JP6424536B2 - Motor controller - Google Patents

Description

  The present invention relates to a motor control device that controls a switched reluctance motor.

  As a motor control device for controlling a switched reluctance motor (hereinafter referred to as an SR motor), one that controls the current flowing in a coil is known as seen in Patent Document 1 below. Specifically, in the control device described in Patent Document 1, at the time of switching on / off of energization of the coil, the current value to be supplied to the coil, the rotational position of the rotor at each rotational position according to the rotational speed of the rotor. A rising waveform to the current value when turning on and a falling waveform from the current value when turning off are calculated. Then, the current target value is set according to the current value, the rising waveform, and the falling waveform. By performing such control, the change width of the magnetic flux at the time of on / off switching becomes small, and it becomes possible to suppress vibration and to reduce the level of noise.

Patent No. 3255167

  The technique described in Patent Document 1 does not consider the magnetic saturation of the coil. For this reason, in the non-linear region where the inductance changes according to the current, the accuracy of current control is reduced, and the effect of reducing vibration and noise becomes insufficient. Further, while it is possible to suppress a sharp change of the magnetic flux φ, it is not possible to suppress the pulsation of the radial force, and the effect of reducing the vibration and the noise is insufficient.

  Therefore, it is conceivable to control the magnetic flux φ by adjusting the voltage applied to the coil instead of controlling the current flowing through the coil. By adjusting the voltage applied to the coil, it becomes possible to directly control the magnetic flux φ generated in the coil. By directly controlling the magnetic flux φ, noise and vibration can be sufficiently reduced even in the above-described non-linear region, and pulsation of radial force can be suppressed. Here, in the case of controlling the magnetic flux φ by adjusting the voltage applied to the coil, there is a demand for suppressing vibration and noise having a specific cycle for the purpose of suppressing resonance and the like.

  The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a control device capable of preferably suppressing noise and vibration having a specific cycle in an SR motor.

  The present invention provides a voltage output circuit (20) in a switched reluctance motor having a stator having a coil (22) and a rotor rotatably supported and rotated by applying a voltage to the coil. A motor control unit (30) for controlling the motor by adjusting an output voltage output from the coil to the coil, wherein a voltage is applied to the coil in one cycle of an electrical angle of the motor Basic command voltage setting means (30) for setting a basic command voltage so that the interlinkage magnetic flux generated in the coil has a predetermined predetermined waveform, and a sine wave voltage having a specific cycle different from one cycle of the electrical angle The superimposing means for superposing on the basic command voltage and setting the output voltage of the voltage output circuit as a command voltage for commanding the output voltage of the voltage output circuit based on the command voltage Characterized in that it comprises a voltage control means for controlling the pressure (30), the.

  The radial force Fr of the SR motor can be expressed using K (θ) determined from the shape of the stator and the shape of the rotor, and the magnetic flux φ (Fr (θ) = K (θ) · φ ^ 2) . In the present invention, the magnetic flux φ is controlled by adjusting the voltage applied to the coil. Therefore, a sine wave voltage having a specific cycle different from one cycle of the rotation angle is superimposed on the command voltage. This makes it possible to reduce the radial force having that particular cycle by reducing the magnetic flux having that particular cycle (φ = ∫vdt). Thereby, vibration and noise of a specific cycle can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS The block diagram of the control system of SR motor concerning embodiment. The figure which shows the setting method of the command voltage concerning embodiment. The figure which illustrates the time-dependent change of the electric current which flows into the coil concerning embodiment. The flowchart which shows the procedure of the modulated wave generation process which becomes the premise of embodiment. The flowchart which shows the procedure of the voltage control process concerning embodiment. The figure which shows the closed circuit formed at the time of the positive voltage application concerning embodiment. The figure which shows the closed circuit formed at the time of the negative voltage application concerning embodiment. The timing chart which shows an example of the pulse width modulation concerning an embodiment. The figure which shows the basic command voltage, the magnetic flux, the waveform of a coefficient and radial force, and the order component of a radial force at the time of applying a basic command voltage to a coil. The functional block diagram of a modulation wave generation part. The flowchart which shows the procedure of the modulated wave generation process concerning embodiment. The figure which shows the command voltage, the magnetic flux, the waveform of a coefficient and radial force, and the order component of radial force at the time of superimposing a harmonic voltage. The flowchart which shows the procedure of the modulated wave generation processing concerning a modification. The figure which shows the waveform of the basic command voltage concerning a modification.

