JP2016063649A - Motor controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a controller that is able to suitably prevent noise and vibration having a specific cycle in an SR motor.SOLUTION: A switched reluctance motor comprises: a stator having a coil 22; and a rotor supported so as to be rotatable and rotated by the application of voltage to the coil 22. The motor is provided with a motor controller 30 that controls the motor by adjusting voltage output to the coil 22 from a voltage conversion circuit 20. In the motor controller, a basic command voltage is set such that in one period of the electric angle of the motor, an interlinkage flux generated in the coil 22 by the application of voltage to the coil 22 has a predetermined wave shape. A sinusoidal voltage with a specific period different from the one period of the electric angle is superposed on the basic command voltage. Voltage output from the voltage conversion circuit 20 is set as a command voltage that issues a command. On the basis of the command voltage, voltage output from the voltage conversion circuit 20 is controlled.SELECTED DRAWING: Figure 1

Description

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

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

Japanese 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 lowered, and the effect of reducing vibration and noise is insufficient. Further, while it is possible to suppress a steep change in the magnetic flux φ, it is not possible to suppress the pulsation of the radial force, and the effect of reducing vibration and noise is insufficient.

  Therefore, a method of controlling the magnetic flux φ by adjusting the applied voltage of the coil, instead of controlling the current flowing through the coil, can be considered. By adjusting the voltage applied to the coil, the magnetic flux φ generated in the coil can be directly controlled. By directly controlling the magnetic flux φ, it is possible to sufficiently reduce noise and vibration even in the above-described non-linear region, and to suppress the pulsation of the radial force. Here, when adjusting the applied voltage of the coil to control the magnetic flux φ, there is a demand for suppressing vibration and noise having a specific period for the purpose of suppressing resonance.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a control device that can suitably suppress noise and vibration having a specific period 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 that is rotatably supported and rotates when a voltage is applied to the coil. A motor control device (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 the electrical angle of the motor. Basic command voltage setting means (30) for setting the basic command voltage so that the interlinkage magnetic flux generated in the coil has a predetermined waveform, and a sine wave voltage having a specific cycle different from one cycle of the electrical angle. Superimposing means for superimposing on the basic command voltage and setting as a command voltage for commanding the output voltage of the voltage output circuit, and based on the command voltage, the output of the voltage output circuit 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 by 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 applied voltage of the coil. Thus, a sine wave voltage having a specific period different from one period of the rotation angle is superposed on the command voltage. As a result, the magnetic force having the specific period is reduced (φ = ｄvdt), so that the radial force having the specific period can be reduced. Thereby, the vibration and noise of a specific period can be reduced.

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 modulation wave production | generation process used as 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. 5 is a timing chart showing an example of pulse width modulation according to the embodiment. The figure which shows the basic command voltage, the magnetic flux, the coefficient, the waveform of radial force, and the order component of radial force when a basic command voltage is applied to a coil. The functional block diagram of a modulation wave generation part. The flowchart which shows the procedure of the modulation wave production | generation process concerning embodiment. The figure which shows the command voltage, the magnetic flux, the coefficient, the waveform of radial force, and the order component of radial force when a harmonic voltage is superimposed. The flowchart which shows the procedure of the modulation wave production | generation process 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 referred to as an SR motor) as an in-vehicle main machine will be described with reference to the drawings.

  As shown in FIG. 1, the high voltage battery 10 is a secondary battery whose terminal voltage is, for example, 100 V or more (288 V). As the high voltage battery 10, for example, a lithium ion secondary battery or a nickel hydride 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. A motor generator as an in-vehicle main machine is connected to the power conversion circuit 20. The motor generator is an SR motor. The SR motor has a stator (stator) having a coil 22 and a rotor (rotor) that is rotatably supported and 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 22u, a V-phase coil 22v, and a W-phase coil 22w is used as the SR motor. In addition, the rotor of the SR motor of the present embodiment has 6 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 U-phase upper arm switching element Sup and a U-phase lower arm diode Dun connected in series, a U-phase upper arm diode Dup and a U-phase lower arm switching element Sun connected in series, and a V-phase upper arm switching element. Svp and V-phase lower arm diode Dvn in series connection, V-phase upper arm diode Dvp and V-phase lower arm switching element Svn in series, W-phase upper arm switching element Swp and W-phase lower arm diode Dwn in series connection , And a serial connection body of a W-phase upper arm diode Dwp and a W-phase lower arm switching element Swn. Here, in this embodiment, IGBT is 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, the U to W phase upper arm diodes Dup, Dvp, and Dwp correspond to “upper arm rectifier elements”, and the U to W phase lower arm diodes Dun, Dvn, and Dwn become “lower arm rectifier 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 the U-phase coil 22u. Yes. The emitter of U-phase upper arm switching element Sup and the cathode of U-phase lower arm diode Dun are connected to each other, and the collector of U-phase upper arm switching element Sup is connected to the positive terminal of high-voltage battery 10. 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 collector of the U-phase lower arm switching element Sun are connected to each other, and the cathode of the U-phase upper arm diode Dup is connected to the positive terminal of the high-voltage battery 10. 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 this embodiment, the detailed description of the connection aspect about V phase and W phase is abbreviate | omitted.

