonal coordinate converter 87.

  A first input of the subtractor 78A is connected to an output of the low-pass filter 88A, and an output of the subtractor 78A is connected to an input of the harmonic current controller 79A. A first input of the subtractor 78B is connected to an output of the low-pass filter 88B, and an output of the subtractor 78B is connected to an input of the harmonic current controller 79B. The second input of the subtractor 78A is supplied with zero or a minute value, and the second input of the subtractor 78B is connected to one of a plurality of outputs of the harmonic current command generator 61B.

  The subtractor 78B adds one of a plurality of command values output by the harmonic current command generator 61B to the output value of the low-pass filter 88A, and supplies the result to the input of the harmonic current controller 79B. . The third harmonic current command ICOM3 is an example of a plurality of command values.

  The harmonic current controller 79A performs a proportional-integral control or the like on the output value of the subtractor 78A, and issues a D-axis voltage correction command so that the first input signal of the subtractor 78A follows the second input signal of the calculator 78A. Generate The harmonic current controller 79B performs a proportional-integral control or the like on the output value of the subtractor 78B to correct the Q-axis voltage so that the output value of the low-pass filter 88B follows the value of the third harmonic current command ICOM3. Generate a command.

  The output of the harmonic current controller 79A is connected to the D-axis input, which is the input terminal of the orthogonal coordinate inverter 80, and a D-axis voltage correction command is supplied from the harmonic current controller 79A. The output of the harmonic current controller 79B is connected to the Q-axis input, which is the input terminal of the orthogonal coordinate inverse converter 80, and a Q-axis voltage correction command is supplied from the harmonic current controller 79B. The orthogonal coordinate inverse converter 80 performs the inverse DQ conversion on the basis of the signal obtained by triple the DQ phase θ supplied from the tertiary DQ phase calculator 831 to the reference phase input via the adder 89A, and performs orthogonal conversion. The output of the coordinate inverse transformer 80 is returned to the fixed coordinate system. The information output from the orthogonal coordinate inverter 80 includes the correction amount of the third harmonic current. An A-axis output of the orthogonal coordinate inverse transformer 80 is connected to one of a plurality of inputs of the adder 94. The orthogonal coordinate inverse converter 80 supplies the output value to the adder 94. It should be noted that the third harmonic offset angle θoffset3 with respect to the DQ phase θ may be set for the signal whose DQ phase θ is tripled.

  The harmonic generator 952A includes a fifth-order DQ phase calculator 832 instead of the third-order DQ phase calculator 831 of the harmonic generator 951A. The harmonic generator 95NA includes a 2n + 1st-order DQ phase calculator 83N instead of the third-order DQ phase calculator 831 of the harmonic generator 95NA.

  .., 95NA, 0 is given to the input B of the orthogonal coordinate converter 87, and the 2n + 1-order DQ phase calculator 83N having the DQ phase θ as an input. DQ conversion is performed to the orthogonal coordinate system based on the output signal of

  For example, the 2n + 1-order DQ phase calculator 83N outputs 2θn + θ obtained by multiplying the DQ phase θ by 2n + 1 to the orthogonal coordinate inverse converter 80 via the adder 89A. The low-pass filter 88A obtains a DC component of the obtained D-axis current value. The low-pass filter 88B obtains the DC component of the Q-axis current value. As a result, the outputs of the low-pass filters 88A and 88B change the 2n + 1-order harmonic current included in the actual current by a quadrature rotation that rotates at a frequency 2n + 1 times the DQ phase θ, as in the first embodiment. The D-axis component and the Q-axis component when projected onto coordinates. For the subsequent control, a method similar to that of the first embodiment can be applied, and a detailed description thereof will be omitted.

  The configuration for creating the virtual sine wave is not limited to the configuration shown in FIG. 7A. For example, the phase of the virtual cosine wave output from the multiplier 75 may be shifted by calculation.

  The circuit of FIG. 7B can generate a third harmonic current if n = 1, or can generate a fifth harmonic current if n = 2.