First Embodiment
Hereinafter, a first embodiment in which a motor control device is applied to a switched reluctance motor (hereinafter, SR motor) as a vehicle-mounted main machine will be described with reference to the drawings.

  As shown in FIG. 1, the high voltage battery 10 is a secondary battery having a terminal voltage of, for example, 100 V or more (288 V). In addition, as the high voltage battery 10, for example, a lithium ion secondary battery or a nickel hydrogen secondary battery can be used.

  A power conversion circuit 20 (voltage output circuit) is connected to the high voltage battery 10 via a smoothing capacitor 12. To the power conversion circuit 20, a motor generator as an on-vehicle main machine is connected. The motor generator is an SR motor. The SR motor has a stator having a coil 22 and a rotor that is rotatably supported and that rotates when a voltage is applied to the coil 22. Specifically, in the present embodiment, a three-phase SR motor including a U-phase coil 22 u, a V-phase coil 22 v, and a W-phase coil 22 w is used as the SR motor. Further, the rotor of the SR motor of this embodiment has six poles, and the rotation angle (mechanical angle) of 60 degrees of the SR motor corresponds to the electrical angle of 360 degrees of the SR motor.

  The power conversion circuit 20 includes a series connection of a U-phase upper arm switching element Sup and a U-phase lower arm diode Dun, a series connection of a U-phase upper arm diode Dup and a U-phase lower arm switching element Sun, and a V-phase upper arm switching element Series connection of Svp and V-phase lower arm diode Dvn, series connection of V-phase upper arm diode Dvp and V-phase lower arm switching element Svn, W-phase upper arm switching element Swp and W-phase lower arm diode Dwn And a W-phase upper arm diode Dwp and a series connection of the W-phase lower arm switching element Swn. Here, in the present embodiment, IGBTs are used as the U to W phase upper arm switching elements Sup, Svp, Swp and the U to W phase lower arm switching elements Sun, Svn, Swn. In the present embodiment, U to W phase upper arm diodes Dup, Dvp, Dwp correspond to “upper arm rectifying elements”, and U to W phase lower arm diodes Dun, Dvn, Dwn are “lower arm rectifying elements”. Equivalent to.

  Specifically, the connection point between the U-phase upper arm switching element Sup and the U-phase lower arm diode Dun and the connection point between the U-phase upper arm diode Dup and the U-phase lower arm switching element Sun are connected by a U-phase coil 22u. There is. The emitter of the U-phase upper arm switching element Sup and the cathode of the U-phase lower arm diode Dun are connected, and the collector of the U-phase upper arm switching element Sup is connected to the positive electrode terminal of the high voltage battery 10. Further, the anode of the U-phase lower arm diode Dun is connected to the negative terminal of the high voltage battery 10. On the other hand, the anode of the U-phase upper arm diode Dup and the collectors of the U-phase lower arm switching element Sun are connected, and the cathode of the U-phase upper arm diode Dup is connected to the positive terminal of the high voltage battery 10. Further, the emitter of the U-phase lower arm switching element Sun is connected to the negative terminal of the high voltage battery 10.

  The connection mode of the switching elements Svp, Svn, Swp, Swn and the diodes Dvp, Dvn, Dwp, Dwn constituting the V phase and the W phase is the same as that of the U phase. For this reason, in the present embodiment, the detailed description of the connection mode for the V phase and the W phase will be omitted.

  The motor control unit 30 includes a central processing unit (CPU) and a memory (not shown), and the central processing unit executes various programs stored in the memory to control the control amount (output torque) of the SR motor as its command value , Torque command value Trq *). The motor control device 30 detects a U-phase current sensor 32u detecting a current flowing through the U-phase coil 22u, a V-phase current sensor 32v detecting a current flowing through the V-phase coil 22v, and a current flowing through the W-phase coil 22w The detected value of the W-phase current sensor 32 w is input. The motor control device 30 also includes a voltage sensor 34 for detecting the voltage across the terminals of the smoothing capacitor 12 (the output voltage of the high voltage battery 10, the input voltage of the power conversion circuit 20), the rotation angle of the rotor of the SR motor (electricity A detection value of a rotation angle sensor 36 (for example, resolver) that detects the angle θ) is input. The motor control device 30 controls the output torque of the SR motor to the torque command value Trq * based on the detection values of these various sensors, and the upper arm switching element Sap (a = u, v, and v) configuring the power conversion circuit 20. w) and the lower arm switching element San output the operation signals gap and gan to operate the switching elements Sap and San.