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

  Specifically, the motor control device 30 includes an electrical angular velocity calculation unit 30a, a modulated wave generation unit 30b, and an operation signal generation unit 30c. The electrical angular velocity calculation unit 30a calculates the electrical angular velocity ω as a time differential value of the electrical angle θ detected by the rotation angle sensor 36. Also, the modulation wave generator 30b generates a modulation wave α for each of the 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 modulation wave α output from the modulation wave generation unit 30b. Here, the modulated waves for each of the U to W phases are generated as waveforms that are shifted from each other by 120 ° in electrical angle θ.

  Note that 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 vehicle travel control). In addition, each phase of the SR motor is independent, and each of the processes related to each phase in the motor control device 30 is basically the same process.

  Subsequently, a command voltage setting method according to the present embodiment will be described with reference to FIG. Here, FIG. 2A shows the transition of the command value (hereinafter, command voltage V *) of the 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 when the electrical angular velocity ω is constant. Command voltage V * is set for each of U-phase coil 22u, V-phase coil 22v, and W-phase coil 22w.

  As shown in the figure, in this embodiment, the command voltage V * is gradually changed in both the rising period (time t1 to t2, 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 * is continuous in one cycle of the electrical angle θ (time t1 to t5). Here, the rising period is a period during which the command voltage V * increases (in other words, a period during which the change rate of the command voltage V * is higher than 0), and the falling period is the command voltage V *. Is a period (in other words, a period in which the change rate of the command voltage V * is lower than 0).

  In particular, in the present embodiment, the first sine waveform drawn by the command voltage V * in the energization instruction period (time t1 to t4) that is included in one cycle of the electrical angle θ and instructs energization of the coil 22. The first axis line L1 and the first axis line defining “0” of the command voltage V * after (the waveform drawn by the command voltage V * from time t1 to tA and corresponding to “first waveform”) A second sine waveform that is symmetric with respect to the first waveform with respect to the intersection γ of the second axis L2 that is orthogonal to L1 and passes through the center of the energization instruction period (by the time tA to t4, the command voltage V * The command voltage V * is set so that the waveform to be drawn is equivalent to the “second waveform”). Here, the area surrounded by the first sine waveform and the first axis L1 is equal to the area surrounded 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, the harmonic iron loss, vibration and noise of the SR motor can be reduced. Here, from the relationship in which the time integral value of the applied voltage V of the coil 22 that is not affected by the time variation of the inductance L becomes the linkage flux φ of the coil 22, the rising period and falling period of the applied voltage V of the coil 22 In FIG. 2, the change in the flux linkage φ can be moderated by gradually changing the applied voltage V of the coil 22.

  Specifically, at time t1 to t2, the command voltage V * is gradually increased from 0 to the first voltage V1, which is the upper limit value, so that the applied voltage V of the coil 22 also gradually increases from 0 to the upper limit value. To do. As a result, the interlinkage magnetic flux φ, which is an integral value of the applied voltage V, also gradually increases from 0, which is the timing value when the command voltage V * is 0, to the first magnetic flux amount φ1, which is a positive value.

  At subsequent times t2 to tA, the command voltage V * is gradually decreased from the first voltage V1 to 0, so that the applied voltage V is also gradually decreased from the first voltage V1 to 0. As a result, the interlinkage magnetic flux φ gradually increases to the second magnetic flux amount φ2 that is the upper limit value while lowering the rate of increase (rate of increase).

  At subsequent times tA to t3, the applied voltage V is gradually decreased from 0 to the second voltage V2 by gradually decreasing the command voltage V * from 0 to the second voltage V2. Here, the second voltage V2 is a lower limit value of the command voltage V * and 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 the command voltage V *, the interlinkage magnetic flux φ gradually decreases from the second magnetic flux amount φ2 to the first magnetic flux amount φ1.

  At subsequent times t3 to t4, the applied voltage V is gradually increased from the second voltage V2 to 0 by gradually increasing the command voltage V * from the second voltage V2 to 0. As a result, the interlinkage magnetic flux φ gradually decreases to 0 while decreasing its descending speed (decreasing rate).

