Control device

Abstract

To disclose a technique for suppressing occurrence of noise and vibration due to an operation of a motor.SOLUTION: A control device comprises: a dq current conversion unit which converts current flowing to stator windings of each phase into d-axis current and q-axis current; a dq command voltage calculation unit which calculates d-axis command voltage and q-axis command voltage, respectively; a three-phase conversion unit which receives the d-axis command voltage and the q-axis command voltage to convert them into three-phase voltage; and a supply unit which supplies power to a three-phase AC motor on the basis of the three-phase voltage. The d-axis current command value and the q-axis current command value include current harmonic components, respectively. The control device comprises: a dq inductor voltage calculation unit which calculates d-axis inductor voltage on the basis of a time change amount of the d-axis current command value and d-axis inductance, and calculates q-axis inductor voltage on the basis of a time change amount of the q-axis current command value and q-axis inductance; and an addition unit which adds the d-axis inductor voltage and the q-axis inductor voltage to the d-axis command voltage and the q-axis command voltage, respectively.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The technology disclosed in this specification relates to a control device for controlling a three-phase AC motor. [Background technology]

[0002] Patent Document 1 discloses a three-phase AC motor control device. This control device removes harmonic components from the current flowing through the motor. The control device also compensates for the effect of the speed electromotive force by a feedforward compensator. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2004-312864 A Summary of the Invention [Problem to be solved by the invention]

[0004] Due to the influence of harmonics in the current flowing through the motor, harmonic components are also superimposed on the self-inductance and mutual inductance of the windings of each phase of the motor. The above technology does not take into account such harmonic components of the self-inductance and mutual inductance. When such harmonic components of the self-inductance and mutual inductance exist, the ability to follow the command value decreases in the control of the current containing the harmonic components. When the ability to follow the command value decreases, noise and vibrations occur when the motor operates.

[0005] This specification discloses a technique for suppressing the generation of noise and vibration due to the operation of a motor. [Means for solving the problem]

[0006] This specification discloses a control device for a three-phase AC motor. The control device includes a current detection unit that detects a current flowing through a stator winding of each phase of the three-phase AC motor, a rotation angle detection unit that detects a rotation angle of a rotor of the three-phase AC motor, a dq current conversion unit that converts the detected current flowing through the stator winding of each phase into a d-axis current and a q-axis current in a dq rotating coordinate system that rotates in synchronization with the rotation of the rotor based on the detected rotation angle of the rotor, a dq command voltage calculation unit that calculates a d-axis command voltage and a q-axis command voltage based on a d-axis deviation that is a deviation between a d-axis current command value and the d-axis current and a q-axis deviation that is a deviation between a q-axis current command value and the q-axis current, a three-phase conversion unit that receives the d-axis command voltage and the q-axis command voltage and converts them into three-phase voltages, and a supply unit that supplies power to the three-phase AC motor based on the three-phase voltages. the d-axis inductor voltage calculation unit calculates a d-axis inductor voltage based on a time change amount of the d-axis current command value that changes according to the rotation angle of the rotor and a d-axis inductance of the three-phase AC motor, and calculates a q-axis inductor voltage based on a time change amount of the q-axis current command value that changes according to the rotation angle of the rotor and a q-axis inductance of the three-phase AC motor; and an adder that adds the d-axis inductor voltage and the q-axis inductor voltage to the d-axis command voltage and the q-axis command voltage, respectively. When a three-phase to two-phase transformation matrix is ​​X, a rotational coordinate transformation matrix is ​​Y, and an inductance matrix is ​​L, the d-axis inductance is expressed by the following equation: T X T The q-axis inductance is calculated as the (1, 1) component of the matrix expressed by the following equation, and the q-axis inductance is calculated as the (2, 2) component of the matrix. The inductance matrix L is calculated by dividing the self-inductance L of each phase of the stator winding by the U , L V , L W and mutual inductance M UV , M VW , M WU The self-inductance L U , LV , L W and the mutual inductance M UV , M VW , M WU Each of the three-phase to two-phase transformation matrix X, the rotation coordinate transformation matrix Y, and the inductance matrix L is expressed by the following equations:

