Control method and control device for electric rotary motor and control system for electric rotary motor

Abstract

Control method for an electric rotary motor (MG100) for controlling an electric rotary motor (MG100) by PWM with a predetermined carrier frequency, wherein the method comprises the following: then, when an oscillation frequency in a natural oscillation of zero spatial order of the electric rotary motor (MG100) and a frequency of a frequency component of an electromagnetic excitation force that generates the natural oscillation overlap, switching a value of the carrier frequency from a first value to a second value that is different from the first value, wherein The tax procedure is characterized by the fact that the frequency of a frequency component of the electromagnetic excitation force fc ± 3f1, where the carrier frequency fc is and a rotational frequency of the electric rotary motor (MG100) is f1.

Description

Technical field

[0001] The present invention relates to a control device and a control method for an electric rotary motor and a control system for an electric rotary motor. Background area

[0002] Electric rotary motors, such as permanent magnet motors, exhibit natural oscillations that are dependent on the mechanical structures of the rotor, stator, and housing. Furthermore, due to fluctuations in the magnetic force between the rotor and stator, an electromagnetic excitation force is generated as the electric rotary motor rotates. When the frequency of the natural oscillation and the frequency of the electromagnetic excitation force overlap, resulting in resonance, a significant oscillation occurs within the electric rotary motor. Such oscillation produces noise and impairs user comfort.

[0003] A conventional technology for suppressing the occurrence of vibration in an electric rotary motor is the technology described in PTL 1. In the present technology, a resonant frequency is calculated based on the switching frequency of an inverter and the rotational frequency of a permanent magnet motor, and it is determined whether the calculated resonant frequency and a natural frequency of the permanent magnet motor coincide. Once it is determined that the resonant frequency and the natural oscillation frequency coincide, the switching frequency of the inverter is shifted to avoid the occurrence of resonance. Furthermore, PTL 2 discloses a method for operating a multiphase electric machine for vehicle propulsion. To reduce acoustic noise from the inverter, the pulse frequency of the PWM control is not kept constant but is continuously varied during operation. This distributes the acoustic noise energy over a wider frequency band, thereby reducing noise peaks and the excitation of mechanical resonances. PTL 3 describes a power inverter that varies the PWM carrier frequency for noise reduction. From a multitude of different carrier frequencies, one is selected and used for a randomly determined period of time before switching to the next.The method thus aims to improve the spectral distribution of electromagnetic noise and avoid the formation of interference components. Finally, PTL 4 describes a control method for an inverter to suppress motor noise, whereby the method identifies motor speeds at which sideband components of the PWM carrier frequency cause stator resonance. More precisely, when the motor speed approaches one of these critical ranges, the control system proactively switches to a different carrier frequency to avoid resonance excitation. List of prior art patent literature PTL1: JP 2007-020246 A PTL 2: DE 10 2009 049 055 A1 PTL 3: US 2016 / 111951 A1 PTL 4: JP 2009-284719 A Summary of the invention Technical problem statement

[0004] In the conventional technology described above, vibrations generated by electromagnetic excitation forces caused by structures such as a magnetic pole in the rotor, a tooth section where the winding in the stator is applied, and similar elements can be suppressed. However, this conventional technology does not account for the electromagnetic excitation forces caused by the harmonic component of the current flowing through the electric rotary motor. Therefore, reliably suppressing vibrations in the electric rotary motor is difficult, and significant vibrations can occur.

[0005] Therefore, the present invention provides a control method and a control device for an electric rotary motor that can reliably suppress vibration of the electric rotary motor, and a control system for an electric rotary motor. Solution to the problem

[0006] The problem is solved by a control method for an electric rotary motor with the features of claim 1, by a control device for an electric rotary motor with the features of claim 8, and by a control system for an electric rotary motor with the features of claim 9. Advantageous embodiments of the invention are the subject of the dependent claims. Advantageous effects of the invention

[0007] According to the present invention, an overlap of the oscillation frequency in the zero-order natural oscillation of the electric rotary motor and the frequency component of the electromagnetic excitation force that generates the natural oscillation is prevented by switching the carrier frequency. As a result, the occurrence of motor oscillation can be reliably prevented.

[0008] Problems, configurations and effects that differ from those described above are clarified by the description of embodiments below. Brief description of the drawings Fig. Figure 1 is a block diagram illustrating a control device for an electric rotary motor according to an embodiment of the present invention and a control system comprising the control device and the motor. Fig. Figure 2 is a schematic diagram illustrating the occurrence of vibration and a transmission path during motor control. Fig. Figure 3 illustrates a natural oscillation of a deformation of a motor stator during a motor oscillation. Fig. Figure 4 is a cross-sectional view illustrating the structure of a motor used in the present embodiment. Fig. Figure 5a illustrates waveforms of three-phase currents during motor control in the present embodiment. Fig. Figure 5b illustrates a frequency spectrum of a phase current. Fig. Figure 6 illustrates a relationship between frequency components of a motor phase current and a motor speed. Fig. Figure 7 illustrates a state in which an oscillation frequency peculiar to a motor structure overlaps with a frequency of the electromagnetic excitation force generated by a harmonic oscillation of the current and a rotating magnetic field of the motor. Fig. Figure 8a illustrates means for reducing noise and vibration of the motor in the present embodiment. Fig. Figure 8b illustrates means for reducing noise and vibration of the motor in the present embodiment. Fig. Figure 8c illustrates means for reducing noise and vibration of the engine in the present embodiment. Fig. Figure 8d illustrates means for reducing noise and vibration of the motor in the present embodiment. Description of the embodiments

[0009] First, an outline of an embodiment of the present invention is described.