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

  Note that the current i flowing through the coil 22 smoothly changes 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 current flows in a manner corresponding to the command voltage V *. This situation is shown in FIG. 3A shows the transition of the inductance L of the coil 22, FIG. 3B shows the transition of the command voltage V *, and FIG. 3C shows the coil current i flowing through the coil 22. Shows the transition.

  As shown in the figure, the change with time in one cycle of the command voltage V * may be different from the change with time 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. FIG. 3 shows that 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 greater than the coil current i at the electrical angles θ3 to θ4. The phenomenon of increasing is also illustrated. 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 this 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. For this reason, the modulated wave α normalized 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 that is a premise of the present embodiment. This process is repeatedly executed at a predetermined cycle, for example, by the modulated wave generation unit 30b included in the motor control device 30.

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

  In the subsequent step S12, based on the acquired torque command value Trq *, electrical angle θ, and electrical angular velocity ω, the command modulation rate α0, the ON phase θon that is the electrical angle θ instructing the start of energization of the U-phase coil 22u (first) 2 and the energization instruction width θw (time t1 to t4 in FIG. 2), which is the width of the electrical angle θ instructing the energization continuation period from the ON phase θon. Note that the OFF phase θoff, which is the electrical angle θ instructing the end of energization of the U-phase coil 22u, corresponds to time T4 in the previous figure. Here, the command modulation rate α0 is a value obtained by dividing the amplitude of the command voltage V * set as a sine waveform by the DC voltage Vdc output from the high-voltage battery 10. The period from when the electrical angle θ becomes the ON phase θon to when the energization instruction width θw elapses is the 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 electrical angular velocity ω, and the command modulation rate α0, the ON phase θon, and the energization instruction width θw are defined. What is necessary is just to set using a numerical formula.

  In a succeeding step S14, it is determined whether or not the current electrical angle θ is the energization instruction period. Specifically, if a value obtained by subtracting the ON phase θon from the current electrical angle θ is defined as a numerator and a value having the energization instruction width θw as a denominator is defined as a determination parameter, the determination parameter is “0” or more and “ It is determined 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 the energization 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 a positive determination is made in step S14, it is determined that the current electrical angle θ is the energization instruction period, and the process proceeds to step S18. In step S18, the modulation wave α is generated by multiplying the command modulation factor α0 by a sine function having the determination parameter and the multiplication value of “360 °” as an independent variable. In addition, when the process of step S16, S18 is completed, this series of processes is once complete | finished.

  Incidentally, a value obtained by multiplying the modulated wave α generated by the processing shown in FIG. 4 by the DC voltage Vdc output from the high voltage battery 10 becomes 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 executed, for example, at a predetermined cycle by the operation signal generation unit 30c included in the motor control device 30. In the present embodiment, the series of processing shown in FIG. 5 constitutes “voltage control means”.

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

  If a positive 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. Thereby, as illustrated in FIG. 6 for the U phase, a current flows through a 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, and the U phase A positive voltage “Vdc” is applied to the coil 22u.

  On the other hand, when a negative determination is made in step S20, the process proceeds to step S24, and both the upper arm switching element Sap and the lower arm switching element San are turned off. Thereby, as illustrated in FIG. 7 for the U phase, a current flows through 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 A negative voltage “−Vdc” is applied to In addition, when the process of step S22 and S24 is completed, this series of processes is once complete | finished.

  According to the above-described operation processing of the upper arm switching element Sap and the lower arm switching element San, as shown in FIG. 8, the switching elements Sap and San are changed by pulse width modulation based on the magnitude comparison of the modulated wave α and the carrier signal Cs. Can be turned 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 *. 8A shows the transition of the modulation wave α and the carrier signal Cs, and FIG. 8B shows the transition of the applied voltage V and the command voltage V * of the coil 22.

  Here, the force acting in the radial direction of the rotating 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 shape of the stator and the rotor and the magnetic flux φ. As shown in FIG. 2, the magnetic flux φ changes periodically in one cycle λ of the electrical angle θ. For this reason, the radial force Fr includes an n-order harmonic component with the reciprocal f of the period λ as a fundamental frequency.

  The nth harmonic component of the radial force Fr causes vibration and noise. In particular, when the nth-order 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, in order to cancel the n-order harmonic component of the radial force Fr, a sinusoidal voltage Vh * having a phase opposite to the frequency corresponding to the n-order harmonic is applied to the command voltage V * (basic command voltage Vco *) described above. Superimpose and calculate as a new command voltage Vinv *. By adopting such a configuration, it is possible to suppress vibration and noise caused by the nth harmonic component of the radial force Fr.