number

[0007] According to the above configuration, the control device calculates the d-axis inductor voltage based on the d-axis inductance, and calculates the q-axis inductor voltage based on the q-axis inductance. The d-axis inductance and the q-axis inductance include information on the harmonic components of the self-inductance and mutual inductance of the stator windings of each phase of the three-phase AC motor. That is, the d-axis inductor voltage and the q-axis inductor voltage also include information on the harmonic components of the self-inductance and mutual inductance. Then, the control device calculates the d-axis command voltage by adding the d-axis inductor voltage to the d-axis control voltage, and calculates the q-axis command voltage by adding the q-axis inductor voltage to the q-axis control voltage. As a result, the ability to follow the command value is improved. Therefore, it is possible to suppress the generation of noise and vibration due to the operation of the motor.

[0008] In one embodiment of the present technology, the control device may further include a current command value generating unit that determines the d-axis current command value and the q-axis current command value based on a rotation speed of the three-phase AC motor. In this case, the current command value generating unit may have a harmonic current map that describes the orders of the current harmonic components to be imparted to the d-axis current command value and the q-axis current command value, and the amplitudes and phases of each of the orders of the current harmonic components (i.e., the current harmonic components of each order), using the rotation speed of the three-phase AC motor as a parameter.

[0009] Noise and vibration caused by the operation of the motor are transmitted to a specific location (e.g., the interior of a vehicle) of a device (e.g., an electric vehicle) in which the motor is mounted, and noise or vibration occurs at the specific location. In particular, when an electromagnetic forcing force with a frequency component close to the resonance frequency of the transmission system occurs, the generation of noise or vibration at the specific location becomes noticeable. The resonance frequency of the transmission system is a substantially constant value, but the frequency of each order of the electromagnetic forcing force changes according to the rotation speed of the motor. In consideration of this, the above configuration has a harmonic current map that describes the order of the harmonic to be applied to the current command value and the respective amplitudes and phases, with the rotation speed as a parameter. This allows the control device to specify the order, current amplitude, and phase of the harmonic included in the resonance frequency band of the transmission system using the harmonic current map. For this reason, the control device can output d-axis current command value and q-axis current command value that cancel the electromagnetic forcing force of a frequency that is a significant cause of noise or vibration at the specific location, among the frequencies of each order of the harmonic that change according to the rotation speed of the motor. This makes it possible to reduce the influence of noise and vibration caused by the operation of the motor.

[0010] In addition, when the harmonic components to be applied are limited, the loss caused by the flow of harmonic currents can be reduced compared to the case where all harmonic components are applied to the d-axis current command value and the q-axis current command value. [Brief description of the drawings]

[0011] [Figure 1] FIG. 2 shows a block diagram of an electric vehicle equipped with a control device. [Diagram 2] A block diagram of a control device is shown. [Diagram 3] 4 shows a block diagram of an inductor voltage estimator. [Figure 4] 13 shows a flowchart of a process executed by an inductor voltage estimator. [Diagram 5] 4 shows an example of waveforms of self-inductance and mutual inductance. [Figure 6]FIG. 6(a) shows an example of the amplitude of the harmonics of self-inductance and mutual inductance, FIG. 6(b) shows an example of the phase of the harmonics of self-inductance, and FIG. 6(c) shows an example of the phase of the harmonics of mutual inductance. [Figure 7] 4 shows an example of waveforms of d-axis inductance and q-axis inductance. [Figure 8] FIG. 8(a) shows an example of the amplitudes of the harmonics of the d-axis inductance and the q-axis inductance, and FIG. 8(b) shows an example of the phases of the harmonics of the d-axis inductance and the q-axis inductance. [Figure 9] FIG. 9(a) shows an example of a waveform of a q-axis current command value (dashed line), a waveform of the q-axis current when a q-axis inductor voltage is applied (solid line), and a waveform of the q-axis current when no q-axis inductor voltage is applied (dotted line). FIG. 9(b) shows an example of a waveform of a d-axis current command value (dashed line), a waveform of the d-axis current when a d-axis inductor voltage is applied (solid line), and a waveform of the d-axis current when no d-axis inductor voltage is applied (dotted line). [Figure 10] A block diagram of a dq-axis current command value generating unit is shown. [Figure 11] 4 shows a flowchart of a process executed by a dq-axis current command value generating unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] This specification discloses a control device 30 for a three-phase AC motor 14. As shown in Fig. 1, the control device 30 of this embodiment is mounted on an electric vehicle 2 including a battery 10 and a three-phase AC motor 14 for driving. The electric vehicle 2 is not particularly limited, but may be, for example, an electric vehicle, a hybrid vehicle, a plug-in hybrid vehicle, or a fuel cell vehicle.