[0010] According to the study by the inventor of the present invention, a natural oscillation of zero spatial order (ring-shaped mode), in which noise and vibration are more likely to occur, is generated by an electromagnetic excitation force with a frequency component fc ± 3f1 (fc: a carrier frequency of an inverter device and f1: a rotational frequency of the motor) of an electromagnetic excitation force caused by a carrier.

[0011] Furthermore, according to the study by the inventor of the present invention, the noise and the vibration become large when a point occurs where a vibration frequency in the natural oscillation of zeroth spatial order and the frequency fc ± 3f1 of the electromagnetic excitation force overlap.

[0012] Here, the frequency of the zeroth spatial order natural oscillation can be predicted or measured based on the motor's structure. Therefore, in the present embodiment, the carrier frequency is switched from fc_a to fc_b, which has a different magnitude than fc_a, when the zeroth spatial order natural oscillation frequency and an electromagnetic excitation force frequency fc_a ± 3f1 overlap, when the inverter device drives and controls the motor with a carrier frequency fc_a, and the motor is rotating at the rotational frequency f1. As a result, a region where the zeroth spatial order natural oscillation frequency f0 and the electromagnetic excitation force frequency fc_a ± 3f1 overlap—that is, a region where noise and vibration become high—is shifted to a region where the motor speed is low or to a region where the motor speed is high.More precisely, the present embodiment is as follows.

[0013] If a motor speed range to be used is a high-speed range, the range in which the oscillation frequency f0 in the zeroth spatial order natural oscillation and the frequency component of the electromagnetic excitation force caused by the carrier overlap is shifted into a low-speed range of the motor speed.

[0014] If the motor speed range to be used is the low-speed range, the range in which the oscillation frequency f0 in the zeroth spatial order natural oscillation and the frequency component of the electromagnetic excitation force caused by the carrier overlap is shifted into the high-speed range of the motor speed.

[0015] In this way, the noise and vibration generated by the motor can be reduced by shifting the area in which the oscillation frequency in the zeroth spatial order natural oscillation and the frequency component of the electromagnetic excitation force caused by the carrier overlap.

[0016] In the following, an embodiment of the present invention is described in detail with reference to the drawings.

[0017] Fig. Figure 1 is a block diagram illustrating a control device for an electric rotary motor (hereinafter referred to as the "motor") according to an embodiment of the present invention and a control system comprising the control device and the motor. In the present embodiment, the motor is installed in an electric vehicle or a hybrid vehicle.

[0018] An MG100 motor, for example, is a three-phase motor that includes a Y-connection, as shown in Fig. Figure 1 illustrates the motor MG100. It comprises a U-phase winding C110, a V-phase winding C120, and a W-phase winding C130. The windings C110, C120, and C130 are connected to a common star point N100. Furthermore, the motor MG100 is equipped with a rotary angle sensor R140 for detecting the rotation angle of the motor rotor. The motor MG100 is a permanent magnet synchronous motor or similar. The rotary angle sensor R140 is an encoder, a rotary encoder, or similar device.

[0019] The MG100 motor is driven by rotation, while a control current is supplied to the coil windings by an INV100 inverter using a battery (not illustrated) consisting of a secondary battery such as a lithium-ion battery or a nickel-hydrogen battery as a power source.

[0020] As described below, the INV100 inverter contains an INV200 arithmetic control device, an INV300 control circuit, and an INV400 power module.

[0021] The INV400 power module contains semiconductor power switching elements (hereinafter referred to as "switching elements"), each forming a U-phase branch, a V-phase branch, and a W-phase branch. The INV400 power module converts DC power from the battery into three-phase AC power by controlling the on / off timing of the switching elements. A switching operation of the INV400 power module, that is, an on / off operation of the switching elements, is controlled by a control signal from the INV300 control circuit. It should be noted that a bipolar insulated-gate transistor (IGBT) or a metal-oxide-semiconductor field-effect transistor (MOSFET) is used as the switching element.

[0022] The INV200 arithmetic control device generates a gate drive signal (an operating command) to control the switching time of the switching elements using pulse width modulation (hereinafter referred to as PWM) based on input information from another control device (host control device VCM100), a sensor, or the like. The INV300 control circuit generates a PWM gate pulse signal based on the gate drive signal and outputs this signal to the INV400 power module. The INV200 arithmetic control device contains a microcomputer for arithmetically processing the switching time. Input information to the microcomputer includes a required target torque value, a current value flowing through the MG100 motor, a rotor angle signal, the temperature of the INV400 power module, and similar parameters.

[0023] The target torque value (torque command) is input from the host control unit VCM100 to the arithmetic control unit INV200. For example, the host control unit VCM100 corresponds to a vehicle control unit that manages the entire vehicle, if the motor MG100 is a motor for driving a vehicle. The current flowing through the motor MG100 is detected by a current sensor CT100. The rotation angle of the motor MG100's rotor is detected by the rotation angle sensor R140 described above, and a detection signal (position information) from this is transmitted to the inverter INV100. The temperature of the power module INV400 (the temperature in the vicinity of the switching elements) is detected by a temperature sensor TS100.