  Specifically, the motor control device 30 includes an electric angular velocity calculation unit 30a, a modulation wave generation unit 30b, and an operation signal generation unit 30c. The electrical angular velocity calculation unit 30 a calculates an electrical angular velocity ω as a time differential value of the electrical angle θ detected by the rotation angle sensor 36. Further, the modulation wave generation unit 30 b generates the modulation wave α for each of u, v, and w phases based on the torque command value Trq *, the electrical angle θ, and the electrical angular velocity ω. The operation signal generation unit 30c generates operation signals gap and gan for operating the upper arm switching element Sap and the lower arm switching element San based on the modulated wave α output from the modulated wave generation unit 30b. Here, the modulation waves for each of the U to W phases are generated as waveforms mutually shifted by 120 ° at the electrical angle θ.

  The torque command value Trq * is input to the motor control device 30 from, for example, a control device higher than the motor control device 30 (for example, a control device that controls traveling control of the vehicle). Further, each phase of the SR motor is independent, and furthermore, each processing regarding each phase in the motor control device 30 is basically the same processing.

  Then, the setting method of the command voltage concerning this embodiment is demonstrated using FIG. Here, FIG. 2A shows a transition of a command value (hereinafter referred to as a command voltage V *) of an applied voltage of the coil 22 (U-phase coil 22u, V-phase coil 22v or W-phase coil 22w). b) shows the transition of the flux linkage φ of the coil 22. FIG. 2 shows the transition in the case where the electrical angular velocity ω is constant. The command voltage V * is set for each of the U-phase coil 22 u, the V-phase coil 22 v, and the W-phase coil 22 w.

  As illustrated, in the present embodiment, the command voltage V * is gradually changed in both the rising period (time t1 to t2 and t3 to t4) and the falling period (time t2 to t3) of the command voltage V *. The command voltage V * is set so that the waveform drawn by the command voltage V * continues in one cycle of the electrical angle θ (time t1 to t5). Here, the rising period is a period in which the command voltage V * rises (in other words, a period in which the change speed of the command voltage V * is higher than 0), and the falling period is a command voltage V * Falls (in other words, a period in which the change speed of the command voltage V * is lower than 0).

  In particular, in the present embodiment, the first sinusoidal waveform drawn by the command voltage V * in a period included in one cycle of the electrical angle θ and instructing energization of the coil 22 (time t1 to t4). The first axis L1 and the first axis defining the “0” of the command voltage V * after “(the waveform drawn of the command voltage V * from time t1 to tA and corresponding to the“ first waveform ”) A second sine waveform (with a command voltage V * being point-symmetrical to the first waveform with respect to a first waveform at an intersection point γ of a second axis L2 orthogonal to L1 and passing through the center of the conduction instruction period The command voltage V * is set so that it is a waveform to be drawn and corresponds to the “second waveform”). Here, the area enclosed by the first sine waveform and the first axis L1 is equal to the area enclosed by the second sine waveform and the first axis L1.

  The above setting of the command voltage V * is made for the purpose of reducing harmonic iron loss, vibration and noise of the SR motor. That is, by making the change of the interlinkage magnetic flux φ of the coil 22 gentle, it is possible to reduce harmonic iron loss, vibration and noise of the SR motor. Here, from the relationship that the time integral value of the applied voltage V of the coil 22 which is not affected by the time change of the inductance L becomes the interlinking magnetic flux φ of the coil 22, the rising period and falling period of the applied voltage V of the coil 22 By gradually changing the voltage V applied to the coil 22 at time t1, it is possible to make the change of the flux linkage φ gradual.

  Specifically, at time t1 to t2, by gradually increasing command voltage V * from 0 to first voltage V1 which is the upper limit value, applied voltage V of coil 22 also gradually rises from 0 to the upper limit value. Do. As a result, the flux linkage φ, which is an integral value of the applied voltage V, also gradually rises from 0, which is the timing value of the command voltage V *, to 0, the first flux amount φ1 which is a positive value.