[0013] The electric vehicle 2 includes a battery 10, a capacitor 12, a three-phase AC motor 14, a current sensor 16, a rotation angle sensor 18, an inverter 20, and a control device 30. The battery 10 outputs DC power. The battery 10 is, for example, a lithium-ion battery. The output power of the battery 10 is supplied to a converter (not shown), which boosts the output power of the battery 10. The power (DC power) boosted by the converter is supplied to the inverter 20. The inverter 20 converts the supplied DC power into three-phase AC power and supplies it to the three-phase AC motor 14.

[0014] The three-phase AC motor 14 of this embodiment is a so-called three-phase Y-connection (star-connection) motor, and includes a U-phase coil 14U, a V-phase coil 14V, and a W-phase coil 14W. The inverter 20 includes six switching elements 22a to 22f. The two switching elements 22a and 22b control the power supplied to the U-phase coil 14U of the three-phase AC motor 14. The two switching elements 22c and 22d control the power supplied to the V-phase coil 14V of the three-phase AC motor 14. The two switching elements 22e and 22f control the power supplied to the W-phase coil 14W of the three-phase AC motor 14.

[0015] The current sensor 16 detects the current supplied to the three-phase AC motor 14. As shown in Fig. 1, the current sensor 16 of this embodiment detects a U-phase current supplied to the U-phase coil 14U and a V-phase current supplied to the V-phase coil 14V. The sum of the instantaneous values ​​of the U-phase current, the V-phase current, and the W-phase current supplied to the W-phase coil 14W is zero, so if the U-phase current and the V-phase current can be detected, the W-phase current is also detected. The rotation angle sensor 18 detects the rotation angle of a rotor (not shown) of the three-phase AC motor 14.

[0016] The control device 30 controls the three-phase AC motor 14 by controlling each of the switching elements 22a-22f of the inverter 20. The control device 30 is configured to be able to communicate with the current sensor 16 and the rotation angle sensor 18, and acquires the detection values ​​of each. The control device 30 generates a drive signal (e.g., a PWM signal) based on the detection values ​​of the current sensor 16 and the rotation angle sensor 18. Each of the switching elements 22a-22f of the inverter 20 is controlled based on the above drive signal.

[0017] 2, the control device 30 includes a UVW / dq conversion unit 31, a dq-axis voltage command calculation unit 32, an inductor voltage estimation unit 33, a dq / UVW conversion unit 34, a PWM signal generation unit 35, a dq-axis non-interacting term 36, and four adders A1 to A4. The control device 30 further includes a dq-axis current command value generation unit 40. The dq-axis current command value generation unit 40 generates a d-axis DC current command value I d_DC * and q-axis DC current command value I q_DC * and the d-axis current command value I d * and q-axis current command value I q * The d-axis DC current command value I d_DC * and q-axis DC current command value I q_DC * is determined in a control device (not shown) higher than the control device 30, based on, for example, the accelerator opening degree set by the user.