[0024] The INV200 arithmetic control device calculates a current command value for a dq axis of the MG100 motor in a rotational coordinate system based on the target torque value. Based on the difference between the calculated current command value of the dq axis and a detected current value of the dq axis, it calculates a voltage command value for the dq axis. Furthermore, the INV200 arithmetic control device converts the calculated voltage command value of the dq axis into U-phase, V-phase, and W-phase voltage command values ​​based on the detected rotation angle. Furthermore, the arithmetic control device INV200 generates a pulse width modulated pulse signal based on a comparison between a fundamental wave (sine wave) based on the U-phase, V-phase and W-phase voltage command values ​​and a carrier wave (triangle wave) and outputs the generated pulse signal as the gate control signal to the control circuit INV300.The INV300 control circuit amplifies the gate control signal to generate the PWM gate pulse signal and outputs the generated gate control signal to the switching elements in the INV400 power module. As a result, the switching elements perform the switching operation.

[0025] Fig. Figure 2 is a schematic diagram illustrating the occurrence of vibration and a transmission path during motor control.

[0026] As in Fig. As illustrated in Figure 2, the rotating motor primarily experiences axial vibration (in an axial direction or a direction perpendicular to the axial direction) and electromagnetic noise (a vibration) in a radial direction. These vibrations are transmitted through a structure such as the stator and the motor housing and are further transmitted to the vehicle body via a mounting section between the motor and the vehicle body. Therefore, noise is generated when a large vibration occurs.

[0027] Axial vibration arises from a change in the gear engagement force of a reduction gear connected to a motor shaft, a twisting of the shaft, or similar factors. Furthermore, electromagnetic noise (vibration) in the radial direction arises from an excitation force caused by an electromagnetic force and exhibits a natural oscillation and natural frequency characteristic of a motor structure. It should be noted that the magnitude of the electromagnetic noise (vibration) in the radial direction varies depending on the operating point of the motor.

[0028] Here, the main causes (1) to (3) relating to the occurrence of noise and vibration during motor control are described. (1) The natural vibration and natural frequency of the engine structure system

[0029] Fig. Figure 3 illustrates the natural oscillation of the deformation of the motor stator during motor oscillation.

[0030] As in Fig. As illustrated in Figure 3, the deformation of the motor stator exhibits several natural frequencies and spatial natural states, each specified by spatial orders (e.g., zeroth spatial order, second order, fourth order, and the like). The smaller the spatial order, the greater the deformation (easier to induce oscillation) and the greater the amplitude of the motor oscillation.

[0031] The natural frequency of the natural vibration in such a motor deformation depends on the structure of the motor housing. Therefore, the frequency spectrum of the natural frequency does not change even if the motor speed increases over time. Furthermore, the natural frequency can be measured by an impact test using an impact hammer or similar device. (2) The frequency of the electromagnetic excitation force inherent in the motor structure system

[0032] Fig. Figure 4 is a cross-sectional view illustrating the structure of the motor used in the present embodiment. It should be noted that the illustrated motor is a so-called embedded magnet motor.

[0033] As in Fig. As illustrated in Figure 4, a stator 1 and a rotor 2 face each other with a predetermined gap between them. A winding 4 is wound around the teeth 3 of the stator 1. A permanent magnet 5 is provided in the rotor 2. When a three-phase alternating current flows through the winding 4 and a rotating magnetic field is generated, the rotor 2 rotates due to an interaction between the magnetic flux of the permanent magnet 5 and the rotating magnetic field.

[0034] The frequency of the electromagnetic excitation force inherent in the motor structure system is determined by the motor structure system and depends on the number of stator slots (the spaces between the teeth where the windings are arranged), the number of rotor magnet poles, and the like. In the motor that is in Fig. As illustrated in Figure 4, the number of slots is twelve, and the number of poles is four (the number of pole pairs is two). Therefore, the magnetic pole passes through the face of the teeth four times per phase of the three-phase alternating current, while the rotor 2 rotates mechanically once. Accordingly, the electromagnetic force acting on the rotor 2 changes four times. Therefore, the electromagnetic force changes twelve times for three phases. Due to such fluctuations in the electromagnetic force, a mechanical vibration occurs in the motor.

[0035] The frequency of the electromagnetic excitation force inherent in the motor structure system is expressed by a temporal order (rotational order) according to the time-dependent change of the electromagnetic force as described above. In the case of the motor that is in Fig. As illustrated in Figure 4, the electromagnetic excitation force is generated, which has the temporal orders (rotational orders) of the 12th, 24th order and the like.

[0036] As can be seen from the change in electromagnetic force described above, the frequency of the electromagnetic excitation force inherent to the motor structure system depends not only on the motor structure, such as the number of magnetic poles in the rotor and the number of slots in the stator, but also on the motor speed. Therefore, the frequency of the electromagnetic excitation force inherent to the motor structure system increases even within the same motor as the motor speed increases. (3) The electromagnetic excitation force caused by the carrier

[0037] The electromagnetic excitation force induced by the carrier is caused by an interaction between a harmonic oscillation of the current and a rotating magnetic field. Therefore, the frequency of the electromagnetic excitation force induced by the carrier depends on the carrier frequency, a secondary band wave of the carrier frequency, and the motor speed. Consequently, the frequency of the electromagnetic excitation force induced by the carrier changes such that it spreads radially around the carrier frequency as the motor speed increases, and converges to the carrier frequency as the motor speed decreases, provided the carrier frequency remains constant.

[0038] Therefore, the relationship between the carrier frequency, the carrier frequency's secondary band wave, and the motor speed is described with reference to Fig. 5a and Fig. 5b and Fig. 6 described.

[0039] Fig. Figure 5a illustrates waveforms of three-phase currents during motor control in the present embodiment. The horizontal and vertical axes represent time and current, respectively.