  FIG. 9A shows a 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, the waveform of the energization instruction width θw is obtained. 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 a waveform of the magnetic flux φ when the basic command voltage Vco * of FIG. 9A is applied to the coil 22. The waveform of the magnetic flux φ shown in FIG. 9B is the same as the waveform of the magnetic flux φ shown in FIG. In a state where no voltage is applied, that is, until 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 demagnetized. When the electrical angle θ becomes the ON phase θon, the magnetic flux φ starts to increase by applying a voltage. When 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 the OFF phase θoff, the magnetic flux φ becomes only a direct current component due to demagnetization.

  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 shape of the stator and the rotor, and is substantially zero until the electrical angle θ changes from the OFF phase θoff to the ON phase θon, as with the magnetic flux φ. The coefficient K (θ) starts to increase when the electrical angle θ reaches the ON phase θon, becomes maximum at the electrical angle θ at which the magnetic flux φ becomes maximum, and becomes substantially zero when the electrical angle θ reaches the OFF phase θoff.

  FIG. 9D shows a 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, the radial force Fr (θ) is substantially 0 until the electrical angle θ changes from the OFF phase θoff to the ON phase θon, similarly to the magnetic flux φ. It becomes. The radial force Fr (θ) starts to increase when the electrical angle θ reaches the ON phase θon, reaches a maximum at the electrical angle θ at which the magnetic flux φ becomes a maximum, and becomes substantially zero when the electrical angle θ reaches 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 higher order component. For this reason, secondary to quaternary components are the main causes of mechanical resonance.

  Further, in the three-phase SR motor, 3n-order vibration is generated in the radial direction of the rotary shaft mainly due to torque ripple. If the mechanical resonance due to the radial force Fr (θ) and the mechanical resonance due to the torque ripple occur at the same time, there will be a problem because the vibration and noise become extremely large. 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 generator 30b of the present 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. The corrected harmonic voltage calculation unit 30e calculates a corrected harmonic voltage Vh * (corrected modulated wave αh) based on the electrical angular velocity ω and the torque command value Trq *. Then, in the addition unit 30f, the basic command voltage Vco * (basic modulation wave αco) and the corrected harmonic voltage Vh * (correction modulation wave αh) are added, and the added value is used as the command voltage Vinv * (modulation wave αinv). Is output to the operation signal generator 30c.

  FIG. 11 is a flowchart showing the command value calculation process of this embodiment. In step S31, a basic command voltage Vco * is calculated based on the torque command value Trq *, the electrical angular velocity ω, and the electrical angle θ.

  In step S32, it is determined whether a condition for reducing the radial force Fr (θ) is satisfied. Whether or not the condition for reducing the radial force Fr (θ) is satisfied is determined based on the torque command value T * and the electrical angular velocity ω.

  Specifically, the radial force Fr (θ) is reduced on condition that the third harmonic component of the radial force Fr (θ) is an electrical angular velocity ω that matches the natural frequency fm of the stator. Implement (3 · ω / 2π = fm). Further, the radial force Fr (θ) is reduced on condition that the torque command value Trq * belongs to a predetermined range. Here, the range of the torque command value Trq * for reducing the radial force Fr (θ) is set to a torque in a steady running state that is smaller than the torque for accelerating the vehicle. By making such a setting, priority can be given to torque output when the vehicle is accelerated, and priority can be given to vibration and noise reduction effects during steady running.

  If the condition for reducing the radial force Fr (θ) is not satisfied (S32: NO), the corrected harmonic voltage Vh * is set to 0 in step S33. When the condition for reducing the radial force Fr (θ) is satisfied (S32: YES), in step S34, based on the torque command value Trq * and the electrical angular velocity ω, the frequency of the corrected harmonic voltage Vh *, 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 a waveform of the command voltage Vinv * calculated based on the command value calculation process shown in FIG. The waveform is obtained by adding a corrected harmonic voltage Vh * (third harmonic voltage) to the basic command voltage Vco * shown in FIG. FIG. 12B shows the waveform of the magnetic flux φ when the command voltage Vinv * is applied to the coil 22, and FIG. 12C shows the coefficient K (θ when the command voltage Vinv * is applied to the coil 22. ), And FIG. 12D shows the radial force Fr (θ) when the command voltage Vinv * is applied to the coil 22.

  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 corrected harmonic voltage Vh *, which is the third harmonic, on the basic command voltage Vco *, the third component of the radial force Fr (θ) is substantially zero. Thereby, it is possible to suppress mechanical resonance.

  Hereinafter, effects in the present embodiment will be described.