[0018] The UVW / dq conversion unit 31 converts the U-phase current I U and V-phase current I V , and the rotor angle θ detected by the rotation angle sensor 18, and a three-phase current I U ,I V ,I W , d-axis current I d and q-axis current I q The converted d-axis current I d is supplied to an adder A1. The converted q-axis current I qis supplied to an adder A2. The specific method of the above conversion is well known to those skilled in the art, so a detailed description will be omitted.

[0019] The dq-axis voltage command calculation unit 32 calculates a d-axis command voltage and a q-axis command voltage. Specifically, the dq-axis voltage command calculation unit 32 first calculates the d-axis current command value I d * and the d-axis current I output by the UVW / dq conversion unit 31. d and the d-axis deviation (I d * -I d ) from the adder A2. The dq-axis voltage command calculation unit 32 then calculates and outputs a d-axis command voltage that makes the d-axis deviation zero (i.e., brings the actual current closer to the command value). The calculated d-axis command voltage is supplied to the adder A3. Similarly, the dq-axis voltage command calculation unit 32 receives the q-axis deviation (I q * -I q ), calculates and outputs a q-axis command voltage. The calculated q-axis command voltage is supplied to an adder A4. That is, the dq-axis voltage command calculation unit 32 calculates the d-axis command voltage and the q-axis command voltage by feedback control. The dq-axis voltage command calculation unit 32 is realized by, for example, a PI controller. d * and q-axis current command value I q * contains harmonic components that are integer multiples of the fundamental frequency of the current flowing through the coils 14U, 14V, 14W of each phase of the three-phase AC motor 14.

[0020] As mentioned above, the d-axis current command value I d * and q-axis current command value I q * contains harmonic components. d-axis current command value I d * and q-axis current command value I q *contains harmonic components, a delay in the command value occurs (i.e., tracking ability to the command value decreases) with only the feedback control executed by the dq-axis voltage command calculation unit 32 described above. If a delay in the command value occurs, noise and vibration occur due to the operation of the three-phase AC motor 14. Therefore, in order to compensate for this delay, the control device 30 of this embodiment includes an inductor voltage estimation unit 33. The inductor voltage estimation unit 33 estimates the d-axis current command value I d * and the q-axis current command value I q * and the rotor angle θ, and calculates and outputs the d-axis inductor voltage and the q-axis inductor voltage to be added as feedforward terms to the d-axis command voltage and the q-axis command voltage, respectively. The calculated d-axis inductor voltage is supplied to an adder A3. The calculated q-axis inductor voltage is supplied to an adder A4.

[0021] In particular, the d-axis current command value I d * and q-axis current command value I q * Due to the harmonic components contained in the self-inductance and mutual inductance of the coils 14U, 14V, and 14W of each phase of the three-phase AC motor 14, the self-inductance and mutual inductance also contain harmonic components. In this embodiment, the d-axis inductor voltage and the q-axis inductor voltage are calculated as values ​​taking into account the influence of the harmonics contained in the self-inductance and mutual inductance, and are added to the d-axis command voltage and the q-axis command voltage, respectively. This makes it possible to more precisely compensate for the delay. A specific method for calculating the d-axis inductor voltage and the q-axis inductor voltage will be described later in detail with reference to FIG. 3.

[0022] The control device 30 further supplies the d-axis and q-axis non-interference terms 36 to the adders A3 and A4, respectively. As a result, the adder A3 outputs the d-axis voltage V d * Similarly, the q-axis command voltage, the q-axis inductor voltage, and the dq-axis non-interacting term 36 are added together by an adder A4 to produce a q-axis voltage V q* is calculated and output. The calculated d-axis voltage V d * and the q-axis voltage V q * is supplied to the dq / UVW conversion unit 34.

[0023] The dq / UVW conversion unit 34 converts the d-axis voltage V d * and the q-axis voltage V q * The PWM signal generating unit 35 receives the converted three-phase voltage, and generates and outputs a PWM signal (i.e., a drive signal). The PWM signal is supplied to each of the switching elements 22a to 22f to control the three-phase AC motor 14.