[0040] As in Fig. As illustrated in Figure 5a, frequency components derived from the carrier are superimposed on a fundamental frequency component (current frequency component) in the currents of the phases.

[0041] Fig. Figure 5b illustrates a frequency spectrum of a phase current that is in Fig. Figure 5a illustrates this. The horizontal and vertical axes represent the frequency and current, respectively. It should be noted that Fig. Figure 5b illustrates a result of analyzing the U-phase current by a fast Fourier transform.

[0042] As in Fig. As illustrated in 5b, a fundamental frequency component (f1) and secondary band waves (fc ± 2f1 and fc ± 4f1) of the carrier frequency (fc) appear in the frequency spectrum of the phase current in the present embodiment.

[0043] It is generally known that in a PWM inverter, the frequency component of the fundamental frequency and the sidebands of the carrier frequency (frequencies: fc ± 2f1 and fc ± 4f1 or the like) appear (fc: the carrier frequency and f1: the fundamental frequency (current frequency)) when a Fourier analysis is performed on a motor phase current (or a line voltage) in a sinusoidally modulated signal. Therefore, in the present embodiment, a similar analysis result is obtained as in Fig. 5b is illustrated.

[0044] Fig. Figure 6 illustrates a relationship between frequency components of the motor phase current and the motor speed, as shown in Fig. 5a and Fig. Figure 5b illustrates this. The horizontal and vertical axes represent the frequency and motor speed, respectively. Fig. 6. fc is the carrier frequency, and f1 is the current frequency. Furthermore, fc ± 2f1 and fc ± 4f1 are the frequencies of the sideband waves (harmonic oscillations of the current), and f1 is the current frequency during motor control.

[0045] Since the current frequency f1 changes according to the motor speed, the frequencies (fc ± 2f1 and fc ± 4f1) of the secondary band waves change such that they propagate radially around the carrier frequency (fc), as shown in Fig. Figure 6 illustrates this. Therefore, the frequencies (fc ± 2f1 and fc ± 4f1) of the secondary band waves increase radially and decrease by a carrier frequency fc_1, which is set in the inverter, when the motor speed increases, i.e., when the current frequency f1 increases. Conversely, the frequencies (fc ± 2f1 and fc ± 4f1) of the secondary band waves approach the carrier frequency fc_1 when the motor speed decreases, i.e., when the current frequency f1 decreases.

[0046] It should be noted that in the event of a change in the carrier frequency during inverter operation, spurious band waves appear after the change around the carrier frequency, which behave similarly with respect to f1 as in Fig. Change 6.

[0047] If two or three of the causes (1) to (3) above overlap, the noise and vibration generated by the motor will be significant. Of the causes (1) to (3), a case where (1) and (3) overlap is considered in the present embodiment.

[0048] According to the inventor's study of the present invention, the noise and vibration generated by the motor appear strong when the natural frequency of the motor structure system and the frequency of the electromagnetic excitation force caused by the support overlap. Furthermore, according to the inventor's study of the present invention, the noise and vibration generated by the motor are particularly strong when the natural frequency of the motor structure system is of zero spatial order and the frequency of the electromagnetic excitation force caused by the support is fc ± 3f1.

[0049] The following is an outline of an analysis in the study by the inventor of the present invention described above.

[0050] First, the rotating magnetic field generated by the rotor magnet is expressed by expression (1). Bread⋅sin(pθ−ω1⋅t)

[0051] In expression (1), Brot: magnetic flux density, p: a coefficient, θ: a phase, ω1: an angular frequency of the current, and t: time.

[0052] The rotating magnetic field of the stator mainly comprises a rotating magnetic field due to the fundamental wave component of the current flowing through the stator winding, and a rotating magnetic field due to a harmonic component of the current flowing through the stator coil. Therefore, the former is expressed by expression (2), and the latter is expressed by expression (3). Bsta⋅sin(pθ−ω1t)

[0053] In expression (2), Bsta: magnetic flux density, p: a coefficient, θ: a phase, ω1: an angular frequency of the current, and t: time. Bpwm⋅sin{pθ+(ωc+2ω1)t}+Bpwm⋅sin{pθ+(ωc+4ω1)t}+Bpwm⋅sin{pθ−(ωc−2ω1)t}+Bpwm⋅sin{pθ−(ωc+4ω1)t}

[0054] In expression (3), Bpwm: magnetic flux density, p: a coefficient, θ: a phase, ωc: an angular frequency of the carrier, ω1: an angular frequency of the current, and t: time.

[0055] As described above ( Fig. 5), due to the harmonic component of the current, as expressed by expression (3), similar frequency components (ωc ± 2 ω1 and ωc ± 4 ω1 (ωc = 2πfc and ω1 = 2πf1)) are present in the rotating magnetic field, since the harmonic component of the current flowing through the windings of the stator contains the components (fc ± 2f1 and fc ± 4f1) of the spurious band waves of the carrier frequency fc.