  At subsequent times t2 to tA, the applied voltage V is also gradually lowered from the first voltage V1 to 0 by gradually decreasing the command voltage V * from the first voltage V1 to 0. As a result, the interlinking magnetic flux φ gradually rises to the second magnetic flux amount φ2 which is the upper limit value while lowering its rising speed (rising rate).

  At subsequent times tA to t3, by gradually decreasing the command voltage V * from 0 to the second voltage V2, the applied voltage V also gradually falls from 0 to the second voltage V2. Here, the second voltage V2 is a lower limit value of the command voltage V * and is a negative value. In particular, in the present embodiment, the absolute value of the second voltage V2 and the absolute value of the first voltage V1 are set to the same value. As a result of setting of the command voltage V *, the flux linkage φ gradually falls from the second magnetic flux amount φ2 to the first magnetic flux amount φ1.

  At subsequent times t3 to t4, by gradually increasing the command voltage V * from the second voltage V2 to 0, the applied voltage V also gradually increases from the second voltage V2 to 0. As a result, the flux linkage φ gradually falls to 0 while lowering its rate of descent (the rate of descent).

  In particular, by setting the command voltage V * so that the waveform drawn by the command voltage V * becomes a sine waveform, as shown in FIG. 2B, the waveform of the flux linkage φ in one cycle of the electrical angle θ Can be made into a sine wave shape, and the reduction effect such as harmonic iron loss can be increased.

  The current i flowing through the coil 22 changes so as to draw a peak smoothly between 0 and the upper limit value in the change of the command voltage V * in one cycle of the electrical angle θ. However, the above current flows as expected with respect to the command voltage V *. This situation is shown in FIG. Here, FIG. 3 (a) shows the transition of the inductance L of the coil 22, FIG. 3 (b) shows the transition of the command voltage V *, and FIG. 3 (c) shows the coil current i flowing through the coil 22. Show the transition of

  As illustrated, the temporal change in one cycle of the command voltage V * may be different from the temporal change in the one cycle of the coil current i. This is because, for example, the inductance L is different or the electrical angular velocity ω is different according to the electrical angle θ. In FIG. 3, when the same applied voltage V corresponding to the same command voltage V * is applied to the coil 22, the coil current i at the electrical angles θ1 to θ2 is from the coil current i at the electrical angles θ3 to θ4. Also illustrated the phenomenon of becoming large. This phenomenon occurs because the inductance L at the electrical angles θ1 to θ2 is smaller than the inductance L at the electrical angles θ3 to θ4.

  In the present embodiment, as described above, the command voltage V * is gradually changed and set without setting the command current i *. Here, the upper arm switching element Sap and the lower arm switching element San are turned on and off by pulse width modulation. Therefore, the modulation wave α standardized by dividing the command voltage V * by the DC voltage Vdc output from the high voltage battery 10 is set as the command voltage V *.

  FIG. 4 shows a procedure of modulated wave generation processing which is a premise of the present embodiment. This process is repeatedly performed by, for example, a predetermined cycle by the modulation wave generation unit 30b included in the motor control device 30.

  In this series of processing, first, at step S10, the torque command value Trq *, the electrical angle θ and the electrical angular velocity ω are acquired.

  In the following step S12, based on the acquired torque command value Trq *, the electrical angle θ and the electrical angular velocity ω, the command modulation rate α0, the ON phase θon which is the electrical angle θ instructing start of energization to the U-phase coil 22u The energization instruction width .theta.w (time t1 to t4 in FIG. 2 described above) which is the width of the electrical angle .theta. Instructing the energization continuation period from the time t1) and the ON phase .theta.on of FIG. The OFF phase θoff, which is the electrical angle θ for instructing the end of the energization to the U-phase coil 22u, corresponds to the time T4 in the previous figure. Here, command modulation rate α0 is a value obtained by dividing the amplitude of command voltage V * set as a sine waveform by DC voltage Vdc output from high voltage battery 10. Further, a period from when the electrical angle θ becomes the ON phase θon to when the energization instruction width θw passes is the above-mentioned energization instruction period. The command modulation rate α0, the ON phase θon, and the energization instruction width θw are related to the torque command value Trq * and the electric angular velocity ω, and a map in which the command modulation rate α0, the ON phase θon, and the energization instruction width θw are defined. It may be set using an equation.