[0024] Next, the configuration of the inductor voltage estimator 33 and the process executed by the inductor voltage estimator 33 will be described with reference to Fig. 3 and Fig. 4. As shown in Fig. 3, the inductor voltage estimator 33 includes an LPF (abbreviation of Low Pass Filter) 33a, a d-axis inductance map 33b, and a differentiator 33c. The LPF 33a calculates a d-axis current command value I d * and q-axis current command value I q * and removes the harmonic components to obtain the d-axis current command value I d * DC component I d_DC * , and the q-axis current command value I q * DC component I q_DC * The differentiator 33c outputs the d-axis current command value I d * and q-axis current command value I q * and the time derivative (d / dt) of each is calculated. d * ,(d / dt)I q * (i.e., the amount of change over time) is output.

[0025] The dq-axis inductance map 33b is a d-axis current command value I d * and q-axis current command value I q * , and the rotor angle θ, and calculate the instantaneous value L of the d-axis inductance. d * (t) and instantaneous value of q-axis inductance L q * (t) is calculated and output (S12 to S16 in FIG. 4). Specifically, the dq-axis inductance map 33b calculates and outputs the instantaneous value L d * (t) and instantaneous value of q-axis inductance L q * Calculate (t).

[0026] First, the self-inductance L of the coils 14U, 14V, and 14W of each phase of the three-phase AC motor 14 is calculated. U , L V , L W and mutual inductance M UV , M VW , M WU is expressed as follows:

[0027]

number

[0028] Here, the self-inductance L U is the self-inductance of the U-phase coil 14U. V is the self-inductance of the V-phase coil 14V. Self-inductance L W is the self-inductance of the W-phase coil 14W. The mutual inductance M UV is the mutual inductance between the U-phase coil 14U and the V-phase coil 14V. VW is the mutual inductance between the V-phase coil 14V and the W-phase coil 14W. WUis the mutual inductance between the W-phase coil 14W and the U-phase coil 14U.

[0029] In addition, in the above formula, L DC is the DC component of the self-inductance, L as_n is the amplitude of the n-th component of the self-inductance, φ Ln is the phase of the n-th component of the self-inductance, M DC is the DC component of the mutual inductance, M as_n is the amplitude of the n-th component of the mutual inductance, φ Mn is the phase of the n-th component of the mutual inductance. The summation (Σ) in the above formula is the summation with n as a bound variable, and n moves over all positive even numbers. Thus, the self-inductance L U , L V , L W and mutual inductance M UV , M VW , M WU contains harmonic components. Each parameter L DC ,L as_n ,φ Ln ,M DC ,M as_n , and φ Mn is the d-axis current I d DC component I d_DC and q-axis current I q DC component I q_DC Therefore, the d-axis inductance map 33b is a value that changes depending on the d-axis current I d DC component I d_DC and q-axis current I q DC component I q_DC With parameters, each parameter L DC ,L as_n ,φ Ln ,M DC ,M as_n , and φ Mn The self-inductance L U , L V , L W and mutual inductance M UV , M VW , M WU Figure 6 shows an example of the waveform of the self-inductance LU , L V , L W and mutual inductance M UV , M VW , M WU 6(a) and 6(b) and 6(c) show examples of the amplitude (see FIG. 6(a)) and phase (see FIG. 6(b) and (c)) of the harmonic components of the d-axis current I d DC component I d_DC and q-axis current I q DC component I q_DC Based on each parameter L DC ,L as_n ,φ Ln ,M DC ,M as_n , and φ Mn Select the map (or formula) to determine each of the above parameters L DC ,L as_n ,φ Ln ,M DC ,M as_n , and φ Mn is determined (S12 in FIG. 4).