[0056] Here, the electromagnetic excitation force in the radial direction is generated by the interaction between the rotating magnetic field through the rotor and the rotating magnetic field through the stator. Therefore, the magnitude of the electromagnetic excitation force is considered to be proportional to {expression (1) × (expression (2) + (expression (3))}. Thus, {expression (1) × (expression (2) + (expression (3))} is calculated using the additive theorem of the trigonometric function sinα·sinβ =-(1 / 2)·(cos(α+β)-cos(α-β))), and the sum of expressions (4) to (8) is obtained. Bread⋅Bsta×(−(1 / 2)⋅cos(2pθ−2ω1t)+(1 / 2)) Bread⋅Bpwm×(−(1 / 2)⋅cos(2pθ+(ωc+ω1)t)+(1 / 2)⋅cos(0θ−(ωc+3ω1)t)) Bread⋅Bpwm×(−(1 / 2)⋅cos(2pθ+(ωc−5ω1)t)+(1 / 2)⋅cos(0θ−(ωc+3ω1)t)) Bread⋅Bpwm×(−(1 / 2)⋅cos(2pθ−(ωc−ω1)t)+(1 / 2)⋅cos(0θ+(ωc−3ω1)t)) Bread⋅Bpwm×(−(1 / 2)⋅cos(2pθ−(ωc+5ω1)t)+(1 / 2)⋅cos(0θ+(ωc+3ω1)t))

[0057] Focusing on the above expressions (5) to (8), it is noted that a component is included in which the angle is expressed by expression (9). 0θ±2π(ωc±3ω1)t

[0058] In expression (9), “Oθ” corresponds to a distortion of the zeroth spatial order natural oscillation, and “ωc ± 3ω1” is considered to have a component corresponding to the frequency “fc ± 3f1” (ωc = 2πfc and ω1 = 2nf1). That is, if the frequency of the electromagnetic excitation force is “fc ± 3f1”, the zeroth spatial order natural oscillation is estimated to occur.

[0059] In expressions (5) to (8) above, “2pθ” corresponds to a distortion of a higher-order natural frequency than the zeroth spatial order natural frequency, and the frequencies of the harmonic oscillation of the current (the carrier frequency's sideband waves) are considered at this point to be “fc ± f1” and “fc ± 5f1”. According to the inventor's study of the present invention, it is less likely that the noise and vibration due to these distortions of a higher-order natural frequency are caused by the excitation force due to the harmonic oscillation of the current, and thus they are smaller than those in the zeroth spatial order natural frequency.

[0060] When two or three of the causes (1) to (3) mentioned above overlap, the noise and vibration generated by the motor become significant. Therefore, in the present embodiment, means are provided, in particular, to reduce the noise and vibration through the motor's control system when causes (1) and (3) overlap. These means are described below. First, the noise and vibration that increase when the frequencies overlap in cases (1) and (3) are described.

[0061] Fig. Figure 7 illustrates a state in which the oscillation frequency inherent to the motor structure and the frequency of the electromagnetic excitation force generated by the harmonic oscillation of the current (the secondary band wave of the carrier frequency) and the rotating magnetic field of the motor overlap.

[0062] In Fig. 7 are fc, fc ± f1, fc ± 2f1 and fc ± 3f1 frequency components of the electromagnetic excitation force generated by the rotating magnetic field and the harmonic oscillations of the current. Furthermore, f0 is the natural frequency in the natural oscillation (zeroth spatial order) that is characteristic of the motor structure system.

[0063] Furthermore, in Fig. 7. The rotational orders of the electromagnetic excitation force (Nth order rotation and 2Nth order rotation) are the electromagnetic excitation frequencies inherent to the motor structure system and depend on the number of slots, the number of magnets, and the like, as described above. Furthermore, the electromagnetic excitation frequency depends on the motor speed and becomes low when the motor speed is low and high when the motor speed is high.

[0064] As described above, the electromagnetic excitation force generated by the rotating magnetic field and the harmonic oscillations of the current (fc ± 4f1 and fc ± 2f1) has a frequency component with a relatively large oscillation, which is the frequency fc ± 3f1 in the natural oscillation of zeroth spatial order. Fig. Figure 7 illustrates that the frequencies fc - 3f1 and f0 coincide at the rotational speed at a point P_1. That is, when the motor is driven with the carrier frequency fc_1, and the rotational frequency f1 is a value at point P_1, the oscillation frequency (f0), which is inherent to the motor structure, and the electromagnetic excitation force (fc - 3f1), which is generated by the harmonic oscillation of the current and the rotating magnetic field of the motor, coincide. In such a motor speed range near point P_1, an overlap of frequencies is likely to occur, and the noise and vibration will be correspondingly large.

[0065] When frequencies in the human hearing range (20 Hz to 20 kHz) overlap, passenger comfort decreases, especially in a certain speed range (mode FTP 75: approximately 1000 to 5000 rpm). -1 ) which is frequently used.

[0066] In Fig. 7. The electromagnetic excitation frequency, which is characteristic of the motor structure system, also coincides with f0 in the 2N-th order rotation. In this case, the noise and vibration become exceptionally large.

[0067] In the present embodiment, the noise and vibration of the motor are reduced by suppressing the overlap of the vibration frequency inherent in the motor structure and the frequency of the electromagnetic excitation force caused by the harmonic oscillation of the current and the rotating magnetic field of the motor, as described above. Means for reducing the noise and vibration of the motor in the present embodiment are described below.

[0068] Fig. 8a, Fig. 8b, Fig. 8c and Fig. Figure 8d illustrates means for reducing noise and vibration of the motor in the present embodiment. It should be noted that in Fig. 8a to 8d, similar to those in Fig. 7, fc, fc ± f1, fc ± 2f1 and fc ± 3f1 are frequency components of the electromagnetic excitation force generated by the rotating magnetic field and the harmonic oscillations of the current, f0 is the natural frequency in the natural oscillation (zeroth spatial order) that is peculiar to the motor structure system, and the rotational orders of the electromagnetic excitation force (rotation Nth order and rotation 2Nth order) are the electromagnetic excitation frequencies that are peculiar to the motor structure system.