  According to the above embodiment, the same effects as in the first embodiment can be obtained. The sine calculator 84 generates a virtual sine wave equal in amplitude to the fundamental wave current command ICOM or the fundamental wave of the actual current, and in phase with the fundamental wave current command ICOM or the fundamental wave of the actual current. The harmonic control unit 92 gives the difference between the real current and the virtual sine wave to the orthogonal coordinate converter 87, and outputs the outputs of the two axes via low-pass filters 88A and 88B. The output for each component of the bandpass filters 88A and 88B is set as the output value detected by the harmonic control unit 92. Thereby, the polyphase motor driving device 2A can detect the odd harmonic contained in the actual current by the harmonic control unit 92, and can increase the amplitude of the detected odd harmonic. .

  According to at least one embodiment described above, the polyphase motor driving device includes an inverter unit and a control unit. The inverter adjusts the supply of the AC power to the multi-phase motor by controlling the output of the AC power to each winding of the multi-phase motor having the multi-phase windings insulated from each other. The control unit controls the inverter unit. The control unit includes a fundamental voltage command generation unit, a harmonic control unit, an adder, and a switching control unit. The fundamental wave voltage command generation unit generates a fundamental wave voltage command for controlling an output voltage of the inverter unit such that a fundamental wave current flows through the winding based on the fundamental wave current command. When n is defined as an arbitrary natural number, the harmonic control unit generates a harmonic voltage command for flowing a predetermined 2n + 1st harmonic current through the winding. The adder adds the output value of the fundamental voltage command and the output value of the harmonic voltage command. The switching control unit switches the inverter unit according to the output value of the adder. The harmonic control unit includes a harmonic current generator and a phase angle offset generator. The harmonic current generator determines a 2n + 1 order harmonic component of the current flowing through the winding based on the fundamental current command. The phase angle offset generator generates a 2n + 1 order harmonic component so that a current of the 2n + 1 order harmonic component flows through the winding at a phase matched with the phase of the 2n + 1 order harmonic component included in the induced voltage of the polyphase motor. By determining the current phase, a predetermined harmonic current is superimposed at a desired phase, and the output torque of the polyphase motor can be further increased.

  The control device described above may be realized, at least in part, by a software function unit that functions when a processor such as a CPU executes a program, or may be entirely realized by a hardware function unit such as an LSI. .

  Although several embodiments of the present invention have been described, these embodiments are provided by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in other various forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and equivalents thereof.

  For example, in FIG. 1A and FIG. 7A, the main voltage command output by the orthogonal coordinate inverse converter 64 uses the A-axis component shown in Expression (3), and in response to this, the orthogonal coordinate converter 67 Although the real 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 Expression (4) is used for the main voltage command, and the B-axis component of the orthogonal coordinate converter 67 is used. It is also possible to input a real current and a virtual cosine wave into the A-axis component. The point is that 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. Note that, although the term “virtual cosine wave” is described, the difference between cosine wave and sine wave is simply the difference in phase relationship. If a virtual wave can be created with a phase matching the above phase relationship, the cosine (cos) Which one of (operation) / sine (sin operation) is used is arbitrary.

  The “virtual cosine wave” and “virtual sine wave” indicate that a waveform is generated based on phase information, not the component itself included in the detected signal. The “virtual cosine wave” and “virtual sine wave” can be replaced with “cosine wave” and “sine wave” generated by the same method as described above.

  Further, although the current lead angle and the rotation phase correction angle are both described as positive values, either one may be negative or both may be negative.

  In the second embodiment, odd-numbered DQ conversion is performed using a virtual sine wave having the same phase and the same amplitude as the actual current to derive the DQ component of the odd-order harmonic. It is also possible to derive odd-order harmonics. In the first embodiment, it is also possible to extract odd harmonics from the output value of the orthogonal coordinate converter 67 using a high-pass filter or a band-pass filter. However, in either case, since the amount of alternating current is filtered, an error due to a phase shift occurs, and the detection accuracy may be reduced. In addition, since the phase delay due to the filter increases as the fundamental wave frequency increases, it is often difficult to accurately extract the phase of the harmonic current. However, in the present embodiment, since the harmonic is detected by the coordinate conversion, the phase of the harmonic current can be detected with high accuracy, so that a predetermined harmonic component can be injected at a predetermined phase.

  Further, in the above embodiment, since filtering for separating and extracting the DC amount and the AC current amount is performed, an error hardly occurs even when the frequency of the fundamental wave (corresponding to the operation speed) changes. However, in the region where the operating speed is low, the frequency of the odd-order harmonic is also low. For this reason, the cutoff frequency of the low-pass filter may be reduced according to the decrease in the operating speed.