  In the following step S14, it is determined whether or not the current electrical angle θ is a current application instruction period. Specifically, when a value obtained by subtracting the ON phase θon from the current electrical angle θ is a numerator and a value with a power instruction width θw as a denominator is defined as a determination parameter, the determination parameter is “0” or more and “ It is judged whether it is 1 "or less.

  If a negative determination is made in step S14, it is determined that the current electrical angle θ is not in the current application instruction period, and the process proceeds to step S16. In step S16, the modulation wave α is set to “0”. On the other hand, when an affirmative determination is made in step S14, it is determined that the current electrical angle θ is in the power supply instruction period, and the process proceeds to step S18. In step S18, the modulation wave α is generated by multiplying the sine function having the determination parameter and the product of “360 °” as an independent variable by the command modulation rate α0. When the processes of steps S16 and S18 are completed, this series of processes is temporarily ended.

  Incidentally, the value obtained by multiplying the modulated wave α generated by the process shown in FIG. 4 by the DC voltage Vdc output from the high voltage battery 10 is the command voltage V * shown in FIG. .

  Subsequently, FIG. 5 shows a procedure of voltage control processing according to the present embodiment. This process is repeatedly performed by, for example, a predetermined cycle by the operation signal generation unit 30c included in the motor control device 30. In the present embodiment, a series of processes shown in FIG. 5 constitute “voltage control means”.

  In this series of processes, first, in step S20, it is determined whether or not the modulation wave α output from the modulation wave generation unit 30b is the carrier signal Cs or more. In the present embodiment, a triangular wave signal is used as the carrier signal Cs. In the present embodiment, the minimum value of the carrier signal Cs is set to “−1”, and the maximum value is set to “1”.

  When an affirmative determination is made in step S20, the process proceeds to step S22, and both the upper arm switching element Sap and the lower arm switching element San are turned on. Thus, as illustrated in FIG. 6 for the U phase, current flows in the closed circuit including the high voltage battery 10, the U phase upper arm switching element Sup, the U phase coil 22u, and the U phase lower arm switching element Sun. A positive voltage "Vdc" is applied to coil 22u.

  On the other hand, when the determination in step S20 is negative, the process proceeds to step S24, in which both the upper arm switching element Sap and the lower arm switching element San are turned off. Thus, as illustrated in FIG. 7 for the U phase, a current flows in a closed circuit including the high voltage battery 10, the U phase lower arm diode Dun, the U phase coil 22u, and the U phase upper arm diode Dup, and the U phase coil 22u The negative voltage "-Vdc" is applied to the When the processes of steps S22 and S24 are completed, this series of processes is temporarily ended.

  According to the operation processing of the upper arm switching element Sap and the lower arm switching element San described above, as shown in FIG. 8, these switching elements Sap and San are subjected to pulse width modulation based on the comparison of the magnitude of the modulation wave α and the carrier signal Cs. It can be operated on and off. Thereby, the average applied voltage of the coil 22 in each period of the carrier signal Cs can be controlled to the command voltage V *. 8 (a) shows the transition of the modulation wave α and the carrier signal Cs, and FIG. 8 (b) shows the transition of the applied voltage V of the coil 22 and the command voltage V *.

  Here, the force acting in the radial direction of the rotation shaft of the SR motor, that is, the radial force Fr depends on the magnetic flux φ. Specifically, it can be expressed as Fr (θ) = K (θ) · φ 2 using a coefficient K (θ) determined by the shapes of the stator and the rotor and the magnetic flux φ. As shown in FIG. 2, the magnetic flux φ periodically changes in one cycle λ of the electrical angle θ. For this reason, the radial force Fr includes the n-th harmonic component with the reciprocal f of the period λ as the fundamental frequency.

  The nth harmonic component of the radial force Fr causes the generation of vibration and noise. In particular, when the nth harmonic component of the radial force Fr matches the mechanical natural frequency fm of the stator, mechanical resonance occurs, and large vibration and noise are generated from the SR motor.

  Therefore, to cancel the nth harmonic component of the radial force Fr, the sine wave voltage Vh * of the opposite phase of the frequency corresponding to the nth harmonic with respect to the above-mentioned command voltage V * (basic command voltage Vco *) It superimposes and it is set as the structure calculated as new command voltage Vinv *. With such a configuration, it is possible to suppress vibration and noise caused by the n-th harmonic component of the radial force Fr.