[0069] In each of the means that are in Fig. 8a, Fig. 8b, Fig. 8c and Fig. 8d are illustrated by the arithmetic control device (INV200 in Fig. 1) Determines whether the frequency fc ± 3f1 of the electromagnetic excitation force generated by the rotating magnetic field and the harmonic oscillation of the current coincides with the frequency f0 in the natural oscillation with spatial order 0. If it is determined that fc ± 3f1 coincides with f0, a value of the carrier frequency fc is switched from a first value to a second value. Here, f0 is measured by a percussion test or the like, and a measured value is preset in the arithmetic control device. It should be noted that the rotational frequency f1 is calculated by the arithmetic control device based on the rotation angle of the motor's rotor, which is measured by the rotation angle sensor (R140 in Fig. 1) is detected.

[0070] When PWM is used as the motor control method, the number of data samples is preferably 10 or more to obtain a suitable current control response. Therefore, maintaining the relationship fc / f1 > 10 before and after switching the carrier frequency is preferred. Furthermore, the carrier frequency is set to a value different from the oscillation frequency inherent in the motor structure, and preferably to a separate value. As a result, fc ± 3f1 and f0 approach each other again after switching the carrier frequency, thus suppressing an increase in motor noise and vibration.

[0071] It should be mentioned that a power loss caused by the semiconductor power switching elements in the INV400 power module ( Fig. 1) is generated, increases when the carrier frequency becomes high, such that it is preferable to adjust the carrier frequency taking into account the power loss and the heat generation that accompanies the power loss.

[0072] The following section describes individual resources.

[0073] The agent that is in Fig. As illustrated in Figure 8a, the carrier frequency on one side is switched to a higher frequency than the natural frequency inherent in the motor structure system, such that the overlap of the natural frequency and the frequency of the electromagnetic excitation force caused by the carrier is moved to a side with a lower rotational speed.

[0074] If the motor is driven and controlled with the carrier frequency fc_1, which is a higher frequency than the natural frequency f0, as in Fig. As illustrated in Figure 8a, the oscillation frequency f0, which is characteristic of the motor structure, and the frequency fc - 3f1 (fc = fc_1) of the electromagnetic excitation force, caused by the harmonic oscillation of the current (the secondary band wave of the carrier frequency) and the rotating magnetic field of the motor, coincide at point P_1. At this time, the noise and oscillation of the motor become large in the vicinity of point P_1.

[0075] Here, the carrier frequency is switched from fc_1 to fc_2, which is higher than f0 and lower than fc_1. As a result, the point at which the natural frequency f0 and the frequency fc - 3f1 of the electromagnetic excitation force, generated by the harmonic oscillation of the current (the secondary band wave of the carrier frequency) and the rotating magnetic field of the motor, coincide, moves from P_1 to the point P_2, where the motor speed is lower than at P_1.

[0076] By switching the carrier frequency from fc_1 to fc_2, the overlap of the natural frequency inherent to the motor structure and the electromagnetic excitation frequency caused by the carrier—that is, the range in which noise and vibration become high—is shifted to the lower speed range. Therefore, by controlling the motor with the carrier frequency fc_2, the noise and vibration generated by the motor can be reduced, even when the motor speed is set to a medium to high speed range.

[0077] It should be mentioned that the electromagnetic excitation frequency, which is peculiar to the motor structure system, is in the 2N-th order rotation at point P_1 in Fig. 8a also coincides with f0. In this case, the noise and vibration of the motor become exceptionally large. Therefore, by switching the carrier frequency, the range in which the natural frequency, the frequency of the electromagnetic excitation force caused by the carrier, and the electromagnetic excitation frequency inherent to the motor structure system overlap is shifted to the side with lower speed. Therefore, the noise and vibration can be significantly reduced.

[0078] Next, the carrier frequency of the agent that is in Fig. Figure 8b illustrates that on one side with a higher frequency than the natural frequency inherent in the motor structure system, the system is switched in such a way that the overlap of the natural frequency and the frequency of the electromagnetic excitation force caused by the carrier is moved to a side with high rotational speed.

[0079] If the motor is driven and controlled with the carrier frequency fc_1, which is a higher frequency than the natural frequency f0, as in Fig. As illustrated in Figure 8b, the oscillation frequency f0, which is characteristic of the motor structure, and the frequency fc - 3f1 (fc = fc_1) of the electromagnetic excitation force, caused by the harmonic oscillation of the current (the secondary band wave of the carrier frequency) and the rotating magnetic field of the motor, coincide at point P_1. At this time, the noise and oscillation of the motor become large in the vicinity of point P_1.

[0080] Here, the carrier frequency is switched from fc_1 to fc_3, which is higher than f0 and higher than fc_1. As a result, the point at which the natural frequency f0 and the frequency fc - 3f1 of the electromagnetic excitation force, generated by the harmonic oscillation of the current (the secondary band wave of the carrier frequency) and the rotating magnetic field of the motor, coincide, is moved from P_1 to the point P_3, where the motor speed is higher than at P_1.

[0081] By switching the carrier frequency from fc_1 to fc_3, the overlap of the natural frequency inherent to the motor structure system and the electromagnetic excitation frequency caused by the carrier—that is, the range in which noise and vibration become high—is shifted towards the high-speed side. Therefore, by controlling the motor with the carrier frequency fc_3, the noise and vibration generated by the motor can be reduced, even when the motor speed is set to a low to medium speed range.