[0030] Next, the dq-axis inductance map 33b calculates the self-inductance L U , L V , L W and mutual inductance M UV , M VW , M WU into the d-axis inductance and the q-axis inductance. Specifically, first, the dq-axis inductance map 33b receives the rotor angle θ from the rotation angle sensor 18 (S14 in FIG. 4). Next, the dq-axis inductance map 33b converts the 3-phase to 2-phase transformation matrix to X, the rotation coordinate transformation matrix to Y, and the inductance matrix to L, into (2 / 3)×XYLY T X T The (1, 1) and (2, 2) elements of the matrix expressed by the formula are the instantaneous value of the d-axis inductance L d * (t), instantaneous value of q-axis inductance L q * (t) (S16 in FIG. 4). Here, X T ,Y Tare the transposed matrices of matrices X and Y, respectively, and matrices X, Y, and L are defined by the following equations.

[0031]

number

[0032] Figure 7 shows the d-axis inductance L d and q-axis inductance L q FIG. 8 shows an example of the waveform of the d-axis inductance L d and q-axis inductance L q 8(a) and 8(b) show an example of the amplitude (see FIG. 8(a)) and phase (see FIG. 8(b)) of the harmonic components of the above.

[0033] Then, the instantaneous value L of the d-axis inductance, which is the output of the dq-axis inductance map 33b, d * (t) and the output of the differentiator 33c, (d / dt)I d * and the coefficient K d and are multiplied by multiplier M1 to obtain the d-axis inductor voltage V Ld * Similarly, the instantaneous value L of the q-axis inductance, which is the output of the dq-axis inductance map 33b, is calculated. q * (t) and the output of the differentiator 33c, (d / dt)I q * and the coefficient K q and are multiplied by multiplier M2 to produce the q-axis inductor voltage V Lq * That is, the d-axis inductor voltage V Ld * and the q-axis inductor voltage V Lq * are values ​​calculated using the following formulas.

[0034]

number

[0035] In addition, the above coefficient Kd ,K q is a coefficient used for the purpose of ensuring robustness against individual differences in products. In the modified example, the d-axis inductor voltage V Ld * and the q-axis inductor voltage V Lq * When calculating the coefficient K d ,K q may not be utilized.

[0036] The dq-axis inductance map 33b is the d-axis inductor voltage V Ld * and the q-axis inductor voltage V Lq * Once calculated, these are output (S20 in FIG. 4). As a result, the d-axis inductor voltage V Ld * is supplied to adder A3. The q-axis inductor voltage V Lq * is supplied to an adder A4 (see FIG. 2). In a situation where the superposition of harmonics on the current command value continues, the inductor voltage estimator 33 repeatedly executes the process of FIG. 4 (YES in S22 of FIG. 4: S10).

[0037] As shown in FIG. 9, in a comparative example in which the feedforward term is not calculated by the inductor voltage estimator 33 (i.e., a comparative example in which the inductor voltage estimator 33 is not provided), a delay occurs with respect to the command value (see the dashed and dotted lines in FIG. 9). In contrast, in this embodiment, the d-axis inductor voltage and the q-axis inductor voltage are estimated while considering the self-inductance and the mutual inductance, and these are added to the voltage command value as feedforward terms. As a result, as shown in FIG. 9, it is possible to improve the follow-up to the command value (see the dashed and solid lines in FIG. 9). Therefore, it is possible to suppress noise and vibration due to the operation of the three-phase AC motor 14. In particular, in the above embodiment, the feedforward term is considered while also including the harmonic components of the self-inductance and the mutual inductance, so that it is possible to further improve the follow-up to the command value.