  The radial force Fr of the SR motor can be expressed by 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 this 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 period different from one period of the electrical angle θ is superposed on the basic command voltage Vco *. Thereby, it becomes possible to reduce the radial force which has the specific period by reducing the magnetic flux which has the specific period, and can reduce the vibration and noise of a specific period.

  When control is performed so that the output voltage to the coil 22 has a predetermined waveform in one cycle of the electrical angle θ of the motor, an nth-order harmonic is generated with a frequency that is the reciprocal of one cycle of the electrical angle θ as a fundamental frequency. The radial force Fr (θ) generated by the nth order harmonic causes vibration and noise. Therefore, by superimposing the nth harmonic voltage Vh * on the basic command voltage Vco *, it is possible to cancel the nth 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 is reduced. Further, when the value obtained by multiplying the electrical angular velocity ω by n / 2π matches the natural frequency fm of the stator, mechanical resonance occurs, and vibration and noise become remarkable. In addition, for example, in a torque region that is not regularly used, vibration and noise may be temporarily allowed. Therefore, the basic command voltage is set on condition that the electrical angular velocity ω of the motor is a predetermined angular velocity (that is, the rotational speed of the motor is a predetermined value) or the torque command value Trq * is a predetermined torque. The corrected harmonic voltage Vh * is superimposed on Vco *. With such a configuration, it is possible to obtain an effect of reducing vibration and noise while suitably suppressing a decrease in the output of the motor.

  In this embodiment, the magnetic flux of the coil 22 can be controlled while controlling the output torque of the motor by setting the output voltage to the coil 22 based on the torque command value Trq * and the electrical angle θ.

  The amplitude of the output voltage, that is, the amplitude of the magnetic flux φ and the radial force Fr changes according to 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 according to the electric angular velocity ω of the motor. Thus, the frequency and amplitude of the corrected harmonic voltage Vh * (sinusoidal voltage) are set based on the torque command value Trq * and the electrical angular velocity ω (that is, the rotational speed of the motor). By setting it as such a structure, the vibration and noise of a specific period can be reduced suitably.

(Other embodiments)
A voltage drop due to the resistance component of the coil 22 may be added as a correction value to the basic command voltage Vco *. 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 are compared with the basic command voltage Vco *. What is necessary is just to set it as the structure which provides step S41 which adds a product.

  The correction harmonic voltage Vh * may be superposed on the basic command voltage Vco * so that the frequency component corresponding to the natural frequency fm of the stator is always canceled.

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

  In the above embodiment, the corrected 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 each nth harmonic (n is a natural number of 2 or more).

  In the above embodiment, it is determined whether or not the condition for reducing the radial force Fr (θ) is satisfied, and the corrected harmonic voltage is corrected 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 nth-order corrected harmonic voltage Vh * is always superimposed on the basic command voltage Vco *. For example, a configuration may be adopted in which the third harmonic is corrected and the corrected harmonic voltage Vh * is always superimposed on the basic command voltage Vco *.

  20 ... Power conversion circuit (voltage output circuit), 22 ... Coil, 30 ... Motor control device.

Claims (5)

In a switched reluctance motor having a stator having a coil (22) and a rotor that is rotatably supported and rotates when a voltage is applied to the coil, the voltage output circuit (20) 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 so that an interlinkage magnetic flux generated in the coil by applying a voltage to the coil has a predetermined waveform in one cycle of the electrical angle of the motor;
Superimposing means for superimposing a sine wave voltage having a specific cycle different from one cycle of the electrical angle on the basic command voltage, and setting the command voltage to command the output voltage of the voltage output circuit;
Voltage control means for controlling the output voltage of the voltage output circuit based on the command voltage;
A motor control device comprising:   The superimposing means has a frequency that is the reciprocal of one cycle of the electrical angle as a fundamental frequency, and the sine wave voltage has an n-th harmonic voltage having a frequency n times (n is a natural number of 2 or more) the fundamental frequency. Is superimposed on the basic command voltage and set as the command voltage.   The superimposing means sets the electrical angle of 1 on the condition that at least one of a rotational speed of the motor is a predetermined value and a torque command value for instructing an output torque of the motor is a predetermined value. The motor control device according to claim 1, wherein a sine wave voltage having a period different from the period is superimposed on the basic command voltage and set as the command voltage.   The said command voltage setting means sets the said basic command voltage based on the torque command value which commands the output torque of the said motor, and the said electrical angle, The any one of Claim 1 thru | or 3 characterized by the above-mentioned. The motor control device described in 1.   5. The superimposing means comprises means for setting the frequency and amplitude of a sine wave voltage to be superimposed on the basic command voltage based on the torque command value and the rotational speed of the motor. The motor control apparatus described.