  FIG. 9A shows the waveform of the basic command voltage Vco *. The waveform of the basic command voltage Vco * shown in FIG. 9A is the same as the waveform of the command voltage V * shown in FIG. 2A. When the electrical angle θ becomes the ON phase θon, A sinusoidal voltage is applied. When the electrical angle θ becomes the OFF phase θoff, the application of the basic command voltage Vco * is stopped.

  FIG. 9B shows the waveform of the magnetic flux φ when the basic command voltage Vco * in FIG. 9A is applied to the coil 22. As shown in FIG. The waveform of the magnetic flux φ shown in FIG. 9 (b) is the same as the waveform of the magnetic flux φ shown in FIG. 2 (b). In the state where no voltage is applied, that is, from when the electrical angle θ changes from the OFF phase θoff to the ON phase θon, the magnetic flux φ has a slight DC component because the coil 22 is biased. When the electrical angle θ becomes the ON phase θon, the magnetic flux φ starts to increase as a voltage is applied. As the basic command voltage Vco * changes from a positive value to a negative value, the magnetic flux φ starts to decrease, and when the electrical angle θ becomes an OFF phase θoff, the magnetic flux φ becomes only a DC component due to the biased magnetization.

  FIG. 9C shows the waveform of the coefficient K (θ). The coefficient K (θ) is influenced by the magnetic flux φ in addition to the shapes of the stator and the rotor, and becomes approximately 0 until the electrical angle θ changes from the OFF phase θoff to the ON phase θon. The coefficient K (θ) starts to increase when the electrical angle θ becomes the ON phase θon, becomes the maximum at the electrical angle θ at which the magnetic flux φ becomes the maximum, and becomes approximately 0 when the electrical angle θ becomes the OFF phase θoff.

  FIG. 9D shows the waveform of the radial force Fr (θ) when the basic command voltage Vco * is applied to the coil 22. Since Fr (θ) = K (θ) · φ 2, as in the case of the magnetic flux φ, the radial force Fr (θ) is substantially zero during the period from the OFF phase θoff to the ON phase θon. It becomes. The radial force Fr (θ) starts to increase when the electric angle θ becomes the ON phase θon, becomes maximum at the electric angle θ at which the magnetic flux φ becomes the maximum, and becomes approximately 0 when the electric angle θ becomes the OFF phase θoff.

  FIG. 9E shows the order component of the radial force Fr (θ). The 0th-order component to the 4th-order component are larger than the 5th-order or more components. For this reason, the second to fourth order components are the main cause of mechanical resonance.

  Further, in the three-phase SR motor, 3n-order vibrations occur in the radial direction of the rotating shaft mainly due to torque ripple. If mechanical resonance due to the radial force Fr (θ) and mechanical resonance due to torque ripple occur simultaneously, the vibration and noise become significant, causing a problem. Therefore, in the present embodiment, the third harmonic voltage is superimposed on the basic command voltage Vco * so as to cancel the third harmonic component of the radial force Fr (θ).

  FIG. 10 shows a functional block diagram of the modulated wave generation unit 30b of this embodiment. The basic command voltage calculation unit 30d calculates a basic command voltage Vco * (basic modulation wave αco) based on the electrical angular velocity ω, the torque command value Trq *, and the electrical angle θ. Further, the corrected harmonic voltage calculation unit 30e calculates a corrected harmonic voltage Vh * (corrected modulation wave αh) based on the electric angular velocity ω and the torque command value Trq *. Then, adding unit 30 f adds basic command voltage Vco * (basic modulation wave αco) and corrected harmonic voltage Vh * (correction modulation wave αh), and adds the added value to command voltage Vinv * (modulation wave αinv). Output to the operation signal generation unit 30c.

  FIG. 11 is a flowchart showing command value calculation processing according to the present embodiment. In step S31, basic command voltage Vco * is calculated based on torque command value Trq *, electric angular velocity ω and electric angle θ.

  In step S32, it is determined whether a condition for performing the reduction of the radial force Fr (θ) is satisfied. It is determined based on the torque command value T * and the electrical angular velocity ω whether the condition for implementing the reduction of the radial force Fr (θ) is satisfied.