[0038] Here, if noise or vibration occurs due to the operation of the three-phase AC motor 14, the noise or vibration is transmitted to the cabin of the electric vehicle 2, causing noise or vibration in the cabin of the electric vehicle 2. In particular, if an electromagnetic forcing force with a frequency component close to the resonance frequency of the transmission system from the three-phase AC motor 14 to the cabin of the electric vehicle 2 is generated, the generation of noise or vibration in the cabin becomes noticeable. The resonance frequency of the transmission system is a substantially constant value, but the frequency of each order of the electromagnetic forcing force changes according to the rotation speed of the three-phase AC motor 14. That is, in order to suppress the noise or vibration in the cabin, the d-axis DC current command value I d_DC * and q-axis DC current command value I q_DC * The order of the harmonic to be applied to varies depending on the rotation speed of the three-phase AC motor 14. Therefore, the dq-axis current command value generating unit 40 of this embodiment calculates the d-axis current command value I d * and q-axis current command value I q * By controlling this, the generation of noise or vibration inside the vehicle cabin is suppressed.

[0039] 10 and 11, the configuration of the dq-axis current command value generating unit 40 and the processing executed by the dq-axis current command value generating unit 40 will be described. As described above, the dq-axis current command value generating unit 40 generates the d-axis current command value I d * and q-axis current command value I q * and supplies these to the dq-axis voltage command calculation unit 32.

[0040] 10, the dq-axis current command value generating unit 40 includes a differentiator 41, a speed determining unit 42, a harmonic current map 43, and adders A5 and A6. The differentiator 41 receives the rotor angle θ detected by the rotation angle sensor 18, and calculates its time derivative (i.e., the rotation speed ω) (S110, S112 in FIG. 11). The speed determining unit 42 stores the resonant frequency band of the transmission system, receives the calculated rotation speed ω, and calculates the d-axis DC current command value I d_DC * and q-axis DC current command value I q_DC *The harmonic current map 43 selects the current amplitude and phase of the harmonic order from the map based on the determined harmonic order (S116 in FIG. 11). Then, the harmonic current map 43 calculates the d-axis DC current command value I d_DC * , q-axis DC current command value I q_DC * , and the rotor angle θ, and the d-axis DC current command value I d_DC * and q-axis DC current command value I q_DC * The harmonic components to be applied to each of the d-axis DC current command value I d_DC * The harmonic components to be added to the q-axis DC current command value I q_DC * The harmonic components to be added to the d-axis DC current command value I d_DC * and the harmonic components to be added to obtain the d-axis current command value I d * Similarly, the adder A6 calculates the q-axis DC current command value I q_DC * and the harmonic components to be added to obtain the q-axis current command value I q * (S120 in FIG. 11). The dq-axis current command value generating unit 40 repeatedly executes the process of FIG. 11 while the three-phase AC motor 14 continues to be driven (YES in S122 in FIG. 11: S110).

[0041] In this way, the dq-axis current command value generating unit 40 generates harmonic components of orders that can particularly contribute to suppressing vibrations in the vehicle cabin of the electric vehicle 2 caused by noise and vibrations due to the operation of the three-phase AC motor 14, by converting the harmonic components into d-axis DC current command values ​​I d_DC * and q-axis DC current command value I q_DC *This makes it possible to suppress vibrations in the vehicle interior.

[0042] In addition, the dq-axis current command value generating unit 40 outputs only the harmonic components of the orders that can particularly contribute to suppressing vibrations in the vehicle cabin as the d-axis DC current command value I d_DC * and q-axis DC current command value I q_DC * (i.e., it is not necessary to add harmonics of all orders), so that an increase in loss due to the flow of harmonic currents can be suppressed.

[0043] The control device 30 in the above embodiment is an example of a "control device" of the present technology. The U-phase coil 14U, the V-phase coil 14V, and the W-phase coil 14W in the above embodiment are an example of a "stator winding" of the present technology. The current sensor 16 and the rotation angle sensor 18 in the above embodiment are an example of a "current detection unit" and a "rotation angle detection unit" of the present technology, respectively. The UVW / dq conversion unit 31, the dq-axis voltage command calculation unit 32, the inductor voltage estimation unit 33, the adders A3 and A4, the dq / UVW conversion unit 34, the PWM signal generation unit 35, and the dq-axis current command value generation unit 40 in the above embodiment are an example of a "dq current conversion unit", a "dq command voltage calculation unit", a "dq inductor voltage calculation unit", an "addition unit", a "three-phase conversion unit", a "supply unit", and a "current command value generation unit" of the present technology, respectively.