  Further, although the current command calculator 61 in FIG. 1 is provided inside the control unit 6, the current command calculator 61 is provided inside the commonly provided speed control device 3, and the D-axis current command and the Q-axis current command are provided by a single-phase inverter. 21 may be provided.

DESCRIPTION OF SYMBOLS 1 ... Polyphase motor, 21, 22, 2M ... Single phase inverter, 3 ... Speed control device, 4 ... Rotation angle detector, 5 ... Inverter main circuit (inverter part), 6 ... Control part, 31 ... Speed detection circuit, 32: subtractor, 33: speed controller, 34: electric angle calculation circuit, 35: current phase calculation circuit, 51: current detector, 60, 60A: fundamental wave voltage command generator, 61A: current command calculator, 61B ... Harmonic current command generators, 62A, 62B ... Subtractors (comparators), 63A ... D-axis current controllers, 63B ... Q-axis current controllers, 64 ... Cartesian coordinate inverse converters, 65 ... Adders, 66 ... PWM circuit (switching control unit), 67: rectangular coordinate converter, 68A, 68B: low-pass filter (first low-pass filter), 69: adder, 70: phase difference correcting circuit, 71: adder , 72, 72A ... adder, 73 Cosine calculator, 74: amplitude calculator, 75: multiplier, 76A, 76B: subtractor, 77: rectangular coordinate converter, 78A, 78B: subtractor, 79A, 79B: harmonic current controller, 80: rectangular coordinate Inverter, 81N 2nd-order DQ phase calculator, 811 second-order DQ phase calculator, 812 4th-order DQ phase calculator, 82N, 83N 2nd + 1-order DQ phase calculator, 821, 831 3rd-order DQ phase Arithmetic units, 822, 832: 5th-order DQ phase arithmetic unit, 831: 3rd-order DQ phase arithmetic unit, 84: sine arithmetic unit, 85: multiplier, 86: subtractor, 87: orthogonal coordinate converter, 88A, 88B ... Low-pass filters (second low-pass filters), 89A, 89B ... adders, 91, 92 ... harmonic control units, 93 ... phase angle offset generators, 95, 95A ... harmonic voltage generators, 951, 952, 95N, 51A, 952A, 95NA ... harmonic generator

Claims (9)