  Specifically, the reduction of the radial force Fr (θ) is performed on condition that the electrical angular velocity ω is such that the third harmonic component of the radial force Fr (θ) matches the natural frequency fm of the stator. Conduct (3 · ω / 2π = fm). Furthermore, the reduction of the radial force Fr (θ) is carried out under the condition that the torque command value Trq * falls within the predetermined range. Here, the range of the torque command value Trq * for performing the reduction of the radial force Fr (θ) is set to the torque in the steady running state, which is smaller than the torque for performing the acceleration of the vehicle. By performing such setting, priority can be given to torque output at the time of acceleration of the vehicle, and priority can be given to the effect of reducing vibration and noise at the time of steady traveling.

  If the condition for performing the reduction of the radial force Fr (θ) is not satisfied (S32: NO), the corrected harmonic voltage Vh * is set to 0 in step S33. If the condition for reducing the radial force Fr (θ) is satisfied (S32: YES), the frequency of the corrected harmonic voltage Vh * is determined based on the torque command value Trq * and the electrical angular velocity ω in step S34. Calculate the amplitude and phase. Here, the frequency of the corrected harmonic voltage Vh * mainly depends on the electrical angular velocity ω, and the amplitude of the corrected harmonic voltage Vh * mainly depends on the torque command value Trq *.

  In step S35, the command voltage Vinv * is calculated by adding the corrected harmonic voltage Vh * to the basic command voltage Vco *.

  FIG. 12A shows the waveform of the command voltage Vinv * calculated based on the command value calculation process shown in FIG. The waveform is obtained by adding the corrected harmonic voltage Vh * (third harmonic voltage) to the basic command voltage Vco * shown in FIG. 9A. 12 (b) shows the waveform of the magnetic flux φ when the command voltage Vinv * is applied to the coil 22, and FIG. 12 (c) shows the coefficient K (θ when the command voltage Vinv * is applied to the coil 22. 12D shows the radial force Fr (θ) when the command voltage Vinv * is applied to the coil 22. FIG.

  FIG. 12E shows the order component of the radial force Fr (θ) when the command voltage Vinv * is applied to the coil 22. By superimposing the correction harmonic voltage Vh * which is the third harmonic on the basic command voltage Vco *, the third-order component of the radial force Fr (θ) is substantially zero. This makes it possible to suppress machine resonance.

  The effects of this embodiment will be described below.

  The radial force Fr of the SR motor can be expressed using K (θ) determined from the shape of the stator and the shape of the rotor, and the magnetic flux φ (Fr (θ) = K (θ) · φ ^ 2) . In the present embodiment, the magnetic flux φ is controlled by adjusting the output voltage to the coil 22 (22u, 22v, 22w) (φ = ∫Vdt). Therefore, the corrected harmonic voltage Vh * having a specific cycle different from one cycle of the electrical angle θ is superimposed on the basic command voltage Vco *. Thereby, by reducing the magnetic flux having the specific cycle, it is possible to reduce the radial force having the specific cycle, and it is possible to reduce the vibration and noise of the specific cycle.

  When control is performed so that the output voltage to the coil 22 has a predetermined waveform in one cycle of the electric angle θ of the motor, an n-order harmonic is generated with a frequency that is the reciprocal of the one cycle of the electric angle θ as a fundamental frequency. The radial force Fr (θ) generated by the n-th harmonic causes vibration and noise. Therefore, by superimposing the n-th harmonic voltage Vh * on the basic command voltage Vco *, it is possible to cancel the n-th harmonic and reduce vibration and noise.

  When the corrected harmonic voltage Vh * is superimposed on the basic command voltage Vco *, there is a concern that the output of the motor may be reduced. Further, when the electrical angular velocity ω multiplied by n / 2π matches the natural frequency fm of the stator, mechanical resonance occurs, and the vibration and noise become remarkable. Also, for example, in the torque region which is not used regularly, it may be possible to temporarily allow vibration and noise. Therefore, on the condition that the electric angular velocity ω of the motor is a predetermined angular velocity (that is, the rotation speed of the motor is a predetermined value) or that the torque command value Trq * is a predetermined torque, the basic command voltage The configuration is such that the correction harmonic voltage Vh * is superimposed on Vco *. With such a configuration, it is possible to obtain the effect of reducing vibration and noise while preferably suppressing the decrease in output of the motor.