[0044] A modification of the above embodiment will be described. The dq-axis current command value generating unit 40 does not need to have the harmonic current map 43. In this case, the dq-axis current command value generating unit 40 may add harmonics of all orders to the axis DC current command value and the q-axis DC current command value. [Explanation of symbols]

[0045] 2: electric vehicle, 10: battery, 12: capacitor, 14: three-phase AC motor, 14U: U-phase coil, 14V: V-phase coil, 14W: W-phase coil, 16: current sensor, 18: rotation angle sensor, 20: inverter, 22a to 22f: switching elements, 30: control device, 31: UVW / dq conversion unit, 32: dq-axis voltage command calculation unit, 33: inductor voltage estimation unit, 33a: differentiator, 33b: LPF, 33c: dq-axis inductance map, 34: dq / UVW conversion unit, 35: PWM signal generation unit, 36: dq-axis non-interference term, 40: dq-axis current command value generation unit, 41: differentiator, 42: speed determination unit, 43: harmonic current map, A1 to A6: adders, M1, M2: multipliers

Claims

1. A control device for a three-phase AC motor, comprising: a current detection unit that detects a current flowing through a stator winding of each phase of the three-phase AC motor; a rotation angle detection unit that detects a rotation angle of a rotor of the three-phase AC motor; a dq current converter that converts the current flowing through the stator winding of each phase, based on the detected rotation angle of the rotor, into a d-axis current and a q-axis current in a dq rotating coordinate system that rotates in synchronization with the rotation of the rotor; a dq command voltage calculation unit that calculates a d-axis command voltage and a q-axis command voltage based on a d-axis deviation, which is a deviation between a d-axis current command value and the d-axis current, and a q-axis deviation, which is a deviation between a q-axis current command value and the q-axis current; a three-phase conversion unit that receives the d-axis command voltage and the q-axis command voltage and converts them into a three-phase voltage; a supply unit that supplies power to the three-phase AC motor based on the three-phase voltage; Equipped with the d-axis current command value and the q-axis current command value each include a current harmonic component that is an integer multiple of a fundamental wave frequency of the current flowing through the stator winding, a dq inductor voltage calculation unit that calculates a d-axis inductor voltage based on a time change amount of the d-axis current command value that changes according to the rotation angle of the rotor and a d-axis inductance of the three-phase AC motor, and calculates a q-axis inductor voltage based on a time change amount of the q-axis current command value that changes according to the rotation angle of the rotor and a q-axis inductance of the three-phase AC motor; an adder that adds the d-axis inductor voltage and the q-axis inductor voltage to the d-axis command voltage and the q-axis command voltage, respectively; Further equipped with When the three-phase to two-phase transformation matrix is ​​X, the rotation coordinate transformation matrix is ​​Y, and the inductance matrix is ​​L, the d-axis inductance is (2 / 3)×XYLY. Ｔ X Ｔ The q-axis inductance is calculated as the (1, 1) component of the matrix expressed by the following equation: The inductance matrix L is the self-inductance L of each phase of the stator winding. U , L V , L W and mutual inductance M UV , M. VW , M. WU It consists of: The self-inductance L U , L V , L W and the mutual inductance M UV , M. VW , M. WU Each of the above includes an inductance harmonic component, The three-phase to two-phase transformation matrix X, the rotational coordinate transformation matrix Y, and the inductance matrix L are expressed by the following equations: [0010] A control device as defined in

2. a current command value generating unit that determines the d-axis current command value and the q-axis current command value based on a rotation speed of the three-phase AC motor, 2. The control device according to claim 1, wherein the current command value generating unit has a harmonic current map describing orders of the current harmonic components to be imparted to the d-axis current command value and the q-axis current command value, and their amplitudes and phases, using the rotational speed of the three-phase AC motor as a parameter.

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