An inverter unit connected to each winding of a polyphase motor having a plurality of windings insulated from each other to supply AC power to the polyphase motor;
A control unit that controls the inverter unit;
With
The control unit includes:
Based on a fundamental wave current command, a fundamental wave voltage command generation unit that generates a fundamental wave voltage command for controlling an output voltage of the inverter unit so that a fundamental wave current flows through the winding,
when n is defined as an arbitrary natural number, a harmonic control unit that generates a 2n + 1-order harmonic voltage command for flowing a predetermined 2n + 1-order harmonic current through the winding;
An adder that adds the output value of the fundamental voltage command and the output value of the harmonic voltage command,
A switching control unit that switches the inverter unit according to an output value of the adder,
The harmonic controller,
A harmonic current command generator that commands a 2n + 1 order harmonic component of a current flowing through the winding;
A phase angle offset generator for instructing a phase for determining a phase of a 2n + 1 order harmonic component of a current flowing through the winding with respect to an induced voltage of a fundamental wave of the polyphase motor,
A harmonic current command value which is an output of the harmonic current command generator, a phase angle offset command which is an output of the phase angle offset generator, and a 2n + 1 order harmonic component of a current flowing through the winding is the harmonic. A multi-phase motor drive device that generates the 2n + 1st harmonic voltage command so as to follow a current command value and the phase angle offset command. The harmonic current command generator,
Determining the harmonic current command based on the fundamental current command,
The polyphase motor driving device according to claim 1. The harmonic current command generator,
The harmonic current command is determined based on a fundamental current flowing through the base winding,
The polyphase motor driving device according to claim 1. The phase angle offset command of the 2n + 1 order harmonic component with respect to the phase of the fundamental wave is determined based on an induced voltage waveform obtained from design data of the multi-phase motor,
The polyphase motor driving device according to claim 1. The phase angle offset command of the 2n + 1 order harmonic component with respect to the phase of the fundamental wave is determined based on an induced voltage waveform when the polyphase motor is rotated with no load.
The polyphase motor driving device according to claim 1. The fundamental voltage command generator,
In a coordinate system having a control D axis and a control Q axis orthogonal to each other, the direction of the control Q axis is determined as the direction of active power, and the fundamental wave current command is transmitted to two axes of the control D axis and the control Q axis. Current command calculation means for developing the current command;
Based on the amplitude of the fundamental wave of the actual current flowing through the winding or the amplitude of the fundamental current command, the amplitude is determined, and a virtual cosine wave having a phase orthogonal to the vector phase of the fundamental current command is generated. Virtual cosine wave generation means;
First orthogonal rotation coordinate conversion means for performing orthogonal rotation coordinate conversion using the real current and the virtual cosine wave,
With
The main voltage command is performed by performing current control such that the current components of the two axes obtained by the first orthogonal rotation coordinate conversion means follow the current commands of the two axes obtained by the current command calculation means. And output
The harmonic voltage command generator further includes:
The 2n + 1-order harmonic component included in the actual current is detected as a component of two axes of a higher-order D axis and a higher-order Q axis projected on orthogonal rotation coordinates rotating at a frequency of 2n + 1 times the frequency of the fundamental wave. Second harmonic current detection means,
Higher-order Q-axis current control means for outputting a higher-order Q-axis voltage command so that the detected value of the higher-order Q-axis component follows the harmonic current command value;
High-order D-axis current control means for outputting a high-order D-axis voltage command so as to follow the detected value of the high-order D-axis component to zero or a minute value;
A first higher-order signal which receives the signals of the higher-order Q-axis control command and the higher-order D-axis current control command, reversely converts the orthogonal rotation coordinate system into a stationary coordinate system, and generates the 2n + 1 order harmonic voltage command; Orthogonal coordinate inverse transformation means,
With
The first orthogonal rotation coordinate conversion means and the first higher-order orthogonal coordinate inverse conversion means use, as a reference phase, a phase angle individually shifted in accordance with a phase difference between respective windings of the polyphase motor.
The polyphase motor driving device according to claim 1. Each of the two-axis current components obtained by the first orthogonal rotation coordinate conversion means is compared with the two-axis current commands obtained by the current command calculation means via a first low-pass filter. A comparison unit
The 2n + 1 order harmonic detecting means includes:
The difference between the input and output of the first low-pass filter provided for each of the two-axis current components is taken for each of the two-axis current components, and the respective differences are given to a second orthogonal rotation coordinate conversion means. ,
The second orthogonal rotation coordinate conversion means includes:
The orthogonal rotation coordinate conversion is performed at a frequency 2n times the frequency of the same reference phase as that of the first orthogonal rotation coordinate conversion means,
An output for each of the components of the two axes of the second orthogonal rotation coordinate conversion unit is set as an output value detected by the 2n + 1-order harmonic detection unit.
The multi-phase motor driving device according to claim 6. Virtual sine wave generating means for generating a virtual sine wave equal in amplitude to the fundamental wave current command or the fundamental wave of the real current, and in phase with the fundamental wave current command or the fundamental wave of the real current,
The 2n + 1 order harmonic detecting means includes:
The difference between the real current and the virtual sine wave is given to a third orthogonal rotation coordinate conversion means, and the output of each of the two axes is output via a second low-pass filter. The output of each component is defined as an output value detected by the 2n + 1 order harmonic detection means,
The multi-phase motor driving device according to claim 6. The control unit includes:
The 2n + 1st-order harmonic detection means is provided in a plurality, and the plurality of 2n + 1st-order harmonic detection means have different values of n from each other.
The harmonic current control means is provided in a plurality corresponding to each of the plurality of 2n + 1 order harmonic detection means,
Each of the plurality of harmonic current control means outputs a 2n + 1 order harmonic auxiliary voltage command corresponding to the value of n of the 2n + 1 order harmonic detection means,
A value obtained by adding and summing the plurality of 2n + 1 order harmonic auxiliary voltage commands was defined as the harmonic current command value.
The polyphase motor driving device according to any one of claims 6 to 8.

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