  In the present embodiment, by setting the output voltage to the coil 22 based on the torque command value Trq * and the electrical angle θ, it is possible to control the magnetic flux of the coil 22 while controlling the output torque of the motor.

  The amplitude of the output voltage, that is, the amplitude of the magnetic flux φ and the radial force Fr changes in accordance with the torque command value Trq *. Further, the frequency of the output voltage, that is, the frequency of the magnetic flux φ and the radial force Fr changes in accordance with the electric angular velocity ω of the motor. Therefore, the frequency and the amplitude of the corrected harmonic voltage Vh * (sine wave voltage) are set based on the torque command value Trq * and the electric angular velocity ω (that is, the rotational speed of the motor). With such a configuration, it is possible to preferably reduce vibration and noise of a specific cycle.

(Other embodiments)
The voltage drop due to the resistance component of the coil 22 may be added to the basic command voltage Vco * as a correction value. Specifically, as shown in the flowchart of FIG. 13, between step S31 and step S32 of FIG. 12, the resistance component R of the coil 22 and the current i flowing through the coil 22 with respect to the basic command voltage Vco *. The configuration may be such that the step S41 of adding the product is provided.

  The corrected harmonic voltage Vh * may be superimposed on the basic command voltage Vco * so as to always cancel the frequency component corresponding to the natural frequency fm of the stator.

  In the above embodiment, the basic command voltage Vco * of a sine wave is used. However, the basic command voltage Vco * of a rectangular wave as shown in FIG. 14 may be used by changing this.

  In the above embodiment, the correction harmonic voltage Vh * is superimposed on the basic command voltage Vco * so as to cancel the third harmonic. This may be changed, and the corrected harmonic voltage Vh * may be superimposed so as to cancel the n-th harmonic (n is a natural number of 2 or more).

  In the above embodiment, after determining whether the condition for reducing the radial force Fr (θ) is satisfied, the corrected harmonic voltage with respect to the basic command voltage Vco * when the condition is satisfied. It was set as the structure which superimposes Vh *. This may be changed so that the n-order corrected harmonic voltage Vh * is always superimposed on the basic command voltage Vco *. For example, the third harmonic may be configured to always superimpose the corrected harmonic voltage Vh * on the basic command voltage Vco *.

  20: Power conversion circuit (voltage output circuit), 22: coil, 30: motor control device.

Claims (4)

In a switched reluctance motor having a stator having a coil (22) and a rotor rotatably supported and rotated by application of a voltage to the coil, a voltage output circuit (20) is connected to the coil. A control device (30) for controlling the motor by adjusting an output voltage to be output,
Basic command voltage setting means for setting a basic command voltage such that an interlinkage magnetic flux generated in the coil has a predetermined predetermined waveform by applying a voltage to the coil in one cycle of an electrical angle of the motor;
Superposition means for superposing a sine wave voltage having a specific cycle different from one cycle of the electrical angle on the basic command voltage, and setting the output voltage of the voltage output circuit as a command voltage to be commanded;
Voltage control means for controlling the output voltage of the voltage output circuit based on the command voltage;
Bei to give a,
The superimposing means uses a frequency that is the reciprocal of one cycle of the electrical angle as a fundamental frequency, and an n-th harmonic having a frequency of n times the fundamental frequency (n is a natural number of 2 to 4) as the sine wave voltage A motor control apparatus characterized in that a voltage is superimposed on the basic command voltage and set as the command voltage . The superimposing unit is configured to set the electrical angle to 1 at least one of the following conditions: the rotational speed of the motor is a predetermined value, and the torque command value for instructing the output torque of the motor is a predetermined value. The motor control device according to claim 1 , wherein a sine wave voltage having a cycle different from the cycle is superimposed on the basic command voltage and set as the command voltage. The motor control according to claim 1 or 2 , wherein the command voltage setting means sets the basic command voltage based on a torque command value for commanding an output torque of the motor and the electrical angle. apparatus. 4. The apparatus according to claim 3 , wherein said superimposing means comprises means for setting the frequency and amplitude of a sine wave voltage to be superimposed on said basic command voltage based on said torque command value and the rotational speed of said motor. Motor controller as described.