[0082] It should be mentioned that the electromagnetic excitation frequency, which is peculiar to the motor structure system, is in the 2N-th order rotation at point P_1 in Fig. 8b also coincides with f0. In this case, the noise and vibration of the motor become exceptionally large. Therefore, by switching the carrier frequency, the range in which the natural frequency, the frequency of the electromagnetic excitation force caused by the carrier, and the electromagnetic excitation frequency inherent to the motor structure system overlap is shifted to the side with high rotational speed. Therefore, the noise and vibration can be significantly reduced.

[0083] Next, the carrier frequency of the agent that is in Fig. Figure 8c illustrates that the system is switched such that the overlap of the natural frequency and the frequency of the electromagnetic excitation force caused by the carrier is moved to a side with a lower rotational speed, similar to the device in Figure 8c. Fig. 8a, however, the carrier frequency differs from the mean in Fig. 8a after switching to a lower frequency than the natural frequency.

[0084] If the motor is driven and controlled with the carrier frequency fc_1, which is a higher frequency than the natural frequency f0, as in Fig. As illustrated in Figure 8c, the oscillation frequency f0, which is characteristic of the motor structure, and the frequency fc - 3f1 (fc = fc_1) of the electromagnetic excitation force, caused by the harmonic oscillation of the current (the secondary band wave of the carrier frequency) and the rotating magnetic field of the motor, coincide at point P_1. At this point, the noise and vibration of the motor in the vicinity of point P_1 become significant.

[0085] Here, the carrier frequency is switched from fc_1 to fc_4, which is lower than f0. In this case, the point P_2, where the natural frequency f0 and the frequency fc + 3f1 of the electromagnetic excitation force generated by the harmonic oscillation of the current (the secondary band wave of the carrier frequency) and the rotating magnetic field of the motor coincide, is located on a side with a lower motor speed than at P_1.

[0086] By switching the carrier frequency from fc_1 to fc_4, the overlap between the natural frequency inherent to the motor structure and the electromagnetic excitation frequency caused by the carrier—that is, the range in which noise and vibration become high—is shifted towards the lower speed range. Therefore, by controlling the motor with the carrier frequency fc_4, the noise and vibration generated by the motor can be reduced, even when the motor speed is set to a medium to high speed range.

[0087] It should be mentioned that the electromagnetic excitation frequency, which is peculiar to the motor structure system, is in the 2N-th order rotation at point P_1 in Fig. 8c also coincides with f0. In this case, the noise and vibration of the motor become exceptionally high. Therefore, by switching the carrier frequency, the range in which the natural frequency, the frequency of the electromagnetic excitation force caused by the carrier, and the electromagnetic excitation frequency inherent to the motor structure system overlap is shifted towards the lower speed side. Therefore, the noise and vibration can be significantly reduced.

[0088] Next, the carrier frequency of the agent that is in Fig. Figure 8d illustrates that, after switching to a lower frequency than the natural frequency, the result is similar to the mean in Fig. 8c, however, the carrier frequency is switched in such a way that the overlap of the natural frequency and the frequency of the electromagnetic excitation force caused by the carrier is, unlike the mean in Fig. 8c is moved to one side at high speed.

[0089] If the motor is driven and controlled with the carrier frequency fc_1, which is a higher frequency than the natural frequency f0, as in Fig. As illustrated in Figure 8d, the oscillation frequency f0, which is characteristic of the motor structure, and the frequency fc - 3f1 (fc = fc_1) of the electromagnetic excitation force, caused by the harmonic oscillation of the current (the secondary band wave of the carrier frequency) and the rotating magnetic field of the motor, coincide at point P_1. At this time, the noise and vibration of the motor in the vicinity of point P_1 become significant.

[0090] Here, the carrier frequency is switched from fc_1 to fc_5, which is lower than f0. In this case, the point P_5, where the natural frequency f0 and the frequency fc + 3f1 of the electromagnetic excitation force generated by the harmonic oscillation of the current (the secondary band wave of the carrier frequency) and the rotating magnetic field of the motor coincide, is located on a side with a higher motor speed than at P_1. It should be noted that when the values ​​of f0 and fc_1 in Fig. 8c equals the values ​​of f0 and fc_1, respectively. Fig. 8d are, fc_5 ( Fig. 8d) a lower frequency than fc_4 ( Fig. 8c).

[0091] By switching the carrier frequency from fc_1 to fc_5, the overlap between the natural frequency inherent to the motor structure and the electromagnetic excitation frequency caused by the carrier—that is, the range in which noise and vibration are high—is shifted towards the high-speed side. Therefore, by controlling the motor with the carrier frequency fc_5, the noise and vibration generated by the motor can be reduced, even when the motor speed is set to a low to medium speed range.

[0092] It should be mentioned that the electromagnetic excitation frequency, which is peculiar to the motor structure system, is in the 2N-th order rotation at point P_1 in Fig. 8d also coincides with f0. In this case, the noise and vibration of the motor become exceptionally high. Therefore, by switching the carrier frequency, the range in which the natural frequency, the frequency of the electromagnetic excitation force caused by the carrier, and the electromagnetic excitation frequency inherent to the motor structure overlap is shifted towards the lower speed side. Therefore, the noise and vibration can be significantly reduced.

[0093] The funds that are in Fig. The components described in sections 8a to 8d can be selected appropriately according to the natural frequency, the magnitude of the carrier frequency, and the motor speed to be used. It should be noted that in the case of switching the carrier frequency to a carrier frequency lower than the natural frequency, as described in section 8a to 8d, the following applies: Fig. 8c and Fig.Figure 8d illustrates that the range where noise and vibration become large can be moved to the range where the motor speed is low and to the range where the motor speed is high without increasing the power loss and heat generation of the inverter device.

[0094] As described above, according to the present embodiment, the carrier frequency is switched such that the range in which the oscillation frequency f0 in the zeroth spatial order natural oscillation and the frequency component fc ± 3f1 of the electromagnetic excitation force overlap is moved to the range in which the motor speed is low or to the range in which the motor speed is high when the motor is rotating at the predetermined rotational frequency f1. As a result, the noise and vibration generated by the motor can be reduced.

[0095] Furthermore, according to the present embodiment, the carrier frequencies are set before and after switching according to an estimable or measurable vibration frequency f0 in the natural frequency of the 0th spatial order, whereby a motor control can be implemented to reliably reduce the noise and vibration generated by the motor. Therefore, it is not necessary to carry out a complicated investigation such as prototype testing of a motor control system, evaluation of noise and vibration, and adjustment of the motor control system configuration based on an evaluation result.

[0096] Furthermore, according to the present embodiment, a design consideration with a high degree of freedom is possible, such as preferably implementing countermeasures to reduce noise and vibration in the engine speed range with a high usage frequency (e.g. in accordance with a specified driving mode).

[0097] It should be noted that the present invention is not limited to the embodiments described above and includes various modifications. For example, the embodiments described above have been described in detail to make the present invention easily understandable, and the present invention is not necessarily limited to one that includes all the described configurations. Furthermore, another configuration can be added to, deleted from, or replaced by a part of any given configuration of the embodiments. List of reference symbols VCM100 Host Control Unit INV100 Inverter INV200 arithmetic control device INV300 control circuit INV400 power module CT100 current sensor TS100 temperature sensor MG100 engine C110 U-phase coil winding C120 V-phase coil winding C130 W-phase coil winding N100 star point R140 rotary angle sensor 1 Stator 2 Rotor 3 teeth 4 windings 5 permanent magnets

Claims

[1] Control method for an electric rotary motor (MG100) for controlling an electric rotary motor (MG100) by PWM with a predetermined carrier frequency, wherein the method comprises: then, when an oscillation frequency in a natural oscillation of zero spatial order of the electric rotary motor (MG100) and a frequency of a frequency component of an electromagnetic excitation force that generates the natural oscillation overlap, switching a value of the carrier frequency from a first value to a second value that is different from the first value, wherein the tax procedure characterized by is that the frequency of a frequency component of the electromagnetic excitation force fc ± 3f1, where the carrier frequency fc is and a rotational frequency of the electric rotary motor (MG100) is f1. [2] Control method for an electric rotary motor (MG100) according to claim 1, wherein when an oscillation frequency in a natural oscillation of zero spatial order of the electric rotary motor (MG100) and a frequency of a frequency component of the electromagnetic excitation force generating the natural oscillation overlap, a value of a rotational frequency for the second value is lower than a value of a rotational frequency for the first value. [3] Control method for an electric rotary motor (MG100) according to claim 2, wherein the first value is higher than the oscillation frequency in the natural oscillation, and the second value is lower than the first value and higher than the oscillation frequency in the natural oscillation. [4] Control method for an electric rotary motor (MG100) according to claim 2, wherein the first value is higher than the oscillation frequency in the natural oscillation, and the second value is lower than the first value and lower than the oscillation frequency in the natural oscillation. [5] Control method for an electric rotary motor (MG100) according to claim 1, wherein when an oscillation frequency in a natural oscillation of zero spatial order of the electric rotary motor (MG100) and a frequency of a frequency component of the electromagnetic excitation force generating the natural oscillation overlap, a value of a rotational frequency for the second value is higher than a value of a rotational frequency for the first value. [6] Control method for an electric rotary motor (MG100) according to claim 5, wherein the first value is higher than the oscillation frequency in the natural oscillation, and the second value is higher than the first value. [7] Control method for an electric rotary motor (MG100) according to claim 5, wherein the first value is higher than the oscillation frequency in the natural oscillation, and the second value is lower than the first value and lower than the oscillation frequency in the natural oscillation. [8] Control device for an electric rotary motor (MG100) for controlling an electric rotary motor (MG100) by PWM with a predetermined carrier frequency, the device comprising: a power module (INV400) configured to output three-phase AC power to drive the electric rotary motor (MG100) by switching a semiconductor switching element ON / OFF; a control circuit (INV300) configured to generate a PWM gate pulse to switch the semiconductor switching element ON / OFF; and an arithmetic control device (INV200) configured to generate a gate drive signal that instructs the drive circuit (INV300) to generate the PWM gate pulse by PWM with the specified carrier frequency, wherein The arithmetic control device (INV200) determines whether an oscillation frequency in a natural oscillation of zero spatial order of the electric rotary motor (MG100) and a frequency component of an electromagnetic excitation force generating the natural oscillation overlap and switches a carrier frequency value from a first value to a second value different from the first value when the overlap is determined, wherein the control device characterized by is that the frequency of a frequency component of the electromagnetic excitation force fc ± 3f1, where the carrier frequency fc is and a rotational frequency of the electric rotary motor (MG100) is f1. [9] Control system for an electric rotary motor (MG100) comprising the following: an electric rotary motor (MG100); and an inverter (INV100) configured to control the electric rotary motor (MG100), wherein the inverter (INV100) consists of the control device for an electric rotary motor (MG100) according to claim 8.

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